The cellular fatty acids of 88 bacterial isolates were analyzed, including 46 strains which did not grow on full-strength nutrient broth (NB) but grew on its 100-fold dilution (DNB organisms) and 42 strains which grew on both NB and its 100-fold dilution (NB organisms). All strains were grouped into 14 clusters according to their fatty acid composition, using average linkage cluster analysis and similarity values based on correlation coefficients. Among these 14 clusters, five comprised only DNB organisms and six comprised NB organisms. In the remaining three clusters, DNB organisms and NB organisms were not segregated with respect to similarity values based on their fatty acid composition, but were distinguished on the basis of other bacteriological characteristics such as quinone systems, cell morphology, or other physiological characteristics.
The phase separation of total phospholipids and four individual phospholipids from a psychrophilic bacterium, Vibrio sp. strain ABE-1 (Vibrio ABE-1), was examined with methyl-9, 11, 13, 15-all-trans-octadecatetraenoate (methyl-t-parinarate) as a fluorescent probe. Phase separation of total phospholipids from the inner and outer membranes always occur at temperatures lower than the respective growth temperatures (0°C, 10°C, or 20°C). Moreover, in both inner and outer membrane phospholipids, fluorescence anisotropies calculated from polarization ratios were strikingly similar to one another when they were analyzed at the same temperatures as the respective growth temperatures. These results show that Vibrio ABE-1 can keep their membranes fluid state at least in the temperature range from 0°C to 20°C. Preservation of the membrane fluidity at low temperature seems to be attributable in this bacterium to an extremely high content of hexadecenoic acid (16:1) in the membrane phospholipids, especially in phosphatidyl ethanolamine and phosphatidyl glycerol.
We analyzed a previously unknown phospholipid (PL-2) in the psychrophilic bacterium, Vibrio ABE-1 . In thin-layer chromatography, it moved close to phosphatidylethanolamine but had a different Rf value. The polar head group of PL-2 was ethanolamine, and the sn-glycerol carbon atoms. This demonstrates that PL-2 is a species of phosphatidyl- bond/ethanolamine was 1:1.1:2.0:1.1. The chloroform- and water- soluble fractions after treatment with phospholipase C were 1, 2-diacylglycerol and phosphoryl ethanolamine, respectively. The phosphatidylethanolamine of this bacterium has mainly C16 fatty acids especially hexade- cenoic acid (16:1). PL-2 has higher amounts of saturated fatty acids such as hexadecanoic acid (16:0) and short chain fatty acids with less than 15 carbon atoms. This demonstrates that PL-2 is a species of phosphatidylethanolamine which has fatty acids that are different in average chain length and degree of unsaturation. The possible role of PL-2 in the phase separation of membrane phospholipid is discussed.
Studies of the trophic relationships in microbial reduction of sulfate established the need for three physiological types of organisms: cellulose- digesters (Cellulomonas, Cytophaga or Micromonospora), a lactic acid fermenter (Enterobacter), and a sulfate reducer (Desulfovibrio). Microcosms based on cellulose mineral salts medium were inoculated with varying combinations of mixed cultures and incubated at 30°C for 18 days. The extent of sulfate reduction varied in the microcosms. A 5- member culture which contained the three cellulolytic organisms reduced the most sulfate (52%). Cellulomonas was the most efficient cellulolytic partner. Unless all three physiological types were present, sulfate was not reduced.
A non-saccharified high stress corn mash system was used to study the acceleration of glycolysis in glucose ethanol fermentation by Saccharomycescerevisiae. It was found that the controlled addition of ammonium sulfate or ammonium chloride resulted in an accelerated glycolytic rate, independent of the final ethanol yield. Adding high levels of ammonium salt, however, resulted in decreased extracellular pH and delayed cessation of fermentation. The delayed cessation of ethanol production was due to the decrease in extracellular pH, which could be controlled by the addition of citrate buffer.
Microbial metabolism of polychlorinated phenoxy phenols (PCPPs) and polychlorinated phenoxy anisoles (PCPAs) was studied in mixed and pure bacterial cultures and in PCPP-contaminated soil. Both in the laboratory and in the field the PCPPs with a hydroxyl group in the para position in the molecule were methylated faster than those with a hydroxyl group in the ortho position. Rhodococcus chlorophenolicus, a polychlorophenol mineralizer, methylated 40% of one PCPP compound in 7 days, given in a concentration of 10ppm. The methylation was aerobic. There was no further metabolism of PCPAs. One of the PCPA-compounds was also o- demethylated by R. chlorophenolicus. In chlorophenol-contaminated soil each of the 8 PCPPs contained in a technical chlorophenol product became methylated.
Water-soluble polysaccharides of fast-growing Rhizobia strains were produced in three conditions of biosynthesis: cells growing in a yeast extract medium, cells growing in a mineral medium and cells resting. Under these three conditions, three strains of Rhizobium leguminosarum (L 1S, L2S, L3S), three strains of Rhizobium phaseoli (P2S, P7S, P8S), and two strains of Rhizobium trifolii (T7S, T15S) produced polysaccharides which were precipitated with one volume of ethanol and purified. These polysaccharides contained (in % w/w): glucose (51.7-64.8), galactose (8.9-14.7), glucuronic acid (14-23), and some pyruvic and acetic acids which varied with the conditions of polysaccharide production. The polysaccharides produced in the conditions cited above, by four strains of Rhizobiummeliloti (M5N1, M11S, M1-5, L5-30) differed from those of R. leguminosarum, R. phaseoli, and R. trifolii. The polysaccharides of R. meliloti contained (in% w/w): glucose (63.7-74), galactose (8.2-11), no glucuronic acid (except for R. meliloti M11S: 1%) and some pyruvic, acetic and succinic acids which varied with the conditions of polysaccharide biosynthesis.
The effect of nitrate on the level of superoxide dismutase (SOD) in aerobically or anaerobically grown Escherichia coli was examined. The addition of nitrate did not influence the SOD level in aerobically grown E. coli cells. When E. coli was cultured anaerobically, the cells grown without nitrate contained only iron-containing SOD (Fe SOD), but the cells grown with nitrate contained, in addition to the Fe SOD, manganese- containing SOD (Mn SOD) and a SOD with a protein moiety which is a hybrid between Fe SOD and Mn SOD (hybrid SOD). The total level of SOD in cells grown anaerobically with 20 or 40mM nitrate was three- to fourfold higher than the level in cells grown without nitrate. Adding tungstate during anaerobic culture with nitrate repressed the formation of Mn SOD and hybrid SOD. Nitrate did not affect the level of SOD in anaerobically grown E. coli mutants deficient in nitrate reductase. Adding nitrite during anaerobic culture did not increase the level of SOD in E. coli cells. These results show that the operation of the nitrate respiration system induced the formation of Mn SOD and hybrid SOD.