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Rick G. Kelsey Jerry W. Thomas Thomas J. Watson Fred Shafizadeh 《Biochemical Systematics and Ecology》1975,3(4):209-213
The sesquiterpene lactones and chromosome numbers for three chemical races of Artemisia tridentata ssp. vaseyana have been examined from four populations in western Montana. TLC analysis of the sesquiterpene lactones in the seeds and seed producing parents demonstrated that genetic exchange does occur between sympatric sesquiterpene lactone chemical races. However, other evidence suggests that introgression between these races is restricted to zones of sympatry. There appears to be no correlation between chromosome numbers and sesquiterpene lactone races. 相似文献
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Tim Toplak Elvis Pandzic Lingfeng Chen Miguel Vicente-Manzanares Alan?Rick Horwitz Paul?W. Wiseman 《Biophysical journal》2012,103(8):1672-1682
Two-color spatio-temporal image cross-correlation spectroscopy (STICCS) is a new, to our knowledge, image analysis method that calculates space-time autocorrelation and cross-correlation functions from fluorescence intensity fluctuations. STICCS generates cellular flow and diffusion maps that reveal interactions and cotransport of two distinct molecular species labeled with different fluorophores. Here we use computer simulations to map the capabilities and limitations of STICCS for measurements in complex heterogeneous environments containing micro- and macrostructures. We then use STICCS to analyze the co-flux of adhesion components in migrating cells imaged using total internal reflection fluorescence microscopy. The data reveal a robust, time-dependent co-fluxing of certain integrins and paxillin in adhesions in protrusions when they pause, and in adhesions that are sliding and disassembling, demonstrating that the molecules in these adhesions move as a complex. In these regions, both α6β1- or αLβ2-integrins, expressed in CHO.B2 cells, co-flux with paxillin; an analogous cotransport was seen for α6β1-integrin and α-actinin in U2OS. This contrasts with the behavior of the α5β1-integrin and paxillin, which do not co-flux. Our results clearly show that integrins can move in complexes with adhesion proteins in protrusions that are retracting. 相似文献
45.
Luise Ehlers Karen Bannert Sarah Rohde Peggy Berlin Johannes Reiner Mats Wiese Julia Doller Markus M. Lerch Ali A. Aghdassi Fatuma Meyer Luzia Valentini Ottavia Agrifoglio Cornelia C. Metges Georg Lamprecht Robert Jaster 《Journal of cellular and molecular medicine》2020,24(15):8304-8314
Muscle wasting represents a constant pathological feature of common chronic gastrointestinal diseases, including liver cirrhosis (LC), inflammatory bowel diseases (IBD), chronic pancreatitis (CP) and pancreatic cancer (PC), and is associated with increased morbidity and mortality. Recent clinical and experimental studies point to the existence of a gut‐skeletal muscle axis that is constituted by specific gut‐derived mediators which activate pro‐ and anti‐sarcopenic signalling pathways in skeletal muscle cells. A pathophysiological link between both organs is also provided by low‐grade systemic inflammation. Animal models of LC, IBD, CP and PC represent an important resource for mechanistic and preclinical studies on disease‐associated muscle wasting. They are also required to test and validate specific anti‐sarcopenic therapies prior to clinical application. In this article, we review frequently used rodent models of muscle wasting in the context of chronic gastrointestinal diseases, survey their specific advantages and limitations and discuss possibilities for further research activities in the field. We conclude that animal models of LC‐, IBD‐ and PC‐associated sarcopenia are an essential supplement to clinical studies because they may provide additional mechanistic insights and help to identify molecular targets for therapeutic interventions in humans. 相似文献
46.
