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151.
W. Y. Cheung T. A. Money S. Abbo K. M. Devos M. D. Gale G. Moore 《Molecular & general genetics : MGG》1994,245(3):349-354
A family of related sequences associated with (TTTAGGG)
n
repeats has been cloned from the wheat cultivar Chinese Spring. These sequences reveal a high level of polymorphism between wheat varieties when used as restriction fragment length polymorphism (RFLP) probes. Although this family of sequences contains motifs homologous to the repeats in the telomeres of wheat, they are located at interstitial sites on wheat chromosomes. 相似文献
152.
Hans Kuhn 《Biosensors & bioelectronics》1994,9(9-10):707-717
Some goals of bioelectronics—interfacing biology and electronics — are the understanding of supramolecular bioprocesses and the construction of supramolecular devices. The principles for the design and fabrication of machineries with functional components of molecular size are inspired by reflecting on biosystems, and it seems important to consider such principles. We first discuss attempts to construct supramolecular machines, and then we consider the bacterial reaction centre as an example where supramolecular engineering helps to elucidate a bioprocess. We then discuss possible mechanisms leading to the emergence of life-like systems in the light of the basic principles used to design supramolecular devices. Finally, we reflect on prospects in molecular engineering inspired by studying the emergence of life-like systems. 相似文献
153.
Comparison of the intermediate complexes of human growth hormone bound to the human growth hormone and prolactin receptors. 总被引:4,自引:2,他引:2
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A. A. Kossiakoff W. Somers M. Ultsch K. Andow Y. A. Muller A. M. De Vos 《Protein science : a publication of the Protein Society》1994,3(10):1697-1705
The crystal structures of complexes of human growth hormone (hGH) with the growth hormone and prolactin receptors (hGHR and hPRLR, respectively), together with the mutational data available for these systems, suggest that an extraordinary combination of conformational adaptability, together with finely tuned specificity, governs the molecular recognition processes operative in these systems. On the one hand, in the active 1:2 ligand-receptor complexes, 2 copies of the same receptor use the identical set of binding determinants to recognize topographically different surfaces on the hormone. On the other hand, comparing the 1:1 hGH-hGHR and hGH-hPRLR complexes, 2 distinct receptors use this same set of binding determinants to interact with the identical binding site on the ligand, even though few residues among the binding determinants are conserved. The structural evidence demonstrates that this versatility is accomplished by local conformational flexibility of the binding loops, allowing adaptation to different binding environments, together with rigid-body movements of the receptor domains, necessary for the creation of specific interactions with the same binding site. 相似文献
154.
DNA sequencing with arbitrary primer pairs 总被引:8,自引:0,他引:8
155.
A physical map and clone bank of the black pine (Pinus thunbergii) chloroplast genome 总被引:1,自引:1,他引:0
T. Wakasugi J. Tsudzuki S. Ito M. Shibata M. Sugiura 《Plant Molecular Biology Reporter》1994,12(3):227-241
Black pine chloroplast DNA is 119,707 bp long. The physical map is shown and the genes are listed. Plasmid clones covering
the entire DNA sequence have been ordered and available upon request. 相似文献
156.
Lora Swenson Ruth Green Rolf Joerger Michael Haas Karen Scott Yunyi Wei Urszula Derewenda David M. Lawson Zygmunt S. Derewenda 《Proteins》1994,18(3):301-306
A neutral lipase from the filamentous fungus Rhizopus delemar has been crystallized in both its proenzyme and mature forms. Although the latter crystallizes readily and produces a variety of crystal forms, only one was found to be suitable for X-ray studies. It is monoclinic (C2, a = 92.8 Å, b = 128.9 Å, c = 78.3 Å, β = 135.8) with two molecules in the asymmetric unit related by a noncrystallographic diad. The prolipase crystals are orthorhombic (P212121, with a = 79.8 Å, b = 115.2 Å, c = 73.0 Å) and also contain a pair of molecules in the asymmetric unit. Initial results of molecular replacement calculations using the refined coordinates of the related lipase from Rhizomucor miehei identified the correct orientations and positions of the protein molecules in the unit cells of crystals of both proenzyme and the mature form. © 1994 John Wiley & Sons, Inc. 相似文献
157.
