Genomic insights into organic acid production and plant growth promotion by different species of phosphate-solubilizing bacteria.

Bacteria can solubilize phosphorus (P) through the secretion of low-molecular-weight organic acids and acidification. However, the genes involved in the production of these organic acids are poorly understood. The objectives of this study were to verify the calcium phosphate solubilization and the production of low-molecular-weight organic acids by diverse genera of phosphate solubilizing bacterial strains (PSBS); to identify the genes related to the synthesis of the organic acids in the genomes of these strains and; to evaluate growth and nutrient accumulation of maize plants inoculated with PSBS and fertilized with Bayóvar rock phosphate. Genomic DNA was extracted for strain identification and annotation of genes related to the organic acids production. A greenhouse experiment was performed with five strains plus 150 mg dm- 3 P2O5 as Bayóvar rock phosphate (BRP) to assess phosphate solubilization contribution to maize growth and nutrition. Paraburkholderia fungorum UFLA 04-21 and Pseudomonas anuradhapurensis UFPI B5-8A solubilized over 60% of Ca phosphate and produced high amounts of citric/maleic and gluconic acids in vitro, respectively. Eleven organic acids were identified in total, although not all strains produced all acids. Besides, enzymes related to the organic acids production were found in all bacterial genomes. Plants inoculated with strains UFPI B5-6 (Enterobacter bugandensis), UFPI B5-8A, and UFLA 03-10 (Paenibacillus peoriae) accumulated more biomass than the plants fertilized with BRP only. Strains UFLA 03-10 and UFPI B5-8A increased the accumulation of most macronutrients, including P. Collectively, the results show that PSBS can increase maize growth and nutrient accumulation based on Bayóvar rock phosphate fertilization.

Evaluation of the operational conditions of the glucose oxidase and catalase multienzymatic system through enzyme co-immobilization on amino hierarchical porous silica.

Hexaric acids have attracted attention lately because they are platform chemicals for synthesizing pharmaceuticals. In particular, gluconic acid is one of the most studied because it is readily available in nature. In this work, operational conditions like temperature and pH were evaluated for the enzymatic production of gluconic acid. For this purpose, glucose oxidase (GOx) and catalase (CAT) were individually immobilized and co-immobilized using amino-silica as support. The catalytic performance of the enzymes both as separate biocatalysts (GOx or CAT) and as an enzymatic complex (GOx-CAT) was assessed in terms of enzymatic activity and stability at temperatures 45 °C and 50 °C and pH 6 to 8. The results show that CAT is a key enzyme for gluconic acid production as it prevents GOx from being inhibited by H2O2. However, CAT was found to be less stable than GOx. Therefore, different GOx to CAT enzymatic ratios were studied, and a ratio of 1-3 was determined to be the best. The highest glucose conversion conditions were 45 °C and pH 7.0 for 24 h. Regarding the biocatalyst reuse, GOx-CAT retained more than 70% of its activity after 6 reaction cycles. These results contribute to further knowledge and application of oxidases for hexaric acid production and shed greater light on the role of the glucose oxidase/catalase pair in better catalytic performance. Both enzymes were immobilized in one pot, which is relevant for their potential use in industry; an enzyme system was obtained in a single step.

Comparative study of the effectiveness and residual effect of preoperative antisepsis with 4% chlorhexidine gluconate associated with 70% ethyl alcohol and 0.5% alcoholic chlorhexidine gluconate in dogs / Estudo comparativo da eficácia e do efeito residual da antissepsia pré-operatória com gluconato de clorexidina 4% associado a álcool etílico 70% e gluconato de clorexidina alcoólico 0.5% em cães

The effectiveness of antisepsis of surgical sites in 20 animals (canine species) was compared and subdivided into two groups, using 4% chlorhexidine gluconate associated with alcohol (group 1) and 0.5% chlorhexidine gluconate (group 2). The samples were collected through skin swab after trichotomy (T1), after definitive antisepsis (T2) and one hour after the use of antiseptic (T3), and then submitted to the count of colony forming units (CFU). In both groups, bacterial growth occurred in T1; in T2, the reduction of CFUs was significant for both groups (G1 and G2); however, if we consider absolute values, we can see in T1 a greater amount of CFUs in G2, and when evaluating the results of T2, we can see values which are very similar between G1 and G2, which may suggest greater efficiency of G2 in initial times after antisepsis. In T3, the reduction of CFUs was more effective for G1, suggesting a greater residual effect when compared to G2. Both antiseptic protocols were effective as they significantly reduced the number of skin bacteria, both in T2 and T3.

