Division of labor in insect societies : genetic components and physiological regulation

The shift from solitary to social organisms constitutes one of the major transitions in evolution. The highest level of sociality is found in social insects (ants, termites and some species of bees and wasps). Division of labor is central to the organization of insect societies and is thought to be at the root of their ecological success. There are two main levels of division of labor in social insect colonies. The first relates to reproduction and involves the coexistence of queen and worker castes: while reproduction is usually monopolized by one or several queens, functionally sterile workers perform all the tasks to maintain the colony, such as nest building, foraging or brood care. The second level of division of labor, relating to such non-reproductive duties, is characterized by the performance of different tasks or roles by different groups of workers. This PhD aims to better understand the mechanisms underlying division of labor in insect societies, by investigating how genes and physiology influence caste determination and worker behavior in ants. In the first axis of this PhD, we studied the nature of genetic effects on division of labor. We used the Argentine ant Linepithema humile to conduct controlled crosses in the laboratory, which revealed the existence of non-additive genetic effects, such as parent-of-origin and genetic compatibility effects, on caste determination and worker behavior. In the second axis, we focused on the physiological regulation of division of labor. Using Pogonomyrmex seed- harvester ants, we performed experimental manipulation of hibernation, hormonal treatments, gene expression analyses and protein quantification to identify the physiological pathways regulating maternal effects on caste determination. Finally, comparing gene expression between nurses and foragers allowed us to reveal the association between vitellogenin and worker behavior in Pogonomyrmex ants. This PhD provides important insights into the role of genes and physiology in the regulation of division of labor in social insect colonies, helping to better understand the organization, evolution and ecological success of insect societies. - L'une des principales transitions évolutives est le passage de la vie solitaire à la vie sociale. La socialité atteint son paroxysme chez les insectes sociaux que sont les fourmis, les termites et certaines espèces d'abeilles et de guêpes. La division du travail est la clé de voûte de l'organisation de ces sociétés d'insectes et la raison principale de leur succès écologique. La division du travail s'effectue à deux niveaux dans les colonies d'insectes sociaux. Le premier niveau concerne la reproduction et implique la coexistence de deux castes : les reines et les ouvrières. Tandis que la reproduction est le plus souvent monopolisée par une ou plusieurs reines, les ouvrières stériles effectuent les tâches nécessaires au bon fonctionnement de la colonie, telles que la construction du nid, la recherche de nourriture ou le soin au couvain. Le second niveau de division du travail, qui concerne les tâches autres que la reproduction, implique la réalisation de différents travaux par différents groupes d'ouvrières. Le but de ce doctorat est de mieux comprendre les mécanismes sous-jacents de la division du travail dans les sociétés d'insectes en étudiant comment les gènes et la physiologie influencent la détermination de la caste et le comportement des ouvrières chez les fourmis. Dans le premier axe de ce doctorat, nous avons étudié la nature des influences génétiques sur la division du travail. Nous avons utilisé la fourmi d'Argentine, Linepithema humile, pour effectuer des croisements contrôlés en laboratoire. Cette méthode nous a permis de révéler l'existence d'influences génétiques non additives, telles que des influences dépendantes de l'origine parentale ou des effets de compatibilité génétique, sur la détermination de la caste et le comportement des ouvrières. Dans le second axe, nous nous sommes intéressés à la régulation physiologique de la division du travail. Nous avons utilisé des fourmis moissonneuses du genre Pogonomyrmex pour effectuer des hibernations artificieHes, des traitements hormonaux, des analyses d'expression de gènes et des mesures de vitellogénine, ce qui nous a permis d'identifier les mécanismes physiologiques régulant les effets maternels sur la détermination de la caste. Enfin, la comparaison d'expression de gènes entre nourrices et fourrageuses suggère un rôle de la vitellogénine dans la régulation du comportement des ouvrières chez les fourmis moissonneuses. En détaillant les influences des gènes et de la physiologie dans la régulation de la division du travail dans les colonies d'insectes sociaux, ce doctorat fournit d'importantes informations permettant de mieux comprendre l'organisation, l'évolution et le succès écologique des sociétés d'insectes.

