Enzyme-linked immunosorbent assay ELISA kit (enzyme-linked immunosorbent assay referred to as ELISA) is a new type of immunoassay technology developed on the basis of immunoenzymatic techniques (immunoenzymatic techniques), has now been successfully applied to a variety of pathogenic microorganisms Immunological diagnosis of infectious diseases, parasitic diseases and non-infectious diseases caused. It has also been applied to the quantitative determination of large molecule antigens and small molecule antigens. The ELISA method is sensitive, specific, simple, fast, stable and easy to automate. It is not only suitable for the examination of clinical specimens, but also because it can check hundreds or even thousands of specimens within a day, so it is also suitable for serum epidemics. Investigation. This method can be used not only to measure antibodies, but also to measure circulating antigens in body fluids, so it is also a good method for early diagnosis.
The application scope of ELISA in various fields of biomedicine can be summarized in four aspects: 1. Immunoenzyme staining the positioning of various intracellular components. 2. Study the synthesis of anti-enzyme antibodies. 3. A trace of immunoprecipitation reaction appears. 4. Quantitative detection of antigen or antibody components in body fluids.
The ELISA process includes an antigen (antibody) ELISA kit adsorbed on a solid support called a coating, plus the test antibody (antigen), plus the corresponding enzyme-labeled antibody (antigen) to generate the antigen (antibody)-the test antibody ( Antigen)-Enzyme-labeled antibody complex, which then reacts with the enzyme's substrate to produce a colored product. The amount of antibody (antigen) is calculated by means of the light absorption of the spectrophotometer. The quantification of the antibody (antigen) to be tested is proportional to the color production.
There are three basic principles of ELISA:
(1) The antigen or antibody can be physically adsorbed on the surface of the solid phase carrier, which may be the hydrophobic part between the surface of the protein and polystyrene adsorbed to each other, and maintain its immunological activity;
(2) The antigen or antibody can be linked to the enzyme through a covalent bond to form an enzyme conjugate, and this enzyme conjugate can still maintain its immunological and enzymatic activities;
(3) After the enzyme conjugate is combined with the corresponding antigen or antibody, it can be determined whether there is an immune reaction according to the color reaction of the added substrate, and the depth of the color reaction is proportional to the amount of the corresponding antigen or antibody in the specimen, Therefore, the test results can be displayed according to the degree of coloration of the substrate.
There are many enzymes used in immunoenzyme technology, such as peroxidase, alkaline phosphatase, β-D-galactosidase, glucose oxidase, carbonic anhydrase, acetylcholinesterase, 6-phosphate glucose deoxygenase, etc. . Commonly used enzymes for ELISA include horseradish peroxidase and alkaline phosphatase, among which horseradish peroxidase is the most common. Because the enzyme destroys the redox reaction, it must be measured immediately after the color is presented. Otherwise, the oxidation in the air will deepen the color and cannot be accurately quantified.
Horseradish peroxidase (HRP) is a glycoprotein and each molecule contains a protonhemin region as a prosthetic group. The concentration and purity of enzymes are often expressed in terms of prosthetic groups. The maximum absorption peak of the prosthetic group of heme chloride in ELISA kit is 403nm, and the maximum absorption peak of HRP enzyme protein is 275nm, so the calculation formula of the enzyme concentration and purity is (A (1cm 403nm 1% of known HRP) = 25, In the formula, 1% means that the percentage concentration of HRP is 100ml containing 1g of enzyme protein, that is, 10mg / ml, so the enzyme concentration is mg / ml calculated as HRP A (1cm 403nm mg / ml = 2.5) HRP purity (RZ) = A403nm / A275nm purity RZ (Reinheit Zahl) value is greater, indicating that the enzyme contains less impurities. The RZ value of high-purity HRP is about 3.0, up to 3.4. The RZ value of HRP used for ELISA detection needs to be above 3.0.
Manual burr grinders are turned by hand, rotating one grinding surface against the other. Coffee mills usually have a handle, providing leverage for the many turns required to grind enough coffee for a cup. The ground coffee is collected in a container which is part of the mill.
Salt, pepper, and spice mills, essentially the same as coffee mills, usually do not have a handle, the entire top rotating instead. While this is less convenient, only a few turns are required to grind enough. The ground product falls directly onto the food being seasoned; the mill has no container. A few designs have abrasive surfaces which do not rotate; each squeeze of the handles moves one flat plate past another, then the plates are restored to their original position by a spring. Many hard spices are available in containers incorporating a simple cone burr grinder, intended to be discarded when empty.
Most grinders can be adjusted to set the fineness of grind.
Manual mills can be used for grinding other food products than they are intended for, but mills designed for pepper grinding are inappropriate for producing finely-ground flour. Laura Ingalls Wilder's novel The Long Winter describes a family grinding wheat in a coffee mill to make flour during months of hardship.
The first Coffee Grinder was made by Richard Dearmann, an English blacksmith from Birmingham, in 1799. Then this grinder was widely distributed in the US, where Increase Wilson patented the first wall coffee grinder in 1818.[citation needed]
Peugeot of France patented a Pepper Grinder in 1842. The mechanism of case-hardened steel cracked the peppercorns before the actual grinding process. The grooves on the Peugeot mechanism were individually cut into the metal and then case-hardened, making them very durable.[citation needed]
Pepper Mill, Salt Mill, Pepper Grinder, Plastic Kitchen Gadget, Kitchen Gadget
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