Célia Maria Almeida Soares - Academia.edu (original) (raw)

Papers by Célia Maria Almeida Soares

BMC genomics, Jan 14, 2006

Mycelium-to-yeast transition in the human host is essential for pathogenicity by the fungus Parac... more Mycelium-to-yeast transition in the human host is essential for pathogenicity by the fungus Paracoccidioides brasiliensis and both cell types are therefore critical to the establishment of paracoccidioidomycosis (PCM), a systemic mycosis endemic to Latin America. The infected population is of about 10 million individuals, 2% of whom will eventually develop the disease. Previously, transcriptome analysis of mycelium and yeast cells resulted in the assembly of 6,022 sequence groups. Gene expression analysis, using both in silico EST subtraction and cDNA microarray, revealed genes that were differential to yeast or mycelium, and we discussed those involved in sugar metabolism. To advance our understanding of molecular mechanisms of dimorphic transition, we performed an extended analysis of gene expression profiles using the methods mentioned above. In this work, continuous data mining revealed 66 new differentially expressed sequences that were MIPS(Munich Information Center for Protei...

Medical Mycology, 2005

A cDNA coding for a new member of the 70-kDa heat shock proteins (HSP70) family from the dimorphi... more A cDNA coding for a new member of the 70-kDa heat shock proteins (HSP70) family from the dimorphic and pathogenic fungus, Paracoccidioides brasiliensis, was cloned and characterized. The cDNA-deduced sequence coded for 655 amino acid residues and showed 95% identity to a previously described P. brasiliensis hsp70 gene. Cytoplasmic and typical nuclear localization signals, which indicate induction upon stress, were identified in the deduced peptide. The complete hsp70 cDNA coding region was cloned into a pGEX 4T-3 plasmid and expressed in Escherichia coli as a glutathione-S-transferase-tagged fusion protein. The recombinant protein reacted with a rabbit polyclonal antibody against HSP70. Western immunoblot experiments demonstrated that sera from paracoccidioidomycosis patients recognized the purified recombinant protein, suggesting an immunological role for this protein in the infectious process. The antigenicity analysis of rHSP70 detected three internal peptides that could act as activators of T-cell proliferation.

Journal of Biological Chemistry, 2005

Frontiers in Microbiology, 2015

Future microbiology, Oct 1, 2018

The shape-based virtual screening was used for the identification of new compounds anti-paracocci... more The shape-based virtual screening was used for the identification of new compounds anti-paracoccidioidomycosis (PCM). The study was performed according to the following steps: collection and curation of a dataset of quinolinyl N-oxide chalcones with anti-PCM activity, development and validation of shape-based models, application of the best model for virtual screening, and experimental validation. Among 31 computational hits, eight compounds showed potent antifungal activity and low cytotoxicity for mammalian cells. The checkerboard assay showed that most promising hit (compound 3) displayed additive effects with the antifungal cotrimoxazole and amphotericin B. Therefore, the shape-based virtual screening allowed us to discover promising compounds in prospective hit-to-lead optimization studies for tackling PCM.

Virus genes, 2018

Human Adenoviruses (HAdVs) are etiological agents of different syndromes such as gastroenteritis,... more Human Adenoviruses (HAdVs) are etiological agents of different syndromes such as gastroenteritis, cystitis, ocular, and respiratory diseases, and infection by these viruses may cause alterations in cellular homeostasis. The objective of the study was the proteomic analysis of A-549 cells infected with HAdV-40 using LC-MS. At 30 h of infection, the quantitative analysis revealed 336 differentially expressed proteins. From them, 206 were induced (up-regulated) and 130 were suppressed (down-regulated). The majority of up-regulated proteins were related to energy, cellular organization, stress response, and apoptosis pathways. It was observed alteration of cell metabolism with increase of the glycolytic pathway, β-oxidation, and respiratory chain. Also, the results suggest cytoskeleton reorganization and apoptosis induction. The data can improve knowledge about the replication of HAdV-40 in cell culture considering the proteins related to distinct metabolic pathways induced by viral inf...

