Gaya Ranawaka

The Open University of Sri Lanka | OUSL · Department of Zoology

This study investigated genetic linkage, recombination fractions and mutation rates of 16 X chromosomal short tandem repeat (X-STR) markers using a recently developed multiplex PCR assay for Sinhalese population of Sri Lanka, by analyzing 81 three-generation families including 81 grandfathers with daughters and 162 grandsons. In addition, 31 two ge...

A new 16 X-short tandem repeat (STR) multiplex PCR system has recently been developed for Sr Lankans, though its applicability in evolutionary genetics and forensic investigations has not been thoroughly assessed. In this study, 838 unrelated individuals covering all four major ethnic groups (Sinhalese, Sri Lankan Tamils, Indian Tamils and Moors) i...

A new 16 X- short tandem repeat (STR) multiplex PCR system has recently been developed for Sr Lankans, though its applicability in evolutionary genetics and forensic investigations has not been thoroughly assessed. In this study, 838 unrelated individuals covering all four major ethnic groups (Sinhalese, Sri Lankan Tamils, Indian Tamils and Moors)...

The study describes the development of a new multiplex PCR system that simultaneously amplifies 16 X chromosome short tandem repeats (X-STRs) loci in a single PCR reaction and its applicability on a sample of 200 from the Sinhalese population in Sri Lanka. 13 X-STR loci located in four clusters are selected for the assay (DXS10148-DXS10135-DXS8378,...

1. The Pelopidas are a widely distributed genus of hesperiids ranging from the Afrotropical to Australasia. Based on traditional classification, four species are recorded from Sri Lanka: Pelopidas agna, P. mathias, P. subochracea and P. conjuncta. 2. The aim is to test the taxonomic hypotheses of the Sri Lankan Pelopidas as they are currently reco...

Sri Lanka, together with the Western Ghats, is one of the world's biodiversity hotspots, yet little is known about the genetic diversity of the butterflies here. Within the framework of the recently reconstructed molecular phylogeny for the subtribe Mycalesina, we determined the phylogenetic relationships and biogeographic history of the five specie...

Morphological variability among four species of Mycalesis in Sri Lanka that are difficult to discriminate due to their morphological similarity was investigated to identify characters that distinguish species more accurately. Using traditional morphometrics, 90 variables from the wing, forelegs and genitalia of M. perseus typhlus, M. mineus polydec...

Purpose The purpose of this paper is to illustrate the development and testing of an innovative mobile application using design-based research. Design/methodology/approach This paper reports on the process of transformation of existing printed course material into digitized content through design-based research where design, research and practic...

Sri Lanka has eliminated malaria transmission to zero indigenous malaria cases since October 2012. Currently, the biggest threat to the elimination efforts is the risk of resurgence due to imported malaria. In 2012 there were 70 imported cases. This was followed by 95, 49 and 36 imported cases in 2013, 2014 and 2015, respectively. The majority of i...

Background: The genus Mycalesis consists over a hundred species spread throughout the Australasian region. Of these, M. perseus, M. patnia, M. mineus, M. subdita and M. rama are the species found in Sri Lanka, with the latter two being endemic to the island. The Sri Lankan populations of M. perseus, M. mineus and M. patnia are closely related to t...

Mycalesis perseus, M. mineus, M. patnia and M. subdita are four butterfly species found in Sri Lanka with overlapping morphological boundaries. This study examined their morphology through the observation of 185 field caught adult specimens. A discriminant analysis was performed on 29 morphometric variables from wing, genital and foreleg characters...

Genus Mycalesis shows a spectacular radiation of over a 100 species spread throughout the Australasian region. 5 of these species are found in Sri Lanka with two endemic (M. rama and M. subdita). This paper presents the preliminary morphometric data obtained for Mycalesis populations in Sri Lanka with respect to selected wing, genital and foreleg c...

Short tandem repeats (STRs) are a group of highly polymorphic loci in the human genome. STR loci consist of tandemly repeated sequences of 2-7 base pairs in length. As they are small in size STR loci can easily be amplified by the polymerase chain reaction (PCR). Allele frequencies of short tandem repeat loci D3S1358, D5S818, D8S1179 were analyzed...

During mosquito transmission, malaria ookinetes must cross a chitin-containing structure known as the peritrophic matrix (PM), which surrounds the infected blood meal in the mosquito midgut. In turn, ookinetes produce multiple chitinase activities presumably aimed at disrupting this physical barrier to allow ookinete invasion of the midgut epitheli...

The impact of immune sera, and peripheral blood cells (PBC) from mice immunized with Plasmodium berghei ookinetes; and of purified immunoglobulin or Fab fragments from anti-Pbs21 monoclonal antibody 13.1, upon establishment of oocyst infections in the mosquito was studied. Infections were initiated either from gametocyte-infected mice, or membrane...

The transmission-blocking monoclonal antibody 13.1, which recognizes the ookinete surface antigen Pbs21 of Plasmodium berghei, and an IgG2a isotype control antibody 26.37 were purified by caprylic acid and ammonium sulphate precipitation. Fab fragments were prepared by papain digestion. IgG but not Fab from antibody 13.1 reduced ookinete formation...

The effects of purified monoclonal immunoglobulins from control, or transmission-blocking anti-Pbs21 antibodies, upon the infection of Anopheles stephensi by ookinetes of Plasmodium berghei are compared. Anti-Phs21 antibody reduced mean intensity and prevalence of infection by 94·7 and 58·7% respectively if added to the infectious bloodfeed at a co...

Confocal scanning laser microscopy has been used to study the distribution of antigens expressed by the liver stages of Plasmodium berghei in cultured hepatoma cells. The 3-dimensional images obtained of intact parasites clearly show complex patterns of antigen expression not apparent when using conventional IFAT or immunoelectron microscopy. A liv...