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© 2020 by the authors., Cyanobacteria and microalgae are oxygen-producing photosynthetic unicellular organisms encompassing a great diversity of species, which are able to grow under all types of extreme environments and exposed to a wide variety of predators and microbial pathogens. The antibacterial compounds described for these organisms include alkaloids, fatty acids, indoles, macrolides, peptides, phenols, pigments and terpenes, among others. This review presents an overview of antibacterial peptides isolated from cyanobacteria and microalgae, as well as their synergism and mechanisms of action described so far. Antibacterial cyanopeptides belong to different orders, but mainly from Oscillatoriales and Nostocales. Cyanopeptides have different structures but are mainly cyclic peptides. This vast peptide repertoire includes ribosomal and abundant non-ribosomal peptides, evaluated by standard conventional methodologies against pathogenic Gram-negative and Gram-positive bacteria. The antibacterial activity described for microalgal peptides is considerably scarcer, and limited to protein hydrolysates from two Chlorella species, and few peptides from Tetraselmis suecica. Despite the promising applications of antibacterial peptides and the importance of searching for new natural sources of antibiotics, limitations still persist for their pharmaceutical applications., This research was funded by FONDECYT 1170379. LR was supported by a grant (RICET RD16/0027/0010) from the Subdirección General de Redes y Centros de Investigación Cooperativa-FEDER.

Monitoring toxigenic cyanobacteria in freshwaters is of great importance due to the adverse health impacts on humans and aquatic organisms. Here we studied cyanobacterial occurrence and biodiversity in a drinking water reservoir in Tehran province, Iran. In total, nine different species representing three orders of Synechococcales, Oscillatoriales and Nostocales were isolated and classified into six families and seven genera ranging from 92.3% to 99.0% similarities in their partial 16S rDNA with GenBank sequences. The cultures were analyzed for cyanotoxins production by the Artemia salina bioassay, ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) and also screened for the presence of marker genes involved in toxins production. Ethyl acetate extracts of three strains showed more than 50% mortality on A. salina larvae after 24 h at a concentration of 500 µg/ml. Production of at least one of the cyanotoxins, microcystin (MC), cylindrospermopsin (CYN) and anatoxin-a (ATX-a), was detected in 6 of the strains. Seven MC variants with a total concentration of 130.6 ng/mg of biomass dry weight were detected for the strain Phormidium sp. UTMC6001 and molecular screening of the mcyE gene also confirmed the presence of this biomarker in its genome. Our study also revealed the production of CYN in a novel picocyanobacterial strain Cyanobium sp. UTMC6007 at 1.0 ng/mg of biomass dry weight. Considering the limited information on freshwater toxic cyanobacteria taxonomy in the Middle East, these findings will expand our knowledge and consequently aid in development of new water management policies in future.

This study focused on bioglea in thermal material sampled at Saturnia spa (Tuscany, Italy). Bioglea is the term used to define the thermal plankton consisting of biogenic substances that have been investigated little from the chemical and biological points of view. Bioglea is mainly formed of cyanobacteria, particularly from the Oscillatoriales subsection, and it seems to have an important role in the maturation of thermal mud for the development of organic matter. This cyanobacteria-dominated community develops in a large outdoor pool at the spa, where the spring water is collected, over the sediments, with matter floating at the surface. Throughout the year, the cyanobacterial species of bioglea were the same, but their relative abundance changed significantly. For chemical characterization an extractive method and several analytical techniques (HPLC, GC-MS, SPME) were used. We also studied the radical scavenging activity using in vitro tests (DPPH, ORAC, ABTS). We found various groups of compounds: saturated and unsaturated fatty acids, hydroxyl acids, alcohols, phenols, amino acids. Many of the compounds have already been identified in the mud, particularly the lipid component. SPME indicated several hydrocarbons (C11&ndash, C17) and long-chain alcohols (C12&ndash, C16). The qualitative composition of volatile substances identified in bioglea was very similar to that of the mud previously analysed. These results contribute to our knowledge on thermal photosynthetic community and its possible exploitation.

The ecological significance of marine planktonic cyanobacteria in mangrove ecosystems is not well understood from the context of community structure and functions. In this study, members of the marine planktonic cyanobacterial communities were elucidated based on 16S rRNA sequencing (clone libraries and Illumina sequencing) and microscopic approaches from the Sundarbans Biological Observatory Time Series (SBOTS) stations Stn1 and Stn 3 located in and around Mooriganga estuary, Indian Sundarbans over 6 months representing monsoon and post-monsoon seasons of 2012. In total 222 sequences were marine planktonic cyanobacteria-like and were dominated by three major clades of Synechococcus-like 16S rRNA sequences (160 sequences). There was clear dominance of Synechococcus sp. KORDI-78 like sequences (71 sequences) in both monsoon and post-monsoon seasons from the study area. Although in very low numbers, other cyanobacterial sequences showing taxonomic affiliation with members of Chroococcales, Pleurocapsales, Oscillatoriales, and Stigonematales were also encountered. The presence of some of the representative genera belonging to the above Orders were reconfirmed by bright field microscopy from both stations of SBOTS. Presence of four novel clades of planktonic cyanobacteria were also confirmed from the study area based on molecular phylogeny thereby indicating unexplored cyanobacterial diversity is high in Sundarbans. Illumina sequencing undertaken for both stations of SBOTS in one of the monsoon months of 2014 (July) revealed low abundance of cyanobacteria-like sequences (2349 out of 4,276,863 pair-end reads) and dominance of KORDI-78 like sequences. Principal component analysis (PCA) showed that dissolved nutrients, transparency and salinity influenced the observed marine planktonic cyanobacterial assemblages of Sundarbans. There was overall dominance of Synechococcus-like 16S rRNA sequences confirming the importance of small-sized picocyanobacterial cells and their role in export of carbon in mangrove ecosystems.

