1,100 research outputs found
Physical conditions in CaFe interstellar clouds
Interstellar clouds that exhibit strong Ca I and Fe I lines were called CaFe
clouds. The ionisation equilibrium equations were used to model the column
densities of Ca II, Ca I, K I, Na I, Fe I and Ti II in CaFe clouds. The
chemical composition of CaFe clouds is that of the Solar System and no
depletion of elements onto dust grains is seen. The CaFe clouds have high
electron densities n=1 cm^-3 that leads to high column densities of neutral Ca
and Fe.Comment: Changed content, figure adde
Editorial: XXXIII SIMGBM Congress 2019 - Antimicrobials and Host-Pathogen Interactions
This Research Topic (RT) is intended to provide a collection of selected contributions in the broad area “Antimicrobials and Host-Pathogen Interactions” from the participants of “Microbiology 2019” congress organized by the Italian Society for General Microbiology and Microbial Biotechnology (SIMGBM, www.simgbm.it), which was held in Florence, Italy, on June 19–22, 2019. The congress was attended by 224 scientists from all over the world, and contributions relevant to this RT were collected from presentations in the following congress sessions: (i) Antibiotic resistome: where do antibiotic resistance genes come from? (ii) New antimicrobial strategies in the post-antibiotic era; (iii) Intercellular communication in host-pathogen interactions; (iv) New approaches to unravel fungal-host interactions; (v) Bacterial cell surface and signaling. The unifying concept of this RT originates from the increasing awareness that antimicrobial resistance (AMR) is a complex problem which should be addressed by a multifocal approach. Fundamental microbiological investigations in this direction involve understanding of the flow of AMR genes from the environment to human and animal pathogens, the development of new drugs to tackle AMR, and the discovery of new druggable targets to impairmicrobial growth and/or pathogenicity
Iodine biofortification in tomato
Iodine is an essential element in the human diet, and iodine deficiency is a significant health problem. No attempts to increase iodine content in plant-derived food (biofortification) have so far been particularly effective. We studied iodine uptake in tomato (Solanum lycopersicum L.) to evaluate whether it is possible to increase the iodine concentration in its fruits. Iodine translocation and storage inside tomato tissues were studied using radioactive iodine. Potassium iodide was also supplied at different concentrations to tomato plants to evaluate the resulting iodide concentration both in the vegetative tissues and the fruits. The results indicate that iodine was taken up better when supplied to the roots using hydroponically grown plants. However, a considerable amount of iodine was also stored after leaf treatment, suggesting that iodine transport through phloem also occurred. We found that tomato plants can tolerate high levels of iodine, stored both in the vegetative tissues and fruits at concentrations that are more than sufficient for the human diet. We conclude that tomato is an excellent crop for iodine-biofortification programs
RUOLO ED IMPORTANZA DI MOLECOLE SEGNALE NELLA FORMAZIONE DI BIOFILM BATTERICI, E LORO EFFETTO SU MECCANISMI DI PATOGENESI E DI RESISTENZA AGLI ANTIBIOTICI
Perfil de los extensionistas de la Dirección de Extensión Agraria del Ministerio de Agricultura y Ganadería del Paraguay
La extensión rural es una estrategia de gran importancia para favorecer procesos de desarrollo rural. No obstante, si bien existen numerosos trabajos científicos que abordan temáticas relacionadas con este tema, son pocos los que han estudiado de manera empírica la extensión rural. El presente trabajo tiene por objetivo describir y analizar el perfil de los extensionistas rurales que trabajan en la Dirección de Extensión Agraria (DEAg) del Ministerio de Agricultura y Ganadería del Paraguay. Para esto se realizó una encuesta a 169 de los 800 extensionistas que trabajan en la institución utilizándose una muestra incidental. El análisis fue realizado con el apoyo del software SPSS. Entre las conclusiones se destaca un aumento de la cantidad de extensionistas en los últimos años. No obstante, se observa que su situación es frágil, ya que un porcentaje muy elevado no posee contratos permanentes (55,4%) y no cuenta con formación universitaria (60,1%). Un dato desalentador es la inexistencia de relación estadística entre el nivel de formación y la posición jerárquica que ocupan los extensionistas en la institución (Kruskal Wallis: χ²=1,15(2), r =0,56). Respecto del género de los extensionistas, se destaca que la mayoría de ellos son hombres (71,6% vs. 28,4%). Más aun, las mujeres que ocupan cargos decisorios medios (como gerentes y jefes de agencia) son mucho menos que las esperadas si se toma en cuenta el porcentaje de empleados que constituyen en la DEAg (representan el 33,8% de los técnicos de campo y sólo el 6,9% de los cargos directivos en extensión)
Cellulose production is coupled to sensing of the pyrimidine biosynthetic pathway via c-di-GMP production by the DgcQ protein of Escherichia coli
