Publications

TitleAbstractYear(sorted ascending)
Filter
PMID
Filter
in vitro and in vivo interaction of macrophages from vaccinated and non-vaccinated channel catfish (ictalurus punctatus) to edwardsiella ictaluri.macrophages from catfish vaccinated with an edwardsiella ictaluri vaccine and macrophages from non-vaccinated catfish were used in in vitro and in vivo studies with red-fluorescent e. ictaluri to assess phagocytic ability, reactive oxygen and nitric oxide production and bactericidal activity. in the in vitro experiment, macrophages were harvested from vaccinated and non-vaccinated fish and then exposed to red-fluorescent e. ictaluri. results of this study showed that e. ictaluri can survive and ...200919233291
proteome analysis of edwardsiella ictaluri.edwardsiella ictaluri is a facultative intracellular gram-negative bacterium causing enteric septicemia of catfish (esc), the most prevalent disease affecting farm-raised channel catfish in the united states. despite its economic importance, studies addressing high-throughput proteomics were not possible because of lack of comprehensive protein database. here, we report the first high-throughput proteomics analysis of e. ictaluri using 2-d lc esi ms/ms and 2-de maldi tof/tof ms. proteins identif ...200919253294
identification of centrarchid hepcidins and evidence that 17beta-estradiol disrupts constitutive expression of hepcidin-1 and inducible expression of hepcidin-2 in largemouth bass (micropterus salmoides).hepcidin is a highly conserved antimicrobial peptide and iron-regulatory hormone. here, we identify two hepcidin genes (hep-1 and hep-2) in largemouth bass (micropterus salmoides) and smallmouth bass (micropterus dolomieu). hepcidin-1 contains a putative atcun metal-binding site in the amino-terminus that is missing in hepcidin-2, suggesting that hepcidin-1 may function as an iron-regulatory hormone. both hepcidins are predominately expressed in the liver of largemouth bass, similar to other fis ...200919376234
aroclor 1248 exposure leads to immunomodulation, decreased disease resistance and endocrine disruption in the brown bullhead, ameiurus nebulosus.the brown bullhead ameiurus nebulosus is a species of the family ictaluridae commonly used as a sentinel of environmental contamination. while these fish have been utilized for this purpose in areas contaminated with polychlorinated biphenyls (pcbs), few controlled, laboratory-based studies have been designed to document the effects of pcb mixtures in this species. here, brown bullhead were exposed to the pcb mixture, aroclor 1248, via intraperitoneal injection and the effects on immune function ...200919406486
nod-like subfamily of the nucleotide-binding domain and leucine-rich repeat containing family receptors and their expression in channel catfish.the nlrs (nucleotide-binding domain and leucine-rich repeat containing family receptors) are a recently identified family of pattern recognition receptors in vertebrates. several subfamilies of nlrs have been characterized in human, mouse, and zebrafish, but studies of nlrs in other species, especially teleost species, have been lacking. here we report characterization of five nlrs from channel catfish: nod1, nod2, nlrc3, nlrc5, and nlrx1. structural analysis indicated that the genes were organi ...200919414032
expression analysis of selected immune-relevant genes in channel catfish during edwardsiella ictaluri infection.channel catfish ictalurus punctatus were intraperitoneally challenged with the bacterium edwardsiella ictaluri (the causative agent of enteric septicemia of catfish), and the expression of genes presumed to function in the inducible innate defense was evaluated. end-binding protein 1 (eb1), beta1-integrin, natural-resistance-associated macrophage protein (nramp), heat shock protein 70 (hsp70), serum amyloid p (sap), and transferrin gene expression profiles were determined using quantitative reve ...200919485123
chemical and electroporated transformation of edwardsiella ictaluri using three different plasmids.transfer of dna by conjugation has been the method generally used for genetic manipulation of edwardsiella ictaluri because, previously, attempts to transform e. ictaluri by the uptake of naked dna have apparently failed. we report here the successful transformation of seven strains of e. ictaluri using electroporation and two different chemical procedures [conventional calcium chloride (cacl(2)) and 'one-step' (polyethylene glycol, dimethyl sulfoxide and mgso(4)) protocols]. seven strains of e. ...200919594620
genotyping of edwardsiella ictaluri isolates in japan using amplified-fragment length polymorphism analysis.the major objective of the present study was to clarify genetic relationship of isolates of edwardsiella ictaluri in japan, which was first found from ayu plecoglossus altivelis in japanese rivers in 2007.200919674293
combined immersion and oral vaccination of vietnamese catfish (pangasianodon hypophthalmus) confers protection against mortality caused by edwardsiella ictaluri.edwardsiella ictaluri septicemia occurs worldwide and causes high mortality and considerable economic damage to the catfish industry especially in vietnam and the usa. to control edwardsiella septicemia farmers extensively use antibiotics and various vaccination methods. vaccination with inactivated vaccines has come with variable efficacy. in this trial the results of an approach of controlling edwardsiella septicemia of tra catfish (pangasianodon hypophthalmus) in vietnam through vaccination v ...200919747976
edwardsiella ictaluri encodes an acid-activated urease that is required for intracellular replication in channel catfish (ictalurus punctatus) macrophages.genomic analysis indicated that edwardsiella ictaluri encodes a putative urease pathogenicity island containing the products of nine open reading frames, including urea and ammonium transporters. in vitro studies with wild-type e. ictaluri and a ureg::kan urease mutant strain indicated that e. ictaluri is significantly tolerant of acid conditions (ph 3.0) but that urease activity is not required for acid tolerance. growth studies demonstrated that e. ictaluri is unable to grow at ph 5 in the abs ...200919749068
identification of edwardsiella ictaluri and e. tarda by species-specific polymerase chain reaction targeted to the upstream region of the fimbrial gene.phylogenetic analysis of nine strains of edwardsiella ictaluri and eight strains of e. tarda (six typical motile strains and two atypical nonmotile strains) isolated from diseased fish was performed using the upstream region of the fimbrial gene cluster. strains of e. ictaluri and e. tarda were significantly clustered into separate groups. moreover, atypical e. tarda strains were clustered into a different group from the other strains. three polymerase chain reaction (pcr) primer sets for differ ...200919873834
role of nonspecific cytotoxic cells in bacterial resistance: expression of a novel pattern recognition receptor with antimicrobial activity.pattern recognition receptors (prr) recognize invariant bacterial, viral, protozoan and certain synthetic ligands. prr may be expressed as outer membrane (or endosomal) or cytosolic proteins and function to signal cell activation processes during inflammation responses. in the present study, a novel membrane receptor, ncc cationic antimicrobial protein-1 (ncamp-1), is described that is expressed on nonspecific cytotoxic cell (ncc) membranes and is found in granule extracts from these cells. in r ...200919007992
