ABSTRACT
@#Abstract: Mosquitoes are involved in the transmission of serious diseases such as malaria, dengue, chikungunya, yellow fever, Zika virus disease, and filariasis, and their prevention and control have always been a research hotspot. Currently, mosquito control methods mainly include physical control, chemical control and biological control. Physical control methods are environmentally friendly, but they are slow to take effect and have unsatisfactory control effects; although chemical control can quickly eliminate mosquitoes, it has been eliminated due to its high pollution, high residual, and easy drug resistance; biological control uses natural enemies or pathogens to kill mosquitoes and reduce their ability to transmit disease. Therefore, environmentally friendly biological control has become the main measure for controlling and preventing mosquitoes. In recent years, significant progress has been made in bacterial mosquito control agents, among which Bacillus thuringiensis has been the most extensively studied. Bacillus thuringiensis is a Gram-positive soil microorganism, which is the pathogenic bacterium of a variety of agricultural pests such as Lepidoptera, Coleoptera and Diptera. During the sporulation process, its strains produce a variety of insecticidal crystal proteins (ICPs) or δ-endotoxins with insecticidal activity against mosquito larvae. This review firstly introduces the crystal proteins of Bacillus thuringiensis, describes in detail the types and structures of crystal proteins in detail, and also reveals the mechanism of action of crystal proteins related to receptors.
ABSTRACT
The anti-inflammatory and antibacterial mechanisms of bone marrow mesenchymal stem cells (MSCs) ameliorating lung injury in chronic obstructive pulmonary disease (COPD) mice induced by cigarette smoke and Haemophilus Parainfluenza (HPi) were studied.The experiment was divided into four groups in vivo:control group,COPD group,COPD+HPi group,and COPD+HPi+MSCs group.The indexes of emphysematous changes,inflammatory reaction and lung injury score,and antibacterial effects were evaluated in all groups.As compared with control group,emphysematous changes were significantly aggravated in COPD group,COPD+HPi group and COPD+HPi+MSCs group (P＜0.01),the expression of necrosis factor-kappaB (NF-κB) signal pathway and proinflammatory cytokines in bronchoalveolar lavage fluid (BALF) were increased (P＜0.01),and the phagocytic activity of alveolar macrophages was downregulated (P＜0.01).As compared with COPD group,lung injury score,inflammatory cells and proinflammatory cytokines were significantly increased in the BALF of COPD+HPi group and COPD+HPi+MSCs group (P＜0.01).As compared with COPD+HPi group,the expression of tumor necrosis factor-α stimulated protein/gene 6 (TSG-6) was increased,the NF-κB signal pathway was depressed,proinflammatory cytokine was significantly reduced,the anti-inflammatory cytokine IL-10 was increased,and lung injury score was significantly reduced in COPD+HPi+MSCs group.Meanwhile,the phagocytic activity of alveolar macrophages was significantly enhanced and bacterial counts in the lung were decreased.The results indicated cigarette smoke caused emphysematous changes in mice and the phagocytic activity of alveolar macrophages was decreased.The lung injury of acute exacerbation of COPD mice induced by cigarette smoke and HPi was alleviated through MSCs transplantation,which may be attributed to the fact that MSCs could promote macrophages into anti-inflammatory phenotype through secreting TSG-6,inhibit NF-κB signaling pathway,and reduce inflammatory response through reducing proinflammatory cytokines and promoting the expression of the anti-inflammatory cytokine.Simultaneously,MSCs could enhance phagocytic activity of macrophages and bacterial clearance.Meanwhile,we detected anti-inflammatory and antibacterial activity of macrophages regulated by MSCs in vitro.As compared with RAW264.7+HPi+CSE group,the expression of NF-κB p65,IL-1β,IL-6 and TNF-α was significantly reduced,and the phagocytic activity of macrophages was significantly increased in RAW264.7+HPi+CSE+MSCs group (P＜0.01).The result indicated the macrophages co-cultured with MSCs may inhibit NF-κB signaling pathway and promote phagocytosis by paracrine mechanism.