Universidade Federal de Santa Catarina

About: Universidade Federal de Santa Catarina is a education organization based out in Florianópolis, Brazil. It is known for research contribution in the topics: Population & Context (language use). The organization has 28408 authors who have published 55433 publications receiving 714461 citations.

A review on enzymatic synthesis of aromatic esters used as flavor ingredients for food, cosmetics and pharmaceuticals industries

Abstract: Background Many sectors of industry, mainly food, cosmetics and pharmaceutics, have increased their interest in esters due to their flavor property. Flavor esters that possess an aromatic ring in their molecular structure are also known as aromatic esters. These esters are widely found in nature (fruits and plants) and the synthetic (i.e. via chemical) and natural routes (i.e. via direct extraction from nature or via biotechnology) are suitable for their biocatalysis. Scope and approach In this context, from the industrial point of view, enzyme-catalyzed reactions are the most economical approach to reach final green products with no toxicity and no harm to human health. The present article gives an overview of the aromatic esters synthesis, considering the main effects in the reaction media conditions and enzymes used. This review also describes applied trends in enzymatic-catalyzed reactions, pointing alternatives to production, like ultrasound-assisted reactions and process optimization of aromatic esters. Furthermore, this work presents perspectives concerning the biological potential of these esters and recent advances in their encapsulation. Key findings and conclusions Lipases play an important role in the aromatic esters production, with several advantages over synthetic route. Lipase-catalyzed reactions usually follows Ping-Pong Bi-Bi or ternary complex (order Bi-Bi) mechanism. The study of the process parameters and their interaction are very important to understand the system optimization and achieve the maximum reaction yield to scale up. Aromatic esters can present some biological activities, in addition to their fragrances, which increases the interest in the encapsulation of these compounds.

Preparation and characterization of quaternary chitosan salt: adsorption equilibrium of chromium(VI) ion

Abstract: Quaternary chitosan salt (QCS) was synthesized with the aid of a substituent containing a quaternary ammonium group, glycidyl trimethyl ammonium chloride. The polymer was characterized by IR, 1H NMR, TGA and amount of quaternary ammonium groups. The studies on Cr(IV) ion adsorption equilibrium were conducted taking into account contact time, pH and amount of cross-linked QCS. The kinetic adsorption mechanism of the Cr(VI) ion was best described by the pseudo-second-order equation with a rate constant of 1.0 × 10−3 mg/g min. The Langmuir isotherm model was employed in order to adjust adsorption data, and the capacity was shown to depend on pH. The adsorption capacity for Cr(VI) at pH 9.0 was 30.2 mg/g (0.58 mmol/g), while at pH 4.5 the capacity was 68.3 mg/g (1.31 mmol/g). Cr(VI) ions can be eluted from cross-linked QCS by treatment with a 1 mol/l solution of NaCl/NaOH showing an efficiency of more than 95%.

The metabolite BH4 controls T cell proliferation in autoimmunity and cancer

Abstract: Genetic regulators and environmental stimuli modulate T cell activation in autoimmunity and cancer. The enzyme co-factor tetrahydrobiopterin (BH4) is involved in the production of monoamine neurotransmitters, the generation of nitric oxide, and pain1,2. Here we uncover a link between these processes, identifying a fundamental role for BH4 in T cell biology. We find that genetic inactivation of GTP cyclohydrolase 1 (GCH1, the rate-limiting enzyme in the synthesis of BH4) and inhibition of sepiapterin reductase (the terminal enzyme in the synthetic pathway for BH4) severely impair the proliferation of mature mouse and human T cells. BH4 production in activated T cells is linked to alterations in iron metabolism and mitochondrial bioenergetics. In vivo blockade of BH4 synthesis abrogates T-cell-mediated autoimmunity and allergic inflammation, and enhancing BH4 levels through GCH1 overexpression augments responses by CD4- and CD8-expressing T cells, increasing their antitumour activity in vivo. Administration of BH4 to mice markedly reduces tumour growth and expands the population of intratumoral effector T cells. Kynurenine—a tryptophan metabolite that blocks antitumour immunity—inhibits T cell proliferation in a manner that can be rescued by BH4. Finally, we report the development of a potent SPR antagonist for possible clinical use. Our data uncover GCH1, SPR and their downstream metabolite BH4 as critical regulators of T cell biology that can be readily manipulated to either block autoimmunity or enhance anticancer immunity. Tetrahydrobiopterin (BH4) is an enzyme co-factor that is involved in the nervous system; it is shown here to also function in T cell activation and proliferation, with roles in autoimmunity, allergic inflammation and cancer.

