Browsing by Author "Dunuwille, S.W.M.B."

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    Assessment of the antibacterial activity and genetic diversity of three black pepper varieties (Piper nigrum Linn.)
    (Uva Wellassa University of Sri Lanka, 2013) Karunathilaka, K.A.S.; Pathirana, P.R.S.; Rajapaksha, I.G.M.; Thilakarathne, L.; Heenkenda, A.P.; Senevirathne, J.M.; Dunuwille, S.W.M.B.; Sooriyapathirana, S.D.S.S.
    Piper nigrum (black pepper) is an important spice to enhance flavor, color, aroma and taste of food. Black pepper is also considered as a medicinal plant species which is used to treat asthma, chronic indigestion, obesity, sinus, congestion and fever (Ravindran, 2000). It has an antibacterial activity further highlighting its medicinal importance (Dorman and Dean, 2000). In Sri Lanka, black pepper is considered as one of the important export agricultural crops. However, neither medicinal properties nor the antibacterial effect of pepper in Sri Lankan pepper germplasm has been studied in detail. In neighboring India, there were reports on the antibacterial activity of pepper on Bacillus cereus and Bacillus subtilis (Perez and Anesini, 1994). According to Chaudhry and Tariq, (2006) “piperine, ([1-[5-[1, 3-benzodioxol-5-yl]-1- oxo-2, 4, pentadienylpiperridine), a pungent alkaloid present in black pepper enhances the bioavailability of various structurally and therapeutically diverse drugs”. The genetic diversity of pepper germplasm has been studied using Inter-Simple Sequence Repeat (ISSR) markers, microsatellite markers and Randomly Amplified Polymorphic DNA (RAPD) markers. The present study was conducted to assess the antibacterial activity of pepper oleoresin (an extract from pepper) from three varieties of P. nigrum in Sri Lanka and also to assess their genetic diversity using RAPD markers. Methodology P. nigrum samples: three P. nigrum varieties, Panniyur-1, MB12 and GK49 were used for the analysis. Seeds were collected from these three varieties to extract oleoresin and young leaves were picked to extract DNA. The samples were collected from Central Research Station, Department of Export Agriculture, Matale, Sri Lanka. Preparation of oleoresin: pepper seeds were ground into a fine powder using a mechanical grinder. Ten grams of powder was weighed and filled into a thimble. The thimble was placed in a Soxhelt apparatus and was exposed to several cycles of distillation. The concentrated solution was rotary evaporated to extract the oleoresin. Evaluation of the antibacterial activity: the antibacterial activity of pepper oleoresin against Escherichia coli (Ingerson-Mahar and Reid, 2011) and Staphylococcus aureus using agar well diffusion method. Mueller Hinton agar plates were prepared. The two strains of microbial solution were prepared with compared to the 0.5 McFarland solution and then they were spreaded on the agar surfaces. Wells were cut by using sterile cork borer and bottom of the wells was sealed with a little bit of medium. Pepper oleoresins were loaded in to the wells by using a micropipette and petri dishes were finally incubated at 37 C for overnight in an incubator.
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    Development of a PCR based genotyping procedure to identify the adulterations to beef in Sri Lankan meat market
    (Uva Wellassa University of Sri Lanka, 2013) Dunuwille, S.W.M.B.; Premachandra, T.N.; Rajapaksha, P.; Rajapakse, S.; Sooriyapathirana, S.D.S.S.; Jayawardane, B.C.; Himali, S.M.C.; Kodithuwakku, S.
    Meat is consumed by the Sri Lankan people as a major source of dietary protein. Meat contains over 20 different proteins with a high biological value and contains almost all the essential amino acids (Vercoe et al., 1997). Substitution of an expensive meat type with a cheaper or unaccepted meat type is a major problem associated with the meat industry. Therefore, the determination of food authenticity and the detection of adulteration are important to protect consumer rights (Gupta et al., 2012). Identification of the species of origin of the meat sample is relevant to consumers for several reasons such as possible economic loss due to fraudulent adulterations, medical requirements of individuals who might have specific allergies and religious reasons (Miguel et al., 2004). The beef industry in Sri Lanka is relatively small scale when compared with other countries. The per-capita availability of beef was 1.71 Kg/year in 2011 (Department of Animal Production and Health, 2011). However, a considerable amount of the Sri Lankan population consumes beef and the potential for beef to be substituted by other meat types is higher. Buffaloes are considered as a protected species in Sri Lanka and therefore slaughtering is banned (Animal act, 1958). However, Buffalo meat is often used to adulterate beef. This is mainly because Buffalo meat is comparable to beef in many of the physicochemical, nutritional, functional properties and palatable attributes (Anjaneyulu et al., 1990). Apart from taking buffalo meat as a possible adulterant of beef, this study also tried to distinguish goat meat and dog meat from beef as well using DNA fingerprinting approaches. Methodology Sample collection and DNA extraction: blood samples from Cattle, Goat and Dog and a Buffalo meat sample was obtained. Blood samples were stored at 4°C and meat samples were stored at - 20°C. DNA was extracted from blood samples using the Phenol-Chloroform-Isoamyl alcohol method with modifications (Sambrook and Russell, 2001). DNA was extracted from the meat sample using the Promega Wizard SV Genomic DNA Purification System. DNA samples were quantified using UV absorption spectrophotometer at 260 nm. By using the quantified DNA solutions, working DNA solutions with the concentration of 60 ng/µl were prepared.