Browsing by Author "Jayamanne, S. C."

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    Antimicrobial Activity of Seagrss (Cymodocea serrulata) from South West Coast of Sri Lanka
    (Uva Wellassa University of Sri Lanka, 2013) Arulananthan, A.; De Silva, D. P. N.; Jayamanne, S. C.; Dalpatadu, S.L.; Senaratne, S. G.
    Sri Lanka has rich oceanic vegetation along its coastal water bodies. However, utilization of them is limited when compared to terrestrial plants which are used as natural alternatives especially in Ayurveda remedy. It is expected that marine vegetation also ensure the potential bioactivity. Marine plants derived natural products are known as secondary metabolites which are bioactive compounds responsible for antimicrobial activities. Documented results from most of the Atlantic, Pacific, and Indian Ocean resultant macro algae exhibits broad range of biological activities. Some of these are antibacterial, antifungal, antiviral etc. On the other hand, few literature are available on the therapeutic values of seagrasses in Sri Lanka. Therefore, the objective of this study was to test the antimicrobial activity of some selected seagrass species collected from the Beruwela beach rocky platforms and Hikkaduwa coast of Sri Lanka. Methodology Collection and preparation of samples - The fresh seagrass species (Cymodocea serrulata) was collected by hand picking during the low tidal conditions from the submerged rocky platforms of Barberrian reef and in Hikkaduwa coast. The collected vegetation was cleaned well with tap water and distilled water. Then the samples were drained and spread on the filter paper to remove excess water. Samples were chopped into nearly 1cm length pieces prior to grinding using liquid nitrogen. Solvent extraction - Coarsely powdered samples were subjected to solvent extraction by using chloroform, methanol and water solvents. The powdered form of samples and solvents were taken (1:10 w/v) and kept for 24 hours at room temperature (27 °C) in the orbital shaker at 150 rpm. Later, the extracts were filtered through a Buchner funnel with muslin cloth followed by Whatman number 1 filter paper. The resulting filtrates were concentrated by using rotary evaporator. Test microorganism - Human pathogenic Gram positive bacteria Staphylococcus aureus, Gram negative bacteria- Escherichia coli, and a fungal species Candida albicans were used to defeat the antimicrobial activity of C. serrulata. Antimicrobial susceptibility test - Antimicrobial activity of extracts was performed by using the disc diffusion method and agar well diffusion method. The stock solution was prepared with extract of 100 mg/ ml concentration of respective solvents. Sterile discs of 6 mm diameter were prepared in three different quantities (1 mg, 2 mg, and 5 mg). Each plate contained discs with three different quantities and negative control. Agar well diffusion method was carried with all extracts in same concentration as 100 mg/ ml in three different quantities (5 mg, 10 mg and 20 mg). In positive control Kanamycin 10 µl (3µg/ µl) was used for bacterial species and Flucanozole (1.25 µg/ µl) was used as antifungal agent. The plates were incubated overnight.
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    Development of a suitable culture media for mass culture of Moina macrocopa
    (Uva Wellassa University of Sri Lanka, 2015) De Silva, G. N. M.; Jayamanne, S. C.; Chandrarathna, W. P. R.
    Two experiments were conducted to develop a suitable method for culturing Moina macrocopa in National Aquaculture Development Authority (NAQDA) at Rambadagalla. Experiment 1 was conducted to find out possible culture media and to determine its concentration for mass culture. Experiment 2 was conducted to find out the best culture medium and its concentration for mass culture of Moina macrocopa. All bottles and tanks used in experiments were cleaned, drained and sun dried for two days and then filled with water, left for two days before using. Moina macrocopa for all experiments were taken from stock culture developed in NAQDA Centre at Rambadagalla. Pure culture of Chlorella vulgaris (1×10 cells per 1 ml) was acquired from NAQDA Centre at Rambadagalla. Filtered tap water was used in both experiments. In experiment 1, five culture media; mineralized cow dung, steamed cow dung, 15 min. boiled chicken manure, 30 min. boiled chicken manure, and 1 hr. boiled chicken manure were prepared with four different concentrations such as 5 . Different concentrations with various media tested with and without adding Chlorella into the medium. As control, a medium only with Chlorella and water was maintained. Three replicates from each treatment were maintained during experiment. Five individuals of Moina macrocopa were inoculated into each bottle. After that, top of the bottles were covered with a mosquito net to prevent entrance of undesired insects. They were allowed to stay 10 days and after that data were collected. Three samples from every tank were collected using 3 ml of fine dropping pipette. Samples were taken from the surface to bottom at three random points. Collected data (number of Moina macrocopa ) were analyzed using Minitab 16 software with ANOVA, general linear model. According to the results of experiment 1, the positive culture media and their concentrations were used in experiment 2. Selected treatments were prepared as same as in experiment 1. 150 individuals of Moina macrocopa were introduced into each tank. After ten days, 25 ml samples were taken as earlier and preserved using two drops of 1.007 g cm Lugol’s solution. Values of all tanks were recorded. Data were analyzed as in experiment 1. Results and Discussion According to the preliminary experiment, there was a significant relationship between number of Moina macrocopa and culture medium (p<0.05). There was a significant relationship between medium and concentration to the number of Moina macrocopa (p<0.05). There were no results of of mineralized cow dung media. There were no results of Moina macrocopa in 15 g l and 20 g l of steamed cow dung media. Those media may be not favorable for growth of Moina. There were no results found in 15 min. boiled chicken manure and 30 min. boiled chicken manure media. The major reason for boiling chicken manure is to prevent the Salmonella effect. Low time duration for boiling might be not enough for destroy the undesirable pathogens. There may be not a favorable environment for growth of Moina macrocopa in both of those media.