Deacetylation of HSD17B10 by SIRT3 regulates cell growth and cell resistance under oxidative and starvation stresses.

17-beta-hydroxysteroid dehydrogenase 10 (HSD17B10) plays an important role in mitochondrial fatty acid metabolism and is also involved in mitochondrial tRNA maturation. HSD17B10 missense mutations cause HSD10 mitochondrial disease (HSD10MD). HSD17B10 with mutations identified from cases of HSD10MD show loss of function in dehydrogenase activity and mitochondrial tRNA maturation, resulting in mitochondrial dysfunction. It has also been implicated to play roles in the development of Alzheimer disease (AD) and tumorigenesis. Here, we found that HSD17B10 is a new substrate of NAD-dependent deacetylase Sirtuin 3 (SIRT3). HSD17B10 is acetylated at lysine residues K79, K99 and K105 by the acetyltransferase CBP, and the acetylation is reversed by SIRT3. HSD17B10 acetylation regulates its enzymatic activity and the formation of mitochondrial RNase P. Furthermore, HSD17B10 acetylation regulates the intracellular functions, affecting cell growth and cell resistance in response to stresses. Our results demonstrated that acetylation is an important regulation mechanism for HSD17B10 and may provide insight into interrupting the development of AD

Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

New design of external heat-ratio method for measuring low and reverse rates of sap flow in thin stems

Sap-flow techniques had limited application to thin-stemmed woody and herbaceous species and to diverse functional plant organs until the recent development of the external heat-ratio (EHR) method. Existing EHR techniques using miniature&nbsp;gauge&nbsp;configurations, however, are limited to thin&nbsp;stems&nbsp;with diameters of 2&ndash;5 mm. This study introduces a new design of an EHR gauge adapted to thin stems with diameters up to 15 mm and sap-flux densities &lt;50 cm h&minus;1. The gauge was calibrated on cut stems of the shrubs&nbsp;Caragana korshinskii&nbsp;and&nbsp;Salix psammophila, with the measured heat-pulse velocity (Vh) compared to gravimetric measurements of sap-flux density (Vs) under controlled conditions. A validation test was also carried out by comparing EHR method with the stem heat-balance (SHB) method through in situ and long-term monitoring of&nbsp;Vs&nbsp;on standing stems of&nbsp;C. korshinskii.&nbsp;Vh&nbsp;in the tested cut stems of both species was linearly correlated with&nbsp;Vs&nbsp;up to approximately 50 cm h&minus;1&nbsp;(R2&nbsp;up to 0.96,&nbsp;P &lt; 0.001) in a range of stem diameters of 4.1&ndash;15.6 mm. An empirical multiplier for converting the measured&nbsp;Vh&nbsp;to&nbsp;Vs, however, varied between the two species, 2.02 and 1.15 for&nbsp;C. korshinskii&nbsp;and&nbsp;S.&nbsp;psammophila, respectively. The EHR technique sensitively captured the diurnal dynamics of&nbsp;Vs&nbsp;in&nbsp;field&nbsp;tests, within a range from zero to nearly 30 cm h&minus;1&nbsp;on&nbsp;C. korshinskii&nbsp;stems, and hourly&nbsp;Vs&nbsp;was linearly correlated with the reference evapotranspiration (R2 = 0.70,&nbsp;P &lt; 0.001) over 26 successive days without drought stress. The tested SHB method, however, poorly detected the sap-flux density, especially at low densities. The gauges for the EHR method were easy to build and capable of accurate estimating bidirectional sap flow, especially at low densities. This technique, with variable EHR gauge configurations, has broader applications than SHB methods for understanding plant-water relations in understories, shrubs and ecosystems dominated by herbage.</p

Ultrafast vibrational dynamics of the tyrosine ring mode and its application to enkephalin insertion into phospholipid membranes as probed by two-dimensional infrared spectroscopy.

Enkephalins are small opioid peptides whose binding conformations are catalyzed by phospholipid membranes. Binding to opioid receptors is determined by the orientation of tyrosine and phenylalanine side chains. In this work, we investigate the effects of different charged phospholipid headgroups on the insertion of the tyrosine side chain into a lipid bilayer using a combination of 2D IR spectroscopy, anharmonic DFT calculations, and third order response function modeling. The insertion is probed by using the ∼1515&nbsp;cm-1 tyrosine ring breathing mode, which we found exhibits rich vibrational dynamics on the picosecond timescale. These dynamics include rapid intramolecular vibrational energy redistribution (IVR), where some of the energy ends up in a dark state that shows up as an anharmonically shifted combination band. The waiting-time dependent 2D IR spectra also show an unusual line shape distortion that affects the extraction of the frequency-frequency correlation function (FFCF), which is the dynamic observable of interest that reflects the tyrosine side chain's insertion into the lipid bilayer. We proposed three models to account for this distortion: a hot-state exchange model, a local environment dependent IVR model, and a coherence transfer model. A qualitative analysis of these models suggests that the local environment dependent IVR rate best explains the line shape distortion, while the coherence transfer model best reproduced the effects on the FFCF. Even with these complex dynamics, we found that the tyrosine ring mode's FFCF is qualitatively correlated with the degree of insertion expected from the different phospholipid headgroups

Effects of Extraction Technique on the Content and Antioxidant Activity of Flavonoids from Gossypium Hirsutum linn. Flowers

