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At least 865 records · Page 48Linked to original sources
PubMed1990

Electrophoretic study of myosin isoforms in white muscles of some teleost fishes.

1. White skeletal muscle myosin of four marine teleost fish species (cod, blue whiting, Norway haddock, and spotted wolf-fish) was analyzed by native, SDS-PAGE, and 2-dimensional electrophoresis. 2. Four types of native myosin were present in cod, blue whiting and Norway haddock. The second fastest migrating form was predominant. 3. Myosin from spotted wolf-fish also resolved into four forms. The fastest migrating form was hardly noticeable. The other three were present in apparently similar amounts. 4. In the myosin from each species there were three types of light chains. The pattern of light chains was species specific. 5. Apparently, there was only one type of heavy chain in myosin from cod, Norway haddock and spotted wolf-fish. One preparation of cod showed an extra band of higher electrophoretic mobility than the main band. In blue whiting we found two bands present in approximately equal amounts.

Animals↗
PubMed1992

Lactate dehydrogenase in teleosts. The role of LDH-C4 isozyme.

1. Lactate dehydrogenase (LDH) occupies an important position in cell metabolism. 2. Teleosts possess at least three genetic loci coding for lactate dehydrogenase subunits, Ldh-A, Ldh-B and Ldh-c. LDH exists in most tissues in several isozymic forms. 3. The isozyme LDH-C4 is synthesized predominantly in regions of the nervous system concerned with the eye.

Animals↗
PubMed1986

Differentiated retinal Müller glia are ciliated--ultrastructural evidence in the teleost Poecilia reticulata P.

It is generally held that the cells in all retinal layers bear a cilium during development but there have been controversial reports as to whether the ciliation of the Müller cell persists after birth. The present study of the developing and fully formed adult eye of the teleost Poecilia reticulata reveals that just prior to the formation of the photoreceptors in the embryonic retina, the Müller cell contains only a diplosome. Throughout development the diplosome is seen to migrate apically, always juxtaposed to many microtubules. When the photoreceptors are differentiated and capable of photomechanical movement, the Müller cell in Poecilia bears a cilium situated vitreally to the external limiting membrane. The cilium persists in juvenile and adult retinae in both the light- and dark-adapted state. The functional significance of the cilium in the Müller cell is presently unknown.

Animals↗
PubMed1992

Four synonymous genes encode calmodulin in the teleost fish, medaka (Oryzias latipes): conservation of the multigene one-protein principle.

We cloned four distinct calmodulin (CaM)-encoding cDNAs from a small teleost fish, medaka (Oryzias latipes). The deduced amino acid (aa) sequences were exactly the same in these four genes and identical to the aa sequence of mammalian CaM, because of synonymous codon usages. The four cDNAs from medaka, termed CaM-A, -B, -C and -D, corresponded to mRNAs of 1.8, 1.4, 2.5 and 1.8 kb, respectively, in Northern blot analysis. Our results demonstrated that the 'multigene one-protein' principle of CaM synthesis is applicable to medaka, as well as to mammals whose CaM is encoded by at least three different genes.

Amino Acid Sequence↗
PubMed1980

Thiodon toxicity: non-specific phosphomonoesterases in nine freshwater teleosts.

The effect of various concentrations of thiodon on tissue non-specific phosphomonoesterases was studied in 9 edible freshwater teleosts from a tropical environment. Sublethal doses (5 and 10 ppm) of thiodon increased alkaline phosphatase in liver, muscle, kidney and brain, while lethal doses (15 and 20 ppm) decreased it. The reverse was the case with acid phosphatase. The greatest changes were recorded in kidney and liver. The increase in the activity of acid phosphatase after lethal doses might be attributable to rupture of the cellular and lysosomal membranes. The decrease in alkaline phosphatase activity might be related to the fall in pH following rupture of these membranes. The changes were greater in major carp species (C. catla, L. rohita and C. mrigala) than in catfish (H. fossilis, C. batrachus and M. seenghala) or snakehead species of murrels (C. striatus, C. punctarus and C. marulius).

Acid Phosphatase↗
PubMed1980

Ammonia toxicity: metabolic disorder in nine freshwater teleosts.

An inverse relationship was recorded between the concentration of ammonium chloride (5, 10, 15, and 20 ppm) and the fall in pH and dissolved oxygen of water; with ammoniacal nitrogen and carbon dioxide the relationship was reversed. The effect of various concentrations of ammonium chloride (5, 10, 15, and 20 ppm) on tissue glycogen, serum glucose and lactate level was studied in 9 freshwater teleosts from a tropical environment. The fall in tissue (liver, muscle, and brain) glycogen was inversely proportional to ammonia concentration. An elevation in renal glycogen was recorded up to 10 ppm with a decrease thereafter. The greatest fall in tissue glycogen was recorded in the liver (C. mrigala), muscle, brain (C. catla), and kidney (C. mrigala). There was a direct relationship between ammonia concentration and accumulation of glucose and lactate in serum. The decrease in tissue glycogen was greater in major carp species than in murrels or catfish.

