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51.
蛾螺科三种螺的核型观察 总被引:5,自引:0,他引:5
本文介绍了蛾螺科三种螺的核型。水泡蛾螺(Buccinum pcmphigum)为2n=30,染色体的形态分类组成为16m+10sm+4st,NF=56;Plicifusus scissuratus为2n=34,染色体的形态分类组成为20m+10sm+4st,NF=64;香螺(Neptumea cumingi)为2n=60,染色体的形态分类组成为30m+22sm+8st,NF=112。 蛾螺科核型分析,显示贝类染色体数目及其形态与贝类进化有关。 相似文献
52.
It is widely held that any given virus uses only one type of nucleic acid for genetic information storage. However, this consensus has been challenged slightly by several recent studies showing that many RNA species are present within a range of DNA viruses that include Kaposi''s sarcoma-associated herpesvirus (KSHV). RNAs extracted from purified DNA virus particles exhibit great diversity in terms of length, abundance, temporal expression, cellular localization, and coding capacity during viral infection. In addition to known RNA species, the current study showed that small regulatory RNAs were present in KSHV virions. A large number of viral and cellular microRNAs (miRNAs), as well as unusual small RNAs (usRNAs), were detected in KSHV virions by using deep sequencing. Both viral and host miRNAs detected in small RNAs extracted from KSHV virions were further shown to colocalize with KSHV virions directly by in situ hybridization (ISH)-electron microscopy (EM) (ISH-EM). Some of these miRNAs were differentially present in the host cells and KSHV virions, suggesting that they are not randomly present in KSHV virions. The virional miRNAs could be transported into host cells, and they are biologically functional during de novo viral infection. Our study revealed miRNAs and usRNAs as a novel group of components in KSHV virions. 相似文献
53.
Xiaoke Zhang Yong Jiang Lei Liang Xiaofan Zhao Qi Li 《Frontiers of Biology in China》2009,4(1):111-116
The effects of inorganic fertilizers on soil nematode communities were studied in a long-term fertilization experimental field
in the Black Soil Region of Northeast China, where no fertilizer (CK), N fertilizer (N), combined application of N and P (NP),
combined application of N and K (NK), and combined application of N, P and K (NPK) were compared. The results showed that
the total nematode abundance was not affected significantly by inorganic fertilizers in the long-term field experiment. The
numbers of bacterivores increased significantly in the NP treatment compared to the CK treatment, and those of fungivores
and plant-parasites were inhibited in the NPK treatment. The similarity between CK and NPK treatment and the nematode diversity
were higher than in other treatments. The stability of the soil ecosystem was disturbed by the inorganic fertilizers, as indicated
by the change in MI values under different treatments. The response of soil nematodes mainly depended on the types of inorganic
fertilizers applied. 相似文献
54.
Duplication and expression analysis of multicopy miRNA gene family members in Arabidopsis and rice 总被引:1,自引:0,他引:1
To understand the expansion ofmulticopy microRNA (miRNA) families in plants, we localized the reported miRNA genes from Arabidopsis and rice to their chromosomes, respectively, and observed that 37% of 117 miRNA genes from Arabidopsis and 35% of 173 miRNA genes from rice were segmental duplications in the genome. In order to characterize whether the expression diversification has occurred among plant multicopy miRNA family members, we designed PCR primers targeting 48 predicted miRNA precursors from 10 families in Arabidopsis and rice. Results from RT-PCR data suggest that the transcribed precursors of members within the same miRNA family were present at different expression levels. In addition, although miRl60 and miR162 sequences were conserved in Arabidopsis and rice, we found that the expression patterns of these genes differed between the two species. These data suggested that expression diversification has occurred in multicopy miRNA families, increasing our understanding of the expression regulation of miRNAs in plants. 相似文献
55.
PAK5 is a member of the group B family of PAK serine/threonine kinases and is an effector for the Rho GTPase Cdc42. PAK5 is highly expressed in the brain and is expressed at lower levels in several other tissues. In cell lines, PAK5 has been shown to play a role in filopodia formation and neurite outgrowth. To examine the biological function of PAK5, we deleted the PAK5 gene in mice. The phenotypes of the PAK5-null mice are completely different from those of mice null for PAK4, another member of the group B PAK family. Unlike PAK4-null mice, which are embryonic lethal, PAK5-null mice develop normally and are fertile. The nervous system appears normal in the absence of PAK5, as do other tissues in which PAK5 is normally expressed. Our results suggest functional redundancy between PAK5 and other Rho GTPase targets. 相似文献
56.
