1,545 research outputs found
Antibacterial activity of phenyl isothiocyanate on Escherichia coli and Staphylococcus aureus
The present study has been aimed to assess the antibacterial effects of the glucosinolate hydrolysis product phenyl isothiocyanate (PITC) against Escherichia coli and Staphylococcus aureus. Aspects on the antibacterial mode of action of PITC have also been characterized, such as the changes on surface physicochemical characteristics and membrane damage. The minimum inhibitory concentration of PITC was 1000 ”g/mL, for both bacteria. The antimicrobial potential of PITC was compared with selected antibiotics (ciprofloxacin, erythromycin, streptomycin, tetracycline and spectinomycin),that reported a moderate effect. The combination of PITC with ciprofloxacin and erythromycin against S.aureus exhibited a good antimicrobial efficacy, due to an additive effect (the diameter of inhibition zones increased from 30 to 40 mm for ciprofloxacin and almost the double for erythromycin). The other combinations reported unsatisfactory results against both bacteria. The study of the physiological changes induced by PITC action demonstrated the interaction
between the electrophilic compound and the bacterial cells at several points that causes changes in membrane properties (decreases negative surface charge, increases surface hydrophilicity and electron donor characteristics). PITC was also found to disturb membrane function, as manifested by phenomena such as cellular disruption and loss of membrane integrity, triggering cell death.This work was supported by Operational Programme for Competitiveness Factors - COMPETE and by FCT - Portuguese Foundation for Science and Technology through Projects Bioresist - PTDC/EBB-EBI/105085/2008; Phytodisinfectants - PTDC/DTP-SAP/1078/2012; the PhD grant (SFRH/BD/63398/2009-Anabela Borges) and the Post-Doctoral grant (SFRH/BPD/81982/2011-Lucia C. Simoes)
Activity of allylisothiocyanate and 2-phenylethylisothiocyanate on motility and biofilm prevention of pathogenic bacteria
Isothiocyanates (ITCs) are plant secondary metabolites with a range of biological effects including antimicrobial
activity. This study reports the activity of two ITCs [allylisothiocyanate (AITC) and 2-phenylethylisothiocyanate
(PEITC)] on bacterial motility and prevention of biofilm formation by Escherichia coli, Pseudomonas
aeruginosa, Staphylococcus aureus and Listeria monocytogenes. AITC caused total inhibition of swimming (P.
aeruginosa) and swarming (E. coli, P. aeruginosa) motilities. PEITC caused total inhibition of swimming (E. coli,
P. aeruginosa and L. monocytogenes) and swarming (E. coli and P. aeruginosa) motilities. Colony spreading of S.
aureus was completely inhibited with PEITC. Total biofilm prevention was observed for E. coli with AITC. AITC
and PEITC had no preventive effects in biofilm formation by S. aureus and L. monocytogenes, respectively.
Significant preventive action with AITC on biofilm formation by P. aeruginosa (90%) and by L. monocytogenes
(61%), and with PEITC on biofilm formation by S. aureus (75%) was verified. In terms of viability, AITC and
PEITC promoted reductions higher than 87% for all the biofilms tested. In conclusion, these molecules
demonstrated potential to inhibit bacterial motility and to prevent biofilm formation of pathogenic bacteria
Is there a causal role for homocysteine concentration in blood pressure?:A Mendelian randomization study
Background: An understanding of whether homocysteine is a cause or a marker of increased blood pressure is relevant because blood homocysteine can be effectively lowered by safe and inexpensive interventions (e.g., vitamin B-6, B-9, and B-12 supplementation). Objective: The aim was to assess the causal influence of homocysteine on systolic and diastolic blood pressure (SBP and DBP, respectively) in adults with the use of Mendelian randomization (MR). Design: Data from the 1982 Pelotas Birth Cohort (Brazil) were used. A total of 4297 subjects were evaluated in 2004â2005 (mean age: 22.8 y). The association of homocysteine concentration with SBP and DBP was assessed by conventional ordinary least-squares (OLS) linear regression and 2-stage least-squares (2SLS) regression (MR analysis). The single nucleotide polymorphism (SNP) methylenetetrahydrofolate reductase (MTHFR) C677T (rs1801133) was used as proxy for homocysteine concentration. We also applied MR to data from the International Consortium for Blood Pressure (ICBP) genomewide association studies (>69,000 participants) using rs1801133 and additional homocysteine-associated SNPs as instruments. Results: In OLS regression, a 1-SD unit increase in log homocysteine concentration was associated with an increase of 0.9 (95% CI: 0.4, 1.4) mm Hg in SBP and of 1.0 (95% CI: 0.6, 1.4) mm Hg in DBP. In 2SLS regression, for the same increase in homocysteine, the coefficients were â1.8 mm Hg for SBP (95% CI: â3.9, 0.4 mm Hg; P = 0.01) and 0.1 mm Hg for DBP (95% CI: â1.5, 1.7 mm Hg; P = 0.24). In the MR analysis of ICBP data, homocysteine concentration was not associated with SBP (ÎČ = 0.6 mm Hg for each 1-SD unit increase in log homocysteine; 95% CI: â0.8, 1.9 mm Hg) but was positively associated with DBP (ÎČ = 1.1 mm Hg; 95% CI: 0.2, 1.9 mm Hg). The association of genetically increased homocysteine with DBP was not consistent across different SNPs. Conclusion: Overall, the present findings do not corroborate the hypothesis that homocysteine has a causal role in blood pressure, especially in SBP
