Phosphorylation of Eukaryotic Initiation Factor-2 Alpha in Response to Endoplasmic Reticulum Stress and Nitrosative Stress in the Protozoan Parasite, \u3ci\u3eEntamoeba histolytica\u3c/i\u3e

Entamoeba histolytica is an intestinal parasite infecting over 50 million people worldwide and is the causative agent of amebic dysentery and amoebic liver abscess. In the human host and nonhuman primates, E. histolytica experiences stress brought on by nutrient deprivation and the host immune response. To be a successful parasite, E. histolytica must counter the stress; therefore, understanding the stress response may uncover new drug targets. In many systems, the stress response includes down-regulation of general protein translation, which is regulated by phosphorylation of eukaryotic initiation factor (eIF-2α). Previous work in E. histolytica has demonstrated that EheIF-2α phosphorylation increases significantly when exposed to long-term serum starvation, oxidative stress, and long-term heat shock. However, the effects of nitrosative and endoplasmic reticulum (ER) stresses, on the eIF2α protein translation control system have yet to be evaluated. Nitrosative stress is part of the host’s immune response and ER stress can be caused by several physiological or pathological factors. We treated E. histolytica cells with different reagents to induce nitrosative stress (DPTA-NONOate and SNP) or ER stress (BFA and DTT). We examined the morphology of the ER, tracked phosphorylation of eIF2α, and assessed protein translation in the control and stressed cells. While all four stress-inducing reagents caused a global reduction in protein translation, only DTT was capable of also inducing changes in the morphology of the ER (consistent with ER stress) and phosphorylation of EheIF-2α. This suggests that DTT authentically induces ER stress in E. histolytica and that this stress is managed by the eIF2α-based system. This was supported by the observation that cells expressing a non-phosphorylatable version of eIF2α were also highly sensitive to DTT-stress. Since protein translation decreased in the absence of phosphorylation of eIF2α (after treatment with DPTA-NONOate, SNP or BFA), the data also indicate that there are alternative protein-translational control pathways in E. histolytica. Overall, our study further illuminates the nitrosative and ER stress responses in E. histolytica

Characterization of Kinases and Hypothetical Proteins in the Entamoeba Species

Entamoeba histolytica is a protozoan parasite that causes amebic dysentery and amoebic liver abscess. This pathogen possesses a two-stage life cycle consisting of an environmentally stable latent cyst and a pathogenic amoeboid trophozoite. Since infection is acquired by ingestion of cysts from contaminated food and water, this parasite is prevalent in underdeveloped countries. A reptilian pathogen, Entamoeba invadens, which can encyst in culture, has long-served as a surrogate to study stage conversion. Much remains unclear about stage conversion and the stress response in these parasites and current treatments for amoebiasis are lacking, as they cause severe side effects. Ultimately new therapeutic strategies are needed and the parasite stress response and stage conversion mechanisms may represent targetable vulnerabilities. To gain insight into these cellular processes, we characterized two hypothetical proteins, EIN_059080 (in E. invadens), and EHI_056700 (in E. histolytica). We also characterized two putative eIF2 alpha kinases in E. invadens. In all cases, we used an RNAi-based silencing system to reduce expression of the genes. Reduction of EIN_059080 expression resulted in a decreased rate of encystation and an increased rate of erythrophagocytosis, an important virulence function. Additionally, these mutants were more susceptible to oxidative stress. Similarly, reduction of EHI_056700 resulted in increased susceptibility to oxidative stress and glucose deprivation, but not to nitrosative stress. Interestingly, parasites with decreased expression of EHI_056700 also exhibited decreased erythrophagocytosis and adhesion to host cells. We authenticated the two eIF2α kinases using a heterologous yeast system. Parasites with decreased kinase expression exhibited decreased phosphorylation of eIF2α and increased sensitivity to oxidative stress. Diminished kinase expression also correlated with an increased rate of encystation, a decreased the rate of excystation, and an increase in several virulence functions, erythrophagocytosis and adhesion to host cells. Taken together, these data suggest that these hypothetical proteins and kinases may play a role in various aspects of stage conversion, virulence, and the response to stress

Using an Action Research Approach to Embed Service Design in a Higher Education Institution

