P. A. Shoemaker results 28
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Efficacy of an Inactivated Bacterin Vaccine Against Emerging Streptococcus dysgalactiae in Channel Catfish ( Ictalurus punctatus )NARA Subscribed
Lancefield Group C Streptococcus dysgalactiae recently emerged as a catfish pathogen in the US. Reports from hatcheries suggest S. dysgalactiae causes substantial broodfish loss. We aimed to develop a challenge model and evaluate vaccine efficacy against S. dysgalactiae in juvenile channel catfish ( Ictalurus punctatus ). Three S. dysgalactiae (14–1, 14–24 and 14–25) isolates were tested for virulence. Intracoelomic (IC) injec...
Streptococcus dysgalactiae From Farm‐Raised Channel Catfish in Mississippi, USA, With Notes on Fish‐Associated Group C S. dysgalactiaeNARA Subscribed
Lancefield serological group C Streptococcus dysgalactiae (GCSD) is an emerging cause of fish disease worldwide, largely associated with mariculture in Asia. In the United States (US), GCSD had been a pathogen of minimal concern for fish, but recent cases indicate a putative emergence in wild and cultured freshwater fish populations in the Americas. The current study discusses three novel cases of GCSD‐associated streptococcos...
Spatial rarity is often used to predict extinction risk, but rarity can also occur temporally. Perhaps more relevant in the context of global change is whether a species is core to a community (persistent) or transient (intermittently present), with transient species often susceptible to human activities that reduce niche space. Using 5–12 yr of data on 1,447 plant species from 49 grasslands on five continents, we show that lo...
Streptococcus iniae is a significant pathogen impacting aquaculture production worldwide. The objectives of this study were to determine whether a developed modified S. iniae (ARS‐98‐60) bacterin vaccine is efficacious in Nile tilapia, Oreochromis niloticus (L.), against challenge with heterologous isolates from diverse geographical locations and to evaluate protein and antigenic variability among the isolates tested. Two grou...
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...
Lactococcus garvieae infection in cultured Nile tilapia, Oreochromis niloticus (L.), and pintado, Pseudoplathystoma corruscans (Spix & Agassiz), from Brazil is reported. The commercial bacterial identification system, Biolog Microlog ® , confirmed the identity of L. garvieae . Infectivity trials conducted in Nile tilapia using Brazilian Nile tilapia L. garvieae isolates resulted in a median lethal dose‐50 of 1.4 × 10 5 colony‐...
The chemoattractant capabilities of Edwardsiella tarda extracellular products (ECP) were investigated from two isolates, the virulent FL6‐60 parent and less virulent RET‐04 mutant. Chemotaxis and chemokinesis were assayed in vitro using blind well chambers with peritoneal macrophages obtained from Nile tilapia, Oreochromis niloticus , 5 days following squalene injection. Non‐purified ECP derived from both isolates stimulated p...
Evaluation of the link between gyrodactylosis and streptococcosis of Nile tilapia, Oreochromis niloticus (L.)NARA Subscribed
Streptococcus iniae and Gyrodactylus niloticus are two common pathogens of cultured Nile tilapia, Oreochromis niloticus . We studied concurrent infection of tilapia by G. niloticus and S. iniae and evaluated whether parasitism in tilapia with Gyrodactylus increased susceptibility and mortality following immersion infection with S. iniae . Results showed that death mainly occurred in fish with G. niloticus and challenged with S...
Comparison of lipopolysaccharide and protein profiles between Flavobacterium columnare strains from different genomovarsNARA Subscribed
Lipopolysaccharide (LPS) and total protein profiles from four Flavobacterium columnare isolates were compar. These strains belonged to genetically different groups and/or presented distinct virulence properties. Flavobacterium columnare isolates ALG‐00‐530 and ARS‐1 are highly virulent strains that belong to different genomovars while F. columnare FC‐RR is an attenuated mutant used as a live vaccine against F. columnare . Stra...
Apoptosis in Ichthyophthirius multifiliis is associated with expression of the Fas receptor of therontsNARA Subscribed
The expression of type I membrane Fas receptors on the surface of Ichthyophthirius multifiliis (Ich) theronts and the possible association between Fas expression and theront apoptosis induced by the immune antibody was examined. Fas receptors were detected on the theront surface using fluorescein isothiocyanate‐conjugated mouse monoclonal antibody against Fas. Fas‐positive theronts significantly increased with time during in v...
Streptococcus agalactiae is a major bacterial pathogen that is the cause of serious economic losses in many species of freshwater, marine and estuarine fish worldwide. A highly efficacious S. agalactiae vaccine was developed using extracellular products (ECP) and formalin‐killed whole cells of S. agalactiae . The vaccine efficacy following storage of S. agalactiae ECP and formalin‐killed S. agalactiae cells at 4 °C for 1 year...
This study explored the existence of apoptosis (programmed cell death) in Ichthyophthirius multifiliis Fouquet (Ich) theronts and determined the effect of cutaneous antibodies in skin culture fluid from fish immune to Ich on theront apoptosis. Apoptosis was detected in theronts and was clearly distinguished by fluorescent microscopy after staining with acridine orange and propidium iodide. The apoptotic theronts showed charact...
Flavobacterium columnare is an important pathogen of freshwater fish, implicated in skin and gill disease, often causing high mortality. An outbreak of skin disease in fingerling and adult Nile tilapia, Oreochromis niloticus (L.), cultivated in a recirculation system, was investigated. Four strains were isolated and characterized by biochemical reactions, enzyme production, fatty acid profile and analysis of the 16S‐23S rDNA i...
Withholding feed has been suggested as a strategy to manage infectious disease of channel catfish, Ictalurus punctatus (Rafinesque). In a previous study, we demonstrated that deprivation of feed for as little as 7 days reduced innate resistance of catfish to Flavobacterium columnare . This study was conducted to evaluate the effect of feeding regimens [no feeding (NF), fed once every other day to satiation (FEOD) and fed once...
The biological properties of Edwardsiella ictaluri RE‐33 rifampicin‐mutant and its parent strain EILO were analysed. RE‐33 is an avirulent isolate used as a modified live vaccine against enteric septicaemia of catfish. Electrophoretic analysis of lipopolysaccharide (LPS) patterns showed high homology between both isolates. Further characterization of LPS by immunoblotting revealed the main differences in LPS composition. The R...
Streptococcus agalactiae was isolated from cultured gilthead seabream, Sparus auratus L., and diseased wild Klunzinger's mullet, Liza klunzingeri (Day), in Kuwait Bay, Arabian Gulf. Isolates were catalase negative, β‐haemolytic, Gram‐positive cocci and serogroup B. Experimental infectivity trials with mullet and seabream brain isolates in Nile tilapia, Oreochromis niloticus L., caused 100 and 90% mortality, respectively, withi...
Passive immunization of tilapia, Oreochromis niloticus (L.), with anti‐ Streptococcus iniae whole seraNARA Subscribed
Passive immunization of tilapia, Oreochromis niloticus, was conducted to determine whether anti‐ Streptococcus iniae whole sera (ASI), heat inactivated anti‐ S . iniae whole sera (HIASI) and normal whole sera (NWS) were protective when intraperitoneally (i.p.) injected into tilapia. The ASI was produced in tilapia actively immunized (challenged) with virulent S. iniae by i.p. injection. An antibody response against S. iniae wa...