Publications

4467

Asgard archaea have recently been identified as the closest archaeal relatives of eukaryotes. Their ecology remains enigmatic, and their virome, completely unknown. Here, we describe the closed genome of Ca. Odinarchaeum yellowstonii LCB_4, and, from this, obtain novel CRISPR arrays with spacer targets to several viral contigs. We find related viruses in sequence data from thermophilic environments and in the genomes of diverse prokaryotes, including other Asgard archaea. These novel viruses open research avenues into the ecology and evolution of Asgard archaea.

Abstract“Candidatus Liberibacter asiaticus” (Ca. L. asiaticus) is the causal agent of Huanglongbing disease of citrus and current study focuses on the discovery of novel small‐molecule inhibitors against SecA protein of Ca. L. asiaticus. In this study, homologous modeling was used to construct the three‐dimensional structure of SecA. Then, molecular docking‐based virtual screening and two rounds of in vitro bacteriostatic experiments were utilized to identify novel small‐molecule inhibitors of SecA. Encouragingly, 93 compounds were obtained and two of them (P684‐2850, P684‐3808) showed strong antimicrobial activities against Liberibacter crescens BT‐1 in bacteriostatic experiments. Finally, molecular dynamics simulations were employed to explore the binding modes of the receptor–ligand complexes. Results in MD simulations showed that compound P684‐3808 was relatively stable during simulation, while compound P684‐2850 left the binding pocket. Compound P684‐3808 might be suitable as a lead compound for further development of antimicrobial compounds against SecA of Ca. L. asiaticus.

Abstract Culicoides biting midges (Diptera: Ceratopogonidae) are vectors responsible for the transmission of several viruses of veterinary importance. Previous screens of Culicoides have described the presence of the endosymbiont Candidatus Cardinium hertigii (Bacteroidetes). However, any impacts of this microbe on vectorial capacity, akin to those conferred by Wolbachia in mosquitoes, are yet to be uncovered and await a suitable system to study Cardinium ‐midge interactions. To identify potential candidate species to investigate these interactions, accurate knowledge of the distribution of the endosymbiont within Culicoides populations is needed. We used conventional and nested PCR assays to screen Cardinium infection in 337 individuals of 25 Culicoides species from both Palearctic and Afrotropical regions. Infections were observed in several vector species including C. imicola and the Pulicaris complex ( C. pulicaris , C. bysta , C. newsteadi and C. punctatus ) with varying prevalence. Phylogenetic analysis based on the Gyrase B gene grouped all new isolates within ‘group C’ of the genus, a clade that has to date been exclusively described in Culicoides . Through a comparison of our results with previous screens, we suggest C. imicola and C. sonorensis represent good candidates for onward study of Cardinium‐ midge interactions.

Novymonas esmeraldas is a parasitic flagellate of the family Trypanosomatidae representing the closest insect-restricted relative of the human pathogen Leishmania . It bears symbiotic bacteria in its cytoplasm, the relationship with which has been established relatively recently and independently from other known endosymbioses in protists.

Ca . Bathyarchaeia MAGs from terrestrial hot spring habitats are poorly revealed, though they have been studied extensively in marine ecosystems.

Recent advances in sequencing technology promoted the blowout discovery of super tiny microbes in the Diapherotrites , Parvarchaeota , Aenigmarchaeota , Nanoarchaeota , and Nanohaloarchaeota (DPANN) superphylum. However, the unculturable properties of the majority of microbes impeded our investigation of their behavior and symbiotic lifestyle in the corresponding community.