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PubMed2005

A quantitative survey of mycosporine-like amino acids (MAAS) in intertidal egg masses from temperate rocky shores.

Mycosporine-like amino acids (MAAs) have been reported as functional chemical sunscreens in a variety of marine organisms, but their role in development of marine embryos and larvae remains largely unexplored. In this study, we quantified MAAs from intertidal egg masses of 46 species of mollusks, two species of polychaetes, and one species of fish from southeastern Australia. We aimed to elucidate potential patterns of occurrence and variation based on egg mass maturity, adult diet, spawning habitat, phylogeny, and viability. Our analyses revealed that maturity and spawning habitat did not affect MAA composition within egg masses. In contrast, adult diet, phylogeny, and viability affected MAA composition. Herbivores had higher levels of certain MAAs than carnivores; similarly, viable egg masses had higher levels of some MAAs than inviable ones. MAA composition varied according to the taxonomic group, with nudibranchs and anaspids showing different MAA composition compared to that of neogastropods, sacoglossans, and polychaetes. Basommatophoran egg masses had more porphyra-334 than the other taxa, and anaspids had more mycosporine-2-glycine than the other groups. MAAs occurred in relatively high concentrations in intertidal molluskan egg masses when compared to adult mollusks and other common intertidal organisms. Despite the complexity of factors affecting MAA composition, the prevalence of MAAs in some species is consistent with protection afforded to offspring against negative effects of UV radiation.

Animal Feed↗
PubMed2005

Partial sequence of connectin-like 1200K-protein in obliquely striated muscle of a polychaete (Annelida): evidence for structural diversity from vertebrate and invertebrate connectins.

Vertebrate striated muscle contains the giant elastic protein connectin that maintains the position of the A-band at the center of the sarcomere during repeated muscular contraction and relaxation. Connectin-like molecules may perform conserved functions in vertebrate and invertebrate striated and oblique muscles, although less is known about the structure of invertebrate connectins at present. The protein that maintains such a structure is present not only in vertebrate striated muscle, but also in invertebrate striated and oblique muscle. In the present study, we analyzed the partial primary structure of a 1200K-protein, which is a connectin-like protein that is expressed in Neanthes sp. body wall muscle that is in turn composed of oblique muscle. Antibody screening of a cDNA library of Neanthes sp. body wall muscle identified two different clones. Both clones coded for a sequence predominantly comprised of the four amino acids proline (P), glutamate (E), valine (V) and lysine (K). One clone included a PEVK-like repeat sequence flanked by an Ig domain, while the other clone comprised a distinct 14 amino acid repeat rich in PEVK residues, flanked by a non-repetitive unique sequence. The PEVK region is found in vertebrate connectin and is thought to generate elasticity and be responsible for passive tension of the muscle. The antibodies produced against a portion of each clone both reacted with bands corresponding to 1200 kDa present in Neanthes sp. body wall muscle. Therefore, our results demonstrate that this 1200K-protein is a connectin-like elastic protein and includes specific PEVK-like fragment. We suggest that this 1200K-protein plays a major role in maintaining the structure of oblique muscle in invertebrates.

Amino Acid Sequence↗
PubMed1984

High-performance liquid chromatographic separation of glycopeptides from Nereis cuticle collagen.

