Oxazolone-induced over-expression of focal adhesion kinase in colonic epithelial cells of colitis mouse model

We examined the change of protein tyrosine kinases (PTKs) expression levels in colonic epithelial cells isolated from mice in which colitis was induced by oxazolone administration, using the monoclonal antibody YK34, which cross-reacts with a wide variety of PTKs. We identified focal adhesion kinase (FAK) and found the expression level increased due to the induction of colitis. Furthermore, we found that there was a positive correlation between FAK expression and the severity of colitis. Also, FAK expression localized in the colonic epithelium but not in the lamina propria, implying FAK functions in epithelial cells during colitis formation and/or wound repairing.     

Spatial and temporal variation of fish assemblages in a subtropical small stream of the Huangshan Mountain

Spatial and temporal variation of fish assemblages were investigated seasonally from May 2007 to February 2008 across 11 study sites in a subtropical small stream, the Puxi Stream, of the Huangshan Mountain. Along the longitudinal gradient from headwater to downstream, fish species richness and abundance increased gradually, but then decreased significantly at the lower reaches. The highest species richness and abundance were observed in August and the lowest in February. Based on analysis of similarities (...     

鸡β-防御素-1真核表达载体构建及其在Flp-In-293细胞中的表达

以防御素为研究对象探讨其药用开发价值已是国内外生物医学研究领域的热点之一,鸡β-防御素-1 (Gallinacin-1,Gal-1)对许多致病菌都具有杀菌作用,具有很好的研究开发价值.本研究以含有Gal-1成熟肽全长cDNA的重组质粒pMD19-T-Gal-1为模板,通过PCR在Gal-1成熟肽基因C末端引入6×His-tag,并将其克隆到pcDNA3.1 (+)载体中,构建真核表达质粒pcDNA3.1 (+)-Gal-1-His;经脂质体介导转染Flp-In-293细胞,48 h后间接免疫荧光分析,结果重组质粒pcDNA3.1 (+)-Gal-1-His转染的Flp-In-293细胞中有绿色荧光,而阴性对照中无荧光,表明Gal-1-His在Flp-In-293细胞中得到了表达.本研究结果将为进一步研究Gal-1的功能奠定基础.     

Pre-cold acclimation improves the immune function of trachea and resistance to cold stress in broilers

Acclimation can alleviate the damage caused by adverse environmental factors. To investigate the effects of cold stimulation on immunity in tracheal of broilers, 360 one-day-old chicks were raised at normal temperatures during 1–7 days. From 8 day, G1 (control) continued to be raised at normal temperatures, whereas G2 and G3 (treatment groups) were cold-stimulated at 3°C and 12°C below the temperature of G1, respectively. At 42 day, all the groups were subjected to a 24-hr acute cold stress, designated as S1, S2, and S3. Tracheal tissues were collected to detect gene levels of immunoglobulins, antimicrobial peptides, Hsps, and cytokines, and oxidative stress-related indicators at 14 day, 42 day, and 43 day, and protein levels of Hsps and proinflammatory cytokines as well as morphology changes at 42 day and 43 day. The results showed that, compared with 42G1, tracheal structure of 42G2 was basically intact, and gene levels of immunoglobulins and antimicrobial peptides increased (p < 0.05), whereas tracheal structure of 42G3 was destroyed, with decreased levels of immunoglobulins ( p < 0.05), and increased levels of Hsps and proinflammatory cytokines ( p < 0.05). At 43 day, tracheal damage was visible and gene levels of immunoglobulins and antimicrobial peptides decreased in S1 ( p < 0.05). Tracheal structure was relatively intact and gene levels of antimicrobial peptides increased in S2 ( p < 0.05). Compared with S1 and S3, immune-related gene levels in S2 were higher, and Hsps and proinflammatory cytokines levels were lower. The results demonstrate that cold stimulation of lower 3°C from 8 to 42 day led to cold acclimation, which improved immunity of tracheal mucosa and resistance to cold stress in broilers.     

Focal adhesion kinase regulates intestinal epithelial barrier function via redistribution of tight junction

Disruption of epithelial barrier function was identified as one of the pathologic mechanisms in inflammatory bowel diseases (IBD). Epithelial barrier consists of various intercellular junctions, in which the tight junction (TJ) is an important component. However, the regulatory mechanism of tight junction is still not clear. Here we examined the role of focal adhesion kinase (FAK) in the epithelial barrier function on Caco-2 monolayers using a specific FAK inhibitor, PF-573, 228 (PF-228). We found that the decrease of transepithelial resistance and the increase of paracellular permeability were accompanied with the inhibition of autophosphorylation of FAK by PF-228 treatment. In addition, PF-228 inhibited the FAK phosphorylation at Y576/577 on activation loop by Src, suggesting Src-dependent regulation of FAK in Caco-2 monolayers. In an ethanol-induced barrier injury model, PF-228 treatment also inhibited the recovery of transepithelial resistance as well as these phosphorylations of FAK. In a sucrose gradient ultracentrifugation, FAK co-localized with claudin-1, an element of the TJ complex, and they co-migrate after ethanol-induced barrier injury. Immunofluorescence imaging analysis revealed that PF-228 inhibited the FAK redistribution to the cell border and reassembly of TJ proteins in the recovery after ethanol-induced barrier injury. Finally, knockdown of FAK by siRNA resulted in the decrease of transepithelial resistance. These findings reveal that activation of FAK is necessary for maintaining and repairing epithelial barrier in Caco-2 cell monolayer via regulating TJ redistribution.     

Extraction, purification and antitumor activity of a water-soluble polysaccharide from the roots of Polygala tenuifolia

One polysaccharide PTP was isolated and purified from the roots of Polygala tenuifolia. It consisted of galactose, glucose and galactose in the ratio of 3.1:3.7:2.5, and a small amount of rhamnose, mannose and xylose. 17 general amino acids were identified to be components of the protein-bound polysaccharide analyzed by automatic amino acid analyzer. In order to test the anti-cancer activity of PTP, we investigated its effect against the growth of human ovarian cancer cells SKOV3 in vitro and in ovarian cancer rats. The intracellular reactive oxygen species (ROS) and glutathione (GSH) in SKOV3 cells following PTP treatment were also quantified to explore the possible mechanism underlying the antitumor activity of the polysaccharide. The result showed that PTP is effective on inhibiting the proliferation of SKOV3 cells in a concentration-dependent manner. Furthermore, treatment with PTP caused a rapid depletion of intracellular GSH content and accumulation of intracellular ROS, thus resulting in the apoptosis, which may prove to be a pivotal mechanism for its cancer protection action. In addition, a significant tumor growth inhibition effect was observed in nude mice after PTP administration for 7 weeks. All above indicated PTP could be beneficial towards ovarian cancer therapy.