Biomarkers Promote Anti-tumor Drug Development

Biomarkers are the most direct and rapid diagnostic tools. Their screening and acquisition can play an important role in disease diagnosis, development, treatment, and efficacy monitoring. It is also an important target for drug development.

Biomarker refers to a biochemical indicator that can objectively measure and evaluate changes or possible changes in system, organ, tissue, cell and subcellular structure or function. It has a very wide range of uses and can be used for disease diagnosis and judgment. Disease staging or evaluation of the safety and efficacy of new drugs or new therapies in the target population can also help researchers to propose more effective treatments, especially in chronic diseases such as cancer, cardiovascular disease, diabetes, and neurological disorders. It has important value in the prevention and control of complex diseases.

Biomarkers in Cancer

  1. Nat Med: Chinese scientists discover new prostate cancer biomarkersthat are expected to improve individualized therapy for cancer

In a study published in the international journal Nature Medicine, researchers from Fudan University and Mayo Clinic in China identified a new mechanism of prostate cancer resistance to therapy through joint research. The development of new prostate cancer therapies provide ideas and hopes. In the article, the researchers explained that the mutations in the SPOP gene play a key role in the drug resistance of prostate cancer. The SPOP gene mutation is the most frequent genetic mutation in primary prostate cancer. These mutations are in the cancer pair. BET inhibitor drugs play an important role in the development of tolerance.

  1. Cell-metabolism:A team of scientists in Australia recently discovered a new type of lung cancer biomarker. These cancers have also been found to produce specific metabolites that may be identified in plasma samples, thereby increasing the hope that diagnostic blood test methods for such diseases can be developed in the future.

Kate Sutherland, co-director of the study, said, “One-fifth of the lung adenocarcinomas have changed in the KEAP1 / NRF2 pathway, indicating that it is a major cancer driver. These cancers are very aggressive and resistant to standard therapies. Force and poor prognosis, so new treatments are urgently needed.”

Up to 40% of lung cancers are lung adenocarcinomas, and one in five of these specific tumors are resistant to chemotherapy and radiation. The new study suggests that these specific cancers may respond well to a new generation of anti-PD-1 and anti-CTLA-4 immunotherapies. The ability to easily and quickly identify these specific tumors will enable physicians to better identify those who respond best to new immunotherapy treatments.

Another result of this new study was the discovery of unique metabolic markers that can be found in blood samples, pointing out potential early detection blood tests. “We worked with our colleague Dr. David De Souza and Prof. Malcolm McConville of Bio21 to identify a unique ‘breadcrumb’ trace of these cancers in the blood,” Sutherland said. “We hope that this test will identify patients who may respond to immunotherapy, and may also be a simple non-invasive blood test that can detect these lung cancers early.”

This study currently only finds this molecular pathway in animal models, so the next stage is to validate these results in human lung samples. Since then, clinical applications may take some time to become a reality, but this finding is critical to creating blood tests that both diagnose lung cancer and guide doctors to the most likely successful treatment.

  1. Nature Communications:Researchers from the National Cancer Research Center (CNIO) in Spain have successfully identified biomarkers for breast cancerthat can be classified for the first time. This is the first time that a curable patient can be distinguished from a patient who may relapse. Open. It also identified new pharmacological indicators and indicated that combination therapy with existing drugs may be effective in patients with these indicators.

Specifically, they identified six protein kinases whose functional status predicts the evolution of triple-negative breast cancer. In addition, researchers have found a way to detect these proteins in hospitals, so in the future it may develop into a routine clinical trial, just like the genetic analysis of any tumor today.

From genomics to proteomics

Research on cancer genomics for decades has revealed dominant gene mutations in many cancers that determine tumor progression and guide the design of individualized therapeutic approaches. This type of specific treatment for each type of tumor is more effective than traditional chemotherapy and is a major cause of advances in cancer treatment in recent years.

However, triple-negative breast cancer is caused by a variety of mutations that work together in a unique combination of each patient. To date, no dominant gene mutations have been identified that provide prognostic indicators or drug treatment responses.

To achieve this goal, CNIO researchers chose not to analyze the genes involved in triple-negative breast cancer, but to analyze their products: synthesize proteins sorted by these genes. Their hypothesis is that many of the patient’s genetic changes can be translated into an identifiable pattern of functional status of all tumor proteins and their proteomes – activation or not.

The experimental results were very successful. In a tumor sample of 34 patients, the researchers discovered biochemical markers of tumor protein activation. Although the initial number of candidates exceeds two million, with the help of sophisticated bioinformatics tools, they found that among all these signals, accurate combinations can only be found in patients who have relapsed. These proteins are activated by kinases, which in turn are proteins, so the next step is to find the kinase responsible for this signal. Finally, the study identified six kinases that led to the formation of a proliferating pattern of proteomes in relapsed patients.

Six kinases indicate possible recurrence: We currently know that these six kinases play a key role in triple negative breast cancer. In this study, the authors validated the results of 170 patients and confirmed the value of these six kinases as markers. Patients who do not have these proteins activated have a 95% chance of being cured, or at least not relapsed 12 years after treatment. However, even if one of the six kinases is active, the risk of recurrence increases tenfold.

New clinical trials targeting kinase activation: Analysis of the functional status of proteins is not currently routinely tested in hospitals, but the authors have translated the activation pattern of kinases into immunohistochemical indicators that can be easily analyzed in hospitals. The goal is to determine whether these six kinases can be routine clinical trials, just like the genetic profiling of any tumor today.

Currently, researchers are focusing on other markers of disease, including standardized kinase diagnostic tests, and clinical trials of patients with advanced disease using the therapeutic combinations described herein.

  1. Int J Cancer:Colorectal cancer biomarkers–application of fecal microbes in the detection of colorectal cancer.

Colorectal Cancer (CRC) is the second leading cause of cancer death in the Western world. CRC In most cases, genomic mutations, such as the APC/wnt signaling pathway, induce cell proliferation, which in turn leads to adenoma formation. The gradual accumulation of a driver mutation eventually leads to the formation of invasive tumors. If the CRC can be diagnosed at an early stage, the five-year survival rate can reach 80% or more. If the tumor cells have metastasized in the advanced stage, the five-year survival rate is less than 10%. Therefore, if early screening can be done in various countries, the mortality rate of CRC can be reduced.

The current fecal occult blood test (FOBT) is the most widely used colon cancer screening method, but its sensitivity and specificity for CRC detection is not high; colonoscopy is currently the most effective method for diagnosing CRC, but the operation is complicated and the patient experience is poor. Previous studies have found that changes in the intestinal flora are associated with CRC, but the potential of microbes as markers for colorectal cancer screening has not been clearly elucidated.

Therefore, researchers from Sweden used a nested case-control study to investigate the use of three microbial markers in fecal clBA + bacteria, afa-C+ diffuse E. coli, and Fusobacterium nucleatum in 238 subjects. The case of potential screening markers for CRC diagnosis.

The researchers found that clBA+ bacteria and individual markers of Fusobacterium nucleatum were more abundant in the stool of colorectal cancer patients and had higher specificity in predicting cancer (81.5% and 76.9%, respectively), and their sensitivity. They were 56.4% and 69.2%, respectively. In a combined trial of clBA+ bacteria and Fusobacterium nucleatum, the specificity of CRC diagnosis was 63.1% and the sensitivity was 84.6%.

The findings of this study support the ability of microbes in feces to serve as potential non-invasive biomarkers for CRC detection, and the method has potential value. The researchers suggest that, in the future, microbial markers may be an important screening strategy for patients with CRC who have “high risk” for other diagnostic methods such as colonoscopy.


[1] Eklöf V, Löfgren-Burström A,et al.Cancer associated faecal microbial markers in colorectal cancer detection.Int J Cancer. 2017 Aug 22.

[2] Diamandis E P. Mass spectrometry as a diagnostic and a cancer biomarker discovery tool: opportunities and potential limitations.[J]. Molecular & Cellular Proteomics Mcp, 2004, 3(4):367.

[3] Sawyers C L. The cancer biomarker problem[J]. Nature, 2008, 452(7187):548-552.

[4] Zhang H D, Jiang L H, Sun D W, et al. CircRNA: a novel type of biomarker for cancer.[J]. Breast Cancer, 2018, 25(1):1-7.

[5] Costello E. A metabolomics-based biomarker signature discriminates pancreatic cancer from chronic pancreatitis[J]. Gut, 2018, 67(1):gutjnl-2016-313665.

How many kinds of signaling pathway do you know?

Signal pathway is the phenomenon that the signal transmits a kind of information from the outside of the cell to the inside of the cell when there is a certain reaction in the cell, according to which the cell has to react. The idea of Signal pathway dates back to 1972. But at that time, it was called signal transmission. The concept of signal transduction was widely used by M. Rodbell in a review in 1980.