To facilitate the structural studies of invertebrate collagens, a sensitive and effective method was developed, using reverse-phase high-performance liquid chromatography for preparative isolation of the collagen subunits and their clostridial collagenase-derived peptides; the methods have been applied to Nereis cuticle collagen. The two subunits of denatured Nereis cuticle collagen, termed A and B, were initially separated by high-performance liquid chromatography. These polypeptides, with Mr of about 0.5 million, were each exhaustively digested with clostridial collagenase. The digest of the A subunit, which contains all of the uronic acid, was enriched for the uronic acid-containing glycopeptides by means of gel filtration. These glycopeptides were resolved into 23 major peaks, using reverse-phase HPLC, over a 5-h elution time, with an acetonitrile gradient (0-20%) containing 0.1% TFA. The amino acid composition data suggests that the peptides are of variable length, from 5 to 17 residues, while beta-elimination studies show that the uronic acid-containing moieties are all O-glycosidically linked to threonine residues, in the peptides examined. The amino acid sequence of one of the major glycopeptides was determined and found to be Gly-Hyp-Ala-Gly-Gly-Ile-Gly-Glu-Thr-Gly-Ala-Val-Gly-Leu-Hyp. The amino acid compositions of glycosylated and nonglycosylated peptides which had eluted, numbering about 100, showed a correspondence between hydrophobicity or hydrophilicity and emergence time from the column. We also found that the peptides most enriched in 4-hydroxyproline emerged earliest. These studies provide a foundation for elucidating the detailed structures of the large, unusual subunits of a well-characterized cuticle collagen.

Amino Acid Sequence↗
PubMed1985

Nonfluorescent negative stain for alanopine dehydrogenase activity on starch gels.

A two-step procedure for negative staining NADH-dependent alanopine dehydrogenase (ALPDH) activity on starch gels is described, using nitroblue tetrasolium and phenasine methosulfate. This method gives a blue background with unreacted NADH, and white areas where ALPDH is located. Using this technique the first reliable evidence of the existence of true ALPDH isoenzymes is obtained.

Animals↗
PubMed1987

A method for the production of highly specific polyclonal antibodies.

Two polyclonal antibodies directed against paramyosin and tropomyosin from Owenia fusiformis (a marine polychete annelid) were obtained using a new method of immunization. After purification by two-dimensional gel electrophoresis, proteins were transferred onto a nitrocellulose sheet using the Western blot technique. The proteins bound to their cellulose support were injected into rabbits without Freund's adjuvant and without solubilization of nitrocellulose with dimethyl sulfoxide. Highly specific polyclonal antibodies were generated.

Animals↗
PubMed1990

Metalloprotein separation and analysis by directly coupled size exclusion high-performance liquid chromatography inductively coupled plasma mass spectroscopy.

The feasibility of using directly coupled size exclusion high-performance liquid chromatography inductively coupled plasma mass spectroscopy (HPLC/ICP-MS) for the separation and subsequent elemental analysis of metalloproteins in biological samples has been studied. Data, on up to eight elements, was acquired simultaneously and the reconstructed elemental profiles from the chromatographed samples were quantified by flow injection analysis. Absolute and relative detection limits, reproducibility, operational dynamic range, and linearity of response were initially evaluated by analyzing standards of metallothionein protein of known elemental composition for Cd, Zn, and Cu. There was evidence of displacement of Zn from the protein during chromatography and the substitution of Cu sequestered from the mobile phase. Cd associated with the protein was fully recovered during chromatography. Memory effects, due to protein adsorption to the glassware in the torch box, were minimal and there was no degradation of the resolution of the chromatographed peak during extended transport through the HPLC/ICP-MS interface. The versatility of the technique has been demonstrated by the quantitative multi-element analysis of cytosolic metal-binding proteins separated from the polychaete worm Neanthes arenaceodentata. Fidelity of analysis has been demonstrated by two independent procedures: first, by comparing the elemental profiles obtained by directly aspirating the HPLC eluant into the ICP-MS to those obtained by collecting fractions and quantifying the metal content of the proteins in the conventional analytical mode; second, by comparing the stable isotopic profiles for 114Cd obtained by simultaneous ICP-MS analysis with radiometric profiles of 109Cd obtained by counting radioactivity associated with collected fractions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

ATP sulfurylase from trophosome tissue of Riftia pachyptila (hydrothermal vent tube worm).

