A New Topical Eye Drop Containing LyeTxI-b, A Synthetic Peptide Designed from A Lycosa erithrognata Venom Toxin, Was Effective to Treat Resistant Bacterial Keratitis.

Bacterial keratitis is an ocular infection that can lead to severe visual disability. Staphylococcus aureus is a major pathogen of the eye. We recently demonstrated the strong antimicrobial activity of LyeTxI-b, a synthetic peptide derived from a Lycosa erithrognatha toxin. Herein, we evaluated a topical formulation (eye drops) containing LyeTxI-b to treat resistant bacterial keratitis. Keratitis was induced with intrastromal injection of 4 × 105 cells (4 µL) in New Zealand female white rabbits. Minimum inhibitory concentration (MIC) and biofilm viability were determined. LyeTxI-b ocular toxicity was evaluated through chorioallantoic membrane and Draize tests. One drop of the formulation (LyeTxI-b 28.9 µmol/L +0.5% CMC in 0.9% NaCl) was instilled into each eye four times a day, for a week. Slit-lamp biomicroscopy analysis, corneal histopathological studies and cellular infiltrate quantification through myeloperoxidase (MPO) and N-acetylglucosaminidase (NAG) detection were performed. LyeTxI-b was very effective in the treatment of keratitis, with no signs of ocular toxicity. Planktonic bacteria MIC was 3.6 µmol/L and LyeTxI-b treatment reduced biofilm viability in 90%. LyeTxI-b eliminated bacteria and reduced inflammatory cellular activity in the eyes. Healthy and treated animals showed similar NAG and MPO levels. LyeTxI-b is a potent new drug to treat resistant bacterial keratitis, showing effective antimicrobial and anti-inflammatory activity.

Notable fibrolytic enzyme production by Aspergillus spp. isolates from the gastrointestinal tract of beef cattle fed in lignified pastures.

Fungi have the ability to degrade vegetal cell wall carbohydrates, and their presence in the digestive tract of ruminants can minimize the effects of lignified forage on ruminal fermentation. Here, we evaluated enzyme production by Aspergillus spp. isolates from the digestive tracts of cattle grazed in tropical pastures during the dry season. Filamentous fungi were isolated from rumen and feces by culture in cellulose-based medium. Ninety fungal strains were isolated and identified by rDNA sequence analysis, microculture, or both. Aspergillus terreus was the most frequently isolated species, followed by Aspergillus fumigatus. The isolates were characterized with respect to their cellulolytic, xylanolytic, and lignolytic activity through qualitative evaluation in culture medium containing a specific corresponding carbon source. Carboxymethyl cellulase (CMCase) activity was quantified by the reducing sugar method. In the avicel and xilan degradation test, the enzyme activity (EA) at 48 h was significantly higher other periods (P < 0.05). Intra- and inter-specific differences in EA were verified, and high levels of phenoloxidases, which are crucial for lignin degradation, were observed in 28.9% of the isolates. Aspergillus terreus showed significantly higher EA for avicelase (3.96 ±1.77) and xylanase (3.13 ±.091) than the other Aspergillus species at 48 h of incubation. Isolates AT13 and AF69 showed the highest CMCase specific activity (54.84 and 33.03 U mg-1 protein, respectively). Selected Aspergillus spp. isolates produced remarkable levels of enzymes involved in vegetal cell wall degradation, suggesting their potential as antimicrobial additives or probiotics in ruminant diets.

Bioactive endophytic fungi isolated from Caesalpinia echinata Lam. (Brazilwood) and identification of beauvericin as a trypanocidal metabolite from Fusarium sp.

Aiming to identify new sources of bioactive secondary metabolites, we isolated 82 endophytic fungi from stems and barks of the native Brazilian tree Caesalpinia echinata Lam. (Fabaceae). We tested their ethyl acetate extracts in several in vitro assays. The organic extracts from three isolates showed antibacterial activity against Staphylococcus aureus and Escherichia coli [minimal inhibitory concentration (MIC) 32-64 µg/mL]. One isolate inhibited the growth of Salmonella typhimurium (MIC 64 µg/mL) and two isolates inhibited the growth of Klebsiella oxytoca (MIC 64 µg/mL), Candida albicans and Candida tropicalis (MIC 64-128 µg/mL). Fourteen extracts at a concentration of 20 µg/mL showed antitumour activities against human breast cancer and human renal cancer cells, while two isolates showed anti-tumour activities against human melanoma cancer cells. Six extracts were able to reduce the proliferation of human peripheral blood mononuclear cells, indicating some degree of selective toxicity. Four isolates were able to inhibit Leishmania (Leishmania) amazonensis and one isolate inhibited Trypanosoma cruzi by at least 40% at 20 µg/mL. The trypanocidal extract obtained from Fusarium sp. [KF611679] culture was subjected to bioguided fractionation, which revealed beauvericin as the compound responsible for the observed toxicity of Fusarium sp. to T. cruzi. This depsipeptide showed a half maximal inhibitory concentration of 1.9 µg/mL (2.43 µM) in a T. cruzi cellular culture assay.