TIRA: An OpenAPI Extension and Toolbox for GDPR Transparency in RESTful Architectures
Transparency - the provision of information about what personal data is
collected for which purposes, how long it is stored, or to which parties it is
transferred - is one of the core privacy principles underlying regulations such
as the GDPR. Technical approaches for implementing transparency in practice
are, however, only rarely considered. In this paper, we present a novel
approach for doing so in current, RESTful application architectures and in line
with prevailing agile and DevOps-driven practices. For this purpose, we
introduce 1) a transparency-focused extension of OpenAPI specifications that
allows individual service descriptions to be enriched with transparency-related
annotations in a bottom-up fashion and 2) a set of higher-order tools for
aggregating respective information across multiple, interdependent services and
for coherently integrating our approach into automated CI/CD-pipelines.
Together, these building blocks pave the way for providing transparency
information that is more specific and at the same time better reflects the
actual implementation givens within complex service architectures than current,
overly broad privacy statements.Comment: Accepted for publication at the 2021 International Workshop on
Privacy Engineering (IWPE'21). This is a preprint manuscript (authors' own
version before final copy-editing
Biofilms in diabetic foot ulcers: impact, risk factors and control strategies
Diabetic foot ulcers (DFUs) are a serious complication from diabetes mellitus, with a huge economic, social and psychological impact on the patients life. One of the main reasons why DFUs are so difficult to heal is related to the presence of biofilms. Biofilms promote wound inflammation and a remarkable lack of response to host defences/treatment options, which can lead to disease progression and chronicity. In fact, appropriate treatment for the elimination of these microbial communities can prevent the disease evolution and, in some cases, even avoid more serious outcomes, such as amputation or death. However, the detection of biofilm-associated DFUs is difficult due to the lack of methods for diagnostics in clinical settings. In this review, the current knowledge on the involvement of biofilms in DFUs is discussed, as well as how the surrounding environment influences biofilm formation and regulation, along with its clinical implications. A special focus is also given to biofilm-associated DFU diagnosis and therapeutic strategies. An overview on promising alternative therapeutics is provided and an algorithm considering biofilm detection and treatment is proposed.This work was supported by: Base FundingâUIDB/00511/2020 of the Laboratory for
Process Engineering, Environment, Biotechnology and EnergyâLEPABEâfunded by national
funds through the FCT/MCTES (PIDDAC); Project Biocide_for_Biofilm-PTDC/BII-BTI/30219/2017-
POCI-01-0145-FEDER-030219, ABFISHâPTDC/ASP-PES/28397/2017-POCI-01-0145-FEDER- 028397
and Germirrad-POCI-01-0247-FEDER-072237, funded by FEDER funds through COMPETE2020â
Programa Operacional Competitividade e Internacionalização (POCI) and by national funds (PID DAC) through FCT/MCTES. The authors also thank the CITAB (Centre for the Research and Technol ogy of Agro-Environmental and Biological Sciences) under the scope of the FCT funds with reference
UIDB/AGR/04033/2020. Ana Afonso (2020.04773.BD) and Diana Oliveira (SFRH/BD/138217/2018)
acknowledge the FCT grants. Anabela Borges thanks the FCT for the financial support of their work
contract through the Scientific Employment StimulusâIndividual Callâ[CEECIND/01261/2017].info:eu-repo/semantics/publishedVersio
Using Mendelian Randomisation to Prioritise Candidate Maternal Metabolic Traits Influencing Offspring Birthweight
