Some properties of salivary amylases of Adelphocoris suturalis (Miridae), Dolycoris baccarum (Pentatomidae), and several other heteropteran species

Some properties of salivary amylases of the adults of Adelphocoris suturalis Jakovlev and Dolycoris baccarum L. were studied in vitro and compared with those of several other heteropteran species. The reducing sugar produced by the action of the salivary amylase of D. baccarum increased in proportion to substrate concentration while the concentration was relatively low (below 0.67% in its final concentration). Its increase stopped at the concentrations from 0.67 to 2.0%, and then it increased again constantly but slowly. The optimum temperature for the action of the enzyme was found to be about 50° (in A. suturalis) and about 40° (in D. baccarum), and the optimal pH was 3.5–4.0 in A. suturalis and 6.0 in D. baccarum. The salivary amylase activity of D. baccarum was scarcely affected by NaCl, KNO₃, and other compounds, while the salivary amylase of A. suturalis was strongly activated by NaCl and moderately by KNO₃. It seems highly probable that taxonomically related heteropterous insects might well be grouped with respect to the degree of activation of the salivary amylase by Cl- or NO₃-.

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Zusammenfassung Einige Eigenschaften der Speichelamylase von Adelphocoris suturalis und Dolycoris baccarum wurden im Reagenzglas studiert und mit denen anderer Heteropterenarten verglichen. Die durch die Wirkung der Speichelamylase von D. baccarum produzierten Stärkehydrolysate vermehrten sich im Verhältnis zur Substratkonzentration bei einer verhältnismäßig niedrigen Konzentration (weniger als 0,67% in der Schlußkonzentration). Diese Vermehrung wurde bei einer Konzentration von etwa 0,67 bis 2,0 unterbrochen, um sich dann wieder stetig, aber langsamer fortzusetzen. Die optimale Temperatur für die Wirkung des Fermentes lag für A. suturalis bei etwa 50° und für D. baccarum bei etwa 40°. Die optimale Wasserstoff-Ionenkonzentration betrug für A. suturalis pH 3,5–4,0 und für D. baccarum pH 6,0. Die Aktivität der Speichelamylase von D. baccarum wurde durch NaCl, KNO₃ und andere Verbindungen kaum beeinflußt, während die Speichelamylase von A. suturalis durch NaCl stark und durch KNO₃ schwach aktiviert wurde. Es wird vermutet, daß, hinsichtlich des Aktivierungsgrades der Speichelamylase durch Cl- und NO₃-, systematisch nahe verwandte Heteropterenarten der gleichen Gruppe angehören.

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Contribution No. 28 from the Laboratory of Entomology, Obihiro Zootechnical University.     

Two kinds of thick filament in smooth muscle cells in the adductor of a clam, Chlamys nobilis

The ultrastructure of the opaque portion of the adductor muscle in the pecten Chlamys nobilis was investigated. The opaque portion was composed of smooth muscle cells that contained thin and thick filaments. The thick filaments were classified into two kinds, thinner and thicker, according to the statistical analysis of diameters. They were also classified as being shorter and longer, when isolated native filaments were examined. The thick filaments may consequently be classified into two kinds: thinner and shorter filaments, and thicker and longer ones. The thinner and shorter filaments were about 26.5 nm in diameter and 7.5 mum in length, and the thicker and longer ones were about 42.0 nm in diameter and 13.0 mum in length, respectively. A regular periodicity was apparent on the surface of the core after removal of myosin molecules from its surface. The periodicity seemed similar for the two kinds of thick filament.     

Purification and properties of Renilla reniformis luciferase.

Luciferase from the anthozoan coelenterate Renilla reniformis (Renilla luciferin:oxygen 2-oxidoreductase (decarboxylating), EC 1.13.12.5.) catalyzes the bioluminescent oxidation of Renilla luciferin producing light (lambdaB 480 nm, QB 5.5%), oxyluciferin, and CO2 (Hori, K., Wampler, J.E., Matthews, J.C., and Cormier, M.J. (1973), Biochemistry 12, 4463). Using a combination of ion-exchange, molecular-sieve, sulfhydryl-exchange, and affinity chromatography, luciferase has been purified, approximately 12 000-fold with 24% recovery, to homogeneity as judged by analysis with disc and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, gel filtration, and ultracentrifugation. Renilla luciferase is active as a nearly spherical single polypeptide chain monomer of 3.5 X 10(4) daltons having a specific activity of 1.8 X 10(15) hp s-1 mg-1 and a turnover number of 111 mumol min-1 mumol-1 of enzyme. This enzyme has a high content of aromatic and hydrophobic amino acids such that it has an epsilon280nm 0.1% of 2.1 and an average hydrophobicity of 1200 cal residue-1. The high average hydrophobicity of luciferase, which places it among the more hydrophobic proteins reported, is believed to account, at least in part, for its tendency to self-associate forming inactive dimers and higher molecular weight species.     

Involvement of Sema4A in the progression of experimental autoimmune myocarditis

Dilated cardiomyopathy often results from autoimmunity triggered by microbial infections during myocarditis. However, it remains unclear how immunological disorders are implicated in pathogenesis of autoimmune myocarditis. Here, we demonstrated that Sema4A, a class IV semaphorin, plays key roles in experimental autoimmune myocarditis (EAM). Dendritic cells pulsed with myosin heavy chain-α peptides induced severe myocarditis in wild-type mice, but not in Sema4A-deficient mice. In adoptive transfer experiments, CD4⁺ T-cells from wild-type mice induced severe myocarditis, while CD4⁺ T-cells from Sema4A-deficient mice exhibited considerably attenuated myocarditis. Our results indicated that Sema4A is critically involved in EAM by regulating differentiation of T-cells.