Quercetin protects human granulosa cells against oxidative stress via thioredoxin system

Granulosa Cells (GCs) are sensitive to excessive production of reactive oxygen species (ROS). Quercetin (QUR) is a free radical scavenger which can alleviate oxidative stress through nuclear factor (erythroid-derived 2)-like 2 (Nrf2)/antioxidant response element (ARE) pathway and thioredoxin (Trx) system. We aimed to explore the probable protective role of QUR on cultured human GCs treated with hydrogen peroxide (H₂O₂) as an inducer of oxidative stress. MTT assay was applied for evaluating the cell cytotoxicity of QUR and H₂O₂. The rate of apoptotic cells and intracellular ROS generation were determined by Annexin V-FITC/PI staining and 2′-7′-dichlorodihydro?uorescein diacetate ?uorescent probes (DCFH-DA), respectively. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis and western blot analysis were used to evaluate the gene and protein expression of Nrf2 and kelch-like ech-associated protein 1 (Keap1)1. The Nrf2 and Trx activities were measured by Enzyme-linked Immunosorbent Assay (ELISA). The results indicated that QUR pretreatment can decrease ROS production and apoptosis induced by H₂O₂. In addition, QUR increased Nrf2 gene and protein expression, as well as its nuclear translocation. Moreover, in QUR-treated group, a lower level of Keap1 protein was observed, which was not reported as significant. The results also indicated a significant correlation between the expression of Nrf2 and Keap1 in QUR-treated group. Further, QUR protected GCs from oxidative stress by increasing Trx gene expression and activity. This study suggests that QUR as a supplementary factor may protect GCs from oxidative stress in diseases related to this condition.     

A packed bed membrane reactor for production of biodiesel using activated carbon supported catalyst

In this study, a novel continuous reactor has been developed to produce high quality methyl esters (biodiesel) from palm oil. A microporous TiO₂/Al₂O₃ membrane was packed with potassium hydroxide catalyst supported on palm shell activated carbon. The central composite design (CCD) of response surface methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst amount and cross flow circulation velocity on the production of biodiesel in the packed bed membrane reactor. The highest conversion of palm oil to biodiesel in the reactor was obtained at 70 °C employing 157.04 g catalyst per unit volume of the reactor and 0.21 cm/s cross flow circulation velocity. The physical and chemical properties of the produced biodiesel were determined and compared with the standard specifications. High quality palm oil biodiesel was produced by combination of heterogeneous alkali transesterification and separation processes in the packed bed membrane reactor.     

Ethanol-induced impairment of polyamine homeostasis – A potential cause of neural tube defect and intrauterine growth restriction in fetal alcohol syndrome

Introduction

Polyamines play a fundamental role during embryogenesis by regulating cell growth and proliferation and by interacting with RNA, DNA and protein. The polyamine pools are regulated by metabolism and uptake from exogenous sources. The use of certain inhibitors of polyamine synthesis causes similar defects to those seen in alcohol exposure e.g. retarded embryo growth and endothelial cell sprouting.

Methods

CD-1 mice received two intraperitoneal injections of 3 g/kg ethanol at 4 h intervals 8.75 days post coitum (dpc). The fetal head, trunk, yolk sac and placenta were collected at 9.5 and 12.5 dpc and polyamine concentrations were determined.

Results

No measurable quantity of polyamines could be detected in the embryo head at 9.5 dpc, 12 h after ethanol exposure. Putrescine was not detectable in the trunk of the embryo at that time, whereas polyamines in yolk sac and placenta were at control level. Polyamine deficiency was associated with slow cell growth, reduction in endothelial cell sprouting, an altered pattern of blood vessel network formation and consequently retarded migration of neural crest cells and growth restriction.

Discussion

Our results indicate that the polyamine pools in embryonic and extraembryonic tissues are developmentally regulated. Alcohol administration, at the critical stage, perturbs polyamine levels with various patterns, depending on the tissue and its developmental stage. The total absence of polyamines in the embryo head at 9.5 dpc may explain why this stage is so vulnerable to the development of neural tube defect, and growth restriction, the findings previously observed in fetal alcohol syndrome.     

In Silico Design of a Poly-epitope Vaccine for Urinary Tract Infection Based on Conserved Antigens by Modern Vaccinology

International Journal of Peptide Research and Therapeutics - Immunoinformatics or vaccine informatics focuses on applying computational approaches to advance vaccine research and development...     

Overexpression of a Rice Monosaccharide Transporter Gene (OsMST6) Confers Enhanced Tolerance to Drought and Salinity Stress in Arabidopsis thaliana

Plant Molecular Biology Reporter - Monosaccharide transporter (MSTs) is a large family of integral membrane proteins that plays a crucial role in cell-to-cell and long-distance distribution of...     

An argument for the use of multiple segment stents in curved arteries

Stenting of curved arteries is generally perceived to be more challenging than straight vessels. Conceptually implanting multiple shorter stents rather than a single longer stent into such a curved artery represents a promising concept, but little is known about the impact of such an approach. The objective of this study is to evaluate the effectiveness of using a multiple segment stent rather than a single long stent to dilate a curved artery using the finite element method. A double segment stent (DSS) and a single segment stent (SSS) were modeled. The stents were compared when expanded into a model of a curved artery. The model predicts that the DSS provides higher flexibility, more conformity, and lower recoil in comparison to the SSS. The volume of arterial tissue experiencing high levels of stress due to stent implantation is also reduced for the DSS. It is suggested that a multiple segment stenting system is a potential solution to the problem of higher rates of in-stent restenosis in curved arteries and mechanically challenging environments.     

H1 histones from mammalian testes : The widespread occurrence of H1t

H1t is a testis-specific H1 histone variant recently isolated from the rat [13]. We have now identified H1t in testicular extracts from mice, rabbits, hamsters, bulls, and boars, thus establishing its widespread presence in animals. H1t from all species could be differentiated from standard somatic H1 forms by a variety of criteria. It was poorly extracted by 5% trichloroacetic acid (TCA), migrated more rapidly than standard H1 forms during electrophoresis in the presence of sodium dodecyl sulfate (SDS), and eluted more slowly than standard H1 species during chromatography over cross-linked polyacrylamide beads (Bio-Gel P100). Using an improved purification procedure, H1t was isolated from two new species, mouse and rabbit. In these species as with the rat, H1t is readily identified by its low lysine (ca 19 mol%) and high arginine (6–7 mol%) content as compared with that of standard somatic H1 forms (ca 25% lysine and 3% arginine).