Correlation Of Chemical Data Research Articles

Microbial ecology of chlorinated solvent biodegradation

This study focused on the microbial ecology of tetrachloroethene (PCE) degradation to trichloroethene, cis-1,2-dichloroethene and vinyl chloride to evaluate the relationship between the microbial community and the potential accumulation or degradation of these toxic metabolites. Multiple soil microcosms supplied with different organic substrates were artificially contaminated with PCE. A thymidine analogue, bromodeoxyuridine (BrdU), was added to the microcosms and incorporated into the DNA of actively replicating cells. We compared the total and active bacterial communities during the 50-day incubations by using phylogenic microarrays and 454 pyrosequencing to identify microorganisms and functional genes associated with PCE degradation to ethene. By use of this integrative approach, both the key community members and the ecological functions concomitant with complete PCE degradation could be determined, including the presence and activity of microbial community members responsible for producing hydrogen and acetate, which are critical for Dehalococcoides-mediated PCE degradation. In addition, by correlation of chemical data and phylogenic microarray data, we identified several bacteria that could potentially oxidize hydrogen. These results demonstrate that PCE degradation is dependent on some microbial community members for production of appropriate metabolites, while other members of the community compete for hydrogen in soil at low redox potentials.

Comparison of RAPD, STS, ISSR and AFLP molecular methods used for assessment of genetic diversity in hop (Humulus lupulus L.)

The cluster analysis of ten hop (Humulus lupulus L.) varieties and the comparison of amplified DNA polymorphism were assessed using RAPD, STS, ISSR and AFLP molecular methods. Thirty-five RAPD primers generated an average of 13.4 products with 5.7 polymorphic products (42.3% of polymorphism). Ten STS primer combinations generated an average of 9.3 products with 6.6 polymorphic products (71% of polymorphism). Seven ISSR microsatellite polymorphic primers and seven primer combinations generated an average of 12.9 products with 4.2 polymorphic products (32.6% of polymorphism) in agarose gels and 86.2 products with 24.3 polymorphic products (28.3% of polymorphism) in polyacrylamide gels. A total of 56 AFLP primer combinations generated an average of 91 products with 52.5 polymorphic products (57.6% of polymorphism). All molecular methods accurately distinguished all tested varieties, except for Osvald’s clones (31, 72 and 114), which were only distinguished by AFLP. The similarities between varieties were revealed by cluster analyses. These analyses were very similar for all molecular methods. Pairwise values of JCS (Jaccard’s similarity coefficient) ranged from 0.02 to 1.0 and the mean JCS values ranged from 0.395 (AFLP) to 0.462 (ISSR). The highest correlation coefficient was between ISSR and RAPD (0.966) and the lowest was between AFLP and STS (0.867). STS had the highest correlation of chemical data with molecular methods (0.592) and ISSR had the lowest (0.435).

Survival and multiplication of Legionella pneumophila in municipal drinking water systems.

Studies were conducted to investigate the survival and multiplication of Legionella spp. in public drinking water supplies. An attempt was made, over a period of several years, to isolate legionellae from a municipal system. Sampling sites included the river water supply, treatment plant, finished water reservoir system, mains, and distribution taps. Despite the use of several isolation techniques, Legionella spp. could not be detected in any of the samples other than those collected from the river. It was hypothesized that this was due to the maintenance of a chlorine residual throughout the system. To investigate the potential for Legionella growth, additional water samples, collected from throughout the system, were dechlorinated, pasteurized, and inoculated with Legionella pneumophila. Subsequent growth indicated that many of these samples, especially those collected from areas affected by an accumulation of algal materials, exhibited a much greater ability to support Legionella multiplication than did river water prior to treatment. Chemical analyses were also performed on these samples. Correlation of chemical data and experimental growth results indicated that the chemical environment significantly affects the ability of the water to support multiplication, with turbidity, organic carbon, and certain metals being of particular importance. These studies indicate that the potential exists for Legionella growth within municipal systems and support the hypothesis that public water supplies may contaminate the plumbing systems of hospitals and other large buildings. The results also suggest that useful methods to control this contamination include adequate treatment plant filtration, maintenance of a chlorine residual throughout the treatment and distribution network, and effective covering of open reservoirs.

Plasma and cerebrospinal fluid concentrations of pentazocine in patients: assay by mass fragmentography.

Abstract Mass fragmentography has been used for the determination of low concentrations of pentazocine in blood plasma and cerebrospinal fluid (csf) after intravenous administration of a 30 mg dose to eight patients undergoing neurosurgery under general anaesthesia. A pharmacokinetic analysis based upon mean plasma levels indicated a half-life of 134 min. Lumbar csf levels of pentazocine increased rapidly with mean values from about 3 ng ml−1 at 5 min to 10 ng ml−1 at 30 min and to about 15 ng ml−1 at 90–120 min. The possibility of repeated analyses of drug concentrations in the csf represents an important step towards the correlation of chemical data with clinical effects for centrally acting drugs.

Studies on Soluble Ribonucleic Acid: XI. A Model for the Base Sequence of Serine S-RNA

One of the long range objectives in nucleic acid research is the development of techniques which will permit determination of the base sequence and the correlation of chemical data with biological function for various nucleic acids. Almost from the beginning of the history of S-RNA1 it was recognized that this type of RNA was a particularly suitable object for this type of investigation because of its relatively short chain length and its unique ability to function in protein synthesis as acceptor and donor of activated amino acids. Elucidation of the intimate structure of amino acid specific S-RNAs might be useful in revealing the mechanism of interaction of S-RNA with other nucleic acids such as messenger and ribosomal RNA. Moreover, it might give information on the basis for the specific interaction of S-RNA with the amino acid activating enzymes.