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201.
Age-related macular degeneration (AMD) is a leading cause of blindness in the developed world. The retinal pigment epithelium (RPE) is a critical site of pathology in AMD and αB crystallin expression is increased in RPE and associated drusen in AMD. The purpose of this study was to investigate the role of αB crystallin in sodium iodate (NaIO3)-induced retinal degeneration, a model of AMD in which the primary site of pathology is the RPE. Dose dependent effects of intravenous NaIO3 (20-70 mg/kg) on development of retinal degeneration (fundus photography) and RPE and retinal neuronal loss (histology) were determined in wild type and αB crystallin knockout mice. Absence of αB crystallin augmented retinal degeneration in low dose (20 mg/kg) NaIO3-treated mice and increased retinal cell apoptosis which was mainly localized to the RPE layer. Generation of reactive oxygen species (ROS) was observed with NaIO3 in mouse and human RPE which increased further after αB crystallin knockout or siRNA knockdown, respectively. NaIO3 upregulated AKT phosphorylation and peroxisome proliferator–activator receptor–γ (PPARγ) which was suppressed after αB crystallin siRNA knockdown. Further, PPARγ ligand inhibited NaIO3-induced ROS generation. Our data suggest that αB crystallin plays a critical role in protection of NaIO3-induced oxidative stress and retinal degeneration in part through upregulation of AKT phosphorylation and PPARγ expression.  相似文献   
202.
The adjuvant effects of Lactobacillus acidophilus on DNA vaccination are not fully understood. It has been hypothesized that swine-derived Lactobacillus acidophilus SW1 (LASW1) could function as an immune adjuvant to enhance antigen-specific immune responses after foot-and-mouth disease (FMD) DNA vaccination in mice. To evaluate the effect of oral LASW1 on the immune response to a DNA vaccine (pRC/CMV-vp1) harboring FMD VP1 gene, anti-FMDV antibody and its isotypes, T-cell proliferation, and cytokine detection were investigated. The results showed that LASW1 was able to enhance FMDV-specific antibody levels and FMDV-neutralizing antibodies. After a booster vaccine, the anti-FMDV antibody titers and FMDV-neutralizing antibodies levels induced by pRC/CMV-vp1 were higher in mice treated with LSAW1 than in the group immunized with pRC/CMV-vp1 alone (the control). Using T-cell proliferation, the stimulation index of the LASW1 group was significantly higher in response to ConA and 146S antigen (P<0.05) than in the control group. Importantly, higher concentrations of IFN-γ and IFN-γ-producing cells were also observed in splenocytes isolated from the experimental LASW1 mice, indicating that INF-γ secretion is important to the immune response to LASW1. The results indicate that LASW1 is a promising immune adjuvant in DNA vaccination against FMD when administrated orally.  相似文献   
203.
Tuberculosis incidence among aborigines is significantly higher than for Han Chinese in Taiwan, but the extent to which Mycobacterium tuberculosis (MTB) strain characteristics contribute to this difference is not well understood. MTB isolates from aborigines and Han Chinese living in eastern and southern Taiwan, the major regions of aborigines, were analyzed by spoligotyping and 24-loci MIRU-VNTR. In eastern Taiwan, 60% of aboriginal patients were ≤20 years old, significantly younger than the non-aboriginal patients there; aborigines were more likely to have clustered MTB isolates than Han Chinese (odds ratio (OR) = 5.98, p<0.0001). MTB lineages with high clustering were EAI (54.9%) among southern people, and Beijing (62.5%) and Haarlem (52.9%) among eastern aborigines. Resistance to first-line drugs and multidrug resistance (MDR) were significantly higher among eastern aborigines (≥15%) than in any other geographic and ethnic group (p<0.05); MDR was detected in 5 of 28 eastern aboriginal patients ≤20 years old. Among patients from the eastern region, clustered strains (p = 0.01) and aboriginal ethnicity (p = 0.04) were independent risk factors for MDR. The lifestyles of aborigines in eastern Taiwan may explain why the percentage of infected aborigines is much higher than for their Han Chinese counterparts. The significantly higher percentage of the MDR-MTB strains in the aboriginal population warrants close attention to control policy and vaccination strategy.  相似文献   
204.
