Fatty acid profile of the digestive gland and mantle in the bivalve Macoma balthica

• 1.1. Digestive gland and mantle fatty acids were studied in spring and summer in the bivalve Macoma balthica off the southern coast of Finland. The presence of lipids was also examined histochemically in various clam tissues.
• 2.2. the neutral lipid content of the digestive gland increased ca 4.5-fold during the annual growth period.
• 3.3. Neutral lipid fatty acids of the digestive gland, of which palmitoleic, eicosapentaenoic and palmitic acids were predominant, were clearly distinguished from phospho- and glycolipid fatty acids.
• 4.4. The degree of unsaturation of phospholipid fatty acids was higher in the cold season both in the digestive gland and mantle, mainly due to the titer of eicosapentaenoic acid.

     

Comparative study of the sterol composition of the digestive gland and the gonad of Sepia officinalis L. (mollusca,cephalopoda)

• 1.1. The sterol composition of the digestive gland and the gonad of Sepia officinalis L. was investigated by GC and GC-MS.
• 2.2. The same sterols were recognized in both organs, cholesterol being the major component of the sterol mixtures. However, quantitative differences appeared between the sterol composition of the digestive gland and the gonad.
• 3.3. The sterol mixtures of the digestive gland and the gonad of immature and mature females and males of various origins were compared. Quantitative changes in the sterol composition of the gonad were related to sexual maturity whereas the sterol composition of the digestive gland appeared linked to the diet.

     

Degradation of bacterial lipopolysaccharides by digestive-gland extracts of marine bivalve molluscs

• 1.1. Crude digestive gland extract (DGE) of 5 species of marine bivalve mollusc had glycosidase activity against lipopolysaccharides (LPS) of gram-negative bacteria.
• 2.2. Most of these extracts, after ammonium sulphate precipitation, had higher glycosidase activity than commercial Helix pomatia gut juice.
• 3.3. Inorganic phosphate was also released from LPS by the various DGE but the lipid moiety of LPS appeared to be resistant to attack except by a DGE from Cerastoderma edule, which released small quantities of only non-hydroxylated fatty acids.

     

A simple procedure for evaluating the protein degradation rate in mussel (Mytilus galloprovincialis Lam.) tissues and its application in a study of phenanthrene effects on protein catabolism

• 1.1. An improved, simple method for the evaluation of the protein catabolic rate in the tissues of the lamellibranch mollusc Mytilus galloprovincialis Lam. is presented.
• 2.2. This procedure, which utilizes the technique of the decay curve of a labeled amino acid (¹⁴C-leucine) in the tissues, exploits the capacity of these organisms to rapidly take up soluble compounds from sea-water.
• 3.3. When mussels are exposed to ¹⁴C-leucine in the sea-water, the labeled amino acid is rapidly accumulated into the cell proteins.
• 4.4. A further addition of unlabeled leucine to the sea-water drastically decreases the specific activity of soluble amino acids into the cells, so that the reincorporation of the labeled leucine into the proteins becomes negligible, allowing a correct estimation of the degradation rate of the proteins.
• 5.5. This procedure was utilized to evaluate the effect of phenanthrene on the rate of catabolism of cytosolic proteins in the digestive gland of mussels, and to study the relationship between the protein degradation rate and the activity of lysosomes, which play a well-established role in the catabolism of macromolecules.

     

Selective activation of carcinogenic aromatic amines to bacterial mutagens in the marine musselMytilus gallopro vincialis

• 1.1. The postmitochondrial fraction of the marine mussel Mytilus galloprovincialis digestive gland activates selectively precarcinogenic aromatic amines, but not precarcinogenic benzo(a]pyrene, to Salmonella typhimurium TA 98 mutagens.
• 2.2. This activation potential is NADPH-dependent, is not inducible by exposure to Diesel 2 oil and a polluted environment, and is inhibited by methimazole.
• 3.3. The characteristics of this activation potential are consistent with the recent finding of the presence of FAD-containing-, and lack ofcytochrome P-450 dependent-, monooxygenase activity in Mytilus edulis.
• 4.4. The presence of such selective potential in marine invertebrate(s) may bring new insight into our understanding of the fate and the effects of carcinogens in the marine environment.