Cotton is one of the Uyghur medical materials in China and is rich in flavonoids. Flavonoids have important pharmacological effects. The yield of flavonoids in traditional extraction methods is low, which affects the development of flavonoids. Therefore, it is urgent to optimize the extraction techniques. The yield of flavonoids in cotton flowers was effectively improved by response surface methodology, and the highest yield of flavonoids reached 5.66%, and the optimal extraction process conditions were obtained. The DPPH free radical scavenging rate, hydroxyl free radical scavenging rate, superoxide anion free radical scavenging rate, and reducing ability were tested to reflect the antioxidant capacity of flavonoids. The flavonoids had an excellent antioxidant effect. Cell experiments suggested that the flavonoids had the effect of protecting glutamate-induced damage to HT-22 cells. The results of this study provide a theoretical basis for the extraction of cotton flowers flavonoids and the comprehensive evaluation of antioxidant products, as well as the extraction of other plant flavonoids

iRhom2 loss alleviates renal injury in long-term PM2.5-exposed mice by suppression of inflammation and oxidative stress

Particulate matter (PM2.5) is a risk factor for organ injury and disease progression, such as lung, brain and liver. However, its effects on renal injury and the underlying molecular mechanism have not been understood. The inactive rhomboid protein 2 (iRhom2), also known as rhomboid family member 2 (Rhbdf2), is a necessary modulator for shedding of tumor necrosis factor-α (TNF-α) in immune cells, and has been explored in the pathogenesis of chronic renal diseases. In the present study, we found that compared to the wild type (iRhom2+/+) mice, iRhom2 knockout (iRhom2-/-) protected PM2.5-exposed mice from developing severe renal injury, accompanied with improved renal pathological changes and functions. iRhom2-/- mice exhibited reduced inflammatory response, as evidenced by the reduction of interleukin 1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α) and IL-18 in kidney samples, which might be, at least partly, through inactivating TNF-α converting enzyme/TNF-α receptors (TACE/TNFRs) and inhibitor of α/nuclear factor κ B (IκBα/NF-κB) signaling pathways. In addition, oxidative stress was also restrained by iRhom2-/- in kidney of PM2.5-exposed mice by enhancing heme oxygenase/nuclear factor erythroid 2-related factor 2 (HO-1/Nrf-2) expressions, and reducing phosphorylated c-Jun N-terminal kinase (JNK). In vitro, blockage of HO-1 or Nrf-2 rescued the inflammatory response and oxidative stress that were reduced by iRhom2 knockdown in PM2.5-incubated RAW264.7 cells. Similar results were observed in JNK activator-treated cells. Taken together, our findings indicated that iRhom2 played an essential role in regulating PM2.5-induced chronic renal damage, thus revealing a potential target for preventing chronic kidney diseases development. Keywords: PM2.5, Renal injury, iRhom2, Inflammation, Oxidative stress, JN

Role of the X and n factors in ion-irradiation induced phase transformations of M(n+1)AX(n) phases

Phase transitions induced in hcp M(n+1)AX(n) phases (Ti2AlN, Ti2AlC, and Ti4AlN3) by 1 MeV Au+ ion irradiation were investigated, over a series of ion fluences ranging from 1 x 10(14) to 2 x 10(16) ions cm(-2), by transmission electron microscopy (TEM) and synchrotron grazing incidence X-ray diffraction (GIXRD). Irradiation-induced structural evolutions were observed using high-resolution TEM (HRTEM) imaging and selected area electron diffraction (SAED). Based on phase contrast imaging and electron diffraction pattern (EDP) simulations, the atomic-scale mechanisms for the phase transitions were determined. Transformations of the initial hcp phases to the intermediate gamma-phases and fcc phases were driven by the formation of Ti/Al antisite defects and extended stacking faults induced by ion irradiation. By comparing the transformation behavior of Ti2AlN with that of Ti2AlC and Ti4AlN3 under the same irradiation conditions, using both the experimental data and first-principles calculations, the role of the X and n parameters in the radiation responses of M(n+1)AX(n) phases were elucidated. The susceptibilities of materials in this Ti-Al-X (X = C, N) system to irradiation-induced phase transitions were determined with respect to the bonding characteristics and compositions of these MAX phases. Ti2AlC is slightly less susceptible to the radiation-induced phase transformation than Ti2AlN, which is attributed to the stronger Ti-Al bond covalency in Ti2AlN. Ti4AlN3 is more resistant to radiation-induced phase transformations than is Ti2AlN, due to the lower Al content and lower anion vacancy ratio in the irradiation-induced solid solution phases. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

The deubiquitinating enzyme 13 retards non-alcoholic steatohepatitis via blocking inactive rhomboid protein 2-dependent pathway

Nowadays potential preclinical drugs for the treatment of nonalcoholic steatohepatitis (NASH) have failed to achieve expected therapeutic efficacy because the pathogenic mechanisms are underestimated. Inactive rhomboid protein 2 (IRHOM2), a promising target for treatment of inflammation-related diseases, contributes to deregulated hepatocyte metabolism-associated nonalcoholic steatohepatitis (NASH) progression. However, the molecular mechanism underlying Irhom2 regulation is still not completely understood. In this work, we identify the ubiquitin-specific protease 13 (USP13) as a critical and novel endogenous blocker of IRHOM2, and we also indicate that USP13 is an IRHOM2-interacting protein that catalyzes deubiquitination of Irhom2 in hepatocytes. Hepatocyte-specific loss of the Usp13 disrupts liver metabolic homeostasis, followed by glycometabolic disorder, lipid deposition, increased inflammation, and markedly promotes NASH development. Conversely, transgenic mice with Usp13 overexpression, lentivirus (LV)- or adeno-associated virus (AAV)-driven Usp13 gene therapeutics mitigates NASH in 3 models of rodent. Mechanistically, in response to metabolic stresses, USP13 directly interacts with IRHOM2 and removes its K63-linked ubiquitination induced by ubiquitin-conjugating enzyme E2N (UBC13), a ubiquitin E2 conjugating enzyme, and thus prevents its activation of downstream cascade pathway. USP13 is a potential treatment target for NASH therapy by targeting the Irhom2 signaling pathway