Collagenaceous,thiol-containing proteins of cnidarian nematocysts: A comparison of the chemistry and protein distribution patterns in two types of cnidae

• 1.1. Nematocyst structural proteins (NSP) from the sea anemones Aiptasia pallida and Metridium senile and the siphonophore Physalia physalis are primarily low molecular weight collagens linked by disulfide bonds.
• 2.2. NSP patterns resolved by SDS-PAGE revealed a common, major collagen species (40 kDa) in each nematocyst type, together with other collagens and non-thiol-containing proteins.
• 3.3. For each cnidarian, NSP glycosylation profiles were significantly different.
• 4.4. Monoclonal antibodies against Aiptasia NSP demonstrated a differential distribution between capsule wall and thread.
• 5.5. NSP differences would account for the diversity of morphologic and functional types.

     

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.

     

Morphological and physiological adaptations in the marginal sphincter of anemone Phymactis clematis,dana 1849 from different environments

• 1.1. We studied the morphology and contractile properties in marginal sphincters isolated from anemones from different environments.
• 2.2. Sphincters from specimens from protected areas are ovoid or roughly square shape. Oval sphincters have increased number of mesogloeal branches and the main axis is thickened. Roughly square sphincters have irregular borders, mesogloeal axes of uniform thickness and homogeneous branching.
• 3.3. Specimens from exposed areas have sphincters with an ovoid shape and dichotomous branching.
• 4.4. Sphincters of specimens from partially protected areas show transition forms.
• 5.5. Under stimulation with KCl at different concentrations, sphincters of anemones from exposed environments contract faster and develop higher isometric forces than muscles isolated from specimens of protected areas.
• 6.6. It was concluded that sphincters of anemones from different environments have a morphology and a physiological response adapted to the milieu.

     

Sterol composition of two actiniaria

• 1.1. The sterol composition of Condylactis aurantiaca and Cereus pedunculatus (phylum Coelenterata, class Anthozoa, order Actiniaria) was investigated by silver nitrate-silica gel column chromatography, combined gas chromatography-mass spectrometry and NMR.
• 2.2. Sea anemones contained Δ³-sterols accompanied by small amounts of Δ^5.7-sterols and ring saturated sterols.
• 3.3. Sterols with 27 carbon atoms are predominant and cholesterol is the principal sterol, followed by 24-methylenecholesterol.
• 4.4. A 4-methyl ring saturated sterol, identified as 4,24-dimethyl-5α-cholest-24(28)-en-3β-ol, occurs in small amount in Actiniaria, accompanied by the corresponding 4-demethylstanol.

     

Multiplicity of dog kidney high-Km aldose reductase and conversion mechanism into aldose reductase

• 1.1. High-K_m, aldose reductase purified from dog kidney inner medulla was easily converted into aldose reductase by incubation in the neutral buffer solution.
• 2.2. High-K_m, aldose reductase was found to be in multiple forms, and was separated into three kinds of species designated as a-, b- and c-forms by HPLC.
• 3.3. The a-form observed as a single peak by HPLC was assumed to be present in three forms (al-, a2- and a3-forms), one was aldose reductase (a 1-form) and the others were the precursors of aldose reductase (a2- and a3-form).
• 4.4. The b-form was rapidly converted into the a3-form, followed slowly by the a2-form and finally into the a 1-form.
• 5.5. The c-form was either directly converted into the al-form, or indirectly into the a2-form followed by the al-form.
• 6.6. Four kinds of species (a2-, a3-, b- and c-forms) of high-Ap, aldose reductase were finally converted into aldose reductase (al-form).

     

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.

     

Phosphonomonoesterase activity in Metridium senile L.

• 1.1. An esterase which hydrolyzes 4-nitrophenyl(phenyl)phosphonic acid (4-NPPP) was purified from M. senile (sea anemone).
• 2.2. The enzyme showed no 5′-nucleotide phosphodiesterase activity with 5′-(4-nitrophenyl) TMP or phosphomonoesterase activity with 4-nitrophenylphosphate.
• 3.3. Addition of excess Zn²⁺ restored activity after inactivation by EDTA.
• 4.4. Thiol reagents and phenylmenthanesulfonylfluoride did not inactivate, whereas, dithiothreitol inactivated.
• 5.5. Aminoethylphosphonic acid (AEP) was a competitive inhibitor of 4-NPPP indicating possible activity with phosphonomonoesters of AEP.

     

Identification and estimation of dopamine released from the anterior byssus retractor muscle of Mytilus californianus in response to nerve stimulation

• 1.1. Small quantities of sea water were recyclically perfused over the surface of paired anterior byssus retractor muscles of Mytilus californianus.
• 2.2. Dopamine was identified in the perfusate by thin-layer chromatography.
• 3.3. Stimulation of the pedal ganglion caused the dopamine content of the perfusate to increase.
• 4.4. A significant increment of release of dopamine was detected at stimulation frequencies above 3 Hz and increased progressively with increase in stimulation frequency.
• 5.5. The possibility of a role for dopamine as a relaxing or inhibitory neurotransmitter in Mytilus is considered in relation to the present and related evidence and to the actions of 5-HT, the probable relaxing transmitter.

