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.     

Analysis of common antigen of flagella in Bacillus cereus and Bacillus thuringiensis

Abstract Flagellar antigen of Bacillus cereus H.1 was purified and tested for serodiagnostic antigen by ELISA. The antibody against the flagellar antigen of B. cereus H.1 reacted not only with the homologous specific antigen but also reacted with the flagellar antigens of 23 strains of B. cereus . This common flagellar antigen of B. cereus was found to be due to 61-kDa protein by SDS-PAGE and immunoblot assay. Monoclonal antibody H15A5 against common antigenic epitope of B. cereus also reacted with flagellar antigens of 21 strains of Bacillus thuringiensis by ELISA. This monoclonal antibody reacted with the 61-kDa protein of the flagella of B. cereus H.1 and H.2 and B. thuringiensis Kurstaki HD1, Alesti and Aizawai juroi by immunoblot analysis. These results indicated that the common antigenic epitope of the 61-kDa protein existed in the flagella both of B. cereus and B. thuringiensis .     

New Plasmid-Mediated Phosphorylation of Gentamicin C in Staphylococcus aureus

A clinical isolate of Staphylococcus aureus resistant to gentamicin, kanamycin and 3′,4′-dideoxykanamycin B contained two enzymes capable of inactivating gentamicin, i.e., an aminoglycoside 2″-phosphotransferase and aminoglycoside acetyltransferase.     

Methylation of c-myc gene changes in human lymphoproliferative diseases

The degree of methylation at the c-myc proto-oncogene was found to change in human lymphoproliferative diseases, when examined using a methylation-sensitive restriction enzyme. In peripheral blood mononuclear cells (PBMC) c-myc DNA showed hypomethylation in human lymphoproliferative diseases, in comparison to normal subjects matched in age and sex. In cases of chronic lymphocytic leukemia (CLL), the change was amplified in the crisis. When the DNA was examined at the actin gene, no significant change was observed. The results suggest that the change in c-myc proto-oncogene methylation might become an important clue in understanding the relationship between levels of gene expression and methylation in human lymphoproliferative diseases.     

Activation of mouse peritoneal macrophages by synthetic glyceroglycolipid liposomes

Summary Liposomes composed of chemically synthesized glyceroglycolipids, such as 1,2-dipalmityl-[-cellobiosyl-(1 3)]-glycerol (Cel-DAG), 1,2-dipalmityl-[-lactosyl-(1 3)]-glycerol, or 1,2-dipalmityl-[-maltosyl-(1 3)]-glycerol, were found to enhance protective immunity against transplantable tumor cells (sarcoma 180) in ICR mice. Peritoneal exudate cells prepared from mice treated in vivo with Cel-DAG showed cytostatic activity in vitro against the mouse leukemia cell line, EL-4. Adherent cells separated from this preparation showed similar activity. Peritoneal cells from polypeptone-injected mice acquired appreciable cytostatic activity when incubated in vitro in the presence of glyceroglycolipid liposomes. The adherent cell fraction alone showed rather weak cytostatic activity when pretreated with the glyceroglycolipids, and full activity was restored by supplementing with the nonadherent cell fraction. The ability of glycolipids to induce tumoricidal effects was affected by cholesterol content: with increasing cholesterol content, the activities decreased. Cholesterol-free glycolipid liposomes were taken more efficiently by macrophages than cholesterol-containing liposomes. Cholersterol modifies the surface property of glyceroglycolipid liposomes. Activation of macrophages is responsible for enhancement of protective immunity against tumor cells by injection of these glycolipids in vivo.This work was supported in part by Grants-in-Aid (Nos. 58010010, and 59870076) for Scientific Research from the Ministry of Education, Science and Culture of Japan     

Exon-intron organization, expression, and chromosomal localization of the human motilin gene

The human motilin gene has been isolated and characterized. The gene spans about 9 kilobase pairs (kb) and the 0.7 kb motilin mRNA is encoded by five exons. The 22-amino-acid motilin sequence is encoded by exons 2 and 3. The human motilin gene was mapped to the p21.2----p21.3 region of chromosome 6 by hybridization of the cloned cDNA to DNAs from a panel of reduced human-mouse somatic cell hybrids and by in situ hybridization to human prometaphase chromosomes. RNA blotting using RNA prepared from various regions of the human gastrointestinal tract revealed high levels of motilin mRNA in duodenum and lower levels in the antrum of the stomach; motilin mRNA could not be detected by this procedure in the esophagus, cardia of the stomach, descending colon or gallbladder.     

Analysis and separation of synaptosomal membrane proteins

Synaptosomal membrane proteins solubilized with 8% CHAPS-8 M urea were analyzed with twodimensional electrophoresis (2DE). The membrane proteins were resolved up to 250 spots on a 2DE map, ranging in isoelectric points (pI) from 3.5 to 10.0 and molecular weights (MW) from 10 kDa to 200 kDa. Comparison of the mapped proteins of synaptosomal membranes with those of myelin and mitochondorial membranes revealed that synaptosomal membrane proteins were characteristic in the area of pI from 4.0 to 7.5 and MW from 20 kDa to 130 kDa, and that at least 30 spots were synaptosomal membrane-specific proteins. Most of these 30 proteins have not been previously described, named, and characterized Serial numbers (from SY1 to SY30) were assigned to the proteins on the map in order to investigate them systematically. A preliminary attempt to separate synaptosomal membrane proteins was carried out using a reversed-phase HPLC system. Several proteins could either be isolated or enriched. SY10 (pI 4.6; MW 56 kDa) was one of these proteins, and was of particular interest for its unusual behavior on the reversed-phase column, and for its binding to an immobilized protein A-gel.