proteomic analysis of head kidney tissue from high and low susceptibility families of channel catfish following challenge with edwardsiella ictaluri.a study was performed to compare proteomic profiles of channel catfish from families with high and low susceptibility to edwardsiella ictaluri following an immersion challenge. total protein was isolated from head kidney samples, collected at 2 and 6h postexposure, and analyzed by 2-d-gel electrophoresis coupled with peptide mass fingerprint analysis by matrix-assisted laser desorption/ionization and time of flight tandem mass spectrometry. comparisons were made between proteomic profiles from i ...200919028110
inca/c plasmid-mediated florfenicol resistance in the catfish pathogen edwardsiella ictaluri. 200919029319
channel catfish, ictalurus punctatus, cysteine proteinases: cloning, characterisation and expression of cathepsin h and l.the antigen recognition by the host immune system is a complex biochemical process that requires a battery of enzymes. cathepsins are one of the enzyme superfamilies involved in antigen degradation. we observed the up-regulation of catfish cathepsin h and l transcripts during the early stage of edwardsiella ictaluri infection in preliminary studies, and speculated that cathepsin h and l may play roles in infection. we identified, sequenced and characterized the complete channel catfish cathepsin ...200919084602
effect of common aquaculture chemicals against edwardsiella ictaluri and e. tarda.edwardsiellosis is an important bacterial infection of freshwater and marine fishes. edwardsiella ictaluri causes enteric septicemia of catfish, and e. tarda causes emphysematous putrefactive disease of catfish and fish gangrene in various species; these diseases have considerable economic effects on the aquaculture industry. in addition, e. tarda is an important zoonotic pathogen. thus, the reduction or elimination of these pathogens from an aquarium or aquaculture facility is imperative. this ...201021413505
plant natural compounds with antibacterial activity towards common pathogens of pond-cultured channel catfish (ictalurus punctatus).the bacteria edwardsiella ictaluri and flavobacterium columnare cause enteric septicemia and columnaris disease, respectively, in channel catfish (ictalurus punctatus). natural therapeutants may provide an alternative to current management approaches used by producers. in this study, a rapid bioassay identified plant compounds as potential therapeutants. chelerythrine chloride and ellagic acid were the most toxic toward e. ictaluri, with 24-h ic50 of 7.3 mg/l and 15.1 mg/l, respectively, and mic ...201022069655
verification of an edwardsiella ictaluri-specific diagnostic pcr.to verify the specificity of a pcr assay for the identification and diagnosis of edwardsiella ictaluri.201020002568
sequence analysis, characterization and tissue distribution of channel catfish (ictalurus punctatus rafinesque, 1818) myeloperoxidase cdna.myeloperoxidase (ec 1.11.1.7), a heme-containing lysosomal glycoprotein, is found predominantly in azurophilic granules of neutrophils. this enzyme upon activation catalyzes hydrogen peroxide in the presence of various halide ions to form hypohalous acids. subsequently, these reagents are able to kill the invading microorganisms. in this study, we report the identification, characterization and expression analysis of the channel catfish myeloperoxidase transcript. the full-length nucleotide sequ ...201020034575
identification of in vitro upregulated genes in a modified live vaccine strain of edwardsiella ictaluri compared to a virulent parent strain.using pcr-select subtractive cdna hybridization technique, 41 in vitro expressed sequence tags (ests) were isolated from a modified live vaccine strain (aquavac-esc, formerly re-33) vs a virulent parent strain (eilo) of edwardsiella ictaluri. transcriptional levels of the 41 in vitro ests in the vaccine strain and the virulent strain were then evaluated by quantitative pcr (qpcr). the qpcr results revealed that 33 ests were consistently upregulated at least 3-fold in the modified live vaccine st ...201020034669
isolation and characterization of sap and crp, two pentraxins from pangasianodon (pangasius) hypophthalmus.from the serum of pangasianodon hypophthalmus, two proteins were isolated by affinity chromatography on sepharose and phosphorylcholine-sepharose. their binding on the affinity matrices critically depends on the presence of ca2+ ions. n-terminal sequencing and sequencing of internal tryptic peptides identified the proteins as pentraxins and from their binding properties they are identified as sap (serum amyloid p component) and crp (c-reactive protein). per ml serum, 36 microg sap and 56 microg ...201020109557
identification, phylogenetic relationships, characterization and gene expression patterns of six different annexins of channel catfish (ictalurus punctatus rafinesque, 1818).annexins are ca(2+)-dependent phospholipid-binding proteins. they are ubiquitous in living organisms and are involved in many cellular processes. in the course of studying edwardsiella ictaluri pathogenesis in channel catfish, we identified that six annexin expressed sequence tags (a1, a2, a4, a5, a6 and a11) were up-regulated at the early stage of infection. in this study, we cloned and characterized these transcripts. the full-length nucleic acid sequences of channel catfish annexins ranges fr ...201020227769
molecular characterization and gene expression of the channel catfish ferritin h subunit after bacterial infection and iron treatment.ferritins are the major iron storage protein in the cytoplasm of cells, responsible for regulating levels of intracellular iron. ferritin genes are widely distributed in both prokaryotes and eukaryotes. in mammals, ferritin molecules are composed of heavy- (h) and light- (l) chain subunits; amphibian genomes contain three ferritin-type genes (h; middle, m; and l subunits); and teleost genomes to date contain h and m subunits. the objective of this study was to characterize the ferritin h gene in ...201020336795
expression profiles of toll-like receptors in anterior kidney of channel catfish, ictalurus punctatus (rafinesque), acutely infected by edwardsiella ictaluri.using quantitative pcr (qpcr), the relative transcriptional levels of five toll-like receptors (tlr2, tlr3, tlr5, tlr20a and tlr21) were studied in the channel catfish, ictalurus punctatus (rafinesque), under uninfected and acutely infected conditions [1-, 2-, 4-, 6-, 12-, 24-, 36- and 48-h post-injection (hpi)]. under uninfected conditions, the transcriptional levels of the five tlrs were significantly lower than that of 18s rrna (p < 0.001). qpcr results also revealed that the transcriptional ...201020384909
experimental challenge studies in vietnamese catfish, pangasianodon hypophthalmus (sauvage), exposed to edwardsiella ictaluri and aeromonas hydrophila.the two main diseases in the pangasius catfish industry are bacillary necrosis of pangasianodon (bnp) and motile aeromonas septicaemia (mas), where the aetiological agents have been identified as edwardsiella ictaluri and aeromonas hydrophila, respectively. in this study, apparently healthy pangasianodon hypophthalmus were exposed to e. ictaluri, a. hydrophila or both bacterial species by intraperitoneal injection or immersion. there were 20 fish per treatment group, and the bacterial isolates u ...201020572902
importance of skin abrasion as a primary site of adhesion for edwardsiella ictaluri and impact on invasion and systematic infection in channel catfish ictalurus punctatus.the route of entry of edwardsiella ictaluri into its catfish host has been a subject of investigation since the pathogen was first discovered. there is evidence to support entry through the intestinal tract, the nares, and the gills. here, we evaluated the role of skin abrasion through a series of experimental challenges using bioluminescent e. ictaluri carrying the plasmid paklux1. our results show that e. ictaluri is able to colonize abrasion sites on catfish skin and that catfish with abrasio ...201020869817
