Zentralblatt für Bakteriologie Mikrobiologie und Hygiene: I. Abt. Originale C: Allgemeine, angewandte und ?kologische Mikrobiologie最新文献

Bacteroides hypermegas (Harrison and Hansen) differs to such an extent from the type species of Bacteroides, Bacteroides fragilis (Veillon and Zuber), that it cannot be retained in this genus. On the basis of morphological, biochemical and chemical criteria it is suggested that Bacteroides hypermegas be reclassified in a new genus, Megamonas, as Megamonas hypermegas (Harrison and Hansen) comb. nov.

Ribosomal subunits from five methanogenic bacteria were purified and their protein composition analyzed by gel electrophoretic methods. 30S and 50S subunits from the three Methanobacteriales species studied (Methanobacterium thermoautotrophicum, Methanobacterium bryantii, Methanobrevibacter arboriphilus) and also from Methanospirillum hungatei contained the typical “eubacterial” number of proteins whereas the protein composition of the Methanococcus vannielii ribosome seemed to be more complex. A tentative nomenclature was proposed for the ribosomal proteins from Methanococcus.

Cell wall preparations were obtained from 4 batches of Prochloron isolated from 4 different species of ascidians. All preparations contained the typical murein components, glutamic acid, alanine, meso-diaminopimelic acid, glucosamine and muramic acid. Their molar ratios as well as the ‘fingerprints’ of partial acid hydrolysates and the results of dinitrophenylation indicate strongly that the murein of Prochloron belongs to the variation Alγ (mDpm direct type) described by Schleifer and Kandler (1972).

Chemical and phenetic data indicate a close relationship between Bacterionema matruchotii (Mendel) and representatives of the genus Corynebacterium (Lehmann and Neumann). It is suggested that Bacterionema matruchotii be reclassified in the genus Corynebacterium, as Corynebacterium matruchotii comb. nov.

Ten endospore-forming, aerobic strains were isolated from pasteurized soil samples by enrichment at 32 °C in a minimal medium containing crotonate, phenylacetate or 2,3-butanediol as sole carbon and energy source. They are rods with a diameter greater than 1 μm, Gram variable, very motile, and peritrichous. The endospores are oval and non-deforming, thus placing the strains in the first morphological group of the genus Bacillus. Poly-β-hydroxybutyrate is not produced in appreciable quantities. The maximum growth temperature is between 48°C and 60°C. They neither ferment glucose nor use nitrate as an electron acceptor. The oxidase reaction is positive. They hydrolyze gelatin and “Tween 80”. All the strains use 23 compounds as sources of carbon and energy. Many characters vary from one strain to another. The average guanine + cytosine content of the DNA is 54.9 ± 1.4mol%. The 10 cultures described differ clearly from Bacillus megaterium and perhaps represent a large new mesophilic, thermotolerant, omnivorous species, sensu Stanier (1976).

The toxicity of cadmium (Cd) to fungi decreased as the concentration of chloride (Cl⁻) or of seawater was increased, indicating the lower toxicity of Cd-Cl complexes than of Cd²⁺. As chlorinity affects the speciation of Cd and its toxicity, the toxicity of Cd can be expected to differ in freshwaters, estuaries, and seawaters. Thus, abiotic factors, such as chlorinity, must be considered when establishing water quality criteria and standards for Cd.

The potential of smoked mullet as a vector of selected pathogenic bacteria was investigated. Two temperature studies were performed by bringing the internal temperature of the mullet to 74 C or 82 C for thirty minutes. Each temperature study included a light and heavy smoke treatment. Mullet were inoculated on the smoked surface with Vibrio parahaemolyticus, entrropathogenic Escherichia coli (0111:B4) and Staphylococcus aureus. During storage at 25 C the test organisms multiplied from 10³ to up to 10⁹ organisms/g within one week. A slightly reduced rate of growth occurred on those samples cooked at a higher temperature or treated with heavy smoke. Growth of the test organisms was prevented by storage for 10 days at 5 C.

Evidence is presented for a new heat-stable cofactor that is required for carbon dioxide reduction to methane by extracts of Methanobacterium thermoautotrophicum. This carbon dioxide reduction factor (CDR factor) is present in certain fractions of cell extract eluted from a DEAE-cellulose ion exchange column. The factor is required for reactions that involve methanogenic C₁ intermediates more oxidized than formaldehyde.

DNA dependent RNA polymerases from archaebacteria are complex molecules made up of 9 to 11 components yielding characteristic patterns in SDS Polyacrylamid gel electrophoresis. All components except one, in few cases two, of the smallest, are present but once per enzyme monomer.

DNA dependent RNA polymerases of archaebacteria differ from those of eubacteria in their complexity, their composition and thus their subunit patterns. They resemble each other and those of eukaryotes, especially yeast RNA polymerase A (I) in these respects.

All archaebacterial RNA polymerases are completely insensitive to rifampicin, streptolydigin and α amanitin.

They are stimulated by the alkaloid silybin which selectively enhances transcription by eukaryotic RNA polymerase A (I).

First results concerning the function of their components and some aspects of the transcription by these enzymes are discussed. Implications of the comparative analysis of RNA polymerase structure for taxonomic purposes are described.

The general properties of the archaebacterial ribosomes and the data available on the structure of both the ribosomal proteins and ribosomal RNA from the 5S RNA-protein domain and the ribosome “A” protein domain clearly support the concept that the archae-bacteria are a phylogenetic group quite distinct from either eucaryotes or eubacteria. The studies also indicate that some, at least, of the ribosomal components in the nuclear-cytoplasm of eucaryotes arose from an archaebacterial source.