Sumio Shinoda

Publications (55)107.15 Total impact

• Article: Ecological study of pathogenic vibrios in aquatic environments.

  Sumio Shinoda, Yuki Furumai, Sei-Ichi Katayama, Tamaki Mizuno, Shin-Ichi Miyoshi
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  ABSTRACT: An ecological study of pathogenic vibrios in aquatic environments of Okayama was carried out. The number of Vibrio parahaemolyticus detected in the sea area was comparatively smaler than that found in the survey of about two decades ago. Various reasons for the decrease in the case of food poisoning by V. parahaemolyticus have been suggested but the lower number of the vibrio in aquatic environments may be one explanation. Although the number of V. vulnificus was also not as large, most of the isolates possessed the pathogenic genes, vvp and vvh, suggesting the potential for fatal pathogenicity to patients having underlying diseases. As for V. cholerae, some non-O1/non-O139 serovar isolates were detected in a fresh water area, and many of them had hlyA, the gene for hemolysin which acts as a pathogenic factor in sporadic cases of diarrhea. Thus, the total number of pathogenic vibrios detected was not of concern. However, the marine products of these areas are shipped in wide area and are for general consumption. Therefore, it is necessary to continue to survey pathogenic vibrios in aquatic environments in order to ensure food hygiene.
  Biocontrol science. 01/2013; 18(1):53-8.
• Article: Proteases produced by vibrios.

  Sumio Shinoda, Shin-Ichi Miyoshi
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  ABSTRACT: Bacteria of the genus Vibrio are normal habitants of the aquatic environment but the some species are believed to be human pathogens. Pathogenic vibrios produce various pathogenic factors, and the proteases are also recognized to play pathogenic roles in the infection: the direct roles by digesting many kinds of host proteins or indirect roles by processing other pathogenic protein factors. Especially VVP from Vibrio vulnificus is thought to be a major pathogenic factor of the vibrio. Although HA/P, the V. cholerae hemagglutinin/protease, is not a direct toxic factor of cholera vibrio, its significance is an undeniable fact. Production of HA/P is regulated together with major pathogenic factors such as CT (cholera toxin) or TCP (toxin co-regulated pilus) by a quorum-sensing system. HA/P is necessary for full expression of pathogenicity of the vibrio by supporting growth and translocation in the digestive tract. Processing of protein toxins such as CT or El Tor hemolysin is also an important pathogenic role.
  Biocontrol science 03/2011; 16(1):1-11. · 0.78 Impact Factor
• Article: Prevalence and antimicrobial resistance of Salmonella in retail foods in northern China.

  He Yan, Lin Li, M Jahangir Alam, Sumio Shinoda, Shin-Ichi Miyoshi, Lei Shi
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  ABSTRACT: A total of 387 retail meat, seafood and milk powder samples were collected from nine cities in northern China in 2005 and screened for the presence of Salmonella. Salmonella strains isolated were subjected to serotyping and antimicrobial susceptibility testing. Salmonella was isolated from 81 (20.9%, 81/387) samples and classified into 23 serotypes. The isolates were frequently resistant to sulfamethoxazole (86.4%), sulfamethoxazole/trimethoprim (48.1%), nalidixic acid (30.9%), tetracycline (19.8%), carboxybenzylpenicillin (17.3%), amoxicillin (17.3%) and ampicillin (16.0%). The multiple resistance (resistance to ≥ 3 antibiotics) was found in 29.6% (n = 24) isolates. Additionally, 4 isolates from chicken displayed the ACSSuTNx profile, resistant to ampicillin, chloramphenicol, streptomycin, sulfonamide, tetracycline and nalidixic acid, in particular, strain HBS084 showing the resistance to as many as 20 antibiotics. Salmonella from chicken showed the higher frequency of antimicrobial resistance. Our findings indicate that in northern China food products of animal origin can be a source of exposure for consumers to multiresistant Salmonella strains.
  International journal of food microbiology 10/2010; 143(3):230-4. · 3.01 Impact Factor
• Source

  Available from: pharm.or.jp

  Article: Occurrence and Characteristics of Class 1 and 2 Integrons in Clinical Bacterial Isolates from Patients in South China

