Rita Alexandra Manso Araújo

Application of enzymes for textile fibres processing

This review highlights the use of enzymes in the textile industry, covering both current commercial processes and research in this field. Amylases have been used for desizing since the middle of the last century. Enzymes used in detergent formulations have also been successfully used over the past 40 years. The application of cellulases for denim finishing and laccases for decolourization of textile effluents and textile bleaching are the most recent commercial advances. New developments rely on the modification of natural and synthetic fibres. Advances in enzymology, molecular biology and screening techniques provide possibilities for the development of new enzyme-based processes for a more environmentally friendly approach in the textile industry.

Enzymatic surface hydrolysis of poly(ethylene terephthalate) and bis(benzoyloxyethyl) terephthalate by lipase and cutinase in the presence of surface active molecules

A lipase from Thermomyces lanuginosus and cutinases from Thermobifida fusca and Fusarium solani hydrolysed poly(ethylene terephthalate) (PET) fabrics and films and bis(benzoyloxyethyl) terephthalate (3PET) endo-wise as shown by MALDI-Tof-MS, LC-UVD/MS, cationic dyeing and XPS analysis. Due to interfacial activation of the lipase in the presence of Triton X-100, a seven-fold increase of hydrolysis products released from 3PET was measured. In the presence of the plasticizer N,N-diethyl-2-phenylacetamide (DEPA), increased hydrolysis rates of semi-crystalline PET films and fabrics were measured both for lipase and cutinase. The formation of novel polar groups resulted in enhanced dye ability with additional increase in colour depth by 130% and 300% for cutinase and lipase, respectively, in the presence of plasticizer.

Metformin-like effect of salvia officinalis (common sage) : is it useful in diabetes prevention?

Common sage (Salvia officinalis L.) is among the plants that are claimed to be beneficial to diabetic patients, and previous studies have suggested that some of its extracts have hypoglycaemic effects in normal and diabetic animals. In the present study, we aimed to verify the antidiabetic effects of an infusion (tea) of common sage, which is the most common form of this plant consumed. Replacing water with sage tea for 14 d lowered the fasting plasma glucose level in normal mice but had no effect on glucose clearance in response to an intraperitoneal glucose tolerance test. This indicated effects on gluconeogenesis at the level of the liver. Primary cultures of hepatocytes from healthy, sage-tea-drinking rats showed, after stimulation, a high glucose uptake capacity and decreased gluconeogenesis in response to glucagon. Essential oil from sage further increased hepatocyte sensitivity to insulin and inhibited gluconeogenesis. Overall, these effects resemble those of the pharmaceutical drug metformin, a known inhibitor of gluconeogenesis used in the treatment and prevention of type 2 diabetes mellitus. In primary cultures of rat hepatocytes isolated from streptozotocin (STZ)-induced diabetic rats, none of these activities was observed. The present results seem to indicate that sage tea does not possess antidiabetic effects at this level. However, its effects on fasting glucose levels in normal animals and its metformin-like effects on rat hepatocytes suggest that sage may be useful as a food supplement in the prevention of type 2 diabetes mellitus by lowering the plasma glucose of individuals at risk.

Engineered Thermobifida fusca cutinase with increased activity on polyester substrates

A bacterial cutinase from Thermobifida fusca, named Tfu_0883, was genetically modified by site-directed mutagenesis to enhance its activity on poly(ethylene terephthalate) (PET). The new mutations tailored the catalytic site for PET, increasing the affinity of cutinase to this hydrophobic substrate and the ability to hydrolyze it. The mutation I218A was designed to create space and the double mutation Q132A/T101A was designed both to create space and to increase hydrophobicity. The activity of the double mutant on the soluble substrate p-nitrophenyl butyrate increased two-fold compared to wild-type cutinase, while on PET both single and double mutants exhibited considerably higher hydrolysis efficiency. The replacement of specific amino acids at the active site was an effective approach for the improvement of the Tfu_0883 cutinase capacity to hydrolyze polyester surfaces. Thus, this study provides valuable insight on how the function and stability of enzymes can be improved by molecular engineering for their application in synthetic fiber biotransformation.

Proteolytic enzyme engineering: a tool for wool.

