Alterações cognitivas na infecção pelo HIV: uma revisão sistemática: Cognitive changes in HIV infection: a systematic review

Provocada pelo vírus da imunodeficiência humana, com a síndrome da imunodeficiência adquirida, numa pessoa tem o seu sistema imunológico prejudicado, tornando-se suscetível a outras doenças e infecção. Tem-se a estimativa de que 50% dos infectados com o referido vírus podem sofrer alterações cognitivas. Diante disso, este estudo tem como objetivo refletir sobre mudanças estruturais cerebrais e comprometimento cognitivo em pacientes com HIV. Portanto, trata-se de uma revisão sistemática de literatura, desenvolvida a partir da seleção de estudos nas bases de dados Scielo, Pubmed e BVS/Medline a partir do uso de descritores DeCS/MeSH e aplicação de critérios de inclusão e exclusão. Após a análise e interpretação dos dados, concluiu-se que há uma significativa prevalência de HAND em adultos infectados por HIV, no que se refere a alterações cognitivas, especialmente entre pacientes do sexo feminino, de baixa escolaridade e renda, com diagnóstico tardio e baixa quantidade de linfócitos CD4 no início do tratamento. Entre essas pessoas, revelam-se comprometimentos quanto à memória, atenção, controle de impulsos, velocidade de processamento e motora, dentre outros

ATLANTIC EPIPHYTES: a data set of vascular and non-vascular epiphyte plants and lichens from the Atlantic Forest

Epiphytes are hyper-diverse and one of the frequently undervalued life forms in plant surveys and biodiversity inventories. Epiphytes of the Atlantic Forest, one of the most endangered ecosystems in the world, have high endemism and radiated recently in the Pliocene. We aimed to (1) compile an extensive Atlantic Forest data set on vascular, non-vascular plants (including hemiepiphytes), and lichen epiphyte species occurrence and abundance; (2) describe the epiphyte distribution in the Atlantic Forest, in order to indicate future sampling efforts. Our work presents the first epiphyte data set with information on abundance and occurrence of epiphyte phorophyte species. All data compiled here come from three main sources provided by the authors: published sources (comprising peer-reviewed articles, books, and theses), unpublished data, and herbarium data. We compiled a data set composed of 2,095 species, from 89,270 holo/hemiepiphyte records, in the Atlantic Forest of Brazil, Argentina, Paraguay, and Uruguay, recorded from 1824 to early 2018. Most of the records were from qualitative data (occurrence only, 88%), well distributed throughout the Atlantic Forest. For quantitative records, the most common sampling method was individual trees (71%), followed by plot sampling (19%), and transect sampling (10%). Angiosperms (81%) were the most frequently registered group, and Bromeliaceae and Orchidaceae were the families with the greatest number of records (27,272 and 21,945, respectively). Ferns and Lycophytes presented fewer records than Angiosperms, and Polypodiaceae were the most recorded family, and more concentrated in the Southern and Southeastern regions. Data on non-vascular plants and lichens were scarce, with a few disjunct records concentrated in the Northeastern region of the Atlantic Forest. For all non-vascular plant records, Lejeuneaceae, a family of liverworts, was the most recorded family. We hope that our effort to organize scattered epiphyte data help advance the knowledge of epiphyte ecology, as well as our understanding of macroecological and biogeographical patterns in the Atlantic Forest. No copyright restrictions are associated with the data set. Please cite this Ecology Data Paper if the data are used in publication and teaching events. © 2019 The Authors. Ecology © 2019 The Ecological Society of Americ

Humic substances and their effects on soil chemical and biological attributes and plant production

