Design and Simulation of Dynamic TDMA Protocol Based on Tactical Internet

Shibai Yin,Yibing Wang,Weixing Wang 한국산학기술학회 2011 SmartCR Vol.1 No.1

Current TDMA (time division multiple access) protocols based on the dynamic time slot allocation scheme involve some information delays because the source nodes can not send messages in time. These delays are caused by booking the time slots of the next frame in the current transmission. A feasible approach to reduce the delays is to allocate time slots in time. This paper presents a new TDMA protocol that can assign time slots according to the request of traffic load at the beginning of the frame by exchanging the control information. We demonstrate the improvements achieved by our scheme via building the hierarchical Tactical Internet models that employ the new TDMA protocol and via discussing energy consumption, throughput and End-to-End delay. Comparing our scheme with those of related works shows that our protocol achieves good network performance and feasibility in the tactical Internet environment. In addition, the detailed design of the proposed protocol and the specific realization of the whole work by using OPNET Modeler Software are also displayed for the freshman as a tutorial.

Detoxified pneumolysin derivative ΔA146Ply inhibits autophagy and induces apoptosis in acute myeloid leukemia cells by activating mTOR signaling

Zhu Tao,Zhang Hong,Li Sijie,Wu Kaifeng,Yin Yibing,Zhang Xuemei 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Leukemia is caused by the malignant clonal expansion of hematopoietic stem cells, and in adults, the most common type of leukemia is acute myeloid leukemia (AML). Autophagy inhibitors are often used in preclinical and clinical models in leukemia therapy. However, clinically available autophagy inhibitors and their efficacy are very limited. More effective and safer autophagy inhibitors are urgently needed for leukemia therapy. In a previous study, we showed that ΔA146Ply, a mutant of pneumolysin that lacks hemolytic activity, inhibited autophagy of triple-negative breast cancer cells by activating mannose receptor (MR) and toll-like receptor 4 (TLR4) and that tumor-bearing mice tolerated ΔA146Ply well. Whether this agent affects AML cells expressing TLR4 and MR and the related mechanisms remain to be determined. In this study, we found that ΔA146Ply inhibited autophagy and induced apoptosis in AML cells. A mechanistic study showed that ΔA146Ply inhibited autophagy by activating mammalian target of rapamycin signaling and induced apoptosis by inhibiting autophagy. ΔA146Ply also inhibited autophagy and induced apoptosis in a mouse model of AML. Furthermore, the combination of ΔA146Ply and chloroquine synergistically inhibited autophagy and induced apoptosis in vitro and in vivo. Overall, this study provides an alternative effective autophagy inhibitor that may be used for leukemia therapy.

Mast Cells Tryptase Promotes Intestinal Fibrosis in Natural Decellularized Intestinal Scaffolds

Wan Jian,Wu Tianqi,Liu Ying,Yang Muqing,Fichna Jakub,Guo Yibing,Yin Lu,Chen Chunqiu 한국조직공학과 재생의학회 2022 조직공학과 재생의학 Vol.19 No.4

BACKGROUND: Standard two-dimensional (2D) culture has confirmed the mechanism of mast cells (MCs) in the pathogenesis of inflammatory bowel disease (IBD), but the regulation of signaling responses of MCs may well differ in three-dimensional (3D) microenvironments. The aim of the study was to develop a 3D culture model based on decellularized intestinal scaffolds (DIS) and verify how MCs influenced fibroblasts phenotype in the 3D model. METHODS: DIS were achieved using the detergent technique and extracellular matrix (ECM) components were verified by histologic analysis, quantification and scanning electron microscope. After human colon fibroblasts recellularized into the scaffolds and activated by MCs tryptase and TGFb1, the changes in genes and signaling pathways during fibroblasts activation in 3D were studied and compared with the changes in 2D cell culture on plastic plates. RESULTS: Decellularization process effectively removed native cell debris while retaining natural ECM components and structure. The engrafted fibroblasts could penetrate into the scaffolds and maintain its phenotype. No matter whether fibroblasts were cultured in 2D or 3D, MCs tryptase and transforming growth factor b1 (TGF-b1) could promote the differentiation of fibroblasts into fibrotic-phenotype myofibroblasts through Akt and Smad2/3 signaling pathways. Furthermore, the pro-collagen1a1 and fibronectin synthesis of myofibroblasts in 3D was higher than in 2D culture. CONCLUSION: Our results demonstrated that the DIS can be used as a bioactive microenvironment for the study of intestinal fibrosis, providing an innovative platform for future intestinal disease modeling and screening of genes and signaling pathways.

