In this study, we measured the levels of elements in human brain microvascular endothelial cells (ECs) infected with T. gondii. ECs were infected with tachyzoites of the RH strain, and at 6, 24, and 48 hours post infection (hpi), the intracellular concentrations of elements were determined using a synchrotron-microfocus X-ray fluorescence microscopy (μ-XRF) system. This method enabled the quantification of the concentrations of Zn and Ca in infected and uninfected (control) ECs at sub-micron spatial resolution. T. gondii-hosting ECs contained less Zn than uninfected cells only at 48 hpi (p < 0.01). The level of Ca was not significantly different between infected and control cells (p > 0.05). Inductively Coupled Plasma Mass Spectrometry (ICP-MS) analysis revealed infection-specific metallome profiles characterized by significant increases in the intracellular levels of Zn, Fe, Mn and Cu at 48 hpi (p < 0.01), and significant reductions in the extracellular concentrations of Co, Cu, Mo, V, and Ag at 24 hpi (p < 0.05) compared with control cells. Zn constituted the largest part (74%) of the total metal composition (metallome) of the parasite. Gene expression analysis showed infection-specific upregulation in the expression of five genes, MT1JP, MT1M, MT1E, MT1F, and MT1X, belonging to the metallothionein gene family. These results point to a possible correlation between T. gondii infection and increased expression of MT1 isoforms and altered intracellular levels of elements, especially Zn and Fe. Taken together, a combined μ-XRF and ICP-MS approach is promising for studies of the role of elements in mediating host-parasite interaction.

Label-free chemical profiling identifies macromolecules significantly associated with Toxoplasma gondii infection in cerebrovascular endothelial cells.

At the University of Nottingham peer-assessment was piloted with the objective of assisting students to gain greater understanding of marking criteria so that students may improve their comprehension of, and solutions to, future mathematical tasks. The study resulted in improvement in all four factors of observation, emulation, self-control and self-regulation thus providing evidence of a positive impact on student learning.The pilot involved a large first-year mathematics class who completed a formative piece of coursework prior to a problem class. At the problem class students were trained in the use of marking criteria before anonymously marking peer work. The pilot was evaluated using questionnaires (97 responses) at the beginning and end of the problem class. The questionnaires elicited students’ understanding of criteria before and after the task and students’ self-efficacy in relation to assessment self-control and self-regulation.The analysis of students’ descriptions of the criteria of assessment show that their understanding of the requirements for the task were expanded. After the class, explanation of the method and notation (consistent and correct) were much more present in students’ descriptions. Furthermore, 67 per cent of students stated they had specific ideas on how to improve their solutions to problems in the future. Students’ self-perceived abilities to self-assess and improve were positively impacted. The pilot gives strong evidence for the use of peer-assessment to develop students’ competencies as assessors, both in terms of their understanding of marking criteria and more broadly their ability to self-assess and regulate their learning.