Improved L-Asparaginase Properties and Reusability by Immobilization onto Functionalized Carbon Xerogels

Enzyme immobilization can offer a range of significant advantages, including reusability, and increased selectivity, stability, and activity. In this work, a central composite design (CCD) of experiments and response surface methodology (RSM) were used to study, for the first time, the L-asparaginase (ASNase) immobilization onto functionalized carbon xerogels (CXs). The best results were achieved using CXs obtained by hydrothermal oxidation with nitric acid and subsequent heat treatment in a nitrogen flow at 600 degrees C (CX-OX-600). Under the optimal conditions (81 min of contact time, pH 6.2 and 0.36 g/L of ASNase), an immobilization yield (IY) of 100 % and relative recovered activity (RRA) of 103 % were achieved. The kinetic parameters obtained also indicate a 1.25-fold increase in the affinity of ASNase towards the substrate after immobilization. Moreover, the immobilized enzyme retained 97 % of its initial activity after 6 consecutive reaction cycles. All these outcomes confirm the promising properties of functionalized CXs as support for ASNase, bringing new insights into the development of an efficient and stable immobilization platform for use in the pharmaceutical industry, food industry, and biosensors. The development of an efficient strategy for immobilizing L-asparaginase enzyme onto functionalized carbon xerogels is the focus of this work. The results reveal the importance of tuning the surface chemistry of the materials and prove the enhanced activity, higher affinity with the substrate, and reusability of L-asparaginase achieved through immobilization.+ imag

Unveiling the Influence of Carbon Nanotube Diameter and Surface Modification on the Anchorage of L-Asparaginase

L-asparaginase (ASNase, EC 3.5.1.1) is an amidohydrolase enzyme known for its anti-cancer properties, with an ever-increasing commercial value. Immobilization has been studied to improve the enzyme's efficiency, enabling its recovery and reuse, enhancing its stability and half-life time. In this work, the effect of pH, contact time and enzyme concentration during the ASNase physical adsorption onto pristine and functionalized multi-walled carbon nanotubes (MWCNTs and f-MWCNTs, respectively) with different size diameters was investigated by maximizing ASNase relative recovered activity (RRA) and immobilization yield (IY). Immobilized ASNase reusability and kinetic parameters were also evaluated. The ASNase immobilization onto f-MWCNTs offered higher loading capacities, enhanced reusability, and improved enzyme affinity to the substrate, attaining RRA and IY of 100 and 99%, respectively, at the best immobilization conditions (0.4 mg/mL of ASNase, pH 8, 30 min of contact time). In addition, MWCNTs diameter proved to play a critical role in determining the enzyme binding affinity, as evidenced by the best results attained with f-MWCNTs with diameters of 10-20 nm and 20-40 nm. This study provided essential information on the impact of MWCNTs diameter and their surface functionalization on ASNase efficiency, which may be helpful for the development of innovative biomedical devices or food pre-treatment solutions

Hypericum sp.: essential oil composition and biological activities

Phytochemical composition of Hypericum genus has been investigated for many years. In the recent past, studies on the essential oils (EO) of this genus have been progressing and many of them have reported interesting biological activities. Variations in the EO composition of Hypericum species influenced by seasonal variation, geographic distribution, phenological cycle and type of the organ in which EO are produced and/or accumulated have also been reported. Although many reviews attributed to the characterization as well as biological activities of H. perforatum crude extracts have been published, no review has been published on the EO composition and biological activities of Hypericum species until recently (Crockett in Nat Prod Commun 5(9):1493–1506, 2010; Bertoli et al. in Global Sci Books 5:29–47, 2011). In this article, we summarize and update information regarding the composition and biological activities of Hypericum species EO. Based on experimental work carried out in our laboratory we also mention possible biotechnology approaches envisaging EO improvement of some species of the genus.Fundação para a Ciência e a Tecnologia (FCT) - project PTDC/AGR AAM/70418/2006, SFRH/BD/ 13283/2003

Validação da Échelle Douleur Inconfort Nouveau-Né para a cultura brasileira

RESUMO Objetivo Avaliar a confiabilidade e a validade da versão brasileira da Échelle Douleur Inconfort Nouveau-Né, que mensura a dor prolongada em recém-nascidos. Método Estudo metodológico realizado junto com recém-nascidos. Para a coleta foram utilizadas as versões brasileiras da Échelle Douleur Inconfort Nouveau-Né e da Children’s and Infants’ Postoperative Pain Scale. Para a confiabilidade, foram consideradas a equivalência, mensurada pela concordância entre observadores, e a homogeneidade. Para avaliar a validade, foi considerada a abordagem de construto convergente correlacionando as versões brasileiras da Échelle Douleur Inconfort Nouveau-Né e da Children’s and Infants’ Postoperative Pain Scale. Resultados Compuseram a amostra final 96 recém-nascidos. Na avaliação da confiabilidade, o coeficiente de concordância entre observadores variou entre 0,64 e 0,85 para os itens que compõem o instrumento e 0,96 para o escore total. O alfa de Cronbach foi de 0,82. Na avaliação da validade convergente, o coeficiente de correlação de Spearman entre os valores encontrados para as duas escalas foi de 0,79 (p< 0,0001). Conclusão A versão brasileira da Échelle Douleur Inconfort Nouveau-Né é um instrumento confiável e válido para avaliar a dor prolongada em recém-nascidos

Social representation of domestic violence against women among Nursing Technicians and Community Agents

OBJECTIVE To analyze the social representations of the Nursing Technicians and Community Health Agents about domestic violence against women. METHOD A qualitative study carried out in the city of Rio Grande, RS, in which evocations and interviews were collected between July and November 2013. For the treatment of data were used the EVOC 2005 software and the context analysis. RESULT It is a structured representation, in which the central nucleus contains conceptual, imaging and attitudinal elements, namely: abuse, aggression, physical aggression, cowardice and lack of respect. Such terms were present in the context of the interviews. The professionals acknowledged that violence is not limited to physical aspects and were judgemental about the acts of the aggressor. CONCLUSION This knowledge may enable the problematization of the studied phenomenon with the team, and facilitate the search for prevention and intervention strategies for victims, offenders and managers of health services