Genetics of Parkinson´s disease: Recessive forms

The genes associated with autosomal recessive Parkinson's disease (PD) include the PRKN, PINK1, and DJ-1 genes. Homozygous and compound heterozygous carriers of pathogenic variants of these genes tend to display typical characteristics of PD at early ages.On the other hand, the ATP13A2, FBXO7, PLA2G6, SYNJ1, and DNAJC6 genes are associated with early-onset recessive forms that frequently present with pyramidal signs, ataxia, and oculomotor alterations, with early appearance of levodopa-induced motor fluctuations and dyskinesia. Such non-motor symptoms as depression, psychiatric disorders, hallucinations, and epilepsy are also more frequent in this group.Among multiple molecular mechanisms involved in these cases, key examples are the dysfunction of mitochondrial and lysosomal processes.This article presents a brief review intended to inform clinicians about the basic molecular mechanisms and phenotype–genotype relationship of these monogenic forms of PD. Resumen: Los genes asociados a enfermedad de Parkinson (EP) de herencia mendeliana autosómica recesiva incluyen PRKN, PINK1 y DJ-1. Los individuos portadores homocigotos o heterocigotos compuestos de variantes patogénicas en estos genes tienden a manifestar características típicas de la enfermedad de EP a edad temprana.Por otro lado, los genes ATP13A2, FBXO7, PLA2G6, SYNJ1, y DNAJC6, se asocian a formas recesivas de manifestación precoz, presentan con frecuencia signos piramidales, ataxia y alteraciones oculomotoras, y desarrollan tempranamente, fluctuaciones motoras y disquinesias inducidas por levodopa. Alteraciones no motoras como depresión, alteraciones psiquiátricas, alucinaciones y epilepsia son también más frecuentes en este grupo.Entre los múltiples aspectos moleculares comprometidos en estos casos, destacan la disfunción de procesos mitocondriales y lisosomales.En este artículo presentamos una breve revisión orientada al clínico sobre los aspectos moleculares básicos y relación fenotipo-genotipo de estas formas monogénicas de la EP

Changes in agricultural management drive the diversity of Burkholderia species isolated from soil on PCAT medium

In order to assess the diversity of culturable Burkholderia populations in rhizosphere and bulk soil and to evaluate how different agricultural management regimes and land use history affect this diversity, four treatments were evaluated: permanent grassland; grassland converted into maize monoculture; arable land and arable land converted into grassland. Burkholderia isolates obtained on PCAT medium were grouped in 47 clusters using 16S ribosomal RNA gene based PCR-DGGE combined with BOX genomic fingerprinting (DGGE-BOX). The distribution of the isolates in the DGGE-BOX clusters was used to calculate the Shannon diversity index per treatment. Interestingly, we observed that the Burkholderia diversity was affected by changes in the agricultural management, since the highest diversity was observed in permanent grassland and in continuous arable land. In addition, the diversity tended to be higher in the rhizosphere than in the corresponding bulk soil. The use of species abundance models indicated that rhizosphere communities had more even distributions than communities collected from the bulk soil. Identification of isolates revealed that only 2% of these belonged to the B. cepacia complex and that the majority was assigned to either (1) new Burkholderia species or (2) Burkholderia species that had originally been isolated from soil. Isolates classified as B. hospita, B. caledonica and Burkholderia sp. LMG 22934' and `LMG 22936' were found mainly in the arable land, while isolates belonging to Burkholderia sp. `LMG 22929 and B. phytofirmans were associated with the grassland area. Another potentially new Burkholderia species, `LMG 22932'', was found in both areas, in close association with the maize rhizospher

Análise da variabilidade genética aditiva de características de crescimento na raça Nelore Additive genetic variability analysis in the growth characteristics of Nellore breed

Foram utilizados dados de cinqüenta e um rebanhos participantes do Programa de Melhoramento Genético da Raça Nelore (PMGRN), distribuídos nos estados de Goiás (GO), Mato Grosso do Sul (MS), Mato Grosso (MT), Minas Gerais (MG), São Paulo (SP), Maranhão (MA) e Bahia (BA). Foram obtidas estimativas de parâmetros genéticos para os pesos padronizados aos 120 (P120), 455 (P455) e 550 (P550) dias de idade. Análises unicaráter e bicaráter foram realizadas por modelo animal usando o aplicativo MTDFREML. Para P120 foi utilizado um modelo que incluiu como efeitos fixos, grupo de contemporâneos e classe de idade da vaca ao parto, e como aleatórios, os efeitos genéticos direto, materno e de ambiente permanente da vaca. Para P455 e P550, o modelo utilizado incluiu os mesmos efeitos fixos e o efeito genético direto do animal. ANas análises unicaráter, as estimativas de herdabilidade direta foram 0,29, 0,51 e 0,47 para P120, P455 e P550, respectivamente. Nas análises bicaráter, observaram-se coeficientes de herdabilidade direta de 0,50 e 0,58 para P120, 0,50 e 0,53 para P455 e 0,44 e 0,49 para P550. As correlações genéticas estimadas entre P120 e P455, P120 e P550 e P455 e P550, foram 0,92, 0,93 e 0,96, respectivamente. As estimativas de herdabilidade obtidas para P455 e as correlações genéticas deste peso com P120 e P550 sugerem que a avaliação genética pode ser feita aos 15 meses de idade em substituição aos 18 meses.<br>The data were obtained from 51 herds to participate in the Nelore Catttle Breeding Program (NCBP) from the states of Goiás (GO), Mato Grosso do Sul (MS), Mato Grosso (MT), Minas Gerais (MG), São Paulo (SP), Maranhão (MA) and Bahia (BA). Were used to estimative genetic parameters for standardized weights at 120 (P120), 455 (P455) and 550 (550) days of age. Univariate and bivariate analysis were performed by animal model using MTDFREML program. For P120 was used a model that included contemporary groups and cow age at calving as fixed effects, and direct genetic, maternal genetic and permanent environment effects as random effects. For P455 and P550 were utilized the same model but without maternal direct and permanent environment effects. The estimates of heritability direct from univariate analysis were: 0.29, 0.51 and 0.47 for P120, P455 and P550, respectively. In the bivariate analyses the direct heritability values were of high magnitude. The genetic correlation between P120 and P455, P120 and P550 and P455 and P550 were 0.92, 0.93 and 0.96, respectively. The values of the heritability coefficients estimated for the trait P455 and genetic correlation that characteristic with others indicate that the genetic evaluation could be made at the 15 months of age