Charge effect on the photoinactivation of Gram-negative and Gram-positive bacteria by cationic meso-substituted porphyrins

<p>Abstract</p> <p>Background</p> <p>In recent times photodynamic antimicrobial therapy has been used to efficiently destroy Gram (+) and Gram (-) bacteria using cationic porphyrins as photosensitizers. There is an increasing interest in this approach, namely in the search of photosensitizers with adequate structural features for an efficient photoinactivation process. In this study we propose to compare the efficiency of seven cationic porphyrins differing in <it>meso</it>-substituent groups, charge number and charge distribution, on the photodynamic inactivation of a Gram (+) bacterium (<it>Enterococcus faecalis</it>) and of a Gram (-) bacterium (<it>Escherichia coli</it>). The present study complements our previous work on the search for photosensitizers that might be considered good candidates for the photoinactivation of a large spectrum of environmental microorganisms.</p> <p>Results</p> <p>Bacterial suspension (10⁷CFU mL^-1) treated with different photosensitizers concentrations (0.5, 1.0 and 5.0 μM) were exposed to white light (40 W m^-2) for a total light dose of 64.8 J cm^-2. The most effective photosensitizers against both bacterial strains were the Tri-Py⁺-Me-PF and Tri-Py⁺-Me-CO₂Me at 5.0 μM with a light fluence of 64.8 J cm^-2, leading to > 7.0 log (> 99,999%) of photoinactivation. The tetracationic porphyrin also proved to be a good photosensitizer against both bacterial strains. Both di-cationic and the monocationic porphyrins were the least effective ones.</p> <p>Conclusion</p> <p>The number of positive charges, the charge distribution in the porphyrins' structure and the <it>meso</it>-substituent groups seem to have different effects on the photoinactivation of both bacteria. As the Tri-Py⁺-Me-PF porphyrin provides the highest log reduction using lower light doses, this photosensitizer can efficiently photoinactivate a large spectrum of environmental bacteria. The complete inactivation of both bacterial strains with low light fluence (40 W m^-2) means that the photodynamic approach can be applied to wastewater treatment under natural light conditions which makes this technology cheap and feasible in terms of the light source.</p

Thermo-responsive microemulsions containing deep eutectic-based antibiotic formulations for improved treatment of resistant bacterial ocular infections

The rise of antibiotic resistant strains, as methicillin-resistant Staphylococcus aureus (MRSA), challenges the current treatment of infections. In the case of ocular infections, antibiotic eye drops are commonly prescribed. However, their efficacy is usually compromised by the low viscosity of these formulations and the eye drainage. To overcome these drawbacks, deep eutectic solvent (DES)-based microemulsions with thermo-responsive character, that increase their viscosity upon contact with the eye have been developed. Using betaine-based DES aqueous solutions, it is possible to increase up to 140-fold the water solubility of the antibiotic chloramphenicol, typically used in ocular infections. The DES solutions containing the antibiotic are applied as water phases in water-in-oil-in-water (w/o/w) microemulsions, being stable up to 3 months. Furthermore, a sustained-release and a higher permeation of the antibiotic through the cornea than that of commercialized eye drops is achieved, while presenting comparable cytotoxicity profiles (cell viabilities > 88%). Higher antimicrobial activity and faster action of the antibiotic in case of infection with MRSA is observed compared to the commercialized formulations (7 log10 of inactivation in 48 h vs 72 h). Overall, these microemulsions comprising DES are a promising strategy to achieve higher antibiotic effectiveness in the treatment of resistant bacterial infections.info:eu-repo/semantics/publishedVersio

Isomerisation of pinene oxide in the presence of an indenyl Molybdenum carbonyl complex

Trabalho apresentado 18th IUPAC International Symposium on Organometallic Chemistry Directed Towards Organic Synthesis, 28 june - 2 july 2015, Barcelona, Spaininfo:eu-repo/semantics/publishedVersio