molecular responses of calreticulin genes to iron overload and bacterial challenge in channel catfish (ictalurus punctatus).infection and inflammation are often accompanied by oxidative stress caused by the accumulation of reactive oxygen species which can be deleterious to the health of the host. antioxidant defense mechanisms and components are crucial in limiting cellular and tissue-level damage and restoring homeostasis. in mammals, calreticulin is a 46-kda multifunctional calcium binding protein of the endoplasmic reticulum that has many critical functions in the eukaryotic cell including regulation of intracell ...201021093478
the aspartate-semialdehyde dehydrogenase of edwardsiella ictaluri and its use as balanced-lethal system in fish vaccinology.asda mutants of gram-negative bacteria have an obligate requirement for diaminopimelic acid (dap), which is an essential constituent of the peptidoglycan layer of the cell wall of these organisms. in environments deprived of dap, i.e., animal tissues, they will undergo lysis. deletion of the asda gene has previously been exploited to develop antibiotic-sensitive strains of live attenuated recombinant bacterial vaccines. introduction of an asd(+) plasmid into a δasda mutant makes the bacterial st ...201021209920
identification and expression profile of multiple genes in the anterior kidney of channel catfish induced by modified live edwardsiella ictaluri vaccination.using pcr-select subtractive cdna hybridization technique, 57 expressed sequence tags (ests) were isolated from 240 clones of a modified live edwardsiella ictaluri vaccinated vs. sham-vaccinated channel catfish anterior kidney subtractive library. the transcription levels of the 57 ests in response to e. ictaluri vaccination were then evaluated by quantitative pcr (qpcr). of the 57 ests, 43 were induced at least 2-fold higher in all three vaccinated fish compared to unvaccinated control fish. of ...201019800135
structure and expression of transferrin gene of channel catfish, ictalurus punctatus.transferrin is important in iron metabolism and has been reported to be involved in disease defence responses after bacterial infection. in this study, we identified, sequenced, and characterized the transferrin gene from channel catfish, ictalurus punctatus. the catfish transferrin gene was similar to those of other vertebrate species with 17 exons and 16 introns. sequence analysis indicated the presence of the two duplicated lobes, each containing two sub-domains separated by a cleft harboring ...201019837170
comparative genomic analysis of bacteriophages specific to the channel catfish pathogen edwardsiella ictaluri.the bacterial pathogen edwardsiella ictaluri is a primary cause of mortality in channel catfish raised commercially in aquaculture farms. additional treatment and diagnostic regimes are needed for this enteric pathogen, motivating the discovery and characterization of bacteriophages specific to e. ictaluri.201121214923
molecular responses of ceruloplasmin to edwardsiella ictaluri infection and iron overload in channel catfish (ictalurus punctatus).ceruloplasmin is a serum ferroxidase that carries more than 90% of the copper in plasma and has documented roles in iron homeostasis as well as antioxidative functions. in our previous studies, it has been shown that the ceruloplasmin gene is strongly up-regulated in catfish during challenge with edwardsiella ictaluri. however, little is known about the function of this gene in teleost fish. the objective of this study, therefore, was to characterize the ceruloplasmin gene from channel catfish, ...201121220026
microfibrillar-associated protein 4 (mfap4) genes in catfish play a novel role in innate immune responses.the lectin pathway of the complement system is characterized by two groups of soluble pattern recognition molecules, mannose-binding lectins (mbls) and ficolins. these molecules recognize and bind carbohydrates in pathogens and activate complement leading to opsonization, leukocyte activation, and direct pathogen killing. while mbls have been reported in many fish species, ficolins do not appear to be present in the teleost lineage, despite their importance in invertebrate and higher vertebrate ...201121232551
effect of short-term feeding duration of diets containing commercial whole-cell yeast or yeast subcomponents on immune function and disease resistance in channel catfish, ictalurus punctatus.juvenile channel catfish, ictalurus punctatus, were fed diets supplemented with yeast or yeast subcomponents (yys) as commercial preparations of ß-glucan (macrogard(®) and betagard a(®) ), mannan oligosaccharide (bio-mos(®) aqua grade), or whole-cell saccharomyces cerevisiae (levucell sb20(®) ) at the manufacturers' recommended levels. fish were fed experimental diets for 1 or 2 weeks prior to disease challenge (pre-challenge feeding periods) and sampled at the end of each feeding period to meas ...201121320174
phenotype, virulence and immunogenicity of edwardsiella ictaluri cyclic adenosine 3',5'-monophosphate receptor protein (crp) mutants in catfish host.edwardsiella ictaluri is an enterobacteriaceae that causes lethal enteric septicemia in catfish. being a mucosal facultative intracellular pathogen, this bacterium is an excellent candidate to develop immersion-oral live attenuated vaccines for the catfish aquaculture industry. deletion of the cyclic 3',5'-adenosine monophosphate (camp) receptor protein (crp) gene in several enterobacteriaceae has been utilized in live attenuated vaccines for mammals and birds. here we characterize the crp gene ...201122015784
the edwardsiella ictaluri type iii secretion system is regulated by ph and phosphate concentration through esra, esrb, and esrc.a recently described edwardsiella ictaluri type iii secretion system (t3ss) with functional similarity to the salmonella pathogenicity island-2 t3ss is required for replication in channel catfish head-kidney-derived macrophages (hkdm) and virulence in channel catfish. quantitative pcr and western blotting identified low ph and phosphate limitation as conducive to expression of the e. ictaluri t3ss, growth conditions that mimic the phagosomal environment. mutagenesis studies demonstrated that exp ...201121551284
molecular characterization and expression analysis of the channel catfish cathepsin d genes.cathepsin d is a lysosomal aspartic proteinase that participates in various degradation functions of the cell. in this study, we characterized the cathepsin d genes in channel catfish and found two genes encoding catfish cathepsin d, referred to as cathepsin d1 and d2 genes. these two genes are highly similar in genomic structure and organization, sharing a moderate level of amino acid sequence similarity (56%). genomic southern analysis suggested the presence of a single copy of each of the cat ...201121558007
use of fluorescent immuno-chemistry for the detection of <em>edwardsiella ictaluri</em> in channel catfish (<em>i. punctatus</em>) samples.while edwardsiella ictaluri is a major pathogen of channel catfish ictalurus punctatus and has been discovered nearly three decades ago (1,2), so far, to the best of these authors' knowledge, no method has been developed to allow for the in situ visualization of the bacteria in histological sections. while bacterial localization has been determined in vivo in previous studies using plate counts (3), radiometric labeled (4), or bioluminescent bacteria (5), most of these studies have only been per ...201121610669
