Ocellatin peptides from the skin secretion of the South American frog Leptodactylus labyrinthicus (Leptodactylidae): characterization, antimicrobial activities and membrane interactions

Abstract Background The availability of antimicrobial peptides from several different natural sources has opened an avenue for the discovery of new biologically active molecules. To the best of our knowledge, only two peptides isolated from the frog Leptodactylus labyrinthicus, namely pentadactylin and ocellatin-F1, have shown antimicrobial activities. Therefore, in order to explore the antimicrobial potential of this species, we have investigated the biological activities and membrane interactions of three peptides isolated from the anuran skin secretion. Methods Three peptide primary structures were determined by automated Edman degradation. These sequences were prepared by solid-phase synthesis and submitted to activity assays against gram-positive and gram-negative bacteria and against two fungal strains. The hemolytic properties of the peptides were also investigated in assays with rabbit blood erythrocytes. The conformational preferences of the peptides and their membrane interactions have been investigated by circular dichroism spectroscopy and liposome dye release assays. Results The amino acid compositions of three ocellatins were determined and the sequences exhibit 100% homology for the first 22 residues (ocellatin-LB1 sequence). Ocellatin-LB2 carries an extra Asn residue and ocellatin-F1 extra Asn-Lys-Leu residues at C-terminus. Ocellatin-F1 presents a stronger antibiotic potential and a broader spectrum of activities compared to the other peptides. The membrane interactions and pore formation capacities of the peptides correlate directly with their antimicrobial activities, i.e., ocellatin-F1 > ocellatin-LB1 > ocellatin-LB2. All peptides acquire high helical contents in membrane environments. However, ocellatin-F1 shows in average stronger helical propensities. Conclusions The obtained results indicate that the three extra amino acid residues at the ocellatin-F1 C-terminus play an important role in promoting stronger peptide-membrane interactions and antimicrobial properties. The extra Asn-23 residue present in ocellatin-LB2 sequence seems to decrease its antimicrobial potential and the strength of the peptide-membrane interactions.

Ocellatin peptides from the skin secretion of the South American frog Leptodactylus labyrinthicus (Leptodactylidae): characterization, antimicrobial activities and membrane interactions

Background The availability of antimicrobial peptides from several different natural sources has opened an avenue for the discovery of new biologically active molecules. To the best of our knowledge, only two peptides isolated from the frog Leptodactylus labyrinthicus, namely pentadactylin and ocellatin-F1, have shown antimicrobial activities. Therefore, in order to explore the antimicrobial potential of this species, we have investigated the biological activities and membrane interactions of three peptides isolated from the anuran skin secretion. Methods Three peptide primary structures were determined by automated Edman degradation. These sequences were prepared by solid-phase synthesis and submitted to activity assays against gram-positive and gram-negative bacteria and against two fungal strains. The hemolytic properties of the peptides were also investigated in assays with rabbit blood erythrocytes. The conformational preferences of the peptides and their membrane interactions have been investigated by circular dichroism spectroscopy and liposome dye release assays. Results The amino acid compositions of three ocellatins were determined and the sequences exhibit 100% homology for the first 22 residues (ocellatin-LB1 sequence). Ocellatin-LB2 carries an extra Asn residue and ocellatin-F1 extra Asn-Lys-Leu residues at C-terminus. Ocellatin-F1 presents a stronger antibiotic potential and a broader spectrum of activities compared to the other peptides. The membrane interactions and pore formation capacities of the peptides correlate directly with their antimicrobial activities, i.e., ocellatin-F1 > ocellatin-LB1 > ocellatin-LB2. All peptides acquire high helical contents in membrane environments. However, ocellatin-F1 shows in average stronger helical propensities. Conclusions The obtained results indicate that the three extra amino acid residues at the ocellatin-F1 C-terminus play an important role in promoting stronger peptide-membrane interactions and antimicrobial properties. The extra Asn-23 residue present in ocellatin-LB2 sequence seems to decrease its antimicrobial potential and the strength of the peptide-membrane interactions.(AU)

