A Novel Class of Herbicides (Specific Inhibitors of Imidazoleglycerol Phosphate Dehydratase)

A new mode of herbicidal action was established by finding specific inhibitors of imidazoleglycerol phosphate dehydratase, an enzyme of histidine (His) biosynthesis. Three triazole phosphonates inhibited the reaction of the enzyme with Ki values of 40 [plus or minus] 6.5, 10 [plus or minus] 1.6, and 8.5 [plus or minus] 1.4 nM, respectively, and were highly cytotoxic to cultured plant cells. This effect was completely reversed by the addition of His, proving that the cytotoxicity was primarily caused by the inhibition of His biosynthesis. These inhibitors showed wide-spectrum, postemergent herbicidal activity at application rates ranging from 0.05 to 2 kg/ha.     

Idiotypic diversity and variable region gene usage by mouse anti-HLA-DQ3 mAb

The anti-HLA-DQ3 monoclonal antibodies (mAb) KS13, SO1, SO2, SO3, SO4, and SO5 recognize spatially close but distinct antigenic determinants, since they crossinhibit each other in their binding to HLA-DQ3 antigens, but do not share idiotopes recognized in their antigen combining site by syngeneic and anti-id antisera and mAb. Furthermore, mAb SO1, SO3, SO4, and SO5 react also with HLA-DQ allospecificities other than HLA-DQ3. Sequence analysis of the heavy (V _H ) and light (V _L ) chain variable region of the six mAb revealed preferential usage of V _H 36–60 and V _K 12/13 gene families. However, the individual V _H and V _L germline gene usage by the six mAb is diverse and the utilization of D, J _H , and J _L gene segments is heterogeneous. The diverse usage of V _H and V _L gene segments and heterogeneous amino acid sequences of V _H and V _L CDR, together with the heterogeneous idiotypic profile, may reflect the complexity of the determinants recognized by the six mAb on HLA-DQ3 antigens. The results we have presented provide for the first time information about the structural basis of the diversity of antibodies recognizing human histocompatibility antigens.The nucleotide sequence data reported in this Papershave been submitted to the GenBank nucleotide sequence database and have been assigned the accession numbers L20499, L20957, L20961, L24557, L24558 and L20962, respectively, for V _H region genes, and L20956, L20958, L24555, L24556, L20959, and L20960, respectively, for V _L region genes     

Nucleotide sequence of a Sendai virus genome region covering the entire M gene and the 3'' proximal 1013 nucleotides of the F gene.

We determined the sequence of the 2,138 nucleotides in the Sendai virus genome just following the 3' proximal 3,686 nucleotides which we had previously reported (Nucleic Acids Res. 11, 7317-7330, 1983). This covers the entire third gene of 1,173 nucleotides and the 3' proximal 1,013 nucleotides of the fourth gene. Like the NP and P+C genes, both the third and fourth genes start from consensus sequence R1 (3'-UCCCAC(or UA)UUUC) at the 3' end and the third gene terminates with consensus sequence R2 (3'-AUUCUUUUU) at the 5' end. The third gene was identified as M, and the deduced 348 amino acids indicated that the M protein is rich in basic residues and has hydrophobic domains near the C-terminal. The fourth gene, although sequencing is not complete yet, was identified as F, since a large open reading frame found in the gene contains the characteristic sequence of 20 amino acids located at the N-terminal of the F1 protein. Analyses of the amino acid sequence suggested that the structure of the F gene product is NH2-signal peptide-F2-F1-COOH.     

Volatile components of Artemisia capillaris

Terpenoid and acetylenic components not reported previously in Artemisia capillaris have been identified, including p-cymene, 5-phenyl-1, 3-diyne, dehydrofalcarinone and dehydrofalcarinol. The distribution of volatile components in different parts of the plant is described.     

Interaction of subunits of polypeptide chain elongation factor I from pig liver. Formation of EF-1alpha.EF-1betagamma and EF-1beta complexes

