Streptococcus suis serotype 2(SS2)is a zoonotic pathogen that can cause acute infection,such as septicemia in pigs and streptococcal toxic shock-like syndrome(STSLS)in humans,indicating that SS2 can evade innate immun...Streptococcus suis serotype 2(SS2)is a zoonotic pathogen that can cause acute infection,such as septicemia in pigs and streptococcal toxic shock-like syndrome(STSLS)in humans,indicating that SS2 can evade innate immunity.Macrophages perform essential antimicrobial functions in the innate immune system by engulfing and killing pathogens.Previously,a dna K mutant strain that showed impaired phagocytosis resistance ability was screened from the transposon mutant library of SS2,but the specific mechanism is unclear.In this study,we further demonstrated that DnaK was required for SS2 to be antiphagocytosed by macrophages and survive in adverse environments.A mouse challenge experiment indicated that DnaK promoted bacteremia and systemic dissemination of SS2,enhancing bacterial pathogenicity.Western blot and immunofluorescence results indicated that DnaK could be secreted by SS2 and was able to enter RAW264.7 macrophages.Then,the endocytic receptor LRP1 regulated by DnaK was identified through RNA sequencing(RNA-Seq).We found that DnaK decreased both the mRNA and protein levels of LRP1.Knockdown of the LRP1β-chain(LRP1β)significantly decreased the phagocytosis rate of the SS2 strain ZY05719,suggesting that LRP1 is a phagocytic receptor of SS2.Furthermore,inhibitor treatment assays revealed that DnaK decreased LRP1 protein levels through the transcription factor PPARγand the ubiquitin-proteasome system.In summary,DnaK contributes to the phagocytosis resistance of SS2 by decreasing LRP1 protein levels in macrophages,providing new insights into the antiphagocytosis mechanisms of SS2 and helping to understand its pathogenesis.展开更多
Streptococcus suis serotype 2(SS2)is an emerging zoonotic pathogen that causes meningitis in humans and pigs.This pathogen generates substantial economic losses in the swine industry while posing a significant threat ...Streptococcus suis serotype 2(SS2)is an emerging zoonotic pathogen that causes meningitis in humans and pigs.This pathogen generates substantial economic losses in the swine industry while posing a significant threat to public health security.The mechanisms through which SS2 penetrates the brain and induces meningitis remain incompletely understood.This study examines the role and mechanism of SS2 collagenase-like protease(Clp)in facilitating bacterial passage across the blood-brain barrier(BBB).The research demonstrates that SS2 Clp enhanced virulence and tissue colonization while promoting BBB degradation in mice.The Δclp mutant exhibited reduced ability to traverse human brain microvascular endothelial(hCMEC/D3)cell monolayers compared to wild-type SS2,while the addition of recombinant protein rClp increased permeability.Furthermore,rClp significantly enhanced SS2 adhesion to hCMEC/D3,suppressed the expression of intercellular tight junction proteins ZO-1,Occludin,and Claudin-5 independent of its enzyme activity,and triggered hCMEC/D3 apoptosis through cell receptor ligand apoptosis and mitochondrial apoptosis pathways,partially dependent on its enzyme activity,leading to BBB disruption and enhanced permeability.Additionally,Clp enhanced the infiltration of macrophages(F4/80+),monocytes(F4/80-Ly6C+),and neutrophils(Ly6G+)into the brain following SS2 infection.These findings establish that SS2 Clp is essential for bacterial passage across the BBB,offering a theoretical foundation for improved prevention and treatment strategies for SS2-induced meningitis.展开更多
