PURSE 2004

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Changes in pH Following Freckle Infection (Phyllosticta Musarum) as a Defense Response Against Anthracnose
(University of Peradeniya, 2004-11-10) Weerakoon, A. U.; Adikaram, N. K. B.; Abeysekara, C. L.
The host environment pH is found to be a regulatory factor in pathogenesis of certain fungi. Some fungi increase the host pH while others tend to reduce it. Certain ColLetotrichum spp. have the ability to modulate host pH by secreting ammonia locally into the host tissue, resulting in a pH increase which enables enzymatic secretion and enhance virulence. Colletotrichum musae causes quiescent infections in unripe green banana fruits which develop into anthracnose lesions during fruit ripening. Freckle disease in banana caused by Phyllosticta musarum is associated with a number of defence responses viz. accumulation of phytoalexin and PR proteins, and certain other changes such as lignification and suberization and accumulation of tannins, which in turn reduce the development of anthracnose disease. Six phytoalexins have been isolated from freckle infected banana peel, which contribute to defense against C. musae. The objective of this study was to determine whether P. musarum causes a pH alteration in the banana peel and if so whether this acts as an additional defence response by the fungus against anthracnose. Freckled and non freckled "Embul'' fruits at a similar stage of maturity were obtained from the same bunch. A set of freckled fruits and non freckled fruits were inoculated with 50 III of C. musae spore suspension (105 spores ml") per inoculation, while the control sets of freckled and non freckled fruits were treated with sterile distilled water. Lesion diameters and pH of the peel were measured daily for 7 days. There was a significantly higher anthracnose development in non freckled fruits compared to the freckled fruits. This was observed when fruits were artificially inoculated and also when natural quiescent infections of C. musae were allowed to develop. The freckle infected banana peel had a significantly (p=O.05 level) higher pH than the non freckled peel throughout the ripening process. This indicates that P. musarum infection increases host pH. In fruits inoculated with C. musae, the peel pH was significantly higher (p = 0.05 level) in the freckled peel compared to the non-freckled peel during initial necrosis. Furthermore, at the onset of tissue maceration pH of the freckled peel was higher than that of the non-freckled peel. However with the expansion of lesions the pH in the non-freckled peel was significantly higher at p=0.05 level, when compared to the freckled peel. The higher values of pH in the freckled peel during initial necrosis and the onset of tissue maceration could be a contributing factor in limiting anthracnose in bananas. The increase in pH at an advanced stage of lesion development, in non freckled peel, may be due to rapid tissue maceration caused by C. musae. These results indicate that pH increase following P. musarum infection may be an additional defense response in banana fruit.
An Ecological Study of Grasslands at Hantana
(University of Peradeniya, 2004-11-10) Niroshini, D. M. K. G.; Weerasinghe, H. M. S. P. Madawala
Grasslands of Sri Lanka are ecologically fascinating for their wide floristic, physiological and environmental diversity. Grasslands at Hantana come under humid zone dry patanas. There are many floristic and edaphic variations within these grasslands due to altitude. microclimate, moisture regime, nutrient status. textural properties of soil, human interferences etc. During this study we tried to identify the ecology of grasslands at two different elevations at Hantana and the edaphic factors that may have contributed to this variation. Two grassland sites with an elevation difference of approximately 35 m were selected for this study. Floristic information such as the species composition, density and cover were investigated. Shannon Diversity Index and Evenness values were calculated. Biomass allocation pattern was determined using three 1m x 1m plots. For soil characters, 5 plots (10 m x 10 m each) were randomly selected at each elevation level. In each plot, 12 soil samples were collected randomly from a depth of 0-15 cm, Soil samples were then analyzed