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排序方式: 共有1832条查询结果,搜索用时 15 毫秒
131.
Ignacio Fernández Jorge M.O. Fernandes Vânia P. Roberto Martina Kopp Catarina Oliveira Marta F. Riesco Jorge Dias Cymon J. Cox M. Leonor Cancela Elsa Cabrita Paulo Gavaia 《Biochimica et Biophysica Acta (BBA)/General Subjects》2019,1863(1):39-51
Background
Vitamin K (VK) is a fat-soluble vitamin known for its essential role in blood coagulation, but also on other biological processes (e.g. reproduction, brain and bone development) have been recently suggested. Nevertheless, the molecular mechanisms behind its particular function on reproduction are not yet fully understood.Methods
The potential role of VK on reproduction through nutritional supplementation in Senegalese sole (Solea senegalensis) was assessed by gonadal maturation and 11-ketosterone, testosterone and estriol plasma levels when fed with control or VK supplemented (1250?mg?kg?1 of VK1) diets along a six month trial. At the end, sperm production and quality (viability and DNA fragmentation) were evaluated. Circulating small non-coding RNAs (sncRNAs) in blood plasma from males were also studied through RNA-Seq.Results
Fish fed with dietary VK supplementation had increased testosterone levels and lower sperm DNA fragmentation. SncRNAs from blood plasma were found differentially expressed when nutritional and sperm quality conditions were compared. PiR-675//676//4794//5462 and piR-74614 were found up-regulated in males fed with dietary VK supplementation. Let-7g, let-7e(18nt), let-7a-1, let-7a-3//7a-2//7a-1, let-7e(23nt) and piR-675//676//4794//5462 were found to be up-regulated and miR-146a and miR-146a-1//146a-2//146a-3 down-regulated when fish with low and high sperm DNA fragmentation were compared. Bioinformatic analyses of predicted mRNAs targeted by sncRNAs revealed the potential underlying pathways.Conclusions
VK supplementation improves fish gonad maturation and sperm quality, suggesting an unexpected and complex regulation of the nutritional status and reproductive performance through circulating sncRNAs.General significance
The use of circulating sncRNAs as reliable and less-invasive physiological biomarkers in fish nutrition and reproduction has been unveiled. 相似文献132.
The increased prevalence of type 2 diabetes mellitus (T2DM) and life expectancy of diabetic patients fosters the worldwide prevalence of retinopathy and nephropathy, two major microvascular complications that have been difficult to treat with contemporary glucose-lowering medications. The gut microbiota (GM) has become a lively field research in the last years; there is a growing recognition that altered intestinal microbiota composition and function can directly impact the phenomenon of ageing and age-related disorders. In fact, human GM, envisaged as a potential source of novel therapeutics, strongly modulates host immunity and metabolism. It is now clear that gut dysbiosis and their products (e.g. p-cresyl sulfate, trimethylamine?N?oxide) dictate a secretory associated senescence phenotype and chronic low-grade inflammation, features shared in the physiological process of ageing (“inflammaging”) as well as in T2DM (“metaflammation”) and in its microvascular complications. This review provides an in-depth look on the crosstalk between GM, host immunity and metabolism. Further, it characterizes human GM signatures of elderly and T2DM patients. Finally, a comprehensive scrutiny of recent molecular findings (e.g. epigenetic changes) underlying causal relationships between GM dysbiosis and diabetic retinopathy/nephropathy complications is pinpointed, with the ultimate goal to unravel potential pathophysiological mechanisms that may be explored, in a near future, as personalized disease-modifying therapeutic approaches. 相似文献
133.
Shanglun Xie Shanshan Han Zhen Qu Fei Liu Jingzhen Li Shanshan Yu James Reilly Jiayi Tu Xiliang Liu Zhaojing Lu Xuebin Hu Tinsae Assefa Yimer Yayun Qin Yuwen Huang Yuexia Lv Tao Jiang Xinhua Shu Zhaohui Tang Mugen Liu 《生物化学与生物物理学报:疾病的分子基础》2019,1865(6):1273-1283
Mutations in the photoreceptor cell-specific nuclear receptor gene Nr2e3 increased the number of S-cone photoreceptors in human and murine retinas and led to retinal degeneration that involved photoreceptor and non-photoreceptor cells. The mechanisms underlying these complex phenotypes remain unclear. In the hope of understanding the precise role of Nr2e3 in photoreceptor cell fate determination and differentiation, we generated a line of Nr2e3 knockout zebrafish using CRISPR technology. In these Nr2e3-null animals, rod precursors undergo terminal mitoses but fail to differentiate as rods. Rod-specific genes are not expressed and the outer segment (OS) fails to form. Formation and differentiation of cone photoreceptors is normal. Specifically, there is no increase in the number of UV-cone or S-cone photoreceptors. Laminated retinal structure is maintained. After normal development, L-/M-cones selectively degenerate, with progressive shortening of OS that starts at age 1 month. The amount of cone phototransduction proteins is concomitantly reduced, whereas UV- and S-cones have normal OS lengths even at age 10 months. In vitro studies show Nr2e3 synergizes with Crx and Nrl to enhance rhodopsin gene expression. Nr2e3 does not affect cone opsin expression. Our results extend the knowledge of Nr2e3's roles and have specific implications for the interpretation of the phenotypes observed in human and murine retinas. Furthermore, our model may offer new opportunities in finding treatments for enhanced S-cone syndrome (ESCS) and other retinal degenerative diseases. 相似文献
134.
135.
