The phylogenetic diversity of Bacteria and Archaea within a biodegraded, mesothermic petroleum reservoir in the Schrader Bluff Formation of Alaska was examined by two culture-independent methods based on fosmid and small-subunit rRNA gene PCR clone libraries. Despite the exclusion of certain groups by each method, there was overall no significant qualitative difference in the diversity of phylotypes recovered by the two methods. The resident Bacteria belonged to at least 14 phylum-level lineages, including the polyphyletic Firmicutes, which accounted for 36.2% of all small-subunit rRNA gene-containing (SSU(+)) fosmid clones identified. Members of uncultured divisions were also numerous and made up 35.2% of the SSU(+) fosmid clones. Clones from domain Archaea accounted for about half of all SSU(+) fosmids, suggesting that their cell numbers were comparable to those of the Bacteria in this microbial community. In contrast to the Bacteria, however, nearly all archaeal clones recovered by both methods were related to methanogens, especially acetoclastic methanogens, while the plurality of bacterial fosmid clones was affiliated with Synergistes-like acetogenic Firmicutes that possibly degrade longer-chain carboxylic acid components in the crude oil to acetate. These data suggest that acetate may be a key intermediary metabolite in this subsurface anaerobic food chain, which leads to methane production as the primary terminal electron sink.

A 150-kDa cytadhesin-like protein from Mycoplasma gallisepticum has been identified. A previously described 583-bp fragment (

A second cytadhesin-like protein, MGC2, was identified in the avian respiratory pathogen Mycoplasma gallisepticum. The 912-nucleotide mgc2 gene encodes a 32.6-kDa protein with 40.9 and 31.4% identity with the M. pneumoniae P30 andM. genitalium P32 cytadhesins, respectively. Functional studies with reverse transcription-PCR, immunoblotting, double-sided immunogold labeling, and attachment inhibition assays demonstrated homology to the human mycoplasmal P30 and P32 cytadhesins. These findings suggest that there is a family of cytadhesin genes conserved among pathogenic mycoplasmas infecting widely divergent hosts.

No abstract

Poultry consuming diets contaminated with citrinin excrete copious quantities of urine and exhibit increased water consumption. The present study was conducted to determine if citrinin acts directly on the kidneys and, if so, to provide a detailed physiological evaluation of the nephrotoxic effects of citrinin. Single Comb White Leghorn pullets were anesthetized and prepared for renal function studies. Ureteral urine was collected during a pre-infusion period (30 min), during unilateral renal portal infusion of 200 ppm citrinin (30 min), and during a recovery period following citrinin infusion (90 min). Pilot studies had shown that 200 ppm citrinin is the lowest dose capable of causing consistent unilateral responses when infused at a rate of .2 ml/kg body weight (BW) X min. The responses of the portal-infused kidneys were compared with the responses of the contralateral (uninfused) kidneys to determine the direct effects of citrinin. Citrinin had no acute direct (unilateral) effect on glomerular filtration rate, renal plasma flow rate, urine pH, or fractional calcium or magnesium excretion. Citrinin caused rapid unilateral increases in urine flow rates, free water clearance, and in fractional sodium, potassium, and inorganic phosphate excretion. Increased solute excretion did not compensate for increased free water clearance, as reflected by a significant decrease in urine osmolality. Recovery from the effects of citrinin occurred within 30 min after cessation of unilateral renal portal infusion. No histopathological damage was seen when citrinin was infused at 200 and 800 ppm, although dose-related increases in urine flow and decreases in urine osmolality were observed.(ABSTRACT TRUNCATED AT 250 WORDS)