Objectives: This research work intends to clarify the role of artificial saliva, in particularly the role of mucin, a salivary protein, on the surface properties and adhesion ability of Candida spp. oral clinical isol...Objectives: This research work intends to clarify the role of artificial saliva, in particularly the role of mucin, a salivary protein, on the surface properties and adhesion ability of Candida spp. oral clinical isolates to abiotic surfaces. Methods: Four oral clinical isolates of Candida spp. were used: two Candida albicans strains (AC;AM) and two Candida parapsilosis strains (AD;AM2). The strains were isolated from patients using oral prosthesis. The microorganisms were cultured in the absence or presence of mucin and artificial saliva, and their adhesion to an abiotic surface (coated with mucin and artificial saliva) was evaluated. Results: The presence of mucin per se onto the abiotic surface decreased the adhesion of all strains, although the combination of mucin with artificial saliva had reduced this effect. No direct correlation between adhesion and the surface free energies of adhesion of the microorganisms was found. Significance: Candida spp. were human commensal microorganisms that became pathogenic when the host immune defenses were compromised. Medical devices were colonized by Candida spp. particularly, oral prostheses, which might lead to the degradation of the prostheses and systemic infections. The salivary secretions that constantly cover the oral cavity influenced Candida spp. adhesion process. Therefore, it was important to understand the interactions between Candida spp., salivary proteins and the characteristic of oral prosthesis when developing materials for oral prostheses.展开更多
Microbial decomposers,especially a fungal group called aquatic hyphomycetes,play a critical role in processing plant litter in freshwaters by increasing its palatability to invertebrate shredders.Traditionally,communi...Microbial decomposers,especially a fungal group called aquatic hyphomycetes,play a critical role in processing plant litter in freshwaters by increasing its palatability to invertebrate shredders.Traditionally,communities of aquatic hyphomycetes have been assessed through the identification of spores,which misses non-sporulating taxa.Among new technologies,454 pyrosequencing stands out as most promising for large-scale species identification.However,very few attempts have been made to validate its effectiveness for assessing the diversity of stream-dwelling fungal communities.We attempted to gain greater insight into the diversity of aquatic fungal communities in streams exposed to various degrees of eutrophication by using the 454 pyrosequencing technology.A total of 173,889 ITS2 pyrosequencing reads with hits for fungi were obtained from the 5 investigated streams.The majority of operational taxonomic units(OTUs)belonged to Ascomycota and the identification to the genus level was achieved for 169 OTUs.Of the total,135,257 reads(ca.78%)showed close affinities to aquatic hyphomycete species.Pyrosequencing showed declining fungal diversity in the most eutrophic streams,which was congruent with a reduced diversity found through spore identification.Dominance patterns revealed by connecting representative OTUs to ITS sequences from aquatic hyphomycetes were similar to those determined by traditional spore identification techniques.However,454 pyrosequencing provided a more comprehensive view of fungal diversity;it captured almost twice as many taxa as spore counts.This study vali-dates the effectiveness of 454 pyrosequencing for surveying the diversity of stream-dwelling fungal decomposer communities.Its application may accelerate the use of these communities for monitoring the integrity of freshwaters.展开更多
文摘Objectives: This research work intends to clarify the role of artificial saliva, in particularly the role of mucin, a salivary protein, on the surface properties and adhesion ability of Candida spp. oral clinical isolates to abiotic surfaces. Methods: Four oral clinical isolates of Candida spp. were used: two Candida albicans strains (AC;AM) and two Candida parapsilosis strains (AD;AM2). The strains were isolated from patients using oral prosthesis. The microorganisms were cultured in the absence or presence of mucin and artificial saliva, and their adhesion to an abiotic surface (coated with mucin and artificial saliva) was evaluated. Results: The presence of mucin per se onto the abiotic surface decreased the adhesion of all strains, although the combination of mucin with artificial saliva had reduced this effect. No direct correlation between adhesion and the surface free energies of adhesion of the microorganisms was found. Significance: Candida spp. were human commensal microorganisms that became pathogenic when the host immune defenses were compromised. Medical devices were colonized by Candida spp. particularly, oral prostheses, which might lead to the degradation of the prostheses and systemic infections. The salivary secretions that constantly cover the oral cavity influenced Candida spp. adhesion process. Therefore, it was important to understand the interactions between Candida spp., salivary proteins and the characteristic of oral prosthesis when developing materials for oral prostheses.
基金Fund–Operational Competitiveness Programme(FEDER-POFC-COMPETE)(FCOMP-01-0124-FEDER-013954)the Portuguese Foundation for Science and Technology supported this study(PEst-OE/BIA/UI4050/2014 and PTDC/AACAMB/113746/2009)S.Duarte(SFRH/BPD/47574/2008).
文摘Microbial decomposers,especially a fungal group called aquatic hyphomycetes,play a critical role in processing plant litter in freshwaters by increasing its palatability to invertebrate shredders.Traditionally,communities of aquatic hyphomycetes have been assessed through the identification of spores,which misses non-sporulating taxa.Among new technologies,454 pyrosequencing stands out as most promising for large-scale species identification.However,very few attempts have been made to validate its effectiveness for assessing the diversity of stream-dwelling fungal communities.We attempted to gain greater insight into the diversity of aquatic fungal communities in streams exposed to various degrees of eutrophication by using the 454 pyrosequencing technology.A total of 173,889 ITS2 pyrosequencing reads with hits for fungi were obtained from the 5 investigated streams.The majority of operational taxonomic units(OTUs)belonged to Ascomycota and the identification to the genus level was achieved for 169 OTUs.Of the total,135,257 reads(ca.78%)showed close affinities to aquatic hyphomycete species.Pyrosequencing showed declining fungal diversity in the most eutrophic streams,which was congruent with a reduced diversity found through spore identification.Dominance patterns revealed by connecting representative OTUs to ITS sequences from aquatic hyphomycetes were similar to those determined by traditional spore identification techniques.However,454 pyrosequencing provided a more comprehensive view of fungal diversity;it captured almost twice as many taxa as spore counts.This study vali-dates the effectiveness of 454 pyrosequencing for surveying the diversity of stream-dwelling fungal decomposer communities.Its application may accelerate the use of these communities for monitoring the integrity of freshwaters.
