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Journal of Phycology

Eva Rothäusler, Hannes Reinwald, Boris A López, Fadia Tala, Martin Thiel
The persistence of floating seaweeds, which depends on abiotic conditions but also herbivory, had previously been mostly tested in outdoor mesocosm experiments. In order to investigate if the obtained mesocosm results of high seaweed persistence under natural environmental conditions and under grazing pressure can be extrapolated to field situations, we conducted in situ experiments. During two summers (2007 and 2008), Macrocystis pyrifera was tethered (for 14 days) to lines in the presence and absence of the amphipod Peramphithoe femorata at three sites (Iquique, Coquimbo, Calfuco)...
March 13, 2018: Journal of Phycology
Marianna Venuleo, Mario Giordano
The diatom Phaeodactylum tricornutum was cultured in five different growth regimes to obtain cells with different composition. Pairs of populations subjected to different treatments were then mixed in a communal culture regime that differed from those of the origin. After six hours, the ratio between the two populations was verified by flow cytometry. Alterations in this ratio were found when cells previously grown at 1 mM NH4 + were mixed with GeO2 - and 0.5 mM NH4 + -grown cells. The nutritional background may thus make cells differently suited to new environmental conditions and afford advantages in terms of reproductive potential...
March 12, 2018: Journal of Phycology
Andrew McMinn, Shihong Lee
Micro glucose biosensors were used to measure net extracellular glucose produced by natural microphytobenthos and three diatom cultures (Amphora coffeaefirmis, Navicula menisculus, Nitzschia longissimi) from southern Tasmania, Australia. They were exposed to a light gradient in either nutrient-replete or nutrient-limiting conditions. Glucose exudation in the natural communities increased with increased light but the response in the cultures was variable. Similarly, nutrient-replete conditions elicited lower rates of glucose exudation in the natural communities but produced variable species-specific responses in the cultures...
March 7, 2018: Journal of Phycology
Kyra G Janot, Patrick T Martone
The evolution of uncalcified genicula in upright, calcified corallines has occurred at least three times independently, resulting in articulated corallines within Corallinoideae, Lithophylloideae, and Metagoniolithoideae. Genicula confer flexibility to otherwise rigid thalli, and the localization of bending at discrete intervals amplifies bending stress in genicular tissue. Genicular morphology must therefore be balanced between maintaining flexibility while mitigating or resisting stress. Genicula in the three articulated lineages differ in both cellular construction and development, which may result in different constraints on morphology...
March 5, 2018: Journal of Phycology
Bruno Briani, Marina N Sissini, Leidson A Lucena, Manuela B Batista, Iara O Costa, José M C Nunes, Caroline Schmitz, Fernanda Ramlov, Marcelo Maraschin, Nathalie Korbee, Leonardo Rörig, Paulo A Horta, Félix L Figueroa, José B Barufi
Mycosporine-like amino acids (MAA) are ultraviolet screen substances synthesized by marine algae. The physiological function of these substances is related to cellular protection against UV radiation and as a protective mechanism against oxidative stress. These substances can be found mainly in the ocean, among red seaweeds. Its concentration in organisms has been related to ultraviolet radiation and availability of inorganic nitrogen in the environment. We start our study of MAA content in different species to understand if environmental conditions influence the concentration of MAAs in red seaweeds...
March 5, 2018: Journal of Phycology
Adi Volpert, Shiri Graff van Creveld, Shilo Rosenwasser, Assaf Vardi
Diatoms are one of the key phytoplankton groups in the ocean, forming vast oceanic blooms and playing a significant part in global primary production. To shed light on the role of redox metabolism in diatom's acclimation to light-dark transition and its interplay with cell fate regulation, we generated transgenic lines of the diatom Thalassiosira pseudonana that express the redox-sensitive green fluorescent protein (roGFP) targeted to various subcellular organelles. We detected organelle specific redox patterns in response to oxidative stress, indicating compartmentalized antioxidant capacities...
March 5, 2018: Journal of Phycology
Laura Bretherton, Alicia Williams, Jennifer Genzer, Jessica Hillhouse, Manoj Kamalanathan, Zoe Finkel, Antonietta Quigg
Culture experiments were conducted on ten phytoplankton species to examine their biological and physiological responses during exposure to oil and a combination of oil and dispersant. The species tested included a range of taxa typically found in the Gulf of Mexico such as cyanobacteria, chlorophytes and diatoms. Cultures were exposed to Macondo surrogate oil using the water accommodated fraction (WAF), and dispersed oil using a chemically enhanced WAF (CEWAF) and diluted CEWAF (DCEWAF), to replicate conditions following the Deepwater Horizon spill in the Gulf of Mexico...
