Complete Genome Sequences of Three Clinical Listeria monocytogenes Sequence Type 8 Strains from Recent German Listeriosis Outbreaks

We report here the closed genome sequences of three clinical Listeria monocytogenes strains of multilocus sequence typing (MLST) sequence type 8 (ST8). These strains are representatives of three separate listeriosis outbreak clusters (Alpha1, Pi4, and Sigma1) that affected Germany between 2012 and 2020.Peer Reviewe

Trapped field potential of commercial Y-Ba-Cu-O bulk superconductors designed for applications

Bulk high-temperature superconductors (HTSs) that act as a trap field magnet establish a novel type of magnetic field source, which is significantly different from that of a permanent magnet or solenoid; therefore, they can be potentially used in magnetic-force-based applications. However, the primary issues related to the commercial use of the bulk HTS technology are established on the enhancement of trapped magnetic fields, as well as their reliability and reproducibility at temperatures achievable with off-the-shelf cryocoolers. This study presents experimental investigations on the strong trapped magnetic fields observed in commercial Y-Ba-Cu-O bulk HTSs produced as a double-sample stack, a cylindrical bulk, and a ring-shaped bulk. Consequently, a reliable and reproducible magnetic field of 9.5 T at 50 K was trapped in commercial Y-Ba-Cu-O assembled as a double-sample stack. In this case, shrink-fit encapsulation with either aluminum or stainless steel tube ensured equally effective reinforcement. Higher magnetization, although accompanied with partial flux jumps, yielded a trapped field of 16.85 T at 30 K, which is comparable to the reported record trapped fields. Finally, a maximum trapped field of 9.78 T - the strongest trapped field reported to date - was attained in the 6 mm hollow space of the ring-shaped bulk HTS

The PadR-like transcriptional regulator LftR ensures efficient invasion of Listeria monocytogenes into human host cells

Invasion of the bacterial pathogen Listeria monocytogenes into human host cells requires specialized surface molecules for attachment and induction of phagocytosis. However, efficient invasion is also dependent on factors with house-keeping functions, such as SecA2-dependent secretion of autolysins for post-divisional segregation of daughter cells. Mutations in this pathway prevent degradation of peptidoglycan cross-walls, so that long cell chains are formed that cannot be phagocytosed. The extreme chaining of such mutants manifests as rough colony phenotype. One rough clone was isolated from a transposon library with a transposon insertion in the uncharacterized lmo0720 gene (lftS) together with a spontaneous point mutation in the secA2 gene. We separated both mutations and demonstrated that this point mutation in the intramolecular regulator 2 domain of SecA2 was sufficient to inactivate the protein. In contrast, lftS deletion did not cause a ΔsecA2-like phenotype. lftS is located in an operon with lftR (lmo0719), encoding a PadR-like transcriptional regulator, and lftR deletion affected growth, invasion and day-light dependent coordination of swarming. Inactivation of lftS partially suppressed these phenotypes, suggesting a functional relationship between LftR and LftS. However, the invasion defect of the ΔlftR mutant was only marginally suppressed by lftS removal. LftR regulates expression of the lmo0979–0980 (lieAB) operon, encoding a putative multidrug resistance transporter and lieAB transcription was strongly upregulated in the absence of LftR. Deletion of lieAB in the ΔlftR background restores wild type-like invasion levels. Hence, we conclude that tight transcriptional repression of the lieAB operon is essential for efficient listerial host cell invasion

Eclipsing Binaries with Possible Light-Time Effect

The period changes of six eclipsing binaries have been studied with focus on the light-time effect. With the least squares method we also calculated parameters of such an effect and properties of the unresolved body in these systems. With these results we discussed the probability of presence of such bodies in the systems with respect to possible confirmation by another method. In two systems we also suggested the hypothesis of fourth body or magnetic activity for explanation of the "second-order variability" after subtraction of the light-time effect of the third body.Comment: 4 pages, 1 figure, 2 tables, conference proceeding

Electromagnetic stirring of glass melts using Lorentz forces - Experimental results

The question as to whether it is possible to stir glass melts using electromagnetic (Lorentz) forces has been controversially discussed in the past. Α series of accurate experiments is reported in which the buoyancy driven motion of a directly electrically heated glass melt in a cylindrical crucible has been modified by applying an external alternating magnetic field. Using temperature measurements directly in the melt it is demonstrated for the first time that the Lorentz force created in the melt leads to a homogenization of the temperature and density distributions because of an enhancement of the flow. Moreover, evidence is provided for an improvement of the glass homogeneity. The feasibility analysis provides rational possibilities for the application of magnetic fields for electromagnetic flow control in glassmaking processes