Cyanobacteria are ubiquitous organisms with a relevant contribution to primary production in all range of habitats. Cyanobacteria are well known for their part in worldwide occurrence of aquatic blooms while producing a myriad of natural compounds, some with toxic potential, but others of high economical impact, as geosmin. We performed an environmental survey of cyanobacterial soil colonies to identify interesting metabolic pathways and adaptation strategies used by these microorganisms and isolated, sequenced and assembled the genome of a cyanobacterium that displayed a distinctive earthy/musty smell, typical of geosmin, confirmed by GC-MS analysis of the culture’s volatile extract. Morphological studies pointed to a new Oscillatoriales soil ecotype confirmed by phylogenetic analysis, which we named Microcoleus asticus sp. nov. Our studies of geosmin gene presence in Bacteria, revealed a scattered distribution among Cyanobacteria, Actinobacteria, Delta and Gammaproteobacteria, covering different niches. Careful analysis of the bacterial geosmin gene and gene tree suggests an ancient bacterial origin of the gene, that was probably successively lost in different time frames. The high sequence similarities in the cyanobacterial geosmin gene amidst freshwater and soil strains, reinforce the idea of an evolutionary history of geosmin, that is intimately connected to niche adaptation.

The prokaryotic filamentous marine cyanobacteria are photosynthetic microbes that are found in diverse marine habitats, ranging from epiphytic to endolithic communities. Their successful colonization in nature is largely attributed to genetic diversity as well as the production of ecologically important natural products. These cyanobacterial natural products are also a source of potential drug leads for the development of therapeutic agents used in the treatment of diseases, such as cancer, parasitic infections and inflammation. Major sources of these biomedically important natural compounds are found predominately from marine cyanobacterial orders Oscillatoriales, Nostocales, Chroococcales and Synechococcales. Moreover, technological advances in genomic and metabolomics approaches, such as mass spectrometry and NMR spectroscopy, revealed that marine cyanobacteria are a treasure trove of structurally unique natural products. The high potency of a number of natural products are due to their specific interference with validated drug targets, such as proteasomes, proteases, histone deacetylases, microtubules, actin filaments and membrane receptors/channels. In this review, the chemistry and biology of selected potent cyanobacterial compounds as well as their synthetic analogues are presented based on their molecular targets. These molecules are discussed to reflect current research trends in drug discovery from marine cyanobacterial natural products.

Halophilic and freshwater strains of cyanobacteria representing the Oscillatoriales, Nostocales, Chroococcales, and Synechococcales orders of Cyanophyta were examined to determine (i) the resistance of their cultures when suppressed by the presence of exogenous methoxylated and methylated derivatives of 2'-hydroxychalcone, (ii) morphological changes in cells treated with the tested chalcones and, most importantly, (iii) whether these photoautotrophic microorganisms transform chalcone derivatives in a structure- or strain-dependent manner. The growth of cyanobacterial cultures depended on chalcone derivatives and the strain; nevertheless, trends for correlations between these parameters are difficult to determine. The exposure of cyanobacteria to the tested chalcones revealed severe membrane damage that was consistent with the disruption of membrane integrity. All examined blue-green algae transformed methoxy derivatives of 2'-hydroxychalcone via hydrogenative bio-reduction and formed the corresponding hydroxydihydro derivatives with various efficiencies (≤1 - 70%), depending more on the structure than on the strain. We observed dependency of the routes and efficiency of biohydrogenation of tested chalcones on the location of the methoxyl substituent and, to a lesser extent, on cyanobacterial strains. 2'-hydroxy-4″-methylchalcone was also converted by cyanobacteria to various products, amongst which the most interesting were 2'-ethoxy derivatives. The final products of biocatalytic transformation were extracted from the cyanobacterial media, separated by high performance thin-layer chromatography (HPTLC) and identified by a combination of liquid chromatography-tandem mass spectrometry (LC-MS/MS technique) and one-dimensional (1D 1H and 13C) and two-dimensional (2D HSQC and COSY) nuclear magnetic resonance (NMR) spectroscopy.

The topsoil cyanobacteria in biological soil crusts (BSCs) play a vital role in stabilizing soil surface of disturbed habitats in water and nutrient-poor ecosystems. Currently, artificial inoculation of BSCs is considered as an effective approach to restore habitats and accelerate ecosystem regeneration. Understanding the character of cyanobacterial communities is the necessary prerequisite to explore the artificial inoculation of BSCs. For this reason, cyanobacterial communities in BSCs were compared between two mid-latitute temperate deserts with distinct precipitation patterns. The results showed that Oscillatoriales and Nostocales dominated crusts in the Tengger desert with majority of rainfall in summer and early autumn while Oscillatoriales dominated crusts in the Kyzyl kum desert with more rainfall in winter and early spring. Moreover, filamentous Microcoleus vaginatus overwhelmingly dominated all the crusts in both deserts with Mastigocladopsis sp. and Chroococcidiopsis spp. as the dominant heterocystous cyanobacteria. Of note, genus Wilmottia kept a relative stable and high abundance in both deserts. The top two abundantly shared cyanobacteria (> 1% of total sequences) were M. vaginatus and Mastigocladopsis sp. in both deserts, while 16 genera with significant variances were found between the two deserts (P

Three related new alkylphenols, termed anaephenes A-C (1-3), containing different side chains, were isolated from an undescribed filamentous cyanobacterium (VPG 16-59) collected in Guam. Our 16S rDNA sequencing efforts indicated that VPG 16-59 is a member of the marine genus Hormoscilla (Oscillatoriales). The structures of anaephenes A-C (1-3) were elucidated by spectroscopic methods, and compounds assayed for growth inhibitory activity against prokaryotic and eukaryotic cell lines. Anaephene B (2), possessing a terminal alkyne, displayed moderate activity against Bacillus cereus and Staphylococcus aureus with MIC values of 6.1 μg/mL. While 1 and 3 showed no pronounced activity in these assays, their structural features highlight the unusual biosynthetic capacity of this cyanobacterium and warrant further study.

