RÉSUMÉ
We present herein the occurrence and distribution of the heterotrophic straminipiles collected from soil and water, submerged leaves and surface sediment from freshwater bodies at "Mosaico de Unidades de Conservação Juréia-Itatins", a preserved conservation unit of the Brazilian Atlantic Rainforest. From 180 collected samples, we isolated 41 taxa belonging to Hyphochytriomycota and Oomycota using the multiple baiting technique, with several new taxa to the science, new occurrences to São Paulo State or Brazil, and all new citation to the studied area. These taxa were identified based on morphological and/or molecular data, with several genic regions made available in GenBank. The calculated community structure of these zoosporic organisms showed a diverse community, with few dominant taxa, without significant differences (P≤0.05) among the different types of samples.
Apresentamos aqui a ocorrência e a distribuição dos estramenópilos heterotróficos coletados de solo, e de água, folhas submersas e sedimento superficial de corpos de água doce no "Mosaico de Unidades de Conservação Juréia-Itatins", uma unidade de conservação preservada de Mata Atlântica brasileira. Das 180 amostras coletadas, isolamos 41 táxons pertencentes aos filos Hyphochytriomycota e Oomycota, usando a técnica de iscagem múltipla, com vários deles novos táxons para a ciência, novas ocorrências para o estado de São Paulo ou Brasil, e todos primeira ocorrência para o local estudado. Os táxons foram identificados com base em dados morfológicos e/ou moleculares, com várias regiões gênicas disponibilizadas no GenBank. O cálculo da estrutura da comunidade mostrou uma comunidade diversa, com poucos táxons dominantes, sem diferença significativa (P≤0.05) entre os diferentes tipos de amostras.
RÉSUMÉ
A chytrid fungus Olpidium gregarium was found in Rio Grande Reservoir as rotifers populations' parasite. Along the reservoir central axis, the rotifers density decreased in the dam direction, while the density of affected rotifers by the chytrid fungus increased in the same direction. Moreover, some rotifers species were more affected than others, thus showing certain preference for some rotifers species. Thereby, this parasite may be interfering in the distribution of rotifers population in Rio Grande Reservoir. This is the first report of this species for Brazil.
O quitridiomiceto Olpidium gregarium foi encontrado no Reservatório Rio Grande parasitando diversas espécies de rotíferos. Ao longo do eixo central do reservatório, a densidade de rotíferos diminuiu em direção à barragem, enquanto que a abundância relativa de rotíferos afetados pelo quitrídio aumentou na mesma direção. Além disso, algumas espécies de rotíferos foram mais afetadas do que outras, mostrando com isso certa preferência por algumas espécies de rotíferos. Desta forma, este parasita pode estar afetando a distribuição das populações de rotíferos no reservatório. Este é o primeiro relato da espécie no Brasil.
RÉSUMÉ
During a survey of mucoralean fungi from a Cerrado reserve (Brazilian savanna) some isolates of a Mucor-like fungus were isolated from soil plates. Characterization based on morphological, physiological and molecular data from translation elongation factor (EF-1α), 28S (D1/D2) and ITS1-5.8S-ITS2 rDNA sequences was made. The isolates produce lateral branches bearing multispored sporangiola in addition to the multispored sporangia and a uniformly septate mycelium as the main differentiating characteristics. To our surprise this fungus possesses two EF-1α genes 1.4 and 1.5 kb long. Evidence from the analyzed datasets supports the delimitation of a new genus and the inclusion of Mucor fuscus based on 28S and ITS rDNA data.
Sujet(s)
Mucorales/classification , Brésil , ADN ribosomique/analyse , Gènes fongiques , Données de séquences moléculaires , Mucorales/génétique , Mucorales/ultrastructure , Phylogenèse , Analyse de séquence d'ADN , Microbiologie du sol , Spores fongiques/ultrastructureRÉSUMÉ
Zoosporic organisms are commonly found in different aquatic ecosystems; however little is known about the influence of environmental factors and seasonal fluctuations on their occurrence and distribution. This study investigated patterns of abundance, frequency and diversity of these organisms and their relationship with some abiotic factors and seasonality in a cerrado remnant in Sao Paulo, Brazil. Water samples were collected at four dates in two areas of this remnant during the rainy and dry seasons, and 13 abiotic factors were analyzed. From 48 samples collected, 32 taxa were isolated with the multiple baiting technique. The community structure of the zoosporic organisms showed some changes in response to different spatial distribution and seasonal fluctuations, probably influenced by distinct abiotic characteristics of each area or climatic period. Still, the similarity between areas and seasons indicated by Sørensen index and diversity (richness, evenness, Shannon and Simpson indices) were high.
Sujet(s)
Organismes aquatiques/isolement et purification , Écosystème , Eau douce/microbiologie , Eau douce/parasitologie , Organismes aquatiques/classification , Brésil , Climat , Pluie , SaisonsRÉSUMÉ
Estudo da diversidade de quitridiomicetos de solo e água, na "Reserva Biológica de Paranapiacaba", resultou no isolamento de 29 espécies, com três Blastocladiales, 23 Chytridiales, uma Monoblepharidales e duas Spizellomycetales. Dos táxons isolados, 69 por cento são citados pela primeira vez para a Reserva, 14 por cento para o estado de São Paulo, e 7 por cento para o país. É a primeira menção de Rhizophydium condylosum Karling no Brasil.
The diversity study of the chytrids from soil and water from the "Reserva Biológica de Paranapiacaba", yielded 29 species, with three Blastocladiales, 23 Chytridiales, one Monoblepharidales and two Spizellomycetales. From these, 69 percent taxa were cited for the first time for Reserve, 14 percent for São Paulo State and 7 percent for Brazil. Rhizophydium condylosum Karling is being mentioned for the first time in Brazil.