International Conference on Applied and Pure Sciences (ICAPS)

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Abundance and distribution of microplastics in Muthurajawela wildlife sanctuary and Pamunugama beach, Sri Lanka
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Sandaruwan, U. A. C.; Vithana, P. V. A. S.; Sithumini, W. E. B. K.; Samaraweera, B. G. K. N. D. B.; Tharani, T.; Gallage, C.V.; Subasinghe, K.; Vidanage., S. P.
Microplastics (MPs), defined as plastic particles less than 5 mm, are increasingly recognized as a global environmental threat impacting marine and terrestrial ecosystems. This study investigates the prevalence, distribution and characteristics of MPs in the lagoon and coastal sediments of Muthurajawela Wildlife Sanctuary and Pamunugama Beach in Sri Lanka, areas interconnected through the Negombo Lagoon. Sediment samples were collected from 14 locations (06 from the Muthurajawela lagoon and 08 from the Pamunugama beach) distributed in both in low-tide line and mid-tide line identified through systematic sampling method. From each location, three replicate samples were collected to form a composite sediment sample and 20g of oven-dried sediment was used for analysis of MPs after performing a density separation on the sieved sample. The abundance, size, and shapes of MPs were examined using a stereomicroscope using “Optica TCB5.0” software. Observed MPs were divided into two size ranges: 5 mm – 1.1 mm and 1 mm – 0.5 mm and defined as “large MPs” and “small MPs” respectively. MPs were divided into five categories of shapes: fragments, filaments, films, foams and pellets. Findings indicated a higher abundance of MPs in Pamunugama Beach sediments (79.3 ± 10.3 MPs/Kg) compared to Muthurajawela lagoon (58.0 ± 10.8 MPs/Kg). In Muthurajawela, smaller MPs were more prevalent (79.87%) than larger MPs (20.12%), with a statistically significant difference (p<0.05; Two-sample T test) while Pamunugama Beach showed no significant difference in the abundance of large and small MPs. The abundance of total MPs was not significantly different between low and mid-tide lines at both study sites suggesting a low spatial variability in abundance (p>0.05; Two-sample T test). The most common MP shape in Muthurajawela was filaments (78.8%), while fragments (61.53%) dominated Pamunugama Beach. The study also underscores the impact of the MV X-Press Pearl ship disaster on Pamunugama Beach, contributing to the higher MP levels observed. MPs in Muthurajawela were primarily filament-shaped, likely sourced from urban wastewater and industrial activities, whereas Pamunugama Beach exhibited more fragment-shaped MPs due to recreational activities and natural fragmentation processes driven by coastal dynamics. These findings provide critical baseline data for long-term monitoring and highlight the need for targeted mitigation strategies. Future research should focus on the ecological impacts of MP pollution, particularly on wetland birds and other wildlife in these regions. Comprehensive studies examining the sources, pathways, and ecological consequences of MPs will further inform conservation efforts and policy decisions, ultimately contributing to the protection of Sri Lanka's unique coastal and wetland ecosystems.
Abundance and microplastic characterization found in the mud crab Scylla serrata inhabiting Negombo Lagoon, Sri Lanka
(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Dias, B. C. G.; Amarathunga, A. A. D.; De Silva, D. S. M.; Sivyer, D. B.; Maddumage, M. D. S. R.
Microplastics (MPs) are tiny plastic particles less than 5 mm in size. The danger imposed by MPs continues to rise in the world due to an increase in anthropological pollutants in the environment. The tremendous socioeconomic value and biodiversity of the lagoon have been threatened by a significant accumulation of plastics, particularly MPs. MPs have many negative impacts on the fauna. Herein, the high adsorption capability of MPs increases the toxicity of contaminants as well as oxidative stress that may lead to damaging cell membranes of fauna. Here, we report the investigation on the abundance of MPs in the digestive tract and gills of the mud crab species Scylla serrata, which is a prominent edible food source of humans. We collected fifty two (N = 52) individuals of mud crabs from three crab trapping sites in the Negombo Lagoon, Sri Lanka during November 2022 to March 2023. The gills and digestive tract of the crabs were extracted and digested in KOH, and subsequently the putative MPs were separated and imaged using a stereomicroscope (VWR VisiScope 360) for characterization. In the analysis, a total of 455 MP particles were detected in the crabs, out of which, 187 (41.10%) were in the gills and 268 (58.90%) were in the digestive tracts. The average MP abundance in the gills was 0.70 ± 0.52 items per gram, while that in the digestive tracts was 0.71 ± 0.52 items per gram. The most abundant shapes of MP particles were fibers in the gills (54.01%) and in the digestive tracts (85.07%) followed by fragments and films. Further, the prevailing colours of the MPs were blue, transparent, red, black, and purple. Herein, the digestive tract had the highest concentration of MPs in blue (47.38%), whereas the majority of the MPs found in the gills were transparent (51.8%). The range of MP sizes in the crabs was also determined. The most frequent size range in the gills and digestive tracts were 0.002-0.25 mm (39.5%), and 1.0-5.0 mm (48.8%) respectively. Despite the fact that the current study offered details on the presence of MPs in the gills and digestive tract of the mud crab species Scylla serrata inhabits in the Negombo Lagoon, it also serves as a benchmark for the quick detection of MPs in mud crabs in the lagoons of Sri Lanka.
Activation of wood biochar and red brick using natural coconut vinegar
(Faculty of Science, University of Kelaniya, Sri Lanka, 2020) Malka, U.K.M.; De Silva, R.C.L.; De Silva, D.S.M.; Chandrajith, R.
