Publicações
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Leptochelins A–C, Cytotoxic Metallophores Produced by Geographically Dispersed Leptothoe Strains of Marine Cyanobacteria
Avalon, N. E., Reis, M. A., Thornburg, C. C., Williamson, R. T., Petras, D., Aron, A. T., Neuhaus, G. F., Al-Hindy, M., Mitrevska, J., Ferreira, L., Morais, J., el Abiead, Y., Glukhov, E., Alexander, K. L., Vulpanovici, F. A., Bertin, M. J., Whitner, S., Choi, H., Spengler, G., … Gerwick, W. H.
Abstract: Metals are important cofactors in the metabolic processes of cyanobacteria, including photosynthesis, cellular respiration, DNA replication, and the biosynthesis of primary and secondary metabolites. In adaptation to the marine environment, cyanobacteria use metallophores to acquire trace metals when necessary as well as to reduce potential toxicity from excessive metal concentrations. Leptochelins A−C were identified as structurally novel metallophores from three geographically dispersed cyanobacteria of the genus Leptothoe. Determination of the complex structures of these metabolites presented numerous challenges, but they were ultimately solved using integrated data from NMR, mass spectrometry and deductions from the biosynthetic gene cluster. The leptochelins are comprised of
halogenated linear NRPS-PKS hybrid products with multiple heterocycles that have potential for hexadentate and tetradentate coordination with metal ions. The genomes of the three leptochelin producers were sequenced, and retrobiosynthetic analysis revealed one candidate biosynthetic gene cluster (BGC) consistent with the structure of leptochelin. The putative BGC is highly homologous in all three Leptothoe strains, and all possess genetic signatures associated with metallophores. Postcolumn infusion of metals using an LC-MS metabolomics workflow performed with leptochelins A and B revealed promiscuous binding of iron, copper, cobalt, and zinc, with greatest preference for copper. Iron depletion and copper toxicity experiments support the hypothesis that
leptochelin metallophores may play key ecological roles in iron acquisition and in copper detoxification. In addition, the leptochelins possess significant cytotoxicity against several cancer cell lines.https://pubs.acs.org/doi/10.1021/jacs.4c05399?ref=pdf
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Microbial response to a port fuel spill: community dynamics and potential for bioremediation
Rafaela Perdigão, Maria Paola Tomasino, Catarina Magalhães, Maria F. Carvalho, C. Marisa R. Almeida and Ana P. Mucha
Abstract: Following a fuel leakage inside a Portuguese maritime port, we conducted parallel 30-day experiments using contaminated seawater and fuel, sampled five days after the incident. This study aimed to (i)survey the native microbial community response to the spilled fuel and (ii)evaluate the efficacy of bioremediation, both biostimulation and bioaugmentation with a lyophilized bacterial consortium (Rhodococcus erythropolis, Pseudomonas sp.), in accelerating hydrocarbon degradation. Metabarcoding analysis revealed a shift in microbial communities, with increased abundance of hydrocarbon-degraders (e.g. Alcanivorax, Thalassospira). Ninety-five hydrocarbonoclastic bacteria were isolated, including key groups from the enriched communities. The lyophilized bacteria added in bioaugmentation, enhanced the abundance of hydrocarbon-degraders over time and were recovered throughout time. Bioremediation treatments favoured biodegradation, achieving over 60 % removal of total petroleum hydrocarbons after 15 days, contrasting with natural attenuation where almost no TPH was removed. This work highlights the potential of bioremediation technologies to accelerate hydrocarbon-degrading activity, for oil spills inside ports.
https://www.sciencedirect.com/science/article/pii/S0025326X24004119
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Unveiling the culturable and non-culturable actinobacterial diversity in two macroalgae from the northern Portuguese coast
Mariana Girão, Diogo A. M. Alexandrino, Weiwei Cao, Isabel Costa, Zhongjun Jia and Maria F. Carvalho
Abstract: Actinomycetota, associated with macroalgae, remains one of the least explored marine niches. The secondary metabolism of Actinomycetota, the primary microbial source of compounds relevant to biotechnology, continues to drive research into the distribution, dynamics, and metabolome of these microorganisms. In this study, we employed a combination of traditional cultivation and metagenomic analysis to investigate the diversity of Actinomycetota in two native macroalgae species from the Portuguese coast. We obtained and taxonomically identified a collection of 380 strains, which were distributed across 12 orders, 15 families, and 25 genera affiliated with the Actinomycetia class, with Streptomyces making up approximately 60% of the composition. Metagenomic results revealed the presence of Actinomycetota in both Chondrus crispus and Codium tomentosum datasets, with relative abundances of 11% and 2%, respectively. This approach identified 12 orders, 16 families, and 17 genera affiliated with Actinomycetota, with minimal overlap with the cultivation results. Acidimicrobiales emerged as the dominant actinobacterial order in both macroalgae, although no strain affiliated with this taxonomic group was successfully isolated. Our findings suggest that macroalgae represent a hotspot for Actinomycetota. The synergistic use of both culture-dependent and independent approaches proved beneficial, enabling the identification and recovery of not only abundant but also rare taxonomic members.
