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Objectives: To study the implementation of environmental sustainability practices at Portuguese dental clinics, the importance given by clinical directors to these practices, and the barriers felt in their applicability. Methods: This cross-sectional study’s target population was clinical directors (Dentists or Stomatologists) working in Portugal. Data was collected through an online questionnaire shared in several groups of clinicians on social networks, published in digital journals, and sent by email through medical associations. It was available between February and April 2021. The questionnaire collected information about the implementation of environmental sustainability practices in dental clinics within six categories of management: devices and equipment, dental amalgam, imaging, paper, energy, and water. There were also questions about the importance of these practices and the barriers felt. Descriptive statistics of all variables were performed. Results: The sample included 245 clinical directors, of which 65.5% were female and 43.7% were between 40 and 49 years old. There was a high degree of implementation of environmental sustainability practices related to imaging (82.6%), dental amalgam (80.7%), water (67.5%), energy (67.4%), paper (63.4%), and devices and equipment (62.9%). Almost all respondents (96%) considered that environmental sustainability practices are important or very important, and the more frequently referred barriers to implementation were costs (44.6%) and lack of training/information (16.3%). Conclusions: Clinical directors showed good environmental awareness and satisfactory implementation of environmental sustainability practices in dental clinics. Costs were the most reported barrier to the implementation of further practices.

Objetivos: Os objetivos deste estudo foram caracterizar a implementação da escovagem e de outras medidas de promoção da saúde oral em jardins de infância e identificar os fatores que influenciam a implementação da escovagem dos dentes. Métodos: A recolha de dados foi efetuada através de um questionário online dirigido aos educadores de infância a lecionar em Portugal. O questionário incluiu a caracterização do jardim de infância, do educador, da escovagem dos dentes e de outras medidas. Foi realizada a estatística descritiva e inferencial, utilizando o teste não-paramétrico do qui-quadrado (α=0,05). Resultados: A amostra incluiu 1618 educadores de infância, com uma média de 47,1 anos (dp=9,975). A escovagem diária era realizada em 40,6% dos jardins de infância. As principais razões apontadas para a não escovagem foram o risco de transmissão de doenças e limitações de recursos humanos e de espaço. Uma percentagem considerável de jardins de infância (43,8%) nunca foi visitada pelas equipas de saúde oral. Nos jardins de infância onde os educadores exercem há mais anos (p=0,004), onde os educadores tiveram formação sobre saúde oral (p

Objetivos: Estudar a literacia em saúde dos estudantes do 3.º ano da Faculdade de Medicina Dentária da Universidade de Lisboa e relacioná-la com os seus dados demográficos, comportamentos, autoperceção e estado de saúde oral. Métodos: Foi realizado um estudo observacional, analítico e transversal. A recolha dos dados incluiu um questionário, uma observação intraoral e uma entrevista. O questionário recolheu informação sobre os dados demográficos e comportamentos dos estudantes. Na entrevista foi aplicada a versão portuguesa do instrumento Newest Sign Vital (NSV-Pt) para o estudo da literacia em saúde. A observação intraoral incluiu o diagnóstico de cárie segundo os critérios do Internacional Caries Detection and Assessment System (ICDAS II). A análise estatística incluiu a estatística descritiva e foram utilizados os testes de qui-quadrado, Mann Whitney e Kruskal Wallis com um nível de significância de 5%. Resultados: A amostra foi constituída por 92 estudantes. A média de respostas corretas ao NSV-Pt foi 4,87 (dp=1,15). Nenhum estudante teve elevada probabilidade de literacia em saúde limitada e 87,6% dos estudantes revelaram ter uma literacia em saúde adequada. Verificou-se uma associação estatisticamente significativa entre a literacia em saúde e a frequência de visita à consulta de saúde oral (p=0,04). Conclusões: A maioria dos estudantes apresentaram uma literacia em Saúde adequada. Os estudantes que frequentaram mais frequentemente o profissional de saúde oral apresentaram piores níveis de literacia em saúde.

