A nearby transiting rocky exoplanet that is suitable for atmospheric investigation.

Spectroscopy of transiting exoplanets can be used to investigate their atmospheric properties and habitability. Combining radial velocity (RV) and transit data provides additional information on exoplanet physical properties. We detect a transiting rocky planet with an orbital period of 1.467 days around the nearby red dwarf star Gliese 486. The planet Gliese 486 b is 2.81 Earth masses and 1.31 Earth radii, with uncertainties of 5%, as determined from RV data and photometric light curves. The host star is at a distance of ~8.1 parsecs, has a J-band magnitude of ~7.2, and is observable from both hemispheres of Earth. On the basis of these properties and the planet's short orbital period and high equilibrium temperature, we show that this terrestrial planet is suitable for emission and transit spectroscopy.

A giant exoplanet orbiting a very-low-mass star challenges planet formation models.

Surveys have shown that super-Earth and Neptune-mass exoplanets are more frequent than gas giants around low-mass stars, as predicted by the core accretion theory of planet formation. We report the discovery of a giant planet around the very-low-mass star GJ 3512, as determined by optical and near-infrared radial-velocity observations. The planet has a minimum mass of 0.46 Jupiter masses, very high for such a small host star, and an eccentric 204-day orbit. Dynamical models show that the high eccentricity is most likely due to planet-planet interactions. We use simulations to demonstrate that the GJ 3512 planetary system challenges generally accepted formation theories, and that it puts constraints on the planet accretion and migration rates. Disk instabilities may be more efficient in forming planets than previously thought.

A candidate super-Earth planet orbiting near the snow line of Barnard's star.

Barnard's star is a red dwarf, and has the largest proper motion (apparent motion across the sky) of all known stars. At a distance of 1.8 parsecs1, it is the closest single star to the Sun; only the three stars in the α Centauri system are closer. Barnard's star is also among the least magnetically active red dwarfs known2,3 and has an estimated age older than the Solar System. Its properties make it a prime target for planetary searches; various techniques with different sensitivity limits have been used previously, including radial-velocity imaging4-6, astrometry7,8 and direct imaging9, but all ultimately led to negative or null results. Here we combine numerous measurements from high-precision radial-velocity instruments, revealing the presence of a low-amplitude periodic signal with a period of 233 days. Independent photometric and spectroscopic monitoring, as well as an analysis of instrumental systematic effects, suggest that this signal is best explained as arising from a planetary companion. The candidate planet around Barnard's star is a cold super-Earth, with a minimum mass of 3.2 times that of Earth, orbiting near its snow line (the minimum distance from the star at which volatile compounds could condense). The combination of all radial-velocity datasets spanning 20 years of measurements additionally reveals a long-term modulation that could arise from a stellar magnetic-activity cycle or from a more distant planetary object. Because of its proximity to the Sun, the candidate planet has a maximum angular separation of 220 milliarcseconds from Barnard's star, making it an excellent target for direct imaging and astrometric observations in the future.

Diversity of culturable halophilic archaea isolated from Rambla Salada, Murcia (Spain).

We have studied the diversity of culturable halophilic Archaea at Rambla Salada, Murcia (south-eastern Spain). We made 8 samplings at different places in this habitat during the years 2006 and 2007 and isolated a total of 49 strains, which were identified by means of phenotypic tests and the hypervariable V1-V3 region of the 16S rRNA gene sequences (around 500 bp). The ribosomal data showed that the isolates belonged to 12 genera within the Halobacteriaceae family, with Haloferax and Natrinema being the most abundant. Five strains showed less than 97% sequence identity with validly described species and may well represent new taxa. All the strains grew best with around 25% w/v salts, required high concentrations of NaCl and magnesium and produced red to pink colonies. They were facultative anaerobes with both respiratory and fermentative metabolisms. The diversity of the archaeal community was analysed with the MOTHUR package. We identified 14 OTUs at the 3% genetic distance level and found quite high diversity. Rarefaction curves of richness estimators and diversity indices demonstrated that our collection of isolates represented the archaeal community at Rambla Salada that can be isolated under the conditions used in this work. This is the first report to be published on the culturable archaea at Rambla Salada, an area of considerable ecological interest.

