163 research outputs found
Multiple cotransformations in Coprinus cinereus
Plasmids usually integrate ectopically into the genome of the homobasidiomycete Coprinus cinereus in transformations. Often, integration occurs at multiple sites indicating that more than one plasmid copy was incorporated. This feature prompted us to study transformation with mixtures of several different plasmids in several genetic backgrounds. We found multiple cotransformation to be efficient even with four different plasmids. Simultaneous uptake of a second plasmid was between 5-55%, of two additional plasmids between 3-18% and 3% for three additional plasmids. These high frequencies make possible the analysis of interactions between different heterologous genes introduced into the same nucleus
Magnetism, spin texture and in-gap states: Atomic specialization at the surface of oxygen-deficient SrTiO
Motivated by recent spin- and angular-resolved photoemission (SARPES)
measurements performed on the two-dimensional electronic states confined near
the (001) surface of SrTiO in the presence of oxygen vacancies, we explore
their spin structure by means of ab initio density functional theory (DFT)
calculations of slabs. Relativistic nonmagnetic DFT calculations display
Rashba-like spin winding with a splitting of a few meV and when surface
magnetism on the Ti ions is in- cluded, bands become spin-split with an energy
difference ~100 meV at the point, consistent with SARPES findings.
While magnetism tends to suppress the effects of the relativistic Rashba
interaction, signatures of it are still clearly visible in terms of complex
spin textures. Furthermore, we observe an atomic specialization phenomenon,
namely, two types of electronic contributions: one is from Ti atoms neighboring
the oxygen vacancies that acquire rather large magnetic moments and mostly
create in-gap states; another comes from the partly polarized t
itinerant electrons of Ti atoms lying further away from the oxygen vacancy,
which form the two-dimensional electron system and are responsible for the
Rashba spin winding and the spin splitting at the Fermi surface.Comment: 6 pages, 4 figures, for Suppl. Mat. please contact first autho
Architecture of soil microaggregates: Advanced methodologies to explore properties and functions
The functions of soils are intimately linked to their three-dimensional pore space and the associated biogeochemical interfaces, mirrored in the complex structure that developed during pedogenesis. Under stress overload, soil disintegrates into smaller compound structures, conventionally named aggregates. Microaggregates (<250 µm) are recognized as the most stable soil structural units. They are built of mineral, organic, and biotic materials, provide habitats for a vast diversity of microorganisms, and are closely involved in the cycling of matter and energy. However, exploring the architecture of soil microaggregates and their linkage to soil functions remains a challenging but demanding scientific endeavor. With the advent of complementary spectromicroscopic and tomographic techniques, we can now assess and visualize the size, composition, and porosity of microaggregates and the spatial arrangement of their interior building units. Their combinations with advanced experimental pedology, multi-isotope labeling experiments, and computational approaches pave the way to investigate microaggregate turnover and stability, explore their role in element cycling, and unravel the intricate linkage between structure and function. However, spectromicroscopic techniques operate at different scales and resolutions, and have specific requirements for sample preparation and microaggregate isolation; hence, special attention must be paid to both the separation of microaggregates in a reproducible manner and the synopsis of the geography of information that originates from the diverse complementary instrumental techniques. The latter calls for further development of strategies for synlocation and synscaling beyond the present state of correlative analysis. Here, we present examples of recent scientific progress and review both options and challenges of the joint application of cutting-edge techniques to achieve a sophisticated picture of the properties and functions of soil microaggregates
Two-dimensional wave patterns of spreading depolarization: retracting, re-entrant, and stationary waves
We present spatio-temporal characteristics of spreading depolarizations (SD)
in two experimental systems: retracting SD wave segments observed with
intrinsic optical signals in chicken retina, and spontaneously occurring
re-entrant SD waves that repeatedly spread across gyrencephalic feline cortex
