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991.
Eight strains of bacteria utilizing tetralin as sole source of carbon and energy have been obtained. Four strains have been selected from culture collections. The others were isolated from hydrocarbon-polluted areas. The newly isolated strains belong to the genera Acinetobacter, Arthrobacter and Moraxella. Most of the selected strains were able to grow on other aromatic hydrocarbons, but none of them grew on cyclohexane. Tetralin-utilizing organisms were difficult to isolate and cultivate, because tetralin was toxic to the cells at concentrations above 15 l/l. Consequently tetralin was supplied either via the vapour phase or an organic solvent/water two-phase system was employed.Abbreviations FC 40
fluorocompound 40
- DBP
dibutylphthalate
- DEP
diethylphthalate
- DOP
dioctylphthalate 相似文献
992.
H. Berndt K. -P. Ostwal J. Lalucat Christa Schumann F. Mayer H. G. Schlegel 《Archives of microbiology》1976,108(1):17-26
The coryneform hydrogen bacterium strain GZ 29, assigned to Corynebacterium autotrophicum fixed molecular nitrogen under autotrophic (H2, CO2) as well as under heterotrophic (sucrose) conditions. Physiological parameters of nitrogen fixation were measured under heterotrophic conditions. The optimal dissolved oxygen concentration for cells grown in a fermenter with N2 was rather low (0.14 mg O2/l) compared with cells grown in the presence of NH
4
+
(4.45 mg O2/l). C. autotrophicum GZ 29 had a doubling time of 3.7 h at 30°C with N2 as N-source and sucrose as carbon source and at optimal pO2. Acetylene reduction reached values of 12 nmoles of ethylene produced/minxmg protein. Although the oxygen concentration in the growing culture was kept constant, the optimal dissolved oxygen tension for the acetylene reduction assay shifted to higher pO2-values. The overall efficiency of nitrogen fixation amounted to 22 mg N fixed/g sucrose consumed; it reached a maximal value of 65 mg N fixed/g sucrose consumed at the beginning of the exponential growth phase. Intact cells reduced acetylene even under anaerobic test conditions; further anaerobic metabolic activity could not be ascertained so far. 相似文献
993.
Isolated beef heart cytochromec oxidase was reconstituted in liposomes by the cholate dialysis method with 85% of the binding site for cytochromec oriented to the outside. Trypsin cleaved specifically subunit VIa and half of subunit IV from the reconstituted enzyme. The kinetic properties of the reconstituted enzyme were changed by trypsin treatment if measured by the spectrophotometric assay but not by the polarographic assay. It is concluded that subunit VIa and/or subunit IV participate in the electron transport activity of cytochromec oxidase. 相似文献
994.
Gábor L. Lövei Éva Monostori istván Andó 《Entomologia Experimentalis et Applicata》1985,37(2):123-127
Prey antigen levels were determined by a quantitative enzyme-linked immunosorbent assay in larvae of a carabid predator, Poecilus cupreus L. under laboratory conditions. We determined prey consumption and rate of prey protein decay in larvae having starved for different periods. Prey consumption increased exponentially over 7 days of starvation. The rate of prey immunoreactive material decay seemed to be logarithmic, similar in larvae which had starved for different periods. Most of the digestion took place in the first 3 days period after feeding, irrespective of the amounts ingested. The rate of decay increased with increasing period of starvation. There were also signs of food retention in the alimentary canal in larvae which starved longer.
Zusammenfassung Mit eine quantitativen enzymabhängigen Immunoabsorptionstest wurde immunoreaktives Material aus Beutetieren als Eiweissgehalt (IRM/P) in Larven eines polyphagen räuberischen Carabiden, Poecilus cupreus, bestimmt. Wir bestimmten den Beuteverzehr und die Geschwindigkeit des IRM/P Abbaus bei Larven, die während verschiedener Zeit gehungert hatten. Der Beuteverzehr nahm exponentiell zu über 7 Tage Hunger. Die Geschwindigkeit des Beute- IRM/P Abbaus schien logarithmisch. Die Beuteaufnahme nahm fast zwanzigfach zu über 7 Tage Hunger von 2.7 ng auf 50.2 ng IRM/P/10 Mikroliter Larvenextrakt. Der grösste Teil der Verdauung erfolgte am zweiten bis dritten Tag nach der Nahrungsaufnahme, unabhängig von der verdauten Menge. Das Niveau 4 Tage nach der Fütterung zeigte, dass Larven, die vorgängig 7 Tage gehungert hatten, 5.0 ng IRM/P/10 Microliter Extrakt zurückhielten; dies war mehr als die Aufnahmemenge nichthungernder Larven. Die Verdauungsgeschwindigleit nahm zu mit der Dauer des Hungerns, doch wurde auch mehr Beute im Nahrungskanal zurückgehalten.相似文献
995.
