Biology subjects

Gill, A.

Publications and source records attributed to Gill, A..

20 records · Page 2Linked to original sources

bioRxiv2019

Evaluation of High-Pressure Processing in Inactivation of the Hepatitis E Virus

Hepatitis E virus (HEV) causes acute hepatitis with approximately 20 million cases per year globally. While HEV is endemic in certain regions of Asia, Africa and South America, it is considered an emerging foodborne pathogen in developed countries. Based on genetic diversity, HEV is classified into different genotypes, with genotype 3 (HEV-3) being most prevalent in Europe and North America. The transmission of HEV-3 has been shown to be zoonotic and mainly associated with the consumption of raw or undercooked pork products. Herein, we investigated the efficacy of high-pressure processing (HPP) in the inactivation of HEV-3 using a cell culture system. HPP has been indicated as a promising nonthermal pathogen inactivation strategy for treatment of certain high-risk food commodities, without any noticeable changes in their nature. For this purpose, we treated HEV-3 in media as well as in artificially inoculated pork pate, with different conditions of HPP: 400 MPa for 1 and 5 minutes, as well as 600 MPa for 1 and 5 minutes, at ambient temperature. In general, we observed approximately a 2-log reduction in HEV load by HPP treatments in media; however, similar treatment in the pork pate resulted in a much lower reduction in viral load. Therefore, the efficacy of HPP treatment in the inactivation of HEV-3 is matrix-dependent.\n\nImportanceHEV is an emerging foodborne pathogen in industrialized countries, and its transmission is associated with the consumption of contaminated undercooked pork product. In this work, we employed an infectivity assay to investigate the potential of high-pressure in inactivation of HEV in media and ready-to-eat pork pate. We demonstrated that the effect of HPP on inactivation of HEV depends on the surrounding matrix.

microbiology↗

bioRxiv2018

Intensive and Specific Feedback Self-control of MicroRNA Targeting Activity

The miRNA pathway consists of three segments - biogenesis, targeting and downstream regulatory effectors. How the cells control their activities remains incompletely understood. This study explored the intrinsically complex miRNA-mRNA targeting relationships, and suggested differential mechanistic control of the three segments. We first analyzed evolutionarily conserved sites for conserved miRNAs in the human transcriptome. Strikingly, AGO1, AGO2 and AGO3 are all among the top 14 mRNAs with highest numbers of unique conserved miRNA sites, and so is ANKRD52, the phosphatase regulatory subunit of the recently identified AGO phosphorylation cycle (AGOs, CSNK1A1, ANKRD52 and PPP6C). The mRNAs for TNRC6, which acts together with loaded AGO to channel miRNA-mediated regulation actions onto specific mRNAs, are also heavily miRNA-targeted. Moreover, mRNAs of the AGO phosphorylation cycle share much more than expected miRNA binding sites. In contrast, upstream miRNA biogenesis mRNAs do not display these characteristics, and neither do the downstream regulatory effector mRNAs. In a word, miRNAs heavily and directly feedback-regulate their targeting machinery mRNAs, but neither upstream biogenesis nor downstream regulatory effector mRNAs. The observation was then confirmed with experimentally determined miRNA-mRNA target relationships. In summary, our exploration of the miRNA-mRNA target relationship uncovers intensive, and specific, feedback auto-regulation of miRNA targeting activity directly by miRNAs themselves, i.e., segment-specific feedback auto-regulation of miRNA pathway. Our results also suggest that the complexity of miRNA-mRNA targeting relationship - a defining feature of miRNA biology - should be a rich source for further functional exploration.

cell biology↗