Toxin–antitoxin(TA)systems,which are prevalent in bacteria and archaea,play diverse roles in bacterial physiology and have been proposed to be significant in stress adaptation.Despite the extensive characterization o...Toxin–antitoxin(TA)systems,which are prevalent in bacteria and archaea,play diverse roles in bacterial physiology and have been proposed to be significant in stress adaptation.Despite the extensive characterization of numerous TA systems in various bacteria,the investigation of these systems within Streptococcus suis is still limited.Here,we systematically analyzed the type Ⅱ TA systems of 95 S.suis genomes available in the GenBank database using TAfinder.A total of 612 putative type Ⅱ TA systems were retrieved and classified into 10 categories by phylogenetic analysis.Notably,an elevated occurrence of these TA systems was observed among the important prevalent serotypes 2,4,5,9,14,Chz,NCL1,and NCL3 strains.The following study identified the activities of TA systems using 2 strategies and confirmed the regulatory effect of HigBA on the type Ⅶ secretion system in S.suis by measuringβ-galactosidase activity and transcriptional changes.Moreover,we unveiled a hitherto uncharacterized,highly prevalent novel TA system,with the composition of antitoxin–toxin–antitoxin(SS-ATA),which regulates the downstream two-component signaling system.Altogether,this study systematically analyzed the type Ⅱ TA systems within S.suis,highlighting the widespread distribution of Hig BA and SS-ATA as important regulatory elements in S.suis.展开更多
Streptococcus suis(S.suis)is a major disease impacting pig farming globally.It can also be transferred to humans by eating raw pork.A comprehensive study was recently carried out to determine the indices throughmultip...Streptococcus suis(S.suis)is a major disease impacting pig farming globally.It can also be transferred to humans by eating raw pork.A comprehensive study was recently carried out to determine the indices throughmultiple geographic regions in China.Methods:The well-posed theorems were employed to conduct a thorough analysis of the model’s feasible features,including positivity,boundedness equilibria,reproduction number,and parameter sensitivity.Stochastic Euler,Runge Kutta,and EulerMaruyama are some of the numerical techniques used to replicate the behavior of the streptococcus suis infection in the pig population.However,the dynamic qualities of the suggested model cannot be restored using these techniques.Results:For the stochastic delay differential equations of the model,the non-standard finite difference approach in the sense of stochasticity is developed to avoid several problems such as negativity,unboundedness,inconsistency,and instability of the findings.Results from traditional stochastic methods either converge conditionally or diverge over time.The stochastic non-negative step size convergence nonstandard finite difference(NSFD)method unconditionally converges to the model’s true states.Conclusions:This study improves our understanding of the dynamics of streptococcus suis infection using versions of stochastic with delay approaches and opens up new avenues for the study of cognitive processes and neuronal analysis.Theplotted interaction behaviour and new solution comparison profiles.展开更多
[Objective] This study aimed to establish a method for quantitative detection of mRNA transcriptional level of SS2 adhesive related-factors of Streptococcus suis serotype 2 （SS2） by fluorescent quantitative PCR. []V...[Objective] This study aimed to establish a method for quantitative detection of mRNA transcriptional level of SS2 adhesive related-factors of Streptococcus suis serotype 2 （SS2） by fluorescent quantitative PCR. []Vlethod] The gene fragments en- coding SS2 adhesive related-factors MRP, FBPS and CPS2J and a housekeeping gene aroA were amplified by reverse transcription PCR from the total RNA of SS2, cloned, and sequenced. The recombinant plasmids containing the target genes were constructed, and used as templates in Real-time PCR. [Result] Dynamic curves, stan- dard curves and melting curves of the adhesive related-factors and aroA were ob- tained by the optimized Real-time PCR system. The standard curves showed a good linear relationship between template copy number and circulation number, and the correlation coefficients （FF） of the standard curves were over 0.995. Also, these as- says were highly specific a^d there was single specific melting peak for every gene. Moreover, the assays were highly sensitive and had a detection limit of 1.0×102 copies in 1 μl of initial templates. Finally, it was highly repeatable and had a coeffi- cient of variation less than 2% for intra-assay. [Conclusion] This study will provide a way to reveal the adhesion mechanism of SS2 to different host cells at molecular level.展开更多
