Japanese isolates of Verticillium dahliae were formerly designated as tomato pathotype and non-tomato pathotype by pathogenicity tests. We attempted to classify 18 Japanese isolates based on vegetative compatibility. Only three isolates of the tomato pathotype induced compatible alm-brm mutants. A non-secreting brm mutant was not induced from isolate of the non-tomato pathotype. Complementation was not achieved by a pair of mutants from the tomato pathotype and those from the non-tomato pathotype. From these results, Japanese isolates of V. dahliae could not be separated into any vegetative compatibility groups using melanin synthesis-deficient mutants.
Thirty-seven strains of aerobic bacteriochlorophyll (Bchl)-containing bacteria (ABB) isolated previously from the coasts of Australia were compared with the authentic ABB, Erthrobacter and Roseobacter. They were divided into four groups (GI-GIV) on the basis of cell color, absorption spectrum type of Bchl in the near infrared region and cell morphology. Furthermore, some members of GI and GII were separated genetically into 3 and 4 respectively based on the levels of DNA homology. Among the 37 strains tested, only strain OCh273, a strain of GIV, showed comparatively high DNA homologies (ca. 50%) with the type strains of Roseobacter spp., and the other 36 strains showed low DNA homologies (1 to 12%) with the type strains of Erythrobacter longus and Roseobacter spp. The ubiquinone system of all strains was Q-10 and the major cellular fatty acid (CFA) was C18:1 acid except in five strains. The major CFA in four (OCh208, OCh229, OCh246 and OCh268) of the five strains was C17:1 and that of the remaining strain (OCh492) was C16:0? The guanine plus cytosine contents of the DNA of the 37 test strains examined were from 53.0 to 74.8mol%.
In vitro rumen digestibility of five lignocellulosic materials (rice bran, ryegrass-hay, barley straw, birch and spruce sawdusts) were assessed before and after solid substrate fermentations with Coriolus versicolor, Pleurotus sajo-caju, Phanerochaete chrysosporium, Chaetomium cellulolyticum, and Trichoderma harzianum. In studies with spruce sawdust, marked reductions in gas and volatile acid production were observed after 4 days of simulated rumen fermentation. With the fermented sawdusts, increases in digestibility and daily carbon dioxide production were observed as the fermentation proceeded. Chitin and D(+)-glucosamine, major components of fungal cell walls enhanced digestibility, acetate output and total gas production except at concentrations >30% w/w chitin or >1% w/v glucosamine which gave adverse results. The presence of high levels of mycelial biomass observed visually in fungal fermented rice bran, hay and barley straw did not appear to enhance digestibility.
The enzyme alpha amylase was purified from cells of Nocardia asteroides by gel filtration on Sephadex G-150 and by DEAE-Sepharose column chromatography. The purified enzyme revealed a single band on a polyacrylamide gel electrophoresis under native conditions, indicating its homogeneity. The native molecular weight of the purified enzyme on a Sephadex G-200 column was estimated to be 150, 000. The enzyme showed two protein bands of molecular weights 65, 000 and 56, 000 on a 10% SDS-PAGE under denatured conditions, indicating that the native enzyme has two or more subunits of different molecular weights. The purified enzyme had an optimal pH of 6.9 and an optimal temperature of 50°C. The enzyme activity was enhanced by MgCl2 and inhibited by EDTA. Starch or maltose in the culture medium significantly enhanced the enzyme production compared with the culture medium containing glucose.
Two strains of the genus Debaryomyces, that are phenotypically and genetically close to D. polymorphus, were isolated from South African soils. Nuclear DNA comparison studies established that the two strains reassociate with the type strain of D. polymorphus for 49-59%. The two strains have consequently been assigned to the new variety D. polymorphus var. africanus which is practically distinguished from D. polymorphus var. polymorphus by the utilization of L-rhamnose.
Aeromonas hydrophila PC5, a soil isolate, produced amylase and protease on a variety of substrates. The highest titers of both enzymes were observed with casein at 20°C and at pH 7.0. Unlike amylase, the protease was thermostable and retained about 50% activity at 60°C after 120min of exposure. Of the metal ions tested, only protease was stimulated by 10 mM Fe+2. EDTA and iodoacetamide inhibited both of the enzymes. Partial purification with DEAE-cellulose revealed that the enzyme complex consists of an α-amylase, a β-amylase and a metalloprotease.
The cells of acidophilic iron-oxidizing bacteria (Thiobacillus ferrooxidans) were immobilized using five kinds of polymers (photo-crosslinkable resin, agar, calcium alginate, k-carrageenan, and gelrite) as gel matrix, and the characteristics of cell immobilization were revealed. Among these gels, gelrite showed promise for application in iron oxidation under strongly acidic conditions. In continuous cultures of iron-oxidizing bacteria immobilized in gelrite beads, a steady state of strong iron oxidation was maintained for a month. The thick layer of iron-oxide precipitates was formed around reddish-brown "activated beads" that harbored a large number of iron-oxidizing bacteria and were the sources of cells living in the liquid phase.