Photo inactivation of virus particles in microfluidic capillary systems.

It has long been established that UVC light is a very effective method for inactivating pathogens in a fluid, yet the application of UVC irradiation to modern biotechnological processes is limited by the intrinsic short penetration distance of UVC light in optically dense protein solutions. This experimental and numerical study establishes that irradiating a fluid flowing continuously in a microfluidic capillary system, in which the diameter of the capillary is tuned to the depth of penetration of UVC light, uniquely treats the whole volume of the fluid to UVC light, resulting in fast and effective inactivation of pathogens, with particular focus to virus particles. This was demonstrated by inactivating human herpes simplex virus type-1 (HSV-1, a large enveloped virus) on a dense 10% fetal calf serum solution in a range of fluoropolymer capillary systems, including a 0.75 mm and 1.50 mm internal diameter capillaries and a high-throughput MicroCapillary Film with mean hydraulic diameter of 206 μm. Up to 99.96% of HSV-1 virus particles were effectively inactivated with a mean exposure time of up to 10 s, with undetectable collateral damage to solution proteins. The kinetics of virus inactivation matched well the results from a new mathematical model that considers the parabolic flow profile in the capillaries, and showed the methodology is fully predictable and scalable and avoids both the side effect of UVC light to proteins and the dilution of the fluid in current tubular UVC inactivation systems. This is expected to speed up the industrial adoption of non-invasive UVC virus inactivation in clinical biotechnology and biomanufacturing of therapeutic molecules. Biotechnol. Bioeng. 2016;113: 1481-1492. © 2015 Wiley Periodicals, Inc.This is the accepted manuscript. The final version is available at http://onlinelibrary.wiley.com/wol1/doi/10.1002/bit.25912/full

Vesicular Egress of Non-Enveloped Lytic Parvoviruses Depends on Gelsolin Functioning

The autonomous parvovirus Minute Virus of Mice (MVM) induces specific changes in the cytoskeleton filaments of infected permissive cells, causing in particular the degradation of actin fibers and the generation of “actin patches.” This is attributed to a virus-induced imbalance between the polymerization factor N-WASP (Wiscott-Aldrich syndrome protein) and gelsolin, a multifunctional protein cleaving actin filaments. Here, the focus is on the involvement of gelsolin in parvovirus propagation and virus-induced actin processing. Gelsolin activity was knocked-down, and consequences thereof were determined for virus replication and egress and for actin network integrity. Though not required for virus replication or progeny particle assembly, gelsolin was found to control MVM (and related H1-PV) transport from the nucleus to the cell periphery and release into the culture medium. Gelsolin-dependent actin degradation and progeny virus release were both controlled by (NS1)/CKIIα, a recently identified complex between a cellular protein kinase and a MVM non-structural protein. Furthermore, the export of newly synthesized virions through the cytoplasm appeared to be mediated by (virus-modified) lysomal/late endosomal vesicles. By showing that MVM release, like entry, is guided by the cytoskeleton and mediated by vesicles, these results challenge the current view that egress of non-enveloped lytic viruses is a passive process

Etude biochimique, chez E. Coli d'un mécanisme de réparation inductible et mutagène

Doctorat en Sciencesinfo:eu-repo/semantics/nonPublishe

Kinetics of induction of error prone repair of bacteriophage λ by temperature shift in an Escherichia coli dnaB mutant

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

LA 2 AMINO-PURINE, UN ANALOGUE DE L'ADENINE, INDUIT CHEZ E.COLI UN MECANISME DE REPARATION NON MUTAGENE AGISSANT SUR LES LESIONS ULTRAVIOLETTES DANS L'ADN DOUBLE-BRIN

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Phage yield during W-reactivation of bacteriophage λ

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Genetic control of the UV-induced SOS mutator effect in single- and double-stranded DNA phages

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

2-Aminopurine induced DNA repair in E. coli

SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Nature of the SOS mutator activity: Genetic characterization of untargeted mutagenesis in Escherichia coli

SCOPUS: ar.jinfo:eu-repo/semantics/publishe