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Applied Molecular Biosciences Unit
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Exploring the multifaceted potential of a peptide fraction derived from Saccharomyces cerevisiae metabolism: antimicrobial, antioxidant, antidiabetic, and anti-inflammatory properties
Publication . Branco, Patrícia; Maurício, Elisabete Muchagato; Costa, Ana; Ventura, Diogo; Roma-Rodrigues, Catarina; Duarte, Maria Paula; Fernandes, Alexandra R.; Prista, Catarina
The rising demand for minimally processed, natural, and healthier food products has
led to the search for alternative and multifunctional bioactive food components. Therefore, the
present study focuses on the functional proprieties of a peptide fraction derived from Saccharomyces
cerevisiae metabolism. The antimicrobial activity of the peptide fraction is evaluated against various
foodborne pathogens, including Candida albicans, Candida krusei, Escherichia coli, Listeria monocytogenes,
and Salmonella sp. The peptide fraction antioxidant properties are assessed using FRAP and
DPPH scavenging capacity assays. Furthermore, the peptide fraction’s cytotoxicity is evaluated in
colorectal carcinoma and normal colon epithelial cells while its potential as an antidiabetic agent
is investigated through -amylase and -glucosidase inhibitory assays. The results demonstrate
that the 2–10 kDa peptide fraction exhibits antimicrobial effects against all tested microorganisms,
except C. krusei. The minimal inhibitory concentration for E. coli, L. monocytogenes, and Salmonella
sp. remains consistently low, at 0.25 mg/mL, while C. albicans requires a higher concentration of
1.0 mg/mL. Furthermore, the peptide fraction displays antioxidant activity, as evidenced by DPPH
radical scavenging activity of 81.03%, and FRAP values of 1042.50 32.5 M TE/mL at 1.0 mg/mL.
The peptide fraction exhibits no cytotoxicity in both tumor and non-tumoral human cells at a concentration
up to 0.3 mg/mL. Moreover, the peptide fraction presents anti-inflammatory activity,
significantly reducing the expression of the TNF gene by more than 29.7% in non-stimulated colon
cells and by 50% in lipopolysaccharide-stimulated colon cells. It also inhibits the activity of the
carbohydrate digestive enzymes -amylase (IC50 of 199.3 0.9 g/mL) and -glucosidase (IC20 of
270.6 6.0 g/mL). Overall, the findings showed that the peptide fraction exhibits antibacterial,
antioxidant, anti-inflammatory, and antidiabetic activity. This study represents a step forward in the
evaluation of the functional biological properties of S. cerevisiae bioactive peptides.
Tackling Humidity with Designer Ionic Liquid-Based Gas Sensing Soft Materials
Publication . Esteves, C.; Palma, S.I.C.J.; Costa, H.M.A.; Alves, C.; Santos, G.M.C.; Ramou, E.; Carvalho, A.L.; Delgado Alves, Vitor; Roque, A.C.A.
Relative humidity is simultaneously a sensing target and a contaminant in gas
and volatile organic compound (VOC) sensing systems, where strategies to
control humidity interference are required. An unmet challenge is the creation
of gas-sensitive materials where the response to humidity is controlled by
the material itself. Here, humidity effects are controlled through the design of
gelatin formulations in ionic liquids without and with liquid crystals as electrical
and optical sensors, respectively. In this design, the anions [DCA]− and [Cl]− of
room temperature ionic liquids from the 1-butyl-3-methylimidazolium family
tailor the response to humidity and, subsequently, sensing of VOCs in dry and
humid conditions. Due to the combined effect of the materials formulations and
sensing mechanisms, changing the anion from [DCA]− to the much more hygroscopic
[Cl]−, leads to stronger electrical responses and much weaker optical
responses to humidity. Thus, either humidity sensors or humidity-tolerant VOC
sensors that do not require sample preconditioning or signal processing to correct
humidity impact are obtained. With the wide spread of 3D- and 4D-printing
and intelligent devices, the monitoring and tuning of humidity in sustainable
biobased materials offers excellent opportunities in e-nose sensing arrays and
wearable devices compatible with operation at room conditions
Characterisation of Films Based on Exopolysaccharides from Alteromonas Strains Isolated from French Polynesia Marine Environments
Publication . Concórdio-Reis, Patrícia; Pereira, João R.; Delgado Alves, Vitor; Nabais, Ana R.; Neves, Luísa A.; Marques, Ana C.; Fortunato, Elvira; Moppert, Xavier; Guezennec, Jean; Reis, Maria A.M.; Freitas, Filomena
This work assessed the film-forming capacity of exopolysaccharides (EPS) produced by six Alteromonas strains recently isolated from different marine environments in French Polynesia atolls. The films were transparent and resulted in small colour alterations when applied over a coloured surface (ΔEab below 12.6 in the five different colours tested). Moreover, scanning electron microscopy showed that the EPS films were dense and compact, with a smooth surface. High water vapour permeabilities were observed (2.7–6.1 × 10−11 mol m−1 s−1 Pa−1), which are characteristic of hydrophilic polysaccharide films. The films were also characterised in terms of barrier properties to oxygen and carbon dioxide. Interestingly, different behaviours in terms of their mechanical properties under tensile tests were observed: three of the EPS films were ductile with high elongation at break (ε) (35.6–47.0%), low tensile strength at break (Ꞇ) (4.55–11.7 MPa) and low Young’s modulus (εm) (10–93 MPa), whereas the other three were stiffer and more resistant with a higher Ꞇ (16.6–23.6 MPa), lower ε (2.80–5.58%), and higher εm (597–1100 MPa). These properties demonstrate the potential of Alteromonas sp. EPS films to be applied in different areas such as biomedicine, pharmaceuticals, or food packaging