Made available in DSpace on 2019-10-04T12:33:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-12-01 Fundacao de Amparo a Pesquisa do Estado Rio Grande do Sul Due to the undeniable importance of the role that cyanobacteria play in different ecosystems, and the new discoveries and periodic changes in their taxonomic classification, the main objective of this research was a taxonomic update of the cyanobacteria recorded in an artificial, subtropical freshwater water body. This work also aimed at the knowledge of the geographic distribution and frequency of the species throughout the study period. The analyzed pond (called Basin 7) is located in an environmental preservation area called Braskem Environmental Station (29 degrees 5157.3S and 51 degrees 2154.7W), which is part of the green belt that surrounds the set of companies of the Southern Petrochemical Complex of Rio Grande do Sul state (Brazil). The studied samples were taken from May 2000 to December 2015, using a plankton net (30 mu m), and floating thallus of cyanobacteria were collected directly by hand. Thirty-three species were identified and distributed in the orders Oscillatoriales (14), Synechococcales (12), Chroococcales (6) and Spirulinales (1). Phormidium Kutzing ex Gomont presented the highest species richness, with five species identified, and P. tergestinum (Kutzing) Anagnostidis & Komarek was the one with the highest frequency of occurrence (81.3%). Among the identified species, seven are especially important for being potentially toxic. Eucapsis pseudalpina Komarek & Hindak also stood out for its first recorded occurrence in Brazil, and Ancylothrix rivularis Martins & Branco, Arthrospira jenneri Stizenberger ex Gomont and Pannus cf. brasiliensis Malone et al. for their first recorded occurrence in Rio Grande do Sul state. For each species, diagnoses, basionyms and synonyms when appropriate, illustrations and comments are presented. Fundacao Zoobot Rio Grande do Sul, Museu Ciencias Nat, Rua Dr Salvador Franca 1427, BR-90690000 Porto Alegre, RS, Brazil Univ Estadual Paulista, Inst Biociencias Letras & Exatas, Dept Zool & Bot, Rua Cristovao Colombo 2265, BR-15054000 Sao Jose Do Rio Preto, SP, Brazil Univ Estadual Paulista, Inst Biociencias Letras & Exatas, Dept Zool & Bot, Rua Cristovao Colombo 2265, BR-15054000 Sao Jose Do Rio Preto, SP, Brazil Fundacao de Amparo a Pesquisa do Estado Rio Grande do Sul: 0435-2551/15-4

Microorganisms may play an important role in the binding of sediments and the formation of sedimentary structures, by means of the formation of biofilms and microbial mats. In this work, filamentous cyanobacteria from three different environments were compared: a biofilm from a lacustrine environment with intervals of flooding/desiccation, a biofilm from a continental saline environment, and a microbial mat from a thermal spring. The optical identification of the cyanobacteria allowed to establish that in the biofilms there is a dominance of the Order Oscillatoriales, while in the microbial mat both cyanobacteria of the Orders Nostocales and Oscillatoriales dominated. Two rock samples isolated from the thermal spring which genesis was possibly influenced by the activity of cyanobacteria are described and classified. One of them is a travertine/microbial framestone with stromatolitic and thrombolytic texture. The second one is classified as a mudstone/microbial boundstone. Finally, a comparison between the sedimentary structures identified in those rocks with similar structures in the formations La Luna, Paja and Tetuán, deposited during regressive phases of the Colombian Cretaceous epyric sea, and microbial mat features previously described is performed. Based on morphological resemblance, fibrillar networks identified locally in those formations are interpreted as possible biolaminations originated from the activity of cyanobacteria. RESUMEN Los microorganismos pueden jugar un papel importante en la cohesión de los sedimentos y la formación de estructuras sedimentarias, a través de la formación de biopelículas y tapetes microbianos. En el presente trabajo se compararon las cianobacterias filamentosas de tres ambientes diferentes: una biopelícula de un ambiente lacustre con intervalos de inundación/desecación, una biopelícula de un ambiente continental salino, y un tapete microbiano aislado de una fuente termal. La identificación óptica de las cianobacterias permitió establecer que en las biopelículas predomina el Orden Oscillatoriales, mientras que en el tapete microbiano predominan a la vez cianobacterias de los Ordenes Nostocales y Oscillatoriales. Se describen y clasifican dos muestras de roca tomadas de la fuente termal cuya génesis posiblemente estuvo influenciada por la actividad de cianobacterias. Una de ellas es un travertino/ "framestone microbiana con textura estromatolítica y trombolítica. La segunda se clasificó como una lodolita/ "boundstone" microbiana. Finalmente, se realiza una comparación entre las estructuras sedimentarias identificadas en dichas rocas con estructuras similares en las formaciones La Luna, Tetuán y Paja, depositadas durante fases regresivas del mar epicontinental de Colombia durante el Cretácico, y las características de tapetes microbianos descritas previamente. Con base en las similitudes morfológicas, las redes fibrilares identificadas de manera localizada en dichas formaciones se interpretan como posibles bioláminas originadas por la actividad de cianobacterias.

