RESUMO
While the influence of high-status peers on maladaptive behaviors is well-documented, socialization processes of prosocial behavior through high-status peers remain understudied. This study examined whether adolescents' prosocial behavior was influenced by the prosocial behavior of the peers they liked and whether this effect was stronger when the peers they liked were also well-liked by their classmates. Three waves of data, six months apart, were collected among Chilean early adolescents who completed peer nominations and ratings at Time 1 (n = 294, Mage = 13.29, SD = 0.62; 55.1% male), Time 2 (n = 282), and Time 3 (n = 275). Longitudinal social network analyses showed that adolescents adopted the prosocial behavior of the classmates they liked - especially if these classmates were well-liked by peers in general. In addition, adolescents low in likeability were more susceptible to this influence than adolescents high in likeability. The influence resulted both in increases and - especially - decreases in prosocial behavior, depending on the level of prosociality of the liked peer. Findings suggest that likeability represents an important aspect of peer status that may be crucial for understanding the significance of peer influence with respect to prosocial behaviors during adolescence. Pre-Registration: https://osf.io/u4pxm .
RESUMO
Marine thraustochytrids produce metabolically important lipids such as the long-chain omega-3 polyunsaturated fatty acids, carotenoids, and sterols. The growth and lipid production in thraustochytrids depends on the composition of the culture medium that often contains yeast extract as a source of amino acids. This work discusses the effects of individual amino acids provided in the culture medium as the only source of nitrogen, on the production of biomass and lipids by the thraustochytrid Thraustochytrium sp. RT2316-16. A reconstructed metabolic network based on the annotated genome of RT2316-16 in combination with flux balance analysis was used to explain the observed growth and consumption of the nutrients. The culture kinetic parameters estimated from the experimental data were used to constrain the flux via the nutrient consumption rates and the specific growth rate of the triacylglycerol-free biomass in the genome-scale metabolic model (GEM) to predict the specific rate of ATP production for cell maintenance. A relationship was identified between the specific rate of ATP production for maintenance and the specific rate of glucose consumption. The GEM and the derived relationship for the production of ATP for maintenance were used in linear optimization problems, to successfully predict the specific growth rate of RT2316-16 in different experimental conditions.
Assuntos
Modelos Biológicos , Estramenópilas , Estramenópilas/metabolismo , Estramenópilas/genética , Meios de Cultura/química , Meios de Cultura/metabolismo , Redes e Vias Metabólicas/genética , Aminoácidos/metabolismo , Biomassa , Metabolismo dos Lipídeos , Nutrientes/metabolismo , Trifosfato de Adenosina/metabolismoRESUMO
As most studies on the link between peer status and prosocial behavior are cross-sectional, conducted with children, and operationalize status as the difference between acceptance and rejection, it remains unclear whether peer acceptance and rejection are consequences or prerequisites of prosocial behavior in adolescence. To fill this gap, this study examines the bidirectional associations of prosocial behavior with peer acceptance and peer rejection with data collected at 3 time points, 6 months apart, in a sample of 660 early Chilean adolescents (M = 12.94, SD = 0.62; 55.1% boys). Cross-lagged panel analyses showed that prosocial behavior positively predicted future peer acceptance, whereas peer acceptance had no significant effect on future prosocial behavior. The association between rejection and prosocial behavior was negative and bidirectional between Time 1 and Time 2. When a new academic year began, between Time 2 and Time 3, prosocial behavior negatively predicted rejection, whereas rejection in the previous grade level was positively associated with prosocial behavior at the beginning of the next grade. Multi-group panel analyses did not detect significant differences between boys and girls in the cross-lagged associations of prosociality with peer acceptance and peer rejection. The results suggest that acting prosocially can make adolescents better liked by their peers and highlight the possible importance of the transition to a new academic year for the prosocial behavior of previously rejected students. Implications for future research on peer relations are discussed.