     

The carotenoids of eggs of wild and farmed cod (Gadus morhua)

• 1.1. Eggs of wild cod, and of farmed cod fed (a) a diet supplemented with astaxanthin and (b) a diet supplemented with both astaxanthin and canthaxanthin, were analysed with respect to carotenoids.
• 2.2. The total carotenoid contents in eggs were 0.7 ppm for wild cod and 0.5 ppm for farmed cod.
• 3.3. Cod, having white flesh, deposit ketocarotenoids in the eggs, preferably astaxanthin.
• 4.4. Canthaxanthin can replace astaxanthin in the eggs, but astaxanthin appears to be deposited preferentially when both carotenoids are present in the diet.
• 5.5. The isomer distribution of (3S, 3′S):(3R, 3′S, meso):(3R, 3′R) astaxanthin in the eggs reflected the isomer composition of the diet.
• 6.6. Echinenone, 4′-hydroxyechinenone, adonixanthin and zeaxanthin encountered in cod eggs may represent reductive metabolites of canthaxanthin and astaxanthin.

     

A halogenated amino acid-containing sperm activating peptide and its related peptides isolated from the egg jelly of sea urchins,Tripneustes gratilla,Pseudoboletia maculata,Strongylocentrotus nudus,Echinometra mathaei and Heterocentrotus mammillatus

• 1.1. Twenty-eight peptides were isolated from the egg jelly of sea urchins, Tripneustes gratilla, Pseudoboletia maculata, Strongylocentrotus nudus, Echinometra mathaei (type A and B) and Heterocentrotus mammillatus and their amino acid sequences were determined.
• 2.2. Two of the peptides obtained from T. gratilla egg jelly possessed a bromophenylalanine (Br-Phe) residue in their sequences (Gly-(Br-Phe)-Asn-Leu-Asn-Gly-Gly-Gly-Val-Gly and Gly-(Br-Phe)-Asp-Leu-Asn-Gly-Gly-Gly-Val-Gly).
• 3.3. All of the peptides elevated cyclic GMP concentrations in the spermatozoa of the respective sea urchin and caused a shift in the apparent mol. wt of a major sperm protein of the respective sea urchin.
• 4.4. They stimulated respiration rates of the spermatozoa of Hemicentrotus pulcherrimus as well as their own species.
• 5.5. One-half maximal concentrations of the peptides for respiratory stimulation of H. pulcherrimus spermatozoa were between 10⁻¹¹ M and 10⁻⁹ M except a methionine-containing peptide which was about 10⁻⁷ M.

     

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.

     

Olfactory responses to amino acids in marine teleosts

• 1.1. The olfactory responses to amino acids were recorded from the bulb of the red sea bream (Chrysophyrys major) and the conger eel (Conger myriaster).
• 2.2. The threshold concentration for l-glutamine was 10⁻⁷ M in the sea bream and below 10⁻⁸ and 10⁻⁹ M in the conger eel, and it was found that amino acids are good olfactory stimuli in both species.
• 3.3. A comparison of the olfactory spectrum of amino acids of the sea bream with that of each of three species of freshwater fishes revealed a high similarity of spectra.

     

Ostrich fructose-1,6-bisphosphatase: Kinetic characterization of the liver isoenzyme

• 1.1. Purified ostrich (Struthio camelus) liver fructose-1,6-bisphosphatase exhibited an absolute requirement for Mg²⁺.
• 2.2. The enzyme catalyzed the hydrolysis of fructose-1,6-bisphosphate, sedoheptulose-l,7-bisphosphate and ribulose-l,5-bisphosphate.
• 3.3. S_0.5 for substrate was 1.4 μM.
• 4.4. AMP was a potent non-competitive inhibitor with respect to substrate (K_i of 25 μM).
• 5.5. Fructose-2,6-bisphosphate was a potent competitive inhibitor of the enzyme (K_i of 4.8 μM).

     

Catalytic and inhibitory properties of a major molecular form of acetylcholinesterase isolated from Lygus hesperus knight (Hemiptera: Miridae)

• 1.1. The major form of acetylcholinesterase (AChE) from Lygus hesperus demonstrated a greater affinity to selected substrates than unresolved AChE.
• 2.2. The turnover numbers of the native AChE were 7000 min⁻¹ for acetylthiocoline, 4800 for acetyl-(β-methyl) thiocholine, 3000 for propionylthiocholine, and 390 for S-butyrylthiocholine.
• 3.3. Each molecule of the major form had two active sites and each subunit had one active site.
• 4.4. Paraoxon or dichlorvos had a higher affinity to the major AChE form than to the unresolved AChE, resulting in a higher potency for the inhibition.
• 5.5. Some references of comparison are also made with AChE from other animal species.

     

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.

