摘要:

AbstractThe fungal microflora of a dry valley in southern Victoria Land near McMurdo Sound, Antarctica, was investigated. Samples were collected from introduced objects such as a mummified penguin and spent chewing tobacco in addition to the sparse soil found in rock fissures, isolated moss colonies, shoreline deposit materials, CaCO3precipitates, and microbial mat debris obtained from the frozen surface of the lake in the basin of Taylor Valley. Using conventional media and techniques, all collection sites yielded populations of yeasts and filamentous fungi. Water samples and live microbial mats from beneath the lake ice yielded species of fungi along with an abundance of bacteria.

ISSN:0233-111X    

DOI:10.1002/jobm.3620310102

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

摘要:

AbstractThermostable α‐amylases produced by three different strains ofBacillusspecies are reported. The organisms are isolated from soil. They are designated asBacillus stearothermophilusA004,B. stearothermophilusAN002 andB. coagulansR3.The heat stable amylases produced by these organisms were partially purified and characterized. The temperature optimum forB. stearothermophilusA004 andB. stearothermophilusAN002 amylase is 80 °C, whereas the optimum temperature for amylase activity is 85 °C forB. coagulansR3.The amylases from all three strains show extremely broad pH ranges of activity (6.0–12.0). Furthermore, the α‐amylases fromB. coagulansR3retains 35% activity even at 0.1 n alkali solution. Action of these enzymes on starch produces glucose, maltose, maltotriose, maltotetrose and other higher oligosaccharides, indicating the α‐amylase nature of the t

ISSN:0233-111X    

DOI:10.1002/jobm.3620310103

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

摘要:

AbstractThe enzymes of the leucine pathway ofCandida maltosawere investigated and the regulatory pattern was established. l‐leucine inhibited the α‐isopropylmalate (IPM) synthase, the first enzyme of the pathway. The inhibition was competitive with respect to α‐ketoisovalerate (Ki= 0.81 mm) and non‐competitive with respect to acetyl‐CoA. The Km values of the enzyme were estimated to be 0.57 mm for α‐ketoisovalerate and 0.064 mm for acetyl‐CoA. TheKmvalues of the second enzyme, IPM dehydratase, were estimated to be 4.57, 0.57 and 1.79 for α‐IPM, β‐IPM and citraconate, respectively. TheKmvalues of the β‐IPM dehydrogenase were calculated to be 0.42 mm for β‐IPM and 0.34 mm for NAD+. For this enzyme a novel regulatory pattern, its inhibition by l‐valine, was found. The inhibition was competitive with respect to β‐IPM (Ki= 1.7 mm) and non

ISSN:0233-111X    

DOI:10.1002/jobm.3620310104

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

摘要:

AbstractWhen sectored colonies of a high‐yieldingClaviceps purpureastrain, producing ergotoxine alkaloids in submerged cultures, were investigated significant differences in surface morphology, mycelial differentiation, number of nuclei and in alkaloid production were established among sectors obtained after segregation. Biosynthetically most active sectors showed sclerotia‐like structure and a polynuclear state in cells, while low‐yielding sectors were composed mainly of undifferentiated hyphae with only few nuclei per cell. In cells of high productive sectors the content of DNA was about four times higher than in sectors of lower act

ISSN:0233-111X    

DOI:10.1002/jobm.3620310105

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620310107

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

摘要:

AbstractFrom the mycelia ofAspergillus giganteusmut.albagrown in light and darkness two fractions of glucans were extracted. One of them was purified and characterized by its alkali‐solubility and enzymatic degradation as polymer of β‐d‐g

ISSN:0233-111X    

DOI:10.1002/jobm.3620310108

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

摘要:

Abstract28 yeast strains comprising a number of genera and species have been studied with respect to their ability to use l‐lysine as carbon or nitrogen source. Based on the utilization of this amino acid we could separate the yeasts into 3 groups. Enzymatic investigations demonstrate that yeasts can degrade l‐lysine by two distinct pathways. The first step of both ways was investigated and it was demonstrated that 3 enzymes, acetyl‐CoA: l‐lysine N‐acetyltransferase, l‐lysine α‐aminotransferase, l‐lysine α‐dehydrogenase, are able to catalyze the initial reaction. In 9 yeast strains the acetyltransferase was found. In 21 strains the aminotransferase and in 2 species the dehydrogenase could be detected. The enzyme formation could be enhanced in cells grown in the presence of l‐lysine as sole carbon and/or as

ISSN:0233-111X    

DOI:10.1002/jobm.3620310109

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620310110

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

摘要:

AbstractBy shift experiments after labelling mycelium with d‐glucose‐U‐14C, l‐leucine‐U‐14C or Na15NO3, it was possible to demonstrate that in the biosynthesis of cyclic tetrapeptides during the idiophase,Alternaria alternatauses mycelium compounds produced and stored up in the trophophase. The participation of this protein turnover in the biosynthesis of tentoxin and dihydrotentoxin is very high, and differences are demonstrable concerning the single amino acids. If exogenous amino acids are available the fungus is also able to use them for the formation of the secondary products, in the early idiophase the highest incorporation rate w

ISSN:0233-111X    

DOI:10.1002/jobm.3620310111

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620310112

出版商:Wiley‐VCH    

年代:1991

数据来源: WILEY