Mauricio Ramírez-Castrillón

(GTG)5 MSP-PCR Fingerprinting as a Technique for Discrimination of Wine Associated Yeasts?

In microbiology, identification of all isolates by sequencing is still unfeasible in small research laboratories. Therefore, many yeast diversity studies follow a screening procedure consisting of clustering the yeast isolates using MSP-PCR fingerprinting, followed by identification of one or a few selected representatives of each cluster by sequencing. Although this procedure has been widely applied in the literature, it has not been properly validated. We evaluated a standardized protocol using MSP-PCR fingerprinting with the primers (GTG)5 and M13 for the discrimination of wine associated yeasts in South Brazil. Two datasets were used: yeasts isolated from bottled wines and vineyard environments. We compared the discriminatory power of both primers in a subset of 16 strains, choosing the primer (GTG)5 for further evaluation. Afterwards, we applied this technique to 245 strains, and compared the results with the identification obtained by partial sequencing of the LSU rRNA gene, considered as the gold standard. An array matrix was constructed for each dataset and used as input for clustering with two methods (hierarchical dendrograms and QAPGrid layout). For both yeast datasets, unrelated species were clustered in the same group. The sensitivity score of (GTG)5 MSP-PCR fingerprinting was high, but specificity was low. As a conclusion, the yeast diversity inferred in several previous studies may have been underestimated and some isolates were probably misidentified due to the compliance to this screening procedure.

Molecular Epidemiology of Agents of Human Chromoblastomycosis in Brazil with the Description of Two Novel Species

The human mutilating disease chromoblastomycosis is caused by melanized members of the order Chaetothyriales. To assess population diversity among 123 clinical strains of agents of the disease in Brazil we applied sequencing of the rDNA internal transcribed spacer region, and partial cell division cycle and β-tubulin genes. Strains studied were limited to three clusters divided over the single family Herpotrichiellaceae known to comprise agents of the disease. A Fonsecaea cluster contained the most important agents, among which F. pedrosoi was prevalent with 80% of the total set of strains, followed by 13% for F. monophora, 3% for F. nubica, and a single isolate of F. pugnacius. Additional agents, among which two novel species, were located among members of the genus Rhinocladiella and Cyphellophora, with frequencies of 3% and 1%, respectively.

Chromoblastomycosis caused by Rhinocladiella similis: Case report

We report a case of chromoblastomycosis in lesions on the chest and foot. Itraconazole was chosen as the initial treatment for this patient, who was followed up for 8 months before becoming noncompliant. The pathogenic fungal species was identified as Rhinocladiella similis by ITS region sequencing. In vitro analyses indicate that the fungus was sensitive to posaconazole and itraconazole. This report presents R. similis as a new agent of chromoblastomycosis and raises the hypothesis that this species could be more resistant to some antifungals than R. aquaspersa.

Environmental yeast communities in vineyards in the mountains of Santa Catarina State, Brazil

Yeasts were isolated from three vineyards located in the South Region of Brazil. A cross evaluation was carried out at the oldest vineyard of the study in Pinheiro Preto. Samples of grape berries, grapevine leaves and the soil, along with samples of the winery equipment and effluent, were collected. In the Serra do Marari and Campos Novos vineyards only samples of grape clusters were obtained. The 106 yeast isolates were identified by sequencing the D1/D2 domain of LSU rDNA or ITS1-5.8S-ITS2 region in 22 species. The values for the richness indices varied between the vineyards. A comparison of the taxonomic diversity of the yeasts from these regions using the reciprocal Simpson index showed a significant difference between the Serra do Marari and Campos Novos vineyards (5.72 ± 0.36 and 2.92 ± 0.36, respectively, p < 0.0001). The functional diversity was assessed in relation to the use of carbon and nitrogen sources by the yeasts isolated from each location. In general, we observed that the Pinheiro Preto and Campos Novos vineyards differed consistently from the Serra do Marari vineyard according to these indices (FAD2, FDc and Rao, p < 0.0001). The possible spreading of Saccharomyces cerevisiae from the winery to the vineyard in Pinheiro Preto was observed.

The Oleaginous Yeast Meyerozyma guilliermondii BI281A as a New Potential Biodiesel Feedstock: Selection and Lipid Production Optimization

A high throughput screening (HTS) methodology for evaluation of cellular lipid content based on Nile red fluorescence reads using black background 96-wells test plates and a plate reader equipment allowed the rapid intracellular lipid estimation of strains from a Brazilian phylloplane yeast collection. A new oleaginous yeast, Meyerozyma guilliermondii BI281A, was selected, for which the gravimetric determination of total lipids relative to dry weight was 52.38% for glucose or 34.97% for pure glycerol. The lipid production was optimized obtaining 108 mg/L of neutral lipids using pure glycerol as carbon source, and the strain proved capable of accumulating oil using raw glycerol from a biodiesel refinery. The lipid profile showed monounsaturated fatty acids (MUFA) varying between 56 or 74% in pure or raw glycerol, respectively. M. guilliermondii BI281A bears potential as a new biodiesel feedstock.

YEASTS: DIVERSITY IN KEFIR, PROBIOTIC POTENTIAL AND POSSIBLE USE IN ICE CREAM.

Kefir is a product made by the symbiotic fermentation of different microrganisms, resulting in a product with microbiological characteristics, physicochemical and sensory unparalleled. Bacterias, mainly of the gene Lactobacillus, and the yeasts are the main microrganisms that give rise of this product. The genres Kluyveromyces and Saccharomyces are the largest representatives of the yeasts found at Kefir’s microbiot. In relation of the probiotic potential of the yeasts, the one sold in drug form by mouth, is the Saccharomyces boulardii, however, researches are showing that other genres, other species and new strains of yeasts also had promising probiotic potential, but the researches don’t tell the application of this new probiotic yeasts in food. The aim of this review involved the achievement of a bibliographic review about different species and strains of yeasts found at Kefir’s samples by differents authors at the global level. The probiotic potential of yeasts was also studied, as well as the capability of probiotic microrganisms being added to ice cream. With conclusion it can be said that countless strains of yeasts are present in the Kefir’s symbiotic complex and, some of this possibly submit probiotic potential, that could being incorporated into ice cream, once the food have wide consumer acceptance and don’t uses the fermentation process in it’s preparation.