Project description:The availability of viral entry factors is a prerequisite for the cross-species transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Large-scale single-cell screening on animal cells is a powerful tool to reveal the expression patterns of viral entry genes for different hosts. But such exploration for SARS-CoV-2 remained limited. Here, we presented the broadest pan-species single-nucleus RNA sequencing study to date, covering 11 representative species in pets (cat, dog, hamster, lizard), livestock (goat, rabbit), poultry (duck, pigeon) and wildlife (pangolin, tiger, deer), from which we investigated the co-expression of ACE2 and TMPRSS2. Notably, the proportion of SARS-CoV-2 putative target cells in cat was found considerably higher than that of other species investigated in this study, highlighting the necessity to carefully evaluate the role of cats during SARS-CoV-2 circulation. Furthermore, cross-species analysis of comparative lung cell atlas in mammals, reptiles and birds revealed core developmental programs, critical connectomes and conserved regulatory circuits among evolutionarily distant species. Additionally, we developed a user-friendly and freely accessible online platform named PANDORA for researchers to fully exploit the pan-species single cell atlas. Overall, our work provides a compendium of gene expression profiles for non-model animals, which could be employed to identify potential SARS-CoV-2 target cells and narrow down putative zoonotic reservoirs. Alternatively, our resources could also be utilized to illuminate the cellular and molecular mechanisms underlying animal tissue evolution.
Project description:There is growing interest in the study of avian endoparasite communities, and metabarcoding is a promising approach to complement more conventional or targeted methods. In the case of eukaryotic endoparasites, phylogenetic diversity is extreme, with parasites from 4 kingdoms and 11 phyla documented in birds. We addressed this challenge by comparing different primer sets across 16 samples from 5 bird species. Samples consisted of blood, feces, and controlled mixes with known proportions of bird and nematode DNA. Illumina sequencing revealed that a 28S primer set used in combination with a custom blocking primer allowed detection of various plasmodiid parasites and filarioid nematodes in the blood, coccidia in the feces, as well as two potentially pathogenic fungal groups. When tested on the controlled DNA mixes, these primers also increased the proportion of nematode DNA by over an order of magnitude. An 18S primer set, originally designed to exclude metazoan sequences, was the most effective at reducing the relative number of avian DNA sequences and was the only one to detect Trypanosoma in the blood. Expectedly, however, it did not allow nematode detection and also failed to detect avian malaria parasites. This study shows that a 28S set including a blocking primer allows detection of several major and very diverse bird parasite clades, while reliable amplification of all major parasite groups may require a combination of markers. It helps clarify options for bird parasite metabarcoding, according to priorities in terms of the endoparasite clades and the ecological questions researchers wish to focus on.