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The movement away from mammalian testing of potential toxicants and new chemical entities has primarily led to cell line testing and protein-based assays. However, these assays may not yet be sufficient to properly characterize the toxic potential of a chemical. The zebrafish embryo model is widely recognized as a potential new approach method for chemical testing that may provide a bridge between cell and protein-based assays and mammalian testing. The Zebrafish Embryo Toxicity (ZET) model is increasingly recognized as a valuable toxicity testing platform. The ZET assay focuses on the early stages of embryo development and is considered a more humane model compared to adult zebrafish testing. A complementary model has been developed that exposes larvae to toxicants at a later time point during development where body patterning has already been established. Here we compare the toxicity profiles of 20 compounds for this General and Behavioral Toxicity (GBT) assay to the ZET assay. The results show partially overlapping toxicity profiles along with unique information provided by each assay. It appears from this work that these two assays applied together can strengthen the use of zebrafish embryos/larvae as standard toxicity testing models.

Marine and freshwater microalgae were evaluated for their antioxidant properties and lipid composition. Both lipophilic (L) and hydrophilic (H) oxygen radical absorbance capacity (ORAC) values were measured. Among the tested microalgae, the marine microalga Nannochloropsis granulata showed the highest total ORAC value at 6948 μmol TE (100 g)−1, followed by the freshwater species Neochloris oleoabundans at 4508 μmol TE (100 g)−1 and Scenedesmus obliquus at 4406 μmol TE (100 g)−1 of algal biomass. Freeze-dried algal biomass was also examined for lipid content by the Folch method. Lipid content ranged from 30.9 to 49.3% and linear regression analysis revealed a statistically significant correlation between the lipid content and the ORAC values. Tested microalgae showed moderate and dose-dependent DPPH radical scavenging activity. The total phenol assay shows that marine microalga Tetraselmis chui had the highest phenolic content at 57.5 μmol GAE g−1 and N. oleoabundans had the lowest at 26.6 μmol GAE g−1 of MeOH extract. A statistically significant correlation was detected between DPPH radical scavenging activity and the phenolic content. Fatty acid analysis revealed that polyunsaturated fatty acids constituted > 45% of the total fatty acid content in N. oleoabundans, Phaeodactylum tricornutum, Porphyridium aerugineum, S. obliquus, and Scenedesmus sp. Total carotenoid concentration ranged from 1.1 to 29.5 mg g−1 of dry algal biomass. Lutein, zeaxanthin, and β-carotene are common carotenoids found in most of the algae tested. P. tricornutum contains significant amount of fucoxanthin at 24.3 mg g−1 algal biomass. These carotenoids also contributed to the overall antioxidative activity of microalgae.

The EtOAc soluble fraction of a MeOH/CHCl3 extract of Palmaria palmata showed strong nitric oxide (NO) inhibitory activity against lipopolysaccharide (LPS)-induced NO production in murine RAW264.7 cells. NO inhibition-guided isolation led to identification of three new polar lipids including a sulfoquinovosyl diacylglycerol (SQDG) (2S)-1-O-eicosapentaenoyl-2-O- myristoyl-3-O-(6-sulfo-α-d-quinovopyranosyl)-glycerol (1) and two phosphatidylglycerols, 1-O-eicosapentaenoyl-2-O-trans-3-hexadecenoyl-3-phospho- (1′-glycerol)-glycerol (3) and 1-O-eicosapentaenoyl-2-O-palmitoyl-3- phospho-(1′-glycerol)-glycerol (4) from the EtOAc fraction. Seven known lipids were also isolated including a SQDG (2), a phospholipid (5) and five galactolipids (6-10). Structures of the isolated lipids were elucidated by spectral analyses. The isolated SQDGs, phosphatidylglycerols and phospholipid possessed strong and dose-dependent NO inhibitory activity compared to N G-methyl-l-arginine acetate salt (l-NMMA), a well-known NO inhibitor used as a positive control. Further study suggested that these polar lipids suppressed NO production through down-regulation of inducible nitric oxide synthase (iNOS).