Background The Oral Health-related Quality of Life (OHRQoL) is an essential part of health and wellbeing that aims to assess the impact of oral health on aspects of personal and social life. This investigation aimed to study the OHRQoL in undergraduate students and relate it to sociodemographic, academic behaviours, oral health behaviours, the presence of oral problems and self-perception of oral health. Material and Methods The study target-population consisted of the undergraduate students attending the University of Lisbon (UL). Data collection was carried out through an online questionnaire which included self-reported sociodemographic and academic characteristics, behaviours and oral health status, and the Oral Health Impact Profile-14 (OHIP-14). Descriptive statistics were performed, and the Mann-Whitney and Kruskal-Wallis tests were used (α=0.05). Results The sample included 933 students, aged between 18 and 48 years old (mean=21.22 / SD=3.11). The global mean value of OHIP-14 was 5.98 (SD=6.71) and 89.8% of the students presented OHIP-14 values between 0 and 14. Psychological discomfort and physical pain were the dimensions of OHIP-14 with the greatest impact on OHRQoL. Most of the students brushed their teeth twice a day (79.7%) with fluoridated toothpaste (90.8%) and perceived their oral health as “good” (56.3%). Several aspects were significantly related (p

Objetivos: Conhecer as atitudes e comportamentos de saúde oral dos estudantes finalistas do curso de Medicina Dentária, estudar o seu estado e autoperceção da saúde oral e relacionar as atitudes e comportamentos com o estado de saúde oral. Métodos: A população-alvo foi constituída pelos estudantes do 5.º ano do curso de Mestrado Integrado em Medicina Dentária da Faculdade de Medicina Dentária da Universidade de Lisboa. Os dados foram recolhidos por um questionário sobre as atitudes e comportamentos de saúde oral, incluindo o Hiroshima University Dental Behavioural Inventory (HUDBI), e por um exame intraoral para o estudo de cárie (segundo critérios ICCMS), do nível de higiene oral (ID-S) e da hemorragia gengival (IPC modificado). Foi realizada a estatística descritiva e utilizados os testes Mann-Whitney, Kruskal-Wallis e correlação de Spearman (α=0,05). Resultados: O valor médio de HUDBI foi 9,20 (DP=1,34). Quase todos os estudantes (97,8%) escovavam os dentes bidiariamente, mas apenas 23,9% utilizavam o fio dentário diariamente. A prevalência de cárie foi 97,8%, sendo o CA-6POD médio 9,5 (dp=4,3). O nível de higiene oral foi excelente em 43,5% dos estudantes. A frequência de hemorragia gengival foi de 97,7%, sendo o IPC modificado médio 0,29 (dp=0,2). Verificou-se uma associação positiva entre o consumo de alimentos açucarados e o C3-6POD (p=0,05) e entre a autoperceção da saúde oral e o C3-6POD (p=0,04). Conclusões: Os estudantes apresentaram atitudes e comportamentos positivos e bons indicadores de higiene oral e hemorragia gengival, contudo, a prevalência de cárie foi elevada.

Currently, there is increasing interest in assessing the potential of bacterial laccases for industrial and environmental applications especially in harsh conditions. The environmental impact of the textile industry requires novel and effective technologies to mitigate the presence of dyes in wastewaters before discharging into the environment. Dyes usually remain stable in the presence of a variety of chemicals, light and are recalcitrant to microbial degradation. Among available technologies the biological treatments offer environmentally friendly strategies for decolorizing and detoxifying these compounds. The recent discovery of versatile laccases in streptomycetes opens up new opportunities for their commercial application. The aim of this study is to assess the potential of a novel bacterial laccase SilA produced by Streptomyces ipomoeae CECT 3341 active over wide temperature and pH ranges for use as an eco-friendly, biological treatment for the degradation of textile dyes. Insights into the enhancement of the oxidative action of this enzyme through the use of natural redox mediators are presented together with an assessment of the potential toxicity of the degradation products. Our results confirm that the combination of the laccase and natural mediators such as acetosyringone and methyl syringate enhanced the decolorization and detoxification of a variety of textile dyes up to sixfold and 20-fold, respectively. Mediator concentration was found to have a significant effect (p 55 °C) and salinity and neutral pH, conditions which are unfavourable for conventional fungal laccases. Keywords: Laccase, Dyes decolorization, Streptomyces, Natural mediators, Detoxification