Developing sustainable management practices including appropriate residue removal and nitrogen (N) fertilization for bioenergy sorghum is critical. However, the effects of residue removal and N fertilization associated with bioenergy sorghum production on soil organic carbon (SOC) are less studied compared to other crops. The objective of our research was to assess the impacts of residue removal and N fertilization on biomass yield and SOC under biomass sorghum production. Field measurements were used to calibrate the DNDC model, then verified the model by comparing simulated results with measured results using the field management practices as agronomic inputs. Both residue removal and N fertilization affected bioenergy sorghum yields in some years. The average measured SOC at 0–50 cm across the treatments and the time-frame ranged from 47.5 to 78.7 Mg C ha−1, while the simulated SOC was from 56.3 to 67.3 Mg C ha−1. The high correlation coefficients (0.65 to 0.99) and low root mean square error (3 to 18) between measured and simulated values indicate the DNDC model accurately simulated the effects of residue removal with N fertilization on bioenergy sorghum production and SOC. The model predictions revealed that there is, in the long term, a trend for higher SOC under bioenergy sorghum production regardless of residue management.  相似文献   
205.
Synthetic high polymer flocculants, frequently utilized for flocculating efficiency and low cost, recently have been discovered as producing increased risk to human health and the environment. Development of a more efficient and environmentally sound alternative flocculant agent is investigated in this paper. Bioflocculants are produced by microorganisms and may exhibit a high rate of flocculation activity. The bioflocculant ETH-2, with high flocculating activity (2849 mg Kaolin particle/mg ETH-2), produced by strain Enterobacter sp. isolated from activated sludge, was systematically investigated with regard to its production, characterization, and flocculation mechanism. Analyses of microscopic observation, zeta potential and ETH-2 structure demonstrates the bridging mechanism, as opposed to charge neutralization, was responsible for flocculation of the ETH-2. ETH-2 retains high molecular weight (603 to 1820 kDa) and multi-functional groups (hydroxyl, amide and carboxyl) that contributed to flocculation. Polysaccharides mainly composed of mannose, glucose, and galactose, with a molar ratio of 1∶2.9∶9.8 were identified as the active constituents in bioflocculant. The structure of the long backbone with active sites of polysaccharides was determined as a primary basis for the high flocculation activity. Bioflocculant ETH-2 is cation independent, pH tolerant, and thermally stable, suggesting a potential fit for industrial application.  相似文献   
206.
The Peranakan Chinese are culturally unique descendants of immigrants from China who settled in the Malay Archipelago ∼300–500 years ago. Today, among large communities in Southeast Asia, the Peranakans have preserved Chinese traditions with strong influence from the local indigenous Malays. Yet, whether or to what extent genetic admixture co-occurred with the cultural mixture has been a topic of ongoing debate. We performed whole-genome sequencing (WGS) on 177 Singapore (SG) Peranakans and analyzed the data jointly with WGS data of Asian and European populations. We estimated that Peranakan Chinese inherited ∼5.62% (95% confidence interval [CI]: 4.76–6.49%) Malay ancestry, much higher than that in SG Chinese (1.08%, 0.65–1.51%), southern Chinese (0.86%, 0.50–1.23%), and northern Chinese (0.25%, 0.18–0.32%). A sex-biased admixture history, in which the Malay ancestry was contributed primarily by females, was supported by X chromosomal variants, and mitochondrial (MT) and Y haplogroups. Finally, we identified an ancient admixture event shared by Peranakan Chinese and SG Chinese ∼1,612 (95% CI: 1,345–1,923) years ago, coinciding with the settlement history of Han Chinese in southern China, apart from the recent admixture event with Malays unique to Peranakan Chinese ∼190 (159–213) years ago. These findings greatly advance our understanding of the dispersal history of Chinese and their interaction with indigenous populations in Southeast Asia.  相似文献   
207.
We have previously demonstrated that halofuginone, a low molecular weight quinazolinone alkaloid, is a potent inhibitor of collagen alpha1(I) and matrix metalloproteinase 2 (MMP-2) gene expression. Halofuginone also effectively suppresses tumor progression and metastasis in mice. These results together with the well-documented role of extracellular matrix (ECM) components and matrix degrading enzymes in formation of new blood vessels led us to investigate the effect of halofuginone on the angiogenic process. In a variety of experimental system, representing sequential events in the angiogenic cascade, halofuginone treatment resulted in profound inhibitory effect. Among these are the abrogation of endothelial cell MMP-2 expression and basement membrane invasion, capillary tube formation, and vascular sprouting, as well as deposition of subendothelial ECM. The most conclusive anti-angiogenic activity of halofuginone was demonstrated in vivo (mouse corneal micropocket assay) by showing a marked inhibition of basic fibroblast growth factor (bFGF) -induced neovascularization in response to systemic administration of halofuginone, either i.p. or in the diet. The ability of halofuginone to interfere with key events in neovascularization, together with its oral bioavailability and safe use as an anti-parasitic agent, make it a promising drug for further evaluation in the treatment of a wide range of diseases associated with pathological angiogenesis.  相似文献   
208.
