Nucleic acids microbial

Biopolymers are the naturally occurring macromolecular materials that are the components of all living systems. There are three principal categories of biopolymers, each of which is the topic of a separate article in the Eniyclopedia proteins (qv) nucleic acids (qv) and polysaccharides (see Carbohydrates Microbial polysaccharides). Biopolymers are formed through condensation of monomeric units ie, the corresponding monomers are amino acids (qv), nucleotides, and monosaccharides, for proteins, nucleic acids, and polysaccharides, respectively. The term biopolymers is also used to describe synthetic polymers prepared from the same or similar monomer units as are the natural molecules. 

The third pathway for DFN-induction involves detection of microbial nucleic acids by other types of... 

Von Wintzingerode F., Landt O., Ehrlich A., Gobel U. B. Peptide nucleic acid-mediated PGR clamping as a useful supplement in the determination of microbial diversity. Appl. Environ. Microbiol. 2000 66 549-557. 

Phenoxazines — The microbial phenoxazines like actinomycins are well-known antibiotics. Actinomycin D produced by Streptomyces anibioticus is an effective antineoplastic agent that inhibits nucleic acid synthesis. The main function of ommochromes is to act as screening pigments in the eyes of insects and other arthropods, as pattern pigments in the integument, and as excretion products of excess tryptophan. ... 

The previous biomarkers relate to phenotypic assessments of microbial diversity and most will probably measure a restricted part of the total microbial pool, since not alt markers will be expressed uniformly by every cell. In contrast, methods involving the detection of nucleic acids may be directly applicable to all microorganisms provided that the complete extraction of DNA (lysis of cells) or permea-bilization of cells can be achieved. 

For various reasons, the generalizations mentioned above must be regarded as strictly provisional. Analyses utilizing formic acid indicate the presence of more than one phosphorus atom per purine or pyrimidine residue. This discrepancy, it is pointed out, could equally well result from an apparent deficiency of bases, due to error in the analytical technique.160 It is also necessary to consider that some nucleic acids are now known to contain more bases than was previously realized. Thus, 5-(hydroxymethyl)-cytosine is present in various viruses,181-182 and 5-methylcytosine occurs in various animal and plant deoxyribonucleic acids but is absent from those of microbial origin.17-160-1M- 184- 186 Certain microbial deoxyribonucleic acids also contain 6-methylaminopurine.186a Various bacteriophage deoxyribonucleic acids have been found to contain a component which is believed to consist of a D-glucoside186b of 5 -(hydroxymethyl)cytidylic acid. 

A prerequisite step to any rDNA work is the initial isolation of DNA or RNA from the source material (which can be microbial, plant, animal or viral). Numerous methodologies have been developed to achieve nucleic acid purification, and some of these methodologies have been adapted for use in a variety of commercially available purification kits. Although details vary, the general... 

The diversity of functions within a microbial population is important for the multiple functions of a soil. The functional diversity of microbial communities has been found to be very sensitive to environmental changes (Zak et al. 1994 Kandeler et al. 1996,1999). However, the methods used mainly indicate the potential in vitro functionality. Functional diversity of microbial populations in soil may be determined by either expression of different enzymes (carbon utilization patterns, extracellular enzyme patterns) or diversity of nucleic acids (mRNA, rRNA) within cells, the latter also reflecting the specific enzymatic processes operating in the cells. Indicators of functional diversity are also indicators of microbial activity and thereby integrate diversity and function. 

A useful approach to monitor microbial populations in the biotreatment of hazardous wastes involves the detection of specific sequences of nucleic acids by hybridization with complementary oligonucleotide probes. Radioactive labels, fluorescent labels, and other kinds of labels are attached to the probes to increase sensitivity and simplicity of the hybridization... 

Vitamins and Minerals. Milk is a rich source of vitamins and other organic substances that stimulate microbial growth. Niacin, biotin, and pantothenic acid are required for growth by lactic streptococci (Reiter and Oram 1962). Thus the presence of an ample quantity of B-complex vitamins makes milk an excellent growth medium for these and other lactic acid bacteria. Milk is also a good source of orotic acid, a metabolic precursor of the pyrimidines required for nucleic acid synthesis. Fermentation can either increase or decrease the vitamin content of milk products (Deeth and Tamime 1981 Reddy et al. 1976). The folic acid and vitamin Bi2 content of cultured milk depends on the species and strain of culture used and the incubation conditions (Rao et al. 1984). When mixed cultures are used, excretion of B-complex vita-... 

This chapter deals with microbial RNases (1) of interest because of their enzymology or their use in nucleic acid research, with special reference to fungal RNases. 

Other microbial RNases of special interest from points of view of enzymology or of nucleic acid chemistry are briefly mentioned below. 

However, the nucleic acid-based assays for the detection of food pathogens show problems regarding the sensitivity of the polymerase enzyme to environmental contaminants, difficulties in quantification, the generation of false-positives through the detection of naked nucleic acids, non-viable microorganisms or contamination of samples in the laboratory, and may limit the use of PCR for the direct detection of microbial contamination. 

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