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Journal of Phycology

Fernando Gómez
The marine dinoflagellate Erythropsidinium possesses an ocelloid, the most elaborate photoreceptor organelle known in a unicellular organism, and a piston, a fast contractile appendage unknown in any other organism. The ocelloid is able to rotate, often before the cell swims. The ocelloid contains lenses that function to concentrate light. The flagellar propulsion is atrophied, and the piston is responsible for locomotion through successive extensions and contractions. During the 'locomotion mode', the contraction is ~4 times faster than the extension...
February 16, 2017: Journal of Phycology
Leigh W Tait, Ian Hawes, David R Schiel
Global declines of macroalgal beds in coastal waters have prompted a plethora of studies attempting to understand the drivers of change within dynamic nearshore ecosystems. Photosynthetic measurements are good tools for assessing the consequences of numerous stressors of macroalgae, but there is somewhat of a disconnection between studies that focus on organism-specific ecophysiological responses and those that address causes and consequences of shifts in macroalgal productivity. Our goal is to highlight the applications of two complementary tools for measuring photosynthesis - variable chlorophyll-a fluorescence and photorespirometry - and provide guidance for the integration of physiology and ecology to understand the drivers of change in macroalgal communities...
February 16, 2017: Journal of Phycology
Joshua R Evans, Gary W Saunders
Unexpected contaminants uncovered during routine COI-5P DNA barcoding of British Columbia Kallymeniaceae indicated the presence of a novel lineage allied to the family Meiodiscaceae, Palmariales. Available rbcL data for species of this family were used to design specific primers to screen for the presence of the meiodiscacean species in 534 kallymeniacean specimens primarily from British Columbia, Canada. Ultimately, 43 positive PCR products representing six diverse genetic groups from nine host species were uncovered; three are described here in the new genus Kallymenicola gen...
February 14, 2017: Journal of Phycology
Linda Tonk, Eugenia M Sampayo, Aaron Chai, Verena Schrameyer, Ove Hoegh-Guldberg
The broad range in physiological variation displayed by Symbiodinium spp. has proven imperative during periods of environmental change and contribute to the survival of their coral host. Characterizing how host and Symbiodinium community assemblages differ across environmentally distinct habitats provides useful information to predict how corals will respond to major environmental change. Despite the extensive characterizations of Symbiodinium diversity found amongst reef cnidarians on the Great Barrier Reef substantial biogeographic gaps exist, especially across inshore habitats...
February 14, 2017: Journal of Phycology
Anchittha Satjarak, John A Burns, Eunsoo Kim, Linda E Graham
Mitochondria are archetypal eukaryotic organelles that were acquired by endosymbiosis of an ancient species of alpha-proteobacteria by the last eukaryotic common ancestor. The genetic information contained within the mitochondrial genome has been an important source of information for resolving relationships among eukaryotic taxa. In this study, we utilized mitochondrial and chloroplast genomes to explore relationships among prasinophytes. Prasinophytes are represented by diverse early-diverging green algae whose physical structures and genomes have the potential to elucidate the traits of the last common ancestor of the Viridiplantae (or Chloroplastida)...
February 12, 2017: Journal of Phycology
Anja Rösler, Francisco Perfectti, Viviana Peña, Julio Aguirre, Juan Carlos Braga
The temporal dimension of the most recent Corallinaceae (order Corallinales) phylogeny was presented here, based on first occurrence time estimates from the fossil record. Calibration of the molecular clock of the genetic marker SSU entailed a separation of Corallinales from Hapalidiales in the Albian (Early Cretaceous ~ 105 mya). Neither the calibration nor the fossil record resolved the succession of appearance of the first three emerging subfamilies: Mastophoroideae, Corallinoideae, and Neogoniolithoideae...
February 12, 2017: Journal of Phycology
David H Jewson, David M Harwood
The earliest known diatom fossils with well-preserved siliceous frustules are from Lower Cretaceous neritic marine deposits in Antarctica. In this study, we analyzed the cell wall structure to establish whether their cell and life cycles were similar to modern forms. At least two filamentous species (Basilicostephanus ornatus and Archepyrgus melosiroides) had girdle band structures that functioned during cell division in a similar way to present day Aulacoseira species. Also, size analyses of cell diameter indicated that the cyclic process of size decline and size restoration used to time modern diatom life cycles was present in five species from the Lower Cretaceous (B...
