Differentiation and numerical analysis of oral yeasts based on SDS-Page profiles. Influence of the culture media on the whole-cell protein extracts

Antifungal activity of Annona crassiflora Mart. dichloromethane fraction against strains of C. albicans

Products derived from medicinal plants with antimicrobial activity are considered a promising alternative in the treatment of fungal infections. In this perspective, this study proposed to evaluate the antifungal activity of the dichloromethane fraction of Annona crassiflora Mart. against C. albicans strains. Tests were carried out to determine Minimum Inhibitory Concentration (MIC), Minimum Fungicide Concentration (MFC), microbial growth kinetics, fungal cell wall and membrane mechanisms of action, antifungal biofilm activity, and cytotoxic effects on human erythrocytes. The extract presented MIC and MFC values that ranged from 256 µg/mL to 1,024 µg/mL, with fungicidal activity in the microbial growth kinetics assay. The mechanism of action did not occur through damage to the cell wall or via binding to ergosterol in the membrane, though the fraction presents activity against biofilm and is not cytotoxic in human erythrocytes. The dichloromethane fraction of Annona crassiflora Mart. presented antifungal activity and reduced biofilm growth, without toxicity against human erythrocytes; however, further studies are needed to define its mechanism of action.

Evaluation of hollocelulase production by Lentinula edodes (Berk.) Pegler during the submerged fermentation growth using RSM

The cellulase proteins have a great importance in the enzymatic hydrolysis of woody biomass. Despite of costs being a major concern, it has been a stimulus to study basidiomycetes biochemical properties which degrade lignocellulosic material and have prompted the processes' study for obtaining cellulolytic enzymes in fungi. The objective of this research was to evaluate the effects of the initial nitrogen content on (ammonium sulfate) and on sugar cane bagasse, which hereby, acts as an inducer of hydrolytic enzymes to produce cellulases and xylanases, using three Lentinula edodes (Berk.) Pegler strains as a transformation agent. A factorial design with 22 replications in the central point was conducted, varying concentrations of ammonium sulfate and sugar cane bagasse. The submerged cultures carried out in synthetic culture medium and incubated at 25°C for 7 days on an orbital shaker at 150 rpm. The total protein and cellulase activity as endoglucanase, exoglucanase and β-glucosidase and the xylanase was also determined. The results showed that the production of hydrolytic enzymes was stimulated by the presence of high concentrations of sugar cane bagasse (30g/L), characterizing it as an inducer due to the demonstrated proportional relationship. Thus, ammonium sulfate acted as a reducing agent in the synthesis of enzymes, being the low concentrations (0.1g/L) indicated for the enzyme production system under study. Among the studied strains, the EF52 showed higher activity for xylanase, endoglucanases, β-glucosidase and also protein.

Antimicrobial potential of some plant extracts against Candida species

The increase in the resistance to antimicrobial drugs in use has attracted the attention of the scientific community, and medicinal plants have been extensively studied as alternative agents for the prevention of infections. The Candida genus yeast can become an opportunistic pathogen causing disease in immunosuppressive hosts. The purpose of this study was to evaluate dichloromethane and methanol extracts from Mentha piperita, Rosmarinus officinalis, Arrabidaea chica, Tabebuia avellanedae, Punica granatum and Syzygium cumini against Candida species through the analysis of Minimum Inhibitory Concentration (MIC). Results presented activity of these extracts against Candida species, especially the methanol extract.

Interpreting the SDS-PAGE protein patterns with self-organizing maps: application for the characterization of mosquito-pathogenic Bacillus strains

AIMS

To present the pairwise comparison of potential mosquito-pathogenic Bacillus strains based on their SDS-PAGE protein patterns and to evaluate their characteristic toxicity patterns.

