Genomic Analysis of Limosilactobacillus fermentum ATCC 23271, a Potential Probiotic Strain with Anti-Candida Activity.

Limosilactobacillus fermentum (ATCC 23271) was originally isolated from the human intestine and has displayed antimicrobial activity, primarily against Candida species. Complete genome sequencing and comparative analyses were performed to elucidate the genetic basis underlying its probiotic potential. The ATCC 23271 genome was found to contain 2,193,335 bp, with 2123 protein-coding sequences. Phylogenetic analysis revealed that the ATCC 23271 strain shares 941 gene clusters with six other probiotic strains of L. fermentum. Putative genes known to confer probiotic properties have been identified in the genome, including genes related to adhesion, tolerance to acidic pH and bile salts, tolerance to oxidative stress, and metabolism and transport of sugars and other compounds. A search for bacteriocin genes revealed a sequence 48% similar to that of enterolysin A, a protein from Enterococcus faecalis. However, in vitro assays confirmed that the strain has inhibitory activity on the growth of Candida species and also interferes with their adhesion to HeLa cells. In silico analyses demonstrated a high probability of the protein with antimicrobial activity. Our data reveal the genome features of L. fermentum ATCC 23271, which may provide insight into its future use given the functional benefits, especially against Candida infections.

Eugenol Induces Phenotypic Alterations and Increases the Oxidative Burst in Cryptococcus.

Eugenol is a phenolic compound and the main constituent of the essential oil of clove India. Although there are reports of some pharmacological effects of eugenol, this study is the first that proposes to evaluate the antifungal effects of this phenol against both Cryptococcus gattii and C. neoformans cells. The effect of eugenol against yeast cells was analyzed for drug susceptibility, alterations in cell diameter, capsule properties, amounts of ergosterol, oxidative burst, and thermodynamics data. Data demonstrated that there is no interaction between eugenol and fluconazole and amphotericin B. Eugenol reduced the cell diameter and the capsule size, increased cell surface/volume, changed positively the cell surface charge of cryptococcal cells. We also verified increased levels of reactive oxygen species without activation of antioxidant enzymes, leading to increased lipid peroxidation, mitochondrial membrane depolarization and reduction of lysosomal integrity in cryptococcal cells. Additionally, the results showed that there is no significant molecular interaction between eugenol and C. neoformans. Morphological alterations, changes of cellular superficial charges and oxidative stress play an important role in antifungal activity of eugenol against C. gattii and C. neoformans that could be used as an auxiliary treatment to cutaneous cryptococcosis.

Solid Flocculation and Emulsifying Activities of the Lipopolysaccharide Produced by Trichosporon mycotoxinivorans CLA2.

The objective of this study was to evaluate the capability of a lipopolysaccharide, produced by Trichosporon mycotoxinivorans CLA2 using residue of biodiesel processing, to flocculate two different solids in suspension. In addition, the emulsifying activity and the stability of this lipopolysaccharide in response to pH and temperature variations and in the presence of some electrolytes were evaluated. The lipopolysaccharide was used in concentrations ranging from 20 to 80 mgL-1 to flocculate 100 gL-1 of kaolin and 50 gL-1 of charcoal. The results indicated that the flocculating capability for each suspended particles reached 80 % and 78.79 % after 14 min, respectively. Other tests indicated that the emulsifying activity is weakly affected by temperature, pH and NaCl. In addition, the surfactant activity was assessed by the droplet diameter method and tension surface measurement. The surface tension of pure water decreased gradually with an increase in the biopolymer concentration until a minimum of 52 m Nm-1 with a CMC value of 4.54 mgL-1. These findings demonstrated a potential use of the bioemulsifier in flocculation and emulsification processes, which are also favored by its reduced toxicity compared to those of widely used commercial polymers.

Lactobacillus fermentum ATCC 23271 Displays In vitro Inhibitory Activities against Candida spp.

Lactobacilli are involved in the microbial homeostasis in the female genital tract. Due to the high prevalence of many bacterial diseases of the female genital tract and the resistance of microorganisms to various antimicrobial agents, alternative means to control these infections are necessary. Thus, this study aimed to evaluate the probiotic properties of well-characterized Lactobacillus species, including L. acidophilus (ATCC 4356), L. brevis (ATCC 367), L. delbrueckii ssp. delbrueckii (ATCC 9645), L. fermentum (ATCC 23271), L. paracasei (ATCC 335), L. plantarum (ATCC 8014), and L. rhamnosus (ATCC 9595), against Candida albicans (ATCC 18804), Neisseria gonorrhoeae (ATCC 9826), and Streptococcus agalactiae (ATCC 13813). The probiotic potential was investigated by using the following criteria: (i) adhesion to host epithelial cells and mucus, (ii) biofilm formation, (iii) co-aggregation with bacterial pathogens, (iv) inhibition of pathogen adhesion to mucus and HeLa cells, and (v) antimicrobial activity. Tested lactobacilli adhered to mucin, co-aggregated with all genital microorganisms, and displayed antimicrobial activity. With the exception of L. acidophilus and L. paracasei, they adhered to HeLa cells. However, only L. fermentum produced a moderate biofilm and a higher level of co-aggregation and mucin binding. The displacement assay demonstrated that all Lactobacillus strains inhibit C. albicans binding to mucin (p < 0.001), likely due to the production of substances with antimicrobial activity. Clinical isolates belonging to the most common Candida species associated to vaginal candidiasis were inhibited by L. fermentum. Collectively, our data suggest that L. fermentum ATCC 23271 is a potential probiotic candidate, particularly to complement candidiasis treatment, since presented with the best probiotic profile in comparison with the other tested lactobacilli strains.