Number of studies have been carried out to determine the efficiency of strong oxidizers in activating natural raw materials used in low cost water purification processes. However, rural communities find it difficult to acquire most of such chemicals. Therefore, this study was aimed to determine the ability of natural coconut vinegar, which is a common domestic acidic solution, in activating abundantly available potential water purifying materials to reduce calcium (Ca2+) ions from water, further reducing the water hardness. In this study mature barks of Glyricidia (Glyricidia sepium), Gadumba (Trema orientalis) and Ipil Ipil (Leucaena leucocephala) were collected and air dried. These were carbonized (400-450 °C) in a closed vessel (2 hours) to produce biochar. Both biochar and brick particles in the range of 2.0-5.6 mm were selected for the analysis. For the activation these samples were soaked in natural coconut vinegar (biochar/brick: vinegar, 1:2 V/V) for 24 hours and completely dried in an oven (120 °C) for 3 hours. Laboratory scale glass columns (2 cm in diameter) were used to calculate Ca2+ adsorption and retaining capacities. Filtrates were analyzed for Ca2+ using flame photometer. Ca2+ adsorption and retaining capacities of each material were calculated per unit bulk volume of the material. Each test was duplicated, and the average was recorded. Untreated red brick and biochar of Glyricidia, Gadumba, Ipil Ipil showed Ca2+ adsorption capacities of 0.44, 0.30, 0.31, 0.27 mg cm3 and retaining capacities of 0.19, 0.01, 0.02, 0.02 mg cm-3 respectively. Activated red brick and biochar of Glyricidia, Gadumba and Ipil Ipil showed Ca2+ adsorption capacities of 0.76, 0.58, 0.68 and 0.63 mg cm-3 and retaining capacities of 0.25, 0.20, 0.23 and 0.15 mg cm-3 respectively. Increase in Ca2+ adsorption and retaining capacities were observed in all the materials tested after activation with vinegar. Further studies are continued to use the vinegar activated natural materials in a low-cost domestic drinking water purification process.
Acute toxicity of formaldehyde on the ornamental fish, Cyprinus carpio (koi carp) fingerlings
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Rathnayaka, E. M. S. P.; Epa, U. P. K.
The ornamental fish trade is a multibillion-dollar sector that involves more than 125 countries, including Sri Lanka. Formalin, 37% formaldehyde, is widely used in the ornamental fish industry as a prophylactic measure or therapeutic purposes. It is usually used to treat ectoparasites that reside on the body surface or gills of fish, and it is also used as a fungicide for fish eggs. Chemotherapeutic agent usage has been criticized because the indiscriminate usage of chemicals like formalin may cause severe risks to both fish and human health and the environment. The toxicity of chemicals to fish must be decided prior to using any chemical to fish as a therapeutic agent for their diseases. A 96 h acute toxicity test was conducted to determine the median lethal concentration (LC50) of formalin on Cyprinus carpio (Cyprinidae) fingerlings. Experimental fish were exposed to a static bath in 4 L glass aquaria with formalin concentrations of 50, 55, 60, 65 and 70 mg L-1. Seven fingerlings were added to each tank for the acute toxicity test, and glass aquaria were continuously aerated during the test. The control experiment was conducted using de-chlorinated tap water. All five treatments and the control experiment were triplicated. During formalin exposure, fish behavior was observed. The Number of fish deaths was recorded in each concentration separately and probit analysis was conducted to determine the 96-h LC50 value of formalin. Fish behavior changes were investigated during the acute toxicity test. Fish were aggregated near the aeration, erratic swimming with fast movement, fast opercula beating, and fast opening and closing of the mouth, excess mucus production, opercula beating frequency reduction, slow swimming and jumping-like behavior were observed until the beginning of the first death. Mucus accumulation on the body surfaces and gill filament was recorded on dead fish. The gills of the dead fish were damaged and toxicity symptoms were observed. The 70 mg L-1 concentration was the lethal concentration for C. carpio fingerlings in less than 24 h. The LC50 value of formalin on C. carpio fingerlings at 95% confidence level was 55 mg L-1 for 96 h. It was concluded that acute exposure to formaldehyde causes lethal toxic effects on C. carpio fingerlings. Formalin must be used with due care and management in aquaculture practices.
Adsorption of Methylene blue on leaves of Guinea Grass (Panicum maximum)
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Weerathunga, M. A. O. Y.; Dinusha, M. D. N.; Karunathilaka, R. M. M. K.; Priyantha, N.
Massive amounts of industrial pollutants released to the environment because of industrial expansion, which is needed to fulfil the demands of the ever-increasing population, have become a global threat. Consequently, the use of effective treatment methodologies is a necessity, and such methodologies should not only be economical, but also be environmentally friendly. In this respect, biosorption has become a sound alternative for removing toxic industrial dyes. Although many biosorbents have been researched, attempts on their practicability have not been much attended to. This study focuses on the use of Guinea grass (Panicum maximum) leaves, a biosorbent that has not been extensively investigated, for the removal of methylene blue (MB), a common dye used in textiles and other industries. The fibrous nature of this biosorbent would make it suitable for surface modification as needed. Biosorbent for this investigation was prepared by mature leaves of guinea grass, collected randomly from Kandy district, cut into 1.0 – 2.0 cm lengths followed by thorough washing with tap water and deionised water, and then crushing followed by thorough washing again with deionised water until the supernatant became colourless. Samples were then dried at 120 °C for 2.0 h. Parameter optimisation was conducted using 50.0 mL of 10 ppm MB solutions, with one parameter varied at a time while keeping the others unchanged. This process led to optimal values of 0.25 g of adsorbent dosage, 20 minutes of shaking time, 20 minutes of settling time, and a pH of 5.66, based on absorption measurements recorded at 664 nm, achieving an excellent removal rate of 97.5% is obtained. Moreover, this biosorption system reaches equilibrium in a very short time owing to the fibrous nature which is advantageous for extension of bench work toward large-scale removal of MB from contaminated industrial effluents. It is further determined that the transfer of MB from solution to the biosorbent surface follows the pseudo secondorder kinetics model with a high correlation coefficient (R2) of 0.9889.
Adulteration detection of Cinnamomum verum with BarHRM technology
(Faculty of Science, University of Kelaniya, Sri Lanka, 2020) Peiris, M.A.L.M.; Silva, F.H.C.; Wijesinghe, W.R.P.