February 7, 2017: Journal of Phycology
Pablo P Leal, Catriona L Hurd, Pamela A Fernández, Michael Y Roleda
The absorption of anthropogenic CO2 by the oceans is causing a reduction in the pH of the surface waters termed ocean acidification (OA). This could have substantial effects on marine coastal environments where fleshy (non-calcareous) macroalgae are dominant primary producers and ecosystem engineers. Few OA studies have focused on the early life stages of large macroalgae such as kelps. This study evaluated the effects of seawater pH on the ontogenic development of meiospores of the native kelp Macrocystis pyrifera and the invasive kelp Undaria pinnatifida, in south-eastern New Zealand...
February 6, 2017: Journal of Phycology
Zheng-Ke Li, Guo-Zheng Dai, Philippe Juneau, Bao-Sheng Qiu
Iron deficiency has been considered one of the main limiting factors of phytoplankton productivity in some aquatic systems including oceans and lakes. Concomitantly, solar ultraviolet-B radiation has been shown to have both deleterious and positive impacts on phytoplankton productivity. However, how iron-deficient cyanobacteria respond to UV-B radiation has been largely overlooked in aquatic systems. In this study, physiological responses of four cyanobacterial strains (Microcystis and Synechococcus), which are widely distributed in freshwater or marine systems, were investigated under different UV-B irradiances and iron conditions...
February 6, 2017: Journal of Phycology
Anchittha Satjarak, Linda E Graham
Prasinophytes form a paraphyletic assemblage of early diverging green algae, which have the potential to reveal the traits of the last common ancestor of the main two green lineages: 1) chlorophyte algae and 2) streptophyte algae. Understanding the genetic composition of prasinophyte algae is fundamental to understanding the diversification and evolutionary process that may have occurred in both green lineages. In this study, we sequenced the chloroplast genome of Pyramimonas parkeae NIES254 and compared it with that of P...
January 28, 2017: Journal of Phycology
Huan Qiu, Jun Mo Lee, Hwan Su Yoon, Debashish Bhattacharya
Red algae (Rhodophyta) putatively diverged from the eukaryote tree of life >1.2 billion years ago and are the source of plastids in the ecologically important diatoms, haptophytes, and dinoflagellates. In general, red algae contain the largest plastid gene inventory among all such organelles derived from primary, secondary, or additional rounds of endosymbiosis. In contrast, their nuclear gene inventory is reduced when compared to their putative sister lineage, the Viridiplantae, and other photosynthetic lineages...
January 17, 2017: Journal of Phycology
Hiroshi Kawai, Takeaki Hanyuda, Xu Gao, Makoto Terauchi, Masahiko Miyata, Sandra C Lindstrom, Nina G Klochkova, Kathy Ann Miller
We confirmed the monophyly of the Agaraceae based on phylogenetic analyses of six mitochondrial and six chloroplast gene sequences from Agarum, Costaria, Dictyoneurum, and Thalassiophyllum species, as well as representative species from other laminarialean families. However, the genus Agarum was paraphyletic, comprising two independent clades, A. clathratum/A. turneri and A. fimbriatum/A. oharaense. The latter clade was genetically most closely related to Dictyoneurum spp., and morphologically, the species shared a flattened stipe bearing fimbriae (potential secondary haptera) in the mid- to upper portion...
January 12, 2017: Journal of Phycology
Robin L Taylor, Craig J Bailey, D Wilson Freshwater
Identification of Cladophora species is challenging due to conservation of gross morphology, few discrete autapomorphies, and environmental influences on morphology. Twelve species of marine Cladophora were reported from North Carolina waters. Cladophora specimens were collected from inshore and offshore marine waters for DNA sequence and morphological analyses. The nuclear-encoded rRNA internal transcribed spacer regions (ITS) were sequenced for 105 specimens and used in Molecular Assisted Identification (MAI)...