Aplicaciones del exopolisacárido producido por la cepa HK30 de Halomonas nitroreducens en la industria farmacéutica / Pharmaceutical applications of the exopolysaccharides produced by Halomonas nitroreducens strain HK30

INTRODUCCIÓN: Una de las líneas de investigación que desarrolla el Grupo Exopolisacáridos Microbianos (BIO 188) es el aislamiento y caracterización de nuevos microorganismos halófilos productores de EPSs con propiedades físicas y químicas competitivas con los ya existentes en la industria. De estos estudios destaca el polímero V2-7 (Halomonas eurihalina F2-7) que origina geles transparentes1, el maurano(H. maura S-30) cuya viscosidad compite con la del xantano2 y los EPSs producidos por Salipigermucescens, Halomonas. anticariensis, H. ventosae, Idiomarina fontislapidosi, I. ramblicola y Alteromonas hispanica que emulsionan diferentes compuestos orgánicos y pueden actuar como biodetoxificadores 3,4. Además, estos polímeros tienen sulfatos en su composición que es una característica inusual e interesante para su aplicación en Medicina y el producido por S. mucescens contiene un carbohidrato llamado fucosa, con interesantes aplicaciones en cosmética y que resulta caro de obtener por síntesis química 5. El grupo de investigación tiene colaboraciones con empresas del sector alimentario, farmacéutico y cosmético para aplicar las propiedades funcionales de sus polisacáridos en estas áreas. OBJETIVO: La búsqueda y selección de bacterias productoras de exopolisacáridos de ambientes hipersalinos situados en Marruecos con propiedades interesantes para la industria(AU)

METODOLOGÍA: Cepas bacterianas y condiciones de cultivo. Las cepas fueron aisladas de ambientes hipersalinos situados en Marruecos (suelos y aguas hipersalinos, alimentos en salazón y las raíces de las plantas marinas). Para producir los EPSs las bacterias se cultivaron en medio MY 7,5 % p/v de sales y se incubaron a 32ºC en agitación (100 rpm) durante 5 días. Producción de exopolisacáridos. Los exopolisacáridos se extrajeron de acuerdo con la metodología descrita por Quesada y col. 6 Caracterización química y determinación de la masa molecular. El contenido en carbohidratos, proteínas, ácidos urónicos, restos acetilos, iones sulfato y fosfato, así como la composición en monosacáridos y la masa molecular de los EPSs purificados se analizó siguiendo la metodología previamente descrita en nuestros trabajos 4. Caracterización física. El estudio de las características reológicas y actividad emulgente se realizó siguiendo la metodología descrita por Mata y col. 3. Estudio de la participación de los EPS en la formación de biofilms. Se hizo mediante tinción con cristal violeta en placas microtiter tras 40 horas de incubación en medios MY y MM al 7,5% (p/v) de NaCl7. Determinación de la actividad floculante. Se prepararon soluciones de caolín y se mezclaron con diferentes concentraciones de EPS 8,9. CONCLUSIÓN /DISCUSIÓN: A partir de una colección de 120 cepas se han seleccionado las 26 mejores productoras de EPSs, que han sido identificadas taxonómicamente. Tras un primer análisis de la productividad y características físicas y químicas de los EPSs, se ha elegido el polímero producido por la cepa HK30 para llevar a cabo un estudio más completo. La cepa HK30, por su mayor rendimiento en la producción de un polímero con actividad viscosizante y emulgente, se considera un excelente candidato de interés biotecnológico con aplicaciones en la industria farmacéutica(AU)