Ammonia↗
PubMed1981

Enzymological and biochemical changes produced by mercuric chloride in a teleost fish, Channa punctatus.

Alterations in the activities of lactate dehydrogenase, pyruvate dehydrogenase and succinate dehydrogenase in the brian, gills, intestine, kidney, liver and muscles, the levels of glycogen and lactic acid in liver and muscles, and blood glucose have been examined in a fresh-water teleost fish, Channa punctatus after exposure to a sublethal concentration (3 microgram/1) of mercuric chloride for 15, 30 and 60 days. The results revealed that the activities of all the three dehydrogenases were inhibited significantly after 60 days of treatment except for lactate dehydrogenase in brain. Glycogen and lactic acid contents of the liver and muscles and the blood glucose level also decreased significantly after 60 days of exposure. Though gills and muscles showed weak activity of the three dehydrogenases, the percentage of inhibition was more marked in these tissues than in others.

Animals↗
PubMed1982

Mercurial toxicity in the liver of a freshwater teleost Channa punctatus.

Alterations in the activities of alkaline phosphatase, acid phosphatase, glucose-6-phosphatase, succinic dehydrogenase, pyruvic dehydrogenase and lactic dehydrogenase in liver a teleost fish, Channa punctatus were examined after 7, 15 and 30 days treatments with 5 micrograms/l mercuric chloride. Observations have shown specific effects of Hg on these enzymes for a particular period. However, alkaline phosphatase, acid phosphatase, glucose-6-phosphatase were progressively inhibited by this element. Greater accumulation of Hg in liver after a longer treatment and the respective change in enzyme activity clearly showed a dose-response relationship.

Animals↗
PubMed1982

Acute and chronic effects of diazinon on the activities of three dehydrogenases in the digestive system of a freshwater teleost fish Channa punctatus.

The effect of acute exposure to LC50 for 96 h (3.1 mg/l) and chronic exposure to a sublethal concentration (0.31 mg/l) of diazinon has been studied in the liver, stomach, intestine and pyloric ceca of a freshwater teleost fish, Channa punctatus. In acute exposure succinate dehydrogenase (SDH) activity was elevated in intestine and pyloric ceca. No alteration was noted in lactate dehydrogenase activity but pyruvate dehydrogenase was inhibited in pyloric ceca. Chronic exposure resulted in inhibition of the activities of the three dehydrogenases in all the four parts at both intervals.

Animals↗
PubMed1983

Enzymological and biochemical changes produced by chronic chromium exposure in a teleost fish, Channa punctatus.

The chronic toxic effects of chromium (2.6 mg/1) on the carbohydrate metabolism of a teleost fish, Channa punctatus were examined after 60 and 120 days of exposure. After 60 days the lactic acid content of blood and muscles was increased but liver lactic acid content decreased. Liver glycogen was also depleted. The activity of lactate dehydrogenase was inhibited in liver and kidney. Pyruvate dehydrogenase and succinate dehydrogenase activities were also inhibited in all the tissues except muscles. Fish were hypoglycemic and hyperlactemic after 120 days of exposure to chromium. The glycogen content increased in liver but decreased in muscles. Lactate dehydrogenase activity was inhibited in all the six tissues. The activity of pyruvate dehydrogenase decreased in liver, intestine, gill and muscles. In muscles succinate dehydrogenase activity was elevated but inhibition was recorded in other tissues.

Animals↗
PubMed1983

Ammonia-induced change in the hepatic glutathione level of an air-breathing freshwater teleost Channa punctatus (Bloch).

Exposure to ammonia (NH4OH) for 48 h resulted in greater than 50% depletion of the hepatic glutathione pool in Channa punctatus (Bloch). Removal of fish to ammonia free ambience induced a rapid and excessive resynthesis of glutathione within 24 h. This level, however, decreased within 5 days of return to ammonia-free fresh water. It is concluded that ammonia stress in a freshwater air-breathing teleost is counteracted by the glutathione system of detoxication of xenobiotics and resynthesis of glutathione is induced by short-term exposure to ammonia followed by transfer to ammonia-free water.

Acclimatization↗
PubMed1984

Impairments induced by sublethal doses of two pesticides in the ovaries of a freshwater teleost Channa striatus Bloch.

