Search

Pacific lamprey, Lampetra tridentata, has declined precipitously throughout their range in the Columbia River basin of North America. Tribal Nations and Federal and State agencies are engaged in efforts to restore these fish. Understanding whether Pacific lamprey emit and detect migratory pheromones is particularly important for these restoration efforts. Using behavioural assays, we demonstrated that migratory adult Pacific lamprey are attracted to odors emanating from their larval conspecifics. We then identified putative pheromones released by larval Pacific lamprey. Chemical analysis of the conditioned water from larval lamprey using liquid chromatography--mass spectrometry (LC-MS) revealed that the Pacific lamprey can release petromyzonamine disulfate (PADS), petromyzosterol disulfate (PSDS), and petromyzonol sulfate (PZS). Electro-olfactogram studies further demonstrated that adult Pacific lamprey can smell those bile acid compounds. Our data strongly indicate that the Pacific lamprey employ a chemical communication system mediated by a mixture of bile acids, as evidenced by pheromonal functions of the bile acid compounds in guiding migratory adult sea lamprey to the spawning streams. Comprehensive understanding of the chemical communications involved in lamprey migratory behavior may lead to improved scientific approaches for restoration efforts. La lamproie du Pacifique, Lampetra tridentata, a diminue de facon rapide dans l'ensemble de leur aire de repartition dans le bassin du Columbia en Amerique du Nord. Les agences des nations tribales, des etats et du gouvernement federal se sont engagees dans des efforts pour la restauration de ces poissons. Dans ces efforts de restauration, il est particulierement important de connaitre si les lamproies du Pacifique emettent et detectent des pheromones de migration. A l'aide de tests comportementaux, nous avons demontre que les lamproies du Pacifique migratrices sont attirees par les odeurs emises par les larves de leur propre espece. Nous avons ensuite identifie les hormones putatives emises par les larves des lamproies du Pacifique. L'analyse chimique par chromatographie en phase liquide et spectrometrie de masse (LC-MS) de l'eau conditionnee par les larves de lamproies montre que les lamproies du Pacifique peuvent emettre du bisulfate de petromyzonamine (PADS), du bisulfate de petromyzosterol (PSDS) et du sulfate de petromyzonol (PZS). Des l'electroolfactogrammes demontrent en plus que les lamproies du Pacifique adultes peuvent sentir ces composes d'acides biliaires. Nos donnees indiquent clairement que la lamproie du Pacifique utilise un systeme de communication chimique par l'intermediaire d'un melange d'acides biliaires, comme le demontre la fonction de pheromone exercee par le melange d'acides biliaires pour guider les lamproies marines migratrices vers leurs cours d'eau de fraie. Une comprehension globale des communications chimiques impliquees dans le comportement migrateur des lamproies peut mener a des approches scientifiques ameliorees dans les efforts de restauration. [Traduit par la Redaction], Introduction The Pacific lamprey Lampetra (Entosphenus) tridentata has declined throughout much of its range in the Columbia River basin of North America (Close et al. 2002). Concerns about the declining [...]

We show that reproductively mature male sea lampreys release a bile acid that acts as a potent sex pheromone, inducing preference and searching behavior in ovulated female lampreys. The secreted bile acid 7α,12α,24-trihydroxy-5α-cholan-3-one 24-sulfate was released in much higher amounts relative to known vertebrate steroid pheromones and may be secreted through the gills. Hence, the male of this fish species signals both its reproductive status and location to females by secreting a pheromone that can act over long distances., The sea lamprey, Petromyzon marinus, is an ancestral jawless fish and an invasive parasite of fishes, particularly in the Laurentian Great Lakes of North America. It migrates into streams to [...]

Ocean acidification negatively affects many marine species and is predicted to cause widespread changes to marine ecosystems. Similarly, freshwater ecosystems may potentially be affected by climate-change-related acidification; however, this has received far less attention. Freshwater fish represent 40% of all fishes, and salmon, which rear and spawn in freshwater, are of immense ecosystem, economical and cultural importance. In this study, we investigate the impacts of CO2-induced acidification during the development of pink salmon, in freshwater and following early seawater entry. At this critical and sensitive life stage, we show dose-dependent reductions in growth, yolk-to-tissue conversion and maximal O2 uptake capacity; as well as significant alterations in olfactory responses, anti-predator behaviour and anxiety under projected future increases in CO2 levels. These data indicate that future populations of pink salmon may be at risk without mitigation and highlight the need for further studies on the impact of CO2-induced acidification on freshwater systems. [ABSTRACT FROM AUTHOR]

In echinoderms, the SALMFamide neuropeptides sharing the SxL/FxFamide motif seem widespread throughout the phylum and may be important signalling molecules that mediate various physiological functions. Recent identification of S1 and its analogues, MagS3 and MagS4, along with the S2 analogue, MagS2 from the starfish Marthasterias glacialis, indicated that SALMFamides in the class Asteroidea are more diverse than previously thought. Further, isolation of the neuropeptides from the radial nerve cord and studies on pharmacological actions of the neuropeptides on the cardiac stomach warrant studies on the tissue distributions of these peptides in both the nervous and digestive systems. In the present study, antisera raised against an S1 analogue, KYSALMFamide, and an S2 analogue, KYSGLTFamide, were used to localize the distribution patterns of the S1- and S2-like immunoreactivities (S1-IR/S2-IR) in the nervous and digestive systems of the starfish. In the nervous system, cell bodies in the ectoneural part were immunostained for both S1 and S2 peptides, while in the digestive system, the basi-epithelial plexus and mucosal cell bodies were immunoreactive. These immunocytochemical data support the notion that the SALMFamides may play a neuroendocrine role in mediating feeding behaviour of the starfish. Further studies including identification of peptide binding sites and differential expression pattern of mRNAs encoding the peptides are required to elucidate their physiological functions. [ABSTRACT FROM AUTHOR]

Many environmental pollutants induce expression of the cytochrome P450 (CYP) 1A subfamily of genes. We integrated cellular and molecular biological techniques to examine the effects of beta-naphthoflavone (BNF) exposure in lake trout brain CYP1A distribution and dynamics. Over a 32-day time-course, real time quantitative reverse transcription polymerase chain reaction (Q-RT-PCR) results showed that CYP1A mRNA induction in response to BNF exposure occurred rapidly and continued to rise in the BNF-treated lake trout after 4 h, with a peak at or after 2 days. Messenger RNA levels fell after 4 days, and this trend continued after 16 days of exposure. In situ hybridization indicated that CYP1A mRNA was universally elevated in the brain of BNF-exposed fish and was mainly expressed in the endothelia and occasionally in the glial cells. CYP1A immunoreactivity was induced in the olfactory bulb and valvula cerebelli of BNF-treated fish. Other brain areas showed constitutive CYP1A immunoreactivity in both control and BNF-treated fish. Some BNF-treated fish contained multifocal hemorrhages in the brain tissue, and these fish had overall depressed CYP1A immunoreactivity in the brain. The relationship between transcriptional and translational effects of BNF exposure in the brain of juvenile lake trout is discussed.