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"In silico"


From Wikipedia
If the target host* of a phage therapy treatment is not an animal the term "biocontrol" (as in phage-mediated biocontrol of bacteria) is usually employed, rather than "phage therapy".

In silico
From:"Genomics,Proteomics and Clinical Bacteriology",N.Woodford and Alan P.Johnson

Phrase that emphasizes the fact that many molecular biologists spend increasing amounts of their time in front of a computer screen, generating hypotheses that can subsequently be tested and (hopefully) confirmed in the laboratory.


Phage Therapy is influenced by:

Phage therapy is influenced by:

Country : the epidemiological situation is different from country to country in terms of circulating bacteria and bacteriophages. Example: lytic phages from Italy may be no active on the same bacteria (genus and species) isolated from another country and vice versa.
Temporariness
Mutation rate
Phenotypical delay
Phage cocktail

My point of view

Monday, 16 August 2010

My remarks about Mycobacterium ulcerans genome

Most probably the idea to utilize Phage Therapy in Buruli disease is impracticable.

In the Net there is not any information about this.

In spite of everything I think it is useful to try all possibilities for exploring new forms of drugs
in Buruli disease and among these also Phage therapy.

I quote the passages from :

Reductive evolution and niche adaptation inferred from the genome
of Mycobacterium ulcerans, the causative agent of Buruli ulcer



".....771 pseudogenes, two bacteriophages, and multiple DNA deletions and rearrangements."

"The two prophages named phiMU01 (18 kb, 18 CDS) and phiMU02 (24 kb, 17 CDS) resemble other mycobacteriophages in overall structure, integrating near tRNA genes and containing CDS associated with replication functions. However, phiMU02 may be non-functional, as several of its genes have been inactivated by multiple IS2606 insertions."

"...and acquisition of foreign genes, often via plasmids or bacteriophage, that confer a fitness advantage in the new environment."

I want to check the passages quoted above because they are not described in details:

1° passage:

"The two prophages named phiMU01 (18 kb, 18 CDS) and phiMU02 (24 kb, 17 CDS) resemble other mycobacteriophages in overall structure, integrating near tRNA genes and containing CDS associated with replication functions."

In the beginning if these prophages were mycobacterium phages probably they have still some common features with other Mycobacterium phage genomes like D29,L5, BXZ2 and TM4.

2° passage:

"...phiMU02 may be non-functional, as several of its genes have been inactivated by multiple IS2606 insertions."


Now to shoot off :

a-
For avoiding misunderstandings I have written the words by WIKIPEDIA:

Prophage:

A prophage is a phage genome inserted as part of the linear structure of the DNA chromosome of a bacterium. A temperate phage integrated into the host chromosome or existing as an extrachromosomal plasmid. This is a latent form of a bacteriophage in which the viral genes are incorporated into the bacterial chromosomes without causing disruption of the bacterial cell.

Upon detection of host cell damage, the prophage is excised from the bacterial chromosome in a process called prophage induction. After induction, viral replication begins via the lytic cycle. Prophages are important agents of horizontal gene transfer, and are considered to be part of the mobilome.


Bacteriophage

b-
phiMU01 and phiMU02 sequences are extracted from Mycobacterium ulcerans genome by Artemis software :

>misc_feature misc_feature Prophage phiMU01 523696:542119 forward
CCTTGCCGATAGACGGTACCGGCGCGCCCTGACGGGA
CGCGAACGATCAAGAAGCTACCCGCGCCGGTGTCGCT
GGACGGCACTCTAATAACGTCGCGGCTCGCTGGCGTT
GGAATTCAG..........AATC

>misc_feature misc_feature Prophage phiMU02 3582899:3606951 reverse
GTCAAGTGGTCGCAGGTTCAAATCCTGTCAGCCCGACCA
GAACGTTCTTACTCAAACCAGTGACCGAAAAGACACCGG
CCAAGGTGAGCGACTCCGTTCCGGTGGATCTAGGAGCC
CCTG......ACAT

c- each prophage genome
is examined and compared with D29, L5,TM4 and BXZ2 genomes by Gepard software:


phiMU01
and phiMU02:




phiMU01
and phiMU01:



phiMU02
and phiMU02:









phiMU01
and D29 phage :





d-
by Mauve software and M-GCAT sofware the genomes are compared:


with two
phiMU01 and phiMU02 prophages:






with
phiMU01, phiMU02 and D29 phage:




The LCB weight sets the minimum number of matching nucleotides identified in a collinear region for that region to be considered true homology versus random similarity.


with phiMU01, phiMU02 and BXZ2 phage:





with phiMU01, phiMU02 and L5 phage:





with phiMU01, phiMU02 and TM4 phage:





with all phages above:






e-Conclusions :



phiMU01 and D29 phage



with all phages above:





This analysis reinforces my conviction about the presence in the soil , fresch water or in other sources of specific phages for Mycobacterium ulcerans. I am sure "nothing seek, nothing find".