•The effect of window views on attention and stress were tested using randomized controlled experiment.•Window views to green landscapes promote high school students’ attention restoration.•Window ...views to green landscapes speed high school students’ recover from stress.•Attention restoration and stress recovery are separate pathways.•Exposure to daylight alone did not improve student performance.
Previous research has demonstrated positive associations between the greenness of high school landscapes and school wide academic performance. We do not known, however, if green landscapes cause better performance or if the association between the two is a product of self-selection. If there is a causal relationship, the pathways through which green school landscapes affect student performance remain unclear. We hypothesize that views onto green landscapes help students recover from mental fatigue and stress. To test these hypotheses, we conducted a randomized controlled experiment with 94 high school students at five high schools. Participants were randomly assigned to classrooms without windows or with windows that opened onto a built space or a green space. Participants engaged in typical classroom activities followed by a break in the classroom to which they were assigned. Attentional functioning was measured using Digit Span Forward and Backwards. Physiological stress levels were measured by skin conductance, body temperature, pNN50 (the proportion of the number of pairs of successive NNs that differ by more than 50ms divided by the total number of NNs) and LF/HF (the ratio between low-frequency peak and high frequency peak). Results demonstrate that classroom views to green landscapes cause significantly better performance on tests of attention and increase student's recovery from stressful experiences. A lack of mediation effect demonstrates that attention restoration and stress recovery are two distinct processes. Implications for school site selection, design and renovation are discussed.
Students and their parents wonder if college is worth the investment. Employers want graduates with the skills they need. The public wonders if higher education is preparing future generations for an ...era of dynamic change. In his latest book, William Sullivan offers a model of higher education that answers all these questions in the affirmative, through the power of integrated learning. Drawing on examples from the 25 members of the New American Colleges & Universities (NAC&U) consortium, the book makes the case for an approach that combines the strengths of the liberal arts, professional studies, and civic responsibility in order to give students the combination of skills and experience that will prepare them for success in all aspects of life after graduation.NAC&U campuses place emphasis upon enabling their students to know themselves and their abilities, as well as providing them with opportunities to develop a sophisticated understanding of the world. To achieve these goals, the academic programs focus on developing students' intellectual and practical skills, such as analytical ability, problem solving, facility in written and spoken communication, and an appreciation for human diversity and creativity. These have traditionally been identified as the goals of a liberal arts education, and are the same ones identified in a national employer survey as giving job-seekers an edge.These institutions also invest a great deal of effort to provide their students with state-of-the-art preparation for professional life and occupational success in diverse fields. These range from the technical - science and technology fields, with disciplines such as engineering and computer science - through business, and across the human service fields, such as education, nursing, pre-medicine, and pre-law, to architecture, and the performing and visual arts. In these courses of study, students begin to shape their future careers.The important third value of a NAC&U education is fos
A critical factor in the transmission and pathogenesis of
Toxoplasma gondii
is the ability to convert from an acute disease-causing, proliferative stage (tachyzoite), to a chronic, dormant stage ...(bradyzoite). The conversion of the tachyzoite-containing parasitophorous vacuole membrane into the less permeable bradyzoite cyst wall allows the parasite to persist for years within the host to maximize transmissibility to both primary (felids) and secondary (virtually all other warm-blooded vertebrates) hosts. This review presents our current understanding of the latent stage, including the factors that are important in bradyzoite induction and maintenance. Also discussed are the recent studies that have begun to unravel the mechanisms behind stage switching.
Tachyzoite to bradyzoite development in Toxoplasma is marked by major changes in gene expression resulting in a parasite that expresses a new repertoire of surface antigens hidden inside a modified ...parasitophorous vacuole called the tissue cyst. The factors that control this important life cycle transition are not well understood. Here we describe an important transcriptional repressor mechanism controlling bradyzoite differentiation that operates in the tachyzoite stage. The ApiAP2 factor, AP2IV-4, is a nuclear factor dynamically expressed in late S phase through mitosis/cytokinesis of the tachyzoite cell cycle. Remarkably, deletion of the AP2IV-4 locus resulted in the expression of a subset of bradyzoite-specific proteins in replicating tachyzoites that included tissue cyst wall components BPK1, MCP4, CST1 and the surface antigen SRS9. In the murine animal model, the mis-timing of bradyzoite antigens in tachyzoites lacking AP2IV-4 caused a potent inflammatory monocyte immune response that effectively eliminated this parasite and prevented tissue cyst formation in mouse brain tissue. Altogether, these results indicate that suppression of bradyzoite antigens by AP2IV-4 during acute infection is required for Toxoplasma to successfully establish a chronic infection in the immune-competent host.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
While histone proteins are the founding members of lysine acetylation substrates, it is now clear that hundreds of other proteins can be acetylated in multiple compartments of the cell. Our knowledge ...of the scope of this modification throughout the kingdom of life is beginning to emerge, as proteome-wide lysine acetylation has been documented in prokaryotes, Arabidopsis thaliana, Drosophila melanogaster, and human cells. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify parasite peptides enriched by immunopurification with acetyl-lysine antibody, we produced the first proteome-wide analysis of acetylation for a protozoan organism, the opportunistic apicomplexan parasite Toxoplasma gondii. The results show that lysine acetylation is abundant in the actively proliferating tachyzoite form of the parasite, which causes acute toxoplasmosis. Our approach successfully identified known acetylation marks on Toxoplasma histones and α-tubulin and detected over 400 novel acetylation sites on a wide variety of additional proteins, including those with roles in transcription, translation, metabolism, and stress responses. Importantly, an extensive set of parasite-specific proteins, including those found in organelles unique to Apicomplexa, is acetylated in the parasite. Our data provide a wealth of new information that improves our understanding of the evolution of this vital regulatory modification while potentially revealing novel therapeutic avenues. We conclude from this study that lysine acetylation was prevalent in the early stages of eukaryotic cell evolution and occurs on proteins involved in a remarkably diverse array of cellular functions, including those that are specific to parasites.
