Interference of benzo[a]pyrene with cytochrome P-450-mediated steroid metabolism in pyloric caeca microsomes of the sea star Asterias rubens L.

• 1.1. The effects of benzo[a]pyrene (BaP) on the metabolism of progesterone and pregnenolone, and the effects of steroids on BaP metabolism were examined in pyloric caeca microsomes of female Asterias rubens.
• 2.2. The patterns of metabolism of progesterone and pregnenolone in microsomes were similar to those found in previous studies for homogenates and tissue incubations of pyloric caeca.
• 3.3. BaP reduced the rate of hydroxylation of progesterone and pregnenolone, but had no effect on metabolite formation by non-cytochrome P-450-catalysed reactions.
• 4.4. Microsomal BaP hydroxylase activity was reduced by the presence of progesterone, but pregnenolone and testosterone had no such effect.
• 5.5. The reductions in steroid or BaP metabolism were progressive with increasing ratios of the concentration of the interfering compound to that of the assay substrate and were maximally 50% or less at ratios of × 100.
• 6.6. It is concluded that isoenzymic forms of cytochrome P-450 are present, with preferences towards either steroid or BaP metabolism. The implications of the results for the in vivo situation are discussed.

     

Fate of ingested leucine and glucose in the sea star,Asterias rubens,during its annual reproductive cycle

• 1.1. The distribution of radiolabel from L-leucine [¹⁴C-UL] and D-glucose [¹⁴C-UL] was measured in the sea star Asterias rubens at 1, 6 and 24 hr after oral administration.
• 2.2. Incorporation of the label from both compounds was observed in pyloric caeca, coelomocytes and ovaries even after an incubation time of 1 hr.
• 3.3. Highest incorporation from both precursors was found in proteins, while substantial radioactivity was present in the amino acids, organic acids and neutral components. Lipids were hardly labelled from leucine and only slightly from glucose.
• 4.4. Radioactivity in proteins and lipids increased with increasing incubation time. No significant differences were found in the distribution patterns of radiolabel during the reproductive cycle.
• 5.5. The data obtained are discussed in terms of current knowledge on the translocation of nutrients in echinoderms.

     

Effect of photoperiod on steroid metabolism in the sea star Asterias Rubens L

• 1.1. The effect of photoperiod on steroid metabolism in Asterias rubens was studied.
• 2.2. Daylength was artificially shortened in 3 weeks from long-day (LD 18/6) to short-day (LD 6/18) conditions and its effect on the metabolism of pregnenolone and dehydroepiandrosterone was studied in homogenates of gonad and pyloric caeca tissue from male and female seastar.
• 3.3. Pregnenolone metabolism did not change during the experiment when the animals were kept continuously under the same (long-day) conditions. Pregnenolone metabolism was intensified by decreasing daylength. The production of progesterone reached its maximum at a daylength comparable to that in autumn (LD 12/12), and that of an unidentified steroid at an even shorter daylength.
• 4.4. Metabolism of dehydroepiandrosterone was influenced by photoperiod. There were indications that androstenedione production is maximal at fall conditions. This was evident for an as yet unidentified steroid.
• 5.5. Metabolism of DHEA strongly increased during the experiment in animals which were kept continuously under long-day conditions. It is discussed that this may be a reaction to crowding.

     

Variations in the levels of progesterone in Mytilus edulis during the annual reproductive cycle

• 1.1. Progesterone levels in Mytilus edulis males and females during the annual reproductive cycle were analysed in the whole animal and in the gonads using gas-liquid chromatography and radioimmunoassays.
• 2.2. The high hormone levels in the whole animal were observed in July and October, coincident with the main spawning seasons.
• 3.3. The levels of progesterone in gonad extracts also show a maximum in summer (July).
• 4.4. The patterns of the progesterone levels in males and females throughout the annual reproductive cycle are similar.
• 5.5. These data are discussed in relation to the role of progesterone in the regulation of sex-specific processes, particularly gametogenesis.

