RESUMO
The substrates of the Brazilian campos rupestres, a grassland ecosystem, have extremely low concentrations of phosphorus and nitrogen, imposing restrictions to plant growth. Despite that, this ecosystem harbors almost 15% of the Brazilian plant diversity, raising the question of how plants acquire nutrients in such a harsh environment. Here, we set out to uncover the taxonomic profile, the compositional and functional differences and similarities, and the nutrient turnover potential of microbial communities associated with two plant species of the campos rupestres-dominant family Velloziaceae that grow over distinct substrates (soil and rock). Using amplicon sequencing data, we show that, despite the pronounced composition differentiation, the plant-associated soil and rock communities share a core of highly efficient colonizers that tend to be highly abundant and is enriched in 21 bacterial families. Functional investigation of metagenomes and 522 metagenome-assembled genomes revealed that the microorganisms found associated to plant roots are enriched in genes involved in organic compound intake, and phosphorus and nitrogen turnover. We show that potential for phosphorus transport, mineralization, and solubilization are mostly found within bacterial families of the shared microbiome, such as Xanthobacteraceae and Bryobacteraceae. We also detected the full repertoire of nitrogen cycle-related genes and discovered a lineage of Isosphaeraceae that acquired nitrogen-fixing potential via horizontal gene transfer and might be also involved in nitrification via a metabolic handoff association with Binataceae. We highlight that plant-associated microbial populations in the campos rupestres harbor a genetic repertoire with potential to increase nutrient availability and that the microbiomes of biodiversity hotspots can reveal novel mechanisms of nutrient turnover.
Assuntos
Ecossistema , Microbiota , Brasil , Microbiologia do Solo , Biodiversidade , Bactérias/genética , Bactérias/metabolismo , Plantas/metabolismo , Solo/química , Fósforo/metabolismo , Nitrogênio/metabolismoRESUMO
The rocky, seasonally-dry and nutrient-impoverished soils of the Brazilian campos rupestres impose severe growth-limiting conditions on plants. Species of a dominant plant family, Velloziaceae, are highly specialized to low-nutrient conditions and seasonal water availability of this environment, where phosphorus (P) is the key limiting nutrient. Despite plant-microbe associations playing critical roles in stressful ecosystems, the contribution of these interactions in the campos rupestres remains poorly studied. Here we present the first microbiome data of Velloziaceae spp. thriving in contrasting substrates of campos rupestres. We assessed the microbiomes of Vellozia epidendroides, which occupies shallow patches of soil, and Barbacenia macrantha, growing on exposed rocks. The prokaryotic and fungal profiles were assessed by rRNA barcode sequencing of epiphytic and endophytic compartments of roots, stems, leaves and surrounding soil/rocks. We also generated root and substrate (rock/soil)-associated metagenomes of each plant species. We foresee that these data will contribute to decipher how the microbiome contributes to plant functioning in the campos rupestres, and to unravel new strategies for improved crop productivity in stressful environments.
Assuntos
Magnoliopsida/microbiologia , Microbiota , Fósforo/química , Microbiologia do Solo , Solo/química , Bactérias/classificação , Biodiversidade , Brasil , Fungos/classificação , Metagenoma , Metiltransferases/genética , Análise de Sequência de DNARESUMO
Teschovirus encephalomyelitis is a sporadic disease associated with Teschovirus A (PTV) serotype 1 and, less frequently, other serotypes. In recent years, the number of cases submitted to the Iowa State University Veterinary Diagnostic Laboratory with a history of posterior paresis has increased. Submission histories from various regions of the United States suggest a trend for clinical disease to persist in herds and affect a wider age-range of pigs than historically reported. Polioencephalitis and/or myelitis was consistently present and PTV was detected in affected neural tissue by PCR in a portion of cases. Sequencing from two clinical cases identified PTV-2 and PTV-11. To assess neuropathogenicity of these isolates, 5-week-old cesarean derived and colostrum-deprived pigs were assigned to three groups: negative control (n = 4), PTV-2-inoculated (n = 7), and PTV-11-inoculated (n = 7). Three PTV-2-inoculated pigs developed mild incoordination of the hind limbs, one of which progressed to posterior ataxia. While all PTV-11-inoculated pigs showed severe neurological signs consistent with Teschovirus encephalomyelitis, no evidences of neurological signs were observed in sham-inoculated animals. All PTV-2- and PTV-11-inoculated pigs had microscopic lesions consistent with Teschovirus encephalomyelitis. To our knowledge, this is the first description of PTV-11 and experimental study demonstrating the neuropathogenicity of PTV-11 in the United States.
