Proteome difference among the salivary proteins adsorbed onto metallic orthodontic brackets and hydroxyapatite discs.

The aim of this study was to investigate the atomic composition and the proteome of the salivary proteins adsorbed on the surface of orthodontic metallic bracket. For this, the atomic composition of orthodontic metallic brackets was analyzed with X-ray Photoelectron Spectroscopy (XPS). The acquired bracket pellicle was characterized after brackets were immersed in human whole saliva supernatant for 2 hours at 37°C. Hydroxyapatite (HA) discs were used as a control. Acquired pellicle was harvested from the HA discs (n = 12) and from the metallic brackets (n = 12). Proteomics based on mass spectrometry technology was used for salivary protein identification and characterization. Results showed that most of the proteins adsorbed on the surface of orthodontic metallic brackets and on the HA discs were identified specifically to each group, indicating a small overlapping between the salivary proteins on each study group. A total of 311 proteins present on the HA discs were unique to this group while 253 proteins were unique to metallic brackets, and only 45 proteins were common to the two groups. Even though most proteins were unique to each study group, proteins related to antimicrobial activity, lubrication, and remineralization were present in both groups. These findings demonstrate that the salivary proteins adsorbed on the bracket surface are dependent on the material molecular composition.

Virulence properties and sensitivity profile of Candida parapsilosis complex species and Kodamaea ohmeri isolates from onychomycosis of HIV/AIDS patients.

Cutaneous fungal infections include onychomycosis, an infection of the nail that affects both healthy and immunocompromised patients. This study investigated the in vitro hydrolytic enzymes production, adhesion and biofilm formation capacity of Candida parapsilosis complex species and Kodamaea ohmeri isolates from onychomycoses of HIV/AIDS patients and also established the antifungal sensitivity profiles of these isolates. Onychomycosis in HIV/AIDS patients showed a high prevalence of emerging yeasts, among which C. parapsilosis complex species and K. ohmeri were the most frequent. Three C. parapsilosis sensu stricto and two C. orthopsilosis isolates were resistant to amphotericin B and 83% of isolates were resistant to terbinafine. All three different species evaluated were proteinase and hemolysin producers. All isolates adhered to stainless steel and siliconized latex surfaces, and carbohydrates intensified adhesion of all isolates. Isolates adhered to keratinous nail and 50% formed biofilms with strong intensity. In multispecies or polymicrobial biofilms, C. albicans and Staphylococcus aureus regulated the biofilm formation of the analyzed species, decreasing the number of their cells in biofilms. The isolation of emerging yeast species from onychomycosis which are great producers of hydrolytic enzymes and with high adhesion and biofilm formation capacity is a result that should be considered relevant in clinical practice. In addition, half of the isolates was resistant to at least one of the tested antifungals. Taken together these data corroborate the infectious capacity and viability of these isolates under favorable conditions.

Revealing the Amylase Interactome in Whole Saliva Using Proteomic Approaches.

Understanding proteins present in saliva and their function when isolated is not enough to describe their real role in the mouth. Due to protein-protein interactions, structural changes may occur in macromolecules leading to functional modulation or modification. Besides amylase's function in carbohydrate breakdown, amylase can delay proteolytic degradation of protein partners (e.g., histatin 1) when complexed. Due to its biochemical characteristics and high abundance in saliva, amylase probably interacts with several proteins acting as a biological carrier. This study focused on identifying interactions between amylase and other proteins found in whole saliva (WS) using proteomic approaches. Affinity chromatography was used, followed by gel electrophoresis methods, sodium dodecyl sulfate and native, tryptic in-solution and in-gel digestion, and mass spectrometry. We identified 66 proteins that interact with amylase in WS. Characterization of the identified proteins suggests that acidic (pI < 6.8) and low molecular weight (MW < 56 kDa) proteins have preference during amylase complex formation. Most of the identified proteins present biological functions related to host protection. A new protein-amylase network was constructed using the STRING database. Further studies are necessary to investigate individualities of the identified amylase interactors. These observations open avenues for more comprehensive studies on not yet fully characterized biological function of amylase.

Acquired Enamel Pellicle Engineered Peptides: Effects on Hydroxyapatite Crystal Growth.

