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排序方式: 共有320条查询结果,搜索用时 218 毫秒
51.
二化螟水稻类群和茭白类群成虫产卵与幼虫寄主选择行为的比较研究 总被引:10,自引:1,他引:9
实验室木箱条件下进行的二化螟水稻类群与茭白类群成虫产卵选择性试验结果表明,两类群在水稻与茭白上所产的卵块和卵粒的分布及孵化率无显著差异;但均有将不能孵化卵产在非本寄主上的倾向.通过Y形嗅觉仪进行的幼虫寄主选择行为的试验结果显示,除茭白类群1龄幼虫对水稻与茭白的趋性分别为30.00%与66.67%,有显著差异(P≤0.05)外,1龄幼虫对两寄主组织的趋性无显著差异;对水稻与茭白叶片、叶鞘的趋性反应中,水稻类群4龄、6龄幼虫对叶片,2龄、4龄幼虫对叶鞘差异显著,而茭白类群2—6龄幼虫均差异显著(P≤0.05).研究结果表明,两类群已开始种下分化,其中茭白类群对本寄主的专化程度大于水稻类群。 相似文献
52.
ABSTRACT. In North America, zebra mussels ( Dreissena polymorpha ) are notoriously known as invasive species. The abundance of naked amoebae sampled from the shells of zebra mussels was compared with abundances from rock scrapings at approximately monthly intervals for 1 year. The sites were 2 km apart along the same shoreline. No significant difference in abundance of naked amoebae ( F =1.44; P ≤0.270) was detected for the two sampling sites. The combined data showed a minimum density of naked amoebae in winter, followed by peaks in early spring. The percent encysted increased from a low of 1% in the summer to 80% in early winter. 相似文献
53.
Two populations of Przewalski's naked carp Gymnocypris przewalskii, 30 individuals per population, were screened for 10 microsatellite loci. Moderate allele variation was found in these loci with two to eight alleles per locus. The expected and observed heterozygosity ranged from 0·019 to 0·805 and from 0·160 to 0·575, respectively. 相似文献
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青海湖裸鲤HIF-2α基因的克隆及其ODD功能域羟化分析 总被引:1,自引:0,他引:1
目的:克隆青海湖裸鲤低氧诱导因子-2α(HIF-2α)完整编码区,并分析HIF-2α ODD域与脯氨酸羟化酶3(PHD3)的相互作用。方法:通过RT-PCR与RACE克隆青海湖裸鲤H1F-2α基因序列,GSTpun-down法分析HIF-2α ODD域能否与PHD3相互结合。结果:获得的青海湖裸鲤HIF-2α eDNA序列长为3013bp,其中开放阅读框(0RF)为2502bp。GSTpull-down分析表明,HIF-2α ODD域羟化后能与PHD3形成酶/底物聚合物。结论:青海湖裸鲤HIF-2αODD域没有发生类似HIF-1α的羟化位点变异,能够被PHD3正常识别并结合。 相似文献
55.
Microbial Communities Associated with Tree Bark Foliose Lichens: A Perspective on their Microecology
O. Roger Anderson 《The Journal of eukaryotic microbiology》2014,61(4):364-370
Tree‐bark, foliose lichens occur widely on a global scale. In some locales, such as forests, they contribute a substantial amount of biomass. However, there are few research reports on microbial communities including eukaryotic microbes associated with foliose lichens. Lichens collected from tree bark at 11 locations (Florida, New York State, Germany, Australia, and the Arctic) were examined to determine the density and C‐biomass of bacteria and some eukaryotic microbes, i.e. heterotrophic nanoflagellates (HNF) and amoeboid protists. A rich microbial diversity was found, including large plasmodial slime molds, in some cases exceeding 100 μm in size. The densities of HNF and amoeboid protists were each positively correlated with densities of bacteria, r = 0.84 and 0.80, respectively (p < 0.01, N = 11 for each analysis) indicating a likely bacterial‐based food web. Microbial densities (number/g lichen dry weight) varied markedly across the geographic sampling sites: bacteria (0.7–13.1 × 108), HNF (0.2–6.8 × 106) and amoeboid protists (0.4–4.6 × 103). The ranges in C‐biomass (μg/g lichen dry weight) across the 11 sites were: bacteria (8.8–158.5), HNF (0.03–0.85), and amoeboid protists (0.08–540), the latter broad range was due particularly to absence or presence of large slime mold plasmodia. 相似文献
56.
