Jonathan Mark Wilson

Wilfrid Laurier University | WLU · Department of Biology

Anatomically, the digestive system of oxudercinae lacks a distinct stomach, and that is why this group of fish is classified as stomachless. Since the environment, dietary requirements, and eating habits strongly influence the anatomy of the fish's digestive system, mudskippers (Periophthalmus waltoni) appear to have a stomach due to their carnivor...

Total suspended solids (TSS) are a major contributor of anthropogenic impacts to aquatic systems. TSS exposure have been shown to affect the function of gills, but the mode of action is unclear. Zebrafish (Danio rerio) is emerging as an excellent model for mechanistic toxicology, and as there are no baseline studies on TSS effects in zebrafish gill...

Aim To determine whether the crustacean Rh1 protein functions as a dual CO 2 /ammonia transporter and investigate its role in branchial ammonia excretion and acid–base regulation. Methods Sequence analysis of decapod Rh1 proteins was used to determine the conservation of amino acid residues putatively involved in ammonia transport and CO 2 binding...

Sea lamprey (Petromyzon marinus) control in the Laurentian Great Lakes of North America makes use of two pesticides: 3-trifluoromethyl-4-nitrophenol (TFM) and niclosamide, which are often co-applied. Sea lamprey appear to be vulnerable to these agents resulting from a lack of detoxification responses with evidence suggesting that lampricide mixture...

The striped eel catfish, Plotosus lineatus was first described by Thunberg in 1787 from the Indo-Pacific region in the East Indian Ocean. Since then, the species has been recorded in various marine and brackish habitats in Japan, southern Korea, the Ogasawara Islands, Australia, Lord Howe Island, Palau and Yap in Micronesia, East Africa to Samoa, M...

Sea lamprey ( Petromyzon marinus ) control in the Laurentian Great Lakes of North America makes use of two pesticides: 3-trifluoromethyl-4-nitrophenol (TFM) and niclosamide, which are often co-applied. Sea lamprey appear to be vulnerable to these agents resulting from a lack of detoxification responses with evidence suggesting that lampricide mixtu...

Sea lamprey (Petromyzon marinus) control in the Laurentian Great Lakes of North America often relies on the application of 3-trifluoromethyl-4-nitrophenol (TFM) and niclosamide mixtures to kill larval sea lamprey. Selectivity of TFM against lampreys appears to be due to differential detoxification ability in these jawless fishes compared to bony fi...

Sea lamprey (Petromyzon marinus) control in the Laurentian Great Lakes of North America often relies on the application of 3-trifluoromethyl-4-nitrophenol (TFM) and niclosamide mixtures to kill larval sea lamprey. Selectivity of TFM against lampreys appears to be due to differential detoxification ability in these jawless fishes compared to bony fi...

An acid-secreting stomach provides many selective advantages to fish and other vertebrates; however, phenotypic stomach loss has occurred independently multiple times and is linked to loss of expression of both the gastric proton pump and the protease pepsin. Reasons underpinning stomach loss remain uncertain. Understanding the importance of gastri...

Phenotypic divergence is a hallmark of adaptive radiation. One example involves differentiation in physiological traits involved in ion regulation among species with contrasting life-styles and living in distinct environments. Differentiation in ion regulation and its ecological implications among populations within species are, however, less well...

Pesticides are critical for invasive species management but often have negative effects on nontarget native biota. Tolerance to pesticides should have an evolutionary basis, but this is poorly understood. Invasive sea lamprey (Petromyzon marinus) populations in North America have been controlled with a pesticide lethal to them at lower concentratio...

Stomach loss has occurred independently multiple times during gnathostome evolution with notable frequency within the Teleostei. Significantly, this loss of acid-peptic digestion has been found to correlate with the secondary genomic loss of the gastric proton pump subunits (atp4a, atp4b) and pepsinogens/pepsins (pga, pgc). Gastric glands produce g...

The gills are the primary site of exchange in fishes. However, during early life-stages or in amphibious fishes, ionoregulation and gas-exchange may be primarily cutaneous. Given the similarities between larval and amphibious fishes, we hypothesized that cutaneous larval traits are continuously expressed in amphibious fishes across all life-stages...

