Cristiana Gonçalves

Biological treatment of olive mill wastewater by non-conventional yeasts

The ability of lipolytic yeasts to grow on olive mill wastewater (OMW)-based medium and to produce high-value compounds while degrading this waste, was tested. OMW collected from three-phase olive mills from the North region of Portugal were characterized and used. OMW with COD ranging from 100 g L(-1) to 200 g L(-1) were supplemented with yeast extract and ammonium chloride. Studies of OMW consumption were carried out in batch cultures of Candida rugosa, Candida cylindracea and Yarrowia lipolytica. All strains were able to grow in the OMW-based media, without dilution, to consume reducing sugars and to reduce COD. C. cylindracea was the best strain concerning the lipase production and the reduction of phenolic compounds and COD. For all strains, the phenols degradation was quite difficult, mostly when more easily degradable carbon source is still present in the medium. Among the phenolic compounds tested catechol is the most inhibitory to the cells.

Yarrowia lipolytica lipase production enhanced by increased air pressure

Aims:  To study the cellular growth and morphology of Yarrowia lipolytica W29 and its lipase and protease production under increased air pressures.

Adaptation of dinitrosalicylic acid method to microtiter plates

A microtiter plate adaptation of the well-known dinitrosalicylic acid (DNS) colorimetric method, for measurement of reducing sugars, is described. This method allows a substantial volume reduction of the reagents and a rapid analysis of a large number of samples, having an economic cost benefit and a positive impact on the environment. Therefore, it is well suited as an high-throughput technique for reducing sugars determination.

Rapidly responsive silk fibroin hydrogels as an artificial matrix for the programmed tumor cells death

Timely and spatially-regulated injectable hydrogels, able to suppress growing tumors in response to conformational transitions of proteins, are of great interest in cancer research and treatment. Herein, we report rapidly responsive silk fibroin (SF) hydrogels formed by a horseradish peroxidase (HRP) crosslinking reaction at physiological conditions, and demonstrate their use as an artificial biomimetic three-dimensional (3D) matrix. The proposed SF hydrogels presented a viscoelastic nature of injectable hydrogels and spontaneous conformational changes from random coil to β-sheet conformation under physiological conditions. A human neuronal glioblastoma (U251) cell line was used for screening cell encapsulation and in vitro evaluation within the SF hydrogels. The transparent random coil SF hydrogels promoted cell viability and proliferation up to 10 days of culturing, while the crystalline SF hydrogels converted into β-sheet structure induced the formation of TUNEL-positive apoptotic cells. Therefore, this work provides a powerful tool for the investigation of the microenvironment on the programed tumor cells death, by using rapidly responsive SF hydrogels as 3D in vitro tumor models.

Engineering nanoparticles for targeting rheumatoid arthritis: Past, present, and future trends

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by synovial joint inflammation and cartilage and bone tissue destruction. Although there exist some treatment strategies for RA, they are not completely safe and effective. Therefore, it is important to develop and test new drugs for RA that specifically target inflamed/swollen joints and simultaneously attenuate other possible damages to healthy tissues. Nanotechnology can be a good alternative to consider when envisioning precise medication for treating RA. Through the use of nanoparticles, it is possible to increase bioavailability and bioactivity of therapeutics and enable selective targeting to damaged joints. Herein, recent studies using nanoparticles for the treatment of RA, namely with liposomes, polymeric nanoparticles, dendrimers, and metallic nanoparticles, have been reviewed. These therapeutic strategies have shown great promise in improving the treatment over that by traditional drugs. The results of these studies confirm that feasibility of the use of nanoparticles is mainly due to their biocompatibility, low toxicity, controlled release, and selective drug delivery to inflamed tissues in animal RA models. Therefore, it is possible to claim that nanotechnology will, in the near future, play a crucial role in advanced treatments and patient-specific therapies for human diseases such as RA.

Biological performance of a promising Kefiran-biopolymer with potential in regenerative medicine applications: a comparative study with hyaluronic acid

AbstractKefiran from kefir grains, an exopolysaccharide (EPS) produced by lactic acid bacteria (LAB), has received an increasing interest because of its safe status. This natural biopolymer is a water-soluble glucogalactan with probed health-promoting properties. However, its biological performance has yet to be completely recognized and properly exploited. This research was carried out to evaluate the in vitro antioxidant and the in vitro anti-inflammatory properties of Kefiran biopolymer. Regarding antioxidant activity, the results demonstrated that the Kefiran extract possessed the strongest reducing power and superoxide radical scavenging, over hyaluronic acid (HA, gold standard viscosupplementation treatment). This exopolysaccharide showed a distinct antioxidant performance in the majority of in vitro working mechanisms of antioxidant activity comparing to HA. Moreover, Kefiran presented an interesting capacity to scavenge nitric oxide radical comparing to the gold standard that did not present any potency. Finally, the cytotoxic effects of Kefiran extracts on hASCs were also performed and demonstrated no cytotoxic response, ability to improve cellular function of hASCs. This study demonstrated that Kefiran represented a great scavenger for reactive oxygen and nitrogen species and showed also that it could be an excellent candidate to promote tissue repair and regeneration.

