Biobanco Azul Português

Category: Artigos Científicos

  • Decoding Lusichelins A-E: An In-Depth Look at the Metallophores of Lusitaniella coriacea LEGE 07167 – Structure, Production, and Functionality

    Maria Lígia Sousa, Leonor Ferreira, Dora Ferreira, Abel M. Forero , Raquel Castelo-Branco , Nikoletta Szemerédi , Gabriella Spengler , Jaime Rodríguez Author , Carlos Jiménez , Pedro N. Leão , Vitor Vasconcelos, Mariana Reis

     

    Abstract: Essential trace metals are vital for cellular processes such as respiration, DNA replication, and photosynthesis. Cyanobacteria must tightly regulate metal homeostasis to prevent deficiency or toxicity, yet their metallophores remain overlooked. Here, we report lusichelins A-E (1-5), new metallophores isolated from the marine cyanobacterium Lusitaniella coriacea LEGE 07167. Their structures and configurational assignments were determined using NMR, mass spectrometry, TD-DFT calculations, and retrobiosynthetic insights. Lusichelins feature a unique structural arrangement with thiazoline/thiazole rings connected by a vinyl group, an aliphatic carbon chain, or directly, enabling potential for hexadentate metal coordination. Genomic analysis identified a hybrid PKS/NRPS biosynthetic gene cluster consistent with the structure of lusichelins and bearing traits characterisitic of metallophore biosynthesis. Notably, lusichelin production was influenced by salt composition in the culture medium rather than iron availability, suggesting an atypical regulatory mechanism. Functionally, lusichelins acted as copper detoxifiers, and lusichelin B (2) exhibited cytotoxicity against colon carcinoma cells while reversing multidrug resistance via ABCB1 efflux pump modulation. These findings expand the understanding of cyanobacterial metallophores in microbial metal homeostatis and highlight their potential in biological applications

    https://doi.org/10.26434/chemrxiv-2025-63fgd

  • Diversity of Cyanobacterial Genera Present in Cabo Verde Marine Environments and the Description of Gibliniella gelatinosa sp. nov

    João Morais, Pedro Cruz, Guilherme Scotta Hentschke, Bruna Silva, Flavio Oliveira, Jorge Neves, Raquel Silva, Vitor Ramos, Pedro N. Leão, Vitor Vasconcelos

     

    Abstract: The aim of this study was to document the biodiversity of cyanobacteria genera isolated from intertidal and subtidal zones in Cabo Verde. The identification of the strains was conducted using a polyphasic study, comprising 16S rRNA gene maximum likelihood and Bayesian inference phylogeny, 16S rRNA identity (p-distance), 16S–23S ITS secondary structure, morphological, and habitat analyses. A total of 51 strains were isolated by micromanipulation and by streaking biomass onto Petri dishes with a solid medium. Seventeen strains were identified as belonging to the Salileptolyngbya genus and five to Leptothoe; sixteen strains were distributed across twelve genera. Thirteen strains were grouped into eight distinct clades, but could not be assigned to any cyanobacterial genus, indicating that they could be described as new cyanobacterial genera in the future. The phylogenies also exhibited isolates LEGE 181157, LEGE 181224, and LEGE 181227 clustered with Gibliniella, but in a separate clade from the G. alaskensis type. The 16S rRNA gene identity values among these new isolates and G. alaskensis ranged from 94.4% to 95.5%. The 16S–23S ITS dissimilarity between LEGE 181224 and G. alaskensis was 9.4%. Morphologically, these three LEGE strains differ from G. alaskensis in that they have trichomes that are never coiled and have diffluent mucilaginous envelopes, whereas G. alaskensis has coiled trichomes with firm sheaths. Based on these strains, we describe here a new species of Gibliniella.

    https://doi.org/10.3390/plants14030299

  • Actinomycetota From Macroalgae as Rich Source for Natural Products Discovery Revealed Through Culture-Dependent and -Independent Approaches

    Mariana Girão, Adriana Rego, Ana C. Fonseca, Weiwei Cao, Zhongjun Jia, Ralph Urbatzka, Pedro N. Leão, Maria F. Carvalho

     

