PCR: una nueva herramienta para el estudio de hongos ectomicorrícicos

PCR: a new tool for the study of ectomycorrhizal fungi. PCR (Polymerase Chain Reaction) is a simple technique that allows the specific amplification of particular regions of the genome of living organisms to facilitate their study. In the last few years, this and other complementary techniques have opened the field of the molecular mycology, whose Applications in detection, identification and c1assification of fungi are increasing every day. In this article, the first of a series dealing with the Molecular Techniques that can be used in Mycology, we explain the basic principies of both the PCR and two other complementary techniques commonly used for the molecular analysis of the amplified regions: RFLPs (Restriction Fragment Length Polymorphisms) and sequencing (determination ofthe primary structure ofthe nucleic acids).La PCR (reacción en cadena de la polimerasa) es una técnica sencilla que permite sacar copias (amplificar) de una determinada región del genoma de los seres vivos con el fin de facilitar su estudio. Esta y otras técnicas complementarias se han abierto, en los últimos años, al ámbito de la micología molecular, cuyas aplicaciones a nivel de detección, identificación y clasificación de hongos se incrementan día a día. En este primer artículo de una serie dedicada a las técnicas moleculares aplicables en Micología, se exponen los principios básicos, tanto de la PCR como de las otras dos técnicas complementarias que se utilizan habitualmente para el análisis molecular de las regiones amplificadas: los RFLPs (polimorfismos del tamaño de los fragmentos de restricción) y la secuenciación (determinación de la estructura primaria de los ácidos nucleicos)

Cómo motivar a los estudiantes de secundaria mediante actividades de ciencias atractivas y divertidas

Se presenta una propuesta de formación del profesorado llevada a cabo durante dos cursos académicos (2006/08) con la finalidad de mejorar la motivación e interés de los estudiantes hacia el aprendizaje de las ciencias. Se diseñó e implementó un curso desde la perspectiva de una ciencia comprometida, pero también amena, creativa y divertida, incluyendo actividades interactivas realizadas en colaboración con el Museo de Ciencias Príncipe Felipe, experimentos de laboratorio, textos divulgativos con enfoques CTSA (Ciencia-Tecnología-Sociedad-Ambiente), juguetes científicos, así como el aporte de experiencias provenientes de otros países europeos (Alemania, Francia y Reino Unido). Esta iniciativa, en la que han participado 80 profesores ha sido un instrumento eficaz tanto para la mejora de la motivación como para promover la formación de comunidades de práctica

Interactions between Seagrass Complexity, Hydrodynamic Flow and Biomixing Alter Food Availability for Associated Filter-Feeding Organisms

Seagrass shoots interact with hydrodynamic forces and thereby a positively or negatively influence the survival of associated species. The modification of these forces indirectly alters the physical transport and flux of edible particles within seagrass meadows, which will influence the growth and survivorship of associated filter-feeding organisms. The present work contributes to gaining insight into the mechanisms controlling the availability of resources for filter feeders inhabiting seagrass canopies, both from physical (influenced by seagrass density and patchiness) and biological (regulated by filter feeder density) perspectives. A factorial experiment was conducted in a large racetrack flume, which combined changes in hydrodynamic conditions, chlorophyll a concentration in the water and food intake rate (FIR) in a model active filter-feeding organism (the cockle). Results showed that seagrass density and patchiness modified both hydrodynamic forces and availability of resources for filter feeders. Chlorophyll a water content decreased to 50% of the initial value when densities of both seagrass shoots and cockles were high. Also, filter feeder density controlled resource availability within seagrass patches, depending on its spatial position within the racetrack flume. Under high density of filter-feeding organisms, chlorophyll a levels were lower between patches. This suggests that the pumping activity of cockles (i.e. biomixing) is an emergent key factor affecting both resource availability and FIR for filter feeders in dense canopies. Applying our results to natural conditions, we suggest the existence of a direct correlation between habitat complexity (i.e. shoot density and degree of patchiness) and filter feeders density. Fragmented and low-density patches seem to offer both greater protection from hydrodynamic forces and higher resource availability. In denser patches, however, resources are allocated mostly within the canopy, which would benefit filter feeders if they occurred at low densities, but would be limiting when filter feeder were at high densities

Progression of Doppler changes in early-onset small for gestational age fetuses. How frequent are the different progression sequences?

