Jéssica Aparecida Silva Moretto

The cyanobacterial genus Lyngbya was once thought to be a cosmopolitan genus, inhabiting nearly every biome across the globe. However, utilization of genetic, and more recently genomic, sequencing has revealed that this morphologically homogenous taxon in fact comprises distinct evolutionary clades, leading to the plethora of newly described Cyanobacterial genera split from Lyngbya . Despite this, no comparisons can be made to L. confervoides , and thus begging the question: who is Lyngbya ? To answer this, we collected cyanobacterial tufts from intertidal pools in Cádiz, Spain, in line with the original descriptions of L. confervoides from Agardh and Gomont. Morphological and genetic characterization were conducted on two Lyngbya ‐like strains isolated from the type location. We identified strain BLCC‐M349 to match the original description and iconograph, thereby designating it as the epitype of L. confervoides with BLCC‐M349 serving as the reference strain. The descriptions of both Lyngbya and L. confervoides are emended and sequences of the 16S rRNA gene, the 16S‐23S ITS rRNA region, and the genome are provided. Additionally, we describe a novel species of Okeania as well as synonymize select species of Capilliphycus to Lyngbya .

Harmful cyanobacterial blooms pose risks to the environment, humans, and animals. Rapid identification of these microorganisms is essential but still relies on costly and time-consuming techniques. This study evaluates the potential of attenuated total reflectance infrared spectroscopy (ATR-FTIR) combined with chemometrics, supported by molecular methods, to detect potentially harmful cyanobacteria. Samples were collected from 14 sites in the Rio Pardo Valley, RS, Brazil, with limnological parameters measured. Spectra (4000–650 cm⁻¹) in triplicate, and 16S rRNA metabarcoding was performed using Dada2, Phyloseq, and the CyanoSeq database. PCA and OPLS analyses were applied to integrate spectral, taxonomic, and environmental data. Twelve cyanobacterial genera were identified. Sphaerospermopsis (Zapomelová et al., 2010) dominated SP14, associated with aluminum, iron, and nitrogen levels. Dolichospermum ((Bornet & Flahault) P. Wacklin, L. Hoffmann & Komárek, 2009) and Wollea (Bornet & Flahault, 1886) correlated with phosphorus and sodium. Planktothricoides (S. Suda & M. Watanabe, 2002) showed 95.15% abundance at SP01. PC1×PC2 plots revealed location-based clustering of spectral data. ATR/OPLS models showed strong correlations with relative abundances derived from metabarcoding data, with RMSECV values from 1.3×10⁻⁵ to 5.3×10⁻⁴ and R² > 0.99. These results support ATR-FTIR and chemometrics as a promising exploratory approach for the assessment of cyanobacterial community composition in freshwater systems.

Dapis , along with other benthic cyanobacteria, forms large extensive proliferations (i.e., blooms, mats) that cover sand and seagrass beds across the coasts of Florida, United States. As these benthic cyanobacteria become more prevalent, especially in areas like the Indian River Lagoon (IRL), Sarasota Bay, Lemon Bay, Tampa Bay, and the Florida Keys, it is necessary to understand their diversity. To explore the diversity and identify the causative species of these nuisance marine benthic mats, growing and rafting mats were sampled. Three cyanobacterial isolates from marine mats across Florida were characterized and revealed to represent three novel species of Dapis , but with differing morphological features than those of previously described species. With the support of 16S rRNA gene sequence phylogeny, morphological evaluations, 16S–23S ITS rRNA region pairwise distances, and phylogenomic analyses, we have presented three novel species of Dapis . We have also provided taxonomically validated sets of Dapis genomes from several species.

Stormwater ponds (SWPs) host distinct microbial communities. Here, we use 16S rRNA metabarcoding to characterize bacterial communities in four SWPs in South Florida, USA. A total of 37,002 amplicon sequence variants were identified, Cyanophyceae was the dominant class in pond A, while Gammaproteobacteria dominated the other ponds.

Cyanobacteria exhibit a vast diversity from polar to tropical environments. Though much work has been done on elucidating their biodiversity, knowledge on the occurrence, diversity and toxicity of benthic cyanobacteria is limited when compared to the planktonic forms. Integrating molecular techniques with ecological and morphological analyses has become essential in untangling cyanobacterial diversity, particularly for benthic taxa such as the cryptic “Lyngbya.” Molecular markers such as the 16S rRNA gene and whole genome sequencing have significantly improved the taxonomy of cyanobacteria. Building on these advancements, this study characterizes benthic cyanobacterial isolates from various locations in Florida, USA, and Orange Walk, Belize, resulting in the identification of a novel genus, Floridanema, and four new species (F. aerugineum, F. evergladense, F. flaviceps, and F. fluviatile). This new genus commonly occurs in canals, ponds, lakes and rivers. By integrating ecological, morphological, and genomic analyses, this study provides support for the family Aerosakkonemataceae and the establishment of the order Aerosakkonematales. The LC–MS data revealed that Floridanema strains do not produce microcystins, nodularin‐R, or anabaenopeptins.