In “Oscillatoriales” cyanobacteria (Cyanophyceae), relatively simple and uniform morphology superimposes on high genetic diversity that impedes reliable identification. The system of Cyanobacteria set forth in Bergey’s Manual of Systematic Bacteriology-2001/Systematics of Archaea and Bacteria-2015 deals with operational taxa—form-genera (“larger” genera represented by strains) unlike true cyanophycean genera represented by species. Form-genera were established on morphological criteria shared with Cyanophyceae, although they were typified by Pasteur Culture Collection (PCC) strains. Despite being important in determinative cyanobacteriology, old diagnoses of form-genera should be reappraised because, in them: (i) vague and/or ephemeral morphological characters are considered taxonomically significant; (ii) phylogenetic character, such as 16S rRNA gene sequence (16S) is missing. We identified 32 “Oscillatoriales” strains from CALU collection (St. Petersburg University, Russia) basing on core morphology traits, 16S of PCC type strains, and 16S from GenBank database. We proposed that, in experimentally oriented and ecology oriented studies, unequivocal identification can be attained via triple match: streamlined form-genus diagnosis— 16S of PCC reference strain—GenBank most similar 16S. Additionally, we traced the phylogeny of “Oscillatoriales” form-genera via 16S clustering and HIP1 fingerprinting, and suggested that these operational taxa should be replaced with monophyletic assemblages. Nucleotide sequence data reported are available in the GenBank database under the accession numbers KX263921−KX263950.

Grazing is recognized as one of the selective factors shaping the morphology and physiology of cyanobacteria. A recent study has shown that the filamentous cyanobacterium Aphanizomenon gracile stra...

Managing agricultural land, both in terms of quantity and quality, is one of the major challenges of the world. Urbanization is a powerful human-induced land use transformation that not only affects adversely the availability of arable lands, but also the soil microbial diversity crucial for maintaining fertility and other soil functions. The study reports the change in cyanobacterial diversity and community composition along a rural-urban gradient, through amplicon sequencing using Illumina MiSeq approach. Urbanization significantly altered the diversity, abundance and community composition of cyanobacteria that vary along the gradient. Rural soils had the highest diversity and maximal abundance of uncultured cyanobacteria, followed by sub-urban and urban soils. In general, along the gradient Oscillatoriales (non-heterocystous forms) were the most abundant taxa, while abundance of Nostocales (i.e., heterocyst bearing N2-fixers) increased in the urban soil. The favored growth of specific taxa in urban soils indicates biotic homogenization. The relative dominance of genus Leptolyngbya in urban and sub-urban soils could be used as an indicator of urbanization.

Most of Fildes Peninsula is ice-free during summer thereby allowing for formation of networks of creeks with meltwater from Collins Glacier and snowmelt. A variety of benthic microbial mats develop within these creeks. The composition of these microbial communities has not been studied in detail. In this report, clone libraries of bacterial and cyanobacterial 16S rRNA genes were used to describe the microbial community structure of four mats near a shoreline of Drake Passage. Samples were collected from four microbial mats, two at an early developmental stage (December) and two collected latter in late summer (April). Sequence analysis showed that filamentous Cyanobacteria, Alphaproteobacteria, and Betaproteobacteria were the most abundant ribotypes. Diversity indices were comparable for the four mats. Bacterial libraries from mat samples collected in December represented primarily Alphaproteobacterial and Betaproteobacterial ribotypes. In contrast, filamentous Cyanobacteria as well as Alphaproteobacteria were most abundant in libraries derived from samples collected in April. Differences in relative abundances may reflect the succession of microbial communities during the austral summer. Composition of cyanobacterial orders in bacterial libraries obtained from mats collected in late summer were different compared with their corresponding cyanobacterial libraries. This may be the result of divergence in primer specificities. Nostocales, Oscillatoriales, and Synechococcales orders were the dominant ribotypes represented in cyanobacterial libraries. Some taxa of cyanobacteria identified using this strategy coincided with previous studies of others in the same region using microscopic techniques. Future work should combine microscopy, culture–dependent and culture–independent strategies to better describe microbial mats in maritime Antarctica.

Cyanobacterial diversity from nine hot water springs of North-Western Himalayas scattered over an area of approximately 20,000 km2 has been studied using polyphasic approach in relation to important ecological factors. These hot springs have hard water, with variation of temperature from 40 to 90 °C and pH from 6.8–8.0. A total of 625 cyanobacterial isolates were cultured from 150 samples. On the basis of morphology, these isolates were represented by 22 species of 11 genera. A total of 220 cyanobacterial isolates representing morpho-species from each sampling site were subjected to molecular characterization by amplified ribosomal DNA restriction analysis (ARDRA), 16S rRNA gene, rbcL gene and cpcB-IGS-cpcA phycocyanin locus region sequencing for elucidating their identity, diversity and phylogenetic relationships. ARDRA analysis revealed 22 groups of cyanobacterial isolates from selected hot water springs. Sequence analysis of 16S rRNA gene, rbcL gene and cpcB-IGS-cpcA phycocyanin locus region revealed that the identity of the majority of the cyanobacterial species was congruent with the identity based on morphological features. The identity of 3 taxa; Leptolyngbya sp. PUPCCC 112.22, Phormidium sp. PUPCCC 118.2 and Phormidium sp. PUPCCC 118.3, based on both morphological features and molecular markers, did not match with known cyanobacterial species, indicating these as new genera/species. Phylogenetic analyses revealed that taxa from selected hot springs belonging to Stigonematales are monophyletic, whereas Chroococcales and Oscillatoriales are polyphyletic. Canonical correspondence analysis of physico-chemical parameters and cyanobacterial community of each hot water spring revealed that temperature, pH, conductivity, nitrogen, sulphate and phosphate influenced cyanobacterial community structure. Further, our study has revealed that the cyanobacterial community of hot water springs is comprised of endemic as well as globally distributed representatives and is influenced by ecological parameters. The nature of the cyanobacterial community structure depended on the water chemistry rather than geographical location of the spring.

