Ecological distribution of stream macroalgae in different spatial scales using taxonomic and morphological groups

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Distribution of stream macroalgal communities from the mid-western region of Paraná state, southern Brazil: importance of local scale variation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Macroalgas de ambientes lóticos da região centro-oeste do Paraná, região sul do Brasil

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Macroalgas de riachos da Floresta Nacional de Irati, região centro-sul do Estado do Paraná, Sul do Brasil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Caracterização espectral da água do reservatório de Itupararanga, SP, a partir de imagens hiperespectrais hyperion e análise derivativa

The current accessibility to hyperspectral images of Hyperion/EO1 orbital sensor has brought new perspectives for studies of aquatic environments for allowing the remote estimative of several optically active constituents (OACs) in water body. The changes in the composition and concentration of OACs cause different patterns of absorption and scattering of electromagnetic radiation, likely to be detected using hyperspectral data. Therefore, an investigation was conducted taking into account the spectral characterization of water of a reservoir intended for public supply (Itupararanga Reservoir), from Hyperion/EO1 images and derivative analysis technique applied to spectral curves generated. Simultaneously to the acquisition of a Hyperion/EO1 image, a field campaign was carried out to collect limnological data in situ in georeferenced points. After radiometric correction of the image, reflectance curves of pixels were extracted for each station and the curves obtained were subjected to the technique of derivative analysis, which revealed features of absorption and scattering mainly associated to the presence of algal pigments. The results obtained show the presence of phytoplankton and algal activity, matching the field observation.

Phenotypic and genotypic characterization of Prototheca zopfii in a dog with enteric signs

This is a case report of enteric protothecosis caused by Prototheca zopfii in an eight-year-old male mixed breed dog with a history of chronic bloody diarrhea, loss of appetite and weight loss. Algae were isolated from rectal scrapings in defibrinated sheep blood agar and dextrose Sabouraud agar. Cytological evaluation showed the presence of globular and cylindrical organisms with a defined capsule and variable number of endospores, characteristic of the genus Prototheca, in the rectum of the animal. Scanning electron microscopy of P. zopfii strains at different development stages confirmed the diagnosis of algal infection. Molecular identification using a conserved 18S rDNA gene sequence determined that the strain belonged to genotype 2. This report describes success on treatment of canine protothecosis, diagnosed based on clinical, cytological, microbiological, scanning electron microscopy and genotypical findings. (c) 2009 Elsevier Ltd. All rights reserved.

Foraging by the omnivorous crab Pachygrapsus transversus affects the structure of assemblages on sub-tropical rocky shores

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Independent and interactive effects of a top and an intermediate fish species on the food web structure of a tropical stream

Two fish species, one top predator (Imparfinis mirini) and one intermediate detritivorous species (Hisonotus depressicauda), were experimentally manipulated to evaluate their relative importance in structuring the periphytic community, as well as their effects on the other trophic levels. An enclosure experiment was conducted in the Potreirinho creek, a second order tributary of Paranapanema River, SE Brazil. Five treatments were used: enclosure of the predator species. enclosure of the detritivorous species, enclosure of both together, exclusion of all fish species (closed control cage), and cage open to all fish community, (open control). Through direct and indirect effects, I. mirini, when alone gave rise to a trophic cascade that resulted in a positive effect on algal resources. Through direct effects, H. depressicauda. when alone, reduced the amount of organic matter, resulting in a positive indirect effect on algae. In addition, when the two species were enclosed together, only the effects determined by the detritivorous species were present. The results indicate the important role of the intermediate detritivorous species in the maintenance of the composition and trophic structure of the analyzed community by reducing the effects caused by the top predator.

Population features of the spider crab Acanthonyx scutiformis (Dana 1851) (Crustacea, Majoidea, Epialtidae) associated with rocky-shore algae from southeastern Brazil.

Acanthonyx scutiformis, an endemic species in the Brazilian coast, is commonly found in intertidal rocky-shore algal communities. This study analyzes the population biology of A. scutiformis from Ubatuba region. A total of 371 specimens were collected over one year. Size range was 4.2[long dash]12.7 mm CW (carapace width) for females and 3.7[long dash]15.8 mm CW for males. Females predominated in intermediate size classes, whereas males prevailed in the largest ones. The estimated size when 50% crabs were mature was 10.7 mm CW for males and 8.9 mm CW for females. Sex ratio varied among the demographic groups. The processes that influence A. scutiformis population structure can be related to the different times males and females reach sexual maturity and probably to the distinct predation pressures on each sex during the adult phase.

