Rho controls actin cytoskeletal assembly in renal epithelial cells during ATP depletion and recovery

Actincytoskeletal disruption is a hallmark of ischemic injury and ATPdepletion in a number of cell types, including renal epithelial cells.We manipulated Rho GTPase signaling by transfection and microinjectionin LLC-PK proximal tubule epithelial cells and observed actincytoskeletal organization following ATP depletion or recovery byconfocal microscopy and quantitative image analysis. ATP depletionresulted in disruption of stress fibers, cortical F-actin, and apicalactin bundles. Constitutively active RhoV14 prevented disruption ofstress fibers and cortical F-actin during ATP depletion and enhancedthe rate of stress fiber reassembly during recovery. Conversely, theRho inhibitor C3 or dominant negative RhoN19 prevented recovery ofF-actin assemblies upon repletion. Actin bundles in the apicalmicrovilli and cytosolic F-actin were not affected by Rho signaling.Assembly of vinculin and paxillin into focal adhesions was disrupted byATP depletion, and constitutively active RhoV14, although protectingstress fibers from disassembly, did not prevent dispersion of vinculinand paxillin, resulting in uncoupling of stress fiber and focaladhesion assembly. We propose that ATP depletion causes Rhoinactivation during ischemia and that recovery of normalcellular architecture and function requires Rho.

     

Spermidine and abscisic acid-mediated phosphorylation of a cytoplasmic protein from rice root in response to salinity stress

Importance of higher polyamines, spermidine, and spermine, in relation to the mechanism and adaptation to combat abiotic stress has been well established in cereals. Owing to their polycationic nature at physiological pH, polyamines bind strongly to negative charges in cellular components such as nucleic acids, various proteins, and phospholipids. To study the physiological role of polyamine during salinity stress, phosphorylation study was carried out in cytosolic soluble protein fraction isolated from the roots of salt tolerant (Nonabokra) and salt sensitive (M-1-48) rice cultivars treated with none (control), NaCl (150 mM, 16 h), spermidine (1 mM, 16 h) or with abscisic acid (100 μM, 16 h). A calcium independent auto regulatory 42 kDa protein kinase was found to phosphorylate myelin basic protein and casein but not histone. Interestingly, this was the only protein to be phosphorylated in root cytosolic fraction during NaCl/abscisic acid/spermidine treatment indicating its importance in salinity mediated signal transduction. This is the first report of polyamine as well as abscisic acid induced protein kinase activity in rice root in response to salinity stress.     

Moderate Alcohol Use and Cardiovascular Disease from Mendelian Randomization

Background

Observational studies show moderate alcohol use negatively associated with ischemic heart disease (IHD) and cardiovascular disease (CVD). However, healthier attributes among moderate users compared to never users may confound the apparent association. A potentially less biased way to examine the association is Mendelian randomization, using alcohol metabolizing genes which influence alcohol use.

Methods

We used instrumental variable analysis with aldehyde dehydrogenase 2 (ALDH2) genotypes (AA/GA/GG) as instrumental variables for alcohol use to examine the association of alcohol use (10 g ethanol/day) with CVD risk factors (blood pressure, lipids and glucose) and morbidity (self-reported IHD and CVD) among men in the Guangzhou Biobank Cohort Study.

Results

ALDH2 genotypes were a credible instrument for alcohol use (F-statistic 74.6). Alcohol was positively associated with HDL-cholesterol (0.05 mmol/L per alcohol unit, 95% confidence interval (CI) 0.02 to 0.08) and diastolic blood pressure (1.15 mmHg, 95% CI 0.23 to 2.07) but not with systolic blood pressure (1.00 mmHg, 95% CI -0.74 to 2.74), LDL-cholesterol (0.03 mmol/L, 95% CI -0.03 to 0.08), log transformed triglycerides (0.03 mmol/L, 95% CI -0.01 to 0.08) or log transformed fasting glucose (0.01 mmol/L, 95% CI -0.006 to 0.03), self-reported CVD (odds ratio (OR) 0.98, 95% CI 0.76 to 1.27) or self-reported IHD (OR 1.10, 95% CI 0.83 to 1.45).

Conclusion

Low to moderate alcohol use among men had the expected effects on most CVD risk factors but not fasting glucose. Larger studies are needed to confirm the null associations with IHD, CVD and fasting glucose.     

Nucleosomal Positioning and Genetic Divergence Study Based on DNA Flexibility Map

Abstract

Based on worm like chain model, DNA structural parameters—tilt, roll and rise, derived from crystallographic database have been used to determine the flexibility of DNA that regulates the nucleosomal translational positioning. Theoretically derived data has been compared to the experimental values available in Ioshikhes and Trifonov's database. The methodology has been extended to determine the flexibility of 18S rRNA genome in eukarya, where yeast shows a distinct difference when compared with mammals like human, mouse and rabbit.     

In-vivo dose measurements with MOSFET dosimeters during MV portal imaging

BackgroundThe purpose of this study was to investigate the feasibility of MOSFET dosimeter in measuring eye dose during 2D MV portal imaging for setup verification in radiotherapy.Materials and methodsThe in-vivo dose measurements were performed by placing the dosimeters over the eyes of 30 brain patients during the acquisition of portal images in linear accelerator by delivering 1 MU with the field sizes of 10 × 10 cm² and 15 × 15 cm².ResultsThe mean doses received by the left and right eyes of 10 out of 30 patients when both eyes were completely inside the anterior portal field were found to be 2.56 ± 0.2 cGy and 2.75 ± 0.2, respectively. Similarly, for next 10 patients out of the same 30 patients the mean doses to left and right eyes when both eyes were completely out of the anterior portal fields were found to be 0.13 ± 0.02 cGy and 0.17 ± 0.02 cGy, respectively. The mean doses to ipsilateral and contralateral eye for the last 10 patients when one eye was inside the anterior portal field were found to be 3.28 ± 0.2 cGy and 0.36 ± 0.1 cGy, respectively.ConclusionThe promising results obtained during 2D MV portal imaging using MOSFET have shown that this dosimeter is well suitable for assessing low doses during imaging thereby enabling to optimize the imaging procedure using the dosimetric data obtained. In addition, the documentation of the dose received by the patient during imaging procedure is possible with the help of an in-built software in conjunction with the MOSFET reader module.     