Sri Lanka is the premier exporter of the true cinnamon (C. verum) in the global market. However, Sri Lankan true cinnamon faces a major threat due to severe competition and adulteration from its substitute cassia (e.g. C. aromaticum). It costs one-third of the price of C. verum but it contains coumarin which is a hepatotoxin at substantial amounts (up to 5%) whereas true cinnamon has only trace amounts (about 0.004%). Therefore, it is paramount to detect adulteration of C. verum from its substitute to protect the reputation of true cinnamon. Chemical and morphological methods can detect the adulteration of C. verum but when it comes to admixtures and value-added products, morphological and chemical methods are not accurate. Hence, the objective of the research was to develop a molecular assay to detect adulteration in commercially available cinnamon products. In this study, DNA sequences of C. verum and C. aromaticum were extracted from the National Center for Biotechnology Information (NCBI) using the keyword “Cinnamomum” and selected barcode region “rbcL”. Gene-specific novel markers were manually designed targeting the identified diagnostic SNP sites. Primer properties were analyzed using NetPrimer software and primers with the best qualities were selected. DNA extraction of cinnamon was done using CTAB method with slight modifications. Real-time PCR and melting curve analysis at 65 ⁰C to 95 ⁰C with a ramping rate of 0.05 ⁰C (Qiagen, Germany) was performed. The melting curve analysis and principal component analysis of the data demonstrated a clear distinction between the two species and results confirm that rbcL gene-specific primers can be used to distinguish C. verum from C. aromaticum. Further, this assay has a great potential to quantify adulterants in commercially available cinnamon samples and extremely valuable for an accurate and rapid adulteration detection of cinnamon value-added products in the global and local market.
The affinity of the major compounds of bitter melon to receptors for insulin in the PI3K-AKT signaling pathway: computational chemistry insight
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Ananda, A. M.; Kadigamuwa, C.C.
The World Health Organization reports diabetes as the fifth leading global cause of death. Bitter melon (Momordica charantia) is an herbaceous plant used for the treatment of diabetes. It includes insulinlike compounds such Charantin, Momordicine II and Cucurbitacine I with anti-diabetic properties. Insulin is widely used to treat type 1 and 2 diabetes, maintaining stable glucose levels in the body. Insulin-like compounds from bitter melon bind to the insulin receptor, regulating glucose absorption and metabolism by activating insulin signaling through the PI3K/AKT pathway. This enhances insulin sensitivity in diabetics by promoting glucose uptake in skeletal muscles via the translocation of glucose transporter type 4 (GLUT4) to the cell surface. AKT (Protein Kinase B) phosphorylates key regulatory proteins like AS160, facilitating the movement of GLUT4 from vesicles, enabling glucose entry into cells for metabolism. AKT also stimulates glycogen synthesis by activating glycogen synthase (GS), converting glucose into glycogen. This combined effect of enhancing glucose uptake and glycogen storage helps lower blood sugar levels effectively. In this research, the aim estimates the binding affinity of major cytochemical in bitter melon by docking analysis. The twenty compounds in bitter melon were selected by literature analysis, and they were downloaded by PubChem in SDF format and translated into PDB through OpenBabel 3.1.1. Then download the 3D structure of insulin receptor protein from the protein data bank (PDB ID: 1IR3). Cleaned the downloaded receptor protein using the Discovery Studio 2021 Client. Molecular docking is performed by Autodock 4.2 and a Lamarckian genetic algorithm. In an in-depth review of 20 compounds that bind to insulin receptor protein (1IR3). Momordicilin has the highest binding affinity (lowest binding energy), and Momordicoside L has the lowest binding affinity (highest binding energy). The ascending order shows the lowest binding affinity to the highest binding affinity, such as Momordicoside L (-2.05 kcal/mol) < Vicine (-3.61 kcal/mol) < Karaviloside XI (-4.15 kcal/mol) < Kuguaglycoside C (-4.38 kcal/mol) < Momordicin II (-4.31 kcal/mol) < Cucurbitacin C (-4.53 kcal/mol) < Momordicoside K (-4.80 kcal/mol) < Momordicoside I (-5.10 kcal/mol) < Cucurbitacin B (-5.19 kcal/mol) < Cucurbitacin E (-5.29 kcal/mol) < Charantin (- 5.25 kcal/mol) < Charantoside C (-5.69 kcal/mol) < Karaviloside III (-5.50 kcal/mol) < Momordicin I (-6.22 kcal/mol) < Cucurbitacin I (-6.28 kcal/mol) < Karavilagenin A (-6.44 kcal/mol < Kuguacin H (- 6.49 kca/mol) < (-) Momordenol (-6.51 kcal/mol) < Kuguacin J (-6.59 kcal/mol) < Momordicilin (-7.12 kcal/mol). Momordicilin interacts with insulin receptor protein’s binding sites, consisting of covalent hydrogen bonds with amino acid residues PRO A1106, PRO A1093, and alkyl and pi alkyl linkages with amino acid residues PRO A1093, PRO A1103. The binding affinity of compounds with binding energy greater than (-7) kcal/mol increases because those compounds bind well with the 1IR3 protein receptor and enhance insulin & also them are suitable for drug development. This computational analysis contributes to the design of new structural molecules, potentially improving the creation of drugs, especially for the production of more effective antidiabetics.
