The patterns of cellular fatty acid and sugar composition of 17 strains representing 17 species of rumen bacteria were examined. They were roughly classified into four groups (A, B, C, and D) on the basis of the patterns of their cellular fatty acid composition. Group A had major amounts of even-numbered straight-chain fatty acids besides monounsaturated, 3-hydroxy, and odd-numbered straight-chain fatty acids. Group B had relatively large amounts of fatty aldehydes besides straight-chain saturated and monounsaturated fatty acids. Group C had large amounts of 3-hydroxy and monounsaturated fatty acids besides straight-chain saturated fatty acids. Group D had abundantly iso- and anteiso-methyl- branched fatty acids besides straight-chain saturated fatty acids and fatty aldehydes. The 17 strains of rumen bacteria varied slightly in their patterns of sugar composition mostly. The cells of 10 of the 17 strains contained mostly glucose. Analysis of the cellular fatty acid will help to gain insight into the bacterial community structure in the rumen.
The surface cultures of 19 myxomycete strains-17 associated with bacteria, and Physarum polycephalum and Symphytocarpus sp. as axenic ones-were investigated for their carboxymethylcellulose (CMC)-, pectin- and, for the first time, xylan-degrading capacities and their ability to destroy filter paper. Enzymatic activity was determined as the release of reducing sugars from the three carbohydrate substrates by "enzyme extracts" from the corresponding plasmodia; the destruction of filter paper was assessed optically. While CMC- and xylan-decomposing enzymes were found in all strains tested, only Stemonitis axifera could break down highly esterified pectin. Axenic myxomycetes lacked pectinase and C1-cellulase, since pectinolysis and degradation of filter paper ("native" cellulose) occurred only with myxomycetes "associated" with bacteria. The problem of working with non-axenic myxomycetes is discussed.
The acylase of Malbranchea was active against both benzyl and phenoxymethyl penicillin but the former was a poor substrate. The pH, temperature and reaction time optima were 8.0, 37°C and 5hr respectively. Immobilized dry cells retained activity up to 90 days. Cells were maintained for 40 days with good reuse efficiency until the 10th cycle; during this period, the 6-APA level dropped from 0.4 to 0.05mg/ml.
Reverse transcriptase sequencing of 16S ribosomal ribonucleic acids of some representatives of the genus Rhodococcus were performed in an attempt to clarify their intra- and inter-generic relationships. The results indicate that the genus Rhodococcus as presently constituted is phylogenetically heterogeneous. On the basis of the 16S ribosomal-RNA sequence and earlier chemical data it is proposed that the genus Gordona (Tsukamura) be revived to accommodate those rhodococcal species containing relatively long-chain mycolic acids (48 to 66 carbon atoms) and MK-9(H2) as the predominant menaquinone type.
The quantitative growth characteristics of the soil oligotrophic bacterium Agromonas oligotrophica JCM 1494 on diluted nutrient broth were investigated. The growth of the bacterium was totally inhibited in full strength nutrient broth (NB) but was supported in serially diluted NB of NB/10, NB/100, NB/1, 000, and NB/10, 000 with varied specific growth rates (k, 1/hr) of 0.102, 0.156, 0.117, and 0.089, respectively. The Ksvalue for NB was estimated to be NB/17, 500 or 0.46mg as organic carbon/ml. A yield value of 1.48×109 colony-forming unit mg of organic carbon was also calculated from the maximum growth yield analysis. From these results the oligotrophic nature of the bacterium was compared to those of other known oligotrophic bacteria.
We have studied the respiratory characteristics in the growing and the We have studied the respiratory characteristics in the growing and the rWe have studied the respiratory characteristics in the growing and the resting cells in the soil oligotrophic bacterium Agromonas oligotrophica JCM 1494 and the aquatic oligotroph Aeromonas hydrophila 315. The growth of A. oligotrophica on 1% trypticase peptone plus 0.1% yeast extract medium (TY) was biphasic. The molar growth yield on oxygen consumed (YO2, g of cell dry weight/mol O2) in the first phase increased 1.7-fold in the second phase. In the growth of A. hydrophila, YO2 nearly doubled with shifting from TY to 10-fold diluted TY (TY/10). These two cases of significant YO2 increase may indicate the operation of an efficient energetic regulation of the respiratory system apparently in response to changing cell density and medium nutrient levels. The studies of in vitro respiration with resting cells on a single substrate (low organic acids) revealed rather higher Km values for A. oligotrophica and A. hydrophila than for Escherichia coli K12 as a reference strain. But the apparent Km of A. oligotrophica for TY as a complex respiratory substrate was definitely lower than that with E. coli K12. This suggests a unique simultaneous uptake for multiple substrates. In A. oligotrophica cells, a-, b-, and c-type cytochromes and a CO-binding b-type cytochrome (assumed to be cytochrome o) were identified. But the a type was not detected in A. hydrophila cells. These cytochrome patterns in the two strains, described in oligotrophs for the first time, were not detestably changed by medium dilution, and there appears to be a sequence leading to cytochrome o in the aerobic electron transfer in both strains.
The membrane proteins MP32 and MP18 (molecular weights 32, 000 and 18, 000) increased extensively during sporulation in the mpo-1 mutant of Bacillus subtilis. Pulse-labeling experiments suggested that the increase in MP32 and MP18 during sporulation was due to the promoted de novo synthesis of these proteins. Neither spo0 mutations, nor the release from catabolite repression, affected the increase in MP32 and MP18 during sporulation. To clarify the relationship between the mpo mutation and the synthesis of MP32 and MP18, a mpo+/mpo-1 hetero merodiploid strain was constructed using the trpE26 mutation. In this strain, there was no overproduction of MP32 or MP18, indicating that the mpo+ is dominant to mpo-1, and that the mpo gene product may regulate negatively the synthesis of MP32 and MP18.
The NAD(P)+-specific glutamate dehydrogenase (GDH) in the strictly anaerobic bacterium Bacteroides fragilis is reversibly inactivated depending on ammonia concentrations in the culture (YAMAMOTO et al., J. Gen. Microbiol., 133, 2773 (1987)). A high-activity form of GDH was purified to homogeneity from B. fragilis grown on 1mM ammonia, and a low-activity form from the cells exposed to 50mM ammonia immediately before harvesting the ammonia-limited culture. The specific activities of the high- and low-activity forms were respectively 32.3 and 5.9 μmol/min/mg protein in NADP+-dependent deamination. The molecular weight of each form of GDH was 290, 000 daltons. The weight of the subunit was 49, 000 daltons. The isoelectric point was pH 4.5 in each form of GDH. There was no difference in the amino acid composition of the two forms. The optimum pH and the Km values for ammonia, 2- oxoglutarate, and L-glutamate were almost the same in the two forms of GDH. The two GDHs had different affinities for coenzymes; the Km values for coenzymes were slightly different in the two forms, and they were eluted by NaCl at different concentrations in affinity chromatography on Reactive red-agarose.
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