Trophic ecology of the Endangered Darwin's frog inferred by stable isotopes

Indexación: Scopus.Acknowledgements. We thank Dr. Mauricio González-Chang for his contribution to invertebrate identification and Sally Wren for the revision of an earlier version of the manuscript. We are also extremely grateful to Tomás Elgueta Alvarez for providing Video S1. B.E.M.B. has a fellowship awarded by Universidad Andres Bello. This research project was approved by the Bioethics Committee at the Universi-dad Andres Bello, Chile (N°13/2015), and by permits N°5666/2013, N°230/2015, and N°212/2016 of the Chilean Agriculture and Livestock Service, and N°026/2013 and N°11/2015 IX of the Chilean National Forestry Corporation. This study was funded by the Dirección General de Investi-gación y Doctorados, Universidad Andres Bello, through grant N°DI-53-11/R and national funds through FONDE CYT N°11140902 and 1181758 (to C.S.A.).Darwin's frogs Rhinoderma spp. are the only known mouth-brooding frogs on Earth. The southern Darwin's frog, R. darwinii, is found in the temperate forests of southern South America, is listed as Endangered and could be the only extant representative of this genus. Based on stomach contents, invertebrate prey availability and stable isotope analysis, we determined for the first time trophic ecological parameters for this species. Our results showed that R. darwinii is a generalist sit-and-wait predator and a secondary consumer, with a trophic position of 2.9. Carbon and nitrogen isotope composition indicated that herbivore invertebrates are their main prey, detected in 68.1% of their assimilated food. The most consumed prey included mosquitoes, flies, crickets, grasshoppers and ants. Detritivore and carnivore invertebrates were also ingested, but in lower proportions. Our results contribute to a better understanding of the feeding habits of this fully terrestrial amphibian and provide the first insight into their role linking low forest trophic positions with intermediate predators. We provide valuable biological information for in situ and ex situ conservation which can be used when developing habitat protection, reintroduction and captive breeding programmes. As revealed here, stable isotope analysis is a valuable tool to study the trophic ecology of highly endangered and cryptic species. © The authors 2018.https://www.int-res.com/abstracts/esr/v36/p269-278

Analysis of the Influence of the Molecular Volume to Predict Experimental Pressure-Temperature Behavior in the Isotropic-Nematic Phase Transition of PAP, 5CB, MBBA and EBBA

In this work, we have analyzed the experimental pressure-temperature behavior at the isotropic-nematic phase transition of the liquid crystals PAP, 5CB, MBBA, and EBBA at 1 atm by using the HERSW Convex Peg model in conjunction with the IPCM model. We have calculated the molecular volume values for the hard and attractive cores from theoretical quantum calculations at the PM3, PM6, B3LYP/6-311++G(d,p)//PM6, and M06/6-311++G(d,p)//PM6 levels of theory. The results suggest that the best theoretical prediction of the experimental pressure-temperature behavior is obtained when the molecular volume is evaluated at the DFT level.En este trabajo, nosotros analizamos el comportamiento experimental presión-temperatura pa la fase de transición Isotrópica-nemática de los cristales líquidos PAP, 5CB, MBBA, y EBBA a 1 atm usando el modelo HERSW Convex Peg en conjunto con el modelo IPCM. Nosotros calculamos el valor del volumen molecular y cálculos teóricos para los niveles PM3, PM6, B3LyP/6-311++G(d,p)//PM& y M06/6-311++(d,p)//PM6. Los resultados sugieren que la mejor predicción del comportamiento experimental presión-temperatura es obtenido cuando el volumen molecular es evaluado para el nivel DFT

Synthesis of Batrachochytrium dendrobatidis infection in South America: amphibian species under risk and areas to focus research and disease mitigation

