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1.
Appl Opt ; 63(3): 757-761, 2024 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-38294388

RESUMO

A helical structural support scheme is proposed to mechanically support dielectric layers in a hollow-core terahertz Bragg waveguide by means of an axially rotating wrap-around strip structure. The helical-strip supported waveguide samples are fabricated using 3D printing technology, and the waveguide samples are experimentally tested using a terahertz time-domain spectroscopy system. The results show that choosing a suitable helix period can obtain loss characteristics close to those of an ideal Bragg waveguide, with a low transmission loss of less than 0.097 dB/m in the range of 0.57-0.58 THz.

2.
Biosens Bioelectron ; 248: 115968, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38150799

RESUMO

Screening for high-risk human papillomavirus (HPV) infection is one of the most important preventative measures for cervical cancer. However, fast, convenient, and low-cost HPV detection remains challenging, especially in resource-limited settings. Here, we report a portable all-in-one device (PAD) for point-of-care testing (POCT) for HPV16 and HPV18 DNA in cervical swabs. The PAD was engineered to integrate modules for extraction-free sample lysis, loop-mediated isothermal amplification (LAMP) with lyophilized reagent beads, and real-time colorimetric signal sensing into a single miniaturized device, considerably shortening the sample-to-result time to 15 min. The precision liquid handling in the completely sealed microfluidic chip is achieved by a uniquely designed pressure-balanced automatic liquid flow mechanism, thereby eliminating the need for manual manipulation of liquids and thus the risk of biohazards. The PAD employs an improved real-time colorimetric LAMP (rcLAMP) assay with a limit of detection (LOD) of 1 copy/µL, enabled by enhanced assay chemistry to maximize the reaction kinetics. To validate this device for clinical application, we tested 206 clinical cervical swab samples and obtained a sensitivity of 92.1% and a specificity of 99.0%. This custom PAD enabled by microfluidic and electronic engineering techniques can be configured for the simultaneous detection of HPV16 and HPV18 or other pathogens in point-of-care applications.


Assuntos
Técnicas Biossensoriais , Infecções por Papillomavirus , Feminino , Humanos , Microfluídica , Papillomavirus Humano 16/genética , Papillomavirus Humano 18/genética , Colorimetria/métodos , Infecções por Papillomavirus/diagnóstico , Técnicas de Amplificação de Ácido Nucleico/métodos , Testes Imediatos , DNA Viral/genética , Dispositivos Lab-On-A-Chip , Sensibilidade e Especificidade
3.
Ann Transl Med ; 10(8): 471, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35571399

RESUMO

Background: Colposcopy is a critical component of cervical cancer screening services, but the accuracy of colposcopy varies greatly due to the lack of standardized training for colposcopists and pathologists. Thus, to improve the accuracy of colposcopy in the detection of cervical lesions intelligently is urgent. Here, we explored the sensitivity and specificity of a bioimpedance-based neural network algorithm in distinguishing normal and precancerous cervical tissues. Methods: Bioimpedance data were collected using a bioimpedance analyzer (Mscan1.0B, Sealand Technology, Chengdu, China) from the cervices of 102 female patients with abnormal cervical cytology (≥atypical squamous cells of undetermined significance) who required further colposcopy. Finally, the data of 106 samples from 37 patients were included, among which 85were used as the training set and 21 as the validation set. Using the biopsy pathology at each locus as the gold standard, the sensitivity, specificity, predictive value, likelihood ratio, and false positive and false negative rates of the bioimpedance-based neural network in identifying the normal and precancerous cervical tissues were calculated. Results: The bioimpedance method had a sensitivity of 0.90 [95% confidence interval (CI): 0.54 to 0.99], specificity of 0.82 (95% CI: 0.48 to 0.97), positive predictive value of 0.82 (95% CI: 0.48 to 0.97), and a negative predictive value of 0.90 (95% CI: 0.54 to 0.99) in distinguishing normal and precancerous cervical tissues. The Kappa value was 0.72. Conclusions: The bioimpedance method was an intelligent method with relative good sensitivity and specificity in distinguishing benign cervical tissue and precancerous lesions and can therefore be used as an adjunctive test to colposcopy to improve the detection of cervical lesions.

