The east-west-north colonization history of the Mediterranean and Europe by the coastal plant Carex extensa (Cyperaceae).

Coastal plants are ideal models for studying the colonization routes of species because of the simple linear distributions of these species. Carex extensa occurs mainly in salt marshes along the Mediterranean and European coasts. Variation in cpDNA sequences, amplified fragment length polymorphisms (AFLPs) and simple sequence repeats (SSRs) of 24 populations were analysed to reconstruct its colonization history. Phylogenetic relationships indicate that C. extensa together with the South American Carex vixdentata and the southern African Carex ecklonii form a monophyletic group of halophilic species. Analyses of divergence times suggest that early lineage diversification may have occurred between the late Miocene and the late Pliocene (Messinian crisis). Phylogenetic and network analyses of cpDNA variation revealed the monophyly of the species and an ancestral haplotype contained in populations of the eastern Mediterranean. The AFLP and SSR analyses support a pattern of variation compatible with these two lineages. These analyses also show higher levels of genetic diversity and differentiation in the eastern population group, which underwent an east-to-west Mediterranean colonization. Quaternary climatic oscillations appear to have been responsible for the split between these two lineages. Secondary contacts may have taken place in areas near the Ligurian Sea in agreement with the gene flow detected in Corsican populations. The AFLP and SSR data accord with the 'tabula rasa' hypothesis in which a recent and rapid colonization of northern Europe took place from the western Mediterranean after the Last Glacial Maximum. The unbalanced west-east vs. west-north colonization may be as a result of 'high density blocking' effect.

Utilidad de las tiras reactivas de orina en el diagnóstico de infección de tracto urinario inferior no complicada / Utility of dipstick tests for the diagnostic of non complicated urinary tract infections

Las infecciones urinarias ocupan el segundo lugar entre las infecciones atendidas en Atención Primaria. El diagnóstico de certeza es el urocultivo. Como técnicas rápidas se utilizan los tests de esterasa leucocitaria y nitritos en orina, pero en la bibliografía su sensibilidad y especificidad son muy variables. Objetivos: evaluar la validez de las tiras reactivas de orina en el diagnóstico de infección del tracto urinario inferior no complicada en nuestro medio, en términos de sensibilidad y especificidad empleando como método de referencia el urocultivo. Comparar el resultado de la tira en consulta y en el laboratorio. Estudiar síntomas predictores de enfermedad y test positivo. Sujetos y métodos: estudio descriptivo transversal. Se incluyeron 77 pacientes por muestreo consecutivo, que consultaban por síndrome uretral agudo, realizándoseles tira, urocultivo y registro de la sintomatología. Resultados: sensibilidad = 94,3 porciento (79,5-99,0), especificidad = 78,6 porciento (62,8-89,2), valor predictivo positivo = 78,6 porciento (62,8-89,2), valor predictivo negativo = 94,3 porciento (79,5-99,0), con un nivel de confianza del 95 porciento. No se encontraron diferencias significativas con los resultados para la tira en laboratorio. Los únicos síntomas que resultaron predictores de urocultivos positivos mediante regresión logística fueron la duración del cuadro y la hematuria, y los síntomas predictores de tira positiva (esterasa leucocitaria y/o nitritos) fueron la sensibilidad hipogástrica y la duración del cuadro. Conclusiones: las tiras reactivas de orina son un buen método diagnóstico de infección urinaria en pacientes sin factores de riesgo. Su aplicación rutinaria en la consulta de Atención Primaria permitirá eliminar urocultivos innecesarios (AU)

Multiple locations of the rDNA sites in holocentric chromosomes of Rhynchospora (Cyperaceae).

Several cytogenetic studies have shown that representatives of the family Cyperaceae have holocentric chromosomes. Despite their interesting chromosome morphology, the chromosome organization has not been studied. This paper reports on the number and distribution of 18S-5.8S-26S ribosomal RNA sites by fluorescence in situ hybridization in eight Brazilian species of Rhynchospora. The signal of the rDNA probe was always localized in the telomeric regions. A high degree of variation was observed in the number of labelled sites, ranging from 4-8 in karyotypes with 2n = 10 to 30 sites in a karyotype with 50 chromosomes. It is possible that the same mechanism involved in the multiplication of these regions in organisms with monocentric chromosomes also plays a role in the polymorphism observed in holocentric chromosomes of Rhynchospora. An interesting feature of most hybridization sites was their diffuse state observed through to early metaphase. The decondensed state probably reflects the later transcription of this region during the cell cycle.