Transcriptome profiling of Paracoccidioides brasiliensis yeast-phase cells recovered from infected mice brings new insights into fungal response upon host interaction

Paracoccidioides brasiliensis is a fungal human pathogen with a wide distribution in Latin America. It causes paracoccidioidomycosis, the most widespread systemic mycosis in Latin America. Although gene expression in P. brasiliensis had been studied, little is known about the genome sequences expressed by this species during the infection process. To better understand the infection process, 4934 expressed sequence tags (ESTs) derived from a non-normalized cDNA library from P. brasiliensis (isolate Pb01) yeast-phase cells recovered from the livers of infected mice were annotated and clustered to a UniGene (clusters containing sequences that represent a unique gene) set with 1602 members. A large-scale comparative analysis was performed between the UniGene sequences of P. brasiliensis yeast-phase cells recovered from infected mice and a database constructed with sequences of the yeast-phase and mycelium transcriptome (isolate Pb01) (https://dna.biomol.unb.br/Pb/), as well as with all public ESTs available at GenBank, including sequences of the P. brasiliensis yeast-phase transcriptome (isolate Pb18) (http:// www.ncbi.nlm.nih.gov/). The focus was on the overexpressed and novel genes. From the total, 3184 ESTs (64.53%) were also present in the previously described transcriptome of yeast-form and mycelium cells obtained from in vitro cultures (https://dna.biomol.unb.br/Pb/) and of those, 1172 ESTs (23.75% of the described sequences) represented transcripts overexpressed during the infection process. Comparative analysis identified 1750 ESTs (35.47% of the total), comprising 649 UniGene sequences representing novel transcripts of P. brasiliensis, not previously described for this isolate or for other isolates in public databases. KEGG pathway mapping showed that the novel and overexpressed transcripts represented standard metabolic pathways, including glycolysis, amino acid biosynthesis, lipid and sterol metabolism. The unique and divergent representation of transcripts in the cDNA library of yeast cells recovered from infected mice suggests differential gene expression in response to the host milieu.

Differential gene expression by Paracoccidioides brasiliensis in host interaction conditions: Representational difference analysis identifies candidate genes associated with fungal pathogenesis

Paracoccidioides brasiliensis causes infection by the host inhalation of airborne propagules of the mycelia phase of the fungus. These particles reach the lungs, and disseminate to virtually all organs. Here we describe the identification of differentially expressed genes in studies of host-fungus interaction. We analyzed two cDNA populations of P. brasiliensis, one obtained from infected animals and the other an admixture of fungus and human blood thus mimicking the hematologic events of the fungal dissemination. Our analysis identified transcripts differentially expressed. Genes related to iron acquisition, melanin synthesis and cell defense were specially upregulated in the mouse model of infection. The upregulated transcripts of yeast cells during incubation with human blood were those predominantly related to cell wall remodeling/synthesis. The expression pattern of genes was independently confirmed in host conditions, revealing their potential role in the infection process. This work can facilitate functional studies of novel regulated genes that may be important for the survival and growth strategies of P. brasiliensis in humans. (c) 2006 Elsevier Masson SAS. All rights reserved.

Virus-host interaction in feline immunodeficiency virus (FIV) infection

Feline immunodeficiency virus (FIV) infection has been the focus of several studies because this virus exhibits genetic and pathogenic characteristics that are similar to those of the human immunodeficiency virus (HIV). FIV causes acquired immunodeficiency syndrome (AIDS) in cats, nevertheless, a large fraction of infected cats remain asymptomatic throughout life despite of persistent chronic infection. This slow disease progression may be due to the presence of factors that are involved in the natural resistance to infection and the immune response that is mounted by the animals, as well as due to the adaptation of the virus to the host. Therefore, the study of virus-host interaction is essential to the understanding of the different patterns of disease course and the virus persistence in the host, and to help with the development of effective vaccines and perhaps the cure of FIV and HIV infections. © 2013 Elsevier Ltd. All rights reserved.

Parasitoid-host interaction: sensory structures involved in the parasitism behavior of Bracon vulgaris (Hymenoptera: Braconidae)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização fenotípica e funcional de mutantes da bactéria fitopatogênica Xanthomonas citri subsp. citri

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Herança da resistência a oídio em ervilha e aspectos relacionados à patogênese

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Importance of adhesins in virulence of Paracoccidioides spp.

