Biochemical and functional characterization of Rapana thomasiana hemocyanin

• 1.1. The hemocyanin (Hc) of the marine gastropod mollusc Rapana thomasiana was collected from animals living on the west coast of the Black Sea and characterized for its biochemical and functional properties.
• 2.2. This Hc is very similar to other gastropod Hcs as far as amino acid composition, general structure and reactivity of the binuclear copper active site are concerned.
• 3.3. Some peculiarities in the dissociation-reassociation pattern are observed in comparison to other gastropod Hcs, in particular with respect to the ability to form sopramolecular aggregates.
• 4.4. Changes in pH disclose a strong reverse Bohr effect. Different R and T states are required to describe the oxygen binding curves at the different pHs.

     

Acetylcholinesterase in the brain of the marine gastropod Murex trunculus L. (Prosobranchia). Isolation and properties

• 1.1. Cholinesterase (ChE) of two types—acetylcholinesterase (AChE, acetylcholine hydrolase, EC 3.1.1.7) and propionylcholinesterase (PrChE, acylcholine hydrolase, EC 3.1.1.8)—was found in the brain of the marine gastropod Murex trunculus L. (Prosobranchia).
• 2.2. PrChE is a soluble enzyme which can be easily extracted by salt solution after freezing-thawing of the untreated brain.
• 3.3. AChE is membrane-bound. It was solubilized by a 0.2% solution of Triton X-100.
• 4.4. Some part of AChE (up to 36%) can spontaneously pass into solution.
• 5.5. The specific activity of AChE in Triton X-100 extracts is 100 ± 10 nmol acetylcholine/mg protein/min.
• 6.6. Enzyme hydrolysis of acetylcholine (ACh), acetylthiocholine (ATCh) and propionylthiocholine (PrTCh) is suppressed by excess of substrate. Michaelis constants (K_m) for their hydrolysis by AChE are 0.33, 0.017 and 0.018 mM, respectively.
• 7.7. Bimolecular rate constants with organophosphorus inhibitors of different structure points to a similarity of the gastropod brain AChE to the typical enzyme of vertebrates in the structure of the active surface.

     

Neurohypophysial hormones as molecular evolutionary tracers: investigations on the sturgeons Acipenser stellatus and Acipenser guldenstadti

• 1.1. Neurohypophysial hormones of two sturgeon species, Acipenser stellatus and Acipenser guldenstadti, have been purified through molecular sieving on Bio-Gel P4 and reverse-phase high pressure liquid chromatography on Nucleosil C18 columns.
• 2.2. Arginine vasotocin has been identified in both species by its retention time in partition chromatography, amino acid composition and, in the case of A. stellatus, by amino acid sequencing.
• 3.3. A second peptide has been purified and could be α-deamidated vasotocin.
• 4.4. Another peptide with oxytocic activity, distinct from the known oxytocin-like peptides, seems to be present in very small amounts.

     

The reproduction strategy of oyster ostrea edulis L. from the biochemical point of view

