Biodiversidad bacteriana marina: nuevos taxones cultivables

Se presenta un estudio sobre la diversidad cultivable del ambiente marino empleando técnicas de cultivo tradicionales e identificación mediante secuencia parcial (aproximadamente 1000 bases) del gen ribosomal de la subunidad menor de aislados bacterianos quimioheterótrofos obtenidos a partir de agua del Mar Mediterráneo y ostra cultivada. Dado el enfoque taxonómico del estudio, las cepas consideradas de interés han sido aquellas cuya secuencia del gen 16S rRNA presentaban una semejanza menor del 98,0% con las de las cepas tipo de las especies más cercanas. Las bacterias marinas seleccionadas por su novedad taxonómica se han sometido a una caracterización polifásica para su descripción y propuesta como nuevos taxones (géneros y especies). La caracterización fenotípica se ha realizado mediante determinación del perfil de actividades enzimáticas y metabólicas, caracteres fisiológicos (rangos de temperatura y salinidad, requerimientos iónicos específicos, relaciones con el oxígeno), caracteres nutricionales (fuentes de carbono, nitrógeno y energía, requerimiento de factores de crecimiento), caracteres morfológicos celulares y coloniales, movilidad (mediante microscopía óptica y electrónica), pigmentos, etc. Se ha complementado mediante sistemas multiprueba (galerías API y Biolog) y con el análisis de proteínas por espectrometría de masas (MALDI-TOF MS) con el fin de permitir una rápida diferenciación de los taxones. Además, se ha realizado la caracterización quimiotaxonómica, que incluye el perfil de ácidos grasos celulares (determinación por cromatografía de gases mediante el sistema MIDI), la composición de lípidos polares mayoritarios mediante cromatografía en capa fina (TLC) y el contenido en quinonas isoprenoides por cromatografía líquida de alta presión (HPLC). La caracterización genotípica ha incluido la determinación del contenido en bases guanina y citosina (G+C) del DNA. Además, se ha completado la secuencia del gen 16S rRNA (>1400 nucleótidos). Con las secuencias obtenidas se han elaborado los estudios filogenéticos basados en la comparación con las secuencias génicas de las especies tipo y representativas de los géneros más cercanos, permitiendo la reconstrucción filogenética empleando los algoritmos NJ, MP y ML disponibles en el paquete informático ARB. En algunos casos y con el fin de profundizar y resolver mejor las relaciones filogenéticas, se han analizado otros genes esenciales o ‘housekeeping’ (gyrB, recA, pyrH, …) tanto de forma individual como concatenados. Cuando la secuencia del gen 16S rRNA no bastaba para delimitar especies, se ha determinado el valor ANI (identidad nucleotídica media). Esta es una técnica de reciente aplicación en taxonomía bacteriana para la comparación de parejas de genomas, y que da la identidad de secuencia promedio que muestran todos los genes ortólogos compartidos. Este estudio ha permitido identificar a las proteobacterias como las bacterias quimioheterótrofas cultivables más abundantes en el agua de mar del Mediterráneo y confirmar la dominancia del género Vibrio, mientras que las bacterias pertenecientes a otros filos son de más difícil recuperación. La selección de las cepas de interés taxonómico y la caracterización taxonómica de éstas ha permitido reconocer siete nuevos taxones dentro de la clase Alphaproteobacteria y la descripción formal de dos nuevos géneros (Actibacterium y Phaeomarinomonas) y cinco nuevas especies (Actibacterium mucosum, Phaeomarinomonas mediterranea, Phaeomarinomonas costicola, Roseovarius litoralis y Tropicibacter multivorans). Del mismo modo, se han reconocido y descrito cuatro nuevas especies dentro de la clase Gammaproteobacteria, Haliea mediterranea, Photobacterium aphoticum, Vibrio aestivus y Vibrio quintilis. Además, se ha descrito un nuevo género y dos nuevas especies pertenecientes al filo Bacteroidetes, Euzebyella saccharophila, género nuevo con una sola especie, y Marinifilum flexuosus. El análisis comparativo genómico, utilizando parámetros no dependientes de anotación (ANIb, ANIm y TETRA) sobre datos de secuenciación masiva al azar, ha permitido delimitar especies de acuerdo con los umbrales propuestos, de modo satisfactorio. Este estudio ha puesto de manifiesto la existencia de taxones no descritos entre las poblaciones bacterianas fácilmente cultivables y procedentes de nuestro entorno inmediato

Ex vivo experimental model for percutaneous vertebroplasty: microCT utility

The aim of this study was to develop an ex vivo experimental animal model for percutaneous vertebroplasty, for further application in vivo to test novel bone injectable cements

The Efficiency of Health Services in Spain Based on Data Envelopment Analysis (DEA). The Singularity of Health Efficiency

