Toxoplasma MIC2 Is a Major Determinant of Invasion and Virulence

Like its apicomplexan kin, the obligate intracellular protozoan Toxoplasma gondii actively invades mammalian cells and uses a unique form of gliding motility. The recent identification of several transmembrane adhesive complexes, potentially capable of gripping external receptors and the sub-membrane actinomyosin motor, suggests that the parasite has multiple options for host-cell recognition and invasion. To test whether the transmembrane adhesin MIC2, together with its partner protein M2AP, participates in a major invasion pathway, we utilized a conditional expression system to introduce an anhydrotetracycline-responsive mic2 construct, allowing us to then knockout the endogenous mic2 gene. Conditional suppression of MIC2 provided the first opportunity to directly determine the role of this protein in infection. Reduced MIC2 expression resulted in mistrafficking of M2AP, markedly defective host-cell attachment and invasion, the loss of helical gliding motility, and the inability to support lethal infection in a murine model of acute toxoplasmosis. Survival of mice infected with MIC2-deficient parasites correlated with lower parasite burden in infected tissues, an attenuated inflammatory immune response, and induction of long-term protective immunity. Our findings demonstrate that the MIC2 protein complex is a major virulence determinant for Toxoplasma infection and that MIC2-deficient parasites constitute an effective live-attenuated vaccine for experimental toxoplasmosis

２つの異型ヒストンTH2AとTH2BはヒトiPS細胞の作製を促進する

筑波大学 (University of Tsukuba)201

EFFECTS OF TASK BASED SPEAKING ACTIVITIES ON EFL LEARNERS’ ORAL PERFORMANCE

Task-based speaking activities have attracted considerable attention of many researchers in teaching and learning speaking skills. The current study is aimed at investigating the effects of Task-based speaking activities on non-English major students’ and examining their attitude towards the implication of speaking activities based on tasks. The study was conducted at a university in the Mekong Delta of Vietnam in the second semester of the school year 2020-2021. Fifty-eight non-English major students who are all studying the second course of the General English subject at the university were recruited as participants of the study. A pre-test and post-test were used to measure the participants’ oral performance and a questionnaire was employed to examine the experimental group’s attitude towards the use of task-based speaking activities. The findings indicate that EFL students in the experimental group gained more development in oral performance than their peers in the control group which was instructed in the traditional method. Furthermore, EFL students not only express their completed agreement on the benefits which they receive from speaking lessons practiced with task-based speaking activities. Article visualizations

Impact des métaux lourds sur les interactions plante/ver de terre/microflore tellurique

