Zarconia navalis gen. nov., sp. nov., Romeriopsis navalis gen. nov., sp. nov. and Romeriopsis marina sp. nov., isolated from inter- and subtidal environments from northern Portugal.

The morphology, 16S rRNA gene phylogeny and 16S-23S rRNA gene ITS secondary structures of three strains of marine Cyanobacteria, isolated from inter- and subtidal environments from north Portugal were studied, resulting in the description of Zarconia navalis gen. nov., sp. nov. (Oscillatoriales incertae sedis), Romeriopsis navalis gen. nov., sp. nov. (Leptolyngbyaceae) and Romeriopsis marina sp. nov., named under the International Code of Nomenclature for algae, fungi, and plants. No diacritical morphological characters were found for the new genera and species. The 16S rRNA gene maximum-likelihood and Bayesian phylogenies supported that the genus Zarconia is a member of the Oscillatoriales, morphologically similar to the genera Microcoleus and Phormidium, but distant from them. The genus Romeriopsis is positioned within the Leptolyngbyaceae (Synechococcales) and is closely related to Alkalinema. The secondary structures of the D1-D1', Box B, V2 and V3 helices corroborate the phylogenetic results. Furthermore, our study supports previous observations of polyphyletic Oscillatoriales families and reinforces the need for their taxonomic revision.

Structure and Biosynthesis of Desmamides A-C, Lipoglycopeptides from the Endophytic Cyanobacterium Desmonostoc muscorum LEGE 12446.

Certain cyanobacteria of the secondary metabolite-rich order Nostocales can establish permanent symbioses with a large number of cycads, by accumulating in their coralloid roots and shifting their metabolism to dinitrogen fixation. Here, we report the discovery of two new lipoglycopeptides, desmamides A (1) and B (2), together with their aglycone desmamide C (3), from the nostocalean cyanobacterium Desmonostoc muscorum LEGE 12446 isolated from a cycad (Cycas revoluta) coralloid root. The chemical structures of the compounds were elucidated using a combination of 1D and 2D NMR spectroscopy and mass spectrometry. The desmamides are decapeptides featuring O-glycosylation of tyrosine (in 1 and 2) and an unusual 3,5-dihydroxy-2-methyldecanoic acid residue. The biosynthesis of the desmamides was studied by substrate incubation experiments and bioinformatics. We describe herein the dsm biosynthetic gene cluster and propose it to be associated with desmamide production. The discovery of this class of very abundant (>1.5% d.w.) bacterial lipoglycopeptides paves the way for exploration of their potential role in root endosymbiosis.

Discovery of Cyanobacterial Natural Products Containing Fatty Acid Residues*.

In recent years, extensive sequencing and annotation of bacterial genomes has revealed an unexpectedly large number of secondary metabolite biosynthetic gene clusters whose products are yet to be discovered. For example, cyanobacterial genomes contain a variety of gene clusters that likely incorporate fatty acid derived moieties, but for most cases we lack the knowledge and tools to effectively predict or detect the encoded natural products. Here, we exploit the apparent absence of a functional ß-oxidation pathway in cyanobacteria to achieve efficient stable-isotope-labeling of their fatty acid derived lipidome. We show that supplementation of cyanobacterial cultures with deuterated fatty acids can be used to easily detect natural product signatures in individual strains. The utility of this strategy is demonstrated in two cultured cyanobacteria by uncovering analogues of the multidrug-resistance reverting hapalosin, and novel, cytotoxic, lactylate-nocuolin A hybrids-the nocuolactylates.

Structure of Hierridin C, Synthesis of Hierridins B and C, and Evidence for Prevalent Alkylresorcinol Biosynthesis in Picocyanobacteria.

Small, single-celled planktonic cyanobacteria are ubiquitous in the world's oceans yet tend not to be perceived as secondary metabolite-rich organisms. Here we report the isolation and structure elucidation of hierridin C, a minor metabolite obtained from the cultured picocyanobacterium Cyanobium sp. LEGE 06113. We describe a simple, straightforward synthetic route to the scarcely produced hierridins that relies on a key regioselective halogenation step. In addition, we show that these compounds originate from a type III PKS pathway and that similar biosynthetic gene clusters are found in a variety of bacterial genomes, most notably those of the globally distributed picocyanobacteria genera Prochlorococcus, Cyanobium and Synechococcus.

