Science
Permanent URI for this communityhttp://repository.kln.ac.lk/handle/123456789/1
Browse
8 results
Search Results
Item Species identification and pollination biology of an economically important true halophyte, Salicornia brachiata Roxb.(Aquatic Botany, 2024) Siridewa, K.; De Silva, W.; Ratnayake, R.; Wijesundara, S.; Perera, D.; Attanayake, R. N.Members of the genus Salicornia have gained a global attraction due to their ability to thrive under high saline conditions and as potential candidates in saline agriculture. However, it has been a taxonomically challenging genus for decades since the members show plastic responses to extreme environmental conditions and due to incongruences between morphological and molecular identification methods. While only a handful of commercially grown Salicornia species are fully described, most of the species including S. brachiata, a native species in the Indian sub-continent, Myanmar, and Sri Lanka are poorly described. With the potentials in adapting S. brachiata in saline agriculture, the aim of this study was to establish a morphology and DNA barcodebased species delineation system and to study pollination biology for future crop improvement projects. Tentatively identified S. brachiata plant samples were collected from two populations in Sri Lanka and completely described. GenBank lacked authenticated barcode data for S. brachiata except for one chloroplast genome to which the matK sequence obtained in the present study matched with 100 % identity. For the first time, well defined sequences of three barcode regions, ITS, ETS and matK, of S. brachiata were made available for accurate species identification. Reproductive dynamics in different parts of the inflorescence was studied. A facultative xenogamous mating system was recorded for the first time in the genus and while the lower florets in the cladode showed a preference towards outcrossing, the upper florets displayed adaptations for selfing. Data could be effectively utilized in future Salicornia breeding programs.Item Bioassay-guided isolation and antioxidant properties of phytochemicals present in methanolic extract of Halosarcia indica from salt marsh ecosystems in Sri Lanka(Faculty of Science, University of Kelaniya Sri Lanka, 2024) Siriwardhana, U. L. I. G.; Perera, D.; Attanayake, R. N.; Paranagama, P. A.Halosarcia indica, belonging to the family Amaranthaceae, is a halophyte that exhibits unique adaptations to saline environments. Halophytes contain various bioactive chemicals, including plant polyphenols, which have garnered interest due to their antioxidant properties. Isolation of pure compounds responsible for the antioxidant activity is also very important in nutraceuticals, cosmetics, and pharmaceutical industries. The aim of the present study was to isolate and identify bioactive compounds from H. indica samples collected from Sri Lanka. Fresh plant materials were collected from salt marshes in Mannar district, Sri Lanka. Phytochemicals from finely powdered freeze-dried areal parts of H. indica were extracted using cold extraction and sequentially partitioned with methanol, dichloromethane (DCM), and hexane. The antioxidant activity of these fractions was evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, the 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay, and the Ferric Reducing Antioxidant Power (FRAP) assay, with butylated hydroxytoluene (BHT) serving as the positive control. The total phenolic content (TPC) was assessed using the Folin-Ciocalteu method, while the determination of total flavonoid content (TFC) was conducted through the aluminum chloride assay. Additionally, the total tannin content (TTC) was examined using the vanillin/HCl method. Finally, methanolic and DCM extractions were subjected to column chromatography, thin layer chromatography, and preparative thin layer chromatography techniques to isolate compounds responsible for antioxidant activity. The methanolic fraction exhibited the highest radical scavenging activity, with IC50 values of 69.78 ± 3.48 µg mL-1 in the DPPH assay and 81.38 ± 1.89 µg mL-1 in the ABTS assay, while the positive control BHT showed IC50 values of 20.91 ± 0.48 µg mL-1 and 22.93 ± 0.65 µg mL-1, respectively. In the FRAP assay, the methanolic fraction presented higher mean absorbance values of 0.598 ± 1.81 compared to that of the BHT 0.821 ± 1.82. Methanolic extracts of the H. indica had higher TPC (184.77 ± 3.21 mg GAE/g), TFC (190.69 ± 5.84 mg CE/g), and TTC (201.33 ± 4.21 mg GAE/g) values compared with DCM and hexane extracts. Methanolic extracts showed higher antioxidant activity followed by DCM and hexane extracts. Therefore, two pure compounds with antioxidant activities were isolated in methanolic (IC50 - 78.69 ± 1.24 µg mL-1) and DCM extracts (IC50 - 192.84 ± 1.65 µg mL-1) respectively. The study identified two antioxidant compounds from H. indica extracts, with methanolic extracts showing the highest activity. Further analysis will be done using spectroscopic methods. These two compounds will be identified using