ORCID Profile
0000-0003-2555-7967
Current Organisation
Universidade de São Paulo
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Publisher: Elsevier BV
Date: 07-2023
Publisher: Wiley
Date: 27-04-2023
Abstract: Mycosporine‐like amino acids (MAAs) are natural UV‐absorbing sunscreens that evolved in cyanobacteria and algae to palliate harmful effects from obligatory exposure to solar radiation. Multiple lines of evidence prove that in cyanobacteria all MAAs are derived from mycosporine‐glycine, which is typically modified by an ATP‐dependent ligase encoded by the gene mys D. The function of the mysD ligase has been experimentally described but haphazardly named based solely upon sequence similarity to the d ‐alanine‐ d ‐alanine ligase of bacterial peptidoglycan biosynthesis. Combining phylogeny and alpha‐fold tertiary protein structure prediction unambiguously distinguished mysD from d ‐alanine‐ d ‐alanine ligase. The renaming of mysD to mycosporine‐glycine‐amine ligase (MG‐amine ligase) using recognised enzymology rules of nomenclature is, therefore, proposed, and considers relaxed specificity for several different amino acid substrates. The evolutionary and ecological context of MG‐amine ligase catalysis merits wider appreciation especially when considering exploiting cyanobacteria for biotechnology, for ex le, producing mixtures of MAAs with enhanced optical or antioxidant properties.
Publisher: Wiley
Date: 20-06-2023
DOI: 10.1002/LOL2.10337
Abstract: Antarctica poses numerous challenges to life such as cold shock, low nutrient concentrations, and periodic desiccation over a wide range of extreme temperatures. Cyanobacteria survive this harsh environment having evolved adaptive metabolic plasticity to become the dominant primary producers. The type strain cyanobacterium Halotia branconii CENA392 was isolated from an Antarctic intertidal seashore. The complete circular genome of this strain is presented herein, which was assembled using long‐sequence reads. The genome encoded some stress‐related genes associated with low‐temperature adaptation and biosynthesis of mycosporine‐like amino acid (MAA) photoprotective compounds. Empirical experimentation demonstrated constitutive production of the MAA porphyra‐334 and total carotenoids without exposure to low temperatures or ultraviolet radiation stress. Phylogenetic analysis provided insights on taxonomic placement and evolutionary history of some annotated genes. These data exemplify the importance of generating complete quality genome sequences of microorganisms isolated from extreme intertidal environments, facilitating in‐depth evaluation of ecological and taxonomic inferences.
Publisher: Springer Science and Business Media LLC
Date: 06-2004
Publisher: MDPI AG
Date: 02-02-2023
DOI: 10.3390/MOLECULES28031420
Abstract: Cyanobacteria are oxygenic phototrophic prokaryotes that have evolved to produce ultraviolet-screening mycosporine-like amino acids (MAAs) to lessen harmful effects from obligatory exposure to solar UV radiation. The cyanobacterial MAA biosynthetic cluster is formed by a gene encoding 2-epi-5-epi-valiolone synthase (EVS) located immediately upstream from an O-methyltransferase (OMT) encoding gene, which together biosynthesize the expected MAA precursor 4-deoxygadusol. Accordingly, these genes are typically absent in non-producers. In this study, the relationship between gene cluster architecture and constitutive production of MAAs was evaluated in cyanobacteria isolated from various Brazilian biomes. Constitutive production of MAAs was only detected in strains where genes formed a co-linear cluster. Expectedly, this production was enhanced upon exposure of the strains to UV irradiance and by using distinct culture media. Constitutive production of MAAs was not detected in all other strains and, unexpectedly, production could not be induced by exposure to UV irradiation or changing growth media. Other photoprotection strategies which might be employed by these MAA non-producing strains are discussed. The evolutionary and ecological significance of gene order conservation warrants closer experimentation, which may provide a first insight into regulatory interactions of genes encoding enzymes for MAA biosynthesis.
Publisher: Wiley
Date: 30-08-2021
DOI: 10.1111/JPY.13200
Abstract: Free access databases of DNA sequences containing microbial genetic information have changed the way scientists look at the microbial world. Currently, the NCBI database includes about 516 distinct search results for Cyanobacterial genomes distributed in a taxonomy based on a polyphasic approach. While their classification and taxonomic relationships are widely used as is, recent proposals to alter their grouping include further exploring the relationship between Cyanobacteria and Melainabacteria. Nowadays, most cyanobacteria still are named under the Botanical Code however, there is a proposal made by the Genome Taxonomy Database (GTDB) to harmonize cyanobacteria nomenclature with the other bacteria, an initiative to standardize microbial taxonomy based on genome phylogeny, in order to contribute to an overall better phylogenetic resolution of microbiota. Furthermore, the assembly level of the genomes and their geographical origin demonstrates some trends of cyanobacteria genomics on the scientific community, such as low availability of complete genomes and underexplored s ling locations. By describing how available cyanobacterial genomes from free‐access databases fit within different taxonomic classifications, this mini‐review provides a holistic view of the current knowledge of cyanobacteria and indicates some steps towards improving our efforts to create a more cohesive and inclusive classifying system, which can be greatly improved by using large‐scale sequencing and metagenomic techniques.
Publisher: Elsevier BV
Date: 12-2005
DOI: 10.1016/J.WATRES.2005.10.002
Abstract: The ersity of the free-living nitrogen-fixing cyanobacterial community in the floodplain sediments along the Solimões and Amazon Rivers and some of their tributaries (Japurá, Negro and Madeira) was investigated. Five cyanobacterial genera were morphologically identified, four of which (Nostoc, Calothrix, Cylindrospermum and Fischerella) have not previously been isolated from the Brazilian Amazon floodplain. Nostoc strains were the most commonly found heterocyst-forming cyanobacteria. Five strains (N. muscorum CENA18 and CENA61, N. piscinale CENA21, Cylindrospermum sp. CENA33 and Fischerella sp. CENA19) were selected for growth measurement, ability to fix N2 and phylogenetic analysis, based on their widespread distribution and morphological distinction. Molecular analyses employing 16S rRNA sequences indicated that some of the isolates may represent novel cyanobacterial species. Dinitrogen fixed by these strains was measured indirectly as acetylene reduction activity and ranged from 11.5 to 22.2 nmol C2H4 microg Chl a(-1) h(-1). These results provide evidence of widespread and importance of nitrogen-fixing cyanobacteria as a source of N inputs in the Amazonian ecosystem.
No related grants have been discovered for Marli F. Fiore.