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121.
Maarten A. Jongsma Fred Gould Mathieu Legros Limei Yang Joop J. A. van Loon Marcel Dicke 《Evolutionary ecology》2010,24(5):1017-1030
The major lepidopteran insect pests of cotton and maize harbor intra-specific variation for behavior determining the selection
of host plants for oviposition. Yet, the consequences of behavioral adaptation for fitness have neither been modeled nor monitored
for Bt cotton and maize crops, the most widely grown transgenic herbivore-resistant plants. Here, we present a general two-locus
heuristic model to examine potential outcomes of natural selection when pest populations initially have low frequencies of
alleles for both physiological and behavioral adaptation to Bt crops. We demonstrate that certain ecological conditions allow for the evolution of behavioral choices favoring alternative
oviposition hosts that limit the increase in resistance alleles, even when they are phenotypically dominant. These results
have implications for current refuge policies, which should be adapted to promote the evolution of certain behavioral choices
for alternative oviposition hosts in addition to dilution of physiological resistance alleles. Collection of data on oviposition
host preference as a component of monitoring schemes will provide important insights into mechanisms underlying the durability
of Bt-transgenic host-plant resistance. 相似文献
122.
123.
The insulin receptor was solubilized from turkey erythrocyte membranes by extraction with 1% beta-octylglucopyranoside. Insulin binding was enhanced when the solubilized material was reconstituted in phospholipid vesicles. The affinity of the reconstituted vesicles for various insulins was similar to that of the intact membranes: porcine insulin greater than proinsulin greater than desoctapeptide insulin. A curvilinear Scatchard plot was obtained for insulin binding to the reconstituted system at 15 degrees C. A high affinity association constant of 1.4 x 10(9) M-1 was obtained from the Scatchard plot. This is a four-fold increase over the value for the turkey erythrocyte membrane, which contains more highly saturated phospholipids. This suggests that the insulin receptor may be sensitive to the lipid composition of the membranes in which it is embedded. 相似文献
124.
Sargan DR Withers D Pettitt L Squire M Gould DJ Mellersh CS 《The Journal of heredity》2007,98(5):534-538
Primary lens luxation (PLL), a painful and blinding inherited condition, is common in several breeds of terrier. Here we have examined the Veterinary Medical Database of patient encounters and Canine Eye Registration Foundation (CERF) cases records for the last 10 years and found the diagnosis recorded in 85 breeds. We have performed association analysis using a genome-wide microsatellite screen to map mutations underlying the condition in miniature bull terriers and Lancashire heelers. These studies show microsatellite alleles in disequilibrium with disease status with highest support in a 6.3-Mbp region in the central part of chromosome 3 (-log P(max) = 6.4). The same region also shows an association to the disease in Tibetan terriers. Tight junction protein-1 (TJP1) is a positional candidate to contain the PLL mutation. All recognized exons and splice junctions of TJP1 have been sequenced from affected, obligate carrier and control Lancashire heeler dogs. Several polymorphisms have been found, but these are not likely to cause the disease. 相似文献
125.
How widespread is adult neurogenesis in mammals? 总被引:6,自引:0,他引:6
Gould E 《Nature reviews. Neuroscience》2007,8(6):481-488
It is now widely accepted that neurogenesis occurs in two regions of the adult mammalian brain--the hippocampus and the olfactory bulb. There is evidence for adult neurogenesis in several additional areas, including the neocortex, striatum, amygdala and substantia nigra, but this has been difficult to replicate consistently other than in the damaged brain. The discrepancies may be due to variations in the sensitivity of the methods used to detect new neurons. 相似文献
126.
The fusion of GLUT4-containing vesicles with the plasma membrane of adipocytes is a key facet of insulin action. This process is mediated by the formation of functional soluble N-ethylmaleimide–sensitive factor attachment protein receptor (SNARE) complexes between the plasma membrane t-SNARE complex and the vesicle v-SNARE or VAMP. The t-SNARE complex consists of Syntaxin4 and SNAP23, and whereas many studies identify VAMP2 as the v-SNARE, others suggest that either VAMP3 or VAMP8 may also fulfil this role. Here we characterized the levels of expression, distribution, and association of all the VAMPs expressed in 3T3-L1 adipocytes to provide the first systematic analysis of all members of this protein family for any cell type. Despite our finding that all VAMP isoforms form SDS-resistant SNARE complexes with Syntaxin4/SNAP23 in vitro, a combination of levels of expression (which vary by >30-fold), subcellular distribution, and coimmunoprecipitation analyses lead us to propose that VAMP2 is the major v-SNARE involved in GLUT4 trafficking to the surface of 3T3-L1 adipocytes. 相似文献
127.
