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Abstract: Electron microscope studies were made of wall regeneration byPythium protoplasts. Wall regeneration began with the formation of a loose network of fibrils on the surface of the protoplast followed by increase in density of the fibrillar mesh and deposition of granular matrix material. The majority of the protoplasts did not develop beyond the loose fibrillar network stage, however a small percentage were able to complete wall formation and to form hyphal tubes. A clear zone of demarcation was visible between the fibrillar surface of the protoplast and the smooth surface at the base of the developing hyphal tube.

The study of the atmosphere and climate of Mars will soon be advanced considerably by the Mars Observer mission. This paper describes the atmospheric sounder for this mission and how it will measure key Martian atmospheric parameters using IR gas correlation and filter radiometry. The instrument now under development will provide high-resolution vertical profiles of atmospheric temperature, pressure, water vapor, dust, and clouds using limb sounding techniques as well as nadir observations of surface thermal properties and polar radiative balance.

A water-soluble compound formed by Ustilagosp. (PRL 627) in aerobic, submerged culture has been identified as D-mannopyranosyl-1-meso-erythritol. The extracellular "oil" produced at the same time by this fungus contains D-mannose, meso-erythritol, acetic acid, and a number of saturated and unsaturated fatty acids, probably as a mixture of D-mannosido-meso-erythritol residues to which the various acids are joined by ester linkages.

L-Erythrulose-1-C14and -4-C14were used as precursors in the biosynthesis of 4-O-β-D-mannopyranosyl-D-erythritol. The ketose was utilized efficiently and the C14distribution pattern in the product indicated that the 4-carbon fragment was transferred intact to C-3, C-4, C-5, and C-6 of the mannose moiety and was also reduced intact to the erythritol portion.A method for the degradation of D-mannose for determination of the C14distribution in the molecule is described.

The β-cellobiolipid, ustilagic acid, deposited when Ustilago zeae(PRL 119) is grown in a medium containing glucose, was prepared from 1-C14-glucose. The labelled acid was degraded to carbohydrate and fatty acid fractions. The carbohydrate was shown to be synthesized from 3-C fragments and the fatty acid from 2-C fragments. These results show that the hexose metabolism of the organism is probably the same as that suggested in the Embden–Meyerhof scheme.

A water-soluble compound formed by Ustilagosp. (PRL 627) in aerobic, submerged culture has been identified as D-mannopyranosyl-1-meso-erythritol. The extracellular "oil" produced at the same time by this fungus contains D-mannose, meso-erythritol, acetic acid, and a number of saturated and unsaturated fatty acids, probably as a mixture of D-mannosido-meso-erythritol residues to which the various acids are joined by ester linkages.

The β-cellobiolipid, ustilagic acid, deposited when Ustilago zeae(PRL 119) is grown in a medium containing glucose, was prepared from 1-C14-glucose. The labelled acid was degraded to carbohydrate and fatty acid fractions. The carbohydrate was shown to be synthesized from 3-C fragments and the fatty acid from 2-C fragments. These results show that the hexose metabolism of the organism is probably the same as that suggested in the Embden–Meyerhof scheme.

D-Glucose-6-C14, D-erythrose-4-C14, and D-erythritol-4-C14were used as precursors in the biosynthesis of 4-O-β-D-mannopyranosyl erythritol by Ustilagosp. PRL 627 and the patterns of C14labelling in the products determined. The disaccharide appears to be formed by direct transformation of D-glucose to a D-mannose unit which is then attached to C-4 of D-erythritol.* The labelling of the D-erythritol † portion shows that 80% of C-4 of the molecule is derived from the 6-position of D-glucose.

L-Erythrulose-1-C14and -4-C14were used as precursors in the biosynthesis of 4-O-β-D-mannopyranosyl-D-erythritol. The ketose was utilized efficiently and the C14distribution pattern in the product indicated that the 4-carbon fragment was transferred intact to C-3, C-4, C-5, and C-6 of the mannose moiety and was also reduced intact to the erythritol portion.A method for the degradation of D-mannose for determination of the C14distribution in the molecule is described.

