Cytoplasmic inclusions in the oogenesis of ophiocephalus punctatus

Summary TheGolgi apparatus can be seen in the usual juxtanuclear position in a very young oocyte. Later, the mass increases in size and resolves itself into very minuteGolgi spheres which disperse gradually in the general cytoplasm. There is some evidence of the infiltrati on of theGolgi bodies from the follicular epithelium to the egg. The granular mitochondria arise also in the juxtanuclear area, and with the increase in the size of the oocyte they get dispersed in the cytoplasm. The filamentar and beaded mitochondria appear in the older oocytes. Fatty yolk arises through the agency of theGolgi bodies by the swelling of aGolgi granule or by the deposition of new material on the concave side of one or more crescenticGolgi bodies. Albuminous yolk appears to be formed directly or indirectly by mitochondria. With 8 figures in the text.     

The effect of starvation on energy turnover and protein metabolism in Ophiocephalus punctatus bloch

1. At 20°C, fish starved for various durations took less food than unstarved fish. At 28°C, 20-day starved fish alone consumed more food.
2. The maximum feeding was during the second ten days at 28°C but in the first ten days at 20°C.
3. Absorption efficiency was unaffected by temperature and starvation.
4. Absorption rate reflected feeding rate.
5. At 28°C the conversion efficiency was high for the ten-day starved fish but at 20°C the 30-day starved fish showe high conversion efficiency.
6. Conversion rate is governed not only by feeding rate but also by conversion efficiency.
7. At 28°C the 20-day starved fish alone compensated for loss of energy, total and protein nitrogen. At 20°C the loss was compensated for by all fish.

     

The effect of temperature on the consumption,absorption and conversion of food in Ophiocephalus punctatus bloch

1. The overall feeding rate is maximum at 28°C and decreases at 20°C and 33°C for all sizes.
2. The smaller fish are cold-sensitive. At 28°C and at 33°C the time course rate shows the same decline, whereas at 20°C the response was anomalous.
3. Absorption efficiency is independent of size and temperature.
4. Rate of absorption and hence rate of conversion is primarily conditioned by rate of feeding.
5. At 20°C the conversion efficiency is directly related to size whereas at 28°C and 33°C it is inversely related to size.

     

Insulin regulates ionic metabolism in a fresh water teleost, anabas testudineus (bloch)

Short term effects of insulin on total brain and branchial Na+K+ ATPase, Ca2+ ATPase and Na+, K+ and Ca2+ ions were investigated in A. testudineus. The increase in brain Ca2+ ATPase after alloxan treatment may account for an increased amount of intracellular calcium required for biochemical events taking place inside the cells. Branchial Na+K+ATPase was significantly stimulated while Ca2+ ATPase significantly inhibited after alloxan treatment. This suggests that alloxan exerts its inhibitory effect on the ATP-driven Ca2+ transport via; its action on the Ca2+ pump protein rather than the membrane permeability to Ca2+. The increased activity of brain Na+K+ ATPase at 3 and 24 hr by insulin to alloxan pretreated fish may account for the stimulated co-transport of glucose and its utilization for energy requirements and the excitatory action on neurons in the brain. The elevated brain Ca2+ ATPase may be due to the role of calcium as a second messenger in hormone action. At 24 hr, the activity of branchial Na+K+ ATPase and Ca2+ ATPase in alloxan pretreated specimens was significantly stimulated by insulin. This may be due to increased synthesis of these enzyme units. Administration of insulin (lU/fish) in normal fish significantly inhibited the activity of brain and branchial Na+K+ ATPase while brain Ca2+ ATPase showed a stimulatory effect at 3 and 24 hr compared to control. Inhibition of total branchial Ca2+ ATPase activity by insulin may be due to increased Ca2+ concentration. Higher plasma glucose level in alloxan treated groups confirms the diabetic effect of alloxan. Insulin reverses this effect. The possible mechanism by which insulin controls Na+K+ ATPase activity appears to be tissue specific. The results seem to be the first report on the effect of insulin on ATPase activity in a teleost. These data are consistent with the hypothesis that insulin performs a role in hydro mineral regulation in freshwater teleosts.     

Protein metabolism in goldfish brain

Abstract— Protein metabolism of goldfish brain was studied in vivo by means of intraperitoneal or intracranial injections of [³H]leucine and compared with concomitant studies in the mouse. Heterogeneity of turnover values was observed. Long turnover times were seen relative to other organs examined. The free amino acid pools of goldfish brain were determined, and the fate of tritium from labelled leucine was followed at various times after injection. Following ‘chasing’ with large amounts of unlabelled leucine or protein inhibitors shortly after isotope injection, further incorporation was arrested, but examination of the labelled protein over a period of 2 weeks indicated a slow decay, similar to that seen without ‘chasing’. Possible use of ‘pulse-chase’ experiments in vivo in animals is discussed in relation to behavioural studies.     

