Crystal Structure of the Heteromolecular Chaperone, AscE-AscG, from the Type III Secretion System in Aeromonas hydrophila

10.1371/journal.pone.0019208PLoS ONE64

Hijacking of the Pleiotropic Cytokine Interferon-γ by the Type III Secretion System of Yersinia pestis

Yersinia pestis, the causative agent of bubonic plague, employs its type III secretion system to inject toxins into target cells, a crucial step in infection establishment. LcrV is an essential component of the T3SS of Yersinia spp, and is able to associate at the tip of the secretion needle and take part in the translocation of anti-host effector proteins into the eukaryotic cell cytoplasm. Upon cell contact, LcrV is also released into the surrounding medium where it has been shown to block the normal inflammatory response, although details of this mechanism have remained elusive. In this work, we reveal a key aspect of the immunomodulatory function of LcrV by showing that it interacts directly and with nanomolar affinity with the inflammatory cytokine IFNγ. In addition, we generate specific IFNγ mutants that show decreased interaction capabilities towards LcrV, enabling us to map the interaction region to two basic C-terminal clusters of IFNγ. Lastly, we show that the LcrV-IFNγ interaction can be disrupted by a number of inhibitors, some of which display nanomolar affinity. This study thus not only identifies novel potential inhibitors that could be developed for the control of Yersinia-induced infection, but also highlights the diversity of the strategies used by Y. pestis to evade the immune system, with the hijacking of pleiotropic cytokines being a long-range mechanism that potentially plays a key role in the severity of plague

Modified Needle-Tip PcrV Proteins Reveal Distinct Phenotypes Relevant to the Control of Type III Secretion and Intoxication by Pseudomonas aeruginosa

The type III secretion system (T3SS) is employed to deliver effector proteins to the cytosol of eukaryotic hosts by multiple species of Gram-negative bacteria, including Pseudomonas aeruginosa. Translocation of effectors is dependent on the proteins encoded by the pcrGVHpopBD operon. These proteins form a T3S translocator complex, composed of a needle-tip complex (PcrV), translocons (PopB and PopD), and chaperones (PcrG and PcrH). PcrV mediates the folding and insertion of PopB/PopD in host plasmic membranes, where assembled translocons form a translocation channel. Assembly of this complex and delivery of effectors through this machinery is tightly controlled by PcrV, yet the multifunctional aspects of this molecule have not been defined. In addition, PcrV is a protective antigen for P. aeruginosa infection as is the ortholog, LcrV, for Yersinia. We constructed PcrV derivatives containing in-frame linker insertions and site-specific mutations. The expression of these derivatives was regulated by a T3S-specific promoter in a pcrV-null mutant of PA103. Nine derivatives disrupted the regulation of effector secretion and constitutively released an effector protein into growth medium. Three of these regulatory mutants, in which the linker was inserted in the N-terminal globular domain, were competent for the translocation of a cytotoxin, ExoU, into eukaryotic host cells. We also isolated strains expressing a delayed-toxicity phenotype, which secrete translocators slowly despite the normal level of effector secretion. Most of the cytotoxic translocation-competent strains retained the protective epitope of PcrV derivatives, and Mab166 was able to protect erythrocytes during infection with these strains. The use of defined PcrV derivatives possessing distinct phenotypes may lead to a better understanding of the functional aspects of T3 needle-tip proteins and the development of therapeutic agents or vaccines targeting T3SS-mediated intoxication

Meal preparation and consumption before and during the COVID-19 pandemic: The relationship with cooking skills of Brazilian university students

OBJECTIVE: This study aimed to analyze meal preparation and the place of its consumption by university students before and during the COVID-19 pandemic, according to their individual characteristics and cooking skills. METHODS: Data were collected with 1919 Brazilian university students using the Brazilian Cooking Skills Questionnaire (BCSQ) and questions about gender, living arrangement, knowing how to cook and location of meal consumption. Bayesian multilevel ordinal regression models were used to estimate the probabilities of meal preparation and local location of its consumption by Brazilian university students before and during the COVID-19 pandemic, according to their individual characteristics and cooking skills. RESULTS: Most of participants showed reported a high level of cooking skills (70.7%). Also, they reported a decrease in ordering delivery of take-away food and eating fast-food, while increasing homemade meals with fresh ingredients, ultra-processed food or both during the pandemic compared to the period before the quarantine. Lastly, they increased their cooking frequency during the pandemic, regardless of their cooking skills level. However, the group with high cooking skills had a greater increase in the use of fresh ingredients. CONCLUSIONS: The study showed that the pandemic was an opportunity for university students to increase their cooking skills and frequency of cooking at home with a variety of foods. Particular attention should be given to those with low cooking skills and that use ultra-processed foods, promoting interventions to disseminate information and with behavior change components to teach about healthy cooking to increase cooking knowledge and skills, focusing on preparation of fresh ingredients

