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1.
PeerJ Comput Sci ; 10: e1983, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38660165

RESUMO

Analyzing and obtaining useful information is challenging when facing a new complex system. Traditional methods often focus on specific structural aspects, such as communities, which may overlook the important features and result in biased conclusions. To address this, this article suggests an adaptive algorithm for exploring complex system structures using a generative model. This method calculates and optimizes node parameters, which can reflect the latent structural characteristics of the complex system. The effectiveness and stability of this method have been demonstrated in comparative experiments on 10 sets of benchmark networks using our model parameter configuration scheme. To enhance adaptability, algorithm fusion strategies were also proposed and tested on two real-world networks. The results indicate that the algorithm can uncover multiple structural features, including clustering, overlapping, and local chaining. This adaptive algorithm provides a promising approach for exploring complex system structures.

2.
Sensors (Basel) ; 24(5)2024 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-38475007

RESUMO

Multi-degree-of-freedom piezoelectric motors have the advantages of high torque and resolution, simple structure, and direct drive, which are widely used in robot wrist joints, deep-sea mechanisms, medical equipment, and space mechanisms. To solve the problems of high force/torque coupling degree and ball low stator and rotor bonding strength of the traditional traveling wave type three-degree-of-freedom piezoelectric spherical motor, a new structure of ball-hinged piezoelectric spherical motor is proposed. Through coordinate transformation and force analysis, the driven mathematical model of the spherical motor is given. The model shows that the three degrees of freedom of the motor are coupled with each other. According to the mathematical model of the spherical motor, the mechanical properties of the motor are analyzed by the computer simulation. The results show that the stalling torque coefficient kt has a linear relationship with the friction coefficient ε and the stator preload Fc, has a nonlinear relationship with the stator radius R and the rotor radius r, and increases with the increase of R and decreases with the increase of r. The no-load speed of motor ωn is not related to the friction coefficient ε and the stator preload Fc, and increases with the increase of R and decreases with the increase of r. The anisotropic characteristics of torque and speed of a spherical motor are further analyzed, which lays a theoretical foundation for the drive control of a spherical motor.

4.
Int J Artif Organs ; 46(10-11): 569-573, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37698036

RESUMO

OBJECTIVE: We aimed to elucidate the effects of the micro-structure of the pyrolytic carbon for artificial heart valves on its hydrodynamic performance. METHODS: Bileaflet mechanical valves of GKS 23 and 29 A were randomly selected. According to ISO5840, mean transvalvular pressure (MPG), regurgitation fraction (RF), and effective orifice area (EOA) of valve were assessed. Then, parallel-groove pattern was constructed by laser etching on leaflet surface, and the valves were subjected again to the same test. RESULTS: Compared with before patterning at 2, 3.5, 5, and 7 L/min, the MPG of the valves in two specifications were higher, the EOA was larger in 23 A, but smaller in 29 A, and the RF was contrary to EOA. At 5 L/min, the RF in both specifications was lower after etching at 45 bpm. At 70 bpm however, the RF in 23 A decreased, in 29 A increased. CONCLUSION: The parallel-groove pattern on leaflet surface affected the hemodynamic performance of the valve prostheses.


Assuntos
Bioprótese , Próteses Valvulares Cardíacas , Hidrodinâmica , Hemodinâmica , Desenho de Prótese , Valva Aórtica
5.
Microbiol Spectr ; 11(4): e0046023, 2023 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-37458592

