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981.
Background
Insertions and deletions (indels) are an important evolutionary force, making the evolutionary process more efficient and flexible by copying and removing genomic fragments of various lengths instead of rediscovering them by point mutations. As a mutational process, indels are known to be more active in specific sequences (like micro-satellites) but not much is known about the more general and mechanistic effect of sequence context on the insertion and deletion susceptibility of genomic loci. 相似文献982.
A survey of blood selenium (Se) concentrations in Norwegian Red heifers and dry period cows was conducted to reveal possible
association to management, feeding, health and fertility. Selenium contents were determined in 254 herd blood samples consisting
of pooled samples from individual non-lactating animals from herds in 5 counties. The Se concentrations showed a normal distribution
with mean 0.09 μg Se/g blood, with a standard deviation (SD) of 0.05, and ranged from 0.02 to 0.23 μg/g, with 50 % of the
samples being between 0.06 and 0.11 μg/g. The herds with Se concentrations below 0.06 μg/g were smaller (21.4 ± 8.7 cow-years)
than those with Se levels above 0.11 μg/g (27.5 ± 14.1 cow-years) (P < 0.01), but there were no differences in milk yield, incidence of replacement, proportion of animal culling, amount of concentrate
or grass silage as percentage of energy consumption between the groups. Treatment registration records showed a tendency that
more animals in the low Se herds were treated for all the diseases included in this investigation (64.8 animals per 100 cow-years)
than those in the high Se herds (57.5 per 100 cow-years), while no such differences were revealed for individual disorders.
There was, however, a significant difference in bulk milk somatic cell counts (BMSCC) between low and high Se herds, their
values being 137 000 and 155 000 cells/ml, respectively. This difference was significantly influenced by herd size. Furthermore,
a total of 4 916 lactations were analyzed from individual health and fertility recordings, including 2 934 first lactations
and 1 982 later lactations. The present study revealed a reduced incidence of disease treatment with increased Se concentrations
from 0.02 to 0.23 μg Se/g blood. In this regard, there seemed to be an optimum of 0.10 to 0.15 μg Se/g for all types of mastitis
treatments summarized, and for treatment of retained placenta. Thus, herd Se concentrations below and above these values was
connected with increased probability for sum mastitis and retained placenta, reflecting the effect of the quadratic term of
Se. The cow (composite) milk somatic cell count (SCC) was lower in lactations from low Se herds than in high Se herds with
a marked SCC increase in the Se concentration interval from 0.11–0.13 μg/g blood. In conclusion, heifers and dry period cows
in Norway are low in blood Se content and there seems to be a positive association between increased blood Se concentration
pre partum and decreased incidence of mastitis, ovarian cysts and anoestrus/silent oestrus post partum. 相似文献
983.
Abbas F Morellet N Hewison AJ Merlet J Cargnelutti B Lourtet B Angibault JM Daufresne T Aulagnier S Verheyden H 《Oecologia》2011,167(2):401-411
Forest fragmentation may benefit generalist herbivores by increasing access to various substitutable food resources, with
potential consequences for their population dynamics. We studied a European roe deer (Capreolus capreolus) population living in an agricultural mosaic of forest, woodlots, meadows and cultivated crops. We tested whether diet composition
and quality varied spatially across the landscape using botanical analyses of rumen contents and chemical analyses of the
plants consumed in relation to landscape metrics. In summer and non-mast winters, roe deer ate more cultivated seeds and less
native forest browse with increasing availability of crops in the local landscape. This spatial variation resulted in contrasting
diet quality, with more cell content and lower lignin and hemicellulose content (high quality) for individuals living in more
open habitats. The pattern was less marked in the other seasons when diet composition, but not diet quality, was only weakly
related to landscape structure. In mast autumns and winters, the consumption of acorns across the entire landscape resulted
in a low level of differentiation in diet composition and quality. Our results reflect the ability of generalist species,
such as roe deer, to adapt to the fragmentation of their forest habitat by exhibiting a plastic feeding behavior, enabling
them to use supplementary resources available in the agricultural matrix. This flexibility confers nutritional advantages
to individuals with access to cultivated fields when their native food resources are depleted or decline in quality (e.g.
during non-mast years) and may explain local heterogeneities in individual phenotypic quality. 相似文献
984.