渤海南部半滑舌鳎的食性及摄食的季节性变化   总被引:25,自引:0,他引:25  
窦硕增  杨纪明 《生态学报》1992,12(4):368-376
本文研究了渤海南部半滑鳎的食性及其摄食的季节性变化,胃食物分析结果表明,半滑舌鳎为底栖生物食性鱼类,以虾类,蟹类,双壳类及部分中下层小型鱼类为主要食物,兼食一些多毛类,头足类,腹足类,棘皮动物及海葵,半滑舌鳎终年摄食,其摄食强度的周年变化不大,半滑舌鳎常年捕食鲜明鼓虾,日本鼓虾,口虾蛄,隆线强蟹及泥古隆背蟹等。夏季加强捕食小刀蛏,凸壳肌蛤等双壳类,降春季外还捕食一些以虾虎鱼为主的中下层小型鱼类。  相似文献   
209.
通过形成类胚体诱导人羊水多能干细胞向心肌细胞分化   总被引:3,自引:1,他引:3  
由人羊水中分离羊水多能性干细胞,通过形成类胚体诱导其向心肌细胞分化.取人羊水标本进行体外培养,分离得到人羊水干细胞,已连续传代培养至42代,采用免疫细胞化学、RT-PCR和流式细胞仪技术对羊水干细胞的生物学特性进行检测.取10~15代羊水干细胞,悬浮培养使其形成类胚体,进而向心肌细胞诱导分化.培养的羊水干细胞呈成纤维样,表达部分胚胎干细胞特异标志基因,悬浮培养可形成类胚体.类胚体碱性磷酸酶(AP)检测呈阳性,表达三胚层特异标志基因fgf5、ζ-globin和α-fetoprotein.羊水干细胞形成类胚体后进行诱导,得到α-actin阳性细胞,表达心肌细胞特异标志基因Tbx5、Nkx2.5、GATA4和α-MHC.试验结果表明,从人羊水标本中可分离得到具有胚胎干细胞特性的细胞,经初步检测确定为羊水干细胞,并能通过形成类胚体诱导其向心肌细胞分化.  相似文献   
210.
Guo F  Zhou Z  Dou Y  Tang J  Gao C  Huan J 《Cytokine》2012,57(3):417-428
The purpose of study is to investigate the effects of GEF-H1/RhoA pathway in regulating intercellular adhesion molecule-1 (ICAM-1) expression in lipopolysaccharide (LPS)-activated endothelial cells. Exposure of human umbilical vein endothelial cells (HUVECs) to LPS induced GEF-H1 and ICAM-1 expression in dose- and time-dependent up-regulating manners. Pretreatment with Clostridium difficile toxin B-10463 (TcdB-10463), an inhibitor of Rho activity, reduced LPS-related phosphorylation of p65 at Ser 536 in a dose-dependent manner. Inhibition of TLR4 expression significantly blocked LPS-induced RhoA activity, NF-κB transactivation, GEF-H1 and ICAM-1 expression. Coimmunoprecipitation assay indicated that LPS-activated TLR4 and GEF-H1 formed a signalling complex, suggesting that LPS, acting through TLR4, stimulates GEF-H1 expression and RhoA activity, and thereby induces NF-κB transactivation and ICAM-1 gene expression. However, GEF-H1/RhoA regulates LPS-induced NF-κB transactivation and ICAM-1 expression in a MyD88-independent pathway because inhibition of MyD88 expression could not block LPS-induced RhoA activity. Furthermore, pretreatment with Y-27632, an inhibitor of ROCK, significantly reduced LPS-induced p38, ERK1/2 and p65 phosphorylation, indicating that ROCK acts as an upstream effector of p38 and ERK1/2 to promote LPS-induced NF-κB transactivation and ICAM-1 expression. What is more, the p38 inhibitor (SB203580) but not ERK1/2 inhibitor (PD98059) blocked LPS-induce NF-κB transactivation and ICAM-1 expression, which demonstrates that RhoA mediates LPS-induced NF-κB transactivation and ICAM-1 expression dominantly through p38 but not ERK1/2 activation. In summary, our data suggest that LPS-induced ICAM-1 synthesis in HUVECs is regulated by GEF-H1/RhoA-dependent signaling pathway via activation of p38 and NF-κB.  相似文献   
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