Design Thinking can address the political and cultural divides in higher education and improve the focus on student experience. The challenge is reshaping a traditional organisation into a more modern one and at the same time creating an environment that is favourable towards change brought about by design-led thinking. In one higher education institute, almost two years into the journey and despite some challenges along the way, Service Design methods are demonstrating their capacity to change the processes and procedures that support the delivery of student services in higher education. An action research approach is currently being used to assess how the tools of Design Thinking are applied to real organisational problems and the consequences of design-led action. This research introduces a new set of tools and techniques to an organisation and analyses the effects of this fresh approach on the organisation via a number of action research cycles. There are many stages on the road to introduce Design Thinking as a bottom-up approach to changing an organisation into a more innovative, progressive, efficient and user-centred one

Roles for Faculty in Reducing Barriers to Success for Part-Time Graduate Students

There is limited research on the barriers to successful degree completion for part-time graduate students. The purpose of this paper is to present the results of a survey on former part-time graduate students at Penn State Harrisburg and to discuss the influence that faculty and advisors can have on their success in completing graduate degrees

Screening for abdominal aortic aneurysm - a pilot study in six medical schemes

No Abstract

Tools for Using and Organizing Online Resources to Enhance Reference and Instruction

Presentation at the 2010 Utah Library Association annual conference. This presentation addressed different tools that can be used to incorporate technology and online resources into teaching and instruction

Interruptions of antiretroviral therapy in children and adolescents with HIV infection in clinical practice: a retrospective cohort study in the USA.

INTRODUCTION: Changes in combination antiretroviral therapy (cART) throughout childhood challenge the continuity of paediatric HIV treatment. This study aimed to evaluate the prevalence of treatment interruption (TI), including lamivudine (3TC) monotherapy, and the relationship of TI to virologic and immunologic parameters in HIV-infected paediatric patients. METHODS: Nested within a prospective observational study of a city-wide cohort of HIV-infected persons in the District of Columbia, this sub-study collected retrospective data on antiretroviral therapy, enrolment (endpoint) and historic (lifelong) CD4 counts and HIV RNA viral load (VL) of the paediatric cohort. TI was defined as interruption of cART ≥4 consecutive weeks. Data on TI, including 3TC monotherapy TI (MTI), were collected. Descriptive statistics and univariate testing were used to compare children with TI and MTI to children on continuous treatment (CT). RESULTS: Thirty-eight (28%) out of 136 enrolled children (median age=12.9 years) experienced TI, with 14 (37%) of those placed on 3TC MTI. Significantly lower endpoint median CD4 counts (598 cells/mm(3) vs. 815 cells/mm(3); p=0.003) and CD4% (27.5% vs. 33%; p=0.006) were observed in the TI cohort as compared to the CT cohort. The median endpoint VL in the overall TI cohort was ~4 times higher than among the CT cohort (1427 copies/mL vs. 5581 copies/mL; p CONCLUSIONS: In our study, we observed high frequency of the TI in HIV in paediatric HIV clinical practice. All TIs, including 3TC MTI, were associated with significantly lower endpoint median CD4 counts and higher median VLs, as compared to CT in paediatric patients. The high frequency of TI and associated poor outcomes suggest a need for a better strategy in managing the course of the paediatric and adolescent cART

Determinants of National Guard Mental Health Service Utilization in VA versus Non‐VA Settings

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134155/1/hesr12446.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134155/2/hesr12446-sup-0001-AppendixSA1.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134155/3/hesr12446_am.pd

Assistive technology design and development for acceptable robotics companions for ageing years

© 2013 Farshid Amirabdollahian et al., licensee Versita Sp. z o. o. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivs license, which means that the text may be used for non-commercial purposes, provided credit is given to the author.A new stream of research and development responds to changes in life expectancy across the world. It includes technologies which enhance well-being of individuals, specifically for older people. The ACCOMPANY project focuses on home companion technologies and issues surrounding technology development for assistive purposes. The project responds to some overlooked aspects of technology design, divided into multiple areas such as empathic and social human-robot interaction, robot learning and memory visualisation, and monitoring persons’ activities at home. To bring these aspects together, a dedicated task is identified to ensure technological integration of these multiple approaches on an existing robotic platform, Care-O-Bot®3 in the context of a smart-home environment utilising a multitude of sensor arrays. Formative and summative evaluation cycles are then used to assess the emerging prototype towards identifying acceptable behaviours and roles for the robot, for example role as a butler or a trainer, while also comparing user requirements to achieved progress. In a novel approach, the project considers ethical concerns and by highlighting principles such as autonomy, independence, enablement, safety and privacy, it embarks on providing a discussion medium where user views on these principles and the existing tension between some of these principles, for example tension between privacy and autonomy over safety, can be captured and considered in design cycles and throughout project developmentsPeer reviewe