ATP sulfurylase (ATP: sulfate adenylyltransferase, EC 2.7.7.4) was extensively purified from trophosome tissue of Riftia pachyptila, a tube worm that thrives in deep ocean hydrothermal vent communities. The enzyme is probably derived from the sulfide-oxidizing bacteria that densely colonize the tissue. Glycerol (20% v/v) protected the enzyme against inactivation during purification and storage. The native enzyme appears to be a dimer (MW 90 kDa +/- 10%) composed of identical size subunits (MW 48 kDa +/- 5%). At pH 8.0, 30 degrees C, the specific activities (units x mg protein-1) of the most highly purified sample are as follows: ATP synthesis, 370; APS synthesis, 23; molybdolysis, 65; APSe synthesis or selenolysis, 1.9. The Km values for APS and PPi at 5 mM Mg2+ are 6.3 and 14 microM, respectively. In the APS synthesis direction, the Km values for MgATP and SO4(2-) are 1.7 and 27 mM, respectively. The Km values for MgATP and MoO4(2-) in the molybdolysis reaction are 80 and 150 microM, respectively. The Kia for MgATP is 0.65 mM. APS is a potent inhibitor of molybdolysis, competitive with both MgATP and MoO4(2-) (Kiq = 2.2 microM). However, PPi (+ Mg2+) is virtually inactive as a molybdolysis inhibitor. Oxyanion dead end inhibitors competitive with SO4(2-) include (in order of decreasing potency) ClO4- greater than FSO3- (Ki = 22 microM) greater than ClO3- greater than NO3- greater than S2O3(2-) (Ki's = 5 and 43 mM). FSO3- is uncompetitive with MgATP, but S2O3(2-) is noncompetitive. Each subunit contains two free SH groups, at least one of which is functionally essential. ATP, MgATP, SO4(2-), MoO4(2-), and APS each protect against inactivation by excess 5,5'-dithiobis-(2-nitrobenzoate). FSO3- is ineffective as a protector unless MgATP is present. PPi (+Mg2+) does not protect against inactivation. Riftia trophosome contains little or no "ADP sulfurylase." The high trophosome level of ATP sulfurylase (67-176 ATP synthesis units x g fresh wt tissue-1 from four different specimens, corresponding to 4-10 microM enzyme sites), the high kcat of the enzyme for ATP synthesis (296 s-1), and the high Km's for MgATP and SO4(2-) are consistent with a role in ATP formation during sulfide oxidation, i.e., the physiological reaction is APS + MgPPi in equilibrium SO4(2-) + MgATP.

Adenosine Phosphosulfate↗
PubMed1981

Reversal potentials corresponding to mechanical stimulation and leakage current in Myxicola giant axons.

The response of a Myxicola infundibulum giant axon to a transverse mechanical stimulus is an increase in membrane conductance. The similarity of the reversal potential for this conductance increase and the reversal potential for leakage current, together with other similarities, suggest similar pathways for these two processes. Depolarization of the reversal potential with increased mechanical stimulus is best explained in terms of a gradual change in the mechanically-stimulated ionic pathways.

Animals↗
PubMed1985

Significant potassium ion accumulation at the external surface of Myxicola giant axons.

Potassium accumulation associated with outward membrane potassium current was investigated experimentally in Myxicola giant axon. During prolonged voltage-clamp pulses to positive transmembrane potentials, the K+ equilibrium potential may approach zero mV, suggesting massive K+ accumulation outside the axonal membrane to concentrations many-fold higher than those in the bathing medium. The potassium accumulation can be satisfactorily described by a three-compartment model, consisting of the nerve fiber, a restricted physiological periaxonal space and the bulk solution. The average thickness, theta, of the periaxonal space is calculated as 177 +/- 59 A, i.e., comparable to that in the squid, while the permeability coefficient of the external barrier, PKs, was calculated to be (1.4 +/- 0.4) X 10(-4) cm/s. These conclusions are well supported by morphological study.

