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51.
Nucleotide sequence, organisation and structural analysis of the products of genes in the nirB-cysG region of the Escherichia coli K-12 chromosome 总被引:12,自引:0,他引:12
T Peakman J Crouzet J F Mayaux S Busby S Mohan N Harborne J Wootton R Nicolson J Cole 《European journal of biochemistry》1990,191(2):315-323
The DNA sequence and derived amino-acid sequence of a 5618-base region in the 74-min area of the Escherichia coli chromosome has been determined in order to locate the structural gene, nirB, for the NADH-dependent nitrite reductase and a gene, cysG, required for the synthesis of the sirohaem prosthetic group. Three additional open reading frames, nirD, nirE and nirC, were found between nirB and cysG. Potential binding sites on the NirB protein for NADH and FAD, as well as conserved central core and interface domains, were deduced by comparing the derived amino-acid sequence with those of database proteins. A directly repeated sequence, which includes the motif -Cys-Xaa-Xaa-Cys-, is suggested as the binding site for either one [4Fe-4S] or two [2Fe-2S] clusters. The nirD gene potentially encodes a soluble, cytoplasmic protein of unknown function. No significant similarities were found between the derived amino-acid sequence of NirD and either NirB or any other protein in the database. If the nirE open reading frame is translated, it would encode a 33-amino-acid peptide of unknown function which includes 8 phenylalanyl residues. The product of the nirC gene is a highly hydrophobic protein with regions of amino-acid sequence similar to cytochrome oxidase polypeptide 1. 相似文献
52.
The evolution of life histories: Theory and analysis 总被引:2,自引:0,他引:2
R. J. Wootton 《Reviews in Fish Biology and Fisheries》1993,3(4):384-385
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A. J. Allsopp R. Sutherland P. Wood S. A. Wootton 《European journal of applied physiology and occupational physiology》1998,78(6):516-521
The effect of manipulating sodium intake upon sweat sodium secretion was investigated during heat acclimation. Twenty-five
male subjects were confined to an environmental chamber at a temperature of 25°C for 3 days, and then acclimated to heat by
a further 5 days at 40°C. The subjects' daily sodium intake was controlled throughout as follows: high (HNa), 348.4 (0.8) mmol · day−1, n = 7; moderate (MNa), 174.1 (0.6) mmol · day−1, n = 9; or low (LNa), 66.3 mmol · day−1, n = 9. Sodium losses were estimated from urinary, faecal and sweat collections using a whole-body washdown method. Plasma aldosterone
concentration was also measured from venous blood sampled each morning. Measurements of body temperature and heart rate during
the heat exposure phase indicated a degree of heat acclimation. During this heat phase there was a reduction (P < 0.01) in sweat sodium secretion for all three conditions which was greatest for the LNa condition, although this finding
was not significant (P < 0.1). In the LNa condition, plasma aldosterone concentration increased (P < 0.05) prior to heat exposure, and the secretion of aldosterone was potentiated (P < 0.01) during the heat exposure in comparison with the MNa condition. In contrast, the HNa diet produced a fall (P < 0.05) in plasma aldosterone concentration prior to heat exposure and an attenuation of aldosterone secretion thereafter.
These findings are inconsistent with the hypothesis that retention of sweat sodium is dependent upon a net body sodium deficit,
but demonstrate that aldosterone secretion is potentiated under such conditions.
Accepted: 22 May 1988 相似文献
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LL. Lloyd 《The Annals of applied biology》1943,30(4):358-364
The incidence of the sewage fly, Psychoda alternata Say, breeding almost free from other insect competitors in a bacteria bed at Huddersfield is examined. Its general seasonal trend is marked by periods of peak output explained on the theory that there are two successions of generations running persistently and alternating with one another. Such behaviour has previously been demonstrated for another sewage fly, Spaniotoma minima , and has been shown to be instituted by irregular temperatures in autumn and spring. In Psychoda alternata a special type of intraspecific competition is set-up in the warmer months when the cycles are rapid, for the larvae of one succession must start life in a bed just depleted of food by the other. Therefore large and small outbursts of the fly tend to alternate. The discharges of solids from the bed have a detailed periodicity corresponding to the alternations in the successions of the fly. 相似文献
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