Arabidopsis Basic Helix-Loop-Helix Transcription Factors MYC2, MYC3, and MYC4 Regulate Glucosinolate Biosynthesis, Insect Performance, and Feeding Behavior.

Arabidopsis thaliana plants fend off insect attack by constitutive and inducible production of toxic metabolites, such as glucosinolates (GSs). A triple mutant lacking MYC2, MYC3, and MYC4, three basic helix-loop-helix transcription factors that are known to additively control jasmonate-related defense responses, was shown to have a highly reduced expression of GS biosynthesis genes. The myc2 myc3 myc4 (myc234) triple mutant was almost completely devoid of GS and was extremely susceptible to the generalist herbivore Spodoptera littoralis. On the contrary, the specialist Pieris brassicae was unaffected by the presence of GS and preferred to feed on wild-type plants. In addition, lack of GS in myc234 drastically modified S. littoralis feeding behavior. Surprisingly, the expression of MYB factors known to regulate GS biosynthesis genes was not altered in myc234, suggesting that MYC2/MYC3/MYC4 are necessary for direct transcriptional activation of GS biosynthesis genes. To support this, chromatin immunoprecipitation analysis showed that MYC2 binds directly to the promoter of several GS biosynthesis genes in vivo. Furthermore, yeast two-hybrid and pull-down experiments indicated that MYC2/MYC3/MYC4 interact directly with GS-related MYBs. This specific MYC-MYB interaction plays a crucial role in the regulation of defense secondary metabolite production and underlines the importance of GS in shaping plant interactions with adapted and nonadapted herbivores.

Population genetics of Capercaillie (Tetrao urogallus) in the Jura and the Pyrenees: a non-invasive approach to avian conservation genetics