•We describe the dose–response curve for the impact of tree cover density on stress reduction.•We employed 6-min, 3-D videos of community street scenes as the nature treatment.•We measured skin ...conductance and salivary cortisol levels as measures of participants’ stress.•For men, the dose–response curve was an inverted-U shape.•For women, we found no relationship between tree cover density and stress reduction.
Although it is well established that exposure to nearby nature can help reduce stress in individuals, the shape of the dose–response curve is entirely unclear. To establish this dose–response curve, we recruited 160 individuals for a laboratory experiment. Participants engaged in the Trier Social Stress Test (TSST) to induce psychological stress, and were then randomly assigned to view one of ten, 6-min, 3-D videos of neighborhood streets. The density of tree cover in the videos varied from 1.7% to 62.0%. We measured their stress reactions by assessing salivary cortisol and skin conductance levels. Results show a clear disparity between women and men. For women, we found no relationship between varying densities of tree cover and stress recovery. For men, the dose–response curve was an inverted-U shape: as tree cover density increased from 1.7% to 24%, stress recovery increased. Tree density between 24% to 34% resulted in no change in stress recovery. Tree densities above 34% were associated with slower recovery times. A quadratic regression using tree cover density as the independent variable and a summary stress index as the dependent variable substantiated these results R2=.22, F (2, 68)=9.70, p<.001. The implications for our understanding of the impacts of nearby nature, and for the practice of planning and landscape architecture are discussed.
Abstract
Toxoplasma gondii is an obligate intracellular protozoan parasite that causes opportunistic disease, particularly in immunocompromised individuals. Central to its transmission and ...pathogenesis is the ability of the proliferative stage (tachyzoite) to convert into latent tissue cysts (bradyzoites). Encystment allows Toxoplasma to persist in the host and affords the parasite a unique opportunity to spread to new hosts without proceeding through its sexual stage, which is restricted to felids. Bradyzoite tissue cysts can cause reactivated toxoplasmosis if host immunity becomes impaired. A greater understanding of the molecular mechanisms orchestrating bradyzoite development is needed to better manage the disease. Here, we will review key studies that have contributed to our knowledge about this persistent form of the parasite and how to study it, with a focus on how cellular stress can signal for the reprogramming of gene expression needed during bradyzoite development.
This review describes the molecular mechanisms orchestrating the development of latent tissue cysts of the protozoan parasite Toxoplasma gondii, a process that is critical to pathogenesis and transmission.
Toxoplasma gondii is a prevalent protozoan parasite that can infect any nucleated cell but cannot replicate outside of its host cell. Toxoplasma is auxotrophic for several nutrients including ...arginine, tryptophan, and purines, which it must acquire from its host cell. The demands of parasite replication rapidly deplete the host cell of these essential nutrients, yet Toxoplasma successfully manages to proliferate until it lyses the host cell. In eukaryotic cells, nutrient starvation can induce the integrated stress response (ISR) through phosphorylation of an essential translation factor eIF2. Phosphorylation of eIF2 lowers global protein synthesis coincident with preferential translation of gene transcripts involved in stress adaptation, such as that encoding the transcription factor ATF4 (CREB2), which activates genes that modulate amino acid metabolism and uptake. Here, we discovered that the ISR is induced in host cells infected with Toxoplasma. Our results show that as Toxoplasma depletes host cell arginine, the host cell phosphorylates eIF2 via protein kinase GCN2 (EIF2AK4), leading to induced ATF4. Increased ATF4 then enhances expression of the cationic amino acid transporter CAT1 (SLC7A1), resulting in increased uptake of arginine in Toxoplasma-infected cells. Deletion of host GCN2, or its downstream effectors ATF4 and CAT1, lowers arginine levels in the host, impairing proliferation of the parasite. Our findings establish that Toxoplasma usurps the host cell ISR to help secure nutrients that it needs for parasite replication.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Parasitic infections remain one of the most pressing global health concerns of our day, affecting billions of people and producing unsustainable economic burdens. The rise of drug-resistant parasites ...has created an urgent need to study their biology in hopes of uncovering new potential drug targets. It has been established that disrupting gene expression by interfering with lysine acetylation is detrimental to survival of apicomplexan (Toxoplasma gondii and Plasmodium spp.) and kinetoplastid (Leishmania spp. and Trypanosoma spp.) parasites. As "readers" of lysine acetylation, bromodomain proteins have emerged as key gene expression regulators and a promising new class of drug target. Here we review recent studies that demonstrate the essential roles played by bromodomain-containing proteins in parasite viability, invasion, and stage switching and present work showing the efficacy of bromodomain inhibitors as novel antiparasitic agents. In addition, we performed a phylogenetic analysis of bromodomain proteins in representative pathogens, some of which possess unique features that may be specific to parasite processes and useful in future drug development.
Overuse of portable electronic devices depletes one’s attention capacity, a critical cognitive resource. Although contact with nature promotes attentional functioning, we do not know the extent to ...which exposure to nature and the use of electronic devices interact to promote or inhibit attentional functioning. In this study, 81 participants performed cognitive tasks and then were randomly assigned to one of four rest treatments: green settings with or without a laptop computer and barren settings with or without a laptop computer. Attention was measured three times. Analysis showed a significant effect for both setting and use of a laptop as well as a significant interaction between setting and laptop use. A further analysis controlling for time spent focused on the laptop screen produced similar results. The findings show that using an electronic device in green settings substantially counteracts the attention enhancement benefits of green spaces.
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