Description of new genera and species of marine cyanobacteria from the Portuguese Atlantic coast.

Aiming at increasing the knowledge on marine cyanobacteria from temperate regions, we previously isolated and characterized 60 strains from the Portuguese foreshore and evaluate their potential to produce secondary metabolites. About 15% of the obtained 16S rRNA gene sequences showed less than 97% similarity to sequences in the databases revealing novel biodiversity. Herein, seven of these strains were extensively characterized and their classification was re-evaluated. The present study led to the proposal of five new taxa, three genera (Geminobacterium, Lusitaniella, and Calenema) and two species (Hyella patelloides and Jaaginema litorale). Geminobacterium atlanticum LEGE 07459 is a chroococcalean that shares morphological characteristics with other unicellular cyanobacterial genera but has a distinct phylogenetic position and particular ultrastructural features. The description of the Pleurocapsales Hyella patelloides LEGE 07179 includes novel molecular data for members of this genus. The filamentous isolates of Lusitaniella coriacea - LEGE 07167, 07157 and 06111 - constitute a very distinct lineage, and seem to be ubiquitous on the Portuguese coast. Jaaginema litorale LEGE 07176 has distinct characteristics compared to their marine counterparts, and our analysis indicates that this genus is polyphyletic. The Synechococcales Calenema singularis possess wider trichomes than Leptolyngbya, and its phylogenetic position reinforces the establishment of this new genus.

Impacts of Silver Nanoparticles on a Natural Estuarine Plankton Community.

Potential effects of metal nanoparticles on aquatic organisms and food webs are hard to predict from the results of single-species tests under controlled laboratory conditions, and more realistic exposure experiments are rarely conducted. We tested whether silver nanoparticles (Ag NPs) had an impact on zooplankton grazing on their prey, specifically phytoplankton and bacterioplankton populations. If Ag NPs directly reduced the abundance of prey, thereby causing the overall rate of grazing by their predators to decrease, a cascading effect on a planktonic estuarine food web would be seen. Our results show that the growth rates of both phytoplankton and bacterioplankton populations were significantly reduced by Ag NPs at concentrations of ≥500 µg L(-1). At the same time, grazing rates on these populations tended to decline with exposure to Ag NPs. Therefore, Ag NPs did not cause a cascade of effects through the food web but impacted a specific trophic level. Photosynthetic efficiency of the phytoplankton was significantly reduced at Ag NPs concentrations of ≥500 µg L(-1). These effects did not occur at relatively low concentrations of Ag that are often toxic to single species of bacteria and other organisms, suggesting that the impacts of Ag NP exposure may not be apparent at environmentally relevant concentrations due to compensatory processes at the community level.

Cyanobacterium producing cylindrospermopsin cause histopathological changes at environmentally relevant concentrations in subchronically exposed tilapia (Oreochromis niloticus).

The acute toxicity of cylindrospermopsin (CYN) has been established in rodents, based on diverse intraperitoneal an oral exposure studies and more recently in fish. But no data have been reported in fish after subchronic exposure to cyanobacterial cells containing this cyanotoxin, so far. In this work, tilapia (Oreochromis niloticus) were exposed by immersion to lyophilized Aphanizomenon ovalisporum cells added to the aquaria using two concentration levels of CYN (10 or 100 µg CYN L(-1)) and deoxy-cylindrospermopsin (deoxy-CYN) (0.46 or 4.6 µg deoxy-CYN L(-1)), during two different exposure times: 7 or 14 d. This is the first study showing damage in the liver, kidney, hearth, intestines, and gills of tilapia after subchronic exposure to cyanobacterial cells at environmental relevant concentrations. The major histological changes observed were degenerative processes and steatosis in the liver, membranous glomerulopathy in the kidney, myofibrolysis and edema in the heart, necrotic enteritis in the gastrointestinal tract, and hyperemic processes in gill lamellae and microhemorrhages. Moreover, these histopathological findings confirm that the extent of damage is related to the CYN concentration and length of exposure. Results from the morphometric study indicated that the average of nuclear diameter of hepatocytes and cross-sections of proximal and distal convoluted tubules are useful to evaluate the damage induced by CYN in the main targets of toxicity.

Trace metal concentration in a temperate freshwater reservoir seasonally subjected to blooms of toxin-producing cyanobacteria.

