Growing Candida albicans Biofilms on Paper Support and Dynamic Conditions.

A stainless steel paper-embedded biofilm reactor (PEBR) was developed for Candida spp. growth, permitting confluent distribution of nutrients by capillary diffusion through ordinary laboratory filter paper. Antibiogram disks were distributed along the filter paper rim, and the PEBR received 0.1 or 0.01 % crystal violet (CV) at 200 µL min(-1) and at 37 °C, for 48 h. CV was recovered from the disks and measured at 540 nm. Candida albicans SC5314 cells were applied onto antibiogram disks. The bioreactor was assembled, and YEPD broth was admitted (200 µL min(-1)) at 37 °C, for 72 h. Biofilm growth was estimated via the MTT reduction test. Controls were disks that received the same treatments, except for the fungus. The PEBR was considered high-throughput table, low-cost, and feasible to grow C. albicans biofilms.

Anaerobic enhancement of protease secretion by periodontal Candida albicans strains / Aumento anaeróbio da secreção de protease pelas cepas de Candida albicans periodontal

Among other non-bacterial organisms, yeasts have been isolated from subgingival sites with relative frequency. Candida albicans is the species most commonly isolated although its role in periodontal disease has not been established. Objective: This study evaluated the secretion patterns of aspartyl-protease (Sap) by periodontal and nonperiodontal Candida albicans strains in normoxic and anoxic conditions. Material and methods: Periodontal strains (n=10; periodontal pockets ≥3.00 mm) and nonperiodontal Candida albicans strains (n=10) were grown under normoxic and anoxic conditions in protease-inducible broth. Sap activities were quantified in supernatants using azocasein as substrate. Whole-protein contents in supernatants were determined by Bradford’s method. Specific protease activities (Sap activity.protein-1) were assessed and compared. Results: While nonperiodontal strains secrete similar amounts of Sap under both atmospheric conditions, periodontal strains secrete reduced amounts in the presence of molecular oxygen. Conclusion: Despite the limited number of assayed isolates, the possibilities of adaptation or selection of candidal strains to periodontal microenvironment may be considered...

Entre organismos não bacterianos, as leveduras têm sido isoladas de sítios subgengivais com relativa frequência. Candida albicans é a espécie mais comumente isolada, embora seu papel na doença periodontal não esteja estabelecido. Objetivo: Este estudo avaliou os padrões de secreção de aspartil-protease (Sap) por cepas periodontais e não periodontais de Candida albicans em situações de normóxia e anóxia. Material e métodos: Cepas periodontais (n=10; bolsas periodontais ≥3,00 milímetros) e cepas de não periodontais (n=10) Candida albicans foram cultivadas sob condições normóxicas e anóxicas em caldo de protease-induzida. A atividade Sap foi quantificada em sobrenadantes utilizando azocaseína como substrato. O conteúdo de proteínas totais nos sobrenadantes foi determinado pelo método de Bradford. Atividades de protease específica (atividade de proteína Sap-1) foram avaliadas e comparadas. Resultados: Apesar das cepas não periodontais secre¬tarem quantidades semelhantes de Sap em ambas as condições atmosféricas, as cepas periodontais secretam quantidades reduzidas na presença de oxigênio molecular. Conclusão: Apesar do número limitado de amostras analisadas, as possibilidades de adaptação ou seleção de cepas de Candida no microambiente periodontal pode ser considerada...

Virulence modulation of Streptococcus mutans biofilms by metal ions released from orthodontic appliances.

OBJECTIVES: To evaluate the impact of metal ions commonly shed from orthodontic appliances on the virulence of Streptococcus mutans ATCC®25175™ biofilms. MATERIALS AND METHODS: Biofilms were grown in the presence of Ni(2+), Fe(3+), Cr(3+), Co(2+), and a metal ion pool at concentrations similar to those released in saliva of orthodontic patients for 72 hours. Once mature, biofilms were treated for up to 12 hours with 5% glucose. RESULTS: Ions interfered with the growth of S mutans by reducing its biomass (Ni(2+), Fe(3+), Cr(3+)), raising its rates of sugar metabolism (Ni(2+), Fe(3+), Cr(3+)), and raising its secretion of lactate (Ni(2+), Fe(3+), Cr(3+), pool). CONCLUSION: The laboratory data presented here point to the possibility of virulence increase of S mutans by metal ions commonly released during orthodontic therapy.