One of the goals of protein engineering is to tailor the structure of enzymes to optimize industrial bioprocesses. In the present work, we present the construction of a novel high molecular weight subtilisin, based on the fusion of the DNA sequences coding for Bacillus subtilis prosubtilisin E and for an elastin-like polymer (ELP). The resulting fusion protein was biologically produced in Escherichia coli , purified and used for wool finishing assays. When compared to the commercial protease Esperase, the recombinant subtilisinE-VPAVG(220) activity was restricted to the cuticle of wool, allowing a significant reduction of pilling, weight loss and tensile strength loss of wool fibers. Here we report, for the first time, the microbial production of a functionalized high molecular weight protease for controlled enzymatic hydrolysis of wool surface. This original process overcomes the unrestrained diffusion and extended fiber damage which are the major obstacles for the use of proteases for wool finishing applications.

Functionalization of cellulose acetate fibers with engineered cutinases

In the present work, we describe for the first time the specific role of cutinase on surface modification of cellulose acetate fibers. Cutinase exhibits acetyl esterase activity on diacetate and triacetate of 0.010 U and 0.007 U, respectively. An increase on the hydroxyl groups at the fiber surface of 25% for diacetate and 317% for triacetate, after a 24 h treatment, is estimated by an indirect assay. Aiming at further improvement of cutinase affinity toward cellulose acetate, chimeric cutinases are genetically engineered by fusing the 3′‐end coding sequence with a bacterial or a fungal carbohydrate‐binding module and varying the linker DNA sequence. A comparative analysis of these genetic constructions is presented showing that, the superficial regeneration of cellulose hydrophilicity and reactivity on highly substituted cellulose acetates is achieved by chimeric cutinases.

Biology of human hair : know your hair to control it

Hair can be engineered at different levels--its structure and surface--through modification of its constituent molecules, in particular proteins, but also the hair follicle (HF) can be genetically altered, in particular with the advent of siRNA-based applications. General aspects of hair biology are reviewed, as well as the most recent contributions to understanding hair pigmentation and the regulation of hair development. Focus will also be placed on the techniques developed specifically for delivering compounds of varying chemical nature to the HF, indicating methods for genetic/biochemical modulation of HF components for the treatment of hair diseases. Finally, hair fiber structure and chemical characteristics will be discussed as targets for keratin surface functionalization.

A media pandemic: Influenza A in Portuguese newspapers

Abstract On April 2009, the World Health Organization declared a global pandemic alert as a consequence of the appearance of a new influenza virus, named ‘Influenza A, H1N1’. In Portugal, media coverage on this disease was intense. However, as the number of deaths within Influenza A patients turned out to be much lower than the foreseen statistics of national authorities, the hypothesis of a ‘media pandemic’ was suggested by national opinion makers. Looking for a better understanding of the phenomenon, we conducted a study on media coverage and news sources on Influenza A in Portugal. The study of news sources on health issues is a way of understanding health information and it has been a neglected area on Health Communication. This investigation stood on the examination of 655 articles of three national newspapers, with distinct editorial criteria. The analysis considered six variables: number of sources, geographic location, genre, identification, status, and medical expertise. This task followed a quantitative methodology. The findings confirmed previous noticed trends on health information research: the power of official sources, the complexity of access to medical sources, and the lasting misunderstandings between journalists and the medical community.

In vitro induction of melanin synthesis and extrusion by tamoxifen

Physical appearance has significant importance psychologically and socially, with skin and hair being of prime relevance. Effective ingredients that modulate melanin synthesis are of growing interest. Tamoxifen, a widely used selective oestrogen receptor modulator, SERM, was described occasionally in medical case reports as causing grey hair repigmentation. This work aimed to study, in vitro, the effect of tamoxifen and 4‐hydroxy‐tamoxifen, one of its most bioactive derivatives, on melanin production in human melanocytes.

Power to health reporters: health literacy as a tool to avoid pressures from news sources

The second biggest Legionnaires’ disease outbreak worldwide occurred in Portugal in 2014. It was classified by the WHO as a “great public health emergency,” and it was subject to a unique media coverage in Portugal. The media coverage of this outbreak lasted for 2 weeks, which is not very common in similar cases, and it was characterized by the control of information by official sources. These were put together in a joint task force that disseminated all information. Nonetheless, they did not generate a hegemonic discourse which is usually characteristic of power elites. That happened mostly due to the promotion of health and risk literacy. Through infographics, descriptive maps, and questions and answers, the media were able to generate an alternative discourse to that of official sources. That was the basis of a unique media coverage.