Efeito da associação do herbicida clomazone a nanoesferas de alginato/quitosana na sorção em solos

Agrochemicals constitute the class of products most commonly found in water resources. Their high level of concentration is due to the fact that less than 0.1% of pesticides applied to crops reach their target. The present work aims to study the sorption of clomazone herbicide (associated or not with nanoparticles). The sorption tests, performed with the 2(4) factorial design, showed that the form of herbicide is the main factor for sorption of clomazone. The application of nanoparticles as delivery system for agrochemicals is a pressing area of study and can contribute for decrease in effects of clomazone in the environment.

Nanopartículas de alginato como sistema de liberação para o herbicida clomazone

In this paper, we describe the preparation of alginate nanoparticles as a delivery system for the herbicide clomazone. Two different methods were investigated and characterized by size distribution, zeta potencial, pH and in vitro release. The alginate/AOT nanoparticles had higher rates of association of the herbicide clomazone than alginate/chitosan nanoparticles. Clomazone release profile, showed a significant difference in release behavior of pure herbicide in solution when compared with herbicide loaded in both alginate nanoparticles. This study is important to construct a biodegradable release system using herbicide for later release into more specific targets, avoiding contamination of environmental matrices.

Cottage cheeses functionalized with fennel and chamomile extracts: comparative performance between free and microencapsulated forms

Globally, there is a trend for healthy food products, preferably incorporating natural bioactive ingredients, replacing synthetic additives. From previous screening studies, extracts of Foeniculum vulgare Mill. (fennel) and Matricaria recutita L. (chamomile) maintained nutritional properties and improved the antioxidant activity of cottage cheese. Nevertheless, this effect was limited to 7 days. Accordingly, aqueous extracts of these plants were microencapsulated in alginate and incorporated into cottage cheese to achieve an extended bioactivity. Plain cottage cheese, and cheese functionalized by direct addition of free decoctions, were prepared and compared. Independently of plant species, "functionalization type" factor did not show a significant effect on the nutritional parameters, as also confirmed in the linear discriminant analysis, where these parameters were not selected as discriminating variables. Furthermore, samples functionalized with microencapsulated extracts showed higher antioxidant activity after the 7th day, thereby demonstrating that the main purpose of this experimental work was achieved.

Quantificação do ião cálcio nas uvas e vinhos brancos por espectroscopia de infravermelho

Com o objetivo de diminuir a incidência das leveduras encapsulas em alginato se aglomerarem na segunda fermentação em garrafa e reduzir custos associados à sua eliminação, pretendeu-se utilizar a metodologia NIR para determinar a quantidade de cálcio no vinho. Foram quantificados outros minerais para avaliar hipotéticos antagonismos iónicos. Observou-se também que este controlo de qualidade poderá ser efetuado no mosto. Atualmente este controlo é realizado por metodologias de análise de referência bastante morosas como EAA. Contudo a metodologia NIR demonstrou ser uma boa alternativa no controlo dos parâ-metros de qualidade na produção de vinho espumante, permitindo a diminuição do tempo de análise e de resíduos. No desenvolvimento dos modelos matemáticos para a calibração do NIR utilizaram-se 79 vinhos brancos e 60 amostras de mosto. Foram desenvolvidos 11 modelos de calibração onde o coeficiente de correlação foi, em aproximadamente 58% dos casos, maior que 0,99; ABSTRACT: In order to reduce the incidence of alginate beads aggregation during the second fermentation in the bottle and to reduce costs associated with their disposal, it was used the NIR technology to quantify calcium content in the wine. Other minerals were also quantified in order to evaluate possible ionic antagonisms. Quality control is usually done in the base wine but it can also be evaluated in the must. Currently this control was carried out by reference analysis methodologies generally rather slow as AAS. However NIR proved to be a good alternative technique in the control of quality parameters of wine production, allowing the reduction of the analysis time and waste. In order to develop mathematical models for the calibration of NIR it was used 79 white wine samples and 60 must samples. Eleven calibration models have been developed, where the correlation coeffi-cient was, in approximately 58% of cases, greater than 0,99.

