Porous Tantalum Coatings Prepared by Vacuum Plasma Spraying Enhance BMSCs Osteogenic Differentiation and Bone Regeneration In Vitro and In Vivo

Tantalum, as a potential metallic implant biomaterial, is attracting more and more attention because of its excellent anticorrosion and biocompatibility. However, its significantly high elastic modulus and large mechanical incompatibility with bone tissue make it unsuitable for load-bearing implants. In this study, porous tantalum coatings were first successfully fabricated on titanium substrates by vacuum plasma spraying (VPS), which would exert the excellent biocompatibility of tantalum and alleviate the elastic modulus of tantalum for bone tissue. We evaluated cytocompatibility and osteogenesis activity of the porous tantalum coatings using human bone marrow stromal cells (hBMSCs) and its ability to repair rabbit femur bone defects. The morphology and actin cytoskeletons of hBMSCs were observed via electron microscopy and confocal, and the cell viability, proliferation and osteogenic differentiation potential of hBMSCs were examined quantitatively by PrestoBlue assay, Ki67 immunofluorescence assay, real-time PCR technology and ALP staining. For in vivo detection, the repaired femur were evaluated by histomorphology and double fluorescence labeling 3 months postoperation. Porous tantalum coating surfaces promoted hBMSCs adhesion, proliferation, osteogenesis activity and had better osseointegration and faster new bone formation rate than titanium coating control. Our observation suggested that the porous tantalum coatings had good biocompatibility and could enhance osseoinductivity in vitro and promote new bone formation in vivo. The porous tantalum coatings prepared by VPS is a promising strategy for bone regeneration.     

Potential host fruits for Drosophila suzukii: olfactory and oviposition preferences and suitability for development

Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), the spotted wing drosophila, is a pest endemic to Southeast Asia that invaded the Americas and Europe in 2008. In contrast to most of its congeners, D. suzukii possesses a serrated ovipositor that allows it to lay eggs in unwounded commercial fruits, resulting in severe revenue losses for the industry. The purpose of this study was to determine the susceptibility of known host fruits, including cherry, strawberry, blueberry, and grape, and potential host fruits, such as banana and apple, to attack by D. suzukii. Based on the responses to volatile cues offered in a six‐choice olfactometer, the preference of female D. suzukii was ranked in the following order: strawberry = cherry > banana = apple = blueberry = grape, but in no‐choice and choice oviposition tests, the preferences were ranked as follows: cherry > strawberry = blueberry > grape = banana > apple. Furthermore, we reconfirmed that D. suzukii mainly targets rotten fruit for feeding and ripe fruit for oviposition, and females preferred fruits with intensive mechanical damage. Based on developmental parameters, apple was the least suitable host. This study has implications for the control of D. suzukii, especially in mixed fruit orchards, by providing a promising avenue for exploiting behaviour‐based control tools and emphasizing the importance of phenology in host fruit susceptibility.     

The stability of impulsive stochastic Cohen–Grossberg neural networks with mixed delays and reaction–diffusion terms

The global asymptotic stability of impulsive stochastic Cohen–Grossberg neural networks with mixed delays and reaction–diffusion terms is investigated. Under some suitable assumptions and using Lyapunov–Krasovskii functional method, we apply the linear matrix inequality technique to propose some new sufficient conditions for the global asymptotic stability of the addressed model in the stochastic sense. The mixed time delays comprise both the time-varying and continuously distributed delays. The effectiveness of the theoretical result is illustrated by a numerical example.     

Stability of delayed memristive neural networks with time-varying impulses

This paper addresses the stability problem on the memristive neural networks with time-varying impulses. Based on the memristor theory and neural network theory, the model of the memristor-based neural network is established. Different from the most publications on memristive networks with fixed-time impulse effects, we consider the case of time-varying impulses. Both the destabilizing and stabilizing impulses exist in the model simultaneously. Through controlling the time intervals of the stabilizing and destabilizing impulses, we ensure the effect of the impulses is stabilizing. Several sufficient conditions for the globally exponentially stability of memristive neural networks with time-varying impulses are proposed. The simulation results demonstrate the effectiveness of the theoretical results.     

Chloroquine inhibits cell growth and induces cell death in A549 lung cancer cells

To investigate the effects of chloroquine diphosphate (CQ) on lung cancer cell growth, we treated A549 cells, a lung cancer cell line, with the drug at various concentrations (0.25-128 microM) for 24-72 h. The results showed that, at lower concentrations (from 0.25 to 32 microM), CQ inhibited the growth of A549 cells and, at the same time, it induced vacuolation with increased volume of acidic compartments (VAC). On the other hand, at higher concentrations (64-128 microM), CQ induced apoptosis at 24 h, while its effect of inducing vacuolation declined. The lactate dehydrogenase (LDH) assay showed that with the treatment of CQ 32-64 microM for 72 h or 128 microM for 48 h, CQ induced necrosis of A549 cells. To understand the possible mechanism by which CQ acts in A549 cells, we further incubated the cells with this drug at the concentrations of 32 or 128 microM in the presence of D609, a specific inhibitor of phosphatidylcholine-specific phospholipase C (PC-PLC). The results showed that D609 (50 microM) could inhibit the effects of CQ 32 microM on the viability and VAC, but it could not change the effects of CQ 128 microM on the same. Our data suggested that CQ inhibited A549 lung cancer cell growth at lower concentrations by increasing the volume of lysosomes and that PC-PLC might be involved in this process. The data also indicated that, at higher concentrations, CQ induced apoptosis and necrosis, but at this time its ability to increase the volume of lysosome gradually declined, and PC-PLC might not be implicated in the process.     