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Cyanobacteria for Cardiomyocyte Protection against miocardial ischemia injury: a systematic review of animal and in vitro studies
Guilherme Scotta Hentschke, Vítor Scotta Hentschke, Fabiano Moraes Miguel
Abstract: Objective: To perform a systematic review on using Cyanobacteria for protecting the cardiac tissue against damage caused by ischemia. Methods: this review encompasses in vitro and controlled animal experimental
studies. Results: the results show that in general there are two types of interventions for treatment of ischemia and Ischemia/Reperfusion (IR) in cardiac tissue: (1) extracts treatments and (2) injection of Cyanobacteria in the damaged tissues. Extract treatments are based on the antioxidant potential of Cyanobacteria, and the studies focus mainly on Spirulina (Arthrospira platensis). The direct injection methods are based on the high capacity of these organisms to release oxygen during photosynthesis. Synechococcus elongatus is the Cyanobacteria species most commonly utilized in injections, either delivered independently or carried by hydrogels or nanoparticles. The direct Cyanobacteria injections are innovative techniques which can promote protection against apoptosis and have shown promising results, however, further research is necessary to refine the techniques and improve overall efficacy. Conclusion: the effects of these treatments were beneficial considering that the antioxidant effects of Cyanobacteria ameliorate blood biochemical markers and reduce damaged cardiac areas. The oxygen releasing of Cyanobacteria in the cardiac tissue also promoted recovery of cardiac tissue after ischemia or IR.https://revistaseletronicas.pucrs.br/index.php/scientiamedica/article/view/44970
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Anti-inflammatory activity of cyanobacteria pigment extracts: physiological radicals scavenging and modulation of iNOS and LOX activity
Lécia Rodrigues, Janaína Morone, Guilherme Scotta Hentschke, Vitor Vasconcelos and Graciliana Lopes
Abstract: Cyanobacteria are among the oldest organisms colonizing Earth. Their great biodiversity and ability to biosynthesize secondary metabolites through a variety of routes makes them attractive resources for biotechnological applications and drug discovery. In this pioneer study, four filamentous cyanobacteria (Cephalothrix lacustris LEGE 15493, Leptolyngbya boryana LEGE 15486, Nodosilinea nodulosa LEGE 06104 and Leptothoe sp. LEGE 11479) were explored for their anti-inflammatory potential in cell and cell-free in vitro bioassays, involving different inflammatory mediators and enzymes. Extracts of different polarities were sequentially prepared and chemically characterized for their content of phycobiliproteins (PBPs) and carotenoids. HPLC-PDA analysis of the acetone extracts revealed β-carotene to be the dominant carotenoid (18.4–44.3 mg/g) and zeaxanthin as the dominant xanthophyll (52.7–192.9 mg/g), with Leptothoe sp. LEGE 11479 and Nodosilinea nodulosa LEGE 06104, respectively, being the richest strains. The PBP profile was in accordance with the color presented by the aqueous extracts, with Leptolyngbya boryana LEGE 15486 being the richest in phycocyanin (204.5 μg/mg) and Leptothoe sp. LEGE 11479 the richest in phycoerythrin (78.5 μg/mg). Aqueous extracts were more effective in superoxide anion radical scavenging, while acetone ones were more effective in scavenging nitric oxide radical (●NO) and in inhibiting lipoxygenase. Acetone extracts also reduced ●NO production in lipopolysaccharide-stimulated RAW 264.7 macrophages, with the mechanistic study suggesting a downregulation of the inducible nitric oxide synthase expression. Nodosilinea nodulosa LEGE 06104 and Leptothoe sp. LEGE 11479 acetone extracts presented the lowest IC50 values for the mentioned assays, pointing them out as promising resources for the development of new multi-target anti-inflammatory therapies.
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Aquimarina aquimarini sp. nov. and Aquimarina spinulae sp. nov., novel bacterial species with versatile natural product biosynthesis potential isolated from marine sponges
Joana F. Couceiro, Matilde Marques, Sandra G. Silva, Tina Keller-Costa and Rodrigo Costa
Abstract: This study describes two Gram-negative, flexirubin-producing, biofilm-forming, motile-by-gliding and rod-shaped bacteria, isolated from the marine sponges Ircinia variabilis and Sarcotragus spinosulus collected off the coast of Algarve, Portugal. Both strains, designated Aq135T and Aq349T, were classified into the genus Aquimarina by means of 16S rRNA gene sequencing. We then performed phylogenetic, phylogenomic and biochemical analyses to determine whether these strains represent novel Aquimarina species. Whereas the closest 16S rRNA gene relatives to strain Aq135T were Aquimarina macrocephali JAMB N27T (97.8 %) and Aquimarina sediminis w01T (97.1 %), strain Aq349T was more closely related to Aquimarina megaterium XH134T (99.2 %) and Aquimarina atlantica 22II-S11-z7T (98.1 %). Both strains showed genome-wide average nucleotide identity scores below the species level cut-off (95 %) with all Aquimarina type strains with publicly available genomes, including their closest relatives. Digital DNA–DNA hybridization further suggested a novel species status for both strains since values lower than 70 % hybridization level with other Aquimarina type strains were obtained. Strains Aq135T and Aq349T grew from 4 to 30°C and with between 1–5 % (w/v) NaCl in marine broth. The most abundant fatty acids were iso-C17 : 03-OH and iso-C15 : 0 and the only respiratory quinone was MK-6. Strain Aq135T was catalase-positive and β-galactosidase-negative, while Aq349T was catalase-negative and β-galactosidase-positive. These strains hold unique sets of secondary metabolite biosynthetic gene clusters and are known to produce the peptide antibiotics aquimarins (Aq135T) and the trans-AT polyketide cuniculene (Aq349T), respectively. Based on the polyphasic approach employed in this study, we propose the novel species names Aquimarina aquimarini sp. nov. (type strain Aq135T=DSM 115833T=UCCCB 169T=ATCC TSD-360T) and Aquimarina spinulae sp. nov. (type strain Aq349T=DSM 115834T=UCCCB 170T=ATCC TSD-361T).
