OBJECTIVE: Pseudomonas aeruginosa( P. aeruginosa) is a prevalent pathogenic bacterium involved in meningitis; however, the virulence factors contributing to this disease remain poorly understood. METHODS: The virulence of the P. aeruginosa A584, isolated from meningitis samples, was evaluated by constructing in vitro blood-brain barrier and in vivo systemic infection models. qPCR, whole-genome sequencing, and drug efflux assays of A584 were performed to analyze the virulence factors. RESULTS: Genomic sequencing showed that A584 formed a phylogenetic cluster with the reference strains NY7610, DDRC3, Pa58, and Pa124. Its genome includes abundant virulence factors, such as hemolysin, the Type IV secretion system, and pyoverdine. A584 is a multidrug-resistant strain, and its wide-spectrum resistance is associated with enhanced drug efflux. Moreover, this strain caused significantly more severe damage to the blood-brain barrier than the standard strain, PAO1. qPCR assays further revealed the downregulation of the blood-brain barrier-associated proteins Claudin-5 and Occludin by A584. During systemic infection, A584 exhibited a higher capacity of brain colonization than PAO1 (37.1 × 10 ⁶ CFU/g brain versus 2.5 × 10 ⁶ CFU/g brain), leading to higher levels of the pro-inflammatory factors IL-1β and TNF-α. CONCLUSION This study sheds light on the virulence factors of P. aeruginosa involved in meningitis.
Pseudomonas aeruginosa/genetics* ; Virulence Factors/metabolism* ; Animals ; Virulence ; Mice ; Pseudomonas Infections/microbiology* ; Blood-Brain Barrier/microbiology* ; Humans ; Female

OBJECTIVE: To evaluate the efficacy of cis-2-dodecenoic acid (BDSF) in the treatment and prevention of vaginal candidiasis in vivo. METHODS: The activities of different concentrations of BDSF against the virulence factors of Candida albicans (C. albicans) were determined in vitro. An experimental mouse model of Candida vaginitis was treated with 250 μmol/L BDSF. Treatment efficiency was evaluated in accordance with vaginal fungal burden and inflammation symptoms. RESULTS: In vitro experiments indicated that BDSF attenuated the adhesion and damage of C. albicans to epithelial cells by decreasing phospholipase secretion and blocking filament formation. Treatment with 30 μmol/L BDSF reduced the adhesion and damage of C. albicans to epithelial cells by 36.9% and 42.3%, respectively. Treatment with 200 μmol/L BDSF completely inhibited phospholipase activity. In vivo mouse experiments demonstrated that BDSF could effectively eliminate vaginal infection and relieve inflammatory symptoms. Four days of treatment with 250 μmol/L BDSF reduced vaginal fungal loads by 6-fold and depressed inflammation. Moreover, BDSF treatment decreased the expression levels of the inflammatory chemokine-associated genes MCP-1 and IGFBP3 by 2.5- and 2-fold, respectively. CONCLUSION BDSF is a novel alternative drug that can efficiently control vaginal candidiasis by inhibiting the virulence factors of C. albicans.
Animals ; Candida albicans ; drug effects ; metabolism ; pathogenicity ; physiology ; Candidiasis, Vulvovaginal ; drug therapy ; genetics ; immunology ; microbiology ; Chemokine CCL2 ; genetics ; immunology ; Disease Models, Animal ; Fatty Acids, Monounsaturated ; administration & dosage ; Female ; Fungal Proteins ; genetics ; metabolism ; Humans ; Insulin-Like Growth Factor Binding Protein 3 ; genetics ; immunology ; Mice ; Virulence ; drug effects ; Virulence Factors ; genetics ; metabolism