    Abstract: Actinomycetota are unrivalled producers of bioactive natural products, with strains living in association with macroalgae representing a prolific—yet largely unexplored—source of specialised chemicals. In this work, we have investigated the bioactive potential of Actinomycetota from macroalgae through culture-dependent and -independent approaches. A bioprospecting pipeline was applied to a collection of 380 actinobacterial strains, recovered from two macroalgae species collected in the Portuguese northern shore—Codium tomentosum and Chondrus crispus—in order to explore their ability to produce antibacterial, antifungal, anticancer and lipid-reducing compounds. Around 43% of the crude extracts showed activity in at least one of the screenings performed: 111 presented antimicrobial activity at 1mg/mL, 83 significantly decreased cancer cells viability at 15μg/mL and 5 reduced lipid content in zebrafish >60% at 15 ug/mL. Dereplication of active extracts unveiled the presence of compounds that could explain most of the recorded results, but also unknown molecules in the metabolome of several strains, highlighting the opportunity for discovery. The bioactive potential of the actinobacterial community from the same macroalgae specimens, which served as the source for the aforementioned Actinomycetota collection, was also explored through metagenomics analysis, allowing to obtain a broader picture of its functional diversity and novelty. A total of 133 biosynthetic gene clusters recovered from metagenomic contigs and metagenome assembled genomes (MAGs). These were grouped into 91 gene cluster families, 83 of which shared less than 30% of similarity to database entries. Our findings provided by culture-dependent and -independent approaches underscore the potential held by actinomycetes from macroalgae as reservoirs for novel bioactive natural products.

    https://doi.org/10.1111/1751-7915.70058

  • Living Coral Displays, Research Laboratories, and Biobanks as Important Reservoirs of Chemodiversity with Potential for Biodiscovery

    Ricardo Calado, Miguel C. Leal, Ruben X. G. Silva, Mara Borba, António Ferro, Mariana Almeida, Diana Madeira and Helena Vieira

     

    Abstract: Over the last decades, bioprospecting of tropical corals has revealed numerous bioactive compounds with potential for biotechnological applications. However, this search involves sampling in natural reefs, and this is currently hampered by multiple ethical and technological constraints. Living coral displays, research laboratories, and biobanks currently offer an opportunity to continue to unravel coral chemodiversity, acting as “Noah’s Arks” that may continue to support the bioprospecting of molecules of interest. This issue is even more relevant if one considers that tropical coral reefs currently face unprecedent threats and irreversible losses that may impair the biodiscovery of molecules with potential for new products, processes, and services. Living coral displays provide controlled environments for studying corals and producing both known and new metabolites under varied conditions, and they are not prone to common bottlenecks associated with bioprospecting in natural coral reefs, such as loss of the source and replicability. Research laboratories may focus on a particular coral species or bioactive compound using corals that were cultured ex situ, although they may differ from wild conspecifics in metabolite production both in quantitative and qualitative terms. Biobanks collect and preserve coral specimens, tissues, cells, and/or information (e.g., genes, associated microorganisms), which offers a plethora of data to support the study of bioactive compounds’ mode of action without having to cope with issues related to access, standardization, and regulatory compliance. Bioprospecting in these settings faces several challenges and opportunities. On one hand, it is difficult to ensure the complexity of highly biodiverse ecosystems that shape the production and chemodiversity of corals. On the other hand, it is possible to maximize biomass production and fine tune the synthesis of metabolites of interest under highly controlled environments. Collaborative efforts are needed to overcome barriers and foster opportunities to fully harness the chemodiversity of tropical corals before in-depth knowledge of this pool of metabolites is irreversibly lost due to tropical coral reefs’ degradation.

    https://doi.org/10.3390/md23020089

  • Culturable Yeast Diversity Associated with Industrial Cultures of the Microalga Microchloropsis gaditana and Their Ability to Produce Lipids and Biosurfactants

    Madalena Matos, Mónica A. Fernandes, Inês Costa, Natacha Coelho, Tamára F. Santos, Veronica Rossetto, João Varela and Isabel Sá-Correia

     

    Abstract: The marine oleaginous microalga Microchloropsis gaditana (formerly Nannochloropsis gaditana) exhibits a high capacity to thrive in a broad range of environmental conditions, being predominantly utilized as feed in aquaculture. This article reports the characterization of the culturable yeast population present during the scale-up process of M. gaditana cultivation at Necton S.A. facilities, from 5 L flasks until tubular photobioreactors. The 146 yeast isolates obtained, molecularly identified based on D1/D2 and ITS nucleotide sequences, belong to the species Rhodotorula diobovata, R. mucilaginosa, R. taiwanensis, R. sphaerocarpa, Vishniacozyma carnescens, Moesziomyces aphidis, and Meyerozyma guilliermondii. The yeast abundance was found to increase throughout upscaling stages. The yeast populations isolated from microalgal cultures and water samples share phylogenetically close isolates, indicating a possible common source. The impressive high percentage of red yeasts isolated (90%) is consistent with the recognized role of carotenoid pigments in yeast photoprotection. Sixty yeast isolates were tested for lipid (Nile Red staining) and biosurfactant (oil drop dispersion and emulsification index) production. Results revealed that these capacities are common features. Microbial lipids and biosurfactants have promising biotechnological applications. Moreover, biosurfactants can fulfill various physiological roles and provide advantages in natural environments contributing to the promising use of yeasts as probiotics in microalgae production.

