Fish Invertebrates Research Articles

The ag1 gene is required for the fin regeneration in Danio rerio

Abstract—We have recently demonstrated that the Ag1 protein is necessary for the fin regeneration in Danio rerio fish. Robust activation of the ag1 gene expression in cells of the wound epithelium is observed after caudal fin amputation. Moreover, the inhibition of translation of ag1 mRNA leads to the retardation of the caudal fin regeneration. The results of our research are important because the ag1 gene is contained only in lower vertebrates (fish and amphibians) with good regenerative capacity, whereas this gene is missing in higher vertebrates, which are not capable of the efficient limb regeneration. Our data indicate that the reduction of the potential regenerative ability in higher vertebrates including humans can be explained by the extinction of some genes, particularly the ag1 gene, essential for regeneration.

A new Cenomanian vertebrate tracksite at Tamajón (Guadalajara, Spain): Palaeoichnology and palaeoenvironmental implications

A new Upper Cretaceous vertebrate tracksite has been discovered at Tamajón (Iberian Ranges, Guadalajara, Spain). The track level is a relatively smooth and slightly undulating sandy ferruginous crust, corresponding to an erosive surface at the base of a small meandering channel. It is incised into the underlying planar cross-bedded sandstones of coastal bars located at the middle-upper part of the Utrillas Formation (middle-upper Cenomanian). The site shows an extraordinary concentration of vertebrate tracks, among which numerous sets of two to five isolated digit impressions (“swim tracks”) and, at least, two trackways referred to crocodyliforms, and a single tridactyl footprint probably produced by a theropod dinosaur can be recognized. There are also several long traces (epichnial grooves) revealing sharp direction changes (up to 90°) which seem to be fish fin traces (Undichna unisulca), although crocodyliforms (tail marks) and/or fish invertebrates cannot be rejected as possible tracemakers. Some crocodyliform tracks reveal a thin raised rim, due to the displacement of the sediment by the pressure produced by the feet. Several impressions are moderately deformed by small sediment slides, only preserving their deepest part (claw marks). This is clearly indicative of a soft substrate with a high degree of plasticity and water content at the time of the track registration. Nevertheless, the sediment was hard enough to preserve manus and pes print morphologies and also possible crocodyliform tail and/or fish fin traces. Small rhizoliths can also be recognized and may belong to herbaceous wetland vegetation. The morphology of the palaeochannel, the sedimentary context and the track preservation seem to indicate that the tracks were impressed in a shallow channel located near the coast, under wet conditions and in different moments of time. This discovery represents the first occurrence of vertebrate ichnites in the Utrillas Formation, a stratigraphic unit where osteological and ichnological remains are relatively scarce, and it confirms that some crocodyliforms lived in near coast channels during the deposition of this unit.

Heavy metal interactions during accumulation via direct route in fish: a review

Among vertebrates fish are unique as they have two routes of metal acquisition: from water via gills and from the diet via the gut (direct and trophic uptake routes). The direct uptake route is more important because gills are the main target-organ for metal toxicity in fish. The majority of studies into metal toxicity and accumulation in fish are focused on single metals. However, in the natural environment, fish are exposed to multimetal mixtures, toxicity levels of which usually differ from those of single metals as their effect can be additive, higher than additive (synergistic), or sometimes lower than additive (antagonistic). This article deals with the role of heavy metal interactions during accumulation in fish organs/tissues, especially with regard to uptake via direct route of water-borne metals. Although the influence of the presence of particular metals in ambient water on accumulation of other metals in fish has been proved experimentally, such studies are still quite scarce, often fragmental...

Spatial variation in the littoral vertebrate community of a reservoir relative to physical and biological gradients.