Respiratory diseases are one of the most important health problems in pig herds. The porcine respiratory disease complex (PRDC) is the term used to describe pneumonic diseases caused by multiple infectious agents that...Respiratory diseases are one of the most important health problems in pig herds. The porcine respiratory disease complex (PRDC) is the term used to describe pneumonic diseases caused by multiple infectious agents that provoke weight loss in animals or death. In the PRDC multiple pathogens (bacteria and/or viruses) work in combination to induce this respiratory disease. Within this complex, Actinobacillus pleuropneumoniae, Streptococcus suis, Pasteurella multocida, Bordetella bronchiseptica, Haemophilus parasuis and Mycoplasma hyopneumoniae are the main bacterial pathogens involved in great economic losses to the swine industry. The aim of this work was to estimate the presence of A. pleuropneumoniae, S. suis, P. multocida, B. bronchiseptica, H. parasuis and M. hyopneumoniae in the upper respiratory tract of pigs in representative swine farms inAguascalientes,Mexico, using PCR technique. The study was performed in 14 swine farms. We obtained a total of 212 nasal swabs. Near 20% of samples were positive for A. pleuropneumoniae (located in the 79% of farms);17% were positive for S. suis (in 86% of farms), of these, 3% were S. suis serovar 2;30% were positive for H. parasuis (93% of farms);23% of the samples to P. multocida (in 79% of farms);and 19% to M. hyopneumoniae (in 64% of farms). B. bronchiseptica was not detected in this study. The results obtained show that bacterial pathogens of PRDC were present in the upper respiratory tract of pigs in all farms studied;therefore, these pathogens are widely disseminated in pig farms of Aguascalientes, Mexico.展开更多
直序码分多址系统(DS-CDMA)与多载波码分多址系统(MC-CDMA)是高速率无线通信中两个重要的CDMA技术。文章将一种改进的每个用户最小均方差(PU-MMSE)检测技术应用于频域均衡的DS-CDMA系统中,并通过计算机仿真分别对传统的每个载波最小均方...直序码分多址系统(DS-CDMA)与多载波码分多址系统(MC-CDMA)是高速率无线通信中两个重要的CDMA技术。文章将一种改进的每个用户最小均方差(PU-MMSE)检测技术应用于频域均衡的DS-CDMA系统中,并通过计算机仿真分别对传统的每个载波最小均方差(PC-MMSE)与PU-MMSE两种检测技术应用于Wi MAX SUI信道下的DS-CDMA和MC-CDMA系统进行了性能比较。实验结果表明:使用了PU-MMSE检测技术的DS-CDMA系统能够更好地消除串行干扰,且与使用相同检测技术的MC-CDMA系统的性能几乎没有差别,但是却大大降低了峰值平均功率比(PAPR)。展开更多
基金funded by the National Key Research and Development Program of China(2021YFD1800400)the National Natural Science Foundation of China(32373018)+2 种基金Jiangsu Agriculture Science and Technology Innovation Fund,China(CX(23)1029)the Excellent Research Innovation Team in Universities in Anhui Province,China(2022AH010088)the Shennong Scholar Project of Anhui Agricultural University,China(rc392101)。
文摘Streptococcus suis serotype 2(SS2)is a zoonotic pathogen that can cause acute infection,such as septicemia in pigs and streptococcal toxic shock-like syndrome(STSLS)in humans,indicating that SS2 can evade innate immunity.Macrophages perform essential antimicrobial functions in the innate immune system by engulfing and killing pathogens.Previously,a dna K mutant strain that showed impaired phagocytosis resistance ability was screened from the transposon mutant library of SS2,but the specific mechanism is unclear.In this study,we further demonstrated that DnaK was required for SS2 to be antiphagocytosed by macrophages and survive in adverse environments.A mouse challenge experiment indicated that DnaK promoted bacteremia and systemic dissemination of SS2,enhancing bacterial pathogenicity.Western blot and immunofluorescence results indicated that DnaK could be secreted by SS2 and was able to enter RAW264.7 macrophages.Then,the endocytic receptor LRP1 regulated by DnaK was identified through RNA sequencing(RNA-Seq).We found that DnaK decreased both the mRNA and protein levels of LRP1.Knockdown of the LRP1β-chain(LRP1β)significantly decreased the phagocytosis rate of the SS2 strain ZY05719,suggesting that LRP1 is a phagocytic receptor of SS2.Furthermore,inhibitor treatment assays revealed that DnaK decreased LRP1 protein levels through the transcription factor PPARγand the ubiquitin-proteasome system.In summary,DnaK contributes to the phagocytosis resistance of SS2 by decreasing LRP1 protein levels in macrophages,providing new insights into the antiphagocytosis mechanisms of SS2 and helping to understand its pathogenesis.