  He Yan, Lin Li, Minhua Zong, Muhammad Jahangir Alam, Sumio Shinoda, Lei Shi
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  ABSTRACT: Recent studies have shown that integrons play a major role in spreading antibiotic resistance genes in clinical settings, as antibiotic resistance genes are frequently found located at gene cassettes. Polymerase chain reaction (PCR) analyses were carried out for the detection of the integrase genes of the three classes of integrons, and their gene cassettes were characterized in 118 clinical strains, including both gram-positive and gram-negative bacteria, isolated from a hospital in Guangzhou, China during 2004. Class 1 and 2 integrons were detected in 76.3% (90/118) and 0.8% (1/118) of the tested clinical isolates, respectively. Moreover four isolates were positive for both the inte-grons and no class 3 was detected. Some of them were first reported, such as Enterococcus faecalis, Enterococcus faecium, Alcaligenes sp., and Flavobacterium sp. Seven different arrays of gene cassettes of class 1 integron were found, and a high prevalence of dfrA12-orfF-aadA2 genes was observed. In addition, we identified a new none-open reading frame (ORF) cassette in a class 1 integron positive clinical coagulase-negative Staphylococcus strain GH69. The none-ORF cassette, a 700 bp sequence containing a 441 bp ORF and a 59-base element, is first charac-terized in this study. All class 2 integrons carried an array of gene cassettes dfrA1-sat2-aadA1. Moreover bacteria contain more than one integrons were also found in this study. Resistance to trimethoprim-sulfamethoxazole was frequently found to be encoded within integrons. Therefore, it is important that guidelines for the prudent use of antimicrobial agents are adopted and surveillance programs are established.
  Journal of Health Science. 01/2010; 56:442-450.
• Article: Modulation of Vibrio mimicus hemolysin through limited proteolysis by an endogenous metalloprotease.

  Tamaki Mizuno, Syed Z Sultan, Yoshimi Kaneko, Tomonaga Yoshimura, Yoko Maehara, Hiroshi Nakao, Tomofusa Tsuchiya, Sumio Shinoda, Shin-ichi Miyoshi
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  ABSTRACT: Vibrio mimicus is a causative agent of human gastroenteritis and food poisoning, and this species produces an enterotoxic hemolysin (V. mimicus hemolysin) as a virulence determinant. Vibrio mimicus hemolysin is secreted as an 80 kDa precursor, which is later converted to the 66 kDa mature toxin through removal of an N-terminal propeptide via cleavage of the Arg151-Ser152 bond. In this article, we investigate the role of the endogenous metalloprotease (V. mimicus protease) in the maturation of V. mimicus hemolysin. In vitro experiments using purified proteins showed that, although it activated the precursor at the early stage via cleavage of the Asn157-Val158 bond, V. mimicus protease finally converted the activated and physiologically maturated toxin to a 51 kDa protein through removal of the C-terminal polypeptide. This 51 kDa derivative was unable to lyse erythrocytes because of its inability to bind to the erythrocyte membrane. Vibrio mimicus protease-negative strains were found to produce high levels of V. mimicus hemolysin at the logarithmic phase of bacterial growth and maintained high hemolytic activity even at the stationary phase. These findings indicate that, although it is not directly related to toxin maturation in vivo, V. mimicus protease can modulate the activity of V. mimicus hemolysin and/or its precursor through limited proteolysis.
  FEBS Journal 03/2009; 276(3):825-34. · 3.79 Impact Factor
• Article: GROWTH PHASE-DEPENDENT PRODUCTION OF A TOXIC METALLOPROTEASE BY VIBRIO VULNIFICUS