RÉSUMÉ Le Grand tétras est un galliforme de montagne apparenté au faisan et au tétras lyre. Il est distribué de manière continue à travers la toundra et les montagnes de moyenne altitude en Europe de l'ouest. Toutefois, les populations d'Europe de l'ouest ont subi un déclin constant au cours des derniers siècles. Les causes de ce déclin sont probablement liées à l'activité humaine, telle .que l'élevage ou le tourisme, qui ont engendré une modification et une fragmentation de l'habitat de l'espèce. Malheureusement, les populations soumises à de forts déclins démographiques peuvent subir des effets génétiques (augmentation de la consanguinité et perte de diversité génétique) pouvant diminuer leur potentiel de reproduction et conduire irrémédiablement à l'extinction. Cette thèse présente les analyses conduites dans le but d'estimer l'impact du déclin démographique des populations de Grand tétras sur l'étendue et la distribution de leur variabilité génétique dans le Jura et dans les Pyrénées. Du fait de la législation locale protégeant les tétraonidés en général, mais également en raison de la biologie très cryptique du Grand tétras, l'ensemble des analyses de cette étude a été réalisé à partir de matériel génétique extrait des fientes (ou échantillonnage génétique non invasif). Dans la première partie de l'étude, je détaille les protocoles d'extraction. d'ADN et d'amplification par PCR modifiés à partir des protocoles classiques utilisant des échantillons conventionnels, riches en ADN. L'utilisation d'ADN fécal impose des contraintes dues à la mauvaise qualité et à la faible quantité du matériel génétique à disposition dans les fientes. Ces contraintes ont pu être partiellement contournées en réalisant des répétitions multiples du génotypage afin d'obtenir un degré de fiabilité suffisante. J'ai également analysé les causes de la dégradation de l'ADN dans les excréments. Parmi les causes les plus communes, telles que l'activité bactérienne, l'hydrolyse spontanée et la dégradation enzymatique par les DNases libres, c'est ce dernier facteur qui apparaît comme étant la cause majeure et la plus rapide responsable de la dégradation de la qualité des échantillons. La rapidité de l'action enzymatique suggère que les plans d'échantillonnages de excréments sur le terrain pourraient être optimisés en les réalisant dans des conditions climatiques froides et sèches, favorisant ainsi l'inhibition des DNases. La seconde partie de la thèse est une étude par simulation visant à déterminer la capacité du logiciel Structure à identifier les structures génétiques complexes et hiérarchiques fréquemment rencontrées dans les populations naturelles, et ce en utilisant différents types de marqueurs génétiques. Les troisième et quatrième parties de cette thèse décrivent le statut génétique des populations résiduelles du Jura et des Pyrénées à partir de l'analyse de 11 loci microsatellites. Nous n'avons pas pu mettre en évidence dans les deux populations des effets liés à la consanguinité ou à la réduction de la diversité génétique. De plus, la différenciation génétique entre les patches d'habitats favorables reste modérée et corrélée à la distance géographique, ce qui suggère que la dispersion d'individus entre les patches a été importante au moins pendant ces dernières générations. La comparaison des paramètres de la diversité génétique avec ceux d'autres populations de Grand tétras, ou d'autres espèces proches, indique que la population du Jura a retenu une proportion importante de sa diversité originelle. Ces résultats suggèrent que le déclin récent des populations a jusqu'ici eu un impact modéré sur les facteurs génétiques et que ces populations semblent avoir conservé le potentiel génétique nécessaire à leur survie à long terme. Finalement, en cinquième partie, l'analyse de l'apparentement entre les mâles qui participent à la parade sur les places de chant (leks) indique que ces derniers sont distribués en agrégats de manière non aléatoire, préférentiellement entre individus apparentés. De plus, la corrélation entre les distances génétique et géographique entre les leks est en accord avec les motifs d'isolement par la distance mis en évidence à d'autres niveaux hiérarchiques (entre patches d'habitat et populations), ainsi qu'avec les études menées sur d'autres espèces ayant choisi ce même système de reproduction. En conclusion, cette première étude basée uniquement sur de l'ADN nucléaire aviaire extrait à partir de fèces a fourni des informations nouvelles qui n'auraient pas pu être obtenues par une méthode d'observation sur le terrain ou d'échantillonnage génétique classique. Aucun oiseau n'a été dérangé ou capturé, et les résultats sont comparables à d'autres études concernant des espèces proches. Néanmoins, la taille de ces populations approche des niveaux au-dessous desquels la survie à long terme est fortement incertaine. La persistance de la diversité génétique pour les prochaines générations reste en conséquence liée à la survie des adultes et à une reprise du succès de la reproduction. ABSTRACT Capercaillie (Tetrao urogallus) is a large grouse that is continuously distributed across the tundra and the mid-high mountains of Western Europe. However, the populations in Western Europe have been showing a constant decline during the last decades. The causes for this decline are possibly related to human activities, such as cattle breeding and tourism that have both led to habitat modification and fragmentation. Unfortunately, populations that have undergone drastic demographic bottlenecks often go through genetic processes of inbreeding and loss of diversity that decrease their fitness and eventually lead to extinction. This thesis presents the investigations conducted to estimate the impact of the demographic decline of capercaillie populations on the extent and distribution of their genetic variability in the Jura and in the Pyrenees mountains. Because grouse are protected by wildlife legislation, and also because of the cryptic behaviour of capercaillie, all DNA material used in this study was extracted from faeces (non-invasive genetic sampling). In the first part of my thesis, I detail the protocols of DNA extraction and PCR amplification adapted from classical methods using conventional DNA-rich samples. The use of faecal DNA imposes specific constraints due to the low quantity and the highly degraded genetic material available. These constraints are partially overcome by performing multiple genotyping repetitions to obtain sufficient reliability. I also investigate the causes of DNA degradation in faeces. Among the main degraders, namely bacterial activity, spontaneous hydrolysis, and free-¬DNase activities, the latter was pointed out as the most important according to our experiments. These enzymes degrade DNA very rapidly, and, as a consequence, faeces sampling schemes must be planned preferably in cold and dry weather conditions, allowing for enzyme activity inhibition. The second part of the thesis is a simulation study aiming to assess the capacity of the software Structure to detect population structure in hierarchical models relevant to situations encountered in wild populations, using several genetic markers. The methods implemented in Structure appear efficient in detecting the highest hierarchical structure. The third and fourth parts of the thesis describe the population genetics status of the remaining Jura and Pyrenees populations using 11 microsatellite loci. In either of these populations, no inbreeding nor reduced genetic diversity was detected. Furthermore, the genetic differentiation between patches defined by habitat suitability remains moderate and correlated with geographical distance, suggesting that significant dispersion between patches was at work at least until the last generations. The comparison of diversity indicators with other species or other populations of capercaillie indicate that population in the Jura has retained a large part of its original genetic diversity. These results suggest that the recent decline has had so forth a moderate impact on• genetic factors and that these populations might have retained the potential for long term survival, if the decline is stopped. Finally, in the fifth part, the analysis of relatedness between males participating in the reproduction parade, or lek, indicate that capercaillie males, like has been shown for some other grouse species, gather on leks• among individuals that are more related than the average of the population. This pattern appears to be due to both population structure and kin-association. As a conclusion, this first study relying exclusively on nuclear DNA extracted from faeces has provided novel information that was not available through field observation or classical genetic sampling. No bird has been captured or disturbed, and the results are consistent with other studies of closely related species. However, the size of these populations is approaching thresholds below which long-term survival is unlikely. The persistence of genetic diversity for the forthcoming generations remains therefore bond to adult survival and to the increase of reproduction success.