for chemical parameters using standard procedures. Panicum maximum (density, 10000 ha-1) is the dominant species at lower elevation grasslands (LoG) while Cymbopogon nardus (density, 8800 ha-1 ) is the dominant species at higher elevation grasslands (HiG). From the total of 18 plant species, 17 % were represented by grasses, 50 % represented by herbs, 22 % by shrubs and 11% represented by treelets in LoG. At HiG, 21 plant species were recorded, and out of that 24% were represented by grasses, 54% were represented by herbs, 19% by shrubs, and 5% by treelets. The Shannon Diversity Index showed that the species richness is higher at HiG than at LoG. The family Poaceae showed the highest cover values in both grasslands (LoG = 44%, HiG = 35%) whereas the family Fabaceae showed the second highest cover values in both grasslands, but it is relatively higher in RiG (33%) than in LoG (29%). The root: shoot ratio of Panicum maximum (0.9460) is higher at LoG than the root: shoot of Cymbopogon nardus (0.7633) at HiG Slightly higher soil pH (6.4) was recorded at LoG compared to HiG (6.0). The total nitrogen (0.2%) and magnesium contents (162 ppm) are significantly higher at HiG than in the LoG (0.15%, 25 ppm respectively) whereas the potassium content is higher at LoG (150 ppm), than HiG (50 ppm). Organic carbon (LoG = 5%, HiG = 5.4%), sodium (LiG = 35 ppm, HiG = 23 ppm) and calcium (LoG = 314 ppm, HiG = 288 ppm) contents are more or less similar in both grasslands. The C: N ratio is close to 30 in both elevations indicating a net immobilization. Results of the present study indicate that the floristic composition and diversity as well as some soil characters differ markedly in these grasslands within this small elevation gradient.
Changes in Women's Role in Families in Mahaweli Resetlements of Sri Lanka: A Sociological Study of System 'C'
(University of Peradeniya Sri Lanka, 2004-11-10) Manuratne, M. G.
This study examines the change in the role of women within the context of families in Teldeniya, a Mahaweli resettlement unit in system 'C' of Sri Lanka. In this study, the role changes of women in the settlement have been examined in comparison to the original villages of the settlers. Intra-community variations of role changes within the settlement were examined in relation to the three family types (allottees, sub-families, and encroachers) and gender. The data were collected using standard anthropological and sociological methodologies involving case studies, observations, interviews and a survey. The study was conducted during the 'Maha' season of October, 1998 to March, 1999. The study found that the women have undergone tremendous change in their roles within the families in the areas of irrigated rice farming, highland cultivation, household chores, activities outside the house, and non-agricultural economic activities. In rice farming, the women work in different types of activities, which outnumbers the activities of the men. This has implications for traditional forms of division of labour. In highland farming, the work becomes the total responsibility of the women, who therefore perform almost all the activities. The women in the settlement perform those activities in addition to what they do at home (household chores), in a context of secluded family, which has tremendously expanded the work 'field' of women from what it has been in the original village. The role changes of women vary with family type, showing that the women in allottee families have undergone most of the changes described above. The study argues, using Bourdieu's concepts of 'field' and 'habitus' that the women in Mahaweli resettlements, although undergoing change in their role within the family, have been much more introvertly structured within the family 'field' than was in the original village. It also refutes the assumption that with the increase in the workload and responsibility, the women in Mahaweli resettlements have liberated themselves. The change in their role within the family has brought in new perspectives of gender relations, which have implications for the occurrence of family crises in Mahaweli settlements.
Canker Disease of Psidium Guajava L. Caused by Pestalotiopsis Psidii and Host Defencive Responses
(University of Peradeniya, 2004-11-10) Bandaranayake, B. M. R. P.; Adikaram, N. K. B.