Amphibian chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), has been recognized as the infectious disease causing the most catastrophic loss of biodiversity known to science, with South America being the most impacted region. We tested whether Bd prevalence is distributed among host taxonomy, ecoregion, conservation status and habitat preference in South America. Here we provide a synthesis on the extent of Bd infection across South America based on 21 648 molecular diagnostic assays, roles of certain species in the epidemiology of Bd and explore its association with the reported amphibian catastrophic declines in the region. We show that Bd is widespread, with a continental prevalence of 23.2%. Its occurrence in the region shows a phylogenetic signal and the probability of infection is determined by ecoregion, preferred habitat and extinction risk hosts' traits. The taxa exhibiting highest Bd occurrence were mostly aquatic amphibians, including Ranidae, Telmatobiidae, Hylodidae, Calyptocephalellidae and Pipidae. Surprisingly, families exhibiting unusually low Bd prevalence included species in which lethal chytridiomycosis and population declines have been described (genera Atelopus, Rhinoderma and Eleutherodactylus). Higher than expected prevalence of Bd occurred mainly in amphibians living in association with mountain environments in the Andes and Atlantic forests, reflecting highly favourable Bd habitats in these areas. Invasive amphibian species (e.g. Lithobates catesbeianus and Xenopus laevis) exhibited high Bd prevalence; thus we suggest using these as sentinels to understand their potential role as reservoirs, vectors or spreaders of Bd that can be subjected to management. Our results guide on the prioritization of conservation actions to prevent further biodiversity loss due to chytridiomycosis in the world's most amphibian diverse region

Chytridiomycosis outbreak in a Chilean giant frog (Calyptocephalella gayi) captive breeding program: genomic characterization and pathological findings

Emerging infectious diseases in wildlife are increasingly associated with animal mortality and species declines, but their source and genetic characterization often remains elusive. Amphibian chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), has been associated with catastrophic and well-documented amphibian population declines and extinctions at the global scale. We used histology and whole-genome sequencing to describe the lesions caused by, and the genetic variability of, two Bd isolates obtained from a mass mortality event in a captive population of the threatened Chilean giant frog (Calyptocephalella gayi). This was the first time an association between Bd and high mortality had been detected in this charismatic and declining frog species. Pathological examinations revealed that 30 dead metamorphosed frogs presented agnathia or brachygnathia, a condition that is reported for the first time in association with chytridiomycosis. Phylogenomic analyses revealed that Bd isolates (PA1 and PA2) from captive C. gayi group with other Bd isolates (AVS2, AVS4, and AVS7) forming a single highly supported Chilean Bd clade within the global panzootic lineage of Bd (BdGPL). These findings are important to inform the strengthening of biosecurity measures to prevent the impacts of chytridiomycosis in captive breeding programs elsewhere

Eye Absence Does Not Regulate Planarian Stem Cells during Eye Regeneration

Dividing cells called neoblasts contain pluripotent stem cells and drive planarian flatworm regeneration from diverse injuries. A long-standing question is whether neoblasts directly sense and respond to the identity of missing tissues during regeneration. We used the eye to investigate this question. Surprisingly, eye removal was neither sufficient nor necessary for neoblasts to increase eye progenitor production. Neoblasts normally increase eye progenitor production following decapitation, facilitating regeneration. Eye removal alone, however, did not induce this response. Eye regeneration following eye-specific resection resulted from homeostatic rates of eye progenitor production and less cell death in the regenerating eye. Conversely, large head injuries that left eyes intact increased eye progenitor production. Large injuries also non-specifically increased progenitor production for multiple uninjured tissues. We propose a model for eye regeneration in which eye tissue production by planarian stem cells is not directly regulated by the absence of the eye itself. Keywords: planarian; regeneration; stem cell; eye; tissue turnover; target blind; progenitor; neoblastNational Institutes of Health (U.S.) (Grant R01GM080639