Evaluation of antimicrobial activity and cell viability of Aloe vera sponges

Background: Aloe vera L., member of the Liliaceae family, has been shown to stimulate cell proliferation and contribute to healing and angiogenesis, has anti-bacterial, anti-fungal and anti-inflammatory activity. In addition, Aloe vera can be used as a support for drug transport. Our objective is to evaluate antimicrobial activity and cytotoxicity of sponges of Aloe vera L. for use as a carrying support of drugs. Results: In this work, sponge of free Aloe vera (AV) loaded with amoxicillin (AMX) or nystatin (NYS) at 1% w/w, were prepared and physico-chemically characterized via X-ray diffraction, Fourier Transform Infrared Spectroscopy and thermal analysis. Antimicrobial potency of AV sponge alone, loaded with AMX or NYS, against strains of Streptococcus mutans, Staphylococcus aureus, Aggregatibacter actinomycetemcomitans, Enterococcus faecalis and Candida albicans was determined. Osteoblasts and human gingival fibroblasts were cultivated on AV, Aloe vera loaded with amoxicillin (AV/AMX) and Aloe vera loaded with nystatin (AV/NYS) and cellular viability was assessed. The physico-chemical characterization performed suggested that the loaded drugs were dispersed in the sponge and those interactions between the AV sponge and the loaded drugs were weak. Furthermore, AV loaded with AMX or NYS demonstrated antimicrobial potency and osteoblasts and fibroblasts were viable after 24 hrs on free AV, and AV loaded with AMX or NYS. Conclusions: Our results indicate that sponges of free AV, loaded with AMX or NYS, are biocompatible and exhibit antimicrobial activity.

Digestibilidade de nutrientes e balanço de Ca e P em suínos recebendo dietas com ácido butírico, fitase e diferentes níveis de cálcio / Nutrient digestibility and Ca and P balance in pigs receiving butyric acid, phytase and different calcium levels

Estudou-se o uso do ácido butírico (AB) e da fitase em dietas de suínos na fase de crescimento, variando no nível de cálcio. O experimento foi subdivido no tempo em dois períodos de 17 dias, sendo três de adaptação e 14 de mensurações. Em cada período, foram utilizados 16 suínos machos castrados, com peso de 24,6±0,7kg no primeiro e 43,2±1,77kg no segundo período. As dietas diferiam no nível de cálcio (0,5 ou 0,72 por cento), de AB (0 ou 0,3 por cento de butirato de sódio 84 por cento) e de fitase (0 ou 500 FTU kg-1, fitase de origem bacteriana derivada de Escherichia coli). O delineamento foi em blocos casualizados (períodos), em decomposição fatorial 2x2x2, com quatro repetições. Foram avaliadas a digestibilidade aparente dos nutrientes e da energia bruta e o balanço de Ca e P. O AB melhorou a digestibilidade da proteína bruta, mas, de forma individual ou em combinação com a fitase, não aumentou a retenção de minerais. A fitase aumentou a retenção de P, reduzindo sua excreção fecal e urinária. O menor nível de Ca na dieta proporcionou maior retenção de Ca e menor retenção de P, em decorrência do aumento da excreção de P na urina (P<0,0001). Apesar de ter melhorado a digestibilidade protéica, o AB não aumentou a retenção de minerais, nem teve efeito aditivo ao uso de fitase, enquanto que a fitase apresentou efeito positivo para retenção de P.

