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1.
We have analyzed a total of 12 different global and local multiple
protein-sequence alignment methods. The purpose of this study is to
evaluate each method's ability to correctly identify the ordered series of
motifs found among all members of a given protein family. Four
phylogenetically distributed sets of sequences from the hemoglobin, kinase,
aspartic acid protease, and ribonuclease H protein families were used to
test the methods. The performance of all 12 methods was affected by (1) the
number of sequences in the test sets, (2) the degree of similarity among
the sequences, and (3) the number of indels required to produce a multiple
alignment. Global methods generally performed better than local methods in
the detection of motif patterns.
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2.
Reactive oxygen species alter contractile properties of pulmonary arterial smooth muscle 总被引:2,自引:0,他引:2
R A Rhoades C S Packer D A Roepke N Jin R A Meiss 《Canadian journal of physiology and pharmacology》1990,68(12):1581-1589
Reactive oxygen species alter pulmonary arterial vascular tone and cause changes in pulmonary vascular resistance. The objective of this investigation was to determine direct effects of oxygen radicals on the contractile properties of pulmonary arterial smooth muscle. Isolated pulmonary arterial rings from Sprague-Dawley rats were placed in tissue baths containing Earle's balanced salt solution (gassed with 95% O2 - 5% CO2, 37 degrees C, pH 7.4). Vessels were contracted with 80 mM KCl to establish maximum active force production (Po). All other responses were normalized as percentages of Po for comparative purposes. Reactive oxygen metabolites were generated enzymatically with either the xanthine oxidase (XO) reaction or the glucose oxidase (GO) reaction, or hydrogen peroxide (H2O2) was added directly to the muscle bath. Exposure to XO, GO, or to H2O2 resulted in a contractile response that was sustained during the 30-min exposure period. The muscle fully relaxed following removal of the reactive oxygen species. Resting tension remained unchanged throughout the experimental period, suggesting no functional change in membrane potential. The contractile response was dose dependent and was not prevented by either cyclooxygenase or lipoxygenase inhibition, or by removal of the endothelium. Pretreatment of vessels with superoxide dismutase (SOD) partially blocked the XO-induced contraction, while mannitol or deferoxamine had no effect on the response to XO. However, pretreatment with catalase (CAT) completely blocked the XO-induced contraction. These data suggest that superoxide ions and hydrogen peroxide are the major causative agents. Following O2-radical exposure, vessels showed a decrease in contractile responsiveness to 80 mM KCl (recovery response), suggesting damage to the smooth muscle cells.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
3.
The African Black Oystercatcher Haematopus moquini is a charismatic, southern African near-endemic, wader species, that is often seen as a flagship species for coastal bird conservation, as it was recently down-listed regionally to Least Concern on the IUCN Red List of Threatened Species. To celebrate this rare conservation success story, BirdLife South Africa named it the 2018 Bird of the Year and ran a year-long programme in collaboration with the Nature’s Valley Trust highlighting aspects of the species’ biology, current threats, and conservation success. We used data collected by the Southern African Bird Atlas Project (SABAP1 and SABAP2) to examine changes in the species’ range and relative abundance, both in the records between the two projects, as well as trends within the SABAP2 sampling period (2008–2017). This case study enabled us to assess whether such metrics can accurately reflect abundance and distributional changes in a species. We found increases in the reported range and the reporting rates between the two Atlas projects, and that the SABAP2 reporting rate was stable. Regionally, across four coastal categories, the reporting rate was lowest in KwaZulu-Natal, though this region also showed an increase in the probability of reporting during the SABAP2 period. While corroborating the recent change in the species’ conservation status, we also provide good evidence that the long-term SABAP data can be used successfully to assess population trends and range changes over time. 相似文献
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5.
Out of Africa and back again: nested cladistic analysis of human Y chromosome variation 总被引:18,自引:3,他引:15
Hammer MF; Karafet T; Rasanayagam A; Wood ET; Altheide TK; Jenkins T; Griffiths RC; Templeton AR; Zegura SL 《Molecular biology and evolution》1998,15(4):427-441
We surveyed nine diallelic polymorphic sites on the Y chromosomes of 1,544
individuals from Africa, Asia, Europe, Oceania, and the New World.
