The in vivo synthesis and accumulation of lectin in developing seeds of black gram (Vigna mungo L. Hepper).

Black gram (Vigna mungo L. Hepper) seed contains two D-galactose-specific lectin species, BGL-I and BGL-II, identified on the basis of elution from ion exchange column and immunochemical cross-reactivity. BGL-I consisted of two monomeric lectins, BGL-I-1 and BGL-1-2, of relative molecular weights 94 and 89 kDa, respectively. BGL-II is another monomeric lectin with a molecular weight of 83 kDa. The in vivo synthesis studies using pulse-chase experiment showed that BGL-II lectin was synthesized as early as 14 days after flowering (DAF). The 94-kDa BGL-I-1 lectin was synthesized around 17 DAF. There was no cotranslational or posttranslational modification of the lectin proteins. The amount of lectin in developing seeds was determined by radial immunodiffusion assay technique. The maximum amount of lectin per seed was found at 28 DAF.

Potential for rhizofiltration of uranium using hairy root cultures of Brassica juncea and Chenopodium amaranticolor.

Hairy root cultures of Brassica juncea and Chenopodium amaranticolor were developed by genetic transformation using Agrobacterium rhizogenes. The stable, transformed root systems demonstrated a high growth rate of 1.5-3.0 g/g dry weight/day in Murashige and Skoog medium. In the present study, hairy root system was used for removal of uranium from the solution of concentration up to 5,000 microM. The results indicated that the hairy roots could remove uranium from the aqueous solution within a short period of incubation. B. juncea could take up 20-23% of uranium from the solution containing up to 5,000 microM, when calculated on g/g dry weight basis. C. amaranticolor showed a slow and steady trend in taking up uranium, with 13% uptake from the solution of 5,000 microM concentration. Root growth was not affected up to 500 microM of uranium nitrate over a period of 10 days.

Purification and characterization of a lectin from wild sunflower (Helianthus tuberosus L.) tubers.

A lectin (HTTL) was isolated from Helianthus tuberosus L. (wild sunflower) tubers using ion-exchange chromatography, gel filtration, and affinity chromatography. The lectin agglutinated both untreated and trypsin-treated rabbit erythrocytes and did not agglutinate human blood cells of groups A, B, and O. The gel filtration showed the native molecular mass of 72 kDa and subunit molecular masses of 17 and 18.5 kDa on 12% SDS-PAGE. The lectin activity was inhibited by D-mannose. The tetrameric protein revealed a unique characteristic by forming a broad zone of protein in native PAGE at pH 8.3, which dissociated into seven subunits of varying e/m ratios on acid gel at pH 4.3. These seven bands revealed two polypeptide species of molecular masses 17 and 18.5 kDa on 12% SDS-PAGE, as in the case of the native protein. The result indicated that of the seven subunits, three were homotetramers of 17 kDa, one was a homotetramer of 18.5 kDa, and three were heterotetramers of 17 and 18.5 kDa. The lectin was thermostable with broad pH optima (pH 4-8) and had no requirement for divalent metal cations for its activity. The amino acid composition showed that the lectin contained higher amounts of glycine, alanine, and lysine, but no methionine. The sugar content was estimated to be 5.3% mannose equivalent. The HTTL was mitogenic to mouse spleen (total) cells at 25 microg/ml concentration. The lectin showed characteristics different from those of the earlier reported H. tuberosus tuber lectins and hence opens up a new avenue to investigate the structure-function relationship of lectin in Helianthus species.

Purification and characterization of a hemagglutinin isolated from the leaves of Chenopodium (Chenopodium amaranticolor).

