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11.
Cadmium- and mercury-resistant Bacillus strains from a salt marsh and from Boston Harbor 总被引:2,自引:0,他引:2
I Mahler H S Levinson Y Wang H O Halvorson 《Applied and environmental microbiology》1986,52(6):1293-1298
Bacteria resistant to cadmium or mercury or both were isolated from the Great Sippewissett Marsh (Cape Cod, Mass.) and from Boston Harbor. Many of these metal-resistant isolates were gram-positive aerobic sporeformers, although not necessarily isolated as spores. Although several of the isolated strains bore plasmids, cadmium and mercury resistances appeared to be, for the most part, chromosomally encoded. DNA sequence homology of the gram-positive cadmium- and mercury-resistant isolates was not demonstrable with metal resistance genes from plasmids of either gram-positive (pI258) or gram-negative (pDB7) origin. Cadmium resistance of all the marsh isolates tested resulted from reduced Cd2+ transport. On the other hand, three cadmium-resistant harbor isolates displayed considerable influx but no efflux of Cd2+. Hg-resistant strains detoxified mercury by transforming Hg2+ to volatile Hg0 via mercuric reductase. 相似文献
12.
H R Mahler L R Jones W J Moore 《Biochemical and biophysical research communications》1971,42(3):384-389
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Antagonism of insulin action on muscle by the albumin-bound B chain of insulin 总被引:1,自引:0,他引:1
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1. The presence of a substance associated with human albumin that exerts anti-insulin activity on the isolated rat diaphragm has been confirmed. This factor has been removed from albumin, thereby providing a source of non-antagonistic carrier protein. 2. Derivatives of the polypeptide B chain of insulin obtained by chemical scission of the interchain disulphide bonds have been separated by conventional techniques. In the presence of non-antagonistic albumin, the reduced and sulpho-B chain preparations inhibited insulin action on muscle. 3. The B chain resulting from reductive cleavage of insulin by bovine-liver extracts, in association with human albumin, exhibited a comparable anti-insulin effect. 4. It is postulated that the B chain interacts with albumin to enable solubilization of the chain and that inhibition of insulin action on muscle may occur as a result of competition for cellular receptor sites by the B chain. 5. The implication of these findings in relation to a circulating insulin antagonist is discussed. 相似文献
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Chlorella sp. strain 3.83, a symbiotic Chlorella isolated from the heliozoan Acanthocystis turfacea, excreted between 8% and 16% of assimilated 14CO2 as maltose in the light (15000 lx), with a pH optimum around 4.8. This percentage increased when the illuminance was lowered (36% at 1700 lx). Release of [14C]maltose continued in darkness and could be inhibited by the uncoupler carbonyl cyanide p-trifluoro-methoxyphenylhydrazone and by diethylstilbestrol. Net efflux of maltose was observed even at a concentration ratio of extracellular/intracellular maltose of 7.8. Exogenous [14C]maltose (5 mM) was taken up by the cells with a rate <2% of that of simultaneous maltose release, indicating a practically unidirectional transport. It is concluded that maltose excretion is an active-transport process.Abbreviations DES
diethylstilbestrol
- FCCP
carbonyl cyanide p-trifluoromethoxyphenyl hydrazone
- p.c.
packed cells
This work was supported by the Deutsche Forschungsgemeinschaft. Thanks are due to Doris Meindl for skillful experimental help. 相似文献
17.
Comparison of OspA Serotypes for Borrelia burgdorferi Sensu Lato from Japan,Europe and North America
Toshiyuki Masuzawa Bettina Wilske Tetsuro Komikado Hiroyuki Suzuki Hiroki Kawabata Nanao Sato Koichi Muramatsu Nobutake Sato Emiko Isogai Hiroshi Isogai Russell C. Johnson Yasutake Yanagihara 《Microbiology and immunology》1996,40(8):539-545
Sixty-one Borrelia burgdorferi sensu lato strains from various sources (ticks, human, and wild animals) in Japan and two strains from ticks in Far Eastern Russia were classified on the basis of reactivity with 16 monoclonal antibodies (mAb) to outer surface protein A (OspA) and by DNA-DNA hybridization assay. Eleven OspA serotypes (J1 to J11) were recognized among the Japanese and the Far East Russian isolates (serotypes J1 to J9 were identified as B. garinii, serotype J10 was identified as B. afzelii, and serotype J11 corresponded to B. japonica), whereas 7 OspA serotypes for North American and European isolates previously reported (Bettina Wilske et al, J. Clin. Microbiol. 31:340-350, 1993) were not observed except for OspA serotype 2 which showed identical reactivity with OspA serotype J10. This finding provides helpful information for understanding the geographical distribution of Lyme disease borrelia and the development of vaccine and diagnostic tests. In conclusion: 1. B. burgdorferi sensu stricto has not been observed in Japan, 2. Japanese B. afzelii isolates are closely related to those from Europe, 3. B. garinii isolates from Japan are highly heterogeneous and apparently different from European B. garinii isolates. 相似文献
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19.
ZmHox: a novel class of maize homeobox genes 总被引:2,自引:0,他引:2
Bettina Klinge Bärbel Überlacker Christian Korfhage Wolfgang Werr 《Plant molecular biology》1996,30(3):439-453
20.
Human follicle stimulating hormone is a pituitary glycoprotein that is essential for the maintenance of ovarian follicle development and testicular spermatogenesis. Like other members of the glycoprotein hormone family, it contains a common a subunit and a hormone specific subunit. Each subunit contains two glycosylation sites. The specific structures of the oligosaccharides of human follicle stimulating hormone have been shown to influence both thein vitro andin vivo bioactivity. Since the carbohydrate structure of a protein reflects the glycosylation apparatus of the host cells in which the protein is expressed, we examined the isoform profiles,in vitro bioactivity and metabolic clearance of a preparation of purified recombinant human follicle stimulating hormone derived from a stable, transfected Sp2/0 myeloma cell line, and pituitary human follicle stimulating hormone. Isoelectric focussing and chromatofocussing studies of human follicle stimulating hormone preparations both showed a more basic isoform profile for the recombinant human follicle stimulating hormone compared to that of pituitary human follicle stimulating hormone. The recombinant human follicle stimulating hormone had a significantly higher radioreceptor activity compared to that of pituitary human follicle stimulating hormone, consistent with a greaterin vitro potency. Pharmacokinetic studies in rats indicated a similar terminal half life (124 min) to that of the pituitary human follicle stimulating hormone (119 min). Preliminary carbohydrate analysis showed recombinant human follicle stimulating hormone to contain high mannose and/or hybrid type, in addition to complex type carbohydrate chains, terminating with both2,3 and2,6 linked sialic acids. These results demonstrate that recombinant human follicle stimulating hormone made in the Sp2/0 myeloma cells is sialylated, has a more basic isoform profile, and has a greaterin vitro biological potency compared to those of the pituitary human follicle stimulating hormone. 相似文献