Synthesis and photophysical characterization of dimethylamine-derived Zn(II)phthalocyanines: exploring their potential as selective chemosensors for trinitrophenol

We report a novel synthetic approach, with good yields, for the synthesis of selective dimethylamine-substituted phthalonitriles (1-3) in the presence of triethyl phosphite and dimethylformamide at 160 degrees C. The peripherally modified dimethylamine substituted Zn(II) phthalocyanines (ZnPc1-3) with varied numbers and positions of dimethylamine groups were prepared for a systematic investigation of the effect of the substituents on their electronic and spectroscopic properties. Compounds show strong aggregation behaviour in methanol and this behaviour decreases with the increase of the alkyl chain length of the alcohol solvents (i.e., from methanol to octanol). The fluorescence quantum yields of ZnPc1-3 showed an excellent correlation with the extent of the molecular aggregation. The versatility of the ZnPc1-5 compounds possessing both electron donating and electron withdrawing substituents at their periphery is investigated towards the detection of nitroaromatic compounds (NACs) in solution and in the vapour phase. It was found that ZnPc1-5 exhibit high selectivity towards trinitrophenol (TNP). A good linearity of fluorescence detection using ZnPc3 as the fluorescent probe was observed in the concentration range of 50 x 10(-6) to 450 x 10(-6) M in chloroform, with a detection limit (LOD) of 11 +/- 2 ppm. Stern-Volmer (SV) and DFT studies reveal that the fluorescence quenching behaviour occurs through photo-induced electron transfer from the excited state of ZnPcs to TNP with static quenching behaviour occurring in a predominant fashion. The formation of a porous morphology of ZnPc3 thin films promotes high selectivity and accessibility to TNP vapours (7.7 x 10(-3) ppb)

Photodynamic inactivation of Escherichia coli with cationic ammonium Zn(II) phthalocyanines

The aim of this work was the development of a family of novel water soluble Zinc(II) phthalocyanines (Pc) for the photodynamic inactivation of Gram-negative bacteria. Pc derivatives 1a, 2a and 3a containing trimethylammonium groups with varied number and nature of the groups at peripheral positions were synthesized by cyclotetramerization of dimethyl amino substituted phthalonitriles in the presence of zinc powder, using 1-chloronaphthalene as a solvent, followed by cationization using dimethyl sulfate. The solubility, singlet oxygen generation (O-1(2)) and stability/photostability of each Pc were evaluated as well as the affinity to bacterial cells and their photosensitizing potential against a recombinant bioluminescent Escherichia coli strain, used as a biological model for Gram negative bacteria. The efficiency of photodynamic inactivation was assessed under white and red light at an irradiance of 150 mW cm(-2). All Pc were soluble in phosphate buffer saline and in dimethyl sulfoxide and demonstrated good stability/photostability. The photochemical parameters reveal that Pc 2a and 3a are more efficient singlet oxygen producers than Pc 1a, for which singlet oxygen generation could not be demonstrated. Pc 2a and 3a caused photosensitization in E. coli. The inactivation factors attained with red light were, however, generally higher than those with white light. Under red light Pc 3a and 2a caused, respectively, 5.6 and 4.9 log reduction in the bioluminescence of the E. coli while, with white light, the corresponding inactivation factors were 2.5 and 0.5 log. The order of the PDI efficiency (3a > 2a >>> 1a) was determined by the combined effect of solubility, singlet oxygen generation ability and affinity to bacterial cells. Ammonium phthalocyanines with eight charges or containing halogen atoms such as chlorine, when irradiated with red light can, therefore, be regarded as promising photosensitizers for the inactivation of Gram-negative bacteria

Heterogeneous Streptomycin Resistance Level Among Mycobacterium tuberculosis Strains From the Same Transmission Cluster

12 páginas, 5 figuras.Widespread and frequent resistance to the second-line tuberculosis (TB) medicine streptomycin, suggests ongoing transmission of low fitness cost streptomycin resistance mutations. To investigate this hypothesis, we studied a cohort of 681 individuals from a TB epidemic in Portugal. Whole-genome sequencing (WGS) analyses were combined with phenotypic growth studies in culture media and in mouse bone marrow derived macrophages. Streptomycin resistance was the most frequent resistance in the cohort accounting for 82.7% (n = 67) of the resistant Mycobacterium tuberculosis isolates. WGS of 149 clinical isolates identified 13 transmission clusters, including three clusters containing only streptomycin resistant isolates. The biggest cluster was formed by eight streptomycin resistant isolates with a maximum of five pairwise single nucleotide polymorphisms of difference. Interestingly, despite their genetic similarity, these isolates displayed different resistance levels to streptomycin, as measured both in culture media and in infected mouse bone marrow derived macrophages. The genetic bases underlying this phenotype are a combination of mutations in gid and other genes. This study suggests that specific streptomycin resistance mutations were transmitted in the cohort, with the resistant isolates evolving at the cluster level to allow low-to-high streptomycin resistance levels without a significative fitness cost. This is relevant not only to better understand transmission of streptomycin resistance in a clinical setting dominated by Lineage 4 M. tuberculosis infections, but mainly because it opens new prospects for the investigation of selection and spread of drug resistance in general.This work has been funded by of the projects NORTE-01-0145- FEDER-000039, NORTE-01-0145-FEDER-000013, and NORTE01-0145-FEDER-00002, supported by Norte Portugal Regional Operational Program (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). It was also funded through the Foundation for Science and Technology (FCT) – project FCT IF/00474/2014, UIDB/50026/2020 and UIDP/50026/2020. DR and CM were funded by FCT Ph.D. scholarships (grant numbers SFRH/BD/135422/2017 and SFRH/BD/132797/2017, respectively). DR was partially funded by the PGCD – Graduate Program Science for Development. MS is supported by FCT through the Estimulo ao Emprego Científico.Peer reviewe