Impairments induced by sublethal doses of two pesticides Carbaryl and Endosulfan have been studied on the ovaries of a freshwater teleost Channa striatus by exposing the fish for a period of 2 to 30 days during the spawning season. The pesticide exposure produced reduction in the number of oocytes, reduction in size and deformity in different stages of oocytes, damage to yolk vesicles in maturing and mature oocytes, increase in the number of atretic oocytes, development of interfollicular spaces, increase in the connective tissue of tunica albuginea, dilation of blood vessels and reduction in the gonadosomatic index. The histopathological effects were dependent on the dose, duration of exposure, and the type of pesticide. Sublethal doses of Endosulfan were more toxic than those of Carbaryl.

Animals↗
PubMed1983

Electric stimulation experiments on leucophores of a freshwater teleost, Oryzias latipes.

1. Electric stimulation experiments on the central nerve and on isolated scales of a freshwater teleost, Oryzias latipes, confirmed that the leucophores, like the melanophores, were controlled by the nerve. 2. AC stimulation induced pigment dispersion of the innervated leucophores. The response was not of the all or none type. 3. AC selectively acts on the nerve fibers to produce propagating excitation. 4. The transmitter released from the nerve terminals is suspected to be noradrenaline, and the postsynaptic receptor is of an adrenergic beta type.

Animals↗
PubMed1992

The dynamics of MS-222 anaesthesia in a marine teleost (Pagrus auratus: Sparidae).

1. MS-222 anaesthesia of the marine teleost Pagrus auratus caused a dose-dependent elevation in haematocrit. 2. At 60 mg/l MS-222 the elevated haematocrit was fully accounted for by erythrocyte swelling, but at 100 mg/l red cell count also increased. 3. Uptake of anaesthetic in all tissues was rapid and the rate of onset of anaesthesia was dose-dependent. 4. Stage III level of anaesthesia (loss of equilibrium) was correlated with critical levels of MS-222 in the blood and brain. 5. The presence of acetylated derivatives of MS-222 in the blood demonstrated degradation of the anaesthetic, and high levels in the liver and kidney suggested that these organs were the sites of drug metabolism.

Aminobenzoates↗
PubMedDate not supplied

Distribution of serotonin- and dopamine-immunoreactivity in the brain of the teleost Clarias gariepinus.

The distribution of serotonergic and dopaminergic cell bodies and varicose fibres in the brain of the teleost Clarias gariepinus was studied immunohistochemically using antisera against formaldehyde-conjugated serotonin and dopamine. Many serotonergic and dopaminergic fibres innervated the areas dorsalis telencephali pars medialis and pars lateralis dorsalis, as well as the area ventralis telencephali pars ventralis. In the diencephalon, a large number of serotonergic and some dopaminergic fibres were found in the preoptic nucleus, innervating the cells of this nucleus. In addition, serotonergic and dopaminergic fibres were observed in the pituitary stalk and in all regions of the pituitary gland. Moreover, the diencephalon contained the highest number of serotonin- or dopamine-immunoreactive cell bodies. These cells were confined to the same periventricular nuclei as the nucleus ventromedialis thalami, the nucleus posterior periventricularis, the nucleus lateralis tuberis, the nuclei recessus lateralis and recessus posterioris. Most cells of these nuclei were in contact with the cerebrospinal fluid of the third ventricle. The brainstem contained serotonergic cell bodies in the raphe nuclei and a few serotonergic and dopaminergic fibres. The torus semicircularis was densely innervated by serotonergic fibres and, to a lesser extent, dopaminergic fibres. In the midbrain of Clarias gariepinus, no dopaminergic homologue of the substantia nigra was observed. The results are discussed both in a comparative and a physiological context. In this regard, special attention has been paid to the contribution of hypothalamic monoamines in the regulation of gonadotropin secretion as an essential step in the neuro-endocrine control of reproduction.

Animals↗
PubMedDate not supplied

Development of tyrosine hydroxylase-, dopamine- and dopamine beta-hydroxylase-immunoreactive neurons in a teleost, the three-spined stickleback.

