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Coronado L.M.,Institute Investigaciones Cientificas Y Servicios Of Alta Tecnologia Indicasat Aip
Journal of visualized experiments : JoVE | Year: 2013

Unlike other Plasmodium species, P. falciparum can be cultured in the lab, which facilitates its study (1). While the parasitemia achieved can reach the ≈40% limit, the investigator usually keeps the percentage at around 10%. In many cases it is necessary to isolate the parasite-containing red blood cells (RBCs) from the uninfected ones, to enrich the culture and proceed with a given experiment. When P. falciparum infects the erythrocyte, the parasite degrades and feeds from haemoglobin (2, 3). However, the parasite must deal with a very toxic iron-containing haem moiety (4, 5). The parasite eludes its toxicity by transforming the haem into an inert crystal polymer called haemozoin (6, 7). This iron-containing molecule is stored in its food vacuole and the metal in it has an oxidative state which differs from the one in haem (8). The ferric state of iron in the haemozoin confers on it a paramagnetic property absent in uninfected erythrocytes. As the invading parasite reaches maturity, the content of haemozoin also increases (9), which bestows even more paramagnetism on the latest stages of P. falciparum inside the erythrocyte. Based on this paramagnetic property, the latest stages of P. falciparum infected-red blood cells can be separated by passing the culture through a column containing magnetic beads. These beads become magnetic when the columns containing them are placed on a magnet holder. Infected RBCs, due to their paramagnetism, will then be trapped inside the column, while the flow-through will contain, for the most part, uninfected erythrocytes and those containing early stages of the parasite. Here, we describe the methodology to enrich the population of late stage parasites with magnetic columns, which maintains good parasite viability (10). After performing this procedure, the unattached culture can be returned to an incubator to allow the remaining parasites to continue growing. Source


De Leon L.F.,Institute Investigaciones Cientificas Y Servicios Of Alta Tecnologia Indicasat Aip | De Leon L.F.,McGill University | Podos J.,University of Massachusetts Amherst | Gardezi T.,McGill University | And 2 more authors.
Journal of Evolutionary Biology | Year: 2014

Adaptive radiation can be strongly influenced by interspecific competition for resources, which can lead to diverse outcomes ranging from competitive exclusion to character displacement. In each case, sympatric species are expected to evolve into distinct ecological niches, such as different food types, yet this expectation is not always met when such species are examined in nature. The most common hypotheses to account for the coexistence of species with substantial diet overlap rest on temporal variation in niches (often diets). Yet spatial variation in niche overlap might also be important, pointing to the need for spatiotemporal analyses of diet and diet overlap between closely related species persisting in sympatry. We here perform such an analysis by characterizing the diets of, and diet overlap among, four sympatric Darwin's ground finch species at three sites and over 5 years on a single Galápagos island (Santa Cruz). We find that the different species have broadly similar and overlapping diets - they are to some extent generalists and opportunists - yet we also find that each species retains some 'private' resources for which their morphologies are best suited. Importantly, use of these private resources increased considerably, and diet overlap decreased accordingly, when the availability of preferred shared foods, such as arthropods, was reduced during drought conditions. Spatial variation in food resources was also important. These results together suggest that the ground finches are 'imperfect generalists' that use overlapping resources under benign conditions (in space or time), but then retreat to resources for which they are best adapted during periods of food limitation. These conditions likely promote local and regional coexistence. © 2014 European Society For Evolutionary Biology. Source


Guzman H.M.,Smithsonian Tropical Research Institute | Diaz-Ferguson E.,Institute Investigaciones Cientificas Y Servicios Of Alta Tecnologia Indicasat Aip | Vega A.J.,University of Panama | Robles Y.A.,University of Panama
Revista de Biologia Tropical | Year: 2015