spectroscopic techniques, including 1H NMR, 13C NMR, HPLC, and mass spectrometry.Item Evaluation of phytochemical profile and in -vitro antioxidant activity Suaeda maritima(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Pathirana, K. P. S. S.; Herath, H. M. N. P.; Perera, D.; Attanayake, R. N.; Paranagama, P. A.Suaeda maritima, a halophytic plant species from the family Amaranthaceae, possesses unique adaptations that enable it to thrive in high-salt environments. Halophytes contain various bioactive chemicals, including plant polyphenols, which have garnered interest due to their antioxidant properties. This study aims to investigate how the polyphenolic content and antioxidant activity of extracts change across the polar, mid-polar, and non-polar fractions of crude extracts from S. maritima. These extracts are obtained from both the aerial parts and the roots of the plant, which were harvested from Seguwantivu area of Puttalam, Sri Lanka. Each dried and powdered plant part was sequentially extracted into hexane, dichloromethane (DCM), and methanol at ambient temperature using cold maceration. The Antioxidant activity of each concentrated extract was determined by 2,2-diphenyl-1-1-picrylhydrazyl(DPPH) assay, and 2,2'-azino-bis(3- ethylbenzothiazoline-6-sulfonic acid (ABTS) assay , phenolic content by (TPC) by FolinCiocalteau method, flavonoid content (TFC) by aluminum chloride assay and condense tannin content (CTC) by vanillin/HCl method. Six sequential extracts of S. maritima (from aerial parts and roots) showed antioxidant activity. The results indicated that S. maritima shoot extracts have significant levels of polyphenolic compounds (p=0.05), with methanolic extracts exhibiting the highest TPC (31.55±1.54 mg GAE/g dw), TFC (18.41±0.91 mg CE/g dw) and CTC (3.66±0.19 mg CE/g dw). In contrast, root extracts showed lower polyphenolic content (23.69±5.63 mg CE/g dw, methanol extract) but still possessed appreciable antioxidant activity (IC50, 0.40±0.07×10-1 mg/mL DPPH and IC50, 0.69±0.02×10-1 mg/mL ABTS). The ABTS assays revealed the radical scavenging ability of the extracts, with the methanolic aerial parts extract exhibiting the most potent antioxidant activity (IC50, 0.17±0.01×10-1 mg/mL) exhibiting it has more water-soluble antioxidants. Overall, Solvent extracts of the S. maritima possess antioxidant properties at varying levels. The fraction of polar compounds in the areal parts of S. maritima contains a relatively high amount of phenolic compounds and potent antioxidant properties. Moreover, identifying antioxidant properties from halophytes could contribute significantly to developing of natural antioxidants for combating oxidative stress-related diseases.Item Unlocking the potential of convolutional neural networks for precise classification of finger pulse waves in diabetic patients and healthy individuals(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Gunathilaka, P. A. D. H. J.; Kumarika, B. M. T.; Jayathilaka, K. M. D. C.; Perera, D.; Liyanage, J.A.; Kalingamudali, S. R. D.Pulse wave analysis (PWA) is a valuable technique for assessing the cardiovascular health of diabetic patients. However, it encounters several challenges, including the complexity of pulse wave signals and the need for standardization and validation of measurement methods. Convolutional Neural Networks (CNNs) play a crucial role in addressing these challenges by offering a robust and accurate approach to classifying pulse wave images. Pulse wave analysis offers a cost-effective, time-efficient, highly accurate, and non-invasive method for diagnosing diabetes-related cardiovascular issues. This study aims to investigate the effectiveness of CNN in classifying finger pulse wave images to accurately distinguish between diabetic and non-diabetic subjects, thus enabling non-invasive diabetes diagnosis. The study's methodology comprises four main steps: data collection, data preprocessing, CNN model development, and model evaluation. Primary data, including finger pulse waves, blood pressure, mean arterial pressure, oxygen saturation, and pulse rate, were acquired from the multipara patient monitor. Subsequently, single pulse wave cycles from 50 healthy individuals and 50 diabetes patients were subjected to preprocessing. The CNN model was developed through data collection, preprocessing, and the creation of its architecture, followed by compilation, training, and evaluation, ultimately achieving a 92% accuracy in classifying pulse wave images for non-invasive diabetes diagnosis. Descriptive statistics were used to summarize participants' demographic and clinical data, revealing no significant differences in age, gender, or body mass index between the two groups. The model's ability to discriminate based on pulse wave images highlights its potential for noninvasive diabetes diagnosis. In order to improve accuracy in future work, increasing the dataset size and conducting hyperparameter tuning will be essential for optimizing the CNN model.Item Morphological and molecular identification of different