Screening and Identification of ClpE Interaction Proteins in Streptococcus pneumoniae by a Bacterial Two-Hybrid System and Co-immunoprecipitation

WenJuan Yan,YingYing Cai,Qun Zhang,YuSi Liu,WenChun Xu,YiBing Yin,YuJuan He,Hong Wang,XueMei Zhang 한국미생물학회 2013 The journal of microbiology Vol.51 No.4

Hsp100/Clp proteins have crucial functions in the protein quality control, stress tolerance, and virulence of many pathogenic bacteria. ClpE is an important virulence factor involved in adherence and invasion in Streptococcus pneumoniae. To explore the underlying mechanism, we screened ClpE interaction proteins using a bacterial two-hybrid system and co-immunoprecipitation. We used ClpE as bait and constructed the pBT-ClpE bait plasmid for two-hybrid screening. Then, we constructed ClpE::GFP fusion for co-immunoprecipitation screening using anti-GFP monoclonal antibody. We obtained eight potential ClpE interaction proteins,including carbamoyl-phosphate synthase, pyruvate oxidase (SpxB), phosphoenolpyruvate-protein phosphotransferase,aminopeptidase N (pepN), L-lactate dehydrogenase, ribosomal protein S4, sensor histidine kinase (SPD_2019), and FtsW (a cell division protein). FtsW, SpxB, pepN, and SPD_2019 were confirmed to interact with ClpE using Bacterial Two-hybrid or Co-immunoprecipitation. Morphologic observations found that ΔclpE strain existed in abnormal division. β-Galactosidase activity assay suggested that ClpE contributed to the degradation of FtsW. Furthermore, FtsW could be induced by heat shock. The results suggested that ClpE might affect cell division by regulating the level of FtsW. These data may provide new insights in studying the role of ClpE in S. pneumoniae.

Serotype-Independent Protection against Pneumococcal Infections Elicited by Intranasal Immunization with Ethanol-Killed Pneumococcal Strain, SPY1

XiuYu Xu,Qun Zhang,Jiangping Meng,Yiping Wang,Jie Zheng,Kaifeng Wu,Xuemei Zhang,Yibing Yin 한국미생물학회 2014 The journal of microbiology Vol.52 No.4

The 23-valent polysaccharide vaccine and the 7-valent pneumococcalconjugate vaccine are licensed vaccines that protectagainst pneumococcal infections worldwide. However,the incidence of pneumococcal diseases remains high in lowincomecountries. Whole-cell vaccines with high safety andstrong immunogenicity may be a favorable choice. We previouslyobtained a capsule-deficient Streptococcus pneumoniaemutant named SPY1 derived from strain D39. As anattenuated live pneumococcal vaccine, intranasal immunizationwith SPY1 elicits broad serotype-independent protectionagainst pneumococcal infection. In this study, forsafety consideration, we inactivated SPY1 with 70% ethanoland intranasally immunized BALB/c mice with killed SPY1plus cholera toxin adjuvant for four times. Results showedthat intranasal immunization with inactivated SPY1 inducedstrong humoral and cellular immune responses. Intranasalimmunization with inactivated SPY1 plus cholera toxin adjuvantelicited effective serotype-independent protection againstthe colonization of pneumococcal strains 19F and 4 as well aslethal infection of pneumococcal serotypes 2, 3, 14, and 6B. The protection rates provided by inactivated SPY1 againstlethal pneumococcal infection were comparable to those ofcurrently used polysaccharide vaccines. In addition, vaccinespecificB-cell and T-cell immune responses mediated theprotection elicited by SPY1. In conclusion, the 70% ethanolinactivatedpneumococcal whole-cell vaccine SPY1 is a potentiallysafe and less complex vaccine strategy that offersbroad protection against S. pneumoniae.

