THE METABOLISM OF VALERATE-3-C14 AND -5-C14 BY WHEAT STEM RUST UREDOSPORES

Uredospores of wheat stem rust took up about 90% of the carbon-14 present either as valerate-3-C14 or as valerate-5-C14 in M/30 phosphate buffer pH 6.2 in 3 hours. The initial valerate concentration was 0.017 mM and spores were supplied at the rate of 250 mg/30 ml of buffer. Carbon 3 of the valerate was largely respired as carbon dioxide but carbon 5 was extensively incorporated into spore components. Free amino acids contained about 40% of the radioactivity in the spores labelled with valerate-5-C14 and glutamic acid was highly labelled. Carbon 1 contained 8.1% and carbon 5, 3.8% of the carbon-14 in this glutamic acid and thus internal carbons contained 88%. The results with valerate-3-C14 and with valerate-5-C14 compare well with those of experiments done earlier with propionate-1-C14 and propionate-3-C14 respectively. It is concluded that propionate is formed from carbons 3, 4, and 5 of valerate, and thus that carbon 3 is converted to carbon dioxide, and carbons 4 and 5 to the carboxyl and methyl groups respectively of acetate.

FINE STRUCTURE OF BASIDIOSPORES OF SCHIZOPHYLLUM COMMUNE

Voelz, Herbert (University of West Virginia, Morgantown), and Donald J. Niederpruem. Fine structure of basidiospores of Schizophyllum commune. J. Bacteriol. 88:1497-1502. 1964.-The fine structure of basidiospores of the wood-rotting mushroom Schizophyllum commune was elucidated. Ungerminated spores were characterized by a fibrous cell wall, a cytoplasmic membrane, electron-dense granules, nuclei surrounded by nuclear envelopes with pores, and poorly defined mitochondria. Young germlings were still binucleate, whereas mitochondria appeared highly organized. Vacuolization appeared with germination, and elaborate pore structures were associated with septa.

STIMULATION OF CAROTENOGENESIS BY MICROBIAL CELLS

Spent mycelia of Blakeslea trispora recovered from a previous fermentation enhanced carotene production by mated cultures of the same organism. Peak yields of 107 to 142 mg of carotene per 100 ml of medium were achieved in 6 days. beta-Carotene constituted 92% of the total carotenoids produced. The enhancing substance was found present in an aqueous extract of the mycelium. Part of its activity was due to an organic acid fraction. Other microbial cells, molds, yeasts, and bacteria were also capable of enhancing carotene production.

POLYOL METABOLISM IN THE BASIDIOMYCETE SCHIZOPHYLLUM COMMUNE

Niederpruem, Donald J. (Indiana University Medical Center, Indianapolis), Amtul Hafiz, and Lyle Henry. Polyol metabolism in the basidiomycete Schizophyllum commune. J. Bacteriol. 89:954-959. 1965.-The polyol metabolism of intact cells and extracts of the wood-rotting mushroom Schizophyllum commune was investigated during the developmental cycle. Exogenous polyols stimulated the cellular respiration of germlings, but were without effect on that of ungerminated basidiospores. Requisite enzymes of polyol metabolism were demonstrated in extracts of spores and of subsequent stages of development. Oxidation of mannitol and sorbitol appeared to be coupled to nicotinamide adenine dinucleotide (NAD) reduction and was favored in alkaline medium. Ketohexose formation was shown during mannitol oxidation, and the NAD-dependent oxidation of xylitol yielded ketopentose. Xylitol oxidation with nicotinamide adenine dinucleotide phosphate (NADP) as hydrogen acceptor led to pentose formation. Oxidation of reduced NAD was enhanced by fructose but not by sorbose. Reduction of aldohexose and pentose was dependent upon reduced NADP, and pentose reductase was maximal at pH 6.8. The specific activity of mannitol dehydrogenase was highest in extracts of vegetative mycelium. Growth in either glucose or xylose media had no significant effect on enzymes of polyol metabolism.

EFFECTS OF PHYSIOLOGICALLY ACTIVE CHEMICALS AND ANTIBIOTICS ON LIGHT EMISSION BY THREE BASIDIOMYCETES

The effects of the antibiotics Streptomycin sulfate, Mycostatin, Viomycin, Acti-dione, Chloromycetin, Bacitracin, and Penicillin G on the light emission of several luminescent basidiomycetes have been analyzed. Also studied were the effects of 2,4-dinitrophenol, caffeine, and nicotine on the metabolic pathways involved in the bioluminescent reaction. Acti-dione was the most fungicidal antibiotic while Chloromycetin was the most effective fungistatic agent. Neomycin sulfate and Penicillin G were ineffective.

