Vicuña (Vicugna v. mensalis) herds modify their behaviour after being captured and sheared: implications on conservation and management

Póster presentado al Joint meeting of the 33rd International Ethological Conference (IEC) & the Association for the Study of Animal Behaviour (ASAB), celebrado en Newcastle-Gateshead (UK) del 4 al 8 de agosto de 2013.We present here evidence of a modification in foraging and guarding rates in vicuña herds subject to a traditional shearing management in Central Andes, Perú. The study was conducted from March to December 2011. We recorded behaviour of a vicuña population made up of ca. 300 individuals, living in semi-captive conditions and captured once a year for shearing. We registered foraging and guarding rates of adult males and females as well as calves, and distinguished three periods: before being captured, after being captured for marking and after being captured for shearing. Guarding behaviour is predominantly made by males, it is negatively related to group size, and varies according to the habitat and management period, decreasing significantly after shearing. Foraging behaviour rate is higher in females than in males and lambs, and significantly increases for all individuals after capture and shearing, it is positively related to group size. We hypothesize that after shearing vicuñas are prone to increase their daily foraging rate due to energy demands; this affecting their guarding rate and in turn their vulnerability to predators.Thanks to funding obtained in the Fifth Call for Research in Ecology and Conservation Biology from BBVA Foundation (BIOCON08-059).Peer Reviewe

Hidden geometric correlations in real multiplex networks

Real networks often form interacting parts of larger and more complex systems. Examples can be found in different domains, ranging from the Internet to structural and functional brain networks. Here, we show that these multiplex systems are not random combinations of single network layers. Instead, they are organized in specific ways dictated by hidden geometric correlations between the individual layers. We find that these correlations are strong in different real multiplexes, and form a key framework for answering many important questions. Specifically, we show that these geometric correlations facilitate: (i) the definition and detection of multidimensional communities, which are sets of nodes that are simultaneously similar in multiple layers; (ii) accurate trans-layer link prediction, where connections in one layer can be predicted by observing the hidden geometric space of another layer; and (iii) efficient targeted navigation in the multilayer system using only local knowledge, which outperforms navigation in the single layers only if the geometric correlations are sufficiently strong. Our findings uncover fundamental organizing principles behind real multiplexes and can have important applications in diverse domains.Comment: Supplementary Materials available at http://www.nature.com/nphys/journal/v12/n11/extref/nphys3812-s1.pd

Rectal swabs as a viable alternative to faecal sampling for the analysis of gut microbiota functionality and composition

Faecal or biopsy samples are frequently used to analyse the gut microbiota, but issues remain with the provision and collection of such samples. Rectal swabs are widely-utilised in clinical practice and previous data demonstrate their potential role in microbiota analyses; however, studies to date have been heterogenous, and there is a particular lack of data concerning the utility of swabs for the analysis of the microbiota’s functionality and metabolome. We compared paired stool and rectal swab samples from healthy individuals to investigate whether rectal swabs are a reliable proxy for faecal sampling. There were no significant differences in alpha and beta diversity measures between swab and faecal samples, and inter-subject variability was preserved. Additionally, no significant differences were demonstrated in abundance of major annotated phyla. Inferred gut functionality using Tax4Fun2 showed excellent correlation between the two sampling techniques (Pearson’s coefficient r = 0.9217, P  < 0.0001). Proton nuclear magnetic resonance ( 1 H NMR) spectroscopy enabled the detection of 20 metabolites with good correlation between rectal swab and faecal samples for butyrate, succinate and 5-aminovalerate relative abundances, though more variable degrees of association for other identified metabolites. These data support the utility of rectal swabs in both compositional and functional analyses of the gut microbiota

The metabolic interplay between dietary carbohydrate and exercise and its role in acute appetite-regulation in males: a randomised controlled study

Understanding the metabolic determinants of post-exercise appetite-regulation would facilitate the development of adjunctive-therapeutics to supress compensatory eating behaviours and improve the efficacy of exercise as a weight loss treatment. Metabolic responses to acute exercise are however dependent on pre-exercise nutritional practices, including carbohydrate intake. We therefore aimed to determine the interactive effects of dietary carbohydrate and exercise on plasma hormonal and metabolite responses and explore mediators of exercise-induced changes in appetite-regulation across nutritional states. In this randomised crossover study, participants completed four 120 min visits: (i) control (water) followed by rest; (ii) control followed by exercise (30 min at ∼75% V̇O2 max); (iii) carbohydrate (75 g maltodextrin) followed by rest; and (iv) carbohydrate followed by exercise. An ad libitum meal was provided at the end of each 120 min visit, with blood sample collection and appetite assessment performed at pre-defined intervals. We found that dietary carbohydrate and exercise exerted independent effects on the hormones GLP-1 (Carbohydrate: 16.8 pmol/L, Exercise: 7.4 pmol/L), ghrelin (Carbohydrate: -48.8 pmol/L, Exercise: -22.7 pmol/L) and glucagon (Carbohydrate: 9.8 ng/L, Exercise: 8.2 ng/L) that were linked to the generation of distinct plasma 1H-NMR metabolic phenotypes. These metabolic responses were associated with changes in appetite and energy intake, and plasma acetate and succinate were subsequently identified as potential novel mediators of exercise-induced appetite and energy intake responses. In summary, dietary carbohydrate and exercise independently influence gastrointestinal hormones associated with appetite regulation. Future work is warranted to probe the mechanistic importance of plasma acetate and succinate in post-exercise appetite-regulation