Heterologous prime-boost immunization with live SPY1 and DnaJ protein of Streptococcus pneumoniae induces strong Th1 and Th17 cellular immune responses in mice

Yulan Qiu,XueMei Zhang,Hong Wang,Xinyuan Zhang,Yunjun Mo,Xiaoyu Sun,Jichao Wang,YiBing Yin,WenChun Xu 한국미생물학회 2017 The journal of microbiology Vol.55 No.10

diseases in children under 5-year-old. Vaccine has been used as an indispensable strategy to prevent S. pneumoniae infection for more than 30 years. Our previous studies confirmed that mucosal immunization with live attenuated strain SPY1 can protect mice against nasopharyngeal colonization of S. pneumoniae and lethal pneumococcal infection, and the protective effects are comparable with those induced by commercially available 23-valent polysaccharide vaccine. However, live attenuated vaccine SPY1 needs four inoculations to get satisfactory protective effect, which may increase the risk of virulence recovery. It is reported that heterologous primeboost approach is more effective than homologous primeboost approach. In the present study, to decrease the doses of live SPY1 and improve the safety of SPY1 vaccine, we immunized mice with SPY1 and DnaJ protein alternately. Our results showed that heterologous prime-boost immunization with SPY1 and DnaJ protein could significantly reduce the colonization of S. pneumoniae in the respiratory tract of mice, and induce stronger Th1 and Th17 cellular immune responses than SPY1 alone. These results indicate heterologous prime-boost immunization method not only elicits better protective effect than SPY1 alone, but also reduces the doses of live SPY1 and decreases the risk of SPY1 vaccine. This work is the first time to study the protective efficiency with two different forms of S. pneumoniae candidate vaccine, and provides a new strategy for the development of S. pneumoniae vaccine.

Pneumococcal wall teichoic acid is required for the pathogenesis of Streptococcus pneumoniae in murine models

Hongmei Xu,Libin Wang,Jian Huang,YanQing Zhang,Feng Ma,Jianmin Wang,WenChun Xu,XueMei Zhang,YiBing Yin,KaiFeng Wu 한국미생물학회 2015 The journal of microbiology Vol.53 No.2

Pneumococcal asymptomatic colonization of the respiratory tracts is a major risk for invasive pneumococcal disease. We have previously shown that pneumococcal wall teichoic acid (WTA) was involved in pneumococcal infection of sepsis and adherence to epithelial and endothelial cells. In this study, we investigated the contribution of pneumococcal WTA to bacterial colonization and dissemination in murine models. The result showed that nasopharynx colonizing D39 bacterial cells have a distinct phenotype showing an increased exposure of teichoic acids relative to medium-grown bacteria. The WTA-deficient mutants were impaired in their colonization to the nasopharynx and lungs, and led to a mild inflammation in the lungs at 36 h post-inoculation. Pretreatment of the murine nares with WTA reduced the ability of wild type D39 bacteria to colonize the nasopharynx. In addition, the WTA-deficient strain was impaired in its ability to invade the blood and brain following intranasal administration. WTA-deficient D39 strain was reduced in C3 deposition but was more susceptible to the killing by the neutrophils as compared with its parent strain. Our results also demonstrated that the WTA enhanced pneumococcal colonization and dissemination independently of the host strains. These results indicate that WTA plays an important role in pneumococcal pathogenesis, both in colonization and dissemination processes.