Debadrito Das

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.

B chromosomes in angiosperm—a review

A review article on B chromosomes (Bs) in angiosperms is documented considering occurrence, morphology, polymorphic B forms, divisional phase heterogeneity, chromatin organization and gene content, sequence composition, origin, evolutionary aspects and significant role on host with an objective to foresee the evolutionary perspectives as it still remains an enigma. Irrespective of the origin of Bs, it seems that they have attained the following modifications, namely, insertion of centromeric and telomeric sequences, structural reorganization and procuring mitotic and meiotic drives but shows genetic inertness and present in the host as selfish DNA. In the context, few questions are raised. Further, scientific quest may unravel the unexplored information about Bs to ascertain its evolutionary perspectives, if any.

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.

Polyploidy in Angiosperms: Genetic Insight to the Phenomenon

Polyploidy in angiosperm is a well discussed phenomenon for last few decades but still the proper mechanism and its consequences remain to be an enigma. The present review revisited the phenomenon of polyploidy in angiosperms considering many aspects like genome merging and duplication, restructuring of genome, gene silencing, genome size dynamics, meiotic pairing behaviour of homologues, adaptive significance, relationship between C-value and DNA content among others and a few key questions are raised. It is rather difficult to understand whether all of these regulatory events under the ecological niche are unilateral forces or act as tools of a unified selection machinery of evolution, speciation and diversification. The present discussion may provide genetic insight on the phenomenon in an explicit dimension for proper understanding of evolutionary biology.

RAPD ANALYSIS IN ANDROGRAPHIS PANICULATA (BURM. F.) NESS PLANT TYPES

RAPD (random amplification of polymorphic DNA) markers have been used to eluci date genetic distinctiveness between/among 11 (selfed control lines and 10 true breeding M 4 macro mutant lines) plant types of Andrographis paniculata (Burm. F.) Ness (Family: Acanthaceae; medicinal plant species with immense therapeutic uses) . O ut o f the 30 RAPD primers, 25 reproduced a total of 240 bands of which 170 ( 70.83 %) were polymorphic. The average number of fragments amplified by RAPD markers across the plant types has been 9.6 with a range of 5 to 1 9 (size 190 bp to 1065 bp ) . RAPD primers studie d across the plant types varied in relatio n to scorable fragments , polymorphism percentage ( 28.57 % to 90.91 %), polymorphism information content – PIC (0.07 5 13 to 0. 47230 ) and marker index – MI ( 3.41 to 3 6 . 34 ). R esults obtained for Shannon diversity index - I (2.3 514 to 2.39 85 ), genetic diversity/locus - H ep (0.904 to 0.911) and effective allele/locus – A ep (10.41 to 11.23) suggested narrow genetic base of the studied plant types . Band spectra analyzed by UPGMA (Unweighted Pair Group Method with Arithmetic Mea n) showed 6 major clusters and a close relatedness between/among the plant types, which may be significant for designing efficient breeding programme towards crop improvement . Upon considering different genetic parameters, taken together, it seems that OPA 0 6 , OPA 08 - 09, OPB 0 5 , OP C 0 1 - 04 , OP C 0 6 and OPC 0 9 are efficient and effective RAPD primers for molecular screening of A. paniculata germplasms.

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.

Assessment of Nanotoxicity (Cadmium Sulphide and Copper Oxide) Using Cytogenetical Parameters in Coriandrum sativum L. (Apiaceae)

Present investigation deals with cytogenetical consequences (using attributes namely, seed germination, seedling length, mitotic index, mitotic and meiotic abnormalities and pollen grain sterilities) of cadmium sulphide (CdS) and copper oxide (CuO) nanoparticles (NPs) treatment in Coriandrum sativum L. (Family: Apiaceae, spice of commerce). Ethyl methanesulphonate (EMS), a conventional mutagen is used as positive control. Results suggest that both CdS- and CuO-NPs can induce growth inhibition and cause cytological aberrations in both mitotic and meiotic cells in the studied species. EMS also responds similarly as that of NPs. Study highlights that rooted plant species can be effectively used as model for assessment of nanotoxicity considering cytogenetical parameters.

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.