Allelopathic effects of aqueous extract of invasive alien cactus on seed germination and seedling growth of an invasive alien legume – Leucaena leucocephala
(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Sandamini, O. V. P. H. N.; Ratnayake, R. M. C. S
One impact of Alien invasive plants (AIP) on the ecosystems is allelopathy. The allelopathic activity of the aqueous extract of an AIP, Opuntia stricta on seed germination and seedling growth of Leucaena leucocephala (AIP) were studied in this research. Selection of these two AIP based control of AIP by utilization. A concentration series of 10, 25, 50, and 75 g L-1 O. stricta was tested with distilled water as the control to assess seed germination percentages, mean shoot lengths and mean root lengths of L. leucocephala. The viability of the L. leucocephala seed lots were 80%. A pot experiment was conducted to investigate the seedling growth performance of L. leucocephala. All the data were subjected to the One-way ANOVA test at p ≤ 0.05 followed by Tukey pairwise comparison using the “R” software. The highest and lowest germination percentages were recorded in control (60.0 ± 2.9) and 50 g L-1 treatment (43.3 ± 1.6) respectively after four weeks. Seed germination percentages of L. leucocephala were decreased under the different concentrations of O. stricta extract compared to the control. However, the difference was not significant (One-way ANOVA, p ≤ 0.05). The lowest mean shoot (37.6 ± 3.5 cm) and root (11.3 ± 0.3 cm) lengths of L. leucocephala were observed at 50 g L-1 concentration after 12 weeks. There was no significant difference among the shoot length of L. leucocephala plants in all treatments. There was a significant difference in the mean root length of L. leucocephala plants between 10 and 75 g L-1 treatments. The highest mean shoot (49.7 ± 1.9 cm) and root (13.5 ± 0.8 cm) lengths were observed at 75 g L-1 concentration indicating allelochemicals enhanced the seedling growth of L. leucocephala. The 75 g L-1 concentration showed a fertilizer effect by increases in the mean shoot length and mean root length of L. leucocephala. As an AIP, L. leucocephala may also possess allelopathic compounds of its own, which could interact with those of allelochemicals in O. stricta extracts and neutralized the allopathy. Therefore, the growth performance of L. leucocephala was enhanced. The findings of the study provide novel knowledge and understanding of the competitive nature of both AIP studied in relation to their allelopathy.
Allelopathic effects of Prosopis juliflora (Sw.) Dc. on selected crops and native plants
(Faculty of Science, University of Kelaniya, Sri Lanka., 2021) Jayasinghe, J. A. C. P.; Ratnayake, R. M. C. S.
Allelopathic effects of exotic plant species in natural and agricultural ecosystems have received increasing attention because of their negative impacts on native plant growth and reduction of crops yields. It was hypothesized that leaf extracts of P. juliflora have allelochemicals that could inhibit seed germination and seedling growth of the selected plants. The objective of the study was to investigate the allelopathic effects of the Prosopis juliflora leaves on seed germination and seedling growth of selected crops (Eleusine coracana, Vigna radiata) and native plants (Manilkara hexandra, Calophyllum inophyllum). The stock extract (100 gL-1) was preparedfrom P. juliflora leaves collected from Bundala National Park after five days of digestion in deionized water. The stock solution was used to prepare dilution series for applications (10.0 gL-1, 25.0 gL- 1, 50.0 gL-1, and 75.0 gL -1). The above concentrations of P. juliflora leaf extracts were separately tested for percentage seed germination, shoot lengths, root lengths, and seedling growth of the selected plant species with distilled water as the control. Seed germination percentages, root lengths, and shoot lengths results of the test species were analyzed using One-way ANOVA followed by Tukey’s test at p=005. The findings indicate that with the increasing concentration of P. juliflora leaf extracts, seed germination and seedling growth of E. coracana, V. radiata were significantly reduced. The negative effects were more visible in E. coracana than V. radiata. The lowest germination percentage of E. coracana (0.0 %) was observed when seeds were treated with 100 gL-1 and 75 gL-1 and C. inophyllum seeds were also not germinated in those concentrations. Manilkara hexandra seeds were not germinated in all concentrations of P. juliflora leaf extracts. Allelopathy was concentration-dependent and with increasing concentration of P. juliflora leaf extract, seed germination and seedling growth of C. inophyllum significantly reduced (One-way Anova, p=0.05). Hence it showed that Prosopis juliflora aqueous leaf extracts have an allelopathic effects on the seed germination and seedling growth of the selected crops and the native plants. Therefore, allelopathic effects of the aqueous leaf extracts P. juliflora need to consider in forest management and agriculture.
Alleviation of drought stress on immature tea (Camellia sinensis) plants by exogenous application of Abscisic acid (ABA)
(Faculty of Science, University of Kelaniya Sri Lanka, 2022) Damayanthi, M. M. N.; Wijeratne, T. L.; Damunupola, J. W.
Phytohormones are chemical substances regulating various physiological and biochemical processes in plants. Abscisic acid (ABA) plays a major role in response to drought stress. This study was done to identify the role of exogenous ABA application in immature tea during progressive drought. The experiment was conducted in a glasshouse at the Tea Research Institute of Sri Lanka, using one-year-old potted tea cultivars, TRI 2025 (drought tolerant) and TRI 2023 (drought susceptible). Plants were brought to field capacity and exposed to a drying cycle by withholding water. When plants achieved moderate moisture stress (volumetric water content around 25% in soil), plants were foliar sprayed with ABA at various concentrations [0 (water-spray – WS), 50, 100, 150 and 200 ppm] along with well-watered (WW - positive control) and no-spray (NS - negative control) treatments. Data were collected at 18 hours and 3, 7, 14 and 21 Days After Spraying (DAS) from randomly selected plants arranged according to Randomized Complete Block Design with 2 blocks and 24 replicate plants per cultivar per treatment. At 21 DAS, plants were re-watered, and the recovery was visually assessed after another 7 days. Physiological and biochemical parameters were measured (9.00 am to 12.30 pm) along with soil moisture content. Maintenance of comparatively a higher relative water content was observed in tea plants treated with 100, 150 and 200 ppm ABA. Although the reduction of gas exchange parameters was initially higher in ABA treated plants, it was significantly lower at later stages with progressive drought. Application of ABA in concentrations of 100 - 200 ppm resulted in comparatively higher photosynthetic rates and stomatal conductance at latter stages (14 DAS and 21 DAS). It was observed that the application of ABA did not improve osmolytes accumulation in tea under drought. At latter stage, 100 - 200 ppm ABA treated plants exhibited comparatively higher total chlorophyll and polyphenolic content in both cultivars compared to NS and WS treatments. Similarly, ABA treatments significantly increased antioxidant activity over NS and WS treatments towards the latter stage of drought. The maintenance of significantly lower dark respiration and higher recovery percentages were also observed in ABA (100 - 200 ppm) sprayed plants. Therefore, it can be concluded that ABA foliar application improves water retention and gas exchange parameters while preserving antioxidant capacity resulting restricted risk of oxidative damage under drought. The exogenous ABA application ameliorates the adverse effects of drought stress and improves drought tolerance in immature tea plants. The levels of 100 - 200 ppm concentration of ABA was better in terms of physiological and biochemical alteration and recovery under drought stress in both tea cultivars. Accordingly, considering the cost factor, the application of 100 ppm ABA can be recommended to use as a potential tool to minimize the drought stress effects in immature tea plants.
