RESUMO
The microbiome represents a complex network among the various members of the community of microorganisms that are associated with a host. The composition of the bacterial community is essential to supplement multiple metabolic pathways that the host lacks, particularly in organisms with blood-sucking habits such as ticks. On the other hand, some endosymbionts showed some competence with potentially pathogenic microorganisms. Francisella-like endosymbionts (FLEs) encompass a group of gamma-proteobacterias that are closely related to Francisella tularensis, but are usually apathogenic, which brings nutrients like vitamin B and other cofactors to the tick. It has been postulated that the main route of transmission of FLE is vertical; however, evidence has accumulated regarding the possible mechanism of horizontal transmission. Despite growing interest in knowledge of endosymbionts in the Neotropical region, the efforts related to the establishment of their inventory for tick communities are concentrated in South and Central America, with an important gap in knowledge in Mesoamerican countries such as Mexico. For this reason, the aim of this work was to evaluate the presence and diversity of endosymbionts in the highly host-specialized tick Amblyomma nodosum collected from the anteater Tamandua mexicana in Mexico. We analysed 36 A. nodosum for the presence of DNA of endosymbiont (Coxiella and Francisella) and pathogenic (Anaplasma, Borrelia, Ehrlichia and Rickettsia) bacteria. The presence of a member of the genus Francisella and Candidatus Anaplasma brasiliensis was demonstrated. Our findings provide information on the composition of A. nodosum's microbiome, increasing the inventory of bacterial species associated with this hard tick on the American continent.
Assuntos
Amblyomma , Gammaproteobacteria , Amblyomma/microbiologia , Animais , Vermilingua/parasitologia , México , Gammaproteobacteria/classificação , Gammaproteobacteria/isolamento & purificação , Masculino , Feminino , FilogeniaRESUMO
BACKGROUND: Previous studies have evidenced that rumination and drinking motives may mediate the association between depressive symptoms and alcohol outcomes. The present study cross-culturally examined whether a similar mediation model may extend to marijuana. Specifically, we tested distinct rumination facets (problem-focused thoughts, counterfactual thinking, repetitive thoughts, and anticipatory thoughts) and marijuana use motives (social, coping, expansion, conformity, enhancement) as double-mediators of the paths from depressive symptoms to marijuana outcomes (use and consequences). METHOD: A comprehensive mediation path model was tested in a cross-sectional sample of college student marijuana users (nâ¯=â¯1175) from five countries (U.S., Argentina, Uruguay, Spain, Netherlands). Multi-group models were tested to determine if the proposed mediational model was invariant across sex and different cultures/countries. RESULTS: Depressive symptoms and marijuana outcomes were indirectly associated through ruminative thinking and marijuana motives. Specifically, higher depressive symptoms were associated with higher problem-focused thoughts; which in turn were associated with: a) higher endorsement of coping motives which in turn was associated with higher marijuana use and related consequences and b) lower endorsement of enhancement motives which in turn was associated with lower marijuana use and related consequences. The multi-group analyses showed that the model was invariant across sex and the five countries. CONCLUSIONS: The present research supports the existence of a universal (i.e., cross-national invariant) negative affect regulation pathway to marijuana use/misuse similar to those previously found with alcohol. Additional research is needed to confirm the role of enhancement motives in the associations of depression, rumination and marijuana outcomes.
Assuntos
Depressão/psicologia , Uso da Maconha/psicologia , Motivação , Ruminação Cognitiva , Estudantes/psicologia , Adolescente , Adulto , Argentina/epidemiologia , Estudos Transversais , Feminino , Humanos , Masculino , Uso da Maconha/epidemiologia , Países Baixos/epidemiologia , Espanha/epidemiologia , Estados Unidos/epidemiologia , Universidades , Uruguai/epidemiologia , Adulto JovemRESUMO
Marijuana internalized norms, measured by the Perceived Importance of Marijuana to the College Experience Scale (PIMCES; 8 items), has been found to be distinct from marijuana descriptive/injunctive norms and to be a unique robust predictor of marijuana-related outcomes among college students, yet the role of these beliefs has not been studied outside the U.S. Using confirmatory factor analysis, the present work examined the level of measurement invariance (i.e., configural, metric, and scalar) of the PIMCES across five different countries with distinct marijuana-related regulations (i.e., U.S., Argentina, Spain, Uruguay, and the Netherlands), sex, and marijuana user status among college students (nâ¯=â¯3424) recruited between September 2017 and January 2018. To make valid comparisons across groups, metric invariance is needed to compare correlations and scalar invariance is needed to compare latent means. We found strong measurement invariance (i.e., scalar invariance) for the PIMCES across countries, across males and females, and across marijuana users and non-users. College students in the U.S. reported the highest levels of marijuana internalized norms compared to college students from all other countries. As expected, males and marijuana users showed significantly higher scores on the PIMCES than females and non-users, respectively. Bivariate correlations between PIMCES scores and other marijuana-related variables were remarkably similar across males and females, though differences across countries warrant further exploration. Taken together, the degree to which college students view marijuana use to be an integral part of the college experience may be an important target for college student marijuana interventions across various countries/cultures.