淀粉粒蛋白(Starch granule proteins, SGPs)是一类与淀粉粒结合的微量蛋白, 其变异可能与淀粉特性相关。实验率先研究了我国青藏高原栽培青稞的SGP组成, 初步探索了所分离的SGP蛋白与淀粉合成的关系。青藏高原青稞的SGP组成存在多态性, 66份青稞材料中分离了10种主要的SGPs, 16种组合带谱。西藏青稞和四川青稞的SGP组成有很大差异, SGP组成具有地域差异性。不同组合带谱材料间淀粉含量差异显著性检验显示, 实验所分离的淀粉粒蛋白可能与淀粉的合成相关。 相似文献
57.
Valrie Bgay Branko Cirovic Alison J. Barker Robert Klopfleisch Daniel W. Hart Nigel C. Bennett Gary R. Lewin 《Open biology》2022,12(4)
Naked mole-rats (NM-R; Heterocephalus glaber) live in multi-generational colonies with a social hierarchy, and show low cancer incidence and long life-spans. Here we asked if an immune component might underlie such extreme physiology. The largest lymphoid organ is the spleen, which plays an essential role in responding to immunological insults and may participate in combating cancer and slowing ageing. We investigated the anatomy, molecular composition and function of the NM-R spleen using RNA-sequencing and histological analysis in healthy NM-Rs. Spleen size in healthy NM-Rs showed considerable inter-individual variability, with some animals displaying enlarged spleens. In all healthy NM-Rs, the spleen is a major site of adult haematopoiesis under normal physiological conditions. However, myeloid-to-lymphoid cell ratio is increased and splenic marginal zone showed markedly altered morphology when compared to other rodents. Healthy NM-Rs with enlarged spleens showed potentially better anti-microbial profiles and were much more likely to have a high rank within the colony. We propose that the anatomical plasticity of the spleen might be regulated by social interaction and gives immunological advantage to increase the lifespan of higher-ranked animals. 相似文献
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59.
Towards an understanding of how phloem amino acid composition shapes elevated CO2‐induced changes in aphid population dynamics 下载免费PDF全文
GERALDINE D. RYAN EMMA V. A. SYLVESTER BARRY J. SHELP JONATHAN A. NEWMAN 《Ecological Entomology》2015,40(3):247-257
1. The performance of foliage feeders tends to decrease under elevated CO2, but the responses of phloem‐feeding insects have been much more equivocal. As phloem tissues are less accessible than whole‐plant tissues, much less is known about how phloem composition is altered under elevated CO2 and the mechanisms driving changes in aphid performance. 2. In this study, the plant mechanisms underlying the performance of Rhopalosiphum padi aphids on Hordeum vulgare (barley) grown under ambient (390 ppm) and elevated (700 ppm) CO2 were examined. We used aphid stylectomy to sample pure phloem from plants in CO2‐controlled conditions and high‐performance liquid chromatography to analyse phloem samples for amino acid concentrations. 3. Aphid abundance significantly increased by 127% under elevated CO2. Consequently, plant biomass decreased under elevated CO2 in trials with herbivores present, possibly due to the increased herbivore load, but increased when aphids were absent. The intrinsic rate of population increase (rm) was significantly higher under elevated CO2; however, there were no statistically significant effects on aphid fecundity or development time. The concentration of individual amino acids tended to increase, although these increases were statistically significant in only a few cases. A principal components analysis revealed that the relative abundance (mol %) of those amino acids considered essential for aphids tended to increase under elevated CO2. 4. These results indicate that CO2 may affect nutrient translocation in plants in ways that are contrary to predictions about nitrogen metabolite responses to CO2. Such plant biochemical responses may underlie observations of improved phloem feeder performance under elevated CO2. 相似文献
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