China Wuhan Desheng Biochemical Technology Co., Ltd Company News

  Operation process of Hanks virus transportation medium: （1） Accurate weighing of reagents: select appropriate culture medium according to different fungi and uses, and the reagents required for the culture medium must be pure.   （2） Correction of pH value: put various components of the weighed culture medium into the container, mark and draw lines, heat and dissolve, supplement water, and determine the pH value. It is usually measured by a precision test paper or pH meter with pH of 6.8-8.0. Use 1N NaOH and 1N HCl to adjust the pH value to a suitable range.   （3） Filtration: put the glass funnel on the iron frame, then use gauze with cotton or filter paper to put it in the funnel, pour the above medium into it and filter until it is transparent.   （4） Subpackage: subpackage the filtered culture medium into the medium test tube or triangle bottle (5ml for each tube; 100ml to 150ml for each triangle bottle), pack the cotton plug and wrap it with kraft paper for sterilization.   （5） Sterilization: medium sterilization, commonly used high-pressure steam sterilization. Generally, the nutritional cells of microorganisms are killed when they are boiled in water, but the spores of bacteria have strong heat resistance, so they must be sterilized by high pressure steam to achieve the goal of thorough sterilization. According to the principle that the steam temperature increases with the pressure, that is, the higher the pressure, the higher the steam temperature. Therefore, under the same temperature, high pressure steam sterilization is better than dry heat sterilization. Moreover, in the case of damp heat, the protein is easy to coagulate and denature after the bacteria absorbs water, because the steam has strong penetration and good sterilization effect.   Hanks virus transportation medium     Attention 1. Samples of Hanks virus transportation medium should be detected when they are fresh. In case of bacterial contamination, the bacteria may contain endogenous HRP, and may also produce false positive reaction. If stored for a long time, it can polymerize in ELISA to deepen the background. 2. After the frozen sample is dissolved, the protein is partially concentrated and unevenly distributed. It should be fully mixed, gently and slowly, to avoid bubbles. It can be mixed upside down, and it should not be strongly shaken on the mixer.   3. Turbid or precipitated samples should be centrifuged or filtered first, and then tested after clarification.   Repeated freezing and thawing will reduce the titer of the protein, so if the sample to be tested needs to be preserved for multiple tests, it should be stored in a small amount of sub packed ice. There are some reasons for the straightness of the standard curve in ELISA: whether the preparation of the standard curve is improper, whether the hole washing part is sufficient, whether the reading is inaccurate or whether there is suction error. Find the reason and find the solution.   Storage conditions Due to the different raw materials and requirements, the storage of the medium is slightly different. The general culture medium is easy to be polluted or decomposed by bacteria after being heated and hygroscopic. Therefore, the general culture medium must be kept in a damp proof, dark and cool place. For some culture media (such as tissue culture media) that need strict sterilization, they must be stored in a refrigerator of 2~6℃ for a long time. Because the liquid culture medium is not easy to keep for a long time, it has been transformed into powder.   The Hanks virus transportation medium independently R&D by Desheng has been successfully put on the market, and customers in need are welcome to inquire for details.