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Underwater noise pollution from impulsive sources (e.g. explosions, seismic airguns, percussive pile driving) can affect marine fauna through mortality, physical injury, auditory damage, physiological stress, acoustic masking, and behavioural responses. Given the potential for large-scale impact on marine ecosystems, some countries are now monitoring impulsive noise activity, coordinated internationally through Regional Seas Conventions. Here, we assess impulsive noise activity in the Northeast Atlantic reported during 2015–2017 to the first international impulsive noise register (INR), established in 2016 under the OSPAR Convention. Seismic airgun surveys were the dominant noise source (38%–56% of annual activity) and declined by 23% during 2015–2017. Reported pile driving activity increased 72%. Explosions and sonar/acoustic deterrent devices both had year-on-year increases in reported activity. Some increases were attributable to more comprehensive reporting in later years. We discuss utilising the INR for risk assessment, target setting, and forward planning, and the implementation of similar systems in other regions.

Chitosan-genipin films present a bluish-green color due to the conjugated double bonds formed when monomeric or dimeric genipin residues bridge chitosan. This phenomenon limits their use when colorless materials are required. In this work, a two-step oxidation strategy was developed aiming to remove color from chitosan-genipin films while preserving their functional properties. A combined system using the recombinant CotA laccase from Bacillus subtilis mediated by 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) followed by a H 2 O 2 oxidation step was settled. ABTS boosted the laccase performance resulting in light brown chitosan-genipin films that were further decolorized upon immersion in a 5% H 2 O 2 solution at pH 11.0 and 40 °C for 30 min. The applied methodology leads to films that sustain both acidic stability and antioxidant capacity of the pristine films. Overall, the combined CotA laccase-ABTS/hydrogen peroxide developed methodology efficiently produce active and decolorized chitosan-genipin films with potential for application as eco-friendly transparent material which may have application as food packaging.

ResumoObjetivosa) Estudar as atitudes, comportamentos e estado de saúde oral dos alunos do 1.° ano da Faculdade de Medicina Dentária da Universidade de Lisboa (FMDUL); b) relacionar as atitudes e comportamentos com o estado de saúde oral; c) relacionar as atitudes, comportamentos e estado de saúde oral com o nível de instrução da mãe e com a nota de ingresso no ensino superior; d) verificar a existência de diferenças entre os 3 cursos da FMDUL, relativamente aos indicadores estudados.MetodosA amostra foi constituída por 116 alunos, sendo a recolha de dados realizada por questionário e por uma observação intraoral. Foram utilizados os critérios do International Caries Detection and Assessment System II, do índice de higiene oral simplificado e do índice periodontal comunitário modificado. A análise estatística foi realizada com testes não paramétricos (α=0,05).ResultadosA prevalência de cárie foi de 96,6% e o CA‐6POD médio de 6,4 (dp=3,7). A maioria dos indivíduos apresentava uma higiene oral razoável (65,5%) e hemorragia gengival (98,3%). Verificou‐se a existência de uma correlação negativa entre a nota de ingresso e o CPOD (ρ=–0,212, p=0,023). Apenas se verificaram diferenças entre os cursos relativamente à prevalência de cárie e à média de CPOD.ConclusõesAs atitudes e os comportamentos em higiene oral podem ser considerados positivos, no entanto, a prevalência de cárie foi elevada. O nível de higiene oral foi razoável, apesar da prevalência de hemorragia gengival ser alta. Os alunos com nota de ingresso mais elevada apresentaram menor gravidade de cárie. Os alunos de Medicina Dentária apresentaram menor prevalência e gravidade de cárie do que os alunos de Prótese Dentária.AbstractObjectivesa) To study attitudes, behaviors and oral health status of 1st year students from FMDUL; b) relate the attitudes and behaviors with oral health status; c) list the attitudes, behavior and oral health status with the mother's education level and the admission grades; d) study differences between the three FMDUL courses.MethodsThe sample consisted of 116 students. Data collection was conducted through a questionnaire and oral examination. Diagnosys criteria included the International Caries Detection and Assessment System II, the Simplified Oral Hygiene Index modified Community Periodontal Index. Statistical analysis was performed using nonparametric tests (α=0.05).ResultsCaries prevalence was 96.6% and DMFT average 6.4 (SD=3.7). The majority of subjects had a reasonable oral hygiene (65.5%) and gingival bleeding (98.3%). It was found a negative correlation between the admission grade and the DMFT (ρ=–0.212, p=0.023). There were found differences between courses regarding the caries prevalence (p=0.049) and the mean DMFT.ConclusionsAttitudes and behaviors in oral hygiene can be considered positive. The prevalence of caries was high, but the level of oral hygiene was reasonable and prevalence of gingival bleeding was high. Students with higher admission grades had lower severity of dental caries. Students of Dental Medicine showed less caries prevalence than students of Dental Prothesis.