Objectives: To study the comparative efficiency of the regional health services in Spain through DEA and shed light on the orientations of health policies to improve the public perception of health services as well as the participation of citizens in formulating health Policies and setting priorities. Study design: Comparative analysis of the efficiency of the health services of the different regions of Spain through DEA. Methods: It uses a non-oriented approach in which efficiency is sought via an increase of the variables considered desirable, the natural unified health efficiency is employed for this aim, while the managerial unified is utilised for a decrease of the undesirable variables. The two are related through the so-called managerial natural unified health efficiency. Results: Orientations of the health policy are indicated which each of the health systems analysed must follow in order to improve its efficiency. There are two types of possible adjustments to be carried out: natural adjustments which require the increase of the resources used, and managerial adjustments which require the decrease of the resources used. While the first only require the increase of the inputs, the second involve the modification of managerial policies which improve the results. The study enables a grouping of the health systems into four blocks in which the efficiencies can be attained through natural y/o managerial adjustments. Conclusion: The lack of efficiency can always be solved through the increase of the budget provision and only in some cases via the improvement of resource management policies

Returning to Nature for the Design of Sorptive Phases in Solid-Phase Microextraction

Green analytical chemistry principles aim to minimize the negative impact of analytical procedures in the environment, which can be considered both at close (to ensure the safety of the analysts) and global (to conserve our natural resources) levels. These principles suggest, among other guidelines, the reduction/minimization of the sample treatment and the use of renewable sources when possible. The first aspect is largely fulfilled by microextraction, which is considered to be among the greenest sample treatment techniques. The second consideration is attainable if natural products are used as raw materials for the preparation of new extraction phases. This strategy is in line with the change in our production system, which is being gradually moved from a linear model (take–make–dispose) to a circular one (including reusing and recycling as key terms). This article reviews the potential of natural products as sorbents in extraction and microextraction techniques from the synergic perspectives of two research groups working on the topic. The article covers the use of unmodified natural materials and the modified ones (although the latter has a less green character) to draw a general picture of the usefulness of the materials

Development of a sheep vertebroplasty model for bioceramic materials assessment

Development of a sheep vertebroplasty model for bioceramic materials assessment Sheep has been widely used as an animal orthopaedic model. Although several studies report anatomic and biomechanical similarities as well as distinctions of ovine lumbar vertebrae when compared to human’s, only a few studies describe its actual use as a vertebroplasty model. Due to distinct anatomic features, sheep lumbar vertebrae pose a challenge when developing a minimally invasive procedure for vertebroplasty material testing, under conditions meant to be the most similar to clinical procedure. The present work describes the development of an appropriate surgical percutaneous vertebroplasty model in the lumbar spine of sheep, applicable in vivo, that minimizes the risk of post-surgical complications. This model was mechanically evaluated ex-vivo regarding its safety, and used to evaluate the injectability and radiopacity of two new bioceramic materials when compared to a commercial bioceramic bone substitute (Cerament™ SpineSupport). Microtomography techniques helped in the development of the model and results assessment. Under fluoroscopic guidance, a defect was created through a bilateral modified parapedicular access in the cranial hemivertebrae of 30 sheep lumbar vertebrae (L4, L5 and L6). The manually drilled defect had an average volume of 1209 ±226 mm3 and allowed the novel materials injection through a standardized injection cannula placed in one of the entrance points. Adequate defect filling was observed with all tested materials. No mechanical failure was observed under loads higher than the physiological

Chryseobacterium potabilaquae sp. nov., Chryseobacterium aquaeductus sp. nov. and Chryseobacterium fistulae sp. nov., from drinking water systems

A polyphasic taxonomic study was conducted on three strains isolated from drinking water systems that had previously been deposited as Chryseobacterium species at the Spanish Type Culture Collection in order to complete their classification. Strains CECT 9293T, CECT 9390T and CECT 9393T were isolated from sites in Barcelona, Spain, in the framework of a project aimed at generating the first MALDI-TOF database specific for bacteria present in water for human consumption. Their partial 16S rRNA sequences showed that their closest relatives among the type strains of Chryseobacterium exhibited 98 % similarity or less, supporting their taxonomic novelty. At the same time, comparison between them revealed that strains CECT 9293T and CECT 9393T could perhaps be related at the species level as they shared 99.5 % similarity. However, whole genome sequencing was performed and the subsequent calculation of relatedness indices, average nucleotide identity and estimated DNA-DNA hybridization, ruled out that possibility and confirmed instead that each of the strains should be considered a separate species in the genus Chryseobacterium. Having clarified their status, we also performed phylogenomic analyses and searched for possible environmental or non-type material sequences that could be related to any of them at the species level. In parallel, the strains were characterized phenotypically and compared to their closest relatives to determine diagnostic traits to support their formal proposal. The proposed species are Chryseobacterium potabilaquae sp. nov. with the type strain CECT 9293T (=LMG 32084T), Chryseobacterium aquaeductus sp. nov. with the type strain CECT 9390T (=LMG 32085T) and Chryseobacterium fistulae sp. nov. with the type strain CECT 9393T (=LMG 32086T)