Assuntos
Encefalomielite/veterinária , Infecções por Picornaviridae/veterinária , Doenças dos Suínos/patologia , Doenças dos Suínos/virologia , Teschovirus/crescimento & desenvolvimento , Experimentação Animal , Animais , Animais Recém-Nascidos , Encéfalo/patologia , Colostro/imunologia , Encefalomielite/patologia , Encefalomielite/virologia , Iowa , Infecções por Picornaviridae/patologia , Infecções por Picornaviridae/virologia , Sorogrupo , SuínosRESUMO
This study evaluates the effect of cashew nut meal (CNM), whole cottonseed (WCS), and calcium salts of long-chain fatty acids (Ca-LCFA) on the fatty acid profiles of meat from hair lambs. Thirty-five 60-d-old, male, noncastrated Santa Ines lambs with an initial average body weight of 13.00 ± 1.80 kg were used in a randomized complete-block design with 7 blocks and 5 treatments. The experimental treatments consisted of a control diet (CON) without supplemental lipids and 4 test diets with different lipid supplements that were selected according to the degree of protection from ruminal hydrogenation and their polyunsaturated fatty acid richness. The tests diets included the following modifications: supplementation with WCS, supplementation with CNM, supplementation with both cottonseed and CNM (CSCNM), and supplementation with Ca-LCFA. The C18:1n9c content was highest in the meat of the animals fed the CNM diet (42.00%). The meat from lambs fed the WCS and Ca-LCFA diets had higher C18:0 contents (25.23 and 22.80%, respectively). The C16:1 content was higher in the meat from the animals fed the CNM and CON diets (1.54 and 1.49%, respectively). C18:2c9t11 concentration was higher in the meat from the animals fed the Ca-LCFA and CNM diets. The estimated enzyme activity of Δ9-desaturase C18 was highest in the muscles of the lambs fed the CON, CNM, and CSCNM diets. The use of cashew nuts in the diet resulted in an increase in the C18:2c9t11 content of the lamb meat, which improved the nutritional characteristics of the fat.
Assuntos
Anacardium/química , Óleo de Sementes de Algodão/química , Ácidos Graxos Insaturados/análise , Nozes/química , Carne Vermelha/análise , Ração Animal/análise , Animais , Peso Corporal , Dieta/veterinária , Análise de Alimentos , Masculino , Músculo Esquelético/química , OvinosRESUMO
Lysine is catabolized via the saccharopine pathway in plants and mammals. In this pathway, lysine is converted to α-aminoadipic-δ-semialdehyde (AASA) by lysine-ketoglutarate reductase/saccharopine dehydrogenase (LKR/SDH); thereafter, AASA is converted to aminoadipic acid (AAA) by α-aminoadipic-δ-semialdehyde dehydrogenase (AASADH). Here, we investigate the occurrence, genomic organization and functional role of lysine catabolic pathways among prokaryotes. Surprisingly, only 27 species of the 1478 analyzed contain the lkr and sdh genes, whereas 323 species contain aasadh orthologs. A sdh-related gene, identified in 159 organisms, was frequently found contiguously to an aasadh gene. This gene, annotated as lysine dehydrogenase (lysdh), encodes LYSDH an enzyme that directly converts lysine to AASA. Pipecolate oxidase (PIPOX) and lysine-6-aminotransferase (LAT), that converts lysine to AASA, were also found associated with aasadh. Interestingly, many lysdh-aasadh-containing organisms live under hyperosmotic stress. To test the role of the lysine-to-AASA pathways in the bacterial stress response, we subjected Silicibacter pomeroyi to salt stress. All but lkr, sdh, lysdh and aasadh were upregulated under salt stress conditions. In addition, lysine-supplemented culture medium increased the growth rate of S. pomeroyi under high-salt conditions and induced high-level expression of the lysdh-aasadh operon. Finally, transformation of Escherichia coli with the S. pomeroyi lysdh-aasadh operon resulted in increased salt tolerance. The transformed E. coli accumulated high levels of the compatible solute pipecolate, which may account for the salt resistance. These findings suggest that the lysine-to-AASA pathways identified in this work may have a broad evolutionary importance in osmotic stress resistance.
Assuntos
Bactérias/genética , Bactérias/metabolismo , Regulação Bacteriana da Expressão Gênica , Lisina/metabolismo , Pressão Osmótica/fisiologia , Bactérias/enzimologia , Escherichia coli/enzimologia , Escherichia coli/genética , Escherichia coli/metabolismo , Genoma Bacteriano/genética , Plantas/genética , Plantas/metabolismoRESUMO
The CO2 evolution of intact potato tubers (Solanum tuberosum, L., var. "Bintje") was analyzed during a 10-day period of their warm (25 +/- 2 degrees C) or cold (5 +/- 1 degrees C) storage, to evaluate cold-stress effects on expression and activities of plant uncoupling mitochondrial protein (PUMP) and alternative oxidase (AOX). CO2 evolution rates were analyzed at 20 degrees C, to reflect their possible capacities. The 20 degrees C CO2 production declined from 13 to 8 mg kg(-1) h(-1) after 2 days of warm storage and then (after 3 to 7 days) decreased from 8 to 6.5 mg kg(-1) h(-1). In contrast, 20 degrees C CO2 evolution did not change after the first day of cold storage, increased up to 14.5 mg kg(-1) h(-1) after 2 days, and decreased to about 12 mg kg(-1) h(-1) after 3 to 7 days of cold storage. Cold storage increased PUMP expression as detected by Western blots and led to elevated capacities of both PUMP (44%) and CN-resistant AOX (10 times), but not the cytochrome pathway. Since we found that cold storage led to about the same mitochondrial respiration of 40 nmol O2 min(-1) mg(-1) attributable to each of the respective proteins, we conclude that both AOX and PUMP equally contribute to adaptation of potato tubers to cold.
