The functional realization of proteins and other biological macromolecules depends on conformational dynamics and allosteric regulation, and elucidating their molecular mechanisms is an important foundation for understanding life processes. Molecular dynamics simulations are a powerful tool for investigating conformational evolution at the atomic level. However, traditional methods are limited by simulation timescales and high free-energy barriers, making it difficult to effectively capture rare conformations and their transition pathways. As a result, the development of enhanced sampling techniques has become key to overcoming this bottleneck. As a classical enhanced sampling technique, metadynamics suffers from several shortcomings, including strong dependence on collective variables and significant errors caused by bias potential accumulation. This article reviews three major improvement strategies. The first combines stochastic resetting with metadynamics, using trajectory-resetting mechanisms to improve sampling efficiency while avoiding the difficulty of optimizing collective variables. The second, SinkMeta, employs a “sinking” bias effect to enable efficient exploration of specific regions and paths. The third, OPES-based hybrid methods, improve the stability of free-energy estimation by optimizing the target distribution or the way the bias is constructed. These methods provide new ideas for characterizing free-energy landscapes and studying conformational transitions in complex biological systems, while also promoting the continued development of enhanced sampling methodologies.

Objective To gain insights into the biological characteristics of different populations of Culex tritaeniorhynchus within and around the Yellow Sea wetland from the perspective of the occurrence of resistance, we investigated the levels of resistance to deltamethrin and kdr gene mutation in the wetland and its peripheral areas. Methods Specimens were collected from Cx. tritaeniorhynchus populations at two monitoring sites in the Rare Bird National Nature Reserve and Tiaozi Ni Wetland Scenic Area, and also from two populations in Yancheng City and the Liuhe District of Nanjing, and the resistance of these mosquitoes to deltamethrin was determined using the CDC biotest bottle method. For each concentration of deltamethrin assessed, a random subset of exposed specimens was selected for amplification of the kdr gene fragment, followed by Sanger sequencing to identify and analyze resistance-associated mutations. Results The LC50 levels of deltamethrin among mosquitoes from the four populations in Luhe, Yancheng, the Rare Bird National Nature Reserve and the Tiaozi Ni Wetland Scenic Area were 2.048 5, 7.798 2, 3.473 3, and 17.695 5 mg/mL, respectively, with corresponding concentrations of deltamethrin ranging from 0.005 to 5.000,0.050 to 50.000,0.050 to 25.000 and 0.050 to 50.000 mg/mL, respectively. Furthermore, the ranges of the KT50 values were 11.76-107.43, 67.05-216.30,29.77-107.43 and 28.40-329.51 min; the 1-h knockdown rates were 34.58%-99.15%, 9.52%-43.80%, 55.09%-73.01%, and 10.09%-68.07%; and the 24-h mortality rates were 12.15%-67.52%,9.52%-79.56%,13.17%-82.21%, and 11.01%-78.99%, respectively. With respect to kdr gene mutation, we assayed a total of 63,70,59, and 57 mosquitoes for the four populations, for which we detected L1014F mutation frequencies of 14.29%, 35.00%, 20.34%, and 31.58%, respectively, with a majority of these mutations being heterozygous for resistance. In addition, five adult mosquitoes were identified has having synonymous mutations at site 1011[i. e. , AAT(asparagine)mutation to AAC(asparagine)]. Conclusions Our findings revealed the clear resistance of Cx. tritaeniorhynchus to deltamethrin in the Yancheng region of the Yellow Sea wetland, and the resistance phenotype and kdr frequency of Cx. tritaeniorhynchus in the wetland environment were comparable to those of Cx. tritaeniorhynchus in the wetland environment, thereby indicating that the resistance of different populations of Cx. tritaeniorhynchus was homogeneous under the pressure of different insecticide selection within and around the wetland. However, the underlying mechanisms need to be further studied.