The Microbial Exopolysaccharide Research Group (BIO 188) has been carrying out a wide search aimed at isolating and characterizing exopolysac charides produced by halophilic microorganisms with different physical and chemical properties of interest to industry. As a result of these studies, we selected and characterized the polymer V2-7 (Halomonas eurihalina F2-7) that has emulsifying activity and jellifying properties at acid pH1; the mauran, which has a viscosifying activity similar to that of xanthan gum2 and the EPSs produced by Salipiger mucosus, Halomonas anticariensis, H.ventosae, Idiomarina fontislapidosi, I. ramblicola and Alteromonas hispanica that emulsify different organic compounds 3,4. In addition, all of these polymers have sulphate groups in their composition, anunusual and interesting feature for their application in medicine. More over, the fucose-rich EPS of Salipiger mucosus has applications in the fields of medicine and cosmetics. The chemical orenzymatic hydrolysis of fucose-rich polysaccharides offers a new efficient way to process fucose 5. The Research Group BIO 188 has established collaborations with several companies related to the food, pharmaceutical and cosmetics industries in order to test the functional properties of our halophilicexopolysaccharides in these areas. AIM: Searching and selection of exopolysaccharide-producing bacteria from hypersaline environments located in Morocco with interesting properties to industry(AU)

MATERIAL AND METHODS: Bacterial strains and culture conditions. The strains were isolated from hypersaline environments in Morocco. Bacteria were cultured in MY with 7.5% (w/v) of salts and incubated at 32 °C with shaking(100 rpm) for 5 days. Production of exopolysaccharides. The exopolysaccharides were isolated according to the methodology described by Quesada et al. 6 Chemical characterization and molecular weight determination. The content of carbohydrates, proteins, uronic acids, acetyl residues, sulphates, phosphates, monosaccharide composition, and molecular weight of purified EPSs were analyzed following the methodology previously described [4]. Physical characterization. The study of the rheological properties and emulsifying activity was carried out following the methodology described by Mata et al. 3 Production of biofilms. The production of biofilms were tested by crystal violet staining in microtiter plates after 40 hours incubation in the media MM and MY 7.5% (w/v) 7. Determination of flocculating activity. Kaolin solutions were prepared and mixed with different concentrations of EPS8,9(AU)

Aislamiento de cepas del género Halomonas con interés biotecnológico en Rambla Salada (Murcia) / Isolaton of strains of the genus Halomonas with biotechnologycal interest from Rambla Salada (Murcia)

El género Halomonas es uno de los taxones bacterianos más representativos dentro de las bacterias halófilas moderadas. Se encuentra incluido en el Phyllum Proteobacteria, clase Gamma-Proteobacteria, familia Halomonadaceae1. Son en su mayoría de bacterias halófilas moderadas, con un requerimiento de NaCl para su óptimo crecimiento que oscila entre un 3-15% (p/v). Las especies de esta familia han demostrado ser un grupo de microorganismos extremófilos con un gran potencial biotecnológico, por la producción de solutos compatibles que les confiere capacidad para estabilizar y proteger enzimas así como aplicaciones en tecnología enzimática, en la industria cosmética y dermofarmacia, medicina y agricultura. Estas especies son capaces de producir también compuestos extracelulares como exopolisacáridos y enzimas extracelulares. Los primeros tienen gran interés industrial debido a sus propiedades viscosizantes, estabilizantes, emulgentes y formadoras de geles. Nuestro grupo de investigación a lo largo de estos años ha caracterizado una decena de estos polímeros destacando los de H. eurihalina y H. maura por sus propiedades viscosizantes y emulgentes 2,3 y los de H. stenophila por sus propiedades antitumorales 4. En cuanto a las enzimas extracelulares, tales como lipasas y amilasas, se mantienen estables en un amplio rango de concentraciones salinas y proporcionan así nuevas posibilidades en los procesos biocatalíticos. Otras aplicaciones biotecnológicas son la producción de polihidroxialcanoatos así como la degradación de compuestos tóxicos. Debido al gran interés biotecnológico de las bacterias halófilas moderadas, nuestro grupo de investigación lleva a cabo un estudio de biodiversidad de microorganismos halófilos en Rambla Salada (Murcia) con el fin de aislar nuevas especies de Halomonas productoras de compuestos de aplicación industrial y/o biotecnológica(AU)

