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PubMed1996

Effects of temperature and white sucker (Catostomus commersoni) serum supplement on the in vitro multiplication of Cryptobia catostomi in cell-free culture medium.

Cryptobia catostomi, a non-pathogenic haemoflagellate of white suckers (Catostomus commersoni) multiplied rapidly in modified TDL-15 medium supplemented with 10% fetal bovine serum and 1% heatinactivated white sucker serum (WSS) at 10 degrees C and 18 degrees C. The numbers of C. catostomi counted were significantly higher in cultures incubated at 10 degrees C than in those incubated at 18 degrees C beginning at 3 weeks post-incubation. The culture forms (from the eighth subculture at 9 months after isolation) were morphologically similar to blood forms and were infective to laboratory-raised white suckers. The parasite survived for about 4 weeks in the medium without WSS at 18 degrees C. The present study indicates that WSS supplement supports the in vitro multiplication of C. catostomi and that its multiplication is temperature-dependent.

Animals↗
PubMed1998

Corpuscles of Stannius and stanniocalcin-like immunoreactivity in the white sucker (Catostomus commersoni): evidence for a new cell-type.

The distribution of stanniocalcin immunoreactivity was examined in the corpuscles of Stannius of the white sucker (Catostomus commersoni) by using a chum salmon stanniocalcin antiserum, Western blotting, and light and electron microscopy. The white sucker possesses at least two stanniocalcin-immunoreactive corpuscles in the most posterior portions of the kidneys. Immunocytochemistry and ultrastructure revealed two cell-types in the corpuscle parenchyma, only one of which was immunoreactive. The nonimmunoreactive cells contained dense-cored vesicles and long processes that extended between the immunoreactive cells and terminated at perivascular spaces. When corpuscle extracts were subjected to electrophoresis and Western blotting, three nonreduced stanniocalcin-like immunoreactive bands (approximately 56, 61, and 64 kDa) were observed. However, in the presence of a reductant, a diffuse band migrating in the range of 28 to 32 kDa was noted. The results of this study on the white sucker demonstrate the presence of a dimeric stanniocalcin-like molecule and present evidence of a previously uncharacterized cell-type in the corpuscles of Stannius.

Animals↗
PubMed2005

Reference values for exposure to PAH contaminants: Comparison of fish from Ohio and Mid-Atlantic streams.

Reference values for background exposures of benzo[a]pyrene (BAP)- and naphthalene (NAPH)-type metabolites were calculated for white sucker, northern hog sucker, and rock bass from the mid-Atlantic region based on the 90th percentile of a probability-based sample. Preliminary findings are presented for common carp. Bile was collected from fish and assayed for polycyclic aromatic hydrocarbon metabolites using the fluorescent method of Lin et al. Exposure reference values for white sucker were 0.3 microg/mg protein for BAP-type metabolites and 40 microg/mg protein for NAPH-type metabolites. Values from the Mid-Atlantic region were similar to those previously reported for the Eastern Corn Belt Plains (ECBP) ecoregion. Exposure reference values of BAP-type metabolites for rock bass were 0.3 microg/mg protein and 0.4 microg/mg protein for northern hog sucker. Exposure reference values of NAPH-type metabolites for rock bass were 30 microg/mg protein for rock bass and 50 microg/mg protein for northern hog sucker. Provisional values for common carp based on 39 observations are 0.4 microg/mg protein for BAP-type metabolites and 120 microg/mg protein for NAPH-type metabolites. Small streams exhibited the greatest range of exposures, 0.015-0.689 microg/mg protein for BAP-type metabolites and from 5.7 to 159 microg/mg protein for NAPH-type metabolites. Larger streams had 0.11-0.859 microg/mg protein for BAP-type metabolites and 10.2-286.5 microg/mg protein for NAPH-type metabolites. Exposure reference values for BAP and NAPH-type metabolites could be used as a basis of comparison of exposure to PAH contamination.

Animals↗
PubMed2006

A tandemly repetitive centromeric DNA sequence of the fish Hoplias malabaricus (Characiformes: Erythrinidae) is derived from 5S rDNA.

