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At least 523 records · Page 29Linked to original sources
PubMed1983

Hemagglutinin activity in Nereis coelomic fluid.

1. Nereis coelomic fluid agglutinates rat, mouse, chicken, guinea pig and rhesus monkey erythrocytes (RBC). 2. Lipid fractions of the particulate matter from coelomic fluid are hemagglutinins exhibiting different activity inhibition profiles with complex polysaccharides. 3. The high mol. wt hemagglutinin from coelomic fluid supernatant is not a protein and is inhibited by bovine submaxillary mucin (BSM), thyroglobulin, transferrin and their asialo derivatives. 4. Coelomic fluid supernatant has a population of low mol. wt protein hemagglutinins inhibited by BSM, fetuin, antiserum to coelomic fluid and some mannan preparations. 5. Hemagglutination by lipids characterized by RBC specificity and specificity for inhibition by carbohydrate is noteworthy and may be significant in studies of cellular interactions and immunity in invertebrates.

Agglutinins↗
PubMed1988

Oxygen consumption and feeding rates of the sabellid polychaete, Myxicola infundibulum (Renier).

1. Rates of respiration and feeding were measured for the sabellid polychaete, Myxicola infundibulum. 2. Basal rates of respiration were 1.5 times lower than routine rates. 3. Clearance and irrigation rates were independent of cell type when the worms were fed on monocultures of algae; however, preferential selection was seen when the algal species were offered simultaneously. 4. Calculations indicate that this species can meet its energetic needs at rather low cell densities. 5. It is suggested that these low energy requirements, coupled with the capacity for high pumping/clearing rates may be of adaptive significance in reducing competition for food resources.

Animals↗
PubMed1984

An ion-site interaction model for sodium currents in the giant axon.

The time and voltage dependence of sodium currents in the Myxicola giant axon were examined as functions of the external sodium concentration. The results were incompatible with a model of free diffusion through a gated channel, but lent themselves to analysis in terms of a model involving a positive cooperative homotropic reaction in which Na+ interacts with two allosteric sites - a regulatory site and a transfer site - at the 'sodium channel'. The time-dependent solution of the rate equations describing the kinetics of the transfer reaction was derived as an expression describing the sodium current as a function of time, membrane potential and external sodium concentration. This function was used to test the validity of the model by its ability to predict the nerve excitability properties. The predicted i-v and i-t curves fitted the experimental results (p less than 0.005 and p less than 0.05, respectively). The computed parameters of these functions are consistent with other experimental results. The possibility of a noncooperative reaction was rejected.

Animals↗
PubMed1996

Wheat germ agglutinin-reactive chains of giant hemoglobin from the polychaete Perinereis aibuhitensis.

Wheat germ agglutinin-reactive chains of multisubunit extracellular hemoglobin from the polychaete Perinereis aibuhitensis were identified to clarify the carbohydrate gluing which is the carbohydrate-dependent supramolecular architecture of the hemoglobin (Ebina S. et al. (1995) Proc. Natl. Acad. Sci. USA 92, 7367-7371). Electron microscope micrographs of Perinereis hemoglobin showed a characteristic shape of two-tiered hexagonal rings whose diameter and height were determined to be 29.4 +/- 1.7 nm and 20.0 +/- 1.8 nm, respectively. Four types of globins and two types of linkers were isolated from the giant hemoglobin by reverse-phase chromatography and SDS-PAGE. These constituents showed similar NH2-terminal sequences as those previously reported for corresponding chains of Tylorrhynchus hemoglobin (Suzuki T. and Gotoh T. (1986) J. Biol. Chem. 261, 9257-9267; Suzuki T. et al. (1990) J. Biol. Chem. 265, 12168-12177). Thus, each globin of Perinereis hemoglobin was identified in terms of amino acid sequence homology and designated using names common to Tylorrhynchus hemoglobin, namely, a, A, b, and B. The linkers were stained by horseradish peroxidase (HRP)-lectins and PAS staining kits, indicating the presence of carbohydrate oligomers. Lectin staining was also significantly positive to globins a and A, which belong to strain A, but negative to globins b and B, which belong to strain B. Results showed that linkers and globins of strain A had a site in a carbohydrate oligomer to which wheat germ agglutinin (WGA) could bind. On the other hand, an alignment between known amino acid sequences of annelid globins and linkers and the sequences of lectins revealed that only the domain of the cysteine-rich motif in linkers has a homology with WGA-type lectins. The results of this study clarify the structuring mechanism of a supramolecule by lectin-like binding, called carbohydrate gluing.

Amino Acid Sequence↗
PubMed1979

Apparent inhibition of pyruvate kinase by phosphocreatine and phosphoarginine.

1. Addition of a non-dialysable, heat-labile and acid-precipitable factor which was not absorbed on DEAE-cellulose column, could restore the sensitivity of the chromatographed muscle pyruvate kinase from Marphysa sanguinea towards phosphocreatine inhibition. 2. This factor, being non-specific as it acts on pyruvate kinase isozymes from different sources, demonstrated high creatine kinase activity. 3. High concentrations of ADP, creatine or replacement of ADP with IDP/UDP or high pH abolished the inhibition indicating that the inhibition was mediated through creatine kinase by depleting ADP. 4. Apparent inhibition of phosphocreatine was related to the relative activities of 3 intracellular enzymes--pyruvate kinase, creatine kinase and adenosine triphosphatase.

Animals↗