Lake Mattamuskeet, the largest lake in North Carolina, USA, has undergone decades‐long eutrophication causing reduced water quality and promoting cyanobacterial blooms that may produce toxins. It is therefore necessary to evaluate the cyanobacterial diversity of the lake and their toxigenic potential. We present draft genomes of Microcystis, Pelatocladus, Raphidiopsis, and Umezakia strains isolated from Lake Mattamuskeet. The whole‐genome shotgun projects for Umezakia ovalisporum BLCC‐F208, Microcystis sp. BLCC‐F209, Microcystis sp. BLCC‐F210, Pelatocladus sp. BLCC‐F211, U. ovalisporum BLCC‐F215, and Raphidiopsis BLCC‐F218 have been deposited in GenBank under accession numbers JBHFLK000000000, JBHFLL000000000, CP169647, JBHFLM000000000, JBHFLN000000000, and JBHFLO000000000, respectively. Based on the genomic analysis, several biosynthetic gene clusters (BCGs) with varying degrees of similarity to known toxic and bioactive compound gene clusters were identified across the different cyanobacterial strains.

Background: Cyanobacteria blooms have become a major environmental problem and concern because of secondary metabolites produced by cyanobacteria released into the water. Cyanobacteria produce volatile organic compounds (VOCs), such as the compounds β-cyclocitral and β-ionone, which comprise odors, off-flavors, defense compounds, as well as growth regulators. Therefore, the general objective of this work was to evaluate the VOCs produced by two strains of Microcystis aeruginosa, differing in their ability to produce microcystins (LTPNA 01—non-producing and LTPNA 08—toxin-producing). The analysis of VOC production was carried out in (1) normal culture conditions, (2) under different light intensities (LI), and (3) after the external application of β-ionone in both cultures. Results: The results showed that β-cyclocitral and β-ionone are produced in all growth phases of LTPNA 01 and LTPNA 08. Both strains were producers of β-cyclocitral and β-ionone in normal culture conditions. It was observed that the β-cyclocitral concentration was higher than β-ionone in all light intensities investigated in this study. Additionally, the strain LTPNA 01 produced more β-cyclocitral than LTPNA 08 at almost all times and LIs analyzed. However, the strain LTPNA 08 produced more β-ionone, mainly at the initial times. In addition, the experiment results with the external addition of β-ionone in the cultures showed that the strain LTPNA 01 produced more β-cyclocitral in control conditions than in treatment. Nonetheless, β-ionone production was higher in treatment conditions in LTPNA 08, indicating that the addition of β-ionone may favor the production of these compounds and inhibit the production of β-cyclocitral. Conclusion: Our results showed that some abiotic factors, such as different light intensities and external application of β-ionone, can be triggers that lead to the production of VOCs.

(1) Background: The extraction of fatty acids from microalgae and cyanobacteria is mostly performed with organic solvents and laborious procedures. Microwave-assisted extraction (MAE) can be a more effective and environmentally friendly process than traditional extraction (TE), which uses a large volume of solvent and conduction heating. Freshwater phytoplankton inhabits diverse aquatic environments and is a promising source of fatty acids and green precursors in the synthesis of biofuel, including cyanobacterial biomass. Therefore, the aim of this study was to investigate the potential of MAE to extract fatty acids from a Chlorella sp. microalga and two cyanobacteria, namely, Arthrospira sp. and Sphaerospermopsis torques-reginae, for biodiesel production. For this purpose, the lipid content and fatty acid profile of these strains were compared after treating biomass with the two extraction methods. (2) Methods: MAE and TE were used as extraction procedures; gas chromatography–mass spectrometry was used to assess the fatty acid profiles, and X-ray spectroscopy was used to analyze biomass. (3) Results: Although the fatty acid profile of the oil obtained by TE showed higher concentrations of fatty acids, the MAE method was able to extract more types of fatty acids. The variety of fatty acids extracted by the MAE, especially those with unsaturated chains, allowed for better quality biodiesel, presenting advantages over previous methods and studies. According to the analyses, essential fatty acids 16:0, 16:1, and 18:2 were found to be abundant in both cyanobacterial strains and in microalga, showing potential for biofuel production. Additionally, metal composition was determined as its content may indicate potential pro-oxidant influence in biofuel production. (4) Conclusions: MAE is a useful and green strategy to extract fatty acids from freshwater phytoplankton. Cyanobacteria can also be a beneficial source of fatty acids for biodiesel synthesis.

Off-flavors in fish and water are considered a worldwide problem. Several factors, such as the presence of phosphorus, micronutrients, and organic matter, contribute to phytoplankton proliferation and the production of off-flavors. Geosmin and 2-methylisoborneol are the most common off-flavors that confer the smell of earth or mold to water and fish. These metabolites are not considered toxic, but they can be easily transferred from water to living organisms and accumulate in the biota, up the trophic levels and to consumers, including fish species. Numerous processes have been studied to eliminate or reduce the presence of off-flavors in recirculating aquaculture systems. Managing off-flavors must be eco-friendly and consumer-friendly. Strategies against off-flavors must be efficient and low-cost. However, these solutions may be different for each fish production system. We review herein the main compounds produced by cyanobacteria that can accumulate in fish used in aquaculture that can affect the quality of food, as well as production costs and consumer preference.