Simple Protocol for Secondary School Hands-On Activity: Electrophoresis of Pre-Stained Nucleic Acids on Agar-Agar Borate Gels

An extremely simple, inexpensive, and safe method is presented, which emulates nucleic acids isolation and electrophoretic analysis as performed in a research environment, in the context of a secondary school hands-on activity. The protocol is amenable to an interdisciplinary approach, taking into consideration the electrical and chemical parameters of the electrophoretic system. Furthermore, the laboratory is framed in a more comprehensive pedagogical setting, which addresses the methodological aspects of a pivotal scientific enterprise such as the Human Genome Project. In this setting, the hands-on activity is complemented with animations, paper models, and discussions. Additionally, our results indicate that the use of borate buffer and agar-agar gels suits many of the experiments included in college-level laboratory activities, which currently make use of more expensive agarose gels and TBE or TAE buffer

Asymmetry in genitalia is in sync with lateralized mating behavior but not with the lateralization of other behaviors

Asymmetries in bilateral organisms attract a lot of curiosity given that they are conspicuous departures from the norm. They allow the investigation of the integration at different levels of biological organization. Here we study whether and how behavioral and asymmetrical anatomical traits co-evolved and work together. We ask if asymmetry is determined locally for each trait or at a whole individual level in a species bearing conspicuous asymmetrical genitalia. Asymmetric genitalia evolved in many species; however, in most cases the direction of asymmetry is fixed. Therefore, it has been rarely determined if there is an association between the direction of asymmetry in genitalia and other traits. In onesided livebearer fish of the genus Jenynsia (Cyprinodontiformes, Anablepidae), the anal fin of males is modified into a gonopodium, an intromittent organ that serves to inseminate females. The gonopodium shows a conspicuous asymmetry, with its tip bending either to the left or the right. By surveying 13 natural populations of Jenynsia lineata, we found that both genital morphs are equally common in wild populations. In a series of experiments in a laboratory population, we discovered asymmetry and lateralization for multiple other traits; yet, the degree of integration varied highly among them. Lateralization in exploratory behavior in response to different stimuli was not associated with genital morphology. Interestingly, the direction of genital asymmetry was positively correlated with sidedness of mating preference and the number of neuromasts in the lateral line. This suggests integration of functionally linked asymmetric traits; however, there is no evidence that asymmetry is determined at the whole individual level in our study species.Fil: Torres Dowdall, Julián Roberto. Universität Konstanz; AlemaniaFil: Rometsch, Sina J.. Universität Konstanz; AlemaniaFil: Aguilera, Gaston. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; Argentina. Fundación Miguel Lillo. Dirección de Zoología. Instituto de Vertebrados. Sección Ictiología; ArgentinaFil: Goyenola, Guillermo. Universidad de la Republica. Centro Universitario Regional del Este.; UruguayFil: Meyer, Axel. Universität Konstanz; Alemani

Empirical modelling of stream nutrients for countries without robust water quality monitoring systems

Water quality models are useful tools to understand and mitigate eutrophication processes. However, gaining access to high-resolution data and fitting models to local conditions can interfere with their implementation. This paper analyzes whether it is possible to create a spatial model of nutrient water level at a local scale that is applicable in different geophysical and land-use conditions. The total nitrogen and phosphorus concentrations were modeled by integrating Geographical Information Systems, Remote Sensing, and Generalized Additive and Land-Use Changes Modeling. The research was based on two case studies, which included 204 drainage basins, with nutrient and limnological data collected during two seasons. The models performed well under local conditions, with small errors calculated from the independent samples. The recorded and predicted concentrations of nutrients indicated a significant risk of water eutrophication in both areas, showing the impact of agricultural intensification and population growth on water quality. The models are a contribution to the sustainable land-use planning process, which can help to prevent or promote land-use transformation and new practices in agricultural production and urban design. The ability to implement models using secondary information, which is easily collected at a low cost, is the most remarkable feature of this approach.Universidad de la República. Comisión Sectorial de Investigación CientíficaAgencia Nacional de Investigación e InnovaciónPrograma de Desarrollo de las Ciencias Básicas - Geociencia