基金supported by the National Key Research and Development Program of China(2021FYD1800405)the National Natural Science Foundation of China(32072823).
文摘Streptococcus suis serotype 2(SS2)is an emerging zoonotic pathogen that causes meningitis in humans and pigs.This pathogen generates substantial economic losses in the swine industry while posing a significant threat to public health security.The mechanisms through which SS2 penetrates the brain and induces meningitis remain incompletely understood.This study examines the role and mechanism of SS2 collagenase-like protease(Clp)in facilitating bacterial passage across the blood-brain barrier(BBB).The research demonstrates that SS2 Clp enhanced virulence and tissue colonization while promoting BBB degradation in mice.The Δclp mutant exhibited reduced ability to traverse human brain microvascular endothelial(hCMEC/D3)cell monolayers compared to wild-type SS2,while the addition of recombinant protein rClp increased permeability.Furthermore,rClp significantly enhanced SS2 adhesion to hCMEC/D3,suppressed the expression of intercellular tight junction proteins ZO-1,Occludin,and Claudin-5 independent of its enzyme activity,and triggered hCMEC/D3 apoptosis through cell receptor ligand apoptosis and mitochondrial apoptosis pathways,partially dependent on its enzyme activity,leading to BBB disruption and enhanced permeability.Additionally,Clp enhanced the infiltration of macrophages(F4/80+),monocytes(F4/80-Ly6C+),and neutrophils(Ly6G+)into the brain following SS2 infection.These findings establish that SS2 Clp is essential for bacterial passage across the BBB,offering a theoretical foundation for improved prevention and treatment strategies for SS2-induced meningitis.
基金supported by the National Key Research and Development Program of China(2022YFD1800904)the National Natural Science Foundation of China(31972650 and 32102673)+1 种基金the Postgraduate Research&Practice Innovation Program of Jiangsu Province,China(KYCX22_0780)the China Postdoctoral Science Foundation(2020M682297)。
文摘Toxin–antitoxin(TA)systems,which are prevalent in bacteria and archaea,play diverse roles in bacterial physiology and have been proposed to be significant in stress adaptation.Despite the extensive characterization of numerous TA systems in various bacteria,the investigation of these systems within Streptococcus suis is still limited.Here,we systematically analyzed the type Ⅱ TA systems of 95 S.suis genomes available in the GenBank database using TAfinder.A total of 612 putative type Ⅱ TA systems were retrieved and classified into 10 categories by phylogenetic analysis.Notably,an elevated occurrence of these TA systems was observed among the important prevalent serotypes 2,4,5,9,14,Chz,NCL1,and NCL3 strains.The following study identified the activities of TA systems using 2 strategies and confirmed the regulatory effect of HigBA on the type Ⅶ secretion system in S.suis by measuringβ-galactosidase activity and transcriptional changes.Moreover,we unveiled a hitherto uncharacterized,highly prevalent novel TA system,with the composition of antitoxin–toxin–antitoxin(SS-ATA),which regulates the downstream two-component signaling system.Altogether,this study systematically analyzed the type Ⅱ TA systems within S.suis,highlighting the widespread distribution of Hig BA and SS-ATA as important regulatory elements in S.suis.
基金supported by the Deanship of Scientific Research,Vice Presidency for Graduate Studies and Scientific Research,King Faisal University,Saudi Arabia[KFU250259].
文摘Streptococcus suis(S.suis)is a major disease impacting pig farming globally.It can also be transferred to humans by eating raw pork.A comprehensive study was recently carried out to determine the indices throughmultiple geographic regions in China.Methods:The well-posed theorems were employed to conduct a thorough analysis of the model’s feasible features,including positivity,boundedness equilibria,reproduction number,and parameter sensitivity.Stochastic Euler,Runge Kutta,and EulerMaruyama are some of the numerical techniques used to replicate the behavior of the streptococcus suis infection in the pig population.However,the dynamic qualities of the suggested model cannot be restored using these techniques.Results:For the stochastic delay differential equations of the model,the non-standard finite difference approach in the sense of stochasticity is developed to avoid several problems such as negativity,unboundedness,inconsistency,and instability of the findings.Results from traditional stochastic methods either converge conditionally or diverge over time.The stochastic non-negative step size convergence nonstandard finite difference(NSFD)method unconditionally converges to the model’s true states.Conclusions:This study improves our understanding of the dynamics of streptococcus suis infection using versions of stochastic with delay approaches and opens up new avenues for the study of cognitive processes and neuronal analysis.Theplotted interaction behaviour and new solution comparison profiles.