Aloe vera gel and cinnamon essential oils-incorporated Aloe vera on stem-end rot control of mango (cv. Karthakolomban) using dip treatment
(Faculty of Science, University of Kelaniya, Sri Lanka, 2020) Karunarathna, N.S.N.; Abeywickrama, K.
Stem-end rot (SER) is a major post-harvest disease of mango worldwide. Naturally occurring biologically active compounds from plants are expected to be more suitable and less harmful than synthetic fungicides. Current research was carried out to investigate the applicability of Aloe vera gel and cinnamon bark oil and cinnamon leaf oil-incorporated Aloe vera gel in controlling SER and extending post-harvest shelf life of mango (cv. Karthakolomban). Dip treatments of A. vera gel and cinnamon bark oil (2.0 μL/mL) and cinnamon leaf oil (2.0 μL/mL) incorporated A. vera gel were carried out for 90-day old mango fruits and their pathological, physicochemical, sensory properties and percentage shriveling were evaluated after 10-day storage at 12-14 ℃. After the initial dip treatment trial, a scaling up experiment was conducted using the best treatments where treated and control mangoes were placed in ventilated corrugated fiberboard boxes instead of plastic trays to store mango at 12-14 ℃. Statistical analysis of the results was carried out using MINITAB 18 statistical software. Data with respect to physicochemical properties were analyzed using One-way ANOVA and Tukey’s multiple comparison test. Kruskal Wallis non-parametric test was used to analyze data with respect to pathological, shriveling and sensory properties. Dip treatments of Aloe vera gel in combination with cinnamon leaf and bark oils reduced SER severity of mango to 3.0% in both trials once fruits were subjected to induce ripening. A. vera gel treatment reduced SER severity of mango to 6.0%. A. vera gel, cinnamon bark and leaf oil-incorporated A. vera gel treatments significantly reduced SER severity of mango in comparison to the negative control (distilled water) which showed SER severity of 19.0%. Physicochemical properties namely total soluble solids, titratable acidity, pH, firmness and weight loss of A. vera gel and gel plus oil treated mangoes were similar to the negative control fruits according to the statistical analysis. Percentage shriveling of mango subjected to A. vera gel treatments was reduced to 0- 0.4% compared to the uncoated control fruits which indicated a shriveling of 1.6%. Sensory properties of mango did not demonstrate any drastic alteration between all treatments. Current ecofriendly treatment strategies could be introduced to horticulture industry to reduce post-harvest loss of mango in local trade, during transportation and exportation via air cargo within 10 days.
Alpha-amylase and alpha-glucosidase inhibitory activities of a novel compound isolated from Murraya koenigii
(Faculty of Science, University of Kelaniya Sri Lanka, 2022) Sampath, S. N. T. I.; Jayasinghe, J. M. S.; Attanayake, A. P.; Karunaratne, V.
Herbal plants are composed of a vast amount of novel antidiabetic drugs for the management of diabetes mellitus. The leaves of Murraya koenigii L. Sprengel. which belongs to Family- Rutaceae (Common name- curry leaves) plant is known to be a promising source of natural bioactive compounds. In this research, we report the isolation and characterization of a new compound from hexane extract of leaves of M. koenigii and its in vitro antidiabetic activity. The new compound was identified as 3,3',5,5',8-pentamethyl-3,3'-bis (4-methylpent-3-en-1-yl)-3,3',11,11'-tetrahydro-10,10'-bipyrano [3,2-a] carbazole and the structure was elucidated based on extensive 13C and 1H NMR, high-resolution mass spectrometry (HRMS) and 2D NMR analysis. Investigated the in vitro antidiabetic activity of the new dimer using alpha-amylase and alpha-glucosidase enzyme inhibition activities. The compound exhibited significant alpha-amylase activity (IC50 = 30.32 ±0.34 ppm) and the alpha-glucosidase inhibition activity (IC50 = 30.91 ±0.36 ppm) when compared with the acarbose at 0.05 significant level. These results revealed that the new compound isolated from the hexane extract of leaves of M. koenigii could act as an antidiabetic agent.
Alternative gelling agents to develop cost effective medium for in vitro propagation of Dendrobium cv. “Big Jumbo White”
(Faculty of Science, University of Kelaniya Sri Lanka, 2022) Kanishka, W. S.; Lakmali, G. B. T.; Umesha, M. S. P.; Priyadarshan, A. I. S.; Senanayake, S. P.
In vitro propagation is the most common method of Dendrobium propagation. Commonly, agar is used as an effective gelling agent though, it is expensive. However, the developing a cost-effective method is beneficial for small-batch productions and is recommended. The objective of the current study was to evaluate the efficacy of ‘kithul’ flour (starch extracted from the pith of Caryota urens) and xanthan gum as alternative gelling agents to develop an efficient, cost-effective medium for in vitro propagation of Dendrobium. Seeds of Dendrobium cv. “Big Jumbo White” was cultured using full-strength Murashige and Skoog (MS) medium. After 90 days of incubation, 1g of Protocorm Like Bodies (PLBs) and plantlets of Dendrobium cv. “Big Jumbo White” were transferred to twelve different MS media supplemented with BAP (Benzyl Amino Purine) (2.5 mg/L) and NAA (Naphthalene Acetic Acid) (0.5 mg/L) and solidified with either agar (1:0) or with alternative agents; kithul flour (0:1) and xanthan gum (0:1) or a series of combinations of each alternative gelling agent with agar (1:4, 2:3, 3:2 and 4:1) totalling to 12 treatments with six number of replicates per each. The weight of plantlets and PLBs, number of plantlets, number of leaves, number of roots, and length of the roots were recorded as growth parameters in fortnight intervals for a period of 90 days to assess the growth performance. After 90 days of incubation, the MS medium of agar: kithul flour (1:4) of the treatment series with kithul flour and agar: xanthan gum (2:3) of the treatment series of xanthan gum, have shown significantly high performance in the growth and development of PLBs and plantlets. Four growth parameters, number of plantlets: 44, number of leaves per plantlet: 5, number of roots per plantlet: 12 and root length: 1.5 cm, were significantly high in the agar: kithul flour (1:4) medium than in the agar: xanthan gum (2:3) medium. Moreover, compared to the conventional tissue culture media prepared using only agar, the modified medium using agar: kithul flour (1:4) has shown 73% of cost reduction. In conclusion, the use of agar and kithul flour (1:4) as an alternative gelling agent can be recommended as a cost-effective medium for the development of PLBs into plantlets of Dendrobium cv. “Big Jumbo White” on a small scale in vitro culture system.
