Effects of amino acid mutations in the pore-forming domain of the hemolytic lectin CEL-III

The hemolytic lectin CEL-III forms transmembrane pores in the membranes of target cells. A study on the effect of site-directed mutation at Lys405 in domain 3 of CEL-III indicated that replacements of this residue by relatively smaller residues lead to a marked increase in hemolytic activity, suggesting that moderately destabilizing domain 3 facilitates formation of transmembrane pores through conformational changes

Foraging Behavior of Cattle in a Diverse, Mountainous Grazing Land: Bite Size Estimation of Plants by Hand-plucking Method

Poster Session

Physiological and Ultrastructural Studies on the Origin of Activator Calcium in Body Wall Muscles of Spoon Worms

To examine the origin of activator Ca and its translocation during contraction in body wall muscles (BWM) of spoon worms, Urechis unicinctus , physiological and ultrastructural studies, including cytochemistry, were performed. The potassium (K-) contracture tension was significantly reduced by the removal of external Ca, and by the application of Mn, La and verapamil. On the other hand, caffeine induced a prolonged contraction. The removal of Ca and Mg from the external solution, and the rapid cooling caused an irregular or oscillatory contraction. These results suggested that, in BWM fibers, the activator Ca is supplied partially from both external solution and intracellular Ca-accumulating structures. Ultrastructural observations revealed that the muscle fibers contain a relatively large amount of sarcoplasmic reticulum (SR). The fractional volume of the SR relative to the fiber volume was 2~5% in all fibers of three muscle layers. To demonstrate the Ca localization, the muscle fibers were fixed by pyroantimonate (PA) methods at resting and contracting states. In the resting fibers, the PA precipitates were exclusively localized in the SR and the inner surface of plasma membrane. On the other hand, in the contracting fibers, they were diffusely distributed in the central regions of myoplasm, and had disappeared from the SR and plasma membrane. X-ray microanalysis revealed that the PA precipitates contain Ca. With the results of physiological experiments, these results indicate that the activator Ca originates not only from the external solution, but also from the intracellular Ca-accumulating structures, the SR and the inner surface of plasma membrane.Full-Length Pape

Application of a Wearable Camera to Analyze Ingestive Behavior of Grazing Cattle

Poster Session

Electron Microscope Studies on the Structural Complex of Transverse Tubules and Sarcoplasmic Reticulum in Scorpionfish Swimbladder Muscles

To clarify the distribution of transverse tubule-sarcoplasmic reticulum (T-SR) com-plexes in the swimbladder muscle (SBM) of the scorpionfish (Sebastiscus marmoratus ), elec-tron microscope observations were performed. In the anterior part of the SBM, Z-type triads were exclusively observed, in contrast to the regular distribution of AI- and Z-type triads with pentads and heptads in the posterior part of the SBM reported in our previous paper. Various body muscles of scorpionfish contained only Z-type triads. Furthermore, SBM and body wall muscles (BWM) in other sound-producing fishes each contained only one type of triadic con-tacts. In the posterior fibers of scorpionfish SBM, feet on the junctional SR membrane formed a square lattice with three or more vertical lines and numerous horizontal rows. Isolation and identification of ryanodine receptor (RyR) revealed that αRyR and βRyR coexist in the SBM and BWM of scorpionfish. Anti-αRyR and βRyR antibodies were produced in rabbits, and im-munoelectron microscopy with these antibodies demonstrated that both αRyR and βRyR form parallel lines respectively on the same junctional membrane as AI- and Z-type triads. The re-sults are discussed in connection with the anatomical features and function of the swimbladder.Full-Length Pape