Percepção ambiental dos moradores de São José do Goaibal sobre o parque estadual do Rio Doce:A influência das variáveis gênero, idade, classe social e escolaridade

O Parque Estadual do Rio Doce (PERD) foi a primeira unidade de conservação criada em Minas Gerais e é uma das maiores áreas remanescentes de Mata Atlântica no país. O objetivo deste estudo foi investigar em São José do Goiabal, município circunvizinho ao parque, a percepção dos moradores sobre o PERD analisando, através de entrevistas semi-estruturadas, a influência de diferentes variáveis. Os dados mostraram que gênero, classe social e idade não determinam a frequência de visitação. A caça a animais silvestres mostrou-se como prática comum, reconhecida pela população e motivada principalmente pelo lazer e apreciação da carne. O desenvolvimento de projetos de Educação Ambiental envolvendo alunos da rede básica de educação é o fator que mais influencia no conhecimento e valorização do PERD. Tais constatações sugerem a necessidade da implantação de programas de educação ambiental voltados principalmente para crianças e jovens, tornando-os parceiros dos propósitos de conservação da biodiversidade na região

Colonization of Brasilonema octagenarum UFV-E1 (Cyanobacteria) in young plants of eucalyptus and the identification of bioactive substances

As cianobactérias produzem uma grande diversidade de compostos biológicos de interesse econômico-industrial, referidos genericamente como "substâncias bioativas", uma expressão ampla que inclui substâncias capazes de, em baixas concentrações, afetar processos metabólicos vitais de outros organismos. Recentemente, uma nova espécie de cianobactéria, Brasilonema octagenarum UFV-E1 foi identificada, em viveiro de produção de mudas clonais, formando um biofilme denso sobre a parte aérea de plantas jovens de Eucalyptus spp. O objetivo deste trabalho foi investigar as conseqüências da colonização por B. octagenarum sobre plantas jovens de Eucalyptus urograndis, sendo analisados aspectos morfológicos, bioquímicos, e de crescimento. Os experimentos foram realizados sob condições de umidade e temperatura controladas. Suspensão celular de B. octagenarum foi aplicada sobre a parte aérea de plantas jovens e o controle consistiu de plantas não inoculadas. Decorridos trinta dias após a inoculação, observou-se a formação de colônias dispersas sobre o limbo foliar. Nas áreas colonizadas, houve diminuição na relação clorofila a / b em 19% em relação ao controle. Não houve diferença significativa no conteúdo dos pigmentos (clorofila a, b e carotenos). Dentre os parâmetros biométricos avaliados (massa seca de folhas, caule e raiz, área foliar e altura do caule) ficou evidente o aumento de massa seca de raiz e de caule em relação ao controle (19 e 23%, respectivamente). Não foram observadas alterações anatômicas, ou a produção de compostos fenólicos totais. B. octagenarum colonizou as folhas das plantas, numa relação de epifitismo, sem ocasionar efeitos prejudiciais, durante o período de avaliação deste estudo, em que foram observados os estágios iniciais da colonização. As plantas responderam positivamente à colonização, com maior produção de massa seca, principalmente de caule e de raiz. Diante deste estímulo no crescimento, semelhante ao tratamento com auxinas, investigou-se a produção de substâncias bioativas por B. octagenarum, através de bioensaio e a influência da colonização por esta espécie de cianobactéria no enraizamento de mini-estacas de E. urophylla e E. urograndis. O extrato de células de B. octagenarum foi analisado em cromatógrafo líquido acoplado em espectrômetro de massa, LC-MS/MS. Mini-estacas de E. urophylla e E. urograndis foram inoculadas com suspensão celular de B. octagenarum. Houve aumento de massa seca de raízes, em 31% e de caule (44%) na espécie E. urophylla. Através da análise em LC-MS/MS, identificou-se o ácido indol acético (AIA), com 175 Da. A colonização por B. octagenarum em Eucalyptus urograndis, sob as condições adotadas neste estudo, estimulou o crescimento das plantas, possivelmente, em resposta à produção do AIA. Foi demonstrado que B. octagenarum produz a auxina ácido indol acético e que essa cianobactéria possui potencial para ser utilizada no desenvolvimento de técnicas de propagação vegetativa em culturas de eucalipto.Cyanobacteria produces a wide variety of biological compounds of economic-industrial interest, often referred to as "bioactive molecules". This is a broad term that include substances, which at low concentrations, are able to affect vital metabolic processes. Recently, a new species of cyanobacteria, Brasilonema octagenarum UFV-E1, was identified. The cyanobacteria was found forming a dense biofilm covering the aerial parts of young plants of Eucalyptus spp on a clonal plant nursery. The aim of this study was to investigate the consequences of B. octagenarum colonization, on morphological, biochemical, and growth traits of young plants of Eucalyptus urograndis. The experiments were carried out under humidity and temperature controlled conditions. A cellular suspension of B. octagenarum was applied over the aerial parts of young plants. The control group consisted of non inoculated plants. Thirty days after the inoculation, the formation of scattered colonies over the leaf was observed. There was a decrease of 19% in the chlorophyll a / b ratio in the leaf areas beneath the colonies. There was no significant difference in the content of pigments (chlorophyll a, b and carotenoids). The plants responded positively to the colonization, with increase of dry mass production, mainly of the stem and root. The increase of the root and stem dry mass of colonized plants were significantly higher compared to the control group (19 and 23%, respectively). Neither anatomic alterations nor an increase in the production of total phenolic compounds were observed. During the duration period of the experiment, which compromised the initial stages of colonization, B. octagenarum colonized the aerial part of the plant without damaging it, establishing an epiphytism relation. The effects of bioactive compounds by B. octagenarum, as stimuli to plant growth, such auxin, was tested by means of a bioassay, and the influence of this cyanobacteria species colonization on rooting process of E. urophylla and E. urograndis mini-cuttings was investigated. The extract of B. octagenarum cells was analyzed in liquid chromatography coupled to mass spectrometer, LC-MS/MS. Mini-cuttings of E. urophylla and E. urograndis were inoculated with a concentrated solution of B. octagenarum cells. There was a significant increase in dry mass in the roots (31%), and in the stem (44%) in the E. urophylla. Throught the LC-MS/MS analyses, indol acetic acid (IAA) was identified, has 175 Da. The colonization of B. octagenarum in Eucalyptus urograndis, under the conditions of this study, stimulated the growth of plants, possibly in response to the IAA production. It was demonstrated that B. octagenarum produces the auxin indol acetic acid, and that this cyanobacteria has the potential to be used in developing techniques of vegetative propagation of eucalyptus plants.Conselho Nacional de Desenvolvimento Científico e Tecnológic

