Comparative mitochondrial genomics of endemic Mexican vesper yellow bats genus Rhogeessa (Chiroptera: Vespertilionidae) and insights into internal relationships in the family Vespertilionidae.

In the species-rich family Vespertilionidae, vesper yellow bats in the genus Rhogeessa include eleven species, three of them endemic to Mexico. These insectivorous bats provide important ecosystem services, including pest control. Even though some aspects of their biology are well- known, only a few genomic resources are available for these species, which limits our understanding of their biology. In this study, we assembled and annotated the mitochondrial genome of four species: R. aenea, R. genowaysi, R. mira, and R. parvula. We generated a phylomitogenomic hypothesis based on translated protein-coding genes for a total of 52 species in the family Vespertilionidae and examined the phylogenetic position of the genus Rhogeessa and species within the family. The AT-rich mitogenomes of R. aenea, R. genowaysi, R. mira, and R. parvula are 16,763, 16,781, 16,807, and 16,794 pb in length, respectively. Each studied mitogenome encodes 13 Protein Coding Genes (PCGs), 22 transfer RNA genes, and 2 rRNA genes, and contains a putative control region (CR). All tRNAs exhibit a 'cloverleaf' secondary structure, except tRNA-Serine-1 that lacked the DHU arm in all studied mitogenomes. Selective pressure analyses indicated that all protein-coding genes are exposed to purifying selection. The phylomitogenomic analysis supported the monophyletic status of the family Vespertilionidae, confirmed the placement of Rhogeessa within the tribe Antrozoini, and clarified phylogenetic relationships within and among subfamilies and tribes in this family. Our results indicate that phylomitogenomics are useful to explore the evolutionary history of vesper bats. The assembly and comprehensive analysis of mitochondrial genomes offer the potential to generate molecular references and resources beneficial for genetic analyses aimed at understanding the ecology and evolution of these remarkable bats.

Cathepsins L and B in Dysdercus peruvianus, Rhodnius prolixus, and Mahanarva fimbriolata. Looking for enzyme adaptations to digestion.

Cysteine peptidases (CP) play a role as digestive enzymes in hemipterans similar to serine peptidases in most other insects. There are two major CPs: cathepsin L (CAL), which is an endopeptidase and cathepsin B (CAB) that is both an exopeptidase and a minor endopeptidase. There are thirteen putative CALs in Dysdercus peruvianus, which in some cases were confirmed by cloning their encoding genes. RNA-seq data showed that DpCAL5 is mainly expressed in the anterior midgut (AM), DpCAL10 in carcass (whole body less midgut), suggesting it is a lysosomal enzyme, and the other DpCALs are expressed in middle (MM) and posterior (PM) midgut. The expression data were confirmed by qPCR and enzyme secretion to midgut lumen by a proteomic approach. Two CAL activities were isolated by chromatography from midgut samples with similar kinetic properties toward small substrates. Docking analysis of a long peptide with several DpCALs modeled with digestive Tenebrio molitor CAL (TmCAL3) as template showed that on adapting to luminal digestion DpCALs (chiefly DpCAL5) changed in relation to their ancestral lysosomal enzyme (DpCAL10) mainly at its S2 subsite. A similar conclusion arrived from structure alignment-based clustering of DpCALs based on structural similarity of the modeled structures. Changes mostly on S2 subsite could mean the enzymes turn out less peptide-bond selective, as described in TmCALs. R. prolixus CALs changed on adapting to luminal digestion, although less than DpCALs. Both D. peruvianus and R. prolixus have two digestive CABs which are expressed in the same extension as CALs, in the first digestive section of the midgut, but less than in the other midgut sections. Mahanarva fimbriolata does not seem to have digestive CALs and their digestive CABs are mainly expressed in the first digestive section of the midgut and do not diverge much from their lysosomal counterparts. The data suggest that CABs are necessary at the initial stage of digestion in CP-dependent Hemipterans, which action is completed by CALs with low peptide-bond selectivity in Heteroptera species. In M. fimbriolata protein digestion is supposed to be associated with the inactivation of sap noxious proteins, making CAB sufficient as digestive CP. Hemipteran genomes and transcriptome data showed that CALs have been recruited as digestive enzymes only in heteropterans, whereas digestive CABs occur in all hemipterans.