RELACIÓN ENTRE LA CONTAMINACIÓN DEL ACEITE CON SÍLICE Y EL DESGASTE DEL MOTOR

La técnica de análisis espectrométrico de aceites de motores de automoción es altamente efectiva para detectar su desgaste. Los resultados de la aplicación de esta técnica son las concentraciones metálicas de los principales metales de desgaste presentes en muestras de aceite usado; en el caso de los motores de vehículos industriales seconsideran aluminio, cromo, cobre, estaño, hierro, níquel, plomo y silicio. El objetivo de la presente ponencia es llevar a cabo una investigación estadística con el objetivo de relacionar el contenido de silicio con los contenidos de metales de desgaste, a partir de los resultados obtenidos del análisis espectrométrico de un elevado número de muestras de aceite usado, tomadas en motores de diferentes vehículos almacenados en una base de datos. Se considera además, la influencia del tipo de servicio, examinando por separado el caso de los motores de vehículos de transporte y el de los de obras públicas

Amphibian skin bacteria display antifungal activity and induce plant defense mechanisms against Botrytis cinerea

Botrytis cinerea is the causal agent of gray mold, which affects a wide variety of plant species. Chemical agents have been used to prevent the disease caused by this pathogenic fungus. However, their toxicity and reduced efficacy have encouraged the development of new biological control alternatives. Recent studies have shown that bacteria isolated from amphibian skin display antifungal activity against plant pathogens. However, the mechanisms by which these bacteria act to reduce the effects of B. cinerea are still unclear. From a diverse collection of amphibian skin bacteria, three proved effective in inhibiting the development of B. cinerea under in vitro conditions. Additionally, the individual application of each bacterium on the model plant Arabidopsis thaliana, Solanum lycopersicum and post-harvest blueberries significantly reduced the disease caused by B. cinerea. To understand the effect of bacteria on the host plant, we analyzed the transcriptomic profile of A. thaliana in the presence of the bacterium C32I and the fungus B. cinerea, revealing transcriptional regulation of defense-related hormonal pathways. Our study shows that bacteria from the amphibian skin can counteract the activity of B. cinerea by regulating the plant transcriptional responses

Programmed cell senescence during mammalian embryonic development

Cellular senescence disables proliferation in damaged cells, and it is relevant for cancer and aging. Here, we show that senescence occurs during mammalian embryonic development at multiple locations, including the mesonephros and the endolymphatic sac of the inner ear, which we have analyzed in detail. Mechanistically, senescence in both structures is strictly dependent on p21, but independent of DNA damage, p53, or other cell-cycle inhibitors, and it is regulated by the TGF-beta/SMAD and PI3K/FOXO pathways. Developmentally programmed senescence is followed by macrophage infiltration, clearance of senescent cells, and tissue remodeling. Loss of senescence due to the absence of p21 is partially compensated by apoptosis but still results in detectable developmental abnormalities. Importantly, the mesonephros and endolymphatic sac of human embryos also show evidence of senescence. We conclude that the role of developmentally programmed senescence is to promote tissue remodeling and propose that this is the evolutionary origin of damage-induced senescence

Integrated fecal microbiome–metabolome signatures reflect stress and serotonin metabolism in irritable bowel syndrome

To gain insight into the complex microbiome-gut-brain axis in irritable bowel syndrome (IBS) several modalities of biological and clinical data must be combined. We aimed to identify profiles of faecal microbiota and metabolites associated with IBS and to delineate specific phenotypes of IBS that represent potential pathophysiological mechanisms. Faecal metabolites were measured using proton Nuclear Magnetic Resonance (1H-NMR) spectroscopy and gut microbiome using Shotgun Metagenomic Sequencing (MGS) in a combined dataset of 142 IBS patients and 120 healthy controls (HC) with extensive clinical, biological and phenotype information. Data were analysed using support vector classification and regression and kernel t-SNE. Microbiome and metabolome profiles could distinguish IBS and HC with an area-under-the-receiver-operator-curve (AUC) of 77.3% and 79.5%, respectively, but this could be improved by combining microbiota and metabolites to 83.6%. No significant differences in predictive ability of the microbiome-metabolome data were observed between the three classical, stool pattern-based, IBS subtypes. However, unsupervised clustering showed distinct subsets of IBS patients based on faecal microbiome-metabolome data. These clusters could be related plasma levels of serotonin and its metabolite 5-hydroxyindoleacetate, effects of psychological stress on gastrointestinal symptoms, onset of IBS after stressful events, medical history of previous abdominal surgery, dietary caloric intake and IBS symptom duration. Furthermore, pathways in metabolic reaction networks were integrated with microbiota data, that reflect the host-microbiome interactions in IBS. The identified microbiome-metabolome signatures for IBS, associated with altered serotonin metabolism and unfavourable stress-response related to gastrointestinal symptoms, support the microbiota-gut-brain link in the pathogenesis of IBS