In situ interactions between cyanobacteria and metals were studied at Torrão reservoir (Tâmega River, North Portugal). The metal content of water and sediments from the reservoir was monitored monthly at Marco de Canaveses (seasonally subjected to toxic blooms of Microcystis aeruginosa) and upstream at Amarante (no blooms recorded), for 16 months. During the 16 months of the study period, M. aeruginosa bloomed twice at Marco de Canaveses, firstly forming a scum, and later with colonies scattered throughout the reservoir. Metals Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn were analysed in the sediment and in the water column. Cu-binding ligands in water were also determined. When no blooms were taking place, average metal levels for water and sediment were not statistically different at both locations. Therefore, it was considered that the absence of cyanobacteria blooms at Amarante was not due to differences in metal content. When blooms were taking place at Marco de Canaveses, a significant increase of metal levels in the sediment occurred simultaneously. Sediment quality guidelines showed that during this period, Cu and Pb concentrations (32.3 and 43.2 mg kg(-1), respectively) were potentially toxic. However, quantification of the exchangeable metal fraction indicated that these metals were probably not bioavailable. Concentration of Cu-binding ligands in water was higher during the blooms, indicating that cyanobacteria are capable of changing the metal speciation in situ in a reservoir.

Chemoecological screening reveals high bioactivity in diverse culturable Portuguese marine cyanobacteria.

Marine cyanobacteria, notably those from tropical regions, are a rich source of bioactive secondary metabolites. Tropical marine cyanobacteria often grow to high densities in the environment, allowing direct isolation of many secondary metabolites from field-collected material. However, in temperate environments culturing is usually required to produce enough biomass for investigations of their chemical constituents. In this work, we cultured a selection of novel and diverse cyanobacteria isolated from the Portuguese coast, and tested their organic extracts in a series of ecologically-relevant bioassays. The majority of the extracts showed activity in at least one of the bioassays, all of which were run in very small scale. Phylogenetically related isolates exhibited different activity profiles, highlighting the value of microdiversity for bioprospection studies. Furthermore, LC-MS analyses of selected active extracts suggested the presence of previously unidentified secondary metabolites. Overall, the screening strategy employed here, in which previously untapped cyanobacterial diversity was combined with multiple bioassays, proved to be a successful strategy and allowed the selection of several strains for further investigations based on their bioactivity profiles.

Synergistic allelochemicals from a freshwater cyanobacterium.

The ability of cyanobacteria to produce complex secondary metabolites with potent biological activities has gathered considerable attention due to their potential therapeutic and agrochemical applications. However, the precise physiological or ecological roles played by a majority of these metabolites have remained elusive. Several studies have shown that cyanobacteria are able to interfere with other organisms in their communities through the release of compounds into the surrounding medium, a phenomenon usually referred to as allelopathy. Exudates from the freshwater cyanobacterium Oscillatoria sp. had previously been shown to inhibit the green microalga Chlorella vulgaris. In this study, we observed that maximal allelopathic activity is highest in early growth stages of the cyanobacterium, and this provided sufficient material for isolation and chemical characterization of active compounds that inhibited the growth of C. vulgaris. Using a bioassay-guided approach, we isolated and structurally characterized these metabolites as cyclic peptides containing several unusually modified amino acids that are found both in the cells and in the spent media of Oscillatoria sp. cultures. Strikingly, only the mixture of the two most abundant metabolites in the cells was active toward C. vulgaris. Synergism was also observed in a lung cancer cell cytotoxicity assay. The binary mixture inhibited other phytoplanktonic organisms, supporting a natural function of this synergistic mixture of metabolites as allelochemicals.

The non-protein amino acid ß-N-methylamino-L-alanine in Portuguese cyanobacterial isolates.

