Response of enteric luminous bacteria to environmental conditions in the gut of the fish

Alluri, Ramesh; Venugopalan, V. K.

doi:10.1111/j.1365-2672.1989.tb04574.x

Cited by 19 publications

(9 citation statements)

References 14 publications

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“…Vibrio harveyi is a Gram-negative, luminous, marine bacterium occurring either free living or in association with marine forms of life such as fish and crustaceans (O'Brien & Sizemore, 1979;Orndorff & Colwell, 1980;Ramesh & Venugopalan, 1989). The organism has been reported as a major causal agent of luminous vibriosis, which affects a diverse range of marine invertebrates.…”

Section: Introductionmentioning

confidence: 99%

Characterization and virulence retention of viable but nonculturable Vibrio harveyi

Sun

Chen

Zhong

et al. 2008

FEMS Microbiology Ecology

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Vibrio harveyi has been reported to enter into a viable but nonculturable (VBNC) state. Two clinical V. harveyi strains, SF1 and CW2, and the type strain, VIB295(T), were incubated in sterilized seawater at 4 degrees C. Plate counts in these strains declined to undetectable levels (<0.1 CFU mL(-1)) within 69, 67 and 65 days, respectively. The direct viable count (DVC) declined from 10(6) to 10(4) active cells mL(-1) and remained constant at this level by a DVC. VBNC cell numbers could be restored via a temperature upshift when grown in yeast extract with the addition of Tween 20 or compound vitamin B. Reverse transcriptase-PCR was used to monitor virulence gene expression within VBNC cells. No expression of the hemolysin gene was detected in VBNC cells. VBNC and resuscitative cells were intraperitoneally injected into zebra fish separately. No death was observed in the groups inoculated with VBNC cells. The fish inoculated with the resuscitative cells died within 7 days, the lethal dose 50% (LD(50)) being 2.85 x 10(4) CFU mL(-1), a value similar to that for groups inoculated with normal cells (2.28 x 10(4) CFU mL(-1)). This suggested that VBNC V. harveyi might retain pathogenic potential.

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Section: Introductionmentioning

confidence: 99%

Characterization and virulence retention of viable but nonculturable Vibrio harveyi

Sun

Chen

Zhong

et al. 2008

FEMS Microbiology Ecology

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“…1971 ; O’Brien & Sizemore 1979; Ruby & Morin 1979; Ramesh et al . 1986 ; Ramesh & Venugopalan 1989). The pathogenicity of this Vibrio species has been recognized in cultured penaeids worldwide ( Sunaryanto & Mariam 1986; Lavilla‐Pitogo et al .…”

Section: Introductionmentioning

confidence: 99%

Cysteine protease is a major exotoxin of pathogenic luminousVibrio harveyiin the tiger prawn,Penaeusmonodon

Liu

Lee

1999

Letters in Applied Microbiology

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. 1999. The role of an extracellular cysteine protease, produced by pathogenic luminous Vibrio harveyi strain 820514 originally isolated from diseased tiger prawn (Penaeus monodon), in the disease process in the prawns was studied. The protease was lethal to P. monodon with an LD 50 value of 0·3 mg protein g −1 prawn. The lethal toxicity of the extracellular products (ECP) of the bacterium was neutralized by pre-incubation of the ECP with rabbit antiserum to the cysteine protease. Pre-incubation of ECP with CuCl 2 (an inhibitor of cysteine protease) also inhibited toxicity. This suggests that cysteine protease is the major toxin produced by the bacterium. The present protease is the first toxic cysteine protease to be found in Vibrio species.

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“…Surprisingly, the level of vhh-specific RNA transcript produced by VIB 645 was found to be very low. We conclude that the hemolytic phenotype of VIB 645 is not due to increased expression of one or both copies of the vhh gene.Vibrio harveyi is a gram-negative, luminous bacterium which is widely distributed in the marine environment (28,29). Recently, this organism has emerged as a serious pathogen of marine animals.…”

mentioning

confidence: 99%

“…Vibrio harveyi is a gram-negative, luminous bacterium which is widely distributed in the marine environment (28,29). Recently, this organism has emerged as a serious pathogen of marine animals.…”

mentioning

confidence: 99%

Duplication of Hemolysin Genes in a Virulent Isolate of Vibrio harveyi

Zhang¹,

Meaden²,

Austin³

2001

Appl Environ Microbiol

103

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Vibrio harveyi VIB 645, which is very pathogenic towards salmonids and produces extracellular product with a high titer of hemolytic activity towards fish erythrocytes, was found to contain two closely related hemolysin genes (designated vhhA and vhhB), whereas the majority of strains examined (11 of 13) carried only a single hemolysin gene. Both genes from VIB 645 were cloned and sequenced. The open reading frames (ORFs) of vhhA and vhhB shared a high level of identity (98.8%) and were predicted to encode identical polypeptides comprising 418 amino acid residues. The VHH protein shows homology to the lecithinase of V. mimicus and V. cholerae. Transformants of Escherichia coli containing the ORF of either vhhA or vhhB displayed weak hemolytic activity in rainbow trout blood agar. The hemolytic activity was very high when the ORF of vhhB was cloned in E. coli together with the native promoter. Surprisingly, the level of vhh-specific RNA transcript produced by VIB 645 was found to be very low. We conclude that the hemolytic phenotype of VIB 645 is not due to increased expression of one or both copies of the vhh gene.Vibrio harveyi is a gram-negative, luminous bacterium which is widely distributed in the marine environment (28,29). Recently, this organism has emerged as a serious pathogen of marine animals. For example, the organism has been reported as a primary pathogen of cultured penaeid shrimp, especially in South America and Asia (1,10,18,26,33,36). Additionally, V. harveyi has been associated with diseases in finfish (1,8,9,15,30) and pearl oysters (24). However, little is known about the pathogenicity mechanisms of V. harveyi. Liu et al. (19) considered that proteases, phospholipases, or hemolysins might be important for pathogenicity; cysteine protease has been reported as the major exotoxin to penaeid shrimp (16,17,20). Montero and Austin (21) suggested that the lipopolysaccharide might constitute the lethal toxin of V. harveyi E2 to penaeid shrimp. We have previously examined a large number of well-characterized V. harveyi cultures and found that the hemolysin activity in the extracellular product was involved in pathogenesis in salmonids. V. harveyi VIB 645, which was the most pathogenic isolate, produced extracellular product with the highest titer of hemolytic activity towards Atlantic salmon (1:256) and rainbow trout erythrocytes (1:32) (40).In general, bacterial hemolysins have been suggested to be important factors of pathogenic vibrios by causing hemorrhagic septicemia and diarrhea in the host. Many of these hemolysins are well characterized, and genes encoding them have been cloned from V. parahaemolyticus (22, 35), V. cholerae (3, 27), V. hollisae (38), V. mimicus (12), V. vulnificus (38), and V. anguillarum (7).In this study, we describe the cloning and characterization of the hemolysin gene of V. harveyi as a first step towards assessing the role of V. harveyi hemolysin in fish disease. MATERIALS AND METHODSBacterial strains and plasmids. Thirteen V. harveyi isolates from a diverse range of h...

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Response of enteric luminous bacteria to environmental conditions in the gut of the fish

Cited by 19 publications

References 14 publications

Characterization and virulence retention of viable but nonculturable Vibrio harveyi

Characterization and virulence retention of viable but nonculturable Vibrio harveyi

Cysteine protease is a major exotoxin of pathogenic luminousVibrio harveyiin the tiger prawn,Penaeusmonodon

Duplication of Hemolysin Genes in a Virulent Isolate of Vibrio harveyi

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