     

Purification and characterization of elastase from the pyloric caeca of rainbow trout (Oncorhynchus mykiss)

• 1.1. An elastase-like enzyme was purified from the pyloric caeca of rainbow trout by hydrophobic interaction, cation exchange and gel-filtration chromatography.
• 2.2. The approximate molecular weight of the elastase was 27 kDa and the isoelectric point was remarkably basic.
• 3.3. The pH optimum of this enzyme was 8.0, when assayed with Succinyl-Ala-Ala-Ala-p-Nitroanilide.
• 4.4. When assayed with Succinyl-Ala-Ala-Ala-p-Nitroanilide, the enzyme activity had a temperature optimum of 45°C, and the enzyme was stable up to this temperature.
• 5.5. The trout elastase exhibited a higher specific activity than porcine elastase against Succinyl-Ala-Ala-Ala-p-Nitroanilide and elastin-orcein.
• 6.6. The trout elastase was inhibited by elastatinal, PMSF, TPCK, SBTI and Bowman-Birk inhibitor.

     

Activities of hexokinase,phosphofructokinase and pyruvate kinase in the body wall,pyloric caeca and tube feet of Asterias vulgaris: Evidence of body wall as a major source of glycolytic activity

• 1.1. The activities of hexokinase (HK) and pyruvate kinase (PK) were significantly higher than the activity of phosphofructokinase (PFK) in the body wall, pyloric caeca and tube feet.
• 2.2. When expressed as a function of wet weight, the specific activity of HK was highest in the pyloric caeca. When expressed as a function of cytosolic protein, the specific activity of HK was highest in the body wall.
• 3.3. Specific activities PFK and PK, expressed as functions of cytosolic protein, were highest in the tube feet. These enzyme activities should reflect the high energetic requirements of the tube feet.
• 4.4. Highest total activity of PFK was found in the body wall. These results support the conclusion that the body wall is a metabolically active organ and that the energetic requirement of the body wall is a significant component of the energetic requirements of the organism.

     

Protein digestion and ion concentrations in rainbow trout (Salmo gairdnerii Rich.) digestive tract in sea- and fresh water

• 1.1. Rainbow trout maintained in fresh water or Actapted to sea-water for 24 hr were fed casein-based dry diet. After feeding, fish were kept in fresh water (FW) or transferred to artificial sea-water (SW) and sacrificed after 10 or 20 hr.
• 2.2. The digestive tract was separated into five parts: stomach, pyloric caeca region, middle intestine and two equal lengths of rectum.
• 3.3. The content of these parts was analysed for ions Na⁺, K⁺, Cl⁻, Mg²⁺ and for free, peptide and total amino acids.
• 4.4. In the fish stomach all ions, with the exception of Ca²⁺, indicate drinking of sea-water. In the pyloric caeca region Na⁺ appears to be efficiently absorbed in SW fish but influxed in FW fish. In the rectum of SW fish K⁺ appears to be reabsorbed but Na⁺ concentrated in faeces.
• 5.5. Free amino acid concentrations were always higher in gut lumen of SW than in FW fish in respect to time after feeding and portion of intestinal content. Free amino acids constitute at most 7.4–8.7% of total amino acids in the content of pyloric caeca region.
• 6.6. Peptide amino acids, being mostly di-, tri- and tetra-peptides, increased in stomach content from 14.7 to 28.4% of the total, from 6 to 10 hr after a meal in SW fish. Peptide amino acids constituted 80.3–89.0% of total amino acids in intestinal content of the pyloric caeca region. These peptide portions decreased in the mid-intestine (47.5–52.5%) and increased again in the rectum (73.6–76.0%).
• 7.7. It was concluded that in rainbow trout fed in both sea- or fresh water, ion concentrations do not seem to interfere with protein digestion and nutrient absorption in alimentary tract.

     

Food deprivation induces differential changes in contents and microstructures of digestive tract and appendages in bluegill fish,Lepomis macrochirus

• 1.1. The digestive tract was compared with the tract appendages (caeca) in bluegill fish, Lepomis macrochirus in their response to short and long term food deprivation.
• 2.2. Fasting for 7 days resulted in 80% reduction of food content in the main tract, but only 40% reduction in appendages (caeca).
• 3.3. The intestine exhibited two different patterns of food distribution under fed and food deprived conditions.
• 4.4. The histopathological impact of starvation was more prominent on the intestine than on caeca.
• 5.5. These results suggest that digestive tract and appendages concommitantly conserve food during food scarcity, but appendages may offer advantages in retaining food longer, and in their greater resistance to starvation-induced effects.