OBJECTIVE: To evaluate the progression of Doppler abnormalities in early-onset fetal smallness (SGA). METHODS: A total of 948 Doppler examinations of the umbilical artery (UA), middle cerebral artery (MCA) and ductus venosus (DV), belonging to 405 early-onset SGA fetuses, were studied, evaluating the sequences of Doppler progression, the interval examination-labor at which Doppler became abnormal and the cumulative sum of Doppler anomalies in relation with labor proximity. RESULTS: The most frequent sequences were that in which only the UA pulsatility index (PI) became abnormal (42.1%) and that in which an abnormal UA PI appeared first, followed by an abnormal MCA PI (24.2%). In general, 71.3% of the fetuses followed the classical progression sequence UA→MCA→DV, mostly in the early stages of growth restriction (84.1%). In addition, the UA PI was the first parameter to be affected (9 weeks before delivery), followed by the MCA PI and the DV PIV (1 and 0 weeks). Finally, the UA PI began to sum anomalies 5 weeks before delivery, while the MCA and DV did it at 3 and 1 weeks before the pregnancy ended. CONCLUSIONS: In early-onset SGA fetuses, Doppler progression tends to follow a predictable order, with sequential changes in the umbilical, cerebral and DV impedances

Somatostatin subtype-2 receptor-targeted metal-based anticancer complexes

Conjugates of a dicarba analogue of octreotide, a potent somatostatin agonist whose receptors are overexpressed on tumor cells, with [PtCl 2(dap)] (dap = 1-(carboxylic acid)-1,2-diaminoethane) (3), [(η 6-bip)Os(4-CO 2-pico)Cl] (bip = biphenyl, pico = picolinate) (4), [(η 6-p-cym)RuCl(dap)] + (p-cym = p-cymene) (5), and [(η 6-p-cym)RuCl(imidazole-CO 2H)(PPh 3)] + (6), were synthesized by using a solid-phase approach. Conjugates 3-5 readily underwent hydrolysis and DNA binding, whereas conjugate 6 was inert to ligand substitution. NMR spectroscopy and molecular dynamics calculations showed that conjugate formation does not perturb the overall peptide structure. Only 6 exhibited antiproliferative activity in human tumor cells (IC 50 = 63 ± 2 μ in MCF-7 cells and IC 50 = 26 ± 3 μ in DU-145 cells) with active participation of somatostatin receptors in cellular uptake. Similar cytotoxic activity was found in a normal cell line (IC 50 = 45 ± 2.6 μ in CHO cells), which can be attributed to a similar level of expression of somatostatin subtype-2 receptor. These studies provide new insights into the effect of receptor-binding peptide conjugation on the activity of metal-based anticancer drugs, and demonstrate the potential of such hybrid compounds to target tumor cells specifically. © 2012 American Chemical Society

Recent trends in molecular diagnostics of yeast infections : from PCR to NGS

The incidence of opportunistic yeast infections in humans has been increasing over recent years. These infections are difficult to treat and diagnose, in part due to the large number and broad diversity of species that can underlie the infection. In addition, resistance to one or several antifungal drugs in infecting strains is increasingly being reported, severely limiting therapeutic options and showcasing the need for rapid detection of the infecting agent and its drug susceptibility profile. Current methods for species and resistance identification lack satisfactory sensitivity and specificity, and often require prior culturing of the infecting agent, which delays diagnosis. Recently developed high-throughput technologies such as next generation sequencing or proteomics are opening completely new avenues for more sensitive, accurate and fast diagnosis of yeast pathogens. These approaches are the focus of intensive research, but translation into the clinics requires overcoming important challenges. In this review, we provide an overview of existing and recently emerged approaches that can be used in the identification of yeast pathogens and their drug resistance profiles. Throughout the text we highlight the advantages and disadvantages of each methodology and discuss the most promising developments in their path from bench to bedside

Persistent Currents in Small, Imperfect Hubbard Rings

We have done a study with small, imperfect Hubbard rings with exact diagonalization. The results for few-electron rings show, that the imperfection, whether localized or not, nearly always decrease, but can also \emph{increase} the persistent current, depending on the character of the imperfection and the on-site interaction. The calculations are generally in agreement with more specialized studies. In most cases the electron spin plays an important role.Comment: 6 pages, 4 figure

Kinetics of dry-batch grinding in a laboratory-scale ball mill of Sn–Ta–Nb minerals from the Penouta Mine (Spain)

This work is part of the OptimOre project funded by the European Union Horizon 2020 Research and Innovation Programme under grant agreement No 642201