没食子酸对水稻细菌性条斑病菌细胞结构的影响

没食子酸(gallic acid, GA)是一种植物酚类化合物,具有多种生物活性。前期实验发现,GA对水稻细菌性条斑病菌(Xanthomonas oryzae pv. oryzicola, Xoc)具有较强的抑制作用。为了解该物质对Xoc的细胞结构和细胞膜的影响,该研究用电子显微镜观察GA对Xoc的形态结构的影响,通过测定GA处理后的Xoc培养液的电导率、紫外吸收物含量(260 nm的吸光值)、乳酸脱氢酶的活性以及菌体的二乙酸荧光素(fluorescein diacetate, FDA)的强度等,探讨了GA对Xoc细胞膜的完整性和通透性的影响。结果表明:经浓度为200 μg·mL^-1的 GA处理后,Xoc的菌体形态结构发生改变,表面有明显的凹陷或不规则囊泡状突起,表明GA对Xoc细胞壁有损伤作用。200 μg·mL^-1的GA处理24 h后,病菌培养液的电导率为135.48 μS·cm^-1(对照处理为127.85 μS·cm^-1)。GA处理2 h后,Xoc细胞荧光强度下降58.10%,说明病菌细胞内电解质外渗和细胞溶质发生渗漏; 同时,乳酸脱氢酶的活性增加,表明菌体的细胞膜受到破坏。此外,GA处理24 h后,Xoc培养液在260 nm下的吸光值为1.004(对照处理为0.018),表明病菌细胞膜的完整性受到破坏。这表明GA不仅破坏Xoc的细胞膜通透性,而且还影响膜的完整性。     

Gadoxetic Acid Disodium-Enhanced Magnetic Resonance Imaging for the Detection of Hepatocellular Carcinoma: A Meta-Analysis

Objective

To determine the accuracy of MR imaging with gadoxetic acid disodium (Gd-EOB-DTPA) for the detection of hepatocelluar carcinoma (HCC).

Materials and Methods

A systematic search was performed in PUBMED, EMBASE, Web of Science, Cochrane Library and the Chinese Biomedical Literature Database up to March 2013 to identify studies about evaluation of Gd-EOB-DTPA enhanced MR imaging in patients suspected of having HCC. The data were extracted to perform heterogeneity test and threshold effect test and to calculate sensitivity, specificity, diagnostic odds ratio, predictive value, and areas under summary receiver operating characteristic curve (AUC).

Results

From 601 citations, 10 were included in the meta-analysis. The methodological quality of the 10 studies was good. Overall HCC: There was significant heterogeneity in the pooled analysis (I² = 69.4%, P = 0.0005), and the pooled weighted values were determined to be sensitivity: 0.91 (95% confidence interval (CI): 0.89, 0. 93); specificity: 0.95 (95% CI: 0.94, 0.96); diagnostic odds ratio: 169.94 (95% CI: 108.84, 265.36); positive likelihood ratio: 15.75 (95% CI: 7.45, 33.31); negative likelihood ratio: 0.10 (95% CI: 0.06, 0.15). The AUC was 0.9778. HCC in cirrhosis: The estimates were to be sensitivity: 0.91 (95% CI: 0.88, 0.93); specificity: 0.93 (95% CI: 0.89, 0.95); diagnostic odds ratio: 234.24 (95% CI: 33.47, 1639.25); positive likelihood ratio: 15.08 (95% CI: 2.20, 103.40); negative likelihood ratio: 0.08 (95% CI: 0.03, 0.21). The AUC was 0.9814. ≤20 mm HCC: The AUC was 0.9936. There was no notable publication bias.

Conclusions

This meta-analysis suggests that MR imaging with Gd-EOB-DTPA has high diagnostic accuracy for the detection of HCC, especially for ≤20 mm HCC. This technique shows good prospect in diagnosis of HCC.     

Periodontal ligament-associated protein-1 knockout mice regulate the differentiation of osteoclasts and osteoblasts through TGF-β1/Smad signaling pathway