RESUMO

Increasing evidence shows that protein lysine acetylation is involved in almost every aspect of cellular physiology in bacteria. Yersinia pestis is a flea-borne pathogen responsible for millions of human deaths in three global pandemics. However, the functional role of lysine acetylation in this pathogen remains unclear. Here, we found more acetylated proteins and a higher degree of acetylation in Y. pestis grown under mammalian host (Mh) conditions than under flea vector (Fv) conditions, suggesting that protein acetylation could significantly change during fleabite transmission. Comparative acetylome analysis of mutants of YfiQ and CobB, the major acetyltransferase and deacetylase of Y. pestis, respectively, identified 23 YfiQ-dependent and 315 CobB-dependent acetylated proteins. Further results demonstrated that acetylation of Lys73 of the SlyA protein, a MarR-family transcriptional regulator, inhibits its binding to the promoter of target genes, including hmsT that encodes diguanylate cyclase responsible for the synthesis of c-di-GMP, and significantly enhances biofilm formation of Y. pestis. Our study presents the first extensive acetylome data of Y. pestis and a critical resource for the functional study of lysine acetylation in this pathogen. IMPORTANCE Yersinia pestis is the etiological agent of plague, historically responsible for three global pandemics. The 2017 plague epidemic in Madagascar was a reminder that Y. pestis remains a real threat in many parts of the world. Plague is a zoonotic disease that primarily infects rodents via fleabite, and transmission of Y. pestis from infected fleas to mammals requires rapid adaptive responses to adverse host environments to establish infection. Our study provides the first global profiling of lysine acetylation derived from mass spectrometry analysis in Y. pestis. Our data set can serve as a critical resource for the functional study of lysine acetylation in Y. pestis and provides new molecular insight into the physiological role of lysine acetylation in proteins. More importantly, we found that acetylation of Lys73 of SlyA significantly promotes biofilm formation of Y. pestis, indicating that bacteria can use lysine acetylation to fine-tune the expression of genes to improve adaptation.


Assuntos
Peste , Sifonápteros , Yersinia pestis , Animais , Humanos , Yersinia pestis/metabolismo , Peste/microbiologia , Lisina/metabolismo , Acetilação , Sifonápteros/microbiologia , Biofilmes , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Mamíferos
6.
Vaccines (Basel) ; 11(5)2023 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-37243072

RESUMO

For SARS-CoV-2 mutants, the effectiveness of the COVID-19 vaccines is still controversial. In this study, we aimed to investigate the clinical characteristics of Omicron-infected patients who completed primary immunization and booster immunization, respectively, during the rapid propagation of the Omicron variant in China. A total of 932 patients with confirmed SARS-CoV-2 infection from 18 December 2022 to 1 January 2023 were included in this survey by filling out questionnaires online. The enrolled patients were divided into the primary immunization group and the booster immunization group according to their vaccination status. During the whole course of disease, the most frequent symptoms were fever (90.6%), cough (84.3%), weakness (77.4%), headache and dizziness (76.1%), and myalgia (73.9%). Nearly 90% of the patients had symptoms lasting for less than 10 days, and 39.8% of the patients ended the course of the disease in 4-6 days. A total of 58.8% of these patients had a fever with a maximum body temperature of over 38.5 °C. Moreover, 61.4% of the patients had a fever that lasted less than 2 days. There were no obvious differences in initial symptoms, cardinal symptoms, symptom duration time, maximum body temperature, and fever duration time between the two groups of patients. In addition, no significant difference was found in the positive or negative conversion time of SARS-CoV-2 antigen/nucleic acid between the two groups of patients. For mild patients with Omicron breakthrough infection, enhanced immunization has no significant impact on the clinical performance and duration of viral infection compared with primary immunization. The reasons behind the different clinical manifestations of patients with mild symptoms after the breakthrough infection of the Omicron strain are still worth further research. Heterologous vaccination may be a better strategy for enhanced immunization, which can help improve the immune protection ability of the population. Further research should be carried out on vaccines against mutant strains and spectral anti-COVID-19 vaccines.

7.
Curr Microbiol ; 80(5): 182, 2023 Apr 13.
Artigo em Inglês | MEDLINE | ID: mdl-37046126

RESUMO

HmsB, a temperature-dependent sRNA, promotes biofilm formation by Yersinia pestis, but whether its own expression is regulated by other regulators is still poorly understood. RovM is a global regulator that activates biofilm formation but represses the virulence of Y. pestis. In this work, the results of primer extension, quantitative real-time PCR (qRT-PCR), and LacZ fusion demonstrated that RovM was able to activate hmsB expression. However, the results of electrophoretic mobility shift assay (EMSA) showed that His-RovM did not bind to the upstream DNA region of hmsB. Thus, RovM may exert its regulatory action on hmsB expression in an indirect manner. The data presented here enriched the content of the regulatory circuits that control gene expression in Y. pestis.