  Buffer is a type of substance that maintains the pH of the reaction system, usually composed of weak acids, weak bases and their salts or amphoteric substances, such as CO2 in photosynthesis, bicarbonate in human plasma, etc. are substances with buffering capacity, which is necessary for cellular metabolic reactions. In the field of biochemical detection, the most commonly used are Tris buffer and phosphate buffer, and there are certain differences between the two.   1. Buffer range   The buffering range of Tris buffer is 5.0~9.2, there are differences according to different acids of Tris. Commonly used pH in biochemical tests are 6.8, 7.4, 8.0, 8.8. Tris buffers are used more and more in biochemical research, and there is a tendency to exceed phosphate buffers. For example, Tris buffers have been used in SDS-polyacrylamide gel electrophoresis, and phosphates are rarely used.   The buffer range of phosphate PBS buffer is 1~12, adjusted according to the ratio of different phosphate acid salts. Phosphate is one of the most traditional and extensive buffers in biochemistry. Phosphoric acid has two acid salts. They are second-order dissociation and have two dissociation constants. Therefore, the pH range of the buffers they make is very wide. Generally, potassium salt is better than sodium salt, and its solubility is high. SDS-polyacrylamide gel electrophoresis buffer can not use potassium salt, potassium salt of SDS will precipitate.   2. Application areas   Tris is a tromethamine as an amino buffer base that does not contain sodium. It does not bring sodium and potassium ions into the system and does not affect the osmotic pressure. It can also be added with saline to adjust the salt balance if necessary. It has little effect on the biochemical process, and it does not form precipitates with calcium, enzymes and heavy metal ions, and does not affect the activities of kinases, phosphatases, dehydrogenases and other enzymes. Usually used for DNA, RNA and protein related experiments, commonly used buffer systems are: Tris-HCl buffer, TBS buffer, TE buffer, TAE buffer, TBE buffer, Tris glycine buffer, Tris phosphate buffer, etc. It should be noted that the pH value of Tris is greatly affected by temperature, and it is necessary to control the temperature; the Tris solution is alkaline, it will absorb CO2, and pay attention to sealing.   Although phosphate buffers have a wider buffering range, the buffering capacity above pH 7.5 is smaller. Tris itself is better when it is alkaline. Phosphate itself can dissociate cations and has a salt balance effect, which will not break the organism. Protein structure and biological characteristics, phosphate PBS buffer is usually used for cell experiments. However, precipitation with calcium, magnesium ions and heavy metal ions will also inhibit the activity of certain enzymes.   Nowadays, the application of Tris buffer is more and more, there is a tendency to exceed phosphate buffer, Desheng Technology is also focusing on the development of Tris buffer related applications. However, it is recommended that you select the best biological buffer according to the reagent requirements of the experiment.

Trimethylolaminomethane Tris, namely aminobutriol, also known as bradycardic acid amine, is a kind of ternary alcohol containing amino group, which has weak alkalinity. It is usually used with weak acid as Good’s buffer and widely used in biochemical detection and kits in biochemistry and molecular biology.   Good's buffer Tris powder   Physical and chemical properties of Tris English name: Trometamol Molecular weight: 121.135 Molecular formula: (HOCH2)3CNH2 Appearance: white crystal powder Solubility: soluble in water and ethanol, slightly soluble in ethyl acetate and benzene, insoluble in ether and carbon tetrachloride. pKa: 8.1 at room temperature, pH10.5 in aqueous solution Buffer range: 7.0~9.2 Tris buffer is usually used as a solvent for nucleic acids and proteins. Because the carbon atom at position 2 of Tris is connected with amino group, and the aqueous solution is alkaline, when DNA dissolves in this solution, it will be deprotonated, so as to improve the solubility. As a buffer, Tris is usually used with weak acid, such as hydrochloric acid or Tris HCl salt. In addition to HCl, it is often used with acetic acid and boric acid, as well as glycine in electrophoresis buffer.   Tris HCl buffer Weigh the required mass according to the molecular weight of Tris (commonly used concentration is 1~2M), prepare an aqueous solution, and then slowly add concentrated hydrochloric acid to adjust to the required pH value. Note that when the prepared solution is alkaline, it will absorb the acid gas CO2 in the air, and the bottle cap needs to be closed tightly; when adjusting the pH, the solution needs to be cooled to room temperature, and the solution is sensitive to temperature. When the pH value is increased by 1℃, the pH value will drop by 0.03, otherwise, it will change when it is cooled to room temperature after adjusting the pH value.   TE buffer Tris EDTA buffer, commonly used in molecular biological reagents, dissolves DNA. The commonly used concentration is 10-100mM, and the molar concentration of EDTA is one tenth of it. Hydrochloric acid regulates the pH to the required value. TAE buffer: TrisAcetateEDTA, where acetic acid is used instead of hydrochloric acid. TBE buffer: Tris+Borate+EDTA, adjust pH and replace hydrochloric acid with boric acid. Tris-Gly buffer: adjust pH and replace hydrochloric acid with glycine. TBS buffer: In addition to Tris base, salt NaCl and a small amount of KCl should be added to the solution, and the pH should be adjusted with concentrated hydrochloric acid TBST buffer: add 0.1% Tween 20 to TBS.   Besides being used as DNA, protein lysis buffer, electrophoretic buffer and SDS-PAGE gel electrophoresis, Tris can also react with carbonic acid as humic acid amine in body fluid, generate bicarbonate, absorb hydrogen ions and correct acidemia, and have strong action and can penetrate cell membrane. Tris produced by Desheng is mainly used for Good’s buffer and mass export for further refining.

