Guerrero-Casado J.,University of Cordoba, Spain |
Guerrero-Casado J.,Technical University of Manabi |
Carpio A.J.,University of Cordoba, Spain |
Tortosa F.S.,University of Cordoba, Spain |
Tortosa F.S.,Escuela Superior Politecnica Agropecuaria de Manabi
Mammalian Biology | Year: 2016
The arrival of a new variant of rabbit haemorrhagic disease virus, known as RHDV2, has recently taken place in the native range of the European rabbit (Oryctolagus cuniculus), a keystone species which has undergone a sharp decline over the last sixty years as a consequence of certain harmful factors. Several works have noted the presence of this new variant in wild rabbit populations, and have in some cases recorded high mortality rates. However, little is known about the response to the arrival of this new virus variant at the population level. The goal of this work is therefore to show recent trends in 26 wild rabbit populations between 2010 (before the outbreak of the disease) and 2014 (after its onset) in two different ecosystems (woodland and agricultural areas), in order to test how their abundances changed over this period, which coincided with the spread of the RHDV2. Overall, our results showed that rabbit abundance was much lower in 2014 than in 2010, and that only 11.5% of the populations monitored proved to have a positive trend, that is, a higher abundance in 2014 than 2010. A positive correlation between rabbit abundance in 2010 and rabbit population trends was obtained, thus suggesting that the impact of the new variant on rabbit abundance is less evident in high density populations. Our results suggest that smaller rabbit populations are those most vulnerable to the outbreak of RHDV 2 and are therefore likely to decline sharply or even become extinct. © 2016 Deutsche Gesellschaft für Säugetierkunde.
Lerias J.R.,University of Lisbon |
Lerias J.R.,IBET Institute Biologia Experimental e Tecnologica |
Hernandez-Castellano L.E.,University of Las Palmas de Gran Canaria |
Morales-delaNuez A.,University of Las Palmas de Gran Canaria |
And 9 more authors.
Tropical Animal Health and Production | Year: 2013
Seasonal weight loss (SWL), caused by poor quality pastures during the dry season, is the major limitation to animal production in the tropics. One of the ways to counter this problem is to breed animals that show tolerance to SWL. The objective of this study was to understand the effect of feed restriction in milk production and live weight (LW) evolution in two goat breeds, with different levels of adaptation to nutritional stress: the Majorera (considered to be tolerant) and the Palmera (considered to be susceptible). A total of ten animals per breed were used. Animals were divided in four groups (two for each breed): a restricted group (restricted diet) and a control group. LW and milk yield parameters were recorded through a trial that lasted 23 days in total. Overall, there were no significant differences between both restricted groups, regarding neither LW nor milk yield reductions (LW reduction 13 % and milk yield reduction of 87 % for both restricted groups). In what concerns control groups, there were no significant differences between breeds, thought there were different increments at the end of the trial for both breeds regarding LW (6 and 4 %, for Majorera and Palmera, respectively) and milk yield (28 and 8 %, respectively for Majorera and Palmera). The lack of statistically significant differences between Palmera and Majorera LW and milk yields in restricted groups may be due to the fact that the controlled trial does not replicate harsh field conditions, in which Majorera would excel, and the stress induced by those differences. © 2013 Springer Science+Business Media Dordrecht.
Hydro-geomorphological hazard in catchments of the waraira repano national park south hillside, Distrito Capital, Venezuela [Amenaza hidrogeomorfológica: En microcuencas de la vertiente sur del Parque Nacional Waraira Repano, Distrito Capital, Venezuela]
Mendez W.,Libertador Experimental Pedagogical University |
Mendez W.,Technical University of Manabi |
Rivas L.,Libertador Experimental Pedagogical University |
Fernandez E.,Libertador Experimental Pedagogical University |
And 3 more authors.
Revista Geografica Venezolana | Year: 2016
Repeatedly, the flashfloods occurred in the Catuche, Anauco and Gamboa creeks and in the Cotiza river have severely affected neighborhoods and urban areas settled on their alluvial fans. Hence, it is necessary to assess the hydro-geomorphological hazard in their catchments and particularly the generation of flashfloods. The methodology considered the evaluation of the hydraulic conditions of the main channels and levels of human intervention, geomorphological photo-interpretation, characterization of rainfall patterns, measurements and calculations of morphometric parameters of the catchments, estimation of the concentration times, analysis of extreme rainfall events and estimation of flashflood peak discharges. Sudden hydrological responses are controlled by the morphometric parameters of the catchments and their drainage networks, as well as the dimensions of storms and the intensity and duration of rainfalls, which form significant flashflood peak discharges for different return periods. © 2016, Universidad de los Andes. All rights reserved.
