Paracoccidioides brasiliensis: phylogenetic and ecological aspects

The knowledge on the biological aspects of Paracoccidioides brasiliensis has evolved greatly since the first description of the disease in 1908. From the pioneers, who were able to clearly demonstrate the fungal nature of the agent, to the recent genomic era, important advances have been achieved. P. brasiliensis is a true fungus, belonging to the Ascomycetous Division, although its sexual phase has not been demonstrated morphologically. A better understanding of the fundamental aspects of the agent, especially its phylogeny and evolutionary history, will provide us with valuable insights allowing a better comprehension of the disease and our capacity to deal with the problem. Concerning the fungus's ecology, although some progress had been observed, the ecological niche of the pathogen has not been determined yet. The aim of the present review is to focus on the biological aspects of P. brasiliensis from an evolutionary point of view, addressing the fungus's phylogenetic aspects, in those special points that might be relevant for the pathogen/host interactions, the biological forces that have been acting on its origin and maintenance of virulence, as well as in determining the fungus's ecology and epidemiology.

Phylogenetic analysis of PRP8 intein in Paracoccidioides brasiliensis species

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

Role of TLR2 and TLR4 in Human Neutrophil Functions Against Paracoccidioides brasiliensis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A synthetic peptide selectively kills only virulent Paracoccidioides brasiliensis yeasts

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

Efficacy of Duddingtonia flagrans and Arthrobotrys robusta in controlling sheep parasitic gastroenteritis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Survival of Atta sexdens workers on different food sources

Leaf-cutting ants belonging to the tribe Attini are major herbivores and important agriculture pests in the neotropics, these ants being thought to feed on the sap which exudes from the plant material which they cut and also on the mycelium of a symbiotic fungus that grows on plant material inside their nests in what is called 'the fungus garden'. However, we have found that the survival of Atta sexdens worker ants on leaves, on mycelium. of the ants' symbiotic fungus, Leucoagaricus gongylophorus, or on plant polysaccharides was the same as that of starved A. sexdens, while, conversely, significantly longer survival was achieved by ants fed on the fungus garden material or on some of the products (especially glucose) of the hydrolysis of plant polysaccharides. We found that the fungus garden contained glucose at a higher concentration than that found in leaves or fungal mycelium, and that this glucose was consumed by the ant to the extent that it was probably responsible for up to 50% of the nutritional needs of the workers. The fungus garden contained polysaccharide degrading enzymes (pectinase, amylase, xylanase and cellulase) in proportions similar to that observed in laboratory cultures of L. gongylophorus. It thus appears that A. sexdens workers obtain a significant part of their nutrients from plant polysaccharide hydrolysis products produced by the action of extracellular enzymes released by L. gongylophorus. In this paper we discuss the symbiotic nutrition strategy of A. sexdens workers and brood and the role played by plant polysaccharides in the nutrition of attine ants. (C) 2003 Elsevier B.V. Ltd. All rights reserved.

First evidence of an intimate symbiotic association between fungi and larvae in basal attine ants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Secretory Profile of Metapleural Gland Cells of the Leaf-Cutting Ant Acromyrmex coronatus (Formicidae: Attini)

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

Ultrastructural profile of metapleural gland cells of the ant Atta laevigata (F. Smith, 1858) (Formicidae: Attini)

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

Production of extracellular acid proteases by Aspergillus clavatus

The production of extracellular acid proteases from Aspergillus clavatus was evaluated in a culture filtrate medium, with different carbon and nitrogen sources. The fungus was cultivated at three different temperatures during 10 days. The proteolytic activity was determined on haemoglobin pH 5.0 at 37 degreesC. The highest acid proteolytic activity (80 U/ml) was observed in culture medium containing glucose and gelatin at 1% (w/v) at 30 degreesC at the third day of incubation. Cultures developed in Vogel medium with glucose at 2% (w/v) showed at about 45% of proteolytic activity when compared to the cultures with 1% of the same sugar. The optimum pH of enzymatic activity was 2.0 and the enzyme was stable at pH values ranging from 2.0 to 4.0. The optimum temperature was 40 degreesC and the half-lives at 40, 45 and 50 degreesC were 30, 10 and 5 min, respectively.

Xylanase production by Aspergillus versicolor

The xylanolytic system of Aspergillus versicolor is controlled by induction and carbon catabolite repression. Carboxymethylcellulose and wheat bran were the best inducers of xylanolytic activity. When the fungus was grown for 5 days on VOGEL's liquid medium with wheat bran, the optimal pH and temperature for xylanase production were 6.5 and 30 degrees C, respectively. Optimal conditions for the xylanolytic activity assay were at pH 6.0 and 55 degrees C. The half-life at 60 degrees C of the crude enzyme was 6.5 and 21 minutes, in the absence or presence of substrate, respectively.Xylan is the main hemicellulosic component of plant biomass being present in appreciable quantities in agricultural and several agroindustrial wastes. From the products of xylan enzymatic hydrolysis it is possible to obtain cell protein, fuels and other chemicals. Xylanases combined with cellulase could have applications in food processing. Cellulase-free xylanases can be also utilized for preparation of cellulose pulps and liberation of textile fibres (WOODWARD 1984; BIELY 1985, WONG et al. 1988). In view of the potential applications of xylanases, a study of these enzymes from various sources and their multiplicity is desirable.Among xylanolytic microorganisms, filamentous fungi have been more extensively studied and the genus Aspergillus has been shown to be an efficient producer of xylanases. Preliminary observations from our laboratory have demonstrated that a strain of Aspergillus versicolor, isolated from Brazilian soil, produced high xylanase and low cellulase levels, which is an interesting characteristic for some industrial applications. In this report we describe the production and some properties of xylanase obtained from this fungus.

Occurrence of Winged Forms of Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae) in Laboratory Colonies

Foi observada, pela primeira vez no Brasil, a produção de centenas de formas aladas em formigueiros de Atta sexdens rubropilosa Forel, mantidos em laboratório. Larvas de último instar de machos foram encontradas em 5 de agosto de 2000 em um formigueiro com quase seis anos de fundação, contendo aproximadamente 110 L de esponja de fungo distribuída em 21 panelas. Entre 30 e 40 dias mais tarde apareceram larvas de fêmeas aladas. Os adultos sexuados apresentaram tamanhos compatíveis com os encontrados em formigueiros de campo. Foram observadas duas aparentes tentativas frustradas de revoada na última semana de outubro, após o que começaram a aparecer machos e fêmeas mortos no lixo do formigueiro.

Production and characteristics comparison of crude beta-glucosidases produced by microorganisms Thermoascus aurantiacus e Aureobasidium pullulans in agricultural wastes

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

Leaf-cutting ant faecal fluid and mandibular gland secretion: effects on microfungi spore germination

The mandibular gland secretion (MGS) and the faecal fluid (FF) of the leaf-cutting ant Atta sexdens rubropilosa Forel affected the spore germination of selected microfungi isolated from nests of this insect. MGS was more effective than the FF, completely inhibiting the spore germination of four out of six microfungi species.

Production of xylanolytic enzymes by Penicillium janczewskii

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)