The tailor made amino acid ß-N-methyl-amino-L-alanine (BMAA) is a neurotoxin produced by cyanobacteria. It has been associated with certain forms of progressive neurodegenerative disease, including sporadic Amyotrophic Lateral Sclerosis and Alzheimer's disease. Some different reports of BMAA in cyanobacterial blooms from lakes, reservoirs, and other water resources have been made by different investigators. We here report the detection of BMAA of both free and protein-bound produced by cyanobacteria, belonging to the Chroococcales, Oscillatoriales and Nostocales ordered. We use a rapid and sensitive HPLC-FD method that utilizes methanol elution and the Waters AQC Tag chemistry. On other hand, we have used three different assay procedures for BMAA extraction from cyanobacteria: Trichloroacetic acid (TCA), Methanol/Acetone and hydrochloric acid (HCl). All assays let successfully detect BMAA in all cyanobacteria samples analyzed. Nevertheless, with TCA and HCl extraction procedures the highest BMAA values, for free as well as protein-bound BMAA were detected. BMAA content could not be related to the taxonomy of the isolates or to their geographical origin, and no correlation between free and protein-bound BMAA concentrations were observed within or between taxonomic groups. These data offer confirmation of the taxonomic and geographic ubiquity of BMAA from naturally occurring populations of cyanobacteria, for the first time reported for estuaries.

Influence of biotic and abiotic factors on the allelopathic activity of the cyanobacterium Cylindrospermopsis raciborskii strain LEGE 99043.

Allelopathy is considered to be one of the factors underlying the global expansion of the toxic cyanobacterium Cylindrospermopsis raciborskii. Although the production and release of allelopathic compounds by cyanobacteria is acknowledged to be influenced by environmental parameters, the response of C. raciborskii remains generally unrecognized. Here, the growth and allelopathic potential of C. raciborskii strain LEGE 99043 towards the ubiquitous microalga Ankistrodesmus falcatus were analyzed under different biotic and abiotic conditions. Filtrates from C. raciborskii cultures growing at different cell densities displayed broad inhibitory activity. Moreover, higher temperature, higher light intensity as well phosphate limitation further enhanced this activity. The distinct and comprehensive patterns of inhibition verified during the growth phase, and under the tested parameters, suggest the action of several, still unidentified allelopathic compounds. It is expectable that the observed increase in allelopathic activity can result in distinct ecological advantages to C. raciborskii.

Microbial community changes elicited by exposure to cyanobacterial allelochemicals.

An increasing body of evidence points out that allelopathy may be an important process shaping microbial communities in aquatic ecosystems. Cyanobacteria have well-documented allelopathic properties, mainly derived from the evaluation of the activity of allelopathic extracts or pure compounds towards monocultures of selected target microorganisms. Consequently, little is known regarding the community dynamics of microorganisms associated with allelopathic interactions. In this laboratory-based study, a Microcystis spp.-dominated microbial community from a freshwater lake was exposed, for 15 days, to exudates from the cyanobacterium Oscillatoria sp. strain LEGE 05292 in laboratory conditions. This cyanobacterium is known to produce the allelochemicals portoamides, which were among the exuded compounds. The community composition was followed (by means of polymerase chain reaction followed by denaturing gradient gel electrophoresis and microscopic analyses) and compared to that of a non-exposed situation. Following exposure, clear differences in the community structure were observed, in particular for cyanobacteria and unicellular eukaryotic taxa. Interestingly, distinct Microcystis genotypes present in the community were differentially impacted by the exposure, highlighting the fine-scale dynamics elicited by the exudates. These results support a role for cyanobacterial allelochemicals in the structuring of aquatic microbial communities.

The phosphoprotein phosphatase family of Ser/Thr phosphatases as principal targets of naturally occurring toxins.

Phosphoprotein phosphatases (PPPs) constitute one of three otherwise unrelated families of enzymes that specialize in removing the phosphate group from phosphorylated serine and threonine residues. The involvement of PPP enzymes in the regulation of processes such as gene expression, DNA replication, morphogenesis, synaptic transmission, glycogen metabolism, and apoptosis has underscored their potential as targets for the treatment of a variety of conditions such as cancer, diabetes, or Alzheimer's disease. Interestingly, PPP enzymes also constitute the physiological target of multiple naturally occurring toxins, including microcystins from cyanobacteria and cantharidin from beetles. This review is devoted to the PPP family of enzymes--with a focus on the human PPPs--and the naturally occurring toxins that are known to potently impair their activity. The interaction of the toxins with the enzymes is evaluated in atomic detail to obtain insight on two complementary aspects: (1) which specific structural differences within the similarly folded catalytic core of the PPP enzymes explain their diverse sensitivities to toxin inhibition and (2) which structural features presented by the various toxins account for the differential inhibitory potency towards each PPP. These analyses take advantage of numerous site-directed mutagenesis studies, structure-activity evaluations, and recent crystallographic structures of PPPs bound to different toxins.