The objective of this work was to study the interactions between phytoremediating plant Lantana camara (Verbenaceae), the earthworm Pontoscolex corethrurus (Glossocolecidae) and microorganisms in soil contaminated with lead. Initially, it appears that in the contaminated soil, the presence of earthworm leads to an increase in the biomass of root and aerial parts of plants and increased absorption of lead. The physico-chemical characterization of root-aggregates showed that the activity of earthworms increases the rate of organic matter, cation exchange capacity, total nitrogen, total and available potassium. Moreover, the presence of earthworms increases certain enzymatic activities in the rhizosphere. The increased growth of L. camara could result from these different actions. The action of earthworm on plants would be through terrestrial microbial-communities. Thus, the biomass of microorganisms, bacteria and fungi, of root-aggregates increase in the presence of earthworms. By PCR-DGGE, we were unable to demonstrate differences in taxonomic diversity of the bacteria community but the analysis of physiological profiles with Biolog plates showed that the activities of earthworm enhance the functional diversity of soil bacteria. In other hand, the restructuring of fungal taxonomy has been clearly observed by the activity of earthworm. All changes observed can explain increased growth of plants and improved phytoextraction of heavy metal. Finally, the study underlines the role of the earthworms on the growth and the phytoextraction efficiency of the plants. So, the combination of earthworm P. corethrurus and plant L. camara could be considerable potential for the treatment of industrial sites polluted with leadL'objectif de ce travail était d'étudier les interactions entre une plante « phytoremédiatrice », Lantana camara (Verbenaceae), le ver de terre, Pontoscolex corethrurus (Glossoscolecidae) et les microorganismes telluriques d'un sol pollué au plomb. Dans un premier temps, il apparaît que dans les sols contaminés, la présence de ver conduit à un accroissement de la biomasse des parties aériennes et racinaires des plantes ainsi qu'à une augmentation de l'absorption de plomb. La caractérisation physico-chimique des agrégats racinaires a montré que l'activité des vers augmente le taux de matière organique, la capacité d'échange cationique ainsi que l'azote total, le potassium total et disponible. De plus, la présence des vers augmente certaines activités enzymatiques de la rhizosphère. La croissance accrue de L. camara pourrait résulter de ces différentes actions. L'action des vers de terre sur les plantes se ferait via les communautés microbiennes telluriques. Ainsi, la biomasse des microorganismes, bactéries et champignons, des agrégats racinaires augmente en présence de vers. La PCR-DGGE n'a pas permis de mettre en évidence de modifications de la structure taxonomique des communautés bactériennes sous l'influence du Pb et/ou du vers, par contre l'analyse des profils physiologiques par plaques Biolog montre clairement une diversification fonctionnelle bactérienne. Les communautés fongiques voient, elles, leur diversité taxonomique, augmenter sous l'action des vers. La restructuration des populations microbiennes, en présence de vers, des agrégats racinaires élaborés par les plantes en milieu pollué au plomb est l'élément déterminant pour la compréhension de l'impact de P. corethrurus sur la croissance et la phytoremédiation de L. camara. L'association de ces deux organismes aurait donc un potentiel considérable pour le traitement de sites industriels pollués au plom

SYNTHESIS AND APPLICATION OF GRAPHENE/SILVER NANOWIRES/GOLD NANOPARTICLES HYBRID FOR AMMONIA GAS SENSING

Graphene material synthesized from chemical method (reduced Graphene Oxide – rGO) is a promising candidate for gas sensors due to their unique properties. With structure of single layer of bonded sp2 carbons in a two-dimensional (2D) lattice, rGO have large surface to volume ratio, high conductivity and electron mobility at room temperature. Meanwhile, the different oxygen-containing functional groups (contain dangling bonds) decorated on carbon networks make rGO easily respond with compatible gas molecules. However, the investigating of structure of rGO in micrometer scale shows that the chemical method often results in non-uniform film thickness on substrate due to overlap of rGO sheets. These may disrupt the conductive paths in rGO films and decrease their conductivity. Therefore, gas sensing signal of pristine rGO based sensors is tarnished and the sensors do not recover to their baseline at room temperature. In this study, silver nanowires (AgNWs) and gold nanoparticles (AuNPs) are combined with rGO material to form rGO/AgNWs/AuNPs hybrid. With one-dimensional nanostructure, the AgNWs connects effectively together many rGO islands and reduce significantly their contact resistance so that NH3 sensing signal is improved and complete recovery of the sensor is nearly achieved at room temperature. Especially, all these signals are further enhanced when the AuNPs (diameter ~ 30 nm) are added into the hybrid

