Mutations in the stator protein PomA affect switching of rotational direction in bacterial flagellar motor

The flagellar motor rotates bi-directionally in counter-clockwise (CCW) and clockwise (CW) directions. The motor consists of a stator and a rotor. Recent structural studies have revealed that the stator is composed of a pentameric ring of A subunits and a dimer axis of B subunits. Highly conserved charged and neighboring residues of the A subunit interacts with the rotor, generating torque through a gear-like mechanism. The rotational direction is controlled by chemotaxis signaling transmitted to the rotor, with less evidence for the stator being involved. In this study, we report novel mutations that affect the switching of the rotational direction at the putative interaction site of the stator to generate rotational force. Our results highlight an aspect of flagellar motor function that appropriate switching of the interaction states between the stator and rotor is critical for controlling the rotational direction

Physical properties of the Dome Fuji deep ice core (review)

Recent results of physical analyses of the Dome Fuji ice core are summarized with special attention to new methods introduced in the present studies. Microphysical processes which affect the ice core records are reviewed to better understand the paleoclimatic and paleoenvironmental signals stored

MORPHOLOGICAL AND CYTOCHEMICAL STUDIES ON THE SECRETORY GRANULES OF THE PYLORIC CAECA OF THE STARFISH, ASTERIAS AMURENSIS

Volume: 152Start Page: 64End Page: 7

Mutations in the stator protein PomA affect switching of rotational direction in bacterial flagellar motor

The flagellar motor rotates bi-directionally in counter-clockwise (CCW) and clockwise (CW) directions. The motor consists of a stator and a rotor. Recent structural studies have revealed that the stator is composed of a pentameric ring of A subunits and a dimer axis of B subunits. Highly conserved charged and neighboring residues of the A subunit interacts with the rotor, generating torque through a gear-like mechanism. The rotational direction is controlled by chemotaxis signaling transmitted to the rotor, with less evidence for the stator being involved. In this study, we report novel mutations that affect the switching of the rotational direction at the putative interaction site of the stator to generate rotational force. Our results highlight an aspect of flagellar motor function that appropriate switching of the interaction states between the stator and rotor is critical for controlling the rotational direction

The association of low serum magnesium levels with frailty among hemodialysis patients

Abstract Frailty is common among hemodialysis patients and is associated with mortality and fractures. Hypomagnesemia is also known to be a risk factor for mortality and fractures and has been shown to be significantly associated with muscle performance indexes. However, little is known about the association between hypomagnesemia and frailty. We enrolled 339 outpatients who underwent hemodialysis and assessed frailty using the Clinical Frailty Scale (CFS), a 7-point subjective assessment tool based upon clinical judgment. We examined the association between serum magnesium levels and frailty evaluated using the CFS. The median CFS score was 3 points, and 49 (14.5%) patients had frailty (CFS score ≥ 5). In multiple regression analysis, serum magnesium levels were independently associated with increased CFS scores (β = − 0.126, P = 0.005) adjusted for age, body mass index, diabetes, cardiovascular diseases, prevalent fractures, serum albumin and C-reactive protein. The adjusted odds ratio for frailty was 2.85 [95% confidence interval (CI) 1.23–6.97, P = 0.014] in the lower serum magnesium group categorized based on the median value. Furthermore, with regard to model discrimination, adding serum magnesium levels to the established risk factors significantly improved net reclassification (0.520, P < 0.001) and integrated discrimination (0.023, P = 0.031). Lower serum magnesium levels may be associated with the severity and definition of frailty independent of well-known risk factors

Impact of serum magnesium and bone mineral density on systemic fractures in chronic hemodialysis patients.

IntroductionBone mineral density (BMD) measured with dual-energy X-ray absorptiometry (DXA) can be used to predict fractures, but its clinical utility has not been fully established in chronic kidney disease (CKD) patients. Magnesium is an essential trace element. Although magnesium is associated with the risk of fractures in non-CKD populations, the relationship is unknown in CKD patients.MethodsBMD and serum magnesium levels were measured in 358 stable outpatients undergoing maintenance hemodialysis therapy. The primary outcome was fragility fracture. Patients were divided into groups according to the median level of magnesium and the normal threshold value of lumbar spine BMD.ResultsDuring the median follow-up period of 36 months, 36 (10.0%) fractures occurred. The cumulative incidence rates of fractures were 17.6% and 5.2% [adjusted hazard ratio (aHR) 2.31, 95% confidence interval (CI) 1.03-5.17, P = 0.030] in the lower (Discussion/conclusionsThe combination of serum magnesium and lumbar spine BMD can be used for fracture risk stratification and synergistically improves the prediction of fractures in CKD patients