Role of fungal laccase in iodide oxidation in soils

Publication date: September 2018
Source:Journal of Environmental Radioactivity, Volume 189
Author(s): Reiko Nihei, Mizuki Usami, Taro Taguchi, Seigo Amachi
Previously, we hypothesized that microbial laccase oxidizes iodide (I⁻) in soils to molecular iodine (I2) or hypoiodous acid (HIO), both of which are easily incorporated into natural soil organic matter, and thus plays a role in iodine sorption on soils. In this study, soil iodide oxidase activity was determined by a colorimetric assay to evaluate if laccase is responsible for iodide oxidation in soils. Three types of Japanese soil showed significant iodide oxidase activities (0.751–2.87 mU g soil⁻¹) at pH 4.0, which decreased with increasing pH, until it was no longer detected at pH 5.5. The activity was inhibited strongly by autoclaving or by the addition of common laccase inhibitors. Similar tendency of inhibition was observed in soil laccase activity, which was determined with 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as a substrate. Significant positive correlations (R² values of 0.855–0.896) between iodide oxidase activity and laccase activity were observed in two of three soils. Commercially available fungal laccases showed only very low iodide oxidase activities (4.68–18.0 mU mg⁻¹), but enhanced activities of 102–739 mU mg⁻¹ were observed in the presence of redox mediators. Finally, we successfully isolated fungal strains with iodide-oxidizing phenotype in the presence of redox mediators. Polyacrylamide gel electrophoresis of the culture supernatant of Scytalidium sp. strain UMS and subsequent active stain revealed that the fungal laccase actually oxidized iodide in the presence of redox mediators. These results suggest that at least part of iodide in soils is oxidized by fungal laccase through the laccase-mediator system.



from Radiology via xlomafota13 on Inoreader https://ift.tt/2HnfXy0
via IFTTT

Radiocesium interaction with clay minerals: Theory and simulation advances Post–Fukushima

Publication date: September 2018
Source:Journal of Environmental Radioactivity, Volume 189
Author(s): Masahiko Okumura, Sebastien Kerisit, Ian C. Bourg, Laura N. Lammers, Takashi Ikeda, Michel Sassi, Kevin M. Rosso, Masahiko Machida
Insights at the microscopic level of the process of radiocesium adsorption and interaction with clay mineral particles have improved substantially over the past several years, triggered by pressing social issues such as management of huge amounts of waste soil accumulated after the Fukushima Dai–ichi nuclear power plant accident. In particular, computer–based molecular modeling supported by advanced hardware and algorithms has proven to be a powerful approach. Its application can now generally encompass the full complexity of clay particle adsorption sites from basal surfaces to interlayers with inserted water molecules, to edges including fresh and weathered frayed ones. On the other hand, its methodological schemes are now varied from traditional force–field molecular dynamics on large–scale realizations composed of many thousands of atoms including water molecules to first–principles methods on smaller models in rather exacting fashion. In this article, we overview new understanding enabled by simulations across methodological variations, focusing on recent insights that connect with experimental observations, namely: 1) the energy scale for cesium adsorption on the basal surface, 2) progress in understanding the structure of clay edges, which is difficult to probe experimentally, 3) cesium adsorption properties at hydrated interlayer sites, 4) the importance of the size relationship between the ionic radius of cesium and the interlayer distance at frayed edge sites, 5) the migration of cesium into deep interlayer sites, and 6) the effects of nuclear decay of radiocesium. Key experimental observations that motivate these simulation advances are also summarized. Furthermore, some directions toward future solutions of waste soil management are discussed based on the obtained microscopic insights.



from Radiology via xlomafota13 on Inoreader https://ift.tt/2vgUWQM
via IFTTT

The spatial and developmental expression of mouse Vwa8 (von Willebrand domain-containing protein 8)

Publication date: Available online 13 April 2018
Source:Gene Expression Patterns
Author(s): Brian S. Grewe, Janet E. Richmond, David E. Featherstone
The Drosophila gene c12.2 was isolated in a screen examining mRNA binding proteins. Drosophila c12.2 is the mouse Vwa8 homolog. Various genome-wide associated studies have linked human Vwa8 to both neurological and oncological pathologies, which include autism, bipolar disorder, comorbid migraine, and acute myeloid leukemia, however, the function and role of the VWA8 protein remain poorly understood. To further analyze the Vwa8 gene in mouse, gene structure, protein homology modeling, and gene expression patterns were examined throughout mouse development. Our analyses indicate that the mouse Vwa8 gene produces two transcripts; the full-length Vwa8a is highly expressed relative to the truncated Vwa8b transcript across all developmental time points and tissues analyzed. Protein homology modeling indicates that VWA8a belongs to a novel protein superfamily containing both the midasin and cytoplasmic dynein 1 heavy chain 1 proteins. These data establish the development timeline and expression profile for both Vwa8a and Vwa8b, paving the way for future studies to determine the cellular role(s) of this highly conserved protein family.



