Beneficial effects of C-peptide on renal morphology in diabetic rats

The study was undertaken to examine the effects of C-peptide on glomerular volume (V(GLOM)), mesangial matrix synthesis, and degradation in streptozotocin (STZ)-diabetic rats with poor or moderate glycemic control. Series 1 (poor glycemic control) included groups of healthy rats, hyperglycemic rats, diabetic insulin-treated rats and diabetic C-peptide-treated rats. Series 2 (moderate glycemic control) included groups of healthy rats, diabetic insulin-treated rats, diabetic insulin- and C-peptide-treated rats. After 8 weeks, the left kidney was excised for evaluation of V(GLOM) and mesangial matrix area via light microscopy. Mesangial cells were cultured for 48 h and type IV collagen expression and matrix metalloproteinase (MMP)-2 expression were measured by ELISA and RT-PCR. The results indicated that in Series 1, C-peptide administration suppressed the diabetes-induced increase in the V(GLOM) and the mesangial matrix area. In Series 2, C-peptide administration resulted in a similar decrease in the V(GLOM) and a greater decrease in the mesangial matrix area when compared with insulin therapy alone. Moreover, C-peptide (300 nM) completely inhibited the glucose-induced increase of the collagen IV mRNA expression and protein concentration in mesangial cells cultured in 30 mM glucose medium. MMP-2 mRNA expression was not influenced by C-peptide. In conclusion, C-peptide administration to STZ-diabetic rats for 8 weeks results in the inhibition of diabetes-induced expansion of the mesangial matrix. This effect is independent of the level of glycemic control and results from the inhibition of diabetes-induced excessive formation of mesangial type IV collagen.     

蓝莓果渣提取物总酚含量及抗氧化活性研究

研究了蓝莓果渣提取物总酚含量及其抗氧化活性。分别采用水、40%乙醇及纤维素酶辅助乙醇超声提取蓝莓果渣,并用Folin-Ciocalteu试剂对3种提取物的总酚含量进行评估;并采用DPPH清除实验及O2—.清除实验对3种提取物的抗氧化活性进行研究。实验结果表明,纤维素酶辅助超声提取蓝莓果渣的总酚含量最高,可达425.36±15.21 mg GAE.100 g-1DW,远远高于水提物(169.46±9.75 mg GAE.100 g-1DW)及醇提物(218.39±12.54mg GAE.100 g-1DW)中的总酚含量。且纤维素酶辅助乙醇超声提取物对DPPH的清除能力为2.67±0.13 gVc.100 g-1DW,对O—.2的清除能力2.48±0.14 g Vc.100 g-1DW,明显好于醇提物及水提物抗氧化活性。     

The alternative pathway in cucumber seedlings under low temperature stress was enhanced by salicylic acid

The alternative pathway is a cyanide-resistant and non-phosphorylatory electron transport pathway in mitochondria of higher plants. Alternative oxidase (AOX) is the terminal oxidase of this pathway. Our present study investigated the effect of exogenous salicylic acid (SA) on alternative pathway in cucumber (Cucumis sativus L.) seedlings under low temperature stress. Results showed that during the process of low temperature stress, the alternative pathway capacity was enhanced as AOX expression increased in SA pretreated seedlings. Compared with seedlings without SA pretreatment, slower decrease of relative water content and lower levels of electrolyte leakage, H₂O₂ and malonyldialdehyde content were detected in SA pretreated seedlings. These results indicated that SA could alleviate the injury caused by low temperature on cucumber seedlings. Since the special protective functions of alternative pathway and AOX in plants, we suggested that the alternative pathway was related to SA-mediated plant resistance to environmental stresses such as low temperature.     

A phosphoinositide 3-kinase-γ inhibitor, AS605240 prevents bleomycin-induced pulmonary fibrosis in rats

Phosphoinositide 3-kinase-γ (PI3Kγ) has been identified to play the critical roles in inflammatory cells activation and recruitment in multiply inflammatory diseases and it promised to be a prospective target for relevant inflammatory diseases therapy. AS605240, a selective PI3Kγ inhibitor, has been proved effective on several inflammatory diseases. In this study, we investigated the protective effect of AS605240 on bleomycin-induced pulmonary fibrosis in rats. Our results showed that orally administration of AS605240 significantly prevented lung inflammation and reduced collagen deposition. AS605240 also inhibited augmented expression of TNF-α and IL-1β induced by bleomycin instillation. Moreover, the mRNA levels of TNF-α and IL-1β in lung were remarkably suppressed. Histological assessment found that AS605240 reduced the expression of TGF-β₁ and prevented T lymphocytes infiltration to lung. Phospho-Akt level in inflammatory cells by blocking PI3Kγ was down-regulated and the inhibition of Akt phosphorylation was further confirmed by Western blot. Our findings illustrated that AS605240 was effective for preventing pulmonary fibrosis by suppressing inflammatory cells recruitment and production of inflammatory cytokines. These findings also suggest that PI3Kγ may be a useful target in treating inflammation diseases and AS605240 may represent a promising novel agent for the future therapy of pulmonary fibrosis.     