Canker disease caused by Pestalotiopsis psidii in unripe guava is characterized by browning and cracking of outermost epicarp. Cracking exposes the internal tissues of fruits resulting secondary infections. Infection and development of limited symptoms occur in the field and may develop into progressive fruit rot during ripening. It does not penetrate deeply but reduces the market value. When fruits are severely infected, mummified fruits fall off resulting in yield losses. Causative agent was isolated from the infected areas as well as from healthy internal tissues where symptoms were not visible. The fungus may therefore exist as an endophyte. Healthy and canker infected epicarp tissues of mature and immature fruits were extracted in ethyl acetate for antifungal zones. Four pre-formed antifungal zones were detected on TLC bioassay in healthy tissues. Only two antifungal zones were present in TLC, which was extracted from infected tissues. No additional or larger antifungal zones were present in the extracts taken from infected tissues. Infected tissues observed were yellowish brown in colour and the cells had disintegrated. The infected necrotic tissues did not show deposition of lignin, suberin or tannins. Measurement of pH at the canker infected and healthy areas of the guava fruits, did not show a significant difference. These investigations have revealed that the primary defense response in guava fruit against the canker pathogen brings about rapid necrosis development in which no phytoalaexins were accumulated.
CIM System Expansion With Minimal Changes to Installed Source Code
(University of Peradeniya, 2004-11-10) Dewasurendra, S. D.
The need to upgrade the CIM (Computer Integrated Manufacturing) Systems to provide increased capability in the face of rapid change in product/process specifications has been identified: integration of mechatronic devices such as CNC machines, robot manipulators, automatic assembly systems is a major effort in manufacturing and automation systems, particularly in the face of an increasing demand for these systems to be agile. Agility implies the capability of responding to production changes, both in volume and variety, rapidly, effectively and reliably with low cost. Due to differences in user interfaces to these equipment significant recoding is often needed in response to changes required in production systems. The code that can run into thick volumes has to be verified before installation. Hence, modifying the installed control software to facilitate extension or modification of the system to suit current needs is not straight forward. The present problem is to provide a suitable framework which would facilitate such extension and improvement. In the proposed approach, we wrap already installed software modules in CGI script thus making it possible for them to cooperate with new control modules. The system control is designed and specified using the Universal Modelling Language (UML). In order to provide re-configurability we define port structures between each pair of communicating classes. Verification is localised by having to verify a module using only the information contained in the ports to which it is connected.
Chemistry of Two Leprarioid Lichens from Sri Lanka
(University of Peradeniya, 2004-11-10) Kathiragamanathar, S.; Karunaratne, V.; Kumar, V.
We reported the two species of lichens 𝘓𝘦𝘱𝘳𝘰𝘭𝘰𝘮𝘢 𝘴𝘪𝘱𝘮𝘢𝘯𝘪𝘢𝘯𝘶𝘮 and 𝘓𝘦𝘱𝘳𝘢𝘳𝘪𝘢 𝘢𝘵𝘳𝘰𝘵𝘰𝘮𝘦𝘯𝘵𝘰𝘴𝘢 from Sri Lanka in 2000. The former which was collected from Beragala, was previously reported from South Africa, Colombia and Brazil while the latter, collected from Ramboda, is a new species. The compounds, atranorin 1, β-sitosterol 2, (+)-usnic acid 3, zeorin 4 and a C₋₄₃ fatty acid ester 5 have been isolated previously from the hexane and dichloromethane extracts of 𝘓 𝘴𝘪𝘱𝘮𝘢𝘯𝘪𝘢𝘯𝘶𝘮. In the present study the methanol extract and the lichen powder of this lichen yielded compounds 1-5 in addition to glyceryl trilinolate 6, 3, 6-dimethyl-2-hydroxy-4- methoxybenzoic acid 7 and a triterpenoid 3β-acetoxyfem-9(11)-ene 8. Chromatography of the lichen powder of 𝘓 𝘢𝘵𝘳𝘰𝘵𝘰𝘮𝘦𝘯𝘵𝘰𝘴𝘢 led to the isolation of five compounds, including compounds 1-4 along with methyl-β-orcinolcarboxylate 9. All compounds were characterized by the physical data (mp, TLC and co-TLC) and spectroscopic methods (UV, ¹H NMR, ¹³C NMR, ²D NMR and MS) [The abstract also includes scientific formulas and symbols to represent key concepts and findings].
Clinical Aspects of Oral Lichen Planus in a Group of Sri Lankan Patients
(University of Peradeniya, 2004-11-10) Ariyawardana, A.; Seneviratne, C. J.; Sitheeque, M. A. M.; Ranasinghe, A. W.
