Sterol composition of marine bivalves from the genus Macoma

• 1.1. Four members of the genus Macoma: M. Balthica, M. irus, M.;incongrua; and M. contabulata from the Japan Sea were investigated for their sterol composition.
• 2.2. Cholest-5-en-3β-ol was the most abundant sterol in all investigated animals; the other major sterols were common constituents of bivalves.
• 3.3. The observed similarity in sterol composition of the studied clams seems to be an indication of greater influence of ecological than genetic factors on sterol composition.

     

Sterol composition of three marine sponge species from the genus Cinachyrella

• 1.1. The hitherto undescribed sterol compositions of three marine sponge species belonging to the genus Cinachyrella are reported: C. alloclada and C. kükenthali from the Senegalese coast, at two different depths, and C. aff. schulzei from the lagoon of Nouméa, New Caledonia.
• 2.2. Fourteen free sterols have been identified by GC and GC/MS studies, including the 23,24ξ-dimethylcholesta-5,22-dien-3β-ol (10) and the rare 24-norcholesta-5,22-dien-3β-ol (1).
• 3.3. The first compound (10) is reported for the second time in a marine sponge and it was found only in Senegalese sponges collected in shallow waters.
• 4.4. Sterol (10) has been isolated by HPLC and identified by NMR techniques.
• 5.5. Significant amounts of cholest-7-en-3β-ol (7) were also found in the Senegalese sponge species.
• 6.6. Apart from these two compounds, the three sponge sterol compositions are found to be very similar.

     

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.

     

The occurrence of brassicasterol and epibrassicasterol in the chromophycota

• 1.1. Sterols were identified from eight isolates of five species in the Chromophycota that were cultured axenically and harvested in the stationary phase.
• 2.2. Analyses were performed on four strains from the Prymnesiophyceae, two strains from the Cryptophyceae and one from the Bacillariophyceae. Most strains examined contained only one major sterol, 24-methyl-22-dehydrocholesterol.
• 3.3. Analysis by capillary GC, HPLC, and in one instance NMR, showed that the two strains provisionally identified as Isochrysis contained brassicasterol (24β-methyl-22-dehydrocholesterol); whereas, all other species examined contained primarily epibrassicasterol (24α-methyl-22-dehydrocholesterol).
• 4.4. Stigmasterol (24α-ethyl-22-dehydrocholesterol) accompanied epibrassicasterol in Pleurochrysis carterae.
• 5.5. Analyses of C-24 alkyl isomers in these algae may provide useful information concerning their taxonomic placement.
• 6.6. The occurrence of both isomers of 24-methyl-22-dehydrocholesterol in oysters is explained by the occurrence of both isomers among algae which are probably dietary sources for oysters.

     

Steroids from aquatic organisms—XII. Sterols from the antarctic sponge Homaxinella balfourensis (Ridley and Dendy)

• 1.1. The sterol composition of the sponge Homaxinella balfourensis (Ridley and Dendy) has been analysed and seven components detected.
• 2.2. These were separated by argentic column chromatography and studied by gas chromatography-mass spectrometry and by proton magnetic resonance spectroscopy.
• 3.3. It was established that the components were C₂₇, C₂₈ and C₂₉ fully saturated or side chain unsaturated stanols and colest-5-en-3β-ol as traces.

     

Sterol composition of the “living fossil” crinoid Gymnocrinus richeri

• 1.1. The composition of sterol mixture from the “living fossil” crinoid Gymnocrinus richeri collected off Nouméa (New Caledonia) was investigated.
• 2.2. The free 3β-OH sterol mixture was found to contain 14 components, Δ⁵ and ring saturated stanols, identified by GC-MS.
• 3.3. Cholest-4-en-3-one, cholesta-1, 4-dien-3-one (this latter firstly isolated from a marine source), 5α-8α-epidioxy sterols, and 5α-ergosta-7,22-diene-3β,5,6β-triol were also present, their characterization being accomplished by EI-MS and ¹H-NMR. The methanol extract also contained sterol sulphates, which were identified by GC-MS after solvolysis to remove the sulphate group.

     

The influence of stigmasterol concentration on the growth and lipid composition of wild-type and barium a strains of Paramecium tetraurelia

• 1.1. The ciliary membrane lipid composition and electrophysiology of the behavioral mutant of Paramecium tetraurelia, barium A (d4–592), were previously shown to differ from those of wild-type 51S when both strains were grown in low sterol medium.
• 2.2. In this study, the phospholipid fatty acid composition of the two strains was shown to differ regardless of the level of sterol supplementation or culture age (growth phase).
• 3.3. The ratio of linoleic to γ-linolenic acid, 18:2(9,12)/18:3(6,9,12), was consistently higher in baA compared to wild-type phospholipids, largely because of a dramatic shift in the ratio of these two fatty acids esterified at the 2 position of 1-alkyl-2-acyl-sn-glycero-3-phosphorylcholine (GPC).
• 4.4. These data support the hypothesis that a specific Δ6 fatty-acyl desaturase, which directly desaturates phospholipid and shows a preference for GPC as its substrate, is impaired as a result of the barium A mutation.