Do you know Toll and Imd Signaling Pathway?

Inflammation induced by members of the TLR family (except TLR3) goes through a classic signaling pathway. This pathway originated from the Toll/IL-1 receptor homologous region (TIR), which is an intracellular conserved sequence of TLRs. TIR activates intracellular signaling mediators-interleukin-1 receptor-associated protein kinase (IL-1R associated kinase, IRAK) IRAK-1 and IRAK-4, TNFR-associated factor 6 (TRAF-6). Mitogen-activated protein kinase (mitogen activated protein kinase, MAPK and I κ B kinase, I κ K), NF-κ B) induces the expression of inflammatory factors.


The signal molecules involved in this signal transduction include:CD14,MD-2,TRAM,TRIF,TIRAP,MyD88,TLR1,TLR2,TLR3,TLR4,TLR5,TLR6,TLR7,TLR8,TLR9,IRAK-1,IRAK-2,IRAK-4,IRAK-M,TRAF6,TRIAD3A,ST2L,SOCS1,RIG-I,FADD,TOLLIP,RIP1,A20,UEV1A, Ubc13,ECSIT, MEKK-1, TAK1,TBK1, MKK3/6, p38, TAB1/2, MKK4/7, JNK, IKKα, IKKβ, IKKγ, IKKε,NEMO, IκBα, NF-κB, p65/RelA, Casp-8, IRF-3,IRF-7,MAVS and so on.

Do you know NOD-like Receptor Signaling Pathway?

By activating innate and adaptive immunity, microbes initiate a series of defensive processes. The congenital immune system consists of immune and non-immune cells expressed on the sensor or pattern recognition receptor (PRRS) and associated molecular patterns (PAMPS) from different pathogens. PAMPS recognizes inflammatory cytokines and type I interferons that trigger antimicrobial effects through induction. Toll like receptors, NOD receptors, RIG-I receptors and DNA sensors have been well studied. Let’s see what the signaling pathways of NOD receptors look like.

NOD like receptor is widely found in the cytoplasm of human cells whose corresponding ligand can activate NF-K B (NOD1 and NOD2) signaling pathway and activate Caspa se-1 to promote the production of IL-1B and IL-18, thus initiating innate and acquired immunity. NOD protein is the pattern recognition receptor in the plasma and its structure is as follows:

  1. 1.The central nucleotide binding oligodepolymerization region (NACHT) is a common structure of the NLRs family, which is very important for the oligomerization and activation of NLRs.
  2. 2.The N-terminal effect binding region is the domain of the interaction between N-terminal diWhite and protein.
  3. 3.The repeat sequence (LRRs), which is rich in leucine at the C-terminal, can recognize the receptor and the mutations of NOD2 and N-LRP3 in the NOD family can cause inflammation. So at present, the most studied is the NOD-like molecule. NOD1 and NOD2 can recognize different degradation products of bacterial peptidoglycan, and then activate two signal pathways, MAPK and NFBK, by RIP2 kinase (RICK), with the same CARD structure in its CARD oligoset.

Do you know RIG-I-like Receptor Signaling Pathway?

RIG-I is retinoic acid to induce gene protein I (RIG-I). RIG is a cellular receptor that recognizes viral double-stranded RNA and is a member of the RNA helicase family of DexD/H boxes. The C-terminal of RIG-I is a helical domain, which can be combined with synthetic double-stranded RNA and viral double-stranded RNA, and can be solved by ATP enzyme dependent way. The N-terminal is two series of cysteinase recruitment domain (CARD). RIG-I can recognize the RNA component of the virus and transmit signals by its own CARD interacting with the downstream signal molecule MAVS CARD. It activates the transcription factors IRF-3 and NF-κB into the nucleus and induces the expression of interferon B. In order to initiate the innate immune response and regulate the subsequent acquired immune response, it can enhance the ability of the body to resist the virus. In addition, in recent years, two viral RNA recognition proteins, MDA5 and LGP2, have been found to be similar in sequence and function to RIG-I too.

Monoclonal Antibodies—a Valuable Asset in Human History (Part Two)

Abstract: Monoclonal antibody (McAb) was produced by B cell hybridoma cell line. Single antibody monoclonal antibody technology targeting only one antigenic determinant was first initiated in 1975 by Koehler of Germany and Milstein of the United Kingdom. The basic principle of McAb technology is that mouse myeloma cells can proliferate indefinitely and secrete immunoglobulins without antibody activity in vitro and in vivo, while spleen cells of immunized mice have the ability to produce antibodies, but cannot proliferate indefinitely. These two cells are fused into hybridoma cells using a fusion agent (PEG, etc.). Such hybridoma cells have the major features of the parental cells. It can not only proliferate in artificial culture, but also produce specific antibodies. Clones grown from a single cell can be selected by limiting dilution. McAb has many advantages, such as: high unity and homogeneity; high titer; immune antigen does not need to be purified, but pure antibodies can be obtained; different specificities (groups, types, strains) can be obtained; high yield, continuous production, etc. Among these advantages, especially the uniform high specificity, McAb has a very wide practical value, and has formed a very popular emerging industry in the world. Monoclonal antibody technology based on its simplicity Easy, fast, specific, and sensitive Ubiquitous application for disease diagnosis and treatment, food hygiene, etc. The field has broad application prospects.

Keywords: monoclonal antibody, preparation, application, prospects

The development prospect of monoclonal antibodies

Fully humanized mAb

Since the advent of hybridoma technology, monoclonal antibodies have been widely used. However, most of the monoclonal antibodies are of murine origin, and anti-mouse antibodies are produced in vivo during repeated clinical administration, so that the clinical efficacy is weakened or disappeared. Therefore, the ideal monoclonal antibody for clinical application should be of human origin. Therefore, the genes for controlling spleen production in mouse fertilized eggs can be cut off by genetic engineering and gene processing technology, and the human spleen-producing genes in human cells can be extracted and transferred into mouse fertilized eggs to be fertilized. After adult mice, antibodies produced by the spleen in mice are fully humanized antibodies. This technology has good development and application prospects.

High targeting

Monoclonal antibody drug therapy mainly uses its targeting to intervene in various pathways of the development and progression of target cells, or to activate the host’s immunity to tumors. Therefore, the target is the key to study different kinds of antibody drugs. With the continuous development of biomedicine, there will be a more targeted monoclonal antibody and a more powerful “warhead”.

Clinical diagnosis and detection

Monoclonal antibodies are superior to existing antisera in the diagnosis of infectious diseases, immune diseases, endocrine diseases and early pregnancy diagnosis. For example, AIDS has become a major “killer” for human beings. It spreads very quickly and has a certain incubation period in the human body. The patient has no response, which delays the optimal treatment period. For example, HIV is extracted to make a monoclonal antibody, and the monoclonal antibody is made into a card of the same size as the pH test paper. So just put a small card in your mouth and you can detect if you have AIDS. This is a good way to prevent and detect AIDS and to enable patients to receive treatment earlier.

Lifetime immunity

The monoclonal antibody against a certain antigen is introduced into the DNA fragment which controls the synthesis of the corresponding monoclonal antibody by protein engineering technology, and then the corresponding DNA fragment is transferred into the human body by gene therapy technology, but the DNA fragment can be expressed in the body cell and replicated in the human body. Lifetime contains the corresponding antibodies against the corresponding pathogens.

Chimeric antibodies and humanized antibodies are also promising in the field of genetic engineering. If you are interested, please check them out!


[1] Hon-Ming Lam, Xun Xu, Xin Liu et al. Resequencng of 31 wild and cultivated soybean genomes identifies patterns of genetic diversity and selection [J]. Nature Genetics, 2010, 42(1038): 1053-1059

[2] Qingyou Xia, Yiran Guo, Ze Zhang et al. Complete Resequening of 40 Genomes Reveals Domestication Enents and Genes in Silkworm [J]. Science, 2009, 326(5951): 433-436

Math can predict how cancer cells evolve

Applied mathematics can be a powerful tool in helping predict the genesis and evolution of different types of cancers, a study from the University of Waterloo has found.

The study used a form of mathematical analysis called evolutionary dynamics to look at how malignant mutations evolve in both stem and non-stem cells in colorectal and intestinal cancers.

“Using applied math to map out the evolution of cancer has the potential to give oncologists a kind of road map to track the progression of a particular cancer and essentially captures crucial details of the evolution of the disease.” said Mohammad Kohandel, an associate professor of applied mathematics at Waterloo. “Combining the use of applied math with previous research advances in cancer biology, can contribute to a much deeper understanding of this disease on several fronts.”

The study found when cancer stem cells divide and replicate, the new cells that are created can be substantially different from the original cell. This characteristic can have a substantial impact on the progression of cancer in both positive and negative ways and the use of math can help better predict cell behaviour.

