Microbiological, physiological methods

The use of mutant 34486 of Neurospora crassa for the microbiological assay of ch oline has been described (8). A physiological method has also been used in which the ch oline is extracted after hydrolysis from a sample of biological material and acetylated. The acetylcholine is then assayed by a kymographic procedure, in which its effect in causing contraction of a piece of isolated rabbit intestine is measured (33). 

Vitamin Br, Absorption, Distribution, and Excretion, Physiology and Pathology of (Grasbeck), 3, 299 Vitamins, Microbiological Assay Methods for (Baker and Sobotka), 5, 173... 

This method of learning how to approach a similar project correctly, causes a bias In the appraisal of the relative efforts required for the research. Of some 20 research years In the project (about half by doctoral students) 20 % of the time was for analytical chemistry, 70 % for microbiology, physiology and biochemistry, and 10 % for engineering. For this presentation of the waste treatment It Is only necessary to know that the s -trlazlnes are degraded quantitatively to and CO2 (and, where appropriate,... 

Biological, chemical and physiological methods are available for the measurement of pantothenic acid (vitamin B5). However, the development of analytical methods for pantothenic acid lags far behind that for other vitamins. A classical microbiological assay remains the most practical method to measure pantothenic acid, mainly because there has been little interest in assessing pantothenic acid deficiency. 

In biological materials, various nonspecific precipitants have been used in the gravimetric deterrnination of choline, including potassium triiodide, platinum chloride, gold chloride, and phosphotungstic acid (28). Choline may also be determined spectrophotometricaHy and by microbiological, enzymatic, and physiological assay methods. 

It may be important to consider the variability of the matrix due to the physiological nature of the sample. In the case of LC-M/MS-based procedures, appropriate steps should be taken to ensure the lack of matrix effects throughout application of the method, especially if the nature of the matrix changes from the matrix used during method validation. For Microbiological and immunoassay, if separation is used prior to assay for study samples but not for standards, it is important to establish recovery and use it in determining results. In this case, possible approaches to assess efficiency and reproducibility of recovery are ... 

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