Reservoirs possess gradients in conditions and resources along their long (deep-shallow) axis, but the response of littoral vertebrates (fish and turtles) to these gradients is poorly understood. We have quantified the littoral vertebrate communities throughout a small reservoir in Southeastern Ohio during July and August using traps, and related community composition to environmental variables using NMDS ordination. Ordination revealed that fish and turtles were broadly separated in ordination space, and three distinctly different environmental gradients were significantly associated with the underlying observed species abundances. Observed turtle abundance was explained by measurements of bathymetry, turbidity, and benthic resources, but none of these environmental variables were a reliable predictor of observed fish abundance. Temperature was a poor predictor of observed abundance for both fish and turtles independently, but when fish and turtles were considered together, it became apparent that there were cold areas of the reservoir where observed fish and turtle abundances were different than in other areas of the reservoir. These results suggest that the predictor (environmental) variables we used were appropriate for investigating turtle ecology in reservoirs, but that observed fish abundance is mediated by factors that were not modeled. The efficacy of using traps, the ecological implications of considering fish and turtles together as sympatric and potentially competing species, and directions for future study are discussed.

Analýza aktuálních kompetencí žáků a studentů v určování českých druhů obratlovců

This study focuses on research into the practical knowledge of primary and secondary school students. It is aimed at exploring common species of vertebrates (fish, amphibians, reptiles, birds and mammals) in the Czech Republic. It builds on research byLang and Pravda, 1971. It takes a large part of their methodology and compares the results with selected reference species. The results are presented in graphs and tables.

Specific IgEs passively transferred through a platelet transfusion caused two discrete allergic reactions to food

Case report A non-atopic 8 year old boy received multiple blood product transfusions as part of his treatment for meduloblastoma. He subsequently experienced anaphylaxis to salmon. Within minutes of eating salmon, he developed angioedema of the lip, facial erythema, throat discomfort and low blood pressure. Before this episode, he regularly ate fish with no reaction. The passive transfer of food specific IgE was suspected and he was advised to carry an epinephrine auto-injector and avoid all vertebrate fish. Specific IgE to salmon by ImmunoCAP was positive. Follow-up was arranged to follow his specific IgE to salmon with the expectation that his allergy would resolve. One week after his anaphylactic episode to fish, he developed an allergic reaction to peanuts. He ate a chocolate peanut butter cup and within 10 minutes he vomited, developed angioedema of the lip and experienced lethargy. Previously, he routinely ate peanuts without any symptoms. Skin prick testing showed positive results to peanut, salmon, mixed fish, and tree nut mix. He had a positive ImmunoCAP to peanut. Approximately 6 months later, he had undetectable ImmunoCAP results to both salmon and peanut. He resumed consumption of salmon and peanuts with no reaction. As part of the adverse event investigation by Canadian Blood Services all donors associated with the reaction were contacted and one donor stated that they have a severe allergy to peanuts, tree nuts, shellfish, and all fish including salmon. This information implicated one specific pooled platelet transfusion in which the platelets were suspended in the plasma of the atopic donor. The donor has been excluded from future donations. Conclusions

Zebrafish as a Natural Host Model for Vibrio cholerae Colonization and Transmission

The human diarrheal disease cholera is caused by the aquatic bacterium Vibrio cholerae. V. cholerae in the environment is associated with several varieties of aquatic life, including insect egg masses, shellfish, and vertebrate fish. Here we describe a novel animal model for V. cholerae, the zebrafish. Pandemic V. cholerae strains specifically colonize the zebrafish intestinal tract after exposure in water with no manipulation of the animal required. Colonization occurs in close contact with the intestinal epithelium and mimics colonization observed in mammals. Zebrafish that are colonized by V. cholerae transmit the bacteria to naive fish, which then become colonized. Striking differences in colonization between V. cholerae classical and El Tor biotypes were apparent. The zebrafish natural habitat in Asia heavily overlaps areas where cholera is endemic, suggesting that zebrafish and V. cholerae evolved in close contact with each other. Thus, the zebrafish provides a natural host model for the study of V. cholerae colonization, transmission, and environmental survival.

The complete mitochondrial genome of the fourfinger threadfin Eleutheronema tetradactylum (Perciforms: Polynemidae) and comparison of light strand replication origin within Percoidei

The complete mitochondrial genome of Eleutheronema tetradactylum was determined, which was the first complete mitochondrial genome in Polynemidae family. The mitochondrial genome was 16,474 base pairs in length, encoding a standard set of 13 protein-coding genes, 2 ribosomal RNA genes, 22 tRNA genes and 2 main non-coding regions (the control region and the origin of the light strand replication). The overall base composition of E. tetradactylum is A 27.2%, C 29.9%, G 17.0% and T 25.9%, with a slight A + T bias of 53.1%. The mitochondrial genome of E. tetradactylum had common features about gene arrangement and tRNA structures compared with those of other vertebrate fishes. Two non-coding regions were also determined within its mitogenome. These mitogenome sequence data would play an important role in population genetics and phylogenetic analysis of the Polynemidae.