Analyse and design for water distribution network in community water supply using different simulation techniques
(Faculty of Science, University of Kelaniya Sri Lanka, 2022) Sutharsan, M. E.
The water supply scheme mainly supplies potable water to houses, commercial and industrial institutions. Supplying water to the consumers at the required quantity with adequate pressure is the prime purpose of any water distribution network (WDN). However, the performance of the WDN may vary from the original design in the long run. In this study, a WDN network model was built using WaterGEMS and WaterCAD computer simulators and hydraulic analyses were conducted to obtain an optimal WDN design for an existing community water supply scheme of a village called Poomalanthan in Sri Lanka. A series of steps such as; models, network representation, verification, problem identification, model application, and results analysis were carried out in developing the WDN simulation model. The demand for domestic, industrial, commercial and unaccounted for water was forecasted for twenty-five years while considering the average per capita daily demand as 100 litres. The analysis was carried out using the Hazen-Williams friction method and the hydraulic parameters such as pressure, flow velocity and flow rate were analysed under extended period simulation. The result revealed that all nodes in WDN operate above the threshold pressure limit of 10 mH2O pressure throughout the day, including peak hours. The pressure during peak hours is the critical output factor which shall give an idea of ensuring water supply to every consumer at an adequate pressure. The nodal pressure is negatively correlated with the ground elevation. Most pipes have a relatively low velocity than specified in the design guidelines, which may be due to the low daily water demand of the small community. However, the chance of silt deposition in the pipes is the disadvantage of maintaining low velocity in WDN. Hence frequent pipeline line washout is recommended to eliminate the silt deposition in the system. The water flow rate in the pipes depends on the water demand at every node. The same hourly flow rate was not observed since the demand in the system was not constant throughout the day. Instead, it varies with the time of the day, and usually, the peak demand arises in the morning and late evening hours when people consume water for bathing, washing, and cooking. The water tower was optimised at 10m height to supply water at sufficient pressure. The WDN was designed for optimised pipe sizes with pipe availability in the market. Statistical comparison through an ANOVA test reveals that there is no significant difference in the nodal pressure, flow velocity and flow rate results derived from WaterGEMS and WaterCAD simulation techniques. Water network computer simulators used during this design can handle various water supply network problems. Computer-aided WDN simulation techniques provide significant advantages over conservational computations in terms of optimisation, results in accuracy, monitoring of the system during operation, time consumption and room for future modification.
Analyses of biometric growth parameters and feeding habits of Mugil cephalus (Flathead mullet): One of the economically important fish species collected from Negombo Lagoon
(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Nimasha, N. T. P.; Perera, H. A. C. C.
Flathead mullet (Mugil cephalus) is found to be a potential candidate species in brackish water aquaculture due to its euryhaline nature, and it has ready markets for seeds as well as processed products. However, the lack of data on adult flathead mullets in the natural environment in Sri Lankan waters is the major constraint to study the biology of the species and management practices for fish resources. The present study was conducted to analyze the diet composition, length-weight relationship, and condition factor of M. cephalus belonging to the family Mugilidae collected from the Negombo lagoon, Sri Lanka. In fisheries science, the important condition factors are the growth, health state and feeding intensity. The sampling was done from August 2022 to March 2023. A total of 100 specimens were collected from the catches of artisanal fisheries from Negombo lagoon area. The total length and weight of fish were measured and varied in a range of 16.9 cm - 32.0 cm and 55.50 g - 291.70 g respectively. Length frequency distribution showed that the total length class 23 cm - 24 cm had the highest frequency of 100 samples. The FishBase reports length at first maturity as 30.0 cm and the percentage below 30 cm was observed as 97%. Results obtained showed a negative allometric growth pattern for this fish species (b<3, t-test, p< 0.05) with a significant linear relationship given by the equation; W = 0.0266TL2.690 (Log W = - 1.575 + 2.690 log TL (R2 = 0.951, n=100). Fulton’s condition factor (K) of males and females of M. cephalus was 1.0501 + 0.0359, and 1.0048 + 0.0123 respectively. Mean Fulton’s condition factor for immature mullets was lower than (0.9960 + 0.0724) that of the mature ones (1.0373 + 0.0735). Relative Gut Length (RGL) and Gastro Somatic Index (Ga.SI) were 1.52 – 3.18 and 2.012 – 3.874 respectively. The recorded mean RGL (2.442 + 0.146), confirmed that M. cephalus is omnivore species. The stomach content was analyzed using the frequency of occurrence method showed that algae (30.86%), sand particles (25.71%), and detritus (23.43%) as main food items. The food of animal origin consisted of annelids, insect parts and crustaceans. Most of the fish were one-fourth filled (1/4) at the time of capture. The immature individuals recorded from the Negombo lagoon area were 49 %. The present study reported the presence of synthetic debris such as nylon threads in the stomachs of flathead mullets revealing that the area is polluted. Therefore, more research into the effect of synthetic debris on the lagoon area is recommended. Continuous monitoring of fish landings is also recommended as immature individuals recorded were significant in the fish catch.
