Protection levels of vaccinated pigeons (Columba livia) against a highly pathogenic newcastle disease virus strain

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

Adhesion of Histoplasma capsulatum to pneumocytes and biofilm formation on an abiotic surface

The pathogenic fungus, Histoplasma capsulatum, causes the respiratory and systemic disease 'histoplasmosis'. This disease is primarily acquired via inhalation of aerosolized microconidia or hyphal fragments of H. capsulatum. Evolution of this respiratory disease depends on the ability of H. capsulatum yeasts to survive and replicate within alveolar macrophages. It is known that adhesion to host cells is the first step in colonization and biofilm formation. Some microorganisms become attached to biological and non-biological surfaces due to the formation of biofilms. Based on the importance of biofilms and their persistence on host tissues and cell surfaces, the present study was designed to investigate biofilm formation by H. capsulatum yeasts, as well as their ability to adhere to pneumocyte cells. H. capsulatum biofilm assays were performed in vitro using two different clinical strains of the fungus and biofilms were characterized using scanning electron microscopy. The biofilms were measured using a 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium-hydroxide (XTT) reduction assay. The results showed that both the H. capsulatum strains tested were very efficient at adhering to host cells and forming biofilm. Therefore, this is a possible survival strategy adopted by this fungus.

The adaptive potential of a plant pathogenic fungus, Rhizoctonia solani AG-3, under heat and fungicide stress

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Evaluation of pathogenic fungi occurrence in traumatogenic structures of freshwater fish

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Clues to the presence of pathogenic fungi in certain environments

The presence of various pathogenic fungi in rather unsuspected hosts and environments has always attracted the attention of the scientific community. Reports on the putative role of animals in fungal infections of humans bear important consequences on public health as well as on the understanding of fungal ecology. Fungi are ubiquitous in nature and their great capacity for adaptation allows them to survive and indeed, to thrive, in plants, trees and other natural substrata. Nonetheless, we are just beginning to learn the significance that these diverse fungal habitats have on the increasing number of immunosuppressed individuals. The accidental or permanent presence of fungi in animals, plants, soils and watercourses should not be taken too lightly because they constitute the source where potential pathogens will be contracted. If those fungal habitats that carry the largest risks of exposure could be defined, if seasonal variations in the production of infectious propagules could be determined, and if their mode of transmission were to be assessed, it would be possible to develop protective measures in order to avoid human infection. Additionally, unsuspected avenues for the exploration of fungal survival strategies would be opened, thus enhancing our capacity to react properly to their advancing limits. This paper explores several ecological connections between human pathogenic fungi and certain animals, trees, waterways and degraded organic materials. The occurrence of such connections in highly endemic areas will hopefully furnish more precise clues to fungal habitats and allow the design of control programs aimed at avoiding human infection.

Imunidade inata da glândula mamária bovina: resposta à infecção

A imunidade na glândula mamária pode ser classificada, assim como em outros sistemas, em inata ou inespecífica e adaptativa ou específica. A imunidade inata é a defesa predominante durante os estágios iniciais da infecção. As respostas inespecíficas estão presentes no local da infecção ou são ativadas rapidamente por numerosos estímulos e não aumentam pela exposição repetida ao mesmo agente etiológico. O primeiro obstáculo enfrentado por um patógeno para adentrar o úbere é composto pela barreira formada pelo esfíncter do teto e pelo tampão de queratina formado pelo epitélio queratinizado. Uma vez que o microrganismo tenha atravessado o canal do teto e alcançado a cisterna mamária, passam a atuar diversos fatores solúveis e celulares. Dentre os fatores solúveis, estão presentes: lactoperoxidase, sistema complemento, citocinas, lactoferrina, lisozima e NAGase. As defesas celulares inespecíficas na glândula mamária são representadas pelos neutrófilos, pelos macrófagos e pelas células natural killer. Na medida em que esses mecanismos funcionam adequadamente, a maioria dos patógenos será rapidamente eliminada antes que o sistema imune específico seja ativado, sem resultar em alterações na quantidade ou qualidade do leite produzido. Uma melhor compreensão sobre os mecanismos de defesa da glândula mamária e suas alterações durante os períodos críticos da infecção é imprescindível para o desenvolvimento de métodos mais eficazes de profilaxia e controle da mastite, a principal doença dos ruminantes leiteiros. O presente estudo revisou os principais aspectos responsáveis pelo desenvolvimento da imunidade inata na glândula mamária bovina.

Retention of oral microorganisms on conventional and resin-modified glass-ionomer cements

A cárie secundária representa problema de saúde pública e socioeconômico no mundo. A restauração de dentes acometidos por cárie pode criar condições favoráveis à proliferação microbiana na superfície do material restaurador ou na interface dente/restauração, criando ambiente propício para o estabelecimento de cárie secundária. O objetivo deste estudo foi avaliar a capacidade de retenção de placa bacteriana em cimentos de ionômero de vidro convencionais (Chelon-Fil e Vidrion R) e modificados por resina (Vitremer e Fuji II LC) e de resina composta híbrida (Z100), utilizada como controle. Nos testes de retenção de microrganismos, in situ, 12 voluntários utilizaram, por 7 dias, placa de Hawley contendo corpos-de-prova de todos os materiais. A seguir, os corpos-de-prova foram transferidos para tubos contendo 2,0 ml de Ringer-PRAS e os microrganismos presentes em sua superfície foram cultivados em placa com ágar-sangue e ágar Mitis Salivarius Bacitracina, os quais foram incubados, a 37ºC, em anaerobiose (90% N2, 10% CO2), por 10 e 2 dias, respectivamente. Os ionômeros modificados por resina retiveram quantidade de bactérias similar àquela mostrada pela resina testada. Os ionômeros modificados por resina também apresentaram menor número de estreptococos do grupo mutans do que a resina e os cimentos ionoméricos convencionais. Os ionômeros de vidro convencionais apresentaram menor número de estreptococos do grupo mutans que a resina, sendo que essa diferença não foi estatisticamente significativa.

Occurrence of yeasts, enterococci and other enteric bacteria in subgingival biofilm of HIV-positive patients with chronic gingivitis and necrotizing periodontitis

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

Photodynamic inactivation of microorganisms present on complete dentures. A clinical investigation

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

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.

Polymerase Chain Reaction Detection of Enterotoxins Genes in Coagulase-Negative Staphylococci Isolated from Brazilian Minas Cheese

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

Contribution of the Malpighian tubules for the maintenance of symbiotic microorganisms in cephalotes ants

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ileum of the Cephalotes ants: A specialized structure to harbor symbionts microorganisms

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)