Virulence Factors IN Fungi of Systemic Mycoses

Fatores de virulência em fungos de micoses sistêmicaFungos patogênicos causadores de micoses sistêmicas possuem vários fatores que permitem seu crescimento nas condições adversas oferecidas pelo hospedeiro, propiciando o estabelecimento da relação parasitária e contribuindo no processo de doença. Esses fatores são conhecidos como fatores de virulência auxiliando no desenvolvimento da infecção e interferindo com a patogênese das micoses. O presente trabalho avalia os fatores de virulência em fungos patogênicos como Blastomyces dermatitidis, Coccidioides immitis, Cryptococcus neoformans, Histoplasma capsulatum e Paracoccidioides brasiliensis, em relação à termotolerância, dimorfismo, componentes da parede celular ou cápsula, bem como a produção de enzimas. Os fatores de virulência auxiliam na aderência, colonização, disseminação e habilidade do fungo para resistir a ambientes hostis e escapar dos mecanismos da resposta imune do hospedeiro.Tanto os fatores de virulência apresentados por diferentes fungos, como os mecanismos de defesa oferecidos pelo hospedeiro requerem ação e interação de processos complexos, cujo conhecimento permitirá a melhor compreensão da patogenia das micoses sistêmicas.

Avaliação de fontes de amônia para o tratamento de fenos de gramíneas tropicais. 1. Constituintes da parede celular, poder tampão e atividade ureática

Avaliaram-se as alterações da fração fibrosa e as características químicas dos fenos de braquiária decumbens (Brachiaria decumbnes Stapf) e jaraguá (Hyparrhenia rufa Ness Stapf) não-tratados, tratados com uréia (U-5,4% da MS), uréia (UL-5,4% da MS) mais labe-labe (Lablab purpureus L. Sweet, cv. Highworth-3,0% da MS) ou amônia anidra (NH3 -3,0% da MS). O tratamento químico com uréia ou NH3 aumentou o pH e a digestibilidade in vitro verdadeira dos fenos. A amonização não alterou os teores de fibra em detergente ácido e celulose, mas diminuiu os de fibra em detergente neutro, hemicelulose e lignina. O uso do labe-labe como fonte adicional de urease não aumentou a eficiência da uréia no tratamento dos volumosos. As avaliações do conteúdo de umidade, do poder tampão e da atividade ureática são técnicas que podem auxiliar na previsão das respostas dos volumosos à amonização com o uso de uréia.

Perfil químico da parede celular e suas implicações na digestibilidade de Brachiaria brizantha e Brachiaria humidicola

No presente trabalho foram determinadas a composição química e a digestibilidade de diversas frações de Brachiaria brizantha e Brachiaria humidicola, após 70 dias de crescimento. O delineamento experimental foi inteiramente casualizado com cinco repetições para cada espécie. As plantas coletadas foram subdivididas nas frações apical, mediana e basal para as folhas e mediana e basilar para caules, de acordo com sua localização. Foram determinadas as concentrações de fibra em detergente neutro (FDN), proteína bruta (PB), lignina, ácido p_cumárico, ácido ferúlico e açúcares neutros (glicose, xilose e arabinose) e a digestibilidade in situ após 48 horas de período de incubação ruminal. As diferentes frações das espécies estudadas apresentam distinta composição química, cujos efeitos são observados na digestibilidade. A B. brizantha apresentou maiores concentrações de FDN no caule e PB nas folhas. Isto resultou em coeficientes de digestibilidade maiores em relação à B. humidicola. A diferença de digestibilidade entre caule e folhas e nas frações mais velhas pode estar relacionada ao tipo de condensação da lignina presente nos tecidos. Evidências na concentração e na proporção dos ácidos p_cumárico e ferúlico sugerem esta relação. A concentração de ácidos fenólicos esteve relacionada com a digestibilidade da matéria seca e a lignina com a digestibilidade da FDN. A análise dos ácidos fenólicos pode se constituir em importante ferramenta para avaliar o grau de condensação da lignina na parede celular dos diferentes tecidos das plantas forrageiras. A concentração de açúcares neutros não apresentou um padrão definido na composição dos diferentes tecidos. A arabinose foi o único açúcar que apresentou relações com a digestibilidade da matéria seca e com a concentração de ácidos fenólicos.

Estreptomicina aumenta a aderência em células epiteliais de Bacteroides melaninogenicus associado às lesões peridentárias da cara inchada dos bovinos

Cara inchada of cattle (CI) is a periodontitis which occurs in calves in several regions of Brazil. Its progressive lesions, caused mainly by Bacteroides melaninogenicus and Actinomyces pyogenes, could lead to loss of teeth, malnutrition and possibly death of affected animals. For further analysis of the pathogenesis of this disease the influence of streptomycin on the adherence of the causative bacteria to oral epithelial cells of cattle was determined. Production of streptomycin by soil bacteria (Actinomycetes) in Brazil had been suggested by several authors. In our studies, streptomycin in subinibitory concentrations increased tenfold the rate of adherence with B. melaninogenicus (from 0.4 to 4.0 bacteria per bovine epithelial cell). On the contrary, streptomycin did not influence significantly the adherence of A. pyogenes nor streptococci of the viridans group. Thus, streptomycin could be a contributing factor to the development of the periodontal infections with B. melaninogenicus.