Intertidal crustaceans like Carcinus maenas shift between an osmoconforming and osmoregulating state when inhabiting full-strength seawater and dilute environments, respectively. While the bodily fluids and environment of marine osmoconformers are approximately isosmotic, osmoregulating crabs inhabiting dilute environments maintain their bodily flu...

Little is known about nitrogenous waste (N waste) handling and excretion (JN waste) during the complex life cycle of the sea lamprey (Petromyzon marinus), an extant jawless fish that undergoes a complete metamorphosis from a filter-feeding larva (ammocoete) into a parasitic juvenile that feeds on the blood of larger, jawed fishes. Here, we investig...

Puffer and porcupine fishes (families Diodontidae and Tetraodontidae, order Tetradontiformes) are known for their extraordinary ability to triple their body size by swallowing and retaining large amounts of seawater in their accommodating stomachs. This inflation mechanism provides a defence to predation; however, it is associated with the secondar...

Caspian roach, Rutilus caspicus must have adaptive mechanisms to control internal homeostasis over a broad range of ambient various such as the heat shock (HS) and salinity changes. This experiment was carried out in two stages. In first stage, thirty juveniles fish (3.2 ± 0.34 g) transferred to 20 L circular tanks, containing three different salin...

Cortisol is a major osmoregulatory hormone in fishes. Cortisol acts upon the gills, the primary site of ionoregulation, through modifications to specialized ion-transporting cells called ionocytes. We tested the hypothesis that cortisol also acts as a major regulator of skin ionocyte remodelling in the amphibious mangrove rivulus ( Kryptolebias mar...

Pesticides are critical for invasive species management, but often have negative effects on non-target native biota. Tolerance to pesticides should have an evolutionary basis, but this is poorly understood. Invasive sea lamprey (Petromyzon marinus) populations in North America have been controlled with a pesticide lethal to them at lower concentrat...

Lamprey are living representatives of the basal vertebrate agnathan lineage. Many lamprey species are anadromous with a complex life cycle that includes metamorphosis from a freshwater (FW) benthic filter-feeding larva into a parasitic juvenile which migrates to seawater (SW) or (in landlocked populations) large bodies of FW. After a juvenile/adult...

Global warming is having a significant impact around the world, modifying environmental conditions in many areas, including in zones that have been thermally stable for thousands of years, such as Antarctica. Stenothermal sedentary intertidal fish species may suffer due to warming, notably if this causes water freshening from increased freshwater i...

Teleost fish have a remarkable capacity to maintain ion homeostasis against diffusion gradients in hypo-ionic freshwater. In adult teleosts the gills are the primary site for ion uptake; however, in larvae, the gills are underdeveloped, and as ion-regulation is primarily cutaneous, branchial mechanisms of plasticity are not yet available. In larval...

The present study investigates the response of the hormone arginine vasotocin (AVT), the non-mammalian antidiuretic hormone, to the acclimation of fish to high hydrostatic pressure (5.1 MPa). Two fish species with different osmoregulatory strategies, the lesser spotted dogfish Scyliorhinus canicula , a marine osmoconforming chondrichthyan species a...

Sea lamprey (Petromyzon marinus) begin life as filter-feeding larvae (ammocoetes) before undergoing a complex metamorphosis into parasitic juveniles, which migrate to the sea where they feed on the blood of large-bodied fishes. The greater protein intake during this phase results in marked increases in the production of nitrogenous wastes (N-waste)...

Potassium regulation is essential for the proper functioning of excitable tissues in vertebrates. The H+/ K+-ATPase (HKA), which is comprised of the HKα1 (gene: atp4a) and HKβ (gene: atp4b) subunits, has an established role in potassium and acid-base regulation in mammals and is well known for its role in gastric acidification. However, the role of...

The Atlantic mackerel, Scomber scombrus, is an economically important and widely distributed fish species in the North Atlantic, currently considered to comprise two stocks: the North-West Atlantic (NWA) and the North-East Atlantic (NEA). Each stock is composed of different spawning components which involve temporal and spatial movements driven by...

