Studies have been carried out in detail on the lipid make up of Agro-bacterium tumefaciens using virulent agrocin-sensitive and avirulent agrocin-resistant strains. Phosphatidylcholine, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, and phosphatidylglycerol are the major phospholipids present in A. tumefaciens. Although the total lipid content is increased due to development of resistance towards agrocin, the proportion of phospholipids and neutral lipids in the total lipid fraction remains almost the same either in the normal or in the resistant strains. The relative proportion of most of the individual phospholipid and neutral lipid components also remains unaltered due to development of resistance towards agrocin. With the exception of the proportion of neutral lipid, those of total lipid and phospholipid decrease steadily with an increase in the age of the culture. It is further revealed that agrocin resistance brought about an increase in the amount of unsaturated fatty acids with concomitant decrease of saturated fatty acid content in A. tumefaciens as obtained by gas-liquid chromatographic analysis.
An attempt was made to elucidate whether any psychrophilic bacteria inhabited on the Hokkaido coast in winter, and consequently an obligately psychrophilic strain of bacteria was isolated from sea water several meters off shore in the suburbs of Abashiri city in Hokkaido. This strain resembled Vibrio marinus in many morphological and physiological properties. Optimum and maximum temperatures for growth were about 15° and below 25°, respectively. This psychrophile was also halophilic and required about 0.4M NaCl for the maximum growth. Furthermore, morphological change was observed in the cultures at 10°, 15°, and 20°, particularly in the young stage at 20°.
The process of oxidation of elemental sulfur by Thiobacillus thiooxidans involves at least two steps; an instant adhesion of bacterial cell to solid sulfur particles, and subsequent steady state sulfur oxidation by the cells attached to sulfur granules. Some properties of the first step, namely, sulfur-cell adhesion process, were elucidated as follows: 1) The process exhibited pH dependency which was identical to that in sulfur oxidation and an optimum pH was at 2-5. 2) Treatment of the cells with SH-binding reagents brought complete loss of adhesion ability and this blocking of adhesion was released by the addition of SH-donor. Consequently the thiol groups, which may exist in the cell envelope, must be essential for the adhesion process. 3) Both the adhesion ability and oxygen uptake activity were significantly affected in the presence of 2, 4-DNP, HOQNO, and some heavy metal chelators, and anoxia also had a fairly potent inhibitory action on the attachment of bacteria to solid sulfur particles. Therefore, the adhesion process must be energy-dependent.
The cell wall of "hiochi bacteria" was thicker than that of general lactic acid bacteria. Its thickness did not change in lag phase, and increased gradually in logarithmic phase, ceasing in stationary phase. Further, the higher the concentration of ethanol was in the medium, the thicker was the cell wall of growing organisms in it. As the pH of the medium approached the limit of bacterial growth, thickness of the cell wall became thinner.
The cellular fatty acid composition of 27 strains of gram-negative obligately anaerobic rods was determined by gas-liquid chromatography. Results showed that a variety of acids was detected in these organisms, and comparison of the relative amount of each of the acids was useful in distinguishing several species. A dendrogram based on their fatty acid composition was made, and this analysis appeared to be an aid in the grouping of the bacteria.
A new species of hydrogen-utilizing bacterium has been isolated from natural sources. This organism is Gram-negative, rod-shaped, 0.6×0.8-2.0μm in size, motile with peritrichous flagella. The content of guanine plus cytosine in the DNA of this organism is 70.2mol%. The organism is facultatively autotrophic. Carbohydrates are scarcely assimilated by this organism and only fructose is assimilated. Organic acids are assimilated well. Based on these distinctive characteristics, this hydrogen-utilizing bacterium has been named Alcaligenes hydrogenophilus sp. nov.