Approaching invasive species in Madagascar

While a number of plants, animals, and insects in Madagascar have been called 'invasive', the topic of invasive species has until recently received less attention here than in other island contexts. Some species, often alien to Madagascar and introduced by humans, have expanded their range rapidly and have had both negative and positive effects on landscapes, on native biodiversity, and on livelihoods. Examples include the prickly pear (raketa), the silver wattle (mimosa), and, recently, the Asian common toad (radaka boka). Building on a conceptual approach to 'invasive species', this paper emphasizes the importance of inclusive and deliberative site- and population - specific management of invasive species. It analyses three separate concepts commonly used in definitions of invasion: the origin, behaviour, and effects of particular species. It places these concepts in their broader social and ecological context, with particular attention to local perspectives on invasive species. We illustrate these concepts with Malagasy examples and data. The examples demonstrate that while invasions can have dramatic consequences, there can be multiple, often competing, interests as well as site - specific biophysical, environmental, and cultural considerations that need to be taken into account when designing policy and management interventions. We conclude with a number of lessons learned. RESUME FRANCAIS Contrairement à la plupart des autres îles, et en dépit du qualificatif 'invasif' rattaché depuis longtemps à certaines espèces qui s'y sont naturalisées, les réflexions autour de l'approche des espèces invasives à Madagascar demeurent récentes. L'opuntia (Opuntia spp.) figure certes parmi les plus anciens exemples d'espèces traités dans la littérature sur les invasions biologiques. Mais ce n'est vraiment qu'avec le retentissement médiatique autour de la détection en 2011 de la présence du crapaud masqué (Duttaphrynus melanostictus) et la recherche d'une parade appropriée que s'est affirmée la nécessité de traiter cette question des espèces invasives en tant que telle. Une posture nativiste et uniforme qui ignorerait la spécificité des contextes biophysiques et socio - économiques locaux, mais aussi la pluralité des formes d'invasion biologique et des défi- nitions qui s'y rattachent, ne saurait être privilégiée. L'article montre qu'il s'agit de situer les réflexions dans un contexte insulaire socio - économique dans lequel les espèces allogènes tiennent depuis longtemps une large place. Il défend en outre la nécessité d'envisager les espèces invasives non pas selon une forme de perception unique et autoritariste, mais selon une diversité de points de vue, conforme aux conflits d'intérêts qui se manifestent parfois, et mettant plutôt en avant le caractère exogène des espèces invasives, leurs effets (négatifs, mais aussi positifs) sur le milieu, ou leur mode de fonctionnement (disper- sion, dominance) dans des contextes spécifiques et locaux. Il convient en particulier d'observer qu'aux coûts générés par les invasions biologiques peuvent s'ajouter des bénéfices économiques, et que les impacts écologiques néfastes peuvent se combiner avec des incidences heureuses, y compris auprès d'espèces indigènes en situation critique. En outre, le point de vue des populations humaines, leur connaissance d'espèces invasives quotidiennement rencontrées, leur réticence à scin- der le vivant en espèces indigènes et allogène, mais aussi leur vision pragmatique, ne sauraient être mésestimés, et moins encore oubliés. Enfin, l'article invite à prendre du recul face aux effets rhétoriques liés aux discours conventionnels sur les inva- sions biologiques, à éviter les amalgames et les généralisations excessives, à tenir compte des contraintes environnementales mais aussi des aspirations socio - économiques des populations locales, et à prendre en compte la diversité des spécificités locales, qu'elles soient biophysiques ou sociales. En conclusion, il est sans doute heureux que Madagascar n'ait rejoint que très récemment la mouvance internationale des réflexions sur les espèces invasives : cela lui permet en effet d'être en mesure de disposer d'une position équilibrée, déjouant certains discours catastrophistes, et préférant une approche résolument contextualisée, à l'échelle nationale comme aux échelles régionales.