Climate‐related genetic variation in drought‐resistance of Douglas‐fir (Pseudotsuga menziesii) 下载免费PDF全文
Sheel Bansal Constance A. Harrington Peter J. Gould J. Bradley St.Clair 《Global Change Biology》2015,21(2):947-958
There is a general assumption that intraspecific populations originating from relatively arid climates will be better adapted to cope with the expected increase in drought from climate change. For ecologically and economically important species, more comprehensive, genecological studies that utilize large distributions of populations and direct measures of traits associated with drought‐resistance are needed to empirically support this assumption because of the implications for the natural or assisted regeneration of species. We conducted a space‐for‐time substitution, common garden experiment with 35 populations of coast Douglas‐fir (Pseudotsuga menziesii var. menziesii) growing at three test sites with distinct summer temperature and precipitation (referred to as ‘cool/moist’, ‘moderate’, or ‘warm/dry’) to test the hypotheses that (i) there is large genetic variation among populations and regions in traits associated with drought‐resistance, (ii) the patterns of genetic variation are related to the native source‐climate of each population, in particular with summer temperature and precipitation, (iii) the differences among populations and relationships with climate are stronger at the warm/dry test site owing to greater expression of drought‐resistance traits (i.e., a genotype × environment interaction). During midsummer 2012, we measured the rate of water loss after stomatal closure (transpirationmin), water deficit (% below turgid saturation), and specific leaf area (SLA, cm2 g?1) on new growth of sapling branches. There was significant genetic variation in all plant traits, with populations originating from warmer and drier climates having greater drought‐resistance (i.e., lower transpirationmin, water deficit and SLA), but these trends were most clearly expressed only at the warm/dry test site. Contrary to expectations, populations from cooler climates also had greater drought‐resistance across all test sites. Multiple regression analysis indicated that Douglas‐fir populations from regions with relatively cool winters and arid summers may be most adapted to cope with drought conditions that are expected in the future. 相似文献
128.
Gould CJ Maiti S Michelot A Graziano BR Blanchoin L Goode BL 《Current biology : CB》2011,21(5):384-390
Formins are a large family of actin assembly-promoting proteins with many important biological roles. However, it has remained unclear how formins nucleate actin polymerization. All other nucleators are known to recruit actin monomers as a central part of their mechanisms. However, the actin-nucleating FH2 domain of formins lacks appreciable affinity for monomeric actin. Here, we found that yeast and mammalian formins bind actin monomers but that this activity requires their C-terminal DAD domains. Furthermore, we observed that the DAD works in concert with the FH2 to enhance nucleation without affecting the rate of filament elongation. We dissected this mechanism in mDia1, mapped nucleation activity to conserved residues in the DAD, and demonstrated that DAD roles in nucleation and autoinhibition are separable. Furthermore, DAD enhancement of nucleation was independent of contributions from the FH1 domain to nucleation. Together, our data show that (1) the DAD has dual functions in autoinhibition and nucleation; (2) the FH1, FH2, and DAD form a tripartite nucleation machine; and (3) formins nucleate by recruiting actin monomers and therefore are more similar to other nucleators than previously thought. 相似文献
129.
Delivery of the glucose transporter type 4 (GLUT4) from an intracellular location to the cell surface in response to insulin represents a specialized form of membrane traffic, known to be impaired in the disease states of insulin resistance and type 2 diabetes. Like all membrane trafficking events, this translocation of GLUT4 requires members of the SNARE family of proteins. Here, we discuss two SNARE complexes that have been implicated in insulin-regulated GLUT4 traffic: one regulating the final delivery of GLUT4 to the cell surface in response to insulin and the other controlling GLUT4's intracellular trafficking. 相似文献
130.
Chen Z Phillips LK Gould E Campisi J Lee SW Ormerod BK Zwierzchoniewska M Martinez OM Palmer TD 《PloS one》2011,6(3):e14787