Plant regeneration in callus and suspension cultures of Brassica campestris cv. Yellow Sarson

Prolific shoot bud differentiation was induced in callus and suspension cultures of hypocotyl origin in Brassica campestris cv. Yellow Sarson on MS medium supplemented with K (13.9–23.2 M) or BA (13.3–22.1 M). Plantlets were obtained by rooting the in vitro differentiated shoots. Histological studies revealed a unique mode of meristemoid formation.Abbreviations MS Murashige and Skoog (1962) - 2,4-D 2,4-dichlorophenoxyacetic acid - BA Benzyladenine - IAA Indole-3-acetic acid - IBA Indolebutyric acid - K Kinetin - NAA Naphthalene acetic acid     

Influence of a carbamate pesticide on growth,respiration (14C)-carbon metabolism and symbiosis of aRhizobium sp.

Summary Addition of aldicarb (2 methyl-2(methyl thio) propionaldehyde-0-methyl carbamoyl oxime) in the growth medium enhanced the growth ofRhizobium sp. (cowpea group) at 2 ppm level while an inhibition was observed at the normal (5 ppm) and higher (10 ppm) concentrations. Respiration of the cells was also inhibited by 5 and 10 ppm levels of the chemical eventhough a stimulation was observed at 2 ppm (lower) concentration. The insecticide, when incorporated at 5 and 10 ppm levels in the medium increased the¹⁴C-glucose incorporation and considerably altered the assimilation of the radioactive carbon in different fractions of rhizobium cells. Soil application of this insecticide (Temik 10 G) reduced the number of nodules formed and the total nitrogen content in cowpea plants inoculated with theRhizobium sp. but enhanced the dry matter production of cowpea plants.Based on the M. Sc. thesis submitted by the first author to the Tamil Nadu Agricultural University, Coimbatore-3.     

Regulation of glutamine synthetase I fromRhizobium meliloti

Glutamine synthetase I fromRhizobium meliloti was found to be inhibited by adenosine 5-monophosphate, alanine, glycine, carbamyl phosphate, cytidine 5-triphosphate, tryptophan, histidine, and glucosamine-6-phosphate. Each inhibitor was independent in its action and the effect was cumulative when more than one inhibitor was added.     

Precipitation of submicron charged particles in human lung airways

Precipitation of charged particles in a tube by their own space charge is investigated theoretically, when the number density of the particles is large enough so that the potential is a smooth function given by Poisson’s equation, and when the number density is small so that only the image force is important. These two approaches have been applied to the data given by Weibel for the human lung, to determine the deposition probabibilities at different generations for submicron particles when the particle density is 1×10⁵ particles/cm³. The results indicate that the electrostatic dispersion can only lead to a small effect on the lung deposition, the predominant effect is due to the image force exerted on the particles.     

In vitro differentiation in callus cultures of moth bean,Vigna aconitifolia (JACQ) marechal

Callus cultures of two cultivars of Vigna aconitifolia (IPCMO-926, RDM-120) were raised and their growth and differentiation studied. In IPCMO-926 callus cultures, numerous shoot buds differentiated on MS medium with BA (0.4–22.2 μM) alone or in combination with IAA (5.7 μM). In RDM-120 best differentiation of shoot buds was observed on a medium with K (23.2 μM) and IAA (5.7 μM). Kinetin alone, however, induced rhizogenesis in callus cultures. In suspension cultures of IPCMO-926 embryoids differentiated on MS medium with K (0.5 μM) and 2,4-D (0.4 and 0.9 μM).     

Effect of oilseed cakes on alpha-amylase production by Bacillus licheniformis CUMC305.

The effects of oilseed cakes on extracellular thermostable alpha-amylase production by Bacillus licheniformis CUMC305 was investigated. Each oilseed cake was made of groundnut, mustard, sesame, linseed, coconut copra, madhuca, or cotton. alpha-Amylase production was considerably improved in all instances and varied with the oilseed cake concentration in basal medium containing peptone and beef extract. Maximum increases were effected by a low concentration (0.5 to 1.0%) of groundnut or coconut, a high concentration (3%) of linseed or mustard, and an Rintermediate concentration (2%) of cotton, madhuca, or sesame. The oilseed cakes made of groundnut or mustard could completely replace the conventional peptone-beef extract medium as the fermentation base for the production of alpha-amylase by B. licheniformis. The addition of corn steep liquor to cotton, linseed, sesame, or madhuca cake in the medium improved alpha-amylase production.     

Interaction of the carboxamide of NADPH with Lactobacillus casei dihydrofolate reductase

Dihydrofolate reductase from Lactobacillus casei and its complexes with NADPH and methotrexate yield well-resolved Raman spectra. The 1685-cm^?1 Raman band assigned to the carboxamide of NADPH persists in the NADPH-enzyme binary complex but is absent from the NADPH-methotrexate-enzyme ternary complex. This is ascribed to stabilization of the polarized form of the carboxamide by H bonding to the NH and CO groups of Ala 6 and Ile 13 of the peptide backbone.     

Nonradioactive in situ localization of poly(A)+ RNA during pollen development in anthers of tobacco (Nicotiana tabacum L.)

Summary A method is described for non-radioactive labeling of total mRNA [poly(A)+ RNA] in plastic-embedded plant tissue sections. Oligo-deoxythymidylic acid (oligo-dT) labeled with digoxigenin-conjugated dUTP was used for in situ hybridization to poly(A)+ RNA in sections of tobacco (Nicotiana tabacum) anthers. The digoxigenin was immuno-stained using antidigoxigenin IgG and gold-labeled protein-A, followed by silver enhancement of the gold label. Reproducibly similar positive staining patterns were obtained with digoxigenin-labeled oligo-dT and polyuridylic acid [poly(U)], but not with a similarly labeled sense probe, poly(A). In the developing anthers, from the onset of meiosis to the production of pollen grains, labeling patterns were compatible with a gradual depletion of nuclear and chromosome-associated sporophytic mRNA molecules during prophase of meiosis, followed by postmeiotic production of gametophytic mRNA in microspore nuclei and the vegetative nuclei of the pollen grains.Abbreviations BSA bovine serum albumin - DIG digoxigenin - IgG immunoglobulin-G - oligo-dT oligo-deoxythymidylic acid - PAS-ABB periodic acid Schiff-aniline blue black - PBS phosphate buffered saline - poly(A) polyadenylic acid - poly(U) polyuridylic acid - SSC standard saline citrate