Galectin-1 exerts inhibitory effects during DENV-1 infection

Dengue virus (DENV) is an enveloped RNA virus that is mosquito-transmitted and can infect a variety of immune and non-immune cells. Response to infection ranges from asymptomatic disease to a severe disorder known as dengue hemorrhagic fever. Despite efforts to control the disease, there are no effective treatments or vaccines. In our search for new antiviral compounds to combat infection by dengue virus type 1 (DENV-1), we investigated the role of galectin-1, a widely-expressed mammalian lectin with functions in cell-pathogen interactions and immunoregulatory properties. We found that DENV-1 infection of cells in vitro exhibited caused decreased expression of Gal-1 in several different human cell lines, suggesting that loss of Gal-1 is associated with virus production. In test of this hypothesis we found that exogenous addition of human recombinant Gal-1 (hrGal-1) inhibits the virus production in the three different cell types. This inhibitory effect was dependent on hrGal-1 dimerization and required its carbohydrate recognition domain. Importantly, the inhibition was specific for hrGal-1, since no effect was observed using recombinant human galectin-3. Interestingly, we found that hrGal-1 directly binds to dengue virus and acts, at least in part, during the early stages of DENV-1 infection, by inhibiting viral adsorption and its internalization to target cells. To test the in vivo role of Gal-1 in DENV infection, Gal-1-deficient-mice were used to demonstrate that the expression of endogenous Galectin-1 contributes to resistance of macrophages to in vitro-infection with DENV-1 and it is also important to physiological susceptibility of mice to in vivo infection with DENV-1. These results provide novel insights into the functions of Gal-1 in resistance to DENV infection and suggest that Gal-1 should be explored as a potential antiviral compound.

Preferential consumption of larger fruits of Piper arboreum (Piperaceae) by Carollia perspicillata (Phyllostomidae) in the Brazilian tropical dry forest

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Antibacterial activity of alkyl gallates is a combination of direct targeting of FtsZ and permeabilization of bacterial membranes

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

Frugivores at higher risk of extinction are the key elements of a mutualistic network

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

Galectin-1 exerts inhibitory effects during DENV-1 infection

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Different extracts of Zingiber officinale decrease Enterococcus faecalis infection in Galleria mellonella

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

The receptor-like kinase SlSOBIR1 is differentially modulated by virus infection but its overexpression in tobacco has no significant impact on virus accumulation

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Sistema para depleção de proteínas em Xanthomonas citri subsp. citri

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Expressão gênica de Xanthomonas citri subsp. citri colonizando laranja doce ‘pêra rio’ (Citrus sinensis (L.) Osbeck) e lima ácida ‘galego’ (Citrus aurantifolia Swingle)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Mutagênese sítio-dirigida da ORF XAC0024 de Xanthomonas citri subsp. citri e suas implicações no desenvolvimento do cancro cítrico

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Nicotiana tabacum as an experimental host for the study of plant-Xylella fastidiosa interactions

Xylella fastidiosa causes citrus variegated chlorosis (CVC). Information generated from the X. fastidiosa genome project is being used to study the underlying mechanisms responsible for pathogenicity. However, the lack of an experimental host other than citrus to study plant-X. fastidiosa interaction has been an obstacle to accelerated progress in this area. We present here results of three experiments that demonstrated that tobacco could be an important experimental host for X. fastidiosa. All tobacco plants inoculated with a citrus strain of X. fastidiosa expressed unequivocal symptoms, consisting of orange leaf lesions, approximately 2 months after injection of the pathogen. CVC symptoms were observed in citrus 3 to 6 months after inoculation. The pathogen was readily detected in symptomatic tobacco plants by polymerase chain reaction (PCR) and phase contrast microscopy. In addition, X. fastidiosa was reisolated on agar plates in 4 of 10 plants. Scanning electron microscopy analysis of cross sections of stems and petioles revealed the presence of rod shaped bacteria restricted to the xylem of inoculated plants. The cell size was within the limit typical of X. fastidiosa.

In vitro antibacterial activity of medicinal plant extracts against Escherichia coli strains from human clinical specimens and interactions with antimicrobial drugs

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

Beta Diversity of Plant-Pollinator Networks and the Spatial Turnover of Pairwise Interactions

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

Interactions of Paracoccidioides brasiliensis with host cells: recent advances

Host-fungal interactions are inherently complex and dynamic. In order to identify new microbial targets and develop more effective anti-fungal therapies, it is important to understand the cellular and molecular mechanisms of disease. Paracoccidioidomycosis provokes a variety of clinical symptoms, and Paracoccidioides brasiliensis can reach many tissues, but primarily attacks the lungs. The ability of the pathogen to interact with the host surface structures is essential to further colonization, invasion, and growth. Epithelial cells may represent the first host barrier or the preferential site of entry of the fungus. For this reason, interactions between P. brasiliensis and Vero/A549 epithelial cells were evaluated, with an emphasis on the adherence, induction of cytoskeletal alterations, and differential signaling activity of the various surface molecules. The adhesion to and invasion of epithelial cells by P. brasiliensis may represent strategies employed to thwart the initial host immune response, and may help in the subsequent dissemination of the pathogen throughout the body.

Endophytic microorganisms from coffee tissues as plant growth promoters and biocontrol agents of coffee leaf rust

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