• 1.1. Influence of the biochemical composition of food (four species of micro-algae and one mixture) on the biochemical composition of gonads and larvae of O. edulis (total protein, lipid, carbohydrate, ash content, neutral and polar lipid class composition, amino acid composition and fatty acid composition of total, neutral and polar lipids) and the size of newly released larvae have been investigated.
• 2.2. Precentage of total lipids and triacylglycerols in gonads depends on that in algae (r = 0.52 and 0.69 accordingly).
• 3.3. Gonads rich in lipids had a higher level of triacylglycerols, phospholipids, polar lipids and a lower value of the ratio phosphatidylethanolamine/phosphatidylcholine (PE/PC) than gonads with a low lipid content.
• 4.4. Amino acid composition of gonads depends on that of food, in this case, essential acids are preferentially accumulated (Asp acid, Ser, Ala, Cys, Tyr and Pro) and two non-essential (Thr and Lys).
• 5.5. Fatty acid composition of total lipids of gonads was rather stable; except for the two essential acids 20:523 and 22:6w3, their percentage depends on that of food r = 0.65 and 0.65 accordingly). Fatty acid composition of neutral lipids was more diverse (in number and degree of variety) as compared to polar lipids.
• 6.6. Larvae released from oysters with gonads rich in lipids had a higher percentage of lipids, triacylglycerols, size and a lower ash percentage and value of ratio PE/PC, as compared to larvae from gonads with low lipid content. Total lipid and triacylglycerol contents in gonads correlate rather well with those in larvae (r = 0.77 and 0.47 accordingly).
• 7.7. Phospholipid class composition of larvae strongly depends on that of gonads. All the correlations are high and positive in character (except for phosphatidylinositol).
• 8.8. Amino acid composition of larvae depends on that of gonads and, as in the case with gonads, the same essential acids are accumulated in the first place.
• 9.9. Fatty acid composition of total lipids of newly released larvae was rather stable and independent on that of gonads except for total polyunsaturated acids (r = 0.70) and 20:5w3 (r = 0.65). Fatty acid composition of neutral lipids was lesser diverse (in number and degree of variation) as compared to polar lipids.

     

Microheterogeneity of late histones in larval stages of sea urchin development

• 1.1. The total histone complement of early plutei were compared with that of intermediate and late larvae of the sea urchin Tetrapygus niger.
• 2.2. Electrophoretic comparison indicates that there are quantitative and qualitative shifts of the five classes throughout late larval development.
• 3.3. The strong similarity in the amino acid composition of total histones isolated from early, intermediate and late plutei indicates that the observed electrophoretic heterogeneity is due to post-translational modifications.

     

Fatty acid composition of five zoantharia from the senegalese coast: Palythoa Dartevellei pax,P. monodi Pax,P. Variabilis duerden,P. Senegalensis pax and their associated zooxanthellae and P. senegambiensis carter and its commensal,the decapoda diogenes ovatus miers

• 1.1. The quantitative and qualitative fatty acid composition of five Palythoa from the Senegalese coast and their associated organisms: Zooxanthellae symbiont or decapoda commensal have been determined by capillary G.C.
• 2.2. The fatty acid compositiion of each associated organism, host and symbiont or commensal, presents enough characteristic differences to think that each of them synthesizes de novo its own fatty acids.
• 3.3. These results suggest to us that the fatty acid composition of Palythoa and of Zooxanthellae might be a better and more useful tool for the taxonomic classification of these two families than sterol composition.

     

Amino acid composition and the protein form of procarboxypeptidase a purified from the pancreas of the sei whale Balaenoptera bolealis

• 1.1. Procarboxypeptidase (W-PCPA) was purified from the pancreas of the sei whale Balaenoptera bolealis.
• 2.2. W-PCPA was obtained as a homogeneous protein in polyacylamide gel disc electrophoresis.
• 3.3. W-PCPA has a molecular weight of 75,000.
• 4.4. Amino acid composition of W-PCPA was compared with that of bovine procarboxypeptidase as A S5 (PCPA-S5).
• 5.5. W-PCPA may be two subunits, and the aggregate form may resemble PCPA-S5.

     

Blood lipids of the small octopus,Octopus tehuelchus (mollusca,cephalopoda) at different stages of sexual maturation

• 1.1. The lipid and fatty acid composition from the plasma and hemocytes in Octopus tehuelchus at different stages of sexual development, was determined.
• 2.2. The highest content of lipids was found in females engaged in egg development, and the lowest in post-spawning and brooding females. Highest levels occurred during the autumn season in both sexes.
• 3.3. Changes were mainly due to triacylglycerols and diacylglyceryl ethers.
• 4.4. The plasma fatty acid composition did not demonstrate significant changes at different stages of maturation. The arachidonic acid (20:4 ω 6) was present at surprisingly high levels.