morphotypes of Suaeda maritima from Puttalam district in Sri Lanka(Faculty of Science, University of Kelaniya Sri Lanka, 2023) Jayasundara, R.; Siridewa, K.; Neththipola, T.; De Silva, W. L.; Perera, D.; Attanayake, R. N.Suaeda is a genus belonging to the family Amaranthaceae (Chenopodiaceae) and comprises more than 100 species that are distributed all over the world. Members of the genus are mainly used for food, feed, and medicine. Three Suaeda species have been reported in Sri Lankan salt marshes among them, S. maritima is widely distributed. During a field survey in Seguwanthive in July 2022, two clearly distinct morphotypes of tentatively identified S. maritima were found. This tentative identification was done purely based on morphological characteristics. One morphotype had green stems and leaves while the other had reddish-green leaves and brightly red-colored stems. No reproductive parts were found at the time of the survey. Even though, previous reports indicated high phenotypic plasticity among the members of the genus, it was not clear whether both morphotypes belonged to the same species or not. Due to the lack of floral structures throughout the year, accurate species identification was a great challenge for a layperson and for a trained taxonomist. Therefore, the current study was conducted to obtain detailed morpho molecular identification of each morphotype of Suaeda maritima, and to confirm their species identity using molecular data as well. Plant samples were collected from Seguwanthive area mainly focusing on two morphotypes and documented. Leaves were succulent, linear in shape, flattened only on one side, and acute in the apex. Plants were 40-65 cm range in height in both morphotypes with a woody base. Flowers were observed only on green plants by the time of sampling, and they were bisexual and contained 5 stamens and 3 stigmas and located axillary in 2 mm diameter clusters and seeds were black, smooth and glossy, and suborbicular to ovoid in shape. Molecular identification was conducted using DNA barcoding approach. Genomic DNA extraction was optimized. The nuclear ribosomal ITS (Internal transcribed spacer) region was PCR (Polymerase chain reaction) amplified using universal primers BLASTn searchers of the sequences confirmed that both morphotypes were identical and 100% similar to previously published records of S. maritima (KF866384). This project findings give insights into the plant’s phenotypic plasticity under its natural environment and can be used as a future guide.Item Development of low-cost automated robot arm; its limitations and the validity of results through modified potentiometric experiments(Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Perera, K. A. N. K.; Rodrigo, S.; Liyanage, I.; Umayanga, I.; Perera, B.; Nawarathne, D.; Perera, D.; Jiffry, N.; Sirimuthu, N.; Ekanayake, E. M. M. S.Robotics is used widely in design, construction and operation, further also in control, sensory, feedback and information processing. Robotics arm performs a crucial task in all the above. Automation in a chemical laboratory will be a major breakthrough in terms of productivity, quality and the reproducibility of the results, improved safety, reduce the time and cost of the whole running process. To catalyze this revolutionized system performances, as a combination of engineering and chemistry, we developed an automated robot arm and validated its results while overlooking the limitations via modified potentiometric experiments. The idea behind this concept is to use this robotics hand in places where it can be used to replicate the action of a human hand and thereby substituting its purpose in places where a human hand cannot be used. During this experiment robot arm involved in measuring cell voltage by using a standard calibrated potentiometer in a thermostat water bath at different temperatures; where it produced steady results compared to the manual procedure under same conditions while saving a considerable working time. The potentiometric reading equipment IEEE 488 fitted with an Interface Scanner 740 and a GPIB (General Purpose Interface Bus) program was used to obtain a continuous record of the potentials while test solutions were moving on a belt. For the validation, reading taken by using the automated arm and manual readings for the same sample were statistically analyzed (n=181) using t-test, linear regression and Spearman correlation coefficients which clearly indicate no significant difference between them. In summary, this work described an inexpensive and simple method for the automated potentiometric titration. The only limitation encountered during this process was the servo motors used, have only a maximum rotation of 180⁰ for 1m radius semicircle within 75s. Therefore, the area of movement is restricted to a certain region of space, but the arm can move an object from one-point coordinate to another in the x, y and z axes which could be adapted to many applications other than in a chemical lab.Item Comparison of different RNA extraction protocols: An optimized RNA extraction protocol for tea leaves [Camellia sinensis (L.) O. Kuntze](4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Keerthika, V.; Ranatunga, M. A. B.; Perera, D.; Herath, H.Extracting high-quality RNA is critical for downstream applications such as quantitative real time PCR (qRT PCR), RNA sequence based transcriptomics and a prerequisite for ensuring representation of all expressed genes in a cDNA library. Tea is a popular non- alcoholic beverage crop and tissues contain abundant polysaccharides, phenolic compounds and other metabolites, which hinder isolation of high-quality RNA. Tender two leaves and a bud harvested is the economically important tissues of tea. A large number of extraction protocols have been exploited or modified for tea, viz commercial kits, CTAB-based methods and SDS-based methods. However; difficulties were encountered in terms of purity and quantity of isolated RNA, while some of the methods were time-consuming. Hence, the present study was aimed to optimize protocol/s for extracting good quality RNA suitable for downstream applications from two leaves and a bud tissue of tea. Two different RNA extractions protocols based on CTAB and hot borate with modifications along with three commercial RNA extraction kits were used to extract RNA from two tea cultivars. Out of which, a CTAB-based protocol optimized for pomegranate plant tissues with minor modifications resulted in the highest RNA yield, varying from 524 ± 4 to 776 ±16 μg/ml for cultivars TRI 2023 and TRI 2025 and high integrity as confirmed by Gel electrophoresis (distinct and visible 28S rRNA and 18S rRNA bands). The extracted RNA was further used for cDNA synthesis, expression of 18s house keeping gene through Realtime-polymerase chain reaction (qRT-PCR). Results showed that the yield and quality of total RNA extracted were suitable for qRT-PCR, depicting the quality of RNA for the downstream applications. Commercially available extraction kits despite of giving sufficient amount of RNA, had lesser yield and quality when compared to the CTAB based method. The protocol optimized for pomegranate was modified with omitting washing the RNA pellet with LiCl and replacing the extraction buffer (CTAB, PVP, NaCl, EDTA, Tris HCl, Spermidine, β-mercaptoethanol) with extraction buffer used for grapevines. This protocol enables successful isolation of RNA from two leaves and a bud tissues of tea within two days without the use of toxic and expensive chemicals such as phenol, guanidium isothiocyanate and guanidium hydrochloride. The protocol is efficient, simple, and reproducible and is therefore recommended for RNA extraction from plants with high polyphenol contentsItem Changes in lung volumes and respiratory muscle strength in different phases of the rowing stroke in Sri Lankan rowers: a preliminary study(Research Symposium on Pure and Applied Sciences, 2018 Faculty of Science, University of Kelaniya, Sri Lanka, 2018) Perera, D.; Ariyasinghe, A. S.; Kariyawasam, A.Breathing is a muscular process brought on by a group of muscles that are capable of demanding as much as 16% of available oxygen during maximal exercise. The rowing stroke consisting of four major phases; catch, drive, finish and recovery are engaged with the breathing cycle. A cross sectional descriptive study was conducted to assess respiratory functions and ergometer performance in 20 male national level rowers in the Sri Lanka Army in the age range 20-35 years in the competition season. Lung volumes and capacities were measured using a portable spirometer (Spiro analyzer ST-75). Respiratory muscle strength (RMS) was measured using a portable hand held mouth pressure meter (Micro MPM, Micro Medical Ltd., Kent, United Kingdom; Precision Medical MPM, UK). Both Lung volumes and RMS were assessed in standing, upright seated, catch and finish positions on the rowing ergometre machine in the morning before training session. Data was analyzed in SPSS software using descriptive statistics and relationship of variables were assessed with Pearson correlation. Probability values < 0.05 were considered significant. Ethical clearance was obtained from Ethics Review Committee, Faculty of Medicine, University of Peradeniya. The lung volumes of peak inspiratory flows (PIF) (2.40 ± 0.61), vital capacity (VC) (8.37 ± 1.66), forced expiratory volume per second (FEV1) (5.80 ± 1.18) and forced vital capacity (FVC)/FEV1 (1.63 ± 2.54) are higher in standing position while peak expiratory flows (PEF) (13.64 ± 1.48) and FVC (6.57 ± 3.17) are higher in finish and catch position on the ergometre machine respectively. Inspiratory muscle strength (IMS) (111.60 ± 29.79) and expiratory muscle strength (EMS) (155.30 ± 33.94) are higher in standing position. EMS and IMS significantly correlated with FVC/FEV1 in finish (r=-0.64; p<0.01) and upright seated (r=-0.56; p<0.01) position in ergometre machine respectively. This study shows that there is a significant association between lung volumes and RMS in phases of rowing stroke rather than in standing position.