Modulation of transient type K channel cloned from rat heart.

We have cloned a transient type K channel from rat heart (RH10) and coexpressed a metabotropic glutamate receptor (mGluR5) to study the functional modulation of RH10 coupled to the phosphatidylinositol (PI) hydrolysis. Stimulation of mGluR5 suppressed peak amplitude of RH10 current and affected voltage dependence of activation and inactivation of the channel.     

Plant-growth regulators from common starfish (<Emphasis Type="Italic">Asterias amurensis</Emphasis> Lütken) waste

Starfish waste has been shown to be an effective compost material not only in the promotion of plant growth but also in terms of having insecticidal activity. In the present study, plant growth regulation by chemicals from starfish was examined. The aqueous fraction from a hot water extract of the starfish Asterias amurensis Lütken showed plant-growth activity, while the aqueous fraction from a methanol extract inhibited growth of Brassica campestris. The lipophilic fraction from the methanol extract also exhibited a plant growth-promoting effect. The active components from each extract were identified. Asterubine from the hot water extract promoted plant growth. A ceramide from the lipophilic fraction showed root growth promoting effect, and three glucocerebrosides had promotive effects on the entire plant. Asterosaponins were identified as the main growth inhibitors in the aqueous fraction of the methanol extract. These active compounds from starfish waste could be analyzed as potential plant growth regulators in agricultural applications in the future.     

Ibaraki Virus,an Agent of Epizootic Disease of Cattle Resembling Bluetongue

Replication of Ibaraki virus was not inhibited by 5-iodo-2′-deoxyuridine, indicating that the virus is an RNA virus. The virus was resistant to ether, chloroform and deoxycholate, sensitive to trypsin, very labile at acidic pH but stable at pH 6.4 or higher, and was resistant to repeated freezing and thawing. The virus was readily inactivated at 56 C or higher, was fairly stable at 37 C, and very stable at 4 C, while it rapidly lost infectivity when stored frozen at —20 C. The virus was readily sedimented by centrifugation at 40 000Xg for 60 min. It readily passed through membrane filters of 200 mμ pore size, passed through 100 μfilters but only with some titer loss and did not through 50 mμ filters. In these tests, the bluetongue virus used as a control behaved in the same manner as Ibaraki virus. These findings provide additional evidence for the similarity of Ibaraki virus to bluetongue virus which had been previously demonstrated on the basis of seasonal incidence, symptomatology and pathology of the diseases caused by these viruses and the behavior of the viruses in cell cultures, embryonated eggs and laboratory animals. The present study, however, provided no evidence for any serological relation between these two viruses. More Information is needed to reach a final decision on the classification of Ibaraki virus, particularly regarding the morphology of the virion, the doublestrandedness of the viral RNA and other basic features.     

Isolation and Identification of the Female Sex Pheromone of the Potato Tuberworm Moth,Phthorimaea operculella (Zeller)

The sex pheromone produced by adult females of the potato tuberworm moth was isolated from unmated female moths reared in the laboratory. The gas Chromatographic and mass spectrometric data suggested the pheromone to be a tridecatrienyl acetate. The isolated pheromone was subjected to partial hydrogenation with hydrazine and hydrogen peroxide and subsequent ozonolysis to produce a mixture of ω-acetoxy-alkanals. They were identified by mass Chromatographic technique as 4-acetoxy-butanal, 7-acetoxy-heptanal, and 10-acetoxy-decanal respectively. Consequently, the pheromone was identified as 4,7,10-tridecatrienyl acetate except the geometric configuration.     

Reactivities of the coordinated organonitriles in molybdenum(0) and tungsten(0) phosphine complexes: protonation of the nitrile carbon and cleavage of the CN triple bond

