Browsing by Author "Selvaraj Gandhimathy"

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IN-VITRO ANTIBACTERIAL ACTIVITY OF ZINC AND COPPER NANOPARTICLES AGAINST GRAM-NEGATIVE BACTERIA AEROMONAS HYDROPHILA
(Malaya Journal of Biosciences, 2014-11-18) Thirunavukkarasu Muralisankar; Periyakali Saravana Bhavan; Selvaraj Gandhimathy; Subramanian Radhakrishnan; Chandirasekar Seenivasan; Palani Aarumugam
The present study was focused to investigate the in-vitro antibacterial activity of bulk and nano forms of zinc (Zn) and copper (Cu) against the Gram-negative pathogenic bacteria Aeromonas hydrophila. The in-vitro antibacterial activities of these metals were determined by well diffusion method. The pure cultures of A. hydrophila were sub cultured on nutrient agar medium and swabbed uniformly onto nutrient agar plates and 6 mm wells were punched into the each nutrient agar plates. Zn, Zn nanoparticles (ZnNPs), Cu and Cu nanoparticles (CuNPs) were suspended in double distilled water using ultra sonicator. Further, the each suspended metals were poured onto each respective wells at the concentrations of 100 µg, 200 µg and 400 µg. The wells without any metal were served as control. The plates were incubated for 24 h at 35-37°C and the antibacterial activity was determined by zone of inhibition in mm. The zone inhibition of A. hydrophyla was observed in all treated wells with both bulk and nanosized metals. Among these metal forms, CuNPs treated well showed more inhibition in all three concentrations followed by Cu, ZnNPs and Zn, whereas, the control wells of the culture plates did not showed any zone inhibition. This study indicates that nano forms of Zn and Cu have more growth inhibition against A. hydrophila. Hence, it suggests that these ZnNPs and CuNPs can be used as antibacterial agent against A. hydrophila.
INSECTICIDAL PROPERTIES OF CAPPARIS DIVARICATA LAM. AGAINST AEDES AEGYPTI LINN. AND SPODOPTERA LITURA FAB
(Department of Botany, Bharathiar University, 2018-08-31) Selvaraj Gandhimathy; Alagarmalai Jeyasankar
The plants hoard vital phytochemicals which have unique properties and functions have been used for human ailments and controlling pest is proven from earlier studies. The exploitation of plant phytochemical compounds for application in pest control can serve a potential alternative against synthetic chemicals. In this perspective the research work was attempted to explore the insecticidal properties of medicinal plant Capparis divaricata against crop insect Spodoptera litura and human vector Aedes aegypti. Plant collection, extraction methods, larvicidal and hemocyte analysis were carried out according to standard protocol with slight modifications. The petroleum ether, chloroform and ethyl acetate extracts have been obtained by soaking method. The larvicidal activity on A. aegypti of IV instar and III instar larvae of S. litura was performed using various concentrations of three extracts. The treated S. litura haemocyte analysis was performed and the morphological changes of treated mosquito larvae and S. litura haemocytes were observed. The data analysis was done using SPSS 16.0. The larvicidal assay on A. aegypti revealed that the ethyl acetate extract and petroleum ether extract showed promising results of above 70% mortality where as chloroform showed mortality above 60%. The larvicidal activities of S. litura using these extracts indicate that the larvae have produced 20% mortality for ethyl acetate extract and less than 5% in other two extracts. However the extract has affected the adult development hence less than 40% of the adult was emerged from pupa which was evident from certain changes observed in the hemocyte morphology of S. litura. This preliminary work on the plant extract has found to be potential in affecting the insect cuticle of A. aegypti larvae and the adult development of S. litura. Detailed study of this plant extract is undertaken against similar insect species.