共查询到20条相似文献,搜索用时 15 毫秒
1.
Fine structure of the recB and recC gene region of Escherichia coli 总被引:14,自引:0,他引:14
M Sasaki T Fujiyoshi K Shimada Y Takagi 《Biochemical and biophysical research communications》1982,109(2):414-422
2.
C H Letendre P C MacDonnell G Guroff 《Biochemical and biophysical research communications》1976,76(2):615-617
Determination of the complete amino acid sequence of the rubredoxin isolated from the sulfate reducing bacterium showed that the molecule consists of a single polypeptide chain of 52 residues. The sequence of the first 42 residues was determined using an automatic Protein Sequencer. Peptides derived from tryptic hydrolysis and from specific cleavage at tryptophan residue were used to construct the total sequence. Compared with the sequence of rubredoxin, 37 positions are identical, and with the sequences of , , and rubredoxins, 20 matching residues occur. A crystallographic study of the rubredoxin is in progress. 相似文献
3.
The replication defective transducing phage λp3 carries a portion of the operon in the 2 region of the lambda phage. This operon segment contains the promoter, the operator, and the β-galactosidase gene, but does not contain the repressor gene. The gene can be expressed from both the inserted promoter and the phage promoter. When strain 594 (?, +) or JC6256 (Δ) is infected by λp3 in the absence of additional cyclic AMP, β-galactosidase synthesis is shown to be expressed from the phage promoter. When 594 (λ+) or JC6256 (λ+) is infected by λp3 in the presence of additional cyclic AMP and IPTG, β-galactosidase synthesis is shown to be expressed from the inserted promoter.The ability to separate the phage promoter from the inserted promoter for β-galactosidase expression will simplify the interpretation whenever λp5 is used. 相似文献
4.
The site of action of the crinkled (cr) locus was determined by combining dermis and epidermis from the tail of 15-day and mice and by growing the recombined skins in the testes of histocompatible mice. Since mice have bald tails, the presence or absence of hair in the graft was the feature used to determine gene action. Grafts of the combinations dermis and dermis grew hair, whereas grafts of the combinations dermis and dermis produced no hair. It was concluded that the cr locus, at least for tail skin, is active in the epidermis. 相似文献
5.
Two compounds were isolated from female (Lepidoptera: Noctuidae) extracts and identified as -9-tetradecenal and -ll-hexadecenal. Together they elicit intense male . response in laboratory tests and have attracted males in the field. Although -ll-hexadecenal is an . sex pheromone, no evidence was obtained for -9-tetradecenal in . . 相似文献
6.
John C. Sih Roy A. Johnson Eldon G. Nidy David R. Graber 《Prostaglandins & other lipid mediators》1978,15(3):409-421
We wish to report here the syntheses of (5, 6)-5-hydroxy-, (5, 6)-5-hydroxy-, (5, 6)-5-hydroxy-, and (5, 6)-5-hydroxy-PGI1 and their methyl ester derivatives. Treatment of (5, 6)-5-epoxy- and (5, 6)-5-epoxy-PFG1α methyl esters with acid washed silica gel afforded (5, 6)-5-hydroxy- and (5, 6)-5-hydroxy-PGI1 methyl esters; correspondingly, silica promoted cyclization of (5, 6)-epoxy- and (5, 6)-5-epoxy- PGF1 methyl esters yielded (5, 6)-5-hydroxy- and (5, 6)-5-hydroxy- PGI1 methyl esters. Alternatively, the 5-hydroxyl group was introduced into the PGI1 skeleton reaction of the 5-mercuric halides with sodium borohydride in the presence of oxygen. Stereochemical assignments were based on their mode of synthesis and 1H nmr shift differences. 相似文献
7.
Isolation of coccidioides immitis from bat guano and preliminary findings on laboratory infectivity of bats with Coccidioides immitis 总被引:1,自引:0,他引:1
has been isolated from the guano of bats obtained beneath bat roosting places deep within deserted mine tunnels. Certain species of bats have been demonstrated to be susceptible to experimental infection by . There is, however, a difference in the laboratory susceptibility between the species studied ( and ). requires 8 times more arthrospores (400 as compared to 50) than does to produce a defineable infection. Our cultures for in the tissue of produced colonies of the bacterium . Because these tissues were handled under sterile conditions the presence of this red pigment (prodigiosin) producing bacterium was thought not the result of contamination. Prodigiosin suggests a possible mechanism for the apparent greatly reduced susceptibility to . found in the laboratory population of . Skin and serological tests on bats were negative as were cultures of guano from experimentally infected bats and mice. It is speculated that infected dying bats that fall to the floor beneath their roosting sites may contaminate the guano. We of course realize that other animals (we have found and rarely in these tunnels) may have tracked the fungus into these deep tunnel sites. 相似文献
8.