Increasing water CO2, aquatic hypercapnia, leads to higher physiological pCO2 levels in fish, resulting in an acidosis and compensatory acid-base regulatory response. Senegalese sole is currently farmed in super-intensive recirculating water systems where significant accumulation of CO2 in the water may occur. Moreover, anthropogenic releases of CO...

The current volume, entitled Climate Change and Non-infectious Fish Disorders (CCNFD) is the first of the two-volume set, and it focuses on the development, physiology and health of fish. CCNFD has 11 chapters organized into two parts. Chapters 1 and 2 (Part I) are mainly for aquatic biologists including colleagues who study non-infectious fish dis...

The current volume, entitled Climate Change and Non-infectious Fish Disorders (CCNFD) is the first of the two-volume set, and it focuses on the development, physiology and health of fish. CCNFD has 11 chapters organized into two parts. Chapters 1 and 2 (Part I) are mainly for aquatic biologists including colleagues who study non-infectious fish dis...

A 18S ribosomal RNA gene partial sequence for Scyliorhinus canicula

Lay Summary Young-of-the-year lake sturgeon living in waters of high alkalinity are susceptible to mortality when exposed to 3-trifluoromethyl-4-nitrophenol (TFM), a pesticide used to control invasive sea lamprey in the Great Lakes. This risk may be reduced, however, by delaying TFM treatments to late-summer/fall, when sturgeon are larger and accum...

The dendritic organ (DO) is a salt secretory organ in the Plotosidae marine catfishes. The potential role of the DO in ammonia excretion was investigated by examining the effects of salinity [brackishwater (BW 3‰), seawater (SW 34‰) and hypersaline water (HSW 60‰)] acclimation and DO ligation on ammonia excretion and ammonia transporter expression...

Within a species' distribution, populations are often exposed to diverse environments and may thus experience different sources of both natural and sexual selection. These differences are likely to impact the balance between costs and benefits to individuals seeking reproduction, thus entailing evolutionary repercussions. Here, we look into an unus...

We examined mechanisms of ammonia handling in the anterior, mid, and posterior intestine of unfed and fed freshwater rainbow trout (Oncorhynchus mykiss), with a focus on the Na⁺:K⁺:2Cl⁻ co-transporter (NKCC), Na⁺:K ⁺-ATPase (NKA), and K⁺ channels. NKCC was localized by immunohistochemistry to the mucosal (apical) surface of enterocytes, and NKCC mR...

Pacific spiny dogfish (Squalus suckleyi) have been widely used as a representative species for chondrichthyan CO2 excretion. Pacific spiny dogfish have a slower red blood cell (RBC) carbonic anhydrase (CA) isoform than teleost fishes, extracellular CA activity, no endogenous plasma CA inhibitor, and plasma-accessible CA IV at the gills. Thus, both...

The origin of extracellular digestion in metazoans was accompanied by structural and physiological alterations of the gut. These adaptations culminated in the differentiation of a novel digestive structure in jawed vertebrates, the stomach. Specific endoderm/mesenchyme signalling is required for stomach differentiation, involving the growth and tra...

Amphibious fishes have evolved a variety of physiological modifications allowing them to survive in water and air. In air, the amphibious mangrove rivulus, Kryptolebias marmoratus, uses its skin as a site of ionoregulation. Skin ionocytes actively transport ions into/out of the body; however, it is unclear if there are specific morphological or fun...

Unique amongst the teleost, Plotosidae catfish possess a dendritic organ (DO) as a purported salt secreting organ, whereas other marine teleosts rely on their gill ionocytes for active NaCl excretion. To address the role of the DO in ionregulation, ligation experiments were conducted in brackish water (BW) 3‰ and seawater (SW) 34‰ acclimated Plotos...