The molybdenum and tungsten dinitrogen-organonitrile complexes trans-[M(N₂)(NCR)(dppe)₂] (2, M=Mo; 4, M=W; R=Ph, C₆H₄Me-p, C₆H₄OMe-p, Me; dppe=Ph₂PCH₂CH₂PPh₂) underwent double protonation at the nitrile carbon atom with loss of N₂ and a change in oxidation state to +4 on treatment with hydrochloric acid to afford the cationic imido complexes trans-[MCl(NCH₂R)(dppe)₂]⁺. The solid-state structure of trans-[WCl(NCH₂CH₃)(dppe)₂][PF₆]·CH₂Cl₂ was determined by single-crystal X-ray analysis. Protonation of complexes 2 by fluoroboric acid or hydrobromic acid also formed the similar imido complexes trans-[MoX(NCH₂R)(dppe)₂]⁺ (X=F, Br). In contrast, the dinitrogen complex trans-[Mo(N₂)₂(dppe)₂] reacted with two equiv. of benzoylacetonitrile, a nitrile with acidic CH hydrogen atoms, to give the nitrido complex trans-[Mo(N)(NKCCHCOPh)(dppe)₂] (12), which was accompanied by evolution of dinitrogen and the formation of 1-phenyl-2-propen-1-one in high yields. For complex 12, the zwitterionic structure, where the anionic enolate ligand PhC(O⁺)=CHCN coordinates to the cationic Mo(IV) center through its nitrogen atom, was confirmed by spectroscopic measurements and single-crystal X-ray analysis. A unique intermolecular aromatic C---HO hydrogen bonding was observed in that crystal structure. Complex 12 is considered to be formed via the cleavage of the CN triple bond of benzoylacetonitrile on the metal. A reaction mechanism is proposed, which includes the double protonation of the nitrile carbon atom of the ligating benzoylacetonitrile on a low-valent molybdenum center.     

Primary structure of the tail sheath protein of bacteriophage T4 and its gene

Complete sequence determination of gene 18 encoding the tail sheath protein was carried out mainly by the Maxam-Gilbert method. Approximately 40 peptides contained in a tryptic digest and a lysyl endopeptidase digest of gp 18 were isolated by reversed-phase high-performance liquid chromatography. All the peptides were identified along the nucleotide sequence of gene 18 based on the amino acid compositions. These peptides cover 88% of the total primary structure. Furthermore, the amino acid sequences of 9 of the 40 peptides were determined by a gas-phase protein sequencer; one of them turned to be the N-terminal one. The C-terminal peptide in the tryptic digest was isolated from the unadsorbed fraction of affinity chromatography on immobilized anhydrotrypsin and the amino acid sequence was also determined. Thus, the complete primary structure of gp 18 was determined; it has 658 amino acid residues and a molecular weight of 71,160.This article was presented during the proceedings of the International Conference on Macromolecular Structure and Function, held at the National Defence Medical College, Tokorozawa, Japan, December 1985.     

Anti-parasite activity of nucleoside analogues: the metabolism of carbocyclic inosine in promastigotes of Leishmania tropica and Leishmania donovani and its activity against amastigotes of Leishmania donovani in vitro

Carbocyclic inosine is a potent inhibitor for the growth of the promastigote form of Leishmania tropica and Leishmania donovani. In culture, the EC50 values of carbocyclic inosine are 8.3 X 10(-8) and 1.3 X 10(-7) M for the promastigotes of L. tropica and L. donovani, respectively. On the other hand, it is less toxic towards mouse mammary tumor FM3A cells: the EC50 value is 2.7 X 10(-4)M. Carbocyclic inosine is metabolized by Leishmania promastigotes to give carbocyclic adenosine-5'-triphosphate(aristeromycin-5'-triphosphate) and carbocyclic guanosine-5'-triphosphate. This metabolic conversion provides a mechanism for the parasite-selective toxicity of carbocyclic inosine. Carbocyclic inosine was found to be active against L. donovani amastigotes in an in vivo-like cultivation in vitro.     

Evidence for acrosin-like enzyme in sperm extract and its involvement in fertilization of the ascidian,halocynthia roretzi

The presence of a protease has been demonstrated in sperm of the solitary ascidian, Halocynthia roretzi, by using t-butyloxycarbonyl-L-Val-L-Pro-L-Arg-4-methylcoumaryl-7-amide (Boc-Val-Pro-Arg-MCA) and other arginyl or lysyl MCA derivatives as substrates. Several properties of the enzyme were investigated in a crude extract. The activity had a pH optimum near 8.0 and was enhanced by the addition of CaCl₂. The Km value of 87μM was determined for Boc-Val-Pro-Arg-MCA under the optimal conditions. An apparent molecular weight was estimated to be 35,000 by gel filtration. The enzyme was inhibited with diisopropyl fluorophosphate, leupeptin, antipain, p-aminobenzamidine, Val-Pro-Arg-CH₂Cl, and soybean trypsin inhibitor, but scarcely inhibited with chymostatin, elastatinal, p-chloromercuribenzoic acid, tosyl-Lys-CH₂Cl, and tosyl-Phe-CH₂Cl. Boc-Val-Pro-Arg-MCA, the most susceptible of the substrates examined, showed the most effective inhibition against fertilization of ascidian eggs. Thus, this enzyme in ascidian sperm extract has features closely similar to mammalian acrosin [EC 3.4.21.10], and we conclude that the enzyme is involved in fertilization as one of the lysins.