Genetic characterisation of the Theileria annulata cytochrome b locus and its impact on buparvaquone resistance in bovine

Control of tropical theileriosis, caused by the apicomplexan Theileria annulata, depends on the use of a single drug, buparvaquone, the efficacy of which is compromised by the emergence of resistance. The present study was undertaken to improve understanding of the role of mutations conferring buparvaquone resistance in T. annulata, and the effects of selection pressures on their emergence and spread. First, we investigated genetic characteristics of the cytochrome b locus associated with buparvaquone resistance in 10 susceptible and 7 resistant T. annulata isolates. The 129G (GGC) mutation was found in the Q binding pocket and 253S (TCT) and 262S (TCA) mutations were identified within the Q binding pocket. Next, we examined field isolates and identified cytochrome b mutations 129G (GGC), 253S (TCT) and 262S (TCA) in 21/75 buffalo-derived and 19/119 cattle-derived T. annulata isolates, providing evidence of positive selection pressure. Both hard and soft selective sweeps were identified, with striking differences between isolates. For example, 19 buffalo-derived and 7 cattle-derived isolates contained 129G (GGC) and 253S (TCT) resistance haplotypes at a high frequency, implying the emergence of resistance by a single mutation. Two buffalo-derived and 12 cattle-derived isolates contained equally high frequencies of 129G (GGC), 253S (TCT), 129G (GGC)/253S (TCT) and 262S (TCA) resistance haplotypes, implying the emergence of resistance by pre-existing or recurrent mutations. Phylogenetic analysis further revealed that 9 and 21 unique haplotypes in buffalo and cattle-derived isolates were present in a single lineage, suggesting a single origin. We propose that animal migration between farms is an important factor in the spread of buparvaquone resistance in endemic regions of Pakistan. The overall outcomes will be useful in understanding how drug resistance emerges and spreads, and this information will help design strategies to optimise the use and lifespan of the single most drug use to control tropical theileriosis. [Abstract copyright: Copyright © 2022. Published by Elsevier Ltd.

Engineering Attenuated Virulence of a Theileria annulata–Infected Macrophage

International audienceLive attenuated vaccines are used to combat tropical theileriosis in North Africa, the Middle East, India, and China. The attenuation process is empirical and occurs only after many months, sometimes years, of in vitro culture of virulent clinical isolates. During this extensive culturing, attenuated lines lose their vaccine potential. To circumvent this we engineered the rapid ablation of the host cell transcription factor c-Jun, and within only 3 weeks the line engineered for loss of c-Jun activation displayed in vitro correlates of attenuation such as loss of adhesion, reduced MMP9 gelatinase activity, and diminished capacity to traverse Matrigel. Specific ablation of a single infected host cell virulence trait (c-Jun) induced a complete failure of Theileria annulata–transformed macrophages to disseminate, whereas virulent macrophages disseminated to the kidneys, spleen, and lungs of Rag2/cC mice. Thus, in this heterologous mouse model loss of c-Jun expression led to ablation of dissemination of T. annulata–infected and transformed macrophages. The generation of Theileria-infected macrophages genetically engineered for ablation of a specific host cell virulence trait now makes possible experimental vaccination of calves to address how loss of macrophage dissemination impacts the disease pathology of tropical theileriosis. Citation: Echebli N, Mhadhbi M, Chaussepied M, Vayssettes C, Di Santo JP, et al. (2014) Engineering Attenuated Virulence of a Theileria annulata–Infected Macrophage. PLoS Negl Trop Dis 8(11): e3183

Micro-multigeneration prospects for residential applications in Italy

The development of multigeneration systems is evolving in different directions. One of the main directions is the extended application of the technologies at smaller sizes. Micro-multigeneration solutions aim at becoming competitive at the size of the residential users. The cost of the technologies, in particular the cost of the cogenerator, is a major limitation to the diffusion of micro-multigeneration, especially in countries (e.g., Italy) where residential customers have a limited usage of electricity to supply their facilities. This paper discusses the prospects for the application of micro-multigeneration in Italy. The modelling and analysis of a residential micromultigeneration system are developed from the energy efficiency and economic assessment viewpoints. The analysis is carried out on a typical system composed of a natural gas internal combustion engine, a small-scale photovoltaic plant, a backup boiler, thermal energy storage and electrical energy storage. A specific analysis tool has been implemented to address the operational planning of this system during a time period of one year. The whole model has been constructed from real data of thermal and electrical demand in a housing complex in Italy. The annual running cost and the primary energy savings occurring to serve the multi-energy demand have been considered in the operational assessment. From an economical viewpoint, the model considers the price of natural gas related to the cogeneration system, the electricity prices and all the tax breaks allowed in Italy. In this way, different scenarios have been constructed and assessed. The results indicate the impact of providing incentives on the purchase cost of the technologies, leading to increase the diffusion of micro-multigeneration solutions for the residential sector in the next years