To determine the lysis spectrum of Yersinia enterocolitica bacteriophage phiYe-F10 and to analyze the relationship between the lysis ability of phiYe-F10 and the virulence gene of Yersinia enterocolitica. To observe the lysis ability of the phage phiYe-F10 to the different Yersinia strains with the double-layer technique. The strains used in this study including 213 of Yersinia enterocolitica and 36 of Yersinia pseudotuberculosis and 1 of Yersinia pestis. The virulence genes of these Yersinia enterocolitica (attachment invasion locus (ail) and enterotoxin (ystA, ystB) and yersinia adhesin A (yadA), virulence factor (virF), specific gene for lipopolysaccharide O-side chain of serotype O : 3 (rfbc) were all detected. Among the 213 Yersinia enterocolitica, 84 strains were O : 3 serotype (78 strains with rfbc gene), 10 were serotype O : 5, 13 were serotype O : 8, 34 were serotype O : 9 and 72 were other serotypes. Of these, 77 were typical pathogenic Yersinia enterocolitica harboring with virulence plasmid (ail+, ystA+, ystB-, yadA+, virF+), and 15 were pathogenic bacterial strains deficiency virulence plasmid (ail+, ystA+, ystB-, yadA-, virF-) and the rest 121 were non pathogenic genotype strains. PhiYe-F10 lysed the 71 serotype O : 3 Yersinia enterocolitica strains which were all carried with rfbc+, including 52 pathogenic Yersinia enterocolitica, 19 nonpathogenic Y. enterocolitica. The phiYe-F10 can not lysed serotype O : 5, O : 9 and other serotype Y. enterocolitica, the lysis rate of serotype O : 3 was as high as 84.5%. The phiYe-F10 can not lysed Yersinia pseudotuberculosis and Yersinia pestis. Yersinia phage phiYe-F10 is highly specific for serotype O : 3 Yersinia enterocolitic at 25 degrees C, which showed a typical narrow lysis spectrum. Phage phiYe-F10 can lysed much more pathogenic Y. enterocolitica than nonpathogenic Y. enterocolitica.
Bacterial Proteins ; genetics ; metabolism ; Bacteriophages ; genetics ; isolation & purification ; physiology ; Host Specificity ; Virulence Factors ; genetics ; metabolism ; Yersinia enterocolitica ; genetics ; metabolism ; virology

OBJECTIVETo observe the dynamic changes of membrane-bound proton-translocating ATPase (F-ATPase) in the development of dental caries, the expression of Streptococcus mutans F-ATPase under different pH concentrations and during the development of dental caries is analyzed.

METHODSStreptococcus mutans cultured under different pH (pH4.0-7.0) concentrations and containing 5% glucose and no glucose containing BHI were collected. RNA was extracted. Subsequently, F-ATPase gene was detected using real-time polymerase chain reaction. Male Wistar rats were divided randomly into caries group and control group. The rats in the caries group were fed caries feed and 5% glucose water, whereas those of control group were fed normal feed. Total RNA was extracted from plaque samples, which were collected from rats' oral cavity every two weeks. F-ATPase gene was detected by real-time PCR. In the 11th week, the upper and lower jaw bone specimens of rats were taken, and molar caries damage assessed.

RESULTSThe expression of F-ATPase in the caries group was higher than that in the control group (P<0.05). In addition, the gene was expressed highest in pH5.0 and the lowest in pH4.0 (P<0.05). 2) The expression of F-ATPase progressively increased during the caries development in both groups; expression in the caries group was higher than that in control group (P<0.05).

CONCLUSIONAcid-resisting viru-lence factor F-ATPase is related closely with the incidence and development of dental caries.

Adenosine Triphosphatases ; metabolism ; Animals ; Dental Caries ; metabolism ; microbiology ; Dental Plaque ; microbiology ; Male ; Protons ; Random Allocation ; Rats ; Rats, Wistar ; Real-Time Polymerase Chain Reaction ; Streptococcus mutans ; drug effects ; genetics ; Virulence Factors

OBJECTIVETo investigate the effects of butyl alcohol extract of baitouweng decoction (BAEB) on the fungal cell surface hydrophobicity (CSH), filamentation and biofilm formation of Candida tropicalis.

METHODGradual dilution method was used to determine the MIC. XTT assay was applied to determine the SMIC80. Time-Kill assay was employed to draw the Time-Kill curve. The water-hydrocarbon two-phase assay was used to measure the cell surface hydrophobicity. Scanning electron microscopy (SEM) was applied to observe the morphological changes of the biofilm. Confocal laser scanning microscopy (CLSM) was applied to determine the thickness of the biofilm. The quantification real-time PCR (qRT-PCR) was used to detect expression changes of releated genes (UME6, ALST3 and NRG1). result: The MICs of BAEB against C. tropicalis strains are determined as 64-128 mg x L(-1). The SMIC80 s of BAEB against the biofilm of Candida tropicalis strains are determined as 256-512 mg x L(-1). Time-Kill curve results indicate that BAEB has a promise fungicidal effect at 256 and 512 mg x L(-1). SEM results shows that 512 mg x L(-1) BAEB can inhibit the formation of C. tropicalis biofilm on Silicone catheter, and the morphology of biofilm is also affected by BAEB. The thickness of C. tropicalis biofilm is reduced by BAEB according to CLSM results. Furthermore, qRT-PCR results indicate that expression of UME6 and ALST3 are significantly down-regulated by BAEB 256,512 mg x L(-1), and NRG1 is not affected by BAEB.

CONCLUSIONBAEB inhibits effectively the CSH, filamentation and biofilm formation of VVC strains of C. tropicalis.

