A Practical Toolkit for the Detection, Isolation, Quantification, and Characterization of Siderophores and Metallophores in Microorganisms.

Siderophores are well-recognized low-molecular-weight compounds produced by numerous microorganisms to acquire iron from the surrounding environments. These secondary metabolites can form complexes with other metals besides iron, forming soluble metallophores; because of that, they are widely investigated in either the medicinal or environmental field. One of the bottlenecks of siderophore research is related to the identification of new siderophores from microbial sources. Herein we have compiled a comprehensive range of standard and updated methodologies that have been developed over the past few years to provide a comprehensive toolbox in this area to current researchers.

Siderophores and metallophores: Metal complexation weapons to fight environmental pollution.

Siderophores are small molecules of organic nature, released by bacteria to chelate iron from the surrounding environment and subsequently incorporate it into the cytoplasm. In addition to iron, these secondary metabolites can complex with a wide variety of metals, which is why they are commonly studied in the environment. Heavy metals can be very toxic when present in large amounts on the planet, affecting public health and all living organisms. The pollution caused by these toxic metals is increasing, and therefore it is urgent to find practical, sustainable, and economical solutions for remediation. One of the strategies is siderophore-assisted bioremediation, an innovative and advantageous alternative for various environmental applications. This research highlights the various uses of siderophores and metallophores in the environment, underscoring their significance to ecosystems. The study delves into the utilization of siderophores and metallophores in both marine and terrestrial settings (e.g. bioremediation, biocontrol of pathogens, and plant growth promotion), such as bioremediation, biocontrol of pathogens, and plant growth promotion, providing context for the different instances outlined in the existing literature and highlighting their relevance in each field. The study delves into the structures and types of siderophores focusing on their singular characteristics for each application and methodologies used. Focusing on recent developments over the last two decades, the opportunities and challenges associated with siderophores and metallophores applications in the environment were mapped to arm researchers in the fight against environmental pollution.

Correction: Palmeira et al. Preliminary Virtual Screening Studies to Identify GRP78 Inhibitors Which May Interfere with SARS-CoV-2 Infection. Pharmaceuticals 2020, 13, 132.

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Preliminary hazard assessment of a new nature-inspired antifouling (NIAF) agent.

A recently synthesized aminated 3,4-dioxygenated xanthone (Xantifoul2) was found to have promising antifouling (AF) effects against the settlement of the macrofouler Mytilus galloprovincialis larvae. Preliminary assessment indicated that Xantifoul2 has reduced ecotoxicological impacts: e.g., being non-toxic to the marine crustacea Artemia salina (<10 % mortality at 50 µM) and showing low bioconcentration factor in marine organisms. In order to meet the EU Biocidal Product Regulation, a preliminary hazard assessment of this new nature-inspired antifouling (NIAF) agent was conducted in this work. Xantifoul2 did not affect the swimming ability of the planktonic crustacean Daphnia magna, the growth of the diatom Phaeodactylum tricornutum, and the cellular respiration of luminescent Gram-negative bacteria Vibrio fischeri, supporting the low toxicity towards several non-target marine species. Regarding human cytotoxicity, Xantifoul2 did not affect the cell viability of retinal human cells (hTERT-RPE-1) and lipidomic studies revealed depletion of lipids involved in cell death, membrane modeling, lipid storage, and oxidative stress only at a high concentration (10 µM). Accelerated degradation studies in water were conducted under simulated sunlight to allow the understanding of putative transformation products (TPs) that could be generated in the aquatic ecosystems. Both Xantifoul2 and photolytic-treated Xantifoul2 in the aqueous matrix were therefore evaluated on several nuclear receptors (NRs). The results of this preliminary hazard assessment of Xantifoul2, combined with the high degradation rates in water, provide strong evidence of the safety of this AF agent under the evaluated conditions, and provide the support for future validation studies before this compound can be introduced in the market.

Comparative In Vitro Study of the Cytotoxic Effects of Doxorubicin's Main Metabolites on Cardiac AC16 Cells Versus the Parent Drug.