A substantial fraction of the eukaryotic genome consists of repetitive DNA sequences that include satellites, minisatellites, microsatellites, and transposable elements. Although extensively studied for the past three decades, the molecular forces that generate, propagate and maintain repetitive DNAs in the genomes are still discussed. To further understand the dynamics and the mechanisms of evolution of repetitive DNAs in vertebrate genome, we searched for repetitive sequences in the genome of the fish species Hoplias malabaricus. A satellite sequence, named 5SHindIII-DNA, which has a conspicuous similarity with 5S rRNA genes and spacers was identified. FISH experiments showed that the 5S rRNA bona fide gene repeats were clustered in the interstitial position of two chromosome pairs of H. malabaricus, while the satellite 5SHindIII-DNA sequences were clustered in the centromeric position in nine chromosome pairs of the species. The presence of the 5SHindIII-DNA sequences in the centromeres of several chromosomes indicates that this satellite family probably escaped from the selective pressure that maintains the structure and organization of the 5S rDNA repeats and become disperse into the genome. Although it is not feasible to explain how this sequence has been maintained in the centromeric regions, it is possible to hypothesize that it may be involved in some structural or functional role of the centromere organization.

Animals↗
PubMed2006

Banding pattern of A and B chromosomes of Prochilodus lineatus (Characiformes, Prochilodontidae), with comments on B chromosomes evolution.

B chromosomes in Prochilodus lineatus, a migratory neotropical fish, were analyzed in a comparative study among populations from the Dourada lagoon (State of Paraná, Brazil) and from Mogi-Guaçu river (State of São Paulo, Brazil). The data on C-banding and fluorescent in situ hybridization with a satellite DNA probe (SATH1), indicate that the small metacentric B chromosome might correspond to an isochromosome. On the other hand, both populations presented a distinct set of B chromosomes, differentiated either by their number and by the presence of variant B types in the population from Mogi-Guaçu river. The present results indicate that the B chromosomes of P. lineatus should have an ancient origin, and have undergone a differential evolutionary pathway among distinct populations.

Animals↗
PubMed2006

Phylogenetic conservation of chromosome numbers in Actinopterygiian fishes.

The genomes of ray-finned fishes (Actinopterygii) are well known for their evolutionary dynamism as reflected by drastic alterations in DNA content often via regional and whole-genome duplications, differential patterns of gene silencing or loss, shifts in the insertion-to-deletion ratios of genomic segments, and major re-patternings of chromosomes via non-homologous recombination. In sharp contrast, chromosome numbers in somatic karyotypes have been highly conserved over vast evolutionary timescales - a histogram of available counts is strongly leptokurtic with more than 50% of surveyed species displaying either 48 or 50 chromosomes. Here we employ comparative phylogenetic analyses to examine the evolutionary history of alterations in fish chromosome numbers. The most parsimonious ancestral state for major actinopterygiian clades is 48 chromosomes. When interpreted in a phylogenetic context, chromosome numbers evidence many recent instances of polyploidization in various lineages but there is no clear indication of a singular polyploidization event that has been hypothesized to have immediately preceded the teleost radiation. After factoring out evident polyploidizations, a correlation between chromosome numbers and genome sizes across the Actinopterygii is marginally statistically significant (p = 0.012) but exceedingly weak (R (2) = 0.0096). Overall, our phylogenetic analysis indicates a mosaic evolutionary pattern in which the forces that govern labile features of fish genomes must operate largely independently of those that operate to conserve chromosome numbers.

Amphibians↗
PubMedDate not supplied

Gene mapping of 28S and 5S rDNA sites in the spined loach Cobitis taenia (Pisces, Cobitidae) from a diploid population and a diploid-tetraploid population.

We compare the chromosomal 28S and 5S rDNA patterns of the spined loach C. taenia (2n = 48) from an exclusively diploid population and from a diploid-polyploid population using 28S and 5S rDNA probe preparation and labelling, and fluorescence in situ hybridization (FISH). The 5S rDNA was located in two to three chromosome pairs, and separated from the 28S loci for the males and one female (F1) from the diploid population. Loaches from a diploid-polyploid population, and one female (F2) from the diploid population were characterized by at least one chromosome pair with 5S and 28S overlapping signals. The fishes differed mainly in their number of 28S rDNA loci, located on 3-6 chromosomes. All individuals from both populations were characterized by one acrocentric chromosome bearing a 28S rDNA signal on the telomeres of its long arm. The number of major ribosomal DNA in the karyotype of C. taenia by FISH was always higher than the number of Ag-NORs. Our data confirm the extensive polymorphism of NORs in both populations, as already has been observed in closely related Cobitis species, and less polymorphic 5S rDNA pattern. However, this preliminary result highlights the need for a wider scale study.

Animals↗
PubMed2007

The gynogenetic reproduction of diploid and triploid hybrid spined loaches (Cobitis: Teleostei), and their ability to establish successful clonal lineages--on the evolution of polyploidy in asexual vertebrates.