Assuntos
Comportamento do Adolescente , Altruísmo , Criança , Masculino , Feminino , Adolescente , Humanos , Estudos Transversais , Estudos Longitudinais , Grupo Associado , Relações Interpessoais , Comportamento SocialRESUMO
Cross-ethnic friendships offer a unique opportunity for improving intergroup relations and reduce prejudice, yet ethnic segregation of friendship networks is often seen as a major obstacle to the integration of immigrant students in educational contexts. This article examines the role of perspective-taking abilities and prejudice towards low social class peers on the probability of cross-ethnic friendships in a sample of 242 students from five multicultural classrooms in Chile (Mage = 12.3; SD = 0.69, 45% girls). It was expected that students who reported high levels of perspective-taking abilities and low levels of prejudice towards low social class peers were more likely to form and maintain cross-ethnic friendships. Longitudinal network analysis (RSiena) was used to examine these hypotheses, confirming the role of both variables in fostering (and reducing) friendships among Chilean and immigrant adolescents. Results are discussed in light of an intersectional framework between social class and ethnicity. Implications for social-emotional interventions in multicultural educational contexts are also discussed.
Assuntos
Etnicidade , Amigos , Adolescente , Criança , Feminino , Humanos , Relações Interpessoais , Estudos Longitudinais , Masculino , Grupo Associado , Preconceito , Classe SocialRESUMO
A novel conotoxin, named as PiVIIA, was isolated from the venom of Conus princeps, a marine predatory cone snail collected in the Pacific Southern Coast of Mexico. Chymotryptic digest of the S-alkylated peptide in combination with liquid chromatography coupled to tandem mass spectrometry, were used to define the sequencing of this peptide. Eleven N-terminal amino acids were verified by automated Edman degradation. PiVIIA is a 25-mer peptide (CDAOTHYCTNYWγCCSGYCγHSHCW) with six cysteine residues forming three disulphide bonds, a hydroxyproline (O) and two gamma carboxyglutamic acid (γ) residues. Based on the arrangement of six Cys residues (C-C-CC-C-C), this conotoxin might belong to the O2-superfamily. Moreover, PiVIIA has a conserved motif (-γCCS-) that characterizes γ-conotoxins from molluscivorous Conus. Peptide PiVIIA has 45% sequence identity with γ-PnVIIA-the prototype of this family. Biological activity of PiVIIA was assessed by voltage-clamp recording in rat dorsal root ganglion neurons. Perfusion of PiVIIA in the µM range produces a significant increase in the Ca(2+) currents, without significantly modifying the Naâº, K⺠or proton-gated acid sensing ionic currents. These results indicate that PiVIIA is a new conotoxin whose activity deserves further studies to define its potential use as a positive modulator of neuronal activity.
Assuntos
Canais de Cálcio/fisiologia , Conotoxinas/farmacologia , Caramujo Conus , Neurônios/efeitos dos fármacos , Peptídeos/farmacologia , Sequência de Aminoácidos , Animais , Conotoxinas/química , Conotoxinas/isolamento & purificação , Feminino , Gânglios Espinais/citologia , Gânglios Espinais/fisiologia , Masculino , Dados de Sequência Molecular , Neurônios/fisiologia , Peptídeos/química , Peptídeos/isolamento & purificação , Ratos Long-EvansRESUMO
BACKGROUND: Coccidioidomycosis is a systemic fungal disease caused by Coccidioides spp. Patients with phagocytic, cellular, or humoral immunodeficiencies exhibit immunodeficiencies that confer increased susceptibility to fungal infections. In Mexico there is an underreporting of this disease and no studies currently describe the immune status of these patients in an endemic area. OBJECTIVE: To describe the clinical and immunological characteristics of pediatric patients with coccidioidomycosis. MATERIALS AND METHODS: Pediatric patients with diagnosis of coccidioidomycosis from two tertiary level hospitals of northeastern Mexico were included, from the period 2008-2012; immune status was assessed by clinical history, immunoglobulins levels, levels of lymphocytes T, B, and NK (natural killer), and the nitroblue tetrazolium test. RESULTS: Thirty patients were included, 18 male (60%). The age at diagnosis was five years (median, range 0.25-13). Twelve were from Coahuila (40%). Residual pulmonary coccidioidomycosis was the clinical type presentation found in 16 patients (53%). A primary humoral immunodeficiency was found in three patients (10%) and a secondary immunodeficiency in another three (10%). Case fatality rate was 16%. CONCLUSIONS: . The disease predominated in male patients. In 33% of patients, levels of IgG were elevated, probably due to stimulation by chronic fungal infection. In 20% of patients, immunodeficiency was documented. There was a high mortality rate.