1,720,961 research outputs found
Phytochemical Screening and In Vitro Antimicrobial Activity of Desmodium triflorum Against Escherichia coli, Enterococcus faecalis, and Klebsiella pneumoniae
Get PDFEmergence of multidrug resistant microorganisms become a major threat to treat gastroenteric diseases. Phytomedicines, derived from diverse medicinal plants in Sri Lanka, offer potent antimicrobial agents against microorganisms, making them a valuable alternative to antibiotics in treating gastroenteric diseases. This study aims to control gastroenteric diseases causing microorganisms by Desmodium triflorum plant extracts. Crude plant extracts were obtained with maceration; using Hexane, Dichloromethane (DCM), Ethyl acetate, Acetone and Methanol solvents separately. Antimicrobial activity of plant extracts was investigated by Kirby-Bauer disk-diffusion method against Klebsiella pneumoniae, Escherichia coli, and Enterococcus faecalis. Zone Of Inhibition (ZOI) was measured and calculated mean ZOI were interpreted based on CLSI zone dimeter breakpoints. All extracts from D. triflorum showed significant difference (P≤0.05) in antimicrobial activity against tested microorganisms. DCM extracts of D. triflorum, showed remarkable in vitro antimicrobial activity by suppressing E. faecalis with the highest mean of ZOI (9.333± 0.577 mm). Minimum inhibitory concentrations (MIC) of DCM extract from D. triflorum were determined by microbroth dilution method. D. triflorum showed MIC of 10.5 mg/mL for K. pneumoniae, 21 mg/mL for E. coli, and 21 mg/mL for E. faecalis. Preliminary phytochemical analysis revealed the presence of terpenoids in hexane extract, alkaloids, terpenoids, saponins in DCM extract, alkaloids, saponins in ethyl acetate extract, alkaloids, saponins in acetone extract, and phenols, tannins, alkaloids, saponins, terpenoids, flavonoids in methanol extract obtained from D. triflorum. DCM extract of D. triflorum was subjected to GC–MS analysis to identify the likely compounds responsible for the antimicrobial properties. Ten compounds in D. triflorum were identified as potential contributors to its antimicrobial activity. The highest percentage of total observed as n[1]Hexadecanoic acid which is 3.927%. Present study concludes DCM is the most effective solvent for solubilizing antimicrobial compounds. The highest inhibitory action of D. triflorum was demonstrated against E. faecalis. Isolated active compounds from D. triflorum will be a potential source for the synthesis of novel drugs to control the pathogenicity of E. faecalis by addressing multidrug resistance in gastroenteric microorganisms.
Keywords: Desmodium triflorum, Multidrug resistant, Antimicrobial activity, DCM extract, GC-MS analysi
Pollen Morphological Studies on Selected Species of Family Dilleniaceae in Sri Lanka
Get PDFDilleniaceae is an angiosperm family including 11 genera and about 500 known species with a pantropical distribution extending into Australia. In Sri Lanka, four genera and 16 species including one introduced species have been reported in the family Dilleniaceae. Most of these species are endemic or native, while Schumacheria is an endemic genus. Morphological characters of the pollen grains are a significant taxonomic identification tool in the systematics of higher plants. The aim of the study is to provide detailed palynological descriptions of selected pollen species and maintain pollen reference collection. Four plant species, Dillenia retusa, Dillenia suffruticosa, Dillenia triquetra, and Schumacheria castaneifolia of the family Dilleniaceae (Genus Dillenia and Schumacheria) were collected from different localities in the wet zone including Nugegoda and Baduraliya during the period from September 2022 to November 2022. The voucher specimens were authenticated using revised handbook to the flora of Ceylon and deposited in the Herbarium of the Department of Botany, University of Sri Jayewardenepura, Sri Lanka. Fresh flowers or dried flowers were taken to collect pollen. Pollen grains were acetolysed and observed under Optika microscope (BG-Italy) after mounting on a clean glass slide using glycerin jelly with Basic fuchsin. Thirty pollen grains were used to determine the pollen size for each selected species. All measurements were taken within seven days of pollen preparation using OptikalSview (3.9.0.604) software. The shape, size, and surface features of pollen grains, as well as the length and width of the pollen and apertures and Polar/Equatorial ratios, were observed. Descriptive statistical analysis was performed using Minitab 18 software for the quantitative variables related to measurements of pollen obtained with light microscope. The ranges of variation were 15-22 μm for polar axis, 16-26 μm for equatorial axis, 0.8-3.5 μm for colpus width and 5.0-12.5 μm for colpus length. The pollen grains of all the species are monad, isopolar, and radially symmetrical. Pollen grains were identified as suboblate to oblate spheroidal, small or medium-sized, tricolpate (Dillenia spp.) or tetra-colpate (Schumacheria castaneifolia), with the surface ornamentation punctate to reticulate. The longest and widest pollen grains were reported in Dillenia suffruticosa (22.0×26.4 μm), while the smallest were observed in Schumacheria castaneifolia (15.2×16.4 μm). Based on the length of the longest spore axis, except D. suffruticosa all other species are categorized into small-size pollen. According to the results, the distinction between species can be determined using palynological features such as shape, size, and aperture type.