A matéria orgânica do solo (MOS) é composta de uma mistura complexa e heterogênea de compostos orgânicos, sendo as substâncias húmicas (SH) a fração mais recalcitrante da MOS. As SH têm grande influência sobre as propriedades químicas e biológicas do solo, contribuindo como fonte de energia para microrganismos e também contribuindo com a disponibilidade de nutrientes. Além disso, as SH podem contribuir de forma expressiva para o desenvolvimento e produção das plantas cultivadas. Neste sentido, o objetivo deste trabalho foi avaliar a atividade e diversidade da comunidade bacteriana do solo, a disponibilidade de nutrientes e a produtividade da cultura de trigo após aplicação de doses crescentes de SH. Dois experimentos foram montados e avaliados, sendo um ensaio de incubação com um solo arenoso e outro um experimento de casa de vegetação com plantas de trigo em dois solos tropicais distintos (textura arenosa e argilosa). Houve um estímulo à atividade microbiana em ambos os experimentos, sendo este estímulo transitório, o que provavelmente ocorreu devido a um efeito priming provocado pela adição de SH. No entanto não houve alteração na estrutura da comunidade bacteriana pela adição de SH, o que pode ser devido ao fato de ser um material recalcitrante e já presente no solo. Também houve aumento na disponibilidade de fósforo, potássio, cálcio e nitrogênio, bem como da CTC, tanto em solo arenoso quanto argiloso, expressando o efeito das SH na melhoria das propriedades químicas de solos tropicais. Além disso, um efeito significativo foi visto em parâmetros relacionados à produtividade do trigo. Houve aumento de massa seca de raízes e parte aérea, além de aumento no peso e número de grãos, o que pode se refletir em aumento considerável de produtividade. Esses resultados são importantes por mostrarem que mesmo a fração mais recalcitrante da MOS pode influenciar positivamente aspectos químicos e biológicos do solo, contribuindo com a melhoria do sistema de produção e também com maiores produtividades vegetais.The soil organic matter (SOM) is composed of a complex and heterogeneous mixture of organic compounds, in which the humic substances (HS) are considered to be the most recalcitrant fraction. HS have great influence on chemical and biological soil properties, contributing as energy source for microorganisms and as nutrient reservoir for plants. Furthermore, HS can contribute significantly to the development and production of crop plants. Therefore, the objective of this study was to evaluate the activity and diversity of the soil bacterial community, nutrient availability and productivity of a wheat crop after application of increasing doses of HS. For this purpose, two experiments were performed and evaluated, one is an incubation essay with a sandy soil and the other a greenhouse experiment with wheat plants using two distinct tropical soils as substrates (sandy and clayey). Microbial activity was stimulated in both experiments, and this transient stimulus may have been due to a priming effect caused by the addition of HS. However, there was no change in the bacterial community structure which may be due to the fact that HS is a recalcitrant material and already present in the soil. Nevertheless, we found an increase in the availability of phosphorus, potassium, calcium and nitrogen, as well as in the CEC in both, sandy and clayey soils, showing that HS do improve chemical properties of tropical soils. Furthermore, we found a significant effect on wheat productivity related parameters. There was an increase of dry weight of roots and shoots, as well as increased weight and number of grains, which may be reflected in a significant increase in productivity. These results are important because they show that even the most recalcitrant SOM fraction can positively influence soil chemical and biological aspects, contributing to the improvement of the production system and also to higher plant productivity

Reclamation status of a degraded pasture based on soil health indicators

Pasture degradation is a concern, especially in susceptible sandy soils for which strategies to recover them must be developed. Microbiological and biochemical soil health indicators are useful in the guindace of soil management practices and sustainable soil use. We assessed the success of threePanicum maximum Jacq. cultivars in the reclamation of a pasture in a sandy Typic Acrudox in the northwest of the state of Paraná, Brazil, based on soil health indicators. On a formerly degraded pasture withUrochloa brizantha (Hochst. ex A. Rich.) R.D. Webster, a trial with threeP. maximum (cv. Massai, Tanzânia, or Mombaça) was conducted. Lime and phosphate were applied at set-up, and mineral N and K as topdressing. A remnant of degraded pasture adjacent to the trial was used as control. Twenty-three chemical, physical, microbiological and biochemical attributes were assessed for the 0-10 cm topsoil. The procedures for reclamation improved most of the indicators of soil health in relation to the degraded pasture, such as soil P, mineral N, microbial biomass C, ammonification rate, dehydrogenase activity and acid phosphatase. CO2 evolution decreased, whereas microbial biomass C increased in the pasture under reclamation, resulting in a lower metabolic quotient (qCO2) that points to a decrease in metabolic stress of the microbial community. The reclamation of the pasture withP. maximum, especially cv. Mombaça, were evidenced by improvements in the microbiological and biochemical soil health indicators, showing a recovery of processes related to C, N and P cycling in the soil

Eucalyptus grandis and Acacia mangium in monoculture and intercropped plantations: Evolution of soil and litter microbial and chemical attributes during early stages of plant development