Results after two years of follow-up with an adult team

Funding: This article was supported by National Funds through FCT-Fundação para a Ciência e a Tecnologia, I.P., within CINTESIS, R&D Unit (reference UIDB/4255/2020).We aimed to report the implementation of a phenylketonuria (PKU) transition program and study the effects of follow-up with an adult team on metabolic control, adherence, and loss of follow-up. Fifty-five PKU patients were analysed in the study periods (SP): 2 years before (SP1) and after the beginning of adult care (SP2). Retrospective data on metabolic control and number of clinic appointments were collected for each SP, and protein intakes were analysed. In SP2, three patients (6%) were lost to follow-up. There was a small but statistically significant increase in median number of annual blood spots from SP1 to SP2: 11 (7–15) vs. 14 (7–20); p = 0.002. Mean ± SD of median blood Phe remained stable (525 ± 248 µmol/L vs. 552 ± 225 µmol/L; p = 0.100); median % of blood Phe < 480 µmol/L decreased (51 (4–96)% vs. 37 (5–85)%; p = 0.041) and median number of clinic appointments increased from SP1 to SP2: (5 (4–6) vs. 11 (8–13); p < 0.001). No significant differences were found regarding any parameter of protein intake. Our results suggest that the implementation of an adult service was successful as impact on metabolic control was limited and attendance remained high. Continuous dietetic care likely contributed to these results by keeping patients in fol-low-up and committed to treatment.publishersversionpublishe

Desemprego: experiências de transição

Work appears as an important determinant in psychological health and well-being (Blustein, 2008). However, the current structure of the labor market is complex, unpredictable and unstable, making it necessary to rethink the meaning of work in human existence. This article focuses on the different types of transitions (voluntary vs. involuntary) as well on the different reactions to unemployment, and presents some intervention strategies in the context of career counseling, conceived as a (possible) response to changes in employment.Le travail apparaît comme un déterminant de la santé psychologique et du bien-être (Blustein, 2008). Cependant, la structure actuelle du marché du travail est complexe, imprévisible et instable, ce qui rend nécessaire de repenser la signification du travail dans l’existence humaine. Cet article se concentre en la première partie sur les différents types de transition (volontaire ou involontaire), et la diversité des modes de réaction au chômage, et la seconde partie présente quelques stratégies d’intervention dans le contexte de l’orientation professionnelle, conçue comme une réponse (possible) à des changements dans l’emploi.O trabalho afigura-se como determinante para a saúde psicológica e o bem-estar (Blustein, 2008). Contudo, a actual estrutura do mercado de trabalho é complexa, imprevisível e instável, sendo necessário repensar o significado do trabalho na existência humana. O presente artigo incide, na primeira parte sobre os diferentes tipos de transição (voluntária vs. involuntária), e a diversidade de modos de reacção face ao desemprego, e na segunda parte, são apresentadas algumas estratégias de intervenção, no âmbito do aconselhamento de carreira, concebidas como uma (possível) resposta às mudanças que ocorrem ao nível do emprego

The concept of anorexia of aging in late life depression:A cross-sectional analysis of a cohort study.

INTRODUCTION: Anorexia of aging (AA) is classically associated with depression. However, robust evidence is lacking regarding general clinic populations. Our aim was to evaluate the association between AA and major depressive disorder (MDD) in geriatric outpatients from a middle-income country. METHODS: We conducted a cross-sectional analysis of a cohort study. MDD diagnosis was assessed with a psychiatric interview (SCID-5-CV) according to DSM-5 criteria. Depressive symptomatology was assessed by a 15-items Geriatric Depression Scale (GDS) and the PHQ-9 questionnaire. Appetite was measured with the Simple Nutrition Appetite Questionnaire (SNAQ), whereas AA was defined as a SNAQ score ≤13 points). Linear and logistic regression analysis adjusted for potential confounders were applied to assess the association between depressive symptomatology, MDD and AA. RESULTS: Of the total 339 participants, MDD was present in 65. AA was more frequent in patients with MDD compared to non-depressed patients (30.7 versus 7.7%; p<0.001). The SNAQ score was lower in depressed patients (14.5 vs. 16.6, p<0.001). Adjusted for confounding, linear and logistic regression showed a significant association between the GDS score, PHQ-9 score and MDD with the SNAQ score (p<0.001) and cut-off representing AA (p<0.001), respectively. Moreover, MDD and AA interacted significantly with their association with weight loss (p<0.001). CONCLUSIONS: Depression scales (even without somatic complaints) and MDD were associated with AA in geriatric outpatients. AA is associated with weight loss in MDD. Prospective studies should expand these findings

Evaluation of the Antimicrobial Activity of the Decoction of Tropidurus hispidus (Spix, 1825) and Tropidurus semitaeniatus (Spix, 1825) Used by the Traditional Medicine