     

The digestive enzymes of the pacific brown shrimp Penaeus californiensis.: I—Properties of amylase activity in the digestive tract

• 1.1. Crude extract of the whole digestive tract from the brown shrimp (P. californiensis) was investigated for digestive amylase activity.
• 2.2. Considerable amylase activity was found at pH 6.5–8.0, with optimum pH at around 7.5.
• 3.3. Optimum temperature was found between 30–40°C, similar to amylases from other crustaceans.
• 4.4. Amylase activity was highly halotolerant, having 50% maximum activity at 3 M NaCl.
• 5.5. Maximum amylase activity was found at 0.01 M NaCl.
• 6.6. Amylase activity was partially inhibited by the divalent ions Hg²⁺, Zn²⁺, Cu²⁺ and Cr²⁺.
• 7.7. Mg²⁺ and Ca²⁺ ions seemed to enhance amylase activity.

     

Activities of the three ammonia-forming enzymes in the tissues of the brackish-water bivalve Corbicula japonica

• 1.1. Activities of the three ammonia-forming enzymes, glutamate dehydrogenase, AMP deaminase and serine dehydrase (SerDH), were measured in tissues of gill, digestive diverticula, mantle and foot muscle of the brackish-water bivalve Corbicula japonica.
• 2.2. High levels of SerDH activity were detected in gill and digestive diverticula, while the activity levels of the other two enzymes were low.
• 3.3. The result suggests the significance of SerDH in amino acid degradation of this species.

     

Alteration of the protein composition of bothrops jararaca venom and venom gland by isoproterenol treatment

• 1.1. The protein composition of Bothrops jararaca venom and venom gland was analyzed through SDS-PAGE, after isoproterenol (IPR) treatment.
• 2.2. Some proteins (47, 48, 57 and 72 kDa) were detected in the gland homogenate from the control but not from the IPR-treated samples.
• 3.3. Three proteins (26.5, 44.5 and 53 kDa) were detected in the venom gland from IPR-treated snakes but not from the venom gland from the control.
• 4.4. In the venom samples proteins of 41 and 74 kDa were detected only in the IPR treated samples, while proteins of 17 and 28 kDa were detected only in the control.
• 5.5. The biological activity of the venom did not change with IPR treatment.

     

Ciliary/decarboxylase activities as indicators of PTZ,photoperiod and Ca-ionophore effect on Crassostrea virginica (gmelin)

• 1.1. Lateral ciliary activity and DOPA decarboxylase were measured in the ctenidium of Crassostrea virginica (Gmelin).
• 2.2. Activity of the lateral cilia is dependent upon branchial nerve (Paparo, 1985a,b) and on intracellular calcium homostasis (Baker, 1963; Rassmussen, 1970, 1971; Romero and Wittman, 1971; Blanstein et al., 1978).
• 3.3. PTZ induced lamella morphogenesis in eytosomes with subsequent release of calcium into the cytosol. This cilio-inhibition was enhanced in the presence of additional calcium in the perfusate.
• 4.4. Prolonged exposure to light also induces fully converted membranous eytosomes with subsequent production of a gradual lateral cilio-inhibition. Darkness produces the opposite effect, in that secondary membranous conversions of cytosomes are inhibited.
• 5.5. In the presence of A-23187 (a calcium releasing agent), inhibition of lateral activity is produced, independent of cytosomal conversion.
• 6.6. It is postulated that photic electrical and chemical stimulation of neuronal chromoproteins can lead to release of calcium from sequestered cytosomal stores which triggers a neuro-exocytosis of a neuroinhibitory transmitter, dopamine.

     

Thermal properties for digestive enzymes of a sub-antarctic beetle,hydromedion sparsutum (coleoptera,perimylopidae) compared to those in two thermophilic insects

• 1.1. Proteolytic, lipolytic, amylolytic and cellulolytic activities were studied in adults of the phytophagous beetle, Hydromedion sparsutum, indigenous to the sub-Antarctic island of South Georgia.
• 2.2. Gastric enzyme activities were measured at experimental temperatures of 5–40°C and results were compared with those obtained from two thermophilic insects, Gryllus bimaculatus and Tenebrio molitor.
• 3.3. Protease and lipase activities in Hydromedion were 10–15 times lower than in Gryllus and Tenebrio.
• 4.4. In the temperature range of 5–15°C, α-amylase activity from Hydromedion was only slightly lower than that from Gryllus.
• 5.5. Hydromedion gut homogenates exhibited a distinct cellulolytic activity, even at a low temperature of 5°C.
• 6.6. Cellulolytic activity in the digestive tract of Hydromedion was confirmed by the evolution of ¹⁴CO₂ after consumption of labelled cellulose.
• 7.7. The thermal properties of digestive enzymes agree well with the role of Hydromedion as primary decomposer in its ecosystem.