Brazilian Cooking Skills Questionnaire evaluation of using/cooking and consumption of fruits and vegetables

Objective Young adults are often faced with barriers to cooking their own food. These barriers are associated with poor diet. The aim of this study was to explore the factor structure of the Brazilian Cooking Skills and Healthy Eating Questionnaire (BCSQ) to identify the barriers to cooking, use, and consumption of fruits and vegetables by young adults. Methods Data were collected from a baseline study with Brazilian university students (N = 767). Forty-eight items from the BCSQ (composed of the following scales: Cooking Attitude, Cooking Behavior, Produce Consumption Self-Efficacy, Cooking Self-Efficacy, Self-Efficacy in Using Cooking Techniques, and Self-Efficacy in Using Fruits, Vegetables, and Seasonings) were submitted to exploratory factor analysis, confirmatory factor analysis (ten fit indexes), and internal consistency reliability evaluation. Multilevel linear regression models were used to analyze variations on the BCSQ dimensions by sex, living arrangements, knowledge of how to cook, location of main meal, and time available for cooking. Results The 20-item BCSQ showed good fit indexes. The items based on negative cooking attitudes, frequency of using leftovers, and self-efficacy related to cooking from scratch, using and eating fruits and vegetables were adequate for the evaluation of cooking skills. These items represent and reflect the health dimensions applied to this research. The self-efficacy in using cooking techniques, which was not validated in previous study scale, was excluded due to its dimension. Conclusions These results enabled us to shorten the BCSQ, which can be used to evaluate the barriers to cooking among young adults, as well as measuring their healthy eating practices, supporting future research and programs

Student-Athletes' Motivation and Identity: Variation Among Brazilian and Portuguese University Student-Athletes

This study examined the variation of student-athletes’ identity and motivation across Portuguese and Brazilian universities, accounting for variation in gender, studentathletes’ training hours per week, sports level, student-athletes status within each university, and university type. We initially established the validity of the Baller Identity Measurement Scale questionnaire and the Student-Athletes’ Motivation toward Sports and Academics Questionnaire-based observations among 441 Brazilian and Portuguese student-athletes. Then, the validated version of the questionnaires was applied to a total sample of 765 student-athletes from Brazil (n¼ 568) and Portugal (n ¼ 197). We further considered individual (hours of training and student-athlete status) and contextual characteristics (university type and country). Multilevel regression and poststratification were used to estimate each studentathlete identity and motivation as a function of his or her individual and contextual characteristics. Overall, the predictions showed that cultural (country), academic (type of university), and athletic (training hours) context likely have a substantial influence on student-athletes’ identity and motivation.1113-FF28-6C5F | Carlos Eduardo Barros Gonçalvesinfo:eu-repo/semantics/publishedVersio

Factors Influencing Student-Athletes' Identity: A Multilevel Regression and Poststratification Approach

We considered identity variation among Brazilian university student-athletes in relation to their gender, sport type, competition level, and university type. Participants were 506 student-athletes (219 males and 287 females) from public and private Brazilian universities, competing in team and individual sports, at local, state, and national levels. We used multilevel regression and poststratification to estimate each participant’s identity from the aforementioned variables. Gender and sport type were not associated with any substantial identify variation, but there were higher values on Baller Identity Measurement Scale dimensions for student-athletes from public versus private universities, and student-athletes competing at the highest level had lower Baller Identity Measurement Scale values compared to peers competing at lower levels. Overall, university type and sport competitive level were the contextual factors that most influenced Brazilian student-athletes’ identities.1113-FF28-6C5F | Carlos Eduardo Barros Gonçalvesinfo:eu-repo/semantics/publishedVersio