The study also concluded that this type of analysis may be useful in preventing the emergence of cancer cells, in addition to helping develop more intense and effective treatments.

“Being able to predict the evolution of cancer cells could be crucial to tailoring treatments that will target them effectively,” said Siv Sivaloganathan, a professor and chair of the department of applied mathematics, at Waterloo. “It may also help avoid the drug-induced resistance known to develop in many cancers.

“In addition to predicting the behaviour of cancer cells, this mathematical framework can also be applied more generally to other areas, including population genetics and ecology.”

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How to Purchase Quality Pet Supplies

The trend in pet supplies, especially pet food, as of 2011 is organic pet food. While in the earlier days, organic food was carried only by health food stores, today even the local grocery stores carry them. Although more expensive than regular pet food, their advantages outweigh their price.

Pet Supplies and Accessories

Organic pet supplies now span even toys, pet beds and grooming products. For instance, you can now find organic cat litter, created from natural and recycled materials. These are good for the environment as well as for the cat. Similarly, there are environment-friendly doghouses that are UV protected, weather treated and ventilated well for your pet’s comfort.

Other poplar supplies include shampoos, flea medications, constraint cable, dog dryers and de-matting brush. While dryers remove water easily out of the dog’s coat, a de-matting brush, compared to an average pet comb or brush, makes grooming easier.

How to Find Quality Pet Supplies Wholesale

Here are some tips to find the best pet supplies:

    • Always buy products from companies that offer few, but high quality products. This is because small companies usually focus on customer satisfaction to retain a steady flow of customers.


    • Start shopping only after making a list of the supplies you need. You can also read customer reviews to take a decision.


    • Another key thing to consider is whether your pet will enjoy the things you buy. While earlier, a bone was a good enough toy, pet owners today splurge on all kinds of pet products. For instance, they largely splurge on fashionable clothing and sweaters. However, pet owners must remember that dogs do not need these, especially if they live in a tropical climate. In fact, these might harm your pet than do any good. This, along with the combined effect of fur overheats their bodies, leading to health problems. So, always consult a vet before purchasing clothing for our dog.


    • Ensure that you never spend more on your pet’s clothing than on its health care needs. Your dog’s health should always be your top priority. So, budget your pet expenses well.


  • As pet foods grow in popularity, so does its price. So, never fall for the temptation of buying the most advertised pet food. Instead, you must check the nutritional facts given on the pack to check the food’s worth. Veterinarians suggest that you replace packaged pet foods with organic food that you can cook at home. So, consult a vet before planning your pet’s new diet.


Wholesale Wedding Shoes Could Be the Answer to Finding Your Bridesmaid Shoes

If you are getting married this summer and have yet to buy shoes for your bridesmaids then why not look into buying a box of whole sale shoes. Buying your bridesmaids shoes off the high street can end up costing you a small fortune and you may struggle to find one pair that is available in everyone’s sizes, this could mean that you need to choose a different shoe or that you need to visit different stores to collect shoes which takes up time that you need to spend finalising your wedding details.

When you purchase wholesale shoes you will be able to purchase one box which has pairs in all sizes so you can be assured that all of your bridesmaids will be wearing the same shoe and no one will look out of place in a set of heels different to the others.

Most wholesale shoes come in boxes of 12 so any pairs that you do not use for your bridesmaids could be sold on an online auction website giving someone else the opportunity to find shoes they like in the sizes they need for their bridesmaids. The shoe sizes range from a 3 to 8 with the most popular sizes having multiple pairs, so you will hopefully have enough pairs in the right sizes for your bridesmaids.

There are many different styles of shoes available for your bridesmaids, you can go for a shoe with a low heel which they should be comfortable wearing all day or you may wish to choose two pairs shoes which will look fabulous on the photographs and shoes which they will be comfortable wearing all day. Don’t ever feel limited to the shoes available in the bridal section, always be sure to take a look at all other shoes as you may just find your perfect shoe for your bridesmaids hidden amongst the sandals. Most of the standard shoes will be available in a variety of colours so finding one to suit the colour of your bridesmaid’s dresses shouldn’t be difficult, the only difficulty you may have is getting all of your bridesmaids to decide on one shoe.

If you can’t find a suitable shoe for yourself then you may want to visit a wholesale shoe website because you can always sell the other bridal shoes in the box you purchase for your own shoes. There are bridal shoes with a low kitten heel which you should be comfortable wearing all day, or you may prefer to choose a higher heel if you are used to wearing them as these may be more comfortable for you.

Many brides and bridesmaids now have two dresses one for the ceremony and one for the reception; if you are having two dresses then you may find it beneficial to have two pairs of shoes. You should look for a pair of shoes which will be comfortable for you to wear during the ceremony and wedding breakfast and then a separate pair of shoes for dancing at the reception.

You should not feel restricted to shopping in bridal stores for your shoes, you need a pair shoes which you like and which you are comfortable in so if that means shopping online, wholesale or on the high street then that is what you should do. Just make sure that you have your shoes enough time before any alterations are made so that your dress is the correct length for the shoes you will be wearing. Your shoes need to be right for you if that means wearing gladiator sandals or stiletto heels, you need to be comfortable on your special day.

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Introductions and Applications of Quantum Dots

Abstract: Quantum dots are semiconductor nanocrystalline materials with quantum confinement effects in three dimensions of space, also known as “artificial atoms.” The particle size of the quantum dot material is generally between 1-10 nm. Since the electrons and holes are quantum confined, the continuous band structure changes to a vertical energy level structure, thereby bringing a narrow luminescence spectrum (20-30 nm), as well as high purity, wide color gamut and other advantages. The origin of quantum dot technology dates back to the mid-1970s. It was originally developed to solve the global energy crisis. In today’s nano research field, quantum dot counting is one of the star materials. Compared with organic fluorescent materials, quantum dots have controllable emission wavelengths and research; high luminous efficiency, one-step excitation, multiple colors, strong fluorescence intensity, long-lasting anti-photobleaching, etc., which is an ideal substitute for organic fluorescent materials. Based on the above characteristics and advantages, the outstanding performance of quantum dots in life sciences and medicine has attracted wide attention. For example, hydrothermal preparation of CdSe quantum dots and their application in cell imaging, based on CdSe/ZnS quantum dots to construct dopamine fluorescence detection method and mitomycin fluorescence detection system, CdSe quantum dot synthesis and the application of heavy metal ion detection, graphene quantum dot preparation technology and the status quo of innovative resources. This paper focuses on the wide application and development prospects of quantum dots.

Keywords: quantum dots, CdSe/ZnS, fluorescence detection, development and application

The concept of quantum dots and its classification


Quantum dots are stable, water-soluble semiconductor nanoparticles composed of Group II-VI or Group III-V elements.


Quantum dots are composed of a core and a shell. The core generally uses CdX (X=S, Se, Te) as a material, and the shell portion is composed of other materials with different band gaps or a vacuum medium. Studies have shown that quantum dots can be prominent in biochemistry such as labeled peptide chains and deoxyribonucleotide long-chain polymers, which has attracted widespread attention from biologists, chemists, and physicists. Because its research direction involves many interdisciplinary subjects such as physics, chemistry, biomedicine, etc., quantum dots have considerable development and application prospects.

The application of quantum dots in the field of life science

Traditional fluorescent probes are a far cry from quantum dots as fluorescent probes. Because quantum dots have the advantages of wide laser spectrum, continuous distribution, and symmetric emission spectrum distribution, narrow width and rich color, quantum dots can solve many problems that traditional fluorescent probes cannot solve. However, the coupling problem that occurs with quantum dots of different materials is still the main problem that currently limits the development of quantum dots. Scientists predict that if the coupling problem of quantum dots of different materials is solved, the researcher can combine quantum dots as fluorescent probes with specific antibodies, and the fluorescent probes will be specific to different specific organelles in the cell. After sexual combination, different organelles are distinguished. Since a variety of semiconductor nanocrystals of different sizes can change according to the change of size, a series of marking systems with different wavelengths and different colors are produced, and the fluorescence intensity, high stability and durability make the semiconductor nanocrystals can withstand multiple times. Excited and maintained in the original state, it is convenient for the researcher’s long-term experimental observation, and the optical characteristics will not change significantly.

