Dynamics and quantitative contribution of the aminoglycoside 6'--acetyltransferase type Ib to amikacin resistance.

Aminoglycosides are essential components in the available armamentarium to treat bacterial infections. The surge and rapid dissemination of resistance genes strongly reduce their efficiency, compromising public health. Among the multitude of modifying enzymes that confer resistance to aminoglycosides, the aminoglycoside 6'--acetyltransferase type Ib [AAC(6')-Ib] is the most prevalent and relevant in the clinical setting as it can inactivate numerous aminoglycosides, such as amikacin.

Dynamics and quantitative contribution of the aminoglycoside 6'--acetyltransferase type Ib [AAC(6')-Ib] to amikacin resistance.

Aminoglycosides are essential components in the available armamentarium to treat bacterial infections. The surge and rapid dissemination of resistance genes strongly reduce their efficiency, compromising public health. Among the multitude of modifying enzymes that confer resistance to aminoglycosides, the aminoglycoside acetyltransferase AAC(6')-Ib is the most prevalent and relevant in the clinical setting as it can inactivate numerous aminoglycosides, such as amikacin.

Magnetic Breakdown and Topology in the Kagome Superconductor CsV_{3}Sb_{5} under High Magnetic Field.

The recently discovered layered kagome metals of composition AV_{3}Sb_{5} (A=K, Rb, Cs) exhibit a complex interplay among superconductivity, charge density wave order, topologically nontrivial electronic band structure and geometrical frustration. Here, we probe the electronic band structure underlying these exotic correlated electronic states in CsV_{3}Sb_{5} with quantum oscillation measurements in pulsed fields up to 86 T. The high-field data reveal a sequence of magnetic breakdown orbits that allows the construction of a model for the folded Fermi surface of CsV_{3}Sb_{5}.

Escherichia coli K-12 has two distinguishable PriA-PriB replication restart pathways.

In Escherichia coli, PriA, PriB, PriC, and DnaT proteins mediate three pathways for Replication Restart called PriA-PriB, PriA-PriC, and PriC. PriA is crucial for two of the three pathways. Its absence leads to slow growth, high basal levels of SOS expression, poorly partitioning nucleoids, UV sensitivity, and recombination deficiency.

Dynamics of Proteins and Macromolecular Machines in Escherichia coli.

Proteins are major contributors to the composition and the functions in the cell. They often assemble into larger structures, macromolecular machines, to carry out intricate essential functions. Although huge progress in understanding how macromolecular machines function has been made by reconstituting them , the role of the intracellular environment is still emerging.

Disorder raises the critical temperature of a cuprate superconductor.

With the discovery of charge-density waves (CDWs) in most members of the cuprate high-temperature superconductors, the interplay between superconductivity and CDWs has become a key point in the debate on the origin of high-temperature superconductivity. Some experiments in cuprates point toward a CDW state competing with superconductivity, but others raise the possibility of a CDW-superconductivity intertwined order or more elusive pair-density waves (PDWs). Here, we have used proton irradiation to induce disorder in crystals of [Formula: see text] and observed a striking 50% increase of [Formula: see text], accompanied by a suppression of the CDWs.

Function of a strand-separation pin element in the PriA DNA replication restart helicase.

DNA helicases are motor proteins that couple the chemical energy of nucleoside triphosphate hydrolysis to the mechanical functions required for DNA unwinding. Studies of several helicases have identified strand-separating "pin" structures that are positioned to intercept incoming dsDNA and promote strand separation during helicase translocation. However, pin structures vary among helicases and it remains unclear whether they confer a conserved unwinding mechanism.

Skyrmion Lattice Topological Hall Effect near Room Temperature.

Magnetic skyrmions are stable nanosized spin structures that can be displaced at low electrical current densities. Because of these properties, they have been proposed as building blocks of future electronic devices with unprecedentedly high information density and low energy consumption. The electrical detection of an ordered skyrmion lattice via the Topological Hall Effect (THE) in a bulk crystal, has so far been demonstrated only at cryogenic temperatures in the MnSi family of compounds.

Structure-specific DNA replication-fork recognition directs helicase and replication restart activities of the PriA helicase.

DNA replication restart, the essential process that reinitiates prematurely terminated genome replication reactions, relies on exquisitely specific recognition of abandoned DNA replication-fork structures. The PriA DNA helicase mediates this process in bacteria through mechanisms that remain poorly defined. We report the crystal structure of a PriA/replication-fork complex, which resolves leading-strand duplex DNA bound to the protein.