158.
John L. Wray 《Physiologia plantarum》1993,89(3):607-612
Nitrite reductase (ferredoxin:nitrite oxidoreductase, EC 1.6.6.1) carries out the six-electron reduction of nitrite to ammonium ions in the chloroplasts/plastids of higher plants. The complete or partial nucleotide sequences of a number of nitrite reductase apoprotein genes or cDNAs have been determined. Deduced amino acid sequence comparisons have identified conserved regions, one of which probably is involved in binding the sirohaem/4Fe4S centre and another in binding the electron donor, reduced ferredoxin. The nitrite reductase apoprotein is encoded by the nuclear DNA and is synthesised as a precursor carrying an N-terminal extension, the transit peptide, which acts to target the protein to, and within, the chloroplast/plastid. In those plants examined the number of nitrite reductase apoprotein genes per haploid genome ranges from one (barley, spinach) to four ( Nicotiana tabacum ). Mutants defective in the nitrite reductase apoprotein gene have been isolated in barley. During plastidogenesis in etiolated plants, synthesis of nitrite reductase is regulated by nitrate, light (phytochrome), and an uncharacterised 'plastidic factor' produced by functional chloroplasts. In leaves of green, white-light-grown plants up-regulation of nitrite reductase synthesis is achieved via nitrate and light and down-regulation by a nitrogenous end-product of nitrate assimilation, perhaps glutamine. A role for phytochrome has not been demonstrated in green, light-grown plants. Light regulation of nitrite reductase genes is related more closely to that of photosynthetic genes than to the nitrate reductase gene. In roots of green, white-light-grown plants nitrate alone is able to bring about synthesis of nitrite reductase, suggesting that the root may possess a mechanism that compensates for the light requirement seen in the leaf. 相似文献
159.
Longitudinal patterns of dissolved organic carbon concentration and suspended bacterial density along a blackwater river 总被引:2,自引:0,他引:2
Dissolved organic carbon (DOC) is the dominant form of carbon in transport in blackwater rivers, and bacteria are the major
biological agents of its utilization. This study describes longitudinal patterns in DOC concentration and relates them to
suspended bacterial populations in the channel. Concentrations of total DOC, three molecular weight fractions, and bacterial
numbers were determined at 12 sites along the Ogeechee River in 1985–1986 and 1989 during periods of low and high discharge.
Suspended bacterial populations were compared with DOC concentrations to determine if differences in bacterial abundance were
related to longitudinal patterns of DOC concentration. Three distinct longitudinal patterns were observed: (1) The longitudinal
pattern followed by both total and intermediate molecular weight DOC concentrations was a linear function of the geographic
distance along the river. (2) During low flow conditions, there was a high degree of correspondence between patterns of bacterial
numbers and low MW DOC (< 1000 apparent MW). (3) During periods of high discharge, the proportion of high (> 10,000) and intermediate
(1000–10,000) MW fractions increased, and there was no longer a clear relationship between bacterial cells and low MW DOC. 相似文献
160.
S. Fauré J. L. Noyer J. P. Horry F. Bakry C. Lanaud D. Gońzalez de León 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1993,87(4):517-526
A partial molecular linkage map of the Musa acuminata diploid genome is presented. This map is based on 58 RFLP, four isozyme and 28 RAPD markers segregating in an F2 population of 92 individuals. A total of 90 loci was detected, 77 of which were placed on 15 linkage groups while 13 segregated independently. Segregation distortions were shown by 36% of all loci, mostly favoring the male parent. Chromosome structural rearrangements were believed to be one of the main causes of these distortions. The use of genetic linkage data to further the genetic and evolutionary knowledge of the genus Musa, as well as to help improve the design of breeding strategies, is discussed. 相似文献