https://www.microbiologyresearch.org/content/journal/ijsem/10.1099/ijsem.0.006228
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Polyphasic description of Ciimarium marinum gen. et sp. nov. (Prochlorococcaceae, Synechococcales): a new picocyanobacterial taxon from the Portuguese coastal ecosystem
GUILHERME SCOTTA HENTSCHKE, JOÃO MORAIS, FLÁVIO OLIVEIRA, GRACILIANA LOPES, PEDRO N. LEÃO, ALDO BARREIRO, ÂNGELA PINHEIRO, SÉBASTIEN BRULE, VITOR M. VASCONCELOS
Abstract: In this paper, we describe Ciimarium marinum gen. et sp. nov. (Prochlorococcaceae, Synechococcales) based on 16S rRNA gene phylogenies, 16S-23S ITS secondary structures, ultrastructure (TEM), morphological, pigments and ecological data of “Synechococcus” sp. LEGE 11466. The strain was isolated from a sample collected at Leixões Harbour, Portugal (41°11’08.1”N 8°43’08.8”W) on September 26th, 2011, by scraping an epilithic biofilm under 10-13m depth, less than 1km offshore. Bayesian Inference and Maximum Likelihood phylogenies demonstrate that the Ciimarium sequence is placed in a monophyletic clade with strong phylogenetic support (BI=1, ML=100), within the Prochlorococcaceae cluster. The type strain LEGE 11466 is phylogenetically distant from other reference strains of Cyanobacteria and is grouped with Uncultured “Synechococcus” MLS1228cl3 , “Synechococcus” MLCB, “Cyanobium” ATX 6A2 ATX-6A2-C45 and “Synechococcus” MBIC10613.. The secondary structures of 16S-23S ITS corroborate with the separation of Ciimarium from all the Prochlorococcaceae genera. Also, they show that MLCB and ATX 6A2 ATX-6A2-C45 may be different species from the type LEGE 11466. The ultrastructure analysis shows parietal thylakoids, in agreement with the family description. Morphologically the genus is indistinguishable from other Prochlorococcaceae genera. The pigments analysis shows Zeaxanthin and β-carotene as the main pigments, and also a low concentration of phycocyanin. Finally, our phylogenies indicate that a revision of the Prochlorococcaceae family is necessary, as there are still many Synechococcus-like Cyanobacteria strains that should be described as new genera in the future.
https://phytotaxa.mapress.com/pt/article/view/phytotaxa.637.2.2
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First Polyphasic Study of Cheffia Reservoir (Algeria) Cyanobacteria Isolates Reveals Toxic Picocyanobacteria Genotype
Lamia Benredjem, João Morais, Guilherme Scotta Hentschke, Akila Abdi, Hajira Berredjem and Vitor Vasconcelos
Abstract: Monitoring water supply requires, among other quality indicators, the identification of the cyanobacteria community and taking into account their potential impact in terms of water quality. In this work, cyanobacteria strains were isolated from the Cheffia Reservoir and identified based on morphological features, the 16S rRNA gene, phylogenetic analysis, and toxin production by polymerase chain reaction PCR screening of the genes involved in the biosynthesis of cyanotoxins (mcyA, mcyE, sxtA, sxtG, sxtI, cyrJ, and anaC). Thirteen strains representing six different genera: Aphanothece, Microcystis, Geitlerinema, Lyngbya, Microcoleus, and Pseudanabaena were obtained. The results demonstrated the importance of morphological features in determining the genus or the species when incongruence between the morphological and phylogenetic analysis occurs and only the utility of the 16S rRNA gene in determining higher taxonomic levels. The phylogenetic analysis confirmed the polyphyly of cyanobacteria for the Microcystis and Oscillatoriales genera. Unexpectedly, Aphanothece sp. CR 11 had the genetic potential to produce microcystins. Our study gives new insight into species with picoplanktonic (or small) cell size and potentially toxic genotypes in this ecosystem. Thus, conventional water treatment methods in this ecosystem have to be adapted, indicating the requirement for pre-treatment methods that can effectively eliminate picocyanobacteria while preserving cell integrity to prevent toxin release.