Sökresultat

Filtyp

Din sökning på "*" gav 534729 sökträffar

Two-Step Selection of mRNAs in Initiation of Protein Synthesis

In a recent issue of Molecular Cell, Studer and Joseph (2006) clarified the molecular basis of the "standby model" and demonstrated how two-step binding of mRNAs to the small ribosomal subunit depends on initiator tRNA and initiation factors, with far-reaching implications for posttranscriptional regulation of gene expression.

Violating the thermodynamic uncertainty relation in the three-level maser

Nanoscale heat engines are subject to large fluctuations which affect their precision. The thermodynamic uncertainty relation (TUR) provides a trade-off between output power, fluctuations, and entropic cost. This trade-off may be overcome by systems exhibiting quantum coherence. This Letter provides a study of the TUR in a prototypical quantum heat engine, the Scovil–Schulz-DuBois maser. Compariso

Taurine effects on bisphenol a-induced oxidative stress in the mouse testicular mitochondria and sperm motility

Objectives: This study was performed to investigate the protective effects of taurine (2-aminoethanesulfonic acid, TAU) on oxidative stress in the isolated mouse testicular mitochondria, mitochondrial membrane potential (MMP), viability and motility of the exposed sperms to the BPA. Methods: We treated epididymal spermatozoa obtained from mice and isolated mouse testicular mitochondria with BPA (0

Crystallization of a Zr-based metallic glass produced by laser powder bed fusion and suction casting

The crystallization behaviour during low temperature annealing of samples of the Zr59.3Cu28.8Al10.4Nb1.5 (at%) bulk metallic glass produced by suction casting and the laser powder bed fusion (LPBF) process were studied with small angle neutron scattering (SANS), X-ray diffraction and scanning electron microscopy. The in-situ SANS measurements during isothermal annealing reveals that the phase sepa

Serum IFNα2 measured by single-molecule array associates with systemic disease manifestations in Sjögren's syndrome

OBJECTIVES: Type I IFN (IFN-I) activation is a prominent feature of primary SS (pSS), SLE, and SSc. Ultrasensitive single-molecule array (Simoa) technology has facilitated the measurement of subfemtomolar concentrations of IFNs. Here, we aimed to measure IFNα2 in serum from pSS, SLE, and SSc using a Simoa immunoassay and correlate these levels to blood IFN-stimulated gene (ISG) expression and dise

Target protection as a key antibiotic resistance mechanism

Antibiotic resistance is mediated through several distinct mechanisms, most of which are relatively well understood and the clinical importance of which has long been recognized. Until very recently, neither of these statements was readily applicable to the class of resistance mechanism known as target protection, a phenomenon whereby a resistance protein physically associates with an antibiotic t

The Rel stringent factor from Thermus thermophilus : Crystallization and X-ray analysis

The stringent response, controlled by (p)ppGpp, enables bacteria to trigger a strong phenotypic resetting that is crucial to cope with adverse environmental changes and is required for stress survival and virulence. In the bacterial cell, (p)ppGpp levels are regulated by the concerted opposing activities of RSH (RelA/SpoT homologue) enzymes that can transfer a pyrophosphate group of ATP to the 3′

The pretranslocation ribosome is targeted by GTP-bound EF-G in partially activated form

Translocation of the tRNA·mRNA complex through the bacterial ribosome is driven by the multidomain guanosine triphosphatase elongation factor G (EF-G). We have used isothermal titration calorimetry to characterize the binding of GDP and GTP to free EF-G at 4°C, 20°C, and 37°C. The binding affinity of EF-G is higher to GDP than to GTP at 4°C, but lower at 37°C. The binding enthalpy and entropy chan

Effect of kidney stem cells on inflammatory factors in rats with diabetic nephropathy

Mesenchymal stem cells (MSCs) were proposed as a critical therapeutic candidate in diabetic nephropathy (DN). Renal stem cells as a source for repairing are controversial. The purpose of the present study was to evaluate the effect of kidney rat stem cells on DN. After evaluation of surface stem cell markers by flow cytometry analysis, MSCs that were labeled with CM-Dil were injected to experiment

Fundamental relations for the velocity dispersion of stars in the Milky Way

We explore the fundamental relations governing the radial and vertical velocity dispersions of stars in the Milky Way, from combined studies of complementary surveys including GALAH, LAMOST, APOGEE, the NASA Kepler and K2 missions, and Gaia DR2. We find that different stellar samples, even though they target different tracer populations and employ a variety of age estimation techniques, follow the

Artificial gametes : perspectives of geneticists, ethicists and representatives of potential users

Several threads of research towards developing artificial gametes are ongoing in a number of research labs worldwide. The development of a technology that could generate gametes in vitro has significant potential for human reproduction, and raises a lot of interest, as evidenced by the frequent and extensive media coverage of research in this area. We have asked researchers involved in work with a

Transformative governance of biodiversity: insights for sustainable development : Transformative governance of biodiversity: insights for sustainable development

While there is much debate on transformative change among academics and policymakers, the discussion on how to govern such change is still in its infancy. This article argues that transformative governance is needed to enable the transformative change necessary for achieving global sustainability goals. Based on a literature review, the article unpacks this concept of transformative governance. It

The Alterations of Mitochondrial Function during NAFLD Progression : An Independent Effect of Mitochondrial ROS Production

The progression of non-alcoholic fatty liver (NAFL) into non-alcoholic steatohepatitis implicates multiple mechanisms, chief of which is mitochondrial dysfunction. However, the sequence of events underlying mitochondrial failure are still poorly clarified. In this work, male C57BL/6J mice were fed with a high-fat plus high-sucrose diet for 16, 20, 22, and 24 weeks to induce NAFL. Up to the 20th we

Leucine increases muscle mitochondrial respiration and attenuates glucose intolerance in diet-induced obesity in Swiss mice

Leucine is an essential amino acid that has been investigated by its participation in the regulation of whole-body metabolism and mitochondrial function. Here, we evaluated acute leucine effects on mitochondrial respiration of skeletal muscle from male Swiss mice in vitro. Additionally, we further investigated the effects of 4-wk leucine ingestion (2.5% on drinking water) on skeletal muscle mitoch

Prevalence of Subclinical Coronary Artery Atherosclerosis in the General Population

BACKGROUND: Early detection of coronary atherosclerosis using coronary computed tomography angiography (CCTA), in addition to coronary artery calcification (CAC) scoring, may help inform prevention strategies. We used CCTA to determine the prevalence, severity, and characteristics of coronary atherosclerosis and its association with CAC scores in a general population.METHODS: We recruited 30 154 r

An infrared study of Galactic OH/IR stars - III. Variability properties of the Arecibo sample

We present the results of a near-infrared (NIR) monitoring programme carried out between 1999 and 2005 to determine the variability properties of the 'Arecibo sample of OH/IR stars'. The sample consists of 385 IRAS-selected Asymptotic Giant Branch (AGB) candidates, for which their O-rich chemistry has been proven by the detection of 1612 MHz OH maser emission. The monitoring data were complemented

Associations between ambient particle radioactivity and lung function

Previous studies have suggested increased risk of respiratory diseases and mortality following short-term exposures to ionizing radiation. However, the short-term respiratory effects of low-level environmental radiation associated with air pollution particles have not been considered. Although ambient particulate matter (PM) has been reproducibly linked to decreased lung function and to increased