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41.
A bacitracin-producing strainBacillus licheniformis ATCC 10716 harbors two types of inducible phages (LP52 and DLP 10716). 156 strains re-lysogenized with phage LP52 were independently isolated from a cured strain UM12 ofB. licheniformis. Those strains were divided into 12 groups based on colony morphology and pigment production. Some of the re-lysogenized strains grew faster than UM12 and others produced more bacitracin than the cured strain. For example, the production of bacitracin by one of the relysogenized strains, L89, was enhanced by about 70% in comparison with UM12. The phenotypic variations observed with re-lysogenized strains might be due to the re-insertion of the phage genome at different sites of the chromosome in addition to the pleiotropic effect assumed.Abbreviations ATCC
American Type Culture Collection
- DNA
Deoxyribonucleic acid
- MC
Mitomycin C
- OD
Optical density
- PFU
Plaque forming unit
- rpm
Revolutions per minute
- UOD
Unit of optical density
- UV
Ultraviolet
Definition
Specific growth rate (h-1)
-
t
time (h)
-
X
cell concentration (g/l) 相似文献
42.
43.
The activity of a neutral protease is increased in soluble fractions from the intestine of rats after a shift from a protein-free to a casein mash and an injection of triiodothyronine. The increased activity is prevented by the administration of cycloheximide. The time curve of the response of the protease activity in intestine is similar to that of liver DNA synthesis after a shift to 50% casein and triiodothyronine. 相似文献
44.
The in vitro culture of isolated microspores of two cultivarsof Paeonia, P. lactiflora cv. "Kumoinotsuru" (2n=10) and cv."Toyonoakari" (2n = 10), was attempted. With both cultivars,some cultured microspores (36%) began to divide afterfive to seven days of culture. Those of "Kumoinotsuru" grewinto calli, whereas the others degenerated. Cytological examinationof the callus developed from a microspore revealed haploids,diploids or a mixture of both. No direct embryo formation frommicrospores was observed in this experiment. (Received December 1, 1980; Accepted January 16, 1981) 相似文献
45.
Abstract: Methylazoxymethanol (MAM) injection to rats on day 15 of gestation caused a significant rise in monoamine concentrations (1.6, 2.0, and 2.8 times the control value for serotonin, norepinephrine, and dopamine, respectively) accompanying a decrease in the brain weight and DNA content in the cerebral hemispheres of the offspring at 3 months of age; in the brain stem, these changes were much smaller. Similar change of monoamine concentrations was observed in cytosine arabinoside-induced microencephaly. The decrease of DNA content and the elevation of monoamine levels were lower with MAM injection on day 15, 13, or 17 of gestation (in that order). Serotonin content of the MAM-treated cerebral hemispheres was already 50% higher than the control immediately after birth. The activity of tryptophan hydroxylase in the MAM-treated cerebrum was 1.6 times the control value, with no change in the brain stem, while the concentration of tryptophan in the brain and plasma was equal to the control value, suggesting an important role played by this enzyme in the elevation of serotonin content. Although the marked decrease of DNA content in the cerebral hemispheres of MAM-treated rats indicates a loss of cerebral cells due to prenatal MAM poisoning, the kind of cells destroyed remain to be studied. That the remaining neurons, axons, and oligodendroglia were intact was suggested by the normal activity of CNPase. 相似文献
46.
Katsuhiko Mikoshiba Shinichi Kohsaka Ken Takamatsu Emiko Aoki Yasuzo Tsukada 《Journal of neurochemistry》1980,34(4):835-844
Abstract: Cerebral cortex from reeler mutant mice was examined morphologically and biochemically. The sequential process of postnatal cell migration in the cerebral cortex of reeler (rl/rl) was examined morphologically. The dense cellular cortical plate lies below the molecular layer near the cerebral surface just after birth in normal mice while in reeler most of the cells are concentrated in the center of the cortex. In the cortex of adult reeler, the broad laminar structure of the neurons could be seen to form inverted positions in the cortical layers. The total wet weight, and the concentration of DNA and RNA in the pallium cerebri from reeler did not differ significantly from those in the control. As to the protein profiles of the pallium cerebri detected by SDS- polyacrylamide gel electrophoresis, no significant differences were observed. Activities of CNPase (2',3'-cyclic nucleotide 3'-phosphohydrolase), which is a myelin enzyme of CNS, and choline acetyltransferase were at the same level in both the reeler and the control. Therefore, reeler mutation does not appear to affect the genetically determined cell numbers, number of cholinergic fibers, and myelination. By autoradiographic observation of the cerebral cortex after intraperitoneal injection of [14 C]2-deoxyglucose, it was revealed that 2-deoxyglucose was incorporated intensively into the fourth layer (granular layer) of the cerebrum from the control. In reeler it was also incorporated into the granular layer but in a more widespread distribution. We conclude that terminals to the granular layer make metabolically active synapse, perhaps even in a manner inverted from normal. 相似文献
47.