In vitro characterization of the RS motif in N-terminal head domain of goldfish germinal vesicle lamin B3 necessary for phosphorylation of the p34cdc2 target serine by SRPK1

The nuclear envelopes surrounding the oocyte germinal vesicles of lower vertebrates (fish and frog) are supported by the lamina, which consists of the protein lamin B3 encoded by a gene found also in birds but lost in the lineage leading to mammals. Like other members of the lamin family, goldfish lamin B3 (gfLB3) contains two putative consensus phosphoacceptor p34cdc2 sites (Ser-28 and Ser-398) for the M-phase kinase to regulate lamin polymerization on the N- and C-terminal regions flanking a central rod domain. Partial phosphorylation of gfLB3 occurs on Ser-28 in the N-terminal head domain in immature oocytes prior to germinal vesicle breakdown, which suggests continual rearrangement of lamins by a novel lamin kinase in fish oocytes. We applied the expression-screening method to isolate lamin kinases by using phosphorylation site Ser-28-specific monoclonal antibody and a vector encoding substrate peptides from a goldfish ovarian cDNA library. As a result, SRPK1 was screened as a prominent lamin kinase candidate. The gfLB3 has a short stretch of the RS repeats (9-SRASTVRSSRRS-20) upstream of the Ser-28, within the N-terminal head. This stretch of repeats is conserved among fish lamin B3 but is not found in other lamins. In vitro phosphorylation studies and GST-pull down assay revealed that SRPK1 bound to the region of sequential RS repeats (9–20) with affinity and recruited serine into the active site by a grab-and-pull manner. These results indicate SRPK1 may phosphorylate the p34cdc2 site in the N-terminal head of GV-lamin B3 at the RS motifs, which have the general property of aggregation.

Vitellogenesis in Archigetes sieboldi Leuckart, 1878 (Cestoda, Caryophyllidea, Caryophyllaeidae), an intestinal parasite of carp (Cyprinus carpio L.).

Vitellogenesis in the caryophyllidean tapeworm Archigetes sieboldi Leuckart, 1878, from carp Cyprinus carpio L. in Slovakia, has been examined using transmission electron microscopy and cytochemical staining with periodic acid-thiosemicarbazide-silver proteinate (PA-TSC-SP) for glycogen. Vitelline follicles extend in two lateral bands in the medullary parenchyma along both sides of the monozoic body. They are surrounded by an external basal lamina and contain vitellocytes and an interstitial tissue. The general pattern of vitellogenesis is essentially like that of other caryophyllideans. It involves four stages: immature, early maturing, advanced maturing cells and mature vitellocytes. During vitellogenesis, a continuous increase in cell volume is accompanied by an extensive development of cell components engaged in shell globule formation, e.g. granular endoplasmic reticulum and Golgi. Shell globule clusters are membrane-bound. Nuclear and nucleolar transformation are associated with formation and storage of large amounts of intranuclear glycogen, a very specific feature of the Caryophyllidea. For the first time, (a) additional vitelline material in Archigetes is represented by lamellar bodies and (b) lipid droplets are described in the mature vitellocytes from vitelline follicles and vitelloduct of the Caryophyllidea. Our results indicate that there may be a double origin of lamellar bodies: either from the endoplasmic reticulum or through transformation of shell globule/shell globule clusters. Lamellar body clusters and some single lamellar bodies appear to have a membrane. Other ultrastructural features of vitellogenesis and/or vitellocyte in A. sieboldi from its vertebrate (fish) and invertebrate (oligochaete) hosts are briefly compared and contrasted with those in other caryophyllideans and/or Neodermata.