A recombinant adenovirus(rAd)for expression of Mycobacterium tuberculosis(M.tb)c-di-AMP phosphodiesterase CnpB was constructed,and its induced humoral immune response was detected.The codon-optimized gene of M.tb CnpB was cloned into the adenoviral plasmid pcADV.The recombinant plasmid pcADV-CnpB was transfected into HEK293T cells,and expression was detected with Western blot.The recombinant plasmid pcADV-CnpB and the backbone plasmid were co-transfected into HEK293T cells to obtain the recombinant adenovirus rAd-CnpB.rAd-CnpB was amplified in HEK293T cells,and the target protein expression of rAd-CnpB was detected with Western blot and immunofluorescence.Mice were immunized with rAd-CnpB intranasally,and their sera and bronchoalveolar lavage fluid(BALF)were collected.ELISA was used to detect levels of antigen-specific antibodies.Restriction enzyme digestion and sequencing indicated that the recombinant plasmid pcADV-CnpB was successfully constructed and led to protein expression in eukaryotic cells.rAd-CnpB was packaged and produced in HEK293T cells.After amplification and purification,rAd-CnpB with a titer of 5.53×1010 PFU/mL was obtained.rAd-CnpB led to CnpB expression in HEK293T cells.Intranasal immunization with rAd-CnpB increased levels of IgG and secretory IgA in BALF and led to high levels of IgG in sera.rAd-CnpB,the recombinant adenovirus for expression of c-di-AMP phosphodiesterase CnpB was successfully constructed,and was found to induce antigen-specific humoral and mucosal immune responses through mucosal immunization.Thus,rAd-CnpB may be used in further research on new TB vaccine strategies.

This study assessed the role and mechanism of the recombinant Bacillus Calmette-Gue?rin vaccine(rBCG)with c-di-AMP adjuvant in regulating metabolism and immunity in epididymal white adipose(eWAT)in mice.Male C57BL/6 mice were intravenously immunized with BCG and rBCG,and their body weights were monitored.eWAT was isolated from the mice,and the stromal vascular fractions(SVFs)cell number was counted with a hemocytometer.Sections of mouse adipose tissue were prepared,and the size,number,and morphology of eWAT adipocytes and crown-like structure(CLS)formation were compared under a microscope after HE staining.The transcription levels of lipid metabolism-associated factors,cytokines and aging-associated genes in each group were determined with qRT-PCR.The body weights of mice gradually increased after immunization with BCG and rBCG.The proportions of eWAT increased,and the SVFs cell number decreased,in rBCG immunized mice.HE staining indicated that BCG immunization promoted hyperplasia,whereas rBCG immunization promoted hypertrophy of eWAT adipocytes;moreover,both BCG and rBCG immunization induced CLS formation in eWAT.The qRT-PCR results indicated that rBCG immunization inhibited the expression of genes associated with lipolysis and energy expenditure in eWAT.BCG immunization had little effect on cytokine transcription,whereas rBCG significantly induced the transcription of IFN-γ and IL-1Ra,and inhibited that of IL-15 and IL-2,but did not induce the expression of aging-associated genes.Thus,rBCG immunization induced eWAT adipocyte hypertrophy,which was associated with the inhibition of eWAT lipolysis and the regulation of cytokine expression.

The study was aimed at identifying the diversity of tick species in selected areas of Qinghai,to analyze the genetic differentiation characteristics of tick-borne spotted fever group rickettsiae(SFGR),and to provide the theoretical basis for SFGR prevention and control in the region.The 16S rRNA gene was used for molecular biological identification of 446 collected tick samples,and the infection characteristics of SFGR in tick samples were determined according to the SFGR outer membrane protein A(ompA)gene.Haplotype analysis,phylogenetic tree construction,and estimation of differentiation times for SFGR were conducted in DNASP v6,IQ-tree v2.2.0,and BEAST v2.7.4 software.The obtained 446 tick samples belonged to three categories:(1)Haemaphy-salis spp.,including Haemaphysalis qinghaiensis(n=192)and H.danieli(n=37);(2)Dermacentor spp.,including Dermacentor ever-estianus(n=121),D.nuttalli(n=55),and D.silvarum(n=36);and(3)Hyalomma marginatum(n=5).Rickettsia raoultii was de-tected in D.everestianus,D.silvarum,D.nuttalli,H.qinghaiensis,and H.danieli,with infection rates of 95.9%,80.6%,69.1%,4.1%,and 2.7%,respectively.R.sibirica subsp.sibirica BJ-90 was found only in D.silvarum and D.nuttalli,with infection rates of 5.6%and 1.8%,respectively.The Candidatus R.gannanii F107 was found in H.danieli and H.qinghaiensis,with infection rates of 16.2%and 7.8%,respectively.Ca.R.hongyuanensis was detected only in H.qinghaiensis,with a prevalence of 16.3%.The prevalence of R.aeschlimannii was 20%and 2.7%in Hy.marginatum and H.danieli,respectively.Haplotype and nucleotide polymorphism analy-ses revealed 13 haplotypes in R.raoultii,with haplotype H13 as the dominant haplotype(42/192);seven haplotypes in Ca.R.ganna-nii F107,with haplotype H4 as the dominant haplotype(4/18);and three haplotypes in Ca.R.hongyuanensis,with haplotype H1 as the dominant haplotype(11/13).The phylogenetic tree indicated that the sequences of R.raoultii in selected areas of Qinghai and R.rhipicephali clustered into one branch;Ca.R.hongyuanensis and Ca.R.gannanii F107 clustered into one branch;and R.sibirica subsp.sibirica BJ-90 clustered into one branch with R.sibirica.Estimates of differentiation time revealed that the mean differentiation time for the six Rickettsia was approximately 2 000 Mya(95%CI:1 999.08-2 001.02 Mya).The tick species distributed in selected ar-eas of Qinghai are diverse,and this study provides the first report of Hy.marginatum in Qinghai Province.SFGR significantly varied in prevalence among tick species and showed high genetic diversity.