Assuntos
Yersinia pestis , Animais , Yersinia pestis/genética , RNA , Arvicolinae , Temperatura , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica
8.
Front Biosci (Landmark Ed) ; 28(2): 40, 2023 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-36866541

RESUMO

BACKGROUND: Antibodies induced by viral infection can not only prevent subsequent virus infection, but can also mediate pathological injury following infection. Therefore, understanding the B-cell receptor (BCR) repertoire of either specific neutralizing or pathological antibodies from patients convalescing from Coronavirus disease 2019 (COVID-19) infection is of benefit for the preparation of therapeutic or preventive antibodies, and may provide insight into the mechanisms of COVID-19 pathological injury. METHODS: In this study, we used a molecular approach of combining 5' Rapid Amplification of cDNA Ends (5'-RACE) with PacBio sequencing to analyze the BCR repertoire of all 5 IgH and 2 IgL genes in B-cells harvested from 35 convalescent patients after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. RESULTS: We observed numerous BCR clonotypes within most COVID-19 patients, but not in healthy controls, which validates the association of the disease with a prototypical immune response. In addition, many clonotypes were found to be frequently shared between different patients or different classes of antibodies. CONCLUSIONS: These convergent clonotypes provide a resource to identify potential therapeutic/prophylactic antibodies, or identify antibodies associated with pathological effects following infection with SARS-CoV-2.


Assuntos
COVID-19 , Humanos , SARS-CoV-2 , Receptores de Antígenos de Linfócitos B/genética , Anticorpos , Linfócitos B
9.
Can J Microbiol ; 68(7): 501-506, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35801716

RESUMO

Yersinia pestis, the causative agent of plague, is one of the most dangerous pathogens in the world. Both the cyclic AMP receptor protein (CRP) and ferric uptake regulator (Fur) are global regulators that control the expression of a great deal of genes involved in a variety of cellular functions in Y. pestis. In this work, two CRP box-like deoxyribonucleic acid (DNA) sequences were detected in the upstream DNA region of fur, suggesting that the transcription of fur might be directly regulated by CRP in Y. pestis. Thus, transcriptional regulation of fur by CRP was investigated by primer extension, quantitative real-time PCR, LacZ fusion, and electrophoretic mobility shift assays. The results demonstrated that CRP was able to bind the regulatory DNA region of fur to activate its transcription. The data presented here not only suggested that the CRP and Fur regulons were bridged together via the direct regulation of fur by CRP, but also provided us a deeper understanding of the transcriptional regulation of fur in Y. pestis.


Assuntos
Proteína Receptora de AMP Cíclico , Yersinia pestis , Proteínas de Bactérias/metabolismo , Proteína Receptora de AMP Cíclico/genética , Proteína Receptora de AMP Cíclico/metabolismo , Regulação Bacteriana da Expressão Gênica , Regiões Promotoras Genéticas , Yersinia pestis/genética , Yersinia pestis/metabolismo
10.
Mol Biomed ; 3(1): 20, 2022 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-35788448

RESUMO

Although the SARS-CoV-2 vaccine has been widely used worldwide, not all individuals can produce neutralization antibodies, so it is still urgent to find and prepare neutralization antibodies for COVID-19 prevention or treatment. In this study, we created a new strategy to effectively obtain neutralizing antibodies or complementary determining region 3 (CDR3) of neutralizing antibodies against SARS-CoV-2. We first predicted and synthesized several B cell epitopes on RBD and adjacent RBD of S protein, then the B cell epitopes were used to prepare affinity chromatography columns respectively and purify the binding IgG from serum samples of convalescent COVID-19 patients. After these IgGs were identified to have neutralizing activity, the peptide sequences of the antigen-binding regions (variable region) of neutralizing antibodies were analyzed by protein mass spectrometry. Subsequently, the B cells from the same individual were sorted and used to obtain their full BCR repertoire by 5' RACE combined with high-throughput of PacBio sequencing method. Then, the peptide sequence of neutralizing antibody variable region by protein mass spectrometry was mapped to the full BCR repertoire and found the full variable region sequence of neutralizing antibodies. Finally, we obtained and synthesized numerous CDR3 peptides of neutralizing antibodies to confirm the neutralizing activity for SARS-CoV-2 infection. Our results indicate that the novel scheme will be suitable for rapid screening of neutralizing antibodies, including screening neutralizing antibodies against SARS-CoV-2 and other pathogenic microorganisms.