A eficácia da antissepsia dos sítios cirúrgicos em 20 animais (espécie canina) foi comparada e subdividida em dois grupos, utilizando gluconato de clorexidina 4% associado ao álcool (grupo 1) e gluconato de clorexidina 0,5% (grupo 2). As amostras foram coletadas por meio de swab cutâneo após tricotomia (T1), após antissepsia definitiva (T2) e uma hora após o uso de antisséptico (T3), sendo então submetidas à contagem das unidades formadoras de colônias (UFC). Em ambos os grupos, o crescimento bacteriano ocorreu em T1; em T2, a redução das UFCs foi significativa para ambos os grupos (G1 e G2); porém, se considerarmos os valores absolutos, podemos observar em T1 uma maior quantidade de UFCs no G2, e ao avaliar os resultados de T2, podemos observar valores que são muito semelhantes entre G1 e G2, o que pode sugerir maior efi-ciência de G2 em tempos iniciais após a antissepsia. No T3, a redução das UFCs foi mais efetiva para o G1, sugerindo maior efeito residual quando comparado ao G2. Ambos os protocolos antissépticos foram eficazes, pois reduziram significativamente o número de bactérias cutâneas, tanto em T2 quanto em T3.

Comparative study of the effectiveness and residual effect of preoperative antisepsis with 4% chlorhexidine gluconate associated with 70% ethyl alcohol and 0.5% alcoholic chlorhexidine gluconate in dogs / Estudo comparativo da eficácia e do efeito residual da antissepsia pré-operatória com gluconato de clorexidina 4% associado a álcool etílico 70% e gluconato de clorexidina alcoólico 0.5% em cães

The effectiveness of antisepsis of surgical sites in 20 animals (canine species) was compared and subdivided into two groups, using 4% chlorhexidine gluconate associated with alcohol (group 1) and 0.5% chlorhexidine gluconate (group 2). The samples were collected through skin swab after trichotomy (T1), after definitive antisepsis (T2) and one hour after the use of antiseptic (T3), and then submitted to the count of colony forming units (CFU). In both groups, bacterial growth occurred in T1; in T2, the reduction of CFUs was significant for both groups (G1 and G2); however, if we consider absolute values, we can see in T1 a greater amount of CFUs in G2, and when evaluating the results of T2, we can see values which are very similar between G1 and G2, which may suggest greater efficiency of G2 in initial times after antisepsis. In T3, the reduction of CFUs was more effective for G1, suggesting a greater residual effect when compared to G2. Both antiseptic protocols were effective as they significantly reduced the number of skin bacteria, both in T2 and T3.(AU)

A eficácia da antissepsia dos sítios cirúrgicos em 20 animais (espécie canina) foi comparada e subdividida em dois grupos, utilizando gluconato de clorexidina 4% associado ao álcool (grupo 1) e gluconato de clorexidina 0,5% (grupo 2). As amostras foram coletadas por meio de swab cutâneo após tricotomia (T1), após antissepsia definitiva (T2) e uma hora após o uso de antisséptico (T3), sendo então submetidas à contagem das unidades formadoras de colônias (UFC). Em ambos os grupos, o crescimento bacteriano ocorreu em T1; em T2, a redução das UFCs foi significativa para ambos os grupos (G1 e G2); porém, se considerarmos os valores absolutos, podemos observar em T1 uma maior quantidade de UFCs no G2, e ao avaliar os resultados de T2, podemos observar valores que são muito semelhantes entre G1 e G2, o que pode sugerir maior efi-ciência de G2 em tempos iniciais após a antissepsia. No T3, a redução das UFCs foi mais efetiva para o G1, sugerindo maior efeito residual quando comparado ao G2. Ambos os protocolos antissépticos foram eficazes, pois reduziram significativamente o número de bactérias cutâneas, tanto em T2 quanto em T3.(AU)

Cloning, purification, and characterization of the 6-phosphogluconate dehydrogenase (6 PGDH) from Giardia lamblia.