Bone morphogenetic proteins are a large subclass of the transforming growth factor β family,and Their signaling pathways are mainly classified into two kinds based on whether they depend on Smad protein to mediate or not.BMP signaling pathways are involved in regulating cell proliferation and differentiation,as well as the formation and development of multiple tissues and organs.Recent studies have shown that BMP signaling path-ways mainly promote the differentiation and growth of neurons and astrocytes,and are closely related to the my-elination of oligodendrocytes.In addition,BMP signaling pathways also play an important role in the occurrence of central nervous system diseases,such as spinal cord injuries,multiple sclerosis,neural tube defects,and Parkin-son's disease.This article reviews the BMP signaling pathways'composition,transduction mechanism and their role in the central nervous system and related diseases,in order to provide more potential ideas for basic research and clinical treatment of central nervous system diseases.

This study was aimed at investigating the effects and mechanisms of Toxoplasma gondii type Ⅰ(RH strain)ROP16 protein on proliferation and the cell cycle in mouse alveolar macrophage MH-S cells.We constructed a Toxoplasma gondii type Ⅰ(RH)ROP16 overexpression lentivirus,transduced MH-S cells,and then screened cells with puromycin to obtain a cell line stably overexpressing ROP16Ⅰ.RT-qPCR and western blotting were used to verify expression effects,CCK-8 assays were used to detect cell proliferation activity,and flow cytometry was used to detect cell cycle changes.Western blotting and RT-qPCR were used to detect the expression levels of p53,p21,CDK6,Cyclin D1,STAT3,p-STAT3(Y705),and JAK1 proteins or genes,and immunofluorescence was used to detect the expression levels of ROP16Ⅰ and p-STAT3(Y705)and their subcellular co-localization in MH-S cells.ROP16Ⅰ protein and gene expression were detected in MH-S cells transduced with lentivirus for ROP16Ⅰ overexpression.CCK-8 assays revealed that ROP16Ⅰ promoted the proliferation of MH-S cells(P＜0.01)and enhanced cell viability.Flow cytometry revealed that ROP16Ⅰ overexpression decreased the G0/G1 phase and elevated the G2 and S phases of the cell cycle in MH-S cells(P＜0.01 or P＜0.05).Compared with the MH-S cell group and MH-S-empty vector group,the MH-S-ROP16 cell group showed lower expression of p53 and p21 proteins;higher expression of CDK6,Cyclin D1,p-STAT3(Y705),and JAK1 proteins;lower expression of p53 and p21 mRNAs;and higher expression of CDK6 and Cyclin D1 mRNAs(all P＜0.01).Immunofluorescence revealed that ROP16Ⅰ co-localized with p-STAT3(Y705)in the nucleus and surrounding cytoplasm.Therefore,Toxoplasma gondii type Ⅰ(RH)ROP16Ⅰ protein activates the JAK-STAT3 pathway;shortens the G0/G1 phase and lengthens the G2/S phase of the cell cycle;and promotes cell proliferation.These findings provide a theoretical basis for revealing the mechanism of immune evasion of Toxoplasma gondii,and lay a foundation for research on the prevention and treatment of Toxoplasma gondii pneumonia.