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

Phytophthora parasitica transcriptome, a new concept in the understanding of the citrus gummosis

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

Diversidade de fungos associados a Parlatoria ziziphus (Lucas)(Hemiptera: Diaspididae) em Citros

As espécies de entomopatógenos que causam impacto em populações de hospedeiros são muitas. Entretanto, informações básicas sobre sua biologia, identificação e relação entre o sistema patógeno-hospedeiro são escassas. Este estudo teve por objetivo identificar os fungos associados a Parlatoria ziziphus (Lucas)em pomares citrícolas do município de Taiúva, SP. Foram realizadas coletas mensais, em dois pomares de laranja (Citrus sinensis Osbeck), variedade Pera, de janeiro de 1995 a fevereiro de 1996. Amostraram-se 15 árvores em cada pomar, retirando-se 16 folhas por árvore. Estas foram levadas ao laboratório, para determinação dos fungos associados à cochonilha. Para a identificação dos fungos, consideraram-se aspectos da estrutura reprodutiva e do esporo. Foram identificadas cinco espécies, citadas como patógenos de diaspidídeos por vários autores: Fusarium coccophilum (Desm.) Wr. & Rg., Nectria flammea (Tul.) Dingley (fase sexual de F. coccophilum), Tetracrium coccicolum Hohnell, Podonectria coccicola (Ellis & Everhart) Petch (fase sexual de T. coccicolum) e Myriangium duriaei Mont. & Berk. Fusarium coccophilum foi a espécie mais freqüente e a mais prevalente, na maioria das coletas realizadas, em ambas as áreas amostradas.

New genes of Xanthomonas citri subsp citri involved in pathogenesis and adaptation revealed by a transposon-based mutant library

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

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.

Thermodynamic aspects of ion intercalation in KhFek[Fe(CN)(6)](l)center dot mH(2)O compounds: Application to the Everit's salt/Prussian Blue transition

The K+ reversible processes for ion exchange in KhFek[Fe(CN)(6)](l)center dot mH(2)O host compounds (Prussian Blue) were thermodynamically analyzed. A thermodynamic approach was established and developed based on the consideration of a lattice-gas model where the electronic contribution to the chemical potential is neglected and the ion-host interaction is not considered. The occupation fraction of the intercalation process was calculated from the kinetic parameters obtained through ac-electrogravimetry in a previous paper. In this way, the mass potential transfer function introduces a new way to evaluate the thermodynamic aspect of intercalation. Finally, based on the thermodynamic approach, the energy used to put each K+ ion into the host material was calculated. The values were shown to be in good agreement with the values obtained through transient techniques, for example, cyclic voltammetry. As a result, this agreement between theory and experimental data validates the thermodynamic approach considered here, and for the first time, the thermodynamic aspects of insertion were considered for mixed valence materials.

Alternatives for the Treatment of Schistosomiasis: Physico-Chemical Characterization of an Inclusion Complex Between Praziquantel and Hydroxypropyl-beta-Cyclodextrin

"Alternatives for the Treatment of Schistosomiasis: Physico-Chemical Characterization of an Inclusion Complex Between Praziquantel and Hydroxypropyl-beta-Cyclodextrin". Praziquantel (PZQ) is the drug of choice commonly used for the treatment of shistosomiasis. However, it has low aqueous solubility, which could limit its bioavailability in the body. To circumvent these features, an inclusion complex with hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was prepared. Thus, the objective of this work was to prepare and characterize the PZQ/HP-beta-CD inclusion complex. Morphological, spectroscopic, and calorimetric analysis showed the first signs of the guest/host interaction. The complexation kinetic analysis was used to determine the kinetic constant and, besides that, it was possible to establish the time consumed to reach equilibrium. Using the solubility isotherm, it was observed that the interaction with HP-beta-CD increased 2.4 fold the aqueous solubility of plain PZQ. In vitro cytotoxicity tests, using fibroblast cells, evidenced no toxicity for these cells at the concentrations tested. These results demonstrated that there is a potential use of PZQ in formulations with HP-beta-CD.

Alternativas para o tratamento da esquistossomose: Caracterizacao fisico-quimica do complexo de inclusao entre praziquantel e hidroxipropil-β-ciclodextrina

Praziquantel (PZQ) is the drug of choice commonly used for the treatment of shistosomiasis. However, it has low aqueous solubility, which could limit its bioavailability in the body. To circumvent these features, an inclusion complex with hydroxypropyl-beta- cyclodextrin (HP-β-CD) was prepared. Thus, the objective of this work was to prepare and characterize the PZQ/HP-β-CD inclusion complex. Morphological, spectroscopic, and calorimetric analysis showed the first signs of the guest/host interaction. The complexation kinetic analysis was used to determine the kinetic constant and, besides that, it was possible to establish the time consumed to reach equilibrium. Using the solubility isotherm, it was observed that the interaction with HP-β-CD increased 2.4 fold the aqueous solubility of plain PZQ. In vitro cytotoxicity tests, using fibroblast cells, evidenced no toxicity for these cells at the concentrations tested. These results demonstrated that there is a potential use of PZQ in formulations with HP-β-CD.

Interação patógeno-hospedeiro no patossistema capim limão-ferrugem das folhas e avaliação de ingredientes ativos naturais no controle da doença

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)