ORCID Profile
0000-0002-9973-2740
Current Organisations
Canada Research Chairs
,
Université Laval
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Publisher: Oxford University Press (OUP)
Date: 22-07-2003
DOI: 10.1093/BIOINFORMATICS/BTG169
Abstract: Summary: 2HAPI (version 2 of High density Array Pattern Interpreter) is a web-based, publicly-available analytical tool designed to aid researchers in microarray data analysis. 2HAPI includes tools for searching, manipulating, visualizing, and clustering the large sets of data generated by microarray experiments. Other features include association of genes with NCBI information and linkage to external data resources. Unique to 2HAPI is the ability to retrieve upstream sequences of co-regulated genes for promoter analysis using MEME (Multiple Expectation-maximization for Motif Elicitation) Availability: 2HAPI is freely available at array.sdsc.edu. Users can try 2HAPI anonymously with pre-loaded data or they can register as a 2HAPI user and upload their data. Contact: gribskov@sdsc.edu * To whom correspondence should be addressed.
Publisher: Springer Science and Business Media LLC
Date: 29-05-2008
Abstract: Leishmania parasites cause a erse spectrum of diseases in humans ranging from spontaneously healing skin lesions (e.g., L. major ) to life-threatening visceral diseases (e.g., L. infantum ). The high conservation in gene content and genome organization between Leishmania major and Leishmania infantum contrasts their distinct pathophysiologies, suggesting that highly regulated hierarchical and temporal changes in gene expression may be involved. We used a multispecies DNA oligonucleotide microarray to compare whole-genome expression patterns of promastigote (sandfly vector) and amastigote (mammalian macrophages) developmental stages between L. major and L. infantum . Seven per cent of the total L. infantum genome and 9.3% of the L. major genome were differentially expressed at the RNA level throughout development. The main variations were found in genes involved in metabolism, cellular organization and biogenesis, transport and genes encoding unknown function. Remarkably, this comparative global interspecies analysis demonstrated that only 10–12% of the differentially expressed genes were common to L. major and L. infantum . Differentially expressed genes are randomly distributed across chromosomes further supporting a posttranscriptional control, which is likely to involve a variety of 3'UTR elements. This study highlighted substantial differences in gene expression patterns between L. major and L. infantum . These important species-specific differences in stage-regulated gene expression may contribute to the disease tropism that distinguishes L. major from L. infantum.
Publisher: American Society for Microbiology
Date: 11-2014
DOI: 10.1128/AAC.02956-14
Abstract: The evolution of oseltamivir resistance mutations during selection through serial passages in animals is still poorly described. Herein, we assessed the evolution of neuraminidase (NA) and hemagglutinin (HA) genes of influenza A/WSN/33 (H1N1) and A/Victoria/3/75 (H3N2) viruses recovered from the lungs of experimentally infected BALB/c mice receiving suboptimal doses (0.05 and 1 mg/kg of body weight/day) of oseltamivir over two generations. The traditional phenotypic and genotypic methods as well as deep-sequencing analysis were used to characterize the potential selection of mutations and population dynamics of oseltamivir-resistant variants. No oseltamivir-resistant NA or HA changes were detected in the recovered A/WSN/33 viruses. However, we observed a positive selection of the I222T NA substitution in the recovered A/Victoria/3/75 viruses, with a frequency increasing over time and with an oseltamivir concentration from 4% in the initial pretherapy inoculum up to 28% after two lung passages. Although the presence of mixed I222T viral populations in mouse lungs only led to a minimal increase in oseltamivir 50% enzyme-inhibitory concentrations (IC 50 s) (by a mean of 5.7-fold) compared to that of the baseline virus, the expressed recombinant A/Victoria/3/75 I222T NA protein displayed a 16-fold increase in the oseltamivir IC 50 level compared to that of the recombinant wild type (WT). In conclusion, the combination of serial in vivo passages under neuraminidase inhibitor (NAI) pressure and temporal deep-sequencing analysis enabled, for the first time, the identification and selection of the oseltamivir-resistant I222T NA mutation in an influenza H3N2 virus. Additional in vivo selection experiments with other antivirals and drug combinations might provide important information on the evolution of antiviral resistance in influenza viruses.
Publisher: Springer Science and Business Media LLC
Date: 1995
DOI: 10.3109/13550289509111026
Abstract: We sought to determine whether the neurotoxin quinolinic acid (QUIN) was produced by macrophages or lymphocytes infected with isolates of HIV-1 with varying degrees of macrophage tropism derived from patients with varying stages of AIDS dementia complex (ADC). Highly macrophage tropic isolates and minimally macrophage tropic isolates were used to inoculate macrophages and QUIN production was measured. Similarly, QUIN production from macrophages was monitored using a purified cell free highly macrophage tropic isolate and laboratory isolates SF33 and SF2. Each of these experiments was also performed with lymphocytes. We found that macrophages infected with macrophage tropic isolates of HIV-1 led to QUIN production while lymphocytes did not produce QUIN. The ability of the HIV-1 infected macrophages to produce QUIN was related to the viral inoculum and the degree of macrophage tropism of the isolate. The severity of ADC in the patient from whom a particular isolate was derived was not per se a determining factor for QUIN production. Purified cell free ADC isolates also led to QUIN production by macrophages thereby suggesting that HIV-1 infection alone is capable of inducing QUIN production.
Publisher: American Society for Microbiology
Date: 12-10-2017
Abstract: The Romboutsia maritimum sp. nov. CCRI-22766 T strain was isolated from coastal estuarine mud in New Zealand. The genome assembly comprised 2,854,352 bp, with 27.1% G+C content. This is the first documentation that reports the genome sequence of R. maritimum .
Publisher: American Society for Microbiology
Date: 04-2013
DOI: 10.1128/JVI.02497-12
Abstract: T follicular helper (Tfh) cells are a specialized subset of memory CD4 + T cells that are found exclusively within the germinal centers of secondary lymphoid tissues and are important for adaptive antibody responses and B cell memory. Tfh cells do not express CCR5, the primary entry coreceptor for both human immunodeficiency virus type 1 (HIV-1) and simian immunodeficiency virus (SIV), and therefore, we hypothesized that these cells would avoid infection. We studied lymph nodes and spleens from pigtail macaques infected with pathogenic strain SIVmac239 or SIVmac251, to investigate the susceptibility of Tfh cells to SIV infection. Pigtail macaque PD-1 high CD127 low memory CD4 + T cells have a phenotype comparable to that of human Tfh cells, expressing high levels of CXCR5, interleukin-21 (IL-21), Bcl-6, and inducible T cell costimulator (ICOS). As judged by either proviral DNA or cell-associated viral RNA measurements, macaque Tfh cells were infected with SIV at levels comparable to those in other CD4 + memory T cells. Infection of macaque Tfh cells was evident within weeks of inoculation, yet we confirmed that Tfh cells do not express CCR5 or either of the well-known alternative SIV coreceptors, CXCR6 and GPR15. Mutations in the SIV envelope gp120 region occurred in chronically infected macaques but were uniform across each T cell subset investigated, indicating that the viruses used the same coreceptors to enter different cell subsets. Early infection of Tfh cells represents an unexpected focus of viral infection. Infection of Tfh cells does not interrupt antibody production but may be a factor that limits the quality of antibody responses and has implications for assessing the size of the viral reservoir.
No related grants have been discovered for Jacques Corbeil.