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Engaging undergraduate students in scientific research promises substantial benefits, but it is not accessible to all students and is rarely implemented early in college education, when it will have the greatest impact. An inclusive Research Education Community (iREC) provides a centralized scientific and administrative infrastructure enabling engagement of large numbers of students at different types of institutions. The Science Education Alliance-Phage Hunters Advancing Genomics and Evolutionary Science (SEA-PHAGES) is an iREC that promotes engagement and continued involvement in science among beginning undergraduate students. The SEA-PHAGES students show strong gains correlated with persistence relative to those in traditional laboratory courses regardless of academic, ethnic, gender, and socioeconomic profiles. This persistent involvement in science is reflected in key measures, including project ownership, scientific community values, science identity, and scientific networking.

The gene encoding the reverse gyrase (rgy) of Pyrococcus furiosus was analyzed to characterize its genetic structure and determine the biochemical activity of its protein. Nucleotide sequence analysis of the Pyrococcus furiosus rgy gene indicated the presence of 1,214 amino acids that were homologous by 48% to the reverse gyrase of Methanococcus jannaschii. The rgy gene also encoded a monomeric protein that was composed of a helicase-like module and a type I topoisomerase module.

The genome of the anaerobic thermophilic eubacterium Caldocellum saccharolyticum was analyzed by pulsed field gel electrophoresis. The restriction endonucleases NheI and SstII cleaved the genome into 23 and 21 fragments, respectively, and the sums of the fragments gave a genome size of approximately 2.78 Mbp. Hybridization of probes for several cellulolytic and hemicellulolytic genes, as well as a 16S ribosomal RNA gene, gave complex signals on PFGE-separated restriction fragments. Mapping of the genome by use of linking clone hybridizations had been initiated. [ABSTRACT FROM AUTHOR]

The formation of chromium-DNA adducts, and chromium-mediated peptide-DNA or amino acid-DNA cross-links was measured after treatment of calf thymus DNA and defined DNA polynucleotides in vitro with potassium dichromate in the presence of glutathione or cysteine. The level of chromium bound to DNA after reaction with chromium (VT) in the presence of glutathione increased with increasing glutathione concentration to a level of ˜1.4 x 10 chromium per nucleotide. Glutathione and chromium were associated with the DNA in a 1:1 ratio. Reaction of chromhim(VI) with DNA in the presence of cysteine led to a maximal level of chromium binding that was 10-fold lower than that measured with glutathione, with 2–4 cysteine bound per chromium. The thiol-chromium-DNA complexes were stable to dialysis at room temperature against diethytenetriaminepentaacetic add, orthophenanthroline and ethylenediaminetetraacetie acid. However, when the chromium -DNA complexes were dialyzed against ethylenediaminetetraacetie acid at 37°C to chelate bound chromium, equivalent amounts of chromium and thiol were lost from the DNA, suggesting that thiol was associated with the DNA-bound chromium. These results suggest that chromium mediates cross-linking of cysteine and glutathione to DNA, to form glutathione-chromium-DNA and (cysteine)-chromium-DNA complexes. In order to probe the DNA base and sequence specificity of glutathione-chromium-DNA adduct formation, chromium and glutathione binding to polynucleotides of defined composition was determined. Preferential binding of chromium to guanine-containing polynucleotides was observed. These results suggest that the interaction of chromium with thiol-containing amino acids and peptides may be important in chromium genotoxicity, and indicate that the thiol-activated chromium may target guanine bases in DNA. [ABSTRACT FROM PUBLISHER]