IL1B and DEFB1 Polymorphisms Increase Susceptibility to Invasive Mold Infection After Solid-Organ Transplantation.

BACKGROUND: Single-nucleotide polymorphisms (SNPs) in immune genes have been associated with susceptibility to invasive mold infection (IMI) among hematopoietic stem cell but not solid-organ transplant (SOT) recipients. METHODS: Twenty-four SNPs from systematically selected genes were genotyped among 1101 SOT recipients (715 kidney transplant recipients, 190 liver transplant recipients, 102 lung transplant recipients, 79 heart transplant recipients, and 15 recipients of other transplants) from the Swiss Transplant Cohort Study. Association between SNPs and the end point were assessed by log-rank test and Cox regression models. Cytokine production upon Aspergillus stimulation was measured by enzyme-linked immunosorbent assay in peripheral blood mononuclear cells (PBMCs) from healthy volunteers and correlated with relevant genotypes. RESULTS: Mold colonization (n = 45) and proven/probable IMI (n = 26) were associated with polymorphisms in the genes encoding interleukin 1β (IL1B; rs16944; recessive mode, P = .001 for colonization and P = .00005 for IMI, by the log-rank test), interleukin 1 receptor antagonist (IL1RN; rs419598; P = .01 and P = .02, respectively), and β-defensin 1 (DEFB1; rs1800972; P = .001 and P = .0002, respectively). The associations with IL1B and DEFB1 remained significant in a multivariate regression model (P = .002 for IL1B rs16944; P = .01 for DEFB1 rs1800972). The presence of 2 copies of the rare allele of rs16944 or rs419598 was associated with reduced Aspergillus-induced interleukin 1β and tumor necrosis factor α secretion by PBMCs. CONCLUSIONS: Functional polymorphisms in IL1B and DEFB1 influence susceptibility to mold infection in SOT recipients. This observation may contribute to individual risk stratification.

Preventing invasive candida infections. Where could we do better?

Invasive candidiasis is associated with high mortality rates, ranging from 35% to 60%, in the range reported for septic shock. The epidemiology and pathogenesis of invasive candidiasis differ according to the patient's immune status; the majority of cases in immunocompromised hosts are candidaemia, whereas non-candidaemic systemic candidiasis accounts for the majority of cases in critically ill patients. In contrast to candidaemia, non-candidaemic systemic candidiasis is difficult to prove, especially in critically ill patients. Up to 80% of these patients are colonized, but only 5-30% develop invasive infection. The differentiation of colonization and proven infection is challenging, and evolution from the former to the latter requires seven to 10 days. This continuum from colonization of mucosal surfaces to local invasion and then invasive infection makes it difficult to identify those critically ill patients likely to benefit most from antifungal prophylaxis or early empirical antifungal treatment. Early empirical treatment of non-candidaemic systemic candidiasis currently relies on the positive predictive value of risk assessment strategies, such as the colonization index, candida score, and predictive rules based on combinations of risk factors such as candida colonization, broad-spectrum antibiotics, and abdominal surgery. Although guidelines recently scored these strategies as being supported by limited evidence, they are widely used at bedside and have substantially decreased the incidence of invasive candidiasis.

