Cryptic speciation and recombination in the fungus Paracoccidioides brasiliensis as revealed by gene genealogies

Paracoccidioides brasiliensis is the etiologic agent of paracoccidioidomycosis, a disease confined to Latin America and of marked importance in the endemic areas due to its frequency and severity. This species is considered to be clonal according to mycological criteria and has been shown to vary in virulence. To characterize natural genetic variation and reproductive mode in this fungus, we analyzed P. brasiliensis phylogenetically in search of cryptic species and possible recombination using concordance and nondiscordance of gene genealogies with respect to phylogenies of eight regions in five nuclear loci. Our data indicate that this fungus consists of at least three distinct, previously unrecognized species: S1 (species 1 with 38 isolates), PS2 (phylogenetic species 2 with six isolates), and PS3 (phylogenetic species 3 with 21 isolates). Genealogies of four of the regions studied strongly supported the PS2 clade, composed of five Brazilian and one Venezuelan isolate. The second clade, PS3, composed solely of 21 Colombian isolates, was strongly supported by the alpha-tubulin genealogy. The remaining 38 individuals formed S1. Two of the three lineages of P. brasiliensis, S1 and PS2, are sympatric across their range, suggesting barriers to gene flow other than geographic isolation. Our study provides the first evidence for possible sexual reproduction in P. brasiliensis S1, but does not rule it out in the other two species.

Efficacy of the nematode-trapping fungus Duddingtonia flagrans against infections by Haemonchus and Trichostrongylus species in lambs at pasture

The efficacy of the nematode-trapping fungus Duddingtonia flagrans against infections by trichostrongyle nematodes in sheep was assessed throughout 6 months. Twenty Ile de France lambs were divided into two groups (control and treated groups), which were kept in separate pastures. Animals of the treated group were fed with D. flagrans twice a week (Tuesdays and Fridays). Pellets were prepared with the fungus mycelia in liquid culture medium and contained approximately 20% fungus. They were mixed with the animals' diet at a concentration of 1 g pellet per 10 kg live weight. Faecal egg counts (FEC), packed cell volume (PCV), total serum protein and the animals' body weight were determined fortnightly from 7 October 2005 to 24 March 2006. Comparison of such parameters between groups showed no significant differences (P > 0.05), except on 10 February 2006, when the control group presented a higher mean FEC than the treated group (P < 0.05). Feeding sheep with pellets containing D. flagrans had no benefit to the prophylaxis of nematode infections under the experimental conditions used in the present study.

Substrate distribution in fungus chambers in nests of Atta bisphaerica Forel, 1908 (Hym., Formicidae)

Substrate distribution was studied in three adult colonies of the leaf-cutting ant Atta bisphaerica Forel, 1908 using dye. Some supply holes were mapped using baits made from small plastic straws impregnated with citric pulp. Two holes, equidistant from one another, were then selected in each nest. The colonies were excavated completely 24 h after bait placement. During excavation, fungus chambers were checked for dye. We observed that the dyed baits were distributed in all sectors and at all depths regardless of where the baits had been placed. This supported the hypothesis that toxic baits placed in a single supply hole are uniformly distributed throughout the colony.

Influence of physical and chemical factors during foraging and culture of the symbiont fungus in Atta sexdens rubropilosa (Hymenoptera : Formicidae)

The aim of this paper is to investigate the influence of physical and chemical factors on transport and use of substrate for Atta sexdens rubropilosa workers. Three types of rectangular fragments were used to study the physical influence factors: filter paper with paraffin, filter paper without paraffin and polyester film. To study the chemical factors, some fragments were impregnated with organic extract of orange albedo, others were soaked with soybean oil and for the remaining ones nothing was applied. The following parameters were evaluated: (i) attractiveness of substrate for transport and number of loading workers per treatment; (ii) foraged material incorporation; (iii) rejection by numbers of fragments deposited in the garbage or beside the fungus garden. All the polyester film fragments carried out to the fungus garden were subsequently rejected. We verified that chemical factors of the substrate were more quickly detected by the workers, whereas physical factors were used as a criterion in the decision-making to reject or accept the substrate collected.

Evolution of Substrate Preparation Behaviors for Cultivation of Symbiotic Fungus in Attine Ants (Hymenoptera: Formicidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Microfungal 'Weeds' in the Leafcutter Ant Symbiosis

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Production, partial characterization, and immobilization in alginate beads of an alkaline protease from a new thermophilic fungus Myceliophthora sp.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ecology of microfungal communities in gardens of fungus-growing ants (Hymenoptera: Formicidae): a year-long survey of three species of attine ants in Central Texas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)National Science Foundation (NSF)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Cryptic sexual populations account for genetic diversity and ecological success in a widely distributed, asexual fungus-growing ant

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

A new workerless inquiline in the Lower Attini (Hymenoptera: Formicidae), with a discussion of social parasitism in fungus-growing ants

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

Activities of Extracts and Compounds from Spiranthera odoratissima St. Hil. (Rutaceae) in Leaf-cutting Ants and their Symbiotic Fungus

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Use of sugarcane bagasse and grass hydrolysates as carbon sources for xylanase production by Bacillus circulans D1 in submerged fermentation

The use of sugarcane bagasse and grass as low cost raw material for xylanase production by Bacillus circulans D1 in submerged fermentation was investigated. The microorganism was cultivated in a mineral medium containing hydrolysate of bagasse or grass as carbon source. High production of enzyme was obtained during growth in media with bagasse hydrolysates (8.4 U/mL) and in media with grass hydrolysates (7.5 U/mL). Xylanase production in media with hydrolysates was very close to that obtained in xylan containing media (7.0 U/ mL) and this fact confirm the feasibility of using this agro-industrial byproducts by B. circulans D1 as an alternative to save costs on the enzyme production process. (c) 2005 Elsevier Ltd. All rights reserved.

Tissue alterations in the Guinea pig lateral prostate following antiandrogen flutamide therapy

The flutamide antiandrogenic effects oil the Guinea pig male prostate morphology in puberal, post-puberal and adult ages were evaluated in the present study. Daily-treated group animals received flutamide Subcutaneous injection at a dose of 10 mg/Kg body weight for 10 days. The control group animals received a pharmacological vehicle under the same conditions. The lateral prostate was removed, fixed and processed for light and transmission electron microscopy. The results revealed all increase of the acinus diameter in the treated puberal animals and straitness in the stromal compartment around the acini. The epithelial cells exhibited cubic phenotype. In the post-puberal and adult animals, a decrease of the acinus diameter was observed, as well as an increase of the smooth muscle layer and presence of the folds at epithelium. The ultrastructural evaluation of the secretory cells in the treated group demonstrated endomembrane enlargement, mainly in the rough endoplasmic reticulum and Golgi apparatus. In addition, a decrease of the microvilli and alterations in the distribution patterns and density of the stromal fibrillar components were observed. In Conclusion, the flutamide treatment exerts tissue effects oil the lateral prostate, promoting stroma/epithelium alterations.

Production and characterization of glucoamylase from fungus Aspergillus awamori expressed in yeast Saccharomyces cerevisiae using different carbon sources

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

Short-Term Antiandrogen Flutamide Treatment Causes Structural Alterations in Somatic Cells Associated with Premature Detachment of Spermatids in the Testis of Pubertal and Adult Guinea Pigs

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