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71.
Abstract: Past studies using penned deer provide conflicting results on the age when reliable predictions about antler growth potential in white-tailed deer (Odocoileus virginianus) can be made. We captured wild whitetail males via aerial net gun on 12 ranches in 5 counties in south Texas, USA, from 1999 to 2007 to determine if a reliable juvenile-to-adult relationship in antler development existed. We individually marked and released captured animals at the trap site after we took antler and body measurements. We recaptured marked animals as possible in subsequent years or until we obtained final measurements after legal harvest. Amount of growth in the first set of antlers in whitetail males was a poor predictor of antler growth at maturity. By 4.5 years of age there were no differences (P > 0.05) in antler measurements regardless of the amount of development of the first set of antlers at 1.5 years. We concluded culling of yearling males based on number of antler points would have little positive effect on overall antler quality in future years. 相似文献
72.
树鼩细胞周期蛋白T1 cDNA的克隆和序列分析 总被引:1,自引:0,他引:1
树鼩细胞不能感染HIV-1,但支持HIV-1进入靶细胞后的转录,可能是因为树鼩细胞周期蛋白T1(tsCycT1)能结合HIV-1的Tat蛋白。通过设计引物,用RT—PCR技术,获得全长为2175bp tsCycT1基因的cDNA。其核苷酸序列与人的CycT1(hCycT1)基因的cDNA有92.6%的相似性;由此推导出的氨基酸序列有94.1%相似性。其中,hCycT1和tsCycT1氨基端的1—272个氨基酸的相似性高达98.8%,氨基酸第261位点为半胱氨酸。这些结果提示,tsCycT1会和HIV-1的Tat结合,形成高亲和的、锌依赖的复合物,支持HIV-1转录。 相似文献
73.
MIRIAM LIEDVOGEL MARTA SZULKIN SARAH C. L. KNOWLES MATTHEW J. WOOD BEN C. SHELDON 《Molecular ecology》2009,18(11):2444-2456
The timing of reproduction in birds varies considerably within populations and is often under strong natural selection. Individual timing within years is dependent on a range of environmental factors in addition to having an additive genetic basis. In vertebrates, an increasing amount is known about the molecular basis for variation in biological timing. The Clock gene includes a variable poly-glutamine (poly-Q) repeat influencing behaviour and physiology. Recent work in birds, fish and insects has demonstrated associations between Clock genotype and latitude across populations, which match latitudinal variation in breeding time. In this study, we investigated the phenotypic correlates of variation in Clock genotype within a single blue tit Cyanistes caeruleus population over two successive breeding seasons. In females, but not in males, we observed a general trend for birds with fewer poly-Q repeats to breed earlier in the season. Incubation duration was shorter in both females and males with fewer repeats at the polymorphic Clock locus. Poly-Q Clock allele-frequency was homogenously distributed within the study population and did not exhibit any consistent environment-related variation. We further tested for effects of Clock genotype on reproductive success and survival, and found that females with fewer poly-Q repeats produced a higher number of fledged offspring. Our results therefore suggest that (i) selection in females, but not in males, for fewer poly-Q repeats may be operating, (ii) the across–population associations in timing of breeding involving this locus could be linked to variation within populations, and (iii) the Clock gene might be involved in local adaptation to seasonal environments. 相似文献
74.
LOUISE BACH JENSEN HILDE MUYLLE PAUL ARENS CLAUS H. ANDERSEN PREBEN BACH HOLM MARC GHESQUIERE BERNADETTE JULIER THOMAS LÜBBERSTEDT KLAUS K. NIELSEN JAN DE RIEK ISABEL ROLDN‐RUIZ NIELS ROULUND CHRIS TAYLOR BEN VOSMAN PHILIPPE BARRE 《Molecular ecology resources》2005,5(4):951-957
We report on the characterization and mapping of 76 simple sequence repeat (SSR) markers for Lolium perenne. These markers are publicly available or obtained either from genomic libraries enriched for SSR motifs or L. perenne expressed sequence tag (EST) clones. Four L. perenne mapping populations were used to map the SSR markers. A consensus linkage map of the four mapping populations containing 65 of the SSR markers is presented, together with primer information and a quality score indicating the usefulness of the SSR marker in different populations. The SSR markers identified all seven L. perenne linkage groups. 相似文献
75.
SIEMON H. S. NG ALAN CHANG GORDON D. BROWN BEN F. KOOP WILLIAM S. DAVIDSON 《Molecular ecology resources》2005,5(4):762-766
The detection of simple sequence repeats (SSRs) within expressed sequence tags (ESTs) connects potential microsatellite markers with specific genes, generating Type I markers. Using an in silico approach, we identified 1975 SSRs from the Genome Research on Atlantic Salmon Project EST database. We designed primers to amplify 158 SSRs, of which 65 amplified 76 loci (including 11 duplicated loci). Sixty‐one of the 76 loci were variable in 24 Atlantic salmon from seven populations, and 96% of these markers also amplify DNA from other salmonids. Functions for 16 of the SSR associated ESTs have been determined, confirming them as Type I markers. 相似文献
76.
