Toxic effects of Ricinus communis non-protein trypsin inhibitor on Spodoptera frugiperda (J. E. Smith) (Lepidoptera:Noctuidae)

In the study reported herein, we aimed to isolate a trypsin inhibitor from Ricinus communis leaves through chromatographic and spectrometric techniques and evaluate its toxic effects on the development of Spodoptera frugiperda larvae. Plant extracts were submitted to fractionation in adsorption column. The fraction 10, which showed the highest inhibitory activity, were incorporated into an artificial diet at the concentrations of 0, 0.06, 0.12, 0.25 and 0.5%, and offered to S. frugiperda larvae. Fresh weight of larvae, food consumed and weight of eliminated faeces were registered. Based on these parameters the following nutritional index were calculated: Relative Consumption Rate (RCR), Relative Metabolic Rate (RMR), Relative Growth Rate (RGR), Approximated Digestibility (AD), Efficiency of Ingested Food Conversion (EIC), Efficiency of Digested Food Conversion (EDC) and the Metabolic Cost (100 - EDC). The inhibitor at 0.5% concentration was deleterious to S. frugiperda, extending the larval stage in 11 days, with higher RCR and ECD, and lower RGR, ECI and ECD. Therefore, the trypsin inhibitor from leaves of R. communis affected the S. frugiperda larval development, being promising in studies of alternative and sustainable control methods for lepidopteran pest species.Keywords: Castor beans, enzymatic inhibition, integrated pest management, plant defense against herbivor

Hyperoxemia and excess oxygen use in early acute respiratory distress syndrome : Insights from the LUNG SAFE study

Publisher Copyright: © 2020 The Author(s). Copyright: Copyright 2020 Elsevier B.V., All rights reserved.Background: Concerns exist regarding the prevalence and impact of unnecessary oxygen use in patients with acute respiratory distress syndrome (ARDS). We examined this issue in patients with ARDS enrolled in the Large observational study to UNderstand the Global impact of Severe Acute respiratory FailurE (LUNG SAFE) study. Methods: In this secondary analysis of the LUNG SAFE study, we wished to determine the prevalence and the outcomes associated with hyperoxemia on day 1, sustained hyperoxemia, and excessive oxygen use in patients with early ARDS. Patients who fulfilled criteria of ARDS on day 1 and day 2 of acute hypoxemic respiratory failure were categorized based on the presence of hyperoxemia (PaO2 > 100 mmHg) on day 1, sustained (i.e., present on day 1 and day 2) hyperoxemia, or excessive oxygen use (FIO2 ≥ 0.60 during hyperoxemia). Results: Of 2005 patients that met the inclusion criteria, 131 (6.5%) were hypoxemic (PaO2 < 55 mmHg), 607 (30%) had hyperoxemia on day 1, and 250 (12%) had sustained hyperoxemia. Excess FIO2 use occurred in 400 (66%) out of 607 patients with hyperoxemia. Excess FIO2 use decreased from day 1 to day 2 of ARDS, with most hyperoxemic patients on day 2 receiving relatively low FIO2. Multivariate analyses found no independent relationship between day 1 hyperoxemia, sustained hyperoxemia, or excess FIO2 use and adverse clinical outcomes. Mortality was 42% in patients with excess FIO2 use, compared to 39% in a propensity-matched sample of normoxemic (PaO2 55-100 mmHg) patients (P = 0.47). Conclusions: Hyperoxemia and excess oxygen use are both prevalent in early ARDS but are most often non-sustained. No relationship was found between hyperoxemia or excessive oxygen use and patient outcome in this cohort. Trial registration: LUNG-SAFE is registered with ClinicalTrials.gov, NCT02010073publishersversionPeer reviewe

Pleiotropic Impact of Endosymbiont Load and Co-Occurrence in the Maize Weevil <i>Sitophilus zeamais</i>