February 21, 2018: Journal of Phycology
Jonathan P Harris, Barry A Logan
Mastocarpus stellatus and Chondrus crispus often co-occur in the lower intertidal of Northern Atlantic rocky shorelines. At our field site along the Maine coast (USA), Mastocarpus stellatus thalli possessed greater contents of proline when compared with thalli of Chondrus crispus. In addition, M. stellatus thalli acclimated to colder growth conditions in winter/early spring by increasing proline content several fold; no seasonal acclimation in proline content was observed in C. crispus. Proline accumulates in the tissues of a broad diversity of freezing-tolerant organisms and is among the most common cryoprotectant molecules...
February 17, 2018: Journal of Phycology
Li Wei, Jian Xu
Epigenetic factors such as histone modifications play integral roles in plant development and stress response, yet their implications in algae remain poorly understood. In the industrial oleaginous microalgae Nannochloropsis spp., the lack of an efficient methodology for chromatin immunoprecipitation (ChIP), which determines the specific genomic location of various histone modifications, has hindered probing the epigenetic basis of their photosynthetic carbon conversion and storage as oil. Here, a detailed ChIP protocol was developed for Nannochloropsis oceanica, which represents a reliable approach for the analysis of histone modifications, chromatin state, and transcription factor binding sites at the epigenetic level...
February 14, 2018: Journal of Phycology
Maja Mejdandžić, Sunčica Bosak, Teofil Nakov, Elizabeth Ruck, Sandi Orlić, Marija Gligora Udovič, Petra Peharec Štefanić, Igor Špoljarić, Gordan Mršić, Zrinka Ljubešić
The diatom genus Entomoneis is known from the benthos and plankton of marine, brackish, and fresh waters. Entomoneis includes diatoms with a bilobate keel elevated above the valve surface, a sigmoid canal raphe, and numerous girdle bands. Owing mostly to the scarcity of molecular data for a diverse set of species, the phylogeny of Entomoneis has not been investigated in depth. The few previous studies that included Entomoneis were focused on broader questions and the available data were from a small number of either unidentified Entomoneis or well-known species (e...
February 8, 2018: Journal of Phycology
Hong Chang Lim, Suh Nih Tan, Sing Tung Teng, Nina Lundholm, Emma Orive, Helena David, Sonia Quijano-Scheggia, Sandric Chee Yew Leong, Matthias Wolf, Stephen S Bates, Po Teen Lim, Chui Pin Leaw
Analyses of the mitochondrial cox1, the nuclear-encoded large subunit (LSU) and the internal transcribed spacer 2 (ITS2) RNA coding region of Pseudo-nitzschia revealed that the P. pseudodelicatissima complex can be phylogenetically grouped into three distinct clades (Groups I-III), while the P. delicatissima complex forms another distinct clade (Group IV) in both the LSU and ITS2 phylogenetic trees. It was elucidated that comprehensive taxon sampling (sampling of sequences), selection of appropriate target genes and outgroup, and alignment strategies influence the phylogenetic accuracy...
January 27, 2018: Journal of Phycology
Chelsea D Villanueva, Petr Hašler, Petr Dvořák, Aloisie Poulíčková, Dale A Casamatta
Cyanolichens are an assemblage of fungi and cyanobacteria from diverse, cosmopolitan habitats. Typically composed of a single species of cyanobacterium, with or without another eukaryotic alga, here we present two novel cyanobionts isolated from an undescribed tripartite lichen. This endolithic lichen was isolated from a granite cemetery tombstone from Jacksonville, FL, and contains two potentially nitrogen-fixing cyanobionts. Employing a total evidence approach, we characterized the cyanobionts using molecular (the 16S rDNA and ITS gene region), morphological, and ecological data...
January 27, 2018: Journal of Phycology
Vivien Hotter, Karin Glaser, Anja Hartmann, Markus Ganzera, Ulf Karsten
In many regions of the world, aeroterrestrial green algae of the Trebouxiophyceae (Chlorophyta) represent very abundant soil microorganisms, and hence their taxonomy is crucial to investigate their physiological performance and ecological importance. Due to a lack in morphological features, taxonomic and phylogenetic studies of Trebouxiophycean algae can be a challenging task. Since chemotaxonomic markers could be a great assistance in this regard, 22 strains of aeroterrestrial Trebouxiophyceae were chemically screened for their polyol-patterns as well as for mycosporine-like amino acids (MAAs) in their aqueous extracts using RP-HPLC and LC-MS...