4.
J Transl Med ; 20(1): 12, 2022 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-34980148

RESUMO

BACKGROUND: The status of vaginal microbiota in persistent high-risk human papilloma virus (HR-HPV) infection is unclear. The present work aimed to identify the vaginal microbiota of persistent HPV infection and explore the possible underlying microbiota factors. METHODS: A total of 100 women were recruited in this study, of which 28 presented HR-HPV persistent infection (P group), 30 showed clearance of any subtype of HR-HPV (C group), and 42 had no history of any HR-HPV infection (NC group). The vaginal microbiota and the community structure of the three groups were compared based on the 16S rRNA sequencing of the V3-V4 region. The microbiota diversity and differential analysis were carried out to detect the potential factors associated with HR-HPV infection. RESULTS: P and C groups showed an increase of Firmicutes and Actinobacteriota but a decrease in Proteobacteria compared to the NC group. The Chao1 index indicated that the microbial richness of the NC group was greater than C group (P < 0.05).The principal co-ordinate analysis(PCoA) revealed differences between the NC and P/C groups.The linear discriminant analysis effect size (LEfSe) method indicated that Proteobacteria phylum was significantly different in the mean relative abundance in the NC group,but the P and C groups did not show such indicative taxa. The Wilcox rank-sum test indicated that the Bifidobacterium (P = 0.002) and Lactobacillus (P = 0.005) of the C group were in a high mean relative abundance compared to the NC group. CONCLUSIONS: The persistent HR-HPV infection is associated with dysbiosis of the vaginal microbiota. Microbiome regulation with Bifidobacteria and Lactobacillus may affect the clearance of HPV.


Assuntos
Microbiota , Infecções por Papillomavirus , Disbiose , Feminino , Humanos , Papillomaviridae , RNA Ribossômico 16S/genética , Vagina/microbiologia
5.
J Med Virol ; 91(1): 155-160, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30168582

RESUMO

Coxsackievirus A16 (CV-A16) commonly causes mild symptoms, but severe diseases, such as aseptic meningitis, encephalitis, and even fatal cases, have been reported. Thirteen CV-A16 strains were isolated from patients with severe hand, foot, and mouth disease in Yunnan, Southwest China, from 2009 to 2015. Subgenotype B1a and B1b of CV-A16 were predominantly circulating the region with B1b the predominant strain in recent years. The mean rate of nucleotide substitution based on the VP1 gene sequence was 4.545 × 10 -3 substitution per site per year from 2009 to 2015. These results may help in understanding the genetic diversity of CV-A16 and develop a CV-A16 vaccine.


Assuntos
Enterovirus/classificação , Enterovirus/isolamento & purificação , Genótipo , Doença de Mão, Pé e Boca/patologia , Doença de Mão, Pé e Boca/virologia , Criança , Pré-Escolar , China/epidemiologia , Enterovirus/genética , Doença de Mão, Pé e Boca/epidemiologia , Humanos , Taxa de Mutação , Proteínas Estruturais Virais/genética
6.
Arch Virol ; 158(9): 1889-94, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23553454

RESUMO

Co-infection of hepatitis B virus (HBV) and/or hepatitis C virus (HCV) with human immunodeficiency virus (HIV) has an adverse effect on liver disease progression. This study investigated the prevalence of HBV and/or HCV co-infection in HIV-infected patients in Central China. A total of 978 HIV-infected patients from Hunan Province were enrolled. HBV serum markers, anti-hepatitis-C-virus antibody (anti-HCV), HBV DNA, and HBV genotypes were analyzed. The prevalence of hepatitis B surface antigen (HBsAg) and anti-HCV in HIV-infected patients was 19.4 % and 62.4 %, respectively. The prevalence of anti-HCV in HIV-positive intravenous drug users was 93.6 %. Among HBsAg-positive patients, 88.1 % were found to have at least one HBV serum marker. The rates of HIV mono-infection, HBV/HIV dual infection, HCV/HIV dual infection, and HBV/HCV/HIV triple infection were 30.4 %, 7.2 %, 50.2 %, and 12.2 %, respectively. Antibody to HBsAg (Anti-HBs) was more common in anti-HCV-positive than anti-HCV-negative patients (53.3 % vs 40.2 %, P = 0.000), but isolated hepatitis B core antibody (anti-HBc) was more common in anti-HCV-negative than anti-HCV-positive patients (24.2 % vs 12.3 %, P = 0.000). Hepatitis B e antigen (HBeAg) and sexual transmission were independent risk factors for active HBV replication. Intravenous drug use and male sex were independent risk factors, but old age and presence of HBeAg were independent protective factors for anti-HCV. Co-infection of HBV and/or HCV with HIV infection is common in central China. HCV status is associated with anti-HBs and isolated anti-HBc in co-infected patients.


