Michiharu Kobayashi

NITROGEN-FIXING MICROORGANISMS IN PADDY SOILS : V. : Nitrogen Fixation in Mixed Culture of Photosynthetic Bacteria (Rhodopseudomonas capsulatus species) with Other Heterotrophic Bacteria (1)

Abstract P. W. WILSON (1) reported that the contaminated culture of azotobacter was superior to the pure culture in the fixation of nitrogen. We (2) also reported that the nitrogen fixation by photosynthetic bacteria, Rhodopseudomonas capsulatus associated with various microorganisms was superior to that in the pure culture.

NITROGEN-FIXING MICROORGANISMS IN PADDY SOILS IV. : Nitrogen Fixation by Photosynthetic Bacteria (Rhodopseudomonas capsulatus species) under Various Conditions

Abstract In 1949, GEST and KAMEN (1,2) reported that Photosynthetic bacteria can fix molecular nitrogen. LINDSTROM et al. (3,4) tested the nitrogen fixing ability of five species of photosynthetic bacteria under the following four conditions; 1) anaerobic light, 2) aerobic light, 3) aerobic dark, 4) anaerobic dark. As the result of the experiment, they certified that it Was only under the anaerobic light condition that the bacteria can fix molecular nitrogen.

EFFECT OF THE APPLICATION OF LIGNIN AND/OR CHITIN TO SOIL INOCULATED WITH Fusarium oxysporum ON THE VARIATION OF SOIL MICROFLORA AND PLANT GROWTH

Effect of the application of organic materials to soil inoculated with Fusarium oxysporum on the variation of soil microflora was studied during three years. Plant cucumber was cultivated five times and the growth was analyzed statistically. Lignin and/or chitin were applied to soil at concentrations of 2,000 and 1,000 ppm, respectively. Fusarium oxysporum f.sp. cucumerinum (F.o.c.) was inoculated to the soil at a level of 109 propagules/pot. After cucumber, the host plant, had been cultivated five times during three years, the following results were obtained: 1) Chitin application increased the populations of fungi and actinomycetes and decreased the population of F.o.c. in the soil. 2) Lignin application inhibited the multiplication of fungi, induced the growth of a peculiar fungal flora and promoted the survival of F.o.c. in the soil and also masked the useful effect of chitin application. 3) Increase of F.o.c. population by host plant cultivations was not observed. Populations of F.o.c. decreased in a...

Destruction of fecal coliphages during the composting process of porcine feces

Abstract Application of sewage sludge to agricultural land has been a common practice for many years. There is, however, a potential hazard of pathogen spread through food and drinking water, since the pathogens concentrate in the sludge (JONES and WATKINS 1985; SHIMOHARA et al. 1985) and remain in the sludge for a long period of time (TIERNEY 1977). Anaerobic digestion of sludge destroys the indigenous pathogens owe to the high temperature generated by the microbial activity in the course of digestion (BERG and BERMAN 1980). However viruses have been recovered from sludges digested during a prolonged period of time at 37 or 50°C (LUND 1976). Anaerobic digestion of sludge is associated with health risks caused by virus spread.

BIOASSAY OF DECOMPOSED PRODUCTS OF RAPESEED CAKE USING Lemna paucicostata 6746

The effects of the water extracts of rapeseed cakes undergoing decomposition under different conditions on plant growth were evaluated using Lemna paucicostata 6746 for the bioassays. Half-strength Hutner’s medium was used as the basal medium, to which aliquots of concentrated water extracts were added in the ratio of 1/1,000, and the number of reproduced fronds were counted after 7 days as an index of the growth. Aerobic decomposition of rapeseed cake (1:1 ratio of rapeseed cake to water, w/w) showed a strong inhibitory effect on the growth of L. paucicostata 1 to 4 weeks after the start of the decomposition. In the submerged decomposition (1 : 10 ratio of rapeseed cake to water, w/w), no inhibition was detected in the first weeks, but a strong inhibition appeared after 8 weeks and increased thereafter. The water extracts of the rapeseed cake undergoing decomposition under the submerged condition contained large amounts of fatty acids (acetic, propionic, and butyric acid), which were considered to be the...

NITROGEN-FIXING MICROORGANISMS IN PADDY SOILS XII : Cell Wall of Rhodopseudomonas capsulatus and Azotobacter agilis (1)

Summary Introduction We have been studying the interrelation between R. capsulatus and other various microorganisms, in which there are symbiotic relationships (I). When R. capsulatlls and Az. vinelandii co-existed, molecular nitrogen was fixed much more than in each pure culture and many slime substances (polysaccharides, muco-polysaccharides etc.) were produced (2). In order to study symbiotic nitrogen fixation between the two microorganisms, first, the nature of the cell wall of both bacteria has to be known.