New psychrophilic and psychrotolerant Bacillus marinus strains from tropical and polar deep-sea sediments and emended description of the species.

In contrast to the current view that psychrophily combined with an absolute requirement for NaCl is connected with the Gram-negative cell wall type, psychrophilic and psychrotolerant, NaCl-requiring, Gram-positive bacteria have been isolated from tropical Atlantic, Arctic and Antarctic deep-sea sediments. Some of the isolates are even extremely psychrophilic, having maximum growth temperatures of 4 degrees C. On the basis of phenotypic characteristics, DNA base analyses, DNA-DNA hybridizations and partial and complete 16S rRNA gene sequence analyses, the strains from the three distinct geographical regions have been allocated to the obligately marine species Bacillus marinus. The distribution and origin of B. marinus are discussed and an emended description of the species is presented.

Evolution of arginine biosynthesis in the bacterial domain: novel gene-enzyme relationships from psychrophilic Moritella strains (Vibrionaceae) and evolutionary significance of N-alpha-acetyl ornithinase.

In the arginine biosynthetic pathway of the vast majority of prokaryotes, the formation of ornithine is catalyzed by an enzyme transferring the acetyl group of N-alpha-acetylornithine to glutamate (ornithine acetyltransferase [OATase]) (argJ encoded). Only two exceptions had been reported-the Enterobacteriaceae and Myxococcus xanthus (members of the gamma and delta groups of the class Proteobacteria, respectively)-in which ornithine is produced from N-alpha-acetylornithine by a deacylase, acetylornithinase (AOase) (argE encoded). We have investigated the gene-enzyme relationship in the arginine regulons of two psychrophilic Moritella strains belonging to the Vibrionaceae, a family phylogenetically related to the Enterobacteriaceae. Most of the arg genes were found to be clustered in one continuous sequence divergently transcribed in two wings, argE and argCBFGH(A) ["H(A)" indicates that the argininosuccinase gene consists of a part homologous to known argH sequences and of a 3' extension able to complement an Escherichia coli mutant deficient in the argA gene, encoding N-alpha-acetylglutamate synthetase, the first enzyme committed to the pathway]. Phylogenetic evidence suggests that this new clustering pattern arose in an ancestor common to Vibrionaceae and Enterobacteriaceae, where OATase was lost and replaced by a deacylase. The AOase and ornithine carbamoyltransferase of these psychrophilic strains both display distinctly cold-adapted activity profiles, providing the first cold-active examples of such enzymes.

Marine star-shaped-aggregate-forming bacteria: Agrobacterium atlanticum sp. nov.; Agrobacterium meteori sp. nov.; Agrobacterium ferrugineum sp. nov., nom. rev.; Agrobacterium gelatinovorum sp. nov., nom. rev.; and Agrobacterium stellulatum sp. nov., nom. rev.

Two new species of aerobic, gram-negative, peritrichously flagellated or nonmotile marine bacteria usually forming star-shaped aggregates were isolated from northeastern Atlantic Ocean bottom sediments. These organisms resembled eight star-shaped-aggregate-forming bacterial species from the Baltic Sea originally ascribed to the genus Agrobacterium but not included on the Approved Lists of Bacterial Names because of their questionable relationships to true agrobacteria. These two sets of star-shaped-aggregate-forming bacteria were compared by means of phenotypic data, DNA base compositions, DNA-DNA relatedness, and one-dimensional electrophoretic analysis of low-molecular-weight RNAs (5S rRNA and tRNA). According to the results of genotyping, the northeastern Atlantic Ocean isolates and three of the Baltic Sea species formed a group of closely related bacteria that could not be excluded from the genus Agrobacterium with certainty. Until more genotypic data are available, these five marine species are regarded as a distinct subdivision of the genus Agrobacterium consisting of Agrobacterium atlanticum sp. nov. (type strain, 1480T = DSM 5823T), A. meteori sp. nov. (type strain, 1513T = DSM 5824T), A. ferrugineum sp. nov. nom. rev. emend. (type strain, ATCC 25652T), A. gelatinovorum sp. nov. nom. rev. emend. (type strain, ATCC 25655T), and A. stellulatum sp. nov. nom. rev. emend. (type strain, ATCC 15215T). "A. aggregatum" proved to be a later subjective synonym of A. stellulatum, which had priority. The remaining four Baltic Sea species, "A. agile," "A. kieliense," "A. luteum," and "A. sanguineum," could not be placed in the new subdivision of Agrobacterium.

[A simple and fast enzyme immunoassay for the quantitative determination of C-reactive protein]. / Ein einfacher und schneller Enzymimmunoassay zur quantitativen Bestimmung des C-reaktiven Proteins.

The principle is based on the competitive binding of the enzyme-labelled CRP (enzyme: alkaline phosphatase) and the serum CRP to solid phase-bound antibodies. The detection limit was 10 micrograms/l. The precision in the series in the border-line "normal" to "pathological" (5 mg/l) was 2.9%; the precision from day to day at the concentration of 5 mg/l was 4.5%. Only 2 h are required for the whole test.

DNA base compositions of halophilic and nonhalophilicBacillus firmus strains of marine origin.

The mineral salt requirements of 27 strains ofBacillus firmus were determined. Twenty-six of these strains were of marine origin and one terrestrial strain was used as a reference. Three strains demonstrated strictly halophilic behavior, i.e., they showed no growth in media prepared without sodium chloride. Seven strains were nonhalophilic. The growth of 17 strains was stimulated by the addition of sodium chloride, but the cells were able to grow without it. These results were compared with the DNA base compositions of the strains. In contrast to literature data, relationships between the DNA base ratios and the halophilic or nonhalophilic behavior of the cells could not be detected. But strains with guanine plus cytosine values above 41 mol% did grow well at 44°C, and those strains showing poor growth at this temperature had lower guanine plus cytosine percentages.

NMR and calorimetric studies of changes in phase transition of head group modified phospholipids.

The 13C- and 31P-NMR spectra and DSC thermograms of unsonicated dispersions consisting of phospholipids of varying methylation stages of the propanolamine head group were investigated. Methylation of the head group was accompanied by a corresponding reduction in the phase transition temperatures. In the liquid crystalline state the 31P-anisotropy of the chemical shift is about equal for all studied compounds, demonstrating that the motion of the phosphate group is not influenced by modifications of the propanolamine group.