Giardia lamblia, due to the habitat in which it develops, requires a continuous supply of intermediate compounds that allow it to survive in the host. The pentose phosphate pathway (PPP) provides essential molecules such as NADPH and ribulose-5-phosphate during the oxidative phase of the pathway. One of the key enzymes during this stage is 6-phosphogluconate dehydrogenase (6 PGDH) for generating NADPH. Given the relevance of the enzyme, in the present work, the 6pgdh gene from G. lamblia was amplified and cloned to produce the recombinant protein (Gl-6 PGDH) and characterize it functionally and structurally after the purification of Gl-6 PGDH by affinity chromatography. The results of the characterization showed that the protein has a molecular mass of 54 kDa, with an optimal pH of 7.0 and a temperature of 36-42 °C. The kinetic parameters of Gl-6 PGDH were Km = 49.2 and 139.9 µM (for NADP+ and 6-PG, respectively), Vmax =26.27 µmol*min-1*mg-1, and Kcat = 24.0 s-1. Finally, computational modeling studies were performed to obtain a structural visualization of the Gl-6 PGDH protein. The generation of the model and the characterization assays will allow us to expand our knowledge for future studies of the function of the protein in the metabolism of the parasite.

Copper biodistribution after acute systemic administration of copper gluconate to rats.

Neurodegenerative disorders have been linked to the decrease of copper concentrations in different regions of the brain. Therefore, intake of micronutrient supplements could be a therapeutic alternative. Since the copper distribution profile has not been elucidated yet, the aim of this study was to characterize and to analyze the concentration profile of a single administration of copper gluconate to rats by two routes of administration. Male Wistar rats were divided into three groups. The control group received vehicle (n = 5), and the experimental groups received 79.5 mg/kg of copper orally (n = 4-6) or 0.64 mg/kg of copper intravenously. (n = 3-4). Blood, striatum, midbrain and liver samples were collected at different times. Copper concentrations were assessed using atomic absorption spectrophotometry. Copper concentration in samples from the control group were considered as baseline. The highest copper concentration in plasma was observed at 1.5 h after oral administration, while copper was quickly compartmentalized within the first hour after intravenous administration. The striatum evidenced a maximum metal concentration at 0.25 h for both routes of administration, however, the midbrain did not show any change. The highest concentration of the metal was held by the liver. The use of copper salts as replacement therapy should consider its rapid and discrete accumulation into the brain and the rapid and massive distribution of the metal into the liver for both oral and intravenous routes. Development of controlled-release pharmaceutical formulations may overcome the problems that the liver accumulation may imply, particularly, for hepatic copper toxicity.

Anticancer and antileishmanial in vitro activity of gold(I) complexes with 1,3,4-oxadiazole-2(3H)-thione ligands derived from δ-D-gluconolactone.

Four gold(I) complexes conceived as anticancer agents were synthesized by reacting [Au(PEt3 )Cl] and [Au(PPh3 )Cl] with ligands derived from δ-d-gluconolactone. The ligands' structure was designed to combine desired biological properties previously reported for each group. Ligands were synthesized from δ-d-gluconolactone via ketal protection and hydrazide formation followed by cyclization with CS2 to produce the novel oxadiazolidine-2-thione 7 and 8. Increasing of the ligands' lipophilicity via ketal protection proved useful since all four gold(I) complexes showed anticancer and antileishmanial properties. The IC50 values are at low micromolar range, varying from 2 to 3 µm for the most active compounds. The free D-gluconate 1,3,4 oxadiazole-derived ligands were neither toxic nor presented anticancer or antileishmanial properties. Triethylphosphine-derived compounds 9 and 10 were more selective against B16-F10 melanoma cell line. Although similar in vitro antileishmanial activity was observed for the gold(I) precursors themselves and their derived complexes, the latter were three times less toxic for human THP-1 macrophage cell line; this result is attributed to an isomeric variation of the D-gluconate ligand and the oxadiazole portion, which was one of the key concepts behind this work. These findings should encourage further research on gold(I) complexes to develop novel compounds with potential application in cancer and leishmaniasis chemotherapy.

The structure of a novel membrane-associated 6-phosphogluconate dehydrogenase from Gluconacetobacter diazotrophicus (Gd6PGD) reveals a subfamily of short-chain 6PGDs.