Production of cellulose, a stress response-mediated process in enterobacteria, is modulated in Escherichia coli by the activity of the two pyrimidine nucleotide biosynthetic pathways, namely, the de novo biosynthetic pathway and the salvage pathway, which relies on the environmental availability of pyrimidine nitrogenous bases. We had previously reported that prevalence of the salvage over the de novo pathway triggers cellulose production via synthesis of the second messenger c-di-GMP by the DgcQ (YedQ) diguanylate cyclase. In this work, we show that DgcQ enzymatic activity is enhanced by UTP, whilst being inhibited by N-carbamoyl-aspartate, an intermediate of the de novo pathway. Thus, direct allosteric control by these ligands allows full DgcQ activity exclusively in cells actively synthesizing pyrimidine nucleotides via the salvage pathway. Inhibition of DgcQ activity by N-carbamoyl-aspartate appears to be favoured by protein-protein interaction between DgcQ and PyrB, a subunit of aspartate transcarbamylase, which synthesizes N-carbamoyl-aspartate. Our results suggest that availability of pyrimidine bases might be sensed, somehow paradoxically, as an environmental stress by E. coli. We hypothesize that this link might have evolved since stress events, leading to extensive DNA/RNA degradation or lysis of neighbouring cells, can result in increased pyrimidine concentrations and activation of the salvage pathway
Analysis and characterization of mouse monoclonal antibodies reactive to Chikungunya virus (CHIKV)
occurring in 1984). However, plague has made an astonishing comeback in the last decade. Methods: n/a. Results: After a silence of 50 years, an outbreak of bubonic plague suddenly occurred close to Oran in Algeria, in June 2003. Eighteen bubonic cases were identified, and Yersinia pestis was isolated from 6 patients. In July 2008, a new cluster was reported among nomads 300 km south of the first one. Four members of one family were affected and one died. The bacillus was isolated from one patient. No epidemiological association was identified between the two events. On June 2009, 25 years after the last occurrence in the country, Libya reported five confirmed cases of bubonic plague in the Tobruk area. Y. pestis was isolated from three patients. In all these cases, further local ecological investigations confirmed the existence of a natural focus The re-emergence of human plague in the region is not without international consequences. Two of the last concerned natural foci are close to an international port which raises the question of the potential exportation of infected rodents. Cross-border tensions, between ''plague countries'' and ''plague-free countries'' have been observed although the foci's limits are unknown as any systematic ecological investigation and surveillance is lacking. Additionally, the potential weaponization of Y.pestis together with international political tensions feed a recurrent interest in plague in North Africa. False rumors of alleged military laboratory accidents or terrorist acts are routinely mentioned, although events could be first explained by the natural history of the disease. Conclusion: In this context, and although the number of human cases has been very limited so far, the first priorities are to establish appropriate ecological surveillance and agree on a common plague control strategy for the region
A deep X-ray observation of M82 with XMM-Newton
We report on the analysis of a deep (100 ks) observation of the starburst
galaxy M82 with the EPIC and RGS instruments on board the X-ray telescope
XMM-Newton. The broad-band (0.5-10 keV) emission is due to at least three
spectral components: i) continuum emission from point sources; ii) thermal
plasma emission from hot gas; iii) charge exchange emission from neutral metals
(Mg and Si). The plasma emission has a double-peaked differential emission
measure, with the peaks at ~0.5 keV and ~7 keV. Spatially resolved spectroscopy
has shown that the chemical absolute abundances are not uniformly distributed
in the outflow, but are larger in the outskirts and smaller close to the galaxy
centre. The abundance ratios also show spatial variations. The X-ray derived
Oxygen abundance is lower than that measured in the atmospheres of red
supergiant stars, leading to the hypothesis that a significant fraction of
Oxygen ions have already cooled off and no longer emit at energies > ~0.5 keV.Comment: Accepted for publication in MNRAS. 20 pages, 15 figures, LaTeX2
EUV emission lines and diagnostics observed with Hinode/EIS
Quiet Sun and active region spectra from the Hinode/EIS instrument are
presented, and the strongest lines from different temperature regions
discussed. A list of emission lines recommended to be included in EIS
observation studies is presented based on analysis of blending and diagnostic
potential using the CHIANTI atomic database. In addition we identify the most
useful density diagnostics from the ions covered by EIS.Comment: 14 pages, 3 figures, submitted to PASJ Hinode first results issu
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