11.
Microb Pathog ; 169: 105659, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35760284

RESUMO

Biofilms formed by Yersinia pestis are able to attach to and block flea's proventriculus, which stimulates the transmission of this pathogen from fleas to mammals. In this study, we found that Nlp (YP1143) enhanced biofilm formation by Y. pestis and had regulatory effects on biofilm-associated genes at the transcriptional level. Phenotypic assays, including colony morphology assay, crystal violet staining, and Caenorhabditis elegans biofilm assay, disclosed that Nlp strongly promoted biofilm formation by Y. pestis. Further gene regulation assays showed that Nlp stimulated the expression of hmsHFRS, hmsCDE and hmsB, while had no regulatory effect on the expression of hmsT and hmsP at the transcriptional level. These findings promoted us to gain more understanding of the complex regulatory circuits controlling biofilm formation by Y. pestis.


Assuntos
Peste , Yersinia pestis , Animais , Arvicolinae/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biofilmes , Regulação Bacteriana da Expressão Gênica , Yersinia pestis/metabolismo
12.
Eur J Clin Microbiol Infect Dis ; 40(5): 921-928, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33184753

RESUMO

Serological test is a valuable diagnostic tool for coronavirus disease 2019 (COVID-19). However, considerable improvements to these tests are needed, especially in the detection sensitivity. In this study, six recombinant nucleocapsid and spike proteins of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were prepared and evaluated, including three prokaryotic expression nucleocapsid proteins (rN, rN1, rN2) and three eukaryotic expression spike proteins (rS1, rS-RBD, rS-RBD-mFc). The recombinant proteins with the highest ELISA titers (rS1 and rS-RBD-mFc) were selected to develop a double-antigen sandwich colloidal gold immunochromatography assay (GICA) to detect total antibodies against SARS-CoV-2. The clinical evaluation results showed that the sensitivity and specificity of GICA were 92.09% (419/455) and 99.44% (706/710), respectively. Moreover, a significant number (65.63%, 21/32) of COVID-19 patients with undetectable viral RNA were correctly diagnosed by the GICA method. In conclusion, the eukaryotic expression spike proteins (rS1 and rS-RBD-mFc) are more suitable than the prokaryotic expression nucleocapsid proteins for serological diagnosis of SARS-CoV-2. The proposed GICA for detection of total antibodies could be a powerful complement to the current RNA tests for COVID-19.


Assuntos
Teste Sorológico para COVID-19/métodos , COVID-19/diagnóstico , SARS-CoV-2/isolamento & purificação , Glicoproteína da Espícula de Coronavírus/imunologia , Anticorpos Antivirais/sangue , COVID-19/sangue , Teste de Ácido Nucleico para COVID-19 , Proteínas do Nucleocapsídeo de Coronavírus/genética , Proteínas do Nucleocapsídeo de Coronavírus/imunologia , Humanos , Imunoensaio , Fosfoproteínas/genética , Fosfoproteínas/imunologia , RNA Viral/genética , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , SARS-CoV-2/genética , SARS-CoV-2/imunologia , Sensibilidade e Especificidade , Glicoproteína da Espícula de Coronavírus/genética
13.
Int J Lab Hematol ; 43(2): 329-335, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33099889

