Biology subjects

Young, G.

Publications and source records attributed to Young, G..

21 records · Page 2Linked to original sources

bioRxiv2019

A report on the detection and management of a finding of PSTVd (Potato Spindle Tuber Viroid) in potato breeding material in Northern Ireland, UK.

Potato Spindle Tuber Viroid (PSTVd) is an infectious unencapsidated, small, circular, single-stranded RNA, that causes serious losses in infected potato plants. The pathogen has been detected in several European countries, including in England in the UK. In August 2016, the National Plant Protection Organisation of the Netherlands reported a finding of PSTVd in breeding material that originated in Northern Ireland, UK. A scheme of testing was carried out in Northern Ireland to identify the source of the infected breeding material. Trace-forward and trace-back tests identified 21 infected samples, of which 16 were from true seed samples, out of a total of 591 tested up to November 2016. The number of positive findings in true seed was further reduced to 4 after the samples were surface sterilized. Tests indicated that the infection probably entered the breeding station in Northern Ireland in the mid 1980s, with limited spread in the collection via contaminated breeding equipment. The instance of spread in the field could not be ruled out. Eradication efforts included removal and destruction of infected field stocks and neighbouring stocks, destruction of stored museum material by deep burial, and destruction of other field material by ploughing and exposing tubers to frost. The risk of potato genitor material for spreading PSTVd is discussed. The situation of PSTVd in Northern Ireland, UK is Transient, actionable, under eradication.

plant biology↗

bioRxiv2019

Primary infection with dengue or Zika virus does not affect the severity of heterologous secondary infection in macaques.

Zika virus (ZIKV) and dengue virus (DENV) are genetically and antigenically related flaviviruses that now co-circulate in much of the tropical and subtropical world. The rapid emergence of ZIKV in the Americas in 2015 and 2016, and its recent associations with Guillain-Barre syndrome, birth defects, and fetal loss have led to the hypothesis that DENV infection induces cross-reactive antibodies that influence the severity of secondary ZIKV infections. It has also been proposed that pre-existing ZIKV immunity could affect DENV pathogenesis. We examined outcomes of secondary ZIKV infections in three rhesus and fifteen cynomolgus macaques, as well as secondary DENV-2 infections in three additional rhesus macaques up to a year post-primary ZIKV infection. Although cross-binding antibodies were detected prior to secondary infection for all animals and cross-neutralizing antibodies were detected for some animals, previous DENV or ZIKV infection had no apparent effect on the clinical course of heterotypic secondary infections in these animals. All animals had asymptomatic infections and, when compared to controls, did not have significantly perturbed hematological parameters. Rhesus macaques infected with DENV-2 approximately one year after primary ZIKV infection had higher vRNA loads in plasma when compared with serum vRNA loads from ZIKV-naive animals infected with DENV-2, but a differential effect of sample type could not be ruled out. In cynomolgus macaques, the serotype of primary DENV infection did not affect the outcome of secondary ZIKV infection.\n\nAuthor summaryPre-existing immunity to one of the four DENV serotypes is known to increase the risk of severe disease upon secondary infection with a different serotype. Due to the antigenic similarities between ZIKV and DENV, it has been proposed that these viruses could interact in a similar fashion. Data from in vitro experiments and murine models suggests that pre-existing immunity to one virus could either enhance or protect against infection with the other. These somewhat contradictory findings highlight the need for immune competent animal models for understanding the role of cross-reactive antibodies in flavivirus pathogenesis. We examined secondary ZIKV or DENV infections in rhesus and cynomolgus macaques that had previously been infected with the other virus. We assessed the outcomes of secondary ZIKV or DENV infections by quantifying vRNA loads, clinical and laboratory parameters, body temperature, and weight for each cohort of animals and compared them with control animals. These comparisons demonstrated that within a year of primary infection, secondary infections with either ZIKV or DENV were similar to primary infections and were not associated with enhancement or reduction in severity of disease based on the outcomes that we assessed.

pathology↗

bioRxiv2017

Quantitative mass imaging of single molecules in solution

The cellular processes underpinning life are orchestrated by proteins and their interactions. Structural and dynamic heterogeneity, despite being key to protein and drug function, continues to pose a fundamental challenge to existing analytical and structural methodologies used to study these associations. Here, we use interferometric scattering microscopy to mass-image single biomolecules in solution with <2% mass error, up to 19-kDa resolution and 1-kDa precision. Thereby, we resolve oligomeric distributions at high dynamic range, detect small-molecule binding, and mass-image biomolecules composed not only of amino acids, but also heterogeneous species, such as lipo- and glycoproteins. These capabilities enable us to characterize the molecular mechanisms of processes as diverse as oligomeric selfassembly, glycoprotein cross-linking, amyloidogenic protein aggregation, and actin polymerization. Interferometric scattering mass spectrometry (iSCAMS) provides spatially resolved access to the dynamics of biomolecular interactions ranging from those involving small molecules to mesoscopic assemblies, one molecule at a time.

biophysics↗