401 research outputs found
Riboswitch RSthiT as a molecular tool in Lactococcus lactis
Previous RNA sequencing has allowed the identification of 129 long 5′ untranslated regions (UTRs) in the Lactococcus lactis MG1363 transcriptome. These sequences potentially harbor cis-acting riboswitches. One of the identified extended 5′ UTRs is a putative thiamine pyrophosphate (TPP) riboswitch. It is located immediately upstream of the thiamine transporter gene thiT (llmg_0334). To confirm this assumption, the 5′-UTR sequence was placed upstream of the gene encoding the superfolder green fluorescent protein (sfGFP), sfgfp, allowing the examination of the expression of sfGFP in the presence or absence of thiamine in the medium. The results show that this sequence indeed represents a thiamine-responsive TPP riboswitch. This RNA-based genetic control device was used to successfully restore the mutant phenotype of an L. lactis strain lacking the major autolysin gene, acmA. The L. lactis thiT TPP riboswitch (RS(thiT)) is a useful molecular genetic tool enabling the gradual downregulation of the expression of genes under its control by adjusting the thiamine concentration. IMPORTANCE The capacity of microbes with biotechnological importance to adapt to and survive under quickly changing industrial conditions depends on their ability to adequately control gene expression. Riboswitches are important RNA-based elements involved in rapid and precise gene regulation. Here, we present the identification of a natural thiamine-responsive riboswitch of Lactococcus lactis, a bacterium used worldwide in the production of dairy products. We used it to restore a genetic defect in an L. lactis mutant and show that it is a valuable addition to the ever-expanding L. lactis genetic toolbox
Scattering of magnetosonic waves in a relativistic and an-isotropic magnetised plasma
Gravitational waves (GW) propagating through a magnetised plasma excite
low-frequency magnetohydrodynamic (MHD) waves. In this paper we investigate
whether these waves can produce observable radio emission at higher frequencies
by scattering on an an-isotropic intrinsically relativistic distribution of
electrons and positrons in the force-free wind surrounding a double neutron
star binary merger. The relativistic particle distribution is assumed to be
strictly along the magnetic field lines, while the magneto-plasma streams out
at a relativistic speed from the neutron stars. In the case of Compton
scattering of an incident MHD wave transverse to the magnetic field, we find
that the probability of scattering to both a transverse x-mode and a
quasi-transverse Langmuir-o mode is suppressed when the scattered frequency is
below the local relativistic gyro-frequency, i.e. when the magnetic field is
very strong.Comment: 13 pages, 6 figures (2 color). Accepted for publication in Monthly
Notices of the Royal Astronomical Society, MNRAS, to appear on-line mid Marc
NEMO: Real-Time Noise and Exhaust Emissions Monitoring for Sustainable and Intelligent Transportation Systems
Research and development efforts on sustainable and intelligent transportation systems are accelerating globally as the transportation sector contributes significantly to environmental pollution and produces a variety of noise and emissions that impact the climate. With the emergence of ubiquitous sensors and Internet of Things (IoT) applications, finding innovative transport solutions, including adequate climate change mitigation, will all be vital components of a sustainable transport future. Thus, it is essential to continuously monitor noise and exhaust emissions from road vehicles, trains, and ships. As a contribution to addressing this as part of an effort of the European Union project called “NEMO: Noise and Emissions Monitoring and Radical Mitigation", in this paper, we propose the design and development of a real-time noise and exhaust emissions monitoring for sustainable and intelligent transportation systems. We report real-world field testing in some European cities where vehicle noise and exhaust emissions data are gathered in the cloud-enabled Nautilus platform and evaluated using artificial intelligence (AI) algorithms to determine their categorization into different classes of emitters and thereby enabling the infrastructure managers to define logic and actions to be taken by high emitters in near real-time. We outline the creation of a complete NEMO solution to monitor and reduce noise and emissions in real time for sustainable and intelligent transportation systems.acceptedVersio
A very brief description of LOFAR - the Low Frequency Array
LOFAR (Low Frequency Array) is an innovative radio telescope optimized for
the frequency range 30-240 MHz. The telescope is realized as a phased aperture
array without any moving parts. Digital beam forming allows the telescope to
point to any part of the sky within a second. Transient buffering makes
retrospective imaging of explosive short-term events possible. The scientific
focus of LOFAR will initially be on four key science projects (KSPs): 1)
detection of the formation of the very first stars and galaxies in the universe
during the so-called epoch of reionization by measuring the power spectrum of
the neutral hydrogen 21-cm line (Shaver et al. 1999) on the ~5' scale; 2)
low-frequency surveys of the sky with of order expected new sources; 3)
all-sky monitoring and detection of transient radio sources such as gamma-ray
bursts, x-ray binaries, and exo-planets (Farrell et al. 2004); and 4) radio
detection of ultra-high energy cosmic rays and neutrinos (Falcke & Gorham 2003)
allowing for the first time access to particles beyond 10^21 eV (Scholten et
al. 2006). Apart from the KSPs open access for smaller projects is also
planned. Here we give a brief description of the telescope.Comment: 2 pages, IAU GA 2006, Highlights of Astronomy, Volume 14, K.A. van
der Hucht, e
- …