IRSPAS 2017
Permanent URI for this collectionhttp://repository.kln.ac.lk/handle/123456789/18078
Browse
2 results
Search Results
Item Rumen microbiome: Exploring the adaptive roles of viruses and bacteria in the rumen.(International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Anderson, C. L.; Fernando, S.C.Complex and diverse microbial communities mediate the cycling of nutrients within ruminants. The structure of this complex microbial community is shaped by the highly variable physical, chemical and predatory environment. In turn, the microbial community regulates the environment and nutrient cycling including the export of energy to the host in the form of volatile fatty acids. The diversity of the enteric microbial community is both ecologically and biochemically important. In addition to the important role of the rumen microbiome on its host, the anaerobic conversion of complex organic matter to methane in ruminants is an essential link in the global carbon cycle, and has a significant contribution towards global warming and climate change. However, our understanding of the rumen microbial community structure and function is in its infancy and we are just starting to understand microbial community structure within ruminants. As a first attempt to better understand the influence of viruses on host bacterial populations, we investigated viral and total, microbial community structure and function using metagenomic shotgun sequencing under changing dietary conditions. When a shared read approach and protein clusters were used, the structure of total microbial communities significantly differed based on diet and host, while viral metagenomes differed only by diet. Using community level metabolic networks, we further explored why different diets enrich phage communities for specific metabolic pathways. Enzymes differentially abundant in the total metagenome and virome were more centrally located and a shorter path length compared to non-differential genes in the network. This ongoing work begins to suggest diet, rather than host factors, has a strong influence on the structuring of rumen phage populations and that phages encode for an adaptive repository of central metabolic functions related to selection pressures driven by altering environmental conditions. Current efforts are focused on better understanding what governs, why certain central metabolic genes are enriched and how this is related to the flow of information through metabolic networks.Item Endophytic bacterial diversity of mangrove leaves.(International Research Symposium on Pure and Applied Sciences, 2017 Faculty of Science, University of Kelaniya, Sri Lanka., 2017) Gunathunga, S.U.; Rathnayake, V.N.Endophytes are by definition, the microorganisms that reside in the plant tissues, colonizing locally as well as systemically, without causing any harm to the particular plant. Both the plant and its endophytes have benefits for each other, hence this is called a mutualistic relationship, where both species gain advantage. Considering the scarcity of records regarding mangrove endophytic bacteria in Sri Lanka, a preliminary study was carried out using four true mangrove species from “Kadol kale” mangrove forest (Negombo, Sri Lanka). There are two groups of mangroves; major mangrove species and mangrove associates. Major mangroves are true mangrove species that grow only in mangrove environment, while mangrove associates are found in within or in peripheral areas of mangrove forests. Mangrove species, namely Avicennia marina, Brugeira gymnorhiza, Lumnitzera racemosa and Rhizophora mucronata were selected with the objective of isolating and determining endophytic bacterial diversity of mangrove leaves. For the isolation of endophytes, the healthy mature leaves were surface sterilized, and bacteria from inner tissues were extracted using a buffer and inoculated in to Tryptone Soy Agar medium using spread plate technique and plates were incubated for 1 week at 30 °C. Fifty bacterial isolates were obtained according to their phenotypical attributes. Morphological, cultural and some biochemical characteristics of these isolates were studied and according to Bergey’s manual of determinative bacteriology, isolates were grouped in to their generic level. A total of 17 isolates from Avicennia marina (AM), 17 isolates from Brugeira gymnorhiza (BG), 11 isolates from Lumnitzera racemose (LR) and 5 isolates from Rhizophora mucronata (RM) were obtained. Majority of the isolates were belonged to the genus Bacillus and rest of the isolates belonged to genus Aerococcus, Corynebacterium, Staphylococcus, Enterobacter, Rothia and Micrococcus.