JASON G. VOGEL BEN P. BOND-LAMBERTY† EDWARD A. G. SCHUUR STITH T. GOWER† MICHELLE C. MACK KARI E. B. O'CONNELL‡ DAVID W. VALENTINE§ ROGER W. RUESS¶ 《Global Change Biology》2008,14(7):1503-1516
A common hypothesis for northern ecosystems is that low soil temperatures inhibit plant productivity. To address this hypothesis, we reviewed how separate components of ecosystem carbon (C) cycling varied along a soil temperature gradient for nine well-drained, relatively productive boreal black spruce ( Picea mariana Mill. [B.S.P.]) forests in Alaska, USA, and Saskatchewan and Manitoba, Canada. Annual soil temperature [expressed as soil summed degree days (SDD)] was positively correlated with aboveground net primary productivity (ANPP), while negatively correlated with total belowground carbon flux (TBCF). The partitioning of C to ANPP at the expense of root processes represented a nearly 1 : 1 tradeoff across the soil temperature gradient, which implied that the amount of C cycling through these black spruce ecosystems was relatively insensitive to variation in SDD. Moreover, the rate at which C accumulated in the ecosystem since the last stand replacing fire was unrelated to SDD, but SDD was positively correlated to the ratio of spruce-biomass : forest-floor-mass. Thus, plant partitioning of C and the distribution of ecosystem C were apparently affected by soil temperature, although across regions, precipitation co-varied with soil temperature. These two factors likely correlated with one another because of precipitation's influence on soil heat balance, suggesting that a soil temperature–precipitation interaction could be responsible for the shifts in C allocation. Nonetheless, our results highlight that for this boreal ecosystem, ANPP and TBCF can be negatively correlated. In tropical and temperate forests, TBCF and ANPP have been reported as positively correlated, and our results may reflect the unique interactions between soil temperature, forest floor accumulation, rooting depth, and nutrient availability that characterize the black spruce forest type. 相似文献
77.
ALAN N. ANDERSEN ALARIC FISHER BEN D. HOFFMANN JOHN L. READ ROB RICHARDS 《Austral ecology》2004,29(1):87-92
Abstract Taken literally, the aim of biodiversity monitoring is to track changes in the biological integrity of ecosystems. Given the overwhelmingly dominant contribution of invertebrates to biodiversity, no biodiversity monitoring programme can be considered credible if invertebrates are not addressed effectively. Here we review the use of terrestrial invertebrates, with a particular focus on ants, as bioindicators in Australia in the context of monitoring biodiversity in Australia's rangelands. Ant monitoring systems in Australia were initially developed for assessing restoration success following mining, and have since been applied to a wide range of other land‐use situations, including grazing impacts in rangelands. The use of ants as bioindicators in Australia is supported by an extensive portfolio of studies of the responses of ant communities to disturbance, as well as by a global model of ant community dynamics based on functional groups in relation to environmental stress and disturbance. Available data from mining studies suggest that ants reflect changes in other invertebrate groups, but this remains largely undocumented in rangelands. The feasibility of using ants as indicators in land management remains a key issue, given the large numbers of taxonomically challenging specimens in samples, and a lack of invertebrate expertise within most land‐management agencies. However, recent work has shown that major efficiencies can be achieved by simplifying the ant sorting process, and such efficiencies can actually enhance rather than compromise indicator performance. 相似文献
78.
黄瓜化学成分的提取与研究 总被引:2,自引:0,他引:2
本文分别采用减压蒸馏-冷冻浓缩、微波-超声波萃取和固相微萃取(SPME)技术,对鲜黄瓜(带皮)、黄瓜皮、肉、籽进行了化学成分的提取及气相色谱-质谱(GC-MS)分析,共检测出109种化合物,其中大部分化合物尚未从黄瓜中分离得到.实验结果证明黄瓜皮及黄瓜籽中含有较多芳香类物质、生育酚、角鲨烯、姜烯、阿茶碱、亚油酸与油酸等营养物质. 相似文献
79.
在高寒矮嵩草(Kobresia humilis)草甸地区以太阳短波辐射为背景,建立了人工增强UV-B辐射的实验装置,每天增补15.8kJ.m^-2的辐射剂量,模拟平流层臭氧破坏约5%时近地表面太阳UV-B辐射的增强。观测表明:UV-B辐射的增强对麻花艽(Gentiana stramianea)植物的光合作用无明显的抑制或伤害作用。相反,在早晨补充UV-B辐射的短时间内,叶片的Pn随Gs的增大而有所提高。随着UV-B辐射时间的延长,在11:30-12:30,Pn和Gs有所降低。UV-B辐射时间进一步延长后(约14:00以后),处理和对照组叶片Pn和Gs的差异趋向不明显,增强太阳UV-B辐射后,麻花艽叶片的光合色素并无明显变化,UV-B吸收物质的含量无明显变化,麻花艽叶片厚度的直接测量表明,增强UV-B辐射能明显提高叶片的厚度。叶片厚度的增加可补偿增强UV-B辐射辐后引起的光合色素的光降解,改善单位叶面积为基础的光合速率,是高原植物对强UV-B辐射的一种适应方式。 相似文献
80.
Bcl-2 over-expression and activation of protein kinase C suppress the Trail-induced apoptosis in Jurkat T cells 总被引:8,自引:0,他引:8
GUO BEN CHANG YONG HUA XU Institute of Biochemistry Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of Sciences Yue-yang Road Shanghai China 《Cell research》2001,(2)
INTRODUCTIONThaillll (TNF-related apoptosis inducing ligand)is a recently described member of the TNF family.Like other members of the TNF ligand family) availcould induce apoptosis of neoplastically transformedcells by priVating cell surface death receptors ThailRI and ThaiLR212].Trail has been demonstrated to play an important role in homeostasis of immune system includ.lug eradication of the old lymphocytel3], actiVationinduced T cell deathI41, regulation Of T cen eXPansion by… 相似文献