Phylogenetic analyses of these nine sites resulted in a tree for 10
distinct Y haplotypes with a coalescence time of approximately 150,000
years. The 10 haplotypes were unevenly distributed among human populations:
5 were restricted to a particular continent, 2 were shared between Africa
and Europe, 1 was present only in the Old World, and 2 were found in all
geographic regions surveyed. The ancestral haplotype was limited to African
populations. Random permutation procedures revealed statistically
significant patterns of geographical structuring of this paternal genetic
variation. The results of a nested cladistic analysis indicated that these
geographical associations arose through a combination of processes,
including restricted, recurrent gene flow (isolation by distance) and range
expansions. We inferred that one of the oldest events in the nested
cladistic analysis was a range expansion out of Africa which resulted in
the complete replacement of Y chromosomes throughout the Old World, a
finding consistent with many versions of the Out of Africa Replacement
Model. A second and more recent range expansion brought Asian Y chromosomes
back to Africa without replacing the indigenous African male gene pool.
Thus, the previously observed high levels of Y chromosomal genetic
diversity in Africa may be due in part to bidirectional population
movements. Finally, a comparison of our results with those from nested
cladistic analyses of human mtDNA and beta-globin data revealed different
patterns of inferences for males and females concerning the relative roles
of population history (range expansions) and population structure
(recurrent gene flow), thereby adding a new sex-specific component to
models of human evolution.
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6.
Little is known about the effect of exercise training on the expression of adiponectin receptor genes in peripheral blood mononuclear cells (PBMCs). In this study, we investigated the effects of aerobic training on the expression of AdipoR1 and AidpoR2 mRNAs in PBMCs, whole body insulin sensitivity, and circulating adiponectins in men. Thirty young men were randomly assigned to either a control (n=15) or an exercise (n=15) group. Subjects assigned to the exercise group underwent a 12-week jogging and/or running programme on a motor-driven treadmill at an intensity of 60%-75% of the age-based maximum heart rate with duration of 40 minutes per session and a frequency of 5 days per week. Two-way mixed ANOVA with repeated measures was used to test any significant time-by-group interaction effects for the measured variables at p=0.05. We found significant time-by-group interaction effects for waist circumference (p=0.001), VO2max (p<0.001), fasting insulin (p=0.016), homeostasis model assessment for insulin resistance (HOMA-IR) (p=0.010), area under the curve (AUC) for insulin response during the 75-g oral glucose tolerance test (p=0.002), high-molecular weight (HMW) adiponectin (p=0.016), and the PBMC mRNA levels of AdipoR1 (p<0.001) and AdipoR2 (p=0.001). The exercise group had significantly increased mRNA levels of AdipoR1 and AdipoR2 in PBMCs, along with increased whole body insulin sensitivity and HMW adiponectin, decreased waist circumference, and increased VO2max compared with the control group. In summary, the current findings suggest that exercise training modulates the expression of AdipoR1 and AdipoR2 mRNAs in PBMCs, implying that manipulation of the expression of these genes could be a potential surrogate for lifestyle intervention-mediated improvements of whole body insulin sensitivity and glucose homeostasis. 相似文献
7.