  PEP, namely phosphoenolpyruvate, is a very important substance in all life activities. It participates in many biochemical processes such as cell respiration and photosynthesis. The reagent we produce refers to its salt, phosphoenolpyruvate tricyclohexamine salt reagent.   Physical and chemical properties of PEP salt English name: Phosphoenolpyruvic acid tricyclohexylammonium salt Molecular weight: 465.56 Molecular formula: C21H44N306P Molecular structure   Application of serum carbon dioxide determination kit In the chloroplast, PEP can absorb carbon dioxide and convert it to oxaloacetate under the catalytic action of PEP carboxylase (carboxykinase). This process is the core of photosynthesis. The efficiency of PEP carboxylase to fix CO2 is very high, and the reaction is very sensitive. With this feature, the content of trace carbon dioxide in serum can be determined, and the activity of PEP carboxylase in plant samples or serum or plasma can also be measured.                                                                CO2 fixation process of PEP in photosynthesis   Determination principle PEP and bicarbonate (the form of serum CO2) are catalyzed by enzyme to produce oxaloacetate. Oxaloacetate and NADH are catalyzed by malate dehydrogenase MDH to produce malate malate. NADH (nicotinamide) is measured with a spectrophotometer The reduced state of adenine dinucleotide, reduced coenzyme I) The absorbance at 340nm is attenuated, and the amount of attenuation is proportional to the concentration of CO2, thereby measuring the serum CO2 content. Similarly, the enzyme activity can be measured according to the rate of change of absorbance when a certain amount of CO2 is generated, that is, a reagent kit for measuring the activity of a sample PEP carboxylase.   PEP is used in cell protectants and antioxidants In cellular respiration, PEP participates in the last step of glycolysis, which is converted to pyruvate after removing high-energy phosphate groups. In the process of organ tissue refrigeration, it can reduce the oxidative stress and ATP consumption of tissue cells, reduce organ damage, and prolong the preservation time of clinical organs.   The use of PEP salt is not limited to this. Due to its carbon dioxide absorption and cell glycolysis characteristics, many applications are still under development. Desheng Technology's mature reagent is PEP tricyclohexylamine salt, mainly used Kit for carbon dioxide determination and PEP carboxylase activity determination.

Phosphoenolpyruvate (PEP) is a glycolysis intermediate. Phosphoric acid is a glycolysis metabolite with a high-energy phosphate group. After dephosphorylation, PEP is converted to pyruvate, which can penetrate cell membranes With cell protection and antioxidant activity, it can be used as a cell protection agent and antioxidant in the liver of cold-preserved mice and a potential organ protection agent.   Its cell protection effect is mainly reflected in the following aspects 1. PEP (0.1-10 mM) significantly attenuated the hydrogen peroxide-induced reduction in cell viability in HeLa cells in a dose-dependent manner. 2. PEP also inhibited the decrease of calcein-acetylmethoxy-stained cells and the increase of propidium iodide-stained cells induced by hydrogen peroxide. The increase of intracellular reactive oxygen species stimulated by hydrogen peroxide was significantly reduced. 3. Evaluation by electron paramagnetic resonance method also shows the potential of PEP to scavenge hydroxyl radicals. 4. In addition, PEP has the potential to scavenge 1,1-diphenyl-2-pyridylmethylhydrazonyl radical (a representative artificial free radical), although the potential is small. 5. PEP (10 mM) slightly inhibited the reduction of H2O2-induced cellular ATP content, but did not show any effect at low doses (0.1, 1 mM). 6. PEP (0.1-10 mM) also reduced cell damage, but did not attenuate the decrease in intracellular ATP content induced by the glycolysis inhibitor 2-deoxy-D-glucose.   These results indicate that PEP exerts a cytoprotective effect and has antioxidant potential, although the exact cytoprotective mechanism has not been fully elucidated. However, we believe that PEP is a functional carbohydrate metabolite with cell protection and antioxidant activity, and may be used as a therapeutic agent against diseases involving oxidative stress.   In addition, the PEP produced by Desheng company can also be used to determine the content of CO2 in the biochemical kit. The content of CO2 reflects the metabolic acid-base balance in the body. It can also be used for the auxiliary diagnosis of diseases such as pyloric obstruction, Cushing's syndrome, taking too many alkaline drugs and respiratory acidosis.