Fems Yeast Research, 2008

Medical Mycology, Jul 1, 2004

Glyceollins are soybean (Glycine max) phytoalexins possessing pterocarpanoid skeletons with cycli... more Glyceollins are soybean (Glycine max) phytoalexins possessing pterocarpanoid skeletons with cyclic ether decoration originating from a C 5 prenyl moiety. Enzymes involved in glyceollin biosynthesis have been thoroughly characterized during the early era of modern plant biochemistry, and many genes encoding enzymes of isoflavonoid biosynthesis have been cloned, but some genes for later biosynthetic steps are still unidentified. In particular, the prenyltransferase responsible for the addition of the dimethylallyl chain to pterocarpan has drawn a large amount of attention from many researchers due to the crucial coupling process of the polyphenol core and isoprenoid moiety. This study narrowed down the candidate genes to three soybean expressed sequence tag sequences homologous to genes encoding homogentisate phytyltransferase of the tocopherol biosynthetic pathway and identified among them a cDNA encoding dimethylallyl diphosphate: (6aS, 11aS)-3,9,6a-trihydroxypterocarpan [(2)-glycinol] 4-dimethylallyltransferase (G4DT) yielding the direct precursor of glyceollin I. The full-length cDNA encoding a protein led by a plastid targeting signal sequence was isolated from young soybean seedlings, and the catalytic function of the gene product was verified using recombinant yeast microsomes. Expression of the G4DT gene was strongly up-regulated in 5 to 24 h after elicitation of phytoalexin biosynthesis in cultured soybean cells similarly to genes associated with isoflavonoid pathway. The prenyl part of glyceollin I was demonstrated to originate from the methylerythritol pathway by a tracer experiment using [1-13 C]Glc and nuclear magnetic resonance measurement, which coincided with the presumed plastid localization of G4DT. The first identification of a pterocarpan-specific prenyltransferase provides new insights into plant secondary metabolism and in particular those reactions involved in the disease resistance mechanism of soybean as the penultimate gene of glyceollin biosynthesis.

PLoS neglected tropical diseases, 2015

Hypoxic microenvironments are generated during fungal infection. It has been described that to su... more Hypoxic microenvironments are generated during fungal infection. It has been described that to survive in the human host, fungi must also tolerate and overcome in vivo microenvironmental stress conditions including low oxygen tension; however nothing is known how Paracoccidioides species respond to hypoxia. The genus Paracoccidioides comprises human thermal dimorphic fungi and are causative agents of paracoccidioidomycosis (PCM), an important mycosis in Latin America. In this work, a detailed hypoxia characterization was performed in Paracoccidioides. Using NanoUPLC-MSE proteomic approach, we obtained a total of 288 proteins differentially regulated in 12 and 24 h of hypoxia, providing a global view of metabolic changes during this stress. In addition, a functional characterization of the homologue to the most important molecule involved in hypoxia responses in other fungi, the SREBP (sterol regulatory element binding protein) was performed. We observed that Paracoccidioides species...

Medical mycology, Jan 7, 2015

Paracoccidioidomycosis (PCM) is the most prevalent mycosis in Latin America and is caused by a gr... more Paracoccidioidomycosis (PCM) is the most prevalent mycosis in Latin America and is caused by a group of fungi within the Paracoccidioides genus. The disease may present clinical and pathological manifestations ranging from asymptomatic pneumonia pulmonary lesions, to disseminated forms involving multiple organs. Sulfonamides were the first drugs used to treat PCM and are still used against this fungal infection. Sulfa drugs are competitive antagonists of ρ-aminobenzoic acid (PABA), a reaction catalyzed by dihydropteroate synthase (DHPS). However, the molecular effects of sulfonamides against the Paracoccidioides genus are unknown. The aim of this work was to investigate the global mechanism of action of sulfamethoxazole on Paracoccidioides lutzii. Yeast cells were grown on minimum medium in the presence or absence of sulfamethoxazole to construct EST libraries. The representational difference analysis (RDA) technique was used to identify up- and down-regulated P. lutzii genes after ...

Microbes and infection / Institut Pasteur, 2015

Paracoccidioidomycosis (PCM) is an endemic disease in Latin America caused by species belonging t... more Paracoccidioidomycosis (PCM) is an endemic disease in Latin America caused by species belonging to the genus Paracoccidioides. During infection, immune cells present a variety of defense mechanisms against pathogens. One of these defensive strategies is the production and release of nitric oxide (NO) and S-nitroso thiols (e.g., S-nitrosoglutathione, GSNO), which produce reactive nitrogen species (RNS). This results in damage to DNA and membranes, inhibition of respiration and inactivation of cellular enzymes. In response to nitrosative stress, human pathogenic fungi possess defense mechanisms to prevent the adverse effects of NO, which helps them survive during initial contact with the host immune system. To understand how Paracoccidioides spp. respond to nitrosative stress, we conducted this study to identify genes and proteins that might contribute to this response. The results of proteomic analysis demonstrated that nitrosative stress induced a reduction in the expression of prot...

Infection and Immunity, 2014

ABSTRACTTuberculosis (TB) remains a major global health problem, and although multiple studies ha... more ABSTRACTTuberculosis (TB) remains a major global health problem, and although multiple studies have addressed the relationship betweenMycobacterium tuberculosisand the host on an immunological level, few studies have addressed the impact of host physiological responses. Proteases produced by bacteria have been associated with important alterations in the host tissues, and a limited number of these enzymes have been characterized in mycobacterial species.M. tuberculosisproduces a protease called Zmp1, which appears to be associated with virulence and has a putative action as an endothelin-converting enzyme. Endothelins are a family of vasoactive peptides, of which 3 distinct isoforms exist, and endothelin 1 (ET-1) is the most abundant and the best-characterized isoform. The aim of this work was to characterize the Zmp1 protease and evaluate its role in pathogenicity. Here, we have shown thatM. tuberculosisproduces and secretes an enzyme with ET-1 cleavage activity. These data demonst...