Roepke TA Chang ES Cherr GN 《Journal of experimental zoology. Part A, Comparative experimental biology》2006,305(10):830-841
Endocrine disrupting compounds (EDCs) are known to affect reproduction and development in marine invertebrates. In previous work, we have shown that developing sea urchin embryos were sensitive to estradiol and estrogenic EDCs at environmentally relevant concentrations in a tamoxifen-sensitive manner (Roepke et al. 2005. Aquat Toxicol 71:155-173). In this study, we report the effects of maternal exposure to EDCs on embryo sensitivity and regulation of an orphan steroid receptor in sea urchin eggs. Maternal exposures were conducted by injecting female Strongylocentrotus purpuratus sea urchins initiating oogenesis with two concentrations of estradiol, octylphenol, tributyltin and o, p-DDD for 8 weeks with an induced spawning before and after the injection cycle. Developing embryos were less sensitive to estradiol following maternal exposure to estradiol, octylphenol and DDD. The steroidogenesis inhibitor, spironolactone, and the aromatase inhibitor, formestane, affected normal sea urchin development with EC50 values of 18 and 2 microM, respectively. Binding of estradiol was demonstrated in homogenates supernatants of sea urchin embryos by filtration centrifugation and column chromatography, but saturation was not reached until 4-6 hr and was highly variable. Analysis of eggs from pre- and post-injection spawns using real-time Q-PCR for the mRNA of an orphan steroid receptor, SpSHR2, shows that receptor mRNA increased in eggs with estradiol, octylphenol and tributyltin but decreased with DDD. RIA showed that estradiol may be present during gastrulation. In summary, maternal exposure to estradiol and EDCs alters embryo sensitivity and regulates the expression of an orphan steroid receptor in the egg. 相似文献
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Estelle Bockers Stefan Roepke Lars Michael Babette Renneberg Christine Knaevelsrud 《PloS one》2014,9(9)
Background
Previous research has identified a number of variables that constitute potential risk factors for victimization and revictimization. However, it remains unclear which factors are associated not only with childhood or adolescent victimization, but specifically with revictimization. The aim of this study was to determine whether risk recognition ability and other variables previously associated with revictimization are specifically able to differentiate individuals with childhood victimization only from revictimized individuals, and thus to predict revictimization.Methods
Participants were N = 85 women aged 21 to 64 years who were interpersonally victimized in childhood or adolescence only, interpersonally revictimized in another period of life, or not victimized. A logistic regression analysis was conducted to examine whether risk recognition ability, sensation seeking, self-efficacy, state dissociation, shame, guilt, assertiveness, and attachment anxiety predicted group membership.Results
The logistic regression analysis revealed risk recognition ability, attachment anxiety, state dissociation, and self-efficacy as significant predictors of revictimization. The final model accurately classified 82.4% of revictimized, 59.1% of victimized and 93.1% of non-victimized women. The overall classification rate was 80%.Conclusions
This study suggests that risk recognition ability, attachment anxiety, self-efficacy, and state dissociation play a key role in revictimization. Increased risk recognition ability after an interpersonal trauma may act as a protective factor against repeated victimization that revictimized individuals may lack. A lack of increased risk recognition ability in combination with higher attachment anxiety, lower self-efficacy, and higher state dissociation may increase the risk of revictimization. 相似文献10.
Young-Bin Chen Ying-Wei Lan Tsai-Hsien Hung Lih-Geeng Chen Kong-Bung Choo Winston TK Cheng Hsuan-Shu Lee Kowit-Yu Chong 《Cell stress & chaperones》2015,20(4):643-652
Several studies of stem cell-based gene therapy have indicated that long-lasting regeneration following vessel ischemia may be stimulated through VEGFA gene therapy and/or MSC transplantation for reduction of ischemic injury in limb ischemia and heart failure. The therapeutic potential of MSC transplantation can be further improved by genetically modifying MSCs with genes which enhance angiogenesis following ischemic injury. In the present study, we aimed to develop an approach in MSC-based therapy for repair and mitigation of ischemic injury and regeneration of damaged tissues in ischemic disease. HSP70 promoter-driven VEGFA expression was induced by resveratrol (RSV) in MSCs, and in combination with known RSV biological functions, the protective effects of our approach were investigated by using ex vivo aortic ring coculture system and a 3D scaffolds in vivo model. Results of this investigation demonstrated that HSP promoter-driven VEGFA expression in MSC increased approximately 2-fold over the background VEGFA levels upon HSP70 promoter induction by RSV. Exposure of HUVEC cells to medium containing MSC in which VEGFA had been induced by cis-RSV enhanced tube formation in the treated HUVEC cells. RSV-treated MSC cells differentiated into endothelial-like phenotypes, exhibiting markedly elevated expression of endothelial cell markers. These MSCs also induced aortic ring sprouting, characteristic of neovascular formation from pre-existing vessels, and additionally promoted neovascularization at the MSC transplantation site in a mouse model. These observations support a hypothesis that VEGFA expression induced by cis-RSV acting on the HSP70 promoter in transplanted MSC augments the angiogenic effects of stem cell gene therapy. The use of an inducible system also vastly reduces possible clinical risks associated with constitutive VEGFA expression. 相似文献