Biology subjects

Lucas, V.

Publications and source records attributed to Lucas, V..

3 recordsLinked to original sources

bioRxiv2021

Study of Metyltetraprole, an unusual agrofungicide targeting the Qo-site of cytochrome bc1 complex

The mitochondrial respiratory chain bc1 complex is a proven target of agrofungicides. Most of them are Qo-site antagonists (i.e QoIs), competing with the substrate ubiquinol, and likely share the same binding mode as the widespread Qo-site resistance mutation G143A confers cross-resistance. Metyltetraprole (MTP) presents an exception as studies with phytopathogenic fungi showed that the inhibitor was unaffected by G143A. Here, we used the yeast model to investigate its mode of action. Analysis of bc1 complex mutants supports a Qo-site binding for MTP. However the compound seems distinct to other QoIs, such as azoxystrobin, in various ways, namely; 1) G143A was without effect on MTP, as previously reported. 2) The level of MTP resistance of mutants was higher in bc1 complex activity assays than in growth assays while the opposite was observed with azoxystrobin. 3) Steady-state kinetics used to characterise the mode of action of MTP also revealed differences compared to other QoIs.

biochemistry↗

bioRxiv2020

Prophylactic intranasal administration of a TLR2 agonist reduces upper respiratory tract viral shedding in a SARS-CoV-2 challenge ferret model

Respiratory viruses such as coronaviruses represent major ongoing global threats, causing epidemics and pandemics with huge economic burden. Rapid spread of virus through populations poses an enormous challenge for outbreak control. Like all respiratory viruses, the most recent novel human coronavirus SARS-CoV-2, initiates infection in the upper respiratory tract (URT). Infected individuals are often asymptomatic, yet highly infectious and readily transmit virus. A therapy that restricts initial replication in the URT has the potential to prevent progression of severe lower respiratory tract disease as well as limiting person-to-person transmission. We show that prophylactic intra-nasal administration of the TLR2/6 agonist INNA-051 in a SARS-CoV-2 ferret infection model effectively reduces levels of viral RNA in the nose and throat. The results of our study support clinical development of a therapy based on prophylactic TLR2/6 innate immune activation in the URT to reduce SARS-CoV-2 transmission and provide protection against COVID-19.

immunology↗

bioRxiv2020

Comparison of Rhesus and Cynomolgus macaques as an authentic model for COVID-19.

A novel coronavirus, SARS-CoV-2, has been identified as the causative agent of the current COVID-19 pandemic. Animal models, and in particular non-human primates, are essential to understand the pathogenesis of emerging diseases and to the safety and efficacy of novel vaccines and therapeutics. Here, we show that SARS-CoV-2 replicates in the upper and lower respiratory tract and causes pulmonary lesions in both rhesus and cynomolgus macaques, resembling the mild clinical cases of COVID-19 in humans. Immune responses against SARS-CoV-2 were also similar in both species and equivalent to those reported in milder infections and convalescent human patients. Importantly, we have devised a new method for lung histopathology scoring that will provide a metric to enable clearer decision making for this key endpoint. In contrast to prior publications, in which rhesus are accepted to be the optimal study species, we provide convincing evidence that both macaque species authentically represent mild to moderate forms of COVID-19 observed in the majority of the human population and both species should be used to evaluate the safety and efficacy of novel and repurposed interventions against SARS-CoV-2. Accessing cynomolgus macaques will greatly alleviate the pressures on current rhesus stocks.

microbiology↗