Microbial mats are common as fossils in the aquatic facies of the Lower Devonian Rhynie and Windyfield cherts. The framework-builder of these structures was most often a cyanobacterium described as Croftalania venusta; however, little is known about the other mat components. This study presents a new feature of the microbial mats that occurs in the form of variously sized bundles of entwined thin filaments; some of the bundles are sheathed, others are surrounded by a wall. A knot (or tangle) of filaments from which extend several bundles is also described. Filament size (2–4 μm wide) and morphology strongly suggest that both the bundles and the knot are manifestations of C. venusta. Simple, linear bundles correspond in basic morphology to bundles seen in the extant cyanobacterium Microcoleus (Oscillatoriales). Larger bundles that are walled and the knot likely represent parts of other organisms, such as charophyte algae or fungi, that had been secondarily invaded by C. venusta, which continued to function and proliferated inside the host. The triggers for bundle formation in C. venusta remain unknown. This discovery is nevertheless important because it supports the perception that microbial mats in the Rhynie paleoecosystem were complex communities.

Lake water level fluctuations (WLF) are an important factor driving the selection and seasonal dynamics of phytoplankton and potentially toxigenic cyanobacteria. Nevertheless, the relative importance of environmental drivers connected to WLF may be completely different, depending on the typology and use of waterbodies, latitude and climatic regimes. In this study, we investigated the impact of WLF in a large subtropical reservoir in south-eastern China (Hongfeng Reservoir, Guizhou Province). The study was based on monthly samplings carried out in 2014 in six stations. The strong increase in the water level observed in early summer caused a radical shift in the phytoplankton community. While in the pre-flooding period phytoplankton was composed of large diatoms, chrysophytes and Oscillatoriales (mostly Limnothrix sp.), the post-flooding period showed an increase in smaller and more competitive chlorophytes, smaller diatoms and cryptophytes better adapted to a fast colonisation of new and nutrient-rich environments. The environmental drivers that drove the change were dilution, flushing and interference with the seasonal water stratification processes. We concluded that, because WLF represents a complex variable integrating different physical effects in one explanatory descriptor, its value as a predictor of phytoplankton and cyanobacteria dynamics in lake ecosystems is difficult to generalise and needs to be investigated on a case-by-case basis. For this reason, considering the year-to-year hydrological variability that potentially characterise reservoirs, definite indications for management should be outlined considering more than 1-year study.

Some species of cyanobacteria synthesize toxins whose concentration during water bloom can reach values dangerous for human and animal health. Planktonic cyanobacteria are the most common and well-studied microcystins producers, hepatotoxic cyclic heptapeptides, whereas microcystin-producing benthic cyanobacteria are less known. In recent years, the mass development of benthic cyanobacteria forming extensive fouling on different substrates has been detected in the littoral zone of Lake Baikal. We found microcystins produced by benthic cyanobacteria in the biofouling on different natural and artificial substrates, including diseased and dead endemic sponges Lubomirskia baicalensis and Baikalospongia spp. collected from the littoral area of Lake Baikal. Microscopic analysis of the biofouling revealed prevalence of representatives of Nostocales and Oscillatoriales with predominance of Tolypothrix distorta that is likely the main microcystin producer in Lake Baikal. According to enzyme-linked immunosorbent assay (ELISA), microcystin concentrations in biofouling were 29.8–3050 μg/kg dry weight. We identified eight microcystin variants using MALDI-TOF/TOF; [Dha7]MC-YR was detected in most samples. The presence of microcystins in biofilms formed on the surface of the artificial substrate by Phormidium autumnale was also recorded. The data obtained demonstrated the necessity to monitor potentially toxic species and concentrations of cyanotoxins in plankton and benthos in the littoral zone of Lake Baikal, especially in the regions with intense tourist and recreational activities.

Samples were collected between August 2016 and May 2017 at Sangju-si, Gyeongsangbuk- do, Jeju-do, and Uljin-gun, Gangwon-do. As a result, one genus and six species were newly recorded in Korea. The unrecorded indigenous genus was Borzia, and the six species were Anagnostidinema acutissimum, Komvophoron bourrellyi, Hydrocoleum stankovicii, Borzia trilocularis, Phormidium tinctorium and Pseudanabaena lohchoides. Phormidium tinctorium and Pseudanabaena lohchoides had been reported to inhabit freshwater, but in this study, these were found in brackish water. It had also been reported that B. trilocularis trichomes are composed of up to 8 cells, but in this study, a maximum of 10 cells was observed.

Despite the global significance of cyanobacteria, their taxonomy is still heavily lagging behind the progress in genome sequencing. Besides nomenclatural issues and difficulties in species identification, this problem is largely a consequence of missing reference strains and sequences for many cyanobacterial taxa. In this study, a robust multilocus phylogenetic tree based on 23 conserved proteins from the current set of available genomes is presented and compared to a respective 16S rRNA gene tree. To facilitate further progress in achieving a stable system of monophyletic taxa, the phylogenetic status of eight cyanobacterial orders recently proposed in the botanical system was evaluated. While several orders addressed by previous studies (Gloeobacterales, Spirulinales, Chroococcidiopsidales, Nostocales) retain their monophyly, the remaining big groups (Synechococcales, Pleurocapsales, Chroococcales, Oscillatoriales) are polyphyletic and require thorough revision. Comparison of the 16S rRNA tree to the multilocus tree supports the careful use of this gene in distinguishing cyanobacterial genera, whereas its application at other taxonomic levels is limited.

Several new genera originally classified as the genus Phormidium, a polyphyletic and taxonomically complex genus within the Oscillatoriales, were recently described. The simple morphology of Phormidium does not reflect its genetic diversity and the delimitation of a natural group is not possible with traditional classification systems based on morphology alone. Therefore, this study used morphological, ecological, and molecular approaches to evaluate four populations morphologically similar to Ammassolinea, Kamptonema, and Ancylothrix (simple, curved, and gradually attenuated at the ends trichome), found in subtropical and tropical Brazilian regions. 16S rRNA gene sequences grouped all the strains in a highly supported clade with other two European strains isolated from thermal springs surrounding areas. The 16S-23S ITS secondary structure corroborated the phylogenetic analysis with all the strains having similar structures. Consequently, a genetically well-defined and cryptic new genus, Koinonema gen. nov., is proposed containing the aquatic, mesophilic, and morphologically homogeneous new species, Koinonema pervagatum sp. nov.