Reporte de análisis de datos de calidad del agua del Lago de Chapala

El reporte presenta los resultados más relevantes del análisis estadístico que se realizó a una base de datos que contenía información sobre los parámetros que son monitoreados dentro del Lago de Chapala. La base de datos dispone de información generada por la Comisión Nacional del Agua acerca de las concentraciones de diversos parámetros a partir de muestras obtenidas en las 34 estaciones de monitoreo ubicadas en diferentes puntos geográficos del Lago de Chapala, en un periodo de tiempo del 21 de noviembre de 2012 hasta el 8 de febrero de 2018. El análisis consistió en la sistematización de información y obtención de promedios globales de las concentraciones de los parámetros evaluados, así como del promedio por estación y por parámetro, la ubicación geográfica de éstos dentro del Lago de Chapala, y la comparación con los límites establecidos según las Normas Oficiales Mexicanas NOM-001-SEMARNAT-1996 y NOM-127-SSA1-1994 y con las concentraciones máximas recomendadas por las guías de agua potable, realizadas por la Organización Mundial de la Salud

¿O Panamá a caminho do desenvolvimento sustentável?

This article examines the long-term relationship between CO2 emissions, GDP and energy consumption in Panama during the period 1971-2011 through an autoregressive model of distributed delays to verify the cointegration of variables in the long term. The results confirm the presence of an environmental Kuznets curve and that CO2 emissions and energy consumption from primary sources do not affect economic growth and that environmental degradation increases with energy consumption. Finally, it makes some policy recommendations.Este artículo examina la relación de largo plazo entre emisiones de CO2, PIB y consumo de energía en Panamá durante el periodo 1971-2011 mediante un modelo autorregresivo de retardos distribuidos para comprobar la cointegración de las variables en el largo plazo. Los resultados confirman la presencia de una curva ambiental de Kuznets y que las emisiones de CO2 y el consumo de energía de fuentes primarias no afectan al crecimiento económico y que la degradación ambiental aumenta con el consumo de energía. Por último, hace recomendaciones de política.Este artigo examina a relação a longo prazo entre emissões de CO2, PIB e consumo de energia no Panamá durante o periodo 1971-2011, mediante um modelo autorregressivo de atrasos distribuídos para comprovar a cointegração das variáveis a longo prazo. Os resultados confirmam a presença de uma curva ambiental de Kuznets e que as emissões de CO2 e o consumo de energia de fontes primárias não afetam o crescimento econômico e que a degradação ambiental é aumentada com o consumo de energia. Por último, faz recomendações políticas

Oxidative Stress and Parkinson’s Disease: Effects on Environmental Toxicology

Epidemiological studies have found an increased risk of Parkinson’s disease (PD) with environmental factors such as exposure to substances derived from industrial processes, use of agrochemicals, or living in a rural environment. The hypothesis that certain environmental toxins could be the source of the EP is supported by the discovery that chemicals such as herbicides paraquat, diquat, and the fungicide maneb are selectively toxic in nigrostriatal dopaminergic neurons. Also, one of the insecticides produced by plants, such as rotenone, and by-product of the synthesis of synthetic heroin MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) can be reproduced in animal models where neurochemicals, histopathological, and clinical characteristic of PD can be found. Interestingly, there are similarities in the chemical structure of paraquat and MPTP. Recent evidence exhibited that inflammation and oxidative stress play an essential role in the development of PD. So, in our laboratory we found that in an animal model melatonin decreases the products of lipid oxidation, nitric oxide metabolites, and the activity of cyclooxygenase 2, which are induced by an intraperitoneal injection of MPTP. This suggests that the neuroprotective effects of melatonin are partially attributed to its antioxidant scavenging and anti-inflammatory action

Characterization of the biochemical and nutritional content in simple white grain maize (Zea mays L.) crosses