Arsenic tolerance of Microcystis novacekii (Komárek-Compère, 1974) and its arsenic decontamination potential

ABSTRACT Cyanobacteria possess metallic ion interaction properties that should be explored with the aim of recovering arsenic (As) contaminated areas. Contamination of As is an issue of worldwide concern due to the risk of human chronic intoxication and negative environmental health effects. In this study the potential decontamination of As(III) and As(V) using cyanobacteria cultures was assessed. Microcystis novacekii (Komárek-Compere, 1974) showed normal growth in concentrations of As(V) similar to those found in natural environments contaminated with As, demonstrating its resistance to As(V). Growth rates gradually decreased upon exposure to high As(V) concentrations from 600 to 5630 mg.L-1 while As(III) affected growth from 14.7 - 85.7 mg.L-1. The As(III) EC50 value (41.0 mg.L-1) was 140-fold lower possibly due to differences in As(III) and As(V) absorption pathways. Upon exposure to 14.7 mg.L-1 As(III), 21.2% of As was removed from culture medium. The absorption capacity (12000 mg.kg-1) remained constant with increasing As(III) concentrations in a dose independent effect. The potential of M. novacekii for As decontamination was demonstrated in this study. This microorganism is recommended in As bioremoval studies due to its autotrophic-mixotrophic growth, low nutritional requirements and high As(III) absorption capacity

A NOVEL EPIPHYTIC CYANOBACTERIAL SPECIES FROM THE GENUS BRASILONEMA CAUSING DAMAGE TO EUCALYPTUS LEAVES

A cyanobacterial mat colonizing the leaves of Eucalyptus grandis was determined to be responsible for serious damage affecting the growth and development of whole plants under the clonal hybrid nursery conditions. The dominant cyanobacterial species was isolated in BG-11 medium lacking a source of combined nitrogen and identified by cell morphology characters and molecular phylogenetic analysis (16S rRNA gene and cpcBA-IGS sequences). The isolated strain represents a novel species of the genus Brasilonema and is designated Brasilonema octagenarum strain UFV-E1. Thin sections of E. grandis leaves analyzed by light and electron microscopy showed that the B. octagenarum UFV-E1 filaments penetrate into the leaf mesophyll. The depth of infection and the mechanism by which the cyanobacterium invades leaf tissue were not determined. A major consequence of colonization by this cyanobacterium is a reduction in photosynthesis in the host since the cyanobacterial mats decrease the amount of light incident on leaf surfaces. Moreover, the cyanobacteria also interfere with stomatal gas exchange, decreasing CO2 assimilation. To our knowledge, this is the first report of an epiphytic cyanobacterial species causing damage to E. grandis leaves.Fundacao de Amparo a Pesquisa do Estado de Minas Gerais (FAPEMIG)[CRA/2004]Federal University of Vicosa (UFV)CNPqCAPESFundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[2005/56303-5]CNPq (National Council for Scientific and Technological Development)[140327/2004-5