Doxorubicin (DOX; also known as adriamycin) serves as a crucial antineoplastic agent in cancer treatment; however, its clinical utility is hampered by its' intrinsic cardiotoxicity. Although most DOX biotransformation occurs in the liver, a comprehensive understanding of the impact of DOX biotransformation and its' metabolites on its induced cardiotoxicity remains to be fully elucidated. This study aimed to explore the role of biotransformation and DOX's main metabolites in its induced cardiotoxicity in human differentiated cardiac AC16 cells. A key discovery from our study is that modulating metabolism had minimal effects on DOX-induced cytotoxicity: even so, metyrapone (a non-specific inhibitor of cytochrome P450) increased DOX-induced cytotoxicity at 2 µM, while diallyl sulphide (a CYP2E1 inhibitor) decreased the 1 µM DOX-triggered cytotoxicity. Then, the toxicity of the main DOX metabolites, doxorubicinol [(DOXol, 0.5 to 10 µM), doxorubicinone (DOXone, 1 to 10 µM), and 7-deoxydoxorubicinone (7-DeoxyDOX, 1 to 10 µM)] was compared to DOX (0.5 to 10 µM) following a 48-h exposure. All metabolites evaluated, DOXol, DOXone, and 7-DeoxyDOX caused mitochondrial dysfunction in differentiated AC16 cells, but only at 2 µM. In contrast, DOX elicited comparable cytotoxicity, but at half the concentration. Similarly, all metabolites, except 7-DeoxyDOX impacted on lysosomal ability to uptake neutral red. Therefore, the present study showed that the modulation of DOX metabolism demonstrated minimal impact on its cytotoxicity, with the main metabolites exhibiting lower toxicity to AC16 cardiac cells compared to DOX. In conclusion, our findings suggest that metabolism may not be a pivotal factor in mediating DOX's cardiotoxic effects.

Antibacterial Potential of Symmetrical Twin-Drug 3,6-Diaminoxanthones.

Global health faces a significant issue with the rise of infectious diseases caused by bacteria, fungi, viruses, and parasites. The increasing number of multi-drug resistant microbial pathogens severely threatens public health worldwide. Antibiotic-resistant pathogenic bacteria, in particular, present a significant challenge. Therefore, there is an urgent need to identify new potential antimicrobial targets and discover new chemical entities that can potentially reverse bacterial resistance. The main goal of this research work was to create and develop a library of 3,6-disubstituted xanthones based on twin drugs and molecular extension approaches to inhibit the activity of efflux pumps. The process involved synthesizing 3,6-diaminoxanthones through the reaction of 9-oxo-9H-xanthene-3,6-diyl bis(trifluoromethanesulfonate) with various primary and secondary amines. The resulting 3,6-disubstituted xanthone derivatives were then tested for their in vitro antimicrobial properties against a range of pathogenic strains and their efficacy in inhibiting the activity of efflux pumps, biofilm formation, and quorum-sensing. Several compounds have exhibited effective antibacterial properties against the Gram-positive bacterial species tested. Xanthone 16, in particular, has demonstrated exceptional efficacy with a remarkable MIC of 11 µM (4 µg/mL) against reference strains Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212, and 25 µM (9 µg/mL) against methicillin-resistant S. aureus 272123. Furthermore, some derivatives have shown potential as antibiofilm agents in a crystal violet assay. The ethidium bromide accumulation assay pinpointed certain compounds inhibiting bacterial efflux pumps. The cytotoxic effect of the most promising compounds was examined in mouse fibroblast cell line NIH/3T3, and two monoamine substituted xanthone derivatives with a hydroxyl substituent did not exhibit any cytotoxicity. Overall, the nature of the substituent was critical in determining the antimicrobial spectra of aminated xanthones.

The Synthesis and Characterization of a Delivery System Based on Polymersomes and a Xanthone with Inhibitory Activity in Glioblastoma.

Glioblastoma (GBM) is the most common and deadly primary malignant brain tumor. Current therapies are insufficient, and survival for individuals diagnosed with GBM is limited to a few months. New GBM treatments are urgent. Polymeric nanoparticles (PNs) can increase the circulation time of a drug in the brain capillaries. Polymersomes (PMs) are PNs that have been described as having attractive characteristics, mainly due to their stability, prolonged circulation period, biodegradability, their ability to sustain the release of drugs, and the possibility of surface functionalization. In this work, a poly(ethylene glycol)-ε-caprolactone (PEG-PCL) copolymer was synthesized and PMs were prepared and loaded with an hydrolytic instable compound, previously synthesized by our research team, the 3,6-bis(2,3,4,6-tetra-O-acetyl-ß-glucopyranosyl)xanthone (XGAc), with promising cytotoxicity on glioblastoma cells (U-373 MG) but also on healthy cerebral endothelial cells (hCMEC/D3). The prepared PMs were spherical particles with uniform morphology and similar sizes (mean diameter of 200 nm) and were stable in aqueous suspension. The encapsulation of XGAc in PMs (80% encapsulation efficacy) protected the healthy endothelial cells from the cytotoxic effects of this compound, while maintaining cytotoxicity for the glioblastoma cell line U-373 MG. Our studies also showed that the prepared PMs can efficiently release XGAc at intratumoral pHs.

