Abbagani Sadanandam

MICROPROPAGATION OF TERMINALIA BELLIRICA ROXB. – A SERICULTURE AND MEDICINAL PLANT

SummaryA protocol for micropropagation of plants via axillary bud proliferation from nodal explants of Terminalia bellirica Roxb. seedlings has been established. Explants were cultured on Murashige and Skoog medium with different concentrations of 6-benzyladenine (BA; 4.4, 8.9, 13.3, 17.8, or 22.2 μM) or kinetin (Kn; 4.6, 9.3. 14.0, 18.6, or 23.2 μM). Within the range evaluated, the medium containing 13.3 μM BA showed the highest shoot length (1.9=0.2 cm) in the primary culture. When separated and transferred to fresh subculture medium with lower levels of BA (2.2. 4.4, 6.6, or 8.9 μM) or Kn (2.3, 4.6, 6.9, or 9.3 μM), the nodal segments from individual regenerants (obtained initially from seedling nodes) showed efficient shoot induction at 4.4 μM BA. Rooting of the shoots was achieved under in vitro conditions on two media tested, i.e., modified Gamborgs (B5) medium or Woody Plant Medium, both supplemented with 4.9 μM indole-3-butyric acid. Regenerated plants were established in the greenhouse.

Molecular docking studies and in vitro screening of new dihydropyridine derivatives as human MRP1 inhibitors

The overexpression of multidrug resistance protein 1 (MRP1) by tumor cells results in multidrug resistance (MDR) to structurally unrelated anticancer drugs. Circumvention of MDR by combination of chemosensitizers with antitumor compounds is a new field of investigation in cancer chemotherapy. Much effort has been put-in recently to identify the modulators/inhibitors of MRP1 to overcome the MDR. 1,4-Dihydropyridine (DHP) derivatives are indicated to be a new class of MRP1 inhibitors in cancer treatment. Molecular docking studies were carried out on 48 newly synthesized DHP derivatives with the crystal structure of MRP1 to gain some structural insights on the binding mode and possible interactions with the active site of MRP1 (NBD1). The 10 top-ranked molecules were selectively evaluated, experimentally for their MRP1 inhibitory effect using the insect cell membrane MRP1 ATPase assay. The inhibitory capacity (IC(50) concentrations) of the test compounds was compared with the reported IC(50)- or the K(i)-concentrations for benzbromarone, a standard MRP1 inhibitor. Amongst the compounds tested, compounds IA(1) and IIA(5) were found to exhibit a potent MRP1 inhibitory action with IC(50) values of 20±4 and 14±2 μM (mean±SD), respectively as compared to benzbromarone (IC(50)=4 μM). The compound IIA(5), in particular was found to be more potent than IA(1) in accordance with the docking results. These new DHP derivatives possess promising characteristics for their development as MDR reversal agents.

Induction of atrazine resistance and somatic embryogenesis in Solanum melongena

Abstract The effects of atrazine on cotyledon cultures of Solanum melongena were investigated with a view to establishing a system for in vitro selection of resistant mutants. At herbicide levels producing little growth inhibition some chlorophyll loss occurred associated with the production of albino shoots. At 15 mg/l bleaching was more pronounced and was accompanied by the development of necrotic spots; however, efficient bleaching was associated with severe suppression of growth. Mutagenesis with EMS resulted in herbicide-resistant mutants based on the embryogenic ability of mutagenised explants placed on medium containing selective levels of sucrose (0.2%) and atrazine (15 mg/l). Different morphogenetic responses were observed when the levels of sucrose (0.2–5%) were altered. Somatic embryogenesis was observed at low sucrose concentrations (0.2–0.5%). Both embryogenesis and shoot regeneration occurred in 1% sucrose. Shoot regeneration was maximum in 2% sucrose and the regenerating ability decreased with a further increase in sucrose concentration (3–5%). However, lowering of sucrose concentration from 2% to 0.2% caused complete bleaching, permitting the selection of herbicide-resistant mutants.

EMS-induced streptomycin resistance in Solanum melongena.

Streptomycin-resistant mutations were induced in Solanum melongena by exposing seeds to ethyl methane sulphonate (EMS). Seed mutagenesis resulted in a high frequency of chlorophyll-deficient mutations and a low frequency of resistant shoots, both of which retained their resistance on subsequent testing. Reciprocal crosses between streptomycin-resistant and -sensitive plants showed a non-Mendelian transmission of the resistance trait. Streptomycin resistance is the first selectable and maternally inherited organelle marker described in brinjal.

Stable plastid transformation in Scoparia dulcis L.

In the present investigation we report stable plastid transformation in Scoparia dulcis L., a versatile medicinal herb via particle gun method. The vector KNTc, harbouring aadA as a selectable marker and egfp as a reporter gene which were under the control of synthetic promoter pNG1014a, targets inverted repeats, trnR/trnN of the plastid genome. By use of this heterologous vector, recovery of transplastomic lines with suitable selection protocol have been successfully established with overall efficiency of two transgenic lines for 25 bombarded leaf explants. PCR and Southern blot analysis demonstrated stable integration of foreign gene into the target sequences. The results represent a significant advancement of the plastid transformation technology in medicinal plants, which relevantly implements a change over in enhancing and regulating of certain metabolic pathways.

In silico evaluation of TERT inhibition by anticancer drugs

AbstractThe activation of telomerase represents an early step in carcinogenesis. Increased telomerase expression in malignant tumors suggests that telomerase inactivation may represent a potential chemotherapeutic target. In this work, existing anticancer drugs were docked against telomerase reverse transcriptase (TERT) using a Lamarckian genetic algorithm (LGA). Autodock’s scoring function was applied to each of the molecules in order to identify the inhibitor with the strongest pharmacological action. The structural insights provided by this study regarding binding poses and possible interactions, free energies of binding, and drug scores aided in the identification of potential inhibitory compounds. The ranks of the various ligands investigated were based on the final docked energy values. Among nine selected compounds, vindesine, temsirolimus, and cyclosporine were found to be more potent TERT inhibitors than the standard inhibitor, curcumin. FigureExisting anticancer drugs were docked against telomerase reverse transcriptase (TERT). Among nine selected compounds, vindesine, temsirolimus, and cyclosporine were found to be more potent TERT inhibitors than the standard inhibitor, curcumin

Induced Synaptic Mutant from Mesophyll Cell Protoclones of Dihaploid Solanum tuberosum

Summary A synaptic mutant showing a very abnormal meiotic chromosome pairing was individuated among plants regenerated from protoplasts treated with 0.025 % EMS, which results in an abnormally high frequency of univalents at diakinesis and metaphase I. As a consequence of univalent formation, the chiasma frequency was greatly reduced and the later stages of meiosis were highly irregular, resulting in high pollen sterility.