Evaluation of the beta-glucanolytic enzyme complex of Trichoderma harzianum Rifai for the production of gluco-oligosaccharide fragments by enzymatic hydrolysis of 1,3;1,6-beta-D-glucans

Botryosphaeran, a new exopolysaccharide from the endophytic fungus Botryosphaeria rhodina MAMB-05, and algal laminarin were hydrolyzed by partially-fractionated enzymes of the beta-glucanolytic complex from Trichoderma harzianum Rifai. beta-Glucanase fractions (F-I and F-II) separated by gel permeation chromatography presented different modes of attack on botryosphaeran and laminarin. Botryosphaeran was hydrolyzed to the extent of 66% (F-I) and 98% (F-II) within 30 min, and its main hydrolysis products were gluco-oligosaccharides of DP >= 4, with lesser amounts of glucose, di- and tri-saccharides. The action of enzyme fractions I and II on laminarin resulted in 15% conversion to glucose, while the percentage of saccharification was radically different (70% for F-I and 25% for F-II). The different product arrays within the polysaccharide hydrolysates can be explained by the difference in the enzymes' specificities within each enzyme fraction, and the molecular structures of the polysaccharides and their complexity.

Distribution of Rhodophyta in streams from São Paulo State, southeastern Brazil

Distribution of Rhodophyta was investigated in 172 stream segments, which were sampled from May to October in 1992-1993 and 1996-1997 in six natural regions (parts of biomes or geological areas) of São Paulo State, southeastern Brazil. Red algae occurred in 60.5 % of stream segments sampled, a high frequency in comparison with other major surveys in the world (18-65 %). 17 species of freshwater red algae were found, of which the most widespread was Batrachospermum delicatulum occurring in 17 sites of five regions. The proportion of morphological types was as follows: gelatinous filaments (62.5 %), free filaments (19 %), tufts (12.5 %) and crusts (6 %); all but free filaments can be considered as having mechanisms to tolerate stress provoked by current velocity. No significant difference was found between the frequency distributions of variables measured for all streams and for those with red algae. Rhodophyta occurred under the following conditions (means): temperature (19.0 degrees C), current velocity (48 cm s(-1)), specific conductance (74 mu S cm(-1)), turbidity (8 NTU), oxygen (67.3 %) and pH (6.9 +/- 0.7). on the basis of species composition among the regions, the following patterns were evident: 1) the number of red algal species per region ranged from 1 to 10; 2) the highest proportion of sites with red algae (65-73 %) was found in hard water regions and in Atlantic rainforest, whereas the lowest (50 %) was found in tropical rainforest; 3) more than half of the species were exclusive from a single region, whereas the higher proportion of exclusive species was in the subtropical rainforest (50 %). No combination of stream variables was clearly associated with the occurrence of red algae for the regions as a whole. Species composition for streams and rivers of São Paulo State revealed higher similarities with other tropical regions and had few species in common with freshwater red algal floras of other continents.

Evaluation of seasonal dynamics and bioindication potential of macroalgal communities in a polluted tropical stream

Macroalgal communities and environmental variables were analyzed seasonally along a polluted tropical stream in São Paulo State, Brazil, We aimed to improve the knowledge of tropical macroalgal communities, to study the longitudinal and seasonal dynamics of these communities in influenced environments, to evaluate the relationship of algal frequency and abundance with selected environmental variables, and to look for potential macroalgal species indicators. The seasonal abundance pattern was similar to natural or low influenced systems and was mainly determined by rainfall regime. However, community composition was closely related to some chemical water pollution indicators, such as phosphorus and nitrogen compounds. Some species are suggested as potential indicators of organic pollution (e.g. Oscillatoria ornata, Stigeoclonium helveticum and Schizomeris leibleinii), but more detailed studies have to be developed to determine the tolerance limits of these species. on the basis of our results and literature data, the use of occurrence of Oscillatoriales in relation to other orders of Cyanoprokaryota is suggested to be a good indicator of organic pollution in tropical lotic ecosystems.

Sirocladium robustum, uma nova espécie de Zygnemataceae (Chlorophyta)

Sirocladium foi descrito por Randhawa (espécie tipo Sirocladium kumaoense) a partir de amostras de uma alga que crescia sobre o solo úmido às margens de uma queda d'água na Índia. O gênero é considerado terrestre e é caracterizado pela presença de apenas dois cloroplastos de forma laminar, bem como pela ocorrência de conjugação sem a formação de tubos. Atualmente, Sirocladium conta com mais três espécies, S. maharashtrense Randhawa, S. vandalurense Randhawa encontradas em solos úmidos da Índia, e S. cubense Rieth que é conhecida de solos úmidos de Cuba. O presente estudo descreve S. robustum, uma nova espécie deste gênero pouco conhecido de Zygnemataceae, cujos espécimes foram coletados crescendo sobre o solo úmido de uma poça permanente na região noroeste do Estado de São Paulo, no Brasil. As maiores dimensões do comprimento e diâmetro das células, a forma e dimensão dos zigósporos são as características mais distintivas de S. robustum das outras quatro espécies deste gênero.