ResumoObjetivosDeterminar nas crianças de 6 anos da Freguesia de Mafra a prevalência e gravidade de cárie na dentição decídua e o nível de higiene oral. Descrever os comportamentos relacionados com a saúde oral e analisar a associação entre a cárie, o nível de higiene oral e estes comportamentos.MétodosEstudo observacional e transversal. Foi recolhida informação sobre comportamentos relacionados com a saúde oral através de um questionário. Os dados relativos à cárie (Índice cpod) e ao nível de higiene oral (IHO‐S) foram obtidos por um observador calibrado que utilizou os critérios da OMS. A análise dos dados foi efetuada com os testes do qui‐quadrado, Mann‐Whitney e Kruskal‐Wallis (α=0,05).ResultadosA amostra consistiu em 165 crianças. A prevalência de cárie na dentição decídua foi de 32,7% e o cpod de 1,32, encontrando‐se a grande maioria dos dentes cariados (84,9%). A média do IHO‐S foi 1,74. A maioria das crianças já havia visitado o dentista (61,0%) e ingeria alimentos cariogénicos «às vezes» (76,2%). Mais de 80% das crianças escovava os dentes diariamente com a ajuda dos pais e 66,7% iniciou a escovagem entre o primeiro e o terceiro ano de vida. Verificou‐se uma associação positiva entre a cárie e as visitas ao dentista e a idade de início de escovagem dos dentes.ConclusõesA prevalência e gravidade de cárie podem ser consideradas baixas, no entanto, a maioria dos dentes com experiência de cárie não estavam tratados. As atividades de promoção da saúde oral devem incluir informação sobre os comportamentos alimentares e, em especial, informação e motivação para o início precoce da escovagem dos dentes.AbstractObjectivesDetermine the prevalence and severity of dental caries in the primary dentition and the oral hygiene level in 6‐year‐old children of Mafra. Describe oral health related behaviours and analyze the association between oral health behaviours and both caries in the primary dentition and oral hygiene level.MethodsCross‐sectional study. Oral health behaviours information was obtained by a questionnaire. Caries (cpod using WHO criteria) and oral hygiene (OHI‐S) data was collected by a calibrated observer. Statistical analysis was performed using Chi‐Square, Mann‐Whitney and Kruskal‐Wallis tests (α=0.05).ResultsThe sample included 165 children. The prevalence of caries in the primary dentition was 32.7% and the dmft was 1.32, with the vast majority of teeth (84.9%) being decayed. The mean OHI‐S was 1.74. Most children had visited the dentist (61.0%) and ate cariogenic foods «sometimes» (76.2%). Over 80% of children brushed their teeth daily with parentś help and 66.7% started brushing between the first and third year. A positive association was found between caries and the visit to the dentist, and the age toothbrushing started.ConclusionsThe prevalence and severity of dental caries may be considered low. The oral health promotion activities should include information and motivation for healthy behaviours, specially, for the age of toothbrush beginning.