  Shin-Ichi Miyoshi, Syed Zafar Sultan, Yumi Yasuno, Sumio Shinoda
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  ABSTRACT: Vibrio vulnificus, a ubiquitous estuarine bacterium, is divided into two groups based on the virulence potential. Group 1 is a causative agent of human fatal septicemia, which is characterized by edematous and hemorrhagic secondary skin lesions on the limbs. This human pathogen secretes a toxic metalloprotease as an important virulence determinant. The protease can evoke the skin damage through enhancement of the vascular permeability and destruction of the capillaries. Group 2 is an etiological agent of epizooticus in the cultured eels. Significant levels of metalloprotease as well as autoinducer, a well-known signal molecule of cell-density dependent regulatory system for production of virulence determinants, were found to be secreted by both the groups at early stationary phase but not middle logarithmic phase when the bacteria were cultivated at 25°C. Expression of the protease gene also was found to be increased several times at the stationary phase. Therefore, the autoinducer molecules that had accumulated might have accelerated the expression of the protease gene. In contrast, when cultivated at 37°C, far less amounts of the protease and autoinducer were produced even at the stationary phase. Most patients suffering from V. vulnificus septicemia have underlying diseases causing elevation of the serum iron level. When incubated in human serum supplemented with ferric chloride at 37°C, only Group 1 V. vulnificus showed steady bacterial multiplication and protease production but secretion of significant level of autoinducer could not be detected. Hence, the protease production by Group 1 V. vulnificus in human serum containing ferric ion is also dependent on the bacterial growth; however, protease production in this condition does not require the accumulation of the autoinducer.
  10/2008; 25(1):19-30.
• Article: An Exocellular Cytolysin Produced by Vibrio vulnificus CDC B3547, a Clinical Isolate in Biotype 2 (Serovar E)

  Shin‐ichi Miyoshi, Aya Morita, Tomoko Teranishi, Ken‐ichi Tomochika, Shigeo Yamamoto, Sumio Shinoda
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  ABSTRACT: Vibrio vulnificus biotype 2, a primary eel pathogen, is also an opportunistic pathogen for humans. The strains in this biotype secrete a cytolysin into the culture medium. The cytolysin from the strain CDC B3547 (ATCC 33817), which was originally isolated from a human leg wound, can disrupt various kinds of eukaryotic cells including erythrocytes and mast cells, and artificial vesicles, liposomes. The cytolysin is a 50 kDa single‐chain protein and is categorized into the pore‐forming toxins. After binding tightly to the cell‐membrane cholesterol in a temperature‐independent manner, the toxin molecules assemble each other in a temperature‐dependent manner, forming a small transmembrane pore. When incubated with a metalloprotease from the same species, the cytolysin is converted to the nicked toxin composed of some peptide chains, joined with disulfide bond(s). This nicked toxin is more hydrophilic while maintaining comparable cytolytic activity.
  10/2008; 23(1):111-121.
• Article: Bacterial Proteases as Pathogenic Factors, with Special Emphasis on Vibrio Proteases

  Sumio Shinoda, Shin-Ichi Miyoshi, Hitoshi Wakae, Monzur Rahman, Ken-Ichi Tomochika
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  ABSTRACT: Abstract Bacterial proteases play various pathogenic roles in infection. Pathogenic species of the genus Vibrio, such as V. cholerae, V. parahaemolyticus or V. vulnificus also produce exocellular proteases, and almost of them are metalloproteases having a zinc atom. V. vulnificus is an opportunistic human pathogen causing septicemia or wound infections characterized by the formation of edema, necrotic ulcer and cellulitis on the skin. The protease produced by the vibrio (VVP) enhanced vascular permeability through activation of the Hageman factor-plasma kallikrein-kinin cascade and/or exocytotic histamine release from mast cells, and formed hemorrhagic lesions which subsequently provoke severe dermonecrosis. Thus, VVP is the most probable candidate for edema formation in the infection. Other pathogenic roles of VVP were also demonstrated. The VVP gene was cloned, and the amino acid sequence was deduced from the nucleotide sequence. The mature protein was demonstrated to be composed of 413 amino acid residues and showed 69 to 74% homology with other vibrio proteases.
  09/2008; 15(4):327-339.
• Article: Bacterial Metalloprotease as the Toxic Factor in Infection