Kefiran biopolymer: Evaluation of its physicochemical and biological properties

Kefiran, an exopolysaccharide produced by lactic acid bacteria, has received a great interest due to a variety of health claims. In this study, we aim to investigate the physicochemical and biological properties of Kefiran polysaccharide extracted from Portuguese kefir grains. The kefir growth rate was about 56% (w/w) at room temperature and the kefir pH after 24 h was about 4.6. The obtained yield of Kefiran polysaccharide extracted from the kefir grains was about 4.26% (w/w). The Kefiran structural features were showed in the 1H nuclear magnetic resonance spectrum. The bands observed in the infrared spectrum confirmed that the Kefiran had a β-configuration; and the X-ray photoelectron spectroscopy analysis confirmed the structure and composition of Kefiran and revealed a C/O atomic ratio of 1.46. Moreover, Kefiran showed an average molecular weight (Mw) of 534 kDa and a number-average molecular weight (Mn) of 357 kDa. Regarding the rheological data obtained, Kefiran showed an interesting adhesive performance accompanied by a pseudoplastic behavior, and the extrusion force of Kefiran was 1 N. Furthermore, Kefiran exhibited a higher resistance to hyaluronidase degradation than hyaluronic acid. Finally, Kefiran showed a lack of cytotoxic response through its ability to support metabolic activity and proliferation of L929 cells, and had no effect on these cells’ morphology. Our research suggested that Kefiran polymer has attractive and interesting properties for a wide range of biomedical applications, such as tissue engineering and regenerative medicine.

Advances in biomaterials for the treatment of articular cartilage defects

The management of cartilage defects is one of the most challenging problems for public and medical communities. The complete repairing of the damaged cartilage is a complex procedure, since articular cartilage is characterized by a poor vascularization (absence of blood vessels and nerve source), which limits the capacity to repair itself. Cartilage tissue engineering and regenerative medicine are relatively novel areas of research and may hold the key to the successful treatment of cartilage diseases and disorders. Materials such as natural and synthetic biomaterials have been explored to recreate the microarchitecture of articular cartilage through multilayered biomimetic scaffolds. In this chapter, an overview is given of the natural and synthetic biomaterials used on cartilage repair, describing the procedures to obtain these biomaterials, their chemical structure, their modifications to enhance their properties, and also their medical applications.

Synovial knee joint

The knee is a synovial knee joint that allows flexion, extension and also a slight ability to rotate medially and laterally, being able to move on two planes, being known as a modified hinge joint. The main features of a synovial joint are the articulating cartilage, the joint capsule, the joint cavity, the bursae and the ligaments. The joint capsule is composed by the synovium and a fibrous capsule, keeping the synovial fluid that fills the joint cavity inside the joint. The most common injuries or diseases that affects this complex biomechanical system are arthritis, bursitis and dislocations. In fact, the synovium the central area of pathology in a number of inflammatory joint diseases, such as rheumatoid arthritis (RA) and spondyloarthritis (SpA).

MS269 PLASMA AMINOTHIOLS STATUS IN THE POPULATION OF THE ISLAND OF S ÃO JORGE (THE AZORES' ARCHIPELAGO, PORTUGAL)

Aim: To determine frequency of microalbuminuria in metabolic centre outpatients with one or more risk factors for cardiovascular diseases. Metods: For the examination of microalbuminuria we colleced 2 morning urine sample. We determined concentration of albumin by immunoturbidimetry (normal value 2.8–22.8mg/mmol creatinine). Data are expressed (if not stated otherwise) as median (interquartile range). For statistical comparisons we used Wilcoxon unpaired test. Results: In the period October − November 2008, we measured microalbuminuria in 174 metabolic centre outpatients. 165 (95%) patients were treated hypolipidemic drugs, 124 (71%) patients were on antihypertensive therapy. 82 (47%) were patients with metabolic syndrome. Microalbuminuria was positive in 18 patients (10%); 11 (61%) of them had metabolic syndrome. The difference between microalbuminuria in patients with metabolic syndrome (0.7 [0.4−1.6] mg/mmol crea) and without metabolic syndrome (0.5 [0.3−1.0] mg/mmol crea) was statistically significant (p < 0.05 95%CI 0.0001−1.3). Various other risk factors were: hypertension 68%, waist circuit (males 102 cm, females 88 cm) 48%, triglycerides (> 1.7mmol/l) 48%, HDL cholesterol (< 1.0mmol/l for males, 1.3 mmol/l for females) 15%, impaired glucose tolerance 22%, diabetes mellitus 10%. Conclusion: Low incidence of microalbuminuria in metabolic centre outpatients is probably due to effective farmacotherapy and life-style intervention and certifies positive influence on risk factors of atherosclerosis. Our plan for near future − to examine microalbuminuria in newly acquired outpatients without any therapy and compare them to patients with established therapy.