Enterohemorrhagic Escherichia coli O157∶H7 Gene Expression Profiling in Response to Growth in the Presence of Host Epithelia

BACKGROUND: The pathogenesis of enterohemorrhagic Escherichia coli (EHEC) O157:H7 infection is attributed to virulence factors encoded on multiple pathogenicity islands. Previous studies have shown that EHEC O157:H7 modulates host cell signal transduction cascades, independent of toxins and rearrangement of the cytoskeleton. However, the virulence factors and mechanisms responsible for EHEC-mediated subversion of signal transduction remain to be determined. Therefore, the purpose of this study was to first identify differentially regulated genes in response to EHEC O157:H7 grown in the presence of epithelial cells, compared to growth in the absence of epithelial cells (that is, growth in minimal essential tissue culture medium alone, minimal essential tissue culture medium in the presence of 5% CO(2), and Penassay broth alone) and, second, to identify EHEC virulence factors responsible for pathogen modulation of host cell signal transduction. METHODOLOGY/PRINCIPAL FINDINGS: Overnight cultures of EHEC O157:H7 were incubated for 6 hr at 37 degrees C in the presence or absence of confluent epithelial (HEp-2) cells. Total RNA was then extracted and used for microarray analyses (Affymetrix E. coli Genome 2.0 gene chips). Relative to bacteria grown in each of the other conditions, EHEC O157:H7 cultured in the presence of cultured epithelial cells displayed a distinct gene-expression profile. A 2.0-fold increase in the expression of 71 genes and a 2.0-fold decrease in expression of 60 other genes were identified in EHEC O157:H7 grown in the presence of epithelial cells, compared to bacteria grown in media alone. CONCLUSION/SIGNIFICANCE: Microarray analyses and gene deletion identified a protease on O-island 50, gene Z1787, as a potential virulence factor responsible for mediating EHEC inhibition of the interferon (IFN)-gamma-Jak1,2-STAT-1 signal transduction cascade. Up-regulated genes provide novel targets for use in developing strategies to interrupt the infectious process

Gene therapy for primary immune deficiencies: a Canadian perspective

The use of gene therapy (GT) for the treatment of primary immune deficiencies (PID) including severe combined immune deficiency (SCID) has progressed significantly in the recent years. In particular, long-term studies have shown that adenosine deaminase (ADA) gene delivery into ADA-deficient hematopoietic stem cells that are then transplanted into the patients corrects the abnormal function of the ADA enzyme, which leads to immune reconstitution. In contrast, the outcome was disappointing for patients with X-linked SCID, Wiskott–Aldrich syndrome and chronic granulomatous disease who received GT followed by autologous gene corrected transplantations, as many developed hematological malignancies. The malignancies were attributed to the predilection of the viruses used for gene delivery to integrated at oncogenic areas. The availability of safer and more efficient self-inactivating lentiviruses for gene delivery has reignited the interest in GT for many PID that are now in various stages of pre-clinical studies and clinical trials. Moreover, advances in early diagnosis of PID and gene editing technology coupled with enhanced abilities to generate and manipulate stem cells ex vivo are expected to further contribute to the benefit of GT for PID. Here we review the past, the present and the future of GT for PID, with particular emphasis on the Canadian perspective

Effect of Vermicomposting and Composting of Municipal Solid Waste (MSW) on Growth, Yield and Quality of Chickpea

The present investigation was undertaken with an objective to understand the effect of municipal solid waste (MSW) vermicompost and compost on growth, yield and quality of chickpea. The experiment was laid in randomized block design with three replications and seven treatments  viz, T1 - RDF, T2 - RDF + vermicompost of MSW @ 2.5 t ha-1, T3 - RDF + vermicompost of MSW @ 5 t ha-1, T4 - RDF + vermicompost of MSW @ 7.5 t ha-1, T5 - RDF + compost of MSW @ 2.5 t ha-1, T6 -compost of MSW @ 5 t ha-1, T7 -compost of MSW @ 7.5 t ha-1. The field experiment was conducted at College of Agriculture, Latur farm during the Rabi season 2016-2017. The recommended dose of fertilizer (25:50:00 N: P: K) and MSW vermicompost and compost was applied at the time of sowing. The results of field experiment revealed that the maximum availability of macro and micronutrients in soil, growth attributes viz. plant height and number of branches in all growth stages of chickpea were found at application of 7.5 tones of MSW vermicompost ha-1 along with 100% RDF (25:50:00 NPK) followed by application of 7.5 tones MSW compost ha-1 along with 100% RDF and which was significantly increased with increased levels of MSW vermicompost and compost. Similar trend was observed in case of yield and quality parameters viz., protein content of chickpea

Identification of a Feline Leukemia Virus Variant That Can Use THTR1, FLVCR1, and FLVCR2 for Infection▿

The pathogenic subgroup C feline leukemia virus (FeLV-C) arises in infected cats as a result of mutations in the envelope (Env) of the subgroup A FeLV (FeLV-A). To better understand emergence of FeLV-C and potential FeLV intermediates that may arise, we characterized FeLV Env sequences from the primary FY981 FeLV isolate previously derived from an anemic cat. Here, we report the characterization of the novel FY981 FeLV Env that is highly related to FeLV-A Env but whose variable region A (VRA) receptor recognition sequence partially resembles the VRA sequence from the prototypical FeLV-C/Sarma Env. Pseudotype viruses bearing FY981 Env were capable of infecting feline, human, and guinea pig cells, suggestive of a subgroup C phenotype, but also infected porcine ST-IOWA cells that are normally resistant to FeLV-C and to FeLV-A. Analysis of the host receptor used by FY981 suggests that FY981 can use both the FeLV-C receptor FLVCR1 and the feline FeLV-A receptor THTR1 for infection. However, our results suggest that FY981 infection of ST-IOWA cells is not mediated by the porcine homologue of FLVCR1 and THTR1 but by an alternative receptor, which we have now identified as the FLVCR1-related protein FLVCR2. Together, our results suggest that FY981 FeLV uses FLVCR1, FLVCR2, and THTR1 as receptors. Our findings suggest the possibility that pathogenic FeLV-C arises in FeLV-infected cats through intermediates that are multitropic in their receptor use