A hemagglutinin was isolated and purified from the leaves of Chenopodium (Chenopodium amaranticolor) using ion-exchange chromatography and affinity chromatography on fetuin-agarose matrix. It agglutinated rabbit erythrocytes. The hemagglutinin had a native molecular mass of 58 kDa, as estimated by gel filtration and showed a single band of molecular mass of 33 kDa on SDS-PAGE. It showed hemagglutination activity over the pH range 3-12 and was found to be stable up to 70 degrees C. On isoelectrofocussing, the pI of this hemagglutinin was estimated to be 5.25. However, it was found to contain seven charge variants when isoelectrofocussing was performed in presence of 6M urea.

Characterization and biological activities of Chenopodium leaf hemagglutinin (CLH).

A hemagglutinin (CLH) having native molecular mass of 58 kDa and subunit molecular mass of 33 kDa had been purified from the leaves of Chenopodium amaranticolor. The protein agglutinated rabbit erythrocytes and no agglutination was observed with any of the groups A, B or O of human blood. The amino acid composition revealed that CLH was rich in aspartic acid, glutamic acid, glycine and phenylalanine and also significant amount of methionine. The N-terminal amino acid sequence analysis showed that CLH had no homology with any of the plant hemagglutinins studied so far. It was inactive towards human peripheral blood cells but mitogenic for mouse spleen B-lymphocytes. CLH inhibited protein synthesis in rat thymocytes at high concentration. CLH did not inhibit TMV infection of leaves indicating absence of antiviral properties.

Characteristics of two major lectins from mungbean (Vigna radiata) seeds.

Two major lectins, MBL-I and MBL-II, were purified from Vigna radiata L. seeds using ion-exchange and gel filtration chromatography techniques. MBL-I was found to be a tetramer with native M.W. of 132 kDa and subunit M.W. of 33 kDa having alpha-galactosidase activity. MBL-II consisted of two monomeric lectins with M.W. of 94 kDa and 89 kDa which were associated mainly with beta-galactosidase activity. Both MBL-I and MBL-II are D-galactose-specific lectins.

Purification and characterization of variant alcohol dehydrogenase isozymes from durum wheat.

Three alcohol dehydrogenase (ADH) isozymes from embryos of the durum wheat cultivar Bijaga Yellow having the variant Adh-Alb allele were purified using (NH4)2SO4 precipitation, gel filtration, and ion-exchange chromatography. ADH is a dimeric enzyme. The variant isozyme ADH-1-1, which is a homodimer composed of alpha b monomers, was compared with ADH-1-5 (homodimer composed of beta a monomers), the product of Adh-B1, and the ADH-1-3 isozyme (alpha b beta a heterodimer) on a number of parameters including Km, substrate specificities, and molecular weights. No appreciable differences among the three isozymes were found, except for the faster electrophoretic mobility of alpha b alpha b dimers (ADH-1-1). The results indicate that the variant isozyme is the result of a mutation altering only the charge of the isozyme.

Two NAD-dependent alcohol dehydrogenases (E.C. 1.1.1.1) in callus cultures of wheat, rye and triticale.

Two NAD-dependent alcohol dehydrogenases ADH-1 and ADH-2, under independent genetic control of genes designated as Adh-1 and Adh-2 located on chromosomes 4A, 4B and 4D, have been reported in aestivum wheat (Hart 1980). Only ADH-1 is expressed in developing seeds, dry seeds, pollen and germinating seedlings. ADH-2 can be induced in seedling roots or shoots under conditions of partial anaerobiosis or by certain chemicals. Expression of ADH-1 and ADH-2 isoenzymes was investigated in undifferentiated calli from aestivum and durum wheats, rye, triticale and also in in vitro regenerated roots and leaves from aestivum cultures. Wheat callus cultures originating from seed, mature and immature embryos, mesocotyl and root, as well as cultures grown on media containing different supplements did not show any variation in the overall expression of ADH-1 or ADH-2, although differences in the band intensities were observed. The callus isoenzyme pattern was similar to that observed in roots under anaerobic conditions. Both ADH-1 and ADH-2 were expressed in in vitro regenerated roots but were absent in regenerated leaves. Expression of ADH-1 and ADH-2 in wheat calli seems to be related to the type of differentiation.