Tropidurus hispidus and Tropidurus semitaeniatus are two lizard species utilized in traditional medicine in Northeast Brazil. Their medicinal use includes diseases related with bacterial infections such as tonsillitis and pharyngitis. They are used in the form of teas (decoctions) for the treatment of illnesses. In this work, we evaluated the antimicrobial activity of the decoctions of T. hispidus (DTH) and T. semitaeniatus (DTS) against bacterial strains, namely, standard and multiresistant Escherichia coli, Staphylococus aureus, and Pseudomonas aureuginosa, alone and in combination with aminoglycoside antibiotics. The decoctions were prepared using the whole body of the dried lizards, and the filtrate was frozen and lyophilized. When tested alone, the samples did not demonstrate any substantial inhibition of bacterial growth. However, in combination with antibiotics as aminoglycosides, decoctions reduced the minimal inhibitory concentration (MIC) of the assayed antibiotics against multiresistant strains of S. aureus and P. aureuginosa. Chemical prospecting tests revealed the presence of alkaloids in DTS. This is the first study evaluating the medicinal efficacy of T. hispidus and T. semitaeniatus and contributes to the list of new sources of medicines from natural products of animal origin

Antimicrobial Photodynamic Therapy: Study of Bacterial Recovery Viability and Potential Development of Resistance after Treatment

Antimicrobial photodynamic therapy (aPDT) has emerged in the clinical field as a potential alternative to antibiotics to treat microbial infections. No cases of microbial viability recovery or any resistance mechanisms against it are yet known. 5,10,15-tris(1-Methylpyridinium-4-yl)-20-(pentafluorophenyl)-porphyrin triiodide (Tri-Py+-Me-PF) was used as photosensitizer. Vibrio fischeri and recombinant Escherichia coli were the studied bacteria. To determine the bacterial recovery after treatment, Tri-Py+-Me-PF (5.0 μM) was added to bacterial suspensions and the samples were irradiated with white light (40 W m−2) for 270 minutes. Then, the samples were protected from light, aliquots collected at different intervals and the bioluminescence measured. To assess the development of resistance after treatment, bacterial suspensions were exposed to white light (25 minutes), in presence of 5.0 μM of Tri-Py+-Me-PF (99.99% of inactivation) and plated. After the first irradiation period, surviving colonies were collected from the plate and resuspended in PBS. Then, an identical protocol was used and repeated ten times for each bacterium. The results suggest that aPDT using Tri-Py+-Me-PF represents a promising approach to efficiently destroy bacteria since after a single treatment these microorganisms do not recover their viability and after ten generations of partially photosensitized cells neither of the bacteria develop resistance to the photodynamic process

Melhoramento do sobreiro para uma regeneração artificial sustentável

O sobreiro (Quercus suber) é uma espécie singular devido à sua importância no funcionamento do ecossistema mediterrânico e na produção de cortiça. No entanto, apesar da sua importância ecológica e sócio-económica, pouco se compreende ainda dos seus processos de adaptabilidade às diferentes condições ambientais. Em algumas áreas do mediterrâneo ocidental, as florestas de sobreiro encontram-se em declínio e a manutenção destes ecossistemas requer a compreensão do seu funcionamento (e.g. regeneração, crescimento e interações entre hospedeiro e pragas/doenças). Para além de uma crescente redução da área de floresta, o sobreiro apresenta geralmente uma reduzida regeneração natural. Nos últimos anos, largas áreas de sobreiro foram reflorestadas no entanto, a regeneração artificial, quer por sementeira quer por plantação, obteve resultados variáveis com baixas taxas de sobrevivência. Apesar da necessidade de melhorar o manuseamento das sementes e das técnicas de produção e plantação ser geralmente reconhecida pelos proprietários florestais, a utilização de material genético adequado é quase sempre ignorada. De forma a dar resposta a alguns destes problemas está em curso o projeto PTDC/AGR-AAM/104364/2008: Melhoramento do sobreiro para uma regeneração artificial sustentável, que tem como principal objetivo melhorar a qualidade genética e fisiológica do material reprodutivo de sobreiro usado nas arborizações, focando-se em três aspetos essenciais: adaptabilidade da espécie, armazenamento da semente a longo prazo e produção de semente. Este é um trabalho multidisciplinar onde se integram os resultados de várias perspetivas – ecofisiológica, genética quantitativa e biologia molecular – de forma a compreender as suas interações e avaliar a plasticidade fenotípica, particularmente em condições de secura, contribuindo para ajustar os limites das regiões de proveniência e definir zonas de transferência de sementes