This study was aimed at investigating the effects and mechanisms of Toxoplasma gondii type Ⅰ(RH strain)ROP16 protein on proliferation and the cell cycle in mouse alveolar macrophage MH-S cells.We constructed a Toxoplasma gondii type Ⅰ(RH)ROP16 overexpression lentivirus,transduced MH-S cells,and then screened cells with puromycin to obtain a cell line stably overexpressing ROP16Ⅰ.RT-qPCR and western blotting were used to verify expression effects,CCK-8 assays were used to detect cell proliferation activity,and flow cytometry was used to detect cell cycle changes.Western blotting and RT-qPCR were used to detect the expression levels of p53,p21,CDK6,Cyclin D1,STAT3,p-STAT3(Y705),and JAK1 proteins or genes,and immunofluorescence was used to detect the expression levels of ROP16Ⅰ and p-STAT3(Y705)and their subcellular co-localization in MH-S cells.ROP16Ⅰ protein and gene expression were detected in MH-S cells transduced with lentivirus for ROP16Ⅰ overexpression.CCK-8 assays revealed that ROP16Ⅰ promoted the proliferation of MH-S cells(P＜0.01)and enhanced cell viability.Flow cytometry revealed that ROP16Ⅰ overexpression decreased the G0/G1 phase and elevated the G2 and S phases of the cell cycle in MH-S cells(P＜0.01 or P＜0.05).Compared with the MH-S cell group and MH-S-empty vector group,the MH-S-ROP16 cell group showed lower expression of p53 and p21 proteins;higher expression of CDK6,Cyclin D1,p-STAT3(Y705),and JAK1 proteins;lower expression of p53 and p21 mRNAs;and higher expression of CDK6 and Cyclin D1 mRNAs(all P＜0.01).Immunofluorescence revealed that ROP16Ⅰ co-localized with p-STAT3(Y705)in the nucleus and surrounding cytoplasm.Therefore,Toxoplasma gondii type Ⅰ(RH)ROP16Ⅰ protein activates the JAK-STAT3 pathway;shortens the G0/G1 phase and lengthens the G2/S phase of the cell cycle;and promotes cell proliferation.These findings provide a theoretical basis for revealing the mechanism of immune evasion of Toxoplasma gondii,and lay a foundation for research on the prevention and treatment of Toxoplasma gondii pneumonia.

Bone morphogenetic proteins are a large subclass of the transforming growth factor β family,and Their signaling pathways are mainly classified into two kinds based on whether they depend on Smad protein to mediate or not.BMP signaling pathways are involved in regulating cell proliferation and differentiation,as well as the formation and development of multiple tissues and organs.Recent studies have shown that BMP signaling path-ways mainly promote the differentiation and growth of neurons and astrocytes,and are closely related to the my-elination of oligodendrocytes.In addition,BMP signaling pathways also play an important role in the occurrence of central nervous system diseases,such as spinal cord injuries,multiple sclerosis,neural tube defects,and Parkin-son's disease.This article reviews the BMP signaling pathways'composition,transduction mechanism and their role in the central nervous system and related diseases,in order to provide more potential ideas for basic research and clinical treatment of central nervous system diseases.

Objective To investigate the clinical features of patients with China Liver Cancer Staging(CNLC)stage Ⅲhepatocellular carcinoma(HCC)achieving five-year sustained complete remission(CR)after local treatment combined with systemic therapy,as well as potential contributing factors,and to provide a reference for optimizing the treatment of advanced HCC.Methods A retrospective analysis was performed for the clinical data of six patients with CNLC stage Ⅲ HCC who were treated in Department of Interventional Radiology,The First Affiliated Hospital of Soochow University,from January 2016 to December 2019 and achieved five-year sustained CR.Baseline characteristics,treatment modalities,and follow-up data were summarized,and a literature review was performed.Results The six patients had a mean age of 58.3±10.1 years,among whom five had stage Ⅲa HCC and one had stage Ⅲb HCC,and all patients had a history of hepatitis.The mean preoperative MELD score was 8.2±0.8 for the six patients,and there were five patients with Child-Pugh class A liver function and one with Child-Pugh class B liver function.All patients underwent transcatheter arterial chemoembolization,followed by sequential targeted drug therapy after surgery,with sorafenib for four patients and lenvatinib for two patients.Four patients with main portal vein tumor thrombus also received 125I seed implantation,one patient with the single-nodule type underwent radiofrequency ablation,and three patients received immunotherapy with camrelizumab.The median time to AFP normalization was 6 months,the median time from treatment to CR was 5.5 months,and the median follow-up time was 63 months.Conclusion Good liver function at baseline,an early and rapid reduction in AFP,and the combination of local treatment and systemic therapy are key factors for achieving long-term CR in patients with advanced HCC.Multi-center large-scale studies are needed in the future to further explore prognostic factors and optimize treatment regimens.