\u3ci\u3eFundulus\u3c/i\u3e as the premier teleost model in environmental biology: Opportunities for new insights using genomics

A strong foundation of basic and applied research documents that the estuarine fish Fundulus heteroclitus and related species are unique laboratory and field models for understanding how individuals and populations interact with their environment. In this paper we summarize an extensive body of work examining the adaptive responses of Fundulus species to environmental conditions, and describe how this research has contributed importantly to our understanding of physiology, gene regulation, toxicology, and ecological and evolutionary genetics of teleosts and other vertebrates. These explorations have reached a critical juncture at which advancement is hindered by the lack of genomic resources for these species. We suggest that a more complete genomics toolbox for F. heteroclitus and related species will permit researchers to exploit the power of this model organism to rapidly advance our understanding of fundamental biological and pathological mechanisms among vertebrates, as well as ecological strategies and evolutionary processes common to all living organisms

Fundulus as the premier teleost model in environmental biology : opportunities for new insights using genomics

Author Posting. © Elsevier B.V., 2007. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Comparative Biochemistry and Physiology Part D: Genomics and Proteomics 2 (2007): 257-286, doi:10.1016/j.cbd.2007.09.001.A strong foundation of basic and applied research documents that the estuarine fish Fundulus heteroclitus and related species are unique laboratory and field models for understanding how individuals and populations interact with their environment. In this paper we summarize an extensive body of work examining the adaptive responses of Fundulus species to environmental conditions, and describe how this research has contributed importantly to our understanding of physiology, gene regulation, toxicology, and ecological and evolutionary genetics of teleosts and other vertebrates. These explorations have reached a critical juncture at which advancement is hindered by the lack of genomic resources for these species. We suggest that a more complete genomics toolbox for F. heteroclitus and related species will permit researchers to exploit the power of this model organism to rapidly advance our understanding of fundamental biological and pathological mechanisms among vertebrates, as well as ecological strategies and evolutionary processes common to all living organisms.This material is based on work supported by grants from the National Science Foundation DBI-0420504 (LJB), OCE 0308777 (DLC, RNW, BBR), BES-0553523 (AW), IBN 0236494 (BBR), IOB-0519579 (DHE), IOB-0543860 (DWT), FSML-0533189 (SC); National Institute of Health NIEHS P42-ES007381(GVC, MEH), P42-ES10356 (RTD), ES011588 (MFO); and NCRR P20 RR-016463 (DWT); Natural Sciences and Engineering Research Council of Canada Discovery (DLM, TDS, WSM) and Collaborative Research and Development Programs (DLM); NOAA/National Sea Grant NA86RG0052 (LJB), NA16RG2273 (SIK, MEH,GVC, JJS); Environmental Protection Agency U91620701 (WSB), R82902201(SC) and EPA’s Office of Research and Development (DEN)

Effect of Sargassum oligocystum Hot-Water Extract on Innate Immune Response and Survival of Summer Flounder Paralichthys dentatus to Vibrio harveyi Challenge

The present study evaluated the effects of hot-water extract of a brown seaweed Sargassum oligocystum on the non-specific immune response and survival of summer flounder Paralichthys dentatus, to Vibrio harveyi bacterial challenge. Fish were either immersed in 100 or 500 mg/L or injected with 0.1 or 0.5 mg per fish of the hot-water extract. The innate humoral (lysozyme, plasma protein, bactericidal activity), cellular (respiratory burst, hematocrit), and disease resistance to Vibrio harveyi infection were determined. Results showed that all the experimental treatments either by injection or immersion, significantly enhanced respiratory burst activity and hematocrit values of the fish. In the experiment, all the treatments of hot-water extract significantly affected the lysozyme, plasma protein, and bactericidal activity of the experimental fish from days 1 to 5 after delivery. Following the bacterial challenge mortality decreased significantly in all treated groups. In summer flounder, administration of hot-water extract of S. oligocystum either by injection or immersion was found to be an immunoprophylactic for finfish aquaculture. The efficacy of using hot-water extract as a feed supplement or feed additive needs further examination

