Adsorption of DNA by Bacteria and Their Composites with Minerals

Previous studies revealed the thermodynamic properties of DNA adsorption on pure minerals or biomasses; however, there has been little attempt to develop such studies on bacteria–mineral composites. Equilibrium adsorption experiments, attenuated total reflectance Fourier transform infrared spectroscopy, and isothermal titration calorimetry were employed to investigate the adsorption of DNA by Bacillus subtilis, Pseudomonas putida, and their composites with minerals. Similar capacity and affinity were observed for DNA adsorption on two bacterial cells. However, different patterns were found in the adsorption of DNA by bacteria–mineral composites. The Gram-positive bacterium B. subtilis enhanced the adsorption of DNA on its mineral composites compared with their individual components, while the composites of Gram-negative bacterial cells with kaolinite and goethite bound lower amounts of DNA than the predicted values. The thermodynamic parameters and the Fourier transform infrared spectra showed that van der Waals force and hydrogen bonding are responsible for the DNA adsorption on B. subtilis–minerals and P. putida–kaolinite. By contrast, the entropy increases of excluded water rearrangement and dehydration effect play key roles in the interaction between DNA and P. putida–montmorillonite/goethite composites.     

Extracellular vesicles in bone and tooth: A state-of-art paradigm in skeletal regeneration

Bone and tooth, fundamental parts of the craniofacial skeleton, are anatomically and developmentally interconnected structures. Notably, pathological processes in these tissues underwent together and progressed in multilevels. Extracellular vesicles (EVs) are cell-released small organelles and transfer proteins and genetic information into cells and tissues. Although EVs have been identified in bone and tooth, particularly EVs have been identified in the bone formation and resorption, the concrete roles of EVs in bone and tooth development and diseases remain elusive. As such, we review the recent progress of EVs in bone and tooth to highlight the novel findings of EVs in cellular communication, tissue homeostasis, and interventions. This will enhance our comprehension on the skeletal biology and shed new light on the modulation of skeletal disorders and the potential of genetic treatment.     

Functional analysis of a miRNA‐like small RNA derived from Bombyx mori cytoplasmic polyhedrosis virus

Bombyx mori cytoplasmic polyhedrosis virus (BmCPV) is a major pathogen of the economic insect silkworm, Bombyx mori. Virus‐encoded microRNAs (miRNAs) have been proven to play important roles in host–pathogen interactions. In this study we identified a BmCPV‐derived miRNA‐like 21 nt small RNA, BmCPV‐miR‐1, from the small RNA deep sequencing of BmCPV‐infected silkworm larvae by stem‐loop quantitative real‐time PCR (qPCR) and investigated its functions with qPCR and lentiviral expression systems. Bombyx mori inhibitor of apoptosis protein (BmIAP) gene was predicted by both target prediction software miRanda and Targetscan to be one of its target genes with a binding site for BmCPV‐miR‐1 at the 5′ untranslated region. It was found that the expression of BmCPV‐miR‐1 and its target gene BmIAP were both up‐regulated in BmCPV‐infected larvae. At the same time, it was confirmed that BmCPV‐miR‐1 could up‐regulate the expression of BmIAP gene in HEK293T cells with lentiviral expression systems and in BmN cells by transfecting mimics. Furthermore, BmCPV‐miR‐1 mimics could up‐regulate the expression level of BmIAP gene in midgut and fat body in the silkworm. In the midgut of BmCPV‐infected larvae, BmCPV‐miR‐1 mimics could be further up‐regulated and inhibitors could lower the virus‐mediated expression of BmIAP gene. With the viral genomic RNA segments S1 and S10 as indicators, BmCPV‐miR‐1 mimics could up‐regulate and inhibitors down‐regulate their replication in the infected silkworm. These results implied that BmCPV‐miR‐1 could inhibit cell apoptosis in the infected silkworm through up‐regulating BmIAP expression, providing the virus with a better cell circumstance for its replication.     

