Micropropagation of Three Varieties of Caralluma adscendens via Nodal Explants

A procedure for in vitro propagation of pharmaceutically valuable varieties of Caralluma adscendens from nodal explant, is described. The highest shoot multiplication with 80% frequency was achieved within one month on Murashige and Skoog’s medium supplemented with 8.87 μM BA. Shoot multiplication occurred in subsequent subcultures in culture bottles on MS medium. Regenerated shoots were rooted on half strength MS medium supplemented with NAA (0.54 μM) in all the three varieties. The rooted plants were hardened for establishment in soil.     

Protein binding studies of luminescent rhenium(I) diimine complexes

Interaction of four luminescent rhenium(I) diimine complexes, [Re(CO)₃(N-N)L]PF₆ ((N-N = 2,2-bipyridine, L = py-3-COOH) 1a, (N-N = 2,2-bipyridine, L = py-3-CONH₂) 1b, (N-N = 1,10-phenanthroline, L = py-3-COOH) 2a, (N-N = 1,10-phenanthroline, L = py-3-CONH₂) 2b with bovine serum albumin (BSA) at physiological pH has been examined using UV-Vis absorption and luminescence spectroscopy, excited state lifetime measurement and circular dichroism (CD). In the presence of BSA, the luminescence of Re(I) complexes is quenched due to the locking-in of the probe into the protein environment. Interestingly the probe is released from the protein environment in the presence of sodium dodecyl sulfate (SDS) resulting in the restoration of the original luminescence along with a red shift in the emission maximum. These observations are explained in terms of binding constants (K_a) of probe with protein and surfactant and the nature of the binding has been investigated from Scatchard plot and Hill’s coefficient (n) value. These studies point out that the interaction between Re(I) complexes and BSA is cooperative in nature.     

Mass Production Potential of the Bacto-Helminthic Biocontrol Complex Heterorhabditis indica - Photorhabdus luminescens

Heterorhabditis indica is a potential agent for the biological control of grubs in sugarcane fields in India. The type strain LN 2 was transferred to monoxenic cultures on its symbiont Photorhabdus luminescens and successfully produced on solid media. In liquid cultures, a mean dauer juvenile yield of 457 000 was obtained with a maximum of 648 000 per ml. Comparatively high yields have not been reported before. Therefore, costs related to the liquid culture production of H. indica will be lower than for other entomopathogenic nematodes currently used in biocontrol. Different bacterial clones had no significant influence on the dauer juvenile yields in liquid media. The exit from the dauer juvenile stage (recovery) after inoculation and the number of hermaphrodites significantly decreased when culture temperature was increased from 25-30 ° C; the dauer juvenile yields were not affected. The cell density of P. luminescens in batch cultures was higher at 25 and 30 ° C than at growth temperatures of 35 and 37 ° C. In continuous culture, the bacterial growth was inhibited when the growth temperature reached 38 ° C. After approximately 60 h, the bacteria adapted to higher temperature and the growth rate increased again. When the temperature was further increased to 40 ° C, the bacterial growth was inhibited.     

Oxidative stress and the development of diabetic complications - antioxidants and lipid peroxidation in erythrocytes and cell membrane.

Erythrocytes isolated from 131 cases of Non-Insulin Dependent Diabetes Mellitus (NIDDM) were studied for lipid peroxidation, antioxidant defences, and the maximum peroxidisable substrate in the cell membrane. Antioxidant defences are lowered in NIDDM, followed by significant rise in lipid peroxidation products. However, in the erythrocyte membrane, the total polyunsaturated peroxidisable lipids are lower than in normal erythrocytes which may be a causative factor affecting the survival of the cells.     

Is the lactose-utilization ability ofRhizobium ofSesbania procumbens a vestigeal function?

Rhizobium SBS-R100, isolated from the stem nodules ofSesbania procumbens, synthesized -galactosidase constitutively. Transposon mutagenesis by Tn9 induced mutants defective in lactose utilization; the mutations did not interfere with growth, nodulation or N₂ fixation. Mouse monoclonal antibody raised against -galactosidase ofEscherichia coli reacted with soluble proteins of wild typeRhizobium SBS-R100. Anin vivo constructed recombinant plasmid pSBS-4 complemented aRhizobium mutant defective in lactose utilization.     

Interaction of ferredoxin with carbon monoxide dehydrogenase from Clostridium thermoaceticum.

Acetogenic bacteria, as determined with Clostridium thermoaceticum, synthesize acetate by the acetyl-CoA pathway which involves the reduction of CO2 to a methyl group and then combination of the methyl with CoA and a carbonyl group formed from CO or CO2 (Wood, H.G., Ragsdale, S.W., and Pezacka, E. (1986) Trends Biochem. Sci. 11, 14-18). Carbon monoxide dehydrogenase (CODH), the key enzyme in this pathway not only catalyzes the oxidation of CO to CO2 but also the final step, the synthesis of acetyl-CoA from a methyl group, CO, and CoA. Previously, it has been shown that ferredoxin can stimulate exchange of CO with CH3 14COSCoA (Ragsdale, S.W., and Wood, H.G. (1985) J. Biol. Chem. 260, 3970-3977). In the present study, it has been observed that ferredoxin and CODH can form an electrostatically stabilized complex. In order to identify the ferredoxin binding region on CODH, the ferredoxin and CODH were cross-linked by using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. The cross-linked CODH-ferredoxin adduct was enzymatically as active as the uncross-linked complex. The native CODH and cross-linked CODH-ferredoxin complex were subjected to cyanogen bromide cleavage. By comparison of the high-performance liquid chromatography peptide profiles, it was observed that the mobility of at least one peptide is altered in the CODH-ferredoxin cross-linked complex. The peptide was identified with residues 229-239 of the alpha-subunit of CODH.     

Preparation of cyanobacterial peptide toxin as a biopesticide against cotton pests

Glycine-rich peptide toxin of cyanobacterium Scytonema MKU 106 was purified. UV spectral analysis showed an absorption maximum at 228 nm and the molecular mass was less than 12 kDa. The mortality rate of American boll worms (Helicoverpa armigera) was about 80% and 40% 84 h after treatment with 0.001% crude and purified peptide toxins respectively; 100% mortality was observed after 108 h treatment with both purified and crude peptide toxins. The LC₅₀ (lethal concentration to 50% of the population) for Heliothis larvae after 96 h was 8.3 μg/ml purified peptide toxin and 6.2 μg/ml crude peptide toxin. Observations also show that the peptide toxin at 0.01% concentration acts as a biopesticide and at high (0.1%) concentrations it will act as an anti-feeding compound for Stylepta derogata (leaf-roller) larvae of the cotton crop. Received: 22 May 1996 / Accepted: 8 July 1996     

Studies on some trace and minor elements in blood

Blood is one of the widely used specimens for biological trace element research because of its biological significance and ease of sampling. We have conducted a study of the blood of the Kalpakkam township population for trace and minor elements. For this purpose, analytical methods have been developed and standardized in our laboratory for the elemental analysis of blood plasma and red cells. Inductively coupled plasma-mass spectrometry (ICP-MS), a relatively new technique, has been applied for the analysis of trace elements. Details regarding spectral interference and matrix interference encountered in the analysis of blood and the methods of correcting them have been discussed. Flame atomic absorption spectrometry (AAS)/atomic emission spectrometry (AES) has been applied for the determination of minor elements. Precision and accuracy of these methods have also been discussed.