RESUMEN
Similar to Lepidoptera, the larvae of Trichoptera are also capable of producing silk. Plectrocnemia conspersa, a predatory species belonging to the suborder Annulipalpia, builds massive silken retreats with preycapturing nets. In this study, we describe the silk glands of P. conspersa and use the multi-omics methods to obtain a complete picture of the fiber composition. A combination of silk gland-specific transcriptome and proteomic analyses of the spun-out fibers yielded 27 significant candidates whose full-length sequences and gene structures were retrieved from the publicly available genome database. About one-third of the candidates were completely novel proteins for which there are no described homologs, including a group of five pseudofibroins, proteins with a composition similar to fibroin heavy chain. The rest were homologs of lepidopteran silk proteins, although some had a larger number of paralogs. On the other hand, P. conspersa fibers lacked some proteins that are regular components in moth silk. In summary, the multi-omics approach provides an opportunity to compare the overall composition of silk with other insect species. A sufficient number of such studies will make it possible to distinguish between the basic components of all silks and the proteins that represent the adaptation of the fibers for specific purposes or environments.
RESUMEN
Concentrative nucleoside transporters (Cnts) are unidirectional carriers that mediate the energy-costly influx of nucleosides driven by the transmembrane sodium gradient. Cnts are transmembrane proteins that share a common structural organization and are found in all phyla. Although there have been studies on Cnts from a biochemical perspective, no deep research has examined their role at the organismal level. Here, we investigated the role of the Drosophila melanogaster cnt1 gene, which is specifically expressed in the testes. We used the CRISPR/Cas9 system to generate a mutation in the cnt1 gene. The cnt1 mutants exhibited defects in the duration of copulation and spermatid maturation, which significantly impaired male fertility. The most striking effect of the cnt1 mutation in spermatid maturation was an abnormal structure of the sperm tail, in which the formation of major and minor mitochondrial derivatives was disrupted. Our results demonstrate the importance of cnt1 in male fertility and suggest that the observed defects in mating behavior and spermatogenesis are due to alterations in nucleoside transport and associated metabolic pathways.
RESUMEN
EFLamide (EFLa) is a neuropeptide known for a long time from crustaceans, chelicerates and myriapods. Recently, EFLa-encoding genes were identified in the genomes of apterygote hexapods including basal insect species. In pterygote insects, however, evidence of EFLa was limited to partial sequences in the bed bug (Cimex), migratory locust and a few phasmid species. Here we present identification of a full length EFLa-encoding transcript in the linden bug, Pyrrhocoris apterus (Heteroptera). We created complete null mutants allowing unambiguous anatomical location of this peptide in the central nervous system. Only 2-3 EFLa-expressing cells are located very close to each other near to the surface of the lateral protocerebrum with dense neuronal arborization. Homozygous null EFLa mutants are fully viable and do not have any visible defect in development, reproduction, lifespan, diapause induction or circadian rhythmicity. Phylogenetic analysis revealed that EFLa-encoding transcripts are produced by alternative splicing of a gene that also produces Prohormone-4. However, this Proh-4/EFLa connection is found only in Hemiptera and Locusta, whereas EFLa-encoding transcripts in apterygote hexapods, chelicerates and crustaceans are clearly distinct from Proh-4 genes. The exact mechanism leading to the fused Proh-4/EFLa transcript is not yet determined, and might be a result of canonical cis-splicing, cis-splicing of adjacent genes (cis-SAG), or trans-splicing.