     

Fatty acid composition of depot fats,and rumen wall of the camel (Camelus dromedarius

• 1.1. Fatty acid composition of depot fats (hump, subcutaneous, mesentry, abdomen, perinephric and peticardiac) and rumen wall of Camelus dromedarius were studied by gas-liquid chromatography.
• 2.2. All depot fats showed similar characteristics; major fatty acids found were palmitic, stearic, oleic and myristic. Small quantities of odd-numbered, palmitoleic, linoleic and linolenic acids were also present.
• 3.3. Fatty acid of rumen wall showed some differences from the general pattern.
• 4.4. Fatty acid composition of the camel is discussed in relation to that of other ruminants and monogastrics.

     

A thioredoxin from the extreme thermophilic Archaeon Sulfolobus solfataricus

• 1.1. A purification procedure for a thioredoxin from the extremophilic archaeon Sulfolobus solfataricus is described.
• 2.2. The thioredoxin is active in the dithiothreitol-dependent reduction of insulin disulfide bonds.
• 3.3. The thioredoxin is a monomer of 24,800 Da; it is an acidic protein with a pi of 4.5.
• 4.4. The protein is stable to heating for 3 hr at 90°C.
• 5.5. The amino acid composition of S. solfataricus thioredoxin is reported.

     

Characterization of subfractions of β2-glycoprotein I: Evidence for sialic acid microheterogeneity

• 1.1. β₂-Glycoprotein I is a sialic acid microheterogeneous protein and contains on the average 11 mol sialic acid/mol.
• 2.2. Linear correlation was found between sialic acid content and pI of isolated subfractions.
• 3.3. Asialo-β₂2-glycoprotein I consists of 2 isoforms. Each of which can originate from the same subfraction.
• 4.4. The isolated subfractions exhibited almost the same amino acid composition.

     

Purification and characterization of the d-lactate dehydrogenase from Leuconostoc lactis

• 1.1. The d-lactate dehydrogenase from Leuconostoc lactis has been purified in high yield.
• 2.2.The enzyme is a dimer of subunits of M_r = 39,000 and each subunit contains a single thiol group. The N-terminal residue is methionine.
• 3.3. The amino acid composition has been determined and is typical of that of a soluble globular protein.

     

Locust vitellogenin receptor: an acidic glycoprotein with N- and O-linked oligosaccharides

• 1.1. The locust vitellogenin (VTG) receptor which is embedded in oocyte plasma membranes is a glycoprotein.
• 2.2. With various lectins oligosaccharide units have been identified, among them neuraminic acid linked to Gal or GalNAc, mannose chains, Gal linked to GalNAc or GlcNAc and fucose linked to GlcNAc.
• 3.3. With specific enzymes it could be shown that mannose and most other oligosaccharides are O-linked while others like fucose are N-linked.
• 4.4. Enzymatic removal of all O-linked carbohydrates resulted in a drop of the molecular mass of the receptor protein from 200,000 to 110,000.
• 5.5. A total of N- and O-linked oligosaccharides of 54% was calculated.
• 6.6. The isoelectric point of the receptor was found to be at pH 3.4 increasing slightly after removal of neuraminic acid.
• 7.7. Removal of neuraminic acids destroyed the binding ability for VTG.

     

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.

     

Presence of an essential polyunsaturated fatty acid in intradigestive bacterial symbionts of a deposit-feeder echinoid (Echinodermata)

• 1.1. Fatty acids were isolated from bacteria of the family Beggiatoaceae and closely related to the genus Thiothrix. These bacteria are symbionts that live in the gut of Echinocardium cordatum.
• 2.2. Ten pronounced chromatographic peaks were observed that correspond to 14:0, 15:0, 15:0, 16:0, 16:1, 17:0, 18:0, 18:1, 18:3 and 19:0 fatty acids.
• 3.3. The fatty acid 18:3 had a retention time and mass spectrum identical to those of linolenic acid.
• 4.4. The presence of an essential fatty acid has never before been reported in a non-photosynthetic organism. This essential fatty acid in the symbiotic bacteria could be of nutritional importance for their echinoid host.
• 5.5. The presence of this essential fatty acid supports a phylogenetic affinity between Beggiatoaceae and Cyanobacteria that are the only bacteria known to synthetize linolenic polyunsaturated fatty acid (PUFA).

