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71.
Djian P; Phillips M; Easley K; Huang E; Simon M; Rice RH; Green H 《Molecular biology and evolution》1993,10(6):1136-1149
The involucrin genes of the mouse (Mus musculus) and the rat (Rattus
norvegicus) have been cloned and sequenced. The coding region of each gene
contains, at site P, a segment of repeats homologous to that of other
nonanthropoid mammals. In contrast to the repeats of species belonging to
different mammalian orders, many individual repeats of the mouse and the
rat can be matched. Both before and after the divergence of the two
species, these repeats have been the site of systematic alterations in
nucleotide sequence. One of the alterations is the correction of
nucleotides of one repeat by those of another. Corrected nucleotides may be
closely linked to flanking nucleotides that are uncorrected; the systematic
correction process therefore appears to be due to gene conversion. There is
a stretch of 18 reiterated CAGs in the segment of repeats of the Mus gene;
most of these reiterations were introduced recently, supporting the idea
that the gene was generated originally from poly CAG. An antiserum to a
synthetic peptide encoded by the segment of repeats of the Mus gene reveals
differentiation- specific expression of the gene in the epidermis.
相似文献
72.
Purification and Molecular Characterization of the Brain Synaptic Membrane Glutamate-Binding Protein 总被引:8,自引:7,他引:1
Elias K. Michaelis Mary L. Michaelis Thomas M. Stormann W. Leroy Chittenden Robert D. Grubbs 《Journal of neurochemistry》1983,40(6):1742-1753
A glutamate-binding protein from rat brain synaptic plasma membranes has been purified to apparent homogeneity. This protein has a Mr of 14,300 based on amino acid and carbohydrate analyses. The protein is enriched with tryptophan residues, which contribute substantially to its hydrophobic nature. It also has a relatively high content of acidic amino acids, which determine is low isoelectric point (4.82). The protein exhibits either a single, high-affinity class of sites for L-[3H]glutamate binding (KD = 0.13 microM) when binding is measured at low protein concentrations, or two classes of sites with high (KD = 0.17 microM) and low affinities (KD = 0.8 microM) when binding is measured at high protein concentrations. These observations suggest preferential binding of L-glutamate to a self-associating form of the protein. The displacement of protein-bound L-[3H]glutamic acid by other neuroactive amino acids has characteristics similar to those observed for displacement of L-glutamate from membrane binding sites. Chemical modification of the cysteine and arginine residues results in an inhibition of glutamate binding activity. The possible function of this protein in the physiologic glutamate receptor complex of neuronal membranes is discussed. 相似文献
73.
Lauren RH Krumpe Kathryn M Schumacher James B McMahon Lee Makowski Toshiyuki Mori 《BMC biotechnology》2007,7(1):65
Background
Amino acid sequence diversity is introduced into a phage-displayed peptide library by randomizing library oligonucleotide DNA. We recently evaluated the diversity of peptide libraries displayed on T7 lytic phage and M13 filamentous phage and showed that T7 phage can display a more diverse amino acid sequence repertoire due to differing processes of viral morphogenesis. 相似文献74.
75.
Cedar M. Chittenden Carlo A. Biagi Jan Grimsrud Davidsen Anette Grimsrud Davidsen Hidehiro Kondo Allison McKnight Ole-Petter Pedersen Peter A. Raven Audun H. Rikardsen J. Mark Shrimpton Brett Zuehlke R. Scott McKinley Robert H. Devlin 《PloS one》2010,5(8)
With the current trends in climate and fisheries, well-designed mitigative strategies for conserving fish stocks may become increasingly necessary. The poor post-release survival of hatchery-reared Pacific salmon indicates that salmon enhancement programs require assessment. The objective of this study was to determine the relative roles that genotype and rearing environment play in the phenotypic expression of young salmon, including their survival, growth, physiology, swimming endurance, predator avoidance and migratory behaviour. Wild- and hatchery-born coho salmon adults (Oncorhynchus kisutch) returning to the Chehalis River in British Columbia, Canada, were crossed to create pure hatchery, pure wild, and hybrid offspring. A proportion of the progeny from each cross was reared in a traditional hatchery environment, whereas the remaining fry were reared naturally in a contained side channel. The resulting phenotypic differences between replicates, between rearing environments, and between cross types were compared. While there were few phenotypic differences noted between genetic groups reared in the same habitat, rearing environment played a significant role in smolt size, survival, swimming endurance, predator avoidance and migratory behaviour. The lack of any observed genetic differences between wild- and hatchery-born salmon may be due to the long-term mixing of these genotypes from hatchery introgression into wild populations, or conversely, due to strong selection in nature—capable of maintaining highly fit genotypes whether or not fish have experienced part of their life history under cultured conditions. 相似文献
76.
