The HNH endonuclease domain of the giant virus MutS7 specifically binds to branched DNA structures with single-stranded regions.

Most giant viruses including Mimiviridae family build large viral factories within the host cytoplasms. These giant viruses are presumed to possess specific genes that enable the rapid and massive replication of their large double-stranded DNA genomes within viral factories. It has been revealed that a functionally uncharacterized protein, MutS7, is expressed during the operational phase of the viral factory.

Multi-drug resistance pattern and genome-wide SNP detection in levofloxacin-resistant uropathogenic Escherichia coli strains.

Objectives: Antibiotic treatment is extremely stressful for bacteria and has profound effects on their viability. Such administration induces physiological changes in bacterial cells, with considerable impact on their genome structure that induces mutations throughout the entire genome. This study investigated drug resistance profiles and structural changes in the entire genome of uropathogenic Escherichia coli (UPEC) strains isolated from six adapted clones that had evolved under laboratory conditions.

Rapid Serotyping of Isolates Based on Single Nucleotide Polymorphism-Like Sequence Profiles of a Specific Gene.

Although serotyping is the most important method of identification of taxonomy in , conventional serotype determination with a complete set of antisera is time consuming and laborious. Recently, rapid serotyping procedures with polymerase chain reaction (PCR) have been developed. In this study, we established a novel PCR-based rapid serotyping method that employs a unique target gene.

Genomic Sequences of Uropathogenic Escherichia coli Strains with Various Fluoroquinolone Resistance Profiles.

The emergence of drug-resistant uropathogenic (UPEC) has hampered antibiotic therapy for urinary tract infections. To elucidate the resistance mechanisms of UPEC, we performed whole-genome sequencing of eight UPEC strains with different fluoroquinolone resistance levels. Here, we report our sequencing data, providing a valuable resource for understanding such mechanisms.

Detection of Cholera Toxin by an Immunochromatographic Test Strip.

As cholera toxin (CT) is responsible for most of the symptoms induced by Vibrio cholerae O1 or O139 infection, detection of CT is an important biomarker for diagnosis of the disease. The procedure for pathogenicity analysis of V. cholerae isolates must be carefully developed for the reason that the amount of CT produced by V.

Helicobacter pylori VacA, acting through receptor protein tyrosine phosphatase α, is crucial for CagA phosphorylation in human duodenum carcinoma cell line AZ-521.

Helicobacter pylori, a major cause of gastroduodenal diseases, produces vacuolating cytotoxin (VacA) and cytotoxin-associated gene A (CagA), which seem to be involved in virulence. VacA exhibits pleiotropic actions in gastroduodenal disorders via its specific receptors. Recently, we found that VacA induced the phosphorylation of cellular Src kinase (Src) at Tyr418 in AZ-521 cells.

In vitro safety assessments and antimicrobial activities of Lactobacillus rhamnosus strains isolated from a fermented mare's milk.

Safety and probiotic characteristics such as antimicrobial activities of three Lactobacillus rhamnosus strains, FSMM15, FSMM22 and FSMM26, previously isolated as potential probiotics from fermented mare's milk were investigated. The three FSMM strains were susceptible to ampicillin, gentamycin, kanamycin, streptomycin, tetracycline and chloramphenicol, whereas they were resistant to erythromycin (minimal inhibitory concentration (MIC) = 4-8 µg/mL) and clindamycin (MIC = 4 µg/mL); bioconversion of bile salts, hemolytic activity and mucin degradation activity were negative; enzymatic activities of α-chymotrypsin and β-glucosidase were detected, but those of α-galactosidase, β-glucuronidase and N-acetyl-β-glucosaminidase, were undetectable. Among the strains, strain FSMM15 was chosen as a safer probiotic candidate due mainly to the lack of plasminogen binding ability.

Quantitative Detection of Shiga Toxins Directly from Stool Specimens of Patients Associated with an Outbreak of Enterohemorrhagic Escherichia coli in Japan--Quantitative Shiga toxin detection from stool during EHEC outbreak.