HEPES is a kind of hydrogen ion amphoteric buffer with good buffer ability and long time to maintain pH constant. It is widely used in nucleic acid reaction buffer, hybridization buffer and cell culture medium. According to its characteristics, there are some differences in the configuration of buffer in different experiments.   Physical and chemical properties of HEPES 2-[4-(2-Hydroxyethyl)-1-piperazinyl]ethanesulfonic acid CAS No.: 7365-45-9 Molecular formula: C8H18N2O4S Molecular weight: 238.3 Buffer range: 6.8-8.2 Molecular Structure: HEPES mother liquor (buffer stock): directly prepare 0.5-1m HEPES solution and NaOH solution, control the mixing ratio of the two to adjust the pH, and then use distilled water or ultra pure water to fix the volume. If necessary, NaOH can be replaced by KOH. HEPES buffer salt solution: add a small amount of sodium chloride and disodium hydrogen phosphate into HEPES solution, then add NaOH aqueous solution, adjust pH, add distilled water for constant volume, and store at low temperature.   HEPES cell culture medium: add a small amount of sodium chloride, potassium chloride, disodium hydrogen phosphate, dextran, etc. into HEPES aqueous solution, then adjust the pH with NaOH solution, and finally store at a constant volume and low temperature. In cell adhesion experiments, calcium and magnesium ions are usually added to HEPES culture medium to protect the cadherin of cells and not affect the formation of cell aggregation.   HA solution: HEPES-BSA cell culture medium, which is one of the components of cell culture medium, does not contain calcium and magnesium ions, and contains some other salt ions. After the treatment of filtration bacteria, it is mostly suitable for cleaning and culture in primary culture of tissue cells.   The above is the application difference of HEPES buffer developed and produced by Desheng in different experiments. In addition, the non inactivated virus preservation solution newly developed by the company also contains HEPES buffer. Because it has no toxic effect on cells, it not only maintains pH, but also increases the in vitro survival time of virus host cells after sampling, retains the integrity of virus nucleic acid and protein to the greatest extent, and improves the detection accuracy.

The biological buffer solution is used to stabilize the pH value in biochemical experiments. The full name of MOPS is 3-morpholinepropanesulfonic acid, and the full name of MES is 2-morpholineethanesulfonic acid. Both of them are buffers that are often used in our biological experiments and play a very important role in the experiment. What is the difference between them? What do we need to pay attention to during use? The following is a brief analysis:   MOPS Buffer, or 3-morpholinepropanesulfonic acid buffer, is a widely used and very important buffer. MOPS itself belongs to Good's buffer, and the buffer range is between 6.5 and 7.9. It is suitable for the electron transfer and phosphorylation research of chloroplast thin layer preparation. Protein purification chromatography buffer. In addition, MOPS is also used in biochemical diagnostic kits, such as DNA/RNA extraction kits, PCR kits, and kits for measuring creatinine.   MES Buffer, that is, 2-morpholineethanesulfonic acid, biological buffer, buffer range 5.5–6.7, pKa value of MES buffer is close to physiological pH, used in active aminogel chromatography column to separate mobile phase components of brain tubulin ; MES can not be absorbed when passing through the cell membrane, and can penetrate ultraviolet light, such biological buffers are commonly used in plant cell culture.   Precautions for MOPS 1. MOPS biological buffer reagent is a zwitterionic buffer. If the dosage of MOPS is very small each time, it is generally used after proper packaging. 2. Normally, the biological buffer can easily change the color of the liquid to yellow after encountering light, and the light yellow can be used. If the color is too dark, it should not be used again. 3. The use of MOPS biological buffer reagents requires special attention. The production safety and personnel health must not be sloppy, so the experimental clothes should be worn and wearing disposable gloves to operate. Once the solution splashes into the eyes, or comes into contact with it, it must be rinsed with plenty of water immediately, and immediately go to the hospital.   To sum up, when choosing a buffer, not only according to the required buffer range and buffering capacity of the buffer solution, but also according to the specific experimental content. In addition, in biological experiments, we must pay attention to the sterilization of the used containers, water and other additives, so as not to bring other influencing factors to the experiment. The Good ’s buffers independently developed and produced by our company have always been trusted by customers, welcom enterprises and individuals to call for further consultation.