Physiological and thylakoid ultrastructural changes in cyanobacteria in response to toxic manganese concentrations

In this study, two cyanobacterial strains (morphologically identified as Microcystis novacekii BA005 and Nostoc paludosum BA033) were exposed to different Mn concentrations: 7.0, 10.5, 15.7, 23.6 and 35.4 mg L−1 for BA005; and 15.0, 22.5, 33.7, 50.6, and 76.0 mg L−1 for BA033. Manganese toxicity was assessed by growth rate inhibition (EC50), chlorophyll a content, quantification of Mn accumulation in biomass and monitoring morphological and ultrastructural effects. The Mn EC50 values were 16 mg L−1 for BA005 and 39 mg L−1 for BA033, respectively. Reduction of chlorophyll a contents and ultrastructural changes were observed in cells exposed to Mn concentrations greater than 23.6 and 33.7 mg L−1 for BA005 and BA033. Damage to intrathylakoid spaces, increased amounts of polyphosphate granules and an increased number of carboxysomes were observed in both strains. In the context of the potential application of these strains in bioremediation approaches, BA005 was able to remove Mn almost completely from aqueous medium after 96 h exposure to an initial concentration of 10.5 mg L−1, and BA033 was capable of removing 38% when exposed to initial Mn concentration of 22.5 mg L−1. Our data shed light on how these cyanobacterial strains respond to Mn stress, as well as supporting their utility as organisms for monitoring Mn toxicity in industrial wastes and potential bioremediation application

Determination of methylmercury in sediment and cyanobacteria samples : method validation and application to methylation investigation.

The aim of this work was to validate two methods for methylmercury (CH3Hg+) determination in sediments and cyanobacteria and their application to the Hg methylation study of planktonic organisms in water from a contaminated site in Brazil. Analytical methods for the determination of CH3Hg+ include many steps, and the necessity of adaptation to different matrices is very common and not always easy. In addition, these adaptations require new optimization and validation, which are found in a few articles using the matrix sediments but in none with planktonic organisms. The methods presented here were based on the extraction of CH3Hg+ from these matrices, derivatization, trapping, thermal desorption, GC separation, pyrolysis and detection by AFS (GC-pyro-AFS). The results showed good linearity (0.994) in the range of 0 to 400 pg CH3Hg+ with a repeatability of 3%, an intermediate precision of 8%, a recovery in spiked sample tests in the range of 93 to 129%, and detection limits of 0.04 mg kg 1 for sediments and 1.3 mg kg 1 for cyanobacteria. Certified reference materials showed good recoveries. The method for the cyanobacteria matrix was used for the Hg2+ methylation assay with cultures of cyanobacteria and microalgae isolated from water samples collected in an ancient Hg-contaminated gold mining area in Brazil. The production of CH3Hg+ was detected only in the culture of the microalga Stichococcus species (0.23% of total Hg), indicating its participation in the biotransformation of Hg. The methods can be used as important tools in routine analysis and/or studies of the biogeochemical cycle of Hg

Algistatic effect of a quinonamethide triterpene on Microcystis novacekii.

Cyanobacteria proliferation represents a problem to water treatment for human consumption supply. Species of the genus Microcystis, commonly found in continental waters, can bloom and produce microcystine and other toxic compounds associated to human and animal poisoning, depending on the nutrient levels present in the water. The use of natural products to control cyanobacteria blooms is promising since they are less harmful to the environment than compounds obtained by organic syntheses. Triterpenes, which are associated with several biological activities, have been isolated from species of the genus Maytenus (Celastraceae), commonly found in Cerrado regions of Brazil. Tingenone is a pentacyclic triterpene that has cytotoxic properties and induces growth inhibition in some microorganisms. In this study, the effects of tingenone isolated from Maytenus gonoclada at distinct concentrations (e.g., 50, 150, 500, 1,500, and 4,500 μg L−1) on the growth rates of Microcystis novacekii was investigated. The algicide activity was verified using M. novacekii cultures growing in ASM1 culture medium at 23 °C and continuous illumination for 96 h. Growth inhibition was monitored by light microscopy and optical density (OD680 nm). The median effective concentration associated to the M. novacekii inhibition growth induced by tingenone was 12.2 μg L−1. The result indicates that tingenone has algicide effect and can be potentially applied in water management for public supply, replacing synthetic algicides