Aquatic Animal Health Research Unit

Pike Road, AL, United States

Aquatic Animal Health Research Unit

Pike Road, AL, United States
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Yeh H.-Y.,Aquatic Animal Health Research Unit | Klesius P.H.,Aquatic Animal Health Research Unit
Molecular Biology Reports | Year: 2010

The ubiquitin-proteasome cycle is a complex, non-lysosomal biochemical process for intracellular protein degradation. This process involves many enzymes. One enzyme involved in this process is ubiquitin carboxyl-terminal hydrolase L5 (UCHL5), which deubiquitylates the polyubiquitin chain into ubiquitin. In this report, we isolated, sequenced, and characterized the channel catfish UCHL5 cDNA. The complete nucleic acid sequence of the channel catfish UCHL5 cDNA is comprised of 1,357 nucleotides, including an open reading frame, which appears to encode a putative peptide of 329 amino acid residues. The estimated molecular mass and pI of this peptide are 37.6 kDa and 4.84 at pH 7.0, respectively. The degree of conservation of the channel catfish UCHL5 amino acid sequence in comparison to other species ranged from 85% (vs. mouse) to 92% (vs. zebrafish and spotted green pufferfish). The channel catfish UCHL5 transcript was detected by RT-PCR in spleen, head kidney, liver, intestine, skin and gill, suggesting the UCHL5 transcript is constitutively expressed. This research provides important information for further elucidating UCHL5 in the channel catfish ubiquitin-proteasome pathway. © Springer Science+Business Media B.V. 2009.


Shoemaker C.A.,Aquatic Animal Health Research Unit | LaFrentz B.R.,Aquatic Animal Health Research Unit | Klesius P.H.,Aquatic Animal Health Research Unit
Biologicals | Year: 2011

Vibrio vulnificus causes disease in economically important aquaculture raised fish and is an opportunistic human pathogen. This study reports on the isolation of V. vulnificus from diseased hybrid tilapia (Oreochromis niloticus × O. aureus) cultured in a North American water reuse facility. Our objectives were to characterize the isolate using biochemical and molecular methods, develop a disease challenge model, and determine the ability of a formalin inactivated whole-cell vaccine to protect against V. vulnificus. The V. vulnificus isolate recovered was biotype 1, 16S rRNA type B, vcg type C, and vvhA type 2 and caused disease in tilapia held in static salt water (1.5 g/l sea salt). Fish vaccinated with the formalin inactivated whole-cell vaccine responded to vaccination with titers from vaccinated fish ranging from 32 to 64 and titers from non-vaccinated fish ranging from 4 to 8. In two trials, vaccinated tilapia exhibited relative percent survival (RPS) of 73 and 60% following homologous isolate challenge. In two additional trials, vaccinated tilapia exhibited RPS values of up to 88% following challenge with a heterologous isolate; the use of a mineral oil adjuvant enhanced protection. This vaccine may provide an effective means of preventing infections caused by biochemically and genetically diverse V. vulnificus. © 2011.


Dong H.T.,Chulalongkorn University | LaFrentz B.,Aquatic Animal Health Research Unit | Pirarat N.,Chulalongkorn University | Rodkhum C.,Chulalongkorn University
Journal of Fish Diseases | Year: 2015

Flavobacterium columnare is the aetiological agent of columnaris disease and severely affects various freshwater aquaculture fish species worldwide. The objectives of this study were to determine the phenotypic characteristics and genetic variability among F. columnare isolates isolated from red tilapia in Thailand. Forty-four F. columnare isolates were recovered from diseased fish in different geographical locations. The isolates exhibited homologous phenotypic characteristics but exhibited genetic diversity. One isolate was assigned to genomovar I, and the remainder were assigned to genomovar II, indicating the coexistence of these genomovars but predominance of genomovar II. Phylogenetic analysis of the 16S-23S ISR sequences revealed that a subset of the Thai isolates (n = 25) contained a smaller intergenic spacer region (ISR) (523-537 bp) and formed a unique ISR phylogenetic group. Phylogenetic analysis of the 16S rRNA gene supported the unique cluster of Thai isolates. This is the first description of the phenotypic and molecular characteristics of F. columnare isolated from red tilapia in Thailand as well as five isolates of F. columnare derived from other fish species including Nile tilapia, koi carp and striped catfish. © 2015 John Wiley & Sons Ltd.