Se han realizado cuatro muestreos durante dos años en Rambla Salada (Murcia, España). Las muestras han sido procesadas mediante las técnicas de microbiología clásicas y las bacterias aisladas han sido caracterizadas fenotípica y filogenéticamente. Las cepas pertenecientes al género Halomonas se sembraron en los medios adecuados para estudiar cada una de las funciones biológicas, y se seleccionaron aquellas cepas que dieron una actividad positiva. Se han aislado 164 cepas del género Halomonas, algunas de ellas con actividad lipasa, proteinasa y/odexosirribonucleasa y casi todas son productoras de exopolisacaridos. La presencia de estas cepas conactividad positiva para determinadas funciones biológicas con interés industrial y biotecnológico ponen de manifiesto la necesidad de seguir investigando en este sentido(AU)

The genus Halomonas is one of the most representative taxa amongst the moderately halophilicbacteria. This genus is included into the family Halomonadaceae, class Gamma-Proteobacteria, Phyllum Proteobacteria1. It requires NaCl concentrations 3-15% w/v for optimum growth. Halomonas species have aroused interest amongst biotechnologists because of their ability to accumulate organic compatible solutes which provide stability and protection of enzymes and other molecules and have interest in enzymatic technology, cosmetic, medicine and agriculture. They also produce extracellular compounds, such as exoenzymes and exopolysaccharides (EPS). The extracellular enzymes, such as lipase and amylase, are stable within a wide salt concentration range; this property is important in biocatalytic processes. Other biotechnological applications of the Halomonas species are the production of polyhydroxyalkanoates and the degradation of aromatic compounds. The halophilic EPS are commercially valuable products because of their biotechnology applications as viscosifying, stabilizers and gelling agents. Our research group has characterized to date tenexopolysaccharides-producing halophilic species. Two of them, H. eurihalina and H. maura produce polymers with viscosifying and emulsifying properties 2,3 and H. stenophila synthesizes and EPS with antitumoral properties 4. Isolate new species of the genus Halomonas with industrial and/or medical applications from Rambla Salada (Murcia, Spain)(AU)

Samples of saline soils, sediments and waters were taken periodically from Rambla Salada (Murcia, Spain) along two years. The samples were processed by classical methods and the isolated strains were identified by mean of phenotypic and phylogenetic techniques. The species belonging to the genus Halomonas were analyzed in order to find compounds of biotechnological interest. We have isolated 164 strains of the genus Halomonas. Some of them have lipases protease and/ordeoxyribonuclease activities and most of them are exopolysaccharide-producing bacteria. The results presented in this work show that extreme environments, such as Rambla Salada, constitute anunexplorable resource of discovering new bacteria and biomolecules(AU)

Characterization of exopolysaccharides produced by three moderately halophilic bacteria belonging to the family Alteromonadaceae.