     

Digestion of protein in different marine species

• 1.1. The digestion proteases in five marine species (Atlantic halibut, Hippoglossus hippoglossus (L); Dover sole, Solea solea (L); turbot, Scophthalmus maximus, (L); European lobster, Hommarus gammaarus (L); and the giant prawn, Penaeus monodon) have been compared by biochemical methods.
• 2.2. The pH profiles for the hydrolysis of casein by extracts from the digestive systems of each species showed different characteristics; extracts from adult halibut, turbot and sole exhibited strong pepsin-like activity; whereas this enzyme was absent in P. monodon and in sole larvae.
• 3.3. Although lobster extracts, from either the hepatopancreas or the stomach, showed peaks at pH values of 5.8 and 2.5, this latter activity did not hydrolyse a specific substrate for pepsin.
• 4.4. Halibut and turbot digestive extracts contained an activity optimal at pH values in the region of 5.0 resembling a cathepsin-like enzyme; an activity which was not evident in the other species under similar experimental conditions.
• 5.5. Although all species possessed trypsin-like activity, the pH profiles of activity in the neutral to alkaline region were unique to each species.
• 6.6. The significance of these results is considered with respect to the anatomical differences in the alimentary systems of these species.

     

IDentification of a microsomal retinoic acid synthase as a microsomal cytochrome P-450-linked monooxygenase system

• 1.1. To characterize an enzyme which metabolizes retinal in liver microsomes, several properties of the enzymatic reaction from retinal to retinoic acid were investigated using rabbit liver microsomes.
• 2.2. The maximum pH of the reaction in the liver microsomes was 7.6.
• 3.3. The K_m and V_max values for all-trans, 9-cis and 13-cis-retinals were determined.
• 4.4. The reaction proceeded in the presence of NADPH and molecular oxygen.
• 5.5. The incorporation of one atom of molecular oxygen into retinal was confirmed by using oxygen-18, showing that the reaction comprised monooxygenation, not dehydrogenation.
• 6.6. The monooxygenase activity was inhibited by carbon monoxide, phenylisocyanide and antiNADPH-cytochrome P-450 reductase IgG, but not by anti-cytochrome b₅ IgG.
• 7.7. The enzymatic activity inhibited by carbon monoxide was photoreversibly restored by light of a wavelength of around 450 nm.
• 8.8. The retinal-induced spectra of liver microsomes with three isomeric retinals were type I spectra.
• 9.9. The microsomal monooxygenase activity induced by phenobarbital or ethanol were more effective than that by 3-methylcholanthrene, clotrimazole or β-naphthoflavone.
• 10.10. These results showed that the monooxygenase reaction from retinal to retinoic acid in liver microsomes is catalyzed by a cytochrome P-450-linked monooxygenase system.

     

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.

     

Stimulation of plasmin activity in cultured human fibroblast cells by Porphyromonas endodontalis

• 1.1. Plasmin activity in the conditioned medium of Gin-1 cells, a human gingival fibroblast cell line, was stimulated by Porphyromonas endodontalis, a putative pathogen of oral submucous abscesses, in a time- and dose-dependent manner.
• 2.2. P. endodontalis stimulated the activity of plasminogen activator in both the conditioned medium and the cell lysate. The plasminogen activator in Gin-1 cells was approx. 50kDa by zymography.
• 3.3. The conditioned medium of Gin-1 cells exposed to P. endodontalis stimulated the conversion of human serum prekallikrein to kallikrein.
• 4.4. These results suggested that P. endodontalis stimulates the plasminogen activator-plasmin system in Gin-1 cells, and that activated plasmin plays a role in the progress of periodontal tissue inflammation.

     

Haematology of the australian eastern quoll,Dasyurus viverrinus

• 1.1. A variety of haematological parameters were determined in adult Dasyurus viverrinus.
• 2.2. Haemoglobin and red cell counts were high with a very low mean cell volume.
• 3.3. Basophils are absent but the eosinophils contain small numbers of basophilic granules which may indicate a dual role for this cell.
• 4.4. “Ring Form” leucocytes are present.
• 5.5. Three types of red cell picture could be identified, some animals showing large numbers of spherocytes, spicule cells, and inclusion bodies.
• 6.6. These cells resemble those found in some inherited human haemolytic anaemias but there was no evidence of haemolysis in the animals.
• 7.7. An alkali resistant haemoglobin component is present.

