Recent advances in antimicrobial surfaces for urinary catheters

Although urinary catheters (UCs) are one of the most used medical devices, they are related to a high incidence of urinary tract infections resulting from microbial colonization and consequent biofilm development on UC surfaces. Currently, a panoply of antimicrobial and antifouling surfaces is available to solve this longstanding problem. However, despite their high performance, these surfaces are still far from clinical application. In this current opinion article, we evaluate and critically discuss the antimicrobial performance and applicability of UC surfaces with different antibiofilm mechanisms. It is our opinion that either killing or anti-adhesive coatings are promising in controlling infection development. However, most of them are more effective in delaying microbial adhesion rather than preventing it

Isolation of a seed coagulant Moringa oleifera lectin

In this work hemagglutinating activity (HA) was investigated in distinct Moringa oleifera tissue extracts. A new lectin from seeds (cMoL) was purified and characterized; hemagglutinating and coagulating activities were evaluated. HA was detected in 0.15 M NaCl extracts from flowers and rachis inflorescence (5%, w/v), seeds, leaves, fundamental tissue of stem and steam bark (10%, w/v). cMoL isolated after saline extraction and guar gel column chromatography was active at pH range 4.0–9.0 agglutinating erythrocytes from rabbit and human blood types. Extracts of tissues and cMoL activities were carbohydrate inhibited; azocasein and asialofetuin abolished cMoL HA. The lectin was thermostable at 100 °C during 7 h. Polyacrylamide gel electrophoresis under reduced conditions revealed a main polypeptide band of 26.5 kDa; native basic cMoL was detected as a unique band. Seed lectin preparations and cMoL showed coagulant activity, similar to aluminium sulphate, the coagulant most widely used in water treatment.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Ciência e Tecnologia do Estado de Pernambuco (FACEPE)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Científico e Tecnológico (CNPq

Heme oxygenase 1 improves glucoses metabolism and kidney histological alterations in diabetic rats

One important concern in the treatment of diabetes is the maintenance of glycemic levels and the prevention of diabetic nephropathy. Inducible heme oxygenase 1 (HO-1) is a rate-limiting enzyme thought to have antioxidant and cytoprotective roles. the goal of the present study was to analyze the effect of HO-1 induction in chronically hyperglycemic rats. the hyperglycemic rats were divided into two groups: one group, called STZ, was given a single injection of streptozotocin; and the other group was given a single streptozotocin injection as well as daily injections of hemin, an HO-1 inducer, over 60 days (STZ + HEME). A group of normoglycemic, untreated rats was used as the control (CTL).Body weight, diuresis, serum glucose levels, microalbuminuria, creatinine clearance rate, urea levels, sodium excretion, and lipid peroxidation were analyzed. Histological alterations and immunohistochemistry for HO-1 and inducible nitric oxide synthase (iNOS) were assessed. After 60 days, the STZ group exhibited an increase in blood glucose, diuresis, urea, microalbuminuria, and sodium excretion. There was no weight gain, and there was a decrease in creatinine clearance in comparison to the CTL group. in the STZ + HEME group there was an improvement in the metabolic parameters and kidney function, a decrease in blood glucose, serum urea, and microalbuminuria, and an increase of creatinine clearance, in comparison to the STZ group.There was glomerulosclerosis, collagen deposition in the STZ rats and increase in iNOS and HO-1 expression. in the STZ + HEME group, the glomerulosclerosis and fibrosis was prevented and there was an increase in the expression of HO-1, but decrease in iNOS expression and lipid peroxidation. in conclusion, our data suggest that chronic induction of HO-1 reduces hyperglycemia, improves glucose metabolism and, at least in part, protects the renal tissue from hyperglycemic injury, possibly through the antioxidant activity of HO-1.Universidade Federal de São Paulo UNIFESP, Div Nephrol, Dept Med, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Morphol Dept, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Div Nephrol, Dept Med, São Paulo, BrazilUniversidade Federal de São Paulo UNIFESP, Morphol Dept, São Paulo, BrazilWeb of Scienc

Oriented immobilization of Pep19-2.5 on antifouling brushes suppresses the development of Staphylococcus aureus biofilms

Bacterial colonization of indwelling medical devices poses a danger to the patient and is a tremendous economic burden that costs billions of dollars to the healthcare system. Thus, it is essential to develop an effective mechanism that prevents the attachment of bacteria to the surface in combination with bactericidal strategies to kill them in direct contact. In this work, we combine the repellent/antifouling properties of polymer brushes with the antimicrobial activity of the synthetic peptide Pep19-2.5 and test its efficacy to inhibit Staphylococcus aureus biofilm formation. To tackle this, we utilized hierarchical polymer brushes, where the bottom block provides an effective barrier against adhesion while the top block provides functional groups for the immobilization of active molecules. Further, these polymer brushes were decorated with dibenzocyclooctine (DBCO)-functionalized Pep19-2.5 using strain-promoted alkyne-azide cycloaddition (SPAAC). This click chemistry proceeds very fast and does not require any catalyst, which is crucial for biomedical applications. The obtained coating was not only able to decrease the number of freely planktonic bacteria in the surrounding media (by 52.5%) but also inhibit the development of S. aureus biofilm by reducing the number of total, viable, and viable but non-culturable (VBNC) cells (up to 58%, 66%, and 70% respectively) and reduce the biovolume and thickness. Conversely, this coating does not exert any cytotoxic effect on Normal Human Dermal Fibroblasts (NHDF) cells. Thus, the combination of hierarchical polymer brushes with Pep19-2.5 is a promising approach to fight medical biofilms without affecting surrounding tissues