Role of plant dehydrins in antioxidation mechanisms

Plant antioxidation system is composed of a series of complex mechanisms, in which many antioxidants including some special proteins are involved. Dehydrins are a family of late embryogenesis abundant (LEA) proteins which usually accumulate in plants during late embryogenesis or in response to environmental stresses. They were suggested to be associated with specific protective functions in plant cells, such as preventing coagulation of macromolecules and maintaining integrity of crucial cell structures. In recent years, many studies implied that dehydrins also play an antioxidative role to alleviate oxidative damage in stressed plants. They were proposed to scavenge radicals directly and sequester metals which are sources for radical generation to avoid the production of reactive oxygen species (ROS). In this paper, we will discuss the novel putative role of dehydrins in plant antioxidation mechanisms and how dehydrins perform their antioxidative activity.     

角蛋白酶生产菌株的分离筛选与鉴定

【目的】分离筛选具有高效脱毛能力的野生角蛋白酶生产菌株,开发无硫制革生物脱毛剂。【方法】以贮备原料皮的特定环境中的污水样品为菌株源、在含诱导物脱脂羊毛粉的培养基中的富集、筛选与评估其发酵液脱毛能力的多相筛选方法分离选育高产角蛋白酶野生菌株。通过形态学、生理生化特征,Biolog全自动分析以及16SrDNA基因序列分析等方法多尺度地鉴定目的菌株。【结果】定向筛选得到了一株高活力,无硫脱毛效率高的菌株。鉴定结果表明,该菌株为地衣芽孢杆菌属,故命名为地衣芽孢杆菌(Bacillus licheniformis)X-47。【结论】应用多相定位选育技术筛选出的菌株地衣芽孢杆菌(Bacillus licheniformis)X-47,产角蛋白酶活力高,脱毛效率高,对胶原作用力弱的特点,具有开发无硫脱毛生物助剂的潜力。     

Mechanical force affects expression of an in vitro metastasis-like phenotype in HCT-8 cells

Cancer deaths are primarily caused by metastases, not by the parent tumor. During metastasis, malignant cells detach from the parent tumor, and spread through the circulatory system to invade new tissues and organs. The physical-chemical mechanisms and parameters within the cellular microenvironment that initiate the onset of metastasis, however, are not understood. Here we show that human colon carcinoma (HCT-8) cells can exhibit a dissociative, metastasis-like phenotype (MLP) in vitro when cultured on substrates with appropriate mechanical stiffness. This rather remarkable phenotype is observed when HCT-8 cells are cultured on gels with intermediate-stiffness (physiologically relevant 21-47 kPa), but not on very soft (1 kPa) and very stiff (3.6 GPa) substrates. The cell-cell adhesion molecule E-Cadherin, a metastasis hallmark, decreases 4.73 ± 1.43 times on cell membranes in concert with disassociation. Both specific and nonspecific cell adhesion decrease once the cells have disassociated. After reculturing the disassociated cells on fresh substrates, they retain the disassociated phenotype regardless of substrate stiffness. Inducing E-Cadherin overexpression in MLP cells only partially reverses the MLP phenotype in a minority population of the dissociated cells. This important experiment reveals that E-Cadherin does not play a significant role in the upstream regulation of the mechanosensing cascade. Our results indicate, during culture on the appropriate mechanical microenvironment, HCT-8 cells undergo a stable cell-state transition with increased in vitro metastasis-like characteristics as compared to parent cells grown on standard, very stiff tissue culture dishes. Nuclear staining reveals that a large nuclear deformation (major/minor axis ratio, 2:5) occurs in HCT-8 cells when cells are cultured on polystyrene substrates, but it is markedly reduced (ratio, 1:3) in cells grown on 21 kPa substrates, suggesting the cells are experiencing different intracellular forces when grown on stiff as compared to soft substrates. Furthermore, MLP can be inhibited by blebbistatin, which inactivates myosin II activity and relaxes intracellular forces. This novel finding suggests that the onset of metastasis may, in part, be linked to the intracellular forces and the mechanical microenvironment of the tumor.     

Activation of gibberellin 2-oxidase 6 decreases active gibberellin levels and creates a dominant semi-dwarf phenotype in rice （Oryza sativa L.）

Gibberellin (GA) 2-oxidase plays a key role in the GA catabolic pathway through 2β-hydroxylation.In the present study,we isolated a CaMV 35S-enhancer activation tagged mutant,H032.This mutant exhibited a dominant dwarf and GA-deficient phenotype,with a final stature that was less than half of its wild-type counterpart.The endogenous bioactive GAs are markedly decreased in the H032 mutant,and application of bioactive GAs (GA3 or GA4) can reverse the dwarf phenotype.The integrated T-DNA was detected 12.8 kb upstream of the OsGA2ox6 in the H032 genome by TAIL-PCR.An increased level of OsGA2ox6 mRNA was detected at a high level in the H032 mutant,which might be due to the enhancer role of the CaMV 35S promoter.RNAi and ectopic expression analysis of OsGA2ox6 indicated that the dwarf trait and the decreased levels of bioactive GAs in the H032 mutant were a result of the up-regulation of the OsGA2ox6 gene.BLASTP analysis revealed that OsGA2ox6 belongs to the class III of GA 2-oxidases,which is a novel type of GA2ox that uses C20-GAs (GA12 and/or GA53) as the substrates.Interestingly,we found that a GA biosynthesis inhibitor,paclobutrazol,positively regulated the OsGA2ox6 gene.Unlike the over-expression of OsGA2ox1,which led to a high rate of seed abortion,the H032 mutant retained normal flowering and seed production.These results indicate that OsGA2ox6 mainly affects plant stature,and the dominant dwarf trait of the H032 mutant can be used as an efficient dwarf resource in rice breeding.