The functional roles of disulfide bonds in the β-subunit of (Na,K)ATPase as studied by site-directed mutagenesis

AbstractThe β-subunit of Torpedo californica (Na,K)ATPase contains seven cysteine residues; one (Cys46) is in the single transmembrane segment and the other six (Cys127, Cys150, Cys160, Cys176, Cys215 and Cys278) are in the extracellular domain and form three highly conserved disulfide bonds. Aβ-subunit mutant with replacement of Cys46 by Ser could assemble with the α-subunit, and the resulting αβ-complex was catalytically active. Mutants in which either the N-terminal side or both Cys residues of the Cys127-Cys150 bond were replaced by Ser could also tightly assemble with the α-subunit, but the resulting αβ-complex was catalytically inactive. On the other hand, disruption of either the Cys160-Cys176 or Cys215-Cys278 bond by substituting the N-terminal side only or both Cys residues with Ser led to a β-subunit that could not assemble with the α-subunit. We conclude that the structure of the β-subunit around the Cys160-Cys176 and Cys215-Cys278 loops is indispensable for assembly with the α-subunit, whereas the Cys127-Cys150 loop is not essential for assembly but is required for enzyme activity

Over-expression of cbaAB genes of Bacillus stearothermophilus produces a two-subunit SoxB-type cytochrome c oxidase with proton pumping activity

AbstractWe constructed expression plasmids containing cbaAB, the structural genes for the two-subunit cytochrome bo3-type cytochrome c oxidase (SoxB type) recently isolated from a Gram-positive thermophile Bacillus stearothermophilus.B. stearothermophilus cells transformed with the plasmids over-expressed an enzymatically active bo3-type cytochrome c oxidase protein composed of the two subunits, while the transformed Escherichia coli cells produced an inactive protein composed of subunit I without subunit II. The oxidase over-expressed in B. stearothermophilus was solubilized and purified. The oxidase contained protoheme IX and heme O, as the main low-spin heme and the high-spin heme, respectively. Analysis of the substrate specificity indicated that the high-affinity site is very specific for cytochrome c-551, a cytochrome c that is a membrane-bound lipoprotein of thermophilic Bacillus. The purified enzyme reconstituted into liposomal vesicles with cytochrome c-551 showed H+ pumping activity, although the efficiency was lower than those of cytochrome aa3-type oxidases belonging to the SoxM-type

Lower-stratospheric radiative damping and polar-night jet oscillation events

The effect of stratospheric radiative damping time scales on stratospheric variability and on stratosphere–troposphere coupling is investigated in a simplified global circulation model by modifying the vertical profile of radiative damping in the stratosphere while holding it fixed in the troposphere. Perpetual-January conditions are imposed, with sinusoidal topography of zonal wavenumber 1 or 2. The depth and duration of the simulated sudden stratospheric warmings closely track the lower-stratospheric radiative time scales. Simulations with the most realistic profiles of radiative damping exhibit extended time-scale recoveries analogous to polar-night jet oscillation (PJO) events, which are observed to follow sufficiently deep stratospheric warmings. These events are characterized by weak lower-stratospheric winds and enhanced stability near the tropopause, which persist for up to 3 months following the initial warming. They are obtained with both wave-1 and wave-2 topography. Planetary-scale Eliassen–Palm (EP) fluxes entering the vortex are also suppressed, which is in agreement with observed PJO events. Consistent with previous studies, the tropospheric jets shift equatorward in response to the warmings. The duration of the shift is closely correlated with the period of enhanced stability. The magnitude of the shift in these runs, however, is sensitive only to the zonal wavenumber of the topography. Although the shift is sustained primarily by synoptic-scale eddies, the net effect of the topographic form drag and the planetary-scale fluxes is not negligible; they damp the surface wind response but enhance the vertical shear. The tropospheric response may also reduce the generation of planetary waves, further extending the stratospheric dynamical time scales

Social Capital and Post-traumatic Stress Disorder among Heavy Rainfall and Flood Victims in Japan

This study examined the relationship between cognitive/structural social capital and post-traumatic stress disorder (PTSD) among victims of heavy rain and flood. Participants were individuals aged≥18 years affected by the July 2018 heavy rainfall in the cities of Kurashiki and Soja, Japan, and living in temporary housing. We distributed five copies of a questionnaire to 1,991 households and received responses from 1,927 individuals (907 men, 1,008 women, 12 respondents of unspecified sex) in 1,029 households (51.7%). We estimated odds ratios (ORs) and 95% confidence intervals (CIs) for associations between high (vs. low) social capital and PTSD or other outcomes. After covariate adjustment, the odds of having PTSD were lower in participants with high cognitive social capital than those with low cognitive social capital (OR=0.346, 95%CI: 0.263-0.456). Elderly women with higher structural social capital tended to have lower PTSD odds than those with lower structural social capital (OR=0.671, 95%CI: 0.431-1.046). The opposite pattern was observed for elderly men (OR=1.315, 95%CI: 0.792-2.183). Cognitive social capital is a protective factor that may reduce PTSD or promote a favorable PTSD prognosis after heavy rainfall and flood events. The associations between structural social capital and PTSD differ by age and sex

Predictability changes of stratospheric circulations in northern hemisphere winter

