messaggio

clik on the image and visit the new site

New site clik on the image

"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 March 2009

Multiplicity of Infection or MOI



N= starting phage density

B= starting bacterial density

p= probability of a single phage particle for infecting a single bacterium

a= number of infecting phage particles

p=a/B

B(0)= bacterial cells not infected
B(1)= bacterial cells infected by one phage particle
B(>1)= bacterial cells infected by several phage particles

n=number of infecting phage particles


Multiplicity of Infection or MOI


m=Multiplicity of Infection or MOI

m=p*N
m= a*N/B
a*N= plaque-forming unit (PFU)
a*N=-B*lnB(0)


Poisson distribution


An estimate of Bacterial cells proportion infected by n phage particles
is:

B(n)= e^-m* m^n/n!


and an estimate of Cellular Classes inside a Bacterial population infected by phages is :

Number of phage particles =0
; B(0)=e^-m
Number of phage particles =1
; B(1)=e^-m *m
Number of phage particles >1
; B(>1)=1-e^-m*(m+1)


Example:

If m= 10 and B=10^7 bacterial cells

B(0)= e^-10= 4,5 *10 ^-5
bacterial cells not infected= 4,5*10^-5*10^7= 450 bacteria

B(1)=e^-10*10=4,5*10^-5*10
bacterial cells infected by one phage particle =4,5*10^-4*10^7=4500 bacteria

B(>1) =1-e^-10*(10+1)
bacterial cells infected by several phage particles=(1-4,5*10^-5(11))*10^7=9,995,050 bacteria