摘要:

AbstractThebg/M gene DNA coding for a thermostable beta‐1.3,1.4‐glucanase ofBacillus maceransE138 was isolated by direct shot‐gun cloning intoEscherichia coliusing plasmid pBR322 as a vector. By deletion analysis thebg/M coding region was located within a 1.0 kb region of the clonedBacillusDNA fragment. InE. coli, plasmid pBGLM12/2 containing theB. macerans bg/M gene gave rise to a beta‐glucanase expression 40 times higher than that of theB. maceransgene donor. The molecular weight of beta‐glucanase, isolated either fromE. colicells or from the culture filtrate ofB. macerans, was in the range of 24 kD. The enzymes purified fromE. colior from the culture filtrate ofB. macerans, had a halflife of about 40 min at 65 °C. This indicated an increased temperature stability of theB. maceransenzyme in comparison to otherBacillus‐bet

ISSN:0233-111X    

DOI:10.1002/jobm.3620280102

出版商:Wiley‐VCH    

年代:1988

数据来源: WILEY

摘要:

AbstractThe anticancer drug netropsin increases the synthesis of an exocellular metalloproteinase during exponential growth as well as in the stationary phase of a sporulating strain ofBacillus megaterium. Its effect is due to a stimulation of the synthesis of the mRNA coding for the proteinase, determined as a residual synthesis of the enzyme in the presence of actinomycin D. The half‐life of the proteinase mRNA (5–6 min at 35 °C) is not affected by netropsin. Netropsin relieves partially the repression of the proteinase mRNA caused by amino acids, whereas the repression brought about by an increased temperature is almost unaffected by the

ISSN:0233-111X    

DOI:10.1002/jobm.3620280103

出版商:Wiley‐VCH    

年代:1988

数据来源: WILEY

摘要:

AbstractThe enzymatic interconversion of the aclacinomycins A (I), Y (II), and B (III) byStreptomycesspec. AM 33352/S 182 producing these aklavinone glycosides was investigated. The enzymes converting I to II and III, as well asvice versa, are located within different compartments separated by the cytoplasmic membrane.

ISSN:0233-111X    

DOI:10.1002/jobm.3620280104

出版商:Wiley‐VCH    

年代:1988

数据来源: WILEY

摘要:

AbstractNADP+‐dependent aldehyde dehydrogenase from the cytosolic fraction of the alkane‐degradating ‘Acetobacter rancens’ CCM 1774 was purified 112‐fold (specific activity of 112 nkat mg−1protein). After polyacrylamide gel electrophoresis of the purified enzyme only one band was visible. The relative molecular weight was estimated to be 82,000 by both gel filtration and disc gel electrophoresis. The substrate specifity of the purified enzyme within the straight chain aliphatic aldehyde series is confined to acetaldehyde and propionaldehyde. Butyraldehyde and formaldehyde are considerably less converted. NADP+alone served as electron acceptor. Mg2+stimulated the reaction velocity in a strong manner by ‘non‐competitive’ activation. The estimation of kinetic parameters and inhibition experiments of the irreversible oxidation of ethanal indicate a random kinetic mechanism at optimal aldehyde concentrations and saturating NADP+concentrations at optimal pH 8.5 which, however, trends to become ordered with decreasing pH values. Properties described exclude the participation of the enzyme in degradation ofn‐alkanes. One physiological function of this constitutive aldehyde dehydrogenase may be the intracellular detoxification of short chain aldehydes by conversion to corres

ISSN:0233-111X    

DOI:10.1002/jobm.3620280105

出版商:Wiley‐VCH    

年代:1988

数据来源: WILEY

摘要:

AbstractStarting with germinating spores ofStreptomyces granaticolor, the kinetics of elongation of 3 types of outgrowing hyphae was determined. The 3 hyphal types were: first germ tube, second germ tube (which appeared from the same spores about 3 hours later) and branches arising from the first germ tubes. Taking photographs every fifth minute, with all hyphae a linear multiphasic elongation behaviour was found. Alternatively, periods with constant elongation rate (α) changed with steps at which α increased abruptly. Several successive shifts were observed until finally at a hyphal length of about 25 μm a constant maximum α of about 22 μm h−1was attained.The length of the periods during which α remained constant did not depend on either the hyphal type or the order of the period. On an average, a single period lasted 46.8 minutes.The lengths of the hyphae, at the time when α increased, corresponded for the first germ tubes to successively about 2,4,8 and 16 unit cells. With branches and second germ tubes these lengths corresponded to 4 and 10 unit cells.Concerning increase of α during each step the quotients were in the range between 1.3 and 2.0. Branches and second germ tubes started with twice the rate observed with first germ tubes and thus reached the maximum α after a reduced number of steps. Calculations indicated, that on principle α of each linear period was determined by the number of unit cells (nucleoids) present at it

ISSN:0233-111X    

DOI:10.1002/jobm.3620280106

出版商:Wiley‐VCH    

年代:1988

数据来源: WILEY

摘要:

