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Involvement of Cyclic AMP (cAMP) and cAMP Receptor Protein in Anaerobic Respiration of Shewanella oneidensis. Daad A. Saffarini, 2003.Shewanella oneidensis is a metal reducer that can use several terminal electron acceptors for anaerobic respiration, including fumarate, nitrate, dimethyl sulfoxide (DMSO), trimethylamine N-oxide (TMAO), nitrite, and insoluble iron and manganese oxides . Two S . oneidensis mutants, SR-558 and SR-559, with Tn5 insertions in crp, were isolated and analyzed . Both mutants were deficient in Fe(III) and Mn(IV) reduction . They were also deficient in anaerobic growth with, and reduction of, nitrate, fumarate, and DMSO . Although nitrite reductase activity was not affected by the crp mutation, the mutants failed to grow with nitrite as a terminal electron acceptor . This growth deficiency may be due to the observed loss of cytochromes c in the mutants . In contrast, TMAO reduction and growth were not affected by loss of cyclic AMP (cAMP) receptor protein (CRP) . Fumarate and Fe(III) reductase activities were induced in rich medium by the addition of cAMP to aerobically growing wild-type S . oneidensis . These results indicate that CRP and cAMP play a role in the regulation of anaerobic respiration, in addition to their known roles in catabolite repression and carbon source utilization in other bacteria . Antifungal Therapy of Murine Aspergillus terreus Infection. John R. Graybill, 2004.Aspergillus terreus is a species which is being seen increasingly frequently and which is highly resistant to amphotericin B in vitro and clinically . We evaluated amphotericin B, caspofungin, and posaconazole in a murine model of acute invasive aspergillosis . Caspofungin and posaconazole both appeared beneficial and may be reasonable treatment alternatives for infection with A . terreus . The Rhizobium etli cyaC Product: Characterization of a Novel Adenylate Cyclase Class. Juan Téllez-Sosa, 2002.Adenylate cyclases (ACs) catalyze the formation of 3',5'-cyclic AMP (cAMP) from ATP . A novel AC-encoding gene, cyaC, was isolated from Rhizobium etli by phenotypic complementation of an Escherichia coli cya mutant . The functionality of the cyaC gene was corroborated by its ability to restore cAMP accumulation in an E . coli cya mutant . Further, overexpression of a malE::cyaC fusion protein allowed the detection of significant AC activity levels in cell extracts of an E . coli cya mutant . CyaC is unrelated to any known AC or to any other protein exhibiting a currently known function . Thus, CyaC represents the first member of a novel class of ACs (class VI) . Hypothetical genes of unknown function similar to cyaC have been identified in the genomes of the related bacterial species Mesorhizobium loti, Sinorhizobium meliloti, and Agrobacterium tumefaciens . The cyaC gene is cotranscribed with a gene similar to ohr of Xanthomonas campestris and is expressed only in the presence of organic hydroperoxides . The physiological performance of an R . etli cyaC mutant was indistinguishable from that of the wild-type parent strain both under free-living conditions and during symbiosis . Identification and Mutational Analysis of Bacteriophage PRD1 Holin Protein P35. Pia S. Rydman, 2003.Holin proteins are phage-induced integral membrane proteins which regulate the access of lytic enzymes to host cell peptidoglycan at the time of release of progeny viruses by host cell lysis . We describe the identification of the membrane-containing phage PRD1 holin gene (gene XXXV) . The PRD1 holin protein (P35, 12.8 kDa) acts similarly to its functional counterpart from phage lambda (gene S), and the defect in PRD1 gene XXXV can be corrected by the presence of gene S of lambda . Several nonsense, missense, and insertion mutations in PRD1 gene XXXV were analyzed . These studies support the overall conclusion that the charged amino acids at the protein C terminus are involved in the timing of host cell lysis .
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