observed by laser speckle flowmetry. A mathematical framework of
reaction-diffusion systems with augmented transmission capabilities is
developed to explain the emergence and transitions between these patterns. Our
prediction is that the observed patterns are reaction-diffusion patterns
controlled and modulated by weak nonlocal coupling. The described
spatio-temporal characteristics of SD are of important clinical relevance under
conditions of migraine and stroke. In stroke, the emergence of re-entrant SD
waves is believed to worsen outcome. In migraine, retracting SD wave segments
cause neurological symptoms and transitions to stationary SD wave patterns may
cause persistent symptoms without evidence from noninvasive imaging of
infarction
Significant increase in azithromycin “resistance” and susceptibility to ceftriaxone and cefixime in Neisseria gonorrhoeae isolates in 26 European countries, 2019
Euro-GASP network: Claudia Eder, Sonja Pleininger, Steliana Huhlescu, Irith de Baetselier, Blaženka Hunjak, Tatjana Nemeth Blažić, Panagiota Maikanti-Charalampous, Despo Pieridou, Hana Zákoucká, Helena Žemličková, Steen Hoffmann, Susan Cowan, Rita Peetso, Jelena Viktorova, Ndeindo Ndeikoundam, Beatrice Bercot, Anu Patari Sampo, Vesa Kirjavainen, Susanne Buder, Klaus Jansen, Vivi Miriagou, Eszter Balla, Mária Dudás, Guðrún Sigmundsdóttir, Lena Ros Asmundsdottir, Sinead Saab, Brendan Crowley, Anna Carannante, Paola Stefanelli, Gatis Pakarna, Violeta Mavcutko, Robert Cassar, Christopher Barbara, Francesca Vella, Alje Van Dam, Ineke Linde, Dominique Caugant, Hilde Kløvstad, Beata Mlynarczyk-Bonikowska, Maria-José Borrego, Peter Pavlik, Irena Klavs, Tanja Kustec, Julio Vazquez, Asuncion Diaz, Raquel Abad Torreblanca, Inga Velicko, Magnus Unemo, Helen Fifer, Kate TempletonBackground: The European Gonococcal Antimicrobial Surveillance Programme (Euro-GASP) performs annual sentinel surveillance of Neisseria gonorrhoeae susceptibility to therapeutically relevant antimicrobials across the European Union/European Economic Area (EU/EEA). We present the Euro-GASP results from 2019 (26 countries), linked to patient epidemiological data, and compared with data from previous years.
Methods: Agar dilution and minimum inhibitory concentration (MIC) gradient strip methodologies were used to determine the antimicrobial susceptibility (using EUCAST clinical breakpoints, where available) of 3239 N. gonorrhoeae isolates from 26 countries across the EU/EEA. Significance of differences compared with Euro-GASP results in previous years was analysed using Z-test and the Pearson's χ2 test was used to assess significance of odds ratios for associations between patient epidemiological data and antimicrobial resistance.
Results: European N. gonorrhoeae isolates collected between 2016 and 2019 displayed shifting MIC distributions for; ceftriaxone, with highly susceptible isolates increasing over time and occasional resistant isolates each year; cefixime, with highly-susceptible isolates becoming increasingly common; azithromycin, with a shift away from lower MICs towards higher MICs above the EUCAST epidemiological cut-off (ECOFF); and ciprofloxacin which is displaying a similar shift in MICs as observed for azithromycin. In 2019, two isolates displayed ceftriaxone resistance, but both isolates had MICs below the azithromycin ECOFF. Cefixime resistance (0.8%) was associated with patient sex, with resistance higher in females compared with male heterosexuals and men-who-have-sex-with-men (MSM). The number of countries reporting isolates with azithromycin MICs above the ECOFF increased from 76.9% (20/26) in 2016 to 92.3% (24/26) in 2019. Isolates with azithromycin MICs above the ECOFF (9.0%) were associated with pharyngeal infection sites. Following multivariable analysis, ciprofloxacin resistance remained associated with isolates from MSM and heterosexual males compared with females, the absence of a concurrent chlamydial infection, pharyngeal infection sites and patients ≥ 25 years of age.
Conclusions: Resistance to ceftriaxone and cefixime remained uncommon in EU/EEA countries in 2019 with a significant decrease in cefixime resistance observed between 2016 and 2019. The significant increase in azithromycin "resistance" (azithromycin MICs above the ECOFF) threatens the effectiveness of the dual therapy (ceftriaxone + azithromycin), i.e., for ceftriaxone-resistant cases, currently recommended in many countries internationally and requires close monitoring.The study was funded by the European Centre for Disease Prevention and Control (Framework Contract No. ECDC/2017/004).info:eu-repo/semantics/publishedVersio
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