428 research outputs found
A Wide-angle Multi-Octave Broadband Waveplate Based on Field Transformation Approach
J.Z. acknowledge the support from the National Nature Science Foundation of China (61571218, 61571216, 61301017, 61371034, 61101011), and the Ph.D. Programs Foundation of Ministry of Education of China (20120091110032, 20110091120052). Y. H. acknowledge the support from the UK EPSRC under the QUEST Programme Grant (EP/I034548/1)
Expression of a Serine Protease Gene prC Is Up-Regulated by Oxidative Stress in the Fungus Clonostachys rosea: Implications for Fungal Survival
BACKGROUND: Soil fungi face a variety of environmental stresses such as UV light, high temperature, and heavy metals. Adaptation of gene expression through transcriptional regulation is a key mechanism in fungal response to environmental stress. In Saccharomyces cerevisiae, the transcription factors Msn2/4 induce stress-mediated gene expression by binding to the stress response element. Previous studies have demonstrated that the expression of extracellular proteases is up-regulated in response to heat shock in fungi. However, the physiological significance of regulation of these extracellular proteases by heat shock remains unclear. The nematophagous fungus Clonostachys rosea can secret an extracellular serine protease PrC during the infection of nematodes. Since the promoter of prC has three copies of the stress response element, we investigated the effect of environmental stress on the expression of prC. METHODOLOGY/PRINCIPAL FINDINGS: Our results demonstrated that the expression of prC was up-regulated by oxidants (H(2)O(2) or menadione) and heat shock, most likely through the stress response element. After oxidant treatment or heat shock, the germination of conidia in the wild type strain was significantly higher than that in the prC mutant strain in the presence of nematode cuticle. Interestingly, the addition of nematode cuticle significantly attenuated the production of reactive oxygen species (ROS) induced by oxidants and heat shock in the wild type strain, but not in prC mutant strain. Moreover, low molecule weight (<3 kD) degradation products of nematode cuticle suppressed the inhibitory effect of conidial germination induced by oxidants and heat shock. CONCLUSIONS/SIGNIFICANCE: These results indicate that PrC plays a protective role in oxidative stress in C. rosea. PrC degrades the nematode cuticle to produce degradation products, which in turn offer a protective effect against oxidative stress by scavenging ROS. Our study reveals a novel strategy for fungi to adapt to environmental stress
Characterization of a novel PTEN mutation in MDA-MB-453 breast carcinoma cell line
<p>Abstract</p> <p>Background</p> <p>Cowden Syndrome (CS) patients with germ line point mutations in the <it>PTEN </it>gene are at high risk for developing breast cancer. It is believed that cells harboring these mutant <it>PTEN </it>alleles are predisposed to malignant conversion. This article will characterize the biochemical and biological properties of a mutant PTEN protein found in a commonly used metastatic breast cancer cell line.</p> <p>Methods</p> <p>The expression of PTEN in human breast carcinoma cell lines was evaluated by Western blotting analysis. Cell line MDA-MB-453 was selected for further analysis. Mutation analysis of the <it>PTEN </it>gene was carried out using DNA isolated from MDA-MB-453. Site-directed mutagenesis was used to generate a PTEN E307K mutant cDNA and ectopic expressed in PC3, U87MG, MCF7 and <it>Pten</it><sup>-/- </sup>mouse embryo fibroblasts (MEFS). Histidine (His)-tagged PTEN fusion protein was generated in <it>Sf9 </it>baculovirus expression system. Lipid phosphatase and ubiquitination assays were carried out to characterize the biochemical properties of PTEN E307K mutant. The intracellular localization of PTEN E307K was determined by subcellular fractionation experiments. The ability of PTEN E307K to alter cell growth, migration and apoptosis was analyzed in multiple PTEN-null cell lines.</p> <p>Results</p> <p>We found a mutation in the <it>PTEN </it>gene at codon 307 in MDA-MB-453 cell line. The glutamate (E) to lysine (K) substitution rendered the mutant protein to migrate with a faster mobility on SDS-PAGE gels. Biochemically, the PTEN E307K mutant displayed similar lipid phosphatase and growth suppressing activities when compared to wild-type (WT) protein. However, the PTEN E307K mutant was present at higher levels in the membrane fraction and suppressed Akt activation to a greater extent than the WT protein. Additionally, the PTEN E307K mutant was polyubiquitinated to a greater extent by NEDD4-1 and displayed reduced nuclear localization. Finally, the PTEN E307K mutant failed to confer chemosensitivity to cisplatinum when re-expressed in <it>Pten</it><sup>-/- </sup>MEFS.</p> <p>Conclusions</p> <p>Mutation at codon 307 in PTEN C2 loop alters its subcellular distribution with greater membrane localization while being excluded from the cell nucleus. This mutation may predispose breast epithelial cells to malignant transformation. Also, tumor cells harboring this mutation may be less susceptible to the cytotoxic effects of chemotherapeutics.</p