Antifungal Agents ; chemistry ; pharmacology ; Biofilms ; drug effects ; Candida tropicalis ; drug effects ; genetics ; physiology ; Candidiasis ; microbiology ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; Fungal Proteins ; genetics ; metabolism ; Gene Expression Regulation, Fungal ; drug effects ; Humans ; Virulence Factors ; genetics ; metabolism

Verocytotoxic Escherichia (E.) coli strains are responsible for swine oedema disease, which is an enterotoxaemia that causes economic losses in the pig industry. The production of a vaccine for oral administration in transgenic seeds could be an efficient system to stimulate local immunity. This study was conducted to transform tobacco plants for the seed-specific expression of antigenic proteins from a porcine verocytotoxic E. coli strain. Parameters related to an immunological response and possible adverse effects on the oral administration of obtained tobacco seeds were evaluated in a mouse model. Tobacco was transformed via Agrobacteium tumefaciens with chimeric constructs containing structural parts of the major subunit FedA of the F18 adhesive fimbriae and VT2e B-subunit genes under control of a seed specific GLOB promoter. We showed that the foreign Vt2e-B and F18 genes were stably accumulated in storage tissue by the immunostaining method. In addition, Balb-C mice receiving transgenic tobacco seeds via the oral route showed a significant increase in IgA-positive plasma cell presence in tunica propria when compared to the control group with no observed adverse effects. Our findings encourage future studies focusing on swine for evaluation of the protective effects of transformed tobacco seeds against E. coli infection.
Administration, Oral ; Agrobacterium tumefaciens ; Animals ; Antigens, Bacterial/genetics/metabolism ; Bacterial Vaccines/administration & dosage/adverse effects/*pharmacology ; Edema Disease of Swine/*immunology/microbiology ; Escherichia coli Infections/immunology/microbiology/*veterinary ; Escherichia coli Proteins/*genetics/metabolism ; Female ; Fimbriae Proteins/genetics/metabolism ; Genetic Engineering ; Intestines/immunology/microbiology/pathology ; Mice ; Mice, Inbred BALB C ; Models, Animal ; Plants, Genetically Modified/*genetics/metabolism ; Seeds/genetics/metabolism ; Shiga Toxin 2/genetics/metabolism ; Shiga-Toxigenic Escherichia coli/genetics/immunology/*pathogenicity ; Swine ; Tobacco/*genetics/metabolism ; Virulence Factors/genetics/metabolism

Protein phosphorylation on tyrosine has emerged as a key device in the control of numerous cellular functions in bacteria. In this article, we review the structure and function of bacterial tyrosine kinases and phosphatases. Phosphorylation is catalyzed by autophosphorylating adenosine triphosphate-dependent enzymes (bacterial tyrosine (BY) kinases) that are characterized by the presence of Walker motifs. The reverse reaction is catalyzed by three classes of enzymes: the eukaryotic-like phosphatases (PTPs) and dual-specific phosphatases; the low molecular weight protein-tyrosine phosphatases (LMW-PTPs); and the polymerase-histidinol phosphatases (PHP). Many BY kinases and tyrosine phosphatases can utilize host cell proteins as substrates, thereby contributing to bacterial pathogenicity. Bacterial tyrosine phosphorylation/dephosphorylation is also involved in biofilm formation and community development. The Porphyromonas gingivalis tyrosine phosphatase Ltp1 is involved in a restraint pathway that regulates heterotypic community development with Streptococcus gordonii. Ltp1 is upregulated by contact with S. gordonii and Ltp1 activity controls adhesin expression and levels of the interspecies signal AI-2.
Bacteria ; enzymology ; Bacterial Proteins ; genetics ; metabolism ; Biofilms ; growth & development ; Gene Expression Regulation, Bacterial ; Host-Pathogen Interactions ; Phosphorylation ; Polysaccharides, Bacterial ; biosynthesis ; Porphyromonas gingivalis ; enzymology ; Protein Processing, Post-Translational ; Protein Structure, Tertiary ; Protein Tyrosine Phosphatases ; chemistry ; genetics ; metabolism ; Protein-Tyrosine Kinases ; chemistry ; genetics ; metabolism ; Quorum Sensing ; Signal Transduction ; Streptococcus gordonii ; enzymology ; Virulence Factors ; metabolism