The enzyme 6-phosphogluconate dehydrogenase catalyzes the conversion of 6-phosphogluconate to ribulose-5-phosphate. It represents an important reaction in the oxidative pentose phosphate pathway, producing a ribose precursor essential for nucleotide and nucleic acid synthesis. We succeeded, for the first time, to determine the three-dimensional structure of this enzyme from an acetic acid bacterium, Gluconacetobacter diazotrophicus (Gd6PGD). Active Gd6PGD, a homodimer (70 kDa), was present in both the soluble and the membrane fractions of the nitrogen-fixing microorganism. The Gd6PGD belongs to the newly described subfamily of short-chain (333 AA) 6PGDs, compared to the long-chain subfamily (480 AA; e.g., Ovis aries, Homo sapiens). The shorter amino acid sequence in Gd6PGD induces the exposition of hydrophobic residues in the C-terminal domain. This distinct structural feature is key for the protein to associate with the membrane. Furthermore, in terms of function, the short-chain 6PGD seems to prefer NAD+ over NADP+ , delivering NADH to the membrane-bound NADH dehydrogenase of the microorganisms required by the terminal oxidases to reduce dioxygen to water for energy conservation. ENZYME: ECnonbreakingspace1.1.1.343. DATABASE: Structural data are available in PDB database under the accession number 6VPB.

Slow lactate gluconate exchange in calcium complexes during precipitation from supersaturated aqueous solutions.

Saturated solutions of calcium l-lactate in water or in deuterium oxide continuously dissolve calcium l-lactate by addition of solid sodium d-gluconate and become strongly supersaturated in calcium d-gluconate due to no or slow precipitation. The quantification of total dissolved calcium allied with the calcium complexes equilibrium constants allowed an ion speciation, which shows an initial non-thermal and spontaneous supersaturation of more than a factor of 50 at 25 °C only slowly decreasing after initiation of precipitation of calcium d-gluconate after a lag phase of several hours. A mathematical model is proposed, based on numerical solution of coupled differential equations of dynamics of l-lactate and d-gluconate exchange during the lag phase for precipitation and during precipitation. A slow exchange of l-lactate coordinated to calcium with d-gluconate is indicated with a time constant of 0.20 h-1 in water and of 0.15 h-1 in deuterium oxide and a kinetic deuterium/hydrogen isotope effect of 1.25. Such spontaneous non-thermal supersaturation and slow ligand exchange with a pseudo first order equilibration process with a half-life of 3.5 h in water for calcium hydroxycarboxylates can help to understand the higher calcium bioavailability from calcium hydroxycarboxylates compared to simple salts.

Effect of the lactose source on the ultrasound-assisted enzymatic production of galactooligosaccharides and gluconic acid.

It is well known that one of the main problems in galactooligosaccharide production (GOS) via tranglycosylation of lactose is the presence of monosaccharides that contribute to increasing the glycaemic index, as is the case of glucose. In this work, as well as studying the effect of ultrasound (US) on glucose oxidase (Gox) activation during gluconic acid (GA) production, we have carried out an investigation into the selective oxidation of glucose to gluconic acid in multienzymatic reactions (ß-galactosidase (ß-gal) and Gox) assisted by power US using different sources of lactose as substrate (lactose solution, whey permeate, cheese whey). In terms of the influence of matrix on GOS and GA production, lactose solution gave the best results, followed by cheese whey and whey permeate, salt composition being the most influential factor. The highest yields of GOS production with the lowest glucose concentration and highest GA production were obtained with lactose solution in multienzymatic systems in the presence of ultrasound (30% amplitude) when Gox was added after 1 h of treatment with ß-gal. This work demonstrates the ability of US to enhance efficiently the obtainment of prebiotic mixtures of low glycaemic index.

Zinc gluconate supplementation impacts the clinical improvement in patients with ulcerative colitis.