Soil microorganisms and microbial processes are influenced by the quality and quantity of plant waste entering the soil, by its seasonal and spatial distribution, by the ratio of above- to below-ground inputs, and by changes in nutrient inputs. Soil management strategies sometimes promote mixed-species plantations to mitigate the loss of soil nutrients and improve biogeochemical cycling. The objective of this study was to explore changes in microbiological and chemical attributes of soils and litter in the early stages of the second rotation of mixed and pure plantations of Eucalyptus grandis and Acacia mangium, and to look for correlations between attributes. Soil samples at 0-10 cm depth were collected two, seven, 14, and 20 months after planting in the following treatments: monocultures of A. mangium and E. grandis, a monoculture of E. grandis with N-fertilizer, and an intercropped plantation with E. grandis and A. mangium. Microbial soil attributes varied dramatically between treatments 20 months after planting. Total C, N and P contents in litter showed the strongest correlations with microbial biomass C and N (C-mic and N-mic), microbial respiration, and dehydrogenase activity in all sampling periods. Lower C/N and C/P ratios in litter and lower C/N and C-mic/tC ratios in soils after 20 months in the intercropped plantation illustrated the system's capacity for supplying inputs of high-quality organic matter rich in N and P, but this did not result in higher contents of these elements or greater microbial activity in soils. An implication of this finding is that, at least in the initial growth phase of these plantations, chemical attributes of the litter and variation in those attributes govern microbial processes and, consequently, are mostly responsible for plant development. Canonical discriminant analysis revealed changes in the microbiological and chemical attributes of soil in the intercropped plantation due to the plants growth and the leaf litter accumulation. Twenty months after planting, the different plantations could be discriminated by differences in litter chemistry (C, N, and P), total soil C, N-mic, and dehydrogenase activity, which were very similar in intercropped plantations and E. grandis with N-fertilizer. These results from the early stages of plantation development are important for understanding the dynamics of soil attributes in these systems, and especially in intercropped plantations. In intercropped areas the cumulative effect of microbial attributes reflects a more sustainable system. Long-term studies are needed to identify patterns that develop after 20 months, during the growth period of these plantation

Intercropping Acacia mangium stimulates AMF colonization and soil phosphatase activity in Eucalyptus grandis

ABSTRACT: Arbuscular mycorrhizal fungi (AMF) are very important to plant nutrition, mostly in terms of acquisition of P and micronutrients. While Acacia mangium is closely associated with AMF throughout the whole cycle, Eucalyptus grandis presents this symbiosis primarily at the seedling stage. The aim of this study was to evaluate the dynamics of AMF in these two tree species in both pure and mixed plantations during the first 20 months after planting. We evaluated the abundance, richness and diversity of AMF spores, the rate of AMF mycorrhizal root colonization, enzymatic activity and soil and litter C, N and P. There was an increase in AMF root colonization of E. grandis when intercropped with A. mangium as well as an increase in the activity of acid and alkaline phosphatase in the presence of leguminous trees. AMF colonization and phosphatase activities were both involved in improvements in P cycling and P nutrition in soil. In addition, P cycling was favored in the intercropped plantation, which showed negative correlation with litter C/N and C/P ratios and positive correlation with soil acid phosphatase activity and soil N and P concentrations. Intercropping A. mangium and E. grandis maximized AMF root colonization of E. grandis and phosphatase activity in the soil, both of which accelerate P cycling and forest performance

Intercropping Acacia mangium stimulates AMF colonization and soil phosphatase activity in Eucalyptus grandis

<div><p>ABSTRACT: Arbuscular mycorrhizal fungi (AMF) are very important to plant nutrition, mostly in terms of acquisition of P and micronutrients. While Acacia mangium is closely associated with AMF throughout the whole cycle, Eucalyptus grandis presents this symbiosis primarily at the seedling stage. The aim of this study was to evaluate the dynamics of AMF in these two tree species in both pure and mixed plantations during the first 20 months after planting. We evaluated the abundance, richness and diversity of AMF spores, the rate of AMF mycorrhizal root colonization, enzymatic activity and soil and litter C, N and P. There was an increase in AMF root colonization of E. grandis when intercropped with A. mangium as well as an increase in the activity of acid and alkaline phosphatase in the presence of leguminous trees. AMF colonization and phosphatase activities were both involved in improvements in P cycling and P nutrition in soil. In addition, P cycling was favored in the intercropped plantation, which showed negative correlation with litter C/N and C/P ratios and positive correlation with soil acid phosphatase activity and soil N and P concentrations. Intercropping A. mangium and E. grandis maximized AMF root colonization of E. grandis and phosphatase activity in the soil, both of which accelerate P cycling and forest performance.</p></div