Outcomes of minimally invasive simple prostatectomy for benign prostatic hyperplasia: a systematic review and meta-analysis.

PURPOSE: (1) To assess the outcomes of minimally invasive simple prostatectomy (MISP) for the treatment of symptomatic benign prostatic hyperplasia in men with large prostates and (2) to compare them with open simple prostatectomy (OSP). METHODS: A systematic review of outcomes of MISP for benign prostatic hyperplasia with meta-analysis was conducted. The article selection process was conducted according to the PRISMA guidelines. RESULTS: Twenty-seven observational studies with 764 patients were analyzed. The mean prostate volume was 113.5 ml (95 % CI 106-121). The mean increase in Qmax was 14.3 ml/s (95 % CI 13.1-15.6), and the mean improvement in IPSS was 17.2 (95 % CI 15.2-19.2). Mean duration of operation was 141 min (95 % CI 124-159), and the mean intraoperative blood loss was 284 ml (95 % CI 243-325). One hundred and four patients (13.6 %) developed a surgical complication. In comparative studies, length of hospital stay (WMD -1.6 days, p = 0.02), length of catheter use (WMD -1.3 days, p = 0.04) and estimated blood loss (WMD -187 ml, p = 0.015) were significantly lower in the MISP group, while the duration of operation was longer than in OSP (WMD 37.8 min, p < 0.0001). There were no differences in improvements in Qmax, IPSS and perioperative complications between both procedures. The small study sizes, publication bias, lack of systematic complication reporting and short follow-up are limitations. CONCLUSIONS: MISP seems an effective and safe treatment option. It provides similar improvements in Qmax and IPSS as OSP. Despite taking longer, it results in less blood loss and shorter hospital stay. Prospective randomized studies comparing OSP, MISP and laser enucleation are needed to define the standard surgical treatment for large prostates.

Transanal minimal invasive surgery for rectal lesions: should the defect be closed?

AIM: Transanal minimal invasive surgery (TAMIS) of rectal lesions is increasingly being used, but the technique is not yet standardized. The aims of this study were to evaluate peri-operative complications and long-term functional outcome of the technique and to analyse whether or not the rectal defect needs to be closed. METHOD: Consecutive patients undergoing TAMIS using the SILS port (Covidien) and standard laparoscopic instruments were studied. RESULTS: Seventy-five patients (68% male) of mean age 67 (± 15) years underwent single-port transanal surgery at three different centres for 37 benign lesions and 38 low-risk cancers located at a mean of 6.4 ± 2.3 cm from the anal verge. The median operating time was 77 (25-245) min including a median time for resection of 36 (15-75) min and for closure of the rectal defect of 38 (9-105) min. The defect was closed in 53% using interrupted (75%) or a running suture (25%). Intra-operative complications occurred in six (8%) patients and postoperative morbidity was 19% with only one patient requiring reoperation for Grade IIIb local infection. There was no difference in the incidence of complications whether the rectal defect was closed or left open. Patients were discharged after 3.4 (1-21) days. At a median follow-up of 12.8 (2-29) months, the continence was normal (Vaizey score of 1.5; 0-16). CONCLUSION: Transanal rectal resection can be safely and efficiently performed by means of a SILS port and standard laparoscopic instruments. The rectal defect may be left open and at 1 year continence is not compromised.

End-tidal carbon dioxide monitoring using a naso-buccal sensor is not appropriate to monitor capnia during non-invasive ventilation.