Analyses of biometric growth parameters, feeding ecology and fisheries aspects of Frigate Tuna (Auxis thazard), a Neritic Tuna species found off the east, west and south coasts of Sri Lanka
(Faculty of Science, University of Kelaniya Sri Lanka, 2022) Rathnayaka, A. P. H. B.; Perera, H. A. C. C.; Perera, U. L. K.
Frigate tuna (Auxis thazard) is a commercially important neritic tuna species in Sri Lanka contributing to over 40% of the total neritic tuna catch of the country. Only a few studies have been conducted on biometric parameters of frigate tuna in Sri Lankan waters. Therefore, the present study was conducted to study the growth condition indices and fisheries aspects of A. thazard in selected coastal waters around Sri Lanka and the feeding ecology of A. thazard in the West coast of the country. The study was based on a primary data analysis where the data were collected from the West coast from November 2021 to February 2022 and a secondary data analysis in which the data were obtained from the Department of Fisheries and Aquatic Resources (DFAR) following the year 2017 for a comparative study off the Western, Southern and Eastern coasts of Sri Lanka. The Length–weight relationship (LWR) and Fulton’s condition factor (K) were estimated using the equations 𝑊 = 𝑎𝐿𝑏 and 𝐾=100𝑊/𝐿3 to assess the condition of the fish. The total weight ranged from 124.90 g -1405.05 g, 157.00 g -1475.00 g and 152.60 g - 890.40 g and further total lengths ranged from 23.8 cm - 44.2 cm, 21.5 cm - 46.5 cm and 25.5 cm - 44.1 cm for Western, Southern and Eastern coasts respectively. The LWRs were 𝑊= 0.0012𝑇𝐿3.6586, 𝑊 = 0.0026𝑇𝐿3.4846 and 𝑊 = 0.0147𝑇𝐿2.951, in which the pooled ‘b’ values 3.6586 and 3.4846 for the West and South coasts indicating positive allometric growth (b>3, t-test, p<0.05) and 2.951 for the East coast indicating isometric growth (b=3, t-test, p>0.05). Both male and female fish on each coast followed the same growth pattern without any difference. The K values 1.21 ± 0.42 and 1.43 ± 0.98 calculated for the West and South coasts indicated relatively healthy conditions and 0.94 ± 0.51 on the East coast indicated comparatively poor conditions. The gillnets accounted for 98% of catches on the West coast and ring nets accounted for 68% and 67% for South and East catches based on the total landings in 2017. In the primary data analysis, the estimated Relative Gut Length (RGL) confirmed the frigate tuna as a carnivore. The size classes of 30.0 - 31.50 cm and 23.50 - 24.50 cm had the highest and lowest feeding intensities based on the Gastro Somatic Index (GaSI). The most preferred prey item was shrimps. The Fishbase reports length at first maturity as 29.5 cm. The percentages below 29.5 cm include 18.83%, 39.18% and 33.99% for the West, South and East coasts, respectively. Therefore, continuous monitoring of fish landings and data collection is recommended for a sustainable fishery.
Analyses of biometric parameters, feeding, and fisheries aspects of Spotted Sardinella (Amblygaster sirm) occurring along the Negombo coastal waters of Sri Lanka
(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Wijesooriya, W. M. N. S.; Ratnayake, R. P. P.; Perera, H. A. C. C.
Amblygaster sirm is one of the major food fish in the small pelagic fishery in Sri Lanka. The study analyzed biometric parameters, feeding habits, and fisheries aspects of A. sirm in Negombo coastal waters. Two hundred A. sirm individuals were collected from the Negombo fish landing center and monthly interval from August 2022 to March 2023. The weight and total length of the collected fish ranged from 17.50 g - 109.00 g and 12.80 cm - 22.60 cm respectively. The lengthweight relationship (W=aLb) of males, females and pooled was W= 0.0029 TL 3.3546, W= 0.0035 TL 3.2819 and W= 0.0030 TL 3.3459. The significant deviation of the 'b' values from 3.0 indicates an allometric growth pattern for A. sirm in the coastal waters of Negombo (one-sample t-testp< 0.05). The Fulton’s condition factor (K) using the formula K = 100*W/TL, 0.9047 ± 0.1074, 0.94392 ± 0.08699 and 0.92331 ± 0.09995, for males, females and pooled respectively. The stomach-fullness of fish examined: were 40% empty, 15% one-fourth full, 12.5% half full, 27.5% three-fourth full, and 5% full stomach. Food and feeding analyses showed that ingested food includes 14.29% of phytoplankton including 1.53% of algae, 23.98% of mollusc larvae, 25.51% of crustacean larvae, 15.31% of fish eggs, 12.76% of arthropod appendages, 2.55% of synthetic fibers and 4.08% of unknown particles. According to the average Gastro Somatic Index, the highest and lowest feeding intensities using stomach fullness index were observed in the size class of 17.5 cm - 18.5 cm and 12.5 cm - 13.5 cm respectively. Their most preferred prey was crustacean larvae. The major vessel type used in fishing was Fiberglass Reinforced Plastic (OFRP) boats, operated within 15 - 20 fathom in depth. The small mesh drift gillnets with 31.75 mm and 38.1 mm mesh sizes was popular among the community. Of that, 38.1 mm mesh sizes are widely used. Synthetic materials in stomach content provide compelling evidence of the widespread contamination of marine ecosystems by human-made materials. The ingestion of these synthetic materials by fish poses a threat not only to their health but also to the overall ecological balance of marine habitats. Therefore, long term monitoring and research is recommended for the sustainable utilization of spotted sardinella fishery resources in Sri Lankan coastal waters.
Analysis of biogenic amines in grave soil and cadaver dog training aids using gas chromatography mass spectrometry
(Faculty of Science, University of Kelaniya, Sri Lanka, 2021) Perera, U. D. N. T.; Wisor, M. R.
