Sterols from two marine sedimentary annelids

• 1.1. The sterol mixtures of two marine sedentary annelids, Chaetopterus variopedatus and Spirographis spallanzani (Phylum Annelida, class Polychaeta) were fractionated by argentation chromatography and were analyzed by combined gas chromatography-mass spectrometry, capillary GLC and coinjection with standards.
• 2.2. C. variopedatus and S. spallanzani contain Δ⁵-sterols and cholesterol is the major component of the sterol mixtures. In addition to the Δ⁵-sterols C. variopedatus also contains five ring saturated sterols, cholestanol being the principal stanol present.

     

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.

     

Δ5,7Sterols from the sponges Ircinia pipetta and Dysidea avara identification of cholesta-5,7,24-trien-3B-OL

• 1.1. Δ^5,7-sterols have been isolated as pure compounds from the marine sponges Ircinia pipetta (Dictyoceratida:Thorectidae) and Dysidea avara (Dictyoceratida:Dysideidae) by reverse phase HPLC and analyzed by GLC, u.v., mass spectrometry and ¹H-NMR.
• 2.2. Ircinia pipetta and D. avara have rather similar sterol compositions and contain predominantly Δ^5,7-sterols, accompaned by Δ⁵-sterols. Ergosterol, cholesta-5,7-dien-3β-ol and 24-ethylcholesta-5,7-dien-3β-ol are the major sterols in I. pipetta, while D. avara contains in addition to these three sterols, (24Z)-24-ethylcholesta-5,7,24(28)-trien-3β-ol as the fourth major sterol.
• 3.3. Cholesta-5,7,24-trien-3β-ol which previously was not isolated from a marine organism is also present.

     

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 sterol constituents and Δ5,7-sterol content of some bivalve molluscs

• 1.1. The bivalve molluscs Cerastoderma edula, Chlamys opercularis, Ensis soliqua, Modiolus modiolus, Mya arenaria, Mytilus edulis and Pecten maximus contained mixtures of C₂₆-, C₂₇-, C₂₈- and C₂₉-sterols. Cholesterol, 24-methylcholesta-5,22-dien-3β-ol and 24-methylene-cholesterol were the major sterols.
• 2.2. The sterols of Cerastoderma edula, Mya arenaria and Mytilus edulis contained 6–16% of cholesta-5,24-dien-3β-ol.
• 3.3. All the molluscs contained Δ^5,7-sterols in amounts ranging from 2 to 21% of the total sterols.
• 4.4. Cholesta-5,7-dien-3β-ol and 24-methylcholesta-5,7,22-trien-3β-ol were identified in Mytilus edulis. 25-Norcholesta-5,7,22-trien-3β-ol was detected in Modiolus modiolus.

     

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 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.

     

Changes in the phospholipid composition and in fatty acids of phosphatidylcholine and phosphatidylethanolamine of various tissues of the developing tadpole of Agalychnis dacnicolor

• 1.1. Lipid changes occur in the developing tadpole of A. dacnicolor. The phosphatidylcholine content of liver and tail decrease during metamorphosis.
• 2.2. In liver, the fatty acids of phosphatidylcholine and phosphatidylethanolamine become more unsaturated.
• 3.3. In skin, phosphatidylcholine becomes more unsaturated and phosphatidylethanolamine becomes more saturated.
• 4.4. In tail, phosphatidylcholine becomes more saturated and phosphatidylethanolamine shows no change.
• 5.5. Triglycerides become more unsaturated in skin but become more saturated in tail.

     

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.

     

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.

     

Comparative study of the endemic freshwater fauna of lake baikal—I. Phospholipid and fatty acid composition of two mollusc species,Baicalia oviformus and Benedictia baicalensis

• 1.1. Lipid and phospholipid compositions of endemic freshwater molluscs belonging to the class Gastropoda, Baicalia oviformus and Benedictia baicalensis, were studied.
• 2.2. The fatty acids composition of total lipids, neutral, glyco- and phospholipid fraction was investigated by capillary gas chromatography-mass spectrometry.
• 3.3. Ninety-five fatty acids were identified: 23 saturated (both iso- and anteiso-), 28 monoenoic, 14 dienoic and 30 polyenoic.
• 4.4. High percentage of the two main acids, 18:4 and 18:4(n-3) in phospholipid and glycolipid fractions were identified.
• 5.5. A number of unusual polyunsaturated fatty acids, such as 19:4, 18:5(n-3), 24:4(n-6), 24:5(n-6), 24:6(n-3), and furanoid acids, were found.

     

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.

     

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.

     

Metabolic energy of intact honey bee colonies

• 1.1. In late winter, oxygen consumption of honey bee (Apis mellifera L.) clusters showed marked 24-hr periodicity, even when held under constant temperature conditions.
• 2.2. Minimal rates of metabolism (as low as 3.4 w kg ⁻¹) were usually reached at night (ca. 0500 hr), and maximum rates (as high as 33.5 w kg⁻¹) in midday (ca. 1400 hr).
• 3.3. Colonies with brood showed less excursion in daily metabolic rate, by maintaining higher night-time levels.
• 4.4. There is a pronounced decrease in metabolic rate for the intact cluster of 9480–23,394 bees from the rates reported for individuals or small groups of bees.