The pygmy hog is a unique genus: 19th century taxonomists got it right first time round

The pygmy hog, Sus salvanius, the smallest and rarest extant suid was first described as the only member of the genus Porcula. It is currently regarded as member of the genus Sus and a sister taxon of the domestic pig/Eurasian wild boar (Sus scrofa). Phylogenetic analyses of 2316 bp from three mtDNA loci (control-region, cytochrome b, 16S) by Bayesian inference and statistical testing of alternative phylogenetic hypotheses all support the original classification of the pygmy hog as a unique genus. Thus, we propose that the species name Porcula salvania should be resurrected. The reclassification will heighten awareness of the need for the future protection and survival of this unique species.     

Antidiabetic potential of Citrus sinensis and Punica granatum peel extracts in alloxan treated male mice

An investigation on the effects of four different concentrations of peel extract from Citrus sinensis (CS) or Punica granatum (PG) in male mice revealed the maximum glucose lowering and antiperoxidative activities at 25 mg/kg of CS and 200 mg/kg of PG. In a separate experiment their potential was evaluated with respect to the regulation of alloxan induced diabetes mellitus. While a single dose of alloxan (120 mg/kg) increased the serum levels of glucose and alpha-amylase activity, rate of water consumption and lipid peroxidation (LPO) in hepatic, cardiac and renal tissues with a parallel decrease in serum insulin level, administration of 25 mg/kg of CS or 200 mg/kg of PG was found to normalize all the adverse changes induced by alloxan, revealing the antidiabetic and anti peroxidative potential of test fruit peel extracts. Subsequent phytochemical analysis indicated that the high content of total polyphenols in the test peels might be related to the antidiabetic and antiperoxidative effects of the test peels.     

Production of xylanase by immobilized Trichoderma reesei SAF3 in Ca-alginate beads

In the present study, the optimum conditions for the production of xylanase by immobilized spores of Trichoderma reesei SAF3 in calcium alginate beads were determined. The operational stability of the beads during xylanase production under semi-continuous fermentation was also studied. The influence of alginate concentration (1, 2, 3, and 4%) and initial cell loading (100, 200, 300, 400, and 500 beads per flask) on xylanase production was considered. The production of xylanase was found to increase significantly with increasing concentration of alginate and reached a maximum yield of 3.12 ± 0.18 U ml⁻¹ at 2% (w/v). The immobilized cells produced xylanase consistently up to 10 cycles and reached a maximum level at the forth cycle (3.36 ± 0.2 U ml⁻¹).     

Gender dependent cervical spine segmental kinematics during whiplash

Clinical and epidemiological studies have frequently reported that female occupants sustain whiplash injuries more often than males. The current study was based on the hypothesis that segmental level-by-level cervical intervertebral motions in females are greater than in males during rear impact. The hypothesis was tested by subjecting 10 intact human cadaver head-neck complexes (five males, five females) to rear impact loading. Intervertebral kinematics were analyzed as a function of spinal level at the time of maximum cervical S-curve, which occurred during the loading phase. Segmental angles were significantly greater (p<0.05) in female specimens at C2-C3, C4-C5, C5-C6, and C6-C7 levels. Because greater angulations are associated with stretch in the innervated components of the cervical spinal column, these findings may offer a biomechanical explanation for the higher incidence of whiplash-related complaints in female patients secondary to rear impact acceleration.     

Stimulation of protein kinase C modulates insulin-like growth factor-1-induced akt activation in PC12 cells

Activation of protein kinase C (PKC) plays an important role in the negative regulation of receptor signaling, but its effect on insulin-like growth factor-1 (IGF-1) receptor signaling remains unclear. In this study, we characterized the intracellular pathways involved in IGF-1-induced activation of Akt and evaluated the effects of the PKC activator phorbol 12-myristate 13-acetate (PMA) on the Akt activation by IGF-1. IGF-1 induced a time- and concentration-dependent activation of Akt. The effect of IGF-1 was blocked by the phosphatidylinositide 3-kinase (PI3K) inhibitors LY294002 (50 micrometer) and wortmannin (0.5 micrometer), but not by the MEK inhibitor PD98059 (50 micrometer) or the p70 S6 kinase pathway inhibitor rapamycin (50 nm), suggesting that the stimulation of Akt by IGF-1 is mediated by the PI3K pathway. Interestingly, cotreatment with PMA (400 nm) attenuated IGF-1-induced activation of Akt. The attenuation was blocked completely by the PKC inhibitor GO6983 (0.5 micrometer), but only partially by the MEK inhibitor PD98059 (50 micrometer), indicating that MAPK-dependent and -independent pathways are involved. PMA induced the activation of PKC in PC12 cells, and this induction was blocked by GO6983. These data further support the role of PKC in the effect of PMA. Moreover, PKCdelta is likely involved in the action of PMA on the basis of data obtained using isoform-specific inhibitors such as rottlerin. PMA also decreased IGF-1-induced tyrosine phosphorylation of insulin receptor substrate-1 and its association with PI3K. Taken together, these results suggest, for the first time, that stimulation of PKC modulates IGF-1-induced activation of Akt.