Production and Characterization of Graphene Oxide Surfaces against Uropathogens

Graphene and its functionalized derivatives have been increasingly applied in the biomedical field, particularly in the production of antimicrobial and anti-adhesive surfaces. This study aimed to evaluate the performance of graphene oxide (GO)/polydimethylsiloxane (PDMS) composites against Staphylococcus aureus and Pseudomonas aeruginosa biofilms. GO/PDMS composites containing different GO loadings (1, 3, and 5 wt.%) were synthesized and characterized regarding their morphology, roughness, and hydrophobicity, and tested for their ability to inhibit biofilm formation under conditions that mimic urinary tract environments. Biofilm formation was assessed by determining the number of total and culturable cells. Additionally, the antibacterial mechanisms of action of GO were investigated for the tested uropathogens. Results indicated that the surfaces containing GO had greater roughness and increased hydrophobicity than PDMS. Biofilm analysis showed that the 1 wt.% GO/PDMS composite was the most effective in reducing S. aureus biofilm formation. In opposition, P. aeruginosa biofilms were not inhibited by any of the synthesized composites. Furthermore, 1% (w/v) GO increased the membrane permeability, metabolic activity, and endogenous reactive oxygen species (ROS) synthesis in S. aureus. Altogether, these results suggest that GO/PDMS composites are promising materials for application in urinary catheters, although further investigation is required.</p

Concepções alternativas dos Alunos de Ensino Médio sobre ácidos e bases

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Moringa oleifera lectin and binding affinity to humic acids : application to water treatment

Humic acids, natural organic matter, constitute a problem in water treatment; they react with chlorine forming undesirable disinfection byproducts. The aim of this work was the purification of a saline soluble Moringa oleifera lectin (SSMoL) and characterization of its affinity to humic acids. SSMoL isolation included extraction of seed flour, saline fractionation and guar gel chromatography. Hemagglutinating activity (HA) of extract (E), fraction (0-60F) and SSMoL was assessed with rabbit erythrocytes. HA inhibitions were done with humic acid, carbohydrates, glycoproteins and halogenated organic compounds. Diffusion experiments with humic acid and lectin preparations were performed in agarose gel. Basic SSMoL showed two polypeptide bands with ß-mercapthoethanol treatment. SSMoL HA with humic acid decreased from 512-1 to 32-1. Similar results were obtained with E and 0-60F. SSMoL was partially inhibited by carbohydrates and glycoproteins; azocasein abolished SSMoL activity. SSMoL HA was not altered with trichloroacetic and dicholoroacetic acids, or chloroform. Precipitation bands were observed in diffusion gel. The present study foresees a future application of SSMoL in water treatment to remove humic acids

Cladosporium tenuissimum URM 7803: a promising new β-galactosidase producer

The Cladosporium genus, defined by Link in 1816, is one of the largest and most heterogeneous Hyphomycetes genus. It comprises more than 189 species still rarely explored biotechnologically. One of the most studied microbial enzymes, -galactosidase is a glycoside hydrolase enzyme that catalyzes the hydrolysis of -galactosides into monosaccharides through the breaking of a glycosidic bond. Recently, new studies comprising new microbial sources of -galactosidase, presenting biotechnologically interesting characteristics, have been encouraged. In this context, the present study evaluated the production of -galactosidase by a new isolate of Cladosporium tenuissimum. A C. tenuissimum inoculum was prepared adding 107 spore/mL in sterile saline solution 0.85% (w/v) NaCl containing 0.01% (w/v) Tween 80 and added to fermentation medium for enzyme production. The fermentation medium, composed of (% w/v): lactose (2), peptone (0.4), yeast extract (0.4) and salts (KH2PO4 (0.2), Na2HPO4.12H2O (0.8) and MgSO4.7H2O (0.025), pH 6.5, was maintained at 28° C and 180 rpm for 13 days. One sample (50 mL erlenmeyer) was removed every 24 hours and -galactosidase activity was evaluated using ONPG (ortho-Nitrophenyl--galactoside) method. The results showed maximum -galactosidase production by C. tenuissimum URM 7803 on thirteenth day, displayed enzymatic activity of 462.13 U/mL. The C. tenuissimum URM 7803 isolate proved to be a powerful new -galactosidase producer with potential application for food processing.info:eu-repo/semantics/publishedVersio