We report genetic differences for resistance to the pathogen Listonella anguillarum within and among one cultured and two wild Canadian populations of Atlantic salmon, Salmo salar, using a common-garden experimental protocol. Following exposure to the causative agent for vibriosis, parr originating from the endangered Stewiacke River population experienced significantly higher mortality than cultured parr, four generations removed from the Saint John River population, and wild parr from Tusket River. Pathogen resistance differed between sexes; males consistently experienced higher survival than females. There was no evidence that maturity influenced pathogen resistance in male parr. The population and sex differences in pathogen resistance documented here have implications for risk assessments of the demographic consequences of interbreeding between wild and farmed Atlantic salmon.

In 1999, disease outbreaks in juvenile Atlantic cod Gadus morhua that showed the classic signs of viral encephalopathy and retinopathy (VER) were reported in Nova Scotia. Brain and retinal tissues from moribund cod showed diffuse degenerative vacuolative encephalopathy and degenerative histiocytic retinitis. The affected brain and retinal tissues were observed to be positive for nodaviral antigens by means of immunohistochemical techniques. We partially characterized a nodavirus-like agent from brain and eye tissues and cell culture using reverse-transcriptase polymerase chain reaction and primer sets originally designed for amplification of white trevally Caranx dentex (also known as striped jack Pseudocaranx dentex) and Atlantic halibut Hippoglossus hippoglossus nervous necrosis virus coat (capsid) proteins. Sequencing of the T2 region of the coat protein revealed high similarities (>85% nucleotide identity) to the coat protein genes of other fish nodavirus strains, especially those of Atlantic...

Chemical investigation of polar lipids from the marine eustigmatophyte microalga Nannochloropsis granulata led to the isolation of six betaine lipid diacylglyceryltrimethylhomoserine (DGTS), namely, (2S)-1,2-bis-O-eicosapentaenoylglyceryl-3-O-4′-(N,N,N-trimethyl)-homoserine (1), (2S)-1-O-eicosapentaenoyl-2-O-arachidonoylglyceryl-3-O-4′-(N,N,N-trimethyl)-homoserine (2), (2S)-1-O-eicosapentaenoyl-2-O-myristoylglyceryl-3-O-4′-(N,N,N-trimethyl)-homoserine (3), (2S)-1-O-eicosapentaenoyl-2-O-palmitoylglyceryl-3-O-4′-(N,N,N-trimethyl)-homoserine (4), (2S)-1-O-eicosapentaenoyl-2-O-palmitoleoylglyceryl-3-O-4′-(N,N,N-trimethyl)-homoserine (5), and (2S)-1-O-eicosapentaenoyl-2-O-linoleoylglyceryl-3-O-4′-(N,N,N-trimethyl)-homoserine (6). Structures of the isolated DGTSs were elucidated based on both spectroscopic technique and degradation methods. This is the first report of isolation of 1 in pure state, and 2–6 are all new compounds. The isolated betaine lipids showed dose-dependent nitric oxide (NO) inhibitory activity against lipopolysaccharide-induced nitric oxide production in RAW264.7 macrophage cells. Further study suggested that these betaine lipids (1–6) inhibit NO production in RAW264.7 macrophage cells through downregulation of inducible nitric oxide synthase expression, indicating the possible use as an anti-inflammatory agent. This is the first report of DGTS with anti-inflammatory activity.

Moritella viscosa is the causative agent of winter ulcer disease in salmonids reared in North-Atlantic countries. In this study the effects of selected M. viscosa antigens on cytotoxicity and pro-inflammatory gene expression in an Atlantic salmon (Salmo salar Linnaeus) macrophage-like cell line (SHK-1) were examined. SHK-1 cells were stimulated with live and heat-killed bacterial cells, extracellular products (ECP) and an extracellular vibriolysin, termed MvP1. Following incubation, cytotoxicity and expression levels of interleukin-1 beta (IL-1 beta) and interleukin-8 (IL-8) were examined at different time points. Both live M. viscosa cells and ECP were cytotoxic, but neither heat-killed cells, nor the MvP1 peptidase caused cell death. Expression levels of both IL-1 beta and IL-8 increased significantly after stimulation with live cells, but heat-killed cells only caused increased IL-8 expression. ECP did not affect IL-1 beta expression, but did stimulate IL-8 expression. The isolated MvP1 peptidase stimulated both IL-1 beta and IL-8 expression at the highest concentration tested. This study reveals a difference in the induction of pro-inflammatory gene expression in salmon SHK-1 cells between live and heat-killed M. viscosa cells, and also that an unknown secreted factor is the main stimulant of IL-beta and IL-8 expression.