Fluorescence Resonance Energy Transfer (FRET) is a spectral analysis method that analyzes non-radiative energy transfer between fluorescent substances. Since its introduction, FRET has been widely used in various fields of agriculture, medicine, forensic science and scientific research. . In recent years, FRET technology has greatly improved in spatial resolution and sensitivity. Sensors designed according to FRET have been widely used in biological research fields, such as detecting conformational changes of biological macromolecules and interactions between biological macromolecules and the distance between biomolecules on the nanometer scale. Studies have shown that the optical properties of the energy donor and the assembly method of the sensor have a crucial impact on the detection performance of the FRET sensor. However, the traditional energy supply receptors (such as organic fluorescent dyes, biological materials, lanthanides, etc.) are fluorescent. Low intensity, low light stability, sensitive to the environment, poor biocompatibility, and high toxicity, easily affected by autofluorescence and stray light in the living body, resulting in the degradation of fluorescence intensity and the failure of biological detection to achieve the desired target. This limits the development and application of FRET sensors.

The FRET system in the near-infrared region has been constructed. The donor has a fluorescence emission peak at the near-infraredInP/ZnS quantum dot, and the acceptor is a near-infrared fluorescent dye Cy7. Make up for the shortcomings of traditional visible quantum dots in biological applications. At the same time, the concentration and cell microenvironment pH sensitivity of the system were tested. The results show that the fluorescence intensity of the FRET system can directly reflect the pH change of the cell microenvironment, and has high detection accuracy for the pH value of the system.

By studying the effect of different pH solutions on the FRET system, the results show that the Cy7 dye itself is not sensitive to pH. The sensitivity of the FRET system to pH is mainly due to the sensitivity of the quantum dots to pH, when the pH of the solution is at From 7 to 10 hours, the FRET system has a high FRET transfer efficiency. The cell test results show that the fluorescence signal of the FRET probe changes significantly with the change of the pH of the extracellular fluid, and can be used for detecting cancer cells in the biological microenvironment. At the same time, the obvious fluorescence signal of the FRET system in the extracellular fluid of breast cancer can be applied to the imaging of cancer cells, achieving the dual function of the FRET system.

This study provides a theoretical and experimental basis for the application of the FRET system as a sensitive probe for early diagnosis of cancer.

The application of quantum dots in medical drugs (taking CdSe and ZnS as examples)

Since quantum dots of different sizes can produce different mark colors, scientists can combine quantum dots of different sizes with different target cells to detect target cells for drug action, thereby screening drugs; it is known that centimeter-thickness of tissue, infrared rays can be Easy to penetrate and visible light can’t. Therefore, it is possible to mark the tissue with quantum dots that emit light in the infrared region, and perform medical diagnosis under the excitation of infrared light by the same detection principle as medical imaging. CdSeQDs is a kind of quantum dot which is relatively mature in research. Compared with other kinds of quantum dots, CdSeQDs has significant advantages. For example, under the same wavelength of light, the emission spectrum of CdSeQDs is 430 with different particle size. Adjustable in the range of -660nm, CdSeQDs has high fluorescence quantum yield, easy detection, mild synthesis conditions and short synthesis cycle. Therefore,CdSe quantum dots have long been widely concerned and studied.

Synthesis method of CdSeQDs

The morphology and structure of semiconductor quantum dots have a great influence on their inherent magnetic, electrical and optical properties. The properties of QDs prepared by different synthetic methods are different and their uses are different. Therefore, the synthesis of quantum dots has been subject to scientists’ wide attention. At present, organic phase synthesis and aqueous phase synthesis are two main synthetic methods. Organic phase synthesis of QDs is one of the most commonly used methods. Its development mainly includes two stages: organic metal method using organic metal as reaction precursor and green chemical method using inorganic metal as reaction precursor. The organometallic method can synthesize QDs which are monodisperse and have high stability, and the QDs prepared by this method have better fluorescence quantum yield and optical properties. However, the organometallic method also has many disadvantages, such as the use of raw materials is relatively expensive and has greater toxicity, the synthesis process is dangerous, prone to explosion, etc., which limits the further promotion and application of this method. Later, the researchers proposed a green chemical synthesis method, using high stability, low toxicity and low cost cadmium oxide as raw material instead of dimethyl cadmium as a precursor, mixed with Se solution to prepare CdSeQDs with excellent properties. Although this method reduces the reaction cost, the use of a more toxic organic phosphine solvent is retained during the reaction, so a greener synthesis method needs to be sought. The preparation of QDs by aqueous phase method overcomes the shortcomings of organic synthesis, but the method also has problems such as imperfect crystals, many surface defects and poor luminescence properties, so the aqueous phase synthesis method needs further improvement.

Surface functionalization of CdSeQDs

Although CdSeQDs have many unique and excellent physicochemical properties and optical properties, they also have some limitations, such as low biocompatibility, poor water solubility, and relatively high toxicity. In order to overcome these shortcomings, the surface of quantum dots needs to be encapsulated and modified. In recent years, various small molecules (including sulfur, polymer, DNA and other modifiers) have been reported to encapsulate modified CdSeQDs. The prepared QDs have good biocompatibility and are widely used in the detection of biological small molecules, disease diagnosis and treatment, biosensing, etc., and have broad application prospects in the field of biomedicine.

Protein package

Protein-encapsulated QDs have many important applications in the biomedical field, so proteins are used as a common encapsulant for the synthesis of QDs. Proteins can usually be modified to the surface of QDs by electrostatic attraction, covalent bond coupling, etc., where covalent bonding is the most common method. Covalent bond bonding is a combination of a functional group of a protein molecule and a functional group on the surface of a quantum dot to form a covalent bond. Since the protein has an amino group and a sulfhydryl group, it is easy to form a covalent bond with the amino group and the carboxyl group-modified QDs. The use of novel proteins (natural phytochelatins) bound to poorly water-soluble CdSe/ZnSQDs increases the water solubility of QDs, and the encapsulated QDs exhibit high colloidal stability and remain in aqueous solution, including its high quantum yield, capable of bioconjugation with different functional groups.

The following figure is a schematic diagram of fluorescence resonance energy transfer caused by self-assembly of GCN-mCherry and glutathione-coated CdSe/ZnS quantum dots.

Antibody package

An antibody is a glycoprotein capable of specifically binding an antigen. Attaching an antibody to a quantum dot enables specific binding of an antibody on the QDs to an antigen in the living body, thereby enabling qualitative and quantitative detection of biomolecules in the living body. When a disease occurs in an organ in a living body, it causes overexpression or decreased expression of certain molecules in the organ; therefore, antibody-modified QDs can detect tumor cells as fluorescence sensors in vivo. The binding method of antibody and quantum dot is divided into non-covalent binding and covalent binding, and non-covalent binding mostly adopts biotin-avidin linkage. Covalently bound to the surface functional group of the antibody and the quantum dot reacts with each other by the activation of dimethylaminopropyl and ethylcarbodiimide hydrochloride to form a covalent bond. The most commonly used combination is amino and carboxyl. The most commonly used combination is an amino group and a carboxyl group, an amino group and a thiol group, and an aldehyde group and a hydrazide.


Peptide wrap and DNA wrap

Peptides are often used to modify QDs as common biomolecules. The combination of peptides and quantum dots often utilizes the amino and sulfhydryl groups on the surface of the peptide to covalently bond with the amino and carboxyl groups on the surface of the quantum dot. In addition, the method of synthesizing small molecule-encapsulated QDs by biomimetic method is relatively simple and has been widely promoted. Usually, phospholipids are also used to wrap QDs.

DNA-functionalized QDs play an important role in biological applications. Single-stranded DNA recognizes complementary DNA/RNAs that form a normal helical structure through base-pair pairing, so DNA-functionalized QDs can detect viruses and bacteria. DNA fragments as well as small RNAs, DNA can also act as aptamers with high affinity to target molecules. These aptamer-functionalized quantum dots can be used to detect ions, proteins, or for disease diagnosis and cell imaging.

Construction of mitomycin fluorescence detection system based on CdSe/ZnS quantum dots

In the development of the past few decades, experts have studied the optimal reaction conditions of quantum dots in detail, and developed a new method for detecting mitomycin in biological fluid based on the fluorescence properties of CdSe/ZnS quantum dots. The intensity has a good linear relationship with the concentration of mitomycin. Under the optimal experimental conditions, the CdSe/ZnS quantum dots interacted with mitomycin, and the fluorescence intensity of the quantum dots was quenched with the increase of mitomycin concentration. The quenching mechanism causes photo-induced electron transfer to cause quantum dot fluorescence quenching. The detection method is simple in operation, high in sensitivity, and has good applicability to analysis of actual samples. In addition, based on CdSe/ZnS quantum dots, the study of dopamine fluorescence detection methods can be constructed, and corresponding results have been obtained.


