No abstract

The ref(2)P gene of Drosophila melanogaster interferes with sigma rhabdovirus multiplication. This gene is highly variable, and the different alleles are considered permissive or restrictive according to their effects on virus replication. In all cases, the mechanisms involve intracellular interactions between the sigma virus and Ref(2)P proteins. We showed that the N-terminal domain of the Ref(2)P protein was required for its activity in vivo. The protein was inactive in the null p od2 mutant when its first 82 amino acids were deleted. The p ⌬n gene was constructed so that the first 91 amino acids coded for by the restrictive alleles could be expressed in vivo. It was active in a transformed line. This sequence was sufficient to impart a restrictive phenotype to an adult D. melanogaster fly after it was injected with the virus. However, the truncated protein expressed by p ⌬n did not have an effect on the hereditary transmission of the sigma virus to the offspring of the infected flies, even though it contained the restriction site. The native Ref(2)P protein has been previously shown to have conformation-dependent epitopes common with some of those of the viral N protein. We demonstrated the following. (i) These epitopes were found in a domain of the Ref(2)P protein distinct from the site involved in restriction. (ii) They were modified in the N protein of the haP7 sigma virus mutant selected as being adapted to the restrictive alleles of the ref(2)P gene; only one mutation in the N gene, leading to an amino acid substitution, distinguished the haP7 mutant from the original virus. (iii) The virus strains partially or totally adapted to the effects of the full restrictive protein expressed by p p were always found to multiply to a lesser extent in the presence of the protein expressed by p ⌬n. These data suggest that two distinct domains of the Ref(2)P protein are involved in the control of sigma virus multiplication.

The ref(2)P gene is a Drosophila gene which acts on Sigma virus multiplication. From recombination experiments the ref(2)P gene was located between hk and pr. This location was confirmed by the study of eight chromosomic aberrations, without ref(2)P gene activity, obtained following X irradiation. From the cytological study of three of these chromosomes and from the study of the ref(2)P gene activity of chromosomic aberrations obtained by other workers in the same region of the second chromosome, the ref(2)P gene was cytologically located in 37E3-37F3.

GPU usage has become mandatory for the processing of (3D) medical data, as well as for efficient machine learning approaches such as deep learning. In this contribution, we present how VIP and DIRAC can be leveraged to run medical image processing applications on distributed computing resources equipped with GPUs. VIP (Virtual Imaging Platform) is a web portal for the simulation and processing of massive data in medical imaging. VIP users can access applications as a service and significant amounts of computing resources and storage with no required technical skills beyond the use of a web browser. VIP relies on the DIRAC (Distributed Infrastructure with Remote Agent Control) interware for scheduling tasks for execution on distributed infrastructures such as grid, clouds, and local clusters. New applications are regularly integrated into VIP/DIRAC. They all have their own requirements, among which GPU usage is more and more frequent. This contribution will give an overview of the targeted medical applications and their requirements, as well as technical insights on how VIP and DIRAC allow end users to efficiently exploit GPU resources with no specific knowledge about the underlying distributed infrastructure.