from Genetics via xlomafota13 on Inoreader https://ift.tt/2qsYwm8
via IFTTT

Differences in Hip and Knee Running Moments across Female Pubertal Development

Purpose This study aimed to investigate whether knee and hip running moments differ across stages of female pubertal development. Methods This was a cross-sectional study comparing the barefoot running moments of 91 prepubertal (n = 31, Tanner stage I), early/midpubertal (n = 30, Tanner stages II and III), and late/postpubertal (n = 30, Tanner stages IV and V) girls. External peak moments for knee abduction (KAbM), knee adduction (KAM), knee flexion (KFM), and knee internal rotation (KIRM) were analyzed. Secondary measures of hip adduction moment at the time of peak KAbM and hip flexion moment at the time of peak KFM were also derived. Between-group differences were analyzed using a series of one-way ANOVAs and ANCOVAs. Results At the knee, the late/postpubertal girls displayed a higher peak KFM and KAM compared with the prepubertal group (P 0.05). At the hip, both the late/postpubertal (P = 0.03) and early/midpubertal girls (P = 0.039) ran with a lower hip adduction moment at the time of peak KAbM than the prepubertal girls. The hip flexion moment at the time of peak KFM in late/postpubertal girls was also significantly lower than both the early/mid- and prepubertal girls (P

from Sports Medicine via xlomafota13 on Inoreader https://ift.tt/2GX7qT3
via IFTTT

Protocol for Objective Measurement of Infants’ Physical Activity using Accelerometry

Purpose This study aimed to evaluate methods for infants' physical activity measurement based on accelerometry, including the minimum number of measurement days and placement of a wrist or ankle device. We also evaluated the acceptability of the device among infants and mothers. Methods A cross-sectional mixed-methods study was conducted on a convenience sample of 90 infants. Physical activity was measured using the Actigraph GT3X+ accelerometer placed on the wrist and/or ankle for 7 consecutive days (worn for 24 h), and a qualitative interview was performed to verify acceptability. The intraclass correlation coefficient (ICC) method and the Bland and Altman's dispersion diagram were used to verify the minimum number of measurement days. All analyses were stratified by walking status. Results The mean (SD) age was 12.9 (1.70) months; the mean acceleration varied between 25.8 mg (95% confidence interval (CI), 14.3–52.7) and 27.3 mg (95% CI, 17.9–44.5) using the wrist placement, and between 24.9 mg (95% CI, 10.6–48.4) and 26.2 mg (95% CI, 11.7–65.6) using the ankle placement. The ICC results showed a lower acceleration variability between days among infants incapable of walking; they achieved an ICC of 0.80 with 1 d of measurement in both placements. Among those capable of walking, the minimum number of days to achieve an ICC of 0.80 was 2 d measured at the wrist (0.85; 95% CI, 0.71–0.93) and 3 d measured at the ankle (0.92; 95% CI, 0.84–0.96). The qualitative results pointed to the wrist placement as the preferred placement among the overall sample. Conclusions Two and three measurement days with the accelerometer placed on the wrist and ankle, respectively, seemed to adequately represent a week of measurement. The accelerometer placed on the wrist had better acceptance by the infants and mothers.

from Sports Medicine via xlomafota13 on Inoreader https://ift.tt/2qwvYaB
via IFTTT

Effect of Beta-blocker Treatment on V˙O2peak in Patients with Heart Failure

Purpose In addition to prolonged life and reduced hospitalization rates, it is currently unclear whether beta-blocker (BB) treatment modulates peak oxygen consumption (V˙O2peak), a hallmark of exercise capacity, in patients with heart failure (HF). The main aim of this study is to determine the effect of BB treatment on V˙O2peak in HF patients. Methods We conducted a systematic search of MEDLINE, Scopus, and Web of Science since their inceptions until March 2017 for randomized controlled trials (RCT) assessing the effect of BB treatment on V˙O2peak in chronic HF patients. A meta-analysis was performed to ascertain the standardized mean difference (SMD) between the effects of BB and placebo treatment on V˙O2peak. Secondary outcomes included peak exercise performance and New York Health Association functional class. Subgroup and meta-regression analyses assessed potential moderating factors. Results Fourteen RCT met the inclusion criteria (overall n = 616). Interventions comprised BB (n = 324) or placebo (n = 292) administration lasting 3 to 24 months. Concomitant reported medication did not differ between HF patients assigned to BB and placebo groups. After data pooling, V˙O2peak was preserved with BB compared with placebo treatment (SMD, −0.04; 95% confidence interval (CI), −0.20 to 0.12; P = 0.61); heterogeneity among studies was not detected (I2 = 0%, P = 0.88). Peak exercise performance was not altered (SMD, 0.02; 95% CI, −0.16 to 0.20; P = 0.85), whereas New York Health Association functional class was reduced with BB compared with placebo (SMD, −0.54; 95% CI, −0.90 to −0.18; P = 0.003). Conclusions According to evidence from RCT, prolonged BB (B1-selective or nonselective) treatment does not affect V˙O2peak but improves functional status in HF patients.

from Sports Medicine via xlomafota13 on Inoreader https://ift.tt/2GWpOLH
via IFTTT

Synchronizing Gait with Cardiac Cycle Phase Alters Heart Rate Response during Running

Timing foot strike to occur in synchrony with cardiac diastole may reduce left ventricular afterload and promote coronary and skeletal muscle perfusion. Purpose This study aimed to assess heart rate (HR) and metabolic responses to running when foot strikes are timed to occur exclusively during 1) the systolic phase of the cardiac cycle or 2) the diastolic phase. Methods Ten elite male distance runners performed a testing session on a treadmill at 4.72 m·s−1 while matching their steps to an auditory tone and wearing a chest strap that transmitted accelerometer and ECG signals. Testing comprised eight prompted 3-min stages, where a real-time adaptive auditory tone guided subjects to step with each ECG R-wave (systolic stepping) or alternatively, at 45% of each R-R interval (diastolic stepping), followed by a 3-min unprompted control stage. Metabolic variables were measured continuously. Results HR (P

from Sports Medicine via xlomafota13 on Inoreader https://ift.tt/2qtRo7W
via IFTTT