Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Teleost”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 703 records · Page 39Linked to original sources
PubMed1984

Diffusion of chloride ions in the mucus on the oesophagus of Enophrys bison, a marine teleost fish.

Microelectrodes sensitive to Cl- have been used to estimate the diffusion coefficient for Cl- in the mucus on the oesophagus of a marine teleost fish, Enophrys bison. The estimate was 0.231 X 10(-5) cm2s-1. This value is significantly less than the value in saline or in seawater. The technique was based on a simple interpretation of Ficks 1st law. The flux of Cl- across an isolated, everted preparation of oesophagus was compared to the concentration gradient of Cl- within the mucous layer and its thickness and the surface area of the preparation available to diffusion.

Animals↗
PubMed1976

Influence of ouabain on the fine structure of teleost retina.

In this study the effect of intraocular injection of 10 mul 10(-5) M ouabain on the retinal fine structure of the cyprinide teleost Carassius carassius is described. The final concentration of the drug in the eye-bulb was approximately 3-10(-6)M. After 8--24 h the ouabain application produces alterations in the retinal ganglion cells, that progress subsequently to necrobiosis. The outer horizontal cells of the inner nuclear layer show a severe cytoplasmic swelling that is reversible and disappears 8 days after ouabain injection. Amacrines, bipolars and receptor cells are relatively insensitive to the ouabain-induced Na+-K+-ATPase-inhibition. The differential susceptibility to ouabain in the retina possibly reflects a cell-specific pattern of Na+-K+-ATPase-activity or -concentration, whose physiological significance is discussed.

Adenosine Triphosphate↗
PubMed1980

Certain aspects of acetylcholine metabolism in teleost retina.

Acetylcholine (ACh) synthesis and release from isolated superfused retina of the teleost Eugerres plumieri has been studied under different physiological conditions. The retinas were superfused with Krebs-Ringer solutions containing [14C]choline and the extracellular space of 32% was determined by [3H]inulin. The retina accumulates choline (Ch) from the superfusion medium and this process is mediated by a high affinity transport system with a Km of 1.82 microM. The incorporated Ch is mainly utilized for the synthesis of ACh. The ACh content of the light-adapted retina is not significantly different from that of a dark-adapted one. However, the release of [14C]ACh from the light-adapted retina was 52% higher as compared to the release from the dark-adapted retina. Flicker stimulation induced a larger increase in ACh release, than from either light or dark adapted retina, proportional to flicker frequency. The results suggest that changes in ACh utilization were related to the function of cellular units responsible for light changes transduction rather than light detection.

Acetylcholine↗
PubMed1995

Analysis of transfer RNA during the early embryogenesis of the freshwater teleost, Heteropneustes fossilis.

Total RNA as well as transfer RNA were quantified from mature ova apart from four different embryonic stages namely mid-cleavage, early gastrula, mid-gastrula and organogenesis of the freshwater teleost Heteropneustes fossilis. Total RNA as well as transfer RNA quantity follow a similar variation pattern, being maximum during mid-gastrulation. When analysed by total amino acid acceptance capacity, transfer RNA shows its maximum activity during mid-gastrulation. This coincides with the higher ratio of tRNA to total RNA at this stage. The relative aminoacylation capacity for Ser, Gly, Asn and Thr are found to be higher (9-34%) compared to that for other amino acids. Total tRNA, resolved into three peaks upon HPLC fractionation, shows a high cumulative peak area during mid-gastrulation and organogenesis. These results indicate a switch over of maternal to embryonic translation machinery during gastrulation.

Animals↗
PubMed1994

Transfer RNA analysis during the reproductive cycle of a freshwater teleost, H. fossilis.

Transfer RNA was analyzed qualitatively as well as quantitatively from ovaries of the fresh water teleost Heteropneustes fossilis for twelve months. The tRNA samples were found to be pure and devoid of any high molecular weight RNA or DNA contaminations. The quantity of tRNA as well as its biological activity, assayed by in vitro aminoacylation using homologous aminoacyl tRNA synthetases, were found to be higher during resting and preparatory (pre-vitellogenic) phases, i.e. from November to March, as compared to vitellogenic and spawning phases of the fish, i.e. from April to October. The highest tRNA pool and its activity was found in the month of February, which coincides with the early preparatory phase. The results indicate that the accumulation of active tRNA starts in the resting phase. Such an accumulation of tRNA may be a part of the enrichment of mature eggs with complete translational machinery before ovulation in order to cope with the high rate of protein synthesis after fertilization.

Amino Acyl-tRNA Synthetases↗
PubMed1977

The cytochemical demonstration of catalase and D-amino acid oxidase in the microbodies of teleost kidney cells.