     

Proteolytic system in Babesia hylomysci

• 1.1. Babesia hylomysci has an aminopeptidase and an acid endoprotease
• 2.2. The amino-peptidase has properties very similar to the aminopeptidase in Plasmodium yoelii nigeriensis and P. chabaudi.
• 3.3. The acid endoprotease is specific towards haemoglobin and practically has no action on bovine serum albumin.
• 4.4. In mouse normal red blood cells we find an acid protease having physico-chemical properties similar to the enzyme present in B. hylomysci extracts.
• 5.5. The similarity of electrophoretic velocity between acid protease in B. hylomysci and non-infected red blood cells leads us to think that the acid protease of parasitic extracts comes from the host-cell.
• 6.6. The proteolytic system of Babesia and Plasmodium are similar.

     

Kinetic studies of the transphosphorylation reactions catalyzed by alkaline phosphatase from E. coli: Hydrolysis of p-nitrophenyl phosphate and o-carboxyphenyl phosphate in presence of tris

• 1.1. Transphosphorylation of p-nitrophenyl phosphate and o-carboxyphenyl phosphate to Tris, has been studied at alkaline and acid pH.
• 2.2. The rate of release for all reactions products was Tris-dependent for both substrates, with a slight maximum for phenol at alkaline pH. These dependences have been analyzed from a mechanistic standpoint.
• 3.3. Individual constants of rate of a simple transphosphorylation mechanism have been determined.
• 4.4. At high Tris concentrations (> 1.0 M) a slight competitive inhibition has been observed.
• 5.5. Inhibition in NH₄⁺-NH₃Cl buffer has been found at alkaline pH but not at acid pH. It would therefore seem that the non-protonated NH₂ group of Tris is responsible for inhibition.
• 6.6. The results suggest the formation of complexes between Tris and the enzyme. Other possible alternatives are also analyzed.

     

Oxygen binding by the hemocyanin of Busycon canaliculatum

• 1.1. This study examined the effect of the monoamines dopamine and octopamine, as well as tyrosine on the oxygen affinity and cooperativity of oxygen binding by the hemocyanin of the marine gastropod Busycon canaliculatum. The effect of temperature on hemocyanin oxygen affinity was also examined.
• 2.2. Freezing Busycon hemocyanin did not affect the binding of oxygen.
• 3.3. Dopamine, octopamine and tyrosine had no significant effect on the oxygen affinity or cooperativity of oxygen binding by the hemocyanin of B. canaliculatum.
• 4.4. It was concluded that Busycon hemocyanin either has no binding sites for the two monoamines or for tyrosine, or that binding of the molecules has no functional significance.
• 5.5. Both temperature sensitivity and affinity of hemocyanin-oxygen binding were similar to values previously reported for hemocyanin of Busycon from other localities.

     

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.

     

Plasma membrane: Can its structure and function be modulated by dietary fat?

• 1.1. Compositional analysis of plasma membranes from rats fed nutritionally adequate diets different in fatty acid composition establishes that fundamentally different dietary fat intake results in alteration in structural lipid composition of plasma membranes in brain, liver and the intestinal mucosa.
• 2.2. Dietary differences in fatty acid intake altered the fatty acyl tail composition of plasma membrane phospholipids in brain, liver and intestinal mucosa.
• 3.3. Diet altered the phospholipid profile observed in brain synaptosomal and liver plasma membrane.
• 4.4. Feeding high vs low polyunsaturated to saturated fat diets for 7 days altered the fatty acid composition of phosphatidylcholine, phosphatidylethanolamine, sphingomyelin and mono-glucosylceramide isolated from plasma membrane of the intestinal mucosa