4-S Positive Youth Development in Latin America: Professional Schools in Costa Rica

As youth development programs established in the United States expand globally, researchers must evaluate their impacts in diverse contexts. The work described in this article established a baseline for assessing the impact of a 4-S youth program at professional technical high schools in Costa Rica. The 4-S program is equivalent to 4-H in English-speaking countries. Results indicate that members of the 4-S program exhibited significantly higher levels of positive youth development than youths in the comparison group (p \u3c .001). We consider how these findings speak to the importance of promoting programs such as 4-S, and we conclude by discussing the implications of this work for practitioners

The Importance of pH in Regulating the Function of the Fasciola hepatica Cathepsin L1 Cysteine Protease

The helminth parasite Fasciola hepatica secretes cathepsin L cysteine proteases to invade its host, migrate through tissues and digest haemoglobin, its main source of amino acids. Here we investigated the importance of pH in regulating the activity and functions of the major cathepsin L protease FheCL1. The slightly acidic pH of the parasite gut facilitates the auto-catalytic activation of FheCL1 from its inactive proFheCL1 zymogen; this process was ∼40-fold faster at pH 4.5 than at pH 7.0. Active mature FheCL1 is very stable at acidic and neutral conditions (the enzyme retained ∼45% activity when incubated at 37°C and pH 4.5 for 10 days) and displayed a broad pH range for activity peptide substrates and the protein ovalbumin, peaking between pH 5.5 and pH 7.0. This pH profile likely reflects the need for FheCL1 to function both in the parasite gut and in the host tissues. FheCL1, however, could not cleave its natural substrate Hb in the pH range pH 5.5 and pH 7.0; digestion occurred only at pH≤4.5, which coincided with pH-induced dissociation of the Hb tetramer. Our studies indicate that the acidic pH of the parasite relaxes the Hb structure, making it susceptible to proteolysis by FheCL1. This process is enhanced by glutathione (GSH), the main reducing agent contained in red blood cells. Using mass spectrometry, we show that FheCL1 can degrade Hb to small peptides, predominantly of 4–14 residues, but cannot release free amino acids. Therefore, we suggest that Hb degradation is not completed in the gut lumen but that the resulting peptides are absorbed by the gut epithelial cells for further processing by intracellular di- and amino-peptidases to free amino acids that are distributed through the parasite tissue for protein anabolism

Phenotypic Screen of Early-Developing Larvae of the Blood Fluke, Schistosoma mansoni, using RNA Interference

RNA interference (RNAi) represents the only method currently available for manipulating gene-specific expression in Schistosoma spp., although application of this technology as a functional genomic profiling tool has yet to be explored. In the present study 32 genes, including antioxidants, transcription factors, cell signaling molecules and metabolic enzymes, were selected to determine if gene knockdown by RNAi was associated with morphologically definable phenotypic changes in early intramolluscan larval development. Transcript selection was based on their high expression in in vitro cultured S. mansoni primary sporocysts and/or their potential involvement in developmental processes. Miracidia were allowed to transform to sporocysts in the presence of synthesized double-stranded RNAs (dsRNAs) and cultivated for 7 days, during which time developing larvae were closely observed for phenotypic changes including failure/delay in transformation, loss of motility, altered growth and death. Of the phenotypes evaluated, only one was consistently detected; namely a reduction in sporocyst size based on length measurements. The size-reducing phenotype was observed in 11 of the 33 (33%) dsRNA treatment groups, and of these 11 phenotype-associated genes (superoxide dismutase, Smad1, RHO2, Smad2, Cav2A, ring box, GST26, calcineurin B, Smad4, lactate dehydrogenase and EF1α), only 6 demonstrated a significant and consistent knockdown of specific transcript expression. Unexpectedly one phenotype-linked gene, superoxide dismutase (SOD), was highly induced (∼1600-fold) upon dsRNA exposure. Variation in dsRNA-mediated silencing effects also was evident in the group of sporocysts that lacked any definable phenotype. Out of 22 nonphenotype-expressing dsRNA treatments (myosin, PKCB, HEXBP, calcium channel, Sma2, RHO1, PKC receptor, DHHC, PepcK, calreticulin, calpain, Smeg, 14.3.3, K5, SPO1, SmZF1, fibrillarin, GST28, GPx, TPx1, TPx2 and TPx2/TPx1), 12 were assessed for the transcript levels. Of those, 6 genes exhibited consistent reductions in steady-state transcript levels, while expression level for the rest remained unchanged. Results demonstrate that the efficacy of dsRNA-treatment in producing consistent phenotypic changes and/or altered gene expression levels in S. mansoni sporocysts is highly dependent on the selected gene (or the specific dsRNA sequence used) and the timing of evaluation after treatment. Although RNAi holds great promise as a functional genomics tool for larval schistosomes, our finding of potential off-target or nonspecific effects of some dsRNA treatments and variable efficiencies in specific gene knockdown indicate a critical need for gene-specific testing and optimization as an essential part of experimental design, execution and data interpretation