Unraveling cyanobacteria ecology in wastewater treatment plants (WWTP).

Cyanobacteria may be important components of wastewater treatment plants' (WWTP) biological treatment, reaching levels of 100% of the total phytoplankton density in some systems. The occurrence of cyanobacteria and their associated toxins in these systems present a risk to the aquatic environments and to public health, changing drastically the ecology of microbial communities and associated organisms. Many studies reveal that cyanotoxins, namely microcystins may not act as antibacterial compounds but they might have negative impacts on protozoans, inhibiting their growing and respiration rates and leading to changes in cellular morphology, decreasing consequently the treatment efficacy in WWTP. On the other side, flagellates and ciliates may ingest some cyanobacteria species while the formation of colonies by these prokaryotes may be seen as a defense mechanism against predation. Problems regarding the occurrence of cyanobacteria in WWTP are not limited to toxin production. Other cyanobacterial secondary metabolites may act as antibacterial compounds leading to the disruption of bacterial communities that biologically convert organic materials in WWTP being fundamental to the efficacy of the process. Studies reveal that the potential antibacterial capacity differs according to cyanobacteria specie and it seems to be more effective in Gram (+) bacteria. Thus, to understand the effects of cyanobacterial communities in the efficiency of the waste water treatment it will be necessary to unravel the complex interactions between cyanobacterial populations, bacteria, and protozoa in WWTP in situ studies.

Bioactivity of benthic and picoplanktonic estuarine cyanobacteria on growth of photoautotrophs: inhibition versus stimulation.

Understanding potential biochemical interactions and effects among cyanobacteria and other organisms is one of the main keys to a better knowledge of microbial population structuring and dynamics. In this study, the effects of cyanobacteria from benthos and plankton of estuaries on other cyanobacteria and green algae growth were evaluated. To understand how the estuarine cyanobacteria might influence the dynamics of phytoplankton, experiments were carried out with the freshwater species Microcystis aeruginosa and Chlorella sp., and the marine Synechocystis salina and Nannochloropsis sp. exposed to aqueous and organic (70% methanol) crude extracts of cyanobacteria for 96 h. The most pronounced effect observed was the growth stimulation. Growth inhibition was also observed for S. salina and M. aeruginosa target-species at the highest and lowest concentrations of cyanobacterial extracts. The methanolic crude extract of Phormidium cf. chalybeum LEGE06078 was effective against S. salina growth in a concentration-dependent manner after 96 h-exposure. All of the cyanobacterial isolates showed some bioactivity on the target-species growth, i.e., inhibitory or stimulating effects. These results indicate that the analyzed cyanobacterial isolates can potentially contribute to blooms' proliferation of other cyanobacteria and to the abnormal growth of green algae disturbing the dynamic of estuarine phytoplankton communities. Since estuaries are transitional ecosystems, the benthic and picoplanktonic estuarine cyanobacteria can change both freshwater and marine phytoplankton succession, competition and bloom formation. Furthermore, a potential biotechnological application of these isolates as a tool to control cyanobacteria and microalgae proliferation can be feasible. This work is the first on the subject of growth responses of photoautotrophs to cyanobacteria from Atlantic estuarine environments.

Effects of minocycline and its degradation products on the growth of Microcystis aeruginosa.

This work aimed to investigate the influence of Microcystis aeruginosa on the rate of minocycline (MNC) removal (abiotic degradation, physical binding or chemical transformation by cells) and the toxicity of MNC and its degradation products to the cyanobacterium. Most of the work was carried out in culture media in the presence or in the absence of M. aeruginosa. The rate of the MNC abiotic degradation in culture media strongly decreased with the increase of the MNC initial concentration. The exudates did not influence the rate of MNC degradation in the media. For concentrations ≥0.48 µM, the rate of the MNC removal from the media was faster in the presence of M. aeruginosa. Biotic MNC removal occurs by both physical binding by the cells (10%) and chemical transformations. EC(50) and EC(20) for MNC on the growth of M. aeruginosa were 0.92 and 0.13 µM, respectively. Interestingly, MNC degradation products might promote M. aeruginosa growth.

Modeling phaeopigment concentrations in water from a shallow mesotrophic lagoon.

