Isolation and properties of a lectin from the seeds of Mimosa invisa L.

A lectin has been purified from the seeds of Mimosa invisa L. by gel filtration and preparative Polyacrylamide gel electrophoresis. The purified lectin was homogeneous as judged by analytical Polyacrylamide gel electrophoresis, immunodiffusion and Immunoelectrophoresis. The apparent molecular weight is 100,000; the protein is a tetramer with two types of subunits (molecular weight 35,000 and 15,000). The lectin is a glycoprotein with approximately 21% carbohydrate and interacts with Sephadex and concanavalin ASepharose. It agglutinates erthrocytes non-specifically, does not agglutinate leucocytes and is not mitogenic, agglutinates Mimosa-nodulating Rhizobium and is a panagglutinin; the agglutination is not inhibited by several simple sugars. It is thermo-stable and has no metal ions.

RNA polymerase activity in isolated nuclei of Nicotiana sanderae callus: Characteristics and modulation during differentiation.

Isolated nuclei from differentiating cultures of Nicotiana sanderae showed increased levels of RNA polymerase activity as compared to the nuclei from callus cultures. The RNA synthetic activity was dependent on nucleotide triphosphates and Mg2+ and was destroyed by RNase. Maximum activity was obtained in the presence of 50 mM (NH4)2 SO4 and α-amanitin inhibited 40% and 55% of the activity in the nuclei from callus and differentiating tissue respectively. The nuclei from differentiating tissue elicited a 3-fold increase in RNA polymerase I and a 4-fold augmentation in RNA polymerase II activities.

Effect of phytohormones on nuclear RNA synthesis in germinating seeds of Trigonella foenumgraeceum and its callus.

Treatment of Trigonella foenumgraeceum (fenugreek) seedlings with naphthalene acetic acid plus gibberellic acid enhanced the RNA synthesising capacity of nuclei isolated from the hypocotyl and cotyledonary regions. This increase was more pronounced in the nuclei from the hypocotyl region than from the cotyledonary region. In vitro addition of these phytohormones did not stimulate RNA synthesis by nuclei. The RNA synthesis by mitochondria was not affected by preincubating the seedlings with the hormones. The nuclei isolated from callus cultures of fenugreek hypocotyl treated with the hormone also showed increased RNA synthesis.