Quantitative electron probe analysis was employed to analyse refractile granules of T. pyriformis individually and in situ. The mean ratios of , , and in granules were similar in cells grown in three different nutrient media. Supplementing the calcium content of proteose-peptone medium with 0.3 and 3 mM calcium depressed the mean ratio and increased the ratio of the granules. The mean ratio and ratio were not significantly altered. When medium M was supplemented with 0.3 mM calcium, there was no significant change in the , , nor ratios. When supplemented with 3 mM Ca, the ratio increased slightly, and the ratio decreased slightly. There was no significant change in the and ratio. When each medium was supplemented with strontium, all granules incorporated this element, probably at the expense of calcium. The ratios in granules in each strontium-containing medium were comparable to the ratio in the granules in strontium-free media, indicating that the mix of divalent ions in granules may vary, but the proportion of divalent ions to phosphorus tends to be uniform. 相似文献
9.
Jean Grandjean Pierre Laszlo 《Biochemical and biophysical research communications》1982,104(4):1293-1297
Transport of Pr3+ across phosphatidylcholine vesicles, monitored through 31P nmr, is first-order in monensin (), second-order in etheromycin () or in lasalocid A (). When and (or and ) are incorporated in 1:1 ratio into the lipidic phase, transport is faster than with each ionophore alone. For instance, assuming that the complexes .Pr3+., .Pr3+., and .Pr3+ are equiprobable, they effect transport at intrinsic relative rates of 1, 2, and 13.5, a remarkable synergism is set up. 相似文献
10.
D M Haverstick D Dickemper A H Gold 《Biochemical and biophysical research communications》1979,87(1):177-183
Cycloheximide given to insulin-treated alloxan diabetic rats results in the inhibition of insulin-induced liver glycogen synthase conversion without affecting the level of synthase . The effect of cycloheximide, believed to elevate cAMP in liver of normal rats, is independent of cAMP levels of the insulin-treated diabetic rat. The inhibition of insulin-mediated synthase to conversion by cycloheximide does not appear to be the result of a cycloheximide-induced cAMP-dependent phosphorylation of synthase to and suggests that insulin control of synthase and interconversions is dependent upon cycloheximide-sensitive protein synthesis. 相似文献
11.
A Novel function of cytochrome C (555, Chlorobium thiosulfatophilum) in oxidation of thiosulfate 总被引:2,自引:0,他引:2
Thiosulfate-cytochrome c-551 reductase derived from has been highly purified. The enzyme reduces cytochrome in the presence of thiosulfate while cytochrome -555 of the organism is not reduced by the enzyme. Cytochrome -555 reacts with the enzyme at an appreciable rate only in the presence of cytochrome -551. However, the reduction rate of cytochrome -551 by the enzyme is greatly enhanced on addition of a catalytic amount of cytochrome -555. Therefore, cytochrome -555 seems to function as an effector on thiosulfate-cytochrome -551 reductase as well as it acts as the electron donor to the light-excited chlorobium chlorophylls. 相似文献
12.
The process of the entry of FITC-conjugated mating factor into -mating type cells of and its concentration into the nucleus were observed. But, when -mating type cells or diploid cells of were incubated with the FITC-conjugated mating factor, its adsorption to the cell surface of the test organisms and its incorporation into the cell did not occur. The peptides formed by the cleavage of mating factor by -mating type cells of were not adsorbed onto -mating type cells. 相似文献
13.
H.R. Bosshard M. Zürrer H. Schägger G. von Jagow 《Biochemical and biophysical research communications》1979,89(1):250-258
Cytochrome 1, the electron donor for cytochrome , is a subunit of the mitochondrial cytochrome 1 complex (complex III, cytochrome reductase). To test if cytochrome 1 is the cytochrome -binding subunit of the 1 complex, binding of cytochrome to the complex and to isolated cytochrome 1 was compared by a gel-filtration method under non-equilibrium conditions (a 1 complex lacking the Rieske ironsulfur protein was used; von Jagow et al. (1977) Biochim. Biophys. Acta , 549–558). The approximate stoichiometries and binding affinities were found to be very similar. Binding of cytochrome to isolated cytochrome which is another subunit of the reductase was not detectable by the gel-filtration method. Further, the same lysine residues of cytochrome were shielded towards chemical acetylation in the complexes 1 and 1. From this we conclude that the same surface area of cytochrome is in direct contact with cytochrome 1 and with cytochrome 1 in the respective complexes and that therefore cytochrome is most probably the structural ligand for cytochrome in mitochondrial cytochrome reductase. 相似文献
14.