Practical predictability of the stratospheric circulation in the boreal winters during the period 2001–2006 has been examined using the archive of 1-month ensemble forecast datasets provided by the Japan Meteorological Agency. To investigate the predictability limit, two measures of the Root-Mean-Square Error (RMSE) and Anomaly Correlation (AC) have been used for the 10-hPa geopotential height field. In the winter stratosphere, an intermittent character of planetary wave activity causes two specific periods of the stratospheric circulation, i.e., an undisturbed phase with inactive planetary waves and a disturbed phase with active ones. Therefore, the predictability needs to be evaluated taking account of this feature. On the basis of careful consideration, the mean predictable period can be estimated to about 10 days during the disturbed phase; it is longer than the tropospheric predictable period of about 7 days. However, it exhibits large variability because of different growth rates of forecast errors caused by contributions of both wave and zonal-mean fields. During the undisturbed phase, the predictable period based on the AC is almost the same as that of the disturbed phase, although the predictable period based on the RMSE is extremely long, since the RMSE predictability is measured against the climatological standard deviation affected by disturbed phases. Therefore, the horizontal pattern of the stratospheric circulation is less predictable even though the forecast error is quite small

Paraplegia Caused by Multifocal Osteosarcoma With Spinal Lesions

Background: Multifocal osteosarcoma is a rare condition that may be either synchronous or metachronous. Spine involvement of multifocal osteosarcoma is very rare. Synchronous multifocal osteosarcoma is typically described as the occurrence of tumors at two or more sites in the absence of pulmonary metastases. Methods: A 55-year-old man initially presented with low back pain. Multiple osteosclerotic lesions were observed, primarily in the spine and pelvis, as well as in soft tissues. Lung lesions were observed, but they were relatively small at reference. Laboratory tests showed a markedly elevated alkaline phosphatase (ALP) level of 36, 416 U/L (normal range, 115-359 U/L). Based upon a diagnosis of osteosarcoma on biopsy, chemotherapy was administered, resulting in a decrease in ALP to 17, 833 U/L. Results: Decompression of the symptomatic compressed spinal cord and posterior spinal stabilization of T8-12 were performed. However, progressive extensions of multiple lesions to the spinal canal led to paraplegia with urinary dysfunction. Eleven months after the first visit to our hospital, the patient died due to multiple organ failure. Conclusions: Multifocal osteosarcoma accompanied by spinal lesions may lead to paraplegia, a clinical problem that negatively affects the quality of activities of daily living. Level of Evidence 4. Clinical Relevance: Multifocal osteosarcoma accompanied by spinal lesions may lead to paraplegia, a clinical problem that negatively affects the quality of life and activities of daily living

ADH Responses to Thoracic and Abdominal Surgery under Epidural Anesthesia

Changes of plasma ADH concentration were studied during thoracic and abdominal operations under epidural anesthesia comnbimed with nitrous oxide inhalation. In abdominal surgeries, ADH level was elevated by operative invasion as usually reported, significantly by peritoneal irritation particularly. In thoracic surgeries, on the other hand, ADH level showed a rise by operative invasion, but little significant change was observed by irritation to the pleura. There was no significant difference in ADH level between the high frequency positive-pressure ventilation group and the intermittent positive-pressure ventilation group

Administration of oxygen ultra-fine bubbles improves nerve dysfunction in a rat sciatic nerve crush injury model

Ultra-fine bubbles (<200 nm in diameter) have several unique properties and have been tested in various medical fields. The purpose of this study was to investigate the effects of oxygen ultra-fine bubbles (OUBs) on a sciatic nerve crush injury (SNC) model rats. Rats were intraperitoneally injected with 1.5 mL saline, OUBs diluted in saline, or nitrogen ultra-fine bubbles (NUBs) diluted in saline three times per week for 4 weeks in four groups: (1) control, (sham operation + saline); (2) SNC, (crush + saline); (3) SNC+OUB, (crush + OUB-saline); (4) SNC+NUB, (crush + NUB-saline). The effects of the OUBs on dorsal root ganglion (DRG) neurons and Schwann cells (SCs) were examined by serial dilution of OUB medium in vitro. Sciatic functional index, paw withdrawal thresholds, nerve conduction velocity, and myelinated axons were significantly decreased in the SNC group compared to the control group; these parameters were significantly improved in the SNC+OUB group, although NUB treatment did not affect these parameters. In vitro, OUBs significantly promoted neurite outgrowth in DRG neurons by activating AKT signaling and SC proliferation by activating ERK1/2 and JNK/c-JUN signaling. OUBs may improve nerve dysfunction in SNC rats by promoting neurite outgrowth in DRG neurons and SC proliferation.Matsuoka H., Ebina K., Tanaka H., et al. Administration of oxygen ultra-fine bubbles improves nerve dysfunction in a rat sciatic nerve crush injury model. International Journal of Molecular Sciences 19, 1395 (2018); https://doi.org/10.3390/ijms19051395

Three-dimensional electronic structure in ferromagnetic Fe3Sn2\textrm{Fe}_3\textrm{Sn}_2 with breathing kagome bilayers

A large anomalous Hall effect (AHE) has been observed in ferromagnetic $\textrm{Fe}_3\textrm{Sn}_2$ with breathing kagome bilayers. To understand the underlying mechanism for this, we investigate the electronic structure of $\textrm{Fe}_3\textrm{Sn}_2$ by angle-resolved photoemission spectroscopy (ARPES). In particular, we use both vacuum ultraviolet light (VUV) and soft x ray (SX), which allow surface-sensitive and relatively bulk-sensitive measurements, respectively, and distinguish bulk states from surface states, which should be unlikely related to the AHE. While VUV-ARPES observes two-dimensional bands mostly due to surface states, SX-ARPES reveals three-dimensional band dispersions with a periodicity of the rhombohedral unit cell in the bulk. Our data show a good consistency with a theoretical calculation based on density functional theory, suggesting a possibility that $\textrm{Fe}_3\textrm{Sn}_2$ is a magnetic Weyl semimetal.Comment: 6 pages, 4 figure