Samples microbiological

Figure 3.175 Molecular sulfur Sg, M 256, CAS 10544-50-0. Occurrence from soil samples (microbiological decomposition), impurities from rubber objects, and by-product in the synthesis of thio-compounds.

Marecek and colleagues developed a new electrochemical method for the rapid quantitative analysis of the antibiotic monensin in the fermentation vats used during its production. The standard method for the analysis, which is based on a test for microbiological activity, is both difficult and time-consuming. As part of the study, samples taken at different times from a fermentation production vat were analyzed for the concentration of monensin using both the electrochemical and microbiological procedures. The results, in parts per thousand (ppt), are reported in the following table. 

For most assays, the incorporated pantothenic acid has to be Hberated en2ymatically. Usually, a combination of pantotheinase and alkaline phosphatase is used to hberate the bound pantothenic acid. The official method for pantothenic acid of the Association of Official Analytical Chemists (AOAC) is the microbiological assay that uses U. Plantarium (A.TCC 8014) as the test organism (71). Samples are extracted at 121°C at pH 5.6—5.7, proteins are precipitated at pH 4.5, and the resulting clear extracts are adjusted to pH 6.8 prior to assay. This procedure is only suitable to determine calcium pantothenate or other free forms of pantothenic acid. 

Spectrophotometric deterrnination at 550 nm is relatively insensitive and is useful for the deterrnination of vitamin B 2 in high potency products such as premixes. Thin-layer chromatography and open-column chromatography have been appHed to both the direct assay of cobalamins and to the fractionation and removal of interfering substances from sample extracts prior to microbiological or radioassay. Atomic absorption spectrophotometry of cobalt has been proposed for the deterrnination of vitamin B 2 in dry feeds. Chemical methods based on the estimation of cyanide or the presence of 5,6-dimethylben2irnida2ole in the vitamin B 2 molecule have not been widely used. 

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). 

The tube was received while still wet, less than 48 hours after removal from the system. Water samples were also taken near the failure site. Resulting microbiological analyses are given in Table 6.6. 

In more recent times chemically defined basal media have been elaborated, on which the growth of various lactic acid bacteria is luxuriant and acid production is near-optimal. The proportions of the nutrients in the basal media have been determined which induce maximum sensitivity of the organisms for the test substance and minimize the stimulatory or inhibitory action of other nutrilites introduced with the test sample. Assay conditions have been provided which permit the attainment of satisfactory precision and accuracy in the determination of amino acids. Experimental techniques have been provided which facilitate the microbiological determination of amino acids. On the whole, microbiological procedures now available for the determination of all the amino acids except hydroxy-proline are convenient, reasonably accurate, and applicable to the assay of purified proteins, food, blood, urine, plant products, and other types of biological materials. On the other hand, it is improbable that any microbiological procedure approaches perfection and it is to be expected that old methods will be improved and new ones proposed by the many investigators interested in this problem. 

Stadler H, Skritek P, Sommer R et al (2008) Microbiological monitoring and automated event sampling at karst springs using LEO-satellites. Water Sci Technol 58 899-909... 

It was then decided that there should be a large main room and two smaller rooms, one for instruments and another for future microbiological work. The latter was hard to justify to management, so it was planned as a utility room for testing laundry products and working with dusty samples. It could be converted if the microbiological work came about. Meanwhile, the room was there, complete with utilities. In addition, there was to be an office, a closet area, and the first aid room mentioned above. 

In the commonest form of microbiological assay used today, samples to be assayed are applied in some form of reservoir (porcelain cup, paper dise or well) to a thin layer of agar seeded with indicator organism. The drug diffuses into the medium and after incubation a zone of growth inhibition forms, in this case as a circle around the reservoir. All other factors being constant, the diameter of the zone of inhibition is, within limits, related to the concentration of antibiotic in the reservoir. 

The number of samples of reference material needed is a commercial issue in the first place. An important variable is the number of samples likely to be sold during the lifetime ( shelf life ) of the reference material. As the lifetime is a function of the intrinsic stability of the material, this variable also affects the amount of raw material is needed. For instance, microbiological materials have limited intrinsic stability, and therefore their lifetime is expected to be shorter than for a dry sediment certified for trace elements. So, under the assumption of an equal number of sam-... 

Moens L, Verreft P, Boonen S, Vanhaecke F and Dams R (1995) Solid sampling electrothermal vaporization for sample introduction in inductively coupled plasma atomic emission spectrometry and inductively coupled plasma mass spectrometry. Spectrochim Acta 508 463-475. Mooijman KA, In t Veld PH, Hoekstra JA, Heisterkamp SH, Havelaar AH, Notermans SHW, Roberts D, Griepink B, Maier E (1992) Development of Microbiological Reference Materials. European Commission Report EUR 14375 EN, Community Bureau of Reference, Brussels. 

Laboratory data may consist of many different collections of tests, such as ECG laboratory tests, microbiologic laboratory tests, and other therapeutic-indication-specific clinical lab tests. However, laboratory data traditionally consist of results from urinalysis, hematology, and blood chemistry tests. Traditional laboratory data can come from what are called local laboratories, which are labs at the clinical site, or from central laboratories where the clinical sites send their samples for analysis. Often when the laboratory data come from a central laboratory, there is no physical CRF page for the data and they are loaded into the clinical data management system directly from an electronic file. Local laboratory data may be represented with a CRF page such as this ... 

Activities encompassed by the stability program include sample storage of either development or production batches (or both), data collection and storage/retrieval, physical, chemical, and microbiological testing, document preparation of regulatory... 

Further sampling should be carried out to ensure potency, lack of microbiological contamination, identity, and the like. It should be noted that because of the above, approved components must therefore be stored to prevent contamination, and that the oldest stock should be used first, and that rejected... 

Elkan and Horvath170 performed a microbiological analysis of samples taken from the north and south deep monitoring wells in December 1974, about 6 months after the dilute waste front had reached the south well. Both denitrifying and methanogenic bacteria were observed. The lower numbers and species diversity of organisms observed in the south monitoring well compared with those in the north well indicated suppression of microbial activity by the dilute wastes. 

Results of pyrolysis mass spectrometric analyses can be influenced by both phenotypic drift and instrument drift. Phenotypic drift can result from variations in culture growth immediately prior to analysis, and from variations during serial subculturing before analysis.125,126 However, this type of drift is not perceived as an obstacle in microbiological work because it can be largely overcome by standardizing culture conditions and by analyzing more than one sample from each culture. 

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