development of a novobiocin-resistant edwardsiella ictaluri as a novel vaccine in channel catfish (ictalurus punctatus).the efficacy of a novel attenuated edwardsiella ictaluri vaccine (b-50348) was determined in channel catfish (ictalurus punctatus) by bath immersion and intraperitoneal (ip) injection. the vaccine was developed from a virulent strain of e. ictaluri (al93-58) through selection for novobiocin resistance. when channel catfish (average weight 10 g) were ip injected with 4.2 +ù 10ôüâ colony-forming units (cfu) of the attenuated vaccine b-50348, no fish died. however, when the same age and size matche ...201121699944
expression of leptin-like peptide (llp) mrna in channel catfish (ictalurus punctatus) is induced by exposure to edwardsiella ictaluri but is independent of energy status.leptin is a key pleiotropic cytokine involved in regulation of energy homeostasis and immunity in mammals. in channel catfish, the presence of a partial messenger rna sequence that encodes a leptin-like peptide (llp) has been identified and investigated. the objectives of the present studies were to clone and characterize full-length catfish llp gene, examine tissue expression of llp mrna, and determine effects of prolonged fasting and exposure to edwardsiella ictaluri (e. ictaluri), the bacteri ...201121741381
pathogen recognition receptors in channel catfish: i. identification, phylogeny and expression of nod-like receptors.innate immune system plays a significant role in all multicellular organisms. the key feature of the system is its ability to recognize and respond to invading microorganisms. vertebrates including teleost fish have evolved an array of pathogen recognition receptors (prrs) for detecting and responding to various pathogen-associated molecular patterns (pamps), including toll-like receptors (tlrs), nucleotide-binding domain, leucine-rich repeat containing receptors (nlrs), and the retinoic acid in ...201122200599
an outer membrane porin protein modulates phage susceptibility in edwardsiella ictaluri.bacteriophages φeiau and φeidwf are lytic to the catfish pathogen edwardsiella ictaluri. the e. ictaluri host factors that modulate phage-host interactions have not been described previously. this study identified eleven unique e. ictaluri host factors essential for phage infection by screening a transposon mutagenized library of two e. ictaluri strains for phage-resistant mutants. two mutants were isolated with independent insertions in the omplc gene that encodes a putative outer membrane por ...201122135098
Genetic relationships of Edwardsiella strains isolated in China aquaculture revealed by rep-PCR genomic fingerprinting and investigation of Edwardsiella virulence genes.The aim of this study was to classify Edwardsiella strains isolated from China aquaculture based on biochemical and molecular methods.201121974718
modified live edwardsiella ictaluri vaccine, aquavac-esc, lacks multidrug resistance plasmids.plasmid-mediated antibiotic resistance was first discovered in edwardsiella ictaluri in the early 1990s, and in 2007 an e. ictaluri isolate harboring an inca/c plasmid was recovered from a moribund channel catfish ictalurus punctatus infected with the bacterium. due to the identification of multidrug resistance plasmids in aquaculture and their potential clinical importance, we sought to determine whether the modified live e. ictaluri vaccine strain in aquavac-esc harbors such plasmids, so that ...201122372247
a real-time polymerase chain reaction assay for quantification of edwardsiella ictaluri in catfish pond water and genetic homogeneity of diagnostic case isolates from mississippi.a quantitative polymerase chain reaction (qpcr) assay was developed for the detection and quantification of edwardsiella ictaluri in channel catfish ictalurus punctatus pond water using modifications to a published e. ictaluri-specific qpcr assay and previously established protocols for the molecular detection of myxozoan parasites in catfish ponds. genomic dna equivalents indicative of the number of bacteria in a sample were determined and standard curves correlating to bacterial numbers were e ...201122372245
global transcription analysis of vaccinated channel catfish following challenge with virulent edwardsiella ictaluri.to determine the identities of genes involved in either innate or adaptive immunity, microarray analysis of 65,182 unigene transcripts were performed to compare gene expression in vaccinated channel catfish after challenge with a virulent edwardsiella ictaluri compared to that in sham-vaccinated fish without challenge. with a filter of false-discovery rate less than 0.05 and fold change greater than 2, a total of 167 functionally known unique transcripts were found to be up-regulated, whereas 40 ...201222365332
arginine and glutamine supplementation to culture media improves the performance of various channel catfish immune cells.specific components of both the innate and adaptive immune systems of channel catfish were evaluated after supplementation of culture media with arginine (arg) and/or glutamine (gln). primary cell cultures of head-kidney macrophages (mø) were used for phagocytic and bactericidal assays against edwardsiella ictaluri. additionally, proliferation assays were conducted with naïve peripheral blood lymphocytes (pbl) exposed to non-specific mitogens. to indirectly assess amino acid utilization of both ...201222326940
expression profiles of seven channel catfish antimicrobial peptides in response to edwardsiella ictaluri infection.using quantitative polymerase chain reaction (qpcr), the relative transcriptional levels of seven channel catfish antimicrobial peptide (amp) genes (nk-lysin type 1, nk-lysin type 2, nk-lysin type 3, bactericidal permeability-increasing protein, cathepsin d, hepcidin and liver-expressed amp 2) in response to edwardsiella ictaluri infection were determined. none of the amp genes tested was significantly upregulated at 2 h post-infection. hepcidin was the only one that was significantly (p<0.05) u ...201222324346
ichthyophthirius multifiliis as a potential vector of edwardsiella ictaluri in channel catfish.there is limited information on whether parasites act as vectors to transmit bacteria in fish. in this trial, we used ichthyophthirius multifiliis and fluorescent edwardsiella ictaluri as a model to study the interaction between parasite, bacterium, and fish. the percentage (23-39%) of theronts fluorescing after exposure to e. ictaluri was significantly higher than control theronts (~ 6%) using flow cytometry. theronts exposed to e. ictaluri at 4 × 10(7)  cfu ml(-1) showed a higher percentage (~ ...201222309484
global gene expression in channel catfish after vaccination with an attenuated edwardsiella ictaluri.to understand the global gene expression in channel catfish after immersion vaccination with an attenuated edwardsiella ictaluri (aquavac-esc™), microarray analysis of 65,182 unigene transcripts was performed. with a filter of false-discovery rate less than 0.05 and fold change greater than 2, a total of 52 unique transcripts were found to be upregulated in vaccinated fish at 48 h post vaccination, whereas a total of 129 were downregulated. the 52 upregulated transcripts represent genes with put ...201222245589
edwardsiella ictaluri luxs: activity, expression, and involvement in pathogenicity.edwardsiella ictaluri is a gram-negative bacterium and the causative agent of enteric septicemia of catfish. in this study, we examined the expression and function of the luxs from a pathogenic e. ictaluri strain, 1901. j901 was found to produce autoinducer 2 (ai-2) activity that maximized at mid-logarithmic phase and was enhanced by glucose and repressed by high temperature. consistently, a luxs gene (luxsei) was identified in j901, whose expression was regulated by cell density, glucose, and t ...201223484409
