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A L Reysenbach

Publications and source records attributed to A L Reysenbach.

25 records · Page 2Linked to original sources

Mineralization of 2,4,6-trinitrophenol (picric acid): characterization and phylogenetic identification of microbial strains.

Four bacterial strains that use picric acid as their sole carbon and energy source were isolated. Mineralization of 14C-UL-picric acid showed that up to 65% of the radioactivity was released as 14CO2. HPLC and UV/Vis spectral analyses indicated complete degradation of picric acid by these organisms. HPLC and LC/MS analyses showed transient formation of 2,4-dinitrophenol during picric acid degradation. Degradation of picric acid was concomitant with stoichiometric release of three moles of nitrite per mole of picric acid. The four picric acid degraders were identified as close relatives of Nocardioides simplex (ATCC 6946) based on their small subunit (16S) rRNA gene sequences.

Base Sequence↗

Thermotoga subterranea sp. nov., a new thermophilic bacterium isolated from a continental oil reservoir.

A thermophilic, strictly anaerobic bacterium, designated strain SL1, was isolated from a deep, continental oil reservoir in the East Paris Basin (France). This organism grew between 50 and 75 degrees C, with an optimum at 70 degrees C. It was inhibited by elemental sulfur and was able to reduce cystine and thiosulfate to hydrogen sulfide. The G+C content (40 mol%), the presence of a lipid structure unique to the genus Thermotoga, and the 16S rRNA sequence of strain SL1 indicated that the isolate belongs to the genus Thermotoga. Based on DNA-DNA hybridization, isolate SL1 does not show species-level similarity with the recognized species T. maritima, T. neapolitana, and T. thermarum. Based on this description of strain SL1, we propose the recognition of a new species: Thermotoga subterranea.

Base Composition↗

Phylogenetic analysis of the hyperthermophilic pink filament community in Octopus Spring, Yellowstone National Park.

The phylogenetic diversity of a well-known pink filament community associated with the 84 to 88 degrees C outflow from Octopus Spring, Yellowstone National Park, was examined. Three phylogenetic types ("phylotypes"), designated EM 3, EM 17, and EM 19, were identified by cloning and sequencing the small subunit rRNA genes (16S rDNA) obtained by PCR amplification of mixed-population DNA. All three phylotypes diverge deeply within the phylogenetic domain Bacteria sensu Woese (C. R. Woese, O. Kandler, and M. L. Wheelis, Proc. Natl. Acad. Sci. USA 87:4576-4579, 1990). No members of the Archaea or Eucarya were detected. EM 3 comprises a unique lineage within the Thermotogales group, and EM 17 and EM 19 are affiliated with the Aquificales. A total of 35 clones were examined, of which the majority (26 clones) were of a single sequence type (EM 17) closely related to Aquifex pyrophilus. In situ hybridization with clone-specific probes attributes the majority sequence, EM 17, to the pink filaments.

Bacteria↗

Differential amplification of rRNA genes by polymerase chain reaction.

The polymerase chain reaction (PCR) is used widely to recover rRNA genes from naturally occurring communities for analysis of population constituents. We have found that this method can result in differential amplification of different rRNA genes. In particular, rDNAs of extremely thermophilic archaebacteria often cannot be amplified by the usual PCR methods. The addition of 5% (wt/vol) acetamide to a PCR mixture containing both archaebacterial and yeast DNA templates minimized nonspecific annealing of the primers and prevented preferential amplification of the yeast small-subunit rRNA genes.

Acetamides↗

Effects of hydrostatic pressure on growth of hyperthermophilic archaebacteria from the juan de fuca ridge.

Two new strains (AL1 and AL2) of hyperthermophilic, sulfur-reducing, heterotrophic archaebacteria from high-temperature (350 degrees C) vents on the Juan de Fuca Ridge were highly barotolerant at their optimal growth temperatures (90 and 100 degrees C, respectively). A trend towards barophily at pressures greater than those encountered in situ at the sea floor was demonstrated for the more extremely thermophilic strain (AL2), implying an ability to thrive in (unexplored) habitats well below accessible vent formations.

Journal Article↗

Characterization, Biosynthesis, and Regulation of Granulose in Clostridium acetobutylicum.

Synthesis of granulose was investigated in 15 solvent-producing Clostridium strains. Only one of the strains did not produce granulose. The structure of granulose in Clostridium acetobutylicum P262 consisted of a high-molecular-weight polyglucan containing only (1-->4) linked d-glucopyranose units. Biosynthesis of granulose in C. acetobutylicum P262 was dependent on ADPglucose pyrophosphorylase, and granulose synthase and mutants defective in granulose accumulation lacked either one or both enzyme activities. Granulose-positive revertants exhibited both enzyme activities. ADPglucose pyrophosphorylase and granulose synthase were not subject to allosteric control by metabolites. Granulose accumulation and the biosynthetic enzyme activities were initiated immediately before the pH breakpoint and were detected in cells only at the end of the exponential growth phase. Granulose accumulation did not occur under conditions of nitrogen limitation, excess carbon, or excess energy.

Journal Article↗