  Shin-Ichi Miyoshi, Sumio Shinoda
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  ABSTRACT: Abstract Metalloproteases, in which zinc metal ion is essential for catalytic activity, are produced by various human pathogenic bacteria. These metalloproteases have the consensus sequence HEXXH, in which two histidine residues function as the first and second zinc ligands. However, on the basis of the location of the third zinc ligand, they are classified into three families: the thermolysin, serralysin and neurotoxin families. Members of the thermolysin family are synthesized as an inactive precursor with a N-terminal propeptide, and maturation of the precursor is achieved by several processing stages. The metalloprotease in the serralysin family is generated without a conventional propeptide, and its transport is supported by additional secreted proteins. A wide variety of pathological actions of bacterial metalloproteases have been documented. In local bacterial infections, such as keratitis, dermatitis and pneumonia, the metalloprotease functions as a decisive virulence determinant. The protease generated at the site of the infection causes necrotic or hemorrhagic tissue damage through digestion of structural components of the ground substance. The protease also enhances vascular permeability and forms edematous lesions through generation of the inflammatory mediators, histamine and bradykinin. Additionally, permeability enhancement and/or tissue damage allows bacterial dissemination into the systemic circulation. In systemic infections such as septicemia, the metalloprotease acts as a synergistic virulence factor. The disordered proteolysis of many plasma proteins by the bacterial protease causes imbalance of endogenous proteinase-proteinase inhibitor systems, disturbs physiological homeostasis, and eventually elicits an immunocompromised state in the host. The disintegration of iron-carrier proteins triggers the uptake of iron, an essential element for the bacterium. The metalloproteases produced by enteropathogens can activate enterotoxins, including cholera toxin, through limited proteolysis. Clostridial neurotoxins were recently demonstrated to be zinc-containing proteins possessing proteolytic activity. These neurotoxins specifically cleave a synaptic vesicle membrane protein or the presynaptic plasma membrane protein. Bacteroides fragilis enterotoxin is also a zinc metalloprotease.
  09/2008; 16(4):177-194.
• Article: Differential gene expression and extracellular secretion of the collagenolytic enzymes by the pathogen Vibrio parahaemolyticus.

  Shin-ichi Miyoshi, Yuko Nitanda, Kaori Fujii, Kiyomi Kawahara, Tao Li, Yoko Maehara, Thandavarayan Ramamurthy, Yoshifumi Takeda, Sumio Shinoda
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  ABSTRACT: Vibrio parahaemolyticus, a causative agent of wound infections as well as food poisoning, harbors two collagenase genes: vppC and prtV. When cultivated at 26 degrees C in gelatin broth supplemented with 3.0% NaCl, significant collagenolytic activity was detected in the culture supernatant at the early stationary phase. Native polyacrylamide gel electrophoresis analysis revealed a 90-kDa protein, and N-terminal amino acid sequencing showed that this protein was VppC, generated through truncation of 72 N-terminal amino acid residues. Additionally, significant expression of only vppC was observed by reverse transcriptase PCR. By contrast, a vppC-negative mutant constructed through single crossover homologous recombination secreted a 50-kDa-collagenolytic enzyme; however, this enzyme was a serine protease that was reported previously. These results suggest that VppC is a primary extracellular collagenase produced by V. parahaemolyticus.
  FEMS Microbiology Letters 07/2008; 283(2):176-81. · 2.04 Impact Factor
• Article: Molecular epidemiological studies of Vibrio cholerae in Bengal region.

  Sumio Shinoda, Tomoko Nakagawa, Nobuyuki Hirakawa, Shin-Ichi Miyoshi, Eiji Arakawa, Thandavarayan Ramamurthy, B Dutta, Shah M Faruque, Gopinath Balakrish Nair
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  ABSTRACT: Vibrio cholerae isolates from environmental and clinical origins in the Bengal region in which epidemics of cholera break out periodically were analyzed with particular emphasis on the molecular epidemiological features. The presence of the virulence genes (ctxA, tcpA and toxR) in the isolates was analyzed by the PCR (polymerase chain reaction) method. PFGE (pulsed-field gel electrophoresis) was performed to determine the clonal relationships between the clinical and environmental strains. Antibiograms and O serovars of the isolates were also examined. O1 and O139 strains from both clinical and environmental sources were all positive for the three virulence genes while non-O1/non-O139 strains from both sources were all negative for ctxA and tcpA but positive for toxR. PFGE patterns of recent isolates of O1 and O139 were similar in each serovar regardless of origin, suggesting a clonal relationship between the clinical and environmental strains, although comparison with past isolates or isolates from different geographical area showed some differences.
  Biocontrol science 04/2008; 13(1):1-8. · 0.78 Impact Factor
• Article: The crucial amino acid residue related to inactivation of Vibrio vulnificus hemolysin.