The needlelike crystals which form in aerated submerged cultures of the corn smut Ustilago zeae(PRL-119) were found to be a D-glucolipid, m.p. 146-7°C, (pyridine), which contained one carboxyl group, two ester groups, at least two terminal methyl groups, and two D-glucose residues per mole. On the basis of elementary analyses, neutralization equivalent, and molecular weight estimations, the molecular formula of the material isolated was approximately C37H62−6O17. The substance was not shown to be chemically homogeneous. Conditions used in culturing the fungus in stirred fermentors to produce the crystalline metabolic product, which was termed "ustilagic acid", are described, and a procedure for the isolation of the material is given.

Mycochrysone, an orange-red crystalline pigment, has been isolated from in vitro cultures of an inoperculate discomycetous fungus. It possesses quinonoid properties and forms a monoquinoxaline derivative. At least two phenolic or enolic groups are present, one of which is in the periposition to a quinone carbonyl. Reduction of the pigment with a zinc dust –zinc chloride mixture gives perylene, together with some hydroperylenes. The pigment shows limited antibiotic activity.

A new pigment, volucrisporin, has been isolated from shaken cultures of the Hyphomycete VolucrisporaaurantiacaHaskins, and characterized as 2,5-(m-hydroxyphenyl)-1,4-benzoquinone. The structure has been confirmed by synthesis of the dimethyl ether.

In experiments with C14-labelled compounds, shikimic acid, phenylalanine, phenyllactic acid, and metatyrosine were found to be precursors of the terphenylquinone pigment volucrisporin. It is suggested that the pigment is biosynthesized by the self-condensation of two molecules of an unbranched phenylpropanoid intermediate, and that hydroxylation of the phenyl rings in the meta position occurs before the condensation step.

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A new metabolite has been isolated from the fungus Monochaetiacompta. The properties and reactions of the metabolite suggest that it is 6,8a-dihydro-4-acetyl-8-methyl-6-oxo-7(3-methyl-2-oxo)-pentyl-1 H-2-benzopyran-1-one (2a).

A cellulase and a laminaranase have been purified from a Streptomyces lytic enzyme complex. Lipase and protease were separated from glucanases. A combination of the purified glucanases produced “protoplasts” fromPythiumsp. PRL 2142. Lipase was shown to act as an adjuvant in this process.A cellulase and a laminaranase have been purified from a Streptomyces lytic enzyme complex. Lipase and protease were separated from glucanases. A combination of the purified glucanases produced “protoplasts” fromPythiumsp. PRL 2142. Lipase was shown to act as an adjuvant in this process.

D-Glucose-6-C14, D-erythrose-4-C14, and D-erythritol-4-C14were used as precursors in the biosynthesis of 4-O-β-D-mannopyranosyl erythritol by Ustilagosp. PRL 627 and the patterns of C14labelling in the products determined. The disaccharide appears to be formed by direct transformation of D-glucose to a D-mannose unit which is then attached to C-4 of D-erythritol.* The labelling of the D-erythritol † portion shows that 80% of C-4 of the molecule is derived from the 6-position of D-glucose.

Seven commercial inhibitors of sterol biosynthesis were tested for their effect upon vegetative growth and sexuality in Pythium acanthicum and Zygorhynchus moelleri. Five compounds (SKF 525, Chlorpropamide, Tolbutamide, Benzmalacene, AY 9944) inhibited both growth and sexuality of both fungi and two (SKF 7732 and SKF 7997) were ineffective. Pythium was more sensitive to the activity of the inhibitors than was Zygorhynchus. None of the compounds tested inhibited sexuality without similarly reducing vegetative growth.

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YOUNG hyphae of filamentous fungi generally grow outward in a straight line from their point of origin in a colony. The branches of the hypha grow at a more or less acute angle to the parent hypha and in a forward-pointing direction. They never grow backwards into the colony except under unusual experimental conditions1. There are exceptions. The clamp connexions of the Basidiomycetes, on initiation, grow backwards, as may the fusion cell in crozier formation in the Ascomycetes. Another exception may be found among the mycelial strand-forming fungi such as Merulius lacrimans, where thigmotropically sensitive “tendril” hyphae may grow backwards (or forwards) along the wide main hyphae2.

A fungus of Pythiumspecies survives high and low temperatures longer when a suitable sterol is added to the growth medium.

m-Cresol has been isolated from culture filtrates of Valsa friesii.The yield after 10 days of growth on glucose-phytone broth was 160 mg/liter.