Nanomolar Levels of Dimethylsulfoniopropionate, Dimethylsulfonioacetate, and Glycine Betaine Are Sufficient To Confer Osmoprotection to <i>Escherichia coli</i>

ABSTRACT We combined the use of low inoculation titers (300 ± 100 CFU/ml) and enumeration of culturable cells to measure the osmoprotective potentialities of dimethylsulfoniopropionate (DMSP), dimethylsulfonioacetate (DMSA), and glycine betaine (GB) for salt-stressed cultures of Escherichia coli . Dilute bacterial cultures were grown with osmoprotectant concentrations that encompassed the nanomolar levels of GB and DMSP found in nature and the millimolar levels of osmoprotectants used in standard laboratory osmoprotection bioassays. Nanomolar concentrations of DMSA, DMSP, and GB were sufficient to enhance the salinity tolerance of E. coli cells expressing only the ProU high-affinity general osmoporter. In contrast, nanomolar levels of osmoprotectants were ineffective with a mutant strain (GM50) that expressed only the low-affinity ProP osmoporter. Transport studies showed that DMSA and DMSP, like GB, were taken up via both ProU and ProP. Moreover, ProU displayed higher affinities for the three osmoprotectants than ProP displayed, and ProP, like ProU, displayed much higher affinities for GB and DMSA than for DMSP. Interestingly, ProP did not operate at substrate concentrations of 200 nM or less, whereas ProU operated at concentrations ranging from 1 nM to millimolar levels. Consequently, proU + strains of E. coli , but not the proP + strain GM50, could also scavenge nanomolar levels of GB, DMSA, and DMSP from oligotrophic seawater. The physiological and ecological implications of these observations are discussed. </jats:p

Predictive genomic and transcriptomic analysis on endoscopic ultrasound-guided fine needle aspiration materials from primary pancreatic adenocarcinoma: a prospective multicentre study

International audienc

Comparison of the measured atmospheric muon rate with Monte Carlo simulations and sensitivity study for detection of prompt atmospheric muons with KM3NeT

The KM3NeT Collaboration has successfully deployed the first detection units of the next genera- tion undersea neutrino telescopes in the Mediterranean Sea at the two sites in Italy and in France. The data sample collected between December 2016 and January 2020 has been used to measure the atmospheric muon rate at two different depths under the sea level: 3.5 km with KM3NeT- ARCA and 2.5 km with KM3NeT-ORCA. Atmospheric muons represent an abundant signal in a neutrino telescope and can be used to test the reliability of the Monte Carlo simulation chain and to study the physics of extensive air showers caused by highly-energetic primary nuclei impinging the Earth’s atmosphere. At energies above PeV the contribution from prompt muons, created right after the first interaction in the shower, is expected to become dominant, however its existence has not yet been experimentally confirmed. In this talk, data collected with the first detection units of KM3NeT are compared to Monte Carlo simulations based on MUPAGE and CORSIKA codes. The main features of the simulation and reconstruction chains are presented. Additionally, the first results of the simulated signal from the prompt muon component for KM3NeT-ARCA and KM3NeT-ORCA obtained with CORSIKA are discussed

KM3NeT/ARCA sensitivity to transient neutrino sources

The KM3NeT Collaboration is constructing a km3-volume neutrino telescope in the Mediterranean sea, ARCA (Astroparticle Research with Cosmics in the Abyss), for the detection and subsequent study of high-energy cosmic neutrinos.This telescope will be able to reconstruct the arrival direction of the neutrinos with a precision of ~0.1 degrees. The configuration of ARCA makes it sensitive to neutrinos in a wide energy range, from sub-TeV up to tens of PeV. Moreover, this detector has a large field of view and a very high duty cycle, allowing a full-sky (and all-flavours) searches. All these features make ARCA an excellent candidate to study transient neutrino sources. Atmospheric muons and neutrinos, produced by primary cosmic rays, constitute the main background for ARCA. This background can be several orders of magnitude higher than the expected cosmic neutrino flux. In this work, we introduce an event selection which reduces the background up to a negligible level inside the region of interest and within the search time window. The ARCA performance to detect a transient neutrino flux, including the effective area, sensitivity and discovery potential, are provided for a given test source, and for different time windows

Comparison of the measured atmospheric muon rate with Monte Carlo simulations and sensitivity study for detection of prompt atmospheric muons with KM3NeT

