Bases ecològiques per a la recerca de nous fàrmacs en els organismes marins

Hi ha una diversitat extraordinària de molècules bioactives en els éssers vius, les quals han estat utilitzades com a font de medicaments des de l'antiguitat. De fet, la major part dels medicaments que existeixen actualment al mercat són productes naturals o en deriven. Durant els darrers cinquanta anys, la investigació per al desenvolupament de nous fàrmacs a partir de productes naturals s'ha centrat en el mar, un medi poc explorat i amb unes condicions físiques particulars, les quals suggereixen la presència d'estructures químiques noves en el seus habitants. Les interaccions mitjançant substàncies bioactives estan ben esteses entre els organismes marins, ja que el mar ofereix una visibilitat molt inferior a la del medi aeri (terrestre) i a dins seu, per tant, les pistes químiques adquireixen una major rellevància. D'altra banda, a més dels vegetals, al mar s'ha desenvolupat una estratègia de vida animal, absent del medi terrestre. Aquesta estratègia està representada pels invertebrats sedentaris (fixos al fons marí), els quals, per evitar ser recoberts per altres organismes de creixement més ràpid (epibionts) o depredats pels animals mòbils, han desenvolupat una capacitat especial per produir substàncies bioactives de defensa, les quals han resultat tenir un interès potencial en farmacologia. En aquest estudi es descriu com la investigació de nous fàrmacs d'origen marí ha viatjat de la mà de la química de productes naturals i de l'ecologia química, i com aquestes investigacions representen un model en el qual la ciència bàsica i l'aplicada caminen en paral·lel. També, es revisa l'estat actual del coneixement en aquests camps i es mencionen les línies d'investigació actuals i la seva evolució previsible en un futur pròxim.Natural beings contain an extraordinary diversity of bioactive molecules, which have been used as a source of medicines since the Antiquity. The majority of the available drugs in the market, are or derive from natural products. During the last 50 years, the research for the development of new drugs from natural substances has focused on the marine environment. Marine organisms have been comparatively less explored than terrestrial ones and are thought to produce unusual chemical structures because of the particular physical characteristics of marine waters. The interactions mediated by bioactive substances are widespread among marine beings, since they inhabit a low-visibility environment where the chemical cues become particularly relevant. Moreover, besides vegetables (algae), in the sea, there is an animal form of life that does not exist in the terrestrial environment. This form of life is represented by sessile invertebrates (attached to the sea bottom as adults), which are particularly prone to develop a set of mechanisms to avoid being covered by other fast-growing organisms (epibionts) or predated by mobile animals. Among these mechanisms, the production of defensive chemicals is preponderant, and these chemicals have been found applications in the pharmacological industry. In this study, I describe the way the investigation on new drugs of marine origin has developed in parallel to that on natural products and on chemical ecology and how this research field is a model in which basic and applied sciences go close together. Furthermore, I review the state of the art of the research in these fields and outline the current research topics and their foreseeable evolution in the forthcoming years

Population genetics at three spatial scales of a rare sponge living in fragmented habitats

<p>Abstract</p> <p>Background</p> <p>Rare species have seldom been studied in marine habitats, mainly because it is difficult to formally assess the status of rare species, especially in patchy benthic organisms, for which samplings are often assumed to be incomplete and, thus, inappropriate for establishing the real abundance of the species. However, many marine benthic invertebrates can be considered rare, due to the fragmentation and rarity of suitable habitats. Consequently, studies on the genetic connectivity of rare species in fragmented habitats are basic for assessing their risk of extinction, especially in the context of increased habitat fragmentation by human activities. Sponges are suitable models for studying the intra- and inter-population genetic variation of rare invertebrates, as they produce lecitotrophic larvae and are often found in fragmented habitats.</p> <p>Results</p> <p>We investigated the genetic structure of a Mediterranean sponge, <it>Scopalina lophyropoda </it>(Schmidt), using the allelic size variation of seven specific microsatellite loci. The species can be classified as "rare" because of its strict habitat requirements, the low number of individuals per population, and the relatively small size of its distribution range. It also presents a strong patchy distribution, philopatric larval dispersal, and both sexual and asexual reproduction. Classical genetic-variance-based methods (AMOVA) and differentiation statistics revealed that the genetic diversity of <it>S. lophyropoda </it>was structured at the three spatial scales studied: within populations, between populations of a geographic region, and between isolated geographic regions, although some stochastic gene flow might occur among populations within a region. The genetic structure followed an isolation-by-distance pattern according to the Mantel test. However, despite philopatric larval dispersal and fission events in the species, no single population showed inbreeding, and the contribution of clonality to the population makeup was minor (only ca. 4%).</p> <p>Conclusions</p> <p>The structure of the <it>S. lophyropoda </it>populations at all spatial scales examined confirms the philopatric larval dispersal that has been reported. Asexual reproduction does not seem to play a relevant role in the populations. The heterozygote excess and the lack of inbreeding could be interpreted as a hitherto unknown outcrossing strategy of the species. The envisaged causes for this strategy are sperm dispersal, a strong selection against the mating of genetically related individuals to avoid inbreeding depression or high longevity of genets combined with stochastic recruitment events by larvae from other populations. It should be investigated whether this strategy could also explain the genetic diversity of many other patchy marine invertebrates whose populations remain healthy over time, despite their apparent rarity.</p