Food protein–induced enterocolitis syndrome can occur in adults

Food protein–induced enterocolitis syndrome can occur in adults

Eocene (Lutetian) Shark-Rich Coastal Paleoenvironments of the Southern North Sea Basin in Europe: Biodiversity of the Marine Fürstenau Formation Including Early White and Megatooth Sharks

The Fürstenau Formation (Lutetian, Paleogene, Eocene) is based on type sections near Fürstenau in Germany (central Europe) and is built of 22 meter thick marine glauconitic and strongly bioturbated sands, clays, and a vertebrate-rich conglomerate bed. The conglomerate layer from the Early Lutetian transgression reworked Lower Cretaceous, and Paleogene marine sediments. It is dominated by pebbles from the locally mountains which must have been transported by an ancient river in a delta fan. Marine reworked Lower Cretaceous and Paleogen pebbles/fossils, were derived from the underlying deposits of northern Germany (= southern pre North Sea basin). The benthic macrofauna is cold upwelling water influenced and non-tropical, and medium divers. The vertebrate fish fauna is extremely rich in shark teeth, with about 5,000 teeth per cubic meter of gravel. The most dominant forms are teeth from sand shark ancestors Striatolamia macrota, followed by white shark ancestors Carcharodon auriculatus. Even teeth from the magatooth shark ancestor Carcharocles sokolovi are present in a moderately diverse and condensed Paleogene fish fauna that also includes rays, chimaeras, and more then 80 different bony fish. Fragmentary turtle remains are present, and few terrestrial vertebrates and even marine mammals with phocids, sirenians and possibly whales.

Incorporation of Tyrosine and Glutamine Residues into the Soluble Guanylate Cyclase Heme Distal Pocket Alters NO and O2 Binding

Nitric oxide (NO) is the physiologically relevant activator of the mammalian hemoprotein soluble guanylate cyclase (sGC). The heme cofactor of alpha1beta1 sGC has a high affinity for NO but has never been observed to form a complex with oxygen. Introduction of a key tyrosine residue in the sGC heme binding domain beta1(1-385) is sufficient to produce an oxygen-binding protein, but this mutation in the full-length enzyme did not alter oxygen affinity. To evaluate ligand binding specificity in full-length sGC we mutated several conserved distal heme pocket residues (beta1 Val-5, Phe-74, Ile-145, and Ile-149) to introduce a hydrogen bond donor in proximity to the heme ligand. We found that the NO coordination state, NO dissociation, and enzyme activation were significantly affected by the presence of a tyrosine in the distal heme pocket; however, the stability of the reduced porphyrin and the proteins affinity for oxygen were unaltered. Recently, an atypical sGC from Drosophila, Gyc-88E, was shown to form a stable complex with oxygen. Sequence analysis of this protein identified two residues in the predicted heme pocket (tyrosine and glutamine) that may function to stabilize oxygen binding in the atypical cyclase. The introduction of these residues into the rat beta1 distal heme pocket (Ile-145 --> Tyr and Ile-149 --> Gln) resulted in an sGC construct that oxidized via an intermediate with an absorbance maximum at 417 nm. This absorbance maximum is consistent with globin Fe(II)-O(2) complexes and is likely the first observation of a Fe(II)-O(2) complex in the full-length alpha1beta1 protein. Additionally, these data suggest that atypical sGCs stabilize O(2) binding by a hydrogen bonding network involving tyrosine and glutamine.

Mechanisms of Achromatic Vision in Invertebrates and Vertebrates: A Comparative Study

Intracellular recording in the retina of the snail, Helix pomatia L., reveals the existence of two types of cell responsive to diffuse flashes of achromatic or monochromatic light: B-type cells, which respond with sustained depolarization that is sometimes accompanied by spikes, and D-type cells, which respond with sustained hyperpolarization. The peak of spectral sensitivity for both B- and D-cells falls in the 450-500 nm range and coincides with range of maximal sensitivity for the rhodopsin family of photopigments. Within a proposed two-channel model of snail achromatic vision, responses of the B- and D-cells are represented by a two-dimensional 'excitation vector'. The length of the 'excitation vector' is approximately constant, and its direction correlates with light intensity. The vector model of light encoding in the snail is discussed in relation to models of achromatic vision in vertebrates (fish, frog, monkey, and humans) based on psychophysical, behavioral and neurophysiological data. Intracellular data in the snail taken together with data from vertebrate animals support the hypothesis that a 2-dimensional model of brightness and darkness encoding utilizes a universal mechanism of 'vector encoding' for light intensity in neuronal vision networks.