Therapeutic Potential of Marine-Derived Cyclic Peptides as Antiparasitic Agents.

Parasitic diseases still compromise human health. Some of the currently available therapeutic drugs have limitations considering their adverse effects, questionable efficacy, and long treatment, which have encouraged drug resistance. There is an urgent need to find new, safe, effective, and affordable antiparasitic drugs. Marine-derived cyclic peptides have been increasingly screened as candidates for developing new drugs. Therefore, in this review, a systematic analysis of the scientific literature was performed and 25 marine-derived cyclic peptides with antiparasitic activity (1-25) were found. Antimalarial activity is the most reported (51%), followed by antileishmanial (27%) and antitrypanosomal (20%) activities. Some compounds showed promising antiparasitic activity at the nM scale, being active against various parasites. The mechanisms of action and targets for some of the compounds have been investigated, revealing different strategies against parasites.

Antitumor Activity of the Xanthonoside XGAc in Triple-Negative Breast, Ovarian and Pancreatic Cancer by Inhibiting DNA Repair.

Dysregulation of the DNA damage response may contribute to the sensitization of cancer cells to DNA-targeting agents by impelling cell death. In fact, the inhibition of the DNA repair pathway is considered a promising anticancer therapeutic strategy, particularly in combination with standard-of-care agents. The xanthonoside XGAc was previously described as a potent inhibitor of cancer cell growth. Herein, we explored its antitumor activity against triple-negative breast cancer (TNBC), ovarian cancer and pancreatic ductal adenocarcinoma (PDAC) cells as a single agent and in combination with the poly(ADP-ribose) polymerase inhibitor (PARPi) olaparib. We demonstrated that XGAc inhibited the growth of TNBC, ovarian and PDAC cells by inducing cell cycle arrest and apoptosis. XGAc also induced genotoxicity, inhibiting the expression of DNA repair proteins particularly involved in homologous recombination, including BRCA1, BRCA2 and RAD51. Moreover, it displayed potent synergistic effects with olaparib in TNBC, ovarian cancer and PDAC cells. Importantly, this growth inhibitory activity of XGAc was further reinforced in a TNBC spheroid model and in patient-derived ovarian cancer cells. Also, drug-resistant cancer cells showed no cross-resistance to XGAc. Additionally, the ability of XGAc to prevent cancer cell migration was evidenced in TNBC, ovarian cancer and PDAC cells. Altogether, these results highlight the great potential of acetylated xanthonosides such as XGAc as promising anticancer agents against hard-to-treat cancers.

Comparative Studies on the Photoreactivity, Efficacy, and Safety of Depigmenting Agents.

Depigmenting products are increasingly used to counteract skin hyperpigmentation and related psychosocial issues. This study aimed to compare different depigmenting agents-4-butylresorcinol; bakuchiol; tranexamic acid; ascorbyl glucoside; α-arbutin; and ascorbic acid-for photoreactivity; tyrosinase inhibition; and safety. Photoreactivity was assessed using the Reactive Oxygen Species assay. In vitro tyrosinase inhibition was compared, and cell viability was assessed in B-16V melanocytes to evaluate safety. Results showed 4-butylresorcinol, ascorbyl glucoside, and α-arbutin are non-photoreactive, while for ascorbic acid and bakuchiol it was not possible to reach conclusive results due to the lack of specificity of the ROS assay. 4-Butylresorcinol, acting as a competitive inhibitor, displayed potent tyrosinase inhibition, followed by ascorbic acid and bakuchiol. Both 4-butylresorcinol and bakuchiol reduced cell viability in a concentration-dependent manner. The insights obtained in this work support the development of depigmenting products by providing useful scientific guidance on the photostability, tyrosinase inhibitory efficacy, and skin safety of depigmenting agents.

Alterações histopatológicas e imuno-histoquímicas miocárdicas em 117 casos fatais de dengue / Mytopathological and myocardial immunohistochemical changes in 117 fatal cases of dengue