The composition of phototrophic organisms has been studied in light chestnut soils (Cambisols), alluvial meadow soils (Fluvisols), brown semidesert soils (Calcisols), sandy soils (Arenosols), and solonchaks (Solonchaks) of Astrakhan oblast. Representatives of the Cyanobacteria phylum constitute 71.3% of the total number of studied soil phototrophs. Overall, 64 species of cyanobacteria have been identified; they belong to 3 classes (Chroococceae, Chamaeciphoneae, and Hormogoneae), 4 orders (Chroococcales, Pleurocapsales, Nostocales, and Oscillatoriales), 9 families, and 19 genera. Most common species include Phormidium faveolarum, Phormidium tenue, Phormidium retzii, Phormidium ambigum, Phormidium inundatum, Phormidium bohneri, Oscillatoria woronchnii, Oscillatoria mucicola, Gloeocapsa magma, Gloeocapsa minuta, Anabaena variabilis, and Plectonema nostocorum. The assessment of similarity of the species composition of cyanobacteria and green algae in the studied soil types using the Jaccard and Sorensen similarity coefficients demonstrates that the maximum similarity coefficient reaches 0.37–0.54 for cyanobacteria and 0.67–0.80 for green algae. The high diversity of cyanobacteria and green algae denotes an important role of phototrophs in the processes of soil formation in the studied soils.

In recent years, the surfaces of endemic Baikalian sponges have exhibited signs of damage and disease such as tissue bleaching, atypical microbial films, and necrotic areas. One of the most common sources of damage on branching sponges Lubomirskia baicalensis is a reddish-brown mucous film fully or partially covering the body of the sponge. Sequencing of the 16S rDNA gene revealed that the film on the surfaces of the sponge consists of Oscillatoriales cyanobacteria belonging to the following genera: Tychonema, Phormidium, and Leptolyngbya, with 44 of the 86 identified sequences belonging to Tychonema. Cyanobacterial fouling of the Baikalian sponge may be caused by changes in environmental conditions of the sponge habitat, in particular, temperature increases and eutrophication of the lakes.

Mycosporine-like amino acids are the most common group of transparent ultraviolet radiation absorbing intracellular secondary metabolites. These molecules absorb light in the range of ultraviolet-A and -B with a maximum absorbance between 310 and 362 nm. Cyanobacteria might have faced the most deleterious ultraviolet radiation, which leads to an evolution of ultraviolet protecting mycosporine-like amino acids for efficient selection in the environment. In the last 30 years, scientists have investigated various cyanobacteria for novel mycosporine-like amino acids, applying different induction techniques. This review organizes all the cyanobacterial groups that produce various mycosporine-like amino acids. We found out that cyanobacteria belonging to orders Synechococcales, Chroococcales, Oscillatoriales, and Nostocales are frequently studied for the presence of mycosporine-like amino acids, while orders Gloeobacterales, Spirulinales, Pleurocapsales, and Chroococcidiopsidales are still need to be investigated. Nostoc and Anabaena strains are major studied genus for the mycosporine-like amino acids production. Hence, this review will give further insight to the readers about potential mycosporine-like amino acid producing cyanobacterial groups in future investigations.

Data on abundance and distribution on Cyanoprokaryota of alluvial soil of the Pryazov National Natural Park (PNNP) are presented. The PNNP is situated in the south part of Zaporizhzhya region near the Azov Sea. Sandy soils of the PNNP are suitable habitats for biodiversity conservation. Nevertheless. Cyanoprokaryota algae have been studying insufficiently and unevenly. 16 soil samples were sampled from the sandy habitats in the PNPP to study the Cyanoprokaryota. The sampling was carried out on the sample areas during 2014-2015 in various locations on Stepanivka Spit (Azov Sea), Fedotova Spit (Utlyutskyi Estuary), Tubalskyy estuary at the mouth Korsak, Taschenakskyi hearth (mouth of the river Tashchenak), Berdyansk Spit near the Krasne lake, Samples were sampled by a conventional algological method, treatment and identification of sampled material was performed in the Laboratory of Botany and Gardening of the Bogdan Chmelnitskiy Melitopol State Pedagogical University. Laboratory processing of the material was carried with culturing methods in two types of cultures: soil cultures with glasses of growth and Bold’s nutrient agar with normal and triple quantity of nitrogen (1N BBM and 3 NBBM). Identification were performed with the light binocular microscope “MICROmed XS-5520” using 40x and 100x objective lenses.Here we registered 23 cyanoprokaryota species from 3 orders (Chroococcales, Oscillatoriales, and Nostocales), 10 families (Merismopediaceae, Gomphosphaeriaceae, Microcystaceae, Chroococcaceae, Oscillatoriaceae, Phormidiaceae, Schizotrichaceae, Pseudanabaenaceae, Nostocaceae, Rivulariaceae) and 11 genera. The dominant species were Merismopedia elegans, M. glauca, Chroococcus minutus, Calothrix parietina, Leptolyngbya notata, Nostoc microscopicum, and Phormidium (Komvophoron) mucicola. Such species like Merismopedia elegans, M. glauca, Chroococcus minutus, and Calothrix parietina were found in all studied park plots with sandy soils that confirming algae wide ecological tolerance. We also discovered strong domination of aquatic species at studied habitats.