Producción, nutrientes, eutrofización y cianobacterias en Uruguay : armando el rompecabezas

Si bien las causas y consecuencias de la eutrofización son múltiples, este artículo analiza aspectos fundamentales en el contexto actual en Uruguay, con especial énfasis en las floraciones cianobacterianas como una de las consecuencias más frecuentes y notorias. El agravamiento de la eutrofización y sus síntomas, que se predicen con el cambio climático; las claves para la reducción de las pérdidas difusas de fósforo hacia el agua superficial en suelos bajo uso agropecuario; y los cambios actuales y futuros en la gobernanza del agua y la gestión ambiental, son algunos de los temas más importantes considerados. En el análisis se identifican también múltiples desafíos, tanto en la generación de conocimiento como en la gestión ambiental asociada

Produção, nutrientes, eutrofização e cianobactérias no Uruguai: montando o quebra-cabeça

Despite there are multiple causes and consequences of eutrophication, this article analyses key aspects in the current context of Uruguay, emphasizing on cyanobacterial blooms as one of the most frequent and noticeable consequences. The worsening of eutrophication and its symptoms predicted with climate change, the keys for the reduction of diffuse losses of phosphorus with surface runoff on agricultural lands and the ongoing and future changes of water governance and management of the problem are some of the most important issues considered here. In this analysis, we also identify several challenges, both to fill knowledge gaps and in the arena of environmental management.Si bien las causas y consecuencias de la eutrofización son múltiples, este artículo analiza aspectos fundamentales en el contexto actual en Uruguay, con especial énfasis en las floraciones cianobacterianas como una de las consecuencias más frecuentes y notorias. El agravamiento de la eutrofización y sus síntomas, que se predicen con el cambio climático; las claves para la reducción de las pérdidas difusas de fósforo hacia el agua superficial en suelos bajo uso agropecuario; y los cambios actuales y futuros en la gobernanza del agua y la gestión ambiental, son algunos de los temas más importantes considerados. En el análisis se identifican también múltiples desafíos, tanto en la generación de conocimiento como en la gestión ambiental asociada.  Embora as causas e consequências da eutrofização sejam múltiplas, este artigo analisa aspectos fundamentais no contexto atual no Uruguai, com ênfase especial nas florações de cianobactérias como uma das consequências mais frequentes e notórias. O agravamento da eutrofização e seus sintomas previstos pelas mudanças climáticas, as chaves para reduzir as perdas difusas de fósforo para as águas superficiais em solos sob uso agrícola e as mudanças atuais e futuras na governança da água e gestão ambiental, são algumas das questões mais importantes consideradas. A análise também identifica múltiplos desafios, tanto na geração de conhecimento como na gestão ambiental associada

Campsurus violaceus (Ephemeroptera, Polymitarcyidae) in a subtropical reservoir: control factors and relationship with the macroinvertebrate community

Campsurus violaceus is a benthic species that play an important role in sediment bioturbation processes. We explored aspects of its basic biology and life-cycle in a subtropical lake (Laguna del Sauce, Uruguay). We elucidated the habitat preference of C. violaceus and evaluated if might foster a more diverse and abundant macroinvertebrate community. The population of C. violaceus showed univoltine behavior with nymphs all year around. The spatial distribution of Campsurus in the system was related with various sediment attributes, particularly granulometry. A clear positive relationship between abundance of C. violaceus and the associated macroinvertebrate community was found. This association could not be explained by the availability of basal resources, nor sediment preferences, but direct or indirect biotic interactions appeared to be importan

A Global Assessment of the Effects of Eucalyptus Plantations on Stream Ecosystem Functioning