  Mitsutoshi Senoh, Yuka Okita, Sumio Shinoda, Shin-ichi Miyoshi
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  ABSTRACT: Vibrio vulnificus, an opportunistic human pathogen causing fetal septicemia, produces a 50-kDa pore-forming toxin as a virulence factor. This toxin consists of 451 amino acid residues; however, there are two types of this toxin on the basis of the difference of some amino acid residues, type 1 (Leu(281), Ser(415), Asn(435)/Asp(435), Asn(438)) and type 2 (Ile(281), Asn(415), Asn(435), Thr(438)). In the present study, two characteristic properties of type 2 toxin that was elaborated by V. vulnificus cells or synthesized by the in vitro system were compared to those of type 1 toxin. Type 2 toxin was found to be more resistant to spontaneous inactivation at 37 degrees C and to specific inactivation by cholesterol. On the other hand, a variant of type 2 toxin (Asp(435), Asn(438)) showed the same properties as type 1 toxin. The replacement of the 438th Asn to Thr (N438T), but not the 435th Asp to Asn (D435N), resulted in reversion of the variant type 2 toxin to typical type 2 toxin. These findings indicate that a single amino acid residue, Thr(438), may be critical for higher stability of type 2 toxin.
  Microbial Pathogenesis 02/2008; 44(1):78-83. · 1.94 Impact Factor
• Article: Haemolysin produced by Vibrio mimicus activates two Cl- secretory pathways in cultured intestinal-like Caco-2 cells.

  Akira Takahashi, Shin-ichi Miyoshi, Noriko Takata, Masayuki Nakano, Akiko Hamamoto, Kazuaki Mawatari, Nagakatsu Harada, Sumio Shinoda, Yutaka Nakaya
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  ABSTRACT: Haemolysin (VMH) is a virulent factor produced by Vibrio mimicus, a human pathogen that causes diarrhoea. As intestinal epithelial cells are the primary targets of haemolysin, we investigated its effects on ion transport in human colonic epithelial Caco-2 cells. VMH increased the cellular short circuit current (Isc), used to estimated ion fluxes, and 125I efflux of the cells. The VMH-induced increases in Isc and 125I efflux were suppressed by depleting Ca2+ from the medium or by pretreating the cells with BAPTA-AM or by Rp-adenosin 3',5'-cyclic monophosphorothioate triethylammonium salt (Rp-cAMPS). The Cl- channel inhibitors 4,4'-disothiocyanatostibene-2,2'-disulfonic acid (DIDS), glybenclamide, and 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) suppressed the VMH-induced increases in Isc and 125I efflux. Moreover, VMH increased the intracellular concentrations of Ca2+ and cAMP. Thus, VMH stimulates Caco-2 cells to secrete Cl- by activating both Ca2+ -dependent and cAMP-dependent Cl- secretion mechanisms. VMH forms ion-permeable pores in the lipid bilayer that are non-selectively permeable to small ions. However, the ion permeability of these pores was not inhibited by glybenclamide and DIDS, and VMH did not change the cell membrane potential. These observations indicate that the pores formed on the cell membrane by VMH are unlikely to be involved in VMH-induced Cl- secretion. Notably, VMH stimulated fluid accumulation in the iliac loop test that was fully suppressed by a combination of DIDS and glybenclamide. Thus, Ca2+-dependent and cAMP-dependent Cl- secretion may be important therapeutic targets with regard to the diarrhoea that is induced by Vibrio mimicus.
  Cellular Microbiology 04/2007; 9(3):583-95. · 5.46 Impact Factor
• Article: [Proteases of genus Vibrio as the pathogenic factor].

  Sumio Shinoda, Shin-ichi Miyoshi
  Nippon Saikingaku Zasshi 06/2006; 61(2):261-71.
• Article: Biodegradation of dichloromethane by the polyvinyl alcohol-immobilized methylotrophic bacterium Ralstonia metallidurans PD11.

  Chizuko Miyake-Nakayama, Hisayoshi Ikatsu, Minoru Kashihara, Masako Tanaka, Michiko Arita, Shin-Ichi Miyoshi, Sumio Shinoda
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  ABSTRACT: A dichloromethane (DCM)-degrading bacterium, Ralstonia metallidurans PD11 NBRC 101272, was immobilized in a polyvinyl alcohol (PVA) gel to use in a bioreactor for DCM treatment. After 4-month incubation of PVA gel beads with R. metallidurans PD11 and DCM in a mineral salt medium, the cells were tightly packed in the mesh of the gel. Forty beads of the gel in 10 ml of a batch system model showed effective activity degrading 500 and 1,000 mg l(-1) DCM within 2 and 3 h, respectively. Although reduction of pH due to accumulation of chloride ion liberated from DCM decreased the activity, it was recovered by adjustment to neutral pH. The activity of the immobilized cells was not affected by addition of nutrients which were preferentially utilized by R. metallidurans PD11, unlike the activity of the free-living cells. A continuous flow system with a column was more effective for rapid degradation of DCM. Thus, the PVA gel-immobilized cell of R. metallidurans PD11 is thought to be a prospective candidate to develop the bioreactor.
  Applied Microbiology and Biotechnology 06/2006; 70(5):625-30. · 3.42 Impact Factor
• Source

