Variabilidade genética de duas populações de Astyanax altiparanae da bacia do alto rio Paraná.

O presente trabalho tem como objetivo caracterizar a estrutura genética de duas populações de A. altiparanae da bacia do alto rio Paraná (Paranapanema e Tietê) através da análise de 11 marcadores moleculares do tipo microssatélite.Organizado por: Sílvio Ricardo Maurano; AQUACIÊNCIA 2012

CHALLENGE 6: Exposing the roots of mental disorders

Mental disorders have devastating and increasing impact in our societies. CSIC researchers face the challenge of determining the biological and social causes and consequences of these disorders, and of finding efficient therapies. To these aims, the collaborative effort of neuroscientists, neurologists, psychiatrists, psychologists and human and social scientists, the use and development of state-of-the-art technologies and the contact with patient associations and pharma industry are required.Peer reviewe

Transcriptomic changes linked to age-dependent neuromelanin accumulation in a new Parkinson's disease mouse model

Resumen del trabajo presentado en el 50th Annual Meeting Society for Neuroscience, celebrado de forma virtual del 8 al 11 de noviembre de 2021In Parkinson's disease (PD) there is a preferential degeneration of neuromelanin (NM)-containing neurons, especially neurons from the Substantia Nigra (SN) but also from the Ventral Tegmental Area (VTA) and Locus Coeruleus (LC). We generated a new NM-producing mouse model, based on the tissue-specific constitutive expression of human tyrosinase (hTyr) under the tyrosine hydroxylase (TH) promoter (tgNM), that mimics the distribution and age-dependent accumulation of NM in the human brain (i.e. catecholaminergic groups A1-A14). TgNM mice exhibited major PD features, including both motor and non-motor behavioral alterations, inclusion body formation, neuronal degeneration in lower brainstem areas (LC) together with neuronal dysfunction in higher brainstem areas (SN and VTA). In order to understand the mechanisms by which NM accumulation in specific brain areas ultimately interferes with the normal functioning of cells, we characterized genome-wide transcriptomic changes linked to the intracellular presence and progressive accumulation of NM in two NM-accumulating neuronal subpopulations (SN and VTA) that are known to be differentially susceptible to PD pathology. We selectively isolated single dopaminergic NM-containing neurons by laser capture microdissection from male and female wild-type and tgNM animals at 3 months, 12 months and 20 months of age (n=4-6 mice per group). We performed differential expression analysis, resulting in statistically significant differentially expressed genes at all ages (p-value<0.5). Gene-set enrichment analysis (GSEA) with Reactome Pathway Database led to the identification of altered biological pathways in tgNM related to neuroinflammation, vesicle-mediated transport and lipid metabolism, transcription and translation, mitochondrial function and cell cycle (senescence) (False Discovery Rate<0.05). Targeted-based validation of candidate RNA species was performed in microdissected samples by quantitative real-time PCR and candidate biological pathways were validated at the protein level by western blot in dissected ventral midbrain tissues from biological replicates. The transcriptomic profiles identified in this project contribute to our understanding of selective vulnerability in PD and brain aging, and points to key biological pathways and molecular targets in prodromal and early PD

Pyramidal Neurons in Rat Prefrontal Cortex Projecting to Ventral Tegmental Area and Dorsal Raphe Nucleus Express 5-HT2A Receptors

The prefrontal cortex (PFC) is involved in higher brain functions altered in schizophrenia. Classical antipsychotics modulate cortico-limbic circuits mainly through subcortical D2 receptor blockade, whereas second generation (atypical) antipsychotics preferentially target cortical 5-HT receptors. Anatomical and functional evidence supports a PFC-based control of the brainstem monoaminergic nuclei. Using a combination of retrograde tracing experiments and in situ hybridization we report that a substantial proportion of PFC pyramidal neurons projecting to the dorsal raphe (DR) and/or ventral tegmental area (VTA) express 5-HT2A receptors. Cholera-toxin B application into the DR and the VTA retrogradely labeled projection neurons in the medial PFC (mPFC) and in orbitofrontal cortex (OFC). In situ hybridization of 5-HT2A receptor mRNA in the same tissue sections labeled a large neuronal population in mPFC and OFC. The percentage of DR-projecting neurons expressing 5-HT2A receptor mRNA was ∼60% in mPFC and ∼75% in OFC (n = 3). Equivalent values for VTA-projecting neurons were ∼55% in both mPFC and ventral OFC. Thus, 5-HT2A receptor activation/blockade in PFC may have downstream effects on dopaminergic and serotonergic systems via direct descending pathways. Atypical antipsychotics may distally modulate monoaminergic cells through PFC 5-HT2A receptor blockade, presumably decreasing the activity of neurons receiving direct cortical inputs

Intraspecific crosses resulting in the first occurrence of eight and nine B chromosomes in Prochilodus lineatus (Characiformes, Prochilodontidae)

B chromosomes are supernumerary elements present in about 15% of eukaryotic species and are most frequently heterochromatic, behave parasitically, show a transmission rate higher than standard (A) chromosomes, and can provoke harmful effects on carriers. In the current work, Prochilodus lineatus individuals carrying eight and nine B chromosomes were obtained by induced crossing performed involving breeders with different B chromosome numbers in their cells. The high B chromosome numbers found in the offspring were recorded for the first time in this species. The use of cytogenetic techniques applied in the present study revealed that regardless of the increase in number of B chromosomes in the genome of these individuals, those elements did not presented active genes, and showed their normal heterochromatic characteristic