Assuntos
Coinfecção/epidemiologia , Infecções por HIV/complicações , Infecções por HIV/epidemiologia , Vírus da Hepatite B/imunologia , Adulto , China/epidemiologia , Coinfecção/virologia , Feminino , Infecções por HIV/virologia , Hepacivirus/imunologia , Hepatite B/complicações , Hepatite B/epidemiologia , Antígenos de Superfície da Hepatite B/sangue , Vírus da Hepatite B/classificação , Vírus da Hepatite B/genética , Hepatite C/complicações , Hepatite C/epidemiologia , Hepatite C/imunologia , Anticorpos Anti-Hepatite C/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Abuso de Substâncias por Via Intravenosa/complicações , Abuso de Substâncias por Via Intravenosa/epidemiologia , Abuso de Substâncias por Via Intravenosa/imunologia
7.
Microbiology (Reading) ; 155(Pt 11): 3622-3631, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19643764

RESUMO

OmpR has been demonstrated to negatively regulate the expression of the flagellar master operon flhDC in a wide variety of bacterial species. Here we report the positive regulation of flhDC expression by OmpR in Yersinia pseudotuberculosis. A sigma(70)-dependent promoter was identified by primer extension analysis and an active region with two conserved OmpR-binding sites around the flhDC promoter was confirmed. To confirm the regulation of flhDC expression by OmpR, flhDC as well as the downstream flagellar genes fliA, flgD, flgA, flgM, fliC and flaA were fused to lacZ, and decreased expression of all these genes in an ompR mutant (Delta ompR) was detected. Furthermore, Delta ompR was defective in bacterial motility and flagella synthesis. This defect was due to the low level of expression of flhDC in Delta ompR since overproduction of FlhDC in Delta ompR restored bacterial motility. The importance of two conserved OmpR-binding sites around the flhDC promoter region in the regulation of flhDC expression by OmpR was demonstrated by the fact that mutation of either one or both sites significantly decreased the promoter activity in the wild-type but not in Delta ompR. The binding of OmpR to these two sites was also demonstrated by DNA mobility shift assay. The possible mechanism underlying this positive regulation in Y. pseudotuberculosis is discussed. To our knowledge, this is the first report to demonstrate that OmpR positively regulates flhDC expression.


Assuntos
Proteínas de Bactérias/metabolismo , Óperon , Transativadores/metabolismo , Yersinia pseudotuberculosis/genética , Proteínas de Bactérias/genética , Flagelos/genética , Flagelos/metabolismo , Regulação Bacteriana da Expressão Gênica , Mutação , Regiões Promotoras Genéticas , Transativadores/genética , Sítio de Iniciação de Transcrição , Yersinia pseudotuberculosis/metabolismo
8.
Wei Sheng Wu Xue Bao ; 49(4): 417-22, 2009 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-19621626

RESUMO

Motility was considered to be closely related with biofilm formation positively for a long time because the ability of biofilm formation would be decreased in the motility-defective bacteria. Moreover,the results of defective mutants of flagella and some other regulated proteins suggested that the relationship between motility and biofilm was diverse in different bacteria. Factors other than motility could influence the development of biofilms as well. Namely, motility is not the only determining factor for biofilm formation. Here,we described bacterial biofilm and motility in detail and evaluated their correlation.


Assuntos
Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Fenômenos Fisiológicos Bacterianos , Biofilmes/crescimento & desenvolvimento , Flagelos/metabolismo , Modelos Biológicos
9.
Microbiology (Reading) ; 155(Pt 8): 2522-2531, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19443542

RESUMO

Yersinia pseudotuberculosis is an enteric bacterium which must overcome the acidic stress in host organs for successful colonization, but how this bacterium survives in acidic conditions remains largely unknown. In the present study, the importance of OmpR in acid survival of Y. pseudotuberculosis YpIII was confirmed by the fact that mutation of ompR (strain DeltaompR) greatly reduced cell survival at pH 4.5 or lower. To characterize the regulatory role of OmpR in this acid survival process, proteomic analysis was carried out to compare YpIII at pH 7.0 and pH 4.5 with DeltaompR at pH 7.0, and urease components were revealed to be the main targets for OmpR regulation. Addition of urea to the culture medium also enhanced acid survival of YpIII but not DeltaompR and urease activity was significantly induced by acid in YpIII but not in DeltaompR. Each of the seven components of the YpIII urease gene cluster was fused to a lacZ reporter and their expression was dramatically decreased in a DeltaompR background; this supports the notion that OmpR positively regulates urease expression. Furthermore, gel shift analysis revealed that OmpR binds to the deduced promoter regions of three polycistronic transcriptional units (ureABC, ureEF and ureGD) in the urease cluster, suggesting that the regulation of OmpR to urease components is direct. Taken together, these data strongly suggest that OmpR activates urease expression to enhance acid survival in Y. pseudotuberculosis.