Animals↗
PubMed1985

ATP-dependent calcium accumulation by non-mitochondrial organelles of axoplasm isolated from Myxicola giant axons.

Axoplasm from freshly isolated Myxicola giant axons was mixed with small volumes of 'artificial axoplasm' containing 45Ca and either CaEGTA/EGTA or CaDTPA/DTPA buffers giving various nominal values of [Ca2+]. The axoplasm samples were centrifuged at 100 000 X g for 30 min to form a pellet and the percentage of 45Ca bound to the pellet was determined. The fraction of bound calcium rose with increasing values of [Ca2+] along an S-shaped curve. Carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP) was used to reveal the presence of mitochondrial Ca uptake. At physiological values of [Ca2+], around 100 nM, Ca uptake was insensitive to FCCP. As [Ca2+] was elevated, increasing sensitivity to FCCP was noted above [Ca2+] = 0.5 microM. At low values of [Ca2+], including the physiological range, Ca binding was significantly reduced by vanadate and quercetin, agents known to inhibit Ca uptake mediated by Ca2+-activated ATPase reactions. Inhibition of Ca binding by these agents was approximately 50% at physiological values of [Ca2+]. ATP depletion decreased the percentage of Ca binding by the pellet at physiological [Ca2+]. The results suggest that about 50% of the Ca buffering by particulate matter in axoplasm is via organelles requiring intact Ca2+-ATPase reaction at physiological values of [Ca2+].

Adenosine Triphosphate↗
PubMed1975

Molecular weight of Eudistylia vancouveri chlorocruorin and its subunits.

The chlorocruorin of the marine polychaete Eudistylia vancouveri has a molecular weight of 3.1-10(6) and a sedimentation coefficient (S020, w) of about 57 S at pH 8.0 in the presence of 0.01 M Mg2+. The quaternary structure of this pigment is unaffected by pH between 6.0 and 11.5 in the presence of 0.01 M Mg2+ whereas in 0l01 M EDTA, the pigment begins to dissociate above pH 9.0 into smaller submultiples. The chlorocruorin can be converted into subunits with molecular weights of about 14 000-15 000 and 30 000 as determined by sodium dodecyl sulfate-gel electrophoresis and 14 000-15 000 as measured by gel chromatography of the carboxy-methylated derivative in 8 M urea, 0.1 M 2-mercaptoethanol, or by sedimentation equilibrium in 6 M guanidine-HCl and 0.1 M 2-mercaptoethanol. The pigment contains 0.212 +/- 0.008% iron corresponding to 1 g atom iron per 26 300 g chlorocruorin. The amino acid composition of this pigment is reported. The subunit structure of Eudistylia chlorocruorin and the polymeric annelid hemoglobins are similar in many respects.

Amino Acids↗
PubMed1975

Comparative structural studies of the active site of ATP: guanidine phosphotransferases. The essential cysteine tryptic peptide of taurocyamine kinase from Arenicola marina.

The active cysteinyl residues of dimeric taurocyamine kinase from Arenicola marina were labelled with N-ethyl-[1-14C]maleimide. The resulting inactivated N-ethyl-[1-14C]succinimido enzyme was then subjected to tryptic hydrolysis. The peptide containing the labelled essential cysteinyl residue was isolated. The amino acid sequence of this peptide is Leu-Gly-Tyr-Leu-Gly-Thr-[14C]-Cys-Pro-Thr-Asn-Ile-Gly-Leu-Arg. This sequence is very similar to that of homologous ATP:guanidine phosphotransferases previously studied, arginine kinase from Homarus vulgaris muscle, creatine kinase from ox brain and ox muscle, and from rabbit muscle, and lombricine kinase from Lubricus terrestris.

Alkanesulfonates↗
PubMed1976

Isolation and characterization of a hemagglutinin from Amphitrite ornata, a polychaetous annelid.