Detection of Shiga toxins (Stx) is important for accurate diagnosis of Enterohemorrhagic Escherichia coli infection. In this study, we quantitatively analyzed Stx protein in nine patients' stool during an outbreak that occurred in Japan. Highly sensitive immunoassay (bead enzyme-linked immunosorbent assay (bead-ELISA)) revealed that the concentrations of toxins in stool of patients ranged from 0.

Ex vivo proteomics of Campylobacter jejuni 81-176 reveal that FabG affects fatty acid composition to alter bacterial growth fitness in the chicken gut.

Campylobacter jejuni is one of the leading causes of foodborne gastrointestinal illness worldwide. Here we performed ex vivo proteomic analysis of C. jejuni 81-176 in chicken, a main reservoir for human infection.

Expression of marA is remarkably increased from the early stage of development of fluoroquinolone-resistance in uropathogenic Escherichia coli.

Background: Analyses of efflux pumps overexpression and mutations in quinolone resistance determining region (QRDR) in early stage of development of resistance to fluoroquinolones (FQs) are valuable to discuss countermeasures against them. We induced levofloxacin (LVFX)-resistant strains from susceptible uropathogenic Escherichia coli in vitro to analyze the mechanisms of development of FQs-resistance.

Methods: 89 strains were exposed to discontinuous elevation of LVFX dose, and mRNA level of efflux pumps and their regulators as well as mutations developed in QRDR of LVFX-resistant strains were analyzed.

Study of the Stn protein in Salmonella; a regulator of membrane composition and integrity.

Our studies were undertaken to develop new insights into the function of the Salmonella Stn protein. An analysis of total cell membrane protein fraction suggested the possibility that Stn associates with OmpA. This possibility was confirmed by immunogold labeling using anti-OmpA antibody and far-western blotting.

Effects of oral administration of heat-killed Enterococcus faecium strain NHRD IHARA in post-weaning piglets.

Probiotic bacteria such as lactic acid bacteria (LAB) have recently received attention as candidates for alternative anti-microbial feed additives. We previously isolated Enterococcus faecium strain NHRD IHARA (FERM BP-11090, NHRD IHARA strain) and reported its probiotic efficacy. However, we have not determined the effect of oral administration of heat-killed cells of this strain.

A new protocol to detect multiple foodborne pathogens with PCR dipstick DNA chromatography after a six-hour enrichment culture in a broad-range food pathogen enrichment broth.

A quick foodborne pathogen screening method after six-hour enrichment culture with a broad-range food pathogen enrichment broth is described. Pathogenic factors of Salmonella enterica, Shigella spp., enteroinvasive Escherichia coli, and enterohemorrhagic E.

Development of an immunochromatographic test strip for detection of cholera toxin.

Because cholera toxin (CT) is responsible for most of the symptoms induced by Vibrio cholerae infection, detection of CT is critical for diagnosis of the disease. In this study, we constructed an immunochromatographic test strip for detection of CT (CT-IC) with polyclonal antibodies developed against purified recombinant whole CT protein. The detection limit of the CT-IC was 10 ng/mL of purified recombinant CT, and it could detect the CT in culture supernatant of all 15 toxigenic V.

Staphylococcus aureus clinical isolates: antibiotic susceptibility, molecular characteristics, and ability to form biofilm.

Periodic monitoring of Staphylococcus aureus characteristics in a locality is imperative as their drug-resistant variants cause treatment problem. In this study, antibiograms, prevalence of toxin genes (sea-see, seg-ser, seu, tsst-1, eta, etb, and etd), PFGE types, accessory gene regulator (agr) groups, and ability to form biofilm of 92 S. aureus Thailand clinical isolates were investigated.

Uropathogenic specific protein gene, highly distributed in extraintestinal uropathogenic Escherichia coli, encodes a new member of H-N-H nuclease superfamily.