Nakashima A Maruki Y Imamura Y Kondo C Kawamata T Kawanishi I Takata H Matsuura A Lee KS Kikkawa U Ohsumi Y Yonezawa K Kamada Y 《PloS one》2008,3(5):e2223
The target of rapamycin (Tor) protein plays central roles in cell growth. Rapamycin inhibits cell growth and promotes cell cycle arrest at G1 (G0). However, little is known about whether Tor is involved in other stages of the cell division cycle. Here we report that the rapamycin-sensitive Tor complex 1 (TORC1) is involved in G2/M transition in S. cerevisiae. Strains carrying a temperature-sensitive allele of KOG1 (kog1-105) encoding an essential component of TORC1, as well as yeast cell treated with rapamycin show mitotic delay with prolonged G2. Overexpression of Cdc5, the yeast polo-like kinase, rescues the growth defect of kog1-105, and in turn, Cdc5 activity is attenuated in kog1-105 cells. The TORC1-Type2A phosphatase pathway mediates nucleocytoplasmic transport of Cdc5, which is prerequisite for its proper localization and function. The C-terminal polo-box domain of Cdc5 has an inhibitory role in nuclear translocation. Taken together, our results indicate a novel function of Tor in the regulation of cell cycle and proliferation. 相似文献
985.
Mi Yoon Chung Jordi López-Pujol Sungwon Son Gang Uk Suh Tomohisa Yukawa Myong Gi Chung 《The Botanical review》2018,84(1):1-25
To provide basic information for orchid conservation, we surveyed the plant allozyme literature to summarize genetic diversity and structure data for (i) rare orchids native to the Korean Peninsula, and (ii) their congeners irrespective of being common and rare or Korean or not. A total of 68 taxa (32 taxa in Korea and 37 outside Korea; Goodyera repens being included in both datasets) were considered in this study. Overall, rare Korean orchid species had significantly lower levels of genetic diversity than their common congeners and common orchids in general at both population and species levels. However, mean values of G ST (or F ST) for rare and common orchids (Korean or not) did not differ significantly from each other. We found patterns of both low and high genetic diversity in rare Korean orchids. Many rare orchids harbored a complete lack of allozyme variation or extremely low within-population variation, perhaps due to rarity associated with random genetic drift and/or, for the case of warm-temperate orchids, to founder effects during post-glacial re-colonization. In contrast, high levels of genetic variation were found for a few orchids that have become recently rare (due to over-collection during the past several decades), probably because there have not been sufficient generations for the initial diversity to be substantially eroded. In addition, several orchids occurring in the main mountain system of the Korean Peninsula (the Baekdudaegan), that served as a glacial refugium, maintained moderate to high levels of within-population genetic diversity. Based on our genetic data, conservation priority should be given to rare orchid species. Particularly, urgent measures should be implemented on Jeju Island, a popular vacation spot, because it also a hotspot for threatened orchids with low levels of genetic diversity. 相似文献
986.
Nishanta Rajakaruna 《The Botanical review》2018,84(1):39-78
Plants adapted to special soil types are ideal for investigating evolutionary processes, including maintenance of intraspecific variation, adaptation, reproductive isolation, ecotypic differentiation, and the tempo and mode of speciation. Common garden and reciprocal transplant approaches show that both local adaptation and phenotypic plasticity contribute to edaphic (soil-related) specialization. Edaphic specialists evolve rapidly and repeatedly in some lineages, offering opportunities to investigate parallel evolution, a process less commonly documented in plants than in animals. Adaptations to soil features are often under the control of major genes and they frequently have direct or indirect effects on genes that contribute to reproductive isolation. Both reduced competitiveness and greater susceptibility to herbivory have been documented among some edaphic specialists when grown in ‘normal’ soils, suggesting that a high physiological cost of tolerance may result in strong divergent selection across soil boundaries. Interactions with microbes, herbivores, and pollinators influence soil specialization either by directly enhancing tolerance to extremes in soil conditions or by reducing gene flow between divergent populations. Climate change may further restrict the distribution of edaphic specialists due to increased competition from other taxa or, expand their ranges, if preadaptations to drought or other abiotic stressors render them more competitive under a novel climate. 相似文献
987.
