Showing papers by "Alfons J. M. Stams published in 1997"

Caloramator proteoclasticus sp. nov., a New Moderately Thermophilic Anaerobic Proteolytic Bacterium

Abstract: A new moderately thermophilic proteolytic anaerobe, strain UT, was isolated from mesophilic granular methanogenic sludge. The cells were spore-forming, motile rods that were 0.4 μ.m wide and 2.4 to 4 μ.m long and stained gram negative. Electron micrographs of thin sections revealed the presence of an atypical gram-positive cell wall. Optimum growth occurred at 55°C and at pH values between 7.0 and 7.5, with a doubling time of 30 min. The DNA base ratio of guanine plus cytosine was 31 mol%. The bacterium fermented proteins mainly to acetate, hydrogen, formate, and branched-chain fatty acids. Several amino acids, including glutamate, aspartate, arginine, histidine, threonine, methionine, and branched-chain amino acids, were also utilized. Glutamate was degraded to acetate, formate, hydrogen, and alanine. In addition, the strain degraded carbohydrates, including glucose, fructose, mannose, cellobiose, and starch, to acetate, ethanol, formate, lactate, and hydrogen. The results of a 16S rRNA sequence analysis phylogenetically placed strain UTin the low-guanine-plus-cytosine-content subgroup of the gram-positive phylum. We propose to classify the described strain in the genus Caloramator as a new species, Caloramator proteoclasticus. The type strain of C. proteoclasticus, strain U, has been deposited in the Deutsche Sammlung von Mikroorganismen as strain DSM 10124.

Detection and quantification of Desulforhabdus amnigenus in anaerobic granular sludge by dot blot hybridization and PCR amplification

Abstract: A species-specific 16S rRNA oligonucleotide probe (ASRB1) was developed for the detection of Desulforhabdus amnigenus in anaerobic granular sludge. The presence of nucleic acids from cells of D. amnigenus in granular sludge was determined using ASRBI as a specific primer for polymerase chain reaction (PCR) amplification or as a probe for dot blot hybridizations. The detection threshold and the reproducibility of these two methods were determined with sludge amended with 10 4 -10 10 D. amnigenus cells per gram of volatile suspended solids (VSS), For D. amnigenus cells with a ribosomal RNA content of 15 fg cell -1 , the lowest number of target cells detected by hybridization was 1 x 10 8 cells g -1 VSS. With the PCR amplification method the lowest number of target cells which could be detected was 1 x 10 7 g -1 VSS. This corresponds to a threshold level for hybridization of 0.1-0.001‰ of the total bacterial sludge population, while the threshold level obtained with the PCR approach amounted to 0.01-0.0001‰. The rRNA content of D. amnigenus was found to be affected by the growth rate and the growth phase, and it ranged from 19 fg cell -1 in slow-growing cultures to 90 fg cell -1 in fast-growing cultures. Therefore, the detection threshold of the dot blot hybridization method for fast-growing cells is lower than for slow-growing cells.

Taxonomic description of Methanococcoides euhalobius and its transfer to the Methanohalophilus genus

Abstract: A sequence analysis of the 16S-rRNA of Methanococcoides euhalobius revealed that this organism was highly related to members of the genus Methanohalophilus On the basis of sequence data, an oligonucleotide probe specific to Methanohalophilus species was designed Hybridization studies with this probe confirmed close relationship of Methanococcoides euhalobius to Methanohalophilus species Therefore, we propose that Methanococcoides euhalobius should be transferred to the genus Methanohalophilus as Methanohalophilus euhalobius