The effects of phosphate-P (PO4-P), nitrate-N (NO3-N), and calcium ion (Ca2+) on the geosmin production of Lyngbya kuetzingii UTEX 1547, a geosmin-producing cyanobacterium, were investigated. All nutrients had significant effects on geosmin production (P < 0.05). Of the three concentrations of PO4-P tested: 0, 0.20, and 5.44 mg l−1, the minimum geosmin concentration, mimimum geosmin per chlorophyll a (geosmin/Chl a), and maximum Chl a content were observed at 5.44 mg l−1. The concentration and proportion of extracellular geosmin were also the lowest at 5.44 mg l−1 PO4-P. Of the six concentrations of NO3-N (0, 2.47, 24.70, 82.50, 165.00, and 247.00 mg l−1), the geosmin concentrations were high at 82.50, 165.00, and 247.00 mg l−1, and the highest geosmin/Chl a were observed at 0 and 2.47 mg NO3-N l−1. The proportion of extracellular geosmin increased as the growth progressed at 165.00 and 247.00 mg NO3-N l−1. With respect to Ca2+, geosmin concentrations were considerably greater at 97.96 and 979.6...

Cold habitats are diminishing as a result of climate change, while at the same time little is known of the diversity or biogeography of microbes that thrive in such environments. Furthermore, despite the evident importance of cyanobacteria in polar areas, there are hardly any studies focusing on the phylogenetic relationship between the Arctic and Antarctic cyanobacteria. Here, we described cyanobacterial mats as well as epi- and endoliths collected from shallow streams and rocks, respectively, in the northwestern part of Svalbard. Thirteen populations were identified and characterized by employing morphological and molecular (16S rRNA gene sequences) techniques. Our results were compared to analogous information (available from the GenBank) and related to organisms from similar environments located in the Northern and Southern Hemispheres. In general, the morphological and molecular characterizations complemented each other, and the identified Arctic populations belonged to the following orders: Oscillatoriales (6), Nostocales (6), and Chroococcales (1). Twelve of the identified polar populations showed high similarity (94–99% 16S rRNA gene sequence) when compared to other Arctic and Antarctic cyanobacteria. Mat builder Phormidium autumnale shared only 88% similarity with sequences deposited in the GenBank. Our results demonstrate remarkable similarities of microbial life of Svalbard to that in Antarctica and the High Himalayas. Our findings are a starting point for future comparative research of the benthic as well as endolithic populations of cyanobacteria from the Arctic and Antarctica that will yield new insights into the cold and dry limits of life on Earth. They imply global distributions of the low-temperature cyanobacterial populations throughout the cold terrestrial biosphere.

Bacteria in stream biofilms contribute to stream biogeochemical processes and are potentially sensitive to the substantial levels of pollution entering urban streams. To examine the effects of contaminants on stream biofilm bacteria in situ, we exposed growing biofilms to experimental additions of nutrients [nitrogen (N), phosphorus (P), and iron (Fe)], pharmaceuticals (caffeine and diphenhydramine), nutrients plus pharmaceuticals, or no contaminants using contaminant exposure substrates (CES) in three catchments in northern Utah. We performed our study at montane and urban sites to examine the influence of existing pollution on biofilm response. We identified bacterial core communities (core) for each contaminant treatment at each land-use type (e.g., nutrient addition montane bacterial core, nutrient addition urban bacterial core, pharmaceutical addition montane bacterial core) by selecting all taxa found in at least 75% of the samples belonging to each specific grouping. Montane and urban land-use distinguished bacterial cores, while nutrients and pharmaceuticals had subtle, but nonetheless distinct effects. Nutrients enhanced the dominance of already abundant copiotrophs [i.e., Pseudomonadaceae (Gammaproteobacteria) and Comamonadaceae (Betaproteobacteria)] within bacterial cores at montane and urban sites. In contrast, pharmaceuticals fostered species-rich bacterial cores containing unique contaminant-degrading taxa within Pseudomonadaceae and Anaerolineaceae (Chloroflexi). Surprisingly, even at urban sites containing ambient pharmaceutical pollution, pharmaceutical additions increased bacterial core richness, specifically within DR-16 (Betaproteobacteria), WCHB1-32 (Bacteroidetes), and Leptotrichiaceae (Fusobacteria). Nutrients exerted greater selective force than pharmaceuticals in nutrient plus pharmaceutical addition treatments, creating bacterial cores more closely resembling those under nutrient rather than pharmaceutical addition, and promoting unique Oscillatoriales (Cyanobacteria) taxa in urban streams. Our results show that additions of N, P, and Fe intensified the dominance of already abundant copiotrophs, while additions of caffeine and diphenhydramine enabled unique taxa associated with contaminant degradation to participate in bacterial cores. Further, biofilm bacteria at urban sites remained sensitive to pharmaceuticals commonly present in waters, suggesting a dynamic interplay among pharmaceutical pollution, bacterial diversity, and contaminant degradation.

Cyanobacteria are among the most diverse morphological microorganisms that inhabit a great variety of habitats. Their presence in the Azores, a volcanic archipelago of nine islands in the middle of the North Atlantic Ocean, has already been reported. However, due to the high diversity of cyanobacteria habitats, their biodiversity is still understudied, mainly in extreme environments. To address this, a total of 156 cyanobacteria strains from Azores lakes, streams, thermal and terrestrial habitats were isolated. Identification was made based on a polyphasic approach using classical taxonomy (morphological characteristics and environmental data) and phylogeny among 81 strains assessed by maximum likelihood and Bayesian analysis of 16S rDNA partial sequences. The 156 isolates showed a high genera diversity (38) belonging to the orders Chroococcales, Nostocales, Oscillatoriales, and Synechococcales. Eleven new genera for the Azores habitats are here reported, reinforcing that cyanobacteria biodiversity in these islands is still much understudied. Phylogenetic analysis showed 14 clusters associated with these cyanobacteria orders, with evidence for six new genera and valuable information towards Microchaete/Coleospermum taxonomic revision that better reflects species environmental distribution. These results emphasize the need for cyanobacteria taxonomy revisions, through polyphasic studies, mainly in Synechococcales order and in the Microchaete/Coleospermum, Nostoc, and Anabaena genera. Rita Cordeiro was supported by a Ph.D. grant (M3.1.a/F/017/2015) from the Fundo Regional da Ciência e Tecnologia (FRCT). This work was funded by FEDER funds through the Interreg-MAC 2014-2020 Program under the projects REBECA - Red de excelencia en biotecnología azul (algas) de la región macaronesia (MAC1.1a/060) and REBECA-CCT - Red de Excelencia en Biotecnología Azul de la Región Macaronésica. Consolidación, Certificación y Transferencia (MAC2/1.1b/269), and by Portuguese National Funds, through FCT - Fundação para a Ciência e a Tecnologia, the European Union, QREN, FEDER, COMPETE, by funding the CIBIO/InBIO (project UID/BIA/ 50027/2013 and POCI-01-0145-FEDER-006821).