Little information exists on mixed-species groups between primates and other mammals in Neotropical forests. In this paper, we describe three such associations observed during an extensive large-vertebrate survey in central Amazonia, Brazil. Mixed-species groups between a primate species and another mammal were observed on seven occasions between squirrel monkeys (Saimiri cf. ustus) and either South American coatis (Nasua nasua) or tayras (Eira barbara) and between brown capuchins (Cebus apella) and coatis. All associations were restricted to floodplain forest during its dry stage. We suggest that the associations involving the coatis are connected to foraging and vigilance but may be induced by a common alternative food resource at a time of food shortage. 相似文献
988.
Zenghong Ma Wei Cai Lei Wang Chenglin Du Weiwei Luo Linyu Niu Shuqing Xue Mengxin Ren Xinzheng Zhang Jingjun Xu 《Plasmonics (Norwell, Mass.)》2016,11(6):1481-1486
Magnetic hot spots, which implies confinements and enhancements of magnetic fields, are demonstrated in graphene junctions (GJs) in the mid-infrared range. The appearance of magnetic hot spots in GJs comes from the conduction currents in the junction. In further, the extinction resonance peaks suffer blue shift, along with the increases in the magnetic fields inside junction area, when the junction width reduces. In opposite to the circumstances for electric field enhancements, neither magnetic field enhancements nor resonance frequency of GJs is perturbed by the intrinsic nonlocal electronic response of graphene. Such nonlocality immunized magnetic enhancement could be explained by the polarization dependent property of nonlocal effect. 相似文献
989.
Pascal Badiou Rhonda McDougal Dan Pennock Bob Clark 《Wetlands Ecology and Management》2011,19(3):237-256
North American prairie pothole wetlands are known to be important carbon stores. As a result there is interest in using wetland
restoration and conservation programs to mitigate the effects of increasing greenhouse gas concentration in the atmosphere.
However, the same conditions which cause these systems to accumulate organic carbon also produce the conditions under which
methanogenesis can occur. As a result prairie pothole wetlands are potential hotspots for methane emissions. We examined change
in soil organic carbon density as well as emissions of methane and nitrous oxide in newly restored, long-term restored, and
reference wetlands across the Canadian prairies to determine the net GHG mitigation potential associated with wetland restoration.
Our results indicate that methane emissions from seasonal, semi-permanent, and permanent prairie pothole wetlands are quite
high while nitrous oxide emissions from these sites are fairly low. Increases in soil organic carbon between newly restored
and long-term restored wetlands supports the conclusion that restored wetlands sequester organic carbon. Assuming a sequestration
duration of 33 years and a return to historical SOC densities we estimate a mean annual sequestration rate for restored wetlands
of 2.7 Mg C ha−1year−1 or 9.9 Mg CO2 eq. ha−1 year−1. Even after accounting for increased CH4 emissions associated with restoration our research indicates that wetland restoration would sequester approximately 3.25 Mg
CO2 eq. ha−1year−1. This research indicates that widescale restoration of seasonal, semi-permanent, and permanent wetlands in the Canadian prairies
could help mitigate GHG emissions in the near term until a more viable long-term solution to increasing atmospheric concentrations
of GHGs can be found. 相似文献
990.
Protein pattern has played an important role in biosensors, bioMEMS, tissue engineering, fundamental studies of cell biology, and basic proteomics research. Here, we developed a straightforward and effective protein patterning technique using macroporous poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogel micropatterns as a three-dimensional (3D) template for protein immobilization. Micropatterns of macroporous hydrogels with inverse opal structures were prepared on poly(ethylene glycol) (PEG)-coated silicon substrates by combining a colloidal crystal templating method with photopatterning. The resultant inverse opal hydrogel (IOH) micropatterns were modified with 3-aminopropyltriethoxysilane using the hydroxyl groups in PHEMA for the covalent immobilization of proteins. Proteins were selectively immobilized only on the hydrogel micropatterns, while the PEG regions served as an effective barrier to protein adsorption. Because of their highly ordered and interconnected 3D macroporous structures and large internal surface areas, protein loading in the IOH micropattern was about six times greater than that on a non-porous hydrogel micropattern, which consequently improved the protein activity. The porosity of the hydrogel micropatterns could be controlled using different sizes of colloidal nanoparticles, and using smaller nanoparticles produced hydrogel micropatterns with higher protein loading capacities and activities. To demonstrate the potential use of IOH micropatterns in biosensor systems, biotin was micropatterned on the hydrogels and the specific binding of streptavidin was successfully assayed using IOH micropatterns with better fluorescence signals and sensitivity than that of the corresponding non-porous hydrogel micropatterns. 相似文献