Protein metabolism in Isoparorchis hypselobagri.

Isoparorchis hypselobagri was maintained in a non-nutrient medium containing streptomycin and penicillin to prevent bacterial growth for a period of 12 hours. The parasites were kept under aerobic conditions at a suitable temperature of 30 degrees C. The protein content in Isoparorchis hypselobagri ranged from 56.25% to 67.5% with an average of 63.5%+/-4.6 of dry seight of the tissue. The nitrogen of Isoparorchis hypselobagri excreted as ammonia, after 12 hours of starvation was 3.04% of the total body nitrogen and as uric acid 1.6% of total body nitrogen.     

Protein metabolism in preimplanted mouse ova

Intracellular specific radioactivity of an amino acid (leucine) was measured in preimplantation mouse ova. The measured specific activity along with leucine incorporation rates allow calculation of the protein synthetic rate in mouse ova. Unfertilized ova, fertilized ova, two-cell ova, and blastocysts convert amino acid to protein at the rate of 8.60, 7.36, 6.92, and 56.68 × 10^?13 moles of amino acid per hour per ovum, respectively. The specific activity measurements also allowed the calculation of intracellular leucine pool size. For the unfertilized, fertilized, two-cell, and blastocyst stage, the endogenous leucine pool was 11.9, 15.9, 6.4, and 62.4 × 10^?14 moles of leucine, respectively. Most of the increase in pool size in the blastocyst probably results from the increase in total volume of cells. Protein degradation measurements indicated a marked difference between protein turnover in the two-cell and blastocyst stage. Approximately 10% of the protein at the two-cell stage turns over with a half-life of 18.3 hr and 35% of the protein at the blastocyst stage turns over with a half-life of 11.2 hr. The large remaining fraction of protein turns over much more slowly.     

Protein metabolism in an astroglial primary culture

Protein metabolism was studied in astroglial primary cultures, grown for different time periods. Removal of fetal calf-serum for two days led to a morphological differentiation consisting of retraction of cell soma and extension of processes. There was a prominent decrease in total soluble protein and a decrease in [³H]valine incorporation into soluble protein. Dibutyrylcyclic-3-5-adenosine monophosphate (dB-cAMP)-treatment for two days also changed morphology in a similar way, but had no effect on [³H]valine incorporation into protein. After addition of soluble brain extract to the cultures an increased [³H]valine incorporation into soluble protein was seen together with a morphological differentiation, more pronounced in the presence than in the absence of fetal calf-serum. Proteins were secreted from the cells into the incubation medium and studied by electrophoresis. The more prominent protein bands had m.w. in the region of 10,000–100,000 daltons. The amount of newly synthesized proteins released into the medium was unchanged (or decreased slightly in 14 and 16 day old cultures) after addition of dB-cAMP or soluble brain extract, and was much reduced after removal of fetal calf-serum.     

Protein metabolism during endurance exercise

After reviewing all the available results from our laboratory and numerous reports in the literature concerning changes that have occurred in various aspects of protein metabolism during exercise, a number of conclusions can be drawn with some degree of confidence. During exercise, protein synthesis is depressed and this change leaves amino acids available for catabolic processes. The rate of leucine oxidation appears to be increased during exercise, and there is a movement of amino acids, mostly in the form of alanine, from muscle to liver where the rate of gluconeogenesis is increased as a result of exercise. These changes in protein metabolism are probably physiologically significant in at least three ways: amino acid conversion to citric acid cycle intermediates enhances the rate of oxidation of acetyl-CoA generated from glucose and fatty acid oxidation; increased conversion of amino acids to glucose helps to prevent hypoglycemia; oxidation of some amino acids may provide energy for muscular contraction.     

Isolation and characterization of microsatellites in Zosterisessor ophiocephalus (Perciformes,Gobiidae)

We isolated and characterized 10 polymorphic microsatellite loci from two partial genomic libraries of Zosterisessor ophiocephalus (Perciformes, Gobiidae), enriched for AC and for multiple motifs. Variability was tested on specimens from the Venice lagoon revealing a high degree of genetic variation. The loci will be useful for monitoring the biodiversity of the species at the genetic level and for parentage assessment purposes.