Polyploidisation is assumed to have played a significant role in the evolution of hybrid asexual lineages. The virtual absence of natural asexual systems in which more than a single ploidy level successfully establishes successful independent clonal lineages is generally explained by the strong effects of polyploidisation on fitness. Experimental crosses were made between diploid and triploid asexual Cobitis elongatoides x C. taenia hybrids (female) and both parental spined loach species (male). Genotyping of the progeny using allozymes and multilocus DNA fingerprinting, along with flow cytometric measurement of ploidy level, demonstrated the occurrence of gynogenetic reproduction in both female biotypes. The incorporation of the sperm genome occurred in some progeny, giving rise to a higher ploidy level, but the rate of polyploidisation differed significantly between the diploid and triploid females. These outcomes are consistent with the existence of developmental constraints on tetraploidy, which determine the rarity of tetraploids in natural populations. No cases of ploidy level reduction were observed. Since diploid and triploid hybrid populations occur where the lack of potential progenitor excludes the possibility of de novo origin, it is probable that both diploid and triploid females can establish successful clonal lineages. Spined loaches represent a unique example, among asexual vertebrates, where more than one ploidy level can establish persistent clonal lineages, which are reproductively independent of one another.

Animals↗
PubMed1990

Molecular cloning of two distinct vasotocin precursor cDNAs from chum salmon (Oncorhynchus keta) suggests an ancient gene duplication.

The structures of two different vasotocin precursors from chum salmon brain have been elucidated through the molecular cloning of their corresponding cDNAs. Although the predicted precursors, consisting respectively of 153 and 158 amino acids, have the same structural organisation, they show 35% amino acid sequence divergence, of which only approximately half are isofunctional substitutions. Remarkably, while the C terminal segments of both precursors resemble the glycopeptide moiety of the related mammalian vasopressin precursor, both salmon precursors lack consensus sequences for N-glycosylation.

Amino Acids↗
PubMed1991

The delivery of foreign genes into fertilized fish eggs using high-velocity microprojectiles.

Fertilized eggs of loach (Misgurnus fossilis), rainbow trout (Salmo gairdneri) and zebrafish (Brachydanio rerio) were bombarded with high-velocity tungsten microprojectiles covered with plasmid DNA containing sequences of beta-galactosidase and neomycin phosphotransferase genes. About 70% of the eggs survived the bombardment. The activity of both transferred genes was revealed in the fish developed from the bombarded eggs. Neomycin phosphotransferase gene sequences were detected by means of PCR amplification and Southern hybridization in the total DNA of zebrafish that survived after G418 treatment.

Animals↗
PubMed1994

The expression of different annexins in the fish embryo is developmentally regulated.

The expression of annexins, a family of Ca2+/phospholipid-binding proteins, was analyzed by biochemical and immunological criteria in the fish Misgurnus fossilis (loach), which is a good model system to study embryonic events. Five different annexins (loach annexins A to E) are present as a maternal pool in the unfertilized eggs. Only annexin E is newly synthesized in the early embryo. Its synthesis, already apparent at mid-blastula, decreases in later stages when two additional annexins (F and G) appear. They are present among the newly synthesized polypeptides of mid-gastrula and later embryonic stages and are also found in loach larvae. The developmentally controlled expression of several annexins indicates a specific role of these proteins at certain embryonic stages.

Animals↗
PubMed1986

Effects of [D-Ala6, Pro9-NEt]-LHRH and catecholaminergic drugs on gonadotropin secretion and ovulation in the Chinese loach (Paramisgurnus dabryanus).

The effects of [D-Ala6,Pro9-NEt]-LHRH (LHRH-A) alone and in combination with drugs which influence the actions of dopamine or the synthesis of catecholamines on gonadotropin (GtH) secretion and ovulation in the loach (Paramisgurnus dabryanus) were investigated. LHRH-A alone stimulated an increase in serum GtH levels in the loach, but was a relatively ineffective treatment for the induction of ovulation. Injection of the dopamine receptor antagonist pimozide caused a marked potentiation of the GtH-release response to LHRH-A, and combined injections of pimozide and LHRH-A were an effective treatment for the induction of ovulation. Reserpine, a drug which causes depletion of catecholamines from presynaptic terminals, also caused a marked potentiation of the GtH-release response to LHRH-A and combined treatment induced ovulation. Similarly, administration of alpha-methyl-para-tyrosine to block conversion of tyrosine to L-dopa, or carbidopa to block conversion of L-dopa to dopamine, potentiated the GtH-release response to LHRH-A and induced ovulation. In contrast, the use of diethyldithiocarbamate, to block conversion of dopamine to norepinephrine, failed to augment the action of LHRH-A on GtH release and ovulation. The present results provide further evidence to suggest that dopamine functions as a gonadotropin release-inhibitory factor in teleosts, and demonstrate that the use of drugs which block either the synthesis or the actions of dopamine potentiates the action of LHRH-A in teleosts.