Paranucleospora theridion n. gen., n. sp. (Microsporidia, Enterocytozoonidae) with a Life Cycle in the Salmon Louse (Lepeophtheirus salmonis, Copepoda) and Atlantic Salmon (Salmo salar)

Paranucleospora theridion n. gen, n. sp., infecting both Atlantic salmon (Salmo salar) and its copepod parasite Lepeophtheirus salmonis is described. The microsporidian exhibits nuclei in diplokaryotic arrangement during all known life-cycle stages in salmon, but only in the merogonal stages and early sporogonal stage in salmon lice. All developmental stages of P. theridion are in direct contact with the host cell cytoplasm or nucleoplasm. In salmon, two developmental cycles were observed, producing spores in the cytoplasm of phagocytes or epidermal cells (Cycle-I) and in the nuclei of epidermal cells (Cycle-II), respectively. Cycle-I spores are small and thin walled with a short polar tube, and are believed to be autoinfective. The larger oval intranuclear Cycle-II spores have a thick endospore and a longer polar tube, and are probably responsible for transmission from salmon to L. salmonis. Parasite development in the salmon louse occurs in several different cell types that may be extremely hypertrophied due to P. theridion proliferation. Diplokaryotic merogony precedes monokaryotic sporogony. The rounded spores produced are comparable to the intranuclear spores in the salmon in most aspects, and likely transmit the infection to salmon. Phylogenetic analysis of P. theridion partial rDNA sequences place the parasite in a position between Nucleospora salmonis and Enterocytozoon bieneusi. Based on characteristics of the morphology, unique development involving a vertebrate fish as well as a crustacean ectoparasite host, and the results of the phylogenetic analyses it is suggested that P. theridion should be given status as a new species in a new genus.

About mechanisms of triggering of primary excitation rhythms in vertebrates (Phylo- and ontogenetic aspects of the problem)

There has been performed the comparative-ontogenetic analysis of literature and of our own data obtained at study of regularities of formation of spontaneous stereotypic motor acts at the initial stages of the human fetuses and at early stages of phylogenesis of vertebrates (fish, amphibians, reptiles) as well as at using natural biological models, such as anencephaly of human fetus, the human artificially produced therapeutic electroconvulsive fit, and hibernation in mammals. This analysis has allowed showing that the prenervous and non-nervous motorics and cardiac rhythm revealed in the vertebrate line, including human fetus, represent a universal phenomenon that is due to the role of prenervous transmitters as local hormones participating in triggering and regulation of this motorics-the primary rhythms of excitation in vertebrate phylo-and ontogenesis.

Amphibian Declines Are Not Uniquely High amongst the Vertebrates: Trend Determination and the British Perspective

Although amphibians have experienced major global declines and an increasing extinction rate, recent results indicate that they are not as uniquely disadvantaged as previously supposed. Acquisition of robust data is evidently crucial to the determination of both absolute and relative rates of biodiversity declines, and thus in prioritising conservation actions. In Britain there is arguably a longer history of recording, and attempting to conserve, a wide range of species groups than anywhere else in the world. This stems from the early activities of Victorian naturalists in the nineteenth century, the establishment of natural history societies and, since the mid-twentieth century, a range of national recording schemes and organisations actively involved in conservation. In this review we summarise comparative evidence for British amphibians and reptiles concerning historical abundance, population trends and their causes, and outline how they relate to the situation elsewhere in Europe (and possibly the World). We discuss possible reasons why the plight of ectothermic vertebrates (fish, amphibians and reptiles) seems generally worse than that of endotherms (birds and mammals), as well as research priorities and factors likely to impact amphibians and reptile conservation in future.