In a forensic investigation of a missing persons or a suspected murder, finding human remains plays a vital role. Currently, the most common method to find these remains is the use of human remains detection dogs or HRD dogs. Although, these dogs can distinguish human remains from animal remains, and find human remains buried in significant depths, the scientific basis for this remarkable ability is not well understood. HRD dog’s ability to detect human remains depends on the volatile organic compounds (VOCs) produced during the decomposition process. These VOCs contribute to the “smell of death” and the analysis of them is crucial to understand the differences between human and animal decomposition odor. Additionally, some HRD dogs are trained using cadaver dog training aids known as “pseudo corpse” due to the limited availability of decomposing human remains for training purposes. In some studies, these training aids are found to be less effective compared to real human remains. Although biogenic amines like putrescine and cadaverine are present in grave soil and decomposition odor, the presence of these compounds in decomposition odor is not well reported in literature. In previous work researchers have used gas chromatography mass spectrometry (GC-MS) in decomposition odor analysis. These amines often have high basicity, high polarity, and low volatility compared to other VOCs, and they tend to absorb and decompose in the GC column, sample vessels, and injection system making them hard to detect in low concentrations and difficult to analyze using GC-MS. To obviate these problems, the current work focuses on analyzing these amines by derivatizing them followed by the analysis using GCMS. Furthermore, an extraction method is developed to extract amines from soil samples. Three derivatization agents trifluoroacytalacetone (FAA), pentafluoroproponic anhydride (PFPA) and, isobutyl chloroformate (IBCF) were investigated and IBCF showed promising results. This method was used to analyze grave soil samples collected near to a partially decomposed human body and a relatively fresh human body and three commercially available cadaver dog training aids. Cadaverine and putrescine were present in one of the cadaver dog training aids at concentrations of 780. ± 6 mg/mL and 1440. ± 6 mg/mL respectively. Only cadaverine was present in the second training aid at a concentration of 426 ± 6 mg/mL. One training aid did not contain any amines in detectable levels. Soil obtained near the partially decomposed corpse showed a slightly elevated amount of cadaverine at a concentration of 37 ± 1 mg/g compared to the body that was recently placed which contained 31 ± 1 mg/g of cadaverine. Future work of this research involves the analysis of amines in grave soil during different stages of decomposition.
Analysis of groundwater used in areas beyond the National Water Board distribution network in Ratnapura
(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Karunasena K, . K. A. D. A.; de Silva, D. S. M.; Hakmanage, N. M.
Groundwater is the main source of drinking water in selected areas in Ratnapura where municipal water is not accessible. In a majority of households, it is consumed without any treatment. Waterborne diseases such as dysentery and typhoid fever may spread as a result of microbial pathogens. Chemical contaminants may also result in kidney-related issues. The present study was conducted to evaluate the quality of groundwater in three Grama Niladhari divisions around Ratnapura urban area. Amuwala, Kahengama South and Gonakumbura divisions were selected, and twenty wells were sampled from each division for three months as replicates. Measured parameters included total Coliforms, Escherichia coli, color, turbidity, pH, electrical conductivity, chloride, total alkalinity, total hardness, total iron, sulfate and total dissolved solids (TDS). Onesample t-test was performed at a 5% level of significance to assess the deviation of each parameter from Sri Lanka water quality standards. The results revealed that all water sources in the study were microbiologically contaminated throughout the sampling period. All of the physical and chemical water quality parameters were within the limits of Sri Lanka Standards (SLS) 614: 2013 except the pH level which was below the SLS requirement. The turbidity level was statistically significant at the SLS median value in Kahengama and Gonakumbura. Since the presence of E. coli bacteria indicates potential fecal contamination in the water, public awareness programmes are needed to educate consumers on the importance of consuming boiled water. The low pH issue can also be resolved by using pH adjusting water filters. The municipal distribution lines have to be extended further permitting access to disinfected potable water to a greater number of consumers.
Analysis of phytochemicals and antioxidant properties of Dendrophthoe falcata and Mangifera indica plant leaf extracts
(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Karunarathna, M.G.T.N.; Kadigamuwa, C.C.
Dendrophthoe falcata, a common mistletoe plant, used in traditional medicine has not been adequately studied for the identification of compounds with biological activities. Phytochemical screenings allow the identification of chemical constituents with potential medicinal properties. These bioactive compounds hold promise as starting material for development of drugs. In Sri Lanka Dendrophthoe falcata is abundantly seen in Mangifera indica. The aim of the study is to quantify selected phytochemicals and the antioxidant properties in Dendrophthoe falcata and Mangifera indica (host tree) leaf extracts. The best extraction solvent was determined by cold extraction among methanol, ethanol, acetone, dichloromethane and water. Tannins content was determined using colorimetry with gallic acid as the standard. Alkaloids content was determined by a gravimetric method using acetic acid and ammonium hydroxide. In vitro DPPH (1, 1- diphenyl- 2- picryl-hydrazyl) radical scavenging activity, total phenolic content (TPC), total flavonoid content (TFC) and ferric reducing power assay (FRAP) were used to evaluate the antioxidant activity of plant leaf extracts. The TPC and TFC were determined by using FolinCiocâlteu colorimetric and aluminum chloride methods, respectively. The FRAP value was determined using colorimetry with ascorbic acid as the standard. Methanol had the highest extraction yield (25.20±4.34% w/w) compared to other solvents. Highest alkaloid content was observed in Dendrophthoe falcata leaf extract (DFLE) (31.32±2.59 % w/w). Highest tannin content (51.64±1.72 µg GAE/mL) was observed in Mangifera indica leaf extract (MILE). It was found that the DFLE demonstrated potent antioxidant activity compared to the half maximal inhibitory concentration of MILE calculated using DPPH assay (IC50 of DFLE 760.60±145.02µg/mL). DFLE had the highest TPC value (527.82±9.05 µg GAE/mL) and highest TFC value (399.70±13.95 µg CAE/mL). The maximum ferric reducing power was shown by DFLE (111.51±0.76 µg AAE/mL). The results suggested that the medicinal potential of DFLE is higher than MILE. Classes of compounds identified in Dendrophthoe falcata should be further studied to identify potentially beneficial compounds