METHODS AND RESULTS

In this work, 20 Bacillus strains were subjected to qualitative toxicity tests against Aedes aegypti and Culex quinquefasciatus larvae. The selected strains were then characterized by SDS-PAGE protein profiles. The highly heterogeneous multiple protein components of protein patterns were analysed using self-organizing map (SOM), a 'visualization and clustering' tool. Members of mosquitocidal Bacillus species were classified in four distinct clusters, and then toxicity patterns were examined. Cluster (1, 1) comprised of three highly toxic strains of Bacillus sphaericus: SPH88, 1593 and KSD-4; cluster (1, 2) consisted of two B. sphaericus strains: SSII-1 and Bsp-R that showed weak larvicidal activity; cluster (2, 1) constituted two B. sphaericus strains: WHO2297 and ISPC-5 that possessed moderate toxicity; and cluster (2, 2) contained four B. thuringiensis ssp. israelensis strains: ONR-60A, HD500, IPS70 and IPS82 belonging to serotype H14 but exhibited moderate to high mosquito larvicidal toxicity.

CONCLUSIONS

SOM served as a colour-coded alternate for easy visualization of similarities or dissimilarities between the strains even at the infra subspecies level. Furthermore, characteristic toxicity patterns of Bacillus strains of different clusters were determined.

SIGNIFICANCE AND IMPACT OF THE STUDY

Analysis of electrophoretic protein patterns using SOM provides a better insight into the inter-relationships of bacterial strains through similarity-based clustering and pairwise comparison of two strains.

Electrophoretic protein patterns and numerical analysis of Candida albicans from the oral cavities of healthy children

The aim of this research was to evaluate the protein polymorphism degree among seventy-five C. albicans strains from healthy children oral cavities of five socioeconomic categories from eight schools (private and public) in Piracicaba city, São Paulo State, in order to identify C. albicans subspecies and their similarities in infantile population groups and to establish their possible dissemination route. Cell cultures were grown in YEPD medium, collected by centrifugation, and washed with cold saline solution. The whole-cell proteins were extracted by cell disruption, using glass beads and submitted to SDS-PAGE technique. After electrophoresis, the protein bands were stained with Coomassie-blue and analyzed by statistics package NTSYS-pc version 1.70 software. Similarity matrix and dendrogram were generated by using the Dice similarity coefficient and UPGMA algorithm, respectively, which made it possible to evaluate the similarity or intra-specific polymorphism degrees, based on whole-cell protein fingerprinting of C. albicans oral isolates. A total of 13 major phenons (clusters) were analyzed, according to their homogeneous (socioeconomic category and/or same school) and heterogeneous (distinct socioeconomic categories and/or schools) characteristics. Regarding to the social epidemiological aspect, the cluster composition showed higher similarities (0.788 < S D < 1.0) among C. albicans strains isolated from healthy children independent of their socioeconomic bases (high, medium, or low). Isolates of high similarity were not found in oral cavities from healthy children of social stratum A and D, B and D, or C and E. This may be explained by an absence of a dissemination route among these children. Geographically, some healthy children among identical and different schools (private and public) also are carriers of similar strains but such similarity was not found among other isolates from children from certain schools. These data may reflect a restricted dissemination route of these microorganisms in some groups of healthy scholars, which may be dependent of either socioeconomic categories or geographic site of each child. In contrast to the higher similarity, the lower similarity or higher polymorphism degree (0.499 < S D < 0.788) of protein profiles was shown in 23 (30.6%) C. albicans oral isolates. Considering the social epidemiological aspect, 42.1%, 41.7%, 26.6%, 23.5%, and 16.7% were isolates from children concerning to socioeconomic categories A, D, C, B, and E, respectively, and geographically, 63.6%, 50%, 33.3%, 33.3%, 30%, 25%, and 14.3% were isolates from children from schools LAE (Liceu Colégio Albert Einstein), MA (E.E.P.S.G. "Prof. Elias de Melo Ayres"), CS (E.E.P.G. "Prof. Carlos Sodero"), AV (Alphaville), HF (E.E.P.S.G. "Honorato Faustino), FMC (E.E.P.G. "Prof. Francisco Mariano da Costa"), and MEP (E.E.P.S.G. "Prof. Manasses Ephraim Pereira), respectively. Such results suggest a higher protein polymorphism degree among some strains isolated from healthy children independent of their socioeconomic strata or geographic sites. Complementary studies, involving healthy students and their families, teachers, servants, hygiene and nutritional habits must be done in order to establish the sources of such colonization patterns in population groups of healthy children. The whole-cell protein profile obtained by SDS-PAGE associated with computer-assisted numerical analysis may provide additional criteria for the taxonomic and epidemiological studies of C. albicans.