Role of nitric oxide in the defenses of Crassostrea virginica to experimental infection with the protozoan parasite Perkinsus marinus

We investigated the role of nitric oxide (NO) in the responses of the Eastern oyster, Crassostrea virginica, to the protozoan parasite Perkinsus marinus, causative agent of Dermo disease. P. marinus induced a slight but significant increase in NO production by oyster hemocytes in vitro, comparable to the increase induced by the immune stimulants phorbol myristrate acetate (PMA) and lipopolysaccharide (LPS). P. marinus also activated the NO response in oysters in vivo, as shown by induction of a protein reacting with a universal NO synthase (NOS) antibody in hemocytes and the presence of high levels of nitrite in plasma. Treatment of experimentally infected oysters with the NOS inhibitor, Nω-nitro-l-arginine methyl ester (l-NAME) resulted in a transient decrease in NO levels in oyster plasma and a significant increase in the number of parasites at early time points after infection. The NO donor, S-nitroso-N-acetyl-penicillamine (SNAP) caused a significant inhibition in the proliferation of P. marinus cultured cells after 24 h of incubation. These results indicate that NO has a role in decreasing parasite loads at early time points after infection. © 2007 Elsevier Ltd. All rights reserved

Effect of sargassum oligocystum hot-water extract on innate immune response and survival of summer flounder paralichthys dentatus to Vibrio harveyi challenge

The present study evaluated the effects of hot-water extract of a brown seaweed Sargassum oligocystum on the non-specific immune response and survival of summer flounder Paralichthys dentatus, to Vibrio harveyi bacterial challenge. Fish were either immersed in 100 or 500 mg/L or injected with 0.1 or 0.5 mg per fish of the hot-water extract. The innate humoral (lysozyme, plasma protein, bactericidal activity), cellular (respiratory burst, hematocrit), and disease resistance to Vibrio harveyi infection were determined. Results showed that all the experimental treatments either by injection or immersion, significantly enhanced respiratory burst activity and hematocrit values of the fish. In the experiment, all the treatments of hot-water extract significantly affected the lysozyme, plasma protein, and bactericidal activity of the experimental fish from days 1 to 5 after delivery. Following the bacterial challenge mortality decreased significantly in all treated groups. In summer flounder, administration of hot-water extract of S. oligocystum either by injection or immersion was found to be an immunoprophylactic for finfish aquaculture. The efficacy of using hot-water extract as a feed supplement or feed additive needs further examination

Evaluation of eukaryotic promoters for the construction of DNA vaccines for aquaculture

We evaluated fish promoters as an alternative to viral promoters in the construction of DNA vaccines for aquaculture. A carp β-actin promoter drove expression of the luciferase gene in live fish tissue to levels comparable to the CMVtk promoter. Copyright (C) 1999 Elsevier Science B.V

The role of histones in the immune responses of aquatic invertebrates

Histones are primary components of eukaryotic chromatin and highly abundant in all animal cells. In addition to their important role in chromatin structure and transcriptional regulation, histones contribute to innate immune responses. In several aquatic invertebrate species, as well as in many other invertebrate and vertebrate species, the transcripts for core histones are upregulated in response to immune challenge and exposure to environmental stressors. Histones show antimicrobial activity against bacteria and parasites in vitro and in vivo and have the ability to bind bacterial lipopolysaccharide and other pathogen-associated molecules. Several mechanisms regulating and facilitating the antimicrobial action of histones against pathogens have been described in vertebrate and some invertebrate species, including the production of Extracellular Traps (ETs) and the accumulation of histones in lipid droplets that can be selectively released in response to immune stimuli. Further studies are needed to determine the mechanisms of action of histones in immune responses in aquatic invertebrates and investigate the potential use of histones in the treatment of infectious diseases in aquaculture

Upregulation in response to infection and antibacterial activity of oyster histone H4