Introdução: Os vírus dengue (DENV1-4) são os arbovírus humanos de maior importância médica no mundo. No Ceará, Nordeste brasileiro, a dengue é endêmica desde 1986, quando foi isolado o sorotipo DENV-1. Foram registradas sete grandes epidemias em 1987, 1994, 2001, 2008, 2011, 2012 e 2015. Estudos demonstram que formas graves podem estar associadas à manifestações cardíacas. Clinicamente a miocardite, pode ser aguda, crônica ou em atividade persistente e fulminante. Podemos ainda classificar a miocardite pelos achados histopatológicos, como miocardite linfocítica, sendo esse o padrão mais comumente encontrado associado à etiologia viral. Os mecanismos relacionados com o acometimento cardíaco incluem efeitos diretos do DENV no miocárdio e efeitos indiretos da resposta inflamatória desencadeada pela infecção culminando na liberação de citocinas vasoativas pró-inflamatórias, responsáveis pelo extravasamento vascular e inflamação miocárdica. Igualmente à miocardite fulminante de outras etiologias, a miocardite durante a infecção pelo DENV está associada à alta mortalidade. Objetivos: Geral: Descrever as alterações morfológicas e imunoinflamatórias no miocárdio dos casos fatais de dengue no Ceará no período de 2011-2013

Específicos: Descrever características demográficas, clínicas e laboratoriais dos casos. Identificar e quantificar as alterações morfológicas; Determinar a frequência de miocardite; Definir a frequência de apoptose; Quantificar linfócitos T CD4 e CD8, macrófagos (CD68) e marcador endotelial CD31 presentes no miocárdio e correlacioná-los com os achados morfológicos; Verificar a expressão das proteínas NS1 e NS3. Metodologia: Estudo retrospectivo do tipo série de casos, avaliou 117 amostras de miocárdio de casos confirmados de dengue e autopsiados no SVO-Ce de janeiro/2011 a dezembro/2013, quanto a dados demográficos, clínicos, laboratoriais. A análise histopatológica na coloração do HE, avaliou alterações morfológicas incluindo edema, hemorragia, necrose, fibrose e infiltrado inflamatório. Utilizamos os critérios de Dallas e da WHO/ISFC para o diagnóstico da miocardite. Anticorpos monoclonais anti-CD4, anti-CD8, anti-CD68, anti-CD31, anti-NS1 e anti-NS3 foram usados na identificação das células mononucleares, das células CD31+ e para avaliação de proteínas virais por imuno-histoquimica respectivamente. Apoptose foi avaliada pela técnica TUNEL.

Resultados: Foi encontrado alto percentual de miocardite nos pacientes (47/117,40,2%) sem distinção entre sexo e idade. Os sorotipos x identificados foram DENV1, DENV3 e DENV4. Análises histopatológicas revelaram áreas com edema, hemorragia e necrose do tecido cardíaco; No entanto, a hemorragia e a necrose foram significativamente maiores nos pacientes com miocardite. Maior frequência de células expressando a molécula CD31/PECAM-1 foram encontradas nos pacientes com miocardite. Por outro lado, encontramos maior frequência de células apoptóticas nos casos sem miocardite. As proteínas NS1 e NS3 foram detectadas em macrófagos e cardiomiócitos dos dois grupos analisados. Conclusão: A análise imuno-histoquímica revelou ser 15% mais eficiente na identificação da miocardite em comparação com a análise histopatológica. Não encontramos parâmetros bioquímicos, hematológicos ou demográficos que pudessem estar associados ao risco de desenvolvimento de miocardite. Não houve suspeita clínica em nenhum dos casos estudados. Embora, existam muitas lacunas no entendimento dos mecanismos envolvidos na patogênese da miocardite induzida pela infecção, este trabalho aponta a necessidade de serem propostos pelas entidades médicas e governamentais protocolos para a instauração de propedêutica cardíaca eficiente nos casos de dengue grave. (AU)

Mortalidade materna: Hospital Geral de Fortaleza (1975-1991) / Maternal mortality: Hospital Geral de Fortaleza (1975-1991)

Quarenta e três mortes maternas ocorreram na Clínica Obstétrica do Hospital Geral de Fortaleza Sistema Estadual de Saúde (HGF-SES), no período de janeiro de 1975 a julho de 1991. As causas obstétricas diretas contribuiram com um maior percentual (69,77 por cento), sendo eclâmpsia, hemorragia e infecçao as principais afecçoes em ordem decrescente de freqüência, seguidas pelas causas obstétricas indiretas (ll,63 por cento)e as nao-obstétricas (6,98 por cento). Comparamos dois períodos: janeiro de 1975 a dezembro de 1987, com um coeficiente de mortalidade matema (CMM) de 206, e janeiro de l988 a julho de l99l, comum CMM de lO4, everificamos uma diminuiçao significativa do mesmo, apesar de este ser ainda alto, visto que nosso serviço atende gestantes de risco. Observamos, ainda, que a maioria das mortes matemas sao evitáveis, sendo necessária a instalaçao de um melhor programa de saúde pública.