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排序方式: 共有973条查询结果,搜索用时 31 毫秒
81.
Notch signaling is essential for ventricular chamber development 总被引:1,自引:0,他引:1
Grego-Bessa J Luna-Zurita L del Monte G Bolós V Melgar P Arandilla A Garratt AN Zang H Mukouyama YS Chen H Shou W Ballestar E Esteller M Rojas A Pérez-Pomares JM de la Pompa JL 《Developmental cell》2007,12(3):415-429
Ventricular chamber morphogenesis, first manifested by trabeculae formation, is crucial for cardiac function and embryonic viability and depends on cellular interactions between the endocardium and myocardium. We show that ventricular Notch1 activity is highest at presumptive trabecular endocardium. RBPJk and Notch1 mutants show impaired trabeculation and marker expression, attenuated EphrinB2, NRG1, and BMP10 expression and signaling, and decreased myocardial proliferation. Functional and molecular analyses show that Notch inhibition prevents EphrinB2 expression, and that EphrinB2 is a direct Notch target acting upstream of NRG1 in the ventricles. However, BMP10 levels are found to be independent of both EphrinB2 and NRG1 during trabeculation. Accordingly, exogenous BMP10 rescues the myocardial proliferative defect of in vitro-cultured RBPJk mutants, while exogenous NRG1 rescues differentiation in parallel. We suggest that during trabeculation Notch independently regulates cardiomyocyte proliferation and differentiation, two exquisitely balanced processes whose perturbation may result in congenital heart disease. 相似文献
82.
Biotechnology Letters - Determine the effect of secondary cell wall (SCW) thickness and microcrystalline cellulose content (MCC) on mature fiber strength (FS) and reveal through comparative... 相似文献
83.
84.
Changes in Patterns of Species Co‐occurrence across Two Tropical Cloud Forests Differing in Soil Nutrients and Air Temperature 下载免费PDF全文
Wenxing Long Menghui Xiong Runguo Zang Brandon S. Schamp Xiaobo Yang Yi Ding Yunfeng Huang Yangzhou Xiang 《Biotropica》2015,47(4):416-423
Patterns of co‐occurrence of species are increasingly used to examine the contribution of biotic interactions to community assembly. We assessed patterns of co‐occurrence at four scales, in two types of tropical cloud forests in Hainan Island, China (tropical montane evergreen forests, TMEF and tropical dwarf forests, TDF) that varied significantly in soil nutrients and temperature. We tested if the patterns of co‐occurrence changed when we sorted species into classes by abundance and diameter at breast height (dbh). Co‐occurrence differed by forest type and with plot size, with significant species aggregation observed across larger plots in TDF and patterns of species segregation observed in smaller plots in TMEF. Analyses of differential abundance and dbh classes also showed that smaller plots in TMEF tend to have negative co‐occurrence patterns, but larger plots in TDF tend to show patterns of aggregation, suggesting competitive and facilitative interactions. This underscores the scale‐dependence of the processes contributing to community assembly. Furthermore, it is consistent with predictions of the stress gradient hypothesis that facilitation will be most important in biological systems subject to abiotic stress, while competition will be more important in less abiotically stressful habitats. Our results clearly demonstrate that these two types of tropical cloud forest exhibit different co‐occurrence patterns, and that these patterns are scale‐dependent, though independent of plant abundance and size class. 相似文献
85.
Acetylcholine Inhibits Tumor Necrosis Factor α Activated Endoplasmic Reticulum Apoptotic Pathway via EGFR‐PI3K Signaling in Cardiomyocytes 下载免费PDF全文
86.
Liguo Feng Han Ding Jia Wang Meng Wang Wei Xia Shu Zang Lixia Sheng 《Saudi Journal of Biological Sciences》2015,22(4):417-423
Salt stress is one important factor influencing the growth and development of plants, and salt tolerance of plants is a result of combined action of multiple genes and mechanisms. Rosa rugosa is not only an important ornamental plant, but also the natural aromatic plant of high value. Wild R. rugosa which is naturally distributed on the coast and islands of China has a good salt tolerance due to the special living environment. Here, the vacuolar Na+/H+ reverse transporter gene (NHX1) and the vacuolar H+-ATPase subunit C gene (VHA-c) closely related to plant salt tolerance were isolated from wild R. rugosa, and the expression patterns in R. rugosa leaves of the two genes under NaCl stress were determined by real-time quantitative fluorescence PCR. The results showed that the RrNHX1 protein is a constitutive Na+/H+ reverse transporter, the expression of the RrNHX1 gene first increased and then decreased with the increasing salt concentration, and had a time-controlled effect. The RrVHA-c gene is suggestive of the housekeeping feature, its expression pattern showed a similar variation trend with the RrNHX1 gene under the stress of different concentrations of NaCl, and its temporal expression level under 200 mM NaCl stress presented bimodal change. These findings indicated that RrNHX1 and RrVHA-c genes are closely associated with the salt tolerance trait of wild R. rugosa. 相似文献
87.
