Adaptive Laboratory Evolution for Multistress Tolerance, including Fermentability at High Glucose Concentrations in Thermotolerant Candida tropicalis

Candida tropicalis, a xylose-fermenting yeast, has the potential for converting cellulosic biomass to ethanol. Thermotolerant C. tropicalis X-17, which was isolated in Laos, was subjected to repetitive long-term cultivation with a gradual increase in temperature (RLCGT) in the presence of a high concentration of glucose, which exposed cells to various stresses in addition to the high concentration of glucose and high temperatures. The resultant adapted strain demonstrated increased tolerance to ethanol, furfural and hydroxymethylfurfural at high temperatures and displayed improvement in fermentation ability at high glucose concentrations and xylose-fermenting ability. Transcriptome analysis revealed the up-regulation of a gene for a glucose transporter of the major facilitator superfamily and genes for stress response and cell wall proteins. Additionally, hydropathy analysis revealed that three genes for putative membrane proteins with multiple membrane-spanning segments were also up-regulated. From these findings, it can be inferred that the up-regulation of genes, including the gene for a glucose transporter, is responsible for the phenotype of the adaptive strain. This study revealed part of the mechanisms of fermentability at high glucose concentrations in C. tropicalis and the results of this study suggest that RLCGT is an effective procedure for improving multistress tolerance.

Microwave assisted extraction, phytochemical and antimicrobial evaluation of ethyl acetate extracts of stem bark of Ficus exasperata (Vahl)

Stem bark of Ficus exasperata was extracted using ethyl acetate by microwave-assisted solvent extraction. Phytochemical screening and antimicrobial evaluation were carried out on the extract. Phytochemical screening revealed the presence of cardiac glycosides, tannins, flavonoids, triterpenes and steroids. Antimicrobial evaluation revealed that the extract is active against Methicillin – resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Streptococcus pneumoniae, Salmonella typhi, Proteus mirabilis, Shigella dysenteriae, Candida stellatoidea and Candida tropicalis. The zones of inhibition (mm) for the test organisms were (24 - 31) mm. Minimum inhibition concentrations (mg/L) of extract against MRSA, Staphylococcus aureus, Streptococcus pneumonia, Salmonella typhi, Proteus mirabilis, Shigella dysenteriae, Candida stellatoidea and Candida tropicalis were 2.5, 1.25,1.25, 2.5, 1.25, 1.25, 1.25 and 2.5 respectively. Minimum bactericidal concentrations (mg/L) of extract against Methicillin – resistant Staphylococcus aureus (MRSA), Staphylococcus aureus, Streptococcus pneumonia, Salmonella typhi, Proteus mirabilis Shigella dysenteriae Candida stellatoidea and Candida tropicalis were 5, 2.5, 2.5, 5, 5, 2.5,2.5 and 5 respectively. The extract showed high inhibition against MRSA and Candida tropicalis.

Diversidade da microbiota de fungos da própolis in natura / Diversity of in natura propolis fungal microbiota

O presente estudo teve por objetivo realizar a identificação dos fungos encontrados na própolis produzido por Apis mellifera L. da Baía do Iguape, Brasil. Para tanto, foram utilizadas técnicas morfológicas, bioquímicas e moleculares, sendo averiguado o perfil de restrição gerado por espaçador interno transcrito (ITS1 e ITS4). O tamanho dos produtos de PCR foi analisado quanto ao perfil de restrição obtidos com endonuclease (HhaI, HaeIII e HinfI) por espécie. Foram identificadas dezesseis espécies de fungos filamentosos: Flavodon flavus, Aspergillus nomius, Aspergillus versicolor, Cladosporium sp., Coniothyrium sidae, Didymella sp., Paecilomyces variotii, Cladosporium cladosporioides, Penicillium citrinum, Fusarium incarnatum, Penicillium chermesinum, Phoma sp., Stagonosporopsis valerianellae, Phoma medicaginis, Paraphoma fimeti e Stagonosporopsis cucurbitacearum; e seis espécies de leveduras: Candida tropicalis, Candida guiliermondii, Candida famata, Kodomala ohmeri, Trichosporon asahiu e Cryptococcus laurentii. Stagonosporopsis cucurbitacearum e leveduras pertencentes ao gênero Candida foram os microrganismos de maior ocorrência nas amostras da própolis provenientes da Baía do Iguape, Brasil.

Atividade anti-Candida do extrato etanólico de Libidibia ferrea

Dentre as infecções fúngicas que acometem seres humanos, a candidíase apresenta muita relevância, tendo a Candida albicans como o agente etiológico mais comum. Porém, Candida parapsilosis e Candida tropicalis também têm emergido como causadoras de candidíase. Nativa da mata atlântica brasileira, a Libidibia ferrea é uma planta que tem sido estudada por sua capacidade de controle microbiológico. Portanto, o presente trabalho tem como objetivo avaliar a atividade antifúngica de L. ferrea sobre C. parapsilosis, C. albicans e C. tropicalis. A capacidade antifúngica dos extratos etanólicos de L. férrea foi analisada por meio do método de macrodiluição seriada, no qual identificou-se inibição na concentração máxima testada, a partir de 1,3% de rendimento do extrato. O teste de sensibilidade em placas mostrou inibição do crescimento de C. albicans e C. tropicalis na maior concentração testada, enquanto a inibição de C. parapsilosis foi observada de maneira dose-dependente a partir de 0,5mg/mL do extrato etanólico de L. ferrea. A capacidade antifúngica também foi avaliada por meio dos discos de difusão, dos quais não se observou inibição do crescimento de C. albicans, C. tropicalis e C. parapsilosis em nenhuma das concentrações realizadas. Além disso, foi realizado o teste de sinergismo entre o extrato e antifúngicos utilizados, observando ação sinérgica do extrato com fluconazol sobre as placas contendo C. parapsilosis, mas sem alterações sinérgicas ou antagônicas sob as demais espécies.

Synthesis of chalcone-based pyrimidine derivatives and their antimicrobial activity

A series of substituted chalcones and pyrimidine derivatives on their base was synthesized. Obtained compounds were tested for antimicrobial activity and ability to increase activity of known antimicrobial substances. Pyrimidine products shown good activity against Staphylococcus aureus and Candida tropicalis. These compounds also could increase activity of modified polyguanidines against Staphylococcus aureus.

Candida Tropicalis Spondylodiscits in an Immunocompetent Host: A Case Report and Literature Review

Background Fungal spondylodiscitis is not common but should be suspected in some cases. Candida tropicalis infections are being more frequently diagnosed due to some factors related to the microorganism. Case Description A C. tropicalis spondylodiscitis is described in a 72-year-old man who was treated with a combination of echinocandin (micafungin) and surgery. Conclusion The presence of some risk factors should promptly raise the suspicion of fungal spondylodiscitis. Treatment should be instituted as early as possible for the best outcome for the patient.