Jonas Gregor Wiese Sooruban Shanmugaratnam Birte Hcker 《Protein science : a publication of the Protein Society》2021,30(5):982
The ability to construct novel enzymes is a major aim in de novo protein design. A popular enzyme fold for design attempts is the TIM barrel. This fold is a common topology for enzymes and can harbor many diverse reactions. The recent de novo design of a four‐fold symmetric TIM barrel provides a well understood minimal scaffold for potential enzyme designs. Here we explore opportunities to extend and diversify this scaffold by adding a short de novo helix on top of the barrel. Due to the size of the protein, we developed a design pipeline based on computational ab initio folding that solves a less complex sub‐problem focused around the helix and its vicinity and adapt it to the entire protein. We provide biochemical characterization and a high‐resolution X‐ray structure for one variant and compare it to our design model. The successful extension of this robust TIM‐barrel scaffold opens opportunities to diversify it towards more pocket like arrangements and as such can be considered a building block for future design of binding or catalytic sites. 相似文献
47.
Ravi Vinayak Alexander C. van der Laan Rick Brill Ken Otteson Alex Andrus Esther Kuyl-Yeheskiely 《Nucleosides, nucleotides & nucleic acids》2013,32(7-9):1653-1656
Abstract Automated chemical synthesis of PNA and PNA-DNA chimera on a DNA synthesizer using the monomethoxytrityl/acyl protecting group strategy is described. 相似文献
48.
Breeding is limited by energetic or environmental constraints and long-lived species sometimes skip breeding opportunities. Environmental conditions may vary considerably across the geographic and elevational range of a species and species that can respond through variation in life history strategies are likely to maintain populations at the extremes of their ranges. The decision to skip breeding enables animals to adjust life history to circumstances, and plasticity in behavior allows implementation of adjustments. Elevational patterns suggest that breeding may be limited physiologically at high elevations (e.g., greater probability of skipped breeding; resources and environmental conditions more variable) in contrast to low elevations (probability of skipping breeding lower; resources and environmental conditions more predictable). We estimated the probabilities of survival and skipped breeding in a high-elevation population of common toads and compared estimates to existing data for common toads at low elevations, and to another toad species inhabiting a similar high elevation environment. Female common toads at high elevations tend to have high probabilities of skipping breeding and survival relative to data for common toads at low elevations, and appear to use a similar strategy of skipping breeding in response to similar environmental constraints as other toads at high elevations. We provide evidence of variability in this aspect of life history for common toads. Understanding variation in life history within widely distributed species is critical. Knowing that certain life history strategies are employed on a continuum informs conservation efforts, especially as impacts of climate change are likely to be different depending on elevation. 相似文献
49.
Kurt Reifenberg Fei Cheng Laura Twardowski Ines Küpper Elena Wiese Franziska Bollmann Hartmut Kleinert Manfred Blessing Karl J. Lackner Michael Torzewski 《PloS one》2013,8(12)
Clinical data have indicated a negative correlation between plasma TGFß1 concentrations and the extent of atherosclerosis and have thus led to the hypothesis that the pleiotropic cytokine may have anti-atherogenic properties. T-cells are currently discussed to significantly participate in atherogenesis, but the precise role of adaptive immunity in atherogenesis remains to be elucidated. TGFß1 is known to strongly modulate the function of T-cells, however, inhibition of TGFß1 signalling in T-cells of atherosclerosis-prone knock-out mice failed to unequivocally clarify the role of the cytokine for the development of atherosclerosis. In the present study, we thus tried to specify the role of TGFß1 in atherogenesis by using the murine CD2-TGFß1 transgenic strain which represents a well characterized model of T-cell specific TGFß1 overexpression. The CD2-TGFß1 transgenic mice were crossed to ApoE knock-out mice and quantity and quality of atherosclerosis regarding number of macrophages, smooth muscle cells, CD3 positive T-cells and collagen was analyzed in CD2-TGFß1 ApoE double mutants as well as non-transgenic ApoE controls on both normal and atherogenic diet of a duration of 8, 16 or 24 weeks, respectively. In all experimental groups investigated, we failed to detect any influence of TGFß1 overexpression on disease. Total number of CD3-positive T-lymphocytes was not significantly different in atherosclerotic lesions of CD2-TGFß1 ApoE−/− females and isogenic ApoE−/− controls, even after 24 weeks on the atherogenic diet. The synopsis of these data and our previous study on TGFß1 overexpressing macrophages suggests that potential effects of TGFß1 on atherosclerosis are most probably mediated by macrophages rather than T-cells. 相似文献
50.