以Web of Science为数据源,简要概括生物信息学数据库研究的发展趋势。利用Cite Space可视化工具展现生物信息学数据库研究的知识基础和研究热点图谱,为开展生物信息学数据库领域相关的理论研究和实践活动提供借鉴,以便推动生物信息学数据库研究的发展。研究表明:1990年Altschul SF发表的"局部比对搜索工具——BLAST"是生物信息学数据库研究的重要知识来源文献;热点主题集中在序列库、基因组数据库、分类数据库、蛋白质数据库、数据库更新、集成系统等。 相似文献
136.
Habitat loss and fragmentation are serious threats to biodiversity conservation in the Atlantic Forest. A network of protected reserves is essential to the protection of native fauna and flora. However, internal and external factors may threaten the preservation of biota, thus population viability analyses (PVA) are important tools in reserve design and management planning. A PVA was carried out, using the computer package VORTEX, to assess the effectiveness of the reserve network of Rio de Janeiro State in Brazil in retaining viable populations of the endemic marsupial Micoureus travassosi. The PVA takes into account demographic, genetic and environmental stochastic events and catastrophes (fire). Rio de Janeiro state has 31 reserves, and 20 of those were considered to retain viable populations for 100 years, whereas eight were predicted to suffer from genetic decay, two from both genetic decay and demographic stochasticity, and one of them probably has an extinct population. The minimum area of suitable habitat needed to maintain a minimum viable population of M. travassosi is estimated at 3600ha. Sensitivity analysis was run for mortality, sex ratio, percentage of reproductive females, inbreeding depression and probability of catastrophes, and suggests that inbreeding depression is important in small population sizes, whereas the effects of catastrophes were significant only for large populations. Although the model indicates that some populations will suffer from demographic and/or genetic stochasticity, the reserve network of Rio de Janeiro state will likely keep M. travassosi's populations for the next 100 years. 相似文献
137.
Lavelle P Blouin M Boyer J Cadet P Laffray D Pham-Thi AT Reversat G Settle W Zuily Y 《Comptes rendus biologies》2004,327(7):629-638
The use of pesticides to control plant parasites and diseases has generated serious problems of public health and environmental quality, leading to the promotion of alternative Integrated Pest Management strategies that tend to rely more on natural processes and the active participation of farmers as observers and experimenters in their own fields. We present three case studies that point at different options provided by locally available populations of soil organisms, the maintenance of diverse populations of pests or increased resistance of plants to pest attacks by their interactions with earthworms and other useful soil organisms. These examples demonstrate the diversity of options offered by the non-planned agro-ecosystem diversity in pest control and the need to identify management options that maintain this biodiversity. 相似文献
138.
The pollen competition hypothesis predicts that when the number of pollen grains deposited onto stigmas exceeds the number of ovules, selection can operate in the time frame between deposition and fertilization. Moreover, because of the overlap in gene expression between the two phases of the life cycle, selection on microgametophytes may alter the resulting sporophytic generation. The extent to which pollen competition occurs in nature has been unclear, because tests of the predictions of the pollen competition hypothesis have used cultivars and/or artificial growth conditions and hand-pollination techniques. In this study we used a wild species, Cucurbita foetidissima, in its natural habitat (southern New Mexico) to determine the amount and timing of the arrival of pollen onto stigmas, the relationship between pollen deposition and seed number, and the effects of the intensity of pollen competition on progeny vigor. We found that ~900 pollen grains are necessary for full seed set and that a single visit by a pollinator results in the deposition of 653.0 ± 101.8 pollen grains. About 29% of the flowers receiving a single pollinator visit had 900 or more pollen grains on its stigma. Moreover, within 2 h of anthesis, >4000 pollen grains were deposited onto a typical stigma, indicating that multiple pollinator visits must have occurred. Fruits produced by multiple visits had greater seed numbers (206 vs. 147) than fruits produced by a single visit. Finally, the progeny produced by multiple pollinator visits were more vigorous than those produced by single visits with respect to five measures of vegetative growth (MANCOVA, Wilks' lambda = 0.96, F(6,370) = 2.54, P < 0.02. These data demonstrate that conditions for pollen competition exist in nature and support the prediction that pollen competition enhances offspring vigor. 相似文献
139.
140.
The 'system management approach' of biological weed control was applied in a small-scale field experiment with celeriac (root celery), intersown with an inbred line of the annual weed Senecio vulgaris L. The naturalized rust fungus Puccinia lagenophorae Cooke (Basidiomycetes: Uredinales), a common and widespread pathogen of S. vulgaris in Europe, was introduced into parts of the plots, and its impact on the competitive balance between the crop and weed in the presence and absence of an additional herbicide treatment was studied. Competition by S. vulgaris (at a realized density of only 50 plants/m2) during the first 10 weeks of growth was substantial, reducing the fresh weight of the celeriac bulbs by 28%. The epidemic spread of the rust fungus was relatively fast, and the time to infection was similar to that in full-area applications. Inoculation with the rust fungus strongly reduced crop losses due to competition with S. vulgaris . The fresh weight of the celeriac bulbs in plots with both S. vulgaris and the fungus was not statistically diVerent from the celeriac yield in plots without S. vulgaris . This eVect was mainly the result of the reduced biomass of S. vulgaris , and not reduced survival. Infected plants may, therefore, still contribute to soil cover and may help to suppress later germinating weed species. Older plant stages were found to be infected earlier than younger stages. No significant interactions were observed between the eVects of the fungal infection and a low-dose application of the herbicide chlorbromuron on weed performance. Basic studies necessary to develop the system management approach further are discussed. 相似文献