It was studied the use of butyric acid (BA) and phytase in growing pigs diets, varying calcium level. The experiment was divided into two periods of time, of 17 days, with 3 days of adaptation and 14 of measurements. In each period, it was used 16 barrows weighing 24.6±0.7kg in the first and 43.2±1.77kg in the second. Diets were different in calcium level (0.5 or 0.72 percent), AB (0 or 0.3 percent sodium butyrate 84 percent) and phytase (0 or 500FTU kg-1 phytase of bacterial origin derived from Escherichia coli). The experimental design was in randomized blocks (periods), decomposed in 2x2x2 factorial, with four replications. It was evaluated the apparent digestibility of nutrients, gross energy and balance of Ca and P. AB improved crude protein digestibility, but individually or in combination with phytase did not increase minerals retention. Phytase increased P retention by reducing urinary and fecal excretion. The lowest diet calcium level provided higher Ca retention and lower P retention as a result of increased P excretion in urine (P<0.0001). Despite improving protein digestibility, AB did not increase mineral retention and didn't have an additive effect with the use of phytase, while phytase had positive effect on retention of P.

Bioceramic/Poly (glycolic)-poly (lactic acid) composite induces mineralized barrier after direct capping of rat tooth pulp tissue

The aim of this study was to observe the histopathological pulp response following direct pulp capping of mechanically exposed teeth in rats with a composite of beta-tricalcium phosphate-hydroxyapatite bioceramic (BC) and poly (glycolic)-poly (lactic acid) (PLGA) material or a calcium hydroxide [Ca(OH)2] material, compared to BC alone and a negative control of water. Pulp of the maxillary molars was exposed, followed by capping with the experimental material. The pulpal tissue response was assessed post-operatively at 1, 7, 14 and 30 d, followed by histological analysis. The Ca(OH)2 group exhibited severe acute inflammatory cell infiltration at day 14. However after 30 d, a new hard tissue with macro porous obliteration of the pulp chamber and a characteristic necrotic area had appeared. BC and Ca(OH)2 capping were associated with moderate inflammation and dentinal bridge similar. Meanwhile, in the BC/PLGA composite group, there was moderate inflammatory infiltrate and formation of a dense and complete dentinal bridge. In conclusion, the BC/PLGA composite material showed a large zone of tertiary dentin, and effectively reorganized the dentin-pulp complex.

Clinical evaluation of packable resin Class I restorations after 7 years

Aims: Compactable composite resins have been indicated as amalgam substitutes. However, longitudinal clinical trials are necessary to verify their wear resistance and integrity maintenance. The purpose of this study was to evaluate the clinical performance of a packable resin in Class I restorations after 7 years. Methods: Forty restorations were placed in 15 young patients aged 13 to 30 years. The restorative material (Prodigy/OptiBond-KERR®) was used according to standard recommendations. The restorations were assessed at baseline at the year 2000 and after 2 and 7 years according to the USPHS (United State Public Health Service) criteria. Results: After 7 years, 50% of the restorations were scored Alpha and 37.5% scored Bravo for color match, marginal discoloration and marginal adaptation. Secondary caries were observed in only one restoration and none of them presented postoperative sensibility. Conclusion: In accordance with the USPHS method used, the packable resin presented appropriate clinical performance after a 7-year clinical evaluation.

Antimicrobial activity of a propolis adhesive formulation on different oral pathogens

Recent studies have shown that propolis has appreciable antibacterial, antifungal and antiviral actions, as well as cytostatic and antitumoral activity. In light of these studies, the antimicrobial activity of a new adhesive formulation containing propolis was evaluated in this in vitro study. Susceptibility of the oral strains tested (Candida albicans, Candida tropicalis, Streptococcus mutans, Staphylococcus aureus, Enterococcus faecalis, Actinomyces israelli, Actinobacillus actinomycetemcomitans) was evaluated using the agar diffusion method with different concentrations of propolis (5, 10, 15 and 20%). All of the assayed bacteria and fungi species were susceptible to propolis, with minimum inhibitory concentrations (MIC) ranging from 1.75 to 14.0 ãfg/ml. The positive results suggest that propolis in this sustained release formulation should be further tested as an alternative therapy of infectious conditions of the oral cavity, such as denture stomatitis and periodontitis. However, in vivo studies of the effect of this new adhesive formulation of propolis are needed to determine its possible effects on the oral mucosa.