996.
Spontaneous mutants of Methanobacterium strain FR-2 resistant to bacitracin were isolated at a frequency of approximately 10-7 and showed minimum inhibitory concentrations 8 to 16-fold that of the wild type organism. The mutant strains reverted to sensitivity during culture in the absence of bacitracin. Repeated transfer in medium containing 8 g bacitracin/ml resulted in the selection of a stable resistant strain with a specific growth rate, in the absence of bacitracin, comparable to that of the wild type. Resistance to bacitracin conferred cross-resistance to nisin.Abbreviations MIC
minimum inhibitory concentration
- EDTA
ethylenediaminetetraacetic acid 相似文献
997.
The process of digestion was studied in some polar pycnogonids, mainly the Antarctic forms Nymphon australe and Nymphon orcadense. Our findings did not support the theory of the digestive process proposed by Schlottke (1933) and this led to a re-examination of his ideas. We propose a new scheme for digestion in pycnogonids and fit Schlottke's observations into this framework. It is suggested that Antarctic pycnogonids may possess behavioural adaptations peculiar to their supply of food. Some directions for further study are indicated. 相似文献
998.
DNA molecules were adsorbed to a polylysine-treated carbon film and digested directly on the film by restriction enzymes. After washing the film with 1 M NaCl, 0.4% Kodak Photo-Flo and 9% formamide, each cleavage site introduced was visualized as a gap under the electron microscope. By measuring the gapped positions on linear DNA molecules induced by other enzymes, a single EcoRI site on a lambda dv1 molecule and three HinHI sites on an fd1RF molecule were mapped at the positions expected from the cleavage maps, respectively. This electron-microscopic procedure may be useful for the construction of a cleavage map. 相似文献
999.
A specific structural association between spectrin component 1 and band 3 in human erythrocyte membrane has been demonstrated by covalent cross-linkings, specific labeling, and the technique of two-dimensional gel electrophoresis. A complex of 330,000 daltons, representing 1 + 3, was produced in mildly oxidized membranes at physiologic pH and isotonic conditions but not at hypotonic conditions (< 10 mM KCl or NaCl). The yield of this complex decreased dramatically as the monovalent cation concentration decreased from 90 mM to 30 mM. The presence of Mg++ or Ca++ (2 mM) at low ionic strength promoted 1 + 3 cross-linking in an amount similar to that produced at isotonic conditions. The specific segment of band 3 involved in the cross-linking was also investigated by means of chymotrypsin digestion of band 3 in the intact red cells. The results showed the cross-links between spectrin component 1 and the 55,000-dalton fragment of band 3 at physiologic pH and isotonic conditions. This is consistent with the idea that band 3 is anchored on or contacted with the submembrane meshwork at the cytoplasmic membrane surface. 相似文献
1000.
The structure of rabbit, fowl, and Xenopus laevis sperm chromatin was explored by study of the reaction of their decondensed nuclei with DNase 1 and micrococcal nuclease. Those of rabbit and fowl were readily digested by DNase 1, and the polyacrylamide gel electrophoresis profiles of DNAs extracted from the digests were similar, each being polydisperse with a single discrete band of DNA smaller than 72 base pairs. There were differences, however, between the sperm chromatins in the course of their digestion by micrococcal nuclease. A limit digest at about 45% acid solubility was obtained with Xenopus sperm chromatin, while 90% of fowl sperm DNA was rendered acidsoluble by the enzyme. The gel profiles of the limit digests were polydisperse, but only those of rabbit and fowl sperm chromatins possessed a discrete band of DNA smaller than 72 base pairs. Bleomycin did not react with DNA of rabbit, fowl, or Xenopus spermatozoa. Since bleomycin reacts with somatic cell chromatin, and the course of DNase 1 or micrococcal nuclease digestion of sperm chromatin was different from that found for somatic cell chromatin, it would appear that sperm chromatin does not have the repeating nucleosometype structure of somatic cell chromatin. The nuclease digestion studies further suggest that the organization of rabbit and fowl sperm chromatins is similar, and is different from that of Xenopus sperm chromatin. The dependence of the structure of sperm chromatin on the composition of its basic proteins, and a possible structure for a protamine-type sperm chromatin, are discussed. 相似文献