Liang J.-H.,Jinan University | Fu Y.-W.,Jinan University | Zhang Q.-Z.,Jinan University | Xu D.-H.,Aquatic Animal Health Research Unit | And 2 more authors.
Journal of Agricultural and Food Chemistry | Year: 2015

Ichthyophthirius multifiliis (Ich) is an important ciliate that parasitizes gills and skin of freshwater fish and causes massive fish mortality. In this study, two flavonoids (kuwanons G and O) with anti-Ich activity were isolated by bioassay-guided fractionation from the root bark of Morus alba, an important plant for sericulture. The chemical structures of kuwanons G and O were elucidated by spectroscopic analyses. Kuwanons G and O caused 100% mortality of I. multifiliis theronts at the concentration of 2 mg/L and possessed a median effective concentration (EC50) of 0.8 ± 0.04 mg/L against the theronts. In addition, kuwanons G and O significantly reduced the infectivity of I. multifiliis theronts at concentrations of 0.125, 0.25, 0.5, and 1 mg/L. The median lethal concentrations (LC50) of kuwanons G and O to grass carp were 38.0 ± 0.82 and 26.9 ± 0.51 mg/L, which were approximately 50 and 35 times the EC50 for killing theronts. The results indicate that kuwanons G and O have the potential to become safe and effective drugs to control ichthyophthiriasis. © 2015 American Chemical Society.


Welker T.L.,U.S. Department of Agriculture | Lim C.,Aquatic Animal Health Research Unit | Yildirim-Aksoy M.,Aquatic Animal Health Research Unit | Klesius P.H.,Aquatic Animal Health Research Unit
Aquaculture International | Year: 2012

Juvenile Nile tilapia (Oreochromis niloticus) were fed with diets supplemented with 0 or 6% NaCl for 10 weeks. Tilapia were exposed to approximately 21 mg/l nitrite-N after 5 and 10 weeks of feeding to determine the effect of dietary NaCl supplementation on resistance to nitrite toxicity. Fish were sampled before (baseline, pre-exposure) and after 24 h nitrite exposure to determine the effects of dietary NaCl on mortality, hematology (hematocrit, hemoglobin, and methemoglobin), and plasma electrolyte dynamics (nitrite, chloride, sodium, and potassium). After 10 weeks of feeding, tilapia were also challenged with Streptococcus iniae to determine the effect of sodium chloride on immunity. Tilapia fed with the NaCl-supplemented diet had significantly higher weight gain compared with the control group, which was associated with a significant increase in feed intake in the NaCl group. Mortality from nitrite exposure was lower in tilapia fed with the NaCl-supplemented diet compared with the control group at 5 and 10 weeks, but the differences were not significant. However, dietary NaCl supplementation caused a significant decrease in plasma nitrite levels after nitrite exposure. The dietary reduction in nitrite may be related to the increase in plasma chloride in the 6% NaCl-supplemented fish. A direct link between the effects of dietary NaCl supplementation on methemoglobin (MetHb) could not be established. Tilapia in this study were subjected to acute nitrite toxicity. Dietary sodium chloride may be more effective in protecting against nitrite toxicity at lower levels of nitrite, but the conditions at which it proves to be effective may be limited and requires further investigation. Feeding NaCl to tilapia did not affect susceptibility to S. iniae or immune function, but nitrite exposure cause a stress-related reduction in non-specific immune function. This is the first study to examine the effects of dietary salt on nitrite toxicity in tilapia. © 2011 Springer Science+Business Media B.V. (outside the USA).