Expression of FOXA1 and GATA-3 in breast cancer: the prognostic significance in hormone receptor-negative tumours

Abstract: The expression of additional genes, other than oestrogen receptor (ER), may be important to the hormone-responsive phenotype of breast cancer. Microarray analyses have revealed that forkhead box A1 (FOXA1) and GATA binding protein 3 (GATA-3) are expressed in close association with ERα, both encoding for transcription factors with a potential involvement in the ERα-mediated action in breast cancer. The purpose of this study was to explore if the expression of FOXA1 and GATA-3 may provide an opportunity to stratify subsets of patients that could have better outcome, among the ERα-negative/poor prognosis breast cancer group. We evaluate FOXA1 and GATA-3 expression in 249 breast carcinomas by immunohistochemistry, associating it with breast cancer molecular markers, clinicopathological features and patient's survival. The clinicopathological features and immunohistochemical markers of the tumours were compared using the chi-square test and ANOVA. Disease-free survival was analysed through Kaplan–Meier survival curves and Cox regression. FOXA1 expression was demonstrated in 42% of invasive carcinomas, while GATA-3 was detected in 48% of the cases. FOXA1 expression was inversely associated with tumour size, Nottingham Prognostic Index, histological grade, lymph vascular invasion, lymph node stage and human epidermal growth factor receptor-2 (HER-2) overexpression, while GATA-3 expression showed inverse association with histological grade and HER-2. Both FOXA1 and GATA-3 were directly associated with ERα and progesterone receptor. Among FOXA1-positive tumours, 83.1% are comprised in the luminal A subtype, similar to GATA-3 where 87.7% of positive tumours were classified within this molecular subtype. In the subset of ERα-negative patients, those who were FOXA1-negative had a 3.61-fold increased risk of breast cancer recurrence when compared with the FOXA1-positive. FOXA1 was a significant predictor of good outcome in breast cancer, whereas GATA-3 was an important luminal marker. The expression of FOXA1 may be used for risk stratification among ERα-negative patients.

Aetiology and rates of treatment of traumatic dental injuries among 12-year-old school children in a town in southern Brazil.

Abstract: The objective of this study was to assess the prevalence, aetiology, place of occurrence and rates of treatment of traumatic dental injuries (TDI) among 12-year-old schoolchildren in Herval D'Oeste, Brazil. A cross-sectional survey was carried out through clinical examination of upper and lower permanent incisors and interviews with 297, 12-year-old schoolchildren enrolled in public and private schools. Intra-examiner diagnosis variability, measured by kappa values on tooth-by-tooth basis was above 0.7. The prevalence of TDI was 17.3% (95% CI 12.7-21.9). Children who had an incisal overjet size >5 mm were 3.5 (95% CI 1.5-8.1) times more likely to have TDI than children who had an incisal overjet of <5 mm (P = 0.005). The most common type of injury found was enamel fracture alone. Of the total of 87 traumatized teeth, only 27.6% were treated. Acid etch restorations were the most common treatment provided. Acid etch restorations were the most common type of treatment needed. The majority of the cases of TDI occurred at home (17.8%) and at school (17.8%). Collisions (24.5%), mainly with doors, and physical leisure activities (20.0%) such as cycling and playing soccer were the main activities related to TDI aetiology. It can be concluded that there is a great treatment need reflecting neglect of TDI treatment. The main causes of TDI were collisions and physical leisure activities.