Assuntos
Proteínas de Transporte/fisiologia , Respiração Celular/fisiologia , Temperatura Baixa , Proteínas de Membrana/fisiologia , Oxirredutases/fisiologia , Solanum tuberosum/fisiologia , Adaptação Fisiológica , Dióxido de Carbono/análise , Dióxido de Carbono/metabolismo , Proteínas de Transporte/biossíntese , Proteínas de Transporte/genética , Canais Iônicos , Cinética , Proteínas de Membrana/biossíntese , Proteínas de Membrana/genética , Proteínas Mitocondriais , Oxirredutases/biossíntese , Oxirredutases/genética , Proteínas de Plantas , Solanum tuberosum/metabolismo , Temperatura , Transcrição Gênica/fisiologia , Proteína Desacopladora 1 , Regulação para Cima/fisiologiaRESUMO
Temos observado que nos últimos anos a hipnose vem sendo cada vez mais utilizada nos meios científicos e acadêmicos como importante instrumento de estudo e auxílio clínico nas áreas da Medicina, Psicologia e Odontologia. A cada ano o número de artigos publicados na área aumenta visivelmente. Com o avanço tecnológico, a hipnose vem sendo estudada por meio de exames como eletrencefalografia digital, mapeamento cerebral, potenciais evocados, ressonância funcional e tomografia por emissäo de pósitrons. Estes estudos abrem novas perspectivas e outras questões surgem com seus resultados. Por meio de um levantamento bibliográfico de mais de 1100 artigos, desde 1809 até 1999, em lingua inglesa, francesa, espanhola, portuguesa, alemä e holandesa, procuramos separar o que consideramos mais relevante no estudo dos mecanismos neuropsicofisiológicos da hipnose e sua evoluçäo. Diante do que foi exposto podemos concluir: (1) näo existe ainda evidência fisiológica da dissociaçäo entre as funções das áreas heteromodais, áreas unimodais sensitivas e áreas motoras; (2) durante a induçäo praticamente todo hemisfério cerebral esquerdo é ativado, e nas fases de sugestäo, analgesia e alucinaçäo existe visível ativaçäo do giro anterior do cíngulo a direita; (3) alucinar sob hipnose e imaginar em estado de vigília säo eventos que para ocorrerem utilizam circuitos cerebrais distintos; (4) por meio da hipnose podemos alterar consideravelmente funções que envolvem o Sistema Nervoso Autônomo
Assuntos
Giro do Cíngulo , Hipnose , Fenômenos Fisiológicos do Sistema NervosoRESUMO
Temos observado que nos últimos anos a hipnose vem sendo cada vez mais utilizada nos meios científicos e acadêmicos como importante instrumento de estudo e auxílio clínico nas áreas da Medicina, Psicologia e Odontologia. A cada ano o número de artigos publicados na área aumenta visivelmente. Com o avanço tecnológico, a hipnose vem sendo estudada por meio de exames como eletrencefalografia digital, mapeamento cerebral, potenciais evocados, ressonância funcional e tomografia por emissão de pósitrons. Estes estudos abrem novas perspectivas e outras questões surgem com seus resultados. Por meio de um levantamento bibliográfico de mais de 1100 artigos, desde 1809 até 1999, em lingua inglesa, francesa, espanhola, portuguesa, alemã e holandesa, procuramos separar o que consideramos mais relevante no estudo dos mecanismos neuropsicofisiológicos da hipnose e sua evolução. Diante do que foi exposto podemos concluir: (1) não existe ainda evidência fisiológica da dissociação entre as funções das áreas heteromodais, áreas unimodais sensitivas e áreas motoras; (2) durante a indução praticamente todo hemisfério cerebral esquerdo é ativado, e nas fases de sugestão, analgesia e alucinação existe visível ativação do giro anterior do cíngulo a direita; (3) alucinar sob hipnose e imaginar em estado de vigília são eventos que para ocorrerem utilizam circuitos cerebrais distintos; (4) por meio da hipnose podemos alterar consideravelmente funções que envolvem o Sistema Nervoso Autônomo(AU)