Mesonia oceanica sp. Nov., isolated from oceans during the tara oceans expedition, with a preference for mesopelagic waters

Strain ISS653T, isolated from Atlantic seawater, is a yellow pigmented, non-motile, Gram-reaction-negative rod-shaped bac-terium, strictly aerobic and chemoorganotrophic, slightly halophilic (1-15% NaCl) and mesophilic (4-37 °C), oxidase-and catalase-positive and proteolytic. Its major cellular fatty acids are iso-C15:0, iso-C15:0 2-OH, and iso-C17:0 3-OH; the major identified phospholipid is phosphatidylethanolamine and the major respiratory quinone is MK6. Genome size is 4.28 Mbp and DNA G+C content is 34.9 mol%. 16S rRNA gene sequence similarity places the strain among members of the family Flavobacteriaceae, with the type strains of Mesonia phycicola (93.2%), Salegentibacter mishustinae (93.1%) and Mesonia mobilis (92.9%) as closest relatives. Average amino acid identity (AAI) and average nucleotide identity (ANI) indices show highest values with M. mobilis (81% AAI; 78.9% ANI), M. phycicola (76% AAI; 76.3% ANI), Mesonia maritima (72% AAI, 74.9% ANI), Mesonia hippocampi (64% AAI, 70.8% ANI) and Mesonia algae (68% AAI; 72.2% ANI). Phylogenomic analysis using the Up-to-date-Bacterial Core Gene set (UBCG) merges strain ISS653T in a clade with species of the genus Mesonia. We conclude that strain ISS653T represents a novel species of the genus Mesonia for which we propose the name Mesonia oceanica sp. nov., and strain ISS653T (=CECT 9532T=LMG 31236T) as the type strain. A second strain of the species, ISS1889 (=CECT 30008) was isolated from Pacific Ocean seawater. Data obtained throughout the Tara oceans expedition indicate that the species is more abundant in the mesopelagic dark ocean than in the photic layer and it is more frequent in the South Pacific, Indian and North Atlantic oceans

Coliphages as model organisms in the characterization and management of water resources

Two groups of bacteriophages that infect Escherichia coli, somatic and F-specific coliphages, have been used in academia as both fecal and viral indicators for many years. Regulatory authorities in different parts of the world are beginning to consider coliphages as indicators of water quality in a range of settings. However, issues such as their potential replication in natural water environments, the cumbersome detection and enumeration methods, a lack of definition concerning which of the two groups should be included in future regulations, and the lack of a clear correlation between coliphages and human viruses and health risks in different water settings remain controversial. This review attempts to shed some light on these contentious issues. The conclusions are that: 1) supposing that they can replicate in some natural water settings, the contribution of coliphages replicated outside the gut will not affect the numbers contributed by fecal pollution and detected by strains recommended for standardized methods; 2) there are easy, fast, and cost-effective methods that can be used in routine laboratories after a little training; 3) perhaps the best option is to determine both groups in a single step; and 4) the low correlation of coliphages with human viruses and health risks is no worse than the correlation between different human viruses

Synthesis and characterization of nano Fe and Mn (hydr)oxides to be used as natural sorbents and micronutrient fertilizers

Fe and Mn (hydr)oxides are widely used as contaminant sorbents in water/wastewater systems but their potential use as micronutrient fertilizers is still poorly known. In this research, four nano-metal (hydr)oxides (amorphous Mn oxide (AMO), Fe-Mn binary oxide (FMBO), two-line ferrihydrite (2L-Fh) and goethite) were successfully synthesized and completely characterized (infrared and Mössbauer spectroscopy, X-ray diffraction particle size, specific surface area, point of zero charge). AMO, FMBO and 2L-Fh were introduced to interact with AgNO3 (20.0 µM) and TlNO3 (100.0 µM) diluted solutions for three days to check their potential capability as potential Ag+ and Tl+ adsorbents. AMO and FMBO (4% w/w) were tested as nanofertilizers by arranging a hydroponic bioassay for 35 days on white lupin culture as a Mn-hyperaccumulator plant model. AMO structure was identified as an amorphous mixture of Mn oxides while FMBO was an Fe dopped birnessite. Both materials were efficient in extracting Ag+ and Tl+ although large Mn concentration was released from FMBO to the solutions. AMO and FMBO promoted Fe and Mn nutrition in plants. Synthetic iron chelate (Fe-EDDHA), present in the nutrient dissolution, could be adsorbed onto AMO surface by producing Fe and Mn accumulation in roots and increasing Mn uptake rate without toxicity symptoms. Therefore, AMO and FMBO not only demonstrated their efficiency as adsorbents, but also displayed they would be promising nanomaterials as micronutrient fertilizer