The dolphinfish (Coryphaena hippurus) is a highly migratory pelagic species commercially exploited by industrial, artisanal and recreational fisheries in tropical and subtropical areas of the world’s oceans. Herein, we evaluated the dolphinfish industrial fishery in Pacific Panama for the first time generating a growth model and examining fluctuations in annual total catch and in catch per unit effort (CPUE) over a four-year period (2006-2009). Annual and monthly catch values and biological parameters of 14 913 individuals were obtained onboard industrial vessels, landing sites and records from processing plants. Size frequency for industrial vessels showed a normal distribution between 353 and 1 715 mm (average, 1 010.85 mm; n = 10 459). Fish weight averaged 4.94 kg (SD). Sex ratio was slightly biased toward females. More than 90% of the analyzed fish were sexually mature. The length-weight relationship was positive and significant, reflecting allometric growth. Growth parameters using the von Bertalanffy equation revealed a growth efficiency of θ = 4.61, which is within the reported range for Coryphaena hippurus (3.95-4.70). The largest fish were between age classes 2 and 3 (700-1 400 mm). Total catch per year and catch per unit effort (CPUE) per year fluctuated, with the highest values recorded between 2008 and 2009. Catch values reported herein are preliminary and appear to be below those recorded elsewhere in the region and cautiously may represent an indicator of sustainable use of this marine resource even considering the absence of management actions in Panama. © 2015, Universidad de Costa Rica. All rights reserved. Source


Gonzalez-Wanguemert M.,University of Algarve | Vergara-Chen C.,University of Murcia | Vergara-Chen C.,Institute Investigaciones Cientificas Y Servicios Of Alta Tecnologia Indicasat Aip
Helgoland Marine Research | Year: 2014

Coastal lagoons are semi-isolated ecosystems exposed to wide fluctuations of environmental conditions and showing habitat fragmentation. These features may play an important role in separating species into different populations, even at small spatial scales. In this study, we evaluate the concordance between mitochondrial (previous published data) and nuclear data analyzing the genetic variability of Pomatoschistus marmoratus in five localities, inside and outside the Mar Menor coastal lagoon (SE Spain) using eight microsatellites. High genetic diversity and similar levels of allele richness were observed across all loci and localities, although significant genic and genotypic differentiation was found between populations inside and outside the lagoon. In contrast to the F ST values obtained from previous mitochondrial DNA analyses (control region), the microsatellite data exhibited significant differentiation among samples inside the Mar Menor and between lagoonal and marine samples. This pattern was corroborated using Cavalli-Sforza genetic distances. The habitat fragmentation inside the coastal lagoon and among lagoon and marine localities could be acting as a barrier to gene flow and contributing to the observed genetic structure. Our results from generalized additive models point a significant link between extreme lagoonal environmental conditions (mainly maximum salinity) and P. marmoratus genetic composition. Thereby, these environmental features could be also acting on genetic structure of coastal lagoon populations of P. marmoratus favoring their genetic divergence. The mating strategy of P. marmoratus could be also influencing our results obtained from mitochondrial and nuclear DNA. Therefore, a special consideration must be done in the selection of the DNA markers depending on the reproductive strategy of the species. © 2014 Springer-Verlag Berlin Heidelberg and AWI. Source


Mejia A.,Institute Investigaciones Cientificas Y Servicios Of Alta Tecnologia Indicasat Aip | Leijten P.,University of Oxford | Leijten P.,University of Amsterdam | Lachman J.M.,University of Oxford | Parra-Cardona J.R.,Michigan State University
Prevention Science | Year: 2016

Relevant achievements have been accomplished in prevention science with regard to disseminating efficacious parenting interventions among underserved populations. However, widespread disparities in availability of parenting services continue to negatively impact diverse populations in high-income countries (e.g., the USA) and low- and middle-income countries. As a result, a scholarly debate on cultural adaptation has evolved over the years. Specifically, some scholars have argued that in diverse cultural contexts, existing evidence-based parenting interventions should be delivered with strict fidelity to ensure effectiveness. Others have emphasized the need for cultural adaptations of interventions when disseminated among diverse populations. In this paper, we propose that discussions on cultural adaptation should be conceptualized as a “both-and,” rather than an “either-or” process. To justify this stance, we describe three distinct parenting intervention projects to illustrate how cultural adaptation and efficacy of evidence-based interventions can be achieved using contrasting approaches and frameworks, depending on cultural preferences and available resources of local contexts. Further, we suggest the need to develop guidelines for consistent reporting of cultural adaptation procedures as a critical component of future investigations. This discussion is relevant for the broader public health field and prevention science. © 2016 Society for Prevention Research Source

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