Our research focused on the characterization of the nutritional and biochemical content of 25 genotypes: 5 S4 inbred lines and the 20 possible single crosses formed between them, due to the lack of knowledge about the nutritional composition and its variation within the germplasm of the white corn breeding program. In kernels of each genotype we determined the content of oil, starch, protein, ash and phytic acid. Results showed that for the parents and the crosses, correspondingly, the intervals of the substances under study were: a) Oil: from 5.99 to 3.84 and 6.40 to 3.55 g ? 100 g-1, b) Protein:  from 8.26 to 5.43 and 9.83 to 5.56 g ? 100 g-1, c) Starch: from 88.25 to 74.48 and 96.64 to 72.57 g ? 100 g-1, d) Ash: from 1.90 to 1.20 and 2.0 to 0.89 g ? 100 g-1, e) Phytic acid: from 2.40 to 1.08 and 2.29 to 1.11 g ? 100 g-1. We observed that in comparison to the parents, the crosses only were significantly superior in the content of starch; although, within each group there were statistical differences of the contents. The crosses that showed higher contents for a nutritional component were those in which at least one parent had a high composition of the nutrient. The variation in the nutritional and biochemical content showed that there is diversity among genotypes, which is linked to the contrasting genetic origin of the inbred lines and is feasible to be used. This research showed the potential of taking advantage of the nutritional components of white corn through crosses (specially its starch content).E Objective: To characterize the nutritional and biochemical content of 25 genotypes: 5 S4 inbred lines and the 20 possible single crosses formed between them. Design/Methodology/Approach: The content of oil, starch, protein, ash and phytic acid was determined in kernels of each genotype, using the American Association of Cereal Chemists’ methods; the information obtained was analyzed by a complete randomized experimental design and Tukey’s means tests. Results: For the parents and the crosses, correspondingly, the intervals of the substances under study were: a) Oil: from 5.99 to 3.84 and 6.40 to 3.55 g ∙ 100 g-1, b) Protein:  from 8.26 to 5.43 and 9.83 to 5.56 g ∙ 100 g-1, c) Starch: from 88.25 to 74.48 and 96.64 to 72.57 g ∙ 100 g-1, d) Ash: from 1.90 to 1.20 and 2.0 to 0.89 g ∙ 100 g-1, e) Phytic acid: from 2.40 to 1.08 and 2.29 to 1.11 g ∙ 100 g-1. Study Limitations/Implications: The study shows that in comparison to the parents, the crosses were only significantly superior in the content of starch, although there were statistical differences of the contents within each group. The crosses that showed higher contents for a nutritional component were those in which at least one parent had a high composition of the nutrient. Findings/Conclusions: The variation in the nutritional and biochemical content showed that there is diversity among genotypes, which is linked to the contrasting genetic origin of the inbred lines and is feasible to be used. This research showed the potential of taking advantage of the nutritional components of white maize through crosses (specially its starch content)

Physiology and Pathology of Neuroimmunology: Role of Inflammation in Parkinson’s Disease

Parkinson’s disease (PD) is a neurodegenerative disease that affects 1% of the population aged 65 and over and is the second most common neurodegenerative disease next to Alzheimer’s disease. Interneuronal proteinaceous inclusions called Lewy bodies (LB) and a selective degeneration of dopaminergic neurons of the substantia nigra pars compacta (SNPC) are the main features of PD pathology. The most common clinical manifestations are rigidity, tremor, bradykinesia, postural instability, sleep disorders, alterations in gait, smell, memory, and dementia. Genetic and environmental factors are involved in PD, and, recently, oxidative stress, proteasome-mediated protein degradation, and inflammation have acquired relevance as major mechanisms of neuronal dysfunction. Increased levels of reactive oxygen and nitrogen species in the brain contribute to greater vulnerability of proteins to nitro-oxidative modification and to greater degrees of aggregation. These protein aggregates contain a variety of proteins of which α-synuclein appears to be the main structural component. Interestingly, α-synuclein can be secreted by neuronal cells and may lead the initiation and the maintenance of inflammatory events through the activation of microglia, which contributes to dopaminergic neuron depletion. New evidence also suggests that PD may be the result of an autoimmune response in which the immune cells recognize the neurons as foreign elements and would act against them, causing their death