The aim of this study was to determine clinical characteristics of oral lichen planus (OLP) in a group of Sri Lankan patients who attended the Dental Hospital for treatment. A total of 104 patients with oral lichen planus who attended the Oral Medicine clinic, Faculty of Dental Sciences, during the period from January 2001 to December 2003 were included in the study. Information pertaining to demographic data, duration of oral lesions and existence of skin lesions were obtained and site and types of the lesions were recorded. Patients with the history of current usage of drugs known to cause lichenoid reactions and with amalgam fillings associated with lesions were excluded from the study. Incisional biopsies were taken from lesions of all the patients in order to confirm the diagnosis. The mean age of the study population at the time of presentation was 45 years and the highest number of cases was found in the age group of 45-55 years (χ²=20.26, df=5, P=O.OO1). Females outnumbered males (1.5: 1). The mean period of experience of the disease before seeking treatment was 4.4 months. 16.3% (n=17) had no symptoms and the rest had feelings of roughness, burning sensation at meal times and spontaneous mucosal burning. There was no gender difference with respect to symptoms (χ²=3.323, df=3, P=O.344). Fourteen patients (13.5%) had shown skin lesions. Six clinical types were identified namely reticular (58.7%), papular (1.9%), plaque like (3.8%), atrophic (2.9%), ulcerative or erosive (6.7%) and lesions with combination of different morphological variants (26%). There was no gender difference with regards to the different clinical types (χ²=5.769, df=5, P=O.329). All patients with atrophic and erosive/ulcerative types had burning sensation as the main symptom. Forty-eight out of 61 patients (78.6%) with reticular type and 19 patients out of 27 (70.3%) with mixed types had burning sensation at meal times. Common sites of affliction were left buccal mucosa (76.9%), right buccal mucosa (75%), dorsum of the tongue (16.3%), lower vermilion border (10.6%) and gingiva (7.7%). The most frequent mucosal combination was the left and right buccal mucosa affecting 66 patients (63.5%). Eighty-seven patients (83.6%) needed therapeutic management and the mainstay of treatment was corticosteroids. Only eight patients (7.7%) needed the use of systemic steroids to control their symptoms. The age and sex distribution of the present cohort resembles that of the other studies on OLP patients. Reticular type was the commonest in the present study and similar results were found in other studies. Buccal mucosa was the commonest site of affliction. There were no cases with evidence of dysplasia or transformed to malignancy. Furthermore, it was not possible to comment on the treatment outcome or the malignant transformation at this stage of the study as the present group of patients is on follow up.
Chemical Constituents of 𝘈𝘳𝘵𝘰𝘤𝘢𝘳𝘱𝘶𝘴 𝘈𝘭𝘵𝘪𝘭𝘪𝘴
(University of Peradeniya Sri Lanka, 2004-11-10) Jayasinghe, U. L. B.; Amarasinghe, N. R.
