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1.
Robert Blake II Elizabeth A. Shute James Waskovsky Arthur P. Harrison JR. 《Geomicrobiology journal》2013,30(3-4):173-192
Abstract Microorganisms capable of aerobic respiration on ferrous ions are spread throughout eubacterial and archaebacterial phyla. Phylogenetically distinct organisms were shown to express spectrally distinct redox‐active biomolecules during autotrophic growth on soluble iron. A new iron‐oxidizing eubacterium, designated as strain Funis, was investigated. Strain Funis was judged to be different from other known iron‐oxidizing bacteria on the bases of comparative lipid analyses, 16S rRNA sequence analyses, and cytochrome composition studies. When grown autotrophically on ferrous ions, Funis produced conspicuous levels of a novel acid‐stable, acid‐soluble yellow cytochrome with a distinctive absorbance peak at 579 nm in the reduced state. Stopped‐flow spectrophotometric kinetic studies were conducted on respiratory chain components isolated from cell‐free extracts of Thiobacillus ferrooxidans. Experimental results were consistent with a model where the primary oxidant of ferrous ions is a highly aggregated c‐type cytochrome that then reduces the periplasmic rusticyanin. The Fe(II)‐dependent, cytochrome c‐catalyzed reduction of the rusticyanin possessed three kinetic properties in common with corresponding intact cells that respire on iron: the same anion specificity, a similar dependence of the rate on the concentration of ferrous ions, and similar rates at saturating concentrations of ferrous ions 相似文献
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Moment-based criteria for determining bioequivalence 总被引:1,自引:0,他引:1
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J. Crossa C. O. Gardner 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1989,77(1):33-38
Summary The maize (Zea mays L.) improvement program of the International Maize and Wheat Improvement Center (CIMMYT) develops broad-based maize populations and, until recently, improved all of them through full-sib family selection with international testing. The purpose of this study was to estimate the genetic and genetic × environment variance components for ten of those populations and to measure expected yield improvement from full-sib selection. Mean yield ranged from 3.35–6.81 t ha–1. For five populations the average yield in the last cycle was higher than in the initial cycles. Several populations showed no improvement or yielded less in the final cycle of selection, either because selection intensity was low or because strong selection pressure was applied simultaneously for several traits. Variation resulting from differences among family means within cycles and from interaction between families and locations within cycles were significant in all populations and cycles. Results indicate that variability among full-sib families was maintained throughout the cycles for all populations. The large
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ratio shown by most populations suggests that yield response per cycle could be maximized if the environments in which progenies are tested were subdivided and classified into similar subsets. The proportion of the predicted response realized in improved yield varied for each population.Journal Paper No. 8640, Nebraska Agric. Res. Div. Project No. 12-159. Research was supported in part by USAID/USDA/ CSRS Research Grant No. 86-CRSR-2-2789 相似文献
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S. Ellner 《Journal of mathematical biology》1989,27(4):451-462
Two sets of sufficient conditions are given for convergence to stationary distributions, for some general models of two species competing in a randomly varying environment. The models are nonlinear stochastic difference equations which define Markov chains. One set of sufficient conditions involves strong continuity and -irreducibility of the transition probability for the chain. The second set has a much weaker irreducibility condition, but is only applicable to monotonic models. The results are applied to a stochastic two-species Ricker model, and to Chesson's lottery model with vacant space, to illustrate how the assumptions can be checked in specific models. 相似文献
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The best evidence for identifying the inhabitants of northeast Asia in the terminal Pleistocene or early Holocene periods is provided by the human burials from the Upper Cave at Zhoukoudian, and in particular the “Old Man”. Apart from the Minatogawa finds on Okinawa, all Late Pleistocene human remains from East Asia that are reasonably well published are poorly preserved and often have equivocal dates. Since the time the Upper Cave was excavated it has been supposed that the human remains were the link between “Peking Man” and the modern Mongoloid complex. We have carried out multivariate analyses of the “Old Man” cranium employing new measurements of Weidenreich's cast of the skull and comparative data from Howells' survey of modern human groups. Despite our expectations the analyses have not shown the “Old Man” to be closely linked with the Mongoloids. Considering all the evidence available we conclude that the common belief of a close biological relationship between the people buried in the Upper Cave and the modern Mongoloids is not yet adequately demonstrated. Of crucial importance in interpreting the Upper Cave burials is their antiquity, which is still commonly thought to be in the order of at least 18 000 years. We believe that recent C-14 dates of about 11 000 years, determined from animal bones, indicate the earliest possible date for the burials. The time span between the Upper Cave burials and the earliest known modern Mongoloids in north China is in the order of about 4–5000 years. It is possible that a major population shift has occurred in north China between the terminal Pleistocene and the mid Holocene, when farming first appears. If this is so, the Upper Cave people may not have been closely allied to the Mongoloid groups that now inhabit East Asia and the Americas. 相似文献
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M. R. Naidu P. Singh B. S. Dahiya 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1988,75(3):514-517
Summary Selection in the F3 generation for seed yield, fruiting branches/plant, effective pods/plant, and seed index (100-seed weight) was carried out in two chickpea crosses. Sixty F5 lines (15 lines/selection criterion) along with check variety were evaluated for seed yield in three distinct environments. The effects of selection criteria on yield stability was examined using linear regression approach and genotype-grouping technique. There were no differences between selection criteria for linear yield responses of F5 lines to different environments. Within all four selection criteria the lines showed similar linear responses. The non-linear component was relatively higher for lines selected for effective pods and seed index than lines selected for yield and fruiting branches. On the basis of mean yield and coefficient of variation across environments, the seed index was the least effective selection criterion for developing high yielding and stable lines. When the results of stability parameters and genotype-grouping technique were considered together, selection for yield and fruiting branches was highly effective for isolating stable and high yielding lines. 相似文献
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G. S. Mahal K. S. Gill G. S. Bhullar 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1988,76(3):438-442
Summary Twelve durum wheat varieties originating from 3 ecologically diverse regions and their 48 intergroup crosses were evaluated for stability of performance with respect to grain yield and certain component traits. The linear component of the genotype-environment interaction was revealed for grain yield, 100-grain weight and plant height, non-linear for tiller number whereas for grains per spike both components were equally important. However, except for tiller number, the linear component appeared to be contributing to a large extent towards the prevalent interactions. NP 404, Bijaga Yellow and Giorgio VZ 331 depicted stable performance for grain yield. However, considering all the attributes, the parents NP 404, Bijaga Yellow, Anhinga s and Mexicali 75 and hybrids NP 401 x Mexicali 75, NP 404 x Anhinga s, NP 412 x Mexicali 75, NP 404 x Gerardo VZ 466 and Anhinga s x Capeiti appeared promising. The Mexican group as a whole exhibited a more stable performance than the other two evaluated groups. Compensating shift among the component characters was evident in the case of parents as well as hybrids and stability of performance appeared to be under genetic control. Effective utilization of these two aspects through introduction in otherwise desirable varieties has been advocated.Part of Ph.D. thesis of senior author submitted to the Punjab Agricultural University 相似文献