Recommended from our members
Methane emission by Camelids
Methane emissions from ruminant livestock have been intensively studied in order to reduce contribution to the greenhouse effect. Ruminants were found to produce more enteric methane than other mammalian herbivores. As camelids share some features of their digestive anatomy and physiology with ruminants, it has been proposed that they produce similar amounts of methane per unit of body mass. This is of special relevance for countrywide greenhouse gas budgets of countries that harbor large populations of camelids like Australia. However, hardly any quantitative methane emission measurements have been performed in camelids. In order to fill this gap, we carried out respiration chamber measurements with three camelid species (Vicugna pacos, Lama glama, Camelus bactrianus; n = 16 in total), all kept on a diet consisting of food produced from alfalfa only. The camelids produced less methane expressed on the basis of body mass (0.3260.11 L kg21 d21) when compared to literature data on domestic ruminants fed on roughage diets (0.5860.16 L kg21 d21). However, there was no significant difference between the two suborders when methane emission was expressed on the basis of digestible neutral detergent fiber intake (92.7633.9 L kg21 in camelids vs. 86.2612.1 L kg21 in ruminants). This implies that the pathways of methanogenesis forming part of the microbial digestion of fiber in the foregut are similar between the groups, and that the lower methane emission of camelids can be explained by their generally lower relative food intake. Our results suggest that the methane emission of Australia’s feral camels corresponds only to 1 to 2% of the methane amount produced by the countries’ domestic ruminants and that calculations of greenhouse gas budgets of countries with large camelid populations based on equations developed for ruminants are generally overestimating the actual levels
Patient-reported outcome measures of the impact of cancer on patient’s everyday lives: a systematic review
Purpose: Patients with advanced disease are living longer and commonly used patient-reported outcome measures (PROMs) may miss relevant elements of the quality of extended survival. This systematic review examines the measures used to capture aspects of the quality of survival including impact on patients’ everyday lives such as finances, work and family roles.
Methods: Searches were conducted in MEDLINE, EMBASE,
CINAHL and PsycINFO restricted to English language articles. Information on study characteristics, instruments and outcomes was systematically extracted and synthesised. A predefined set of criteria was used to rate the quality of studies.
Results: From 2761 potentially relevant articles, 22 met all inclusion criteria, including 10 concerning financial distress, 3 on roles and responsibilities and 9 on multiple aspects of social well-being. Generally, studies were not of high quality; many lacked bias free participant selection, had confounding factors and had not accounted for all participants. High levels of financial distress were reported and were associated with multiple demographic factors such as age and income. There were few reports concerned with impacts on patients’ roles/responsibilities in everyday life although practical and emotional struggles with parenting were identified. Social difficulties were common and associated with multiple factors including being a caregiver. Many studies were single time-point surveys and used non-validated measures. Exceptions were employment of the COST and Social Difficulties Inventory (SDI), validated measures of financial and social distress respectively.
Conclusions: Impact on some important parts of patients’ everyday lives is insufficiently and inconsistently captured. Further PROM development focussing on roles and responsibilities, including work and caring for dependents, is warranted.
