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161.
Colleen M. McMichael Gregory D. Reynolds Lisa M. Koch Chao Wang Nan Jiang Jeanette Nadeau Fred D. Sack Max B. Gelderman Jianwei Pan Sebastian Y. Bednarek 《The Plant cell》2013,25(10):3910-3925
STOMATAL CYTOKINESIS DEFECTIVE1 (SCD1) encodes a putative Rab guanine nucleotide exchange factor that functions in membrane trafficking and is required for cytokinesis and cell expansion in Arabidopsis thaliana. Here, we show that the loss of SCD2 function disrupts cytokinesis and cell expansion and impairs fertility, phenotypes similar to those observed for scd1 mutants. Genetic and biochemical analyses showed that SCD1 function is dependent upon SCD2 and that together these proteins are required for plasma membrane internalization. Further specifying the role of these proteins in membrane trafficking, SCD1 and SCD2 proteins were found to be associated with isolated clathrin-coated vesicles and to colocalize with clathrin light chain at putative sites of endocytosis at the plasma membrane. Together, these data suggest that SCD1 and SCD2 function in clathrin-mediated membrane transport, including plasma membrane endocytosis, required for cytokinesis and cell expansion. 相似文献
162.
This study examined both socioeconomic and cultural factors in explaining ethnic differences in monitoring, behavioral control, and warmth—part of a series of coordinated studies presented in this special issue. Socioeconomic variables included mother's and father's educational levels, employment status, home ownership, number of siblings in the household, and single parent status. Cultural factors included nationality or ethnicity, immigrant status of child, mother's/father's age of arrival in the United States, mother's/father's English language use with the child, child's native fluency, and cultural values for independence and interdependence. The sample consisted of 591 European American, 123 African American, 1,614 Asian American, and 597 Latino students in the ninth grade. All the ethnic minority groups were higher than European Americans on behavioral control, and Latinos were also higher than European Americans on monitoring. However, European Americans were higher on parental warmth than Asian Americans and African Americans. These ethnic group differences primarily remained even after controlling for the socioeconomic factors. Finally, in analyses looking within the Asian and Latino groups, differences in parenting were found within both groups due to nationality or ethnicity, youth's fluency in the native language, and cultural values of interdependence, although values of independence were also related to the parenting of Asian Americans. 相似文献
163.
You-Bin Si Yan Xiang Chao Tian Xiong-Yuan Si Jing Zhou Dong-Mei Zhou 《Soil & Sediment Contamination》2013,22(1):72-84
Glyphosate [N-(phosphonomethyl)-glycine] is a herbicide widely used in large quantities in agricultural applications. It is also known to form complexes with metal ions, although its influence on metal behavior, such as lead (Pb) in soil, is not well understood. In this study, the adsorption and co-adsorption of Pb and glyphosate were determined on two soils [a red (RS) soil, Udic Ferrisol, and a yellow-brown (YB) soil, Udic Luvisol] of distinctly different chemical characteristics at varying pH conditions. Results indicate that the adsorption of lead and glyphosate strongly depends on soil types: the RS soil, characterized by a relatively high iron/aluminum content but a low pH and organic matter content, shows a much lower adsorption capacity for Pb but a higher sorption for glyphosate than the YB soil. The co-existence of Pb and glyphosate in soils resulted in complex interactions among Pb, glyphosate, Pb-glyphosate complexes, and soil minerals. The presence of glyphosate decreased Pb adsorption on the two soils, which was attributed primarily to the formation of soluble Pb-glyphosate complexes having relatively low affinities to soil surfaces. On the other hand, addition of Pb increased the adsorption of glyphosate on both soils, which was attributed to: (1) a decreased solution pH due to the ion exchange between Pb2+ and H+ on soil surfaces; and (2) increased sorption sites where Pb was adsorbed and acted as a bridge between glyphosate and the soil. The present study illustrates that the complex interactions among glyphosate, Pb, and soil may have important implications for the mobility and bioavailability of Pb in soil and should thus be considered in future environmental risk assessments. 相似文献
164.
Lei Li Den-bang Chen Chao Lin Kang Cao Yang Wan Xin-yu Zhao Chun-lai Nie Zhu Yuan Yu-quan Wei 《Apoptosis : an international journal on programmed cell death》2013,18(4):467-479
PNAS-4, a novel pro-apoptotic gene, was activated during the early response to DNA damage. Previous studies have shown that hPNAS-4 can inhibit tumor growth when over-expressed in ovarian cancer cells. However, the underlying action mechanism remains elusive. In this work, we found that hPNAS-4 expression was significantly increased in SKOV3 cells when exposed to cisplatin, methyl methanesulfonate or mitomycin C, and that its overexpression could induce proliferation inhibition, S phase arrest and apoptosis in A2780s and SKOV3 ovarian cancer cells. The S phase arrest caused by hPNAS-4 was associated with up-regulation of p21. p21 is p53-dispensable and correlates with activation of ERK, and activation of the Cdc25A-Cdk2-Cyclin E/Cyclin A pathway, while the pro-apoptotic effects of hPNAS-4 were mediated by activation of caspase-9 and -3 other than caspase-8, and accompanied by release of AIF, Smac and cytochrome c into the cytosol. Taken together, these data suggest a new mechanism by which hPNAS-4 inhibits proliferation of ovarian cancer cells by inducing S phase arrest and apoptosis via activation of Cdc25A-Cdk2-Cyclin E/Cyclin A axis and mitochondrial dysfunction-mediated caspase-dependent and -independent apoptotic pathways. To our knowledge, we provide the first molecular evidence for the potential application of hPNAS-4 as a novel target in ovarian cancer gene therapy. 相似文献
165.
