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91.
采用不同浓度的草甘膦0.41 g/L、0.82 g/L、1.23 g/L、1.64g/L、2.05 g/L分别以胃毒和触杀法处理空心莲子草叶甲Agasicles hygrophila成虫,测定其乙酰胆碱酯酶(AChE)、羧酸酯酶(CarE)和谷胱甘肽S-转移酶(GSTs)比活力.试验结果表明:两种处理,草甘膦对AChE活力均有不同程度的抑制作用;对CarE活力影响较为显著,在2.05 g/L浓度下,胃毒处理CarE对α-乙酸萘酯(α-NA)和β-乙酸萘酯(β-NA)水解能力分别是对照组的50%和57%,触杀处理CarE对α-乙酸萘酯(α-NA)和β-乙酸荼酯(β-NA)水解能力分别是对照组的53%和59%;胃毒处理埘酶活力影响大于触杀处理,草甘膦对GSTs的活力影响不明显. 相似文献
92.
Molecular anatomy of the DNA damage and replication checkpoints 总被引:12,自引:0,他引:12
Cell cycle checkpoints are signal transduction pathways that enforce the orderly execution of the cell division cycle and arrest the cell cycle upon the occurrence of undesirable events, such as DNA damage, replication stress, and spindle disruption. The primary function of the cell cycle checkpoint is to ensure that the integrity of chromosomal DNA is maintained. DNA lesions and disrupted replication forks are thought to be recognized by the DNA damage checkpoint and replication checkpoint, respectively. Both checkpoints initiate protein kinase-based signal transduction cascade to activate downstream effectors that elicit cell cycle arrest, DNA repair, or apoptosis that is often dependent on dose and cell type. These actions prevent the conversion of aberrant DNA structures into inheritable mutations and minimize the survival of cells with unrepairable damage. Genetic components of the damage and replication checkpoints have been identified in yeast and humans, and a working model is beginning to emerge. We summarize recent advances in the DNA damage and replication checkpoints and discuss the essential functions of the proteins involved in the checkpoint responses. 相似文献
93.
MicroRNAs (miRNAs) have recently emerged as regulators of metastasis. We provide insight into the behavior of miR-221 in colorectal cancer (CRC) metastasis by showing that miR-221 is significantly upregulated in metastatic CRC cell lines and tissues. miR-221 overexpression enhances, whereas miR-221 depletion reduces CRC cell migration and invasion in vitro and metastasis in vivo. We identify RECK as a direct target of miR-221, reveal its expression to be inversely correlated with miR-221 in CRC samples and show that its re-introduction reverses miR-221-induced CRC invasiveness. Collectively, miR-221 is an oncogenic miRNA which may regulate CRC migration and invasion through targeting RECK. 相似文献
94.
Species diversity of the genus Osmundea (Ceramiales,Rhodophyta) in the Macaronesian region 下载免费PDF全文
María Machín‐Sánchez Florence Rousseau Line Le Gall Valéria Cassano Ana I. Neto Abel Sentíes Mutue T. Fujii María Candelaria Gil‐Rodríguez 《Journal of phycology》2016,52(4):664-681
Species diversity within the genus Osmundea in the Macaronesian region was explored by conducting a comprehensive sampling in the Azores, the Canary, and the Madeira archipelagos. Toward identification, all specimens were first observed alive to verify the absence of corps en cerise, a diagnostic character for the genus and morphometric data were measured (thallus length and width, first‐order branches length and width, branchlets length and width, cortical cell length and width in surface view, cortical cell length and width in transverse section). Specimens were sequenced for COI‐5P (39 specimens) and three species delimitation methods (Generalized Mixed Yule Coalescent, Automatic Barcode Gap Discovery method, and Poisson Tree Processes) were used to assess the threshold between infra‐ and interspecific relationships. Subsequently, one or several sequences of plastid‐encoded large subunit of RuBisCO (21 specimens) per delimited species were generated to assess the phylogenetic relationships among Macaronesian Osmundea. Moreover, for each delineated species, vegetative and reproductive anatomy was thoroughly documented and, when possible, specimens were either assigned to existing taxa or described as novel species. This integrative approach has provided data for (i) the presence of O. oederi, O. pinnatifida, and O. truncata in Macaronesia; (ii) the proposal of two novel species, O. prudhommevanreinei sp. nov. and O. silvae sp. nov.; and (iii) evidence of an additional species referred as “Osmundea sp.1,” which is a sister taxon of O. hybrida. 相似文献
95.
辽宁黄海海岸交错带的景观近几十来年变化很快,其中许多景观变化是有意识的人类活动或人工管理形成的景观设计可以看作是已经出现或即将出现的景观变化。由于这一区域海岸交错带有不同的海岸带类型,因而也就有了不同的景观设计方案。 相似文献
96.