Sociodemographic Characteristics, Behavioral Problems, Parental Concerns and Children’s Strengths Reported by Parents

Parental report is essential to understand adaptive difficulties in childhood. The aim of the study was to identify concerns of parents and qualities of children reported by parents, as well as the association of these variables with sociodemographic factors and child behavior problems. Parents of 353 schoolchildren from three public schools and one private school took part in the study. Assessment of behavior problems and parental reports about concerns and children’s strengths were obtained from the Child Behavior Checklist - CBCL. We submitted parents’ answers to the open-ended questions in the CBCL to a lexical analysis with the IRAMUTEQ software. Results concerning ‘strengths’ were related to affective and social interaction, while ‘concerns’ were related to academic performance and prevention of behavior problems. We concluded that parent concerns are targets of preventive interventions in childhood, while child strengths reported by parents are skills that need to be developed, as they help in adaptive functioning.El relato de padres es esencial para la comprensión de dificultades adaptativas de niños. Los objetivos de este estudio fueron identificar preocupaciones y cualidades relatadas por padres y verificar sus asociaciones con fatores sociodemográficos y problemas de conducta. Fueron participantes 353 padres de alumnos de cuatro escuelas públicas y una privada. La evaluación de problemas de comportamiento de los hijos y el relato de los padres sobre preocupaciones y cualidades fueron obtenidos con la Lista de Comportamientos para Niños y Adolescentes (CBCL). Conducimos un análisis lexical de las respuestas a las preguntas abiertas de la CBCL mediante el software IRAMUTEQ. Los resultados sobre las cualidades del niño fueron relacionados con la interacción afectiva y social. Las preocupaciones estuvieron relacionadas al desempeño académico y la prevención de problemas de comportamiento. Concluimos que las preocupaciones de los padres indican metas para intervenciones preventivas en la infancia, mientras que las cualidades, si desarrolladas, podrán auxiliar el funcionamento adaptativo.O relato de pais é essencial na compreensão de dificuldades adaptativas na infância. O objetivo do estudo foi identificar preocupações dos pais e qualidades dos filhos, relatadas pelos pais, bem como a associação dessas variáveis com fatores sociodemográficos e problemas de comportamento das crianças. Participaram 353 pais de alunos de três escolas públicas e uma escola privada. A avaliação de problemas de comportamento dos filhos e o relato dos pais sobre preocupações e qualidades foram obtidos com o Inventário de Comportamentos para Crianças e Adolescentes - CBCL. As respostas às questões abertas do CBCL foram submetidas à análise lexical no software IRAMUTEQ. Resultados sobre qualidades da criança foram relacionados à interação afetiva e social. As preocupações foram relacionadas a desempenho acadêmico e prevenção de problemas de comportamento. Concluímos que as preocupações relatadas são indicativas de alvos para intervenções preventivas e as qualidades, se desenvolvidas, poderão auxiliar no funcionamento adaptativo

Growing knowledge: an overview of Seed Plant diversity in Brazil

Abstract An updated inventory of Brazilian seed plants is presented and offers important insights into the country's biodiversity. This work started in 2010, with the publication of the Plants and Fungi Catalogue, and has been updated since by more than 430 specialists working online. Brazil is home to 32,086 native Angiosperms and 23 native Gymnosperms, showing an increase of 3% in its species richness in relation to 2010. The Amazon Rainforest is the richest Brazilian biome for Gymnosperms, while the Atlantic Rainforest is the richest one for Angiosperms. There was a considerable increment in the number of species and endemism rates for biomes, except for the Amazon that showed a decrease of 2.5% of recorded endemics. However, well over half of Brazillian seed plant species (57.4%) is endemic to this territory. The proportion of life-forms varies among different biomes: trees are more expressive in the Amazon and Atlantic Rainforest biomes while herbs predominate in the Pampa, and lianas are more expressive in the Amazon, Atlantic Rainforest, and Pantanal. This compilation serves not only to quantify Brazilian biodiversity, but also to highlight areas where there information is lacking and to provide a framework for the challenge faced in conserving Brazil's unique and diverse flora