Aderência e formação do biofilme por Staphylococcus aureus ao polietilenotereftalato (PET) usado como embalagem para acondionamento de medicamentos e cosméticos

The polyethylene terephthalate (PET) is used for package drugs and cosmetics. The aim of this research was examine by scanning electron microscopy (SEM) a Staphylococcus aureus attachment and biofilm formation on a polyethylene terephthalate (PET) surface and hydrophobicity of S. aureus by adherence to hydrocarbons. A suspension of S. aureus was prepared in Mueller-Hinton broth and, coupons of polyethylene terephthalate were incubated for 30 minutes, two, 24 and 48 hours, 15 and 30 days. Afteron the coupons were removed and prepared for scanning electron microscope analysis. The attachment and biofilm formation was observed on the surfaces of PET. The SEM revealed adhesion and biofilm formation on PET surfaces. The hydrophobicity test classified S. aureus as hydrophobic.

eIF5A: Uma proteína essencial para a viabilidade celular cuja função permanece obscura

The putative translation initiation factor 5A (eIF5A) is a highly abundant and conserved protein in all eukaryotes and archaebacteria. This factor is essential for cell viability and is the only cellular protein known to contain the unusual amino acid residue hypusine. In Saccharomyces cerevisiae eIF5A is expressed in aerobic conditions by the gene TIF51A. Although eIF5A has been known for almost 30 years, the biological role of this protein is still obscure. This article reviews the research on the function of eIF5A, discussing the evidence for its involvement in various steps of mRNA metabolism, including translation initiation, nucleocytoplasmic transport and mRNA decay. Moreover, it indicates other studies that have associated eIF5A with cell proliferation and cell cycle progression. Finally, this review presents recent results obtained in our laboratory that reemphasize the role of eIF5A in the translation scenario. Further experiments will be necessary to define the role played by eIF5A in the translational machinery.

Proliferação celular nos linfomas caninos

Lymphoma studies deals with morphological classification and immunophenotypic features and they have to be amplified for cellular kinetics evaluation. This evaluation can only be safely made, when the proliferative index are evaluated. In men the proliferation index have, most of the time, important influence in the neoplasia prognosis and treatment In this work it was used 40 canine lymphomas that were classified according to Kiel methods and immunophenotype was achieved with CD3 (T lymphocyte) and CD79a (B lymphocyte). Cellular proliferation was evaluated by AgNORs and Ki-67 (MIB-1) According to Kiel classification system, high grade lymphomas were more frequent and T and B lymphoma showed the same frequency.When cellular proliferation was evaluated, there was a significant difference between high grade and low grade lymphomas by AgNOR and Ki-67 (MIB-1) methods, but did not differ when comparing immunophenotype. Among high grade malignancy lymphomas the NORs medium number per cell nucleoli was 1.37± 0.32 and in low grade was 0.98± 0.36, concerning Ki-67 the positive cellular percentual was 43.19% ± 19.01, e 14.09% ± 11.74 in high and low grade, respectively.

Polissacarídeos de parede celular fúngica: purificação e caracterização

The cell wall is a rigid structure essential for the survival of fungi. A knowledge of its composition is therefore useful for the development of novel anti-fungal drugs. In this context, polysaccharides as main components of the fungal cell wall have been the subject of intense scientific study over the years. The information gained from the knowledge of the structure of these macrobiomolecules could therefore be valuable in elucidating the mechanisms of their biosynthesis in the cell walls of pathogenic fungi infecting plants and animals alike. Determination of the chemical structures of these polysaccharides (endo) is preceded by their extraction and purification. The extractions, generally lead to neutral and/ or alkaline soluble biopolymers in groups according to their solubilities. Mixtures of polysaccharides in these extracts can then be purified by a combination of chemical and chromatographic methods. Following purification, the polysaccharides, considered homogeneous, can be characterized structurally using conventional techniques of carbohydrate chemistry, such as hydrolysis, methylation analysis, and FT-IR, 13C- and 1H- NMR spectroscopy. This review surveys the main scientific literature that characterizes polysaccharides constituting the fungal cell wall.