     

Taurine regulation of Ca2+ uptake and (Ca2+ + Mg2+)-ATPase in developing chick B-cells

• 1.1. The objective of the present study was to determine the effect of age and taurine on chick B cell calcium uptake and membrane (Ca²⁺ + Mg²⁺)-ATPase activity in 1–4-week-old chicks.
• 2.2. The calcium uptake rate decreased with age (P < 0.05) and was further decreased by taurine (P < 0.05).
• 3.3. (Ca²⁺ + Mg²⁺)-ATPase activity increased with age (P < 0.05) and was stimulated by taurine (P < 0.05).
• 4.4. The data demonstrate that the flux of calcium across the B-cell membrane changes during early post-hatch development, and that taurine regulates both the influx and efflux of calcium in chick B-cells.

     

Responses of antioxidants and lipid peroxidation in mussels to oxidative damage exposure

• 1.1. The aim of this work was to evaluate the relationships between free radical scavengers and lipid peroxidation in the common mussel Mytilus edulis.
• 2.2. Mussels were exposed to compounds known for their ability to produce free radicals (carbon tetrachloride, CCl₄) and reactive oxygen species via redox cycling (menadione), and the effects on digestive gland, gills and remaining tissues were studied.
• 3.3. Lipid peroxidation parameters and the status of free radical scavengers (glutathione, vitamins A, E and C) were affected more by exposure to menadione than to CCl₄.
• 4.4. The observed changes in the free radical scavengers content are indicative of a role in detoxication of damaging reactive species.

     

The regulation of glucose 6-phosphate dehydrogenase from Dicentrarchus labrax (bass) liver

• 1.1. Kinetic constant values of the reaction catalyzed by bass liver glucose 6-phosphate dehydrogenase show to be modified between 10 and 40°C.
• 2.2. The Arrhenius plot between 10 and 50°C shows two slopes with different activation energies.
• 3.3. These results suggest a regulation of this enzyme by environmental temperature.
• 4.4. Kinetics of ATP inhibition were examined between pH 6.2 and 7.8: patterns and K_i values obtained are affected by the pH variation.
• 5.5. NADH is an effective inhibitor of bass glucose 6-phosphate dehydrogenase but this enzyme does not show NAD-linked activity.
• 6.6. Kinetics of pyridoxal 5′-phosphate inhibition have indicated the presence of a lysine in the catalytic site for NADP⁺.

     

Effects of membrane-perturbing drugs and noradrenalin on cAMP accumulation and red cell water content in carp (Cyprinus carpio) red cells

• 1.1. Carp red cells were treated with drugs that affect the cell membranes. The water content of the cells and the accumulation of cAMP in the cells were measured in normoxia and in hypoxia using non-stimulated and adrenergically stimulated cells.
• 2.2. WGA, DIDS + CCCP and A23187 increased the water content of nonstimulated normoxic cells.
• 3.3. In hypoxia ouabain and DIDS + CCCP increased the water content but cytochalasin B, NPM, DIDS, CCCP and A23187 + CA²⁺ abolished the hypoxia-induced swelling.
• 4.4. Any membrane perturbation induced some cAMP formation, Sophora and Anquilla lectins being most potent.
• 5.5. Also in adrenergically stimulated cells, membrane perturbation generally increased cAMP formation.
• 6.6. However, cAMP accumulation diminished in cells treated with cytochalasin B, CCCP and DIDS + CCCP.
• 7.7. The adrenergic swelling of carp red cells was reduced in normoxia by DIDS. NPM and CCCP increased the adrenergic swelling in normoxia to hypoxic level.
• 8.8. In hypoxia WGA and Anquilla lectin decreased the swelling.

     

Comparison of U-small nuclear RNA levels in tissues of the silkmoth,Bombyx mori

• 1.1. Tissue-specific abundance of the capped small RNAs in the silkmoth Bombyx mori was compared using preparative immunoprecipitation with anti-trimethylguanosine antibody.
• 2.2. The yields of total capped small RNAs from larval posterior silk gland, 1. early, 2. late in the fifth-instar, and 3. immortal ovarian-derived cells in culture, were determined to be 187, 50 and 218 ng, respectively, per mg of total cellular RNA.
• 3.3. Separation of immunoprecipitated RNAs by polycrylamide gel electrophoresis, followed by densitometric analysis of the bands, allowed the quantitation of individual capped molecules.
• 4.4. This analysis revealed tissue-specific patterns.
• 5.5.|The data indicate that the total abundance of capped small RNAs in Bombyx is highest in rapidly-dividing cells.