GB/T 21786-2025 English PDF

Standard ID	USD	BUY PDF	Lead-Days	Standard Title (Description)	Status
GB/T 21786-2025	RFQ	ASK	3 days	Chemicals - Test method of bacterial reverse mutation	Valid
GB/T 21786-2008	209	Add to Cart	3 days	Chemicals -- Test method of bacterial reverse mutation	Valid

Basic data

Standard ID: GB/T 21786-2025 (GB/T21786-2025)
Description (Translated English): Chemicals - Test method of bacterial reverse mutation
Sector / Industry: National Standard (Recommended)
Date of Implementation: 2025-12-01
Older Standard (superseded by this standard): GB/T 21786-2008

GB/T 21786-2008: Chemicals -- Test method of bacterial reverse mutation

---This is a DRAFT version for illustration, not a final translation. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.) will be manually/carefully translated upon your order.
Chemicals. Test method of bacterial reverse mutation ICS 13.300; 11.100 A80 National Standards of People's Republic of China Chemicals bacterial reverse mutation assay method Posted 2008-05-12 2008-09-01 implementation Administration of Quality Supervision, Inspection and Quarantine of People's Republic of China Standardization Administration of China released

Foreword

This standard is identical with the Organisation for Economic Co-operation and Development (OECD) Chemicals testing guidelines No. 471 (1997) "Bacterial reverse mutation test Test "(in English). The editorial changes made the following standards. --- Increasing the scope section; --- Change the unit of measure of legal units of measurement; --- Deleted the reference section of the OECD. This standard is managed by the National Standardization Technical Committee chemicals dangerous (SAC/TC251) and focal points. This standard is drafted by. China Center for Disease Control and Prevention of Occupational Health and Poison Control. Participated in the drafting of this standard. Beijing Center for Disease Control and Prevention, Ningbo CIQ. The main drafters of this standard. Deng Ying, Xiao Mu group, Ai Wei Wu, Zhaochao Ying, Long-ho again. OECD Introduction Principle experiment is to detect the presence of the test strains and restore revertant ability to synthesize essential amino acids. Reverse mutation occurred in the absence of bacteria Lack of essential amino acids under specific growth conditions, while the parent strain can not grow, it can be detected. When auxotrophic strains as the test sample Reverse mutation occurs with the latter, which restored the ability to synthesize a particular amino acid, so the bacteria can be formed in a medium that does not contain amino acids Fall, and those strains have not mutated and mutant strains due to the parent strain can not synthesize certain amino acids can not contain the amino Formed colonies on acid medium. 2. Point mutation is the cause of many human genetic diseases, but also, there are ample evidence that humans and experimental animal cells Oncogenes and tumor suppressor gene point mutations and tumorigenesis. Bacterial reverse mutation test is rapid, economical and relatively simple operation, etc. advantage. Many test strain also has certain features, make it more sensitive to certain types of mutagens, these features include reverse mutation sites should A DNA sequence, cell permeability of macromolecules and DNA repair system to eliminate (deletion) or error-prone DNA repair Increase in the number. Test results obtained by specific strains may provide valuable information for the study of genetic mutations induced by toxic substances. Has established a large number of different bacteria contain structures chemicals reverse mutation test results database from which you can get the required information, at the same time, Also testing different physical and chemical properties of chemicals (for example, volatile matter) to establish a sound approach. 3. Bacterial mutation assay recovery application is a prokaryotic cell, which in terms of absorption, metabolism, chromosome structure, DNA repair and other processes and feeding Milk animal cells, there may be differences. And this test is an in vitro test, generally need to add exogenous metabolic activation system. But exogenous metabolic activation The system can not fully simulate the in vivo metabolic conditions, therefore, the results of this test can not test a sample of mammalian mutagenicity and carcinogenicity Provide direct evidence. 4. Bacterial reverse mutation test is usually used as genetic toxicity screening test, especially suitable for test sample-induced point mutation detection capability Measurement. A large number of research data shows that a lot of positive results obtained in this trial chemicals in other trials also have mutagenic activity. but There are also some mutagenic agents in this test (results) negative examples, this test may be due to the presence of such defects in the specific endpoint detection Nature, different metabolic activation and the differences in bioavailability and other causes. On the other hand, some of the increased sensitivity of the present test Factors can also result in overestimation of mutagenic activity. 5. Bacterial recovery test is not suitable for the evaluation of certain types of chemicals, for example, it has a strong bactericidal effect of compound (such as some antibiotics Su), or known that mammalian cells specific for replication of interfering compounds (e.g., topoisomerase inhibitors, nucleotides Like, etc.), these substances chosen mammalian mutagenicity test is more appropriate. 6. Although many positive results obtained in this trial chemicals are mammalian carcinogens, but this correlation is not absolute But with the kind of relevant chemicals. There are some carcinogens can not be detected by this test, because these substances by other, non-heritage Biography carcinogenic mechanisms or do not have the test strains (presence) of cancer-causing mechanisms. Chemicals bacterial reverse mutation assay method

1 Scope

This standard specifies the chemical bacterial reverse mutation test scope, terms and definitions, basic test principle, test methods, and test data report. This standard is applicable to the detection of chemicals (except for bactericidal effect) mutagenicity.

2 Terms and definitions

The following terms and definitions apply to this standard. 2.1 Strain (histidine and tryptophan, respectively) mutations, to produce an amino acid does not depend on external strain provided. 2.2 It can cause changes in DNA base material. In the back to change the test, this change can occur in the primary mutation site in the bacterial genome The mutation may also occur in the second site. 2.3 DNA can cause single or multiple base pairs additions or deletions, and then change the RNA reading frame material.

3 test basic principles

3.1 bacterial suspension were under or without the addition of exogenous metabolic activation system conditions with a test sample contact at the plate incorporation assay , The above mixture was thoroughly mixed with top agar and quickly poured into the bottom agar plates (minimum nutrient agar). In the pre-incubation experiment, First with a test sample mixed bacterial suspension were preincubated and then thoroughly mixed with top agar, poured into rapidly bottom agar plate (Minimum Nutrient agar). Said plates were incubated 2d ~ 3d after counting the number of colonies and reply with the solvent control group, spontaneous responses were colonies Comparison. 3.2 Bacterial reverse mutation test are several methods of operation, which is the most commonly used plate incorporation assay, preincubation method, shake culture and suspension culture Raising method. There is an improved method for the detection of gases or vapors. Mainly plate incorporation and preincubation method described in Standard 3.3. Both of these methods in bars or without added metabolic activation system It can be carried out under the member. Some chemicals more efficiently by pre-incubation method include short chain aliphatic nitrosamines, divalent metals, aldehydes, azo dyes and diazo Compound, Senecio alkaloids, allyl compounds and nitro compounds. In the study also found that certain classes of chemicals with a standard square Methods such as plate incorporation and preincubation methods can not always be detected positive result, this case should be regarded as "exceptional" and strongly recommended for other On behalf of the test program for testing. In the literature, alternative methods have been used for the following "special cases" mutagenicity were identified (while providing used Examples of test procedures), "special case" generally include azo and diazo compounds, gaseous or volatile substances and glucoside and the like. The standard Changes in the method should be scientific evidence. Test Method 4 4.1 Test preparation 4.1.1 Bacteria 4.1.1.1 fresh bacterial cultures should be grown to exponential growth late or early stationary phase (bacteria concentration of about 109/mL), growth has been ......

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