BACKGROUND: In acute respiratory failure, arterial blood gas analysis (ABG) is used to diagnose hypercapnia. Once non-invasive ventilation (NIV) is initiated, ABG should at least be repeated within 1 h to assess PaCO2 response to treatment in order to help detect NIV failure. The main aim of this study was to assess whether measuring end-tidal CO2 (EtCO2) with a dedicated naso-buccal sensor during NIV could predict PaCO2 variation and/or PaCO2 absolute values. The additional aim was to assess whether active or passive prolonged expiratory maneuvers could improve the agreement between expiratory CO2 and PaCO2. METHODS: This is a prospective study in adult patients suffering from acute hypercapnic respiratory failure (PaCO2 ≥ 45 mmHg) treated with NIV. EtCO2 and expiratory CO2 values during active and passive expiratory maneuvers were measured using a dedicated naso-buccal sensor and compared to concomitant PaCO2 values. The agreement between two consecutive values of EtCO2 (delta EtCO2) and two consecutive values of PaCO2 (delta PaCO2) and between PaCO2 and concomitant expiratory CO2 values was assessed using the Bland and Altman method adjusted for the effects of repeated measurements. RESULTS: Fifty-four datasets from a population of 11 patients (8 COPD and 3 non-COPD patients), were included in the analysis. PaCO2 values ranged from 39 to 80 mmHg, and EtCO2 from 12 to 68 mmHg. In the observed agreement between delta EtCO2 and deltaPaCO2, bias was -0.3 mmHg, and limits of agreement were -17.8 and 17.2 mmHg. In agreement between PaCO2 and EtCO2, bias was 14.7 mmHg, and limits of agreement were -6.6 and 36.1 mmHg. Adding active and passive expiration maneuvers did not improve PaCO2 prediction. CONCLUSIONS: During NIV delivered for acute hypercapnic respiratory failure, measuring EtCO2 using a dedicating naso-buccal sensor was inaccurate to predict both PaCO2 and PaCO2 variations over time. Active and passive expiration maneuvers did not improve PaCO2 prediction. TRIAL REGISTRATION: ClinicalTrials.gov: NCT01489150.

Toxicity of allyl esters in insect cell lines and in Spodoptera littoralis larvae

We investigated the effects of five allyl esters, two aromatic (allyl cinnamate and allyl 2-furoate) and three aliphatic (allyl hexanoate, allyl heptanoate, and allyl octanoate) in established insect cell lines derived from different species and tissues. We studied embryonic cells of the fruit fly Drosophila melanogaster (S2) (Diptera) and the beet armyworm Spodoptera exigua (Se4) (Lepidoptera), fat body cells of the Colorado potato beetle Leptinotarsa decemlineata (CPB) (Coleoptera), ovarian cells of the silkmoth Bombyx mori (Bm5), and midgut cells of the spruce budworm Choristoneura fumiferana (CF203) (Lepidoptera). Cytotoxicity was determined with use of MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide] and trypan blue. In addition, we tested the entomotoxic action of allyl cinnamate against the cotton leafworm Spodoptera littoralis .The median (50%) cytotoxic concentrations (EC50s) of the five allyl esters in the MTT bioassays ranged between 0.25 and 27 mM with significant differences among allyl esters (P = 0.0012), cell lines (P < 0.0001), and the allyl estercell line interaction (P < 0.0001). Allyl cinnamate was the most active product, and CF203 the most sensitive cell line. In the trypan blue bioassays, cytotoxicity was produced rapidly and followed the same trend observed in the MTT bioassay. In first instars of S. littoralis, allyl cinnamate killed all larvae at 0.25% in the diet after 1 day, while this happened in third instars after 5 days. The LC50 in first instars was 0.08%. In addition, larval weight gain was reduced (P < 0.05) after 1 day of feeding on diet with 0.05%. In conclusion, the data provide evidence of the significant but differential cytotoxicity among allyl esters in insect cells of different species and tissues. Midgut cells show high sensitivity, indicating the insect midgut as a primary target tissue. Allyl cinnamate caused rapid toxic effects in S. littoralis larvae at low concentrations, suggesting further potential for use in pest control.

What is the potential of spread in invasive bryophytes?