  Available from: Arjun Saha

  Article: PCR-based identification of Vibrio cholerae and the closely related species Vibrio mimicus using the large chromosomal ori sequence of Vibrio cholerae.

  Arjun Saha, Reema Deb, Sangita Shah, Thandavarayan Ramamurthy, Sumio Shinoda, Asish K Mukhophadyay, Rupak K Bhadra
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  ABSTRACT: The bacterial chromosomal replication origin (ori) sequences are a highly conserved essential genetic element. In this study, the large chromosomal replication origin sequence of Vibrio cholerae (oriCIVC) has been targeted for identification of the organism, including the biotypes of serogroup O1. The oriCIVC sequence-based PCR assay specifically amplified an 890 bp fragment from all the V. cholerae strains examined. A point mutation in the oriCIVC sequence of the classical biotype of O1 serogroup led to the loss of a BglII site, which was utilized for differentiation from El Tor vibrios. Interestingly, the PCR assay amplified a similarly sized ori segment, designated as oriCIVM, from V. mimicus strains, but failed to produce any amplicon with other strains. Cloning and sequencing of the oriCIVM revealed high sequence similarity (96%) with oriCIVC. The results indicate that V. mimicus is indeed very closely related to V. cholerae. In addition, the BglII restriction fragment length polymorphism (RFLP) between oriCIVM and oriCIVC sequences allowed us to differentiate the two species. The ori sequence-based PCR-RFLP assay developed in this study appears to be a useful method for rapid identification and differentiation of V. cholerae and V. mimicus strains, as well as for the delineation of classical and El Tor biotypes of V. cholerae O1.
  FEMS Microbiology Letters 05/2006; 257(1):84-91. · 2.04 Impact Factor
• Source

  Available from: Nur A Hasan

  Article: Phenotypic and molecular characteristics of Escherichia coli isolated from aquatic environment of Bangladesh.

  Munirul Alam, Nur-A-Hasan, Sunjukta Ahsan, Gururaja Perumal Pazhani, Kazumichi Tamura, Thadavarayan Ramamurthy, Donald James Gomes, Sabita R Rahman, Atiqul Islam, Fahmina Akhtar, Sumio Shinoda, Haruo Watanabe, Shah M Faruque, Gopinath Balakrish Nair
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  ABSTRACT: Pathogenic Escherichia coli remains important etiological agent of infantile diarrhea in Bangladesh. Previous studies have focused mostly on clinical strains, but very little is known about their presence in aquatic environments. The present study was designed to characterize potentially pathogenic E. coli isolated between November 2001 and December 2003 from aquatic environments of 13 districts of Bangladesh. Serotyping of 96 randomly selected strains revealed O161 to be the predominant serotype (19%), followed by O55 and O44 (12% each), and 11% untypable. Serotype-based pathotyping of the E. coli strains revealed 47%, 30%, and 6% to belong to EPEC, ETEC, and EHEC pathotypes, respectively. The majority of the 160 strains tested were resistant to commonly used antimicrobial agents. Plasmid pro-filing showed a total of 17 different bands ranging from 1.3 to 40 kb. However, 35% of the strains did not contain any detectable plasmid, implying no correlation between plasmid and drug resistance. Although virulence gene profiling revealed 97 (61%) of the strains to harbor the gene encoding heat-stable enterotoxin (ST), 2 for the gene encoding Shiga toxin (Stx), and none for the gene for heat-labile enterotoxin (LT), serotype-based pathotyping of E. coli was not fully supported by this gene profiling. A dendrogram derived from the PFGE patterns of 22 strains of three predominant serogroups indicated two major clusters, one containing mainly serogroup O55 and the other O8. Three strains of identical PFGE profiles belonging to serogroup O55 were isolated from three distinct areas, which may be of epidemiological significance. Finally, it may be concluded that serotype-based pathotyping may be useful for E. coli strains of clinical origin; however, it is not precise enough for reliably identifying environmental strains as diarrheagenic.
  Microbiology and Immunology 02/2006; 50(5):359-70. · 1.30 Impact Factor
• Article: Proteolytic activation of Vibrio mimicus (Vm) major outer membrane protein haemagglutinin (HA) with Vm-HA/protease: Implication for understanding bacterial adherence.

