Urban, M. D. | bioRxiv Science

bioRxiv2019

A primer genetic toolkit for exploring mitochondrial biology and disease using zebrafish

Mitochondria are a dynamic eukaryotic innovation that play diverse roles in biology and disease. The mitochondrial genome is remarkably conserved in all vertebrates, encoding the same 37 gene set and overall genomic structure ranging from 16,596 base pairs (bp) in the teleost zebrafish (Danio rerio) to 16,569 bp in humans. Mitochondrial disorders are amongst the most prevalent inherited diseases affecting roughly 1 in every 5000 individuals. Currently, few effective treatments exist for those with mitochondrial ailments, representing a major unmet patient need. Mitochondrial dysfunction is also implicated to be a common component of a wide variety of other human illnesses ranging from neurodegenerative disorders like Huntingtons disease and Parkinsons disease to autoimmune illnesses such as multiple sclerosis and rheumatoid arthritis. The electron transport chain (ETC) component of mitochondria is critical for mitochondrial biology and defects can lead to many mitochondrial disease symptoms. Here we present a publicly available collection of genetic mutants created in highly conserved, nuclear-encoded mitochondrial genes in Danio rerio. The zebrafish system represents a potentially powerful new opportunity for the study of mitochondrial biology and disease due to the large number of orthologous genes shared with humans and the many advanced features of this model system from genetics to imaging. This collection includes 22 mutant lines in 18 different genes created by locus-specific gene editing to induce frameshift or splice acceptor mutations leading to predicted protein truncation during translation. Also included are 6 lines created by the random insertion of the gene-breaking transposon (GBT) protein trap cassette. All of these targeted mutant alleles truncate conserved domains of genes critical to the proper function of the ETC or genes that have been implicated in human mitochondrial disease. This collection is designed to accelerate the use of zebrafish to study of many different aspects of mitochondrial function with the goal of widening our understanding of their role in biology and human disease.

molecular biology↗

bioRxiv2018

Humidity as a non-pharmaceutical intervention for influenza A

Influenza is a global problem infecting 5-10 % of adults and 20-30 % of children annually. Non-pharmaceutical interventions (NPIs) are attractive approaches to complement vaccination in the prevention and reduction of influenza. Strong cyclical reduction of absolute humidity has been associated with influenza outbreaks in temperate climates. This study tested the hypothesis that raising absolute humidity above seasonal lows would impact influenza virus survival and transmission in a key source of influenza distribution, a community school. Air samples and objects handled by students (e.g. blocks and markers) were collected from preschool classrooms. All samples were processed and PCR used to determine the presence of influenza and its amount. Additionally samples were tested for their ability to infect cells in cultures. Deliberate classroom humidification (with commercial steam humidifiers) resulted in a significant reduction of the total number of influenza positive samples (air and fomite), viral copy number, and efficiency of viral infectivity. This is the first prospective study suggesting that exogenous humidification could serve as a scalable NPI for influenza or other viral outbreaks.\n\nAuthor summaryHuman influenza infections have a substantial impact on society (including lost productivity and medical costs). Children, 3-4 years of age are the main introducers and spreaders of influenza within a household and community. There is evidence from laboratory and epidemiological studies that suggests that low humidity in winter (in temperate climates) may increase the ability of influenza virus to survive and spread between individuals. We wanted to know if added in humidity (through steam humidifiers) could reduce the amount of influenza present and its spread within preschool classrooms (students aged 3-4 years)? Additionally, we looked at the infectivity of the influenza isolated and if there were differences in the number of students with influenza-like illnesses during our study. We show that humidification can reduce the amount of influenza present within samples from preschool classrooms and that there were fewer infectious samples compared to non-humidified rooms. There were small numbers of students ill with influenza like illnesses during our study so additional studies will need to look further at humidification as a way to reduce influenza infection and transmission.

microbiology↗