摘要:

AbstractThe DNA‐dependent RNA polymerases from heat‐shocked and vegetatively grown cells ofBacillus subtiliswere isolated and compared. The RNA polymerase from non‐stressed cells had the well knowna, ß, ß' and σ composition of eubacterial RNA polymerases. The RNA polymerase from heat‐shocked cells exhibited one additional band shown by SDS‐PAGE. N‐terminal sequencing of the first 16 amino acids of the associated protein demonstrated its identity with the riboso

ISSN:0233-111X    

DOI:10.1002/jobm.3620370102

出版商:Wiley‐VCH    

年代:1997

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620370103

出版商:Wiley‐VCH    

年代:1997

数据来源: WILEY

摘要:

AbstractElectrophoretic analysis of the proteins bound to poly(3‐hydroxybutyric acid), PHB‐, granules inMethylobacterium extorquens, M. rhodesianumas well as the PHB‐leaky mutants Mu 1 and Mu 11, which were isolated from the latter, resulted in two dominant low‐molecular weight proteins, which were referred to as GA 11 and GA20. After purification of these proteins antibodies against the GA11 and GA20 protein ofM. extorquenswere obtained. Both proteins bound to the surface of PHB granules as revealed by immunoelectron microscopy of whole cells ofM. extorquensandM. rhodesianum. With cells of the PHB‐leaky mutants Mu 1 and Mu 11 no specific labeling was observed. The N‐terminal amino acid sequences of the GA11 and the GA20 protein were determined. We found significant homologies between the sequences of the investigated strains. The use of oligonucleotide probes based on the N‐terminal sequences of the GA20 protein fromM. rhodesianumto identify the corresponding structural genes in various genomic lib

ISSN:0233-111X    

DOI:10.1002/jobm.3620370104

出版商:Wiley‐VCH    

年代:1997

数据来源: WILEY

摘要:

AbstractTranscriptional activation studies involving the human oncoprotein and transcription factor Myc and its helix‐loop‐helix partner protein Max in mammalian cells are critical due to the presence of endogenous Myc and Max proteins. Here we show that co‐expression of the human c‐mycandmaxgenes from 2μ circle derived high copy number vectors in yeast cells stimulate the transcriptional activation of aLacZreporter gene fused to the yeast cytochrome‐c1, oxidase minimal promoter containing the adenovirus major late promoter element (AMLPE). The exchange of the single Myc binding site in the AMLPE by the two E‐box DNA motifs (CACGTG) present in the Myc responsive element of a human Myc target gene (ornithine decarboxylase) in front of a promoter‐reporter gene cassette results in a two‐fold enhanced ß‐galactosidase expression. Low expression ofmaxand high level expression of c‐mycat the same time led to a further enhancement of transcriptional activation from this promoter

ISSN:0233-111X    

DOI:10.1002/jobm.3620370105

出版商:Wiley‐VCH    

年代:1997

数据来源: WILEY

摘要:

AbstractThe regulation pattern of L‐lysine biosynthesis has been investigated in protrophic revertant derived from an initially homoserine‐auxotrophic strain ofCorynebacterium glutamicumand, additionally, in antimetabolite‐resitant mutants. The influence of regulatory important amino acids of the aspartate family on growth and L‐lysine biosynthesis and especially on the activity of aspartate kinase was studied. Furthermore the activity of homoserine dehydrogenase in dependence on the growth phase was estimated.From a total number of ninety nine L‐lysine forming, homoserine‐prototrophic, and S‐(2‐aminoethyl)‐L‐cysteine‐resistant (AEC) strains the best lysine producers were selected by an emerse cultivation assay as a preselection. Strain No. 132 forming 10 g · 1−1lysine was selected for the derivation of α‐amino‐β‐hydroxyvaleric acid (AHV)‐ and lysine‐resistant strains. From 121 double resistant mutants (hse−rev, AECr, AHVr) sixty two strains (=51.2%) were isolated producing lysine. The best producer, strain 132‐IV‐37, reached 19.8 g · 1−1after 8 optimization steps of the growth medium in comparison to 9.2 g · 1−1as the initial value. This higher potential for lysine synthesis in the mutant 132‐IV‐37 could be attributed to changed regulation of the homoserine dehydrogenase and aspartate kinase.As was shown by the action of threonine or threonine + lysine on the activity of aspartate kinase, a general desensibilization of this key enzyme exists in the mutant strain 132‐IV‐37, but not in the AEC‐resistant parent strain. In addition to isoleucine none of several amino acids tested showed any significant influence on the aspartate kinase. This agrees with the increased lysine forma

ISSN:0233-111X    

DOI:10.1002/jobm.3620370106

出版商:Wiley‐VCH    

年代:1997

数据来源: WILEY

摘要:

AbstractThe antibacterial effect of 19 new commercially manufactured disinfectant substances on aSalmonella typhimuriumstrain was studied. The substances tested represent 9 quaternary ammonium salts (QAT) and 11 combinated QAT with other ingredients. The antimicrobial efficacy was characterized by influencing the growth and reproduction of bacterial cells expressed either by MIC and ED50values (ED50 values represent concentration of substance in μ/ml which cause inhibition of growth by 50%), as well as by the inhibition of incorporation rate of [14C] adenine and [14C] leucine. The disinfectants are divided into three groups according to their efficacy. The first group comprises substances with strong inhibitory effect (MIC 0.04–0.19 μ/ml) such as Neoquat S, Antibacteric P, Divoquat forte, Sokrena and Diesin forte (sole from the group belonging to multicomponent substances). QAT except Antibacteric P interfere with energy metabolism (R values ∼1). The second group represents substances with good antibacterial efficacy (MIC values up 1.56 μg/ml), and the third group substances with MIC values up 12.5 μg/ml. Cutasept G was found ineffective also in the concentration 100 μg/ml. The method of inhibition of [14C] precursors is suitable as one from possible criterion in evaluation of antibacterial efficacy of various synthetic su

ISSN:0233-111X    

DOI:10.1002/jobm.3620370107

出版商:Wiley‐VCH    

年代:1997

数据来源: WILEY

摘要:

AbstractThe thickness of the boundary layer surrounding polyhydroxyalkanoic acid (PHA) inclusion bodies in bacteria was determined from electron micrographs of ultrathin cell sections. The obtained values were compared with the thickness of boundary layers of other kinds of prokaryotic inclusion bodies known to be monolayers (sulfur globule, hydrocarbon‐containing inclusion, carboxysome, gas vesicle, chiorobium vesicle) and the thickness of typical bilayer membranes (cytoplasmic membrane, photosynthetic vesicle). The data are discussed in view of contradicting models published recently for the molecular architecture of the boundary layer of PHA inclusion bodie

ISSN:0233-111X    

DOI:10.1002/jobm.3620370108

出版商:Wiley‐VCH    

年代:1997

数据来源: WILEY

摘要:

AbstractThe intracellular level of DNA supercoiling is regulated inEscherichia coliby a homeostatic control mechanism that includes DNA gyrase and topoisomerase I gene expression. Despite several biochemical and genetical evidence that supports the existence of a homeostatic regulation mechanism, there are only few studies focusinggyrA andgyrBgene expression in connection to the mechanism involved in the regulation of DNA supercoilingin vivo. To study DNA gyrase gene expression and to be able to isolate mutants with altered expression of DNA gyrase, we constructed a new chromosomal reporter system based on two translational fusions ofgyrA andgyrBtolacZ. Using this stable monitor system in a robust wild type, we simultaneously studied the influence of several inhibitors of DNA gyrase (quinolones and coumarins) ongyrA andgyrBgene expression as well as on the intracellular level of DNA supercoiling. Surprisingly, we found a delayed and differential response ofgyrA andgyrBgene expression following inhibition of DNA gyrase by quinolones or coumarins. Whereas both groups of drugs were able to increase the expression ofgyrA, thegyrBgene expression was only induced by the coumarins. Although the action of the quinolones was able to alter DNA supercoiling, we never observed any induction ofgyrBfrom the chromosome. These results revealed that the gene expression ofgyrA appears to be more sensitive to alterations in DNA supercoiling than thegyrBgene expression and suggest that probably additional regulatory mechanisms on the post‐translational level might be involved in the regulation of DNA supercoiling and DNA gyrase gene expressio

ISSN:0233-111X    

DOI:10.1002/jobm.3620370109

出版商:Wiley‐VCH    

年代:1997

数据来源: WILEY

摘要:

AbstractThreeBacillus thuringiensisflagellar (H) serogroups were newly detected in the populations associated with sericultural and natural environments of Japan. A total of 44B. thuringiensisstrains, derived from seven prefectures in Honshu, Shikoku, and Kyushu, were assigned to the H serotypes 34 (serovarkonkukian), 35 (serovarseoulensis), and 43 (serovarguiyangiensis). Of the 44 strains, three of the serovarkonkukianand one strain of the serovar guiyangiensis exhibited moderate larvicidal activity specific for the mosquito,Aedes aegypti. None of the strains showed toxicity against larvae of the silkworm,Bombyx mori.

ISSN:0233-111X    

DOI:10.1002/jobm.3620370110

出版商:Wiley‐VCH    

年代:1997

数据来源: WILEY

ISSN:0233-111X    

DOI:10.1002/jobm.3620370101

出版商:Wiley‐VCH    

年代:1997

数据来源: WILEY