Extracts of the marine polychaetous annelid, Amphitrite ornata, agglutinate rat, rabbit, chicken and human erythrocytes and in other work have been shown to inhibit the growth of Ehrlich ascites tumors in mice. Fractionation of extracts on Sephadex G-100 gave three active fractions with molecular weights of 30 000, 54 000 and 100 000. The 30 000 dalton fraction (B) was purified 72-fold by ammonium sulfate precipitation, gel filtration and preparative disc gel electrophoresis. The purified hemagglutinin, amphitritin, was homogenous on analytical disc gel electrophoresis at four different pH values and gave a sharp boundary in sedimentation velocity ultracentrifugation. The three fractions showed paralled specificity toward rat and chicken erythrocytes, the former giving the higher titer. The purified agglutinin was active toward human blood groups A, B and O and exhibited 4-fold higher activity toward group A. The hemagglutinin titer against rat red blood cells was lowered only by N-acetylgalactosamine, the terminal sugar residue of the group A determinant. None of the saccharides tested inhibited agglutination of chicken erythrocytes. Hemagglutinin activity was insensitive to dialysis or treatment with EDTA. The activity was not affected by digestion with trypsin or pronase, but was destroyed by phenol extraction. Analytical disc gel electrophoresis showed one protein band with high anodal mobility at pH 8.5, which was not affected by proteolytic enzymes but was removed by phenol. Activity was unaffected by heating at 70 degrees C for 30 min but was destroyed by similar treatemtn at 85 degrees C. Activity was at a maximum at pH 7-9 and decreased reversibly down to pH 4 at which point it was irreversibly inactivated. The higher molecular weight agglutinin (A1) could be dissociated to give amphitritin by treatment with 6M urea of precipitation in 55% (NH4)2SO4. This dissociation was not reversed by dialysis. Amphitritin is a glycoprotein with a molecular weight determined by gel filtration of 30 000 and by approach to equilibrium sedimentation of 32 000. Amino acid analysis showed a preponderance of aspartic and glutamic acids and relatively large amounts of glycine, proline, alanine, valine and cysteine. The carbohydrate moeity which represented 12.8% of the molecule, contained mannose, galactose, glucosamine and sialic acid. Amphitritin is the first hemagglutinin to be isolated from a polychaetous annelid.

ABO Blood-Group System↗
PubMed1981

Amphitrite ornata erythrocruorin. II. Molecular controls of function.

In the marine terebellid worm Amphitrite ornata the vascular fluid contains a high molecular weight erythrocruorin, while cells of the coelom contain a monomeric hemoglobin. The structural integrity of the erythrocruorin molecule is known to be dependent on the presence of a minimal concentration of divalent cations (1-3 mM) in the medium. The functional properties of Amphitrite erythrocruorin are also affected by cations. The oxygen affinity tends to increase with increasing cation concentration and the degree of cooperative interactions, expressed in the kinetics and equilibria of ligand binding, goes through a maximum. Maximal Hill coefficients of 3-4 are observed with 50 mM CaCl2, 50 mM MgCl2 or 1 M NaCl in measurements at the physiological pH of 7.75. Only 2 mM CaCl2 is required for maximal cooperativity at pH 8.5. This suggests partial deprotonation of the cation binding site at high pH. It is somewhat unusual that pH effects on cooperativity are reversible, since this is not a common feature of the giant erythrocruorin molecules. The oxygen binding experiments revealed a marked effect of divalent cations of Amphitrite erythrocruorin at high pH and cation concentration. Above pH 8.5, at 50 mM CaCl2 and 12 degrees C, the erythrocruorin will form a polymer upon deoxygenation. This polymerization is readily reversible by bringing the temperature for 12 to 20 degrees C or by oxygenation. Under physiological conditions of pH and cation concentration and at 12 degrees C, the erythrocruorin and the monomeric coelomic hemoglobin require a similar oxygen pressure for half saturation. However, the allosteric regulation of function is absent for the coelomic protein.

Animals↗