     

Effects of Echinostoma trivolvis (Trematoda) infection on neutral lipids,sterols, and carotenoids in Helisoma trivolvis (Gastropoda)

• 1.1. Histochemical, thin layer and gas-liquid chromatographic studies were done on neutral lipids, sterols and carotenes in the digestive gland-gonad (DGG) complex of Helisoma trivolvis infected with Echinostoma trivolvis vs uninfected DGG.
• 2.2. Hitochemical Oil Red O staining showed the presence of neutral lipids in the redial body wall and in the digestive cells of the DGG.
• 3.3. TLC showed that free sterols and triacylglycerols were major neutral lipid fractions along with lesser amounts of steryl esters and free fatty acids in the DGG of both populations. The percentage composition of all neutral lipid fractions was greater in infected than uninfected DGG.
• 4.4. Infected DGG contained more carotenoid fractions than uninfected DGG, but only beta-carotene was identified from both.
• 5.5. GLC studies showed that the major sterol present in snail DGG was cholesterol (about 70%) along with lesser amounts of stigmasterol, campesterol, beta-sitosterol and desmosterol. No clear cut distinction was seen in sterols from infected vs uninfected DGG.

     

Unsaponifiable matter of liver oil of intensively reared sea bass (Dicentrarchus labrax): Sterols and aliphatic alcohols

• 1.1. Sterols and aliphatic alcohols of sea bass (Dicentrarchus labrax) liver oil intensively reared and fed on three different diets were studied, with the aim of verifying any differences due to diets and seasonal variations.
• 2.2. Ten components of the sterol fraction were found; the largest component was cholesterol.
• 3.3. Nineteen linear chain alcohol components were identified: there were between 14 and 32 carbon atoms, mainly saturated; the 28:0 and the 30:0 were the most abundant.
• 4.4. Evident differences were not due to the three diets adopted, but to the seasonal conditions; the quantity of sterols present in the liver decreased in the cold months, in connection with reproduction.

     

Sterol composition of some gorgonians from the Senegalese coast

• 1.1. The sterol composition of nine gorgonians from the Senegalese coast was investigated by capillary GC and GC/MS.
• 2.2. Fourteen sterols were identified with cholesterol, brassicasterol, 22(E)-dehydrocholesterol and 24-methylenecholesterol as major components.

     

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.

     

Chemical cross-links of proteins by using bifunctional reagents

• 1.1. The chemical identification of spatial arrangements of the subunits in oligomeric proteins is exclusively achieved by the analysis of the reaction products of the protein and bifunctional reagents.
• 2.2. Since the pioneer work of Hartman and Wold (Biochemistry6, 2439–2448, 1967) the bifunctional reagent such as bis-imido-esters was first introduced into protein chemistry.
• 3.3. We have listed the non-cleavable and cleavable bis-imido-esters, the N-hydroxy-succinimido-csters and the aryl azides which once photolyzed, become the highly reactive nitrene intermediates.
• 4.4. Different reagents classified as homo- and hetero-bifunctional reagents are also listed.
• 5.5. The advantages and limits of each group as well as their chemical properties are advanced and extensively discussed.

     

The effect of γ-radiation on the NADP-MALIC enzyme from mango fruit,mangifera indica—I. Physico-chemical aspects

• 1.1. Malic enzyme purified from the fruit tissue of Mangifera indica was irradiated in dilute solution and the effect of γ-irradiation was investigated.
• 2.2. The activity of the enzyme decreased exponentially as a function of the applied dose under all conditions investigated. The inactivation yield (Go-value) in neutral solution and in air was 0.069.
• 3.3. The role of the radicals produced by water radiolysis in the inactivation of the enzyme was investigated by using different gas atmospheres and selective free radical-anions. The hydrogen atom and the hydrated electron (reducing species) were found to be important in the enzyme inactivation; as well as the possible destruction of cysteine and tryptophan residues.
• 4.4. The irradiated enzyme appears to adopt a more compact conformation as reflected in a slightly lower M_r, Stokes-radius and diffusion coefficient.
• 5.5. γ-Radiation does not lead to any heterogeneity in the charge and size properties of the enzyme and the pI and the M_r of the subunits were unaffected.
• 6.6. Some differences in the amino acid composition of the non-irradiated and irradiated enzyme were observed but specific amino acid residues were not preferentially destroyed.
• 7.7. These changes were also reflected in the ultraviolet spectrum of the enzyme which shifted to lower values.
• 8.8. The major cause of inactivation seem to be a change in conformation caused by chemical modification of amino acid side chains.

