Analysis bacterial content

An anaerobic bacterial enrichment cnltnre was used to examine the dechlorination of 2,3,4,5-tetrachlorobiphenyl that prodnced 2,3,5-trichlorobiphenyl exclusively. Although there was no alteration in the valnes of 5 C, compound-specific analysis of Arochlor 1268 showed that there was a trend for decreasing C abundance with increasing content of chlorine. This is consistent with dechlorination of the congeners with more chlorine substituents. 

Lipids, relatively nonpolar chemical substances found in plant, bacterial, and animal cells, are among the most ubiquitous of biomolecules. In this experiment, a lipid extract of ground nutmeg will be purified by chromatography on a silica gel column. Analysis of the lipid extract by thin-layer chromatography will provide the classification of the components in the extract. The unknown lipids will be further characterized by saponification and analysis of the fatty acid content by gas chromatography. For an abbreviated experiment, students may be provided samples of natural oils and fats that can be analyzed by saponification and gas chromatography. 

Table n shows the changes in the composition of the bacterial substance which occur when 100 mg. of log cells at the depletion point grow into valine cells (if that is the limiting amino acid), or into threonine cells if threonine is limited. The amounts formed from 100 mg. at the point of depletion average 145 mg. in the case of valine and 190 mg. in the case of threonine. The determination of wall substance by mechanical disruption and the determination of membrane substance by lipide analysis have been outlined. The other data are obtained by way of conventional procedures DNA (deoxyribonucleic acid) by diphenylamine, and completely independently by thymine RNA (ribonucleic acid) by ultraviolet extinction and cytoplasmic protein from nitrogen determinations corrected for the nitrogen content of the other components. 

The DNA content of the smallest genome such as that of the DNA virus SV40 is of the order of thousands of base pairs and the analysis of even such small genomes would be impossible if they could not be reproducibly fragmented into smaller pieces. The discovery of restriction endonucleases from several bacterial species provided the tool for the specific cleavage of DNA. Once cleaved, the fragments of different sizes could be separated electrophoretically, isolated, and analyzed. 

Table 1.5 Average contents of carbonyl compounds identified in Cbardonnay and Cabernet Sauvignon wines before and after MLF operated by two different Oenococcus oeni bacterial strains, n.f. = not found. Amounts expressed as internal standard o-chlorobenzaldehyde (I.S.). Quantified on basis of 1 of 2 synlanti oxime peaks. Amounts calculated as 1-heptanol (I.S.) in the GC/MS analysis performed without synthesis of the PFBOA-derivafives.

Fig. 21.1. Plots of melting point (TM) vs. 3HV mole fraction (Fv) of bacterially synthesized random P(3HB-co-3HV)s. The circles indicate T values for P(3HB-co-3HV) samples which show a single DSC melting peak. The T values indicated by triangles are those for P(3HB-co-3HV) samples which were bacterially synthesized as mixtures composed of two main copolymer components with different 3HV mole fractions, and so show well-resolved two DSC melting peaks. For these mixed samples, the 3HV contents of two components were determined by analyzing the solution H NMR spectra based on the statistical model (for details of spectral analysis, see Ref. [28]). Hence, for these samples, the Tm values are plotted against the 3HV fractions of the component copolymers. (Reproduced from Ref. [28] with permission.)...

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