BsDyP from Bacillus subtilis belongs to the new dye-decolourising peroxidase (DyP) family. Here, we use transient kinetics to provide details on the catalytic cycle of BsDyP. The reaction of BsDyP with H2O2 exhibits saturation behaviour consistent with a two-step mechanism involving the formation of an E–H2O2 intermediate (K1 = (12 ± 1) × 10−6 M) followed by the formation of Compound I (k1 = 22 ± 1 s−1). We demonstrate that k1obs is pH-dependent and controlled by an ionisable group with a pKa of 4.3, suggesting the involvement of distal Asp. The reaction of Compound I with guaiacol obeys second-order kinetics (k3′ = (0.21 ± 0.01) × 106 M−1 s−1) while the reaction of Compound II with guaiacol shows saturation kinetics (K4 = (22 ± 5) × 10−6 M and k4 = 0.13 ± 0.01 s−1) and is the rate-limiting step in the BsDyP catalytic cycle. Furthermore, we use transient and steady-state kinetics as well as spectroscopic and electrochemical approaches to investigate the role of distal Asp240, Arg339 and Asn244 and proximal Asp383 residues in BsDyP. All mutations of distal residues affect particularly the K1 (and Km) for H2O2 leading to catalytic efficiencies (kcat/Km) of only one to two orders of magnitude lower than those in the wild-type. Notably, a significant improvement in the catalytic efficiency for reducing substrates is observed in the variants. We conclude that the Asp and Arg residues are important for the proper binding of H2O2 to the haem but none is individually indispensable for promoting H2O2 (de)protonation and O–O bond cleavage. The obtained kinetic data suggest an important role of distal Asn in modulating the acid–base catalysis of BsDyP. Our findings contribute to the establishment of structural determinants of DyPs that underlie their mechanistic properties; this has implications for their potential in biotechnological applications and sheds more light on the subfamily-dependent features of these enzymes.

The enzymatic degradation of azo dyes begins with the reduction of the azo bond. In this article, we report the crystal structures of the native azoreductase from Pseudomonas putida MET94 (PpAzoR) (1.60 Å), of PpAzoR in complex with anthraquinone-2-sulfonate (1.50 Å), and of PpAzoR in complex with Reactive Black 5 dye (1.90 Å). These structures reveal the residues and subtle changes that accompany substrate binding and release. Such changes highlight the fine control of access to the catalytic site that is required by the ping-pong mechanism, and in turn the specificity offered by the enzyme towards different substrates. The topology surrounding the active site shows novel features of substrate recognition and binding that help to explain and differentiate the substrate specificity observed among different bacterial azoreductases.

EnglishOne of the key factors in a software development process is the Interaction Design, Usability more precisely, largely responsible for the efficient use of a particular application. For this purpose, renowned designers like Dieter Rams, go even further, stating that the use of good design should make a product as understandable as to be self-explanatory, making the instructions manual unnecessary (Vitsœ, 2016). Does the application of good design principles make technology products so intuitive that they do not require the use of the User Manual? This study aims to present the perception of users regarding the use of qualitative analysis software User Guide webQDA®, understanding the level of frequency with which they refer to the manual, identifying operations that lead the users to resort to it, the supports in which the manual is more frequently consulted, among other information. portuguesUm dos fatores fundamentais no processo de desenvolvimento de um software e o Design de Interacao, mais precisamente a Usabilidade, responsavel, em grande parte, pela eficiente utilizacao de uma determinada aplicacao. Com esse proposito, designers conceituados como Dieter Rams, vao ainda mais longe, afirmando que o recurso ao bom design devera tornar um produto tao compreensivel, ao ponto de ser autoexplicativo, tornando desnecessario o recurso a Manual de Instrucoes (Vitsœ, 2016). Sera que a aplicacao dos principios de bom design torna os produtos tecnologicos tao intuitivos que dispensam o recurso ao Manual de Utilizador? Este estudo pretende dar a conhecer a percecao dos utilizadores relativamente ao uso do Manual de Utilizador do software de analise qualitativa webQDA®, ao nivel de frequencia com que e consultado, a identificacao das operacoes que levam o utilizador a recorrer ao Manual, em que tipo de suporte e mais explorado, entre outros.

