Inteins in pathogenic fungi: a phylogenetic tool and perspectives for therapeutic applications

Inteins or internal proteins are coding sequences that are transcribed and translated with flanking sequences (exteins). After translation, the inteins are excised by an autocatalytic process and the host protein assumes its normal conformation and develops its expected function. These parasitic genetic elements have been found in important, conserved proteins in all three domains of life. Most of the eukaryotic inteins are present in the fungi kingdom and the PRP8 intein is one of the most widespread inteins, occurring in important pathogens such as Cryptococcus neoformans (varieties grubii and neoformans), Cryptococcus gattii, Histoplasma capsulatum and Paracoccidioides brasiliensis. The knowledge of conserved and non-conserved domains in inteins have opened up new opportunities for the study of population variability in pathogenic fungi, including their phylogenetic relationships and recognition or diagnoses of species. Furthermore, inteins in pathogenic fungi should also be considered a promising therapeutic drug target, since once the autocatalytic splicing is inhibited, the host protein, which is typically vital, will not be able to perform its normal function and the fungal cell will not survive or reproduce.

Advantages of using nested collision induced dissociation/post-source decay with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry: sequencing of novel peptides from wasp venom

We have examined the applicability of the 'nested' collision induced dissociation/post-source decay (CID/PSD) method to the sequencing of novel peptides from solitary wasps which have neurotoxic venom for paralyzing other insects. The CID/PSD spectrum of a ladder peptide derived from an exopeptidase digest was compared with that of the intact peptide. The mass peaks observed only in the CID/PSD spectrum of a ladder peptide were extracted as C-terminal fragment ions. Assignment of C-terminal fragment ions enabled calculation of N-terminal fragment masses, leading to differentiation between N-terminal fragment ions and internal fragment ions. This methodology allowed rapid and sensitive identification by removing ambiguity in the assignment of the fragment ions, and proved useful for sequencing unknown peptides, in particular those available as natural products with a limited supply. Copyright (C) 2000 John Wiley & Sons, Ltd.

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

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Yeasts and filamentous fungi carried by the gynes of leaf-cutting ants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

beta-Xylosidases from filamentous fungi: an overview

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Filamentous fungi found in Atta sexdens rubropilosa colonies after treatment with different toxic bait formulations

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Selective isolation of dematiaceous fungi from the workers of Atta laevigata (Formicidae: Attini)

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

Intracellular papillae of Actinocephalus (Eriocaulaceae-Poales) roots and their interaction with fungi: A light and transmission electron microscopy study

The genus Actinocephalus comprises 25 species and is restricted to Brazil, occurring mainly in the Espinhaco Mountains of Minas Gerais and Bahia States. Previous anatomical studies have reported the occurrence of intracellular papillae in the Actinocephalus roots, without dealing with their ultrastructure and function. The purpose of this paper is to investigate the structure, the composition and the probable function of the intracellular papillae of Actinocephalus roots, based on light microscopy, transmission electron microscopy and histochemical tests. The intracellular papillae occurred in all root tissues, from the rhizodermis to the vascular cylinder; they presented different forms and sizes and, ultrastructurally, they corresponded to material deposited between the cell wall and the plasma membrane. The histochemical tests carried out were positive for cellulose, pectin and callose. The intracellular papillae are responses of the plant cells to the interaction with fungi. They work as a physical barrier restricting fungal penetration, and they may also favor the supply of water and nutrients to the plant, since they increase root absorption surface. This might explain why the species of Actinocephalus are among the tallest Eriocaulaceae despite their reduced radicular system and the nutritional deficiency of the soil in which they grow. (C) 2006 Elsevier Ltd. All rights reserved.

Screening of culture condition for xylanase production by filamentous fungi

The objective of this research was to investigate xylanase production by filamentous fungi (Trichoderma viride) to determine the best cultivation conditions in the process, aiming toward optimization of enzyme production. The best temperature, as well as the best carbon source, for biomass production was determined through an automated turbidimetric method (Bioscreen-C). The enzyme activity of this fungus was separately evaluated in two solid substrates (wheat and soybean bran) and in Vogel medium, pure and by adding other carbon sources. Temperature effects, cultivation time, and spore concentrations were also tested. The best temperature and carbon source for enzyme and biomass production was 25 C and sorbitol, respectively. Maximum xylanase activity was achieved when the fungus was cultivated in wheat bran along with sorbitol (1%, w/v), using a spore concentration of 2 x 10(6) spores. mL(-1), pH 5.0, for 144 h cultivation. The study demonstrated not only the importance of the nature of the substrate in obtaining a system resistant to catabolic repression, but also the importance of the culture conditions for biosynthesis of this enzyme. T. viride showed a high potential for xylanase production under the conditions presented in these assays.

Selection of thermophilic and thermotolerant fungi for the production of cellulases and xylanases under solid-state fermentation

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

Protease production by different thermophilic fungi

A comparative study was carried out to evaluate protease production in solid-state fermentation (SSF) and submerged fermentation (SmF) by nine different thermophilic fungi - Thermoascus aurantiacus Miehe, Thermomyces lanuginosus, T. lanuginosus TO.03, Aspergillus flavus 1.2, Aspergillus sp. 13.33, Aspergillus sp. 13.34, Aspergillus sp. 13.35, Rhizomucor pusillus 13.36 and Rhizomucor sp. 13.37 - using substrates containing proteins to induce enzyme secretion. Soybean extract (soybean milk), soybean flour, milk powder, rice, and wheat bran were tested. The most satisfactory results were obtained when using wheat bran in SSF. The fungi that stood out in SSF were T. lanuginosus, T. lanuginosus TO.03, Aspergillus sp. 13.34, Aspergillus sp. 13.35, and Rhizomucor sp. 13.37, and those in SmF were T. aurantiacus, T. lanuginosus TO.03, and 13.37. In both fermentation systems, A. flavus 1.2 and R. pusillus 13.36 presented the lowest levels of proteolytic activity.

Muon transverse polarization in the K-l2 gamma decay in the standard model

The muon transverse polarization in the K+-->mu(+)nugamma process induced by the electromagnetic final state interaction is calculated in the framework of the standard model. It is shown that one loop contributions lead to a nonvanishing muon transverse polarization. The value of the muon transverse polarization averaged over the kinematical region of E(gamma)greater than or equal to20 MeV is equal to 5.63x10(-4).

Search for right-handed W bosons in top quark decay

We present a measurement of the fraction f(+) of right-handed W bosons produced in top quark decays, based on a candidate sample of t (t) over bar events in the lepton+jets decay mode. These data correspond to an integrated luminosity of 230 pb(-1), collected by the D0 detector at the Fermilab Tevatron p (p) over bar Collider at root s=1.96 TeV. We use a constrained fit to reconstruct the kinematics of the t (t) over bar and decay products, which allows for the measurement of the leptonic decay angle theta(*) for each event. By comparing the cos theta(*) distribution from the data with those for the expected background and signal for various values of f(+), we find f(+)=0.00 +/- 0.13(stat)+/- 0.07(syst). This measurement is consistent with the standard model prediction of f(+)=3.6 x 10(-4).