Although the number of invasive bryophytes is much lower than that of higher plants, they threaten habitats that are often species rich and of high conservation relevance. Their potential of spread has, however, never been determined. Here, we assess whether the three most invasive bryophyte species shifted their niche during the invasion process and whether the extent of the study area defined to calibrate the model (geographic background, GB) affects model transferability. We then determine whether ecological niche models (ENMs) developed in their native range can be projected in other areas to assess their invasive potential. The macroclimatic niches of Campylopus introflexus, Orthodontium lineare and Lophocolea semiteres were compared in their native range (Southern Hemisphere) and in their invasion range (Northern Hemisphere) using ordination techniques. ENMs from an ensemble model were calibrated in the native range and projected onto the Northern Hemisphere using different GBs. No evidence for niche expansion in the invaded range was found and the species occur in the invaded range under climate conditions that are similar to those in the native range. The performance of the models to predict occurrences in the invaded range increased with the extent of the GB. The potential range of all species included entire regions on continents where they are still absent. The expansion of the investigated species appears to be constrained by climate conditions that are similar to those currently prevailing in their native range, which is consistent with our failure to demonstrate macroclimatic niche shift in the invaded range. The use of large GBs is recommended in such vagile organisms with large, disjunct distributions. The models indicated that invasive bryophyte species might become a threat in central and eastern Europe, North America and eastern Asia if accidentally introduced or naturally dispersed.

PTX3 Polymorphisms and Invasive Mold Infections After Solid Organ Transplant.

Donor PTX3 polymorphisms were shown to influence the risk of invasive aspergillosis among hematopoietic stem cell transplant recipients. Here, we show that PTX3 polymorphisms are independent risk factors for invasive mold infections among 1101 solid organ transplant recipients, thereby strengthening their role in mold infection pathogenesis and patients' risk stratification.

Discovery-dominance trade-off among widespread invasive ant species

Ants are among the most problematic invasive species. They displace numerous native species, alter ecosystem processes, and can have negative impacts on agriculture and human health. In part, their success might stem from a departure from the discovery-dominance trade-off that can promote co-existence in native ant communities, that is, invasive ants are thought to be at the same time behaviorally dominant and faster discoverers of resources, compared to native species. However, it has not yet been tested whether similar asymmetries in behavioral dominance, exploration, and recruitment abilities also exist among invasive species. Here, we establish a dominance hierarchy among four of the most problematic invasive ants (Linepithema humile, Lasius neglectus, Wasmannia auropunctata, Pheidole megacephala) that may be able to arrive and establish in the same areas in the future. To assess behavioral dominance, we used confrontation experiments, testing the aggressiveness in individual and group interactions between all species pairs. In addition, to compare discovery efficiency, we tested the species' capacity to locate a food resource in a maze, and the capacity to recruit nestmates to exploit a food resource. The four species differed greatly in their capacity to discover resources and to recruit nestmates and to dominate the other species. Our results are consistent with a discovery-dominance trade-off. The species that showed the highest level of interspecific aggressiveness and dominance during dyadic interactions.

The potential of different fruit species as food for Harmonia axyridis (Pallas, 1773) (Coleoptera: Coccinellidae)

Harmonia axyridis was detected for the first time in Brazil in 2002. Since then, it has been recorded from the South to the Midwest of the country. Until now, almost all the registered cases were associated with the presence of aphids, its preferred source of food. Due to the occurrence of this species in areas of fruit growing in the South and Southeast of Brazil, the aim of this study was to analyze the preference and use of three different cultivars of fruit. The tests were set at 25ºC ± 1ºC, RH 70% ± 10%, and in a photophase of 12 h and with apples (Gala and Fuji), grapes (Niágara and Rubi), and pears (Williams and Asian). In the undamaged fruit experiment, the insects did not cause any noticeable damage. In the damaged and undamaged fruit experiment, a higher and statistically significant percentage of H. axyridis adults were found in the three damaged fruits. In the different cultivar experiment the Niágara grape, the Gala apple, and the Williams pear were significantly preferred by H. axyridis adults. These results may help in the management of this insect, preventing damage, which have been observed in other places where H. axyridis was introduced.