RESUMO

INTRODUCTION: Monitoring of laboratory indicators is important for predicting changes in disease severity and clinical outcomes. We aimed to identify the critical predictors that can effectively assess the disease conditions of patients with COVID-19 by analyzing the clinical characteristics and laboratory findings of patients with SARS-CoV-2 infection. METHODS: All consecutive patients (n = 294) with confirmed SARS-CoV-2 infection admitted to the General Hospital of Central Theater Command of the PLA from February 6 to February 21, 2020, were enrolled. These patients were divided into the severe group and the nonsevere group according to disease severity during hospitalization. RESULTS: The median neutrophil-to-lymphocyte ratio (NLR) value of the severe patients was dramatically higher than that of the nonsevere patients (10.4 vs 2.6; P < .001). The NLR value equal to 5 was a boundary value worthy of reference, because more than 80% severe patients had an NLR value greater than 5 and over 80% nonsevere patients had an NLR value less than 5. The NLR value of these COVID-19 patients was positively and respectively correlated with the values of C-reactive protein (R = .5921, P < .001), lactate dehydrogenase (R = .4509, P < .001), procalcitonin (R = .5504, P < .001), fibrinogen (R = .4710, P < .001), and D-dimers (R = .4425, P < .001). However, the NLR value was merely and positively correlated with the interleukin-6 value (R = .3594, P < .05), but had no correlations with the values of interleukin-10, interleukin-4, interleukin-17, interferon-γ, and tumor necrosis factor-α (P > .05). DISCUSSION: Neutrophil-to-lymphocyte ratio is a critical predictor for assessment of disease severity in patients with COVID-19, and it has a close relation with the laboratory indicators related to disease conditions.


Assuntos
Proteína C-Reativa/metabolismo , COVID-19/diagnóstico , Produtos de Degradação da Fibrina e do Fibrinogênio/metabolismo , Neutrófilos/patologia , SARS-CoV-2/patogenicidade , Linfócitos T/patologia , Adolescente , Adulto , Fatores Etários , Idoso , Biomarcadores/sangue , COVID-19/sangue , COVID-19/patologia , COVID-19/virologia , Feminino , Fibrinogênio/metabolismo , Humanos , Interleucina-6/sangue , L-Lactato Desidrogenase/sangue , Masculino , Pessoa de Meia-Idade , Neutrófilos/imunologia , Neutrófilos/virologia , Valor Preditivo dos Testes , Pró-Calcitonina/sangue , Estudos Retrospectivos , SARS-CoV-2/imunologia , Índice de Gravidade de Doença , Fatores Sexuais , Linfócitos T/imunologia , Linfócitos T/virologia
14.
J Clin Virol ; 130: 104576, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32763810

RESUMO

BACKGROUND: The unsatisfactory accuracy and capacity of real time RT-PCR depends on several unavoidable reasons, which cannot meet the demands for COVID-19 diagnosis. METHODS: 206 serum samples were collected from patients who were treated in the General Hospital of the Central Theater Command of the PLA between January 18 and April 4, 2020. 270 serum samples from healthy blood donors were used as control. IgM and total antibodies (Ab) against SARS-CoV-2 were detected by Chemiluminescence Microparticle Immunoassay (CMIA). RESULTS: Among the 206 patients, the positive rate of IgM and Ab were 149/206 (72.3 %) and 187/206 (90.8 %), respectively. And the specificity of IgM and Ab detection were 99.3 % and 98.9 %, respectively. The sensitivity of CMIA for Ab detection was significantly higher than that of IgM. An increase of the positive rate and S/CO value for detecting IgM and Ab accompanied with the increasing of days post-disease onset (d.p.o.) were observed. The positive rate of Ab detected by CMIA increased rapidly after 7 d.p.o., while that of IgM was obviously increased after 14 d.p.o.. In addition, the age and gender of these patients did not affect the seroconversion and titer of antibodies during the whole course. The disease-severity of patients had no effect on the seroconversion of antibodies. However, the critical patients possessed a much higher antibody titers than the no-critical cases after 14 d.p.o.. CONCLUSIONS: The CMIA can provide important complementation to nucleic acid assay and help to enhance the accuracy and capacity of diagnosis of SARS-CoV-2 infection.