High genetic diversity, phenotypic plasticity, and invasive potential of a recently introduced calcareous sponge, fast spreading across the Atlanto‑Mediterranean basin

16 páginas, 6 tablas, 8 figuras.Sponges are considered poor invaders, and no genetic studies on introduced sponges have been performed up to now. Paraleucilla magna is the first calcareous sponge introduced to the Mediterranean and Northeastern Atlantic. The study aimed at investigating the genetic makeup and connectivity of the introduced populations of P. magna and at exploring signs of local phenotypic adaptation, to gain insight on the species invasive potential. Ten populations along the species introduction range (Brazil, Açores, Madeira, and continental Europe) were genetically characterized by using nine microsatellite markers. Most populations were genetically structured as suggested by significant Dst and Fst values, significant differences among populations (AMOVA) and the presence of private alleles. The analyzed populations belonged to three genetically homogeneous groups (K) according to the Bayesian algorithm (structure software) and the UPGMA dendrogram. Genetic diversity within populations was higher than expected. Recurrent introductions of non-randomly selected individuals from the native sources may have contributed to the heterozygote deficit found in all populations by forming pedigree structures with mating among relatives. Moreover, the species biological cycle was monitored in a population established on native Mediterranean assemblages (41°40′27″N, 2°47′25″E) and compared with the species cycle in other habitats. Contrasting life spans, growth habits, and reproduction cycles, depending on the habitat conditions, were recorded. To summarize, high genetic diversity, phenotypic local adaptation, and high reproduction rates altogether allow predicting the fast proliferation of P. magna in newly colonized regions and point to its strong invasive potential.This study has been partially funded by MARSYMBIOMICS project ref. CTM2013-43287-P (Spanish Ministry of Economy and Competitiveness (MINECO)—FECYT agency, and Consolidate Group Award 2009-SGR655 (Generalitat of Catalonian) to MJU. MG has benefited from a FPU fellowship from the Spanish MINECO and JF from a Marie Curie (EU) fellowship, associated, respectively, with the BENTHOMICS and BIOCAPITAL projects to MJU.Peer reviewe

Sistema no invasivo para medir niveles de glucosa en sangre

El objetivo de este trabajo es desarrollar los circuitos electrónicos para un sensor de niveles de glucosa en sangre. El sistema es no invasivo, por lo que elimina el pinchazo en el dedo que deben realizarse los individuos que padecen de diabetes cada vez que desean conocer su nivel de glucosa.Área: Ingeniería, Arquitectura y Tecnología

Un nuevo registro de graptolithina en la formación Río Bonete (Ordovícico), precordillera de Jagüé, La Rioja

Fil: Frigerio, Paula Verónica. Becaria ANPCYT - Centro de Investigaciones Geológicas, calle 1 nro. 644, 1900, La Plata, Buenos. AiresFil: Uriz, Norberto J.. Departamento Científico de Geología del Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900, La Plata, Buenos AiresFil: Alfaro, Marta. Departamento Científico de Geología del Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n, 1900, La Plata, Buenos Aire

Análisis de la procedencia e historia tectónica del Paleozoico inferior sedimentario del sector oriental del Macizo Norpatagónico : correlaciones e implicancias paleogeográficas

Tesis presentada para optar al Grado de Doctor en Ciencias NaturalesFil: Uriz, Norberto J.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo; Argentin

A Silurian-Devonian muddy platform-delta system (Río Seco de los Castaños Fm) in the San Rafael Block, Mendoza Province, Argentina

Fil: Manassero, Marcelo Jorge. CIG- Centro de Investigaciones Geológicas, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, 1-644, 1900 La Plata, ArgentinaFil: Cingolani, Carlos Alberto. Centro de Investigaciones Geológicas (CONICET-UNLP) y División Geología del Museo de La Plata, La PlataFil: Uriz, Norberto J.. División Geología del Museo de La Plata, La Plat

Comedia onírica, por August Strindberg

Reseña de "Comedia onírica, por August Strindberg" de August Strindberg, por Francisco J. Uriz. 30 julio, 200

Las rocas monzoníticas del sector oriental del Plutón de Cacheuta, Precordillera mendocina : Características geoquímicas y edad U/Pb (LA-ICP-MS)

Fil: Cingolani, Carlos Alberto. Centro de Investigaciones Geológicas (CIG). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Uriz, Norberto J.. División Geología. Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; ArgentinaFil: Chemale, Farid. Instituto de Geociências. Universidade de Brasília; BrasilFil: Varela, Ricardo. Centro de Investigaciones Geológicas (CIG). Facultad de Ciencias Naturales y Museo. Universidad Nacional de La Plata; Argentin