ResumoOs pediatras e os médicos de família podem ter um importante papel na prevenção da cárie, devido ao contacto precoce com as crianças e com as suas famílias. Nas suas consultas podem promover bons comportamentos em saúde oral e incentivar a sua implementação desde cedo na vida.ObjetivoEstudar conhecimentos e práticas sobre saúde oral, de pediatras e médicos de família, bem como as barreiras sentidas relacionadas com a promoção da saúde oral na sua prática clínica.Material e métodosFoi aplicado um questionário a médicos de família do Agrupamento de Centros de Saúde de Almada, e a pediatras do Hospital Garcia de Orta e de uma clínica privada em Lisboa.ResultadosForam recolhidos 30 questionários, correspondendo a uma taxa de resposta 75%. Os participantes revelaram boas práticas, sendo as identificadas como menos realizadas a avaliação do risco de cárie (não efetuada por cerca de 10%) e a recomendação de cuidados especiais em pacientes com medicações frequentes (perto de 30% referiu não realizar). Estes profissionais revelaram possuir bons conhecimentos de saúde oral (valor médio 9,9 ± 1,82, num máximo possível de 12). Foram evidenciados menos conhecimentos relativamente à transmissão vertical de bactérias cariogénicas e à identificação dos primeiros sinais de cárie. A maioria dos médicos (89,3%) considerou ter um papel muito importante na promoção da saúde oral.ConclusõesDada a importância destes profissionais na prevenção primária e secundária da cárie, é fundamental melhorar a sua formação em saúde oral para corrigir algumas das suas práticas e aumentar os seus conhecimentos nesta área.AbstractPediatricians and family doctors can play an important role in the prevention of dental caries because of their early contact with children and their families.ObjectiveTo assess the oral health related knowledge and practices of pediatricians and family doctors and barriers related with oral health promotion.Material and MethodsApplication of a questionnaire distributed to family doctors working in the “Agrupamento de Centros de Saúde de Almada” and pediatricians working in the Hospital Garcia de Orta and in a private clinic in Lisbon.ResultsThirty questionnaires were collected, a 75% response rate. Aspects identified as less practiced by the participants were caries risk assessment (10%) and oral health recommendations for children taking chronic medication (about 30%). Regarding knowledge, the participants evidenced good oral health knowledge (mean 9.9±1.82, with a possible maximum of 12), and showed greater difficulties in questions about vertical transmission of cariogenic bacteria and identification of early signs of dental caries. Most of the study participants considered they have a very important role in children's oral health promotion (89.3%).ConclusionsBecause of the importance of these health care professionals in the primary and secondary prevention of dental caries, it is fundamental that they receive better training in oral health issues in order to improve their knowledge and correct some of their practices.

The azoreductase PpAzoR from Pseudomonas putida shows a broader specificity for decolourization of azo dyes than CotA-laccase from Bacillus subtilis. However, the final products of PpAzoR activity exhibited in most cases a 2 to 3-fold higher toxicity than intact dyes themselves. We show that addition of CotA-laccase to PpAzoR reaction mixtures lead to a significant drop in the final toxicity. A sequential enzymatic process was validated through the use of 18 representative azo dyes and three model wastewaters that mimic real dye-containing effluents. A heterologous Escherichia coli strain was successfully constructed co-expressing the genes coding for both PpAzoR and CotA. Whole-cell assays of recombinant strain for the treatment of model dye wastewater resulted in decolourization levels above 80% and detoxification levels up to 50%. The high attributes of this strain, make it a promising candidate for the biological treatment of industrial dye containing effluents.

