Optimization of lipids production by Cryptococcus laurentii 11 using cheese whey with molasses

This study aimed the optimization of culture condition and composition for production of Cryptococcus laurentii 11 biomass and lipids in cheese whey medium supplemented with sugarcane molasses. The optimization of pH, fermentation time, and molasses concentration according to a full factorial statistical experimental design was followed by a Plackett-Burman experimental design, which was used to determine whether the supplementation of the culture medium by yeast extract and inorganic salts could provide a further enhancement of lipids production. The following conditions and composition of the culture medium were found to optimize biomass and lipids production: 360 h fermentation, 6.5 pH and supplementation of (g L-1): 50 molasses, 0.5 yeast extract, 4 KH2PO4, 1 Na2HPO4, 0.75 MgSO4•7H2O and 0.002 ZnSO4•H2O. Additional supplementation with inorganic salts and yeast extract was essential to optimize the production, in terms of product concentration and productivity, of neutral lipids by C. laurentii 11. Under this optimized condition, the production of total lipids increased by 133% in relation to control experiment (from 1.27 to 2.96 g L-1). The total lipids indicated a predominant (86%) presence of neutral lipids with high content of 16- and 18- carbon-chain saturated and monosaturated fatty acids. This class of lipids is considered especially suitable for the production of biodiesel.

Different culture media containing methyldopa for melanin production by Cryptococcus species / Avaliação de diferentes meios de cultura contendo metildopa para a produção de melanina por espécies de Cryptococcus

INTRODUCTION: Melanin production by species of Cryptococcus is widely used to characterize C. neoformans complex in mycology laboratories. This study aims to test the efficacy of methyldopa from pharmaceutical tablet as a substrate for melanin production, to compare the production of melanin using different agar base added with methyldopa, and to compare the melanin produced in those media with that produced in Niger seed agar and sunflower seed agar by C. neoformans, C. laurentii, and C. albidus. Two isolates of each species, C. neoformans, C. laurentii, and C. albidus, and one of Candida albicans were used to experimentally detect conditions for melanin production. METHODS: The following media were tested: Mueller-Hinton agar (MHA), brain and heart infusion agar (BHIA), blood agar base (BAB), and minimal medium agar (MMA), all added with methyldopa, and the media Niger seed agar (NSA) and sunflower seed agar (SSA). RESULTS: All isolates grew in most of the culture media after 24h. Strains planted on media BAB and BHIA showed growth only after 48h. All isolates produced melanin in MMA, MHA, SSA, and NSA media. CONCLUSIONS: Methyldopa in the form pharmaceutical tablet can be used as a substrate for melanin production by Cryptococcus species; minimal medium plus methyldopa was more efficient than the BAB, MHA, and BHIA in the melanin production; and NSA and SSA, followed by MMA added with methyldopa, were more efficient than other media studied for melanin production by all strains studied.

INTRODUÇÃO: A produção de melanina por espécies de Cryptococcus é uma característica amplamente utilizada em laboratórios de micologia para caracterização do complexoC. neoformans. O objetivo deste estudo foi verificar a eficácia da metildopa na forma farmacêutica de comprimido, como substrato para a produção de melanina por Cryptococcus, comparar diferentes bases de meios de cultura acrescidas de metildopa para produção de melanina e comparar o pigmento produzido nestes meios com o produzido em ágar Níger e ágar girassol por C. neoformans, C. laurentii e C. albidus. MÉTODOS: Foram testados dois isolados de cada uma das espécies, C. neoformans, C.laurentii e C.albidus, e um de C. albicans para avaliar a produção de melanina nos meios de cultura ágar Müeller-Hinton (MH), ágar brain heart infusion (BHI), ágar base sangue (BS), meio mínimo (MM), todos acrescidos de metildopa, e ainda ágar girassol e ágar Níger. RESULTADOS: Todos os isolados cresceram na maioria dos meios após 24h. O crescimento nos meios BS e BHI somente ocorreu após 48h. Todos os isolados produziram melanina nos meios MM, MH, girassol e Niger. CONCLUSÕES: A metildopa de origem farmacêutica pode ser utilizada como substrato para a produção de melanina por espécies de Cryptococcus; o MM acrescido de metildopa mostrou-se mais eficiente na produção de melanina do que os meios BS, MH e BHI; ágar girassol e ágar Níger seguidos de MM acrescido de metildopa foram os mais eficientes na produção de melanina pelos isolados estudados.

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.