The relationship between chromosome replication and the bacterial division cycle has been examined in three substrains of Escherichia coli obtained from different sources and designated A, F and K. At growth rates greater than 1.0 doubling per hour (μ > 1.0), the time for a round of chromosome replication (C) was 42 minutes in all three substrains, but the time between the end of a round and cell division (D) was 22 minutes in A, 16 minutes in F and 14 minutes in K. At slower growth rates C and D increased, but to significantly different extents in the three substrains. When μ = 0.5, C and D were approximately 80 and 40 minutes in A, 60 and 20 minutes in F, and 70 and 20 minutes in K.As a consequence of the lengths of the C and D periods in the three stocks of E. coli, the patterns of chromosome replication during the division cycle differed. The most obvious difference was that E. coli F and E. coli K possessed periods devoid of DNA synthesis at both the beginning and the end of the division cycle during slow growth, whereas E. coli A contained only one period devoid of DNA synthesis at the end of the cycle. 相似文献
15.
The effects of narcotic analgesics, narcotic-antagonist analgesics and narcotic antagonists on ganglionic transmission in the superior cervical ganglia of the rat were studied and . administration of morphine, meperidine, methadone, pentazocine or naltrexone blocked ganglionic transmission. Levorphanol, cyclazocine, nalorphine and naloxone had no effect on ganglionic transmission in this procedure. studies confirmed the results with the exception of levorphanol, cyclazocine and nalorphine, which were also found to block ganglionic transmission . In both preparations, naloxone did not antagonize the effect of morphine, suggesting that the effects of morphine and the other opiates were nonspecific. Similar potency of - and -isomers of pentazocine and cyclazocine support this conclusion. The observation that naltrexone blocked ganglionic transmission, but the other pure narcotic antagonist, naloxone, was inactive is somewhat unique to this test procedure and possibly significant. 相似文献
16.
1-Aminoglycosides represent a new class of specific and relatively potent inhibitors of glycosidases. These compounds are specific against those enzymes which act upon glycosides that correspond to glycone of the inhibitor. Thus α- and β-- are inhibited by -glucosidases but not by -galactosylamine and -mannosylamine. α- and -galactosidases are inhibited by -galactosylamine but not by the other two glycosylamines. -Mannosylamine inhibits mannosidase. 相似文献
17.
C.A. Ruder R.G. Sasser R.J. Williams J.K. Ely R.C. Bull J.E. Butler 《Theriogenology》1981,15(6):573-580
Clinical conditions, which were observed in primiparous Angus and Hereford heifers with postpartum uterine infections are reported. Forty-three of sixty-four cows (67%) had uterine infections. and were the most frequently isolated aerobe and anaerobe, respectively. Twelve of the sixty-four cows (18.8%) had infections that involved these species. Three of these twelve cows were infected only with , two were infected only with , and seven were infected with both organisms. All five of the cows which were infected with either or showed signs of estrus and four of the five cows conceived by 110 days postpartum. The single cow that did not conceive was infected with . Three of the seven cows which were infected with both organisms showed signs of estrus and none of the seven cows conceived by 110 days postpartum. In addition, when only or was isolated from the uterus, cows had either mild or no clinical signs of infection. In contrast, the seven cows which were infected with both organisms had severe clinical signs of infection that included excessive vulvar discharge, uterine abscesses and pelvic adhesions. These observations suggested that a pathogenic synergism between and might have caused the increased severity of postpartum uterine infections, and the subsequent detrimental effect on return to estrus and conception. 相似文献
18.
Controlled alkaline hydrolysis of 16α-bromo-17-keto steroids , and with potassium carbonate and tetra-n-butylammonium hydroxide (n-Bu4NOH) and synthesis of 2α-hydroxy-3-ones , and by the controlled hydrolysis of the corresponding 2α-bromo-3-ones , and are described. Treatm carbonate in aqueous acetone or with n-Bu4NOH in aqueous dimethylformamide (DMF) gave 16α-hydroxy-17-ones , and in 85–90% yield, respectively. 2α-Hydroxy-3-ones , and were obtained by hydrolysis of the corresponding bromoketones , and in high yields using the above conditions or sodium hydroxide in pyridine or DMF, respectively. Deuterium labeling experiments suggested that equilibration between the 2α-bromoketone and the 2β-bromo isomer precedes the formation of the ketol in which the true intermediate might be the 2β-isomer . However, rearranged androstane derivatives, 3β-hydroxy-2-ones and , were stereoselectively obtained by treatment of the bromoketones and with an excess amount of sodium hydroxide. 相似文献
19.
C T Hadden 《Biochemical and biophysical research communications》1973,51(3):501-506
The effect of a deficiency in DNA polymerase on recombination in has been studied. It is concluded that the major DNA polymerase of is not required for recombination, and that the recombination deficiency of a previously described DNA polymerase-deficient mutant is actually due to a mutation. Genetic crosses imply that this recombination deficiency is not or . 相似文献
20.
Peter B. Anzeveno 《Prostaglandins & other lipid mediators》1978,16(1):79-83
Stereosecific synthesis of -hydrindanone , a bicyclic analog of prostaglandin E1, the -hydrindane β-keto ester , is described. When tested in the guinea pig, exhibited no effects on blood pressure and no broncho-constriction or dilation activity. Additionally, failed to inhibit both ADP . 相似文献