dc.contributor.author |
Saverimuttu, J. K. C. |
|
dc.date.accessioned |
2022-03-28T05:15:14Z |
|
dc.date.available |
2022-03-28T05:15:14Z |
|
dc.date.issued |
1999 |
|
dc.identifier.citation |
Colombo : Faculty of medicine, 1999; Degree: Ph.D. |
en_US |
dc.identifier.uri |
http://archive.cmb.ac.lk:8080/xmlui/handle/70130/6531 |
|
dc.description |
A thesis submitted to the University of Colombo for the degree of Doctor of Philosophy |
en_US |
dc.description.abstract |
Several antigens from the microfilarial stage of Wuchereria bancrofti have been
identified using immunoblots of microfilarial antigens and screening with
immune sera and Tropical pulmonary eosinophilia (TPE) sera. This analysis
revealed an array of antigens with apparent molecular weights of 14kD, 35kD,
42kD, 63kD, 88kD, 97kD, and 200kD. Among these only the 14kD and 42kD antigens
were consistently recognized by most of the immune sera. A 132kD antigen was
recognized only by TPE sera. Analysis of rabbit immune sera revealed that the
42kD antigen was shared by two developmental stages of W. bancrofti, namely L3
and mF. This antigen could become a potential vaccine candidate. The 14kD antigen
seems specific for the microfilarial stage and therefore could be a diagnostic
marker for active infection. The 132kD antigen could aid in the diagnosis of
TPE. Screening of a genomic DNA library of W.bancrofti in EMBL3 with the actin
gene of Setaria digitata yielded a clone with an insert size of approximately
13kb. This clone contained the entire actin gene, including the 5' and 3'
flanking regions. The swquences around the 5' and 3' splice sites were fairly
conserved when compared to the eukaryotic consensus sequences and those of
parasitic nematodes. The coding region contained five exons encoding 376
aminoacids and four introns ranging in size from 109 - 190bp. There were no new
intron positions when compared to the positions described to date. Only position
170 - 1 was common to three filarial species Onchocerca volvulus, S.digitata
and W.bancrofti, the only three filarial species in which the actin gene has
been characterized. The W.bancrofti actin aminoacid sequence showed a high
degree of homology to the actins of many organisms from varied taxonomic groups,
but the highest homology was observed with the free-living nematode Plectus
acuminatus. This suggests that P. acuminatus may bare a close evolutionary
relationship to W. bancrofti. At the 5' flanking region, a putative mRNA
initiation site and a potential `TATA' box with the sequence TATAAA could be
identified, though a sequence similar to the ` CAAT ` box could not be identified.
At the 3' flanking region, a potential polyadenylation signal with the sequence
ATTAAA could be identified. The G+C content of the entire gene including the
5' and 3' flanking region was 37.2 percent, whilw the G+C content of the coding
region was 45.18 percent. The introns had an AT content of 70.33 percent. The
codon usage revealed a 63.76 percent preference for T or A in the third position.
A Southern blot analysis of W.bancrofti genomic DNA indicated that the actin
gene is found as a single copy. A detailed analysis of the aminoacid residues
revealed that W. bancrofti actin closely resembles the cytoplasmic actins of
certebrates. |
en_US |
dc.language.iso |
en |
en_US |
dc.publisher |
Faculty of Medicine, University of Colombo |
en_US |
dc.subject |
Wuchereria bancrofti |
en_US |
dc.subject |
Wuchereria bancrofti-genetics |
en_US |
dc.subject |
Wuchereria bancrofti-immunology |
en_US |
dc.subject |
Antigens, Helminth |
en_US |
dc.subject |
Filariasis-immunology |
en_US |
dc.subject |
Filariasis |
en_US |
dc.title |
Analysis of Wucheraria bancrofti Microfilarial antigens and the cloning and chacterization of its action gene |
en_US |
dc.type |
Thesis |
en_US |