    https://doi.org/10.3390/jof11030228

  • Actinomycetota Isolated from the sponge Hymeniacidon perlevis as a Source of Novel Compounds with Pharmacological Applications: Diversity, Bioactivity Screening, and Metabolomic Analysis

    Ana C Fonseca, Inês Ribeiro, Mariana Girão, Ana Regueiras, Ralph Urbatzka , Pedro Leão , Maria F Carvalho 

     

    Abstract: To combat health conditions, such as multi-resistant bacterial infections, cancer, and metabolic diseases, new drugs need to be urgently found and, in this respect, marine Actinomycetota have a high potential to produce secondary metabolites with pharmacological importance. We aimed to study the cultivable Actinomycetota community associated with a marine sponge from the Portuguese coast, Hymeniacidon perlevis, and investigate the potential of the retrieved isolates to produce compounds with antimicrobial, anticancer and anti-obesity properties.

    https://doi.org/10.1093/jambio/lxaf044

  • Endozoicomonas lisbonensis sp. nov., a novel marine bacterium isolated from the soft coral Litophyton sp. at Oceanário de Lisboa in Portugal

    Daniela M. G. da Silva, Matilde Marques, Joana F. Couceiro, Elsa Santos, Núria Baylina, Rodrigo Costa and Tina Keller-Costa

     

    Abstract: This study describes a Gram-stain-negative, rod-shaped, facultatively anaerobic bacterial species isolated from the octocoral Litophyton sp. inhabiting the live coral aquarium at Oceanário de Lisboa in Portugal. Four strains, NE35, NE40T, NE41 and NE43, were classified into the genus Endozoicomonas by means of 16S rRNA gene and whole-genome sequence homologies. We then performed phylogenetic, phylogenomic and biochemical analyses to examine their novel species status within the Endozoicomonas genus, based on comparisons with the designated novel type strain NE40T. The closest 16S rRNA gene relatives to strain NE40T are Endozoicomonas montiporae CL-33T (98.2%), Endozoicomonas euniceicola EF212T (97.6%) and Endozoicomonas gorgoniicola PS125T (97.2%). The four strains show genome-wide average nucleotide identity scores above the species level cut-off (95%) with one another and below the cut-off with all Endozoicomonas type strains with publicly available genomes. Digital DNA–DNA hybridization further supported the classification of the strains as a novel species, showing values below 70% when compared with other Endozoicomonas type strains. The DNA G+C content of NE40T was 49.0 mol%, and its genome size was 5.45 Mb. Strain NE40T grows from 15 to 37 °C, with 1–5% (w/v) NaCl, and between pH 6.0 and 8.0 in marine broth and shows optimal growth at 28–32 °C, 2–3% NaCl and pH 7.0–8.0. The predominant cellular fatty acids are summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c), summed feature 8 (C18 : 1 ω6c and/or C18 : 1 ω7c), C16 :0 and C14 :0. Strain NE40T presents oxidase, catalase and β-galactosidase activities and can reduce nitrates to nitrites and degrade cellulose, chitin, agarose and xylan. Based on the polyphasic approach employed in this study, we propose the novel species name Endozoicomonas lisbonensis sp. nov. (type strain NE40T=DSM 118084T=UCCCB 212T).

    https://doi.org/10.1099/ijsem.0.006696

  • Beyond Restoration: Coral Microbiome Biotechnology

    Joana F. Couceiro, Rodrigo Costa & Tina Keller-Costa

     