AbstractA method is presented allowing a clear distinction between bacterial viruses T3 and T7 by plating on selectively permissive host cells. The indicator strains areEscherichia colicells containing either clonedpifgenes (exclusively permissive for T3) or theEcoRV DNA restriction system (permissive only for T7): The efficiencies of plating of the two phages on these hosts differ by more than 8 orders of magnitude. This method was applied to reinvestigate the controversial question of mutual exclusion between T3 and T7. Under single‐burst conditions, about 50% of coinfected cells (permissive for both viruses) produced T3andT7 progeny while about 25% reproduced only T3 and about 25% only T7. The burst size of co‐infected cells was slightly reduced, compared to controls infected with only one virus type. Homologous exclusion among T3 phages was also not seen; rather, there was a gene dosage effect: T3‐encoded RNA polymerase activity as well as T3‐specific RNA synthesis increased proportionally to the multiplicity of infection (2.5–20 plaque‐forming

ISSN:0233-111X    

DOI:10.1002/jobm.3620280107

出版商:Wiley‐VCH    

年代:1988

数据来源: WILEY

摘要:

AbstractThe human gene for mature interferon‐α1 (IFN‐α1) was inserted in a new transcription‐translation fusion vector system based on the expression and secretion signals of the gene for typeAstreptococcal pyrogenic exotoxin,speA. As deduced from the known nucleotide sequences of the component elements, the encoded IFN‐α1 was a fusion protein carrying an N‐terminal extension of 17 amino acids. When inserted in appropriate vectors capable of replication inEscherichia coli, Bacillus subtilisandStreptococcus sanguis, this expression configuration directed the synthesis of antiviral activity in all 3 organisms, as judged by the cythopathic effect inhibition assay of Vesicular Stomatitis Virus. InE. coliJM101, IFN activity was found mainly in the cytoplasmic protein fraction whereas in the gram‐positive hosts, it was completely secreted into the

ISSN:0233-111X    

DOI:10.1002/jobm.3620280108

出版商:Wiley‐VCH    

年代:1988

数据来源: WILEY

摘要:

AbstractBesides tentoxin, dihydrotentoxin is produced byAlternaria alternatain similar quantities. Both peptides are excreted mainly into the culture medium, with a low content (20–55 μg/g) being found in the mycelium already of an early stage of fermentation. Tentoxin is not degraded during cultivation, therefore, dihydrotentoxin cannot be a decomposition product of the phytotoxin. During the isolation procedure, some tentoxin (10 to 15%) and even more dihydrotentoxin (30–40%) is lost. Incorporation of labelled dihydrotentoxin (14C,15N) into tentoxin during fermentation allows the conclusion that the nonoxidized peptide is the precusor of tent

ISSN:0233-111X    

DOI:10.1002/jobm.3620280109

出版商:Wiley‐VCH    

年代:1988

数据来源: WILEY

摘要:

AbstractHitherto, lower growth yields were found with acidophilic methylotrophic bacteria, than those found with neutrophilic methylotrophic ones. Since differences with respect to the oxidative phosphorylation might be responsible for this phenomenon, P/0 quotients were determined for the oxidation byAcetobacter methanolicussp. MB 70 of endogenous substrates, methanol and other substrates. P/0 quotients for endogenous substrates were calculated from the formation of “energy‐rich” phosphate bonds and the concomitant oxygen uptake on transition of the cells from anaerobiosis to aerobiosis in the range between 0.07 to 0.17 nmol P/nmol 0. P/0 quotients for methanol between 0.1 to 0.25 were determined under aerobic conditions by intracellular energization. For this purpose, the energy charge was decreased to values lower than 0.5 by changing the extracellular pH from 4.0 to 7.0, and increased again to values from 0.7 to nearly 1.0, by adding methanol. The addition of FCCP and DCCD2) totally prevented the increase of the ATP concentration. The energization of the same cell preparation produced similar P/0 quotients for methanol, ethanol and glucose. But in a certain cell preparation, the P/0 quotient for glucose (0.01) was considerably lower than that for methanol (0.18); this was the only quotient reduced from 0.12 to 0.05 by aerating the former cell preparation for 4 h. The results are discussed in terms of the coupling of dehydrogenase reactions, for endogenous and exogenous substrates, to the cytochromes of the respiratory chain. Its composition and structure before cytochrome c appears to be responsible for the fact that the growth yields of these bacteria are smaller than expected for such a type of methylot

ISSN:0233-111X    

DOI:10.1002/jobm.3620280110

出版商:Wiley‐VCH    

年代:1988

数据来源: WILEY

摘要:

AbstractThe conversions of agroclavine to elymoclavine and elymoclavine to paspalic acid/lysergic acid are catalyzed by microsomal preparations from variousClavicepsstrains. The enzymes designated as agroclavine 17‐monooxygenase and elymoclavine 17‐monooxygenase respectively are dependent on NADPH and molecular oxygen. NADH enhances enzyme activity observed in the presence of NADPH. Transhydrogenase activity in the presence of NADH and NADP+which is dependent on ATP was found. Carbon monoxide, as it was shown by KIMet al.(1981, 1983) and cytochrome c inhibit hydroxylation, whereas NACN did not affect the reactions. This and other properties suggest that both clavine specific enzymes are cytochrome P‐450 dependent monooxygenases. Lysergol was not converted by elymoclavine 17‐hydroxylase. Feedback inhibition of agroclavine 17‐monooxygenase by elymoclavine was demonstrated underin vitroc

ISSN:0233-111X    

DOI:10.1002/jobm.3620280111

出版商:Wiley‐VCH    

年代:1988

数据来源: WILEY