     

Protease,amylase and lipase activities in the midgut and hindgut of the cricket,Gryllus rubens and mole cricket,Scapteriscus acletus

• 1.1. Midgut is the major source of protease, amylase and lipase in a cricket, Gryllus rubens and in a mole cricket, Scapteriscus actetus.
• 2.2. Hindgut makes a significant contribution, and possibly even the major contribution, to digestion in both crickets, with enzyme activities from 20% (amylase and lipase) to 30% (protease) of midgut level, and a pH favorable to action of all three.
• 3.3. Ingested food helps regulate digestive enzyme levels, and crickets starved for 5 days had only 50–60% of normal levels of enzyme activity.

     

The effect of salinity on coelomic fluid osmolyte concentration and intracellular water content in Luidia clathrata (Say) (Echinodermata: Asteroidea)

• 1.1. The concentrations (mM) of osmolytes in the coelomic fluid of Luidia clathrata kept at 25‰S seawater (control individuals) were: 345, Na⁺; 10, K⁺; 10, Ca²⁺; 44, Mg²⁺; 387, Cl⁻; 0.67, amino acids; 0.09, NH₄⁺.
• 2.2. When individuals were transferred from 25‰S to 15‰S or 35‰S, the concentrations of inorganic ions in the coelomic fluid usually equilibrated within 24hr and became the same as those in the medium.
• 3.3. The intracellular water content (g intracellular H₂O/g solute-free dry tissue) of the pyloric caeca and tube feet of control individuals throughout the experiment was 2.13 and 5.40, respectively.
• 4.4. In tissues of individuals transferred to 15‰S, the intracellular water content increased by an average 50% in 12 hr but returned to 19% above control levels during 1 week.
• 5.5. In tissues of individuals transferred to 35‰S, the intracellular water content decreased by an average 17% in 12 hr and did not change during 1 week.
• 6.6. Luidia clathrata is an osmoconformer and partial cell volume regulator within the seasonal salinity range it encounters.

     

Lipid composition of Calanus finmarchicus from the north sea and the arctic. A comparative study

• 1.1. Females, copepodid stages V and IV of Calanus finmarchicus were collected in Fram Strait area of the Arctic and in the northern North Sea to compare their lipid composition.
• 2.2. For the comparison only copepods were considered which contained more than 8% of 18:4 fatty acid and high amounts of wax esters to exclude seasonal and spatial variabilities and different reproductive status of females.
• 3.3. Animals are heavier in the Fram Strait area than in the North Sea with similar lipid proportion of dry weight and wax ester proportion of total lipid.
• 4.4. Only some statistical significant differences exist between the fatty acid and alcohol compositions. The levels of 16:0 acid and alcohol and of 22:1 alcohol are higher and of 20:1 acid and alcohol are lower in the North Sea than in the Arctic.

     

Occurrence of d-alanine in the eggs and the developing embryo of the sea urchin Paracentrotus lividus

• 1.1. d-Alanine has been found in appreciable amounts in the eggs and embryos of the sea urchin Paracentrotus lividus.
• 2.2. The content of d-alanine, expressed as pmol/egg or embryo, is 1.32 in the egg, 0.81 in the blastula, 0.54 in the gastrula and 0.60 in the pluteus.
• 3.3. The percentage of d-alanine with respect to the total alanine (d + l) decreases during embryonic development.
• 4.4. d-Amino acid oxidase, d-alanine transaminase and d-alanine racemase activities were found neither in eggs nor in embryos.
• 5.5. Therefore, it does not appear likely that d-alanine is subject to oxidative metabolism.
• 6.6. The decrease in this d-amino acid during development may be due to its utilization in the synthesis of a more complex molecule.

