Biology subjects

Withers, A.

Publications and source records attributed to Withers, A..

3 recordsLinked to original sources

bioRxiv2023

Lack of detection of SARS-CoV-2 in British wildlife 2020-21 and first description of a stoat (Mustela erminea) Minacovirus

2.Repeat spillover of SARS-CoV-2 into new hosts has highlighted the critical role of cross species transmission of coronaviruses and establishment of new reservoirs of virus in pandemic and epizootic spread of coronaviruses. Species particularly susceptible to SARS-CoV-2 spill-over include Mustelidae (mink, ferrets and related animals), cricetid rodents (hamsters and related animals), felids domestic cats and related animals) and white tailed deer. These predispositions led us to screen British wildlife with sarbecovirus specific qPCR and pan coronavirus PCR assays for SARS-CoV-2 using samples collected during the human pandemic to establish if widespread spill-over was occurring. Fourteen wildlife species (n=402) were tested, including : 2 Red Foxes (Vulpes vulpes), 101 Badgers (Meles meles), 2 wild American Mink (Neogale vison), 41 Pine Marten (Martes martes), 2 Weasels (Mustela nivalis), 7 Stoats (Mustela erminea), 108 Water Voles (Arvicola amphibius), 39 Bank voles (Myodes glareolous), 10 Field Voles (Microtus agrestis), 15 Wood Mice (Apodemus sylvaticus), 1 Common Shrew (Sorex aranaeus), 2 Pygmy Shrews (Sorex minutus), 2 Hedgehogs (Erinaceus europaeus) and 75 Eurasian Otters (Lutra lutra). No cases of SARS-CoV-2 were detected in any animals, however a novel minacovirus related to mink and ferret alphacoronaviruses was detected in stoats recently introduced to the Orkney Islands. This group of viruses is of interest due to pathogenicity in ferrets. The impact of this virus on the health of stoat populations remains to be established.

microbiology↗

bioRxiv2022

3D Organic Bioelectronics for Monitoring In Vitro Stem Cell Cultures

Three-dimensional in vitro stem cell models has enabled a fundamental understanding of cues that direct stem cell fate and be used to develop novel stem cell treatments. While sophisticated 3D tissues can be generated, technology that can accurately monitor these complex models in a high-throughput and non-invasive manner is not well adapted. Here we show the development of 3D bioelectronic devices based on the electroactive polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) - PEDOT:PSS and their use for non-invasive, electrical monitoring of stem cell growth. We show that the electrical, mechanical and wetting properties as well as the pore size/architecture of 3D PEDOT:PSS scaffolds can be fine-tuned simply by changing the processing crosslinker additive. We present a comprehensive characterization of both 2D PEDOT:PSS thin films of controlled thicknesses, and 3D porous PEDOT:PSS structures made by the freeze-drying technique. By slicing the bulky scaffolds we show that homogeneous, porous 250 um thick PEDOT:PSS slices are produced, generating biocompatible 3D constructs able to support stem cell cultures. These multifunctional membranes are attached on Indium-Tin oxide substrates (ITO) with the help of an adhesion layer that is used to minimize the interface charge resistance. The optimum electrical contact result in 3D devices with a characteristic and reproducible, frequency dependent impedance response. This response changes drastically when human adipose derived stem cells grow within the porous PEDOT:PSS network as revealed by fluorescence microscopy. The increase of these stem cell population within the PEDOT:PSS porous network impedes the charge flow at the interface between PEDOT:PSS and ITO, enabling the interface resistance to be extracted by equivalent circuit modelling, used here as a figure of merit to monitor the proliferation of stem cells. The strategy of controlling important properties of 3D PEDOT:PSS structures simply by altering processing parameters can be applied for development of a number of stem cell in vitro models. We believe the results presented here will advance 3D bioelectronic technology for both fundamental understanding of in vitro stem cell cultures as well as the development of personalized therapies.

bioengineering↗

bioRxiv2019

High-depth resequencing reveals hybrid population and insecticide resistance characteristics of fall armyworm (Spodoptera frugiperda) invading China

The rapid wide-scale spread of fall armyworm (Spodoptera frugiperda) has caused serious crop losses globally. However, differences in the genetic background of subpopulations and the mechanisms of rapid adaptation behind the invasion are still not well understood. Here we report a 393.25-M chromosome-level genome assembly of fall armyworm with scaffold N50 of 13.3 M consisting of 23281 annotated protein-coding genes. Genome-wide resequencing of 105 samples from 16 provinces in China revealed that the fall armyworm population comprises a complex inter-strain hybrid, mainly with the corn-strain genetic background and less of the rice-strain genetic background, which highlights the inaccuracy of strain identification using mitochondrial or Tpi genes. An analysis of genes related to pesticide- and Bt-resistance showed that the risk of fall armyworm developing resistance to conventional pesticides is very high, while remaining currently susceptible to Bt toxins. Laboratory bioassay results showed that insects invading China carry resistance to organophosphate and pyrethroid pesticides, but are sensitive to genetically modified maize expressing Cry1Ab in field experiments. Additionally, we found that two mitochondrial fragments are inserted into the nuclear genome, and the insertion event occurred after the differentiation of the two strains. This study represents a valuable advancement toward the analysis of genetic differences among subpopulations and improving management strategies for fall armyworm.

genomics↗