isolation and identification of flavobacterium columnare and streptococcus iniae antibacterial compounds from the terrestrial plant atraphaxis laetevirens.columnaris disease, enteric septicemia of catfish, and streptococcosis are common bacterial diseases of certain freshwater fish and are caused by flavobacterium columnare , edwardsiella ictaluri , and streptococcus iniae , respectively. during the process of evaluating several species of plants to isolate and identify compounds with toxicity against these bacteria, a promising extract from the aerial parts of the terrestrial plant atraphaxis laetevirens (ledeb.) jaub. et spach (polygonaceae juss ...201223030835
rag1-/- mutant zebrafish demonstrate specific protection following bacterial re-exposure.recombination activation gene 1 deficient (rag1(-/-)) mutant zebrafish have a reduced lymphocyte-like cell population that lacks functional b and t lymphocytes of the acquired immune system, but includes natural killer (nk)-like cells and non-specific cytotoxic cells (ncc) of the innate immune system. the innate immune system is thought to lack the adaptive characteristics of an acquired immune system that provide enhanced protection to a second exposure of the same pathogen. it has been shown t ...201222970222
a new zebrafish model of oro-intestinal pathogen colonization reveals a key role for adhesion in protection by probiotic bacteria.the beneficial contribution of commensal bacteria to host health and homeostasis led to the concept that exogenous non-pathogenic bacteria called probiotics could be used to limit disease caused by pathogens. however, despite recent progress using gnotobiotic mammal and invertebrate models, mechanisms underlying protection afforded by commensal and probiotic bacteria against pathogens remain poorly understood. here we developed a zebrafish model of controlled co-infection in which germ-free zebr ...201222911651
spleen index and mannose-binding lectin levels in four channel catfish families exhibiting different susceptibilities to flavobacterium columnare and edwardsiella ictaluri.edwardsiella ictaluri and flavobacterium columnare are two bacterial pathogens that affect channel catfish ictalurus punctatus aquaculture. at the catfish genetics research unit (u.s. department of agriculture, agricultural research service), some progress has been made in selectively breeding for resistance to e. ictaluri; however, the susceptibility of these families to f. columnare is not known. our objectives were to obtain baseline information on the susceptibility of channel catfish famili ...201222870893
edwardsiella ictaluri as the causative agent of mortality in cultured nile tilapia.edwardsiella ictaluri was consistently isolated from the spleens, livers, and head kidneys of diseased nile tilapia oreochromis niloticus from a farm experiencing mortality events in several culture ponds. we describe the first published outbreak of e. ictaluri-induced edwardsiellosis in nile tilapia. pure cultures of the isolated bacteria were characterized both biochemically and molecularly. biochemical analysis was performed using the api-20e and rapid one systems, and antimicrobial susceptib ...201222838078
intraspecific diversity of edwardsiella ictaluri isolates from diseased freshwater catfish, pangasianodon hypophthalmus (sauvage), cultured in the mekong delta, vietnam.a molecular epidemiology study was conducted on 90 edwardsiella ictaluri isolates recovered from diseased farmed freshwater catfish, pangasianodon hypophthalmus, cultured in the mekong delta, vietnam. thirteen isolates of e. ictaluri derived from diseased channel catfish, ictalurus punctatus, cultured in the usa were included for comparison. all the e.ictaluri isolates tested were found to be biochemically indistinguishable. a repetitive (rep)-pcr using the single (gtg)(5) primer was shown to po ...201222804634
synergies between vaccination and dietary arginine and glutamine supplementation improve the immune response of channel catfish against edwardsiella ictaluri.channel catfish was used to investigate the enhancement of vaccine efficacy following dietary supplementation with arginine (arg, 4% of diet), glutamine (gln, 2% of diet), or a combination of both. after vaccination against edwardsiella ictaluri, humoral and cellular immune responses, along with lymphoid organ responses were evaluated. e. ictaluri-specific antibody titers in plasma were higher (p < 0.05) in fish fed the supplemented diets compared to those fed the basal diet as early as 7 d post ...201222728565
effect of ichthyophthirius multifiliis parasitism on the survival, hematology and bacterial load in channel catfish previously exposed to edwardsiella ictaluri.the effect of ichthyophthirius multifiliis (ich) parasitism on survival, hematology and bacterial load in channel catfish, ictalurus punctatus, previously exposed to edwardsiella ictaluri was studied. fish were exposed to e. ictaluri 1 day prior to ich in the following treatments: (1) infected by e. ictaluri and ich at 2,500 theronts/fish; (2) infected by e. ictaluri only; (3) infected by ich at 2,500 theronts/fish only; and (4) non infected control. mortality was significantly higher in fish pr ...201222699968
effect of berberine hydrochloride on grass carp ctenopharyngodon idella serum bactericidal activity against edwardsiella ictaluri.bactericidal activity of grass carp (ctenopharyngodon idella) serum was significantly enhanced when pre-treated with 15 mg l⁻¹ or 3 mg l⁻¹ of berberine hydrochloride, an effective component of several commonly used herbal medicines in aquaculture. the complement consumption experiment demonstrated that berberine hydrochloride can certainly activate fish complement system. the results of both experiments suggested that berberine hydrochloride could enhance the serum bactericidal activity in grass ...201222521421
the effect of adjuvant and microbial challenge on the expression of antimicrobial polypeptides in channel catfish (ictalurus punctatus).while antimicrobial polypeptides (ampps) are increasingly recognized as one of the most important components of innate immunity, there is very little information in vertebrates that documents their upregulation to levels that are microbicidal in vivo. here we demonstrate that intraperitoneal injection of either freund's complete adjuvant (fca) or live tetrahymena pyriformis (a parasitic ciliate) upregulated ampp expression in channel catfish skin. fca induced significant upregulation of total an ...201222507196
early interactions of edwardsiella ictaluri, with pangasianodon catfish and its invasive ability in cell lines.commercial pangasianodon catfish production is heavily impacted by bacillary necrosis of pangasius (bnp) caused by edwardsiella ictaluri. this study aimed to investigate the early bacterium-host interactions following immersion challenge and to compare the retrieved data with the invasion ability of the used isolates in fish cell lines. firstly, pangasianodon hypophthalmus fingerlings were challenged via immersion using e. ictaluri isolate ho2 or 223. at different times post inoculation, fish we ...201222422551
enhanced susceptibility of channel catfish to the bacterium edwardsiella ictaluri after parasitism by ichthyophthirius multifiliis.bacterium edwardsiella ictaluri and parasite ichthyophthirius multifiliis (ich) are two common pathogens of cultured fish. the objective of this study was to evaluate the susceptibility of channel catfish ictalurus punctatus to e. ictaluri and determine bacterial loads in different fish organs after parasitism by ich. fish received the following treatments: (1) infected by i. multifiliis at 5000 theronts/fish and exposed to e. ictaluri; (2) infected by i. multifiliis alone; (3) exposed to e. ict ...201222397934