In the preceding papers, we showed that one of the two complementar factors of polypeptide chain elongation factor 1 (EF-1) from pig liver, EF-1alpha, functionally corresponds to bacterial EF-Tu (Nagata, S., Iwasaki, K., and Kaziro, Y. (1976) Arch. Biochem. Biophys. 172, 168), while the other, EF-1betagamma, as well as one of its subunits, EF-1beta, corresponds to bacterial EF-Ts (Motoyoshi, K. and Iwasaki, K. (1977) J. Biochem. 82, 703). Therefore, the interaction between EF-1alpha and EF-1 betagamma or EF-1beta was was examined and the following results were obtained. i) EF-1betagamma catalytically promoted the exchange of [14C]GDP bound to EF-1alpha with exogenous [3H]GDP. ii). In the absence of the exogenous guanine nucleotide, EF-1betagamma as well as EF-1beta could displace GDP bound to EF-1alpha to form an EF-1alpha.EF-1betagamma as well as an EF-1alpha.EF-1beta complex. iii) The occurrence of EF-1alpha.EF-1betagamma and EF-1alpha.EF-1beta complexes was demonstrated by gel filtration on Sephadex G-150. These results strongly indicate that the mechanism of the action of EF-1betagamma or EF-1beta in converting EF-1alpha.GDP into EF-1alpha.GTP is analogous to bacterial EF-Ts, and the reaction is accomplished by the following reactions; EF-1alpha.GDP + EF-1betagamma (or EF-1beta) in equilibrium EF-1alpha.EF-1betagamma (or EF-1beta) + GDP; EF-1alpha.EF-1beta (or EF-1beta) + GTP IN EQUILIBRIUM EF-1alpha.GTP + EF-1betagamma (or EF-1beta).     

Characterization of a Xenopus laevis skin peptidylglycine alpha-hydroxylating monooxygenase expressed in insect-cell culture.

The C-terminal amide structure of peptide hormones and neurotransmitters is synthesized via a two-step reaction catalyzed by peptidylglycine alpha-hydroxylating monooxygenase (PHM) and peptidylhydroxyglycine N-C lyase. A Xenopus laevis PHM expressed in insect-cell culture by the baculovirus-expression-vector system was purified to homogeneity and characterized. Using a newly established assay system for PHM, the kinetic features of this enzyme were investigated. As expected, the enzyme required copper ions, L-ascorbate and molecular oxygen for turnover. Salts like KI and KCl, and catalase stabilized the enzyme in the presence of L-ascorbate. The optimum pH value for the enzyme reaction was around six when Mes buffer was used and around seven when phosphate buffer was used under the same assay condition. Below pH 6, acetate, iodide and chloride ions activated the reaction. The kinetic analysis is consistent with a ping-pong mechanism with respect to peptide and L-ascorbate, and the peptide showed substrate inhibition. The substrate specificity of the enzyme at the penultimate position was examined by competitive assay using tripeptides with glycine at the C-termini and the inhibitory potency of these peptides in descending order was methionine > aromatic > non-polar amino acids.     

Herbimycin A blocks IL-1-induced NF-kappa B DNA-binding activity in lymphoid cell lines.

The mechanism by which interleukin-1 alpha (IL-1 alpha) activates NF-kappa B DNA-binding activity is not completely understood. While it is well established that protein kinase C can activate NF-kappa B, neither protein kinase C nor protein kinase A appears to be critical in the induction of NF-kappa B by IL-1 alpha. Since a number of growth factors signal via protein tyrosine kinase, in this study we examined a possible involvement of protein tyrosine kinase in the IL-1 alpha-induced NF-kappa B. The results showed that in the murine pre-B cell line 70Z/3 and in the murine T cell line EL-4 6.1 C10 IL-1 alpha-induced NF-kappa B was associated with transient increase in protein tyrosine kinase activity. Pre-treatment of these cell lines with herbimycin A, an inhibitor of tyrosine kinase activity, blocked the IL-1 alpha-enhanced protein tyrosine kinase activity and the IL-1 alpha-induced NF-kappa B DNA-binding activity. Herbimycin A at concentrations sufficient to block IL-1 alpha-induced NF-kappa B did not block the phorbol 12-myristate 13-acetate (PMA)-induced NF-kappa B. The data suggest that IL-1 alpha and PMA activate NF-kappa B by different pathways and that induction of NF-kappa B DNA-binding activity by IL-1 might be dependent on protein tyrosine phosphorylation.     

Two Types of Channels Involved in the Malate Ion Transport across the Tonoplast of a Crassulacean Acid Metabolism Plant

Ion channels in tonoplast of leaf cells of a Crassulacean acid metabolism plant, Graptopetalum paraguayense, using the patch clamp technique were investigated. Results showed the existence of two types of channels involved in the malate ion transport across the tonoplast. One type corresponded to the slow-activating vacuolar-type (R Hedrich, E Neher [1987] Nature 329: 833-836), probably taking part in the malate efflux from vacuoles. Another showed the membrane potential-dependent channel current of malate flux over a wide range of cytoplasmic free Ca²⁺ concentration (10⁻⁸-10⁻⁵ molar), a property favoring the malate uptake. This type seems to be different from the fast-activating vacuolar-type.