基金Supported by National Natural Science Foundation of China(31072155)Natural Science Foundation of Jiangsu Province(BK2010068)+1 种基金Fund for Independent Innovation of Agricultural Science in Jiangsu Province[CX(11)2060]Special Fund for Agroscientific Research in the Public Interest(201303041)~~
文摘[Objective] This study aimed to establish a method for quantitative detection of mRNA transcriptional level of SS2 adhesive related-factors of Streptococcus suis serotype 2 （SS2） by fluorescent quantitative PCR. []Vlethod] The gene fragments en- coding SS2 adhesive related-factors MRP, FBPS and CPS2J and a housekeeping gene aroA were amplified by reverse transcription PCR from the total RNA of SS2, cloned, and sequenced. The recombinant plasmids containing the target genes were constructed, and used as templates in Real-time PCR. [Result] Dynamic curves, stan- dard curves and melting curves of the adhesive related-factors and aroA were ob- tained by the optimized Real-time PCR system. The standard curves showed a good linear relationship between template copy number and circulation number, and the correlation coefficients （FF） of the standard curves were over 0.995. Also, these as- says were highly specific a^d there was single specific melting peak for every gene. Moreover, the assays were highly sensitive and had a detection limit of 1.0×102 copies in 1 μl of initial templates. Finally, it was highly repeatable and had a coeffi- cient of variation less than 2% for intra-assay. [Conclusion] This study will provide a way to reveal the adhesion mechanism of SS2 to different host cells at molecular level.
文摘Respiratory diseases are one of the most important health problems in pig herds. The porcine respiratory disease complex (PRDC) is the term used to describe pneumonic diseases caused by multiple infectious agents that provoke weight loss in animals or death. In the PRDC multiple pathogens (bacteria and/or viruses) work in combination to induce this respiratory disease. Within this complex, Actinobacillus pleuropneumoniae, Streptococcus suis, Pasteurella multocida, Bordetella bronchiseptica, Haemophilus parasuis and Mycoplasma hyopneumoniae are the main bacterial pathogens involved in great economic losses to the swine industry. The aim of this work was to estimate the presence of A. pleuropneumoniae, S. suis, P. multocida, B. bronchiseptica, H. parasuis and M. hyopneumoniae in the upper respiratory tract of pigs in representative swine farms inAguascalientes,Mexico, using PCR technique. The study was performed in 14 swine farms. We obtained a total of 212 nasal swabs. Near 20% of samples were positive for A. pleuropneumoniae (located in the 79% of farms);17% were positive for S. suis (in 86% of farms), of these, 3% were S. suis serovar 2;30% were positive for H. parasuis (93% of farms);23% of the samples to P. multocida (in 79% of farms);and 19% to M. hyopneumoniae (in 64% of farms). B. bronchiseptica was not detected in this study. The results obtained show that bacterial pathogens of PRDC were present in the upper respiratory tract of pigs in all farms studied;therefore, these pathogens are widely disseminated in pig farms of Aguascalientes, Mexico.
文摘直序码分多址系统(DS-CDMA)与多载波码分多址系统(MC-CDMA)是高速率无线通信中两个重要的CDMA技术。文章将一种改进的每个用户最小均方差(PU-MMSE)检测技术应用于频域均衡的DS-CDMA系统中,并通过计算机仿真分别对传统的每个载波最小均方差(PC-MMSE)与PU-MMSE两种检测技术应用于Wi MAX SUI信道下的DS-CDMA和MC-CDMA系统进行了性能比较。实验结果表明:使用了PU-MMSE检测技术的DS-CDMA系统能够更好地消除串行干扰,且与使用相同检测技术的MC-CDMA系统的性能几乎没有差别,但是却大大降低了峰值平均功率比(PAPR)。