Ceratonia siliqua L. hydroethanolic extract obtained by ultrasonication: antioxidant activity, phenolic compounds profile and effects in yogurts functionalized with their free and microencapsulated forms

Bioactive extracts were obtained from powdered carob pulp through an ultrasound extraction process and then evaluated in terms of antioxidant activity. Ten minutes of ultrasonication at 375 Hz were the optimal conditions leading to an extract with the highest antioxidant effects. After its chemical characterization, which revealed the preponderance of gallotannins, the extract (free and microencapsulated) was incorporated in yogurts. The microspheres were prepared using an extract/sodium alginate ratio of 100/400 (mg mg(-1)) selected after testing different ratios. The yogurts with the free extract exhibited higher antioxidant activity than the samples added with the encapsulated extracts, showing the preserving role of alginate as a coating material. None of the forms significantly altered the yogurt's nutritional value. This study confirmed the efficiency of microencapsulation to stabilize functional ingredients in food matrices maintaining almost the structural integrity of polyphenols extracted from carob pulp and furthermore improving the antioxidant potency of the final product.

Valorization of the Macroalgae Sargassum Muticum by Enzymatic Hydrolysis, Interest of Surfactants to Improve the Extraction of Phlorotannins and Polysaccharides

The use of surfactants to improve enzymatic hydrolysis of the macroalgae Sargassum muticum has been investigated. Visible absorption spectroscopy has been used to quantify the solubilization of both polysaccharides and phlorotannins in the hydrolysates.   After total extraction, results showed that Sargassum muticum contained 2.74% (expressed in percent of the dry weight of the algae) of phlorotannins whose 32 % were in the cell wall. This result shows that it is important to access to the parietal phlorotannins. To reach this objective, we chose the enzymatic approach for destructurating the cell wall of the algae. The use of 5% dry weight (DW - 5% by weight of hydrolyzed algae) of an enzymatic mix containing a commercial beta-glucanase, a commercial protease and an alginate lyase extracted from Pseudomonas alginovora led after 3 hours of hydrolysis to the solubilization of 2.43% DW polysaccharides and 0.52% DW phlorotannins. The use of 0.5% volume of the surfactant Triton® X-100 with 10% DW of the enzymatic mix has allowed to reaching the value of 2.63% DW of solubilized phlorotannins, that is 96% of the total phenolic content.   The use of non-ionic surfactant, combined to enzymatic hydrolysis, showed an increased efficiency in disrupting cell wall and solubilizing phlorotannins in Sargassum muticum.

Designing Hydrogels that Transform their Shape in Response to Molecular Cues

There has been considerable interest in developing shape-changing soft materials for potential applications in drug delivery, microfluidics and biosensing. These shape- changing materials are inspired by the morphological changes exhibited by plants in nature, such as the Venus flytrap. One specific class of shape-change is that from a flat sheet to a folded structure (e.g., a tube). Such “self-folding” materials are usually composed of polymer hydrogels, and these typically fold in response to external stimuli such as pH and temperature. In order to develop these hydrogels for the previously described applications, it is necessary to expand the range of triggers. The focus of this dissertation is the advancement of shape-changing polymer hydrogels that are sensitive to uncommon cues such as specific biomolecules (enzymes), the substrates for such enzymes, or specific multivalent cations. First, we describe a hybrid gel that responds to the presence of low concentrations of a class of enzymes known as matrix metalloproteinases (MMPs). The hybrid gel was created by utilizing photolithographic techniques to combine two or more gels with distinct chemical composition into the same material. Certain portions of the hybrid gel are composed of a biopolymer derivative with crosslinkable groups. The hybrid gel is flat in water; however, in the presence of MMPs, the regions containing the biopolymer are degraded and the flat sheet folds to form a 3D structure. We demonstrate that hydrogels with different patterns can transform into different 3D structures such as tubes, helices and pancakes. Furthermore, this shape change can be made to occur at physiological concentrations of enzymes. Next, we report a gel with two layers that undergoes a shape change in the presence of glucose. The enzyme glucose oxidase (GOx) is immobilized in one of the layers. GOx catalyzes the conversion of glucose to gluconic acid. The production of gluconic acid decreases the local pH. The decrease in local pH causes one of the layers to swell. As a result, the flat sheet folds to form a tube. The tube unfolds to form a flat sheet when it is transferred to a solution with no glucose present. Therefore, this biomolecule- triggered shape transformation is reversible, meaning the glucose sensing gel is reusable. Furthermore, this shape change only occurs in the presence of glucose and it does not occur in the presence of other small sugars such as fructose. In our final study, we report the shape change of a gel with two layers in the presence of multivalent ions such as Ca2+ and Sr2+. The gel consists of a passive layer and an active layer. The passive layer is composed of dimethylyacrylamide (DMAA), which does not interact with multivalent ions. The active layer consists of DMAA and the biopolymer alginate. In the presence of Ca2+ ions, the alginate chains crosslink and the active layer shrinks. As a result, the gel converts from a flat sheet to a folded tube. What is particularly unusual is the direction of folding. In most cases, when flat rectangular gels fold, they do so about their short-side. However, our gels typically fold about their long-side. We hypothesize that non-homogeneous swelling determines the folding axis.