identification of bacillus strains for biological control of catfish pathogens.bacillus strains isolated from soil or channel catfish intestine were screened for their antagonism against edwardsiella ictaluri and aeromonas hydrophila, the causative agents of enteric septicemia of catfish (esc) and motile aeromonad septicaemia (mas), respectively. twenty one strains were selected and their antagonistic activity against other aquatic pathogens was also tested. each of the top 21 strains expressed antagonistic activity against multiple aquatic bacterial pathogens including ed ...201223029244
rna-seq analysis of mucosal immune responses reveals signatures of intestinal barrier disruption and pathogen entry following edwardsiella ictaluri infection in channel catfish, ictalurus punctatus.the mucosal surfaces of fish (gill, skin, gastrointestinal tract) are important sites of bacterial exposure and host defense mechanisms. in mammalian systems, the intestinal epithelium is well characterized as both a selectively permeable barrier regulated by junctional proteins and as a primary site of infection for a number of enteric pathogens including viruses, bacteria, and parasites. the causative bacterium of enteric septicemia of catfish, edwardsiella ictaluri, is believed to gain entry ...201222366064
alternative complement pathway of channel catfish (ictalurus punctatus): molecular characterization, mapping and expression analysis of factors bf/c2 and df.the complement system is important in both innate and adaptive host defense against microbial infection in vertebrates. it contains three pathways: the classical, alternative, and lectin pathways. complement component factors b and d are two crucial proteases in the alternative pathway. in this study, the genes of complement factors bf/c2 and df from channel catfish, ictalurus punctatus were identified and characterized. two complement factor b-related genes, bf/c2a and bf/c2b, and factor d gene ...201222138130
Secreted glyceraldehyde-3-phosphate dehydrogenase as a broad spectrum vaccine candidate against microbial infection in aquaculture.Aims: Subcellullar localizations and cross-immunities of GAPDHs from six common pathogenic bacteria in aquaculture were investigated. Methods and Results: Subcellullar localizations of GAPDHs of Edwardsiella tarda EIB202, Edwardsiella ictaluri ATCC33202, Aeromonas hydrophila LSA34, Vibrio anguillarum MVM425, Vibrio alginolyticus EPGS020401 and Vibrio harveyi VIB647 were analysed with Western blotting, indirect immunofluorescence and flow cytometry examinations. Immunoprotections of different r ...201222017642
molecular characterization of three l-type lectin genes from channel catfish, ictalurus punctatus and their responses to edwardsiella ictaluri challenge.l-type lectins have a leguminous lectin domain and can bind to high-mannose type oligosaccharides. in the secretory pathway, l-type lectins play crucial roles in selective protein trafficking, sorting and targeting. three l-type lectins were cloned in the channel catfish, ictalurus punctatus, the 53 kda endoplasmic reticulum er-golgi intermediate compartment protein (ergic-53), the vesicular integral protein of 36 kda (vip36) and vip36-like. phylogenetic analysis indicated that the catfish genes ...201222245838
genome sequence of edwardsiella ictaluri 93-146, a strain associated with a natural channel catfish outbreak of enteric septicemia of catfish.edwardsiella ictaluri is the cause of extensive mortalities and economic losses to the channel catfish industry of the southeast united states. here we report the complete genome of edwardsiella ictaluri 93-146. whole-genome sequence analysis of e. ictaluri provides a tool for understanding the genomic regions specific to the species and the edwardsiella genus.201222247535
bactericidal efficacy of elevated ph on fish pathogenic and environmental bacteria.ship ballast water is a recognized medium for transfer and introductions of nonindigenous species. there is a need for new ballast water treatment methods that effectively and safely eliminate or greatly minimize movements of these species. the present study employed laboratory methods to evaluate the bactericidal efficacy of increased ph (ph 10.0-12.0) for exposure durations of up to 72 h to kill a variety of gram-negative and gram-positive bacteria including fish pathogens (aeromonas spp., yer ...201225685439
fur-regulated iron uptake system of edwardsiella ictaluri and its influence on pathogenesis and immunogenicity in the catfish host.the ability of bacterial pathogens to take up iron from the host during infection is necessary for their multiplication within the host. however, host high-affinity iron binding proteins limit levels of free iron in fluids and tissues. to overcome this deficiency of iron during infection, bacterial pathogens have developed iron uptake systems that are upregulated in the absence of iron, typically tightly controlled by the ferric uptake regulator (fur) protein. the iron uptake system of edwardsie ...201222615248
detection of quorum sensing signal molecules in edwardsiella ictaluri ei-151.edwardsiella ictaluri is a gram-negative pathogenic bacterium in the family enterobacteriaceae that causes enteric septicemia of catfish, which has become a significant problem in the aquaculture of striped catfish (pangasianodon hypophthalmus) in vietnam. in this study, a bacterium designated as ei-151 was isolated from diseased striped catfish and proved to be virulent. based on 16s rdna sequencing and phenotypic tests, the pathogenic bacterium was identified as edw. ictaluri. the presence of ...201224293714
edwardsiellosis caused by edwardsiella ictaluri in laboratory populations of zebrafish danio rerio.we report the first cases of edwardsiella ictaluri causing epizootics in laboratory populations of zebrafish danio rerio. edwardsiella ictaluri is primarily recognized as a disease of catfish species and is known to cause an economically important bacterial disease of farm-raised catfish in the usa and abroad; however, it has been isolated on occasion from 10 other genera of nonictalurid fishes. we isolated e. ictaluri from moribund zebrafish held in quarantine at two different universities in t ...201323865817
mechanisms of intrinsic resistance to antimicrobial peptides of edwardsiella ictaluri and its influence on fish gut inflammation and virulence.the genus edwardsiella comprises a genetically distinct taxon related to other members of the family enterobacteriaceae. it consists of bacteria differing strongly in their biochemical and physiological features, natural habitats, and pathogenic properties. intrinsic resistance to cationic antimicrobial peptides (camps) is a specific property of the genus edwardsiella. in particular, edwardsiella ictaluri, an important pathogen of the catfish (ictalurus punctatus) aquaculture and the causative a ...201323676433
comparison of vietnamese and us isolates of edwardsiella ictaluri.we compared edwardsiella ictaluri from striped catfish in vietnam with us channel catfish isolates. biochemical analyses and sequencing of the 16s rrna gene confirmed that the vietnamese isolates were e. ictaluri. comparison using rep-pcr fingerprinting demonstrated no significant differences between the isolates, but plasmid analysis indicated that the vietnamese isolates grouped into 4 plasmid profiles, each different from the typical pei1 and pei2 plasmid profile found in the us isolates. seq ...201324062549