Assuntos
Ácidos/metabolismo , Proteínas de Bactérias/metabolismo , Transativadores/metabolismo , Urease/biossíntese , Yersinia pseudotuberculosis/fisiologia , DNA Bacteriano/genética , Eletroforese em Gel Bidimensional , Ensaio de Desvio de Mobilidade Eletroforética , Regulação Bacteriana da Expressão Gênica , Concentração de Íons de Hidrogênio , Família Multigênica , Regiões Promotoras Genéticas , Estresse Fisiológico , Transcrição Gênica , Urease/genética
10.
Microbiology (Reading) ; 155(Pt 6): 1890-1900, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19383707

RESUMO

We describe here the functional characterization of the flgM gene in Yersinia pseudotuberculosis. Direct interaction of FlgM with the alternative sigma factor sigma(28) (FliA) was first confirmed. A conserved region in the C-terminus of FlgM was found which included the sigma(28) binding domain. By site-directed mutagenesis, bacterial two-hybrid analysis and Western blotting, the primary FlgM binding sites with sigma(28) were shown to be Ile85, Ala86 and Leu89. A role for FlgM in swimming motility was demonstrated by inactivation of flgM and subsequent complementation in trans. Transcriptional fusion analyses showed differential gene expression of flhDC, fliA, flgM and fliC in the fliA and flgM mutants compared with the wild-type. flhDC expression was not influenced by sigma(28) or FlgM while fliA expression was abolished in the fliA mutant and considerably reduced in the flgM mutant when compared to the wild-type, indicating that both FliA and FlgM can activate fliA transcription. Conversely, flgM transcription was higher in the fliA mutant when compared to the wild-type, suggesting that flgM transcription was repressed by sigma(28). Interestingly, fliC expression was markedly increased in the flgM mutant, suggesting a negative regulatory role for FlgM in fliC expression. The transcription of other sigma-dependent genes (cheW, flgD, flaA, csrA and fliZ) was also examined in fliA and flgM mutant backgrounds and this revealed that other sigma-factors apart from sigma(28) may be involved in flagellar biogenesis in Y. pseudotuberculosis. Taking together the motility phenotypes and effects of flgM mutation on the regulation of these key motility genes, we propose that the mechanisms regulating flagellar biogenesis in Y. pseudotuberculosis may differ from those described for other bacteria.


Assuntos
Proteínas de Bactérias/fisiologia , Flagelos/metabolismo , Yersinia pseudotuberculosis/metabolismo , Sequência de Aminoácidos , Aminoácidos/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Sequência Conservada/fisiologia , Proteínas de Escherichia coli/metabolismo , Flagelos/genética , Flagelina , Regulação Bacteriana da Expressão Gênica , Teste de Complementação Genética , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Regiões Promotoras Genéticas , Ligação Proteica , Fator sigma/metabolismo , Transcrição Gênica , Yersinia pseudotuberculosis/genética
11.
Sci China C Life Sci ; 50(6): 814-21, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17973093

RESUMO

The flagella master regulatory gene flhDC of Yersinia pseudotuberculosis serotype III (YPIII) was mutated by deleting the middle region and replaced by a tetracycline resistant gene, and the subsequent mutant strain named YPIIIDeltaflhDC was obtained. Swimming assay showed that the swimming motility of the mutant strain was completely abolished. The promoter region of the flagella second-class regulatory gene fliA was fused with the lux box, and was conjugated with the mutant and the parent strains respectively for the first cross. LUCY assay result demonstrated that flhDC regulated the expression of fliA in YPIII as reported in E. coli. Biofilm formation of the mutant strain on abiotic and biotic surfaces was observed and quantified. The results showed that mutation of flhDC decreased biofilm formation on both abiotic and biotic surfaces, and abated the infection on Caenorhabdtis elegans. Our results suggest that mutation of the flagella master regulatory gene flhDC not only abolished the swimming motility, but also affected biofilm formation of YPIII on different surfaces. The new function of flhDC identified in this study provides a novel viewpoint for the control of bacterial biofilm formation.


Assuntos
Proteínas de Bactérias/genética , Biofilmes , Proteínas de Ligação a DNA/genética , Transativadores/genética , Yersinia pseudotuberculosis/genética , Proteínas de Bactérias/fisiologia , Sequência de Bases , Proteínas de Ligação a DNA/fisiologia , Flagelos/genética , Flagelos/metabolismo , Regulação Bacteriana da Expressão Gênica/fisiologia , Deleção de Sequência , Transativadores/fisiologia , Yersinia pseudotuberculosis/metabolismo
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