Plos-one-humane-endpoints-checklist. (DOCX)

Primer nucleotide sequences and amplicon sizes for RT-PCR and qPCR. Primers used in the present study for RT-PCR and qPCR (actb, β-Actin; atp1a1, Na+/K+-ATPase; cftr, cystic fibrosis transmembrane conductance regulator; ca17, cytosolic carbonic anhydrase; slc26a6, Putative Anion Transporter Cl-/HCO3- exchanger gene). (DOCX)

RT-PCR profiles. Tested genes include actb, β-Actin; atp1a1, Na+/K+-ATPase; cftr, cystic fibrosis transmembrane conductance regulator; ca17, Cytosolic carbonic anhydrase; slc26a6, Putative Anion Transporter Cl-/HCO3- exchanger. (DOCX)

Real time RT-PCR conditions using iQ SYBR green supermix. actb, β-Actin; atp1a1, Na+/K+-ATPase; cftr, cystic fibrosis transmembrane conductance regulator; ca17, cytosolic carbonic anhydrase; slc26a6, Putative Anion Transporter Cl-/HCO3- exchanger gene. (DOCX)

Representative western blots. The figure shows immunoreactive bands for (a) NKA α-subunit (~100kDa), (b) VHA B subunit (56kDa), Ca17 (30kDa), hsp70 (70 kDa) and α tubulin (50 kDa). Ladder 250, 150, 100, 75, 50, 37.5 25 kDa (All Blue Prestained Protein Standards, BioRad). (DOCX)

In all vertebrates studied to date, CO2 excretion depends on the enzyme carbonic anhydrase (CA) that catalyses the rapid conversion of HCO3- to CO2 at the gas-exchange organs. The largest pool of CA is present within red blood cells (RBC) and, in some vertebrates, plasma-accessible CA (paCA) isoforms participate in CO2 excretion. However, teleost f...

The invasion of land required amphibious fishes to evolve new strategies to avoid toxic ammonia accumulation in the absence of water flow over the gills. We investigated amphibious behaviour and nitrogen excretion strategies in six phylogenetically diverse Aplocheiloid killifishes (Anablepsoides hartii, Cynodonichthys hildebrandi, Rivulus cylindrac...

Unlike other marine teleosts, the Plotosidae catfishes reportedly have an extra-branchial salt secreting dendritic organ (DO). Salinity acclimation [brackishwater (BW) 3aaa, seawater (SWcontrol) 34aaa, and hypersaline water (HSW) 60aaa] for 14 days was used to investigate the osmoregulatory abilities of Plotosus lineatus through measurements of blo...

Nucleotide sequences and amplicon sizes of primers used in the present study for RT-PCR and qPCR (actb, β-actin; atp1a1, Na+/K+-ATPase; cftr, Cystic fibrosis transmembrane conductance regulator; ca17, Cytosolic carbonic anhydrase; slc26a6, Putative Anion Transporter Cl-/HCO3- exchanger gene.

(A) RT-PCR and (B) qPCR profiles (actb, β-actin; atp1a1, Na+/K+-ATPase; cftr, Cystic fibrosis transmembrane conductance regulator; ca17, Cytosolic carbonic anhydrase; slc26a6, Putative Anion Transporter Cl-/HCO3- exchanger gene).

Comparisons of the amino acid sequence identities of Plotosus lineatus Atp1a1, Cftr, Ca17 and Slc26a6 partial sequences with respective orthologues from channel catfish (I. punctatus), zebrafish (D. rerio) and rainbow trout (O. mykiss).

Immunoblotting tissue profile from P. lineatus Cftr (160 kDa), NKCC (240 kDa), NKA (100 kDa), V-ATPase (56 kDa) and Ca17 (30 kDa). Bars (left) indicate bands of interest. Gi, Gill; Kd, Kidney; DO, Dendritic organ; AI, Anterior Intestine; PI, Posterior Intestine; Rc, Rectum; Br, Brain; Li, Liver; Mu, Muscle.

Na+/K+-ATPase α-subunit (Atp1a) phylogenetic tree. The evolutionary history was inferred using the Neighbor-Joining method. The optimal tree with the sum of branch length = 0.85546745 is shown. The percentage of replicate trees in which the associated taxa clustered together in the bootstrap test (1000 replicates) are shown next to the branches. Th...

Senegalese sole Solea senegalensis is currently farmed in recirculation aquaculture systems that often involve water re-oxygenation, which in turn may cause acute or prolonged hyperoxia exposures. In order to understand the impact of acute hyperoxia on the fish immune system and peripheral tissues such as gills and gut, Senegalese sole juveniles (3...