Animals↗
PubMed1988

Effects of [D-Arg6, Trp7, Leu8, Pro9NEt]-luteinizing hormone-releasing hormone (sGnRH-A) and [D-Ala6, Pro9NEt]-luteinizing hormone-releasing hormone (LHRH-A), in combination with pimozide or domperidone, on gonadotropin release and ovulation in the Chinese loach and common carp.

The effects of LHRH-A and sGnRH-A alone and in combination with the dopamine receptor antagonists pimozide (PIM) and domperidone (DOM) on stimulation of gonadotropin (GtH) secretion and ovulation in Chinese loach (Paramisgurnus dabryanus) and common carp (Cyprinus carpio) were studied. When tested in the absence of a dopamine receptor antagonist, sGnRH-A was about 10-fold more potent than LHRH-A in stimulating GtH secretion in loach, whereas these peptides were of similar effectiveness in common carp. Both peptides were effective alone in inducing ovulation in loach, but were ineffective in common carp. PIM and DOM stimulate a small but significant increase in serum GtH, and greatly potentiate the effects of LHRH-A and sGnRH-A on GtH secretion and ovulation in both species. DOM was of equal or somewhat greater potency than PIM in potentiating the action of releasing hormone agonists in loach; however, DOM had markedly greater effectiveness in common carp. sGnRH-A in the presence of DOM was more effective than LHRH-A in stimulating GtH secretion and ovulation in common carp. The present studies suggest that there are marked differences in the relative contribution of GnRH and dopamine in the control of GtH secretion in loach and common carp, and indicate in particular that the more intense dopaminergic inhibitory control of GtH release in common carp modifies the responsiveness of the pituitary to GnRH peptides.

Animals↗
PubMed1987

The effect of local cortical microfilament disorganization on ooplasmic segregation in the loach (Misgurnus fossilis) egg.

Injections of cytochalasin D (CD) or DNase I under the surface of fertilized loach egg result in local disorganization of microfilamentous cortex (MC) as revealed by transmission electron microscopy. This effect correlates with the loss of the cortex ability to contract in vitro. The disorganization of MC in the vegetal hemisphere of the egg does not affect the ooplasm segregation or blastodisk cleavage. Injection under the animal pole suppresses blastodisk formation and results in the autonomous separation of ooplasm in the central part of the egg. The experiments suggest that (1) autonomous separation of ooplasm from the yolk granules can proceed in the central part of the egg without the participation of MC; (2) normal segregation of ooplasm at the animal pole requires that the structures of microfilaments in the animal hemisphere (but not in the vegetal one) be preserved.

Actin Cytoskeleton↗
PubMed1990

Pathogenesis of skin and liver neoplasms in white suckers from industrially polluted areas in Lake Ontario.

Increased prevalences of epidermal and hepatobiliary neoplasms in white suckers (Catostomu commersoni) and brown bullheads (Ictalurus nebulosus) in the Western region of Lake Ontario have been associated with industrial pollution, but the identity and causative role of environmental carcinogens have not yet been established. Most epidermal tumors of lip and body skin are benign focal proliferations that occur in fish from the polluted Hamilton region, and also in fish from less polluted sites in the Great Lakes. These skin tumors in white suckers do not have consistent alterations in cellular glutathione S-transferases (GST), suggesting that growth of skin tumors is not promoted by chemicals normally detoxified by GST. However, elevated levels of glutathione peroxidase (GPO) and glutathione reductase (GR) in skin papillomas are indicative of promotional peroxidative tissue injury, either caused directly by xenobiotics or indirectly by chemical-induced inflammation. Liver tumors in white suckers from Lake Ontario include preneoplastic, benign, and malignant populations of hepatocellular and biliary cells, all of which are more prevalent in fish from polluted sites. These liver tumors are consistently associated with chronic cholangiohepatitis and segmental cholangiofibrosis, but these conditions also occur in white suckers in non-industrial locations. Thus, the natural occurrence of biliary disease, not attributable to industrial pollution, may have some influence on the development of liver tumors. Some preneoplastic lesions and the majority of neoplastic hepatocellular and biliary lesions in white suckers have low levels of total GST, indicating that these liver neoplasms are not promoted by xenobiotics normally detoxified by hepatic GSTs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