The increasing interest in clinical bacterial photodynamic inactivation has led to the search for photosensitizers with higher bactericidal efficiency and less side effects on the surrounding tissues. We present a novel nonionic porphyrin, the 5,10,15-tris(2,6-dichlorophenyl)-20-[4-N-(6-amino-hexyl) sulfonamido)phenyl]-porphyrin (ACS769F4) with substantial improvements in the efficiency of nonionic sensitizers. This porphyrin causes eradication of both Escherichia coli and Staphylococcus aureus by the photodynamic effect but in higher concentrations compared with 5,10,15,20-tetrakis (4-N,N,N- trimethylammoniumphenyl)-porphyrin p-tosylate (TTAP 4+), a known bactericidal tetracationic porphyrin. More important, under such conditions, ACS769F4 proved to be harmless to two mammalian cells lines (human embryonic and baby hamster kidney), causing no reduction in their viability or negative impact on their cytoskeleton, despite its accumulation in cellular structures. On the contrary, TTAP 4+ is shown to accumulate in the nucleus of mammalian cells, in association to DNA, causing chromatin condensation after exposure to light. Furthermore, dark incubation with TTAP 4+ was shown to have a deleterious effect on the microtubule network. Based on its bactericidal efficiency, also observed without exposure to light, and on the low tendency to be harmful or genotoxic to mammalian cells, ACS769F4 should be looked at as an interesting photosensitizer to be evaluated for clinical purposes. A new nonionic porphyrin was synthesized and its properties as antibacterial agent by photodynamic effect were tested against Escherichia coli and Staphylococcus aureus. More relevant, this porphyrin proved to be harmless to two lines of mammalian cells (HEK and BHK cells), causing no reduction in their viability or negative impact on their cytoskeleton, despite its accumulation in cellular structures. On the contrary, a cationic porphyrin with a high efficiency as an antibacterial agent, under the same conditions, was shown to accumulate in the nucleus of mammalian cells, in association to DNA, causing chromatin condensation after exposure to light.

Azo dyes are the major group of synthetic colourants used in industry and are serious environmental pollutants. In this study, Pseudomonas putida MET94 was selected from 48 bacterial strains on the basis of its superior ability to degrade a wide range of structurally diverse azo dyes. P. putida is a versatile microorganism with a well-recognised potential for biodegradation or bioremediation applications. P. putida MET94 removes, in 24 h and under anaerobic growing conditions, more than 80% of the majority of the structurally diverse azo dyes tested. Whole cell assays performed under anaerobic conditions revealed up to 90% decolourisation in dye wastewater bath models. The involvement of a FMN dependent NADPH: dye oxidoreductase in the decolourisation process was suggested by enzymatic measurements in cell crude extracts. The gene encoding a putative azoreductase was cloned from P. putida MET94 and expressed in Escherichia coli. The purified P. putida azoreductase is a 40 kDa homodimer with broad substrate specificity for azo dye reduction. The presence of dioxygen leads to the inhibition of the decolourisation activity in agreement with the results of cell cultures. The kinetic mechanism follows a ping-pong bi-bi reaction scheme and aromatic amine products were detected in stoichiometric amounts by high-performance liquid chromatography. Overall, the results indicate that P. putida MET94 is a promising candidate for bioengineering studies aimed at generating more effective dye-reducing strains.

In this study we provide the first biochemical characterization of a bacterial pyranose 2-oxidase (AsP2Ox) from Arthrobacter siccitolerans. The enzyme catalyzes the oxidation of several aldopyranoses at the C-2 position, coupling it to the reduction of dioxygen to hydrogen peroxide. Pyranose 2-oxidases belong to the glucose-methanol-choline oxidoreductase family. A structural model based on the known X-ray structure of P2Ox from Phanerochaete chrysosporium supports that AsP2Ox shares structural features with well-characterized fungal P2Oxs. The gene coding for AsP2Ox was cloned and heterologously expressed in Escherichia coli. The purified recombinant enzyme is a 64-kDa monomer containing a non-covalently bound flavin adenine dinucleotide (FAD) cofactor, distinct features as compared with fungal counterparts that are ∼ 270 kDa homotetramers with covalent-linked FAD. AsP2Ox exhibits a redox potential of −50 mV, an optimum temperature of 37 °C and an optimum pH at 6.5. AsP2Ox oxidizes d -glucose at the highest efficiency, using additionally d -galactose, d -xylose, l -arabinose and d -ribose as electron donors, coupling their oxidation to the reduction of both dioxygen and 1,4-benzoquinone. AsP2Ox shows a relatively low thermal stability with a melting temperature (Tm) of 43 °C and a half-life (t1/2) at 40 °C of 25 min. This work expands the repertoire of bacterial oxidoreductases with importance in biotechnological and diagnostic applications.