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In Vitro Activities of Iodonium Salts against Oral and Dental Anaerobes. Ellie J. C. Goldstein, 2004.The comparative in vitro activities of 11 iodonium salt compounds, 0.12% chlorhexidine, and four antimicrobial agents against 322 anaerobic and fastidious potential dental and periodontal bacterial pathogens were studied . Iodonium salts 3, 4, 5, 9, and 10 had in vitro activities comparable to that of chlorhexidine against most isolates . These compounds may be suitable for incorporation into an oral mouthwash . Identification of Differential Gene Expression in Bacteria Associated with Coral Black Band Disease by Using RNA-Arbitrarily Primed PCR. Jorge Frias-Lopez, 2004.RNA-arbitrarily primed PCR techniques have been applied for the first time to identify differential gene expression in black band disease (BBD), a virulent coral infection that affects reef ecosystems worldwide . The gene activity for the BBD mat on infected surfaces of the brain coral Diploria strigosa was compared with that for portions of the BBD mat that were removed from the coral and suspended nearby in the seawater column . The results obtained indicate that three genes (DD 95-2, DD 95-4, and DD 99-9) were up-regulated in the BBD bacterial mat on the coral surface compared to the transcript base levels observed in the BBD mat suspended in seawater . Clone DD 95-4 has homology with known amino acid ABC transporter systems in bacteria, while clone DD 99-9 exhibits homology with chlorophyll A apoprotein A1 in cyanobacteria . This protein is essential in the final conformation of photosystem I P700 . DD 95-2, the only gene that was fully repressed in the BBD mat samples suspended in seawater, exhibited homology with the AraC-type DNA binding domain-containing proteins . These transcriptional activators coordinate the expression of genes essential for virulence in many species of gram-negative bacteria . Inactivation of the selB Gene in Methanococcus maripaludis: Effect on Synthesis of Selenoproteins and Their Sulfur-Containing Homologs. Michael Rother, 2003.The genome of Methanococcus maripaludis harbors genes for at least six selenocysteine-containing proteins and also for homologs that contain a cysteine codon in the position of the UGA selenocysteine codon . To investigate the synthesis and function of both the Se and the S forms, a mutant with an inactivated selB gene was constructed and analyzed . The mutant was unable to synthesize any of the selenoproteins, thus proving that the gene product is the archaeal translation factor (aSelB) specialized for selenocysteine insertion . The wild-type form of M . maripaludis repressed the synthesis of the S forms of selenoproteins, i.e., the selenium-independent alternative system, in selenium-enriched medium, but the mutant did not . We concluded that free selenium is not involved in regulation but rather a successional compound such as selenocysteyl-tRNA or some selenoprotein . Apart from the S forms, several enzymes from the general methanogenic route were affected by selenium supplementation of the wild type or by the selB mutation . Although the growth of M . maripaludis on H2/CO2 is only marginally affected by the selB lesion, the gene is indispensable for growth on formate because M . maripaludis possesses only a selenocysteine-containing formate dehydrogenase . The IS1111 Family Members IS4321 and IS5075 Have Subterminal Inverted Repeats and Target the Terminal Inverted Repeats of Tn21 Family Transposons. Sally R. Partridge, 2003.IS5075 and IS4321 are closely related (93.1% identical) members of the IS1111 family that target a specific position in the 38-bp terminal inverted repeats of Tn21 family transposons and that are inserted in only one orientation . They are 1,327 bp long and have identical ends consisting of short inverted repeats of 12 bp with an additional 7 bp (TAATGAG) or 6 bp (AATGAG) to the left of the left inverted repeats and 3 bp (AGA) or 4 bp (AGAT) to the right of the right inverted repeat . Circular forms of IS5075 and IS4321 in which the inverted repeats are separated by abutting terminal sequences (AGATAATGAG) were detected . A similar circular product was found for the related ISPa11 . Transposition of IS4321 into the 38-bp target site was detected, but a flanking duplication was not generated . The precisely reconstituted target site was also identified . Over 50 members of the IS1111 family were identified . They encode related transposases, have related inverted repeats, and include related bases that lie outside these inverted repeats . In some, the flanking bases number 5 or 6 on the left and 4 or 3 on the right . Specific target sites were found for several of these insertion sequence (IS) elements . IS1111 family members therefore differ from the majority of IS elements, which are characterized by terminal inverted repeats and a target site duplication, and from members of the related IS110 family, which do not have obvious inverted repeats near their termini . The Surface-Associated and Secreted MopE Protein of Methylococcus capsulatus (Bath) Responds to Changes in the Concentration of Copper in the Growth Medium. Odd A. Karlsen, 2003.Expression of surface-associated and secreted protein MopE of the methanotrophic bacterium Methylococcus capsulatus (Bath) in response to the concentration of copper ions in the growth medium was investigated . The level of protein associated with the cells and secreted to the medium changed when the copper concentration in the medium varied and was highest in cells exposed to copper stress .
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