     

Steroid metabolites of the far eastern Holothurian Stichopus japonicus Selenka

• 1.1. Sulphated and etherified sterols were isolated from the far eastern holothurian Stichopus japonicus S. The sterol composition of both fractions was determined using gas-liquid chromatography and mass-spectroscopic methods. The structures of individual sterols were proved on the basis of mass-spectrometry and ¹H-NMR-spectroscopy data.
• 2.2. The structures of 29 sterols were established.
• 3.3. Sterols (22E, 24R)-23,24-dimethyl-5α-cholest-22-en-3β-ol, 23,24-dimethyl-cholesta-5,22-dien-3β-ol, 24-methyl-cholesta-5,24(28)-dien-3β-ol, (24Z)-24-ethyl-cholesta-5,24(28)-dien-3β-ol, 24-nor-cholesta-5,22-dien-3β-ol, 24-ethyl-cholesta-5,25-dien-3β-ol were described for holothurians for the first time.
• 4.4. Δ⁵-sterols were shown to be the main components of the sulphated alcohol fractions (67.61%), while the saturated and Δ⁷-sterols were there in less quantities (14.72 and 9.52%, respectively).
• 5.5. The etherified sterols were represented, mainly, by saturated and Δ⁷-sterols (37.82% and 33.95%, respectively). Δ⁵-sterols were 19%.
• 6.6. The sensitivity of liposomal membranes, containing steroid metabolites of the holothurian St. japonicus (Δ⁷-, sulphated and glycosilated sterols) to the action of endotoxin-stichoposide A, was studied.

     

Hydrolysis of glycol chitin by chitinolytic enzymes

• 1.1. The hydrolysis of glycol chitin preparations by several β-N-acetylglucosaminidases was monitored colorimetrically with the potassium ferriferrocyanide reagent.
• 2.2. Glycol chitin samples from crab and insect sources varied considerably in chemical composition and susceptibility to enzymatic hydrolysis.
• 3.3. Insect endochitinase preferred crab glycol chitin as substrate while hen's egg white lysozyme preferred commercial glycol chitin.
• 4.4. Insect glycol chitin was well hydrolyzed by both enzymes.
• 5.5. Insect exochitinase did not digest glycol chitin.

     

Characteristics of Crassostrea virginica crystalline style chitin digestion

• 1.1. Fundamental chitin digestion characteristics of Crassostrea virginica crystalline style were investigated.
• 2.2. Optimum temperature and pH were 34°C and 4.8. respectively.
• 3.3. The colloidal regenerated chitin (0.56mol/0.5 ml: GlcNAc equivalents) was saturating under all enzyme levels encountered.
• 4.4. There was no evidence of end product inhibition, even after 100 hr incubation.
• 5.5. Calculated K_m for the chitinase complex was 1.19mM when determined using a 30 min assay, but was only 0.70 mM when determined using a 4.6 hr assay.
• 6.6. Both K_m values are lower than reported for similar assays in other molluscs and for most bacteria.
• 7.7. Effect of substrate preparation on the kinetics are discussed.
• 8.8. Eight peaks of chitinase activity were resolved by DEAE-Fractogel ion exchange chromatography.

     

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.

     

The inhibitory effect of tetramethylethylene diamine on water soluble and membrane bound acetylcholinesterase activity

• 1.1. The inhibitory effect of N,N,N′,N′-tetramethylethylene diamine (TEMED) on water soluble (WSAChE) and membrane bound (MBAChE) acetylcholinesterase was investigated.
• 2.2. TEMED (0.5–4.0 mM) reversibly inhibited WSAChE activity (18–62%) and MBAChE (20–61%) in a concentration dependent manner.
• 3.3. The IC₅₀ being about 2.8 mM for WSAChE and 2.6 mM for MBAChE.
• 4.4. Lineweaver-Burk plots indicated that the nature of inhibition is noncompetitive for both water soluble and membrane bound acetylcholinesterase, with K_m values 68 μM and 123 μM respectively.
• 5.5. An Arrhenius plot showed that the transition temperature (TT) is unaffected in the presence of TEMED.
• 6.6. The activation energy was increased below and above TT in the case of WSAChE only.
• 7.7. On the basis of this behaviour of TEMED with AChE. it can be proposed that it can be used as an eluting agent for the bounded AChE to affinity ligand and may have beneficial action on the reactivatability of irreversibly-inhibited AChE due to its structure.
• 8.8. Moreover there is a possibility that it can be used as a therapeutic agent for the treatment of Alzheimer's disease, myasthenia gravia and glaucoma like some other inhibitors of AChE.

     

Deleterious effects of disulfiram on the respiratory electron transport system of liver mitochondria

• 1.1. The mechanism of action of disulfiram on the respiratory electron transport system of the liver mitochondria was studied in vitro.
• 2.2. Disulfiram inhibited the respiration supported by malate-glutamate as well as succinate.
• 3.3. Mitochondrial respiration inhibition was dependent upon alteration of —SH groups.
• 4.4. The inhibitory action of disulfiram might be related to the crosslinking of several proteins of the inner mitochondrial membrane.
• 5.5. The effects described above could be attributed to disulfiram per se and not to the main metabolite diethyldithiocarbamate.