MOPS, or 3-(N-morpholine) propane sulfonic acid, with CAS1132-61-2, is a kind of N-substituted amino sulfonic acid on morpholine amino group, which is usually used as amphoteric ion buffer with excellent performance, and also a buffer with very wide application and huge demand in good's buffer. It has a high water solubility and a buffer range of 6.5-7.9.   Physical and chemical properties of MOPS English Name: 3-morpholinopropanesulfonic acid Molecular formula: C7H15NO4S Molecular weight: 209.26 Melting point: 277-282℃ Structural formula: Different from the traditional weak acid salt buffer, MOPS does not participate in or interfere with the biochemical reaction process, does not denature or affect the enzyme activity, and does not inhibit the enzyme chemical reaction. Therefore, it can be used for the research of organelles and easily denatured, pH sensitive proteins and enzymes.       Configuration of MOPS buffer (1) Weigh 41.8g of MOPS and dissolve in about 700ml of deionized water or DEPC treated water according to the experimental requirements; (2) Use 2 M NaOH to adjust the pH value to 7.0; (3) Add 1 M NaOAc 20mL and 0.5M EDTA (pH8.0) 20 mL treated by DEPC to the solution; (4) Fix the volume to 1L, use 0.45um filter membrane to remove impurities, and store in dark at room temperature. If sodium ion is to be removed in the experiment, KOH is used instead of NaOH, and accurate pH value is required. PH measurement can be used, and the proportion of mops solution and sodium hydroxide can be adjusted to adjust pH.   Application examples of MOPS RNA was used to extract MOPS from 1% agarose modified gel. Melted DEPC water, MOPS and agarose, then used microwave oven, then placed it at room temperature for 60℃, then added 37% formaldehyde.   In addition, MOPS can also be used as buffer in Northern blot hybridization of RNA separation and membrane transfer, electrophoresis buffer in protein purification, forced medium components of bacteria, yeast and animal cells, DNA extraction and PCR diagnostic kit buffer. Desheng has rich experience in the R&D and production of mops and other biological buffers, and is committed to serving IVD related enterprises at home and abroad.

The chromogenic substrate ADOS is a raw material used for chromogenic in the biochemical kit, with CAS No.82692-96-4, which can be oxidized with 4-AAP by hydrogen peroxide in the presence of peroxidase to produce chromogenic reaction, which is sensitive, rapid detection. Here is a guide for using the ADOS reagent produced by our company for reference only.   Appearance and packaging of ADOS The packaging is a foam insulation box, containing blue ice or ice packs. The product manual and test report are included. If it is not complete, please call customer service to request an electronic version. Packed in dark brown bottles, the reagent is white crystal powder, if the color is deepened, it may have grown bacteria or partially oxidized and cannot be used.   After receiving the goods, will the product deteriorate if the built-in ice pack has melted? This product is stable at room temperature. Low temperature transportation is to prevent extreme temperature conditions that may occur during transportation. Therefore, when you receive the product, if the ice pack has been melted, it will not affect its quality, please feel free to use. If it needs to be stored for a long time, it is recommended to store it in freezing and dark. If it has been prepared into a solution, it is recommended to use it immediately to avoid oxidation and discoloration in contact with air.   Configuration of ADOS solution The chromogenic substrate ADOS is a highly water-soluble aniline sodium salt derivative improved on the basis of traditional chromogen phenol and aniline. Reagent powder may adhere to the wall of the tube or bottle, allowing centrifuges to be centrifuged at low speed to reduce product loss; the product has good solubility and can be directly dissolved in deionized water; double-distilled water or super Pure water; when special circumstances require DMSO as a solvent, first check its solubility in DMSO, and set the corresponding DMSO concentration control group; in special cases, use water bath or ultrasonic vibration to assist dissolution; the concentration changes too quickly during the dilution process It can be reconstituted by ultrasound.   The product is sterile or not This product is a powder reagent. It is frozen and preserved, which reduces the possibility of bacteria growth of solution reagent. When preparing the solution, only keep the operating environment and equipment sterile. If strict sterilization is needed, it is recommended to use a bacterial filter instead of high temperature and high pressure sterilization.   When ADOS is used as a chromogenic substrate to participate in the hydrogen peroxide coupling chromogenic reaction, it requires the participation of peroxidase. Therefore, the pH of the reaction system is strict. It is recommended to use a biological buffer produced by Desheng Technology to adjust the reaction; Environmental pH ensures enzyme activity and improves detection sensitivity.  

