Aninda Mandal

Cytomixis—a unique phenomenon in animal and plant

Cytomixis is reported to be a uniform phenomenon in the context of fertilization during spermatogenesis of animals and in some lower groups of plants where oogamous reproduction prevails. However, the phenomenon is versatile in flowering taxa as it lacks uniformity in occurrences, causes, formation of intercellular bridges, involvement of number of cells in a cluster, evolutionary significance among others. A review on cytomixis is conducted with an objective that it may offer a scope to unravel some of the ambiguities associated with it and provide further information on cell, reproductive, structural and evolutionary biology.

Nucleotide Sequencing and Identification of Some Wild Mushrooms

The rDNA-ITS (Ribosomal DNA Internal Transcribed Spacers) fragment of the genomic DNA of 8 wild edible mushrooms (collected from Eastern Chota Nagpur Plateau of West Bengal, India) was amplified using ITS1 (Internal Transcribed Spacers 1) and ITS2 primers and subjected to nucleotide sequence determination for identification of mushrooms as mentioned. The sequences were aligned using ClustalW software program. The aligned sequences revealed identity (homology percentage from GenBank data base) of Amanita hemibapha [CN (Chota Nagpur) 1, % identity 99 (JX844716.1)], Amanita sp. [CN 2, % identity 98 (JX844763.1)], Astraeus hygrometricus [CN 3, % identity 87 (FJ536664.1)], Termitomyces sp. [CN 4, % identity 90 (JF746992.1)], Termitomyces sp. [CN 5, % identity 99 (GU001667.1)], T. microcarpus [CN 6, % identity 82 (EF421077.1)], Termitomyces sp. [CN 7, % identity 76 (JF746993.1)], and Volvariella volvacea [CN 8, % identity 100 (JN086680.1)]. Although out of 8 mushrooms 4 could be identified up to species level, the nucleotide sequences of the rest may be relevant to further characterization. A phylogenetic tree is constructed using Neighbor-Joining method showing interrelationship between/among the mushrooms. The determined nucleotide sequences of the mushrooms may provide additional information enriching GenBank database aiding to molecular taxonomy and facilitating its domestication and characterization for human benefits.

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.

Genetic assessment of eight Corchorus spp. (Tiliaceae) using RAPD and ISSR markers

A comparison of the efficiency of RAPD and ISSR primers using different genetic parameters like polymorphism percentage, effective alleles per locus (Aep), genetic diversity per locus (Hep), Shannon diversity index (I), polymorphic information content (PIC) and marker index (MI) has been performed in 8 Indian grown Corchorus spp. (2n = 14) of the family Tiliaceae (C. capsularis L., C. olitorius L., C. aestuans L., C. fascicularis Lamk., C. pseudocapsularis L., C. pseudoolitorius I. and Z., C. tridens L. and C. trilocularis L.). The objective of the work is to develop a simple, efficient and cost effective primer based system for quick genetic evaluation of Corchorus germplasms. Result indicated that OPA 03, OPA 05, OPA 06, OPB 03, OPB 06, OPC 05 and OPC 10 among the employed RAPD markers and (GA)12, (CA)8GC and (GATA)4 among ISSR primers are efficient and effective. Further, relatedness between the species has also been noted using principal component analysis (PCA) and cluster analysis by Unweighted Pair Group Method with Arithmetic Mean (UPGMA) with an objective for efficient breeding and crop improvement. Unrooted phylogenetic tree constructed from molecular data of the studied species revealed possible divaricated mode of origin of Corchorus.

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.

Assessment of methotrexate on dihydrofolate reductase activity, total RNA content and cell division of Lathyrus sativus L.

The effect of methotrexate (MTX), a folate analogue and specific competitive inhibitor of dihydrofolate reductase (DHFR), is assessed (concentrations: 0.001, 0.01, 0.1, 1 and 10 μM) on germinating grass pea (Lathyrus sativus L.) seedlings in relation to radicle length, mitotic index, total RNA content and DHFR activity. Response of callus growth of the species is also studied following MTX treatments. Furthermore, the effect of MTX on seedlings treated with colchicine (0.5%, 8 h) and 5-formyl tetrahydrofolate (CF; 10 mM) are also analyzed. The objective of the present study is to evaluate the effectivity of the drug MTX on a plant species with the view to use plant system as a model for screening antifolate drugs. Results suggest that MTX possesses distinct role in inhibiting plant cell division, RNA synthesis and DHFR activity; although, at low concentration (0.001 μM) it shows stimulatory effect.

Stability Analysis of a High Fibre Yield and Low Lignin Content “Thick Stem” Mutant in Tossa Jute (Corchorus olitorius L.)

A “thick stem” mutant of Corchorus olitorius L. was induced at M2 (0.50%, 4 h, EMS) and the true breeding mutant is assessed across generations (M5 to M7) considering morphometric traits as well as SEM analysis of pollen grains and raw jute fibres, stem anatomy, cytogenetical attributes, and lignin content in relation to control. Furthermore, single fibre diameter and tensile strength are also analysed. The objective is to assess the stability of mutant for its effective exploration for raising a new plant type in tossa jute for commercial exploitation and efficient breeding. The mutant trait is monogenic recessive to normal. Results indicate that “thick stem” mutant is stable across generations (2n = 14) with distinctive high seed and fibre yield and significantly low lignin content. Stem anatomy of the mutant shows significant enhancement in fibre zone, number of fibre pyramids and fibre bundles per pyramid, and diameter of fibre cell in relation to control. Moreover, tensile strength of mutant fibre is significantly higher than control fibre and the trait is inversely related to fibre diameter. However the mutant is associated with low germination frequency, poor seed viability, and high pollen sterility, which may be eliminated through mutational approach followed by rigorous selection and efficient breeding.

Assessment of stability and viability of a jute hybrid (Corchorus capsularis L. × C. trilocularis L.) and its trueness based on RAPD markers

A hybrid line (Corchorus capsularis L. – pollen parent × C. trilocularis L. – stigma parent) of jute (family: Tiliaceae) has been assessed for its stability (using cytomorphological parameters) and viability (using different stain tests including DAPI - 4′,6-diamidino-2-phenylindole) in advance generations (F4 to F6). The trueness of the hybrid is studied following the use of RAPD (random amplification of polymorphic DNA) markers. Results indicate that the hybrid line is stable, viable and true. UPGMA (Unweighted Pair Group Method with Arithmetic Mean) analysis suggests a close relationship as well as distinctiveness between parents and the raised hybrid. Upon considering different genetic efficiency parameters, taken together, it seems that OPA 02, OPA 03, OPB 01, OPB 02, OPB 06, OPC 01 and OPC 06 are effective and efficient RAPD markers for molecular screening of jute germplasms including hybrid(s). OPB 06 is found to be female specific RAPD marker.