Concentrations of phaeopigments (Pha) and chlorophyll a (Chl) were determined in surface waters from a temperate lagoon during six sampling campaigns at high and at low tide. In order to develop models for phaeopigment concentration in water, it was necessary to replace Chl with photosynthetic pigment concentration (Pt  = Pha+Chl) as one of the explanatory variables. Under first approximation, food availability and water temperature (T) could be considered as independent variables. The concentrations of Pha were then determined following seasonal change of response curves of the consumer community on T. However, multiple regression models with Pt , T and, eventually, salinity as explanatory variables were better able to depict Pha. All equations, developed with Pt , were also solved using Chl as an input variable. Although part of the performance was lost, such back-transformed models can be used at low/medium T and moderate to high concentrations of Chl. The developed equations about middle to long-term variations of Pha could be applied to study the biogeochemistry of contaminants related to Pha and to evaluate the dependence on temperature of phytoplankton utilization by consumers. PRACTITIONER POINTS: Phaeopigment concentration depicted by chlorophyll (Chl), temperature (T), and salinity. Better results obtained at low to medium T and moderate to high Chl concentration. Multiple regression (MR) better for extrapolation than model (S) with variable separation. Thermal response of consumer community in mesotrophic lagoon studied using model S.

New Insights in Saccharomyces cerevisiae Response to the Cyanotoxin Microcystin-LR, Revealed by Proteomics and Gene Expression.

Microcystins (MCs) are hepatotoxins produced by some cyanobacteria. They are cyclic peptides that inhibit the serine/threonine protein phosphatases (PPs) PP1 and PP2A, especially PP2A. The inhibition of PP2A triggers a series of molecular events, which are responsible for most MC cytotoxic and genotoxic effects on animal cells. It is also known that MCs induce oxidative stress in cells due to the production of reactive oxygen species (ROS). However, a complete characterization of the toxic effects of MCs is still not accomplished. This study aimed to clarify additional molecular mechanisms involved in MC-LR toxicity, using Saccharomyces cerevisiae as eukaryotic model organism. First, a shotgun proteomic analysis of S. cerevisiae VL3 cells response to 1 nM, 10 nM, 100 nM, and 1 µM MC-LR was undertaken and compared to the control (cells not exposed to MC-LR). This analysis revealed a high number of proteins differentially expressed related with gene translation and DNA replication stress; oxidative stress; cell cycle regulation and carbohydrate metabolism. Inference of genotoxic effects of S. cerevisiae VL3 cells exposed to different concentrations of MC-LR were evaluated by analyzing the expression of genes Apn1, Apn2, Rad27, Ntg1, and Ntg2 (from the Base Excision Repair (BER) DNA repair system) using the Real-Time RT-qPCR technique. These genes displayed alterations after exposure to MC-LR, particularly the Apn1/Apn2/Rad27, pointing out effects of MC-LR in the Base Excision Repair system (BER). Overall, this study supports the role of oxidative stress and DNA replication stress as important molecular mechanisms of MC-LR toxicity. Moreover, this study showed that even at low-concentration, MC-LR can induce significant changes in the yeast proteome and in gene expression.

Comparative Genomics Discloses the Uniqueness and the Biosynthetic Potential of the Marine Cyanobacterium Hyella patelloides.

Baeocytous cyanobacteria (Pleurocapsales/Subsection II) can thrive in a wide range of habitats on Earth but, compared to other cyanobacterial lineages, they remain poorly studied at genomic level. In this study, we sequenced the first genome from a member of the Hyella genus - H. patelloides LEGE 07179, a recently described species isolated from the Portuguese foreshore. This genome is the largest of the thirteen baeocyte-forming cyanobacterial genomes sequenced so far, and diverges from the most closely related strains. Comparative analysis revealed strain-specific genes and horizontal gene transfer events between H. patelloides and its closest relatives. Moreover, H. patelloides genome is distinctive by the number and diversity of natural product biosynthetic gene clusters (BGCs). The majority of these clusters are strain-specific BGCs with a high probability of synthesizing novel natural products. One BGC was identified as being putatively involved in the production of terminal olefin. Our results showed that, H. patelloides produces hydrocarbon with C15 chain length, and synthesizes C14, C16, and C18 fatty acids exceeding 4% of the dry cell weight. Overall, our data contributed to increase the information on baeocytous cyanobacteria, and shed light on H. patelloides evolution, phylogeny and natural product biosynthetic potential.