88.
Xiaoru Long Simin Li Jun Xie Wei Li Na Zang Luo Ren Yu Deng Xiaohong Xie Lijia Wang Zhou Fu Enmei Liu 《Respiratory research》2015,16(1)
Background
Respiratory syncytial virus (RSV) is one of the most frequently observed pathogens during infancy and childhood. However, the corresponding pathogenesis has not been determined to date. We previously demonstrated that IFN-γ plays an important role in RSV pathogenesis, and SARM-TRIF-signaling pathway could regulate the production of IFN-γ. This study is to investigate whether T cells or innate immune cells are the predominant producers of IFN-γ, and further to explore other culprits in addition to IFN-γ in the condition of RSV infection.Methods
Normal BALB/c mice and nude mice deficient in T cells were infected intranasally with RSV. Leukocytes in bronchoalveolar lavage fluid were counted, lung histopathology was examined, and airway hyperresponsiveness (AHR) was measured by whole-body plethysmography. IFN-γ and MMP-12 were detected by ELISA. MMP408, a selective MMP-12 inhibitor, was given intragastrically. Resveratrol, IFN-γ neutralizing antibody and recombinant murine IFN-γ were administered intraperitoneally. SARM and TRIF protein were semi-quantified by Western blot. siRNA was used to knock-down SARM expression.Results
RSV induced significant airway inflammation and AHR in both mice; IFN-γ was significantly increased in BALB/c mice but not in nude mice. MMP-12 was dramatically increased in both mice but earlier in nude mice. When MMP-12 was inhibited by MMP408, RSV-induced respiratory symptoms were alleviated. SARM was significantly suppressed while TRIF was significantly enhanced in both mice strains. Following resveratrol administration in nude mice, 1) SARM inhibition was prevented, 2) TRIF and MMP-12 were correspondingly down-regulated and 3) airway disorders were subsequently alleviated. Moreover, when SARM was efficiently knocked down using siRNA, TRIF and MMP-12 were markedly enhanced, and the anti-RSV effects of resveratrol were remarkably abrogated. MMP-12 was significantly increased in the IFN-γ neutralizing antibody-treated BALB/c mice but reduced in the recombinant murine IFN-γ-treated nude mice.Conclusions
MMP-12 can result in at least part of the airway inflammation and AHR independent of IFN-γ. And SARM-TRIF- signaling pathway is involved in regulating the overproduction of MMP-12. To the best of our knowledge, this study is the first that has examined the effects of SARM on MMP-12 and further highlights the potential to target SARM-TRIF-MMP-12 cascades to treat RSV infection.Electronic supplementary material
The online version of this article (doi:10.1186/s12931-015-0176-8) contains supplementary material, which is available to authorized users. 相似文献89.
Petia Simeonova Nikolova Christian Zang Hans Pretzsch 《Trees - Structure and Function》2011,25(5):859-872
We show the potential of a new method combining tree-ring analyses on stems and on coarse roots of individual trees in order
to advance the understanding of growth dynamics in forest trees. To this end, we studied the root–shoot allometry of trees
and its dependence on site conditions. Along a gradient in water supply in Southern Germany from dry to moist sites we selected
43 Norway spruce trees (Picea abies [L.] H. Karst.) aged 65–100 years. Increment cores were taken from stem and main roots revealing aboveground and belowground
growth course over the last 34 years. Annual growth rates in roots and stems and their allometric relationships were applied
as surrogate variables for tree resource allocation to aboveground and belowground organs. The mean sensitivities of both
stem and root chronologies were found to be site-specific, and increased from the moist through the dry sites. No temporal
offset between aboveground and belowground growth reactions to climate conditions was found in Norway spruce at any of the
sites. These results suggest that the root–shoot allometry depends on the specific site conditions only at the driest site,
following the optimal biomass partitioning theory (the more restricted the water supply, the more organic matter allocation
into the belowground organs). 相似文献
90.
Zong S Wang Z Luo Y Zang J Wen J 《Zeitschrift für Naturforschung. C, Journal of biosciences》2011,66(11-12):621-626
We determined the mechanisms underlying host selection by adults of the seabuckthorn carpenterworm, Holcocerus hippophaecolus Hua, Chou, Fang et Chen. Four sea buckthorn (Hippophae rhamnoides L.) subspecies (varieties) with different degrees of resistance to H. hippophaecolus were chosen for artificial insect infection in cages. The results showed that olfactory and visual cues are very important for the selection of host plants by H. hippophaecolus, but that olfactory stimuli play a more vital role in this process. The relative abundance of branches and leaves had no effect on the likelihood that adults landed on plants from four subspecies (varieties), but did influence landing rates within the same subspecies (varieties). When considering only the most resistant sea buckthorn subspecies (varieties), the presence of luxuriant branches and leaves led to lower landing rates. These results provide a theoretical basis for the understanding of H. hippophaecolus damage to sea buckthorn and the means to implement effective measures of control. 相似文献