Nelson Bay Reovirus Isolated from Bats and Blood-Sucking Arthropods Collected in Yunnan Province, China

The ACE2 Receptor from Common Vampire Bat (Desmodus rotundus) and Pallid Bat (Antrozous pallidus) Support Attachment and Limited Infection of SARS-CoV-2 Viruses in Cell Culture

During the COVID-19 pandemic, severe acute respiratory syndrome coronavirus 2 (SC2) infection was confirmed in various animal species demonstrating a wide host range of the virus. Prior studies have shown that the ACE2 protein is the primary receptor used by the virus to gain cellular entry and begin the replication cycle. In previous studies, we demonstrated that human and various bat ACE2 proteins can be utilized by SC2 viruses for entry. Bats are a suspected natural host of SC2 because of genetic homology with other bat coronaviruses. In this work, we demonstrate that expression of ACE2 genes from the common vampire bat (CVB) (Desmodus rotundus) and the pallid bat (PB) (Antrozous pallidus), supports infection and replication of some SC2 viruses in cell culture. Two cell lines were produced, CVB-ACE2 and PB-ACE2, expressing ACE2 from these bat species along with human TMPRSS2, in a model previously established using a non-permissive chicken DF-1 cell line. Results demonstrate that the original Wuhan lineage (WA1) virus and the Delta variant were able to infect and replicate in either of the bat ACE2 cell lines. In contrast, the Lambda and Omicron variant viruses infected both cell lines, but viral titers did not increase following infection. Viral detection using immunofluorescence demonstrated abundant spike (S) protein staining for the WA1 and Delta variants but little signal for the Lambda and Omicron variants. These studies demonstrate that while ACE2 from CVB and PB can be utilized by SC2 viruses to gain entry for infection, later variants (Lambda and Omicron) replicate poorly in these cell lines. These observations suggest more efficient human adaption in later SC2 variants that become less fit for replication in other animal species.

The complete mitochondrial genome of Brachytarsina amboinensis (Diptera: Hippoboscoidea: Streblidae) provides new insights into phylogenetic relationships of Hippoboscoidea

The family Streblidae is a significant grouping of dipteran insects within the superfamily Hippoboscoidea, which parasitizes the body surface of bats. With the global spread of bat-related pathogens in recent years, Streblidae has gained increasing attention due to its potential for pathogen transmission. A sample of Brachytarsina amboinensis was sequenced on the B. amboinensis were obtained, compared with available Streblidae mitogenomes, and the phylogeny of Hippoboscoidea was reconstructed. The results indicate that the mitochondrial genome of B. amboinensis exhibits a relatively high degree of conservation, with an identical gene count, arrangement, and orientation as the ancestral insect's genome. Base composition analysis revealed a strong bias towards A and T in the base composition. Selection pressure analysis indicated strong purifying selection acting on cox1. Pairwise genetic distance analysis showed that cox1 evolved at a relatively slow rate. Regarding phylogenetic relationships, the constructed phylogenetic trees using Bayesian inference and Maximum Likelihood methods supported the monophyly of the Hippoboscoidea, Glossinidae, Hippoboscidae, and Nycteribiidae clades, with high nodal support values. Our research confirmed the paraphyly of the families Streblidae. In the familial relations between Nycteribiidae and Streblidae, New World Streblidae share a closer kinship with Nycteribiidae. This contrasts with prior findings which indicated that Old World Streblidae share a closer kinship with Nycteribiidae. This study not only enhances the molecular database for bat flies but also provides a valuable reference for the identification and phylogenetic analysis of Streblidae.

Human cytokeratin 1 plays a role in the interaction of Pteropine orthoreovirus with Hek293 cells but not HeLa cells

Pteropine orthoreovirus (PRV) causes respiratory tract infections in humans. Despite its emergence as a zoonotic and respiratory virus, little is known about its cell tropism, which hampers progress in fully understanding its pathogenesis in humans. Hek293 cells are most susceptible to PRV infection, while HeLa cells are the least. Human cytokeratin 1 (CK1) was identified as the protein that interacts with PRV. The immunofluorescence assay and qPCR results revealed prior treatment with anti-CK1 may provide Hek293 cells protection against PRV. The KRT1-knockout Hek293 cells were less susceptible to PRV infection. Further study into the pathogenesis of PRV in humans is needed.