Dual Quorum Quenching Capsules: Disrupting two bacterial communication pathways that lead to virulence

Healthcare Associated Infections (HAIs) in the United States, are estimated to cost nearly $10 billion annually. And, while device-related infections have decreased, the 60% attributed to pneumonia, gastrointestinal pathogens and surgical site infections (SSIs) remain prevalent. Furthermore, these are often complicated by antibacterial resistance that ultimately cause 2 million illnesses and 23,000 deaths in the US annually. Antibacterial resistance is an issue increasing in severity as existing antibiotics are losing effectiveness, and fewer new antibiotics are being developed. As a result, new methods of combating bacterial virulence are required. Modulating communications of bacteria can alter phenotype, such as biofilm formation and toxin production. Disrupting these communications provides a means of controlling virulence without directly interacting with the bacteria of interest, a strategy contrary to traditional antibiotics. Inter- and intra-species bacterial communication is commonly called quorum sensing because the communication molecules have been linked to phenotypic changes based on bacterial population dynamics. By disrupting the communication, a method called ‘quorum quenching’, bacterial phenotype can be altered. Virulence of bacteria is both population and species dependent; each species will secrete different toxic molecules, and total population will affect bacterial phenotype9. Here, the kinase LsrK and lactonase SsoPox were combined to simultaneously disrupt two different communication pathways with direct ties to virulence leading to SSIs, gastrointestinal infection and pneumonia. To deliver these enzymes for site-specific virulence prevention, two naturally occurring polymers were used, chitosan and alginate. Chitosan, from crustacean shells, and alginate, from seaweed, are frequently studied due to their biocompatibility, availability, self-assembly and biodegrading properties and have already been verified in vivo for wound-dressing. In this work, a novel functionalized capsule of quorum quenching enzymes and biocompatible polymers was constructed and demonstrated to have dual-quenching capability. This combination of immobilized enzymes has the potential for preventing biofilm formation and reducing bacterial toxicity in a wide variety of medical and non-medical applications.

Digestibility of different wheat products in white shrimp Litopenaeus vannamei juveniles

Dry matter, energy, crude protein and amino acid apparent digestibility coefficients (ADCs) were determined in white shrimp juveniles for six wheat products: hard red winter whole grain meal (HWG), Rayon whole grain meal (RWG), Durum whole grain meal (DWG), hard red winter clear flour (HCF), mixed wheat 2nd clear flour (MCF) and semolina (S). The test diets included 30% of the test ingredients and 70% of a ground commercial diet supplemented with 1% chromic oxide and 1% sodium alginate. Amino acid contents in the ingredients, diets and feces were analyzed, and digestibility was determined by difference in order to minimize the impact of endogenous amino acid losses; crude protein and amino acids ADCswere adjusted for dietary preprandial losses in seawater. In general, nutrients digestibility was far higher in the wheat products than in the fish meal-based reference diet. Drymatter and crude proteinADCswere not statistically different amongwheat products (from84 to 96% and from88 to 107% respectively). Energy ADCs were significantly higher for clear flours (96% for HCF and MCF) than forwhole grainmeals and S (from83 to 86%). Total amino acids (TAA) and essentialamino acids (EAA) ADCs, once adjusted for preprandial leaching fromthe experimental diets, ranged from81 to 89% and from 58 to 81% respectively, and were statistically comparable among wheat products. Low Thr ADCs appear as a common feature of the amino acids digestibility profiles for whole grain meals, clear flours, or semolina.

Methotrexate nanoparticle delivery system for treatment of inflammatory bowel disease in pediatric patients

