Transcriptomic response of female adult moths to host and non-host plants in two closely related species.

BACKGROUND: Divergent selection has been shown to promote speciation in many taxa and especially in phytophagous insects. In the Ostrinia species complex, the European corn borer (ECB) and adzuki bean borer (ABB) are two sibling species specialized to different host plants. The first is a well-known maize pest, whereas the second is a polyphagous species associated with various dicotyledons. Their specialization to host plants is driven by morphological, behavioral and physiological adaptations. In particular, previous studies have shown that ECB and ABB display marked behavior with regard to plant choice during oviposition, involving specific preference and avoidance mechanisms. In this study, our goal was to identify the mechanisms underlying this host-plant specialization in adult females through an analysis of their gene expression. We assembled and annotated a de novo reference transcriptome and measured differences in gene expression between ECB and ABB females, and between environments. We related differentially expressed genes to host preference behavior, and highlighted the functional categories involved. We also conducted a specific analysis of chemosensory genes, which are considered to be good candidates for host recognition before oviposition. RESULTS: We recorded more differentially expressed genes in ECB than in ABB samples, and noticed that the majority of genes potentially involved in the host preference were different between the two species. At the functional level, the response to plant environment in adult females involved many processes, including the metabolism of carbohydrates, lipids, proteins, and amino acids; detoxification mechanisms and immunity; and the chemosensory repertoire (as expected). Until now, most of the olfactory receptors described in Ostrinia spp. had been tested for their putative role in pheromone recognition by males. Here we observed that one specific olfactory receptor was clearly associated with ECB's discrimination between maize and mugwort conditions, highlighting a potential new candidate involved in plant odor discrimination in adult females. CONCLUSIONS: Our results are a first step toward the identification of candidate genes and functions involved in chemosensory processes, carbohydrate metabolism, and virus and retrovirus dynamics. These candidates provide new avenues for research into understanding the role of divergent selection between different environments in species diversification.

Larval transcriptomic response to host plants in two related phytophagous lepidopteran species: implications for host specialization and species divergence.

BACKGROUND: Most phytophagous insects have morphological, behavioral and physiological adaptations allowing them to specialize on one or a few plant species. Identifying the mechanisms involved in host plant specialization is crucial to understand the role of divergent selection between different environments in species diversification, and to identify sustainable targets for the management of insect pest species. In the present study, we measured larval phenotypic and transcriptomic responses to host plants in two related phytophagous lepidopteran species: the European corn borer (ECB), a worldwide pest of maize, and the adzuki bean borer (ABB), which feeds of various dicotyledons. Our aim was to identify the genes and functions underlying host specialization and/or divergence between ECB and ABB. RESULTS: At the phenotypic level, we observed contrasted patterns of survival, weight gain and developmental time between ECB and ABB, and within ECB and ABB reared on two different host plants. At the transcriptomic level, around 8% of the genes were differentially expressed (DE) between species and/or host plant. 70% of these DE genes displayed a divergent pattern of expression between ECB and ABB, regardless of the host, while the remaining 30% were involved in the plastic response between hosts. We further categorized plastic DE genes according to their parallel or opposite pattern between ECB and ABB to specifically identify candidate genes involved in the species divergence by host specialization. These candidates highlighted a comprehensive response, involving functions related to plant recognition, digestion, detoxification, immunity and development. Last, we detected viral, bacterial, and yeast genes whose incidence contrasted ECB and ABB samples, and maize and mugwort conditions. We suggest that these microorganism communities might influence the survival, metabolism and defense patterns observed in ECB and ABB larvae. CONCLUSIONS: The comprehensive approach developed in the present study allowed to identify phenotypic specialization patterns and underlying candidate molecular mechanisms, and highlighted the putative role of microorganisms in the insect-host plant interaction. These findings offer the opportunity to pinpoint specific and sustainable molecular or physiological targets for the regulation of ECB pest populations.

[Hyperthyroidism caused by metastatic choriocarcinoma. A new male case]. / Hyperthyroïdie par choriocarcinome métastasé. Une nouvelle observation masculine.

The authors report a case of hyperthyroidism induced by a metastatic choriocarcinoma (retroperitoneal, lungs, vertebral and epidural localisations) in a 49 year old man. Tachycardia and possibly weight loss were the only clinical signs of thyrotoxicosis. Chemotherapy led to a remission of hyperthyroidism and tumoral syndrome for 4 months. Neoplasia relapsed and circulating levels of thyroid hormones were increased during the final stages. This is the fifth male reported case of choriocarcinoma associated with hyperthyroidism. Many previous studies suggest that hyperthyroidism is induced by HCG thyroid stimulating activity.

[Spinal anesthesia with bupivacaine. Comparative study of 2 hyperbaric and isobaric solutions]. / Rachianesthésie à la bupivacaïne. Etude comparative de deux solutions hyperbare et isobare.

This study compared two isobaric and hyperbaric solutions of 0.4% bupivacaine used for carrying out spinal anaesthesia in 264 patients more than 70 years old undergoing comparable surgical procedures. With the hyperbaric solution, the mean time of onset of analgesia was shorter: 8.4 +/- 4 min (11.5 +/- 5.1 min with the isobaric solution), the level of analgesia higher by two dermatomes and the mean duration of analgesia longer: 147.3 +/- 24.8 min (121.1 +/- 24.8 min with the isobaric solution). Blood pressure fell more often with the hyperbaric solution. The motor block, assessed by the inability to move the legs and abdominal wall paralysis, was more complete with the hyperbaric solution. Lastly, there were less failures: 3.4% with hyperbaric solution and 12.1% with isobaric solution.