Lipoperoxidação, perda de viabilidade celular e diminuição da liberação de IL-8 de neutrófilos humanos na presença de corpos cetônicos

Type-1 diabetes patients suffer from frequent episodes of acidosis caused by an increased fatty acid metabolism and consequently increased plasma level of acetoacetate (AcAc) and β-hydroxybutyrate (β-HOB). This article describes a study of the effects of pathological concentrations of AcAc and β-HOB on lipoperoxidation, cell viability and the release of the CXCL8 (IL-8) cytokine by activated neutrophils. Neutrophils from healthy donors were isolated by density gradient (Histopaque® 1077/1119) and incubated with the ketone bodies. Lipoperoxidation was determined as thiobarbituric acid reactive substances (TBARS). The cell viability was evaluated by the release of intracellular lactate dehydrogenase. The release of CXCL8 was measured by ELISA in a 24-h culture of opsonized zymosan-stimulated neutrophils. AcAc, but not β-HOB, provoked a dose-dependent increase in the neutrophil membrane lipoperoxidation (p<0.05; r =0.9915). In the cytotoxicity assay, a dose-dependent release of LDH was observed when the neutrophils were incubated with AcAc in concentrations up to 40 mM (p<0.05). β-HOB was devoid of effect. The release of CXCL8 was inhibited by AcAc and β-HOB in a dose-dependent manner. In conclusion, these results suggest that the accumulation of ketone bodies in diabetic patients could be involved in their usually increased susceptibility to infection.

Organização celular dos testículos em Hylidae e leptodactylidae, no Pantanal (Estado do Mato Grosso do Sul, Brasil)

The objective of this work was to make a comparative analysis of germ cell organization at different stages of cellular differentiation in adult males of Dendropsophus nanus (Boulenger, 1889), Pseudis limellum (Cope, 1862), P. paradoxa (Linnaeus, 1758), and Scinax acuminatus (Cope, 1862), belonging to the family Hylidae; and Leptodactylus chaquensis (Cei, 1950) and L. podicipinus (Cope, 1862), belonging to the family Leptodactylidae, collected in the Pantanal and in Serra da Bodoquena, Mato Grosso do Sul State, Brazil. The testes were removed and fixed, dehydrated in a graded series of ethanol and embedded in methacrylate glycol resin (Historesin Leica®). The sections were stained by 1% toluidine blue and observed under light microscope. It was detected that all individual of the Hylidae family show, throughout the year, the presence of all germ cell types of spermatogenesis. However, all Leptodactylidae family individuals only show the presence of all germ cell types during the rainy season. The variations of characteristics in seminiferous epithelium organization, as well as the evident difference in the amount of spermatozoa inside the tubules, are evidence that the anurans in this work show different forms of spermatogenesis development throughout the year: the cycle is continuous for the Hylidae family, and discontinuous with explosive release of spermatozoa for the Leptodactylidae family.

Avaliação microbiológica da superfície dos implantes ortopédicos metálicos usados para fixar fraturas ósseas

In the majority of cases of bone fracture requiring surgery, orthopedic implants (screw-plate and screw) are used for osteosynthesis and the infections associated with such implants are due to the growth of microorganisms in biofilms. The objective of this study was to identify microorganisms recovered from osteosynthesis implants used to fix bone fractures, to assess the viability of the cells and the ability of staphylococci to adhere to a substrate and to determine their sensitivity/resistance to antimicrobials. After surgical removal, the metal parts of austenitic stainless steel (ASTM F138/F139 or ISO NBR 5832-1/9) were transported to the Laboratory of Clinical Microbiology, washed in buffer and subjected to ultrasonic bath at 40±2 kHz for 5 minutes. The sonicated fluid was used to seed solid culture media and cell viability was assessed under the microscope by with the aid of a fluorescent marker. The production of extracellular polysaccharide by Staphylococcus spp. was investigated by means of adhesion to a polystyrene plate. The profile of susceptibility to antimicrobials was determined by the disk diffusion assay. The most frequently isolated bacteria included coagulase-negative Staphylococcus resistant to erythromycin, clindamycin and oxacillin. Less frequent were Pseudomonas aeruginosa resistant to trimethoprim/sulfamethoxazole and ampicillin, Acinetobacter baumannii resistant to ceftazidime, Enterobacter cloacae resistant to cephalothin, cefoxitin, cefazolin, levofloxacin and ciprofloxacin, Bacillus spp. and Candida tropicalis. The observation of slides by fluorescence microscope showed clusters of living cells embedded in a transparent matrix. The test for adherence of coagulase-negative Staphylococcus to a polystyrene plate showed that these microorganisms produce extracellular polysaccharide. In conclusion, the metal parts were colonized by bacteria related to orthopedic implant infection, which were resistant to multiple antibiotics.

Atividade mutagênica e ativadora da resposta imune celular induzidas por Byrsonima crassa Niedenzu e Byrsonima intermedia A.Juss. (Malpighiaceae)

Pós-graduação em Biociências e Biotecnologia Aplicadas à Farmácia - FCFAR

Efeito da alimentação e densidade de estocagem no desempenho zootécnico e perfil celular do hepatopâncreas do camarão-da-amazônia Macrobrachium amazonicum (Heller, 1862) (Crustacea, Palaemonidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Alocação de canais em sistemas de comunicação celular empregando algoritmo genético distribuído

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Monitoramento de dados via internet baseado em telefonia celular

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)