Purpose: To evaluate the efficacy and safety of methotrexate (MTX) nanoparticles in pediatric patients with inflammatory bowel disease (IBD). Methods: In this randomized, open-label clinical study, 28 pediatric patients with moderate to severe IBD were randomly assigned to treatment (MTX nanoparticles,15 mg/week) or control (azathioprine, AZA, 2 mg/kg/day) group. Nanoparticles were synthesized by adding calcium chloride to sodium alginate solution containing MTX, and was further treated with poly-L-lysine aqueous solution. The nanoparticles were evaluated for particle size, zeta potential and drug encapsulation efficacy. Erythrocyte sedimentation rate, C-reactive protein, aspartate aminotransferase, alanine transaminase, and disease activity scores were used to assess IBD remission. Results: Nanoparticle size, zeta potential and encapsulation efficacy were 164.4 ± 6.9 nm, -32.6 ± 3.7 mV, and 97.8 ± 4.2 %, respectively. After 12 weeks of therapy, the mean Pediatric Crohn\'s Disease Activity Index (PCDAI) scores for control and treatment groups were 22.3 ± 2.14 and 16.8 ± 1.87, respectively, while mean Pediatric Ulcerative Colitis Activity (PUCAI) Index scores were 24.3 ± 1.47 and 18.7 ± 1.92, respectively. Eight patients in the treatment and five patients in the control group achieved remission. Biochemical parameters varied significantly between the groups. Conclusion: MTX nanoparticles are safe and more effective than standard first-line IBD therapy. However, further studies are required to determine the suitability of the formulation for therapeutic use.

Polymeric implant of methylprednisolone for spinal injury: preparation and characterization

Purpose: To improve the effectiveness and reduce the systemic side effects of methylprednisolone in traumatic spinal injuries, its polymeric implants were prepared using chitosan and sodium alginate as the biocompatible polymers. Methods: Implants of methylprednisolone sodium succinate (MPSS) were prepared by molding the drug-loaded polymeric mass obtained after ionotropic gelation method. The prepared implants were evaluated for drug loading, in vitro drug release and in vivo performance in traumatic spinal-injury rat model with paraplegia. Results: All the implant formulations were light pale solid matrix with smooth texture. Implants showed 86.56 ± 2.07 % drug loading. Drug release was 89.29 ± 1.25 % at the end of 7 days. Motor function was evaluated in traumatic spinal injury-induced rats in terms of its movement on the horizontal bar. At the end of 7 days, the test group showed the activity score (4.75 ± 0.02) slightly higher than that of standard (4.62 ± 0.25), but the difference was not statistically different (p > 0.05). Conclusion: MPSS-loaded implants produces good recovery in traumatic spinal-injury rats.

Modelling of metal recovery from industrial wastewater using a biopolymer sorbent

Comunicação selecionada e Artigo publicado no Livro de Actas do Congresso

The role of chondrocyte senescence in the pathogenesis of canine osteoarthritis

The aims of this study were to (1) evaluate cellular senescence in chondrocytes from osteoarthritic articular cartilage, (2) investigate the hypothesis that oxidative stress is a feature of canine OA chondrocytes and that oxidative stress contributes to cellular senescence in canine chondrocytes, (3) investigate the hypothesis that osteoarthritic chondrocytes alter the gene expression of adjacent normal chondrocytes in OA joints leading to modulation of genes known to play a role in the pathogenesis of OA and (4) evaluate the presentation of dogs undergoing femoral head excision in veterinary referral practice in the UK as a treatment for osteoarthritis of the coxofemoral joint, and to categorise the distribution and severity of associated pathological lesions. Chondrocytes from osteoarthritic and normal cartilage were examined for levels of senescence. Initially chondrocytes were cultured using an alginate bead culture system, thought to mimic the extracellular matrix of articular cartilage. However, these chondrocytes showed almost no growth as compared to monolayer culture where they grew rapidly. OA chondrocytes entered the senescent state after 1.5 to 4.9 population doublings in monolayer culture, while normal chondrocytes underwent 4.8 to 14.6 population doublings before entering the senescent state. Osteoarthritic chondrocytes had increased levels of markers of cellular senescence (senescence associated beta-galactosidase accumulation and p16 protein accumulation) as compared to normal chondrocytes, suggesting that chondrocyte senescence is a feature of canine osteoarthritis. An experimental model for the induction of oxidative stress in chondrocyte cell culture was developed using tert-Butyl hydroperoxide and total cellular glutathione was measured as an indicator of cellular oxidative stress levels. Experimental induction of oxidative stress in both normal and osteoarthritic chondrocytes in cell culture resulted in increased amounts of cellular senescence, shown by an increase in levels of senescence associated beta-galactosidase accumulation and decreased replicative capacity. Experimental induction of oxidative stress also resulted in altered gene expression of three genes important to the degradation of the extracellular matrix; MMP-13, MMP-3 and Col-3A1, measured by RT-PCR, in normal canine chondrocytes in monolayer cell culture. MMP-3 showed the greatest relative expression change, with a fold-change of between 1.43 and 4.78. MMP-13 had a fold change of 1.16 to 1.38. Col-3A1 was down regulated, with a fold-change of between 0.21 and 0.31. These data demonstrate that experimentally induced oxidative stress in chondrocytes in monolayer culture increases levels of cellular senescence and alters the expression of genes relevant to the pathogenesis of canine OA. Coculture of osteoarthritic chondrocytes with normal canine chondrocytes resulted in gene modulation in the normal chondrocytes. Altered gene expression of ten genes known to play a role in the pathogenesis of osteoarthritis was detected in the normal chondrocytes (fold change shown in brackets); TNF-alpha (11.95), MMP-13 (5.93), MMP-3 (5.48), IL-4 (7.03), IL-6 (5.3), IL-8 (4.92), IL-F3 (4.22), COL-3A1 (4.12), ADAMTS-4 (3.78) and ADAMTS-5 (4.27). In total, 594 genes were significantly modulated suggesting that osteoarthritic chondrocytes contribute to the disease propagation by altering the gene expression of adjacent normal chondrocytes, thus recruiting them into the disease process. Gene expression changes were measured by microarray analysis and validated by RT-PCR and Western blot analysis. An epidemiological study of femoral heads collected from dogs undergoing total hip replacement surgery as a treatment for osteoarthritis of the coxofemoral joint secondary to canine hip dysplasia revealed that there was no characteristic pattern of cartilage lesion for canine hip dysplasia. Severe pathology of the femoral head with cartilage erosion occurred in 63.9% of cases and exposure of subchondral bone in 31.3% of cases. The work presented in this thesis has demonstrated that cellular senescence is a feature of chondrocytes from canine osteoarthritic cartilage and suggests that cellular senescence and oxidative stress play an important role in the pathogenesis of osteoarthritis in dogs.

