Inhibitory activity of compounds isolated from Polymnia sonchifolia on aflatoxin production by Aspergillus flavus

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

Production of bacteriocin-like inhibitory substances (BLIS) by Streptococcus salivarius strains isolated from the tongue and throat of children with and without sore throat

Cepas de Streptococcus salivarius, isoladas de crianças com e sem dor de garganta, foram testadas quanto à produção de bacteriocina contra Streptococcus pyogenes. Os resultados mostraram que as crianças que não tinham dor de garganta possuiam, na boca, cepas de bactérias produtoras de substâncias inibidoras semelhantes à bacteriocina contra S. pyogenes.

Purification and biochemical characterization of an endoxylanase from Aspergillus versicolor

An endoxylanase (beta-1,4-xylan xylanohydrolase, EC 3.2.1.8) was purified from the culture filtrate of a strain of Aspergillus versicolor grown on oat wheat. The enzyme was purified to homogeneity by chromatography on DEAE-cellulose and Sephadex G-75. The purified enzyme was a monomer of molecular mass estimated to be 19 kDa by SDS-PAGE and gel filtration. The enzyme was glycoprotein with 71% carbohydrate content and exhibited a pI of 5.4. The purified xylanase was specific for xylan hydrolysis. The enzyme had a K-m of 6.5 mg ml(-1) and a V-max of 1440 U (mg protein)(-1). (C) 1998 Federation of European Microbiological Societies. Published by Elsevier B.V. B.V. All rights reserved.

In vitro susceptibility testing of Microsporum gypseum isolated from healthy cattle and soil samples against itraconazole, terbinafine, fluconazole and topical veterinarian drugs

The present study evaluated in vitro susceptibility testing of dermatophytes isolates from healthy cattle and soil samples against three antifungal agents and three topical veterinarian drugs. Itraconazole and terbinafine showed a higher in vitro fungicidal activity than fluconazole. The veterinarian drugs LEPECID (R) and iodine 5% were more active in vitro than the UNGUENTO (R) spray. All drugs showed fungicidal activity against Microsporum gypseum, and they may be considered as efficient agents for the topical treatment of dermatophytoses in cattle.

An evaluation of the genetic diversity of Xylella fastidiosa isolated from diseased citrus and coffee in São Paulo, Brazil

Strains of Xylella fastidiosa, isolated from sweet orange trees (Citrus sinensis) and coffee trees (Coffea arabica) with symptoms of citrus variegated chlorosis and Requeima do Cafe, respectively, were indistinguish able based on repetitive extragenic palindromic polymerase chain reaction (PCR) and enterobacterial repetitive intergenic consensus PCR assays. These strains were also indistinguishable with a previously described PCR assay that distinguished the citrus strains from all other strains of Xylella fastidiosa. Because we were not able to document any genomic diversity in our collection of Xylella fastidiosa strains isolated from diseased citrus, the observed gradient of increasing disease severity from southern to northern regions of São Paulo State is unlikely due to the presence of significantly different strains of the pathogen in the different regions. When comparisons were made to reference strains of Xylella fastidiosa isolated from other hosts using these methods, four groups were consistently identified consistent with the hosts and regions from which the strains originated: citrus and coffee, grapevine and almond, mulberry, and elm, plum, and oak. Independent results from random amplified polymorphic DNA (RAPD) PCR assays were also consistent with these results; however, two of the primers tested in RAPD-PCR were able to distinguish the coffee and citrus strains. Sequence comparisons of a PCR product amplified from all strains of Xylella fastidiosa confirmed the presence of a CfoI polymorphism that can be used to distinguish the citrus strains from all others. The ability to distinguish Xylella fastidiosa strains from citrus and coffee with a PCR-based assay will be useful in epidemiological and etiological studies of this pathogen.