The KM3NeT Collaboration has successfully deployed the first detection units of the next genera- tion undersea neutrino telescopes in the Mediterranean Sea at the two sites in Italy and in France. The data sample collected between December 2016 and January 2020 has been used to measure the atmospheric muon rate at two different depths under the sea level: 3.5 km with KM3NeT- ARCA and 2.5 km with KM3NeT-ORCA. Atmospheric muons represent an abundant signal in a neutrino telescope and can be used to test the reliability of the Monte Carlo simulation chain and to study the physics of extensive air showers caused by highly-energetic primary nuclei impinging the Earth’s atmosphere. At energies above PeV the contribution from prompt muons, created right after the first interaction in the shower, is expected to become dominant, however its existence has not yet been experimentally confirmed. In this talk, data collected with the first detection units of KM3NeT are compared to Monte Carlo simulations based on MUPAGE and CORSIKA codes. The main features of the simulation and reconstruction chains are presented. Additionally, the first results of the simulated signal from the prompt muon component for KM3NeT-ARCA and KM3NeT-ORCA obtained with CORSIKA are discussed

KM3NeT/ARCA sensitivity to transient neutrino sources

The KM3NeT Collaboration is constructing a km3-volume neutrino telescope in the Mediterranean sea, ARCA (Astroparticle Research with Cosmics in the Abyss), for the detection and subsequent study of high-energy cosmic neutrinos.This telescope will be able to reconstruct the arrival direction of the neutrinos with a precision of ~0.1 degrees. The configuration of ARCA makes it sensitive to neutrinos in a wide energy range, from sub-TeV up to tens of PeV. Moreover, this detector has a large field of view and a very high duty cycle, allowing a full-sky (and all-flavours) searches. All these features make ARCA an excellent candidate to study transient neutrino sources. Atmospheric muons and neutrinos, produced by primary cosmic rays, constitute the main background for ARCA. This background can be several orders of magnitude higher than the expected cosmic neutrino flux. In this work, we introduce an event selection which reduces the background up to a negligible level inside the region of interest and within the search time window. The ARCA performance to detect a transient neutrino flux, including the effective area, sensitivity and discovery potential, are provided for a given test source, and for different time windows

KM3NeT Detection Unit Line Fit reconstruction using positioning sensors data

The KM3NeT collaboration is constructing two large neutrino detectors in the Mediterranean Sea: KM3NeT/ARCA, located near Sicily and aiming at neutrino astronomy, and KM3NeT/ORCA, located near Toulon and designed for neutrino oscillation studies. The two detectors, together, will have hundreds of Detection Units (DUs) with 18 Digital Optical Modules (DOMs) maintained vertical by buoyancy, forming a large 3D optical array for detecting the Cherenkov light produced by particle produced in neutrino interactions. To properly reconstruct the direction of the incoming neutrino, the position of the DOMs must be known precisely with an accuracy of less than 10 cm, and since the DUs are affected by sea current the position will be measured every 10 minutes. For this purpose, there are acoustic and orientation sensors inside the DOMs. An Attitude Heading Reference System (AHRS) chip provides the components values of the Acceleration and Magnetic field in the DOM, from which it is possible to calculate Yaw, Pitch, and Roll for each floor of the line. A piezo sensor detects the signals from fixed acoustic emitters on the sea floor, so to position it by trilateration. Data from these sensors are used as an input to reconstruct the shape of the entire line based on a DU Line Fit mechanical model. This poster presents an overview of the KM3NeT monitoring system, as well as the line fit model and its results

Indirect dark matter searches with neutrinos from the Galactic Centre region with the ANTARES and KM3NeT telescopes

An anomalous flux of neutrinos produced in hypothetical annihilations or decays of dark matter inside a source would produce a signal observable with neutrino telescopes. As suggested by observations, a conspicuous amount of dark matter is believed to accumulate in the centre of our Galaxy, which is in neat visibility for the Mediterranean underwater telescopes ANTARES and KM3NeT. Searches have been conducted with a maximum likelihood method to identify the presence of a dark matter signature in the neutrino flux measured by ANTARES. Results of all-flavour searches for WIMPs with masses from 50 GeV/c2 up to 100 TeV/c2 over the whole operation period from 2007 to 2020 are presented here. Alternative scenarios which propose a dark matter candidate in the heavy sector extensions of the Standard Model would produce a clear signature in the ANTARES telescope, that can exploit its view of the Galactic Centre up to high energies. The presentation of Galactic Centre searches is completed with ongoing analyses and future potential of the KM3NeT telescope, in phased construction in the Mediterranean Sea