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Like Bacterium (like + bacterium)
Selected AbstractsMicrobial communities in a porphyry copper tailings impoundment and their impact on the geochemical dynamics of the mine wasteENVIRONMENTAL MICROBIOLOGY, Issue 2 2007Nouhou Diaby Summary The distribution and diversity of acidophilic bacteria of a tailings impoundment at the La Andina copper mine, Chile, was examined. The tailings have low sulfide (1.7% pyrite equivalent) and carbonate (1.4% calcite equivalent) contents and are stratified into three distinct zones: a surface (0-70-80 cm) ,oxidation zone' characterized by low-pH (2.5,4), a ,neutralization zone' (70,80 to 300,400 cm) and an unaltered ,primary zone' below 400 cm. A combined cultivation-dependent and biomolecular approach (terminal restriction enzyme fragment length polymorphism and 16S rRNA clone library analysis) was used to characterize the indigenous prokaryotic communities in the mine tailings. Total cell counts showed that the microbial biomass was greatest in the top 125 cm of the tailings. The largest numbers of bacteria (109 g,1 dry weight of tailings) were found at the oxidation front (the junction between the oxidation and neutralization zones), where sulfide minerals and oxygen were both present. The dominant iron-/sulfur-oxidizing bacteria identified at the oxidation front included bacteria of the genus Leptospirillum (detected by molecular methods), and Gram-positive iron-oxidizing acidophiles related to Sulfobacillus (identified both by molecular and cultivation methods). Acidithiobacillus ferrooxidans was also detected, albeit in relatively small numbers. Heterotrophic acidophiles related to Acidobacterium capsulatum were found by molecular methods, while another Acidobacterium -like bacterium and an Acidiphilium sp. were isolated from oxidation zone samples. A conceptual model was developed, based on microbiological and geochemical data derived from the tailings, to account for the biogeochemical evolution of the Piuquenes tailings impoundment. [source] Isolation of a Carnobacterium maltaromaticum- like bacterium from systemically infected lake whitefish (Coregonus clupeaformis)FEMS MICROBIOLOGY LETTERS, Issue 1 2008Thomas P. Loch Abstract Herein we report on the first isolation of a Carnobacterium maltaromaticum -like bacterium from kidneys and swim bladders of lake whitefish (Coregonus clupeaformis) caught from Lakes Michigan and Huron, Michigan. Isolates were Gram-positive, nonmotile, facultatively anaerobic, asporogenous rods that did not produce catalase, cytochrome oxidase, or H2S, and did not grow on acetate agar. Except for carbohydrate fermentation, many phenotypic characteristics of lake whitefish isolates coincided with those of C. maltaromaticum, the causative agent of pseudokidney disease. Partial sequencing of 16S and 23S rRNA genes, as well as the piscicolin 126 precursor gene, yielded 97% and 98% nucleotide matches with C. maltaromaticum, respectively (accession numbers EU546836 and EU546837; EU643471). Phylogenetic analyses showed that lake whitefish isolates of this study are highly related, yet not fully identical to C. maltaromaticum. The presence of the C. maltaromaticum -like bacterium was associated with splenomegaly, renal and splenic congestion, and thickening of the swim bladder wall with accumulation of a mucoid exudate. Examination of stained tissue sections revealed renal and splenic congestion, vacuolation and bile stasis within the liver, and hyperplasia within the epithelial lining of the swim bladder. The concurrent presence of pathological changes and the C. maltaromaticum -like bacteria suggests that this bacterium is pathogenic to lake whitefish. [source] Euplotes daidaleos and its endocytobiontsTHE JOURNAL OF EUKARYOTIC MICROBIOLOGY, Issue 2 2005SERGEI I. FOKIN Among almost 200 endocytobiotic associations between freshwater ciliates and Chlorella -like algae (A) one Euplotes species,E. daidaleos Diller, Kounaris, 1966 is existing. It was not so far under particular investigation. Comparative study of cell morphology and behavior of "green" and derived from it "white" stocks of the ciliate (C), collected in Italy and Russia were carried out, using light and electron microscopy. The green C usually maintain 30,80 units of A and some bacteria (B), belonging to the different types,Polynucleobacter -like bacterium, ,-subgroup of Proteobacteria (size about 2,10 × 0.4,0.5 ,m) and another eubacterium (size 1,2 × 0.6,0.8 ,m). The number of the first B was much higher in the white C, but could vary between different host cells. According to data obtained with fluorescent microscopy it looks like these B can produce long chains, which consisted of quite short individuals with only one nucleoid. Association between Euplotes and Chlorella within the system is rather a close one: loss of the A after long time cultivation of C in darkness usually did not happen. The majority of the ciliates (96,100%) kept A, but this number often dropped down, apparently as a result of digestion by C of some of the A. Positive phototaxis is almost absent in green E. daidaleos in comparison with that of Paramecium bursaria,Chlorella association. The rate of division was not significantly deviated according to A presence. Moreover, cells of the green Euplotes did not like high level of illumination and in any cases needed some additional food. This situation is also quite opposite to the P. bursaria,Chlorella system. In between 2 and 3 months of cultivation, the main part of the white stocks have lost its viability partly because of disturbance in the cirral pattern. In about 90% of cells some frontal, ventral, transversal and caudal cirri disappeared in different combinations. It is the first indication on some connection between A-symbionts and host morphogenesis. Large food vacuoles almost all time presented in such cells show some kind of problems with digestion as well. E. daidaleos could be considered as three-lateral symbiotic system, promising for further investigations. [source] | ||||||||||