roles of plasmid-encoded proteins, eseh, esei and escd in invasion, replication and virulence of edwardsiella ictaluri.native plasmids pei1 and pei2 were detected in edwardsiella ictaluri hsn-1 isolated from diseased yellow catfish (pelteobagrus fulvidraco). eseh encoded by pei1 and other two proteins, esei and escd, encoded by pei2, were found with homology to type iii secretion system (t3ss) proteins. to investigate their roles in pathogenesis, the native plasmids were cured based on plasmid incompatibility by introducing a kan positive and sacb negative selection marker into gene spacer of the native plasmids ...201323850444
transferable green fluorescence-tagged pei2 in edwardsiella ictaluri and preliminary investigation of its effects on virulence.edwardsiella ictaluri is the etiologic agent of enteric septicemia of catfish, which causes substantial losses in catfish aquaculture. to determine pathogen-host interactions, previous studies have used the green fluorescence protein (gfp) gene. here, the pei2 plasmid of e. ictaluri isolate i49 was tagged using a tn10-gfp-kan cassette to create the green fluorescence-expressing derivative i49-gfp. the tn10-gfp-kan insertion site was mapped by plasmid sequencing to 663 bp upstream of open reading ...201323836772
tricarboxylic acid cycle and one-carbon metabolism pathways are important in edwardsiella ictaluri virulence.edwardsiella ictaluri is a gram-negative facultative intracellular pathogen causing enteric septicemia of channel catfish (esc). the disease causes considerable economic losses in the commercial catfish industry in the united states. although antibiotics are used as feed additive, vaccination is a better alternative for prevention of the disease. here we report the development and characterization of novel live attenuated e. ictaluri mutants. to accomplish this, several tricarboxylic acid cycle ...201323762452
bacterial distribution and tissue targets following experimental edwardsiella ictaluri infection in nile tilapia oreochromis niloticus.edwardsiella ictaluri, a gram-negative enteric bacterium, is the known etiological agent of enteric septicemia of catfish. in the last few years, different strains have been implicated as the causative agent of mortality events in cultured fish, including nile tilapia oreochromis niloticus l. due to the emergent nature of edwardsiellosis in non-ictalurid fish, little is known about the dynamics of e. ictaluri infection in tilapia. the purpose of this study was to gain a better understanding of t ...201323709463
pathogen recognition receptors in channel catfish: iii phylogeny and expression analysis of toll-like receptors.toll-like receptors (tlrs) were the earliest characterized and the most extensively studied pathogen recognition receptors (prrs). the majority of tetrapod tlr orthologs have been found in teleost fish. in addition, a group of "fish-specific" tlrs have been identified. in catfish, a number of tlr-related sequences have been reported, but systematic phylogenetic analyses have not been conducted. in this study, we conducted phylogenetic and comparative analysis of 20 catfish tlr genes against thei ...201323396097
in vivo effects of escherichia coli lipopolysaccharide on regulation of immune response and protein expression in striped catfish (pangasianodon hypophthalmus).lipolysaccharide (lps), a component of outer membrane protein of gram-negative bacteria, reportedly stimulates fish immune system. however, mechanisms driving this immunomodulatory effect are yet unknown. to determine effects of escherichia coli lipopolysaccharide on regulation of immune response and protein expression of striped catfish (pangasianodon hypophthalmus), juvenile fish (20-25 g) were injected with 3, 15 or 45 mg e.coli lps/kg and challenged with edwardsiella ictaluri. plasma cortiso ...201323207480
construction and evaluation of an edwardsiella ictaluri fhuc mutant.edwardsiella ictaluri is a gram-negative facultative intracellular pathogen causing enteric septicemia in channel catfish. iron is an essential micronutrient needed for bacterial virulence, and to acquire iron, many gram-negative bacteria secrete ferric iron chelating siderophores. the ferric hydroxamate uptake (fhu) system consists of four genes (fhuc, fhud, fhub, and fhua), and is involved in the uptake of hydroxamate type siderophores across bacterial membranes. however, the fhu system and it ...201323201245
changes of serum myeloperoxidase and nitric oxide in the early stage of edwardsiella ictaluri infection in channel catfish, ictalurus punctatus (rafinesque). 201323126429
use of bioluminescence mutant screening for identification of edwardsiella ictaluri genes involved in channel catfish (ictalurus punctatus) skin colonization.initial invasion of the host is the first and vital part of any infection process. we have demonstrated that edwardsiella ictaluri is capable of colonizing and penetrating catfish skin. therefore, a mutant library was constructed by random insertion of the mar2xt7 transposon into the chromosome of e. ictaluri harboring the bioluminescence plasmid pakgfplux1. this library was then screened through a series of three consecutive challenges for mutants showing a decreased ability to colonize the cat ...201323092811
mortality and pathology of hybrid catfish, clarias macrocephalus (günther) × clarias gariepinus (burchell), associated with edwardsiella ictaluri infection in southern thailand.enteric septicaemia of catfish (esc) caused by edwardsiella ictaluri is becoming an increasing problem in aquaculture and has been reported worldwide in a variety of fish species. this study reports esc in hybrid catfish, clarias macrocephalus (günther) × clarias gariepinus (burchell), cultured in southern thailand. the bacteria were identified as e. ictaluri by conventional and rapid identification systems, as well as by genetic and phylogenetic characterization. analysis of 16s rrna indicated ...201423763374
can immunostimulants efficiently replace antibiotic in striped catfish (pangasianodon hypophthalmus) against bacterial infection by edwardsiella ictaluri?the present study was performed to determine the efficacy of lipopolysaccharide (lps) and levamisole on immune response and disease resistance in striped catfish and to compare their respective efficiency with the one of an antibiotic treatment after infection of fish by the bacteria edwardsiella ictaluri. fish were divided into 3 groups and each group was injected with lps (3 mg/kg fish), levamisole (5 mg/kg fish) or phosphate buffer saline as control. at day 21st post immunostimulant injection ...201425120215
comparative susceptibility of channel catfish, blue catfish, and their hybrid cross to experimental challenge with bolbophorus damnificus (digenea: bolbophoridae) cercariae.the digenetic trematode bolbophorus damnificus has been implicated in significant losses in catfish aquaculture since the late 1990s. the complex life cycle sequentially involves the american white pelican pelecanus erythrorhynchos, the marsh rams horn snail planorbella trivolvis, and channel catfish ictalurus punctatus. research supports anecdotal reports from the industry, suggesting that the hybrid of channel catfish×blue catfish i. furcatus is less susceptible to disease agents that have bee ...201424895863
risk factors associated with enteric septicemia of catfish on mississippi commercial catfish farms.a gram-negative bacterium, edwardsiella ictaluri, is the cause of enteric septicemia of catfish (esc), which is one of the most prevalent bacterial diseases in farm-raised catfish. the objective of this study was to identify risk factors associated with esc mortalities and are reported by farm personnel. to identify risk factors a catfish management database was developed. the odds ratios (or) of the final multivariable logistic regression model were: (1) volume of the pond (or, 0.56), (2) inter ...201424895861