α-glucosidase (EC.3.2.1.20), that is, α-D-glucoside glucose hydrolase, also known as glucosyltransferase GTase, its uses are very wide, including food and fermentation industry, chemical industry and medical applications, is a very promising enzyme preparation.   Enzymatic properties Glucosidase is widely present in animals, plants, bacteria and fungi, as long as it has carbohydrates as an energy source and has organisms with cell structures. There are two types of hydrolytic enzymes because the glucosidic bonds are classified into α-type and β-type. Among them, the hydrolysis of α-glucosidase can cut the α-1,4 glycosidic bond from the non-reducing ends of α-glucoside, oligosaccharides and dextran to release glucose; Glucose residues are transferred to another glucose or maltose substrate with α-1,6 glycosidic bonds, thereby obtaining non-fermentable isomaltose IMO.   The physiological significance of enzymes α-glucosidase can hydrolyze oligosaccharides such as maltose and sucrose in the small intestine into glucose, and participate in regulating glucose metabolism and fat production in the body. In animal cells, α-glucosidase catalyzes the hydrolysis of glycogen to glucose in the lysosome, and participates in the metabolism of glycogen (glycogen is a branched polysaccharide formed by the combination of glucose and is a glucose in animal cells Main storage situation, glycogen is hydrolyzed first when hungry, followed by fat).     Application of enzyme preparation 1. Because of its key role in the metabolism of sugar in animal cells, recombinant human acid α-glucosidase is usually used to treat Pompe disease. 2. Used in the synthesis of functional oligosaccharides, using the transglycoside activity of α-glucosidase to synthesize energy oligoglucans, oligomalto-oligosaccharides, oligomeric isomaltose, oligo-cellulose oligosaccharides, etc. Functional sugars as prebiotics. 3. α-glucosidase can be used to screen active natural drugs. It can be seen that α-glucosidase is a very important enzyme involved in sugar metabolism in organisms, and its enzyme activity is also an important indicator for body detection and disease diagnosis. To this end, Desheng Technology is also constantly exploring and innovating in the application of enzyme preparations.