97.
目的研究P63和TTF-1在肺癌各种类型组织中的表达及其意义。方法随机收集原发性肺癌组织标本53例(其中鳞癌16例,腺癌16例,小细胞癌14例,大细胞癌7例,均为中低分化程度癌组织),采用免疫组织化学S-P法分别检测P63蛋白和TTF-1蛋白在各种类型肺癌组织中的表达并结合二者表达的结果进行分析。结果二者的表达在肺癌细胞中定位于细胞核,呈棕黄色。在肺鳞癌、肺腺癌、肺小细胞癌和肺大细胞癌中,P63的阳性表达率分别为93.8%(15/16)、37.5%(6/16)、21.4%(3/14)、28.6%(2/7);TTF-1的阳性表达率分别为18.8%(3/16)、75%(12/16)、78.6%(11/14)、0%(0/7)。结论①P63在肺鳞癌中的表达水平较高,可以作为鉴别低分化鳞癌与低分化腺癌,小细胞癌的指标;②TTF-1在低分化腺癌和小细胞癌中的表达水平较高,对于肺癌组织类型和非癌组织的鉴别具有一定意义;③根据P63和TTF-1在肺癌组织的特异性表达,将二者联合起来有助于对低分化鳞癌和低分化腺癌以及低分化鳞癌和小细胞癌的鉴别诊断。 相似文献
98.
Recruitment is a complex process consisting of sequential stages affected by biotic interactions and abiotic factors. Assessment of these sequential stages and corresponding subprocesses may be useful in identifying the most critical stages. Accordingly, to assess the factors that may determine the altitudinal range limits of the high mountain Mediterranean plant Silene ciliata, a set of demographic stages, from flower production to establishment of 2‐yr‐old plants, and their influence on recruitment probability were examined using a step‐by‐step approach. We integrated florivory, pollination and pre‐dispersal seed predation as pre‐dispersal factors, and seedling emergence and survival as post‐dispersal determinants of recruitment. Three populations were monitored at the southernmost margin of the species along its local altitudinal range. Previous studies suggest that seediness is strongly limited by summer drought especially at the lower boundary of the species, a situation that may worsen under current global warming. Our results showed that recruitment was mainly limited by low seed production in the pre‐dispersal stage and low seedling emergence and survival in the post‐dispersal stage, probably due to environmental harshness in summer. By contrast, biotic factors responsible for propagule loss, such as flower and fruit predation, had a minor effect on the probability of plant recruitment. Although the relative importance of transition probabilities was similar among populations along the altitudinal range, comparatively lower flower production significantly reduced the number of recruited plants at the lowest altitude population. This demographic bottleneck, together with increased competition with other species favoured by climate warming, might collapse population growth and limit persistence at the lower altitudinal range of the species, raising its low local altitudinal edge. 相似文献
99.
番荔枝实蝇Ceratitis artortoe(Graham)是一种重要的外来人侵性检疫害虫.在广东口岸,其幼虫连续从入境旅客所携带的水果中被榆出.目前关于番荔枝实蝇潜在适生性分布的研究进行得很少,但对于我国的生物生态安全却有重要意义.本研究中,我们使用3种牛态位模型(ENFA模型,马氏典型性模型和Maxent模型)对番荔枝实蝇在中斟以及全球范尉内的潜在适生性分布区域进行了预测分析.结果显示:Maxent模型拥有最好的预测精确度,马氏典型件模型次之,而ENFA模型的预测精确度最差;Maxent模型和马氏典型性模型的预测精确度无显著性差异;根据Maxent模型的预测结果,番荔枝实蝇在中国的潜在适生区主要是广西、广东、海南以及云南的少部分地区.分析结果显示,番荔枝实蝇从境外传人中国南部地区并最终在上述地区定殖的风险可能性存在,但风险较小.另外,折刀法(Jackknife)分析显示,6种环境因子,例如地面霜冻频率、年平均降雨量、十月降雨量、四月降雨量、年最低温度以及蒸气压,对于番荔枝实蝇在全球和局部地区的分布模式有显著的影响. 相似文献
100.
采用室内控制生长条件的营养液培养技术,通过检测缺铁条件下20个中国春的Hope染色体代换系及其亲本中国春和Hope小麦植物铁载本分泌的动态变化规律以及植物铁载体分泌高峰期内5次测定值的汇总资料,对六倍体小麦PS分泌基因进行染色体定位。PS分泌率通过根分泌物对新形成的Fe(OH)3的活化能力进行测定,在缺铁症出现时每隔2,3天测定1次,随着缺铁失绿症严重程度的增加,PS分泌率呈现迅速增高再逐渐降低的 相似文献