A Research Agenda for Helminth Diseases of Humans: Basic Research and Enabling Technologies to Support Control and Elimination of Helminthiases

Successful and sustainable intervention against human helminthiases depends on optimal utilisation of available control measures and development of new tools and strategies, as well as an understanding of the evolutionary implications of prolonged intervention on parasite populations and those of their hosts and vectors. This will depend largely on updated knowledge of relevant and fundamental parasite biology. There is a need, therefore, to exploit and apply new knowledge and techniques in order to make significant and novel gains in combating helminthiases and supporting the sustainability of current and successful mass drug administration (MDA) programmes. Among the fields of basic research that are likely to yield improved control tools, the Disease Reference Group on Helminth Infections (DRG4) has identified four broad areas that stand out as central to the development of the next generation of helminth control measures: 1) parasite genetics, genomics, and functional genomics; 2) parasite immunology; 3) (vertebrate) host–parasite interactions and immunopathology; and 4) (invertebrate) host–parasite interactions and transmission biology. The DRG4 was established in 2009 by the Special Programme for Research and Training in Tropical Diseases (TDR). The Group was given the mandate to undertake a comprehensive review of recent advances in helminthiases research in order to identify notable gaps and highlight priority areas. This paper summarises recent advances and discusses challenges in the investigation of the fundamental biology of those helminth parasites under the DRG4 Group's remit according to the identified priorities, and presents a research and development agenda for basic parasite research and enabling technologies that will help support control and elimination efforts against human helminthiases

Maturation or disruption? Conscientiousness development in the transition into adolescence

Research to date has shown longitudinal changes in conscientiousness during early and middle adolescence, but most studies have been conducted in Western countries. The present study aimed to examine the pattern of mean-level conscientiousness change at the transition into early adolescence among a Chinese sample using curve of factors (CUFFS) models. Four waves of data from 661 Chinese children aged 8 years old at baseline in the China Family Panel Studies were used. Parents were asked to rate their children’s level of conscientiousness every 2 years. On average, mean-level conscientiousness showed a decelerating increase. Girls had higher average conscientiousness levels than boys, but they did not differ in change patterns. The inconsistency between the current study and previous research indicates that conscientiousness development may depend, in part, on cultural factors

Self-Regulation Across Adolescence: Exploring the Structure of Selection, Optimization, and Compensation

Intentional self-regulation (ISR) is thought to undergo significant development during the second decade of life, but our understanding of ISR's development during this period remains incomplete. We discuss the development of ISR as operationalized by Freund & Baltes's (2002) measure of selection, optimization, and compensation (SOC). We use data from 5,471 youth that had participated in the 4-H Study of Positive Youth Development in Grades 5 through 12. Using exploratory factor analyses, our findings suggest that the SOC questionnaire adheres to a stable three-factor structure across adolescence, with factors representing selection, intentional self-regulation, and a reverse-coded method factor. We discuss the implications of our findings for future research

Commentary on Ellis et al. (2021)

No abstract available

Developmental trajectories of intentional self regulation in adolescence: the role of parenting and implications for positive and problematic outcomes among diverse youth

This study assessed 1574 Grades 5 to 11 youth (63.6% female) from the 4-H Study of Positive Youth Development (PYD), a longitudinal study involving U.S. adolescents, to assess if patterns of intentional self regulation (ISR) existed; whether these trajectories differed in relation to several Grade 5 parenting characteristics; and whether ISR trajectories were linked to positive and negative developmental outcomes at Grade 11. Growth mixture modeling identified a four-group solution of ISR trajectories: Steady Decline, Elevated, Late Onset, and Pronounced Decline. Most adolescents reported an incremental decrease in ISR from Grades 5 to 11 (Steady Decline). Lower levels of parental warmth, monitoring, and school involvement at Grade 5 predicted Late-Onset ISR development while Pronounced Decline adolescents reported lower levels of PYD and Contribution at Grade 11. We discuss the finding that youth at initially similar levels of ISR diverged over adolescence, while youth at initially disparate levels converged

Relational Developmental Dystems Theories of Positive Youth Development: Methodological Issues and Implications

Developmental systems theory provides powerful tools for predicting complex, dynamic interactions among biological and environmental processes in human behavior and health. This groundbreaking handbook provides a roadmap for integrating key concepts of developmental systems theory (such as self-organization, reciprocal dynamic interaction, and probabilistic epigenesis) and simulation models (connectionist and agent-based models) with advanced dynamic modeling approaches for testing these theories and models. Internationally renowned developmental science scholars present innovations in research design, measurement, and analysis that offer new means of generating evidence-based decisions to optimize the course of health and positive functioning across the life span. Topics include epigenetic development and evolution; the relationship between neural systems growth and psychological development; the role of family environments in shaping children\u27s cognitive skills and associated adult outcomes, and more