Ulcerative colitis is an inflammatory bowel disease that affects the mucous membrane of the colon. The pathogenesis is not clear, but there is evidence of a complex interaction between genetic, environmental, and immunological factors. In this regard, we highlight the role of zinc in the immune system and probable control of the disease. This study evaluated the effect of zinc supplementation on the inflammatory response in patients with ulcerative colitis. A blind interventional study involving 41 patients of both sexes, who underwent either zinc gluconate supplementation (n = 23), or treatment with a placebo (corn starch) (n = 18). Patients were evaluated for dietary zinc intake, plasma and erythrocyte zinc concentrations, and serum levels of Th1/Th2/Th17 type cytokines at baseline (T0) and 30 (T1) and 60 (T2) days after intervention. Patients in the zinc supplementation group had a lower probability of having an adequate zinc intake than placebo. In this same group, there was a significant difference between plasma zinc concentrations (T1 in relation to T0, T2 in relation to T1, and T2 in relation to T0) and erythrocyte zinc (T1 in relation to T0 and T2 in relation to T1). Zinc supplementation resulted in significant changes in the concentrations of IL-2 and IL-10 without differences in the other interleukins. Zinc gluconate intervention in patients with ulcerative colitis improves the nutritional status of this mineral in these patients and positively influences their clinical outcome, reinforcing the role of zinc as an important dietary component in disease control.

Insulin Delivery from Glucose-Responsive, Self-Assembled, Polyamine Nanoparticles: Smart "Sense-and-Treat" Nanocarriers Made Easy.

Polyamine-salt aggregates (PSA) are biomimetic soft materials that have attracted great attention due to their straightforward fabrication methods, high drug-loading efficiencies, and attractive properties for pH-triggered release. Herein, a simple and fast multicomponent self-assembly process was used to construct cross-linked poly(allylamine hydrochloride)/phosphate PSAs (hydrodynamic diameter of 360 nm) containing glucose oxidase enzyme, as a glucose-responsive element, and human recombinant insulin, as a therapeutic agent for the treatment of diabetes mellitus (GI-PSA). The addition of increasing glucose concentrations promotes the release of insulin due to the disassembly of the GI-PSAs triggered by the catalytic in situ formation of gluconic acid. Under normoglycemia, the GI-PSA integrity remained intact for at least 24 h, whereas hyperglycemic conditions resulted in 100 % cargo release after 4 h of glucose addition. This entirely supramolecular strategy presents great potential for the construction of smart glucose-responsive delivery nanocarriers.

The Novel N,N-bis-2-Hydroxyethyl-2-Aminoethanesulfonic Acid-Gluconate-Polyethylene Glycol-Hypothermic Machine Perfusion Solution Improves Static Cold Storage and Reduces Ischemia/Reperfusion Injury in Rat Liver Transplant.

Organ transplantation is the treatment of choice against terminal and irreversible organ failure. Optimal preservation of the graft is crucial to counteract cold ischemia effects. As we developed an N,N-bis-2-hydroxyethyl-2-aminoethanesulfonic acid-gluconate-polyethylene glycol (BGP)-based solution (hypothermic machine perfusion [HMP]), we aimed to analyze the use of this solution on static cold storage (SCS) of rat livers for transplantation as compared with the histidine tryptophan ketoglutarate (HTK) preservation solution. Livers procured from adult male Sprague Dawley rats were preserved with BGP-HMP or HTK solutions. Liver total water content and metabolites were measured during the SCS at 0°C for 24 hours. The function and viability of the preserved rat livers were first assessed ex vivo after rewarming (90 minutes at 37°C) and in vivo using the experimental model of reduced-size heterotopic liver transplantation. After SCS, the water and glycogen content in both groups remained unchanged as well as the tissue glutathione concentration. In the ex vivo studies, livers preserved with the BGP-HMP solution were hemodynamically more efficient and the O2 consumption rate was higher than in livers from the HTK group. Bile production and glycogen content after 90 minutes of normothermic reperfusion was diminished in both groups compared with the control group. Cellular integrity of the BGP-HMP group was better, and the histological damage was reversible. In the in vivo model, HTK-preserved livers showed a greater degree of histological injury and higher apoptosis compared with the BGP-HMP group. In conclusion, our results suggest a better role of the BGP-HMP solution compared with HTK in preventing ischemia/reperfusion injury in the rat liver model.

Design of enzymatic cascade processes for the production of low-priced chemicals.