The aim of this study was to test the hypothesis that duplication/hybridization of functional domains of naturally occurring pellicle peptides amplified the inhibitory effect of hydroxyapatite crystal growth, which is related to enamel remineralization and dental calculus formation. Histatin 3, statherin, their functional domains (RR14 and DR9), and engineered peptides (DR9-DR9 and DR9-RR14) were tested at seven different concentrations to evaluate the effect on hydroxyapatite crystal growth inhibition. A microplate colorimetric assay was used to quantify hydroxyapatite crystal growth. The half-maximal inhibitory concentration (IC50) was determined for each group. ANOVA and Student-Newman-Keuls pairwise comparisons were used to compare the groups. DR9-DR9 increased the inhibitory effect of hydroxyapatite crystal growth compared to single DR9 (p < 0.05), indicating that functional domain multiplication represented a strong protein evolution pathway. Interestingly, the hybrid peptide DR9-RR14 had an intermediate inhibitory effect compared to DR9 and DR9-DR9. This study used an engineered peptide approach to investigate a potential evolution protein pathway related to duplication/hybridization of acquired enamel pellicle's natural peptide constituents, contributing to the development of synthetic peptides for therapeutic use against dental caries and periodontal disease.

Merging in-silico and in vitro salivary protein complex partners using the STRING database: A tutorial.

Protein-protein interaction is a common physiological mechanism for protection and actions of proteins in an organism. The identification and characterization of protein-protein interactions in different organisms is necessary to better understand their physiology and to determine their efficacy. In a previous in vitro study using mass spectrometry, we identified 43 proteins that interact with histatin 1. Six previously documented interactors were confirmed and 37 novel partners were identified. In this tutorial, we aimed to demonstrate the usefulness of the STRING database for studying protein-protein interactions. We used an in-silico approach along with the STRING database (http://string-db.org/) and successfully performed a fast simulation of a novel constructed histatin 1 protein-protein network, including both the previously known and the predicted interactors, along with our newly identified interactors. Our study highlights the advantages and importance of applying bioinformatics tools to merge in-silico tactics with experimental in vitro findings for rapid advancement of our knowledge about protein-protein interactions. Our findings also indicate that bioinformatics tools such as the STRING protein network database can help predict potential interactions between proteins and thus serve as a guide for future steps in our exploration of the Human Interactome. SIGNIFICANCE: Our study highlights the usefulness of the STRING protein database for studying protein-protein interactions. The STRING database can collect and integrate data about known and predicted protein-protein associations from many organisms, including both direct (physical) and indirect (functional) interactions, in an easy-to-use interface.

Avaliação cefalométrica dos efeitos do aparelho herbst no tratamento da deficiência mandibular na dentadura permanente / Cephalometric evaluation of the effect of the herbst appliance in the treatment of the mandibular retrognathism in the permanent dentition

OBJETIVO: o objetivo do presente estudo cefalométrico retrospectivo consistiu em investigar os efeitos induzidos pelo aparelho Herbst, complementados pela mecânica ortodôntica com aparelho Straight wire e elásticos de Classe II, na correção da má oclusão Classe II, divisão 1, Padrão II, com deficiência mandibular, na dentadura permanente. METODOLOGIA: foram traçadas telerradiografias iniciais (idade média de 12 anos e 10 meses) e finais (idade média de 14 anos e 8 meses) de 18 pacientes, 12 meninos e 6 meninas, para quantificar o comportamento de 12 grandezas cefalométricas representativas da posição sagital das bases apicais, convexidade facial, rotação mandibular e posição sagital dos incisivos superiores e inferiores. O tempo médio de tratamento foi de 22,5 meses, sendo 9,8 meses com o aparelho Herbst e 13 meses com a mecânica ortodôntica subseqüente. RESULTADOS E CONCLUSÕES: os resultados registraram: 1) ausência de influência no comportamento da maxila; 2) avanço mandibular; 3) redução na convexidade facial; 4) preservação da inclinação do plano mandibular e 5) presença de compensação dentária, sobretudo nos incisivos inferiores (vestibularização). Reitera-se, portanto, o fato de que, mesmo com aparelho ortopédico fixo, é mais previsível e mais fácil obter compensação dentária do que remodelação esquelética na correção ortopédica da deficiência mandibular.

AIM: The purpose of the current cephalometric study was to investigate the effects induced by the Herbst appliance followed by fixed orthodontic Straight wire mechanics and Class I elastics to correct a Class II division 1 malocclusion with a mandibular deficiency in the permanent dentition. MATERIAL AND METHODS: Initial (mean age of 12 years and 10 months) and final (mean age of 14 years and 8 months) cephalometric radiographs of 12 boys and 6 girls were traced to measure 12 cephalometric measurements that represented the sagittal position of the apical bases, facial convexity, mandibular rotation and sagittal position of the upper and lower incisors. Mean treatment time was 22.5 months, with 9.8 months using the Herbst appliance and 13 months with the fixed orthodontic mechanics. RESULTS AND CONCLUSIONS: The results showed: 1) no influence in the maxilla; 2) mandibular advancement; 3) reduction on the facial convexity; 4) maintenance of the mandibular plane inclination; 5) dental compensation mainly in the lower incisors (buccal tipping). Therefore, even with the Herbst fixed appliance it is more predictable and easy to obtain dental compensation than skeletal remodelling in the orthopedic correction of the mandibular deficiency.