A next-generation approach to assess the cyanobacterial diversity and biogeography in the High Arctic (Svalbard)

Polar ecosystems are extremely sensitive to global climate changes and human activities. Cyanobacteria are key photosynthetic organisms in these latitudes, due to their roles in soil aggregation, nitrogen fixation, carbon cycles, and secondary metabolite production, among others. Previous works indicate that different cyanobacterial taxa/communities have different impacts on the environment, in both biogeochemical cycles and bioactive compound productions. Furthermore, the presence of biogeographical patterns in microorganisms, as found in macroorganisms, is an ongoing debate. In this study, during the 2013 MicroFun expedition, we sampled 72 locations around Svalbard including diverse biotopes such as glacial forefields, tundra soils, hot springs, soil crusts, microbial mats, wet walls, cryoconites, plankton and periphyton, in order to (1) assess the biodiversity of cyanobacteria around Svalbard, (2) verify the existence of biogeographical trends around the archipelago, and (3) compare these data with other polar (cold) areas, especially Antarctica. We used a pyrosequencing approach targeting cyanobacteria-specific 16S rRNA gene sequences to deeply study the cyanobacterial communities.BIPOLES, PYROCYAN

Evolution of the Northern Rockweed, Fucus distichus, in a Regime of Glacial Cycling: Implications for Benthic Algal Phylogenetics

peer reviewedNorthern hemisphere rockweeds (Fucus) are thought to have evolved in the North Pacific and then spread to the North Atlantic following the opening of the Bering Strait. They have dispersed and widely speciated in the North Atlantic and its tributary seas. Fucus distichus is likely near the ancestral member of this genus, and studies have shown that there are several species/subspecies in this complex (i.e. F. evanescens and F. gardneri). We used phylogenetic and haplotype analyses to test the phylogenetic relationships and biogeogra- phy of F. distichus. Our data and subsequent analyses demonstrate that, unlike previous studies that lacked samples from an extensive geographical area of the Arctic and Subarc- tic, there is a distinct Arctic haplotype that is the source of subspecies in both the North Pacific and North Atlantic. Fucus distichus occupies a low tide zone habitat, and in Arctic/ Subarctic regions it is adapted to the severe stress of sea ice coverage and disturbance dur- ing many months per year. We hypothesize that the very large geographic area of Arctic and Subarctic rocky shores available to this species during interglacials, supported by large Arctic/Subarctic fringe areas as well as unglaciated refugia during glacial cycles, provided a robust population and gene pool (described by the Thermogeographic Model). This gene pool dilutes that of the more fragmented and area-limited Temperate/Boreal area popula- tions when they are brought together during glacial cycles. We suggest that similar subspe- cies complexes for a variety of Arctic/Subarctic shore biota should be examined further in this context, rather than arbitrarily being split up into numerous species

Control of algal growth on greenhouse surfaces using commercial algaecides

Greenhouses and nurseries provide ideal environments for facilitating the formation of nuisance algal mats. Algal growth poses safety concerns to horticulturists and stimulates the propagation of unwanted plant pests and pathogens. To date, few strategies and data are available to effectively manage algal problems. The effectiveness of five algaecides was tested on two varying surfaces of greenhouses in situ to elucidate the efficacy of chemical methods of removing algae. Moreover, Nostoc commune (Vaucher ex Bornet & Flahault) was treated on ceramic tiles in vitro, as it is a common alga in greenhouses and nurseries. We found that each algaecide had different effects, depending on the chemical applied, the surface to which the chemical was applied, and finally the types of algae that were targeted. Algaecides across the surfaces tested demonstrated that algal cell characteristics and communal makeup played an important role in algaecide efficacy, where mucilaginous algae were replaced by sheath-forming filamentous cyanobacteria. We found sodium carbonate peroxyhydrate to be the most effective chemical in terms of controlling Nostoc on tarp, gravel, and ceramic surfaces

Chromatographic analysis and antiproliferative potential of aqueous extracts of Punica granatum fruit peels using the Allium cepa test

