Publicações

  • 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 Cruza nd 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

  • Genome sequences of four novel Endozoicomonas strains associated with a tropical octocoral in a long-term aquarium facility

    Matilde Marques, Daniela M.G. da Silva, Elsa Santos, Núria Baylina, Raquel Peixoto, Nikos C. Kyrpides , Tanja Woyke , William B. Whitman , Tina Keller-Costa , Rodrigo Costa 

    Abstract: We report the genome sequences of four Endozoicomonas sp. strains isolated from the octocoral Litophyton maintained long term at an aquarium facility. Our analysis reveals the coding potential for versatile polysaccharide metabolism; Type II, III, IV, and VI secretion systems; and the biosynthesis of novel ribosomally synthesized and post-translationally modified peptides.

    https://doi.org/10.1128/mra.00872-24

  • Genome-based in silico assessment of biosynthetic gene clusters in Planctomycetota: Evidences of its wide divergent nature

    Rita Calisto, Ofélia Godinho, Damien P. Devos, Olga M. Lage

    Abstract: The biotechnological potential of Planctomycetota only recently started to be unveiled. 129 reference genomes and 5194 available genomes (4988 metagenome-assembled genomes (MAGs)) were analysed regarding the presence of Biosynthetic Gene Clusters (BGCs). By antiSMASH, 987 BGCs in the reference genomes and 22,841 BGCs in all the available genomes were detected. The classes Ca Uabimicrobiia, Ca Brocadiia and Planctomycetia had the higher number of BGC per genome, while Phycisphaerae had the lowest number. The most prevalent BGCs found in Planctomycetota reference genomes were terpenes, NRPS, type III PKS, type I PKS. As much as 88 % of the predicted regions had no similarity with known clusters in MIBiG database. This study strengthens the uniqueness of Planctomycetota for the isolation of new compounds and provide an overview of BGCs taxonomic distribution and of the type of predicted product. This outline allows the acceleration and focus of the research on drug discovery in Planctomycetota.

    https://doi.org/10.1016/j.ygeno.2024.110965

  • Genome sequence of the marine alphaproteobacterium Lentilitoribacter sp. EG35 isolated from the temperate octocoral Eunicella gazella

    Tina Keller-Costa, Selene Madureira, Ana S. Fernandes, Lydia Kozma, Jorge M.S. Gonçalves, Cristina Barroso, Conceição Egas, Rodrigo Costa

    Abstract: We report the genome sequence of Lentilitoribacter sp. strain EG35 isolated from the octocoral Eunicella gazella sampled off the coast of Portugal. We reveal the coding potential for the biosynthesis of polyhydroxyalkanoates — biodegradable polyesters that may serve bioplastics production, diverse homoserine lactone-like communication signals, and four putatively novel natural products.

    https://doi.org/10.1128/mra.00872-24

  • Carotenoids from cyanobacteria modulate iNOS and inhibit the production of inflammatory mediators: Promising agents for the treatment of inflammatory conditions

    Janaína Morone, Guilherme Hentschke, Eugénia Pinto, João Morais, Pedro Cruz, Vitor Vasconcelos, Rosário Martins, Graciliana Lopes

    Abstract: Cyanobacteria are green multiproduct refineries of increasing interest for different industrial prospects. In this work, eleven cyanobacteria strains isolated from the Cape Verde archipelago were explored for their biotechnological applications in the field of inflammation. A biorefinery approach was employed to produce carotenoidtargeted extracts, further profiled by HPLC-PDA and explored for their ability to i) scavenge important physiological free radicals of oxygen (superoxide anion radical, O2•-) and nitrogen (nitric oxide, •NO) involved in the
    inflammatory process ii) slow-down post-inflammatory hyperpigmentation and iii) modulate the activity of inflammatory cytokine-producing enzymes, in enzymatic and cell systems comprising RAW 264.7 cells. The studied strains turned out to be important carotenoid producers (70.47–186.71 μg mg􀀀 1dry extract), mainly represented by β-carotene and zeaxanthin. The targeted-extracts stood-out for their potential to slow-down the inflammatory process through a multitarget approach: scavenging •NO and O2•-, reducing inflammatory cytokines
    production through lipoxygenase inhibition, and modulating the inducible nitric oxide synthase in LPSstimulated RAW 264.7 cells, with strains of the order Nodosilineales revealing to be worth of further biotechnological exploitation.

    https://doi.org/10.1016/j.algal.2024.103729

  • Cellulamides: A New Family of Marine-Sourced Linear Peptides from the Underexplored Cellulosimicrobium Genus

    Mariana Girão, José Murillo-Alba, Jesús Martín, Ignacio Pérez-Victoria, Ricardo B. Leite, Ralph Urbatzka , Pedro N. Leão, Maria F. Carvalho and Fernando Reyes