The chromogenic substrate DAOS is a sodium sulfonate derivative containing aniline group, with CAS No 83777-30-4, which belongs to a very sensitive chromogenic reagent and is widely used in various biochemical reagents in biochemical kit, here is a brief introduction to its application in the low-density lipoprotein detection series of blood lipid detection.   In the blood, cholesterol is usually in the form of lipoprotein bound to apolipoprotein in a complex, which is divided into four types: high-density lipoprotein HDL, low-density lipoprotein LDL, very low-density lipoprotein VLDL and chylomicrons, of which LDL It is involved in transporting cholesterol to peripheral cells, and HDL is responsible for absorbing cholesterol from cells. At present, the detection of low-density lipoprotein is mainly to first monitor the total cholesterol content, high-density lipoprotein content and triglyceride content to calculate the LDL concentration. LDL-C=TC-HDL-C-TG/2.2(in mmol/L), (2) LDL-C=TC-HDL-C-TG/5(in mg/dl). In the detection of total cholesterol, cholesterol ester is first hydrolyzed to cholesterol and fatty acid by cholesterol esterase CHE, and then it is oxidized to 4-cholesterenone by cholesterol oxidase to generate hydrogen peroxide, which is then coupled with DAOS and 4-AAP to generate chromogenic reaction with hydrogen peroxide under the catalysis of POD. The concentration of total cholesterol can be determined by measuring the absorbance.   In the detection of triglycerides, triglycerides are hydrolyzed to glycerol and fatty acids in the presence of LPL; glycerol and ATP generate glycerol-3-phosphate and ADP under the catalysis of GK; glycerol-3-phosphate and oxygen generate dihydroxyacetone phosphate and hydrogen peroxide under the catalysis of GPO, and then coupled with 4-APP with chromogenic substrate as in the above steps Hydrogen peroxide produces chromogenic reaction and TG concentration is measured.   In the detection of HDL, double reagent is used. The first reagent contains polyanion and surfactant, selectively combines with VLDL and LDL, and inhibits COD in the second reagent. CEH plays a role in VLDH-CH and LDH-CH, thus selectively acts on HDL-CH. through CEH-COD-POD, the concentration of HDL can be determined by measuring the absorbance. Finally, the LDL concentration can be obtained by calculation.   In a word, the chromogenic reagent DAOS is mainly used to generate chromogenic reaction with hydrogen peroxide generated after a series of enzyme catalytic reactions with the target to be tested. In addition, kits produced by some company use ESPAS and ADPS as chromogenic substrate. This series developed by Desheng has other chromogenic substrates, which can be used for different biochemical tests according to their characteristics.

Viruses are a kind of microorganisms closely related to our human health. They are invisible to bacteria and fungi, but from the most common cold viruses to the dreaded HIV and new coronaviruses, the research on viruses is extremely urgent and important. Since the virus is a non-cellular organism, it must be parasitized in living cells, and the virus transportation media is needed after leaving the cell after sampling.   The virus transportation media we are talking about here is mainly for the extraction and detection of the nucleic acid of the virus. The integrity of the virus or the virus nucleic acid is preserved within a certain period of time, and then sent to the testing center to test whether the sample contains virus to diagnose whether the test object is infected. The virus transportation media is divided into inactivated type and activated type, and its components are also different. The following describes their main components and their key roles.   Inactivated virus transportation media: 1.High concentration of guanidine salt can not only quickly destroy the cell membrane of the virus host cell, but also denature the protein, make the virus protein denature and precipitate, so that the nucleic acid can get rid of the protein entanglement. Extract nucleic acid DNA or RNA, and can inhibit nuclease. Since only viral nucleic acid is used for detection, this type of sampling tube can be stored at low temperature for one week after sampling. 2. EDTA and Tris mainly use the characteristics of EDTA to complex metal ions such as calcium, magnesium and iron to prevent metal ions from activating proteases and reduce the impact on nucleic acid quality. 3. RNAse inhibitors are mainly aimed at RNA viruses. Nucleic acids are better preserved than active viruses, but will degrade quickly in the presence of ribonuclease.   Activated virus transportation media: 1. Hanks solution is mainly made of various inorganic salts, buffers, glucose, 0.4% phenol red under sterilization conditions, consistent with the pH value, osmotic pressure and sterile conditions of the cell growth state, so that the virus host cells Survival time is extended. 2. Gentamicin and fungal antibiotics are antibacterial and antifungal, respectively. 3. BSA (V) bovine serum protein stabilizes the virus protein shell and forms a protective film to make it difficult to decompose. 4. HEPES buffer and a variety of amino acids to maintain the virus adapt to pH and increase its survival time. 5. Cryoprotectant to maintain the stability and integrity of the virus when the temperature is too low.   The components of the virus transportation media of different manufacturers may be slightly different. The above is a reference provided by Desheng’s products. Some businesses may be suspected of excessive publicity. This type of virus transportation media is used for nucleic acid detection or antibody detection of virus samples. It is recommended that the user should test as soon as possible after sampling or store in strict low temperature to ensure that the test is accurate.