AIMS: To study the exopolysaccharides (EPSs) produced by three novel moderately halophilic species belonging to the family Alteromonadaceae to optimize EPS yields, characterize their physical and chemical properties and evaluate possible biotechnological applications for these polymers. METHODS AND RESULTS: EPSs synthesized by Idiomarina fontislapidosi F32(T), Idiomarina ramblicola R22(T) and Alteromonas hispanica F23(T) were collected and analysed under optimum conditions: MY medium supplemented with 7.5% (w/v) salts; 32 degrees C; and 1% (w/v) glucose. Polymers were synthesized mainly during the early stationary growth phase with yields ranging from 1 to 1.5 g l(-1). The Idiomarina species each produced an anionic EPS composed mainly of glucose, mannose and galactose. A. hispanica synthesized an anionic EPS composed mainly of glucose, mannose and xylose. Solutions of all the polymers were low in viscosity and pseudoplastic in their behaviour. They showed emulsifying activity and the capacity to bind some metals. CONCLUSIONS: The Alteromonadaceae species studied in this work produced EPSs with physical and chemical properties different from those produced by other halophilic and nonhalophilic bacteria, suggesting that the wide diversity of micro-organisms being encountered nowadays in hypersaline environments offers enormous potential resources for biotechnological applications. SIGNIFICANCE AND IMPACT OF THE STUDY: We have optimized the EPS production and analysed new biopolymers produced by some recently described, moderately halophilic bacteria. These biopolymers are chemically and physically different from others already in use in biotechnology and offer hopes for new applications, especially in the case of A. hispanica, which may prove to be a viable source of xylo-oligosaccharides.

Halomonas maura sp. nov., a novel moderately halophilic, exopolysaccharide-producing bacterium.

Four moderately halophilic, exopolysaccharide-producing bacterial strains isolated from soil samples collected from a saltern at Asilah (Morocco) are reported. These four strains were initially considered to belong to the genus Halomonas. Their DNA G+C contents varied between 62.2 and 64.1 mol %. DNA-DNA hybridization revealed a considerable degree of DNA-DNA similarity amongst all four strains (75.5-80.8%). Nevertheless, similarity with the reference strains of phylogenetically close relatives was lower than 40%. 16S rRNA gene sequences were compared with those of other species of Halomonas and other gram-negative bacteria and they were sufficiently distinct phylogenetically from other recognized Halomonas species to warrant their designation as a novel species. The name Halomonas maura sp. nov. is therefore proposed, with strain S-31T (= CECT 5298T= DSM 13445T) as the type strain. The fatty acid composition of strain S-31T revealed the presence of 18:1omega7c, 16:1omega7c/2-OH i15:0 and 16:0 as the major components. Growth rate analysis showed that strain S-31T had specific cationic requirements for Na+ and Mg2+.

Discovery of young, isolated planetary mass objects in the final sigma Orionis star cluster.

We present the discovery by optical and near-infrared imaging of an extremely red, low-luminosity population of isolated objects in the young, nearby stellar cluster around the multiple, massive star final sigma Orionis. The proximity (352 parsecs), youth (1 million to 5 million years), and low internal extinction make this cluster an ideal site to explore the substellar domain from the hydrogen mass limit down to a few Jupiter masses. Optical and near-infrared low-resolution spectroscopy of three of these objects confirms the very cool spectral energy distribution (atmospheric effective temperatures of 1700 to 2200 kelvin) expected for cluster members with masses in the range 5 to 15 times that of Jupiter. Like the planets of the solar system, these objects are unable to sustain stable nuclear burning in their interiors, but in contrast they are not bound to stars. This new kind of isolated giant planet, which apparently forms on time scales of less than a few million years, offers a challenge to our understanding of the formation processes of planetary mass objects.

Decay of the GRB 990123 optical afterglow: implications for the fireball model

Broad-band (ultraviolet to near-infrared) observations of the intense gamma ray burst GRB 990123 started approximately 8.5 hours after the event and continued until 18 February 1999. When combined with other data, in particular from the Robotic Telescope and Transient Source Experiment (ROTSE) and the Hubble Space Telescope (HST), evidence emerges for a smoothly declining light curve, suggesting some color dependence that could be related to a cooling break passing the ultraviolet-optical band at about 1 day after the high-energy event. The steeper decline rate seen after 1.5 to 2 days may be evidence for a collimated jet pointing toward the observer.

[Effect of nutritional conditions on the viscosity and emulsifying capacity of V2-7 biopolymer from Volcaniella eurihalina]. / Efecto de las condiciones nutricionales sobre la viscosidad y capacidad emulgente del biopolímero V2-7 de Volcaniella eurihalina.