Marked physiological changes in pregnancy are essential to support foetal growth; however, evidence on the role of specific maternal metabolic traits from human studies is limited. We integrated Mendelian randomisation (MR) and metabolomics data to probe the effect of 46 maternal metabolic traits on offspring birthweight (N = 210,267). We implemented univariable two-sample MR (UVMR) to identify candidate metabolic traits affecting offspring birthweight. We then applied two-sample multivariable MR (MVMR) to jointly estimate the potential direct causal effect for each candidate maternal metabolic trait. In the main analyses, UVMR indicated that higher maternal glucose was related to higher offspring birthweight (0.328 SD difference in mean birthweight per 1 SD difference in glucose (95% CI: 0.104, 0.414)), as were maternal glutamine (0.089 (95% CI: 0.033, 0.144)) and alanine (0.137 (95% CI: 0.036, 0.239)). In additional analyses, UVMR estimates were broadly consistent when selecting instruments from an independent data source, albeit imprecise for glutamine and alanine, and were attenuated for alanine when using other UVMR methods. MVMR results supported independent effects of these metabolites, with effect estimates consistent with those seen with the UVMR results. Among the remaining 43 metabolic traits, UVMR estimates indicated a null effect for most lipid-related traits and a high degree of uncertainty for other amino acids and ketone bodies. Our findings suggest that maternal gestational glucose and glutamine are causally related to offspring birthweight
Attractiveness of host plant volatile extracts to the Asian citrus psyllid, diaphorina citri, is reduced by terpenoids from the non-host cashew
Diaphorina citri is a vector of the bacterial causative agent of Huanglongbing (HLBâ=âCitrus greening), a severe disease affecting citrus crops. As there is no known control for HLB, manipulating insect behaviour through deployment of semiochemicals offers a promising opportunity for protecting citrus crops. The behavioural responses of D. citri to plant volatiles, and the identity of these plant volatiles were investigated. Volatiles were collected from host plants Murraya paniculata, Citrus sinensis, C. reshni, C. limettioides, Poncirus trifoliata, and from non-host plants Psidium guajava, Mangifera indica, Anacardium occidentale. In behavioural assays, female D. citri spent more time in the arms containing volatiles from either M. paniculata or C. sinensis compared to the control arms. When D. citri was exposed to volatiles collected from A. occidentale, they preferred the control arm. Volatiles emitted from the other studied plants did not influence the foraging behaviour of D. citri. Chemical analyses of volatile extracts from C. sinensis, M. paniculata, and A. occidentale revealed the presence of the terpenoids (E)-4,8-dimethylnona-1,3,7âtriene (DMNT) and (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT) in higher amounts in A. occidentale. In further behavioural bioassays, female D. citri spent less time in arms containing a synthetic blend of DMNT and TMTT compared to the control arms. Female D. citri also spent less time in arms containing the synthetic blend in combination with volatile extracts from either M. paniculata or C. sinensis compared to the control arms. Results suggest that higher release of the two terpenoids by A. occidentale make this species unattractive to D. citri, and that the terpenoids could be used in reducing colonisation of citrus plants and therefore HLB infection
A Review
This work is co-financed by FEDER, European Funds, through the COMPETE 2020 POCI and PORL, National Funds through FCTâPortuguese Foundation for Science and Technology, and POR Lisboa2020, under the projects PIDDAC (POCI-01-0145-FEDER-007688, Reference UIDB/50025/2020-2023) and PTDC/CTMCTM/30623/2017 (DREaMM). P.S. also acknowledges the individual contract CEECIND.03189.2020. C.T. acknowledges i3N for the Ph.D. grant with reference UI/BD/151541/2021.
Publisher Copyright:
© 2022 by the authors.In recent decades, new and improved materials have been developed with a significant interest in three-dimensional (3D) scaffolds that can cope with the diverse needs of the expanding biomedical field and promote the required biological response in multiple applications. Due to their biocompatibility, ability to encapsulate and deliver drugs, and capacity to mimic the extracellular matrix (ECM), typical hydrogels have been extensively investigated in the biomedical and biotechnological fields. The major limitations of hydrogels include poor mechanical integrity and limited cell interaction, restricting their broad applicability. To overcome these limitations, an emerging approach, aimed at the generation of hybrid materials with synergistic effects, is focused on incorporating nanoparticles (NPs) within polymeric gels to achieve nanocomposites with tailored functionality and improved properties. This review focuses on the unique contributions of clay nanoparticles, regarding the recent developments of clay-based nanocomposite hydrogels, with an emphasis on biomedical applications.publishersversionpublishe
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