tissue persistence and vaccine efficacy of tricarboxylic acid cycle and one-carbon metabolism mutant strains of edwardsiella ictaluri.edwardsiella ictaluri causes enteric septicemia in fish. recently, we reported construction of e. ictaluri mutants with single and double gene deletions in tricarboxylic acid cycle (tca) and one-carbon (c-1) metabolism. here, we report the tissue persistence, virulence, and vaccine efficacy of tca cycle (eiδsdhc, eiδfrda, and eiδmdh), c-1 metabolism (eiδgcvp and eiδglya), and combination mutants (eiδfrdaδsdhc, eiδgcvpδsdhc, eiδmdhδsdhc, and eiδgcvpδglya) in channel catfish. the tissue persistenc ...201424837777
pathogen recognition receptors in channel catfish: iv. identification, phylogeny and expression analysis of peptidoglycan recognition proteins.peptidoglycan recognition proteins (pgrps) can recognize bacterial cell wall (peptidoglycan) and activate innate immune system. in addition to its function as pathogen recognition receptors (prrs), pgrps are also involved in directly killing bacteria, and regulating multiple signaling pathways. recently, we have reported catfish prrs including nucleotide-binding domain, leucine-rich repeat containing receptors (nlrs), retinoic acid inducible gene i (rig-i) like receptors (rlrs), and toll-like re ...201424814805
development of a bacterial challenge test for gnotobiotic nile tilapia oreochromis niloticus larvae.gastrointestinal microbiota have an important impact on fish health and disease, stimulating interest in a better understanding of how these gastrointestinal microbial communities are composed and consequently affect host fitness. in this respect, probiotic microorganisms have been extensively used in recent aquaculture production. to study the use of probiotics in the treatment of infectious diseases, the establishment of a method of experimental infection to obtain consistent results for morta ...201424781794
complete genome sequence of the edwardsiella ictaluri-specific bacteriophage pei21, isolated from river water in japan.we present the complete genome sequence for a novel edwardsiella ictaluri-specific bacteriophage, pei21, isolated from river water in japan. an initial comparative genome analysis revealed that the phage was closely related to the previously reported edwardsiella tarda phage msw-3 isolated from a red sea bream farm in japan.201424699953
effects of ammonia stress, dietary linseed oil and edwardsiella ictaluri challenge on juvenile darkbarbel catfish pelteobagrus vachelli.a two-stage study was carried out to test the response of juvenile darkbarbel catfish pelteobagrus vachelli to ammonia stress, dietary lipid and bacterial challenge. at stage 1, the catfish (0.99 ± 0.01 g) fed a commercial diet were exposed to 0.01 and 5.70 mg l(-1) total ammonia nitrogen in nine replicates for 14 days. at stage 2, all fish previously exposed to either low or high ammonia were separately transferred into low ammonia (<0.01 mg l(-1)), and divided into three feeding groups. fish w ...201424657724
characterization and mucosal responses of interleukin 17 family ligand and receptor genes in channel catfish ictalurus punctatus.interleukin (il) 17 family cytokines are important mediators of mucosal immune responses, tightly regulated by signals from the complex milieu of pathogenic and commensal microbes, epithelial cells and innate and adaptive leukocytes found at tissue barriers. in mammals, il17 ligand expression has been linked not only to protective immunity but also excessive tissue inflammation and damage in the gut and lungs. to better understand the scope and action of the il17 family in channel catfish ictalu ...201424602926
expression of nitric oxide synthase (nos) genes in channel catfish is highly regulated and time dependent after bacterial challenges.nitric oxide is well known for its roles in immune responses. as such, its synthesizing enzymes have been extensively studied from various species including some teleost fish species. however, the nos genes have not been characterized in channel catfish (ictalurus punctatus). in this study, we identified and characterized three nos genes including one nos1 and two nos2 genes in channel catfish. comparing with the nos genes from other fish species, the catfish nos genes are highly conserved in th ...201424560653
effect of multiple mutations in tricarboxylic acid cycle and one-carbon metabolism pathways on edwardsiella ictaluri pathogenesis.edwardsiella ictaluri is a gram-negative facultative intracellular pathogen causing enteric septicemia of catfish (esc). we have shown recently that tricarboxylic acid cycle (tca) and one-carbon (c1) metabolism are involved in e. ictaluri pathogenesis. however, the effect of multiple mutations in these pathways is unknown. here, we report four novel e. ictaluri mutants carrying double gene mutations in tca cycle (eiδmdhδsdhc, eiδfrdaδsdhc), c1 metabolism (eiδglyaδgcvp), and both tca and c1 metab ...201424418045
the teleost acute-phase inflammatory response and caspase activation by a novel alarmin-like ligand.this study tested the hypothesis that ncamp-1 has alarmin-like properties and activates the caspase-1-binding site in cells of the teleost bone marrow (equivalent). in mammals, alarmins have been studied extensively; however, in teleosts, little is known about their identity and functions. similar to alarmins, ncamp-1 has a broad spectrum of bacteriolytic activity. ncamp-1 is constitutively present in cf serum, and levels were increased following infection with edwardsiella ictaluri binding to a ...201424399841
vaccine efficacy of glyceraldehyde-3-phosphate dehydrogenase (gapdh) from edwardsiella ictaluri against e. tarda in tilapia.glyceraldehyde-3-phosphate dehydrogenase (gapdh), derived from the outer-membrane protein (omp) fraction, has been used as a potential candidate for vaccine development. the gene-encoding 37 kda gapdh outer membrane protein (omp) from edwardsiella ictaluri was amplified using polymerase chain reaction (pcr) and was cloned and expressed in escherichia coli bl21 (de3). sodium dodecyl sulfate polyacrylamide gel electrophoresis (sds-page), western blotting, and nucleotide and amino acid sequencing w ...201425742975
phenotypic traits, virulence-associated gene profile and genetic relatedness of edwardsiella tarda isolates from japanese eel anguilla japonica in korea.edwardsiella tarda is the predominant bacterium in farm-cultured eel in korea. here, we evaluated the heterogeneity of 37 e. tarda isolates derived from japanese eel with various origins (olive flounder, common carp and ornamental fish) between 2003 and 2010. regardless of origins, the biochemical characteristics of e. tarda isolates were homogenous except hydrogen sulfide production, citrate utilization and mannitol fermentation. based on the phylogenetic analysis of 16s rrna, e. tarda isolates ...201424117973
inflammatory effects of edwardsiella ictaluri lipopolysaccharide modifications in catfish gut.bacterial lipopolysaccharides (lps) are structural components of the outer membranes of gram-negative bacteria and also are potent inducers of inflammation in mammals. higher vertebrates are extremely sensitive to lps, but lower vertebrates, like fish, are resistant to their systemic toxic effects. however, the effects of lps on the fish intestinal mucosa remain unknown. edwardsiella ictaluri is a primitive member of the enterobacteriaceae family that causes enteric septicemia in channel catfish ...201424866806
Refresh
firstprev
123
nextlast
Displaying items 101 - 200 of 263