Keywords: Pollen morphology, Dilleniaceae, Palynology, Reference collection 
Comparative Analysis of Metal Accumulation in Selected Plants as an Indicator of Environmental Pollution
Get PDFHarmful pollutants of vehicular emissions contribute to the environmental contamination of heavy metals, leading to adverse effects on plant and animal species. The presence of roadside plants has the potential to absorb significant quantities of heavy metals, presenting a possible solution for mitigating heavy metal pollution. Therefore, the current study was undertaken to comparatively determine the ability of certain plant species commonly growing along roadsides to absorb and accumulate heavy metals. It was aimed to assess the concentrations of the specified metals Pb, Cu, Zn, Mn, and Fe in leaf samples of the species, Mangifera indica, Polyalthia longifolia, Delonix regia, Cassia fistula, and Mesua ferrea, on the roadside and inside the premises, of the University of Sri Jayewardenepura, Sri Lanka. The analysis was done using AAS and the results were analyzed and compared through one-way ANOVA, using Minitab-21. According to the results, M. indica accumulated a significant amount of Pb, Cu, Zn, and Mn. P. longifolia accumulated a high level of Mn. A significant Zn accumulation was observed in C. fistula and the highest accumulation of Fe was observed in M. ferrea. D. regia accumulated a comparatively high amount of Cu and Zn. The heavy metal accumulation pattern in all roadside plants was Mn>Fe>Zn>Cu>Pb. From the results, it was observed that the plants alongside roads show bioaccumulation of a substantial quantity of heavy metals than those growing inside the premise, with a lower exposure to vehicular emissions. Since the environmental conditions were similar in both sites, it can be suggested that observed changes in the metal contents may be due to the effect of vehicular emissions. Based on the level of accumulation, each plant species could be considered a hyperaccumulator for the specific heavy metals. From the species analysed, M. indica accumulated the highest content of heavy metals, thus it could be considered a suitable accumulator, to be grown on traffic-dense roadsides, and other species could be used in mitigating metal-related pollution in other contaminated areas.
Keywords: Vehicular, pollution, Traffic, Roadside, Biomonitoring
 
Monitoring of the Airborne Pollen Diversity at the University of Sri Jayewardenepura Premises
No full textStudying airborne pollen grains and other microscopic organic particles present in the atmosphere is critical in understanding pollen and spore dispersion, and their seasonal distribution. This has substantial implications for environmental and allergenic research studies. In this study, pollen sampling was carried out using a self-modified gravimetric (Durham type) pollen sampler for six months, from July 2022 to December 2022. The pollen trap was placed and two microscopic slides were installed at a height of 1m above ground level at the garden of the Department of Botany, University of Sri Jayewardenepura, to investigate the airborne pollen species within the premises. One microscopic slide was coated with Vaseline, while the other was coated with Glycerin jelly with basic fuchsin. The slides were replaced weekly to analyse the quantity of pollen dispersed around the sampler. The collected pollen grains were mounted with glycerin jelly with basic fuchsin and observed under a light microscope using 400x magnification. Pollen concentrations were obtained by counting ten longitudinal transects, which resulted in the screening of about 23.5% of the total surface of the slide and converted to pollen grains/cm2 of the implication surface of the slide. In this study, 639 pollen grains/cm2 were recorded in a microscopic slide coated with Glycerin jelly with fuchsin while 676 pollen grains/cm2 were recorded in a slide coated with Vaseline. As the most abundant pollen type, pollen grains of Poaceae (including genera of Sporobolus, Chrysopogon, Heteropogon, Eleusine, etc.) comprised 62.44% of the total pollen content and the highest count occurred in December, with 30.3% of the total pollen content in the Glycerine slide. In the Vaseline slide, Poaceae showed 65.98% of the total pollen content and the highest number of Poaceae pollen in December (37.9%). Pollen type A (12.6% and 10.8%), and Casuarina equisetifolia (3.7% and 2.8%) were the other dominant species in both Glycerin and Vaseline media slides, respectively. Acacia auriculiformis, Azadiracta indica, Hibiscus rosasinensis, Syzygium spp., Dendrophthoe sp., Alternanthera sp., and Eleocarpus serratus and genera of family Asteraceae, Menispermaceae and Arecaceae, were the other identified pollen types recorded in the period of study. The highest number of pollen grain concentrations from the total pollen contents (Glycerine sample: 41.47% and Vaselline sample: 50.16%) were recorded during December. This study helps to extend the knowledge of airborne pollen diversity at the University premises of Sri Jayewardenepura.
