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

A Comparison of Adolescents\u27 Digital and Print Reading Experiences: Does Mode Matter?

The purpose of this mixed-methods research study was to investigate the comprehension and motivation of 36, sixth-grade students reading moderately challenging text under two conditions: Nook or book. Using a Sequential Explanatory Design model, quantitative data were collected prior to qualitative data collection (Creswell & Plano Clark, 2011). A Matched Pairs Design model (Hinkle, Wiersma, & Jurs, 2003) was employed for the quantitative portion of the study with 18 participants randomly assigned to the Nook group and 18 participants randomly assigned to the book group. Nook group participants were instructed to use the following electronic features during reading: highlighting, note taking, and dictionary usage. The book group participants received instruction for using actual highlighters, sticky notes, and dictionaries during reading. Participants read and responded to Sounder (Armstrong, 1969) in either a traditional or digital (Nook) format. Quantitative data included scores on a reading motivation survey and summative comprehension test. Qualitative data included students’ journal entries, researcher’s field notes, and participants’ verbal responses to interview questions. Results indicate the Nook group achieved higher overall comprehension scores with statistically significant higher inferential comprehension scores than the book group. Nook group participants also read approximately 3 minutes longer per day, chose a free-write response option (as opposed to responding to researcher-constructed writing prompts), and cited text more frequently in journal responses than book group participants. Findings suggest that engaging students in reading digital text and teaching them to use the technology’s facilitative features has the potential to improve student’s reading comprehension of moderately challenging text

Football and Family: The Influence of Family on Team Support Among Dundee United Fans

Heather Andrews explores the relationship between family and football team support in Dundee

Comparison of Recycling Outcomes in Three Types of Recycling Collection Units

Commercial institutions have many factors to consider when implementing an effective recycling program. This study examined the effectiveness of three different types of recycling bins on recycling accuracy by determining the percent weight of recyclable material placed in the recycling bins, comparing the percent weight of recyclable material by type of container used, and examining whether a change in signage increased recycling accuracy. Data were collected over 6 weeks totaling 30 days from 3 different recycling bin types at a Midwest university medical center. Five bin locations for each bin type were used. Bags from these bins were collected, sorted into recyclable and nonrecyclable material, and weighed. The percent recyclable material was calculated using these weights. Common contaminates found in the bins were napkins and paper towels, plastic food wrapping, plastic bags, and coffee cups. The results showed a significant difference in percent recyclable material between bin types and bin locations. Bin type 2 was found to have one bin location to be statistically different (p = 0.048), which may have been due to lack of a trash bin next to the recycling bin in that location. Bin type 3 had significantly lower percent recyclable material (p \u3c 0.001), which may have been due to lack of a trash bin next to the recycling bin and increased contamination due to the combination of commingled and paper into one bag. There was no significant change in percent recyclable material in recycling bins post signage change. These results suggest a signage change may not be an effective way, when used alone, to increase recycling compliance and accuracy. This study showed two or three-compartment bins located next to a trash bin may be the best bin type for recycling accuracy

Using a Scaffolded Multi-Component Intervention to Support the Reading and Writing Development of English Learners

Growing numbers of English learners (National Clearinghouse for English Language Acquisition, 2010) suggest the critical need for effective research-based interventions to support them. Interventions that are designed to help English learners make reading-writing connections are more likely to capitalize on the reciprocal nature of both reading and writing (Tierney & Pearson, 1983) and accelerate literacy development (Clay, 1998). Our teacher research investigation suggests that instructional models that strengthen language and literacy processes through scaffolding and mediational approaches such as read-alouds, shared reading and writing, interactive writing, and individual guided writing show promise in supporting the literacy progress of young English learners. In this collaborative practitioner investigation, second-grade English learners received literacy instruction in an ESOL pull-out program two days per week. In six weeks, these learners demonstrated growth in reading levels, phonemic awareness, and orthographic awareness as indicated in pre- and post-test assessments. The findings suggest long-range investigation of this intervention model is warranted