Microbial studies

The introduction of techniques for mutagenesis by UV irradiation or by the use of chemicals considerably extended the applications of microbial studies to nutrition (Davis, 1954-1955). Auxotrophic mutants were produced with nutrient dependencies not shown in the untreated parental strains (Beadle and Tatum, 1940). The fortuitous discovery of penicillin by Fleming and its successful use in the treatment of infections (Florey) promoted exhaustive research into its mode of action. Eventually it was established that penicillin prevented the proliferation of gram-positive bacteria by blocking the synthesis of their cell walls... 

Microbial studies have also been conducted on the biodegradation plots in Utah and have been published by Stark et al,... 

The purpose of the second edition is to meet the need for a ready-to-use text on the validation of aseptic pharmaceutical production and to provide general information and guidelines. It is a compilation of various theories, sterilization variables, and engineering and microbial studies that can be used independently or in combination to validate equipment and processes. The concepts and methods presented in this edition are not intended to serve as a final rule. Reciprocal methods for achieving this purpose exist and should also be reviewed and consulted, if applicable. 

In this contribution we present the unique potential of the above-mentioned Raman spectroscopic techniques for viral and microbial studies in biomedical and pharmaceutical applications. 

Table I. Composition of standard mineral base medium employed in microbial studies.

Microbial studies in MDIs showed that CFG propellant blends tended to be bactericidal against the commonly occurring bacterial contaminant Staphylococcus aureus. The same was found to be true for HFA 134a, however... 

Detail microbial study is crucial to correlate hydrogen production to the microbial group involved. For this purpose, a nucleic acid based technique - terminal restriction fragment length polymorphism (T-RFLP) - was used to identify the... 

The Prospective Approach In this approach the routes of metabolism are first elucidated in microbial systems and then used to predict (and the metabolites facilitate the confirmation of) routes of metabolism in mammals. Also it could be used to explore unanswered questions in mammalian metabolism. For example, microbial studies may reveal a previously undetected mammalian metabolite, elucidate the previously unexplored stereochemical disposition of the xenobiotic in mammalian systems, or be used to study mechanistic aspects concerning the formation of the metabolites. 

Microbial studies have demonstrated a link between carcinogenesis and mutagenesis and will be reviewed briefly with reference to the individual metals tested. 

The host-mediated assay is a simple technique that attempts to bridge the gap between in vitro microbial studies and definitive tests in mammals. The numerous advantages of microorganisms as determinants of hereditary change are utilized in an experimental mammal after it has had an opportunity to metabolize the compound under investigation. This assay was developed to determine the ability of laboratory animals to either potentiate or detoxify compounds in regard to their mutagenic activity. In addition to the studies in mammals, it is essential to conduct the in vitro assay as a control for the host-mediated assay. 

However, the planar chromatographic adsorbent material is, not always suitable for microbial studies. If the test bacterium requires special conditions (e.g., extremely long incubation time) the advantages of the method may not be exploited. The main factors influencing the evaluation of direct bioautography will be discussed below. 

John A. UiiBich and H. O. Halvobson, Chemical and Microbial Studies on Sliced Canned Bacon. 291... 

Electrical power can also be applied to the BES to increase the electrical potential between the anode and cathode electrodes and enable cathodic reactions (reviewed in [1]) not attainable in cathode-limited systems such as MECs. Energy is added to the system with an external power source or by poising the anode potential with a potentiostat. This type of BES is often referred to as a MEC because it enables the electrochemical reduction of protons to hydrogen at the cathode (reviewed in [8]). These BESs are especially suitable for microbial studies and have been used extensively for Geohflcter bacteria. For this reason, we describe the theory and practice of MEC operation using Geobacter cultures in detail in the following sections. 

S. Stroes-Gascoyne and J. M. West, Microbial studies in the Canadian nuclear fuel waste management program. EEMSMicrobiol. Rev. 20 513-590 (1997). 

Crawford, R. L. 1981. The chemical structure of lignin and the use of various lignin preparations for microbial studies, p. 7-19. In R. L. Crawford (ed.) Lignin biodegradation and transformation. John Wiley and Sons. New York. 

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