Vitellogenin Underwent Subfunctionalization to Acquire Caste and Behavioral Specific Expression in the Harvester Ant Pogonomyrmex barbatus

PMCID: PMC3744404This is an open-access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose. The work is made available under the Creative Commons CC0 public domain dedication

Common and Distinct Roles of Juvenile Hormone Signaling Genes in Metamorphosis of Holometabolous and Hemimetabolous Insects

Insect larvae metamorphose to winged and reproductive adults either directly (hemimetaboly) or through an intermediary pupal stage (holometaboly). In either case juvenile hormone (JH) prevents metamorphosis until a larva has attained an appropriate phase of development. In holometabolous insects, JH acts through its putative receptor Methoprene-tolerant (Met) to regulate Krüppel-homolog 1 (Kr-h1) and Broad-Complex (BR-C) genes. While Met and Kr-h1 prevent precocious metamorphosis in pre-final larval instars, BR-C specifies the pupal stage. How JH signaling operates in hemimetabolous insects is poorly understood. Here, we compare the function of Met, Kr-h1 and BR-C genes in the two types of insects. Using systemic RNAi in the hemimetabolous true bug, Pyrrhocoris apterus, we show that Met conveys the JH signal to prevent premature metamorphosis by maintaining high expression of Kr-h1. Knockdown of either Met or Kr-h1 (but not of BR-C) in penultimate-instar Pyrrhocoris larvae causes precocious development of adult color pattern, wings and genitalia. A natural fall of Kr-h1 expression in the last larval instar normally permits adult development, and treatment with an exogenous JH mimic methoprene at this time requires both Met and Kr-h1 to block the adult program and induce an extra larval instar. Met and Kr-h1 therefore serve as JH-dependent repressors of deleterious precocious metamorphic changes in both hemimetabolous and holometabolous juveniles, whereas BR-C has been recruited for a new role in specifying the holometabolous pupa. These results show that despite considerable evolutionary distance, insects with diverse developmental strategies employ a common-core JH signaling pathway to commit to adult morphogenesis

Clinical characteristics and predictors of complications and mortality in hospitalized octogenarian patients with COVID-19 : an ambispective study

This the study describes the clinical presentation of COVID-19 and the risk factors for complications and death in octogenarian hospitalized patients across the different waves of the disease. The most frequently reported symptoms in hospitalized octogenarian patients were fever, cough, dyspnea, and asthenia with acute respiratory distress syndrome, renal failure, and delirium being the most frequent complications. Regarding complications, diabetes mellitus, heart failure, dyspnea, and higher baseline levels of creatinine were identified as risk factors, while a higher Barthel index and presence of cough were found to be protective. Age, dyspnea, abnormal bilateral chest x-ray, CRP, and sodium were identified as risk factors for death. These findings could be valuable for managing future pandemics by contributing to tailored interventions and strategies to reduce COVID-19 mortality and complications in this patient group

The maternal and early embryonic transcriptome of the milkweed bug Oncopeltus fasciatus

<p>Abstract</p> <p>Background</p> <p>Most evolutionary developmental biology ("evo-devo") studies of emerging model organisms focus on small numbers of candidate genes cloned individually using degenerate PCR. However, newly available sequencing technologies such as 454 pyrosequencing have recently begun to allow for massive gene discovery in animals without sequenced genomes. Within insects, although large volumes of sequence data are available for holometabolous insects, developmental studies of basally branching hemimetabolous insects typically suffer from low rates of gene discovery.</p> <p>Results</p> <p>We used 454 pyrosequencing to sequence over 500 million bases of cDNA from the ovaries and embryos of the milkweed bug <it>Oncopeltus fasciatus</it>, which lacks a sequenced genome. This indirectly developing insect occupies an important phylogenetic position, branching basal to Diptera (including fruit flies) and Hymenoptera (including honeybees), and is an experimentally tractable model for short-germ development. 2,087,410 reads from both normalized and non-normalized cDNA assembled into 21,097 sequences (isotigs) and 112,531 singletons. The assembled sequences fell into 16,617 unique gene models, and included predictions of splicing isoforms, which we examined experimentally. Discovery of new genes plateaued after assembly of ~1.5 million reads, suggesting that we have sequenced nearly all transcripts present in the cDNA sampled. Many transcripts have been assembled at close to full length, and there is a net gain of sequence data for over half of the pre-existing <it>O. fasciatus </it>accessions for developmental genes in GenBank. We identified 10,775 unique genes, including members of all major conserved metazoan signaling pathways and genes involved in several major categories of early developmental processes. We also specifically address the effects of cDNA normalization on gene discovery in <it>de novo </it>transcriptome analyses.</p> <p>Conclusions</p> <p>Our sequencing, assembly and annotation framework provide a simple and effective way to achieve high-throughput gene discovery for organisms lacking a sequenced genome. These data will have applications to the study of the evolution of arthropod genes and genetic pathways, and to the wider evolution, development and genomics communities working with emerging model organisms.</p> <p>[The sequence data from this study have been submitted to GenBank under study accession number SRP002610 (<url>http://www.ncbi.nlm.nih.gov/sra?term=SRP002610</url>). Custom scripts generated are available at <url>http://www.extavourlab.com/protocols/index.html</url>. Seven Additional files are available.]</p

microRNAs and regulation of insect oogenesis

Comunicación oral presentada al 8º Congreso de la Asociacion Ibérica de Endocrinología comparada, celebrado en Madrid, entre los días 5 y 7 de septiembre de 2011.In insects, many aspects of reproduction are under the control of hormones, which regulate the synthesis and uptake of yolk proteins, oocyte growth, cell proliferation, chorion synthesis, and apoptosis in ovarian tissues. But most of the genes that participate in these processes are not directly regulated by hormones, thus being good candidates to be regulated by microRNAs (miRNAs). The discovery of non-coding small RNAs, including miRNAs, deeply changed the knowledge on the control of gene expression. In insects, information about miRNAs is still fragmentary and predominantly focused on Drosophila melanogaster. In this species, the processes studied go from neural development, metamorphosis, growth and development, to oogenesis. Our research aims at unveiling how miRNAs are involved in controlling gene expression in insect oogenesis, taking as a model the cockroach Blattella germanica, a phylogenetically basal species with panoistic ovaries. To this end, we recently obtained a library of small RNAs from B. germanica adult ovaries to identify the miRNAs of this cockroach; then, we used quantitative PCR (qPCR) to study the expression of a selection of them. and we are silencing specific miRNAs in order to unveil their function during oogenesis. Data afforded by these approaches, concerning classical miRNAs and novel miRNA candidates, are changing our views about the regulation of insect oogenesis.Peer Reviewe