H.pylori可塑区tfs3a分泌系统virB2基因功能

目的对virB2基因编码蛋白进行分析,为virB2基因及其编码蛋白功能提供实验依据。方法利用多种生物学软件以及网站对VirB2蛋白的结构和功能进行分析预测,VirB2蛋白序列通过基因推导获得并由生物公司合成,然后通过免疫动物实验制备鼠抗VirB2蛋白多克隆抗体,同时设计进行VirB2蛋白细胞毒试验(MTT法)。结果virB2基因编码蛋白属于疏水性蛋白,为鞭毛样结构,有较强的细胞毒作用。结论对VirB2蛋白的结构和功能进行了分析预测,证明VirB2蛋白在H.pylori相关的致病性特别是引起胃黏膜炎症方面起到一定的作用,能够为研究H.pylori致病机制提供帮助。     

Recruitment of Nox4 to a Plasma Membrane Scaffold Is Required for Localized Reactive Oxygen Species Generation and Sustained Src Activation in Response to Insulin-like Growth Factor-I

Nox4-derived ROS is increased in response to hyperglycemia and is required for IGF-I-stimulated Src activation. This study was undertaken to determine the mechanism by which Nox4 mediates sustained Src activation. IGF-I stimulated sustained Src activation, which occurred primarily on the SHPS-1 scaffold protein. In vitro oxidation experiments indicated that Nox4-derived ROS was able to oxidize Src when they are in close proximity, and Src oxidation leads to its activation. Therefore we hypothesized that Nox4 recruitment to the plasma membrane scaffold SHPS-1 allowed localized ROS generation to mediate sustained Src oxidation and activation. To determine the mechanism of Nox4 recruitment, we analyzed the role of Grb2, a component of the SHPS-1 signaling complex. We determined that Nox4 Tyr-491 was phosphorylated after IGF-I stimulation and was responsible for Nox4 binding to the SH2 domain of Grb2. Overexpression of a Nox4 mutant, Y491F, prevented Nox4/Grb2 association. Importantly, it also prevented Nox4 recruitment to SHPS-1. The role of Grb2 was confirmed using a Pyk2 Y881F mutant, which blocked Grb2 recruitment to SHPS-1. Cells expressing this mutant had impaired Nox4 recruitment to SHPS-1. IGF-I-stimulated downstream signaling and biological actions were also significantly impaired in Nox4 Y491F-overexpressing cells. Disruption of Nox4 recruitment to SHPS-1 in aorta from diabetic mice inhibited IGF-I-stimulated Src oxidation and activation as well as cell proliferation. These findings provide insight into the mechanism by which localized Nox4-derived ROS regulates the sustained activity of a tyrosine kinase that is critical for mediating signal transduction and biological actions.     

Dissipative particle dynamics simulation of a gold nanoparticle system

Dissipative particle dynamics (DPD) was carried out to study systems containing gold atoms, organic ether (oligohydroquinonyl ether terminated with a thiol group) and organic solvents. The components in the simulated system are very different in size and chemical nature. Our simulation showed that the reproduction of the macroscopic experimental phase separation, properly dividing the polymeric molecule into beads, selecting the size of gold bead, and choosing the appropriate interaction parameters between beads are crucial. In addition, the solvent effect was the dominant factor for the formation of spherical aggregates of Au atoms and organic ether molecules. We report the interaction strengths between the solvent and gold clusters. Our work has demonstrated that DPD methods can be applied to the study of complex meso-scale systems.     

感染环形泰勒焦虫(Theileria annulata)的牛外周血白细胞的形态观察

用光镜及扫描电镜观察了体外高代培养的含牛焦虫颗粒的牛外周血白细胞的形态及在细胞周期中细胞表面的特征性变化。这种经多年传代的含虫的牛外周血白细胞恢复了分裂和繁殖的能力,目前已成为较稳定的细胞系。细胞表面具多种伪足突起,如叶状、丝状及绒毛状。细胞周期中备期细胞表面的主要特征是:S期:细胞平扁,边缘具薄的时状伪足及丝状伪足;G_2期:细胞中部隆起,表面具少量绒毛状伪足;G_1期:绒毛状结构少或无,而出现丝状及小的叶状伪足,细胞仍保持球形;M期:细胞球形,表面密被以绒毛。作者根据扫描电镜的观察认为光镜下所观察的两类细胞,实际上是反映了一种细胞处于不同发育阶段时的特征。     

A review of the distribution of all species of deer (Tragulidae, Moschidae and Cervidae) in China

Twenty-one species of deer occur in China: one species of Tragulidae, three species of Moschidae and 17 species of Cervidae. The foundation of this review is the research conducted in the early 1940s by Allen, combined with the research and investigation by the authors and other Chinese specialists since that time. This paper focuses on the tentative distribution of these species of deer for future research efforts.