Application of quantum dots in fingerprint visualization

In 2000, MENZEL in the United States reported for the first time the use of CdS quantum dots for the fingerprinting of cans on the surface of cans, creating a precedent for the application of quantum dots as a new material in fingerprint visualization. Subsequently, MENZEL et al. used PAMAM (polyamide) as a template to control the growth of CdS quantum dots encapsulated in dendrimers by the spatial threshold effect of dendrimers. The synthesized CdS/PAMAM polymer was diluted with methanol as solvent. After that, it was successfully used for the appearance of latent fingerprints on aluminum foil and polyethylene samples. They believe that functional groups such as amino or carboxyl groups on the surface of CdS/PAMAM can interact with fingerprint residues to deposit CdS/PAMAM onto the fingerprint lines, and the fingerprints appear through the fluorescence of CdS/PAMAM polymer under ultraviolet light. The method can be used for the identification of surface fingerprints of various objects (such as transparent tape, black plastic bags, tin foil, etc.) of different background colors.

The above is a comparison of fingerprint effects with CdS/PAMAM polymer and traditional visualization reagents. As you can see, the fingerprints displayed with CdS/PAMAM polymers are clearer(The picture on the left is CdS/PAMAM).

Application of quantum dots in improving solar cells

Solar cells, as the name implies, are devices that make full use of the energy of sunlight and convert solar energy into electrical energy through the photoelectric effect. Ordinary solar cells cannot fully utilize solar energy, and heat loss during conversion is large, resulting in defects in low photoelectric efficiency conversion rate. Scientists have used silicon semiconductor materials as a medium for solar and electrical energy conversion to develop common semiconductor materials for solar cells. After the silicon semiconductor material is irradiated by the sun, the internal electrons move freely to form a current. It is this special property of semiconductor materials that semiconductor solar cells can operate normally, but the results in actual production are not satisfactory. Scientists have learned that currents are generated only when these free electrons are moved to the electrodes. In fact, there are few free electrons moving to the electrodes, resulting in low conversion to solar energy. Therefore, ordinary semiconductor materials cannot completely convert solar energy into electrical energy.

Scientists envisaged that if the theory of quantum mechanics was introduced into the solar cells of ordinary semiconductor materials, it would be able to make up for the shortcomings of the actual power generation efficiency of ordinary semiconductor materials. Scientists conducted a large number of theoretical calculations, and the results were quite shocking to the people present. This kind of battery material is not only cheaper, but also can make full use of the sunlight energy while the consumption in the conversion process is minimal, so that the conversion rate of the solar cell to the photoelectric is doubled. Although the current super battery is still under development, whether it is as good as scientists expected and when it will be released to the public is still unknown. However, it is undeniable that quantum dot solar cells are becoming a new trend in research and development and are currently the most concerned research topic. It is believed that this super battery can completely solve the shortcomings of high energy consumption and low photoelectric conversion efficiency of ordinary semiconductor materials. Quantum dot solar cells will show excellent skills and bright prospects in future solar energy conversion and utilization.

Quantum dot sensitized solar cells are one of the quantum dot solar cells that have been developed so far. A quantum dot sensitized battery is a battery between a common semiconductor material solar cell and a super cell (quantum dot solar cell). So quantum dot sensitized cells cannot be called true quantum dot solar cells, it is just a transitional product. Quantum point solar cells in the true sense are still in the research and development stage. Quantum dot solar cells need to be studied in the way of photoelectric conversion, and the selection of medium is also necessary. The medium is the focus and hot spot of research on super batteries. The dielectric materials of super batteries must have ultra-high conversion rate and low cost, quantum dots. There is still a long way to go before solar energy research and development. As a transition product, quantum dot sensitized solar cells are based on dye-sensitized solar cells (DSSC) and are designed and developed using similar working principles. The quantum dot sensitized solar cell photoanode is composed of a quantum dot attachment and a photogenerated electron injection carrier, and the carrier is mainly composed of a binary semiconductor oxide.

The development prospect of quantum dots

As a new research field, quantum dots have attracted the attention of scientists in many fields in a short time. Scientists are actively involved in the study of quantum dots, which further demonstrates that the study of quantum dots is related to the advancement of science and technology and the development of science. Quantum dot technology is still in the early stage of theory, and scientists have found that quantum dots play an important role in life sciences and medicine. Scientists envision that if we can fully apply quantum dots to our lives, our lives will be more convenient and better. This is a perfect flaw for scientists and everyone. Scientists are fully devoted to the study of quantum dots, trying to put the application of quantum dots from theory to life and put them into practice. Quantum dot technology is a high-tech. Scientists have discovered the outstanding performance of quantum dots as fluorescent probes, the application of quantum dots in medical drugs, and the application of quantum dots in improving solar cells. Quantum dots are A little bit infiltrated into our lives. The research of quantum dots is still in its infancy. With the advancement of society and the continuous development of science and technology, the research scope of quantum dots is gradually expanding. As a new concept, quantum dots are well known. There are more mysteries in semiconductor microcrystals waiting for us to explore and discover. The study of quantum dots is moving at a strong pace, and the application of quantum dots is showing bright prospects.

Functional Overexpression and Purification of Membrane Transport Protein

One of the basic characteristics of living cells is the ability to exchange substances and information with the external environment. Through the physiological activities of material and information exchange, cells can sense environmental changes, acquire nutrients necessary for metabolism, and discharge metabolites and waste. The selective absorption and discharge of solutes is mainly achieved by a membrane transport protein-based transport system on the cell membrane.

What are transport proteins?

Transport proteins are a large class of membrane proteins that mediate chemicals and signals exchange inside and outside biofilms. The lipid bilayer forms a hydrophobic barrier around the cell or organelle that isolates it from the surrounding environment. Although some small molecules can penetrate directly through the membrane, most hydrophilic compounds (such as sugars, amino acids, ions, drugs, etc.) require the help of specific transporters to pass through the hydrophobic barrier. Therefore, transporters play an important role in a wide range of cellular activities such as nutrient uptake, release of metabolites, and signal transduction.

The isolation and purification of proteins are the basis for the study of the structure and function of proteins. Under normal circumstances, the expression of most membrane proteins is extremely low, and the bottleneck of membrane protein structure and function research is the lack of effective expression of membrane proteins. Purification techniques are effective means of conducting structural studies. Compared with other types of membrane proteins, membrane transporters are basically single-gene coding products, which can independently perform physiological functions and become a good functional expression and purification research object. The currently used purification methods are: (1) using molecular biology techniques to construct a recombinant membrane protein containing a fusion affinity tag; (2) optimizing the functional expression of the recombinant membrane protein; (3) and isolating and purifying the expressed Membrane protein, and activity testing and structural studies. The advantage of this strategy is that, on the one hand, the introduction of the fusion affinity tag facilitates the detection and purification of the recombinant membrane protein; on the other hand, it is easy to modify and manipulate the target protein, and these modifications and operations such as site-directed mutagenesis can provides important information for the study of protein structure and function.

Construction of recombinant membrane transport protein

When constructing a recombinant membrane protein for in vivo expression, the topological structure of the protein must be considered, especially whether the N-terminus and C-terminus of the expressed membrane protein are located on the cytoplasmic side or the outside of the cell. On the one side, heterologous overexpression of membrane transporter is affected by the N-terminal sequence of the first transmembrane helix located outside the lipid membrane. When constructing a recombinant membrane transporter, whether to introduce a signal sequence-promoting protein based on the position of the N-terminus of the membrane protein expression. In the construction of its expression vector, especially when it is necessary to introduce an affinity tag at the N-terminus, it is necessary to simultaneously introduce and contain a signal sequence in order to successfully express the target protein. Other side, depending on the topological structure of the membrane transporter and the polarity of the amino acid side chain, the type and position of the affinity tag to be introduced can be selected. The affinity tag is an amino acid polypeptide or protein, and an affinity tag is introduced into the recombinant protein. The purpose is to determine whether the target protein is expressed and affinity-purified the target protein. The common feature of the affinity tag is that it can bind to a certain affinity medium, thereby facilitating the affinity purification of the recombinant protein containing the affinity tag. Affinity labeling needs to follow the principle of positively charged amino acid inward, otherwise the expression of the target protein containing the affinity tag will be affected.

Functional overexpression of recombinant membrane proteins

According to the topological properties of membrane proteins, we need to select appropriate expression strategies and optimize expression conditions to obtain a large number of active membrane proteins, which facilitates subsequent purification and structural function studies. Factors that limit membrane protein expression include: lacking of efficient membrane protein folding mechanism or stabilization mechanism in the expression host; degradation of protease; toxicity of recombinant membrane protein to host; inefficiency of protein translation caused by codon preference; post-translational processing of protein Modified or missing modifiers.

