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31.
32.
家蚕蛹在复眼着色期,经4℃冷藏24小时后,可被Ac NPV(苜蓿银纹夜蛾核多角体病毒)感染。在蛹体内复制出的多角体大小差异较大,且比在昆虫Sf—21细胞中繁殖的Ac NPV和在蚕蛹体内形成的Bm NPV多角体小。在蛹体内繁殖的Ac NPV的游离病毒可以回返感染Sf—21细胞。由蚕蛹内分离的Ac NPV基因组DNA的限制性内切酶图谱与野生型的Ac NPV相同。以上结果证明Ac NPV可以在蚕蛹体内复制。含HBsAg基因(人乙肝表面抗原)的重组Ac NPV亦可感染家蚕蛹,并能正确表达外源基因。此外,还发现化蛹后第2天的家蚕蛹被注射约5×10~5PFU的Ac NPV,可诱导“人工滞育蛹”现象的发生,在25℃经过30天后蛹仍存活,发育停滞在复眼着色前阶段。 相似文献
33.
香蕉ACC氧化酶基因(MAO3)的克隆及其表达特性分析 总被引:3,自引:0,他引:3
根据同源扩增得到香蕉(Musa acuminata) ACC氧化酶基因(MAO3) 的核心部分, 再通过3'和5'RACE扩增上、下游序列以及Genome-Walker的方法得到启动子部分, 共获得3 718 bp长度的序列。将所得结果进行聚类分析, 发现香蕉中ACC氧化酶的氨基酸序列非常保守, 各序列间的同一性高达99% ,与单子叶植物和双子叶植物中ACC氧化酶的氨基酸序列的同源性在66.7%~71.8%之间。组织原位杂交试验表明MAO3基因的表达具有组织特异性, 初步认为是在韧皮部筛管组织中特异表达。运用实时荧光定量PCR技术, 实时监测到了MAO3基因和香蕉乙烯受体基因ERS2受机械伤诱导的定量变化。 相似文献
34.
35.
AIM:To investigate the effect of LY980503(a benflumetol derivative)on multidrug resistance of tumor cell line using DNA microarray.METHODS:Total RNA was extracted from multidrug resistant MCF/DOX cell line. cDNA microarray containing 320 cDNAs was used to detect the gene expression profile.RESULTS:9 down-regulated genes and 1 up-regulated gene were identified after multidrug resistant MCF/DOX cells were treated with LY980503.CONCLUSION:LY980503 can effectively reverse the resistance of MCF/DOX to DOX in vitro by adjusting the expression of multi-genes. 相似文献
36.
额尔齐斯河流域生态系统格局及变化 总被引:8,自引:4,他引:8
本文首先对额尔齐斯河流域气候,地貌,水文等环境因子特征进行了评述,进而阐述了流域生态系统的特征和格局以及在自然和人为干扰作用下的变化。分析结果表明在自然干扰作用下流域生态系统的格局与流域水文情势变化相适应,处于准稳定变化状态,而在人为对流域水文情势扰动下,流域生态系统的格局间接地受到影响。从而产生新的格局,其作用的强度,持久性和生态系统的格局变化程度过错大于大于自然干扰作用下的变化。引额调水工程对额尔齐斯河流域河谷生态系统内部单元格局变化具有重要影响。 相似文献
37.
Ludwig John A. Eager Robert W. Bastin Gary N. Chewings Vanessa H. Liedloff Adam C. 《Landscape Ecology》2002,17(2):157-171
The cover, number, size, shape, spatial arrangement and orientation of vegetation patches are attributes that have been used
to indicate how well landscapes function to retain, not ‘leak’, vital system resources such as rainwater and soil. We derived
and tested a directional leakiness index (DLI) for this resource retention function. We used simulated landscape maps where
resource flows over map surfaces were directional and where landscape patch attributes were known. Although DLI was most strongly
related to patch cover, it also logically related to patch number, size, shape, arrangement and orientation. If the direction
of resource flow is multi-directional, a variant of DLI, the multi-directional leakiness index (MDLI) can be used. The utility
of DLI and MDLI was demonstrated by applying these indices to three Australian savanna landscapes differing in their remotely
sensed vegetation patch attributes. These leakiness indices clearly positioned these three landscapes along a function-dysfunction
continuum, where dysfunctional landscapes are leaky (poorly retain resources).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
38.
