Maturation of subtilisin-like protease NbSLP1 from microsporidia Nosema bombycis.

Microsporidia are obligate intracellular parasites and possess a unique way of invading hosts, namely germination. Microsporidia are able to infect almost all animal cells by germination. During the process, the polar tube extrudes from the spores within, thus injecting infectious sporoplasm into the host cells. Previous studies indicated that subtilisin-like protease 1 (NbSLP1) of microsporidia Nosema bombycis were located at the polar cap of germinated spores where the polar tube extrusion. We hypothesized that NbSLP1 is an essential player in the germination process. Normally, SLP need to be activated by autoproteolysis under conditions. In this study, we found that the signal peptide of NbSLP1 affected the activation of protease, two self-cleavage sites were involved in NbSLP1 maturation between Ala104Asp105 and Ala124Asp125 respectively. Mutants at catalytic triad of NbSLP1 confirmed the decreasing of autoproteolysis. This study demonstrates that intramolecular proteolysis is required for NbSLP1 maturation. The protease undergoes a series of sequential N-terminal cleavage events to generate the mature enzyme. Like other subtilisin-like enzymes, catalytic triad of NbSLP1 are significant for the self-activation of NbSLP1. In conclusion, clarifying the maturation of NbSLP1 will be valuable for understanding the polar tube ejection mechanism of germination.

Heterologous Expressed NbSWP12 from Microsporidia Nosema bombycis Can Bind with Phosphatidylinositol 3-Phosphate and Affect Vesicle Genesis.

Microsporidia are a big group of single-celled obligate intracellular organisms infecting most animals and some protozoans. These minimalist eukaryotes lack numerous genes in metabolism and vesicle trafficking. Here, we demonstrated that the spore wall protein NbSWP12 of microsporidium Nosema bombycis belongs to Bin/Amphiphysin/Rvs (BAR) protein family and can specifically bind with phosphatidylinositol 3-phosphate [Ptdlns(3)P]. Since Ptdlns(3)P is involved in endosomal vesicle biogenesis and trafficking, we heterologous expressed NbSWP12 in yeast Saccharomyces cerevisiae and proved that NbSWP12 can target the cell membrane and endocytic vesicles. Nbswp12 transformed into Gvp36 (a BAR protein of S. cerevisiae) deletion mutant rescued the defect phenotype of vesicular traffic. This study identified a BAR protein function in vesicle genesis and sorting and provided clues for further understanding of how microsporidia internalize nutrients and metabolites during proliferation.

Academic procrastination precedes problematic mobile phone use in Chinese adolescents: A longitudinal mediation model of distraction cognitions.

Cross-sectional studies have documented a positive association between academic procrastination and problematic mobile phone use (PMPU). However, the specific predictive direction has remained controversial and the potential mechanisms underlying the association have not been rigorously evaluated. According to Davis's cognitive-behavioral model, Brand et al.'s I-PACE model, and procrastination-related theories, academic procrastination and PMPU might have a reciprocal relationship and distraction cognitions might play a mediating role in this process. A total of 633 secondary school students completed three self-report questionnaires at three 6-month intervals over the course of 1.5 years. The cross-lagged panel model results showed that earlier academic procrastination positively predicted subsequent PMPU over time, but the reverse prediction was not stable. Furthermore, distraction cognitions played a mediating role in linking earlier academic procrastination and subsequent PMPU. These findings indicate that academic procrastination precedes PMPU with distraction cognitions as a potential mediator, which contributes to clarifying the controversial relationship and explicating the underlying mechanism. Overall, interventions for academic procrastination may be effective in reducing maladaptive cognitions associated with mobile phones and preventing adolescents from developing PMPU.

Social Media Exposure and College Students' Mental Health During the Outbreak of COVID-19: The Mediating Role of Rumination and the Moderating Role of Mindfulness.

In response to reports of people experiencing varying levels of anxiety and depression during the outbreak of COVID-19, researchers have argued that exposure to related information on social media is a salient contributing factor. Based on the integrated model of ruminative response style and the diathesis-stress model, it has been suggested that incorporating rumination and mindfulness may elucidate the potential mechanism underlying the aforementioned association. This study aimed to examine the mediating role of rumination and the moderating role of mindfulness in the association between social media exposure (SME) to COVID-19 information and psychological distress. The results from online questionnaire responses of 439 college students from two universities in Wuhan, Hubei Province, showed that rumination mediated the association between SME and psychological distress. Furthermore, mindfulness was revealed as a protective factor that buffered the adverse effect of SME on psychological distress through rumination. These findings advance a better understanding of the formation process of psychological symptoms during the COVID-19 pandemic and provide insights regarding effective interventions for adverse mental health consequences in college students.

