DNA Metabarcoding of Amazonian Ichthyoplankton Swarms.

Tropical rainforests harbor extraordinary biodiversity. The Amazon basin is thought to hold 30% of all river fish species in the world. Information about the ecology, reproduction, and recruitment of most species is still lacking, thus hampering fisheries management and successful conservation strategies. One of the key understudied issues in the study of population dynamics is recruitment. Fish larval ecology in tropical biomes is still in its infancy owing to identification difficulties. Molecular techniques are very promising tools for the identification of larvae at the species level. However, one of their limits is obtaining individual sequences with large samples of larvae. To facilitate this task, we developed a new method based on the massive parallel sequencing capability of next generation sequencing (NGS) coupled with hybridization capture. We focused on the mitochondrial marker cytochrome oxidase I (COI). The results obtained using the new method were compared with individual larval sequencing. We validated the ability of the method to identify Amazonian catfish larvae at the species level and to estimate the relative abundance of species in batches of larvae. Finally, we applied the method and provided evidence for strong temporal variation in reproductive activity of catfish species in the Ucayalí River in the Peruvian Amazon. This new time and cost effective method enables the acquisition of large datasets, paving the way for a finer understanding of reproductive dynamics and recruitment patterns of tropical fish species, with major implications for fisheries management and conservation.

Genetic structure in the Amazonian catfish Brachyplatystoma rousseauxii: influence of life history strategies.

The Dorado or Plateado (Gilded catfish) Brachyplatystoma rousseauxii (Pimelodidae, Siluriformes) is a commercially valuable migratory catfish performing the largest migration in freshwaters: from the Amazonian headwaters in the Andean foothills (breeding area) to the Amazon estuary (nursery area). In spite of its importance to inform management and conservation efforts, the genetic variability of this species has only recently begun to be studied. The aim of the present work was to determine the population genetic structure of B. rousseauxii in two regions: the Upper Madera Basin (five locations in the Bolivian Amazon) and the Western Amazon Basin (one regional sample from the Uyucalí-Napo-Marañon-Amazon basin, Peru). Length polymorphism at nine microsatellite loci (284 individuals) was used to determine genetic variability and to identify the most probable panmictic units (using a Bayesian approach), after a significant departure from Hardy-Weinberg equilibrium was observed in the overall dataset (Western Amazon + Upper Madera). Bayesian analyses revealed at least three clusters in admixture in the five locations sampled in the Bolivian Amazon, whereas only two of these clusters were observed in the Western Amazon. Considering the migratory behaviour of B. rousseauxii, different life history strategies, including homing, are proposed to explain the cluster distribution. Our results are discussed in the light of the numerous threats to the species survival in the Madera basin, in particular dam and reservoir construction.

Population genetic structure of Cichla pleiozona (Perciformes: Cichlidae) in the Upper Madera basin (Bolivian Amazon): sex-biased dispersal?

This study investigates the population structure of the Tucunaré (Cichla pleiozona) in the Bolivian Amazon (Upper Madera) by using nuclear (EPIC-PCR, 67 individuals) and mitochondrial (Control Region, 41 published and 76 new sequences) DNA analyses, in relation with ecological (water quality: muddy, clear and mix) and geographic factors. Our analyses of both markers showed the highest diversity in clear waters (Yata, Middle and Upper Iténez), and the existence of two populations in muddy waters (Sécure and Ichilo) and one in mix waters (Manuripi). On the other hand, mitochondrial analyses identified three populations in clear waters where nuclear analyses identified a panmictic population. The highest diversity observed in the Yata-Iténez system suggests that an aquatic refuge occurred during the past in this area. The possible explanations for the observed discrepancy between nuclear and mitochondrial markers are discussed, and a sex-biased dispersal seems to be the most plausible hypothesis in the light of the available information and field observations.

Adolescencia y maternidad / Adolescence and maternity

Se estudia el embarazo en la adolescencia en la Provincia de Melipilla durante los años 1999, 2000 y 2001. Se observó que la gestación en la adolescencia conlleva problemas de bajo peso en los recién nacidos, (42,2 por ciento de los niños con peso < a 3.000 g). Destaca, además, el bajo nivel socioeconómico de las madres perteneciendo el 70 por ciento de ellas al grupo considerando dentro nivel de pobreza. La educación de las madres es un 32,5 por ciento no supera la enseñanza básica incompleta. Los hijos de las adolescentes, tuvieron en promedio cuatro consultas médicas al año por morbilidad, siendo la patología respiratoria la de mayor consulta (47,7 por ciento). En síntesis el desafío para la Salud Pública de esta zona, es un riguroso seguimiento de las madres adolescentes embarazadas a objeto de mejorar su alimentación. Además, es necesario organizar programas educativos ministeriales conjuntos para disminuir el gran porcentaje de mujeres adolescentes con bajo nivel educacional, que se embarazan.

Emotional and psychosocial factors in burn patients during hospitalization.

This is a preliminary study of psychological symptoms, prior psychosocial adjustment and severity of injury in 25 consecutive burn patients. All had suffered burns in work-related accidents and were evaluated by the psychiatric consulation-liaison team during their initial hospitalization in the Burn Unit of the Hospital del Trabajador, Santiago. All patients were clinically evaluated and the following instruments were applied: Hamilton Scales of Anxiety (HAM-A) and Depression (HAM-D), Goldberg's General Health Questionnaire (GHQ-28), Cloninger's Tridimensional Personality Questionnaire (TPQ) and a modified version of a Schooler's Adjustment Scale. No significant correlation was found between extent and severity of burns and anxious or depressive symptoms. However, all patients had burns that varied from mild to moderate; there were no severe and extensive injuries. A significant correlation was found between anxiety and the harm avoidance dimension in the TPQ, as would be expected. Patients with poor psychosocial adjustment presented with greater anxiety symptoms. A significant negative correlation was also found between degree of anxiety symptoms and income level. The main findings are in agreement with current literature. They emphasize the relevance of prior psychosocial adjustment and personality as probable factors of psychological symptoms. The need to control pain as a variable is also pointed out.

Mastitis survey in Bolivia.

Quarter milk samples were taken from 1,090 cows on 24 dairy farms in southeastern Bolivia. Nineteen per cent were positive in the milk quality test for subclinical mastitis, 12% for presence of potentially pathogenic bacteria and 4% for both. The prevalence of infection was related to management factors.