Depending on the source of the membrane protein expressed, alternative efficient expression systems include living expression systems such as prokaryotic expression systems and eukaryotic expression systems; and expression systems in vivo. For membrane proteins derived from prokaryotes, the E. coli expression system has achieved good results. The expression and folding of most membrane proteins of Gram-positive bacteria such as E.coli are related to signal recognition particles (SRP). At the same time, inserting into the membrane under the action of SRP completes the folding. The optimization of the functional expression of the recombinant membrane protein aims to control the relative speed of translation and folding to achieve the optimal expression of membrane protein. SRP-mediated membrane protein folding. It also relates to the recognition and folding efficiency of heterologous recombinant membrane protein by the host cell folding mechanism. Therefore, it is necessary to optimize the factors affecting membrane protein translation and folding, for example, the homology of the expression host and heterologous membrane protein source, culture temperature, the composition of the medium, and the choice of co-expressed protein, etc.

Functional expression of membrane proteins derived from eukaryotes often involves a series of processes in protein processing and sorting, and prokaryotic expression systems often fail to achieve satisfactory results. The use of weak protein promoters and the simultaneous expression of molecular chaperones can increase the efficiency of ion channel protein expression. These studies demonstrate that membrane proteins require a certain amount of time and appropriate mechanisms for processing and folding, and ultimately localization, after being synthesized by ribosomes. This is important for the functional expression of membrane proteins. In the living expression system, many factors can lead to the inefficiency of membrane protein expression, for example, the expressed membrane transporter has toxic effects on host cells. In this case, the expression of membrane transporter can be considered by using the in vitro expression system.

In vitro expression systems can also cost-effectively label target proteins for specific studies. The membrane proteins expressed in vitro exist in agglomerated state. After the detergent is added, most of the membrane proteins can be dissolved. The CD structure shows that the secondary structure is mainly α-helix, and the dissolved EmrE, SugE and TehA can be recombined. On the artificial lipid membrane. The transport activity of EmrE recombinant membrane proteoliposome showed that the in vitro expressed EmrE has transport activity. The detergent has two polarities and is stable to the stability of the membrane protein in the membrane-free state. If a suitable detergent is directly added to the in vitro expression system, a membrane transporter present in a dissolved state can be obtained. These membrane proteins can be directly used to construct recombinant membrane proteoliposomes. Studies on MscL recombinant membrane proteoliposomes showed that MscL expressed in vitro after addition of detergent has similar activity to MscL expressed in vitro. Therefore, the membrane transports protein with suitable conformation and functional activity can be obtained by using the in vitro expression system.

Selection of detergents and purification of recombinant membrane proteins

Purification of recombinant membrane proteins containing fusion affinity tags involves three major steps: releasing of membrane proteins from the plasma membrane with a suitable detergent; adsorption of free membrane proteins with affinity chromatography or affinity media; washing away impurities and elution membrane protein. The choice of detergent in this process must consider the following two points: (1) the solubilizing efficiency of the detergent on the target membrane protein; (2) how to remove the detergent after purification for structural and functional studies. Membrane proteins require a plasma membrane to support their structure and function in their natural state, but how to maintain the stability of membrane protein structure and function under the condition of membrane removal during separation and purification is important. Usually, the detergent interacts with the membrane protein and the hydrophobic part of the membrane lipid to weaken the hydrophobic binding between the membrane protein and the membrane lipid molecule, and release the membrane protein from the membrane lipid. The hydrophobic portion of the free membrane protein retains its original conformation under the protection of the detergent, thereby maintaining its original function, such as binding to substrates or inhibitors. Detergents are divided into ionic and nonionic types. Non-ionic detergents and amphoteric detergents have a weaker denaturation effect on membrane proteins, and are commonly used for ion exchange and affinity chromatography of membrane proteins. The solubilizing efficiency of the detergent on the membrane protein is related to the structure of the detergent and the critical micelle concentration (CMC), which can be optimized by changing the type and concentration of the detergent. The appropriate detergent will contain the affinity label. After the recombinant membrane protein is dissolved from the plasma membrane, the affinity membrane is adsorbed by the affinity chromatography column or the affinity medium to carry out the affinity purification experiment. The purification step is similar to the affinity purification step of the soluble protein. However, it must be noted that the concentration of the detergent in the solution must be kept above the critical micelle concentration, while the solution is required to contain high concentrations of glycerol (20%) to maintain the hydrophobic conformation and functional stability of the membrane protein.

In the state of membrane removal, even with the synergistic effect of detergent and glycerin, the stability of most membrane proteins is not strong. Therefore, after purification, membrane proteins must be recombined into artificial lipid membranes as needed to construct membrane protein liposomes, and restore the structure and function of membrane proteins on lipid membranes. In this process, the concentration of detergent should be reduced below its critical micelle concentration, so that the membrane protein is detached from the detergent and inserted into the lipid membrane to form artificial membrane proteoliposome. Methods for removing the scale or reducing the concentration of the detergent include a dilution method, a gel filtration method, a dialysis method, an ion exchange chromatography method, and a special medium absorption method. When using gel filtration and ion exchange chromatography, it is not conducive to the membrane protein interaction with membrane lipid molecules while removing detergent. Dialysis removes detergents at a slower rate and is commonly used for two-dimensional crystallization experiments of membrane proteins. When constructing artificial membrane proteoliposome for functional activity studies, descaling is usually removed by dilution or Biobeads absorption. The use of detergents with high critical micelle concentration facilitates the rapid removal of detergents from the system, so the detergent is exchanged while the membrane protein is affinity purified, and the detergent with low critical micelle concentration is exchanged high. Critical micelle concentration of detergent.

A Detailed Introduction for Oligopeptide Synthesis

A classification of polypeptides, generally having a molecular weight range of less than 1000 Daltons, also known as small peptides, oligopeptides, oligopeptides, or small molecule active peptides, generally composed of 2- to 6 amino acids, more than A polypeptide called a polypeptide and having more than 50 amino acids is called a protein. The difference with other peptides is that they can be directly absorbed in the human body without digestion. Oligopeptides can be further divided into: oligopeptide-1, oligopeptide-3, oligopeptide-5 and the like, and oligopeptide-6 is also called hexapeptide or hexapeptide.


Absorption theory

The traditional theory of protein digestion and absorption believes that the protein is in the intestinal lumen and is formed by peptide protease and chymotrypsin to form free amino acids and oligopeptides (containing 2 to 6 amino acid residues). The oligopeptide is completely hydrolyzed by peptidase. It becomes a free amino acid and enters the blood circulation as a free amino acid. According to this theory, protein provides amino acids only to the animal’s body, that is, the nutrition of the protein is the nutrition of the amino acid. Therefore, as long as we provide the animals with sufficient essential amino acids, the animals will be able to obtain satisfactory performance. However, many studies have shown that the amount of proproteins that can be replaced by monomeric amino acids is limited. Feeding low levels of protein to livestock and supplementing synthetic amino acid diets does not yield optimal performance and feed efficiency. To achieve both of these goals, the diet must have the lowest amount of proprotein and oligopeptide.


Transport mechanismThe intact peptide enters the epithelial cells, and the presence of absorption pathways within the cell is neglected for a considerable period of time. The possibility of peptide transport was mentioned more than 100 years ago (Matthews, 1987). Agar (1953) confirmed the transport of intact di-glycans across the intestinal epithelium of rats. However, due to the influence of traditional protein digestion and absorption theory, scholars are not easy to accept other absorption methods, and because the diglyceride is considered to be a special dipeptide, its molecular weight is small, so the importance of this discovery. Not recognized. It was not until the 1960s that Newey and Smyth (1959, 1960) provided information on the complete absorption of peptides for the first time. They found out. The digestion products of proteins in the small intestine not only have amino acids, but also a large number of oligopeptides, and the peptides can enter the intestinal mucosal cells intact and further hydrolyze in the mucosal cells to form amino acids into the blood circulation.


Later, between 1965 and 1980, more and more evidence was accumulated about the intestinal transport of intact short peptides. In particular, David M. Matthews of London and Siamak A of Pittsburgh, Adibi’s team confirmed that the possibility of peptide transport is not only academically meaningful, but may represent an absorption pathway for amino acid nitrogen uptake that is as important as the corresponding free amino acid uptake. . The absorption process of amino acids and peptides by the intestinal mucosa is complicated. It is generally believed that dipeptides and tripeptides are absorbed into intestinal cells and then hydrolyzed by peptidases into the blood circulation in the form of free amino acids. Nutritional physiology and pharmacological tests have confirmed that in some cases intact peptides can enter the circulation through the peptide carrier of the intestinal mucosa.