The distribution of catalase and D-amino acid oxidase, marker enzymes for peroxisomes, was determined cytochemically in the kidney tubules of an euryhaline teleost, the three-spined stickleback. Catalase activity was localized with the diaminobenzidine technique. The presence of D-amino acid oxidase was determined using H2O2 generated by the enzyme, D-alanine as a substrate, and cerous ions for the formation of an electron-dense precipitate. Both enzymes appeared to be located in microbodies. The combined presence of these enzymes characterizes the microbodies as peroxisomes. Biochemically and cytochemically, no urate oxidase or glycolate-oxidizing L-alpha-hydroxy acid oxidase could be demonstrated. Stereological analysis of the epithelia lining the renal tubules showed that the fractional volume of the microbodies is 5 to 10 times higher in the cells of the second proximal tubules than in the other nephronic segments or the ureter. The fractional volume of the microbodies was similar in kidneys of freshwater and seawater fishes.

Alcohol Oxidoreductases↗
PubMed1990

Microtubule nucleation and organization in teleost photoreceptors: microtubule recovery after elimination by cold.

Retinal photoreceptors have two separate populations of microtubules: axonemal microtubules of the modified cilium of the outer segment and cytoplasmic microtubules of the cell body. The axonemal microtubules originate from a basal body located at the distal tip of the photoreceptor inner segment and extend in a 9 + 0 configuration into the outer segment of rods and accessory outer segment of cones. The cytoplasmic microtubules of the cell body are axially aligned from the distal tip of the inner segment to proximal synapse, and are oriented with uniform polarity, their minus ends distal toward the outer segment and plus ends proximal toward the synapse (Troutt & Burnside, 1988). To investigate how this regular cytoplasmic microtubule array is generated, we have attempted to identify microtubule nucleation sites in the cones of the tropical teleost fish, Tilapia (Sarotherodon mossambicus) by examining the regrowth of cytoplasmic microtubules after cold disruption in whole retinas or in isolated cone fragments consisting of inner and outer segments (CIS-COS). Incremental stages of microtubule reassembly were examined both by electron microscopy of thin sections and by immunofluorescent localization of microtubules with an antitubulin antibody. Cold treatment completely abolished all cytoplasmic microtubules but did not disrupt axonemal microtubules. Within 2 min after rewarming, cytoplasmic microtubules reappeared in the most distal portion of the inner segment in a small aster-like array associated with the basal body, and subsequently appeared in more proximal parts of the cone. These observations suggest that a favoured microtubule nucleation site is associated with the basal body region of the cone outer segment, and thus that the basal body region could function as a microtubule organizing centre for the photoreceptor. These results are consistent with the findings of our previous investigation of cone microtubule polarity, which showed that the minus ends of the cytoplasmic microtubules of the cone are associated with the basal body region.

Animals↗
PubMed1982

Pineal innervation of the third ventricular ependyma in the teleost, Puntius sophore (Ham.).

In the teleost Puntius sophore a well defined pineal tract intersects the posterior commissure at right angles and enters the ependymal layer in the roof of the third ventricle. In the ependymal layer it gives out varying number of branches which are in morphological contact with the component cells. Few branches apparently project into the third ventricles also. Further, EM studies would confirm the site of their constituent axonal endings. Such a direct pineal pathway projecting into the ependyma and third ventricle may be of great functional importance.

Animals↗
PubMed1979

Studies on the colour-change mechanism in a fresh-water teleost, Nandus nandus (Ham.). I. Neural control.

The existence and nature of chromatic fibres controlling the colour-change mechanism in the teleost, Nandus nandus has been studied by means of spinal sectioning at various vertebral levels of the animal between vertebrae 3 to 10. Spinal sectioning at or anterior to 5th vertebra completely eliminated the neural control of colour-change. As a result, the animal darkened to its maximum and the neural responses of different backgrounds were abolished. Spinal sectioning at or posterior to vertebra 6 did not affect the melanophores and at the same time did not interfere with the normal background responses of the animal. This study clearly shows that the chromatic fibres in this species run in the spinal cord and leave the latter at 5/6th vertebral level. Effect of adrenaline in the chromatic spinal-sectioned fish shows that the fibres innervating the melanophores are aggregating in nature and adrenergic in character. The results also suggest that the dispersed condition of pigment in the melanophores represents the "resting state" of the melanophores when they are under no stimulation.

Adaptation, Physiological↗
PubMed1982

Ultrastructure of scales in a teleost (Carassius auratus L.) after use of rapid freeze-fixation and freeze-substitution.

New data on the ultrastructural features of the elasmoid scales of Carassius auratus have been obtained by use of rapid freezing with subsequent freeze-substitution in anhydrous solvents. These are compared with the results obtained using conventional aqueous fixatives. The external layer of the scales is composed of randomly oriented collagen fibres. In the first stages of mineralization, mineral deposits are located in the interfibrillary substance where dense granules appear to be active sites of mineralization. Spheritic mineralization occurs in this layer. The fibrillary plate is composed of two kinds of collagen fibres. Most of them are organized in lamellae forming the "plywood-like structure". They are thicker than the so-called "TC fibres", which are oriented from the basal part towards the superficial layer. These TC fibres are involved in the first stages of mineral deposition in the fibrillary plate where inotropic mineralization occurs. The mineral phase is almost always located in the interfibrillary matrix in both layers of the elasmoid scale. In this respect, teleost scales differ from those described so far in other lower vertebrates.