CYP57B3 from Aspergillus oryzae was recently discovered to catalyze the ortho-hydroxylation of the soyisoflavone genistein. In the present study, the gene encoding CYP57B3 was fused with the reductase domain of the CYP102A1 gene (BM3R) from Bacillus megaterium, and recombinant Pichia pastoris harboring the P450 fusion gene was evaluated for its ability to produce ortho-hydroxydaidzein derivatives from daidzein. The results showed that 8-hydroxydaidzein (8-OHDe), 3′-hydroxydaidzein (3′-OHDe), and 6-hydroxydaidzein (6-OHDe) were produced during fermentation with a maximal conversion of 2.4, 0.9, and 36.3%, respectively. The maximal yield of 6-OHDe by the recombinant strain was 9.1 mg/l. To our knowledge, both the maximal yield and the conversion efficiency of 6-OHDe from daidzein in the present study are the highest among those reported in the literatures to date. The present study is also the first to demonstrate production of ortho-hydroxydaidzein derivatives using a fusion fungus cytochrome P450 enzyme. 相似文献
166.
Ahmed Hashim Toshiharu Abe Lijian Jin Yucheng Chang Zhi Chao Jin Jian Xun Sun George Hajishengallis Mike A. Curtis Richard P. Darveau 《Cellular microbiology》2013,15(8):1419-1426
The oral and intestinal host tissues both carry a heavy microbial burden. Although commensal bacteria contribute to healthy intestinal tissue structure and function, their contribution to oral health is poorly understood. A crucial component of periodontal health is the recruitment of neutrophils to periodontal tissue. To elucidate this process, gingival tissues of specific‐pathogen‐free and germ‐free wild‐type mice and CXCR2KO and MyD88KO mice were examined for quantitative analysis of neutrophils and CXCR2 chemoattractants (CXCL1, CXCL2). We show that the recruitment ofneutrophils to the gingival tissue does not require commensal bacterial colonization but is entirely dependent on CXCR2 expression. Strikingly, however, commensal bacteria selectively upregulate the expression of CXCL2, but not CXCL1, in a MyD88‐dependent way that correlates with increased neutrophil recruitment as compared with germ‐free conditions. This is the first evidence that the selective use of chemokine receptor ligands contributes to neutrophil homing to healthy periodontal tissue. 相似文献
167.
Zhigang Chen Xin He Wenjie Xia Qi Huang Zhigang Zhang Jun Ye Chao Ni Pin Wu Dang Wu Jinghong Xu Fuming Qiu Jian Huang 《PloS one》2013,8(12)
Background
The prognostic value of HIFs in colorectal cancer was evaluated in a large number of studies, but the conclusions were inconclusive. Meanwhile, clinicopathologic differences of HIF-1α and HIF-2α were rarely compared in recent studies.Methodology
Identical search strategies were used to search relevant literatures in the PubMed and Web of Science databases. The prognostic significances and clinicopathological differences of HIFs in CRC were analyzed.Principal Findings
A total of 23studies comprising 2984 CRC patients met the inclusion criteria. The results indicated that overexpressed HIFs were significantly associated with increase of mortality risk, including overall survival (OS) (HR 2.06 95%CI 1.55–2.74) and disease free survival (HR 2.84, 95%CI 1.87–4.31). Subgroup analysis revealed that both overexpressed HIF-1α and HIF-2α had correlations with worse prognosis. The pooled HRs were 2.01 (95% CI: 1.55–2.6) and 2.07(95% CI: 1.01–4.26). Further subgroup analysis on HIF-1α was performed by study location, number of patients, quality score and cut-off value. The results showed that HIF-1α overexpression was significantly associated with poor OS, particularly in Asian countries (HR 2.3, 95% CI: 1.74–3.01), while not in European or other countries. In addition, overexpression of HIF-1α was closely related with these clinicopathological features, including Dukes'' stages (OR 0.39, 95% CI: 0.17–0.89), UICC stages (OR 0.42 95% CI: 0.3–0.59), depth of invasion (OR 0.71, 95% CI: 0.51–0.99), lymphnode status (OR 0.49, 95% CI: 0.32–0.73) and metastasis (OR 0.29, 95% CI: 0.11–0.81). While overexpression of HIF-2α was only associated with grade of differentiation (OR 0.48, 95% CI: 0.29–0.81).Conclusions
This study showed that both HIF-1α and HIF-2α overexpression were associated with an unfavorable prognosis. HIF-1α overexpression seemed to be associated with worse prognosis in Asian countries. Additionally, HIF-1α and HIF-2α indicated distinct clinicopathologic features. 相似文献168.
Link Clustering (LC) is a relatively new method for detecting overlapping communities in networks. The basic principle of LC is to derive a transform matrix whose elements are composed of the link similarity of neighbor links based on the Jaccard distance calculation; then it applies hierarchical clustering to the transform matrix and uses a measure of partition density on the resulting dendrogram to determine the cut level for best community detection. However, the original link clustering method does not consider the link similarity of non-neighbor links, and the partition density tends to divide the communities into many small communities. In this paper, an Extended Link Clustering method (ELC) for overlapping community detection is proposed. The improved method employs a new link similarity, Extended Link Similarity (ELS), to produce a denser transform matrix, and uses the maximum value of EQ (an extended measure of quality of modularity) as a means to optimally cut the dendrogram for better partitioning of the original network space. Since ELS uses more link information, the resulting transform matrix provides a superior basis for clustering and analysis. Further, using the EQ value to find the best level for the hierarchical clustering dendrogram division, we obtain communities that are more sensible and reasonable than the ones obtained by the partition density evaluation. Experimentation on five real-world networks and artificially-generated networks shows that the ELC method achieves higher EQ and In-group Proportion (IGP) values. Additionally, communities are more realistic than those generated by either of the original LC method or the classical CPM method. 相似文献
169.
170.