Assuntos
Anticorpos Antivirais/sangue , Técnicas de Laboratório Clínico/métodos , Infecções por Coronavirus/diagnóstico , Imunoensaio/métodos , Pneumonia Viral/diagnóstico , Adulto , Idoso , Betacoronavirus , COVID-19 , Teste para COVID-19 , Vacinas contra COVID-19 , Infecções por Coronavirus/imunologia , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Medições Luminescentes , Masculino , Pessoa de Meia-Idade , Pandemias , Pneumonia Viral/imunologia , SARS-CoV-2 , Sensibilidade e Especificidade , Soroconversão
15.
Microbes Infect ; 22(4-5): 206-211, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32425648

RESUMO

In this study, we aimed to evaluate the diagnostic value of serological assay for SARS-CoV-2. A newly-developed ELISA assay for IgM and IgG antibodies against N protein of SARS-CoV-2 was used to screen the serums of 238 admitted hospital patients between February 6 and February 14, 2020 with confirmed or suspected SARS-CoV-2. SARS-CoV-2 RNA was detected on pharyngeal swab specimens using real time RT-PCR. 194 (81.5%) of the serums were detected to be antibody (IgM and/or IgG) positive, significantly higher than the positive rate of viral RNA (64.3%). There was no difference in the positive rate of antibodies between the confirmed patients (83.0%, 127/153) and the suspected patients (78.8%, 67/85), whose nucleic acid tests were negative. The antibody positive rates were very low in the first five days after initial onset of symptoms, and then rapidly increased as the disease progressed. After 10 days, the antibody positive rates jumped from below 50% to over 80%. However, the positive rates of viral RNA maintained above 60% in the first 11 days after initial onset of symptoms, and then rapidly decreased. Overall, the suspected patients were most likely infected by SARS-CoV-2. Before the 11th day after initial onset of symptoms, nucleic acid test is key for confirmation of viral infection. The combination of serological assay can greatly improve the diagnostic efficacy. After the 11th day post-disease onset, the diagnosis for viral infection should be majorly dependent on serological assay.


Assuntos
Anticorpos Antivirais/sangue , Betacoronavirus , Infecções por Coronavirus/diagnóstico , Infecções por Coronavirus/virologia , Pacientes Internados , Pneumonia Viral/diagnóstico , Pneumonia Viral/virologia , Testes Sorológicos , Adulto , Idoso , COVID-19 , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Masculino , Pessoa de Meia-Idade , Pandemias , RNA Viral/sangue , SARS-CoV-2
16.
J Clin Microbiol ; 58(6)2020 05 26.
Artigo em Inglês | MEDLINE | ID: mdl-32229605

RESUMO

At present, PCR-based nucleic acid detection cannot meet the demands for coronavirus infectious disease (COVID-19) diagnosis. Two hundred fourteen confirmed COVID-19 patients who were hospitalized in the General Hospital of Central Theater Command of the People's Liberation Army between 18 January and 26 February 2020 were recruited. Two enzyme-linked immunosorbent assay (ELISA) kits based on recombinant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid protein (rN) and spike protein (rS) were used for detecting IgM and IgG antibodies, and their diagnostic feasibility was evaluated. Among the 214 patients, 146 (68.2%) and 150 (70.1%) were successfully diagnosed with the rN-based IgM and IgG ELISAs, respectively; 165 (77.1%) and 159 (74.3%) were successfully diagnosed with the rS-based IgM and IgG ELISAs, respectively. The positive rates of the rN-based and rS-based ELISAs for antibody (IgM and/or IgG) detection were 80.4% and 82.2%, respectively. The sensitivity of the rS-based ELISA for IgM detection was significantly higher than that of the rN-based ELISA. We observed an increase in the positive rate for IgM and IgG with an increasing number of days post-disease onset (d.p.o.), but the positive rate of IgM dropped after 35 d.p.o. The positive rate of rN-based and rS-based IgM and IgG ELISAs was less than 60% during the early stage of the illness, 0 to 10 d.p.o., and that of IgM and IgG was obviously increased after 10 d.p.o. ELISA has a high sensitivity, especially for the detection of serum samples from patients after 10 d.p.o., so it could be an important supplementary method for COVID-19 diagnosis.


