Siraj Datta

Piper betle leaf extract affects the quorum sensing and hence virulence of Pseudomonas aeruginosa PAO1

Quorum sensing (QS) plays an important role in virulence of Pseudomonas aeruginosa, blocking of QS ability are viewed as viable antimicrobial chemotherapy and which may prove to be a safe anti-virulent drug. Bioactive components from Piper betle have been reported to possess antimicrobial ability. This study envisages on the anti-QS properties of ethanolic extract of P. betle leaf (PbLE) using P. aeruginosa PAO1 as a model organism. A marked reduction in swarming, swimming, and twitching ability of the bacteria is demonstrated in presence of PbLE. The biofilm and pyocyanin production also shows a marked reduction in presence of PbLE, though it does not affect the bacterial growth. Thus, the studies hint on the possible effect of the bioactive components of PbLE on reducing the virulent ability of the bacteria; identification of bioactive compounds should be investigated further.

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.

Study on Folate Binding Domain of Dihydrofolate Reductase in Different Plant species and Human beings.

Data base (NCBI and TIGR) searches are made to retrieve protein sequences of different plant species namely Medicago truncatula, Pisum sativum, Ricinus communis, Arabidopsis thaliana, Vitis vinifera, Glycine max, Daucus carota, Oryza sativa Japonica Group, Arabidopsis lyrata subsp. lyrata, Brachypodium distachyon, Oryza sativa Indica Group, Zea mays and careful alignment of derived sequences shows 95% or higher identity. Similarly, DHFR sequence of human being is also retrieved from NCBI. A phylogenetic tree is constructed from different plant and human DHFR domain using the Neighbour – Joining method in MEGA 5.05. Conservation score is performed by using PARALINE. Result suggests that folate binding domain of dihydrofolare reductase is conserved (score 8.06) and excepting some minor variations the basic structure of the domain in both plant species and human being is rather similar. Human DHFR domain contains PEKN sequence near active site, though proline is common for all the selected organisms but the other sequences are different in plants. The plant domain is always associated with TS (Thymidylate synthase). Plant based system is predicted to be an effective model for assessment of MTX (Methotrexate) and other antifolate drugs.

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.

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.