IMMUNOCYTOCHEMICAL DIFFERENTIATION OF REACTIVE HYPERPLASIA FROM FOLLICULAR LYMPHOMA USING MONOCLONAL-ANTIBODIES TO CELL-SURFACE AND PROLIFERATION-RELATED MARKERS

We tested the hypothesis that a panel of antibodies to cell surface, cytoplasmic, and nuclear antigens could reliably distinguish the cells composing reactive germinal centers from those composing follicular lymphoma. Immunocytochemistry was performed on deparaffinized sections of methacarn-fixed lymph node and tonsil (15 cases of reactive hyperplasia and 14 cases of follicular lymphoma) using antibodies to the nerve growth factor receptor (NGFR5), bcl-2 protein (124), proliferating cell nuclear antigen (PCNA; 19A2), and CD45RA (MT2). In 100% of cases of reactive hyperplasia, both MT2 and 124 showed positive immunostaining of mantle zone and scattered interfollicular lymphocytes, but in all cases there was a sharply demarcated absence of immunostaining of germinal center cells. However, diffuse immunostaining of follicular centers with MT2 (64%) and 124 (93%) and scattered intervening cells were seen in follicular lymphoma. The combination of antibodies to CD45RA and bcl-2 yielded positive immunostaining of follicular center cells in 93% of follicular lymphomas. The germinal center cells of reactive hyperplasia showed >75% nuclear positivity with antibodies to PCNA, in contrast to the follicular lymphoma cells, which showed variable PCNA indices ranging from 25 to >75%. A minority of follicular lymphoma cases (29%) showed PCNA indices comparable with those seen in cases of reactive hyperplasia. Antibodies to NGFR were positive in all cases of reactive hyperplasia and in 79% of cases of follicular hyperplasia, although the immunostaining intensity was generally decreased in follicular hyperplasia. In summary, antibodies to bcl-2 appear to be superior to those to CD45RA in distinguishing reactive hyperplasia from follicular lymphoma. Reactive hyperplasia cannot be discriminated from follicular hyperplasia using antibodies to PCNA or to nerve growth factor receptor.

Entomopathogens isolated from invasive ants and tests of their pathogenicity

Some ant species cause severe ecological and health impact in urban areas. Many attempts have been tested to control such species, although they do not always succeed. Biological control is an alternative to chemical control and has gained great prominence in research, and fungi and nematodes are among the successful organisms controlling insects. This study aimed to clarify some questions regarding the biological control of ants. Invasive ant species in Brazil had their nests evaluated for the presence of entomopathogens. Isolated entomopathogens were later applied in colonies of Monomorium floricola under laboratory conditions to evaluate their effectiveness and the behavior of the ant colonies after treatment. The entomopathogenic nematodes Heterorhabditis sp. and Steinernema sp. and the fungi Beauveria bassiana, Metarhizium anisopliae, and Paecilomyces sp. were isolated from the invasive ant nests. M. floricola colonies treated with Steinernema sp. and Heterorhabditis sp. showed a higher mortality of workers than control. The fungus Beauveria bassiana caused higher mortality of M. floricola workers. However, no colony reduction or elimination was observed in any treatment. The defensive behaviors of ants, such as grooming behavior and colony budding, must be considered when using fungi and nematodes for biological control of ants. Copyright © 2012 Maria Fernanda Miori de Zarzuela et al.

Anti-Candida targets and cytotoxicity of casuarinin isolated from Plinia cauliflora leaves in a bioactivity-guided study

In addition to the bio-guided investigation of the antifungal activity of Plinia cauliflora leaves against different Candida species, the major aim of the present study was the search for targets on the fungal cell. The most active antifungal fraction was purified by chromatography and characterized by NMR and mass spectrometry. The antifungal activity was evaluated against five Candida strains according to referenced guidelines. Cytotoxicity against fibroblast cells was determined. The likely targets of Candida albicans cells were assessed through interactions with ergosterol and cell wall composition, porosity and architecture. The chemical major component within the most active antifungal fraction of P. cauliflora leaves identified was the hydrolysable tannin casuarinin. The cytotoxic concentration was higher than the antifungal one. The first indication of plant target on cellular integrity was suggested by the antifungal activity ameliorated when using an osmotic support. The most important target for the tannin fraction studied was suggested by ultrastructural analysis of yeast cell walls revealing a denser mannan outer layer and wall porosity reduced. It is possible to imply that P. cauliflora targeted the C. albicans cell wall inducing some changes in the architecture, notably the outer glycoprotein layer, affecting the cell wall porosity without alteration of the polysaccharide or protein level. © 2013 by the authors.