Assuntos
Betacoronavirus/imunologia , Técnicas de Laboratório Clínico/métodos , Infecções por Coronavirus/imunologia , Infecções por Coronavirus/virologia , Ensaio de Imunoadsorção Enzimática/métodos , Pneumonia Viral/imunologia , Pneumonia Viral/virologia , Glicoproteína da Espícula de Coronavírus/imunologia , COVID-19 , Teste para COVID-19 , Infecções por Coronavirus/diagnóstico , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Pandemias , SARS-CoV-2
17.
Nat Commun ; 11(1): 281, 2020 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-31941912

RESUMO

Yersinia pestis is transmitted from fleas to rodents when the bacterium develops an extensive biofilm in the foregut of a flea, starving it into a feeding frenzy, or, alternatively, during a brief period directly after feeding on a bacteremic host. These two transmission modes are in a trade-off regulated by the amount of biofilm produced by the bacterium. Here by investigating 446 global isolated Y. pestis genomes, including 78 newly sequenced isolates sampled over 40 years from a plague focus in China, we provide evidence for strong selection pressures on the RNA polymerase ω-subunit encoding gene rpoZ. We demonstrate that rpoZ variants have an increased rate of biofilm production in vitro, and that they evolve in the ecosystem during colder and drier periods. Our results support the notion that the bacterium is constantly adapting-through extended phenotype changes in the fleas-in response to climate-driven changes in the niche.


Assuntos
Proteínas de Bactérias/genética , Peste/microbiologia , Sifonápteros/microbiologia , Yersinia pestis/fisiologia , Animais , Biofilmes , Evolução Biológica , China , Clima , RNA Polimerases Dirigidas por DNA/genética , Reservatórios de Doenças , Ecossistema , Infestações por Pulgas , Variação Genética , Genoma Bacteriano , Interações Hospedeiro-Parasita , Interações Hospedeiro-Patógeno , Marmota/parasitologia , Fenótipo , Filogenia , Sciuridae/parasitologia , Seleção Genética , Sifonápteros/fisiologia , Yersinia pestis/genética
18.
Infect Immun ; 86(6)2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29610260

RESUMO

Recent studies revealed that acetylation is a widely used protein modification in prokaryotic organisms. The major protein acetylation acetyltransferase YfiQ and the sirtuin-like deacetylase CobB have been found to be involved in basic physiological processes, such as primary metabolism, chemotaxis, and stress responses, in Escherichia coli and Salmonella However, little is known about protein acetylation modifications in Yersinia pestis, a lethal pathogen responsible for millions of human deaths in three worldwide pandemics. Here we found that Yp_0659 and Yp_1760 of Y. pestis encode the major protein acetylation acetyltransferase YfiQ and the sirtuin-like deacetylase CobB, respectively, which can acetylate and deacetylate PhoP enzymatically in vitro Protein acetylation impairment in cobB and yfiQ mutants greatly decreased bacterial tolerance to cold, hot, high-salt, and acidic environments. Our comparative transcriptomic data revealed that the strongly decreased tolerance to stress stimuli was probably related to downregulation of the genes encoding the heat shock proteins (HtpG, HslV, HslR, and IbpA), cold shock proteins (CspC and CspA1), and acid resistance proteins (HdeB and AdiA). We found that the reversible acetylation mediated by CobB and YfiQ conferred attenuation of virulence, probably partially due to the decreased expression of the psaABCDEF operon, which encodes Psa fimbriae that play a key role in virulence of Y. pestis This is the first report, to our knowledge, on the roles of protein acetylation modification in stress responses, biofilm formation, and virulence of Y. pestis.