  Munirul Alam, Shin-ichi Miyoshi, Kabir Uddin Ahmed, Nur A Hasan, Ken-ichi Tomochika, Sumio Shinoda
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  ABSTRACT: Vibrio mimicus (Vm) haemagglutinins (HAs), such as an extracellular HA/protease (Vm-HA/protease) and a major outer membrane protein-HA (Vm-OMPHA), have been recognized as the putative adherence factors for the bacterium. However, the mechanism by which HAs coordinate the adherence function of the bacterium remains as yet unknown. We report herein the positive interaction between Vm-HA/protease and Vm-OMPHA resulting in significant enhancement of the haemagglutinating ability. In this interaction, no cleaved polypeptide was detected; however, limited proteolysis of Vm-OMPHA was confirmed by SDS-PAGE. The proteolytic activation of the native cell-associated Vm-OMPHA by limited proteolysis was also demonstrated in several V. mimicus strains. Proteolytic activation of OMPHA was also achieved with various proteases from bacterial and eukaryotic sources. These findings may indicate a novel coordination of V. mimicus HAs in the adherence of the bacterium.
  Microbiology and Immunology 02/2006; 50(11):845-50. · 1.30 Impact Factor
• Article: Presence of LuxS/AI-2 based quorum-sensing system in Vibrio mimicus : luxO controls protease activity.

  Zafar Sultan, Shin-ichi Miyoshi, Sumio Shinoda
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  ABSTRACT: Presence of the quorum-sensing regulation system in Vibrio mimicus was investigated. The culture supernatants of V. mimicus strains were found to possess AI-2 autoinducer like activity, and the strains were found to harbor the genes which are homologous to luxS, luxO, and luxR of V. harveyi. These genes of V. harveyi have been shown to be important components of V. harveyi-like quorum-sensing system. The luxO gene homologue known to encode LuxO, the central component of the regulation system, was disrupted, and effects on protease and hemolysin activity were studied. Disruption of luxO gene resulted in the increased protease activity, but the hemolysin activity did not vary considerably.
  Microbiology and Immunology 02/2006; 50(5):407-17. · 1.30 Impact Factor
• Article: [Pathogenic factors of vibrios with special emphasis on Vibrio vulnificus].

  Sumio Shinoda
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  ABSTRACT: Bacteria of the genus Vibrio are normal habitants of the aquatic environment and play roles for biocontrole of aquatic ecosystem, but some species are believed to be human pathogens. These species can be classified into two groups according to the types of diseases they cause: the gastrointestinal infections and the extraintestinal infections. The pathogenic species produce various pathogenic factors including enterotoxin, hemolysin, cytotoxin, protease, siderophore, adhesive factor, and hemagglutinin. We studied various pathogenic factors of vibrios with special emphasis on protease and hemolysin of V. vulnificus. V. vulnificus is now recognized as being among the most rapidly fatal of human pathogens, although the infection is appeared in patients having underlying disease(s) such as liver dysfunction, alcoholic cirrhosis or haemochromatosis. V. vulnificus protease (VVP) is thought to be a major toxic factor causing skin damage in the patients having septicemia. VVP is a metalloprotease and degrades a number of biologically important proteins including elastin, fibrinogen, and plasma proteinase inhibitors of complement components. VVP causes skin damages through activation of the Factor XII-plasma kallikrein-kinin cascade and/or exocytotic histamine release from mast cells, and a haemorrhagic lesion through digestion of the vascular basement membrane. Thus, the protease is the most probable candidate for tissue damage and bacterial invasion during an infection. Pathogenic roles and functional mechanism of other factors including hemolysins of V. vulnificus and V. mimicus are also shown in this review article.
  Yakugaku zasshi journal of the Pharmaceutical Society of Japan 08/2005; 125(7):531-47. · 0.39 Impact Factor