Several histones and histone-derived peptides have been shown to have antimicrobial activity and a potential role in innate immune defenses. A histone H4 sequence was identified in a subtractive suppression library containing genes upregulated in American cupped oysters, Crassostrea virginica, in response to challenge with the protozoan parasite Perkinsus marinus. Oyster histone H4 protein levels significantly increased in hemocyte lysates and cell free hemolymph of oysters experimentally challenged with P. marinus. The complete histone H4 coding sequence of C. virginica was cloned into a Saccharomyces cerevisiae yeast expression system and recombinant expression was confirmed using SDS-PAGE analysis and western blot. Delivery of yeast cells expressing recombinant oyster histone H4 into the gut of brine shrimp, Artemia salinas, challenged with a streptomycin resistant strain of Vibrio anguillarum resulted in a significant and dose-dependent decrease in the load of V. anguillarum. Purified recombinant histone H4 showed antimicrobial activity against V. anguillarum and Escherichia coli at micromolar concentrations, but did not affect the viability of P. marinus in culture. These results support the role of histone H4 in the defense of oysters against bacterial infection and validate the use of a novel oyster antimicrobial H4 in a yeast feed-based delivery system for the treatment of bacterial infections in aquaculture applications. © 2010 Elsevier Ltd

Developing tools for the study of molluscan immunity: Thesequencing of the genome of the eastern oyster, Crassostrea virginica

The eastern oyster, Crassostrea virginica, provides important ecological and economical services, making it the target of restoration projects and supporting a significant fishery/aquaculture industry with landings valued at more than $100 million in 2012 in the United States of America. Due to the impact of infectious diseases on wild, restored, and cultured populations, the eastern oyster has been the focus of studies on host-pathogen interactions and immunity, as well as the target of selective breeding efforts for disease resistant oyster lines. Despite these efforts, relatively little is known about the genetic basis ofresistance to diseases or environmental stress, not only in eastern oyster, but also in other molluscan species of commercial interest worldwide. In order to develop tools and resources to assist in the elucidation of the genomic basis of traits of commercial, biological, and ecological interest in oysters, ateam of genome and bioinformatics experts, in collaboration with the oyster research community, is sequencing, assembling, and annotating the first reference genome for the eastern oyster and producing an exhaustive transcriptome from a variety of oyster developmental stages and tissues in response to adiverse set of environmentally-relevant stimuli. These transcriptomes and reference genome for theeastern oyster, added to the already available genome and transcriptomes for the Pacific oyster (Crassostrea gigas) and other bivalve species, will be an essential resource for the discovery of candidate genes and markers associated with traits of commercial, biological, and ecologic importance in bivalve molluscs, including those related to host-pathogen interactions and immunity

Vibrio harveyi and other bacterial pathogens in cultured summer flounder, Paralichthys dentatus

A monitoring program for Vibrio harveyi and other potential bacterial pathogens of summer flounder was conducted at two facilities in the Northeast United States. Bacterial samples were collected from larval and juvenile fish and live-feed, and identified using API 20E biochemical profiles and 16S rDNA sequencing. Histopathological examinations were conducted in order to relate histological changes with the presence of potential bacterial pathogens. V. harveyi, Vibrio ichthyoenteri, and Photobacterium damselae subsp. damselae, three known pathogens of flatfish, were isolated from diseased summer flounder. Although a high proportion of juvenile summer flounder showed microscopic signs of disease, the presence of these potential bacterial pathogens in fish was not associated with large-scale mortalities. An outbreak of flounder infectious necrotizing enteritis with 30% cumulative mortality occurred when juveniles were transported to a new facility. Isolates of V. harveyi from the disease outbreak were genetically different from the isolates from the commercial hatchery. V. harveyi isolates from both facilities were pathogenic to summer flounder by intraperitoneal injection. P. damselae subsp. damselae, V. ichthyoenteri, and Vibrio scophthalmi, also found in fish with gross lesions, were not pathogenic to juvenile summer flounder by intraperitoneal injection. Our research shows that several potential bacterial pathogens are associated with morbidity and mortality in summer flounder larvae and juveniles, especially in situations of stress. Increased knowledge about the environmental conditions that lead to disease, as well as the interactions of V. harveyi with other microbial species, could lead to the development of management strategies in summer flounder farms. © 2006 Elsevier B.V. All rights reserved