EXPRESSION PATTERN OF TRANS-SIALIDASE GENES IN THE LIFE CYCLE OF TRYPANOSOMA CONGOLENSE.
EXPRESSION PATTERN OF TRANS-SIALIDASE GENES IN THE LIFE CYCLE OF TRYPANOSOMA CONGOLENSE.
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Date
2015-04
Authors
CHECHET, GLORIA DADA
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Abstract
Trypanosoma congolense an agent of Nagana, the trypanosomiasis in African ruminants remains a threat throughout sub-Sahara Africa, and new approaches to disease prevention and treatment remain a priority. Trypanosomes express an enzyme called trans-sialidase (TS; E.C. 3.2.1.18), which is believed to play an important role in maintaining pathogenicity of the parasites. Data of Expressed Sequence Tag sequences obtained from T.congolense cultures made available through the Welcome Trust Sanger Institute web site (www.sanger.ac.uk/Projects/T_congolense/) have suggested that the TS-like genes identified in the genome are differentially expressed in procylic, metacyclic, epimastigote and blood stream parasites. In order to test the hypothesis that trans-sialidase (TS) and TS-like gene p roducts play a role in the infection cycle of T. congolense, the transcription pattern of TS genes during the entire life cycle of Trypanosoma congolense, i.e. during the manifestation of infection in a suitable host and the maturation of parasites in the flies has been investigated. To establish the infection cycle, an experimental rat carrying Trypanosoma congolense was made available for tsetse flies (Glossina morsitans morsitans) to feed on to aquire infection. These infected flies were fed on clean goats. Generic PCR analysis for identification due to the reason that inter-species size variation in the PCR product of the internal transcribed spacer (ITS-1) region of ribosomal RNA repeat region enables species identification. Species-specific tests were used to confirm these identifications. Due to it‘s improved sensitivity, this method facilitated identification of various trypanosoma species and monitoring the infection cycle of Trypanosoma congolense in the mammalian host and fly vector reflecting the parasitic status of the infected tsetse flies. Samples for analysis by Reverse transctiptase Polymerase chain, reaction (RT-PCR), Western blot and Quantitative polymerase chain reaction (qPCR) were obtained from fly tissues dissected 21 days post infection and blood collected daily from the goats. Contrary to previous reports,the RT-PCR, Western blot and qPCR results clearly show that Trans-sialidase genes are expressed in the blood stream and procyclic forms and are developmentally regulated.
Description
A DISSERTATION SUBMITTED TO THE SCHOOL OF POST GRADUATE STUDIES, AHMADU BELLO UNIVERSITY IN PARTIAL FULFILMENT FOR THE AWARD OF PhD BIOCHEMISTRY.
Keywords
EXPRESSION,, PATTERN,, TRANS-SIALIDASE,, GENES,, LIFE CYCLE,, TRYPANOSOMA,, CONGOLENSE.