Volcaniella eurihalina is a moderately halophilic bacterium able to produce an exopolysaccharide (EPS) under different culture conditions. Rheological behavior of 1% EPS solutions varied depending on the conditions under which EPS were produced. The maximum viscosity was reached when maltose was used as carbon source. Limitations of phosphorus and sulfur also increased its viscosity power. On the other hand, the addition of residual oil products to the culture medium enhanced the production of this biosurfactant polymer.

[Rapid differentiation of the 0:3 and 0:9 serovars of Yersinia enterocolitica by certain bacteriophages]. / Différenciation rapide des sérovars O:3 et O:9 de Yersinia enterocolitica par certains bactériophages.

The sensitivity of some phenotypes of Yersinia to 7 phages isolated from lysogenic strains of Y. frederiksenii, Y. kristensenii and Y. intermedia was investigated. Among the strains involved in human pathology in Europe, Y. enterocolitica serovar O:3 was sensitive to 7 phages tested, while serovar O:9 was sensitive to all but one phage. Strains isolated from the environment, considered as non-pathogenic, were much less susceptible to the 7 phages. Based on these results, a new phage typing system which differentiates Y. enterocolitica O:3 and O:9 from the other Yersinia is proposed.

In vitro susceptibility of Yersinia kristensenii strains to beta-lactam antibiotics.

The beta-lactam antibiotic susceptibility and beta-lactamase activity of 22 Yersinia kristensenii strains were determined in order to compare these properties with those reported for Y. enterocolitica. Carbenicillin, cephaloridine, cefoxitin and cefotaxime were the most active antimicrobial agents tested against Y. kristensenii. All strains were resistant to penicillin G, cephalothin, cephapirin and cephalexin. On the other hand, ampicillin and cefazolin activity could be considerated as intermediate. The influence of incubation temperature was also evaluated. All Y. kristensenii strains were more resistant at 22 degrees C than at 37 degrees C to beta-lactam antibiotics. Susceptibility to cefazolin was not affected by the incubation temperature. All Y. kristensenii strains produce beta-lactamase. The substrate profile of this enzyme is that of a cephalosporinase: its activity was highest on cephalothin, cephapirin, cephaloridine and cefazolin, while hydrolysis of ampicillin and carbenicillin was not detected. beta-Lactamase-resistant cefoxitin and cefotaxime were not hydrolysed. A correlation between beta-lactam antibiotic susceptibility and the hydrolysis rate of these antibiotics by beta-lactamase was observed, except for cephaloridine and cefazolin; these antibiotics were very good beta-lactamase substrates, but their MIC values were low.

Utilization of cephalothin by Yersinia enterocolitica as sole carbon and energy source.

Two Yersinia enterocolitica strains were able to utilize the products of cephalothin degradation. The utilization of these products was shown by an increase of oxygen uptake by Y. enterocolitica with cephalothin as the only substrate, and by the growth of both strains with the hydrolysis products of cephalothin as sole energy and carbon sources. Nuclear magnetic resonance analysis of the cephalothin degradation reaction demonstrated the progressive disappearance of hydrolysis products. However, the products of benzylpenicillin degradation could not be utilized by Y. enterocolitica.

Isolation and characterization of moderately halophilic nonmotile rods from different saline habitats.

A total of 736 strains were isolated from samples taken from three different saline habitats: solar saltern, saline soils and the sea, near Alicante (Spain). For a further study 60 moderately halophilic nonmotile rods were selected and studied for 57 phenotypic characteristics. The highest proportion of moderately halophilic nonmotile rods were isolated from saline soils and in media with 10 or 20% salts, being very scarce in sea water samples. All were Gram-negative rods and were included in two groups: 33 oxidase positive strains could be assigned to the genus Flavobacterium and 24 oxidase negative strains to the genus Acinetobacter.