Keywords: Aeropalynology, Airborne pollen, Gravimetric sampler, Pollen diversity, Pollen concentratio
Review of Utilizing the Phytochemicals of Ocimum sanctum and Plectranthus amboinicus for Novel Herbal Product Development in Sri Lanka
Get PDFOcimum sanctum (OS) and Plectranthus amboinicus (PA) are two highly abundant medicinal plants in the Lamiaceae family. Despite their widespread availability and documented ethnomedicinal uses, scientific awareness of their pharmacological potential is restricted in Sri Lanka. Consequently, their utilization in herbal products remains limited. The present review investigates the scientific evidence on phytochemical constituents in those species and their potential in novel herbal product development in Sri Lanka. The review was conducted based on indexed journal articles published in the last 15 years. Based on the available data, OS’s main phytochemicals involved in pharmacological activities are eugenol, methyl eugenol, rosmarinic acid and apigenin. Eugenol, the main component in OS essential oil, demonstrated 97% inhibition of the COX-I enzyme responsible for plants’ anti-inflammatory properties. It has significant antifungal activity, particularly against Candida species. According to several studies, the essential oil of OS prevents morphological changes in C. albicans, reduces the secretion of hydrolytic enzymes crucial in the infection’s early stage, and downregulates the genes connected with the infection. Rosmarinic acid, the principal constituent in ethanolic extracts of OS, exhibits anti-ageing properties by inhibiting collagenase, elastase, and hyaluronidase. OS could be a renewable source of eugenol and rosmarinic acid with high potential to be utilized in antifungal, anti-inflammatory topical applications and anti[1]ageing cosmeceuticals in Sri Lanka. PA contains phenolics, volatile compounds, and abietene diterpenoids as its predominant phytochemicals. Its essential oil, rich in volatile compounds like carvacrol and thymol, displays promising activity against bacteria and fungi, with minimum inhibitory concentration (MIC) values around 50 µg/mL in various studies. Furthermore, PA essential oil exhibits anti-inflammatory capabilities comparable to the conventional drug Diclofenac. Additionally, its phytochemicals possess a wide range of biological properties, effective in treating respiratory, cardiovascular, oral, skin, digestive, and urinary diseases. Hence, the phytochemicals of PA present valuable potential as sources for novel anti-inflammatory and antimicrobial herbal products, especially for skin and respiratory disorders. Based on data, phytochemicals in OS and PA have the potential to be used in a variety of novel herbal products. Both plants have higher growth rates and can be easily cultivated. Thus, developing novel herbal products that utilize the phytochemicals of OS and PA could be highly feasible and cost-effective. This review provides valuable insights and stimulates future research to focus on utilizing OS and PA phytochemicals in novel, sustainable herbal product lines, contributing to improved healthcare and well-being in Sri Lanka.