January 18, 2018: Journal of Phycology
Emily T Johnston, Kyatt R Dixon, John A West, Nurliah Buhari, Morgan L Vis
The freshwater red algal order Thoreales has triphasic life history composed of a diminutive diploid 'Chantransia' stage, a distinctive macroscopic gametophyte with multi-axial growth and carposporophytes that develop on the gametophyte thallus. This order is comprised of two genera, Thorea and Nemalionopsis. Thorea has been widely reported with numerous species, whereas Nemalionopsis has been more rarely observed with only a few species described. DNA sequences from three loci (rbcL, cox1 and LSU) were used to examine the phylogenetic affinity of specimens collected from geographically distant locations including North America, South America, Europe, Pacific Islands, Southeast Asia, China and India...
January 17, 2018: Journal of Phycology
Ga Hun Boo, Line Le Gall, Il Ki Hwang, Kathy Ann Miller, Sung Min Boo
The genus Ptilophora currently includes 16 species occurring mostly in subtidal habitats of the Indo-Pacific Ocean, but its global diversity and biogeography are poorly understood. We analyzed mitochondrial cox1, plastid rbcL and plastid psbA sequences from specimens collected in southern Madagascar during the 2010 Atimo Vatae expedition and studied their morphologies. Both morphological and molecular datasets demonstrated the presence of five species in southern Madagascar: Ptilophora hildebrandtii, P. pterocladioides, and three new species described here, P...
January 5, 2018: Journal of Phycology
Rebecca Guenther, Kevin Miklasz, Emily Carrington, Patrick T Martone
Early life stages of marine organisms are predicted to be vulnerable to ocean acidification. For macroalgae, reproduction and population persistence rely on spores to settle, adhere and continue the algal life cycle, yet the effect of ocean acidification on this critical life stage has been largely overlooked. We explicitly tested the biomechanical impact of reduced pH on early spore adhesion. We developed a shear flume to examine the effect of reduced pH on spore attachment time and strength in two intertidal rhodophyte macroalgae, one calcified (Corallina vancouveriensis) and one non-calcified (Polyostea robusta)...
December 29, 2017: Journal of Phycology
Masahiko Idei, Shinya Sato, Tamotsu Nagumo, David G Mann
Diploneis species have perhaps the most complex valve structure among pennate diatoms. The development of this structure was studied in D. smithii and begins with the formation of a primary band, which then develops secondary arms at both poles and the center, as in the classic Chiappino-Volcani model of raphid diatom ontogeny. Spine-like projections grow out from the primary band and secondary arms to establish the transapical ribs (virgae) of the mature valve and themselves develop spines, which are spaced first oppositely and then alternately and fuse with each other to delimit the stria pores...
December 28, 2017: Journal of Phycology
Nicole Sausen, Veronica Malavasi, Michael Melkonian
In the present study, three new strains of the rare volvocalean green alga Lobomonas were isolated from field-collected samples, one from Sardinia (Italy) and two from Argentina and comparatively studied. The Sardinian and one of the Argentinian strains were identified as Lobomonas francei, the type species of the genus, while the second Argentinian strain corresponded to L. panduriformis. Two additional nominal species of Lobomonas from culture collections (L. rostrata and L. sphaerica) were included in the analysis and shown to be morphologically and molecularly identical to the L...
December 26, 2017: Journal of Phycology
Pablo Salgado, Santiago Fraga, Francisco Rodríguez, Isabel Bravo
A planktonic-benthic relationship has been described for many dinoflagellate species as part of their ecological strategy to overcome highly variable aquatic environments. Here, the phylogenetically and morphologically related marine dinoflagellates Protoceratium reticulatum and Ceratocorys mariaovidiorum were studied in relation to an unknown benthic life form. In vivo and fixed samples from cultures were analyzed in detail by light and scanning electron microscopy. In both species, a cell type with a morphology different from that of vegetative cells was observed in cultures grown until stationary phase...
February 2018: Journal of Phycology
Pablo Salgado, Santiago Fraga, Francisco Rodríguez, Pilar Riobó, Isabel Bravo
The family Ceratocoryaceae includes the genera Ceratocorys, Protoceratium, and Schuettiella, whose phylogenetic relationships are poorly known. Here, the new non-yessotoxin-producing species of the genus Ceratocorys, Ceratocorys mariaovidiorum sp. nov., previously reported as the toxic Protoceratium reticulatum, is described from examinations by light and scanning electron microscopy, molecular phylogeny, and toxin analyses. The species description is made from culture samples of strains CCMP1740 and CCMP404 from USA waters...
February 2018: Journal of Phycology
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