Restoration targets for biological soil crusts are largely unknown. We surveyed seven 80‐year‐old grazing exclosures across northern Nevada for biocrusts to quantify reference conditions at relatively undisturbed sites. Exclosures were associated with the following plant communities: Wyoming big sagebrush, black sagebrush, and areas co‐dominated by winterfat and Wyoming big sagebrush. Cover of biocrusts and shrubs were generally higher than other plant groups at these sites, regardless of being inside or outside of the exclosures, suggesting these groups make up most of the native flora across the region. Important in forming soil structure, cyanobacteria of the order Oscillatoriales were less abundant and diverse in black sagebrush communities. Grazing had a negative effect on the abundance of Oscillatoriales but not the number of algal taxa, including cyanobacteria. Abundance of light algal crusts were not influenced by plant community or grazing. Dark algal crusts were generally less abundant on grazed sites. Influences of plant community and grazing were most apparent when accounting for reproductive rates of lichens and mosses based on establishment mechanisms. Abundance of shrubs, perennial grasses, Oscillatoriales, fast reproducing biocrusts and the number of algal and cyanobacterial taxa, varied by plant community, suggesting that restoration should be plant community specific. We demonstrate the affinity of rapidly reproducing biocrusts for winterfat‐Wyoming big sagebrush co‐dominated plant communities, regardless of grazing pressure. Across sites, the effects of grazing were most evident on the abundance of Oscillatoriales and slowly reproducing biocrusts following 80 years of cessation from grazing.

Lake Magadi is an alkaline saline Lake in Kenya, which lies on the Great Eastern Rift valley. Although the lake is characterized by extremes of salt, pH and temperature, it supports diverse groups of cyanobacteria. In this study, we used different media to isolate novel groups of cyanobacteria. We recovered 11 isolates affiliated to the orders Chroococcales, Oscillatoriales, Pleurocapsales and Nostocales. Isolates affiliated to Chroococcidiopsis species had similarity values below 90% to currently characterized taxa indicating that these could be completely new phylotypes. This taxon has not been isolated before from the soda lake indicating the power of molecular techniques in identifying novel cyanobacterial taxa. Only two of the recovered isolates had 99% similarity to known organisms. Previous studies have mainly relied on microscopic examination and identification, which can lead to misidentification and subsequent assignment of an organism to the wrong taxon. The recovered isolates are a useful resource of more studies on taxonomy and secondary metabolite production.

Reports of anatoxins poisoning of wildlife and domestic animals by toxigenic cyanobacteria in streams and rivers are increasing globally. Little is known about the taxonomy, morphology and genomics of anatoxins producing species, limiting our knowledge about their environmental preferences. We isolated three benthic non-heterocystous filamentous cyanobacterial strains from the Russian River in Northern California (USA), which produce anatoxin-a and dihydroanatoxin-a. Both 16S rRNA and protein sequence phylogenetic analyses showed that the strains represent a distinct new member of the cyanobacterial genus Microcoleus (Oscillatoriales). A novel species, Microcoleus anatoxicus is described and accompanied with light microscope photomicrographs, toxin profiles and the complete anatoxin-a gene cassette with the first description of the anaK gene in Microcoleus.

Rann of Kachchh (RoK) is a unique geoformation, which is exposed to dynamic environmental changes such as salinity, temperature, and nutrients throughout the year. In this study, the pooled mat sample was examined for the cyanobacterial community structure using culture-dependent and culture-independent approaches. Taxonomic profiling was studied using amplicon sequencing that revealed the enrichment of Pseudanabaenales and Oscillatoriales by QIIME and MG-RAST, respectively. Other abundant orders were represented by Chroococcales, Nostocales, and unclassified cyanobacteria by both approaches. Nine cyanobacterial cultures were isolated from mat samples showing 90–98% similarities with available sequences in GenBank. The culture-dependent study suggested that mat was dominated by cyanobacterial orders such as Oscillatoriales—filamentous and Chroococcales—unicellular. Our results from the culture-dependent approach also indicated that despite high similarities in gene sequences, six cyanobacteria fall into the separate clade in the phylogenetic analysis that could be signs of evolution due to an extreme environment. Cultured isolates are correlated well with abundant taxa from amplicon sequencing. Further, protein profiling was done specifically for phycobiliproteins which will be helpful to elucidate their roles in light harvesting and energy transfer mechanism in the unique environment of RoK. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13205-019-1837-y) contains supplementary material, which is available to authorized users.

Blooms of planktonic cyanobacteria have long been of concern in lakes, but more recently, harmful impacts of riverine benthic cyanobacterial mats been recognized. As yet, we know little about how various benthic cyanobacteria are distributed in river networks, or how environmental conditions or other associated microbes in their consortia affect their biosynthetic capacities. We performed metagenomic sequencing for 22 Oscillatoriales-dominated (Cyanobacteria) microbial mats collected across the Eel River network in Northern California and investigated factors associated with anatoxin-a producing cyanobacteria. All microbial communities were dominated by one or two cyanobacterial species, so the key mat metabolisms involve oxygenic photosynthesis and carbon oxidation. Only a few metabolisms fueled the growth of the mat communities, with little evidence for anaerobic metabolic pathways. We genomically defined four cyanobacterial species, all which shared