It has been known that periodontal ligament-associated protein-1 (PLAP-1/Asporin) not only inhibits cartilage formation in osteoarthritis, but it also influences the healing of skull defect. However, the effect and mechanism of PLAP-1/Asporin on the mutual regulation of osteoclasts and osteoblasts in periodontitis are not clear. In this study, we utilized a PLAP-1/Asporin gene knockout (KO) mouse model to research this unknown issue. We cultured mouse bone marrow mesenchymal stem cells with Porphyromonas gingivalis lipopolysaccharide (P.g. LPS) for osteogenic induction in vitro. The molecular mechanism of PLAP-1/Asporin in the regulation of osteoblasts was detected by immunoprecipitation, immunofluorescence, and inhibitors of signaling pathways. The results showed that the KO of PLAP-1/Asporin promoted osteogenic differentiation through transforming growth factor beta 1 (TGF-β1)/Smad3 in inflammatory environments. We further found the KO of PLAP-1/Asporin inhibited osteoclast differentiation and promoted osteogenic differentiation through the TGF-β1/Smad signaling pathway in an inflammatory coculture system. The experimental periodontitis model was established by silk ligation and the alveolar bone formation in PLAP-1/Asporin KO mice was promoted through TGF-β1/Smad3 signaling pathway. The subcutaneous osteogenesis model in nude mice also confirmed that the KO of PLAP-1/Asporin promoted bone formation by the histochemical staining. In conclusion, PLAP-1/Asporin regulated the differentiation of osteoclasts and osteoblasts through TGF-β1/Smad signaling pathway. The results of this study lay a theoretical foundation for the further study of the pathological mechanism underlying alveolar bone resorption, and the prevention and treatment of periodontitis.     

Biological nascent evolution of snail bone and collagen revealed by nonlinear optical microscopy

Using nonlinear optical microscopy of coherent antistokes Raman scattering (CARS), second harmonic generation (SHG) and two‐photo excitation fluorescence, we in situ observed how the collagen and the bone grow synergistically and competitively during nascent biological evolution. The and ions were first observed to be dispersed in the liquid environment, and the collagen was observed 2 days later. With the help of the collagen, the and ions gradually moved closer to the collagen, and then the bone was produced in the forms of CaCO₃ and CaPO₃. When the bone was completed with the help of the collagen, the collagen gradually disappeared. The biological evolution of snail bone and collagen can be well revealed by CARS and SHG, and in addition, the biological evolution of structure and morphology can be clearly observed day by day.     

HCV NS3/4A蛋白酶抑制剂细胞筛选模型

丙型肝炎病毒(hepatitis C virus,HCV)持续感染可导致慢性丙型肝炎,并可发展为肝硬化和肝细胞癌。HCV NS3/4A蛋白酶在HCV复制和致病机制中起着非常关键的作用,已成为HCV研究热点。由于候选药物分子必须具有易进入细胞、稳定性好等特征,建立一种细胞水平上酶活性的测定系统对于筛选抗NS3/4A药物无疑有着重要意义。目前已有多种NS3/4A蛋白酶筛选系统开发出来,本文将对此作一综述。     

Cyclophilin a increases CD68<Superscript>+</Superscript> cell infiltration in rat experimental periodontitis

Cyclophilin A (CyPA) is a potent chemokine, which can directly induce leukocyte chemotaxis and contribute to the pathogenesis of inflammation-mediated diseases. This study is to observe the expression and distribution of CyPA and CD68⁺ cells in the histopathogenesis of rat ligation-induced experimental periodontitis, and assess the role of CyPA in CD68⁺ cell infiltration in rat experimental periodontitis. Experimental periodontitis was induced by ligation according to our previous method. CyPA expression in gingival tissues was detected by western blotting. Immunohistochemistry was applied for CyPA and CD68 distribution. For further certifying the role of CyPA in CD68⁺ cell infiltration, the right mandibular first molar received 0.1 μM CyPA locally by gingival injection every 2 days (L?+?C group), while the left mandibular first molar received saline as a control group (L group). The number of CD68⁺ cells in the experimental periodontitis was observed by immunohistochemistry. Alveolar bone destruction was assessed by micro-computerized tomography (micro-CT). Osteoclast was observed through TRAP staining. Nuclear factor (NF)-κB phospho-p65 (p p65) and phosphor-IκBα (p IκBα) expressions were detected to investigate NF-κB activation. CyPA showed an increasing trend at 1–6 weeks after ligation. CyPA and CD68⁺ cells were present in the gingival inflammatory infiltration, and participated in alveolar bone destruction. In the L?+?C group, the number of CD68⁺ cells was increased compared with the L group, and greater alveolar bone destruction was observed. NF-κB p p65 and p IκBα expressions were upregulated in the L?+?C group compared with the L group indicating NF-κB activation. CyPA increases CD68⁺ cell infiltration in rat experimental periodontitis, suggesting CyPA might be an anti-inflammatory therapeutic target.     

An inference of the wading depths of the cranes in wintering wetlands through photographic sampling: a case study of black-necked cranes (Grus nigricollis) in Caohai Wetland,China

Wetlands Ecology and Management - Several overwintering crane species like Black-necked cranes (Grus nigricollis) mainly depends on wetlands for foraging or roosting, preferring stable water...