Differential adhesion of Streptococcus mutans to metallic brackets induced by saliva from caries-free and caries-active individuals.

AIM: The purpose of this study was to evaluate the influence of saliva obtained from caries-free and caries-active individuals on the adhesion rates of Streptococcus mutans to metallic brackets. METHODS: The unstimulated whole saliva of four caries-free (decayed, missing, or filled surfaces = 0) volunteers and four caries-active (decayed, missing, or filled surfaces >12) patients were collected. The saliva samples from each group were mixed and clarified. Acquired pellicles were formed onto 30 metallic edgewise brackets for premolars for each saliva group. The brackets were put in contact with planktonic cells of Streptococcus mutans ATCC 25175. Adhesion rates were assessed by crystal violet retention technique. RESULTS: A higher streptococcal adhesion pattern (P < 0.00001) was observed on acquired pellicles formed by saliva from caries-active donors. CONCLUSIONS: The results showed that saliva from caries-active patients tends to increase the mutans adhesion to surfaces, which is a point of concern for orthodontists.

Molecular fingerprinting methods for studies involving oral Candida albicans: [review] / Métodos de caracterização molecular para estudos envolvendo Candida albicans de origem bucal: [revisão]

OBJECTIVE: This review was aimed to discuss the literature concerning the fingerprint methods for epidemiological studies of oral-borne Candida albicans. DISCUSSION: Interest in obtaining a better understanding of the pathogenesis, epidemiology, genetics and evolution of Candida albicans has led to the development of innumerable investigations. These studies have employed fingerprinting systems, such as multilocus enzyme electrophoresis, electrophoretic karyotyping, randomly amplified polymorphic DNA, and restriction length fragment polymorphism, with and without hybridization. The efficacy of these systems has been examined at different levels of discrimination. A validation strategy has been delineated which compares two or more unrelated methods. Moreover, the different fingerprinting patterns produced could be registered in database programs and submitted to comparison with parameters of the host and characteristics of the pathogen. These procedures permit urrent and retrospective comparison of a selection of clinical and epidemiologically important strains, which could show one or several characteristics of the host or pathogen. Additionally, the sum of this growing amount of information could contribute even more to the understanding of the dynamics of infectious organisms in human populations, the complex relationship between commensalism and infection, and genetic and evolutionary mechanisms. CONCLUSIONS: Multiple molecular systems are available for studies involving C. albicans. This growing amount of information contributes to the understanding of the dynamics of this fungus in human populations.

OBJETIVO: Esta revisão discute as informações existentes acerca dos métodos de caracterização para estudos epidemiológicos envolvendo Candida albicans de origem bucal. DISCUSSÃO: O interesse no melhor entendimento da patogênese, epidemiologia, genética e evolução de C. albicans tem levado os pesquisadores à condução de inúmeras investigações. Esses estudos empregam sistemas de caracterização molecular como eletroforese de enzimas multilocus, cariotipagem por eletroforese, amplificação do DNA polimórfico ao acaso e polimorfismo dos fragmentos de restrição com e sem hidridização. A eficácia desses sistemas tem sido avaliada nos seus diferentes níveis de discriminação. Uma estratégia de validação foi delineada, a qual compara dois ou mais métodos não relacionados. Ainda, os diferentes padrões de caracterização molecular produzem dados que podem ser avaliados por programas computacionais e permite a comparação comparâmetros do hospedeiro e características do patógeno. Tais procedimentos permitem comparações correntes e retrospectivas de cepas clínicas e epidemiologicamente importantes, que podem mostrar uma ou mais características do hospedeiro ou do patógeno. A somatória do montante de informação pode contribuir para o entendimento da dinâmica dos organismos infecciosos em populações humanas, as relações complexas entre comensalismo e infecção, e mecanismos genéticos e evolutivos. CONCLUSÕES: Vários sistemas de caracterização molecular estão disponíveis para estudos envolvendo C. albicans. Este aumento de informação contribui na compreensão da dinâmica deste fungo em populações humanas.