While the application of enzymes to synthetic and industrial problems continues to grow, the major development today is focused on multi-enzymatic cascades. Such systems are particularly attractive, because many commercially available enzymes operate under relatively similar operating conditions. This opens the possibility of one-pot operation with multiple enzymes in a single reactor. In this paper the concept of modules is introduced whereby groups of enzymes are combined in modules, each operating in a single reactor, but with the option of various operating strategies to avoid any complications of nonproductive interactions between the enzymes, substrates or products in a given reactor. In this paper the selection of modules is illustrated using the synthesis of the bulk chemical, gluconic acid, from lignocellulosic waste.

Impact of ultrasound on galactooligosaccharides and gluconic acid production throughout a multienzymatic system.

Galactooligosaccharides (GOS), recognised prebiotic, can be industrially produced from lactose and commercial ß-galactosidase (ß-gal) from Kluyveromyces lactis. Residual lactose and glucose limit GOS applications. To handle this problem, a multienzymatic system, with ß-gal and glucose oxidase (Gox), was proposed to reduce glucose content in reaction media through its oxidation to gluconic acid (GA). Besides, ultrasound (US) probe effect over the multienzymatic system to produce GOS and GA has been evaluated. A production around 40% of GOS was found in all treatments after the first hour of reaction. However, glucose consumption and GA production was significantly higher (P < 0.05) for sequential reaction assisted by US, obtaining the best production of GOS (49%) and GA (28%) after 2 h of reaction. The conformational and residual activity changes of enzymes under US conditions were also evaluated, Gox being positively affected whereas in ß-gal hardly any change was found.

Atividade in vitro do extrato etanólico de própolis e do digluconato de clorexidina sobre as espécies de Candida isoladas da mucosa bucal de pacientes internados em Unidade de Terapia Intensiva (UTI) / In vitro activity of ethanolic extract of propolis and chlorhexidine digluconate on Candida species isolated from the oral mucosa of patients hospitalized in the Intensive Care Unit (ICU)

Avaliou-se a atividade dos extratos de própolis e digluconato de clorexidina em Candida sp isoladas da mucosa bucal de pacientes em UTI. Foram determinadas as concentrações fungicidas mínimas (CFM) e comparadas, nas doses sub-inibitórias, à produção de exoenzimas proteinase e fosfolipase e formação de franjas. Em 72 isolados foram avaliadas a atividade antifúngica pela técnica de microdiluição em série, na “base 2”, a produção das exoenzimas proteinase e fosfolipase, e a formação de franjas, antes e após a exposição às própolis e clorexidina. Dos 72 isolados, 53 eram C. albicans, 11 C. tropicalis, quatro C. guilhermondii e quatro sugestivas de C. dubliniensis. CFM 90% do extrato de própolis foi de 5% para C. albicans, 20% C. tropicalis, 0,625% C. guilhermondii e 0,312% sugestivas de C. dubliniensis. CFM 90% da clorexidina foi de 0,0018% para C. albicans, 0,012% C. tropicalis, de 0,0018% C. guilhermondii e de 0,00375% sugestivas de C. dubliniensis. Ocorreu inibição das exoenzimas e franjas, em ambos os produtos. Apesar da inibição da clorexidina ser menor que a da própolis, seu uso diário não causa efeitos colaterais indesejáveis como manchas nos dentes e na língua, perda do paladar e sensação de queimação na mucosa bucal.(AU)

The activity of propolis extract and chlorhexidine digluconate on Candida sp isolated from oral mucosa of patients in ICU was evaluated. The minimum fungicidal concentrations (MFC) were determined, and also the production of proteinase and phospholipase exoenzymes and the fringe formation. Seventy-two isolates were used and identified by the API 20C AUX® System. The antifungal activity was evaluated by “at base 2” serial microdilution technique. Also the exoenzymes production (proteinase and phospholipase), the fringes formation, before and after being exposed to propolis and chlorhexidine, were analysed. Of 72 isolates, 53 were C. albicans, 11 C. tropicalis, four C. guilhermondii and four suggestive C. dubliniensis. The MFC 90% of propolis extract was 5% C. albicans, 20% C. tropicalis, 0.625% C. guilhermondii; and 0.312% suggestive of C. dubliniensis. MFC 90% of chlorhexidine was 0.0018% C. albicans, 0.012% C. tropicalis, 0.0018% C. guilhermondii and 0.00375% suggestive of C. dubliniensis. The inhibition of exoenzymes and fringes occurred in the both products. Although the inhibition of chlorhexidine is lower than that showed by propolis, its daily use neither cause undesirable side effects as blemishes on the teeth and tongue, nor the loss of the taste and the burning sensation in the oral mucosa.(AU)

