Bapi Ghosh

Effectivity of copper and cadmium sulphide nanoparticles in mitotic and meiotic cells of Nigella sativa L. (black cumin) – can nanoparticles act as mutagenic agents?

ABSTRACT The present investigation deals with wet chemical preparation and characterisation of copper (Cu) and cadmium sulphide (CdS) nanoparticles (NPs) (using UV–visible spectra, Fourier transform infra-red scattering, X-ray diffraction, dynamic light scattering, field emission scanning electron microscopy and transmission electron microscopy) and their effectivity on mitotic and meiotic cells of Nigella sativa L. (Ranunculaceae) in comparison to ethyl methanesulphonate (EMS) and gamma irradiations. The objective of the study is to foresee whether Cu- and CdS-NPs can induce similar type of chromosomal aberrations as that of EMS and gamma irradiations, or not. Dry seeds of N. sativa (2n = 12) are exposed to Cu- and CdS-NPs (0.25, 0.50 and 1.0 µg/ml; 3 and 6 h), EMS (0.25, 0.50 and 1.0%; 3 and 6 h) and doses of gamma irradiations (25, 50, 100, 200 and 300 Gy). Cu-NPs (range: 25.7 to 120.4 nm; 33.2 nm ± 9.6) and CdS-NPs (range: 29.4 to 115.7 nm; 37.8 nm ± 10.7) are both cubical to spherical in shape. NPs are found to induce similar responses as that of the studied conventional mutagens, in relation to physiological and chromosomal (mitotic and meiotic) attributes. Uptake of Cu- and CdS-NPs in seedlings is also studied using atomic absorption spectroscopy. Results suggest that Cu- and CdS-NPs can act as mutagenic agent, a pioneer report of its kind.

Assessment of photocatalytic potentiality and determination of ecotoxicity (using plant model for better environmental applicability) of synthesized copper, copper oxide and copper-doped zinc oxide nanoparticles

NPs synthesis, characterization and azo-dye degradation A facile cost effective wet chemical method of synthesis is proposed for Cu-NPs, CuO-NPs and Cu-doped ZnO-NPs. The nanomaterials are opto-physically characterized for nano standard quality. Cu-doped ZnO-NPs based catalytic system is found to possess most efficient photocatalytic activity in degradation of two organic azo-dyes namely methyl red (MR) and malachite green (MG) that are released as industrial effluents in eco-environment intercollegium. Two possible photocatalytic degradation pathways are proposed to understand the mechanism of interaction prevailing during the mineralization of MR and MG dyes. Such study provides insight for waste water management. The uniqueness of the present work is 1) possible routes of MG dye degradation by Cu-doped ZnO-NPs and subsequent intermediate by-products are novel and pioneered of its kind. 2) two new intermediate byproducts are identified suggesting prevalence of multiple MR degradation pathways by Cu-doped ZnO-NPs. Assessment of ecotoxicity For assessment of residual NPs impact on environment, eco-toxicological assay is performed using plant system (Sesamum indicum L.) as model. The study encompasses seed germination, seedling morphology, quantification of endogenous H2O2 and MDA generation, estimation of DNA double strand break and analysis of cell cycle inhibition. Results highlight reduced ecotoxicity of Cu-doped ZnO-NPs compared to the other synthesized nanomaterials thereby suggesting better environmental applicability in waste water purification.

TAXONOMICAL, ANATOMICAL, CYTOLOGICAL AND PALYNOLOGICAL ASSESSMENT OF A GERMPLASM OF INDIGOFERA TINCTORIA L. (FABACEAE): AN AYURVEDIC PLANT

A germplasm of Indigofera tinctoria L. (Fabaceae, dye yielding plant with immense therapeutic importance and also with potential phytoconstituents) is grown in West Bengal plains (Nadia) and characterized taxonomically, anatomically, cytologically and palynologically. The objective of the work is to keep the germplasm under ex-situ conservation and sustainable cultivation for further genetic exploration in enhancing bioactive compounds and crop improvement.

Nanoparticle (CdS) interaction with host (Sesamum indicum L.) – its localization, transportation, stress induction and genotoxicity

ABSTRACT The present study highlights the nanoimpact of cadmium sulfide quantum dots on a plant system (Sesamum indicum L.) encompassing uptake of nanoparticles (NPs), subsequent translocation following root to leaf transportation pathway using both water- and food-conducting elements and deposition in nucleus and cytoplasm with no preferential subcellular localization. Nanocrystal agglomeration, mucilaginous sheathing and vesicularization studied are the host toxicity minimization attempt. Cellular stress due to NPs is recorded in the form of elevated production of hydrogen peroxide and malondialdehyde. However, non-synchronous activation of ascorbate peroxidase-monodehydroascorbate reductase-glutathione reductase-glutathione S-transferase enzyme system contributes to failure of anti-oxidative response and persistence of stress environment. Flow cytometric assessment reveals changes in cellular metabolic event along with blockage of cell division at G1 phase and enhances apoptotic cell death. Nuclear internalization along with oxidative burst results in generation of DNA double-strand break which can be the focal point of genome alteration and subsequent gene mutation.

CYTOLOGICAL ASSESSMENT OF SEED PRODUCING CULTIVAR OF CORIANDRUM SATIVUM L. (APIACEAE)

Mitotic and meiotic chromosome studies are performed in Coriandrum sativum L. (Apiaceae) cultivar Co. 3, selection from Acc. No. 695 IARI germplasm, with an objective of cytological indexing for germplasm assessment and genetic exploration. Karyotype details and meiotic (2n=22) chromosome configurations are discussed.

NANOPARTICLES MEDIATED PHENOTYPIC MUTATION IN INDIGOFERA TINCTORIA L. (FAMILY: FABACEAE)

Dry seeds (moisture content: 12.7%) of Indigofera tinctoria L. (family: Fabaceae; dye yielding plant of commerce with immense therapeutic uses) are treated with copper (Cu), cadmium sulphide (CdS), zinc oxide (ZnO) and copper oxide (CuO) nanoparticles (NPs) and also with ethyl methanesulphonate (EMS 0.25, 0.50 and 1.00 %, 4 h duration) and gamma irradiations (50, 100, 150, 200 and 300 Gy) for inducing phenotypic mutation and causing variation in the gene pool which did not exist previously. Out of 11 macromutant types, 6 in EMS, 9 in gamma irradiations, 8 in Cu-NPs and CdS-NPs, 9 in ZnO-NPs and 11 in CuO-NPs are induced. NPs induce relatively higher mutation frequency than EMS and gamma irradiations. Potentiality of NPs inducing genetic variation in the form of macromutation is highlighted. The mutants (2n=16) show normal meiotic chromosome behaviour. Results obtained are discussed.