In a continuation of our studies on search for biologically active compounds from Sri Lankan plants the present study was carried out on the fruits of 𝘈𝘳𝘵𝘰𝘤𝘢𝘳𝘱𝘶𝘴 𝘈𝘭𝘵𝘪𝘭𝘪𝘴 (Park.) Fosb .. 𝘈. 𝘢𝘭𝘵𝘪𝘭𝘪𝘴 of the family Moraceae is a tree of moderate size, commonly known as bread fruit growing in tropical countries[The abstract also includes scientific formulas and symbols to represent key concepts and findings]. The dried powdered fruits of 𝘈𝘳𝘵𝘰𝘤𝘢𝘳𝘱𝘶𝘴 𝘢𝘭𝘵𝘪𝘭𝘪𝘴 were defatted with n-hexane and extracted with ethyl acetate and methanol at room temperature. Preliminary investigation indicated the presence of antifungal active compounds against 𝘊𝘭𝘢𝘥𝘰𝘴𝘱𝘰𝘳𝘪𝘶𝘮 𝘤𝘭𝘢𝘥𝘰𝘴𝘱𝘰𝘳𝘪𝘰𝘪𝘥𝘦𝘴 in both ethyl acetate and methanol extracts in the same Rf region by TLC bioautography method. In order to isolate antifungal active compounds, both ethyl acetate and methanol extracts were combined and separated by a combination of chromatographies over column of silica gel, Sephadex LH-20, reverse phase silica gel and reverse phase HPLC to give seven compounds. Four of them were identified as (𝘌)-4-(3-methyl-E-but-1-enyl)-3,5,2', 4'- tetrahydroxystilbene (1), (𝘌)-3,5,2',4' -tetrahydroxystilbene (2), 2-(2,4-dihydroxyphenyl)- 5,7-dihydroxychroman-4-one (3) and 2-(3,5-dihydroxyphenyl) benzofuran-4, 6-diol (4). Structure elucidation of isolates was based on the detailed analysis of ¹HNMR, ¹³CNMR, MS and direct comparison of the reported data. All these compounds showed radical scavenging properties towards 2,2' -diphenyl-I-picrylhydrazyl (DPPH) radical by TLC bio-autography method. Structure elucidation of the other three compounds and determination of antioxidant activity (IC₅₀) and antifungal activity (MIC) of isolates are in progress.
Chronic Renal Failure in the Medawachchiya-Padaviya Areas: A Geo-Environmental Study
(University of Peradeniya, 2004-11-10) Ileperuma, O. A.; Dharmagunawardhane, H. A.; Herath, K. R. P. K.
While the etiology of the chronic renal failure in the Medawachchiya-Padaviya areas still remains a mystery, some results on the geo-environmental factors of the region reveal some significant findings. A chance discovery made during field studies was that people exclusively use aluminium utensils and that holes were observed in these utensils after continuous use. Water used by these people mostly come from dug wells and they generally have high fluoride content in the range of 1.00-4.00 ppm with a median of around 1.3 ppm. Fluoridation of drinking water is in the midst of a controversy owing to studies, which have shown a direct link between aluminium and fluoride to Alzheimer like symptoms in experimental animals. A cocktail of aluminium and fluoride laced water given to rats showed that the animals develop Alzheimer like symptoms but their premature deaths were attributed to kidney failure. The ability of the aluminofluoride complexes to penetrate the blood-brain barrier has been forwarded as a possible explanation for this observation. The present study aims to establish any relationship between fluoride, aluminium utensils and chronic renal failure. In this study pieces of aluminium from a used aluminium pot were treated with fluoride water containing at different levels of 1.0-4.0 ppm. After two days of standing at room temperature, the amount of aluminium leached was measured by a colorimetric technique (aluminon reagent) to determine uncomplexed aluminium and atomic absorption spectrophotometry to determine total aluminium. The amount of aluminium leached out in the absence of fluoride was 0.43 ppm while in 1 ppm fluoride medium the free aluminium observed was 3.00 ppm where the total aluminium was 11.87 ppm. Surprisingly, the amount of aluminium leached was lower at hgher concentrations of aluminium. This observation is similar to the results from studies on rats where lower concentrations of aluminum fluoride produced more toxic effects than at higher concentrations. In the presence of an acidic medium, using 2g/l of tartaric acid and I ppm fluoride, the aluminium leached was around 56 ppm which is a five-fold increase in the dissolution of aluminium. This experiment was performed owing to the widespread use of acidic ingredients like tomatoes, tamarind, vinegar and limejuice during cooking in aluminium pots. Aluminium leaching under high fluoride stress and acidic spices results in the formation of aluminofluoride complexes such as AlF63., which are soluble and penetrates the blood brain barrier. This stable AlF₆³⁻. complex has an overall formation constant of 6.9 x 10¹⁹ . The observation of both dental and skeletal fluorosis amongst the affected patients gives further credence to the hypothesis that aluminium and fluoride in combination could be a possible reason for the occurrence of chronic renal failure in areas with high fluoride content in water.

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