Keywords: Ocimum sanctum, Plectranthus amboinicus, Phytochemicals, Herbal products, Pharmacologica
Comparative Study of Soil Nutrients in Selected Paddy Lands in Wet Zone Treated with Organic and Chemical Fertilizers
Get PDFIn Sri Lanka, paddy consumes the most significant part of chemical fertilizers and accounts for approximately 50 percent of the widespread use of chemical fertilizers. With the immediate banning of inorganic fertilizers, there was a huge argument between the government and the farmers about organic farming. Since the soil fertility change takes a long time, the impact of long-term application of the same fertilizer should be assessed. Field experiments were conducted in six selected paddy fields in wet zone considering fertilizer type and rice variety. Total 30 samples from each site were collected and soil initial nitrogen (N), phosphorus (P) potassium (K), Organic C, and composition of used fertilizers were analyzed. Nutrient status compared using critical, optimum ranges, and general management practices are discussed. This study revealed that the total N level in all the sites varies near the critical level and is inadequate to produce expected yields. Soil organic C (3.8-6.7%) and N (0.06-0.2%) levels in organic sites were higher than the chemical sites (0.09-0.19N%, 1.4-2.1C%). Phosphorus level is below the critical level (0.9-8.4 mg/kg) in organic sites, and varies from medium to high (7.5-27.0 mg/kg) in chemical sites. The sites using chemical fertilizers showed excessive K (395-480 mg/kg), and organic sites were below the optimum range (82-92 mg/kg). According to the fertilizer analysis, organic fertilizers are rich in organic C (40-90 g/kg), while organic C is absent (0%) in chemical fertilizers. All the other nutrient amounts are very low (N:0.7-19.3 g/kg, P:0.06-0.8 g/kg, K:33.2-15.4 mg/kg) in organic fertilizers, and the composition is unstable. Chemical fertilizers have an exact composition of nutrients and can easily be applied at the particular growth stage of the plant which is beneficial. An external supply of essential soil nutrient through organic or chemical fertilizer sources is required to produce expected yields. Regular and continuous monitoring of soil quality, pre-nutrient assessment of organic fertilizers, site-specific fertilization, and proper agronomic practices are highly recommended. These results will be beneficial in selecting or manufacturing suitable fertilizer type/types for paddy cultivation, including bio-fertilizers.
Keywords: Organic fertilizers, Status of soil nutrients, Soil fertility, Rice varietie
Investigation of Some Selected Rice Landraces for C4 Photosynthetic Traits
No full textAchieving food security amidst rapid climate change necessitates an increase in rice production, a crucial food crop for over half of the global population. One promising approach in this regard is the introduction of the more efficient C4 photosynthesis into the rice plant, which is driven by C3 photosynthesis. However, despite numerous attempts, the absence of a leaf anatomy compatible with C4 photosynthesis still acts as a major roadblock to successfully implement the complex C4 biochemistry into the rice plant, and the identification of phenotypes with a naturally occurring C4-like leaf anatomy could potentially act as a stepping stone in the introduction of C4 photosynthesis into rice. Therefore, this study aims to investigate some selected Sri Lankan rice landraces for the presence of C4-like leaf anatomical characteristics, such as high leaf vein density, reduced mesophyll cell number, and low stomatal density, by comparing them with those of two representative C4 grass species, Setaria italica and Echinochloa colona. Leaf samples were collected and fixed six weeks post transplantation. For the measurement of vein density, leaf sections were cleared using a KOH gradient, and stomatal density measurement was carried out on both nail polish stomatal imprints and leaf sections cleared using an 85% Lactic acid: 1% chloral hydrate solution, depending on the species. Mesophyll cell counts were taken by clearing leaf sections using the same clearing solution. All the measurements were carried out on the photomicrographs captured using a digital light microscope. Each of these measurements were represented by 15 measurements of five leaf blades taken from five different plants. Our findings highlighted that, despite none of the landraces showing comparable leaf anatomical characteristics to S. italica and E. colona, interestingly, Pachchaperumal stood out for its highest vein density, lowest mesophyll cell number, and relatively lower stomatal density among the rice landraces tested, showing a possible adaptation to reduce transpiration and maintain the hydraulic integrity in the hot tropical microclimate of Sri Lanka, similar to the conditions under which C4 photosynthesis evolved. Apart from that, in our study, two other landraces, Hondarawalu and Niyanwee, were also selected as high vein density candidates. Overall, we present three candidates as a germplasm source for future studies in understanding the establishment of C4-compatible leaf anatomy in a C3 rice plant, namely, Hondarawalu, Niyanwee, and especially, Pachchaperumal, which could meaningfully contribute to the ongoing work of the development of C4 rice.
Keywords: Food security, C4 photosynthesis, C4 rice, rice landraces, C4 leaf anatom
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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