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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.
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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34.
Wadden TA Neiberg RH Wing RR Clark JM Delahanty LM Hill JO Krakoff J Otto A Ryan DH Vitolins MZ;Look AHEAD Research Group 《Obesity (Silver Spring, Md.)》2011,19(10):1987-1998
This report provides a further analysis of the year 4 weight losses in the Look AHEAD (Action for Health in Diabetes) study and identifies factors associated with long-term success. A total of 5,145 overweight/obese men and women with type 2 diabetes were randomly assigned to an intensive lifestyle intervention (ILI) or a usual care group, referred to as Diabetes Support and Education (DSE). ILI participants were provided approximately weekly group or individual treatment in year 1; continued but less frequent contact was provided in years 2-4. DSE participants received three group educational sessions in all years. As reported previously, at year 4, ILI participants lost an average of 4.7% of initial weight, compared with 1.1% for DSE (P < 0.0001). More ILI than DSE participants lost ≥ 5% (46% vs. 25%, P < 0.0001) and ≥ 10% (23% vs. 10%, P < 0.0001) of initial weight. Within the ILI, achievement of both the 5% and 10% categorical weight losses at year 4 was strongly related to meeting these goals at year 1. A total of 887 participants in ILI lost ≥ 10% at year 1, of whom 374 (42.2%) achieved this loss at year 4. Participants who maintained the loss, compared with those who did not, attended more treatment sessions and reported more favorable physical activity and food intake at year 4. These results provide critical evidence that a comprehensive lifestyle intervention can induce clinically significant weight loss (i.e., ≥ 5%) in overweight/obese participants with type 2 diabetes and maintain this loss in more than 45% of patients at 4 years. 相似文献
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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
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Degradation of extracellular matrix by mouse trophoblast outgrowths: a model for implantation 总被引:7,自引:6,他引:1 下载免费PDF全文
During implantation the embryo attaches to the endometrial surface and trophoblast traverses the uterine epithelium, anchoring in the uterine connective tissue. To determine whether trophoblast can facilitate invasion of the uterus by degrading components of normal uterine extracellular matrix, mouse blastocysts were cultured on a radio-labeled extracellular matrix that contained glycoproteins, elastin, and collagen. The embryos attached to the matrix, and trophoblast spread over the surface. Starting on day 5 of culture there was a release of labeled peptides into the medium. The radioactive peptides released from the matrix by the embryos had molecular weights ranging from more than 25,000 to more than 200. By day 7 there were areas where individual trophoblast cells had separated from one another, revealing the underlying substratum that was cleared of matrix. When trophoblast cells were lysed with NH(4)OH on day 8, it was apparent that the area underneath the trophoblast outgrowth had been cleared of matrix. Scanning electron microscopy and time-lapse cinemicrography confirmed that the digestion of matrix was highly localized, taking place only underneath the trophoblast, with no evidence of digestion of the matrix beyond the periphery of the trophoblast outgrowth. The sharp boundaries of degredation observed may be due to localized proteinase secretion by trophoblast, to membrane proteinases on the surface of trophoblast, or to endocytosis. Digestion of the matrix was not dependent on plasminogen, thus ruling out a role for plasminogen activator. Digestion was not inhibited by a variety of hormones and inhibitors, including progesterone, 17β-estradiol, leupeptin, EDTA, colchicine, NH(4)Cl, or ε-aminocaproic acid. This system of culturing embryos on extracellular matrix may be useful in determining the processes that regulate trophoblast migration and invasion into the maternal tissues during implantation.0 相似文献
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Timothy?RH?RegnaultEmail author Hutton?V?Oddy Colin?Nancarrow Nadarajah?Sriskandarajah Rex?J?Scaramuzzi 《Reproductive biology and endocrinology : RB&E》2004,2(1):64
Background
Elevated non-esterified fatty acids (NEFA) concentrations in non-pregnant animals have been reported to decrease pancreatic responsiveness. As ovine gestation advances, maternal insulin concentrations fall and NEFA concentrations increase. Experiments were designed to examine if the pregnancy-associated rise in NEFA concentration is associated with a reduced pancreatic sensitivity to glucose in vivo. We investigated the possible relationship of NEFA concentrations in regulating maternal insulin concentrations during ovine pregnancy at three physiological states, non-pregnant, non-lactating (NPNL), 105 and 135 days gestational age (dGA, term 147+/- 3 days). 相似文献38.
Neiberg RH Wing RR Bray GA Reboussin DM Rickman AD Johnson KC Kitabchi AE Faulconbridge LF Kitzman DW Espeland MA 《Obesity (Silver Spring, Md.)》2012,20(10):2048-2056
This article provides an assessment of the associations that weight-loss patterns during the first year of an intensive lifestyle intervention have with 4-year maintenance and health outcomes. Two components described patterns of weight change during the first year of intervention: one reflected the typical pattern of weight loss over the 12 months, but distinguished those who lost larger amounts across the monthly intervals from those who lost less. The second component reflected the weight change trajectory, and distinguished a pattern of initial weight loss followed by regain vs. a more sustained pattern of weight loss. Two thousand four hundred and thirty eight individuals aged 45-76 years with type 2 diabetes mellitus, who enrolled in the weight-loss intervention of a randomized clinical trial, were assigned scores according to how their weight losses reflected these patterns. Relationships these scores had with weight losses and health outcomes (glycosolated hemoglobin-hemoglobin A1c (HbA1c); systolic blood pressure, high-density lipoprotein (HDL)-cholesterol, and triglycerides) over 4 years were described. When compared to those with lower scores on the two components, both individuals who had larger month-to-month weight losses in year 1 and whose weight loss was more sustained during the first year had better maintenance of weight loss over 4 years, independent of characteristics traditionally linked to weight loss success (P < 0.001). While relationships with year 4 weight loss were stronger, the pattern of larger monthly weight loss during year 1 was also independently predictive of year 4 levels of HbA1c, HDL-cholesterol, and systolic blood pressure. 相似文献
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