Physical-chemical and microbiological changes in Cerrado Soil under differing sugarcane harvest management systems

Background: Sugarcane cultivation plays an important role in Brazilian economy, and it is expanding fast, mainly due to the increasing demand for ethanol production. In order to understand the impact of sugarcane cultivation and management, we studied sugarcane under different management regimes (pre-harvest burn and mechanical, unburnt harvest, or green cane), next to a control treatment with native vegetation. The soil bacterial community structure (including an evaluation of the diversity of the ammonia oxidizing (amoA) and denitrifying (nirK) genes), greenhouse gas flow and several soil physicochemical properties were evaluated. Results: Our results indicate that sugarcane cultivation in this region resulted in changes in several soil properties. Moreover, such changes are reflected in the soil microbiota. No significant influence of soil management on greenhouse gas fluxes was found. However, we did find a relationship between the biological changes and the dynamics of soil nutrients. In particular, the burnt cane and green cane treatments had distinct modifications. There were significant differences in the structure of the total bacterial, the ammonia oxidizing and the denitrifying bacterial communities, being that these groups responded differently to the changes in the soil. A combination of physical and chemical factors was correlated to the changes in the structures of the total bacterial communities of the soil. The changes in the structures of the functional groups follow a different pattern than the physicochemical variables. The latter might indicate a strong influence of interactions among different bacterial groups in the N cycle, emphasizing the importance of biological factors in the structuring of these communities. Conclusion: Sugarcane land use significantly impacted the structure of total selected soil bacterial communities and ammonia oxidizing and denitrifier gene diversities in a Cerrado field site in Central Brazil. A high impact of land use was observed in soil under the common burnt cane management. The green cane soil also presented different profiles compared to the control soil, but to at a lesser degree.

Parent psychopathology and offspring mental disorders: results from the WHO World Mental Health Surveys

Background Associations between specific parent and offspring mental disorders are likely to have been overestimated in studies that have failed to control for parent comorbidity. Aims To examine the associations of parent with respondent disorders. Method Data come from the World Health Organization (WHO) World Mental Health Surveys (n = 51 507). Respondent disorders were assessed with the Composite International Diagnostic Interview and parent disorders with informant-based Family History Research Diagnostic Criteria interviews. Results Although virtually all parent disorders examined (major depressive, generalised anxiety, panic, substance and antisocial behaviour disorders and suicidality) were significantly associated with offspring disorders in multivariate analyses, little specificity was found. Comorbid parent disorders had significant sub-additive associations with offspring disorders. Population-attributable risk proportions for parent disorders were 12.4% across all offspring disorders, generally higher in high- and upper-middle-than low-/lower-middle-income countries, and consistently higher for behaviour (11.0-19.9%) than other (7.1-14.0%) disorders. Conclusions Parent psychopathology is a robust non-specific predictor associated with a substantial proportion of offspring disorders.

Increased bursting glutamatergic neurotransmission in an auditory forebrain area of the zebra finch (Taenopygia guttata) induced by auditory stimulation

The caudomedial nidopallium (NCM) is a telencephalic area involved in auditory processing and memorization in songbirds, but the synaptic mechanisms associated with auditory processing in NCM are largely unknown. To identify potential changes in synaptic transmission induced by auditory stimulation in NCM, we used a slice preparation for path-clamp recordings of synaptic currents in the NCM of adult zebra finches (Taenopygia guttata) sacrificed after sound isolation followed by exposure to conspecific song or silence. Although post-synaptic GABAergic and glutamatergic currents in the NCM of control and song-exposed birds did not present any differences regarding their frequency, amplitude and duration after song exposure, we observed a higher probability of generation of bursting glutamatergic currents after blockade of GABAergic transmission in song-exposed birds as compared to controls. Both song-exposed males and females presented an increase in the probability of the expression of bursting glutamatergic currents, however bursting was more commonly seen in males where they appeared even without blocking GABAergic transmission. Our data show that song exposure changes the excitability of the glutamatergic neuronal network, increasing the probability of the generation of bursts of glutamatergic currents, but does not affect basic parameters of glutamatergic and GABAergic synaptic currents.