     

A novel pigment protein in the ovary of echinothurid sea urchins,Asthenosoma ijimai and Araeosoma owstoni

• 1.1. A protein conjugated with a pigment, which showed a peak of absorbance at 385 nm, was identified and partially purified from the ovary of Asthenosoma ijimai and Araeosoma owstoni by butanol extraction, gel filtration, ion-exchange chromatography and adsorption chromatography. This protein was observed only in ovaries, but not in testes.
• 2.2. This protein of A. ijimai showed a molecular weight of 600 kDa on gel filtration. The isoelectric point of the protein was 4.7.
• 3.3. The possible presence of this protein was examined by gel filtration chromatography in the ovaries of 11 other species of sea urchins, Glyptocidaris crenularis, Diadema setosum, Temnopleurus hardwicki, Toxopneustes pileolus, Pseudocentrotus depressus, Hemicentrotus pulcherrimus, Strongylocentrotus intermedius, S. nudus, Echinostrephus aciculatus, Anthocidaris crassispina, Echinometra mathaei and Echinocardium cordatum. However, it was not detected.

     

Adaptation of rainbow trout (Salmo gairdnerii) to sea water: Changes in calcitonin levels

• 1.1. The calcitonin content of the ultimobranchial body (UBB) and plasma levels of calcitonin, calcium and phosphate were measured in rainbow trout (Salmo gairdnerii) following their transfer from fresh to sea water.
• 2.2. The plasma calcium level remained unchanged throughout the experiment while the UBB calcitonin content, plasma calcitonin and plasma phosphate rose significantly during the hours immediately following transfer.
• 3.3. The levels of all three subsequently fall so that, 8–15 days later, a new equilibrium was established with lower than control (fresh water) levels of UBB calcitonin, plasma calcitonin and plasma phosphate.
• 4.4. It would appear, from these data, that calcitonin plays some part in the endocrine regulation of sea water transfer.

     

Comparative study of proteolytic enzymes in the digestive tracts of the european sea bass and hybrid striped bass reared in freshwater

• 1.1. A comparative study of the proteolytic activity in four different sections of the digestive tracts of the European sea bass (Dicentrarchus labrax) and hybrid striped bass (Morone chrysops × M. saxatilis) reared in freshwater revealed minor differences between these fish.
• 2.2. Tryptic activity plays a major role in the proteolytic process in both fish.
• 3.3. The activity of seven intestinal proteolytic enzymes was detected utilizing a combination of specific substrates and inhibitors.
• 4.4. High levels of proteolytic activity were detected in both the proximal and distal sections of the fish intestine at a high pH range (9–10).
• 5.5. In situ monitoring of pH levels revealed a lower pH level in the intestinal proximal section of hybrid striped bass compared with the distal section.
• 6.6. In contrast, higher pH levels were detected at the proximal compared with the distal sections of D. labrax intestine.

     

The biochemical and energetic composition of somatic body components of echinoderms from the northern Gulf of Mexico

• 1.1. The biochemical and energetic compositions of the somatic body components of seven species of asteroids, one ophiuroid, and four echinoids from the northern Gulf of Mexico (30–95 m depth) were ascertained.
• 2.2. Levels of ash were high (68.5–90.8% dry wt) in all body-wall tissues, with the exception of the asteroid Echinaster modestus (51.6% dry wt). Levels of ash were low in the pyloric cecae (nutrient storage organ) of asteroids (4.6–30.8% dry wt).
• 3.3. Levels of lipid (8.1–34.5% dry wt), soluble protein (15.9–28.7% dry wt), and insoluble protein (18.1–48.6%, dry wt) were high in the pyloric cecae of all asteroids, but generally low in ophiuroid and echinoid body-wall tissues. High protein levels (28.5–44.5% dry wt) in the body-wall of the asteroids Echinaster modestus and Anthenoides pierceisuggest it may play a role in nutrient storage.
• 4.4. All somatic tissues contained low levels of carbohydrate (0.2–1.4% dry wt).
• 5.5. Levels of energy in pyloric cecal tissues (12.99–26.05 kJ/g dry wt) were 4–8 times higher than in echinoderm body-wall tissues (2.92–11.91 kJ/g dry wt).
• 6.6. The biochemical and energetic compositions of echinoderms from the northern Gulf of Mexico are similar to those of species from other latitudes and depths.