A Mutant Expressed in Two Pieces Has Almost Full Activity in Escherichia coli K-12.

The ability to restart broken DNA replication forks is essential across all domains of life. In , the , , , and genes encode the replication restart proteins (RRPs) to accomplish this task. PriA plays a critical role in replication restart such that its absence reveals a dramatic phenotype: poor growth, high basal levels of SOS expression, poorly partitioned nucleoids (Par), UV sensitivity, and recombination deficiency (Rec).

Porous Coordination Polymer Based on Bipyridinium Carboxylate Linkers with High and Reversible Ammonia Uptake.

The zwitterionic bipyridinium carboxylate ligand 1,1'-bis(4-carboxyphenyl)-4,4'-bipyridinium (pc1) in the presence of cadmium chloride affords novel porous coordination polymers (PCPs): [Cd4(pc1)3Cl6]·CdCl4·guest (1) crystallizing in the P3̅1c space group. In the structure, [Cd4Cl6(CO2)6] building units are linked together by six pc1 ligands, leading to a 3D high-symmetrical network exhibiting hexagonal channels along the c axis. The walls of this PCP consist of cationic electron-acceptor bipyridinium units.

Structure and Function of the PriC DNA Replication Restart Protein.

Collisions between DNA replication complexes (replisomes) and barriers such as damaged DNA or tightly bound protein complexes can dissociate replisomes from chromosomes prematurely. Replisomes must be reloaded under these circumstances to avoid incomplete replication and cell death. Bacteria have evolved multiple pathways that initiate DNA replication restart by recognizing and remodeling abandoned replication forks and reloading the replicative helicase.

Toward Superconducting Critical Current by Design.

A new critical-current-by-design paradigm is presented. It aims at predicting the optimal defect landscape in superconductors for targeted applications by elucidating the vortex dynamics responsible for the bulk critical current. To this end, critical current measurements on commercial high-temperature superconductors are combined with large-scale time-dependent Ginzburg-Landau simulations of vortex dynamics.

Statistical distance as a measure of physiological dysregulation is largely robust to variation in its biomarker composition.

Physiological dysregulation may underlie aging and many chronic diseases, but is challenging to quantify because of the complexity of the underlying systems. Recently, we described a measure of physiological dysregulation, DM, that uses statistical distance to assess the degree to which an individual's biomarker profile is normal versus aberrant. However, the sensitivity of DM to details of the calculation method has not yet been systematically assessed.

Detection of a novel, integrative aging process suggests complex physiological integration.

Many studies of aging examine biomarkers one at a time, but complex systems theory and network theory suggest that interpretations of individual markers may be context-dependent. Here, we attempted to detect underlying processes governing the levels of many biomarkers simultaneously by applying principal components analysis to 43 common clinical biomarkers measured longitudinally in 3694 humans from three longitudinal cohort studies on two continents (Women's Health and Aging I & II, InCHIANTI, and the Baltimore Longitudinal Study on Aging). The first axis was associated with anemia, inflammation, and low levels of calcium and albumin.

Two-dimensional mineral [Pb2BiS3][AuTe2]: high-mobility charge carriers in single-atom-thick layers.

Two-dimensional (2D) electronic systems are of wide interest due to their richness in chemical and physical phenomena and potential for technological applications. Here we report that [Pb2BiS3][AuTe2], known as the naturally occurring mineral buckhornite, hosts 2D carriers in single-atom-thick layers. The structure is composed of stacking layers of weakly coupled [Pb2BiS3] and [AuTe2] sheets.

The Xer/dif site-specific recombination system of Campylobacter jejuni.

Chromosome dimers, which form during the bacterial life cycle, represent a problem that must be solved by the bacterial cell machinery so that chromosome segregation can occur effectively. The Xer/dif site-specific recombination system, utilized by most bacteria, resolves chromosome dimers into monomers using two tyrosine recombinases, XerC and XerD, to perform the recombination reaction at the dif site which consists of 28-30 bp. However, single Xer recombinase systems have been recently discovered in several bacterial species.

Characterization of the Streptococcus suis XerS recombinase and its unconventional cleavage of the difSL site.

XerC and XerD are members of the tyrosine recombinase family and mediate site-specific recombination that contributes to the stability of circular chromosomes in bacteria by resolving plasmid multimers and chromosome dimers to monomers prior to cell division. Homologues of xerC/xerD genes have been found in many bacteria, and in the lactococci and streptococci, a single recombinase called XerS can perform the functions of XerC and XerD. The xerS gene of Streptococcus suis was cloned, overexpressed and purified as a maltose-binding protein (MBP) fusion.