Wolbachia is a genus of intracellular symbiotic bacteria that are widely distributed in arthropods and nematodes. These maternally inherited bacteria regulate host reproductive systems in various ways to facilitate their vertical transmission. Since the identi cation of Wolbachia in many insects, the relationship between Wolbachia and the host has attracted great interest. Numerous studies have indicated that Wolbachia modi es a variety of biological processes in the host. Previous studies in Drosophila melanogaster (D. mel) have demonstrated that Wolbachia can affect spermatid differentiation, chromosome deposition, and sperm activity in the early stages of spermatogenesis, leading to sperm dysfunction. Here, we explored the putative effect of Wolbachia in sperm maturation using transcriptomic approaches to compare gene expression in Wolbachia-infected and Wolbachia-free D. mel adult testes. Our ndings show that Wolbachia affects many biological processes in D. mel adult testes, and most of the differentially expressed genes involved in carbohydrate metabolism, lysosomal degradation, proteolysis, lipid metabolism, and immune response were upregulated in the presence of Wolbachia. In contrast, some genes that are putatively associated with cutin and wax biosynthesis and peroxisome pathways were downregulated. We did not nd any differentially expressed genes that are predicted to be related to spermatogenesis in the datasets. This work provides additional information for understanding the Wolbachia-host intracellular relationships.

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In this study, we detected African Swine Fever Virus (ASFV) in Dermacentor (Ixodidae) from sheep and bovines using small RNA sequencing. To validate this result, a 235-bp DNA segment was detected in a number of DNA samples from D. silvarum and sheep blood. This 235-bp segment had an identity of 99% to a 235-bp DNA segment of ASFV and contained three single nucleotide mutations (C38T, C76T and A108C). C38T, resulting in a single amino acid mutation G66D, suggests the existence of a new ASFV strain, which is different from all reported ASFV strains in the NCBI GenBank database and the ASFV strain (GenBank: MH713612.1) reported in China in 2018. To further confirm the existence of ASFV in Dermacentor ticks, three DNA segments of ASFV were detected in D. niveus females from bovines and their first generation ticks reared in our lab. These results also proved that transovarian transmission of ASFV occurs in hard ticks. This study revealed for the first time that ASFV has a wider range of hosts (e.g. sheep and bovines) and vectors (e.g. hard ticks), beyond the well-known Suidae family and Argasidae (soft ticks). Our findings pave the way toward further studies on ASFV transmission and the development of prevention and control measures.

Wolbachia are the most widely distributed intracellular bacteria, and their most common effect on host phenotype is cytoplasmic incompatibility (CI). A variety of models have been proposed to decipher the molecular mechanism of CI, among which the host modification (HM) model predicts that Wolbachia effectors play an important role in sperm modification. However, owing to the complexity of spermatogenesis and testicular cell-type heterogeneity, whether Wolbachia have different effects on cells at different stages of spermatogenesis or whether these effects are linked with CI remains unknown. Therefore, we used single-cell RNA sequencing to analyse gene expression profiles in adult male Drosophila testes that were infected or uninfected by Wolbachia . We found that Wolbachia significantly affected the proportion of different types of germ cells and affected multiple metabolic pathways in germ cells. Most importantly, Wolbachia had the greatest impact on germline stem cells, resulting in dysregulated expression of genes related to DNA compaction, and Wolbachia infection also influenced the histone-to-protamine transition in the late stage of sperm development. These results support the HM model and suggest that future studies on Wolbachia -induced CI should focus on cells in the early stages of spermatogenesis.

Insects have a long history of being used in medicine, with clear primary and secondary functions and less side effects, and the study and exploitation of medicinal insects have received increasing attention. Insects gut microbiota and their metabolites play an important role in protecting the hosts from other potentially harmful microbes, providing nutrients, promoting digestion and degradation, and regulating growth and metabolism of the hosts. However, there are still few studies linking the medicinal values of insects with their gut microbes. In this study, we focused on the specific gut microbiota common to medicinal insects, hoping to trace the potential connection between medicinal values and gut microbes of medicinal insects. Based on 16S rRNA gene sequencing data, we compared the gut microbiota of medicinal insects [Periplaneta americana, Protaetia (Liocola) brevitarsis (Lewis) and Musca domestica], in their medicinal stages, and non-medicinal insects (Hermetia illucens L., Tenebrio molitor, and Drosophila melanogaster), and found that the intestinal microbial richness of medicinal insects was higher, and there were significant differences in the microbial community structure between the two groups. We established a model using a random-forest method to preliminarily screen out several types of gut microbiota common to medicinal insects that may play medicinal values: Parabacteroides goldsteinii, Lactobacillus dextrinicus, Bifidobacterium longum subsp. infantis (B. infantis), and Vagococcus carniphilus. In particular, P. goldsteinii and B. infantis were most probably involved in the anti-inflammatory effects of medicinal insects. Our results revealed an association between medicinal insects and their gut microbes, providing new development directions and possibly potential tools for utilizing microbes to enhance the medicinal efficacy of medicinal insects.