Huang Q.,Chinese Institute of Urban Environment |
Huang Q.,Technical University of Manabi |
Chen Y.,Chinese Institute of Urban Environment |
Chi Y.,Chinese Institute of Urban Environment |
And 4 more authors.
Fish and Shellfish Immunology | Year: 2015
Perfluorooctane sulfonate (PFOS) and di(2-ethylhexyl) phthalate (DEHP) have both been reported to induce adverse effects including immunotoxicity. Despite the widespread presence of these two chemicals in estuaries and seawater, their health effects on marine fish have received little attention. Oryzias melastigma is a potential marine fish model for immunological studies. In the present study, immune-related genes in O.melastigma were enriched at the transcriptome level. Three-month-old fish were exposed to PFOS and DEHP (single or combined) for one week. The liver index-hepatosomatic index (HSI) of the fish was higher in the PFOS-exposed group and combined group than in the control group. This result indicates that PFOS might lead to liver toxicity. The mRNA level of interleukin-1 beta (IL1β) was upregulated after exposure. For catalase (CAT), glutathione peroxidase (GPx) and cluster of differentiation 3 (CD3), single exposure did not affect mRNA levels, but the combined exposure did significantly alter the expression of these genes. In all, our study provides a useful reference for immunotoxicological studies with O.melastigma; it also highlights the importance of assessing the combined effects of pollutant mixtures when determining the risk to aquatic organisms. © 2015 Elsevier Ltd.
Ruiz C.,Technical University of Manabi |
de J. May-Itza W.,Autonomous University of Yucatan |
Quezada-Euan J.J.G.,Autonomous University of Yucatan |
De la Rua P.,University of Murcia
Journal of Zoological Systematics and Evolutionary Research | Year: 2013
Transferred copies of mitochondrial DNA (mtDNA) into the nuclear genome (numts) have been reported in several Hymenoptera species, even at a high density in the honey bee nuclear genome. The accidental amplification of numts in phylogenetic studies focused on mtDNA highlights the importance of a correct determination of numts and their related mtDNA sequences. We report here the presence of numts derived from a mitochondrial rDNA 16S gene in the genome of the stingless bee species Melipona colimana and M. fasciata (tribe Meliponini) from Western Mexico. PCR products were cloned in both species obtaining thirty paralogous numts. Numts were identified by the presence of insertions and deletions and the disruption of the 16S secondary structure. Further phylogenetic analyses including alternative mitochondrial cox1 and nuclear ITS1 genes have revealed the presence of another numt (cox1) in the nuclear genome of these two species, and place both as sister lineages within the subgenus Michmelia. This is one of the first studies reporting the presence of numts in Meliponini species, and supports previous studies suggesting frequent transfer of mtDNA to the nuclear genome in Hymenoptera. Resumen: Copias nucleares de fragmentos mitocondriales (numts) y análisis filogenéticos en dos especies relacionadas de abejas sin aguijón del género Melipona (Hymenoptera: Meliponini): La transferencia de copias de ADN mitocondrial en el genoma nuclear (numt) ha sido descrita en varias especies de himenópteros, incluso con gran frecuencia en el genoma de la abeja melífera. La amplificación accidental de numts en estudios filogenéticos basados en ADN mitocondrial pone de manifiesto la importancia de identificar correctamente los numts y sus homólogos mitocondriales. En este estudio describimos la presencia de numts relacionados con el gen mitocondrial 16S en el genoma de las abejas sin aguijón Melipona colimana y M. fasciata (tribu Meliponini) de México occidental. Se clonaron los productos de PCR de ambas especies y se obtuvieron 31 copias parálogas de numts. Los numts se identificaron por la presencia de inserciones y deleciones así como por la ruptura en la estructura secundaria del gen ribosomal 16S. Los análisis filogenéticos incluyendo genes adicionales (el gen mitocondrial cox1 y el nuclear ITS1) han revelado la posible existencia de otro numt (cox1) en el genoma nuclear de estas dos especies y sitúan a ambas especies como linajes hermanos dentro del subgénero Michmelia. Este es uno de los primeros estudios en donde se describe la presencia de numts en especies de Meliponini y apoya a estudios previos que sugieren una transferencia frecuente del ADN mitocondrial en el genoma nuclear de los himenópteros. © 2013 Blackwell Verlag GmbH.