     

Properties of hemocyanins isolated from Amazon river arthropods and molluscs

• 1. Hemocyanins from four organisms inhabiting the Amazon River were isolated and partially characterized.
• 2. Three arthropodan species (Dilocarcinus pagei cristatus, Silviocarcinus pardalinus andMacrobrachium amazonicum) possess hemocyanins whose subunit structure is remarkably simple. Regular and SDS polyacrylamide disc electrophoresis revealed predominantly single bands and no polymorphisms.
• 3. Oxygen-binding experiments showed that the three arthropodan hemocyanins possess large positive Bohr effects and pH dependence in the degree of subunit interaction.
• 4. The hemocyanin of one mollusc,Pila sp., was studied and its subunit size appears to be similar to that of other molluscan hemocyanins, i.e. a polypeptide of mol. wt 400,000. In the hemolymph,Pila hemocyanin probably exists as a mixture of 100 and 124S aggregates.
• 5. The oxygen binding properties of the large molecules ofPila hemocyanin are notable because of their low cooperativity and lack of a strong pH-dependence.

     

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.

     

Purine metabolism in cotyledons and embryonic axes of black gram (Phaseolus mungo L.) Seedlings

• 1.1. The metabolism of purine bases and nucleosides in cotyledons and embryonic axes of black gram (Phaseolus mungo L.) was studied.
• 2.2. A large portion of absorbed [8-¹⁴C]adenine, [8-¹⁴C]guanine and [8-¹⁴C]adenosine was salvaged in nucleotide and nucleic acid synthesis.
• 3.3. Most of the radioactivity of [8-¹⁴C]hypoxanthine and [8-¹⁴C]inosine was incorporated into allantoin and allantoic acid.
• 4.4. Activity of adenine phosphoribosyltransferase in enzyme extracts was much higher than that of hypoxanthme and guanine phosphoribosyltransferase(s).
• 5.5. Apparent activity of adenosine kinase was higher than that of inosine kinase. 6. NAD⁺-dependent xan thine dehydrogenase was detected in both cotyledons and embryonic axes of the seedlings.
• 6.7. The capacity of purine salvage was higher m 24 hr old cotyledons than 24 and 48 hr old embryonic axes. The reverse was observed concerning that of purine degradation.

     

Lipoxygenase of Thermoactinomyces vulgaris,purification and characterization of reaction products

• 1.1. A lipoxygenase preparation was obtained from Thermoactinomyces vulgaris and was purified by affinity chromatography on a linoleyl aminoethyl sepharose column.
• 2.2. Two active fractions were obtained.
• 3.3. The fraction obtained by elution with 100 mM borate buffer pH 9.0 was used in the subsequent work.
• 4.4. Th. vulgaris lipoxygenase oxidized linoleic acid into two products: 13-HPOD and 9-HPOD at a ratio of 44 to 56, respectively.
• 5.5. The identification and characterization of the isomers was done by HPLC, I.R. and mass spectrometry.
• 6.6. When arachidonic acid was used as substrate, 15-HPETE and 15-HETE were found to be the main enzymatic products.

     

In vitro substrate utilization for lipid synthesis in liver explants from hyperthyroid chickens

• 1.1. Indian River male broiler chickens growing from 7 to 28 days of age were fed diets containing 12, 18, 24 and 30% protein + 0 or 1 mg triiodothyronine (T₃)/kg of diet to study energetic costs of lipogenesis and the use of various substrates for in vitro lipogenesis.
• 2.2. De novo lipid and CO₂ production were determined in the presence of [1-¹⁴C]pyruvate, [2-¹⁴q]pyruvate, [3-¹⁴C]pyruvate, [2-¹⁴C]acetate and [U-¹⁴C]alanine.
• 3.3. Oxygen consumption was determined in mitochondrial preparations to estimate the energetic costs in expiants synthesizing lipid.
• 4.4. Radiolabeled CO₂ derived from [1-¹⁴C]pyruvate was used as an estimate of coenzyme A availability in liver expiants. Lipids derived from [2-¹⁴C]pyruvate, [2-¹⁴C]acetate and [U-¹⁴C]alanine estimate relative substrate efficiency.
• 5.5. Labeled CO₂ production from [1-¹⁴C]pyruvate was greatest in that group fed a 12% protein diet and least in the group fed a 30% protein diet.
• 6.6. In addition, T₃ increased CO₂ production from [1-¹⁴C]pyruvate.
• 7.7. The production of ¹⁴CO₂ from the second carbon of pyruvate or acetate was increased by T₃.
• 8.8. The low-protein diet (12% protein) increased (P <0.05) lipogenesis.
• 9.9. Adding T₃ to the diets decreased carbon flux into lipid from all substrates, but increased CO₂ production from all substrates without changing stage 3 and 4 respiration rates in mitochondrial preparations.
• 10.10. These observations imply that coenzyme A availability may have regulated de novo lipogenesis in the present study.
• 11.11. It was also concluded that previously noted effects of T₃ on intermediary metabolism may involve metabolic pathways that do not involve changes in mitochondrial function.