Inhibition of Candida albicans CC biofilms formation in polystyrene plate surfaces by biosurfactant produced by Trichosporon montevideense CLOA72.

This study evaluated the effects of glycolipid-type biosurfactant produced by Trichosporon montevideense CLOA72 in the formation of biofilms in polystyrene plate surfaces by Candida albicans CC isolated from the apical tooth canal. Biofilm formation was reduced up to 87.4% with use of biosurfactant at 16 mg/ml concentration. It has been suggested that the interaction with the cell or polystyrene plate surface could ultimately be responsible for these actions. Therefore, the interaction of C. albicans CC cells with the biosurfactant, as well as the corresponding thermodynamic parameters, have been determined by isothermal titration calorimetry and zeta potential measurements. This process is endothermic (((int)H°=+1284±5 cal/mg OD(600)) occurring with a high increase of entropy (T((int)S°=+10635 cal/mg OD(600)). The caloric energy rate data released during the titulation indicates saturation of the cell-biosurfactant at 1.28 mg/ml OD(600). Also, the zeta potential of the cell surface was monitored as a function of the biosurfactant concentration added to cell suspension showing partial neutralization of net surface charge, since the value of zeta potential ranged from -16 mV to -6 mV during the titration. The changes of cell surface characteristics can contribute to the inhibition of initial adherence of cells of C. albicans in surface. The CMC of the purified biosurfactant produced from T. montevideense CLOA72 is 2.2 mg/ml, as determined both by ITC dilution experiments and by surface tension measurements. This biomolecule did not presented any cytotoxic effect in HEK 293A cell line at concentrations of 0.25-1 mg/ml. This study suggests a possible application of the referred biosurfactant in inhibiting the formation of biofilms on plastic surfaces by C. albicans.

Characterization of new biosurfactant produced by Trichosporon montevideense CLOA 72 isolated from dairy industry effluents.

The yeast strain CLOA 72 isolated from the effluent of a dairy industry in Brazil and identified as Trichosporon montevideense, was able to grow and produce a glycolipid biosurfactant when cultured on a mineral medium (MM) with sunflower oil as the carbon source. Biosurfactant production was partially growth-associated and maximal emulsification activity was observed at 144 h of cultivation (78.92%). The biosurfactant purified by precipitation with ethanol showed 78.66% emulsifying activity when used in concentrations above 4.5 mg/ml and was able to reduce the surface tension of water to values below 44.9 mN/m. The critical micellar concentration (CMC) was found to be 2.2 mg/ml. The highest emulsifying activity (E(24)) has been observed with vegetable oils, toluene, kerosene, isooctane, cyclohexane, hexane, diesel oil and hexadecane as compared to mineral oil and oleic acid. The biosurfactant also showed good stability during exposure to 100 degrees C for different periods of time (10 to 60 min), to high salinity (30% of NaCl, KCl and NaHCO(3)), and to a wide range of pH values (1-10). The biosurfactant purified by gel filtration chromatography is a glycolipid, with lipid portion containing 16.03% (9Z)-octadec-9-enoic acid, 14.92% hexadecanoic acid, and 9.63% (E) octadec-9-enoic acid and the carbohydrate portion containing mannose (35.29%), xylose (41.99%), arabinose (17.47%), and glucose (5.25%).

Phenol degradation by a Graphium sp. FIB4 isolated from industrial effluents.

In this work, we show that the fungal strain Graphium sp. FIB4 was able to use phenol as the sole carbon source. Higher degradation of phenol was accomplished by alginate-immobilized mycelial mass than by mycelial suspensions of Graphium sp. FIB4. Free mycelium exhibited higher degradation rates when compared with the alginate-immobilized mycelium in the presence of 14 mM of phenol or less. Above this concentration, degradation rates by free mycelium decreased and the immobilized mycelium showed higher values. The maximum degradation rate for 8 mM phenol was found to be 20.13 mg/l x h by free mycelia and 16.24 mg/l x h by immobilized mycelial mass in the presence of 18 mM phenol. When the fungus was grown on medium without phenol, catechol 1,2-dioxygenase activity was not detected. This enzyme activity was induced at phenol concentrations as low as 0.05 mM and up to 6 mM at 24 h incubation at 30 degrees C, suggesting that catechol was oxidized by the ortho type of ring fission. Addition of glucose reduced phenol consumption rate, and both substrates were used simultaneously. Glucose concentrations higher than 0.075% repressed the induction of phenol oxidation by Graphium sp. FIB4 grown on glucose. But glucose did not fully repress utilization of phenol by phenol-pre-induced cells. Immobilization and addition of calcium and barium ions were detrimental to the stability of catechol 1,2-dioxygenase activity and phenol degradation by Graphium sp. FIB4.