The development of catecholaminergic neuronal systems in the brain of a teleost, the three-spined stickleback, was studied through embryonic to early larval stages by immunocytochemistry using specific antibodies against dopamine, tyrosine hydroxylase and dopamine beta-hydroxylase. By analysing the spatiotemporal patterns of development for the catecholaminergic nuclei, possible homologies with nuclei in amniote brains have been identified. The noradrenergic neurons in the isthmus region of the rostral rhombencephalon originate in the same manner as the A4-A7 + subcoeruleus group in mammals. Their developmental characteristics show the largest similarities with the subcoeruleus group of birds and mammals, although some features are shared with developing A6 (locus coeruleus) neurons. Catecholaminergic neurons never appear during development in the ventral mesencephalon of the three-spined stickleback. A group of large dopaminergic neurons that accompany the cerebrospinal fluid (CSF)-contacting neurons follows the border between the hypothalamus and the ventral thalamus into the caudal hypothalamus, where they are continuous with the dopaminergic neurons in the posterior tuberculum. They are thus topologically comparable with the dopaminergic neurons of the zona incerta in mammals. The dopaminergic CSF-contacting neurons that line the median, lateral and posterior recesses of the third ventricle do not contain tyrosine hydroxylase-immunoreactivity at any developmental stage. This indicates that they take up and accumulate exogenous dopamine or L-dihydroxyphenylalanine, and do not synthesize dopamine from tyrosine at any developmental stage. Tyrosine hydroxylase-immunoreactive neurons appear in the pineal organ on the day of hatching (120 h post-fertilization). They were still observed in 240-h-old larvae, but are absent in the pineal organ of adult sticklebacks. The initial appearance and subsequent differentiation of catecholaminergic neurons in the stickleback embryo follow essentially the same spatial and temporal pattern as in amphibian, avian and mammalian embryos. This observation supports the hypothesis that morphologically, topologically and chemically similar monoaminergic neurons in different vertebrate classes are homologous.

Animals↗
PubMed1995

Histamine-immunoreactive neurons in the brain of the teleost Gasterosteus aculeatus L. Correlation with hypothalamic tyrosine hydroxylase- and serotonin-immunoreactive neurons.

The distribution of putative histaminergic neurons in the brain of a teleost, the three-spined stickleback, was investigated by means of immunocytochemistry using specific antibodies against histamine (HA), and conventional microscopy as well as confocal laser scanning microscopy. Histamine-immunoreactive (HAir) neurons form discrete populations ventral to the nucleus of the posterior recess (NRP) and in the nucleus saccus vasculosus (NSV), which belong to the periventricular hypothalamic nuclei. The neuronal somata are subependymally located, and do not possess apical neurites contacting the cerebrospinal fluid. They give rise to both long-range and local axonal projections. The local projections give rise to a field of dense punctate immunoreaction dorsal to the NRP and lateral to the NSV. Long-range projections are comprised of ascending projections to the thalamus, habenula, preoptic area and dorsal telencephalon; and descending projections via the posterior tuberal nucleus, ventrally to the nucleus interpeduncularis, and dorsally into the central gray. HAir neurons occur together with serotoninergic cerebrospinal fluid-contacting (CSFc) neurons in the NRP, and with tyrosine hydroxylase-immunoreactive (THir) neurons in the NSV. Although HAir elements occur together with THir ones in many brain areas, direct contacts between the two neurotransmitter systems are rare. The putative histaminergic neurons in the brain of the three-spined stickleback constitute a very discrete neuronal system, with a major projection area in the dorsal telencephalon in a region which is considered homologous with the dorsal pallium of land vertebrates.

Animals↗
PubMed1995

Ontogeny of GABA-immunoreactive neurons in the central nervous system in a teleost, gasterosteus aculeatus L.

The inhibitory neurotransmitter gamma-aminobutyric acid (GABA) is known to exert various neurotrophic actions in the developing nervous system, but little is known about its distribution in the central nervous system during early development. We have studied the development of GABA-immunoreactive (GABAir) neurons during embryogenesis of a teleost fish, the three-spined stickleback. As early as 51 h postfertilization (PF; hatching occurs 144-168 h PF, and the first monoaminergic neurons appear around 72 h PF) GABAir neurons appear in the ventral prosencephalon caudal to the optic recess, in the ventral mesencephalon, and in the spinal cord. Then, there is a gradual addition of GABAir cell groups in the rostral prosencephalon and ventral rhombencephalon (66 h PF), dorsal and caudal hypothalamus and pretectum (72 h PF), ventral hypothalamus (78 h PF), preoptic region, thalamus, and in the mesencephalon and rhombencephalon (96 h PF). GABAir axons appear in the spinal cord already at 51 h PF, and then gradually appear in the various tracts of the early axonal scaffold of pathfinding fibers, so that by 96 h PF the entire axonal scaffold contains GABAir fibers. It appears likely that GABAergic axons contribute a major population to the formation of the axonal scaffold. Moreover, in the prosencephalon GABAir neurons are arranged in clusters that may reflect a neuromeric organization with six prosencephalic neuromeres.

Animals↗