Assuntos
Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica/fisiologia , Sirtuínas/metabolismo , Yersinia pestis/metabolismo , Acetiltransferases , Proteínas de Bactérias/genética , Biofilmes/crescimento & desenvolvimento , Deleção de Genes , Células HeLa , Humanos , Concentração de Íons de Hidrogênio , Sirtuínas/genética , Cloreto de Sódio , Estresse Fisiológico , Temperatura , Virulência , Yersinia pestis/genética , Yersinia pestis/fisiologia
19.
Infect Immun ; 85(8)2017 08.
Artigo em Inglês | MEDLINE | ID: mdl-28533472

RESUMO

Pathogenic yersiniae harbor a type III secretion system (T3SS) that injects Yersinia outer protein (Yop) into host cells. YopK has been shown to control Yop translocation and prevent inflammasome recognition of the T3SS by the innate immune system. Here, we demonstrate that YopK inhibits bacterial adherence to host cells by binding to the extracellular matrix adaptor protein matrilin-2 (MATN2). YopK binds to MATN2, and deleting amino acids 91 to 124 disrupts binding of YopK to MATN2. A yopK null mutant exhibits a hyperadhesive phenotype, which could be responsible for the established Yop hypertranslocation phenotype of yopK mutants. Expression of YopK, but not YopKΔ91-124, in a yopK mutant restored the wild-type phenotypes of adhesion and Yop translocation, suggesting that binding to MATN2 might be essential for YopK to inhibit bacterial adhesion and negatively regulate Yop translocation. A green fluorescent protein (GFP)-YopK fusion specifically binds to the endogenous MATN2 on the surface of HeLa cells, whereas GFP-YopKΔ91-124 cannot. Addition of purified YopK protein during infection decreased adhesion of Y. pestis to HeLa cells, while YopKΔ91-124 protein showed no effect. Taking these results together, we propose a model that the T3SS-secreted YopK hinders bacterial adhesion to HeLa cells by binding to MATN2, which is ubiquitously exposed on eukaryotic cells.


Assuntos
Aderência Bacteriana , Proteínas da Membrana Bacteriana Externa/metabolismo , Yersinia pestis/metabolismo , Animais , Proteínas da Membrana Bacteriana Externa/genética , Translocação Bacteriana , Células HeLa , Humanos , Proteínas Matrilinas/metabolismo , Camundongos , Mutação , Fagocitose , Fenótipo , Sistemas de Secreção Tipo III/metabolismo , Yersinia pestis/química , Yersinia pestis/genética , Yersinia pestis/patogenicidade
20.
Int J Med Microbiol ; 307(1): 64-74, 2017 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-27876297

RESUMO

Pneumonic plague is the most deadly form of infection caused by Yersinia pestis and can progress extremely fast. However, our understanding on the host transcriptomic response to pneumonic plague is insufficient. Here, we used RNA-sequencing technology to analyze transcriptomic responses in mice infected with fully virulent strain 201 or EV76, a live attenuated vaccine strain lacking the pigmentation locus. Approximately 600 differentially expressed genes (DEGs) were detected in lungs from both 201- and EV76-infected mice at 12h post-infection (hpi). DEGs in lungs of 201-infected mice exceeded 2000 at 48hpi, accompanied by sustained large numbers of DEGs in the liver and spleen; however, limited numbers of DEGs were detected in those organs of EV-infected mice. Remarkably, DEGs in lungs were significantly enriched in critical immune responses pathways in EV76-infected but not 201-infected mice, including antigen processing and presentation, T cell receptor signaling among others. Pathological and bacterial load analyses confirmed the rapid systemic dissemination of 201-infection and the confined EV76-infection in lungs. Our results suggest that fully virulent Y. pestis inhibits both the innate and adaptive immune responses that are substantially stimulated in a self-limited infection, which update our holistic views on the transcriptomic response to pneumonic plague.


Assuntos
Imunidade Adaptativa , Perfilação da Expressão Gênica , Interações Hospedeiro-Patógeno , Evasão da Resposta Imune , Imunidade Inata , Peste/patologia , Yersinia pestis/patogenicidade , Animais , Carga Bacteriana , Modelos Animais de Doenças , Feminino , Fígado/microbiologia , Fígado/patologia , Pulmão/microbiologia , Pulmão/patologia , Camundongos , Baço/microbiologia , Baço/patologia , Fatores de Tempo , Yersinia pestis/imunologia
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