2 results about "Mutant strain" patented technology

The present invention relates to a safe non-virulent Yersinia enterocolitica mutant strain for delivering heterologous proteins in target cells carrying mutations in at least one of the effector genes yopH, yopO, yopP, yopE, yopM, yopT genes and at least one additional mutation in the invasin genes chosen from yadA and/or inv. The present invention also relates to a safe non-virulent Yersinia enterocolitica mutant strain for delivering heterologous proteins in target cells according to claim 1 carrying mutations in all effector genes yopH, yopO, yopP, yopE, yopM, yopT genes and at least one additional mutation in the invasin genes chosen from yadA and/or inv. The present invention also relates to an expression vector for delivering a heterologous protein into a target cell using a Yersinia enterocolitica mutant strain according to any of the claims 1 to 4, which comprises in the 5' to 3' direction :(a) a promoter of a Yersinia virulon gene, (b) a first DNA sequence encoding a delivery signal from a Yersinia effector protein, operably linked to said promoter; and, (c) a second DNA sequence coding for said heterologous protein, fused in frame to the 3' end of said first DNA sequence. The present invention further relates to methods and compositions comprising (the use of) the afore-mentioned mutant strains and expression vectors.

A method for the accurate quantification of a virus in a sample, by reverse transcription polymerase chain reaction (RT-PCR), includes: adding a known concentration of a Mengo virus to the sample as control for the nucleic acids extraction step, the Mengo virus being a mutant strain with the same growth properties than those of the wild-type Mengo virus, and with non-pathogenic capacity; performing a nucleic acids extraction to obtain a nucleic acids suspension; analyzing the nucleic acids suspension by RT-PCR with primers and probes; quantifying the amplimers resulting from the RT-PCR; determining the concentration of the virus in the sample by comparison of the value obtained with an appropriate standard curve; and determining the concentration of the Mengo virus by comparison of the value obtained with an appropriate standard curve.