Shoemaker C.A.,Aquatic Animal Health Research Unit | LaFrentz B.R.,Aquatic Animal Health Research Unit | Klesius P.H.,Aquatic Animal Health Research Unit
Aquaculture | Year: 2012

Streptococcus iniae, a Gram-positive bacterium, and Vibrio vulnificus, a halophilic Gram-negative bacterium, have been associated with severe disease impacting tilapia aquaculture. Recent reports suggest that both bacteria have been associated independently and concomitantly with disease on commercial farms. Monovalent vaccines have been developed for disease control; however, the most effective delivery strategy has been via intraperitoneal (IP) injection. Due to handling stress and the cost associated with injecting each fish, a better strategy is to combine the monovalent vaccines into bivalent formulations. The objective of the present study was to test the ability of a killed bivalent S. iniae and V. vulnificus vaccine delivered by IP injection at protecting sex reversed hybrid tilapia (Oreochromis niloticus×. Oreochromis aureus) against challenge with each bacterium, independently. In two independent trials, vaccination of tilapia with the bivalent vaccine conferred protective immunity against V. vulnificus and S. iniae as demonstrated by significant differences (P < 0.05) in survival curves between the sham-vaccinated and vaccinated groups. Relative percent survival values ranged from 79 to 89% for V. vulnificus and 69 to 100% for S. iniae following challenge of bivalent vaccinated fish. Use of this bivalent formulation may be a cost-effective strategy to reduce losses in tilapia co-infected with these two important bacterial pathogens. © 2012.


PubMed | Chulalongkorn University, Aquatic Animal Health Research Unit and National Science and Technology Development Agency
Type: Journal Article | Journal: Journal of fish diseases | Year: 2016

Numerous isolates of Flavobacterium columnare were previously recovered from red tilapia, Oreochromis sp., exhibiting columnaris-like disease in Thai farms, and the phenotypic and genetic characteristics were described. The objective of this study was to determine the virulence of two morphotypes (rhizoid and non-rhizoid colonies) of F.columnare and to determine their ability to adhere to and persist in red tilapia fry. The results showed that the typical rhizoid isolate (CUVET1214) was a highly virulent isolate and caused 100% mortality within 24h following bath challenge of red tilapia with three different doses. The non-rhizoid isolate (CUVET1201) was avirulent to red tilapia fry. Both morphotypes adhered to and persisted in tilapia similarly at 0.5 and 6h post-challenge as determined by whole fish bacterial loads. At 24 and 48h post-challenge, fry challenged with the rhizoid morphotype exhibited significantly higher bacterial loads than the non-rhizoid morphotype. The results suggested that an inability of the non-rhizoid morphotype to persist in tilapia fry may explain lack of virulence.


PubMed | Chulalongkorn University and Aquatic Animal Health Research Unit
Type: | Journal: Journal of fish diseases | Year: 2015

Flavobacterium columnare is the aetiological agent of columnaris disease and severely affects various freshwater aquaculture fish species worldwide. The objectives of this study were to determine the phenotypic characteristics and genetic variability among F.columnare isolates isolated from red tilapia in Thailand. Forty-four F.columnare isolates were recovered from diseased fish in different geographical locations. The isolates exhibited homologous phenotypic characteristics but exhibited genetic diversity. One isolate was assigned to genomovar I, and the remainder were assigned to genomovar II, indicating the coexistence of these genomovars but predominance of genomovar II. Phylogenetic analysis of the 16S-23S ISR sequences revealed that a subset of the Thai isolates (n=25) contained a smaller intergenic spacer region (ISR) (523-537bp) and formed a unique ISR phylogenetic group. Phylogenetic analysis of the 16S rRNA gene supported the unique cluster of Thai isolates. This is the first description of the phenotypic and molecular characteristics of F.columnare isolated from red tilapia in Thailand as well as five isolates of F.columnare derived from other fish species including Nile tilapia, koi carp and striped catfish.


PubMed | Aquatic Animal Health Research Unit, National Center for Cool and Cold Water Aquaculture, University of Idaho, Washington State University and 2 more.
Type: Journal Article | Journal: Genome announcements | Year: 2014

The genome sequence of Flavobacterium psychrophilum strain CSF259-93, isolated from rainbow trout (Oncorhynchus mykiss), consists of a single circular genome of 2,900,735bp and 2,701 predicted open reading frames (ORFs). Strain CSF259-93 has been used to select a line of rainbow trout with increased genetic resistance against bacterial cold water disease.


PubMed | Rovira i Virgili University, Aquatic Animal Health Research Unit, Mississippi State University, Alabama Fish Farming Center Greensboro and 2 more.
Type: | Journal: Frontiers in microbiology | Year: 2016

Lineages of hypervirulent

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