    Abstract: Bioprospecting the secondary metabolism of underexplored Actinomycetota taxa is a prolific route to uncover novel chemistry. In this work, we report the isolation, structure elucidation, and bioactivity screening of cellulamides A and B (1 and 2), two novel linear peptides obtained from the culture of the macroalga-associated Cellulosimicrobium funkei CT-R177. The host of this microorganism, the Chlorophyta Codium tomentosum, was collected in the northern Portuguese coast and, in the scope of a bioprospecting study focused on its associated actinobacterial community, strain CT-R177 was isolated, taxonomically identified, and screened for the production of antimicrobial and anticancer compounds. Dereplication of a crude extract of this strain using LC-HRMS(/MS) analysis unveiled a putative novel natural product, cellulamide A (1), that was isolated following mass spectrometry-guided fractionation. An additional analog, cellulamide B (2) was obtained during the chromatographic process and chemically characterized. The chemical structures of the novel linear peptides, including their absolute configurations, were elucidated using a combination of HRMS, 1D/2D NMR spectroscopy, and Marfey’s analysis. Cellulamide A (1) was subjected to a set of bioactivity screenings, but no significant biological activity was observed. The cellulamides represent the first family of natural products reported from the Actinomycetota genus Cellulosimicrobium, showcasing not only the potential of less-explored taxa but also of host-associated marine strains for novel chemistry discovery.

    https://doi.org/10.3390/md22060268

  • The extremophile Eurychoronema bolivianum gen. et sp. nov. (Nodosilineales, Cyanobacteria) and Leptolyngbya aquatica comb. nov

    Guilherme Scotta Hentschke, Jimmy Casto Ciancas Jiménez, Claudia Hoepfner, Daniel Guzmán, Maria João Mesquita & Vitor Vasconcelos

    Abstract: Extreme environments exhibit conditions that are beyond the tolerances of most species. They are characterized by extremes in temperature, pressure, gas concentrations, salinity, radiation, pH or water availability. Despite their harsh conditions, extreme environments are a rich source for discovering new cyanobacterial taxa. The Bolivian Altiplano is an extreme environment characterized by sub-freezing temperatures, high salinity and some of the lowest precipitation rates on Earth. From this environment,
    the homocytous filamentous strain LEGE 231228 was isolated. Our 16S rRNA gene phylogenetic analyses showed that this strain was positioned within a clade, sister to a cluster containing Toxifilum and Sodaleptolyngbya strains, in the Nodosilineales clade. The 16S rRNA gene identity analysis revealed that when comparing LEGE 231228 with Toxifilum and Sodaleptolyngbya, the maximum values reached only 94.3% and 93.6%, respectively. Morphologically, LEGE 231228 differed from Sodaleptolyngbya and Toxifilum primarily by forming fascicles and having sheaths that sometimes envelop more than one trichome. Based on these findings, we propose Eurychoronema bolivianum gen. & sp. nov. Additionally, the 16S rRNA gene phylogenies and identity, alongside morphological and 16S-23S ITS analyses permitted us to transfer the Leptolyngbyaceae genus Radiculonema into Leptolyngbya. Radiculonema was nested within the Leptolyngbya clade and both genera shared 95.1% 16S rRNA identity. There was also no morphological difference between these two genera. We also demonstrate that conclusions based on secondary structures of the 16S-23S ITS region alone can be interpreted in different ways.

    https://doi.org/10.1080/00318884.2024.2412366

  • Description of Pegethrix niliensis sp. nov., a Novel Cyanobacterium from the Nile River Basin, Egypt: A Polyphasic Analysis and Comparative Study of Related Genera in the Oculatellales Order

    Guilherme Scotta Hentschke, Zakaria Mohamed, Alexandre Campos and Vitor M. Vasconcelos

    Abstract: In this paper, we examine the filamentous cyanobacterial strain NILCB16 and describe it as a new species within the genus Pegethrix. The original population was sampled from a mat growing in an irrigation canal in the Nile River, Egypt. Initially classified under Plectonema or Planktolyngbya, the strain is a potential producer of the toxins microcystin and β-N-Methylamino-L-Alanine (BMAA). Additionally, we reviewed the taxonomic relationships between the Oculatellales genera. To describe the new species, we conducted a polyphasic study, encompassing 16S rRNA gene phylogenetic analyses performed using both Maximum Likelihood and Bayesian methods, sequence identity (p-distance) analysis, 16S-23S ITS secondary structures, and morphological and habitat comparisons. The phylogenetic analysis revealed that strain NILCB16 clustered within the Pegethrix clade with strong phylogenetic support, but in a distinct position from other species in the genus. The strain shared a maximum 16S rRNA gene identity of 97.3% with P. qiandaoensis and 96.1% with the type species, P. bostrychoides. Morphologically, NILCB16 can be differentiated from other species in the genus by its lack of false branching. Our phylogenetic analyses also show that Pegethrix, Cartusia, Elainella, and Maricoleus are clustered with strong phylogenetic support. They exhibit high 16S rRNA gene identity and are morphologically indistinguishable, suggesting they could potentially be merged into a single genus in the future.

    https://doi.org/10.3390/toxins16100451