INDUCED MITOTIC CROSSING-OVER IN RELATION TO GENETIC REPLICATION IN SYNCHRONOUSLY DIVIDING CELLS OF USTILAGO MAYDIS

A method is now available for synchronizing the division of populations of cells of the smut fungusUstilago maydis. In two experiments carried out with a diploid strain heterozygous for several biochemical markers, samples of cells were removed at intervals through the synchronized division cycle and treated with a constant dose of ultra-violet light. Cell survival and the frequency of the various recombinants resulting from induced mitotic crossing-over were recorded. In addition the period of DNA synthesis in the unirradiated population has been measured. During this period the cells are very sensitive to ultra-violet light and those that survive contain the highest proportion of induced recombinants. In so far as the markers make it possible to locate the position of cross-overs, cells which are irradiated early in the period of genetic replication show most crossing-over towards the ends of the chromosome arms, whilst cells which are treated late in this period show crossing-over near the centromeres. The data are most easily interpreted by supposing that chromosome replication begins at the ends of the arms and proceeds to the centromere, and that the temporary interruption of this process by ultra-violet light can result in pairing and crossing-over in the vicinity of the points of interruption.

SURVIVAL OF SINGLE-BASIDIOSPORE ISOLATES OF RHIZOCTONIA PRATICOLA AND RHIZOCTONIA SOLANI

Twenty randomly selected single-basidiospore isolates from each of Rhizoctonia praticola and R. solani differed considerably in their tolerance to CO2, competitive saprophytic activity, and ability to survive within precolonized substrate segments incubated in soils with or without pentachloronitrobenzene (PCNB) or oat straw. With a few exceptions, isolates possessing high saprophytic activity also possessed high tolerance to CO2 and high surviving ability in precolonized substrate. Several single-spore isolates of R. solani possessed higher ability for saprophytic survival in organic matter and lower CO2-sensitivity than their parent culture. Survival of single-basidiospore isolates in precolonized substrate segments was greater in unamended soil or soil amended with oat straw than in soil treated with PCNB. Mature oat straw reduced surviving ability of several isolates, whereas it increased surviving ability of others above that observed in unamended soil. The isolates whose surviving ability was increased by oat straw were mostly those possessing high saprophytic activity in unamended soil. Saprophytic activity and virulence of all isolates tested declined with time. Rate of decline of virulence was much more rapid for weak than strong saprophytes.

PRODUCTION OF FUNGAL MYCELIAL PROTEIN IN SUBMERGED CULTURE OF SOYBEAN WHEY

Various soybean whey media were tested as substrate for seven species of fungi in submerged culture. Very little mycelial growth was obtained with Morchella hybrida, Collybia velutipes, Cantharellus cibarius, and Xylaria polymorpha. Agaricus campestris failed to grow. Tricholoma nudum and Boletus indecisus showed the greatest rate of growth and production of mycelial protein and the best utilization of soybean whey solids, with much shorter incubation times compared with those of the other species. T. nudum developed as spheres having diameters of about 5 to 8 mm, instead of the usual slurry or yeastlike form, in the presence of added ammonium acetate. B. indecisus always developed as spheres. Mycelial yields and production of protein by T. nudum greatly decreased with the addition of more than 1% glucose to soybean whey, whereas with B. indecisus the yield of protein almost doubled when up to 3% glucose was added. The effect of minerals on mycelial growth was determined. With soybean whey concentrated to 50%, the rate of mycelial growth of T. nudum was nearly doubled, but protein content of mycelia was greatly reduced. Mycelial growth and yield of protein of B. indecisus grown in concentrated whey were increased greatly. About 4 to 6 g of mycelial protein per liter can be obtained from fermentation in soybean whey, depending upon the medium used. Utilization of soybean whey by fungal fermentation may have economic value in whey disposal and in the production of products of high protein content.

Transformations of progesterone by basidiomycetes

A total of 254 basidiomycete cultures have been examined for their action on progesterone. Of these, 54 showed transformation products by thin-film and gas-liquid chromatography. The major product formed by eight of these organisms acting on progesterone has been isolated and identified.