    Abstract: Coral-associated microorganisms harbour an impressive and diverse secondary metabolite biosynthesis capacity with novel bioactive compounds being reported every year. The need of the coral holobiont to combat predation, overgrowth, and fouling presumably led to the ability of coral-associated microbes to produce different classes of compounds with a broad spectrum of activities. Although the precise ecological functions of most compounds from coral-associated microbes remain unknown or unproven, the biotechnological applications and prospective benefits of their exploitation are at hand. Bioactivities of pharmaceutical and industrial interest of coral symbiont-derived compounds include antitumoral, antibacterial, antifungal, antifouling, anti-inflammatory, and antidiabetic properties among many others, indicating vast potential for blue biotechnology and blue pharma. Moreover, coral-derived microorganisms often produce enzymes which can be employed in bioindustrial processes or for bioremediation purposes, for instance, in oil spills. This chapter reviews new natural products from coral symbionts reported between the years 2018 and 2022, highlighting the versatility and economic potential of this unique chemical reservoir. More than 385 novel compounds were described from coral-associated microbes in the past 5 years, 75% of them from octocoral (Octocorallia) symbionts. Over 87% of the compounds derive from coral-associated fungi of the Ascomycota phylum while only about 12% come from bacterial associates in the phyla Actinomycetota, Pseudomonadota, Bacillota and Cyanobacteria. Terpenes, alkaloids, peptides, and polyketides are the most prominent compound classes, many of which show anticancer, antibacterial, antifungal and antidiabetic activities. Despite the wide compound range described in coral-associated microorganisms, this chapter unveils that most of the lately applied research efforts target only certain microbial groups, such as actinomycetes and fungi, or specific geographical locations (e.g., South China Sea) and coral species. It reveals corals as a warehouses of microbes with bioactive potential similar to what is known from marine sponges. This largely untapped reservoir of novel natural products from coral-associated microbes is yet to be unlocked in future biodiscovery programs. We thus call on the scientific community to expand the scope of their coming research, directing it towards less explored groups such as cold-water corals and non-actinomycete bacterial symbionts. We also suggest a stronger integration of metagenomics libraries, synthetic biology, and heterologous expression approaches to access the chemical space of unculturable coral symbionts, as well as, the inclusion of new cultivation strategies, such as the iChip, for a more comprehensive, polyphasic approach.

    https://doi.org/10.1007/978-3-031-76692-3_15

  • The Description of the Extremophile Reticulonema bolivianum gen. et sp. nov. (Microcoleaceae, Cyanobacteria) and the Review of the Phylogenetic Status of the Genus Capilliphycus Based on the 16S rRNA Gene

    Guilherme Scotta Hentschke, Claudia Hoepfner, Daniel Guzmán and Vitor M. Vasconcelos

     

    Abstract: This article describes a new genus and species of cyanobacteria isolated from Laguna Pastos Grandes in the Bolivian Altiplano. This discovery marks the first described species of this phylum from this extreme environment. Additionally, the phylogenetic status of the genus Capilliphycus is reassessed. The analyses are based on 16S rRNA gene maximum likelihood and Bayesian phylogenies, identity (p-distance), morphology and habitat comparisons. The new genus is a Lyngbya-like type from a mat at the margin of a brackish–alkaline lake with borax. It is phylogenetically close to Dapis, Tenebriella and Okeania, but compared to these genera, the maximum 16S rRNA gene identity values reached only 90.9%, 91.1% and 92.5%, respectively. The genus Capilliphycus was found to be polyphyletic. The type species Capilliphycus salinus is clustered with C. guerandensis. However, “C. tropicalis” and “C. flaviceps” form a distinct clade, distant from the Capilliphycus type species. Between the two “Capilliphycus” clades, Sirenicapillaria and Limnoraphis are found.

    https://doi.org/10.3390/plants14030310

  • Taxonomic updates in the family Leptolyngbyaceae (Leptolyngbyales,Cyanobacteria): the description of Pseudoleptolyngbya gen. nov, Leptolyngbyopsisgen. nov., and the replacement of Arthronema

    Guilherme Scotta Hentschke, João Morais, Flavio Luis de Oliveira, Raquel Silva, Pedro Cruz, Vitor Vasconcelos

     

    Abstract: In this paper, we used the polyphasic approach combining 16S rRNA gene phylogenies, identity (p-distance), 16S-23S ITSsecondary structures, and morphological and habitat analyses to describe two new genera of Leptolyngbyaceae,Pseudoleptolynbgya G.S. Hentschke gen. nov. (based on LEGE 16533 and LEGE 16651) and Leptolyngbyopsis G.S.Hentschke gen. nov. (based on LEGE 16524). These strains were sampled from freshwater environments at Figueira daFoz, Monchique and Coimbra, Portugal. Both genera are morphologically and ecologically identical to Leptolyngbya andcan only be distinguished from it by molecular analyses. Based on morphological and ITS secondary structure analyses wedescribe two species of Pseudoleptolyngbya, P. figueirensis and P. monchiquensis. P. figueirensis differs fromP. monchiquensis by the denser arrangement of the trichomes, the presence of firm sheaths, the common formation ofshorter trichomes (up to 30 cells), and the olive or yellowish-green cell content, which is darker in P. monchiquensis.Moreover, the macroscopic appearance of P. figueirensis is a dense brownish mat, while P. monchiquensis is less dense andreddish. 16S rRNA gene sequences of Arthronema africanum CCALA020 are > 99% identical to Leptolyngbya boryanaPCC6306, so we transfer A. africanum to Leptolyngbya, as L. africanoidea.

    https://doi.org/10.1080/09670262.2024.2404887