Inorganic sulfate enters the mycelia of Aspergillus nidulans, Penicillium chrysogenum, and Penicillium notatum by a temperature-, energy-, pH-, ionic strength-, and concentration-dependent transport system ("permease"). Yamamoto and Segel (17) described some of the characteristics of a sulfate transport system ("permease") in Penicillium chrysogenum. Preliminary evidence suggested that the permease was under metabolic control, but the mode of regulation and the identity of the effectors were not determined. While that work was in progress, Scott and Spencer (8) The present work was undertaken in order to determine the mode of regulation of the sulfate permease in filamentous fungi, and also to determine whether the differences between the A. nidulans and P. chrysogenum permeases are as marked as reported. MATERIALS AND METHODSStrains of Fungi. The organisms used for this study were Penicillium chrysogenum, strain PS-75 (wild-type), Penicillium notatum, strain CMI-38632, hereafter called 38632M (a white-spored mutant lacking sulfate permease and at least one of the sulfateactivating enzymes), and strain CMI-38632R (a sulfate permeasepositive revertant isolated in our laboratory from strain 38632M), Aspergillus nidulans (wild-type), strains iota and Si-2 (lacking at least one sulfate-activating enzyme), strain eta (lacking PAPS' reductase), strain alpha (blocked somewhere between sulfite and cysteine, probably at O-acetylserine sulfhydrase), and strain "gamma" (lacking sulfate permease and probably PAPS reductase as well). Strain gamma from the same source (Commonwealth Mycological Institute) was reported to be sulfate permease-positive and ATP sulfurylase-negative by Hussey et al. (5) and Spencer et al. (12). It seems quite likely that their strain is not identical with ours. The characteristics of our strain gamma are more like those of mutant strains A and C described by these authors. Similarly, our strain iota lacks ATP-sulfurylase, while they reported iota to be APS-kinase-negative.Growth of Mycelia. Penicillia and Aspergilli mycelia for permease studies were grown for 1 to 2 days on synthetic citrate No. 3 medium (2) containing, as indicated, either 100 mg/liter (low level) or 1 g/liter (high level) of the desired sulfur source. The organisms were grown in submerged liquid culture in 500-ml Erlenmeyer flasks containing 100 ml of medium. The flasks were incubated at 25 C (Penicillia) or 32 to 34 C (Aspergilli) on a rotary shaker operating at about 200 rpm and describing a 1-inch circle. Only white, fine, filamentous ("hairy") mycelia were used for permease studies. The mycelia first produced from a spore inoculum sometimes grew in the form of small pellets. Some strains produced brownish pigmented hairy mycelia or pellets. Such cultures were transferred daily until all pellets and pigmented mycelia were diluted out by the subsequent growth of white, filamentous mycelia.Permease Assay. Sulfate permease activity was usually measured in 0.05 M K+-NH4+-phosphate buffer, pH 6.0, by assay method II as des...
The results of a microbial survey study have shown that the ability to reduce added ketopantoic acid (or ketopantoyl lactone) and accumulate pantoic acid (or pantoyl lactone) in the growth medium is widespread among diverse fungi. The reductions generally proceeded with less than full stereoselectivity. However, specific strains of the ascomycete Byssochlamys fulva were found to form D[-]-pantoic acid in unusually high yields and optical purity.
The rate and extent of stereoselective reduction of 1,3-dioxo-2-methyl-2-(3′-oxo-6′-carbomethoxyhexyl)-cyclopentane to form the 1β-hydroxy-2β-methyl isomer by cultures of Schizosaccharomyces pombe ATCC 2476 was dramatically increased by addition to the fermentation of certain α,β-unsaturated ketones and allyl alcohol.
The results of a microbial survey study have shown that the ability to reduce added ketopantoic acid (or ketopantoyl lactone) and accumulate pantoic acid (or pantoyl lactone) in the growth medium is widespread among diverse fungi. The reductions generally proceeded with less than full stereoselectivity. However, specific strains of the ascomycete Byssochlamys fulva were found to form D[-1-pantoic acid in unusually high yields and optical purity.
Thin-layer chromatography was used to determine the ability of three microorganisms capable of sulfur oxygenation, including Aspergillus niger, Streptomyces armentosus subsp. armentosus, and Calonectria decora, to oxidize 7-methylthioxanthone-2-carboxylic acid to the corresponding sulfoxide in growing cultures. In addition, optical rotary dispersion, circular dichroism, and nuclear magnetic resonance analysis in the presence of chiral shift reagent were used variously to access reaction stereoselectivity, absolute configuration, and optical purity of isolated products. The data indicated that C. decora produced the sulfoxide in high yield (69%) and optical purity (97%), most probably in the S-configuration.
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