Although the transport mechanism of oligopeptides is not fully understood, three can be confirmed: 1. The pH-dependent H+/Na+ exchange transport system does not consume adenosine triphosphate (ATP); 2. The active process depends on the concentration of H+ or Ca2+. , to consume ATP; 3, glutathione (GSH) operating system. Although the mechanism of animal oligopeptide transport is not fully understood, the transport of oligopeptides requires the recognition of vectors, and some mammalian small peptide vector genes have been cloned. By studying the structure and function of oligopeptide carriers, revealing the relationship between the carrier and oligopeptides and related ions, it is a hotspot in the research of oligopeptide transport mechanism. Many new scientific and technological achievements, such as enzymatic peptides, have been obtained in this respect. Bioactive peptides are based on food protein macromolecules containing high-quality protein, and are spliced ??and modified into the most active oligopeptides between macromolecular proteins and amino acids by using enzymes (enzyme scissors). Molecular active polypeptide, which has the characteristics of small molecular weight, easy absorption, and high nutritional value.


Absorption characteristics1. Do not need to digest, directly absorbed.2. No need to consume human energy when absorbing.3. Will not increase the burden of human gastrointestinal function.4. It has the characteristics of preferential absorption.5. Promote the body’s absorption with its own energy.6. Force the body to absorb when the body’s absorption function is lost.7. 100% is absorbed by the body.8. Fast absorption. It is 129,600 seconds faster than the body’s absorption of macromolecular proteins and 64,800 seconds faster than human amino acids.9. With a carrier role. Other nutrients for human consumption can be carried on the body and transported to human cells and tissues.10. Become a means of transportation in the human body and transport various trace elements to various parts of the human body.11. Has a strong diversity of activities and physiological functions.


Application fieldAccording to experts, oligopeptides with low molecular weight can have higher skin permeability than peptides, and are more easily absorbed by human skin. At the same time, due to the small molecular weight, biological activity has a qualitative leap. The smaller the molecular weight of the peptide, the shorter the “amino acid chain” and the easier it is to be absorbed and utilized by the body.

Expert analysis, due to OCO’s unique biological personality and outstanding functional performance, it has a huge application space in the field of daily cosmetics, shampoo and hair care, food and health products, biomedicine, and even textiles. Oligopeptides are widely used in the beauty field, leading the new trend of healthy skin care in China’s high-end beauty market.


About us

Creative Peptides is specialized in the process development and the manufacturing of bioactive peptides. We are dedicated to offering custom peptide synthesis, process development, GMP manufacturing as well as catalog products for customers in industry and research are some our products like: Peptide Modification,De novo Peptide Design,Long Peptides Synthesis,Peptide Drug Discovery,etc.

Several Structural Functions of Viral Genome

The virus is the simplest organism. The complete virus particles include the coat protein and the internal genomic DNA or RNA (some coat proteins outside the coat have an envelope composed of host cells containing the glycoprotein encoded by the viral gene. The virus cannot replicate independently, it must enter the host cell to make the virus replicate by means of some enzymes and organelles in the cell. The function of the coat protein (or envelope) is to recognize and invade specific host cells and protect the viral genome from nucleases Destruction.

Structural features

  1. The size of the virus genomeis quite different. Compared with bacteria or eukaryotic cells, the genome of the virus is very small, but the genomes of different viruses are also very different. For example, hepatitis B virus DNA is only 3 kb in size and contains less information. It can only encode 4 proteins. The genome of poxvirus is 300 kb, which can encode hundreds of proteins, not only for the enzymes involved in viral replication. Even the enzymes for nucleotide metabolism are encoded, so the poxvirus is much less dependent on the host than the hepatitis B virus.
  2. The viral genome may consist of DNA or RNA. Each virus particle contains only one nucleic acid, or DNA or RNA, and the two generally do not coexist in the same virus particle. The DNA and RNA constituting the viral genome may be single-stranded or double-stranded, and may be a closed-loop molecule or a linear molecule. For example, papillomavirus is a closed-loop double-stranded DNA virus, while the genome of adenovirus is linear double-stranded DNA, poliovirus is a single-stranded RNA virus, and the genome of reovirus is double-stranded. RNA molecule. In general, most DNA viruses have genomic double-stranded DNA molecules, while most RNA viruses have single-stranded RNA molecules.
  3. The genome of most RNA viruses is composed of continuous ribonucleic acid strands, but some genomic RNAs of viruses are composed of discrete nucleic acid strands. The genomic RNA molecules of influenza viruses are segmental and consist of eight RNA molecules. Each RNA molecule contains information encoding a protein molecule; the reovirus genome consists of a double-stranded segmental RNA molecule with a total of 10 double-stranded RNA fragments, each of which encodes a protein. At present, no viral genome composed of segmental DNA molecules has been found.
  4. Gene overlap means that the same DNA fragment can encode two or even three protein molecules. This phenomenon is only found in mitochondria and plasmid DNA in other biological cells, so it can also be considered as a structural feature of the viral genome. This structure enables smaller genomes to carry more genetic information. The overlapping genes were discovered by Sanger in 1977 when studying ΦX174. ΦX174 is a single-stranded DNA virus, the host is Escherichia coli, and therefore, it is a phage. It infects E. coli and synthesizes 11 protein molecules with a total molecular weight of about 250,000, which is equivalent to the amount of information contained in 6078 nucleotides. The viral DNA itself has only 5375 nucleotides, which can encode a protein molecule with a total molecular weight of 200,000. Sanger can’t solve this contradiction for a long time before clarifying that some of the 11 genes of ΦX174 overlap. There are several cases of overlapping genes:

(1) One gene is completely inside another gene. For example, genes A and B are two different genes, and B is contained in gene A. Similarly, gene E is within gene D.

(2) Partial overlap. For example, gene K overlaps with a part of genes A and C.

(3) Only one base overlap of the two genes. For example, the last base of the stop codon of gene D is the first base of the J gene start codon (such as TAATG). Although these overlapping genes are mostly identical in their DNA, the protein molecules produced are often different because the reading frame is different when the mRNA is translated into a protein. Some overlapping genes have the same reading frame, but the starting sites are different. For example, in the SV40 DNA genome, there are 122 base overlaps between the three coat proteins VP1, VP2 and VP3, but the codons are not identical. While the small t antigens are completely within the large T antigen gene, they have a common start codon.

  1. Most of the viral genome is used to encode proteins, only a very small one is not translated, which is different from the redundancy of eukaryotic DNA. For example, the part that is not translated in ΦX174 only accounts for 217/5375. G4DNA accounts for 282/5577, less than 5%. The untranslated DNA sequence is usually a control sequence for gene expression. For example, the sequence between the H gene and the A gene of ΦX174 (3906-3973), a total of 67 bases, includes a control region for gene expression such as an RNA polymerase binding site, a transcription termination signal, and a ribosome binding site. Papillomavirus is a type of virus that infects humans and animals. The genome is about 8.0Kb, and the untranslated part is about 1.0kb. This region is also a regulatory region for other gene expression.
  2. Genes of functionally related proteins or genes of rRNA in viral genomic DNA sequences tend to cluster at one or several specific sites in the genome to form a functional unit or transcription unit. They can be transcribed together into a molecule containing multiple mRNAs, called polycistronie mRNA, which is then processed into template mRNA for various proteins. For example, the late gene encoding the adenovirus encodes 12 coat proteins of the virus. When the late gene is transcribed, it generates a polycistronic mRNA under the action of a promoter, and then processes it into various mRNAs, which encode various coat proteins of the virus. Functionally related; the DEJFGH gene in the ΦX174 genome is also transcribed in the same mRNA and then translated into various proteins, of which J, F, G and H are all coding for coat proteins, assembly of D proteins and viruses. Relatedly, the E protein is responsible for the lysis of bacteria, which are also functionally related.
  3. Except for retroviruses, all viral genomes are haploid, and each gene appears only once in the viral particle. There are two copies of the retroviral genome.
  4. The gene of bacteriophage (bacterial virus) is continuous; while the gene of eukaryotic virus is discontinuous, with introns, except for positive-strand RNA viruses, the genes of eukaryotic viruses are first transcribed into mRNA. The precursor is processed to remove the intron into mature mRNA. More interestingly, some eukaryotic introns or parts of them are introns for one gene and exons for another. This is the case with early genes such as SV40 and polyomavirus. The early genes of SV40, namely the big T and small t antigen genes, were all counterclockwise from 5146, the large T antigen gene was terminated to 2676, and the small t antigen was terminated to 4624, but from 4900 to 4555. A 346 bp fragment is an intron of the large T antigen gene, and the DNA sequence from 4900-4624 in the intron is a small t antigen encoding gene. Similarly, in polyomaviruses, the introns in the large T antigen gene are the genes encoding the T and t antigens.