miR-146a interacting with lncRNA EPB41L4A-AS1 and lncRNA SNHG7 inhibits proliferation of bone marrow-derived mesenchymal stem cells

Emerging evidence suggests that microRNA plays a pivotal role in cell proliferation. Our previous research has certified that miR-146a attenuates osteoarthritis through the regulation of cartilage homeostasis. However, little information about the function of miR-146a in bone marrow-derived mesenchymal stem cells (BMSCs) proliferation and the underlying mechanism was available. Therefore, this study aims at investigating the role of miR-146a on the proliferation of BMSCs and the possible mechanisms involved. The function of miR-146a on BMSCs proliferation was studied through overexpression and knockdown of miR-146a or the indicated long noncoding RNAs (lncRNAs) in BMSCs and then the proliferation rate of the BMSCs were detected by Cell Counting Kit-8 assay, colony formation assay. Besides, flow cytometry was used to test the cell cycle state of BMSCs modified by overexpression or knockdown of miR-146a or lncRNA EPB41L4A-AS1 (EPB41L4A Antisense RNA 1) and small nucleolar RNA host gene 7 (SNHG7). The expression level of marker genes involved in modulating cell proliferation was evaluated by quantitative polymerase chain reaction and western blot analysis. We discovered that the knockdown of miR-146a significantly promoted BMSCs proliferation. Moreover, miR-146a could bind to and inhibit endogenous expression of EPB41L4A-AS1 and SNHG7. Further study demonstrated that overexpression of EPB41L4A-AS1 and SNHG7 significantly enhanced proliferation of BMSCs. For the first time, we certified that miR-146a suppressed BMSCs proliferation, but EPB41L4A-AS1 and SNHG7 promoted BMSCs proliferation in the present study. Mechanistically, miR-146a significantly inhibited BMSCs proliferation partly through miR-146a/EPB41L4A-AS1 SNHG7/cell proliferation signaling pathway axis.     

Effects of Co-60 radiation on the activities of three main antioxidant enzymes in Bactrocera dorsalis (Hendel) (Diptera: Tephritidae)

Co-60 radiation has been broadly used for pest management because it results in male sterility and a lack of emergence of unparasitized hosts due to oxidative damage. Insect life is significantly affected by abiotic stress factors, including Co-60 radiation. In the present study, we determined the influence of Co-60 radiation on an important pest in southern China, the oriental fruit fly Bactrocera dorsalis (Diptera: Tephritidae). We exposed 30-h-old B. dorsalis eggs to Co-60 radiation at doses of (0, 5, 10, 15, 20, 25, 30, 35, and 40?Gy) and determined the activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX). CAT and POX activity significantly increased in B. dorsalis in the 1st larvae instar after high-intensity radiation doses (25–40?Gy) and played an important role in the antioxidant response to intensive radiation. The activity of POX in B. dorsalis at the 2nd larval instar sharply decreased after different doses of radiation, except for 10 and 40?Gy. Our results demonstrated that Co-60 radiation affected the activity of antioxidant enzymes and disturbed the physiology of B. dorsalis, especially at early stages (the 1st, 2nd larvae instar). These three antioxidant defense enzymes cooperatively play an important role in protecting B. dorsalis from oxidative damage.     

Assembly processes and source tracking of planktonic and benthic bacterial communities in the Yellow River estuary

Estuaries connect rivers with the ocean and are considered transition regions due to the continuous inputs from rivers. Microbiota from different sources converge and undergo succession in these transition regions, but their assembly mechanisms along environmental gradients remain unclear. Here, we found that salinity had a stronger effect on planktonic than on benthic microbial communities, and the dominant planktonic bacteria changed more distinctly than the dominant benthic bacteria with changes in salinity. The planktonic bacteria in the brackish water came mainly from seawater, which was confirmed in the laboratory, whereas the benthic bacteria were weakly affected by salinity, which appeared to be a mixture of the bacteria from riverine and oceanic sediments. Benthic bacterial community assembly in the sediments was mainly controlled by homogeneous selection and almost unaffected by changes in salinity, the dominant assemblage processes for planktonic bacteria changed dramatically along the salinity gradient, from homogeneous selection in freshwater to drift in seawater. Our results highlight that salinity is the key driver of estuarine microbial succession and that salinity is more important in shaping planktonic than benthic bacterial communities in the Yellow River estuary.     

黄色粘球菌基于复杂社会性细胞行为的生物被膜

黄色粘球菌具有多样化的细胞行为,具备典型多细胞水平的社会性特征。其形成的生物被膜是目前认知的最为复杂的单种群细菌生物被膜之一。黄色粘球菌的社会性细胞行为主导了其生物被膜形成过程中的关键环节,包括固体介质表面的细胞运动、群体细胞的捕食、亲缘细胞的识别、子实体的发育、粘孢子的分化以及细胞程序性死亡等行为过程。文中将介绍相关领域的研究进展。