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Not AvailableBiofortification is a cost-effective and sustainable diet-based intervention to alleviate the foodrelated health problem of micronutrient malnourishment. Sorghum is a crop of sub-tropical and semi-arid regions of Africa and Asia where it is staple food for more than 500 million poor and most nutrition-insecure people. Breeding sorghum with more grain iron (Fe) and zinc (Zn), and regular consumption of such biofortified grains can improve the health status of predominantly sorghum eating populations. The availability of genetic variability for grain micronutrients is necessary for genetic manipulation. In order to assess the variability for grain micronutrients and identify suitable donors for breeding programme more than 400 sorghum genotypes comprising cultivars, hybrid parents, breeding lines and selected germplasm accessions were characterized for grain Fe and Zn. Good variation was observed for both micronutrients among the genotypes. The mean grain Fe ranged from 26.9 ppm (cultivars) to 37.6 ppm (exotic germplasm) while mean grain Zn ranged from 22.9 ppm (breeding lines) to 34.0 ppm (exotic germplasm). The exotic lines (n=39) comprising some accessions from sorghum mini-core collection showed a wide variation for grain Fe (25.7-62.2 ppm) while indigenous germplasm including landraces (n=260) had a wide range for Zn (9.4-43.7 ppm). A relatively narrow range was observed in cultivars (18.2-41.3 ppm Fe, 16.6-35.4 ppm Zn; n=61), parentals (18.0-38.5 ppm Fe, 18.0-37.5 ppm Zn; n=25) and breeding lines (19.1-40.0 ppm Fe, 15.4- 34.0 ppm Zn; n=25). The results indicate that suitable donors for Fe and Zn improvement can be identified from germplasm though it may be limited under improved agronomic backgrounds. The presence of good variability for grain micronutrients holds promise for recombination breeding to combine nutritional quality and high grain yield. The significant correlation (r=0.33-0.73) between Fe and Zn content indicates the possibility of simultaneous improvement. Based on the spectrum of variability identified an association mapping panel was constituted for GWAS for grain micronutrients.Not Availabl

Dynamics of free-surface mutually perpendicular twin liquid sheets and their atomization characteristics

International audienceThe radially expanding twin (circular and vertical) liquid sheets produced by impingement of a vertical cylindrical liquid jet onto a horizontally placed cone-disk deflector with a single slot were examined experimentally in the present work. Dynamics of these liquid sheets and the events leading to their breakup were studied by carrying out high-speed shadowgraphy simultaneously from side, front, and top views at a 5.4 kHz framing rate and for the jet Weber number (Wejet) range of 993 < Wejet < 3776. In the presence of the slot, the variation of the radial breakup distance of the circular sheet (Rb,CS) with Wejet changed from the monotonically decreasing trend (Rb,CS∼Wejet−0.44) to a nonmonotonic increasing and decreasing one. Furthermore, Rb,CS was found to be lowered by about 42% compared to the breakup distance Rb,CS,no-slot of the circular sheet for the no-slot deflector. The vertical sheet breakup distance (Rb,Vs) was found to increase monotonically with the slot Weber number Weslot0.44. Three primary sources of droplet production, namely, the lower and front edges of the vertical sheet and the rim of the circular sheet, were identified. The smallest droplets were seen to originate from the front edge (D32,FE) and the largest droplets from the lower edge (D32,LE) of the vertical sheet. The measured droplet diameters followed D32,LE∼Wejet−1/3 and D32,FE∼Wejet−1/4, whereas the droplets originating at the rim of the circular sheet followed D32,rim∼Wejet−2/3. The droplets at all three edges were found to depend more strongly on the ligament thickness than the ligament length. Following conservation of mass, a linear relation between the droplet diameter, D32, and the ligament thickness, tlig, at each edge has been obtained

The Fowler Syndrome-Associated Protein FLVCR2 Is an Importer of Heme ▿

Mutations in FLVCR2, a cell surface protein related by homology and membrane topology to the heme exporter/retroviral receptor FLVCR1, have recently been associated with Fowler syndrome, a vascular disorder of the brain. We previously identified FLVCR2 to function as a receptor for FY981 feline leukemia virus (FeLV). However, the cellular function of FLVCR2 remains unresolved. Here, we report the cellular function of FLVCR2 as an importer of heme, based on the following observations. First, FLVCR2 binds to hemin-conjugated agarose, and binding is competed by free hemin. Second, mammalian cells and Xenopus laevis oocytes expressing FLVCR2 display enhanced heme uptake. Third, heme import is reduced after the expression of FLVCR2-specific small interfering RNA (siRNA) or after the binding of the FY981 FeLV envelope protein to the FLVCR2 receptor. Finally, cells overexpressing FLVCR2 are more sensitive to heme toxicity, a finding most likely attributable to enhanced heme uptake. Tissue expression analysis indicates that FLVCR2 is expressed in a broad range of human tissues, including liver, placenta, brain, and kidney. The identification of a cellular function for FLVCR2 will have important implications in elucidating the pathogenic mechanisms of Fowler syndrome and of phenotypically associated disorders