AIM and METHODS: Total RNA was extracted from 6th rat subcultured pulmonary artery smooth muscle cells(PASMC) exposed to continual chronic hypoxia or normoxia and the effects of chronic hypoxia on the changes of Kv1.3,Kv2.1,Kv3.1 mRNA in cultured PASMC induced by acute hypoxia were studied by semiquantitative RT-PCR in vitro. RESULTS:①Kv1.3,Kv2.1,Kv3.1 genes were found to be expressed in PASMC of rats exposed either to hypoxia or normxia.②The expression of Kv2.1 and Kv3.1 in 6th subcultured of PASMC in normaxia group could be upregulated by exposure to acute hypoxia,the levels of Kv2.1 and Kv3.1 mRNA were significantly increased from 0.646±0.092, 0.782±0.104 to 1.059±0.134, 0.985±0.116,respectively (P<0.01,n=5). ③PASMC cultured continuously in chronic hypoxia for 6 subcultures and then exposed to normoxia for 12 h,thereafter the expression of Kv2.1 and Kv3.1 were downregulated by acute hypoxia for 6 hours.The level of Kv2.1 mRNA was significantly decreased from 1.008±0.117 to 0.649±0.097 (P<0.01,n=5). CONCLUSION:Kv2.1,Kv3.1 genes might be oxygen sensitive genes.Chronic hypoxia might change the response of these Kv genes of PASMC to acute hypoxia and down-regulate its expression,which might probably decrease the role of Kv in HPV. 相似文献
39.
AIM: IL-12 acts upon Tlymphocytes and activates its receptor complexes of β1/β2,and so IL-12 can regulate TH1/TH2 balance. Our study is aimed at IL-12-inducing apoptosis of Tcells and expression and signal transduction of Fas/FasLduring Tcell apoptosis. METHODS: The apoptosis of Tcells was detected by Annexin Vstaining cytometry and the expression of Fas/FasLunder different inhibitors were detected by semi-quantitative PCR. RESULTS: IL-12 induced the human leukemic Tcell line(TIB-152) and the human lymphoma Tcell line(HTB-176) and the normal human Tcells to undergo apoptosis. The FasLexpression at 6 hours after treatment with IL-12 increased apparently, and reached the max at 24 hours, and FasLexpression induced by IL-12 was inhibited by PKCinhibitor. But IL-12 did not influence Fas expression. CONCLUSIONS: IL-12 can induce Tcells to undergo apoptosis which is characterized by early membrane changes, the inducing effect is correlated with the concentration of IL-12 and the maturation of Tcells. FasLparticipates in the progression of Tcell apoptosis as a apoptosis mediator, and the effect of IL-12 on FasLexpression may be related with PKCpathway. 相似文献
40.
Henk-jan Schoonbeek Johannes G.M. van Nistelrooy Maarten A. de Waard 《European journal of plant pathology / European Foundation for Plant Pathology》2003,109(9):1003-1011
The role of multiple ATP-binding cassette (ABC) and major facilitator superfamily (MFS) transporter genes from the plant pathogenic fungus Botrytis cinerea in protection against natural fungitoxic compounds was studied by expression analysis and phenotyping of gene-replacement mutants. The expression of 11 ABC (BcatrA–BcatrK) and three MFS genes (Bcmfs1, Bcmfs2 and Bcmfs4) was studied. All genes showed a low basal level of expression, but were differentially induced by treatment with cycloheximide and the plant defence compounds camptothecin, eugenol, psoralen, resveratrol and rishitin. The latter compounds induced expression of BcatrB at a high level. Eugenol was more toxic to BcatrB gene-replacement mutants than to the control isolates. Eugenol also caused an instantaneous increase in mycelial accumulation of the fungicide fludioxonil, a known substrate of BcatrB. However, there was no difference in virulence between the wild-type and BcatrB gene-replacement mutants on Ocimum basilicum, a plant known to contain eugenol. The results indicate that BcatrB is a transporter of lipophilic compounds, such as eugenol, but its role in virulence remains uncertain. 相似文献