Mobile phone addiction and cognitive failures in daily life: The mediating roles of sleep duration and quality and the moderating role of trait self-regulation.

Previous studies have reported well-documented findings that mobile phone addiction (MPA) is associated with negative emotion-related consequences; however, sporadic research has investigated the associations between MPA and cognitive outcomes related to daily cognitive functioning. Sleep duration, sleep quality, and trait self-regulation are thought to be linked to this association. The present study aimed to examine the mediating roles of sleep duration and quality and the moderating role of trait self-regulation between MPA and daily cognitive failures. A total of 1721 secondary school students were recruited to complete four self-reported questionnaires. The model results indicated that sleep quality (but not sleep duration) partially mediated the association between MPA and daily cognitive failures, and high levels of trait self-regulation could attenuate the potential impact of MPA on daily cognitive failures through sleep quality. Overall, these findings address the issue of how and when MPA is linked with cognitive performance in daily life, which can advance a better understanding of the negative consequences induced by MPA. Limitations and implications are discussed.

A computer-based Pinyin intervention for disadvantaged children in China: Effects on Pinyin skills, phonological awareness, and character reading.

Pinyin is an alphabetic script that denotes pronunciations of Chinese characters. Studies have shown that Pinyin instruction enhances both phonological awareness (e.g., Shu et al., Developmental Science, 2008, 11, 171-181) and character reading (e.g., Lin et al., Psychological Science, 2010, 21, 1117-1122) in Chinese children. In the present study, we provided a 3-week Pinyin intervention with a computer-based Pinyin GraphoGame to disadvantaged migrant children with poor Pinyin skills. A total of 252 first graders who were children of migrant workers in a large Chinese city were assessed to identify poor Pinyin readers. Fifty-six 7-year-old children with poor Pinyin skills were selected and randomly divided into a training group and a control group, with 28 children in each group. The training group played the Pinyin GraphoGame for 3 weeks, while the control group received school instruction only during the same period. Results showed that the children in the training group outperformed their peers in the control group on Pinyin reading accuracy and fluency, onset-rime and phonemic awareness, and character reading. These results suggest that the Pinyin GraphoGame may be a cost-effective method to enhance Pinyin and literacy outcomes for underprivileged children in China.

High-definition transcranial direct current stimulation (HD-tDCS) of left dorsolateral prefrontal cortex affects performance in Balloon Analogue Risk Task (BART).

Background: Studies on risk preferences have long been of great concern and have examined the neural basis underlying risk-based decision making. However, studies using conventional transcranial direct current stimulation (tDCS) revealed that bilateral stimulation could change risk propensity with limited evidence of precisely focalized unilateral high-definition transcranial direct current stimulation (HD-tDCS). The aim of this experiment was to investigate the effect of HD-tDCS focalizing the left dorsal lateral prefrontal cortex (DLPFC) on risk-taking behavior during the Balloon Analogue Risk Task (BART). Methods: This study was designed as a between-subject, single-blind, sham-controlled experiment. University students were randomly assigned to three groups: the anodal group (F3 anode, AF3, F1, F5, FC3 returned), the cathodal group (F3 cathodal, AF3, F1, F5, FC3 returned) and the sham group. Subsequently, 1.5-mA 20-min HD-tDCS was applied during the BART, and the Positive Affect and Negative Affect Scale (PANAS), the Sensation Seeking Scale-5 (SSS-5), and the Behavioral Inhibition System and Behavioral Approach System scale (BIS/BAS) were measured as control variables. Results: The cathodal group earned less total money than the sham group, and no significant difference was observed between the anodal group and the sham group. Conclusions: These results showed that, to some extent, focalized unilateral cathodal HD-tDCS on left DLPFC could change performance during risky tasks and diminish risky decision making. Further studies are needed to investigate the dose effect and electrode distribution of HD-tDCS during risky tasks and examine synchronous brain activity to show the neural basis.