Forest change is a major environmental problem worldwide. Forest streams, with their large aquatic–terrestrial interface and strong dependence on terrestrially derived organic matter, are highly sensitive to forest changes. Fast-wood plantations can be particularly threatening if they markedly differ from native forests. Eucalyptus plantations, in particular, cover large areas worldwide (> 20 million ha, mostly from 35°S to 35°N), but their effects on stream functioning have been addressed mostly in the Iberian Peninsula, which limits generalization to other regions. We assessed the effect of eucalyptus plantations on total (microbial decomposers and macroinvertebrates; in coarse mesh bags) and microbial-driven (in fine mesh bags) leaf litter decomposition by comparing streams flowing through native forests and eucalyptus plantations in seven regions in the Iberian Peninsula, Central Africa and South America. We found an overall significant inhibition of total litter decomposition by 23%. The effect did not significantly differ across regions, although a significant inhibition was found for Spain (− 41%), South Brazil (− 31%) and Uruguay (− 36%) (Portugal had a marginally nonsignificant inhibition by 50%) but not for other regions, suggesting that the effects of plantations in temperate climates are mediated through effects on macroinvertebrate communities. Contrarily, the overall effect for microbial-driven litter decomposition was non-significant, but it significantly differed across regions with a significant stimulation in Central Brazil (110%) and Uruguay (32%), and nonsignificant effects for other regions (Kenya had a marginally nonsignificant inhibition by 48%), suggesting that functional redundancy among microbial communities is not general and effects can occur if plantations induce changes in nutrient availability, solar irradiation or litter characteristics

Influence of Farming Intensity and Climate on Lowland Stream Nitrogen

Nitrogen lost from agriculture has altered the geochemistry of the biosphere, with pronounced impacts on aquatic ecosystems. We aim to elucidate the patterns and driving factors behind the N fluxes in lowland stream ecosystems differing about land-use and climatic-hydrological conditions. The climate-hydrology areas represented humid cold temperate/stable discharge conditions, and humid subtropical climate/flashy conditions. Three complementary monitoring sampling characteristics were selected, including a total of 43 streams under contrasting farming intensities. Farming intensity determined total dissolved N (TDN), nitrate concentrations, and total N concentration and loss to streams, despite differences in soil and climatic-hydrological conditions between and within regions. However, ammonium (NH4+) and dissolved organic N concentrations did not show significant responses to the farming intensity or climatic/hydrological conditions. A high dissolved inorganic N to TDN ratio was associated with the temperate climate and high base flow conditions, but not with farming intensity. In the absence of a significant increase in farming N use efficiency (or the introduction of other palliative measures), the expected farming intensification would result in a stronger increase in NO3−, TDN, and TN concentrations as well as in rising flow-weighted concentrations and loss in temperate and subtropical streams, which will further exacerbate eutrophication

Incidence of Watershed Land Use on the Consumption of Meso and Microplastics by Fish Communities in Uruguayan Lowland Streams

Physical-chemical and biologicaldiversity of streams are influenced by the land use in their watersheds. Plastics currently make up the most important waste asset, representing an important part of the transported and accumulated material in water courses. This work analyzes the consumption of plastics debris by the fish communities in streams with two contrasting types of land use. We worked with threestreams impacted by urbanization and threeby extensive ranching. The stomach and intestinal contents of 309 individuals of 29 species were analyzed, by a modified alkaline digestion, and observed under a stereo microscope with polarized light. A total of 373 plastic itemswere found, of which the majority corresponded to fibers (318). A significant difference was found between the percentage of individuals that consumed plastic debrisbetween both systems (51.6% in ranchers and 76.6% in urban, p = 0.014 Mood’s Median), but no difference was found in the average ingested per individual. This study establishes the first baseline on plastic debris consumption by fish in Uruguayan streams, showing the extent of the plastic and microplastic pollution problem. Although there are differences between the analyzed sites, we also observed significant contamination in streams far from urbanization