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Effectiveness of Ciprofloxacin, Levofloxacin, or Moxifloxacin for Treatment of Experimental Staphylococcus aureus Keratitis. Joseph J. Dajcs, 2004.The purpose of this study was to quantitatively compare, in a rabbit keratitis model, the levels of effectiveness of moxifloxacin, levofloxacin, and ciprofloxacin for the treatment of Staphylococcus aureus isolates of diverse antibiotic susceptibilities . Rabbit eyes were intrastromally injected with approximately 100 CFU of methicillin-sensitive or methicillin-resistant S . aureus (MSSA or MRSA, respectively) organisms that were either sensitive or resistant to ofloxacin . One drop of moxifloxacin (0.5%), levofloxacin (0.5%), or ciprofloxacin (0.3%) was topically applied hourly from 4 to 9 (early) or 10 to 15 (late) h postinfection . At 1 h after cessation of therapy, the corneas were harvested, and the number of CFU per cornea was determined . For the ofloxacin-sensitive strains, early treatment of MSSA or MRSA with moxifloxacin, levofloxacin, or ciprofloxacin produced approximately a 5-log decrease in CFU per cornea relative to that in untreated eyes (P  0.0001) . For late therapy of ofloxacin-sensitive strains, moxifloxacin, levofloxacin, and ciprofloxacin produced approximately 5-, 4-, and 2- to 3-log reductions in CFU per cornea, respectively (P
0.0001) . Early treatment of the ofloxacin-resistant strains with either moxifloxacin or levofloxacin produced a
 4-log or
3-log decrease, respectively, in the MSSA or MRSA strains (P
0.0001), whereas ciprofloxacin treatment produced a 1-log decrease in CFU per cornea relative to that in untreated eyes (P = 0.1540) . For late treatment of ofloxacin-resistant strains, levofloxacin and ciprofloxacin failed to significantly reduce the number of CFU per cornea (P
0.3627), whereas moxifloxacin produced a significant reduction in CFU per cornea of approximately 1 log (P
0.0194) . Therefore, for three of the four treatments tested, moxifloxacin demonstrated greater effectiveness than either levofloxacin or ciprofloxacin .
Global Expression Profile of Bacillus subtilis Grown in the Presence of Sulfate or Methionine. Sandrine Auger, 2002.DNA arrays were used to investigate the global transcriptional profile of Bacillus subtilis grown in the presence of sulfate or methionine as the sole sulfur source . The expression of at least 56 genes differed significantly under the two growth conditions . The expression of several genes belonging to the S-box regulon was repressed in the presence of methionine probably in response to S-adenosylmethionine availability . The expression of genes encoding transporters (yhcL, ytmJKLMN, and yxeMO) was high when the sulfur source was methionine or taurine and reduced when it was sulfate . Clostridium pasteurianum F1Fo ATP Synthase: Operon, Composition, and Some Properties. Amaresh Das, 2003.The atp operon encoding F1Fo ATP synthase in the fermentative obligate anaerobic bacterium Clostridium pasteurianum was sequenced . It consisted of nine genes arranged in the order atpI(i), atpB(a), atpE(c), atpF(b), atpH(  ), atpA( ), atpG( ), atpD(ß), and atpC( ), which was identical to that found in many bacteria . Reverse transcription-PCR confirmed the presence of the transcripts of all nine genes . The amount of ATPase activity in the membranes of C . pasteurianum was low compared to what has been found in many other bacteria . The F1Fo complexes solubilized from membranes of C . pasteurianum and Escherichia coli had similar masses, suggesting similar compositions for the F1Fo complexes from the two bacteria . Western blotting experiments with antibodies raised against the purified subunits of F1Fo detected the presence of eight subunits,
, ß,
,
,
, a, b, and c, in the F1Fo complex from C . pasteurianum . The F1Fo complex from C . pasteurianum was activated by thiocyanate, cyanate, or sulfhydryl compounds; inhibited by sulfite, bisulfite, or bicarbonate; and had tolerance to inhibition by dicyclohexylcarbodiimide . The target of thiol activation of the F1Fo complex from C . pasteurianum was F1 . Thiocyanate and sulfite were noncompetitive with respect to substrate Mg ATP but competitive with respect to each other . The F1 and Fo parts of the F1Fo complexes from C . pasteurianum and E . coli bound to each other, but the hybrid F1Fo complexes were not functionally active .
Visualization of an Endophytic Streptomyces Species in Wheat Seed. Justin T. Coombs, 2003.Endophytic filamentous actinobacteria were isolated from surface-sterilized roots of wheat plants . Endophytic colonization of germinating wheat seed was examined using one of these endophytes, Streptomyces sp . strain EN27, tagged with the egfp gene . Endophytic colonization was observed from a very early stage of plant development with colonization of the embryo, endosperm, and emerging radicle .
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