Effect of divalent metal ions on the activity and stability of β-galactosidase isolated from Kluyveromyces lactis

In this study, it was demonstrated that β-galactosidase can be deactivated and reactivated with EDTA and divalent metal ions. The enzyme was deactivated after 20 minutes in EDTA solution. Maximal deactivation at the lowest EDTA concentration (10-3 mol.L-1) occurred in the presence of Tris-HCl buffer (pH 7.0). The enzyme recovered 50% of its initial activity after 10 minutes at Mg2+concentrations higher than 0.1 mmol.L-1. Experimental concentrations of 0.1 mmol.L-1 Mn2+ and 1.0 mmol.L-1 Co2+ were sufficient to reactivate the enzyme to around 300% of the control activity for the Mn2+ ion and nearly 100% for the Co2+ ion. The enzyme gradually lost its activity when the Co2+ concentration was 10-2 mol.L-1. Ni2+ and Zn2+ were unable to restore the catalytic activity. Km app and Vmax app were 1.95 ± 0.05 mmol.L-1 and 5.40 ± 0.86x10-2 mmol.min-1.mg-1, with o-NPG as substrate. Optimal temperature and pH were 34oC and 7.5. The half-life (t1/2) at 30°C was 17.5 min for the holoenzyme and 11.0 min for the apoenzyme. With respect to pH variation, the apoenzyme proved to be more sensitive than the holoenzyme. Keywords: β-galactosidase. Divalent metallic ions. Enzyme activity. Stability. RESUMO Efeito de íons metálicos divalentes na atividade e estabilidade da β-galactosidase isolada de Kluyveromyces lactis Este estudo demonstra como a β-galactosidase pode ser desativada e reativada usando EDTA e íons metálicos divalentes. A enzima foi desativada após 20 minutos na presença de EDTA. Desativação máxima para a menor concentração de EDTA (10-3 mol.L-1) ocorreu na presença do tampão Tris-HCl. A enzima recuperou 50% de sua atividade inicial após 10 minutos na presença de Mg2+ em concentrações superiores a 0,1mmol.L-1. Concentrações de 10-4 e 10-3mol.L-1 de Mn2+ e Co2+ foram suficientes para reativar a enzima em 300% comparado ao controle de íons Mn2+ e aproximadamente 100% para íons Co2+. A enzima perdeu gradualmente a sua atividade quando a concentração foi de 10-2 mol.L-1. Ni2+ e Zn2+ foram incapazes de restabelecer a atividade catalítica. Km app e Vmax app foram 1,95 ± 0,05 mmol.L-1 e 5,40 ± 0,86 x 10-2 mmol.min-1.mg-1. A temperatura e pH ótimos foram 34ºC e 7,5. A meia vida da holoenzima foi de 17,5 min a 30ºC e para a apoenzima foi de 11,0 min a 30ºC. Quanto à variação de pH, a apoenzima provou ser mais sensível que a holoenzima. Palavras-chave: β-galactosidase. Íons metálicos divalentes. Atividade enzimática. Estabilidade.

Healing Actions of Essential Oils from Citrus aurantium and d-Limonene in the Gastric Mucosa: The Roles of VEGF, PCNA, and COX-2 in Cell Proliferation

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

Multiplex-PCR for differentiation of Mycobacterium bovis from Mycobacterium tuberculosis complex

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

Differentiation of Haemonchus placei from Haemonchus contortus by PCR and by morphometrics of adult parasites and third stage larvae

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