Animals↗
PubMed1983

Localization of ionic pathways in the teleost opercular membrane by extracellular recording with a vibrating probe.

We have adapted the vibrating probe extracellular recording technique to use on an epithelium under voltage clamp in an Ussing chamber. The vibrating probe allows very low drift measurements of current density immediately over the epithelial surface. These measurements allowed sites of electrogenic transport in the epithelium to be localized with a spatial resolution of 5 micrometers. The technique was applied to the opercular membrane of the teleost fish, the tilapia, Sarotherodon mossambicus. The mitochondrion-rich "chloride cells" were shown to be the only sites of electrogenic ion transport in this heterogeneous epithelium. Cell sampling experiments demonstrated variable negative short-circuit currents associated with nearly all of approximately 300 chloride cells examined, which appeared to account for all of the tissue short-circuit current. Current-voltage relations for individual cells were also measured. Conductance associated with chloride cells (i.e. cellular and junctional pathways) accounted for all but 0.5 mS/cm2 of the tissue conductance, with the balance apparently accounted for by leak pathways near the edge of the tissue. Current and conductance associated with other cell types was at least 50-fold smaller than for the chloride cell. Chloride-free solutions reduced chloride cell current and conductance by 98 and 95%, respectively.

Animals↗
PubMed1996

Ascorbic acid protects against male infertility in a teleost fish.

An animal unable to synthesize ascorbic acid uniquely mimicks human and non-human primates. Therefore, in this study we used the rainbow trout, a teleost fish, as the model animal to study the importance of dietary ascorbic acid on the fertilizing ability of sperm. A high concentration of ascorbic acid in semen plays a key role in maintaining the genetic integrity of sperm cells, by preventing oxidative damage to sperm DNA. This study will show that the concentration of ascorbic acid in seminal plasma reflects the dietary intake of vitamin C. The concentration of ascorbic acid in seminal plasma of fish declined significantly in groups fed either an ascorbate-free diet (from 4.74 +/- 0.9 to 0.16 +/- 0.08 microgram ml-1) or an ascorbate-rich diet (from 37.9 +/- 4.7 to 17.7 +/- 3.2 microgram ml-1) during the spermiation season. The relationship between ascorbate status and fertility was studied in six groups of fish fed graded levels of ascorbic acid, which spermiated over a 150-day-period. Sperm from individual males was used to fertilize several batches of eggs. When the seminal plasma ascorbate concentration decreased to 7.3 microgram ml-1 a significant decrease of fertilization rate and the hatching rate of embryos resulted. This is the first evidence that dietary ascorbate level directly affected sperm quality and influenced male fertility in a scurvy-prone vertebrate.

Animals↗
PubMed1977

Metabolic energy requirements during teleost melanophore adaptations.

Inhibition of oxidative phosphorylation by 2,4-dinitrophenol or sodium cyanide promotes complete melanosome aggregation in teleost melanophores. This aggregation is not promoted via the alpha-sympathetic receptor sites because it occurs in the presence of tolazoline hydrochloride, an alpha-receptor blocking agent. Interpretation of these results suggests metabolic energy release is required in the centrifugal direction only.

Animals↗
PubMed1981

Toxicity of Temik (aldicarb) for a fresh water teleost, Barbus conchonius Hamilton.

The toxic effects of Temik (aldicarb) on a fresh water Himalayan lake teleost, Barbus conchonius were investigated in hard and soft water. The 48-, 72- and 96-h TLm-values in mg/l were 8.99, 2.39 and 2.42 respectively in the hard-water test and 3.30, 0.62 and 0.46 in the soft-water test. The toxicity of Temik to B. conchonius increases many fold in soft water.

Aldicarb↗
PubMed1980

Artificial spawning effected in the fresh water teleost, Cyprinus carpio by clomiphene citrate.

Triweekly i.m. injections of clomiphene citrate (group 1, 25 micrograms/0.5 ml and group II, 50 micrograms/1.0 ml) were administered for a period of 3 months during the preparatory period to female fresh water teleosts exhibiting ovarian recrudescence, while a control group received 0.5 ml of physiological saline throughout the period of experimentation i.e., from February through April. 50 micrograms clomiphene citrate treatment brought about a steady increase in ovarian size, and oocytes began to enlarge and mature and finally ovulation took place in April. This is 4 months ahead of their normal occurrence.

Animals↗
PubMed1979

Mercuric chloride induced enzymological changes in kidney and ovary of a teleost fish, Channa punctatus.

The effect of LC(50) (1.8 MG/L) and a sublethal concentration (0.03 mg/L) of in vivo mercuric chloride exposure on the activities of acid and alkaline phosphatases, glucose-6-phosphatase, lipase and urease in the kidneys and ovaries of a teleost fish, Channa punctatus has been studied after 96 hr and 30 days respectively. It has been observed that the activities of all the enzymes except acid phosphatase were significantly inhibited in both the tissues. However, treatment for 96 hr resulted in more marked inhibition than 30 days of treatment. Acid phosphatase showed elevation in activity in the kidney after 96 hr of treatment.

Acid Phosphatase↗