Cedar M. Chittenden Jenny L. A. Jensen David Ewart Shannon Anderson Shannon Balfry Elan Downey Alexandra Eaves Sonja Saksida Brian Smith Stephen Vincent David Welch R. Scott McKinley 《PloS one》2010,5(8)
As the timing of spring productivity blooms in near-shore areas advances due to warming trends in global climate, the selection pressures on out-migrating salmon smolts are shifting. Species and stocks that leave natal streams earlier may be favoured over later-migrating fish. The low post-release survival of hatchery fish during recent years may be in part due to static release times that do not take the timing of plankton blooms into account. This study examined the effects of release time on the migratory behaviour and survival of wild and hatchery-reared coho salmon (Oncorhynchus kisutch) using acoustic and coded-wire telemetry. Plankton monitoring and near-shore seining were also conducted to determine which habitat and food sources were favoured. Acoustic tags (n = 140) and coded-wire tags (n = 266,692) were implanted into coho salmon smolts at the Seymour and Quinsam Rivers, in British Columbia, Canada. Differences between wild and hatchery fish, and early and late releases were examined during the entire lifecycle. Physiological sampling was also carried out on 30 fish from each release group. The smolt-to-adult survival of coho salmon released during periods of high marine productivity was 1.5- to 3-fold greater than those released both before and after, and the fish''s degree of smoltification affected their downstream migration time and duration of stay in the estuary. Therefore, hatchery managers should consider having smolts fully developed and ready for release during the peak of the near-shore plankton blooms. Monitoring chlorophyll a levels and water temperature early in the spring could provide a forecast of the timing of these blooms, giving hatcheries time to adjust their release schedule. 相似文献
77.
78.
Christopher M Jones Daniel RH Graf David Bru Laurent Philippot Sara Hallin 《The ISME journal》2013,7(2):417-426
Nitrous oxide (N2O) is a major radiative forcing and stratospheric ozone-depleting gas emitted from terrestrial and aquatic ecosystems. It can be transformed to nitrogen gas (N2) by bacteria and archaea harboring the N2O reductase (N2OR), which is the only known N2O sink in the biosphere. Despite its crucial role in mitigating N2O emissions, knowledge of the N2OR in the environment remains limited. Here, we report a comprehensive phylogenetic analysis of the nosZ gene coding the N2OR in genomes retrieved from public databases. The resulting phylogeny revealed two distinct clades of nosZ, with one unaccounted for in studies investigating N2O-reducing communities. Examination of N2OR structural elements not considered in the phylogeny revealed that the two clades differ in their signal peptides, indicating differences in the translocation pathway of the N2OR across the membrane. Sequencing of environmental clones of the previously undetected nosZ lineage in various environments showed that it is widespread and diverse. Using quantitative PCR, we demonstrate that this clade was most often at least as abundant as the other, thereby more than doubling the known extent of the overall N2O-reducing community in the environment. Furthermore, we observed that the relative abundance of nosZ from either clade varied among habitat types and environmental conditions. Our results indicate a physiological dichotomy in the diversity of N2O-reducing microorganisms, which might be of importance for understanding the relationship between the diversity of N2O-reducing microorganisms and N2O reduction in different ecosystems. 相似文献
79.
80.
Binding site of the M-domain of human protein SRP54 determined by systematic site-directed mutagenesis of signal recognition particle RNA. 总被引:4,自引:1,他引:3 下载免费PDF全文
The interaction of protein SRP54M from the human signal recognition particle with SRP RNA was studied by systematic site-directed mutagenesis of the RNA molecule. Protein binding sites were identified by the analysis of mutations that removed individual SRP RNA helices or disrupted helical sections in the large SRP domain. The strongest effects on the binding activity of a purified polypeptide that corresponds to the methionine-rich domain of SRP54 (SRP54M) were caused by changes in helix 8 of the SRP RNA. Binding of protein SRP19 was diminished significantly by mutations in helix 6 and was stringently required for SRP54M to associate. Unexpectedly, mutant RNA molecules that resembled bacterial SRP RNAs were incapable of interaction with SRP54M, showing that protein SRP19 has an essential and direct role in the formation of the ternary complex with SRP54 and SRP RNA. Our findings provide an example for how, in eukaryotes, an RNA function has become protein dependent. 相似文献