A coelacanthid-rich site at Hasbergen (NW Germany): taphonomy and palaeoenvironment of a first systematic excavation in the Kupferschiefer (Upper Permian, Lopingian)

Plants, invertebrates and fish vertebrates were studied in an excavation campaign of the 30-cm-thick Upper Permian Kupferschiefer Member (Werra Formation: Lower Zechstein, Lopingian) in the Huggel (Osnabrucker Bergland, NW Germany). Taphonomy was mapped at six different planal levels on a 12 m2 area. Plant remains belong mainly to terrestrial conifers Ullmannia frumentaria (Schlotheim) and Pseudovoltzia liebeana (Geinitz), and rare Quadrocladus solmsii (Gothan and Nagelhard). Marine invertebrates consist mainly of the common nautilid Peripetoceras freieslebeni (Geinitz). Of importance is a rich fish fauna with rare skeletons of elasmobranchs Wodnika striatula Munster and Janassa bituminosa (Schlotheim) and numerous actinopterygians, dominated (83%) by Palaeoniscum freieslebeni Blainville as juvenile to adult individuals in different stages of disarticulation. Other, rarer, ray-finned species, including Pygopterus humboldti Agassiz, Platysomus striatus Agassiz, Eurysomus macrurus (Agassiz), Dorypterus hoffmanni Germar and Acentrophorus glaphyurus (Agassiz) are typical for the diverse European Late Permian Zechstein Sea fauna. Most important are concentrations of Coelacanthus granulatus Agassiz (3% of total), also represented by juvenile to adults. Fossil density variation within the Kupferschiefer reflects paleoenvironment in a shallowing-up sequence and bathymetrical change from deeper water to zones close to coastal patch reefs. The shallow-water submarine swell zone at Hasbergen can be related to uplift of the regional Huggel Horst. Charcoalified wood indicates forest fires, and palaeocurrent orientation of fossils correlates with the paleoclimatic of SW Passat wind-direction models based formerly on palaeodune analyses.

Zebrafish ( Danio rerio) neuromast: Promising biological endpoint linking developmental and toxicological studies

Aquatic toxicology is facing the challenge to assess the impact of complex mixtures of compounds on diverse biological endpoints. So far, ecotoxicology focuses mainly on apical endpoints such as growth, lethality and reproduction, but does not consider sublethal toxic effects that may indirectly cause ecological effects. One such sublethal effect is toxicant-induced impairment of neurosensory functions which will affect important behavioural traits of exposed organisms. Here, we critically review the mechanosensory lateral line (LL) system of zebrafish as a model to screen for chemical effects on neurosensory function of fish in particular and vertebrates in general. The LL system consists of so-called neuromasts, composed of centrally located sensory hair cells, and surrounding supporting cells. The function of neuromasts is the detection of water movements that is essential for the fish’s ability to detect prey, to escape predator, to socially interact or to show rheotactic behaviour. Recent advances in the study of these organs provided researchers with a broad area of molecular tools for easy and rapid detection of neuromasts dysfunction and/or disturbed development. Further, genes involved in neuromasts differentiation have been identified using auditory/mechanosensory mutants and morphants. A number of environmental toxicants including metals and pharmaceuticals have been shown to affect neuromasts development and/or function. The use of the LL organ for toxicological studies offers the advantage to integrate the available profound knowledge on developmental biology of the neuromasts with the study of chemical toxicity. This combination may provide a powerful tool in environmental risk assessment.

COMMUNITY-WIDE RAMIFICATIONS OF AN ASSOCIATIONAL REFUGE ON SHALLOW ROCKY REEFS

Little attention has been given to associational refuges in ecology, despite their potential for maintaining species diversity and supporting higher trophic levels. Here I show how the colonial anemone, Corynactis californica, creates a refuge for benthic macroalgae and invertebrate fish prey on intensively grazed shallow rocky reefs in the Santa Barbara Channel off southern California, U.S.A. On reefs heavily grazed by sea urchins, benthic macroalgae and invertebrate fish prey were relatively more abundant among Corynactis colonies than adjacent areas lacking the anemone. Results from field experiments showed that Corynactis facilitated the recruitment of macroalgae and tubicolous amphipods in "urchin-barren" areas subjected to intensive grazing. In areas forested by giant kelp (Macrocystis pyrifera), where grazing intensity from urchins was low, Corynactis suppressed algal recruitment but facilitated tubicolous amphipods. A manipulation of fish and sea urchins suggested that grazing by urchins, as opposed to predation from fish (primarily surfperch Embiotocidae), suppressed tubicolous amphipods, and this activity was hindered by the presence of Corynactis. In systems where human activity has intensified herbivory, associational refuges may maintain species diversity and support higher trophic levels.