Genetic Structure of a Native Neotropical Fish Species: New Insights about a South American Bioindicator.

The biodiversity of Neotropical region is affected by anthropogenic disturbance. Throughout Brazil, Argentina and Uruguay, the native fish, Cnesterodon decemmaculatus, is well distributed and widely used as an excellent bioindicator of environmental quality. We investigated the diversity and genetic structure of its populations along a water pollution gradient to answer the following questions: 1- Does the genetic diversity decrease under the stressful conditions of a severe water quality gradient? and 2- Is there any relationship between the haplotypes registered along the studied basin and those recorded in other distant basins? Two mitochondrial DNA markers, Cytochrome b and D-loop, were analyzed and four haplotypes were registered for both markers along the basin. H1 was present throughout all the river sections in high frequencies leading to a low genetic diversity. We suggest that only a few haplotypes tolerate the stressful conditions of mountain rivers. On the other hand, the presence of H4 at the site located downstream suggests a history of recent colonization from the southeast to the northwest of the biome. These results, together with the abundance decrease along the pollution gradient, and the non-migratory characteristic of C. decemmaculatus suggest that its populations may be at risk of local extinction.

Effects of water quality on aspects of reproductive biology of Cnesterodon decemmaculatus.

The Suquía River basin (Córdoba, Argentina) is under a strong negative impact due to multiple sources of anthropic pollution. The main goal of our study was to evaluate if variations in the water quality of Suquía river basin affect the reproductive biology of Cnesterodon decemmaculatus and determine if the responses provided by the species can be considered as biomarkers of river quality. This assessment was performed through the measurement of morphological, histological and somatic parameters in adult males collected at four sampling sites during the beginning and the end of the breeding season. The water quality evaluation carried out through the estimation of a water quality index (WQI) and pesticides concentrations in water, revealed a pollution gradient along the studied basin. The same variation pattern was registered for the somatic index. In addition, the analysis of the morphology of the male copulatory organ (gonopodium) showed that individuals collected at Córdoba city had the lowest Gonopodium-Somatic Index (Gonop-SI) value, while those sampled at the most polluted site showed abnormalities in the small structures of the gonopodium. On the other hand, few histological alterations were found in the liver whereas no alterations were found in gonads along the river. The results obtained allowed us to characterize the environmental conditions of the studied basin and demonstrated the water quality deterioration along the Suquía River.

Guidelines for incorporating scientific knowledge and practice on rare diseases into higher education: neuronal ceroid lipofuscinoses as a model disorder.

This article addresses the educational issues associated with rare diseases (RD) and in particular the Neuronal Ceroid Lipofuscinoses (NCLs, or CLN diseases) in the curricula of Health Sciences and Professional's Training Programs. Our aim is to develop guidelines for improving scientific knowledge and practice in higher education and continuous learning programs. Rare diseases (RD) are collectively common in the general population with 1 in 17 people affected by a RD in their lifetime. Inherited defects in genes involved in metabolism are the commonest group of RD with over 8000 known inborn errors of metabolism. The majority of these diseases are neurodegenerative including the NCLs. Any professional training program on NCL must take into account the medical, social and economic burdens related to RDs. To address these challenges and find solutions to them it is necessary that individuals in the government and administrative authorities, academia, teaching hospitals and medical schools, the pharmaceutical industry, investment community and patient advocacy groups all work together to achieve these goals. The logistical issues of including RD lectures in university curricula and in continuing medical education should reflect its complex nature. To evaluate the state of education in the RD field, a summary should be periodically up dated in order to assess the progress achieved in each country that signed up to the international conventions addressing RD issues in society. It is anticipated that auditing current practice will lead to higher standards and provide a framework for those educators involved in establishing RD teaching programs world-wide.

The neuronal ceroid lipofuscinoses program: A translational research experience in Argentina.

BACKGROUND: The Argentinean program was initiated more than a decade ago as the first experience of systematic translational research focused on NCL in Latin America. The aim was to overcome misdiagnoses and underdiagnoses in the region. SUBJECTS: 216 NCL suspected individuals from 8 different countries and their direct family members. METHODS: Clinical assessment, enzyme testing, electron microscopy, and DNA screening. RESULTS AND DISCUSSION: 1) The study confirmed NCL disease in 122 subjects. Phenotypic studies comprised epileptic seizures and movement disorders, ophthalmology, neurophysiology, image analysis, rating scales, enzyme testing, and electron microscopy, carried out under a consensus algorithm; 2) DNA screening and validation of mutations in genes PPT1 (CLN1), TPP1 (CLN2), CLN3, CLN5, CLN6, MFSD8 (CLN7), and CLN8: characterization of variant types, novel/known mutations and polymorphisms; 3) Progress of the epidemiological picture in Latin America; and 4) NCL-like pathology studies in progress. The Translational Research Program was highly efficient in addressing the misdiagnosis/underdiagnosis in the NCL disorders. The study of "orphan diseases" in a public administrated hospital should be adopted by the health systems, as it positively impacts upon the family's quality of life, the collection of epidemiological data, and triggers research advances. This article is part of a Special Issue entitled: "Current Research on the Neuronal Ceroid Lipofuscinoses (Batten Disease)".