<div><p>Individual traits vary among and within populations, and the co-occurrence of different endosymbiont species within a host may take place under varying endosymbiont loads in each individual host. This makes the recognition of the potential impact of such endosymbiont associations in insect species difficult, particularly in insect pest species. The maize weevil, <i>Sitophilus zeamais</i> Motsch. (Coleoptera: Curculionidae), a key pest species of stored cereal grains, exhibits associations with two endosymbiotic bacteria: the obligatory endosymbiont SZPE (<i>“Sitophilus zeamais</i> Primary Endosymbiont”) and the facultative endosymbiont <i>Wolbachia</i>. The impact of the lack of SZPE in maize weevil physiology is the impairment of nutrient acquisition and energy metabolism, while <i>Wolbachia</i> is an important factor in reproductive incompatibility. However, the role of endosymbiont load and co-occurrence in insect behavior, grain consumption, body mass and subsequent reproductive factors has not yet been explored. Here we report on the impacts of co-occurrence and varying endosymbiont loads achieved via thermal treatment and antibiotic provision via ingested water in the maize weevil. SZPE exhibited strong effects on respiration rate, grain consumption and weevil body mass, with observed effects on weevil behavior, particularly flight activity, and potential consequences for the management of this pest species. <i>Wolbachia</i> directly favored weevil fertility and exhibited only mild indirect effects, usually enhancing the SZPE effect. SZPE suppression delayed weevil emergence, which reduced the insect population growth rate, and the thermal inactivation of both symbionts prevented insect reproduction. Such findings are likely important for strain divergences reported in the maize weevil and their control, aspects still deserving future attention.</p></div

Summary of the non-linear regression analyses of the cumulative emergence curves (Fig. 5) of the F₁ and F₂ progenies of adult maize weevils (<i>Sitophilus zeamais</i>) exposed to different endosymbiont-suppression treatments via water-ingested antibiotics.

<p>Summary of the non-linear regression analyses of the cumulative emergence curves (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0111396#pone-0111396-g005" target="_blank">Fig. 5</a>) of the F₁ and F₂ progenies of adult maize weevils (<i>Sitophilus zeamais</i>) exposed to different endosymbiont-suppression treatments via water-ingested antibiotics.</p

Load (± SE) of the endosymbionts SZPE (A, C) and <i>Wolbachia</i> (B, D) in F₁ (A, B) and F₂ progenies (C, D) of maize weevils (<i>Sitophilus zeamais</i>) exposed to different endosymbiont-reducing treatments.

<p>Means followed by the same letter in a histogram are not significantly different by Tukey’s HSD test (<i>P</i><0.05).</p

Respiration rate (A, C) and body mass (B, D) (± SE) of F₁ (A, B) and F₂ progenies (C, D) of maize weevils (<i>Sitophilus zeamais</i>) exposed to different endosymbiont-reducing treatments.

<p>Means followed by the same letter in a histogram are not significantly different by Tukey’s HSD test (<i>P</i><0.05).</p

Summary of the non-linear regression analyses of the daily emergence curves (Fig. 5) of the F₁ and F₂ progenies of adult maize weevils (<i>Sitophilus zeamais</i>) exposed to different endosymbiont-suppression treatments via water-ingested antibiotics.

<p>Summary of the non-linear regression analyses of the daily emergence curves (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0111396#pone-0111396-g005" target="_blank">Fig. 5</a>) of the F₁ and F₂ progenies of adult maize weevils (<i>Sitophilus zeamais</i>) exposed to different endosymbiont-suppression treatments via water-ingested antibiotics.</p

Behavioral traits (± SE) of maize weevils (<i>Sitophilus zeamais</i>) exposed to different endosymbiont-reducing treatments.

<p>Behavioral traits (± SE) of maize weevils (<i>Sitophilus zeamais</i>) exposed to different endosymbiont-reducing treatments.</p

Ordination (CVA) diagram showing the divergence in behavioral traits of maize weevils (<i>Sitophilus zeamais</i>) exposed to different endosymbiont-reducing treatments (see Table 2).

<p>Both canonical axes are significant and account for 97.45% of the total variance explained. The solid symbols are centroids of treatments representing the class mean canonical variates and the smaller symbols of the same color represent the individual replicates. The large circles indicate clusters of treatments that are not significantly different by the approximated F-test (<i>P<0.05)</i>, based on the Mahalanobis (D²) distance between class means.</p

Cumulative emergence of F₁ (A) and F₂ progenies (B) of maize weevils (<i>Sitophilus zeamais</i>) exposed to different endosymbiont-reducing treatments.

<p>The symbols and vertical bars represent the means and standard errors of four replicates and the equation parameters are exhibited in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0111396#pone-0111396-t004" target="_blank">Table 4</a>.</p