Atividade in vitro do extrato etanólico de própolis e do digluconato de clorexidina sobre as espécies de Candida isoladas da mucosa bucal de pacientes internados em Unidade de Terapia Intensiva (UTI) / In vitro activity of ethanolic extract of propolis and chlorhexidine digluconate on Candida species isolated from the oral mucosa of patients hospitalized in the Intensive Care Unit (ICU)

Avaliou-se a atividade dos extratos de própolis e digluconato de clorexidina em Candida sp isoladas da mucosa bucal de pacientes em UTI. Foram determinadas as concentrações fungicidas mínimas (CFM) e comparadas, nas doses sub-inibitórias, à produção de exoenzimas proteinase e fosfolipase e formação de franjas. Em 72 isolados foram avaliadas a atividade antifúngica pela técnica de microdiluição em série, na “base 2”, a produção das exoenzimas proteinase e fosfolipase, e a formação de franjas, antes e após a exposição às própolis e clorexidina. Dos 72 isolados, 53 eram C. albicans, 11 C. tropicalis, quatro C. guilhermondii e quatro sugestivas de C. dubliniensis. CFM 90% do extrato de própolis foi de 5% para C. albicans, 20% C. tropicalis, 0,625% C. guilhermondii e 0,312% sugestivas de C. dubliniensis. CFM 90% da clorexidina foi de 0,0018% para C. albicans, 0,012% C. tropicalis, de 0,0018% C. guilhermondii e de 0,00375% sugestivas de C. dubliniensis. Ocorreu inibição das exoenzimas e franjas, em ambos os produtos. Apesar da inibição da clorexidina ser menor que a da própolis, seu uso diário não causa efeitos colaterais indesejáveis como manchas nos dentes e na língua, perda do paladar e sensação de queimação na mucosa bucal.

The activity of propolis extract and chlorhexidine digluconate on Candida sp isolated from oral mucosa of patients in ICU was evaluated. The minimum fungicidal concentrations (MFC) were determined, and also the production of proteinase and phospholipase exoenzymes and the fringe formation. Seventy-two isolates were used and identified by the API 20C AUX® System. The antifungal activity was evaluated by “at base 2” serial microdilution technique. Also the exoenzymes production (proteinase and phospholipase), the fringes formation, before and after being exposed to propolis and chlorhexidine, were analysed. Of 72 isolates, 53 were C. albicans, 11 C. tropicalis, four C. guilhermondii and four suggestive C. dubliniensis. The MFC 90% of propolis extract was 5% C. albicans, 20% C. tropicalis, 0.625% C. guilhermondii; and 0.312% suggestive of C. dubliniensis. MFC 90% of chlorhexidine was 0.0018% C. albicans, 0.012% C. tropicalis, 0.0018% C. guilhermondii and 0.00375% suggestive of C. dubliniensis. The inhibition of exoenzymes and fringes occurred in the both products. Although the inhibition of chlorhexidine is lower than that showed by propolis, its daily use neither cause undesirable side effects as blemishes on the teeth and tongue, nor the loss of the taste and the burning sensation in the oral mucosa.

The Major Chromophore Arising from Glucose Degradation and Oxidative Stress Occurrence during Lens Proteins Glycation Induced by Glucose.

Glucose autoxidation has been proposed as a key reaction associated with deleterious effects induced by hyperglycemia in the eye lens. Little is known about chromophores generated during glucose autoxidation. In this study, we analyzed the effect of oxidative and dicarbonyl stress in the generation of a major chromophore arising from glucose degradation (GDC) and its association with oxidative damage in lens proteins. Glucose (5 mM) was incubated with H2O2 (0.5-5 mM), Cu2+ (5-50 µM), glyoxal (0.5-5 mM) or methylglyoxal (0.5-5 mM) at pH 7.4, 5% O2, 37 °C, from 0 to 30 days. GDC concentration increased with incubation time, as well as when incubated in the presence of H2O2 and/or Cu2+, which were effective even at the lowest concentrations. Dicarbonylic compounds did not increase the levels of GDC during incubations. ¹H, 13C and FT-IR spectra from the purified fraction containing the chromophore (detected by UV/vis spectroscopy) showed oxidation products of glucose, including gluconic acid. Lens proteins solutions (10 mg/mL) incubated with glucose (30 mM) presented increased levels of carboxymethyl-lysine and hydrogen peroxide that were associated with GDC increase. Our results suggest a possible use of GDC as a marker of autoxidative reactions occurring during lens proteins glycation induced by glucose.