Implications for Cancer Survivors: Factors such as finances, employment and responsibility for caring for dependents (e.g. children and elderly relatives) can affect the well-being of cancer survivors. There is a need to ensure that any instruments used to assess patients’ social well-being are broad enough to include these areas so that any difficulties arising can be better understood and appropriately supported
The effect on work presenteeism of job retention vocational rehabilitation compared to a written self-help work advice pack for employed people with inflammatory arthritis: protocol for a multi-centre randomised controlled trial (the WORKWELL trial)
Abstract: Background: Work problems are common in people with inflammatory arthritis. Up to 50% stop work within 10 years due to their condition and up to 67% report presenteeism (i.e. reduced work productivity), even amongst those with low disease activity. Job retention vocational rehabilitation (JRVR) may help prevent or postpone job loss and reduce presenteeism through work assessment, work-related rehabilitation and enabling job accommodations. This aims to create a better match between the person’s abilities and their job demands. The objectives of the Workwell trial are to test the overall effectiveness and cost-effectiveness of JRVR (WORKWELL) provided by additionally trained National Health Service (NHS) occupational therapists compared to a control group who receive self-help information both in addition to usual care. Methods: Based on the learning from a feasibility trial (the WORK-IA trial: ISRCTN76777720), the WORKWELL trial is a multi-centre, pragmatic, individually-randomised parallel group superiority trial, including economic evaluation, contextual factors analysis and process evaluation. Two hundred forty employed adults with rheumatoid arthritis, undifferentiated inflammatory arthritis or psoriatic arthritis (in secondary care), aged 18 years or older with work instability will be randomised to one of two groups: a self-help written work advice pack plus usual care (control intervention); or WORKWELL JRVR plus a self-help written work advice pack and usual care. WORKWELL will be delivered by occupational therapists provided with additional JRVR training from the research team. The primary outcome is presenteeism as measured using the Work Limitations Questionnaire-25. A comprehensive range of secondary outcomes of work, health, contextual factors and health resource use are included. Outcomes are measured at 6- and 12- months (with 12-months as the primary end-point). A multi-perspective within-trial cost-effectiveness analyses will also be conducted. Discussion: This trial will contribute to the evidence base for provision of JRVR to people with inflammatory arthritis. If JRVR is found to be effective in enabling people to keep working, the findings will support decision-making about provision of JRVR by rheumatology teams, therapy services and healthcare commissioners, and providing evidence of the effectiveness of JRVR and the economic impact of its implementation. Trial registration: Clinical Trials.Gov: NCT03942783. Registered 08/05/2019 (https://clinicaltrials.gov/ct2/show/NCT03942783); ISRCTN Registry: ISRCTN61762297. Registered:13/05/2019 (http://www.isrctn.com/ISRCTN61762297). Retrospectively registered
Breast cancer metastasis to the bone: mechanisms of bone loss
Breast cancer frequently metastasizes to the skeleton, interrupting the normal bone remodeling process and causing bone degradation. Osteolytic lesions are the end result of osteoclast activity; however, osteoclast differentiation and activation are mediated by osteoblast production of RANKL (receptor activator for NFÎşB ligand) and several osteoclastogenic cytokines. Osteoblasts themselves are negatively affected by cancer cells as evidenced by an increase in apoptosis and a decrease in proteins required for new bone formation. Thus, bone loss is due to both increased activation of osteoclasts and suppression of osteoblasts. This review summarizes the current understanding of the osteolytic mechanisms of bone metastases, including a discussion of current therapies
The Cis-regulatory Logic of the Mammalian Photoreceptor Transcriptional Network
The photoreceptor cells of the retina are subject to a greater number of genetic diseases than any other cell type in the human body. The majority of more than 120 cloned human blindness genes are highly expressed in photoreceptors. In order to establish an integrative framework in which to understand these diseases, we have undertaken an experimental and computational analysis of the network controlled by the mammalian photoreceptor transcription factors, Crx, Nrl, and Nr2e3. Using microarray and in situ hybridization datasets we have produced a model of this network which contains over 600 genes, including numerous retinal disease loci as well as previously uncharacterized photoreceptor transcription factors. To elucidate the connectivity of this network, we devised a computational algorithm to identify the photoreceptor-specific cis-regulatory elements (CREs) mediating the interactions between these transcription factors and their target genes. In vivo validation of our computational predictions resulted in the discovery of 19 novel photoreceptor-specific CREs near retinal disease genes. Examination of these CREs permitted the definition of a simple cis-regulatory grammar rule associated with high-level expression. To test the generality of this rule, we used an expanded form of it as a selection filter to evolve photoreceptor CREs from random DNA sequences in silico. When fused to fluorescent reporters, these evolved CREs drove strong, photoreceptor-specific expression in vivo. This study represents the first systematic identification and in vivo validation of CREs in a mammalian neuronal cell type and lays the groundwork for a systems biology of photoreceptor transcriptional regulation
- …