Journal of clinical microbiology, 2000

We have amplified and sequenced the 5.8S and 28S ribosomal DNA genes and intergenic regions of Pa... more We have amplified and sequenced the 5.8S and 28S ribosomal DNA genes and intergenic regions of Paracoccidioides brasiliensis, strain Pb01. Using primers specifically designed for both ribosomal DNA regions, we were able to discriminate between P. brasiliensis and other human pathogenic fungi by PCR. The use of this molecular marker could be important for paracoccidiodomycosis diagnosis and ecological and molecular epidemiological studies of P. brasiliensis in Latin America.

Genetics and molecular research : GMR, Jan 31, 2004

The availability of the complete genome of the Gram-negative beta-proteobacterium Chromobacterium... more The availability of the complete genome of the Gram-negative beta-proteobacterium Chromobacterium violaceum has increasingly impacted our understanding of this microorganism. This review focuses on the genomic organization and structural analysis of the deduced proteins of the chemosensory adaptation system of C. violaceum. C. violaceum has multiple homologues of most chemotaxis genes, organized mostly in clusters in the bacterial genome. We found at least 67 genes, distributed in 10 gene clusters, involved in the chemotaxis of C. violaceum. A close examination of the chemoreceptors methyl-accepting chemotaxis proteins (MCPs), and the deduced sequences of the members of the two-component signaling system revealed canonical motifs, described as essential for the function of the deduced proteins. The chemoreceptors found in C. violaceum include the complete repertoire of such genes described in bacteria, designated as tsr, tar, trg, and tap; 41 MCP loci were found in the C. violaceum ...

BMC Microbiology, 2015

Background: Despite being important thermal dimorphic fungi causing Paracoccidioidomycosis, the p... more Background: Despite being important thermal dimorphic fungi causing Paracoccidioidomycosis, the pathogenic mechanisms that underlie the genus Paracoccidioides remain largely unknown. Microbial pathogens express molecules that can interact with human plasminogen, a protein from blood plasma, which presents fibrinolytic activity when activated into plasmin. Additionally, plasmin exhibits the ability of degrading extracellular matrix components, favoring the pathogen spread to deeper tissues. Previous work from our group demonstrated that Paracoccidioides presents enolase, as a protein able to bind and activate plasminogen, increasing the fibrinolytic activity of the pathogen, and the potential for adhesion and invasion of the fungus to host cells. By using proteomic analysis, we aimed to identify other proteins of Paracoccidioides with the ability of binding to plasminogen. Results: In the present study, we employed proteomic analysis of the secretome, in order to identify plasminogen-binding proteins of Paracoccidioides, Pb01. Fifteen proteins were present in the fungal secretome, presenting the ability to bind to plasminogen. Those proteins are probable targets of the fungus interaction with the host; thus, they could contribute to the invasiveness of the fungus. For validation tests, we selected the protein fructose 1,6-bisphosphate aldolase (FBA), described in other pathogens as a plasminogen-binding protein. The protein FBA at the fungus surface and the recombinant FBA (rFBA) bound human plasminogen and promoted its conversion to plasmin, potentially increasing the fibrinolytic capacity of the fungus, as demonstrated in fibrin degradation assays. The addition of rFBA or anti-rFBA antibodies was capable of reducing the interaction between macrophages and Paracoccidioides, possibly by blocking the binding sites for FBA. These data reveal the possible participation of the FBA in the processes of cell adhesion and tissue invasion/ dissemination of Paracoccidioides. Conclusions: These data indicate that Paracoccidioides is a pathogen that has several plasminogen-binding proteins that likely play important roles in pathogen-host interaction. In this context, FBA is a protein that might be involved somehow in the processes of invasion and spread of the fungus during infection.

In this paper we focused on the experiences of ageing from the perspective of elderly people. Our... more In this paper we focused on the experiences of ageing from the perspective of elderly people. Our main aims were to explore their perceptions and representations about the ageing experience and to analyse if their conceptions are closer to positive social representations of active ageing or to ageist social assumptions. Thirty-five females (mean age of 80 years) and seven males (mean age of 73 years) participated in this study, recruited in a network of institutions run by the city council of Setubal. Data collection was conducted with structured interviews and the obtained transcriptions were submitted to qualitative thematic analysis. With this analytic approach it was possible to identify dominant themes in participants' discourses. Results show that elderly perceive and represent the process of ageing according to a binary perspective, displaying both positive and negative dimensions. Even if the ageing experience is described according to a positive perspective, it is also anchored on ageist social constructions. Thus the positive social representations of ageing expressed through active ageing discourses are still not fully assimilated and integrated on people's self-perceptions and identities.