QUANTIFICATION OF CALCIUM IN SPARKLING WINES BY INFRARED SPECTROSCOPY

Markets are increasingly competitive and the companies feel the urge to improve their manufacturing processes. Blending that with a larger control of quality and safety it was created a need to develop new methods of analysis each time more accurate, faster and with lower costs. Alentejo is a region with a wide variety of soils, most of them are rich in calcium and potassium. In the production of sparkling wine many wineries use encapsulated yeast in alginate beads, instead of the traditional method, champenoise. The first method is faster, allowing a more versatile production, reducing the risk of contamination and features organoleptic characteristics similar to the traditional method (yeast free). However, encapsulated yeast spheres should be only used if the base wine matches a number of features, among them calcium content. In this study the calcium content in the wine was determined by atomic absorption spectroscopy (AAS) and by near-infrared spectroscopy. The AAS is a high sensitivity method clearly produces a reliable result, however it is very time consuming and produces great quantities of environmental waste, therefore the possibility of using near-infrared spectroscopy as a method was studied to be a fast, simple and clean alternative to the AAS. It was obtained a calibration model with a variation coefficient higher than 0.80 which indicates that the near-infrared spectroscopy as an adequately alternative the ASS.

Effect of edible coatings with essential oils on the quality of red raspberries over shelf-life

The objective of the present work was to develop stategies for raising the shelf-life of red raspberries (Rubus idaeus L.). The quality of red raspberries over shelf-life after coated with alginate plus Brazilian Citrus essential oils was evaluated. Edible coatings did not significantly influence the firmness loss, soluble solids content (SCC), and brightness of fruits over time, when compared to control, nevertheless all edible coatings with essential oils induced higher weight loss than those samples in which the essential oils were not incorporated. Fruits coated with alginate plus lime essential oil (0.2%) or orange essential oil (0.1%) after 15 days of storage had less red skin, but were darker than the remaining samples. The less red colour verified in these samples was also coincident with the lower concentration of anthocyanins at the end of the experiment as well as the lower capacity for scavenging ABTS free radicals or quenching singlet oxygen. The edible coatings supplemented with the essential oil of orange either at 0.1 % or 0.2 % were very efficient to control the yeasts and moulds growth after 15 days of storage. To control the development of aerobic mesophilic bacteria the use of essential oil of lemon 0.2% and essential oil of orange 0.1% were the most efficient. The essential oils used in the edible coatings did not significantly change the sensorial properties of the fruit. Cyanidin-3-O-sophoroside, cyanidin-3-O-glucosylrutinoside, cyanidin-3-O-xylosylrutinoside, cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside, pelargonidin-3-O-sophoroside, pelargonidin-3-O-glucosylrutinoside, pelargonidin 3-O-glucoside, pelargonidin 3-O-rutinoside were found in raspberries fruits. An unknown cyanidin derivative was also found in all samples, constituting 27.4% of total anthocyanin content.