The abnormal apoptosis of T cell subsets and possible involvement of IL-10 in systemic lupus erythematosus 总被引:9,自引:0,他引:9
To study the apoptosis of lymphocyte subpopulations in systemic lupus erythematosus (SLE) patients and the possible role of IL-10 in this apoptosis involved in the pathogenesis of SLE, three color fluorescence and flow cytometry were used to investigate the early apoptosis of lymphocyte subsets from freshly separated or cultured peripheral blood mononuclear cells (PBMCs). ELISA was employed to detect the levels of IL-10 in serum and the levels of sFas and sFasL in cultured PBMC supernatants, and the results of sFas and sFasL were confirmed by real-time PCR of Fas and FasL mRNA. The results showed that in cells from SLE patients, the apoptosis of CD3+, CD4+, and CD8+ T cells was distinctly increased, and the percentage of CD4+ cells and the CD4/CD8 ratio was significantly decreased, as compared with normal controls. The apoptosis of T lymphocytes cultured with SLE serum was markedly higher than that of cells cultured with control's serum. Blockade of interleukin-10 (IL-10) activation by an anti-IL-10 antibody reduced the SLE serum induced apoptosis of CD4+ and CD8+ T cells. The levels of sFas and sFasL in the culture supernatant and Fas and FasL mRNA expressions in cultured cells were significantly higher in the SLE serum-cultured groups, but decreased evidently in the presence of the anti-IL-10 antibody. Above findings suggested that SLE cells showed abnormally high apoptosis of T lymphocytes, especially of the CD4+ subpopulation, resulting in a decreased CD4/CD8 ratio. The high percentage of apoptotic T cells in SLE patients may be related to the high levels of IL-10 in SLE serum, as IL-10 may induce the abnormally activated T cells to trigger apoptosis via the Fas-FasL pathway. 相似文献
57.
PAK4 is a member of the group B family of p21-activated kinases. Its expression is elevated in many cancer cell lines, and activated PAK4 is highly transforming, suggesting that it plays an important role in tumorigenesis. Although most previous work was carried out with overexpressed PAK4, here we used RNA interference to knock down endogenous PAK4 in cancer cells. By studying PAK4 knockdown HeLa cells, we demonstrated that endogenous PAK4 is required for anchorage-independent growth. Because cell survival is a key part of tumorigenesis and anchorage-independent growth, we studied whether PAK4 has a role in protecting cells from cell death. To address this, we studied the role for PAK4 downstream to the tumor necrosis factor (TNF) alpha receptor. Although overexpressed PAK4 was previously shown to abrogate proapoptotic pathways, here we demonstrate that endogenous PAK4 is required for the full activation of prosurvival pathways induced by TNFalpha. Our results indicate that PAK4 is required for optimal binding of the scaffold protein TRADD to the activated TNFalpha receptor through both kinase-dependent and kinase-independent mechanisms. Consequently, activation of several prosurvival pathways, including the NFkappaB and ERK pathways, is reduced in the absence of PAK4. Interestingly, constitutive activation of the NFkappaB and ERK pathways could compensate for the lack of PAK4, indicating that these pathways function downstream to PAK4. The role for PAK4 in regulating prosurvival pathways is a completely new function for this protein, and the connection between PAK4 and cell survival under stress helps explain its role in tumorigenesis and development. 相似文献
58.
59.
Tissue inhibitor of metalloproteinase-1 promotes NIH3T3 fibroblast proliferation by activating p-Akt and cell cycle progression 总被引:1,自引:0,他引:1
Lu Y Liu S Zhang S Cai G Jiang H Su H Li X Hong Q Zhang X Chen X 《Molecules and cells》2011,31(3):225-230
Tissue inhibitor of metalloproteinase-1 (TIMP-1) plays various roles in cell growth in different cell types. However, few
studies have focused on TIMP-1’s effect on fibroblast cells. In this study, we investigated the effects of TIMP-1 overexpression
on NIH3T3 fibroblast proliferation and potential transduction signaling pathways involved. Overexpression of TIMP-1, by transfection
of the pLenti6/V5-DESTTIMP-1 plasmid, significantly promoted NIH3T3 proliferation as determined by the BrdU array. Neither
5 nor 15 nM GM6001 (matrix metalloproteinase system inhibitor) affected NIH3T3 proliferation, but 45 nM GM6001 inhibited proliferation.
TIMP-1 overexpression activated the p-Akt pathway, but not the p-ERK or p-p38 pathway. In TIMP-1-transfected cells, cyclinD1
was upregulated and p21CIP1 and p27KIP1 were downregulated, which promoted cell entry into the S and G2/M phases. The PI3-K inhibitor LY294002 abolished the TIMP-1-induced
effects. Overexpression of intracellular TIMP-1 stimulated NIH3T3 fibroblast proliferation in a matrix metalloproteinase (MMP)-independent
manner by activating the p-Akt pathway and related cell cycle progression. 相似文献
60.