Description of Gluconacetobacter sacchari sp. nov., a new species of acetic acid bacterium isolated from the leaf sheath of sugar cane and from the pink sugar-cane mealy bug

A new species of the genus Gluconacetobacter, for which the name Gluconacetobacter sacchari sp. nov. is proposed, was isolated from the leaf sheath of sugar cane and from the pink sugar-cane mealy bug, Saccharicoccus sacchari, found on sugar cane growing in Queensland and northern New South Wales, Australia, The nearest phylogenetic relatives in the alpha-subclass of the Proteobacteria are Gluconacetobacter liquefaciens and Gluconacetobacter diazotrophicus, which have 98.8-99.3% and 97.9-98.5% 16S rDNA sequence similarity, respectively, to members of Gluconacetobacter sacchari. On the basis of the phylogenetic positioning of the strains, DNA reassociation studies, phenotypic tests and the presence of the Q10 ubiquinone, this new species was assigned to the genus Gluconacetobacter. No single phenotypic characteristic is unique to the species, but the species can be differentiated phenotypically from closely related members of the acetic acid bacteria by growth in the presence of 0.01% malachite green, growth on 30% glucose, an inability to fix nitrogen and an inability to grow with the L-amino acids asparagine, glycine, glutamine, threonine and tryptophan when D-mannitol was supplied as the sole carbon and energy source. The type strain of this species is strain SRI 1794(T) (= DSM 12717(T)).

Lessons from an estivating frog: sparing muscle protein despite starvation and disuse

Long (6- to 9-mo) bouts of estivation in green-striped burrowing frogs lead to 28% atrophy of cruralis oxidative fibers (P < 0.05) and some impairment of in vitro gastrocnemius endurance (P < 0.05) but no significant deficit in maximal twitch force production. These data suggest the preferential atrophy of oxidative fibers at a rate slower than, but comparable to, laboratory disuse models. We tested the hypothesis that the frog limits atrophy by modulating oxidative stress. We assayed various proteins at the transcript level and verified these results for antioxidant enzymes at the biochemical level. Transcript data for NADH ubiquinone oxidoreductase subunit 1 (71% downregulated, P < 0.05) and ATP synthase (67% downregulated, P < 0.05) are consistent with mitochondrial quiescence and reduced oxidant production. Meanwhile, uncoupling protein type 2 transcription (P < 0.31), which is thought to reduce mitochondrial leakage of reactive oxygen species, was maintained. Total antioxidant defense of water-soluble (22.3 +/- 1.7 and 23.8 +/- 1.5 mu M/mu g total protein in control and estivator, respectively, P = 0.53) and membrane-bound proteins (31.5 +/- 1.9 and 42.1 +/- 7.3 mu M/mu g total protein in control and estivator, respectively, P = 0.18) was maintained, equivalent to a bolstering of defense relative to oxygen insult. This probably decelerates muscle atrophy by preventing accumulation of oxidative damage in static protein reserves. Transcripts of the mitochondrially encoded antioxidant superoxide dismutase type 2 ( 67% downregulated, P < 0.05) paralleled mitochondrial activity, whereas nuclear-encoded catalase and glutathione peroxidase were maintained at control values (P = 0.42 and P = 0.231), suggesting a dissonance between mitochondrial and nuclear antioxidant expression. Pyruvate dehydrogenase kinase 4 transcription was fourfold lower in estivators (P = 0.11), implying that, in contrast to mammalian hibernators, this enzyme does not drive the combustion of lipids that helps spare hypometabolic muscle.

Meganema perideroedes gen. nov., sp nov., a filamentous alphaproteobacterium from activated sludge

An industrial wastewater treatment plant at Grindsted, Denmark, has suffered from bulking problems for several years caused by filamentous bacteria. Five strains were isolated from the sludge by micromanipulation, Phylogenetic analysis of the 16S rRNA gene sequences showed that the strains formed a monophyletic cluster in the Alphaproteobacteria, and they were phenotypically different from their closest relatives and from all hitherto known filamentous bacteria described (closest relative Brevundimonas vesicularis ATCC 11426(T), 89(.)8% sequence similarity). In pure culture, the cells (1(.)5-2(.)0 mu m) in filaments are Gram-negative and contain polyphosphate and polyhydroxyalkanoates. The optimum temperature for growth is 30 degrees C and the strains grow in 2 % NaCl and are oxidase- and catalase-positive. Ubiquinone 10 is the major quinone. The major fatty acid (C-18: 1 omega 7c) and smaller amounts of unsaturated fatty acids, 3-hydroxy fatty acids with a chain length of 16 and 18 carbon atoms and small amounts of 10-methyl-branched fatty acids with 18 carbon atoms (C-19: 0 10-methyl) affiliated the strains with the Methylobacterium/Xanthobacter group in the Alphaproteobacteria. The G + C content of the DNA is 42(.)9 mol% (for strain Gr1(T)). The two most dissimilar isolates by 16S rRNA gene comparison (Gr1(T) and Gr10; 97(.)7 % identical) showed 71(.)5 % DNA-DNA relatedness. Oligonucleotide probes specific for the pure cultures were designed for fluorescence in situ hybridization and demonstrated that two filamentous morphotypes were present in the Grindsted wastewater treatment plant. It is proposed that the isolates represent a new genus and species, Meganema perideroedes gen. nov., sp. nov. The type strain of Meganema perideroedes is strain Gr1(T) (=DSM 15528(T) =ATCC BAA-740(T)).