Punica granatum L., conhecida como romanzeira, é originária da Ásia e encontra-se distribuída por todo Brasil. É usada para o tratamento de doenças inflamatórias, infecciosas e respiratórias. Em decorrência da grande utilização de recursos fitoterápicos, é necessário esclarecer à população sobre a grande quantidade de substâncias existentes nas plantas e sobre os benefícios e prejuízos de tais substâncias à saúde. O presente trabalho objetivou realizar a análise cromatográfica e o estudo da genotoxicidade dos extratos aquosos das cascas dos frutos de P. granatum através do teste de Allium cepa L. Para a montagem do experimento, foram utilizados 7 tratamentos: T1-água destilada, T2-chá 5 g.L-1, T3-chá 10 g.L-1, T4-glifosato a 9,6%, T5-glifosato para recuperação em água destilada, T6-glifosato para recuperação em chá 5 g.L-1 e T7-glifosato para recuperação em chá 10 g.L-1. As radículas foram coletadas e fixadas em etanol:ácido acético (3:1) por 24 horas, e armazenadas em álcool 70%, sob refrigeração. Realizou-se análise por cromatografia líquida de alta eficiência para quantificação dos compostos fenólicos. Nos extratos de P. granatum foram observados em maior quantidade: ácido gálico, catequina, ácido cafeico e rutina. Além disso, os extratos demonstraram potencial antiproliferativo, sem apresentar atividade antimutagênica e genotóxica.Punica granatum L., locally known as romanzeira, is native to Asia but found throughout Brazil. P. granatum is used for treating inflammatory, infectious and respiratory diseases. The aim of this study was to evaluate the chromatography and genotoxicity of an aqueous extract of P. granatum (pomegranate) fruit peel using the Allium cepa L. test. The experiment set-up entailed 7 treatments: T1-distilled water, T2-tea 5 g.L-1, T3-tea 10 g.L-1, T4-glyphosate at 9.6%, T5-glyphosate with subsequent recovery in distilled water, T6-glyphosate with subsequent recovery in tea 5 g.L-1 and T7-glyphosate with subsequent recovery in tea 10 g.L-1. The rootlets were collected and fixed in ethanol:acetic acid (3:1) for 24 hours, then stored in 70% ethanol under refrigeration. Analysis was performed using high performance liquid chromatography for the quantification of the extracted phenolic compounds. Gallic acid, catechin, caffeic acid, and rutin were abundant in the extracts of P. granatum. The extracts were found to exhibit antiproliferative potential but not antimutagenic or genotoxic activity

STUDIES OF PERIPHYTIC ALGAE ON ALGAL TURF SCRUBBERS^TM ALONG THE CHESAPEAKE BAY: COMMUNITY STRUCTURE, SYSTEMATICS, AND INFLUENCING FACTORS

This is an ecological and systematic study of periphytic algae growing in an ecologically-engineered system used for water quality improvement: the Algal Turf Scrubber or ATSTM. This technology consists of an attached algal community growing on screens in a shallow floway through which water is pumped. The study was conducted on small-scale, experimental floways at three sites within the Chesapeake Bay watershed: on the Susquehanna River in southeastern Pennsylvania (freshwater) and on the Great Wicomico and York Rivers in Virginia (brackish water). A total of 330 taxa were identified at the sites from 2008-2011. The majority of taxa at all three sites belonged to the phylum Bacillariophyta, but a large number of taxa from Chlorophyta and, to a lesser degree, Cyanobacteria were also found at the freshwater site. Algae found in the ATSTM exhibited a diversity of life forms and modes of attachment within the community. Although these system appear to be dominated by a "canopy" of attached, filamentous species, more than half of the total abundance (cell density) were solitary, unattached taxa that grow as an "understory" within the three dimensional structure of the community. Longitudinal patterns were examined on the longest floways (90 m long) at the freshwater site. The community nutrient uptake rate (mass of nitrogen or phosphorus m-2 day-1) for the harvested algal biomass was found to decline from the top to the bottom of the floway for a system constructed at 2% slope but no distinct pattern was found for a system constructed at 1% slope. The majority of algal taxa were evenly distributed along the floway from top to the bottom, in terms of frequency of occurrence, suggesting a general lack of longitudinal specialization within the community. A detailed review of the systematics of the Order Oscillatoriales (Cyanobacteria) found on the ATSTM was undertaken since this group has not been studied much in the Chesapeake Bay watershed. Twenty-four taxa were examined, described morphologically and their nomenclature reviewed. Comparing 16s rRNA gene analyses of planktonic and periphytic Pseudanabaena, it was suggested that periphytic Pseudanabaena be revised and elevated to a new genus, Ilyonema

Utilisation du pyroséquencage 454 pour l'évaluation de la diversité des cyanobactéries

A pilot run was carried out on Antarctic microbial mat samples in order to test different protocols for 454 pyrosequencing and bioinformatic analyses. An artificial community was assembled using22 cyanobacterial strains in two different abundance distributions. Bioinformatic analyses were carried out on the artificial communities using variations of the mothur and UPARSE pipelines. Moreover, different DNA extraction methods, technical replicates and biases arising from direct barcoded primer amplification were assessed using five microbial mat and soil crust samples. A great variation in richness estimates was observed using different bioinformatic pipelines, with UPARSE generating the most consistent results. On the other hand, community structures observed using different DNA extraction protocols were statistically similar. The same was observed for the technical replicates. Moreover, the use of barcoded primers did not influence the observed community structure.CCAMBI

Identification taxonomique des cyanobactéries par une approche polyphasique

In this chapter, we shall discuss the criteria and methods to be adopted for the taxonomic identification and classification of cyanobacteria. This includes a brief introduction of the two Codes of Nomenclature ruling in parallel on the valid naming of these organisms. We shall then present the major steps important for cyanobacterial taxa identification and their nomenclature. These include: 1) determination of morphology by light microscopy; 2) genetic characterization by single and/or multilocus sequence typing; 3) the assignment of the organism to a taxonomic entity (genus, species, eco- and/or genotype within a species) by reference to, and phylogenetic analysis of, cyanobacterial nucleotide sequences available in public repositories. Ideally, these methods should be accompanied by the determination of other relevant properties (ultrastructural, physiological, biochemical, and ecological characteristics) that may help to define/redefine and circumscribe the cyanobacterial taxon under study.B-BLOOMS, CCAMBIO, CYANOCOS