Estado actual de la indicación de antimicrobianos para la medicación intracanal / Current state of antimicrobial indications for intracanal medication

La irrigación del sistema de canales radiculares durante el tratamiento endodóntico, así como la medicacion intracanal eficiente y no tóxica a los tejidos periapicales es indispensable complemento en la cura y eliminación de tejidos necróticos de los canales. El objetivo de este trabajo fue analizar los efectos de los principales antimicrobianos utilizados en la desinfección del sistema de canales radiculares, abordando sus ventajas, desventajas y especialmente incorporar los nuevos conocimientos en las áreas de microbiología y de uso tópico de amplia utilización en odontología, tales como hipoclorito de sodio, clorhexidina, con uso más reciente, EDTA, hidróxido de calcio y paramonoclorofenol. La literatura muestra que, a pesar de su largo uso en endodoncia, inumerables desventajas son señaladas en relación al hipoclorito de sodio. El uso de EDTA está indicado solamente antes de la obturación del canal, debido a su fuerte acción quelante, y la clorhexidina en gel es una buena alterantiva cuando se considera su actividad antimicrobiana, detergente y biológica. La medicación intracanal debe ser entendida llevando en cuenta la fuerte relación entre bacterias y hongos, formando biofilms y de esa forma, los agentes usados necesitan tener un amplio rango de acción, capacidad de limpieza, prevenir la extrusión de debris en los tejidos periapicales y especialmente con baja toxicidad. Podemos concluir que ningún antimicrobiano cumple con todas las exigencias y el uso debe ser analizado siguiendo el criterio clínico, especialmente en relación a la sintomatología. El hidróxido de calcio permanece como primera opción en dientes asintomáticos y sin infección periapical; la clorhexidina en gel estaría más indicada en dientes con lesiones crónicas o persistentes

Emprego de forças magnéticas em ortodontia e ortopedia facial. Uma revisão / Employment of magnetic forces in orthodontic and facial orthopedics. A review

Este artigo tem por objetivo revisar a literatura sobre a utilização de forças magnéticas em Ortodontia e Ortopedia Facial. Fez-se uma descrição da aparatologia mecânica assim como da dinâmica empregada pelos aparelhos magnetizados e seus resultados. O emprego dos magnetos associados aos métodos convencionais mostrou-se eficaz em várias indicações clínicas, distalizações dentárias, apnéia do sono, forças intermaxilares para correção de Classe II e III, mordidas abertas, impactações dentárias

Evaluation of the substantivity of chlorhexidine in association with sodium fluoride in vitro

A efetividade da associaçäo fluoreto-clorexidina na prevençäo da gengivite e da cárie vem sendo defendida desde alguns anos 5,7,14. O propósito dessa associaçäo é ter um desempenho sinergistico da mesma. O objetivo do presente estudo foi avaliar a substantividade da clorexidina em associaçäo ou näo ao fluoreto de sódio em diferentes intervalos de tempo, in vitro. Foram tratadas superfícies de esmalte bovino com soluções de digluconato de clorexidina 0,12 por cento, Periogardâ - Colgateâ ou fluoreto de sódio 0,5 por cento-clorexidina 0,12 por cento Duplakâ -Dentsplyâ durante um minuto. A substantividade foi medida pela dessorçäo da clorexidina a partir dos fragmentos previamente imersos nas soluções teste e colocados em água destilada. Alíquotas foram removidas em intervalos de 5`, 30` e 6 horas e analisadas através da espectroscopia na regiäo do ultravioleta visível. Os valores obtidos foram analisados estatisticamente pelo teste de T-student. Os resultados mostraram que a concentraçäo da clorexidina foi significativamente reduzida quando em associaçäo com fluoreto de sódio (p <0.05). Os resultados in vitro sugerem que a associaçäo da clorexidina com fluoreto de sódio nas concentrações estudadas parece näo ter efeito benéfico devido à reduçäo da substantividade da clorexidina