The Mycobacteria are a genus of bacteria which are acid-fast, non-motile,
grampositive rods. The genus comprises several species classified into three main
groups. Firstly, the major group of these organisms, which poses the biggest threat, is
the M. tuberculosis complex which can cause tuberculosis-like disease. These include
M. bovis, M. africanum and M. microti. Members of the M. tuberculosis complex are
not found in the environment. The second group is M. leprae which is the causative
agent of leprosy. The last group constitutes the nontuberculous mycobacteria (NTM),
which are all the environmental mycobacteria that can cause various diseases
resembling tuberculosis. Due to the importance of environmental mycobacteria, 15
mycobacteria isolates were isolated from environmental samples such as soil, water
and drinking water biofilms. After PCR amplification of the hsp65 gene using genus
specific primers hsp65, the isolates revealed sequences similarities when compared
with the well characterized mycobacteria in the GenBank. Alignment of the
nucleotide sequences and homology analysis were done with Clustall. It has been
suggested that mycobacteria-associated phages (mycobacteriophages) may make an
important contribution to the evolution of pathogenic mycobacteria. Spontaneous
induction of phage associated with mycobacteria isolates using overlay and indicator
plate methods was not successful to detect the presence of any inducible phage. A
phage was isolated from soil samples that was designated the name A22. After
purification and characterization. A22 phage was compared morphologically to well
characterized L5 phage using electron microscopy. Morphological studies revealed
that A22 mycobacteriophage had a non-contractile tail approximately 150 nm long
with an isometric head approximately 60 nm, the phage could be assigned to the
family Siphoviridae, According to these criteria, both of the phages (A22 and L5)
belong to the order Caudovirales (tailed bacteriophages). Based on PCR amplification
of A22 phage DNA using L5 gp71 specific primers and the infection of M. smegmatis
L5 lysogen, we believe that this novel A22 phage differs from L5 phage.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:wits/oai:wiredspace.wits.ac.za:10539/7379 |
| Date | 21 October 2009 |
| Creators | Lukusa, Kambulu |
| Source Sets | South African National ETD Portal |
| Language | English |
| Detected Language | English |
| Type | Thesis |
| Format | application/pdf, application/pdf, application/pdf |
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