Bovine papillomavirus genome structure and function

Papillomavirus is a DNA virus that infects human and animal skin, mucous membranes and causes papilloma lesions. It belongs to the papovavirus family. It can be divided into bovine papillomavirus (BPV), human papillomavirus (HPV), etc. depending on the host infected with the virus. The papillomavirus genomes that have been discovered so far have similar structures. The genomic structure and function of papillomavirus are illustrated by BPV as an example. The BPV DNA is 7945 bp in length and is a closed-loop supercoiled structure, which can bind to histones to form nucleosomes in host cells. The first base G of the single HpaI restriction site in the BPV DNA is the 1st position, and the base number is located in the direction of 5’→3′. DNA sequence analysis showed that all open reading frames (ORFs) existed on one DNA strand, and the genes overlap each other. The entire BPV gene component is a coding region and a non-coding region (NCR), and the coding region is divided into an early transcriptional functional region (E region) and a late transcription functional region (L region) according to the function of the encoded protein. 1. The non-coding region (NCR) non-coding region, also known as the upstream regulatory region (URR) or the long control region (LCR), is located between the late gene L1 stop codon and the first gene E6 first start codon, and the length is Different in different papilloma viruses, it is about 1.0 kb in BPV. In the promoter sequence of NCR transcription, transcription and expression of early genes can be initiated. In addition, there are enhancer sequences in this region, which can be activated by the early gene product E2 protein, further promoting the expression of early gene AAC, which has been clarified. The sequence of the enhancer of the BPVNCR region, which is a palindrome of TTGGCGGNNG and ATCGGTGCACCGAT. It can be seen from the structural characteristics of NCR that its main function is to regulate the expression of BPV gene.

  1. Early transcriptional functional region (or early gene region, E region) The E region of BPV contains eight open reading frames (ORFs), namely E6, E7, E8, E1, E2, E3, E4, E5, of which E6, E7 and E1 genes partially overlap, E8 is completely in E1, E3 and E4 are all contained in E2, and E5 and E2 partially overlap. The protein product encoded by the E2ORF can bind to the enhancer of NCR to increase or decrease the expression level of the early gene.

In addition, the E2ORF synergizes with the E1ORF to maintain the free state of the papillomavirus DNA without integration into the host cell chromosome. The proteins encoded by E6 and E7ORFs may be oncogenic proteins. E6 and E7 proteins can cause malignant transformation of the host into tumor cells. The mechanism of cell transformation induced by E6 and E7 proteins is not clear at this stage, but there are two explanations. [1] The Cys-xx-Cys repeat sequence was found in the amino acid sequence of the E6 and E7 proteins, and the structure is considered to be a specific structure possessed by the intracellular nucleic acid binding protein, and thus the E6 and E7 proteins are considered to be DNA-binding proteins. It can regulate the activity of genes, further affect the proliferation and differentiation of host cells, and make the process uncontrolled to form tumors. [2] Recently, two proteins with molecular weights of 53KD and 106KD were found in normal cells, respectively, called p53 and p106. protein. The loss or inactivation of these two proteins often causes cell malignancy. The study found that the E7 and E6 proteins of papillomavirus can be inactivated by binding to p53 and p106 proteins, respectively, which may also be a mechanism by which E6 and E7 proteins cause cell malignancy.

  1. Late transcriptional domain (late gene region, L region): There are two L-region ORFs, L1 and L2 ORF, which encode the coat protein of papillomavirus, in which L1 protein is the major coat protein and L2 protein is the minor coat protein.

Genomic structure and function of RNA phage

The most well-studied E. coli RNA phage are MS2, R17, f2 and Qβ. Their genomes are small, ranging from 3,600 to 4,200 nucleotides, and contain four genes. MS2.R17 and f2 have almost the same genomic structure. Two of the four genes encode structural proteins of phage: one is the gene of protein A, which is 1178 nucleotides in length. The function of protein A (called a mature protein) is to enable the phage to recognize the host and allow its RNA genome to enter the host bacterium, and each phage typically has only the protein A of the molecule. Another structural protein gene is 399 nucleotides in length and encodes a coat protein to form a viral particle, each of which has 180 molecules. The rest of the genome encodes an RNA replicase and a lytic protein. The gene encoding the lytic protein partially overlaps the coat protein and the replicase gene, but the reading frame is different from the reading frame of the coat protein. There are many secondary structures in the MS2, R17, and f2 genomes, and self-pairing of bases in RNA molecules may have a role in preventing RNase degradation. In addition, there is a non-translated sequence at the 5′ and 3′ ends of the coding gene, which also has a role in stabilizing RNA molecules. The genome of another RNA phage Qβ is slightly larger than the genome of the above RNA phage; [1] there is no independent lytic protein gene, but the structural protein A2 (or mature protein, Maturation Protein) has the function of dissolving protein. [2] also encodes another coat protein A1.

Structural features and functions of the hepatitis B virus genome

The genomic DNA structure of hepatitis B virus (HBV) is very peculiar and is a circular partial double helix structure with a length of about 3.2 kb. Two-thirds of them are double-helix and 1/3 are single-chain, which means that the two chains in DNA are not equal in length. The 5′ end of the long chain is not covalently linked to the 3′ end, but is covalently linked to a protein. The 5′ end of the long chain is complementary to 250-300 base pairs. The long chain is a negative chain and the short chain is a positive chain. The length of the short chain varies from virus to virus and is generally about 1.6-2.8 kb long, about 2/3 of the long chain. The gap between the short strands can be filled by a DNA polymerase in the viral particle. Hepatitis B virus is currently known as the smallest double-stranded DNA virus that infects humans. In order to replicate independently in cells, the virus contains as much genetic information as possible in a small genome. Therefore, the genomic structure of HBV appears to be particularly precise and concentrated, making full use of its genetic material.

There are many overlapping gene sequences, and there are four open reading frames in the HBV genome, which encode the nucleocapsid (C) and envelope (S) proteins of the virus, viral replicase (polymerase) and a seemingly virus Gene expression related to protein X. The two small ORFs in front of the S gene belong to the same reading frame as the S gene ORF. The ORFS can be read through and encode two S protein-associated antigens. These two antigens are also present on the surface of the virus particles. They are called pre-S1 (pre-S1) and pre-S2 (pre-S2), respectively. Similarly, there is a short ORF in front of theORF, called pre-C (pre-C), which encodes a larger C-protein associated antigen. All of these ORFs are on the negative strand DNA (long chain), in which the S gene is completely overlapped with the polymerase gene, the X gene overlaps with the polymerase gene and the C gene, and the C gene overlaps with the polymerase. Recently, Miller et al. found two ORFs, ORF-5 and ORF-6, in the HBV genome. These two ORFs overlap with the X gene, and ORF6 is not encoded by negative strand DNA, but is encoded by positive strand DNA. The function of these two ORFs is currently unclear.

The regulatory sequence is located inside the gene, which is also a way for HBV to save on the use of genetic material. Sequences involved in HBV group replication are: short-chain forward replication sequences (DR1 and DR2) and U5-like sequences (named for similar faces to the U5 sequence at the end of the retrovirus). DR1 and U5 are located in the pre-CORF and are the starting site for the long chain of synthetic DNA. DR2 is located at the overlap of the polymerase gene and the X gene and is the starting site for DNA short-chain synthesis.

There are four signal sequences involved in HBV gene expression: [1] promoter, [2] enhancer, [3] polyA additional signal, [4] glucocorticoid sensitive factor (GRE). Since the genes in the HBV genome are transcribed on the three HBV mRNA transcripts, respectively, there should be at least three RNA polymerase II promoters at the proximal 5′ end of each transcript in the viral genome, although these promoters The gene sequences are not known, but these promoters are apparently present within the encoded protein sequence. The enhancer (ENH) is located in the polymerase gene; the polyA additional signal is located in the CORF; and the GRE is located in the SORF and polymerase genes. GRE is a DNA fragment of a hormone receptor structure that, when combined, increases the level of transcription of a known gene.

GRE has many enhancer features: [1] is a factor that acts as a cis, [2] acts in both directions of transcription, [3] can function at different distances from the genes it regulates.

It can be seen from the above that the HBV genome is structurally strict and tissue efficient, and is rare in known viruses. HBVDNA not only has its unique structure, but its DNA replication process is also very special. When HBV DNA enters the host cell, it first becomes a complete closed-loop double-stranded DNA, and the negative strand is used as a template to synthesize a full-length “+” strand RNA (called pre-genomic RNA). The “+” strand RNA is packaged in immature core-like particles, and a DNA polymerase and a protein are also packaged in the particles. In the granule, the “+” strand RNA is used as a template to catalyze the synthesis of “-” strand DNA by reverse transcriptase. The specific mechanism is unclear, and may be similar to the replication of adenoviral DNA, because at the 5′ end of the “-” strand DNA. There are also proteins that are covalently bound. The synthesis of “+” strand DNA is polymerized and extended with the negative strand DNA as a template and a piece of RNA as a primer, and the core-like virus particles also become mature virus particles in the process. At this time, the positive strand DNA is still not synthesized, resulting in different lengths of the two DNA strands of the viral genome.

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