Freshwater organisms actively take up ions from their environment to counter diffusive ion losses due to inhabiting hypo-osmotic environments. The mechanisms behind active Na(+) uptake are quite well understood in freshwater teleosts, however, the mechanisms employed by invertebrates are not. Pharmacological and molecular approaches were used to in...

Dietary ion content is known to alter the acid-base balance in freshwater fish. The current study investigated the metabolic impact of acid-base disturbances produced by differences in dietary electrolyte balance (DEB) in the meagre (Argyrosomus regius), an euryhaline species. Changes in fish performance, gastric chyme characteristics, pH and ion c...

The total rate of N-waste excretion (MN) in juvenile tambaqui living in ion-poor Amazonian water comprised 85 % ammonia-N (MAmm-N) and 15 % urea-N (MUrea-N). Both occurred mainly across the gills with only ~5 % of MAmm-N and ~39 % of MUrea-N via the urine. Tambaqui were not especially tolerant to high environmental ammonia (HEA), despite their grea...

In rainbow trout, the dominant site of Na(+) uptake (J(Na)in) and ammonia excretion (Jamm) shifts from the skin to the gills over development. Post-hatch (PH; 7 days post-hatch) larvae utilize the yolk sac skin for physiological exchange, whereas by complete yolk sac absorption (CYA; 30 days post-hatch), the gill is the dominant site. At the gills,...

The stomach, which is characterized by acid peptic digestion in vertebrates, has been lost secondarily multiple times in the evolution of the teleost fishes. The Cypriniformes are largely seen as an agastric order; however, within the superfamily Cobitoidea, the closely related sister groups Nemacheilidae and Balitoridae have been identified as gas...

Alignment of the oligopeptide used to generate the NAK121 and αR1 antibodies with the corresponding amino acid sequences from Xenopus tropicalus Atp1a1, Atp4a, and Atp12a. (DOCX)

Nucleotide sequences of the different sets of primers used to test for the presence of atp4a sequence in C. macracanthus, B. histrionica, B. kweichowensis, and M. anguillicaudatus. (DOCX)

Alignment of a partial sequence of gastric HKα1 (ATP4A) in a number of vertebrates. ATP1A1 and ATP12A in H. sapiens and X. tropicalis are shown for comparison. Red boxes: Potassium binding by lysine (K) protonated at pH<3 and Glutamate (E) with two sites. Blue box: Cysteine (C) is inhibited by omeprazole (SCH28080). (DOCX)

Immunohistochemical localization of HKα1 using the C2 antibody in the stomach of the outgroup (a) Siluriformes channel catfish (Ictalurus punctatus) and (b) Characiformes Mexican tetra (Astyanax mexicanus). Images are overlaid with DAPI and DIC. Scale bar 100μm. (DOCX)

Nucleotide sequence of primers for β-actin and atp4a degenerate and consensus primers. (DOCX)

The state of the art of research on the environmental physiology of marine fishes is reviewed from the perspective of how it can contribute to conservation of knowledge for conservation of marine fishes is the limited knowledge base; international collaboration is needed to study the environmental physiology of a wider range of species. Multifactor...

Carbonic anhydrase plays a key role in CO2 transport, acid-base and ion regulation and metabolic processes in vertebrates. While several carbonic anhydrase isoforms have been identified in numerous vertebrate species, basal lineages such as the cyclostomes have remained largely unexamined. Here we investigate the repertoire of cytoplasmic carbonic...

Ongoing climate change is predicted to affect the distribution and abundance of aquatic ectotherms owing to increasing constraints on organismal physiology, in particular involving the metabolic scope (MS) available for performance and fitness. The oxygen- and capacity-limited thermal tolerance (OCLTT) hypothesis prescribes MS as an overarching ben...

Oxygen supply to the heart of most teleosts, including salmonids, relies in partor inwhole on oxygen-depleted venous blood. Given that plasma-accessible carbonic anhydrase (CA) in red muscle of rainbow trout has recently been shown to facilitate oxygen unloading from arterial blood under certain physiological conditions, we tested the hypothesis th...