As the pathogenic bacterial virulence and avirulence factors, transcription activator like (TAL) effectors of Xanthomonas can resulted in the host diseases or resistance responses. TAL effectors can specifically bind the target DNA of host plant with a novel protein-DNA binding pattern in which two amino acids recognize one nucleotide. The complexities of TAL-DNA binding have the feasibility in use of gene therapy through homologous recombination and site-specific mutation. By using the molecular recognition code between TAL-effectors and host target genes, we can exploit both the susceptible and resistance genes; broad spectrum resistance induced by multiple TAL effectors could also be manipulated. Deeper insight in the area of protein-DNA binding mechanism will benefit the application in the biomedical engineering and agricultural engineering. This article reviews the findings and functions of TAL effectors, the binding specificity and recognition code between TAL-effectors and host target genes. The possible applications and future prospects of the molecular recognition code have been discussed.
Base Sequence ; DNA, Plant ; metabolism ; Genes, Plant ; Genetic Code ; genetics ; Host-Pathogen Interactions ; Molecular Sequence Data ; Plant Diseases ; genetics ; prevention & control ; Transcriptional Activation ; Virulence Factors ; genetics ; metabolism ; Xanthomonas ; genetics ; pathogenicity

Dermonecrotic toxin (DNT) is identified as one of the most important virulence factor of Bordetella bronchiseptica. The complete coding sequence (4 356 bp) of the dnt gene was cloned into the prokaryotic expression vector pET-28a, and expressed in the Eschierichia coli BL21 (DE3) under IPTG (Isopropyl-beta-D-thiogalactopyranoside) induction. The recombinant His6-DNT protein showed immunological reactivity in the Western-blot analysis. The recombinant protein was purified from crude lysates of BL21 harboring pET-DNT with the purity of 93.2%. His6-DNT showed the dermonecrotic effects in the infant mouse assay. However, rabbit anti-serum against recombinant DNT protein could neutralize the dermonecrotic effects of native DNT to the infant mice in vivo. These findings suggest that the recombinant DNT protein retained the characteristics and immunogenicity of native DNT. Furthermore, this approach could be used to induce active immunity and serum immunoglobulin for production of a passive therapeutic reagent. In this study, we have shown that the recombinant His6-DNT protein retained the characteristics of native DNT of B. bronchiseptica, which built a good foundation for the further research on the structure and function of DNT.
Animals ; Animals, Newborn ; Bordetella bronchiseptica ; metabolism ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; genetics ; Mice ; Neutralization Tests ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; immunology ; Transglutaminases ; biosynthesis ; genetics ; Virulence Factors, Bordetella ; biosynthesis ; genetics

PURPOSE: Oral squamous carcinoma (OSCC) cells exhibit resistance to chemotherapeutic agent-mediated apoptosis in the late stage of malignancy. Increased levels of heat shock proteins 70 (HSP70) in cancer cells are known to confer resistance to apoptosis. Since recent advances in the understanding of bacterial toxins have produced new strategies for the treatment of cancers, we investigated the effect of Pseudomonas aeruginosa exotoxin A (PEA) on HSP70 expression and induction of apoptosis in chemoresistant OSCC cell line (YD-9). MATERIALS AND METHODS: The apoptotic effect of PEA on chemoresistant YD-9 cells was confirmed by MTT, Hoechst and TUNEL stains, DNA electrophoresis, and Western blot analysis. RESULTS: While YD-9 cells showed high resistance to chemotherapeutic agents such as etoposide and 5-fluorouraci (5-FU), HSP70 antisense oligonucelotides sensitized chemoresistant YD-9 cells to etoposide and 5-FU. On the other hand, PEA significantly decreased the viability of YD-9 cells by deteriorating the HSP70-relating protecting system through inhibition of HSP70 expression and inducing apoptosis in YD-9 cells. Apoptotic manifestations were evidenced by changes in nuclear morphology, generation of DNA fragmentation, and activation of caspases. While p53, p21, and E2F-1 were upregulated, cdk2 and cyclin B were downregulated by PEA treatment, suggesting that PEA caused cell cycle arrest at the G2/M checkpoint. CONCLUSION: Therefore, these results indicate that PEA reduced the chemoresistance through inhibition of HSP70 expression and also induced apoptosis in chemoresistant YD-9 cells.
ADP Ribose Transferases/*pharmacology ; Antineoplastic Agents/*pharmacology ; Apoptosis/drug effects ; Bacterial Toxins/*pharmacology ; Blotting, Western ; Carcinoma, Squamous Cell/drug therapy/*metabolism ; Cell Cycle/drug effects ; Cell Line, Tumor ; Chromatography, Liquid ; Cyclin B/metabolism ; Cyclin-Dependent Kinase 2/metabolism ; Drug Resistance, Neoplasm/*drug effects ; E2F1 Transcription Factor/metabolism ; Electrophoresis ; Exotoxins/*pharmacology ; HSP70 Heat-Shock Proteins/genetics/*metabolism ; Humans ; In Situ Nick-End Labeling ; Mouth Neoplasms/drug therapy/*metabolism ; Tandem Mass Spectrometry ; Tumor Suppressor Protein p53/metabolism ; Virulence Factors/*pharmacology