Background: The uropathogenic specific protein (Usp) and three OrfU proteins (OrfU1, OrfU2 and OrfU3) are encoded in the putative small pathogenicity island which is closely associated with Uropathogenic Escherichia coli. Although homology search revealed that Usp and OrfUs have a homology with nuclease-type bacteriocins, which possess H-N-H nuclease motif, and immunity proteins respectively, the molecular activity of these proteins was never investigated. In this study, we try to over-express Usp in E.

Salmonella enterotoxin (Stn) regulates membrane composition and integrity.

The mechanism of action of Salmonella enterotoxin (Stn) as a virulence factor in disease is controversial. Studies of Stn have indicated both positive and negative effects on Salmonella virulence. In this study, we attempted to evaluate Stn function and its effects on Salmonella virulence.

Toxic marine puffer fish in Thailand seas and tetrodotoxin they contained.

A total of 155 puffers caught from two of Thailand's seas, the Gulf of Siam and the Andaman seas, during April to July 2010 were included in this study. Among 125 puffers from the Gulf of Siam, 18 were Lagocephalus lunaris and 107 were L. spadiceus which were the same two species found previously in 2000-2001.

Pathogenesis of experimental amyloid protein A amyloidosis in sore hocks-affected rabbits.

Although the experimental transmission of amyloid protein A (AA) amyloidosis with amyloid-enhancing factor has been studied intensively, its pathogenesis remains obscure. We previously found that rabbits affected with 'sore hocks' (SH) uniquely developed AA amyloidosis in response to primary inflammatory stimulation followed by the administration of bovine AA fibrils. However, it is unknown why only the rabbits with preexisting SH developed experimental AA amyloidosis.

Hybrid & El Tor variant biotypes of Vibrio cholerae O1 in Thailand.

Background & Objectives: El Tor Vibrio cholerae O1 carrying ctxB C trait, so-called El Tor variant that causes more severe symptoms than the prototype El Tor strain, first detected in Bangladesh was later shown to have emerged in India in 1992. Subsequently, similar V. cholerae strains were isolated in other countries in Asia and Africa.

Helicobacter pylori VacA reduces the cellular expression of STAT3 and pro-survival Bcl-2 family proteins, Bcl-2 and Bcl-XL, leading to apoptosis in gastric epithelial cells.

Background: Helicobacter pylori vacuolating cytotoxin, VacA, stimulates apoptosis via a mitochondria-dependent pathway. VacA induces apoptosis via activation of the pro-apoptotic B-cell lymphoma (Bcl)-2 family proteins, Bcl-2-associated X protein (Bax) and Bcl-2 homologous antagonist/killer (Bak), while the implication of such pro-survival Bcl-2 family members as Bcl-2 and Bcl-XL in the VacA-induced apoptosis remains unknown. Signal transduction and activator of transcription 3 (STAT3) is a pivotal transcription factor that upregulates Bcl-2 and Bcl-XL.

Helicobacter pylori CagA inhibits endocytosis of cytotoxin VacA in host cells.

Helicobacter pylori, a common pathogen that causes chronic gastritis and cancer, has evolved to establish persistent infections in the human stomach. Epidemiological evidence suggests that H. pylori with both highly active vacuolating cytotoxin A (VacA) and cytotoxin-associated gene A (CagA), the major virulence factors, has an advantage in adapting to the host environment.

A V H H that neutralizes the zinc metalloproteinase activity of botulinum neurotoxin type A.

The current treatment of botulism is to administer animal-derived antitoxin, which frequently causes severe adverse reactions in the recipients. In this study, a heavy chain antibody fragment (VH/V(H)H) phage display library was constructed by amplification of the immunoglobulin genes of a nonimmune camel, Camelus dromedarius, using primers specific to human VH gene segments. A recombinant light chain of type A botulinum toxin, BoTxA/LC, with zinc endoprotease activity was used in phage bio-panning to select phage clones displaying BoTxA/LC-bound VH/V(H)H.

Human monoclonal ScFv neutralize lethal Thai cobra, Naja kaouthia, neurotoxin.

Animal derived anti-Naja. kaouthia (Thai cobra) venom is used for specific treatment of the snake bitten victims. Many recipients develop allergic reaction or anti-isotype response which causes serum sickness.