Rapid spectrofluorometric screening of poly-hydroxyalkanoate-producing bacteria from microbial mats

Microbial mat ecosystems are characterized by both seasonal and diel fluctuations in several physicochemical variables, so that resident microorganisms must frequently adapt to the changing conditions of their environment. It has been pointed out that, under stress conditions, bacterial cells with higher contents of poly-hydroxyalkanoates (PHA) survive longer than those with lower PHA content. In the present study, PHA-producing strains from Ebro Delta microbial mats were selected using the Nile red dying technique and the relative accumulation of PHA was monitored during further laboratory cultivation. The number of heterotrophic isolates in trypticase soy agar (TSA) was ca. 107 colony-forming units/g microbial mat. Of these, 100 randomly chosen colonies were replicated on mineral salt agar limited in nitrogen, and Nile red was added to the medium to detect PHA. Orange fluorescence, produced upon binding of the dye to polymer granules in the cell, was detected in approximately 10% of the replicated heterotrophic isolates. The kinetics of PHA accumulation in Pseudomonas putida, and P. oleovorans were compared with those of several of the environmental isolates spectrofluorometry. PHA accumulation, measured as relative fluorescence intensity, resulted in a steady-state concentration after 48 h of incubation in all strains assayed. At 72 h, the maximum fluorescence intensity of each strain incubated with glucose and fructose was usually similar. MAT-28 strain accumulated more PHA than the other isolates. The results show that data obtained from environmental isolates can highly improve studies based on modeling-simulation programs, and that microbial mats constitute an excellent source for the isolation of PHA-producing strains with industrial applications. [Int Microbiol 2006; 9(2):95-102

Técnicas de análisis en estudios observacionales en ciencias del deporte

En este trabajo introductorio del número monográfico Análisis de datos en estudios observacionales de Ciencias del Deporte (1): Avances tecnológicos y analíticos, se realiza –desde la lógica del método cientifico y sus distintas fases- un trazado de las diversas técnicas de análisis de uso en Metodología Observacional (MO) y su importancia en el ámbito del Deporte. Se realiza una revisión en la cual los diseños observacionales condicionan la pauta de análisis, y que ilustraremos citando los principales trabajos que conforman cada uno de ellos. Se analiza el trabajo con un planteamiento de los retos propuestos para el futuro: (1) completar el mapa de análisis de datos con estudios empíricos de análisis de datos hasta ahora no llevados a cabo; (2) realizar avances en las propias técnicas de análisis, poniendo en relación aquéllas que admiten complementariedad de objetivos; (3) contribuir al desarrollo tecnológico e informático, que en sí mismo es un importante incentivo para avanzar en la creación de plataformas informáticas; (4) aprovechar la importancia de la fuerza y la consistencia de los mixed-methods

Real-time detection of riboflavin production by Lactobacillus plantarum strains and tracking of their gastrointestinal survival and functionality in vitro and in vivo using mCherry labeling

Some strains of lactic acid bacteria (LAB) produce riboflavin, a water-soluble vitamin of the B complex, essential for human beings. Here, we have evaluated riboflavin (B2 vitamin) production by five Lactobacillus plantarum strains isolated from chicha, a traditional maize-based fermented alcoholic beverage from north-western Argentina and their isogenic riboflavin-overproducing derivatives previously selected using roseoflavin. A direct fluorescence spectroscopic detection method to quantify riboflavin production in bacterial culture supernatants has been tested. Comparison of the efficiency for riboflavin fluorescence quantification with and without prior HPLC fractionation showed that the developed method is a rapid and easy test for selection of B2 vitamin-producing strains. In addition, it can be used for quantitative detection of the vitamin production in real time during bacterial growth. On the basis of this and previous analyses, the L. plantarum M5MA1-B2 riboflavin overproducer was selected for in vitro and in vivo studies after being fluorescently labeled by transfer of the pRCR12 plasmid, which encodes the mCherry protein. The labeling did not affect negatively the growth, the riboflavin production nor the adhesion of the strain to Caco-2 cells. Thus, L. plantarum M5MA1-B2[pRCR12] was evaluated for its survival under digestive tract stresses in the presence of microbiota in the dynamic multistage BFBL gut model and in a murine model. After exposure to both models, M5MA1-B2[pRCR12] could be recovered and detected by the pink color of the colonies. The results indicated a satisfactory resistance of the strain to gastric and intestinal stress conditions but a low colonization capability observed both in vitro and in vivo. Overall, L. plantarum M5MA1-B2 could be proposed as a probiotic strain for the development of functional foods.Fil: Mohedano, Mari Luz. Consejo Superior de Investigaciones Científicas. Centro de Investigaciones Biológicas; EspañaFil: Hernández Recio, Sara. Consejo Superior de Investigaciones Científicas. Centro de Investigaciones Biológicas; EspañaFil: Yépez, Alba. Universidad de Valencia; EspañaFil: Requena, Teresa. Consejo Superior de Investigaciones Científicas. Instituto de Investigación en Ciencias de la Alimentación; EspañaFil: Martínez Cuesta, M. Carmen. Consejo Superior de Investigaciones Científicas. Instituto de Investigación en Ciencias de la Alimentación; EspañaFil: Peláez, Carmen. Consejo Superior de Investigaciones Científicas. Instituto de Investigación en Ciencias de la Alimentación; EspañaFil: Russo, Pasquale. Università di Foggia; ItaliaFil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Spano, Giuseppe. Università di Foggia; ItaliaFil: Aznar, Rosa. Universidad de Valencia; España. Consejo Superior de Investigaciones Científicas. Instituto de Agroquímica y Tecnología de Alimentos; EspañaFil: López, Paloma. Consejo Superior de Investigaciones Científicas. Centro de Investigaciones Biológicas; Españ

Espondilitis tuberculosa no es una metástasis vertebral: diagnóstico diferencial y tratamiento quirúrgico. A propósito de un caso

Presentamos el caso de una paciente con dorsalgia y clínica neurológica de varios meses de evolución que ante las pruebas de imagen fue erróneamente diagnosticada de metástasis vertebral sin confirmación previa con biopsia. El deterioro progresivo neurológico y las nuevas pruebas de imagen confirmaron el diagnóstico de tuberculosis vertebral. La paciente fue tratada mediante curetaje, desbridamiento, fusión intersomática y osteosíntesis anterior además del tratamiento médico. Hubo una recuperación neurológica de la función sensitiva, motora y esfinteriana prácticamente completa al mes de la intervención. Tras 20 meses de evolución la paciente está asintomática sin evidencia de progresión de la enfermedadWe report a patient with back pain and neurological symptoms several months of evolution to the test image was wrongly diagnosed with spinal metastases without prior confirmation with biopsy. The progressive deterioration of neurological and new imaging confirmed the diagnosis of spinal tuberculosis. The patient was treated by curettage, debridement, anterior interbody fusion and internal fixation in addition to medical treatment. There neurological recovery of sensory function, motor and sphincter almost complete month after the intervention. After 20 months of evolution, the patient is asymptomatic without evidence of disease progressio