This study investigated the antimicrobial and antibiotic-potentiating activities of two novel ruthenium complexes against clinically relevant bacterial strains. The complexes cis-[RuCl₂(dppb)(NN-F)] and cis-[RuCl₂(dppb)(NN-Br)] exhibited activity against Staphylococcus aureus and Staphylococcus epidermidis, with minimum inhibitory concentrations (MICs) ranging from 7.8 to 62.5 µg·ml^-1 and minimum bactericidal concentrations (MBCs) from 31.25 to 125 µg·ml^-1. When combined with ampicillin, both complexes demonstrated synergistic effects. Time-kill assays showed bactericidal activity within the first 2 to 12 h. The complexes significantly reduced biofilm biomass, viable cell counts and metabolic activity in both biofilm formation and mature biofilms. Microscopy revealed membrane damage and increased generation of reactive oxygen species (ROS) in S. aureus biofilms. Cytotoxicity assays confirmed low toxicity toward L929 fibroblasts (≤31.2 µg·ml^-1) and minimal hemolytic activity (1-13%). These findings support the potential of these ruthenium complexes as candidates for novel therapies against staphylococcal infections.

Antimicrobial resistance (AMR) is a critical global public health problem. Many bacterial pathogens use biofilm formation as their main pathogenicity mechanism, a practical tactic for surviving in natural settings and colonized host tissues. Research using ruthenium(II) complexes has demonstrated antibacterial action linked to photodynamic therapy, an alternate method of microbial control. Thus, in this work, the photosensitive nitro complex [RuCl(NO₂)(dppb)(4,4-Mebipy)] (I) was prepared and the X-ray structure was determined. Then, we investigated the antibacterial and antibiofilm activities, antibiotic-associated effects, and cytotoxicity. The results showed that complex I exhibited promising antimicrobial activity with MIC values ranging from 4 to 256 µg/mL and MBC from 4 to 32 µg/mL. The antimicrobial activity of this nitro complex was significantly enhanced with blue light irradiation, as confirmed by agarose gel electrophoresis of the pBR322 DNA, which must be related to the DNA cleavage promoted by the photorelease of NO. A synergistic effect against Staphylococcus aureus and Staphylococcus epidermidis strains was observed when combined with ampicillin, which exhibited FICI values from 0.186 to 0.311. Interestingly, complex I associated with tetracycline showed a synergistic effect only on Escherichia coli. Regarding biofilms, the irradiated complex I showed antibacterial activity against biofilm formation and mature biofilms. Furthermore, SEM and confocal analyses revealed changes in cell morphology and damage to the wall and plasma membrane. Complex I presented a percentage of hemolysis between 2 and 4%, and no cytotoxic effect was observed against murine dermal fibroblasts. In conclusion, the photoactivated ruthenium(II) complex showed antibacterial and antibiofilm activity against relevant bacteria.

Introdução: O câncer é o nome dado a um conjunto de mais de 100 doenças que tem em comum o crescimento desordenado de células, as quais podem, inclusive, invadir outros tecidos, ocasionando alto índice de mortalidade, assim sendo estabelecido como um importante problema de saúde pública. Células tumorais apresentam alterações significativas na expressão de glicoproteínas em suas superfícies e sua detecção precoce é uma etapa definitiva para a cura durante o tratamento. Na busca por novas moléculas com potencial biotecnológico, vários estudos de prospecção têm sido realizados em habitats marinhos. Lectinas oriundas dos habitats marinhos demonstram relevante potencial biotecnológico, na qual várias atividades biológicas estão descritas na literatura. Tendo em vista a frequente expressão de padrões aberrantes de glicosilação nas células tumorais, as lectinas por serem proteínas com capacidade de ligação seletiva a carboidratos surgem como promissores agentes antineoplásicos. Objetivo: Este trabalho objetivou avaliar a atividade antitumoral da lectina isolada da esponja marinha Chondrilla caribensis (CCL) sobre células de carcinoma de próstata (LNCaP), bem como analisar o perfil de citotoxicidade da CCL sobre a linhagem de queratinócitos normais (HaCaT). Material e Métodos: O efeito citotóxico da CCL foi avaliado através do ensaio de viabilidade celular usando o método colorimétrico do sal tetrazolium MTS para as células das linhagens LNCaP e HaCaT. As linhagens celulares foram expostas a concentrações de 500 a 7,8 µg.ml-1 de CCL por 48 h. Resultados: Os resultados mostraram uma redução de 76,71% na viabilidade de LNCaP nas concentrações de 500, 250 e 125 µg.ml-1 (IC50 = 44,31 µg.ml-1). Para a linhagem celular HaCaT, o tratamento com CCL nas concentrações de 500, 250 e 125 µg.ml-1 resultou na redução da viabilidade em 28,64 %; 12,24 % e 0,76 %, respectivamente, onde 71,36 % ± 0,588 das células HaCaT permaneceram viáveis após 48 h de tratamento. Conclusão: Em conclusão, os resultados sugerem que a CCL possui maior seletividade para a linhagem LNCaP, e em contrapartida apresentou toxicidade reduzida sobre queratinócitos humanos saudáveis. Estudos adicionais devem ser realizados para investigar o mecanismo de ação da CCL sobre as células utilizadas no estudo.

The objective of this study is to report the experience lived by extensionists of the Immunology project in Professional Schools of Fortaleza in an internal training on Vaccines and Covid-19. This is an exploratory and descriptive study, of a qualitative and quantitative nature, carried out through the Google Meet videoconferencing application and the Google Forms survey management application. Students from undergraduate courses in health sciences and biological sciences linked to the extension project participated in the activity, as well as students and professors from postgraduate programs at the Federal University of Ceará (UFC). Among the results, distance communication technologies through the dissemination of didactic content make the teaching and learning process possible, effectively and playfully enabling the transfer of knowledge and interaction between people without the need for direct contact in the same physical environment. Through globalized communication tools, it is possible to ensure effectiveness in learning and disseminating content related to a particular theme. In conclusion, the teaching and learning activity carried out by virtual means was successful. The project public was able to expand knowledge about immunology, focusing on the constituent inputs of the vaccine against Covid-19, promoting the dissemination of knowledge during the online meeting.