Deacetylation and Desuccinylation of the Fucose-Rich Polysaccharide Fucopol: Impact on Biopolymer Physical and Chemical Properties
Publication . Baptista, Sílvia; Araújo, Diana; Concórdio-Reis, Patrícia; Marques, Ana C.; Fortunato, Elvira; Delgado Alves, Vitor; Freitas, Filomena
FucoPol is an acylated polysaccharide with demonstrated valuable functional properties
that include a shear thinning fluid behaviour, a film-forming capacity, and an emulsion forming
and stabilizing capacity. In this study, the different conditions (concentration, temperature, and
time) for alkaline treatment were investigated to deacylate FucoPol. Complete deacetylation and
desuccinylation was achieved with 0.02 M NaOH, at 60 ºC for 15 min, with no significant impact on
the biopolymer’s sugar composition, pyruvate content, and molecular mass distribution. FucoPol
depyruvylation by acid hydrolysis was attempted, but it resulted in a very low polymer recovery. The
effect of the ionic strength, pH, and temperature on the deacetylated/desuccinylated polysaccharide,
d-FucoPol, was evaluated, as well as its emulsion and film-forming capacity. d-FucoPol aqueous
solutions maintained the shear thinning behaviour characteristic of FucoPol, but the apparent viscosity
decreased significantly. Moreover, contrary to FucoPol, whose solutions were not affected by the
media’s ionic strength, the d-FucoPol solutions had a significantly higher apparent viscosity for
a higher ionic strength. On the other hand, the d-FucoPol solutions were not affected by the pH
in the range of 3.6–11.5, while FucoPol had a decreased viscosity for acidic pH values and for a
pH above 10.5. Although d-FucoPol displayed an emulsification activity for olive oil similar to
that of FucoPol (98 +- 0%) for an oil-to-water ratio of 2:3, the emulsions were less viscous. The
d-FucoPol films were flexible, with a higher Young0s modulus (798 +- 152 MPa), a stress at the
break (22.5 +- 2.5 MPa), and an elongation at the break (9.3 +- 0.7%) than FucoPol (458 +- 32 MPa,
15.5 +- 0.3 MPa and 8.1 +- 1.0%, respectively). Given these findings, d-FucoPol arises as a promising
novel biopolymer, with distinctive properties that may render it useful for utilization as a suspending
or emulsifier agent, and as a barrier in coatings and packaging films
Targeting liver ischemia and reperfusion injury: nanoformulations for advanced drug/gene delivery
Publication . Ferreira-Silva, Margarida; Corvo, Maria Luísa Teixeira de Azevedo Rodrigues; Fernandes, Eduarda das Graças Rodrigues; Fernandes, Maria Alexandra Núncio de Carvalho Ramos
Hepatic ischemia and reperfusion injury (IRI) is an acute inflammatory process that may result from surgical interventions, such as liver resection or transplantation. This pathology has become a severe clinical issue, due to the increased incidence of hepatic cancer and the high number of liver transplants. So far, effective treatments have not been implemented, being crucial the development of new approaches. Drug delivery nanosystems have proved to be a major asset in therapy because of their ability to optimize drug delivery.
In this work, distinct nanosystems were proposed to tackle the disadvantages of the existent treatments: anti-inflammatory-loaded long-circulating liposomes (ibuprofen, indomethacin or quercetin) or gold nanoparticles functionalized with poly(ethylene glycol) (PEG) and antisense oligonucleotides specific for silencing human TNFA gene (AuNPs_TNF-α) associated or not with liposomes. All nanosystems were characterized in terms of their physicochemical properties and stability.
The in vitro therapeutic effect of quercetin liposomes was assessed in a hypoxia chamber model, where a decrease in pro-inflammatory biomarkers expression was observed. Using an in vivo hepatic IRI model, quercetin liposomes showed an anti-inflammatory effect and promoted hepatic lesions recovery.
The association of AuNPs_TNF-α with liposomes was successfully accomplished but distinct methodologies were required to enhance their association. The in vitro anti-inflammatory effect of free and liposomal AuNPs_TNF-α was evaluated. When inflamed cells were treated with 25 nM of ASO using liposomal AuNPs_TNF-α, no silencing effect was observed and a 11-15% reduction in cellular viability was obtained. When an ASO concentration of 240 nM was used, 4 h or 6 h incubation with free AuNPs_TNF-α resulted in a decrease in TNF-α mRNA expression of 18% and 59%, respectively, without cytotoxic effects.
In conclusion, the results suggested that quercetin liposomes and AuNPs_TNF-α might be potential therapeutic strategies to improve hepatic IRI treatment, overcoming the drawbacks presented by currently used therapies.
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Funding agency
Fundação para a Ciência e a Tecnologia
Funding programme
6817 - DCRRNI ID
Funding Award Number
UIDP/04378/2020