Transcriptome profiling with focus on potential key genes for wing development and evolution in Megaloprepus caerulatus, the damselfly species with the world's largest wings

The evolution, development and coloration of insect wings remains a puzzling subject in evolutionary research. In basal flying insects such as Odonata, genomic research regarding bauplan evolution is still rare. Here we focus on the world’s largest odonate species—the “forest giant” Megaloprepus caerulatus, to explore its potential for looking deeper into the development and evolution of wings. A recently discovered cryptic species complex in this genus previously considered monotypic is characterized by morphological differences in wing shape and color patterns. As a first step toward understanding wing pattern divergence and pathways involved in adaptation and speciation at the genomic level, we present a transcriptome profiling of M. caerulatus using RNA-Seq and compare these data with two other odonate species. The de novo transcriptome assembly consists of 61,560 high quality transcripts and is approximately 93% complete. For almost 75% of the identified transcripts a possible function could be assigned: 48,104 transcripts had a hit to an InterPro protein family or domain, and 28,653 were mapped to a Gene Ontology term. In particular, we focused on genes related to wing development and coloration. The comparison with two other species revealed larva-specific genes and a conserved ‘core’ set of over 8,000 genes forming orthologous clusters with Ischnura elegans and Ladona fulva. This transcriptome may provide a first point of reference for future research in odonates addressing questions surrounding the evolution of wing development, wing coloration and their role in speciation

A call for an immediate ceasefire and peaceful end to the Russian aggression against Ukraine

The Lancet–SIGHT Commission condemns the Russian Government's aggression against Ukraine and its attacks on civilians and civilian infrastructure, including health workers and hospitals. We support the March 2, 2022 UN General Assembly (UNGA) resolution ES-11/1 that “deplores in the strongest terms the aggression by the Russian Federation”. The indiscriminate use of weaponry violates international humanitarian law and has caused catastrophic health impacts, especially on children, older people, and disabled persons, and social and economic disruptions that will be long lasting. There are nuclear risks, both from Russian attacks on Ukrainian nuclear facilities and the potential for nuclear weapons use. There is a further risk that Russia might use chemical or biological weapons. We call for an immediate ceasefire and the appointment of a mediator to facilitate negotiations for a sustainable and peaceful settlement on the basis of international law to end the conflict. We urge the global health community to deliver humanitarian assistance impartially to all those affected by and fleeing the war; document atrocities committed against civilians and the devastating impacts of the war; counter disinformation about the conflict; and advocate for a peaceful settlement. We also call for an end to the repression of those in Russia protesting the war.http://www.thelancet.comhj2023Economic

Human Herpesvirus 8 (HHV8) Sequentially Shapes the NK Cell Repertoire during the Course of Asymptomatic Infection and Kaposi Sarcoma

The contribution of innate immunity to immunosurveillance of the oncogenic Human Herpes Virus 8 (HHV8) has not been studied in depth. We investigated NK cell phenotype and function in 70 HHV8-infected subjects, either asymptomatic carriers or having developed Kaposi's sarcoma (KS). Our results revealed substantial alterations of the NK cell receptor repertoire in healthy HHV8 carriers, with reduced expression of NKp30, NKp46 and CD161 receptors. In addition, down-modulation of the activating NKG2D receptor, associated with impaired NK-cell lytic capacity, was observed in patients with active KS. Resolution of KS after treatment was accompanied with restoration of NKG2D levels and NK cell activity. HHV8-latently infected endothelial cells overexpressed ligands of several NK cell receptors, including NKG2D ligands. The strong expression of NKG2D ligands by tumor cells was confirmed in situ by immunohistochemical staining of KS biopsies. However, no tumor-infiltrating NK cells were detected, suggesting a defect in NK cell homing or survival in the KS microenvironment. Among the known KS-derived immunoregulatory factors, we identified prostaglandin E2 (PGE2) as a critical element responsible for the down-modulation of NKG2D expression on resting NK cells. Moreover, PGE2 prevented up-regulation of the NKG2D and NKp30 receptors on IL-15-activated NK cells, and inhibited the IL-15-induced proliferation and survival of NK cells. Altogether, our observations are consistent with distinct immunoevasion mechanisms that allow HHV8 to escape NK cell responses stepwise, first at early stages of infection to facilitate the maintenance of viral latency, and later to promote tumor cell growth through suppression of NKG2D-mediated functions. Importantly, our results provide additional support to the use of PGE2 inhibitors as an attractive approach to treat aggressive KS, as they could restore activation and survival of tumoricidal NK cells

Summary of transcriptome sequencing and assembly results.

<p>Summary of transcriptome sequencing and assembly results.</p

Most frequent InterPro signatures in orthologous <i>Papaipema</i> genes.

<p>Summary functions shown—see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0191061#pone.0191061.s010" target="_blank">S3 Table</a> for full information.</p

Phylogram of retrotransposons from Hymenoptera, Diptera, and Lepidoptera, including putative Ty1/Copia genes identified in this study.

<p>Phylogram of retrotransposons from Hymenoptera, Diptera, and Lepidoptera, including putative Ty1/Copia genes identified in this study.</p

Summary of methods used.

<p>Summary of methods used.</p

Retrotransposon-related InterPro signatures in orthologs and species-specific genes.

<p>Number of genes shown at top of each bar.</p

Retrotransposon families identified in species-specific genes.

<p>Retrotransposon families identified in species-specific genes.</p