摘要:

AbstractA multiple amino acid auxotroph and a wild type ofEscherichia coliK12 were used to study the effects of near minimum growth temperatures on the binding, transport, and cellular incorporation of selected amino acids. Both strains of the bacterium showed the same minimum growth temperature (8°C) when previously grown at 15°C. At 8°C and above, the auxotroph exhibited an overall greater ability to bind and transport amino acids than did the wild type. Below the minimum growth temperature, transport and cellular incorporation including respiration (uptake) were significantly lower for either organism. The NEU and HEPPEL osmotic shock treatment indicated the removal of the specific histidine‐binding protein and the ability to bind histidine was not recovered by further incubation below 8°C. At 8°C and above, the cells recovered their ability to bind histidine within one hour. The evidence presented indicates a direct relationship between the auxotroph's minimum growth temperature and its ability to bind amino acids, specifically meth

ISSN:0044-2208    

DOI:10.1002/jobm.19770170202

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

ISSN:0044-2208    

DOI:10.1002/jobm.19770170203

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractIsolated crystals fromSaccharomyces carlsbergensis, stabilized by Cd2+or Zn2+, retain their enzymatic activity as shown by topochemical reactions. During these reactions the crystals disintegrate characteristically. Stages of this disintegration and deposition of reaction products have been demonstrated by light and electron microscopy. Ground plasmatic and mitochondrial alcoholdehydrogenase has been solubilized by means of 0.01 M EDTA from Zn2+stabilized crystals separated by gel electrophoresis and proved to be active.

ISSN:0044-2208    

DOI:10.1002/jobm.19770170204

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractIt is assumed that the fungistatic effect of terrazol inMucor mucedois induced by a liberation of phospholipases within the mitochondria and perhaps at other membranes. In isolated mitochondria a rapid formation of lysolecithin can be demonstrated at low concentrations of terrazol. This would explain the lytic symptoms in mitochondria visible by electron microscopy. Lipid peroxidation could not be demonstrated. The only antidots at present known for the growth inhibiting effect of terrazol and on its ultrastructural effects are impure saccharose, which seems to contain an unknown factor, and procain hydrochloride or to a lesser extent lidocain, which are well‐known inhibitors of phospholipases. The pathologigal thickening of the cell wall induced by terrazol seems to be an unspecific side effect reflecting a diminished phosphorylating activity of the mitochondri

ISSN:0044-2208    

DOI:10.1002/jobm.19770170205

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractIn connection with the bistability of pyruvate formation in ammonium limited continuous cultures ofE. coliML 30 (BERGTER u. ROTH 1977) the transient behaviour of cell density and pyruvate concentration were studied. Immediately after a shift up in the dilution rate fromD= 0.15 h−1toD= 0.6 h−1the bacteria excreted pyruvate into the medium, followed by a resumption of pyruvate. The specific pyruvate formation rate as well as the specific growth rate reached the new steady state with damped oscillations. Possibly the excretion of pyruvate after the shift is caused by the higher non limiting concentrations of ammonium during the first of the transition. This hypothesis is supported by the transient behaviour of an ammonium limited continuous culture after a pulse of ammonium to the culture. The relations between ammonium metabolism and pyruvate formation are discus

ISSN:0044-2208    

DOI:10.1002/jobm.19770170206

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractA bacterium was isolated from soil which utilizes aniline as sole source of carbon and nitrogen. It was identified asAchromobacter sp. The cells grow at concentrations in the range of 0.5 to 1.25 mg aniline/ml with a growth rate of 0.3 h−1. Substrate inhibition was observed at concentrations higher than 1.5 mg/ml, 3.0 mg/ml completely inhibit the growth. The yield coefficient was 0.63. Aniline was degraded with an activity of 200 μg/mg cell dry weight/hour. Aniline was assimilated and completely degraded. The remaining nitrogen was quantitatively detected as ammonia. The enzyme system involved in aniline degradation was induced by aniline but not repressed by succinate and ammon

ISSN:0044-2208    

DOI:10.1002/jobm.19770170207

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

摘要:

AbstractCarboxylesterase in cell‐free extracts ofStreptomyces hygroscopicuswas characterized with cyclohexylacetate and β‐penta‐acetyl‐D‐glucose as substrates. After concentrating the enzyme, activity withα/β‐methyl‐4‐O‐propionyl‐L‐mycarosid as substrate was also observed. The influence of enzyme effectors was studied. Esterase activity was also found in the culture filt

ISSN:0044-2208    

DOI:10.1002/jobm.19770170208

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

摘要:

Further results on the correlations between the regulation of bacterial cell division and aminoacyl‐tRNA synthetase are presented. Activity of aminoacyl‐tRNA synthetases, extracted from a filamentous mutant ofBacillus subtilisSB 19, may be stimulated by preincubation of crude extracts.The mechanism of this stimulating effect has been studied by means of an inhibitor of aminoacyl‐tRNA synthetases produced during the growth ofAgrostemma githago‐seedlings. According to preliminary results we suggest, this inhibitor can reduce the activity of subunits only, but not that of higher associates. Association of subunits to oligomers will be prevented by the inhibitor, too. Our results may be indicative of the assumption that the increase of enzyme activity during preincubation of bacterial extracts, eliminated by the inhibitor, is changed by the association of subunits with a low catalytic activity to functional oligomers.As to the verification of these hypotheses further work will still have to

ISSN:0044-2208    

DOI:10.1002/jobm.19770170209

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

ISSN:0044-2208    

DOI:10.1002/jobm.19770170210

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY

ISSN:0044-2208    

DOI:10.1002/jobm.19770170213

出版商:Akademie‐Verlag    

年代:1977

数据来源: WILEY