Frivillighetsturisme: En kartlegging av motivasjonsfaktorer

I denne oppgaven har vi sett nærmere på fenomenet frivillighetsturisme. Fenomenet er lite forsket på i Norge, men likevel er det kjent blant nordmenn ettersom stadig flere velger å kombinere reising med frivillig arbeid. Basert på vår interesse for frivillighetsturisme har denne oppgaven som formål å se nærmere på motivasjonsfaktorer som ligger til grunn for å kombinere reising og frivillig arbeid. I en tidlig fase brukte vi mye tid på litteraturgjennomgang som ga oss god innsikt i temaet, og basert på arbeidet med prosjektskisse 2 kom vi frem til følgende problemstilling: “Hvilke motivasjonsfaktorer ligger til grunn ved valg av frivillig arbeid i utlandet”. For å kunne svare på vår problemstilling utviklet vi tre forskningsspørsmål basert på tre sentrale dimensjoner i henhold til fenomenet, som skulle hjelpe oss med å svare på problemstillingen: 1. Hva kjennetegner opplevelsesdimensjonen ved kombinering av reising og frivillig arbeid? 2. Foreligger det forskjeller på motivasjonsfaktorer blant norske ungdommer og internasjonale funn? 3. Er motivasjonsfaktorene for å arbeide frivillig i utlandet altruistiske, egoistiske eller en kombinasjon? Denne avhandlingen har et fenomenologisk forskningsdesign og vi har benyttet oss av åpne, individuelle intervjuer ved datainnsamlingen. Vi har intervjuet åtte informanter som tidligere har kombinert reising med frivillig arbeid. Med utgangspunkt i forskningsdesignet har vi gjort et detaljert analysearbeid med utgangspunkt i fenomenologisk analyse av meningsinnhold. Basert på analysearbeidet har drøftelsen av funn og resultater tatt utgangspunkt i følgende tre temaer som representer våre tre forskningsspørsmål; opplevelsesdimensjonen, våre funn sammenlignet med internasjonale funn, og forholdet mellom egoisme og altruisme. Forskningsspørsmålene har lagt et solid grunnlag for å kartlegge motivasjonsfaktorer, og vi har på grunnlag av disse funnet følgende sentrale faktorer; selvutvikling, kulturell neddykking, virkelighetsbilde, opplevelse og å hjelpe

An Exploration in Social and Emotional Health of Vietnamese High School Students

Social and emotional health (SEH) aims to promote academic success and create school well-being. SEH has not been studied in Vietnam. This article focused on exploring the SEH of Vietnamese high school students because of the high-risk level in mental health that appeared in this group. The study was carried out using a qualitative case study approach to interviewing 74 students, 12 teachers, 7 school administrators, and 4 school counselors. We interpreted four features of SEH\u27s expression of Vietnamese students: (1) Confident but lack of individual perspectives, (2) Respectful but lack of listening and empathy in school relationships, (3) Balanced but lack of authentic perception of emotions and effective emotional management, (4) Satisfied but lack of sustainability and action. This study has broadened our understanding of external behaviours and current limitations in the young people’s SEH from their perspectives in a developing Southeast Asian country to promote positive psychological development in school-based prevention programs

MOTIVATION TO STUDY ENGLISH OF NON-ENGLISH MAJORED FRESHMEN

Motivation is regarded as an influential factor in the success of any activity. It plays a significant role in reaching the desired goals, including learning English. This research aims to analyze the students' motivation and factors affecting their motivation to learn English. The population of this study was 326 freshmen in nine faculties of natural sciences at Tay Do University. The quantitative data was collected through the questionnaire and analyzed by SPSS software. The results show that the students had motivation to learn English, but their motivation levels were not high. Additionally, the students had both intrinsic and extrinsic motivation. However, the latter was higher than the former. Moreover, the results also indicate factors affecting learners’ motivation. The research findings contribute to improving English teaching and learning quality in Vietnam in general and in Tay Do University in particular. Article visualizations

THE DIFFICULTIES IN ORAL PRESENTATION OF ENGLISH-MAJORED JUNIORS AT TAY DO UNIVERSITY, VIETNAM

It could be broadly accepted that oral presentations are becoming important for students. It is required in almost every field and in the university environment. To succeed in the university environment and in their future jobs, these students need to improve their oral presentation skills. However, one of the drawbacks of using oral presentations in the language classroom is that students often find oral presentations extremely challenging. Therefore, the researcher conducted this research with the main goal of finding out common problems when giving an oral presentation to English-majored juniors at Tay Do University. Ninety juniors majoring in English at Tay Do University were selected to take part in the study. Data are gathered through questionnaires and interviews. The researcher used quantitative and qualitative methods to do the research. From the collected data, when they give a presentation, students usually make some mistakes such as problems in vocabulary, grammar, pronunciation, psychological and background knowledge. Through this study, they would recognize their own problems when giving a presentation. Besides, understanding students' learning difficulties may also enable teachers to help students develop effective learning strategies and ultimately improve their presentation skills. It is hoped that this research can be helpful for not only students but also teachers in learning and teaching English.  Article visualizations