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1.
F F Dias M K Shaikh Y B Bhatt D C Modi V R Subramanyam 《The Journal of applied bacteriology》1986,60(4):271-275
Mutants of Bacillus amyloliquefaciens resistant to at least 10 micrograms/ml of tunicamycin were isolated and shown to be pleiotropic. The mutants were more resistant to streptomycin, chloramphenicol, kanamycin and neomycin than was the parent strain but less resistant to penicillin G and tetracycline. They were more autolytic, presumably due to an altered cell wall. The mutants produced reduced levels of amylase, penicillinase and both metal and serine protease besides having an enhanced sporulation frequency and being more motile. 相似文献
2.
The purpose of this study was to determine and compare the follicular phase steroid hormone secretion into the utero-ovarian
vein by the ovary with a dominant follicle and the contralateral ovary in the same baboon. Serial utero-ovarian vein blood
from both sides was collected in 25 baboons by the use of a laparoscope on alternate days, starting on day 1 or 3 of the cycle
and continuing through 2 to 3 days post-ovulation. Approximately 3–4 days before the day of expected ovulation, samples were
collected at 8-hr intervals. Steroids estradiol (E2) and progesterone (P) were measured in all utero-ovarian vein plasma by radioimmunoassay. In the peripheral plasma, E2, P, LH, and FSH measurements were carried out. Concentrations of steroids were significantly higher on the side of the ovulating
ovary by day 5 before ovulation. Individual plots however, indicated that some baboons may establish the dominant side as
early as day 11 before ovulation. The preovulatory gonadotropins had a differential effect on the two ovaries. For example,
E2 values on the ovulatory side ovary declined after increases in LH/FSH, whereas on the contralateral side these values had
increased. Both sides showed increases in the level of P with the increases in LH. The mean interval from E2 peak to LH peak was 24 hrs and LH peak to ovulation was 24 hrs. 相似文献
3.
L G Hudson R Shaikh W A Toscano W F Greenlee 《Biochemical and biophysical research communications》1983,115(2):611-617
The responsiveness of 5 human squamous cell carcinoma (SCC) lines derived from tumors of the epidermis and tongue to 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD) was assessed by measuring the induction of the cytochrome P1-450-mediated monooxygenase activity, 7-ethoxycoumarin O-deethylase (ECOD). In 4 of the SCC lines the EC50 for this response was approximately 10(-9)M, whereas in one line the EC50 was 10(-10)M. In each of the less sensitive lines a concentration of 10(-10)M TCDD elicited less than 5% of the maximal enzyme activity. Specific binding of radiolabeled TCDD was detected in the cytosol fraction from all the SCC lines. The relative amount of receptor measured in each line correlated with maximally-induced ECOD activity. The data indicate that human cell lines derived from a target tissue for TCDD toxicity contain the TCDD receptor and show differential sensitivity to TCDD analogous to the murine strain differences in sensitivity regulated by the Ah locus. 相似文献
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6.
Gerald J. Putterman Badaruddin Shaikh Margarette R. Hallmark Cheryl G. Sawyer Catherine V. Hixson Fulvio Perini 《Analytical biochemistry》1979,98(1):18-26
Procedures are presented for the simultaneous analysis of hypoxanthine, xanthine, allopurinol, oxipurinol, and uric acid in standard mixtures and physiological fluids using gas chromatography (gc) or high-pressure liquid chromatography (hplc). Excellent correlation was obtained between the two methods for hypoxanthine, xanthine, oxipurinol, and uric acid. There are advantages and disadvantages to both methods. hplc requires no prior derivatization, uses isocratic elution with a buffer containing no organic solvent, and has 50- to 100-fold greater sensitivity than gc. Simpler methods of prepurification, readily adapted to clinical laboratories, can be used for hplc analysis. Although substances that are found in some urine samples from cancer patients interfere with hplc, separations by gc are not affected by these substances. 相似文献
7.
Summary The effect of growth at 30°, 35° and 40° on the biomass yield and on the nucleic acid and protein content of twelve isolates of yeast has been studied. Although yields of 41.6% and a true protein content of 34% were obtained, each of the strains exhibited a lower yield and protein content at 40° than at the lower temperatures. Nucleic acid levels were also reduced at 40°. 相似文献
8.
Penicillin amidohydrolase productivity of four locally isolated bacterial species is described. Organisms were identified
asEscherichia coli, Pseudomonas aeruginosa, Sarcina lutea andBacillus megaterium. Highest enzyme productivity of 3.2 U/mL with a corresponding dry cell mass of 4.5 g/L was recorded fromS. lutea. 相似文献
9.
Extraction of whole lobes of normal rat liver with dimethyl sulphoxide (DMSO) under N2 gives extracts which contain 5—10 μmol/l·O?2 (50-100 nmol·O?2 per 10 ml extract per 4 g liver; 1.25-2.50 nmol·O?2 per millilitre per gram liver). Evidence for ·O?2 in the extracts is given by: (1) electron spin resonance signals (ESR), (2) differential pulse polarography (DPP), (3) chemiluminescence (CL), and (4) nitroblue tetrazolium reduction (NBT). All tests yield results identical with those obtained with authentic ·O?2. Extraction of ·O?2 is enhanced by tetrabutyl ammonium ion, and is maximal at 1-3 min. These results raise the possibility that substantial amounts of ·O?2 are normally sequestered in protective membranous sites in vivo. 相似文献
10.
The administration of inorganic Cd and Hg in vivo has been shown to result in markedly different metal concentrations in rat liver. Primary cultures of rat hepatocytes were utilized to gain insight into the dispositional differences between these chemically similar metals. Hepatocyte monolayer cultures were exposed to several concentrations of Cd or Hg (3, 10 and 30μm) in serum-containing medium for 30min. The cells were then washed and incubated in fresh medium for the remainder of the experiment. Hepatocytes exposed to Cd accumulated significantly more metal than hepatocytes exposed to equimolar concentrations of Hg. In cells exposed to 3μm-Cd there was an initial loss of Cd from the hepatocytes when placed in fresh medium, followed by a gradual re-uptake of metal, concomitant with increased binding to metallothionein. In hepatocytes exposed to 3 and 10μm-Cd, 87 and 77% of the intracellular Cd was bound to metallothionein within 24h. Loss of Hg from hepatocytes pulsed with 30μm-Hg was also observed upon the addition of fresh medium and continued for the duration of the experiment. No time-dependent increase in Hg binding to metallothionein was observed. A maximum of about 10% of the intracellular Hg was found associated with metallothionein in hepatocytes exposed to 30μm-Hg. Studies utilizing [35S]cysteine incorporation indicated significant increases in the amount of metallothionein synthesized in hepatocytes exposed to 3 and 10μm-Cd (300% of control value) and 30μm-Hg (150% of control value) 24h after metal pulsing. Time-course studies revealed a 6–12h lag in metallothionein synthesis, followed by a significant elevation in [35S]cysteine incorporation into metallothionein between 12 and 24h. These studies suggest that (a) isolated hepatocytes differentiate between Cd and Hg and preferentially accumulate the former, and (b) Cd strongly stimulates the induction of, and preferentially binds to, metallothionein, whereas Hg induces weakly, and does not preferentially bind to, metallothionein. 相似文献