Adenosine deaminase (EC 3.5.4.4) was found to occur in the extract of Azotobacter vinelandii, strain 0, and purified by heating at 65°C, fractionation with ammonium sulfate, DEAE-cellulose chromatography and gel filtration on Sephadex G-150. Purified adenosine deaminase was effectively stabilized by the addition of ethylene glycol. The molecular weight of the enzyme was estimated to be 66,000 by gel filtration on Sephadex G-150. The enzyme specifically attacked adenosine and 2-deoxyadenosine to the same extent, and formycin A to a lesser extent. The pH optimum of the enzyme was observed at pH 7.2. Double reciprocal plot of initial velocity versus adenosine concentration was concave upward, and Hill interaction coefficient was calculated to be 1.5, suggesting the allosteric binding of the substrate. ATP inhibited adenosine deaminase in an allosteric manner, whereas other nucleotides were without effect. The physiological significance of the enzyme was discussed in relation to salvage pathway of purine nucleotides. 相似文献
48.
DNA kinase has been purified to homogeneity from calf thymus. The purified enzyme, with a specific activity of 16.7 units/mg protein at 25 degrees C, exhibited a sharp pH/activity curve with a pH optimum at 5.5 and low activity at alkaline pH. The molecular weight of the enzyme was estimated by dodecylsulfate/polyacrylamide gel electrophoresis to be 5.4 X 10(4). The enzyme has a sedimentation coefficient of 4.0 S. An apparent molecular weight of 5.6 X 10(4) and a Stokes' radius of 3.3 nm were estimated by gel-filtration on Sephadex G-100. The enzyme phosphorylates neither yeast RNA nor poly(A) instead of DNA. Compared with rat liver DNA kinase, calf thymus DNA kinase is relatively resistant to the inhibition by sulfate (Ki = 7 mM) and pyrophosphate (Ki = 5 mM). The enzyme activity is markedly stimulated by polyamines at the sub-optimal concentration of Mg2+ but not by monovalent cations. 相似文献
49.
Masuo Aizawa Mitsuo Wada Seishi Kato Shuichi Suzuki 《Biotechnology and bioengineering》1980,22(9):1769-1783
Nonphosphorylating electron transport particles (ETP) prepared from beef heart mitochondrion were immobilized in agar gel. The immobilized ETP showed an oxidase activity to both NADH and succinate. The immobilized ETP was reusable. An electrochemical device for the determination of either NADH or succinate was assembled consisting of the membrane-bound ETP and an oxygen probe. The response to succinate was specifically inhibited by the addition of malonate. 相似文献
50.
The concept of mass balance was used to analyze the metabolic pathways of citrate production by Candida lipolytica from glucose. Specific rates of glucose consumption, citrate and isocitrate productions, carbon dioxide evolution, and cellular syntheses of protein and carbohydrate were observed in an NH4+-limited chemostat culture. These data permitted one to assess the carbon flux in vivo by solving simultaneous carbon balance equations with respect to intermediary metabolite pools in the steady State. Among the three models considered here, model I (which coordinates the pyruvate carboxylation with the tricarboxylic acid cycle, but disregards the glyoxylate cycle) was considered plausible because the carbon flux calculated so far was acceptable. On the other hand, models II and III (which overlook the pyruvate carboxylation and the 2-oxoglutarate dehydrogenation, respectively) were found to be most unlikely because of the unusual flux assessed from these models. 相似文献