Effectiveness of a new non-hydrogen peroxide bleaching agent after single use - a double-blind placebo-controlled short-term study.

INTRODUCTION: Tooth whitening represents perhaps the most common aesthetic procedure in dentistry worldwide. The efficacy of bleaching depends on three aspects: bleaching agent, bleaching method, and tooth color. OBJECTIVE: This in vivo study aimed to examine whitening effects on frontal teeth of the upper and lower jaws using an over-the-counter (OTC) non-hydrogen peroxide bleaching agent in comparison to a placebo after one single use. MATERIAL AND METHODS: Forty subjects (25 female; 15 male) participated in this double-blind randomized placebo-controlled trial. The subjects were randomly allocated to two groups (n=20). The test group received the OTC product (iWhite Instant) and the placebo group received an identically composed product except for the active agents. Each subject was treated with a prefilled tray containing iWhite Instant or the placebo for 20 minutes. The tooth shade of the front teeth (upper and lower jaws) was assessed before (E_0), immediately after (E_1) and 24 h after treatment (E_2), using a shade guide (VITA classical). Statistical testing was accomplished using the Mann-Whitney U test (p<0.001). The dropout rate was 0%. RESULTS: There were no significant differences at E_0 between placebo and test groups regarding the tooth color. Differences in tooth color changes immediately after (ΔE1_0) and 24 h after treatment (ΔE2_0) were calculated for both groups. The mean values (standard deviations) of tooth color changes for ΔE1_0 were 2.26 (0.92) in the test group and 0.01 (0.21) in the placebo group. The color changes for ΔE2_0 showed mean values of 2.15 (1.10) in the test group and 0.07 (0.35) in the placebo group. For ΔE1_0 and ΔE2_0 significant differences were found between the groups. CONCLUSION: In this short-term study, the results showed that a non-hydrogen peroxide bleaching agent has significant whitening effects immediately and 24 h after a single-use treatment.

Effectiveness of a new non-hydrogen peroxide bleaching agent after single use - a double-blind placebo-controlled short-term study

Abstract Tooth whitening represents perhaps the most common aesthetic procedure in dentistry worldwide. The efficacy of bleaching depends on three aspects: bleaching agent, bleaching method, and tooth color. Objective: This in vivo study aimed to examine whitening effects on frontal teeth of the upper and lower jaws using an over-the-counter (OTC) non-hydrogen peroxide bleaching agent in comparison to a placebo after one single use. Material and methods: Forty subjects (25 female; 15 male) participated in this double-blind randomized placebo-controlled trial. The subjects were randomly allocated to two groups (n=20). The test group received the OTC product (iWhite Instant) and the placebo group received an identically composed product except for the active agents. Each subject was treated with a prefilled tray containing iWhite Instant or the placebo for 20 minutes. The tooth shade of the front teeth (upper and lower jaws) was assessed before (E_0), immediately after (E_1) and 24 h after treatment (E_2), using a shade guide (VITA classical). Statistical testing was accomplished using the Mann-Whitney U test (p<0.001). The dropout rate was 0%. Results: There were no significant differences at E_0 between placebo and test groups regarding the tooth color. Differences in tooth color changes immediately after (ΔE1_0) and 24 h after treatment (ΔE2_0) were calculated for both groups. The mean values (standard deviations) of tooth color changes for ΔE1_0 were 2.26 (0.92) in the test group and 0.01 (0.21) in the placebo group. The color changes for ΔE2_0 showed mean values of 2.15 (1.10) in the test group and 0.07 (0.35) in the placebo group. For ΔE1_0 and ΔE2_0 significant differences were found between the groups. Conclusion: In this short-term study, the results showed that a non-hydrogen peroxide bleaching agent has significant whitening effects immediately and 24 h after a single-use treatment.