     

Novel tetraamines,pentaamines and hexaamines in sea urchin,sea cucumber,sea squirt and bivalves

• 1.1. Polyamines were extracted from the guts and ovaries of the sea urchin Anthocidoris crassispina, and the guts and flesh of the sea cucumber Stichopus japonicus and the sea squirt Halocynthia roretzi, the oyster Crassostrea gigas and the short-necked clam Tapes philippinarum, and analyzed by ion-exchange high-performance liquid chromatography and gas chromatography-mass spectrometry.
• 2.2. Norspermidine and norspermine as well as putrescine, cadaverine, spermidine, spermine and agmatine were the ubiquitous polyamines in these invertebrates. These results suggest the widespread distribution of norspermidine and norspermine in invertebrates.
• 3.3. Thermopentamine, thermohexamine and homothermohexamine were found in the sea urchin. This in the first report on the occurence of thermopentamine and hexaamine in invertebrates.
• 4.4. Homospermidine, canavalmine, aminopropylhomospermidine, homospermine, caldopentamine, homocaldopentamine and aminopropylcanavalmine were found in the sea cucumber. Homospermidine, aminopropylhomospermidine and homospermine were found in the squirt. This is the first report on the occurence of canavalmine, aminopropylhomospermidine, homospermine, homocaldopentamine and aminopropylcanavalmine in invertebrates.

     

Absorption and blood clearance of labelled carotenoids ([14C]astaxanthin, [3H]Canthaxanthin and [3H]zeaxanthin) in mature female rainbow trout (Oncorhynchus mykiss)

• 1.1. Using one force-fed meal, eight mature female rainbow trout received [¹⁴C]astaxanthin ([¹⁴C]Ax) with [³H]canthaxanthin ([³H]Cx; N = 3) or with [³H]zeaxanthin ([³H]Zx; N = 5).
• 2.2. Approximately 200 μl of blood were collected via caudal puncture every 24 hr for 4 days. After 96 hr, the fish were killed and pyloric caeca (P.C.) from the duodenal intestine (D.I.) section, ileal intestine (I.I.), and posterior intestine (P.I.) were dissected out.
• 3.3. In the blood, Ax levels were higher than Cx followed by Zx levels.
• 4.4. This corresponds to their respective absorption by the trout as was confirmed by their relative concentrations in P.C., I.I. and P.I.
• 5.5. However, blood clearance was similar for all three compounds. [¹⁴C]Phoenicoxanthin ([¹⁴C]Px) was detected as a reduced metabolite of [¹⁴C]Ax in all gut sections.

     

Absorption of glucose,glycine and palmitic acid by isolated midgut and hindgut from crickets

• 1.1. In vitro experiments indicated that midgut and hindgut anterior to the Malpighian tubules are important in absorption and processing of products of digestion in crickets.
• 2.2. Isolated hindguts from crickets (Gryllus assimilis, G. rubens and Scapteriscus acletus) absorbed and released into the incubation medium 20–30% of a load of [¹⁴C]glucose and 29–31% of a load of[¹⁴C]glycine.
• 3.3. Isolated midguts from the same crickets absorbed and released into the incubation medium 30–50% of the glucose and 43–52% of the glycine load.
• 4.4. Radiolabelled palmitate was absorbed into epithelial cells of isolated mid- and hindguts, but little was transported and released into the incubation medium.

     

Radioimmunological quantification of C21, C19 and C18 steroids in the gonads of Locusta migratoria migratorioides R. and F.

• 1.1. Levels of progesterone, pregnenolone, testosterone, 5α-dihydrotestosterone, estrone and estradiol were measured by radioimmunoassay in purified gonadal extracts of larval and adult male and female Locusta migratoria.
• 2.2. The average steroid contents varied between less than 1 ng to more than 160 ng/g tissue.
• 3.3. Young adults were treated with precocene or ketoconazole in an attempt to influence the steroid contents in gonads.
• 4.4. Ketoconazole treatment had no effect on the steroid contents in gonads whereas precocene treatment resulted in higher contents of androgens.