Bioactive endophytic fungi isolated from Caesalpinia echinata Lam. (Brazilwood) and identification of beauvericin as a trypanocidal metabolite from Fusarium sp.

Aiming to identify new sources of bioactive secondary metabolites, we isolated 82 endophytic fungi from stems and barks of the native Brazilian tree Caesalpinia echinata Lam. (Fabaceae). We tested their ethyl acetate extracts in several in vitro assays. The organic extracts from three isolates showed antibacterial activity against Staphylococcus aureus and Escherichia coli [minimal inhibitory concentration (MIC) 32-64 μg/mL]. One isolate inhibited the growth of Salmonella typhimurium (MIC 64 μg/mL) and two isolates inhibited the growth of Klebsiella oxytoca (MIC 64 μg/mL), Candida albicans and Candida tropicalis (MIC 64-128 μg/mL). Fourteen extracts at a concentration of 20 μg/mL showed antitumour activities against human breast cancer and human renal cancer cells, while two isolates showed anti-tumour activities against human melanoma cancer cells. Six extracts were able to reduce the proliferation of human peripheral blood mononuclear cells, indicating some degree of selective toxicity. Four isolates were able to inhibit Leishmania (Leishmania) amazonensis and one isolate inhibited Trypanosoma cruzi by at least 40% at 20 μg/mL. The trypanocidal extract obtained from Fusarium sp. [KF611679] culture was subjected to bioguided fractionation, which revealed beauvericin as the compound responsible for the observed toxicity of Fusarium sp. to T. cruzi. This depsipeptide showed a half maximal inhibitory concentration of 1.9 μg/mL (2.43 μM) in a T. cruzi cellular culture assay.

Vesicular-arbuscular-/ecto-mycorrhiza succession in seedlings of. Eucalyptus spp

A ocorrência de micorrizas arbusculares (AM) e ectomicorrizas (ECM) no mesmo sistema radicular foi observada quando Eucalyptus urophylla S.T. Blake, E. citriodora Hook F., E. grandis W. Hill ex Maiden, E. cloeziana F. Muell e E. camaldulensis Dehnh foram inoculadas simultaneamente com Glomus etunicatum Becker & Gederman and Pisolithus tinctorius (Per.) Cocker & Couch. A sucessão entre os dois fungos foi observada. De modo geral, o aumento da colonização ECM foi acompanhado de um decréscimo em AM. A inoculação simultânea resultou em percentagens de colonização diferenciadas das obtidas com a inoculação isolada. Pisolithus tinctorius beneficiou-se da inoculação simultânea com G. etunicatum. Para o fungo AM, o efeito positivo da inoculação simultânea ocorreu até aos 60 dias após a inoculação. A partir de 120 dias, a colonização das raízes por G. etunicatum diminuiu na presença de P. tinctorius. A proporção de AM e ECM variou com o tempo de avaliação e o total da percentagem de raízes colonizadas aproximou-se do valor máximo aos 60 dias da inoculação, mantendo-se constante. Os maiores valores foram observados para E. camaldulensis, seguido por E. citriodora, E. urophylla, E. grandis e E. cloeziana.

Avaliaçäo do risco de cárie através da determinaçäo do índice CEO-D e testes salivares (fluxo salivar e capacidade tampäo) em crianças com dentadura decídua na faixa etária de 3 a 6 anos de idade / Dental caries risk evaluation through CEO-D index determination and salivary tests (salivar flow and buffer capacity) in children with decidual dentition from 3 to 6 years old

Através da determinaçäo do índice CEO-D e testes salivares (fluxo salivar e capacidade tampäo), em crianças com dentadura decídua na faixa etária de 3 a 6 anos de idade, buscou-se a avaliaçäo do risco de cárie. Os resultados mostraram que quanto menor o fluxo salivar maior foi o índice CEO-D. Com relaçäo à capacidade tampäo e dados fornecidos pelo diário alimentar, näo foi possível uma correlaçäo com o índice de cárie