Molecular heterogeneity of Cowpea (Vigna unguiculata Fabaceae) seed storage proteins

81 wild forms and 110 cultivated cowpea,Vigna unguiculata, accessions from 21 countries of Africa were screened for variability in seed storage proteins. Total seed proteins, albumin and globulin fractions were investigated by means of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing (IEF) of nonreduced and/or reduced samples in one- and two-dimensional procedures. The globulin fraction is heterogeneous in molecular weight and contains both legumin-like components and three to six nondisulfide-linked subunits. Three globulin subunits, with molecular weights 110, 76, and 41 kD were found to be composed of disulfide-linked polypeptides. In the nondisulfide-linked fraction, both cultivated and wild forms exhibited patterns of four types (A–D). This fraction contains polypeptide subunits of molecular weights 62, 56, and 52 kD for A type, 62, 56, 54, and 52 kD for B type, 62, 56, 52, and 50 kD for C type, and at least 62, 56, 54, 52, 50, and 49 kD for D type. These subunits present similar multiple charge forms but C and D types possess more basic specific 50 and 49 kD nondisulfide linked components. Major albumin fraction contains subunits of 94, 86, 32, and 24kD. No infraspecific variation was observed in albumin or legumin-like fractions. The discussion is focussed on the relations between genetic variability assessed by storage protein coding genes and phenotypic variability.     

Pentosan polysulfate,a potent anti HIV and anti tumor agent,inhibits protein serine/threonine and tyrosine kinases

The effect of nicotinamide-adenine dinucleotides (NAD⁺ and NADP⁺) on Ca²⁺ transport in rat liver nuclei was investigated. Ca²⁺ uptake and release were determined with a Ca²⁺ electrode. Ca²⁺ uptake was dependent on adenosine triphosphate (ATP; 2mM). The presence of NAD⁺ (2mM) or NADP⁺ (1 and 2mM) caused a significant inhibition of Ca²⁺ uptake following addition of 2mM ATP. Ca²⁺, which accumulated in the nuclei during 6 min after ATP addition, was significantly released by the addition of NAD⁺ (0.5–2mM) or NADP⁺ (0.1–2mM). However, the effect of NADH (2mM) or NADPH (2mM) on Ca²⁺ uptake and release clearly weakened in comparison with the effects of NAD⁺ and NADP⁺. Meanwhile, ryanodine (10M), thapsigargin (10M) or oxalate (0.5mM) had no effect on Ca²⁺ uptake and release in rat liver nuclei. These reagents did not significantly alter the effects of 2mM NAD⁺ on Ca²⁺ uptake and release. Thus, NAD⁺ and NADP⁺ had a potent effect on Ca²⁺ transport in rat liver nuclei. The present findings suggest that the liver cytosolic NAD⁺ (NADP⁺) is a factor in the regulation of the nuclear Ca²⁺ concentration. (Mol Cell Biochem121: 127–133, 1993)     

Effect of Organic Acids on Reactions Catalyzed by Manganese Peroxidase from Phanerochaete chrysosporium

The effect of several organic acids on the oxidation of Mn(II) catalyzed by manganese peroxidase was studied. Reactivities of manganese peroxidase and chemically prepared Mn(III) organic acid complexes towards phenolic compounds were compared. If lactate appears to be the best complexant for manganese peroxidase activity, chemically prepared Mn(III)—lactate complex is a less effective oxidant towards phenolic compounds than other Mn(III)—complexes. Our results agree with the hypothesis that certain organic acids are involved in the catalytic cycle of manganese peroxidase. Malonate and lactate seem to be the most attractive complexants for practical applications of manganese peroxidase and were used in enzymatic treatment of hardwood kraft pulp. Bleaching of kraft pulp was studied and after alkaline extraction, a significant decrease of kappa number was measured. The bleaching was enhanced in lactate buffer.     

The gene coding for the α1 subunit of the skeletal dihydropyridine receptor (Cchl1a3=mdg) maps to mouse Chromosome 1 and human 1q32

Using both chromosomal in situ hybridization and molecular techniques, we report the genetic localization of the gene coding for the alpha 1 subunit of the skeletal slow Ca²⁺ current channel/DHP receptor gene (Cchl1a3) on human Chromosome (Chr) 1 (1q31–1q32 region) and on mouse Chr 1 region (F-G). On the basis of single-strand conformation polymorphism (SSCP-PCR) analysis in an interspecific backcross, we have determined that the Cchl1a3=mdg (muscular dysgenesis) locus is very closely linked to the myogenin (Myog) locus.     

Fine genetic mapping of the proximal part of mouse Chromosome 2 excludes Pax-8 as a candidate gene for Danforth's short tail (Sd)

Danforth's short tail (Sd) is a semidominant mutation of the mouse with effects on the skeleton and the urogenital system. In view of its phenotype and its position in the proximal part of Chromosome (Chr) 2, three genes qualified as possible candidates: Pax-8, a paired box-containing gene; Midkine (Mdk), a retinoic acid-responsive gene; and a new locus (Etl-4) identified by enhancer trapping with a lacZ reporter gene which showed expression in the notochord, the mesonephric mesenchyme, and the apical ectodermal ridge. Three different backcrosses involving all three genes in different combinations were set up and analyzed. From our results we conclude that Sd, Etl-4, Pax-8, and Mdk are independent loci, with Etl-4 being the closest genetic marker (1.1±1.4 cM) to the Danforth's short tail (Sd) gene.     

Mouse chromosome 19

Chair of Committee for Mouse Chromosome 19     

Further progress towards a catalogue of all Arabidopsis genes: analysis of a set of 5000 non-redundant ESTs

Nearly 7000 Arabidopsis thaliana -expressed sequence tags (ESTs) from 10 cDNA libraries have been sequenced, of which almost 5000 non-redundant tags have been submitted to the EMBL data bank. The quality of the cDNA libraries used is analysed. Similarity searches in international protein data banks have allowed the detection of significant similarities to a wide range of proteins from many organisms. Alignment with ESTs from the rice systematic sequencing project has allowed the detection of amino acid motifs which are conserved between the two organisms, thus identifying tags to genes encoding highly conserved proteins. These genes are candidates for a common framework in genome mapping projects in different plants.     

A novel wound-inducible extensin gene is expressed early in newly isolated protoplasts of Nicotiana sylvestris

A cDNA clone (6PExt 1.2) encoding a novel extensin was isolated from a cDNA library made from 6 h old mesophyll protoplasts of Nicotiana sylvestris. The screening was performed with a heterologous probe from carrot. The encoded polypeptide showed features characteristic of hydroxyproline-rich glycoproteins such as Ser-(Pro)₄ repeats and a high content in Tyr and Lys residues. The presence of four Tyr-X-Tyr-Lys motifs suggests the possibility for intramolecular isodityrosine cross-links whereas three Val-Tyr-Lys motifs may participate in intermolecular cross-links. The analysis of genomic DNA gel blots using both the N. sylvestris and the carrot clones as probes showed that the 6PExt 1.2 gene belongs to a complex multigene family encoding extensin and extensin-related polypeptides in N. sylvestris as well as in related Nicotianeae including a laboratory hybrid. This was confirmed by the analysis of RNA gel blots: a set of mRNAs ranging in size from 0.3 kb to 3.5 kb was found by the carrot extensin probe. The 6PExt 1.2 probe found a 1.2 kb mRNA in protoplasts and in wounded tissues as well as a 0.9 kb mRNA which seemed to be stem-specific. The gene encoding 6PExt 1.2 was induced by wounding in protoplasts, in leaf strips and after Agrobacterium tumefaciens infection of stems.