Haley, Maisy, Bertrand, Jeanri, Anderson, Vanessa Torrico, Fuad, Mukattar, Frenguelli, Bruno G., Corrêa, Sônia A. L. and Wall, Mark J.

Expression of the immediate early gene Arc/Arg3.1 (Arc), a key mediator of synaptic plasticity, is enhanced by neural activity and then reduced by proteasome-dependent degradation. We have previously shown that disruption of Arc degradation, in an Arc knock-in mouse (ArcKR), where the predominant Arc ubiquitination sites were mutated, reduced the threshold to induce, and also enhanced, the strength of Group I metabotropic glutamate receptor-mediated long- term depression (DHPG-LTD). Here we have investigated if ArcKR expression changes long- term potentiation (LTP) in CA1 area of the hippocampus. Our findings support the hypothesis that Arc ubiquitination supports the induction and expression of LTP, likely via limiting Arc-dependent removal of AMPA receptors at synapses.

European Journal of Neuroscience. October 2023

Chan, Y. L. Elaine, Irvine, Michael A., Prystajecky, Natalie, Sbihi, Hind, Marsha, Taylor, Joffres , Yayuk, Schertzer, Andrea, Rose, Caren, Dyson, Louise, Hill, Edward M., Tildesley, Michael J., Tyson, John R., Hoang, Linda M. N. and Galanis, Eleni

In British Columbia, Canada, initial growth of the SARS-CoV-2 Delta variant was slower than that reported in other jurisdictions. We describe the growth of Delta variant cases in British Columbia during March1 – June 20 2021, and apply retrospective counterfactual modelling to examine factors for the initially low COVID-19 case rate after Delta introduction, such as vaccination coverage and nonpharmaceutical interventions. Grwth of COVID-19 cases in the first 3 months after Delta emergence was likely limited in British Columbia because additional nonpharmaceutical interventions were implemented.

Emerging Infectious Diseases.October 2023

Yinwei Zeng, Inge Verstraeten, Hoang Khai Trinh, Robin Lardon, Sebastien Schotte, Damilola Olatunji, Thomas Heugebaert, Christian Stevens, Mussa Quareshy, Richard Napier, Sara Paola Nastasi, Alex Costa, Bert De Rybel, Catherine Bellini, Tom Beeckman, Steffen Vanneste, Danny Geelen

Upon exposure to light, etiolated Arabidopsis seedlings form adventitious roots (AR) along the hypocotyl. While processes underlying lateral root formation are studied intensively, comparatively little is known about the molecular processes involved in the initiation of hypocotyl AR. AR and LR formation were studied using a small molecule named Hypocotyl Specific Adventitious Root INducer (HYSPARIN) that strongly induces AR but not LR formation. Analysis of HYSPARIN-induced AR formation uncovers an evolutionary conservation of auxin signalling controlling LR and AR induction in Arabidopsis seedlings and identifies SAUR19, OFP4 and AGC2 kinase as novel regulators of AR formation.

New Phytologist. October 2023

CK Cassidy, Zhuan Qin, Thomas Frosio, Khoosheh Gosink, Zhengyi Yang, Mark Sansom, Phillip Stansfeld, John Parkinson, and Peijun Zhang

The sensory apparatus of the chemotaxis pathway is an array of core-signaling units (CSUs) composed of transmembrane chemoreceptors, the histidine kinase CheA and an adaptor protein, CheW. Although chemotaxis pathways represent the best understood signaling systems, a detailed mechanistic understanding of signal transduction has been hindered by the lack of a complete structural picture of the CSU and extended array. In this study, we present the structure of the complete CSU from phage ϕX174 E protein lysed Escherichia coli cells, determined using cryo-electron tomography and sub-tomogram averaging to 12-Å resolution. Our results provide new insight into previously poorly-resolved regions of the complex and offer a structural basis for designing new experiments to test mechanistic hypotheses.

mBio. September 2023

Aina Mercant Osuna, Alexandra Gidley, Marie Paul Audrey Mayi, Roland Bamou, Vishaal Dhokiya, Christophe Antonio-Nkondjio, Claire Louise Jeffries, Thomas Walker

The endosymbiotic bacterium Wolbachia infects numerous species of insects and Wolbachia transinfection of Aedes mosquito species is now being used for biocontrol programs as Wolbachia strains can both inhibit arboviruses and invade wild mosquito populations. The discovery of novel, resident Wolbachia strains in mosquito species warrants further investigation as potential candidate strains for biocontrol strategies. We obtained mosquito specimens from diverse Culicine mosquitoes from Cameroon including ecologically diverse locations in the Central and West Regions. Wolbachia prevalence rates were assessed in addition to the environmentally acquired bacterial species Asaia in major Culicine genera Our study provides further evidence that Wolbachia is widespread within wild mosquito populations of diverse Culicine species and provides further candidate strains that could be investigated as future options for Wolbachia-based biocontrol to inhibit arbovirus transmission.

Wellcome Open Research. September 2023

Arturo Torres Ortiz, Michelle Kendall, Nathaniel Storey, James Hatcher, Helen Dunn, Sunando Roy, Rachel Williams, Charlotte Williams, Richard A Goldstein, Xavier Didelot, Kathryn Harris, Judith Breuer, Louis Grandjean

Accurate inference of who infected whom in an infectious disease outbreak is critical for the delivery of effective infection prevention and control. We hypothesized that including within-sample variation in a phylogenetic model would help to identify who infected whom in instances in which this was previously impossible. Using whole-genome sequences from SARS-CoV-2 multi-institutional outbreaks as an example, we show how within-sample diversity is partially maintained among repeated serial samples from the same host, it can transmitted between those cases with known epidemiological links, and how this improves phylogenetic inference and our understanding of who infected whom. Our technique is applicable to other infectious diseases and has immediate clinical utility in infection prevention and control.

eLife. September 2023