     

Stearoyl-CoA desaturase activity in primary culture of chicken hepatocytes. influence of insulin,glucocorticoid, fatty acids and cordycepin

• 1.1. Stearoyl-CoA desaturase (Δ9-desaturase) activity was measured in chicken primary hepatocytes, as a function of time in culture.
• 2.2. When using fasted donor animals, the desaturase activity was low at the beginning of culture and then increased steadily to a maximum value between 30 and 70 hr of culture. When hepatocyte cultures were prepared from fed animals, enzyme activity was high at the beginning of culture and maintained thereafter at similar values to those obtained in cultured hepatocytes from fasted animals after 30 hr of culture.
• 3.3. Insulin significantly enhanced enzyme activity when added to the culture medium at a 10⁻⁹M concentration, and a small stimulating effect was also observed with 10⁻⁶M dexamethasone.
• 4.4. Linoleic acid (0.5 mM) added to the culture medium as albuminic complex partly inhibited Δ9-desaturase activity.
• 5.5. Cordycepin (3' deoxyadenosine) decreased enzyme activity when present at a 3 μg/ml concentration in the culture medium.
• 6.6. Taken together, the induction of enzyme activity in culture, its impairment by cordycepin and response to insulin and linoleic acid strongly suggest that synthesis and translation of the Δ9-desaturase mRNA occur in chicken hepatocytes in primary culture, and that this cellular model may be a useful tool for further studies on Δ9-desaturase regulatory mechanisms.

     

Effect of inorganic phosphate on synthesis of 5-phosphoribosyl-1-pyrophosphate in cultured plant cells

• 1.1. Inorganic phosphate (Pi) was absorbed rapidly by suspension-cultured cells of Catharanthus roseus which had previously been cultured in Pi-free Murashige Skoog medium.
• 2.2. The intracellular levels of ATP, ADP and 5-phosphoribosyl-l-pyrophosphate (PRPP) increased markedly during the 24 hr which followed the addition of Pi (1.25mM).
• 3.3. Availability of PRPP in vivo, estimated by the measurement of nucleotide synthesis from [8-¹⁴C]adenine, was also increased by addition of Pi.
• 4.4. Only a 20% increase in the maximum catalytic activity of PRPP synthetase was observed in extracts of cells, prepared 24 hr after addition of Pi.
• 5.5. In contrast to results for mammalian PRPP synthetase, the activity of PRPP synthetase, partially purified from Catharanthus roseus, was inhibited by concentration of Pi greater than 5mM.
• 6.6. The mechanisms involved in the increased availability of PRPP and the synthesis of adenine nucleotides in the plant cells cultured in Pi-containing medium are discussed.

     

Sterols from black sea invertebrates—I. Sterols from Scyphozoa and Anthozoa (Coelenterata)

• 1.1. Rhizostoma pulmo, Aurelia aurita and Actinia equina, the most widespread representatives of Coelenterata in Black Sea have been analysed and the occurrence of 20 sterols has been found.
• 2.2. Dinosterol and demethyldinosterol as well as a number of short side chain sterols have been found in Scyphozoa for the first time.
• 3.3. The occurrence of coprostanol in marine invertebrates has been shown for the first time.
• 4.4. Five groups of sterol esters were found, containing fatty acids with different polarity.

     

Influence of dietary sources of fat on lipid synthesis in mink (Mustela vison) mammary tissue

• 1.1. The fatty acid composition of the triglyceride fraction of mink milk sampled during mid-lactation (day 28 post partum) from two nursing mink was compared to that of plasma samples and to the fatty acid composition of the feed rations used.
• 2.2. Chemical analysis of the triglyceride composition of mink milk demonstrated only minute concentrations of fatty acids with a chain length below C₁₄.
• 3.3. The saturated C_16:0- and C_18:0-unit fatty acids in mink milk made up for 24–40% of the total amount of fatty acids extracted, the remainder being represented by mono and polyunsaturated long-chain (C₁₆-C₂₄) fatty acids.
• 4.4. Preliminary in vitro experiments proved the incorporation of¹⁴C-labelled glucose, acetate or palmitate into triacylglycerols in cultures of mink mammary tissue to be linear for at least 2 hr.
• 5.5. The in vitro capacity for de novo fatty acid synthesis in mink mammary tissue using 14C-labelled glucose or acetate was low, i.e. ranging from 0.096–0.109 nmol/g (fresh tissue)/min, and amounted to only about 5% of that obtained in the case of [¹⁴C]palmitic acid incubation.
• 6.6. Following ¹⁴C-labeIled acetic or palmitic acid incubation of mink mammary tissue neither desaturation nor chain elongation was observed.
• 7.7. In response to long-term feeding on rations with two different sources of animal fat (F = fish oil or L = lard) the influence of compositional changes in dietary neutral lipids on the fatty acid composition of the lipids of mink milk is discussed.

     

The sterols of crustaceans: Decapods (Sub-order macrura)

• 1.1. The effects of environmental depth, geographical location, sex and seasonal changes have been studied on the sterol composition of closely related pelagic decapods.
• 2.2. In addition the sterol composition of the adult bodies have been compared with that of the eggs and the hepatopancreas.
• 3.3. The results indicated a pronounced uniformity of sterol requirements in these animals with cholesterol being easily the major structural sterol.