January 12, 2017: Journal of Phycology
Jorge Dinamarca, Orly Levitan, G K Kumaraswamy, Desmond S Lun, Paul Falkowski
Under nutrient deplete conditions, diatoms accumulate between 15 to 25% of their dry weight as lipids, primarily as triacylglycerols (TAGs). As in most eukaryotes, these organisms produce TAGs via the acyl-CoA dependent Kennedy pathway. The last step in this pathway is catalyzed by diacylglycerol acyltransferase (DGAT) that acylates diacylglycerol (DAG) to produce TAG. To test our hypothesis that DGAT plays a major role in controlling the flux of carbon towards lipids, we overexpressed a specific type II DGAT gene, DGAT2D, in the model diatom Phaeodactylum tricornutum...
January 12, 2017: Journal of Phycology
Danilo E Bustamante, Boo Yeon Won, Kathy Ann Miller, Tae Oh Cho
Morphological, anatomical, and molecular sequence data were used to assess the establishment and phylogenetic position of the genus Wilsonosiphonia gen. nov. Phylogenies based on rbcL and concatenated rbcL and cox1 loci support recognition of Wilsonosiphonia gen. nov., sister to Herposiphonia. Diagnostic features for Wilsonosiphonia are rhizoids located at distal ends of pericentral cells and taproot-shaped multicellular tips of rhizoids. Wilsonosiphonia includes three species with diagnostic rbcL and cox1 sequences, W...
January 12, 2017: Journal of Phycology
Annalisa Caragnano, Daniela Basso, David Storz, Dorrit E Jacob, Federica Ragazzola, Francesca Benzoni, Eric Dutrieux
This study presents the first algal thallus (skeleton) archive of Asian monsoon strength and Red Sea influence in the Gulf of Aden. Mg/Ca, Li/Ca, and Ba/Ca were measured in Lithophyllum yemenense from Balhaf (Gulf of Aden) using laser ablation inductively coupled plasma mass spectrometry, and Mg/Ca ratio oscillation was used to reconstruct the chronology (34 y). Oscillations of element rates corresponding to the algal growth between 1974 and 2008 were compared with recorded climate and oceanographic variability...
January 9, 2017: Journal of Phycology
María García-Portela, Pilar Riobó, Francisco Rodríguez
The presence of the benthic dinophysoid dinoflagellate Sinophysis canaliculata has been reported in the Canary Islands (eastern central Atlantic) in live field observations and on fixed macroalgal samples from intertidal ponds (26 sampling sites from El Hierro, Tenerife, Gran Canaria, Fuerteventura and Lanzarote islands). In vivo Sinophysis cells were typically pale pink colored. Light microscopy and scanning electron microscopy micrographs showed a small characteristic narrow hypothecal cut that matched the original description of S...
December 30, 2016: Journal of Phycology
Paulette Peckol, Alysha B Putnam
Members of the genus Ulva are widespread and abundant in intertidal and shallow subtidal areas but there are conflicting data regarding susceptibility to herbivory. While some studies have documented that Ulva spp. were favored by a diversity of marine herbivores, other work has revealed herbivore deterrence. We investigated grazing and growth rates of the littorinid species, Littorina littorea and L. obtusata, when offered Fucus vesiculosus, Ascophyllum nodosum, Ulva lactuca and Chondrus crispus, highlighting distinctive vulnerabilities to toxic effects of U...
December 28, 2016: Journal of Phycology
Anurag Kirti, Arvind Kumar, Hema Rajaram
Anabaena sp. PCC7120 possesses three genes coding for single-stranded DNA-binding (SSB) protein, of which ssb1 was a single gene, and ssb2 and ssb3 are the first genes of their corresponding operons. Regulation of the truncated ssb genes, ssb1 (alr0088) and ssb2 (alr7559), was unaffected by N-status of growth. They were negatively regulated by the SOS-response regulatory protein LexA, as indicated by the (i) binding of Anabaena LexA to the LexA box of regulatory regions of ssb1 and ssb2, and (ii) decreased expression of the downstream gfp reporter gene in Escherichia coli upon co-expression of LexA...
December 21, 2016: Journal of Phycology
Rachael M Wade, Alison R Sherwood
The sacoglossan sea slug species complex Plakobranchus ocellatus is a common algivore throughout the tropical Pacific, including the Hawaiian Islands. Plakobranchus ocellatus is kleptoplastic - it sequesters and retains algal chloroplasts - a characteristic that can be exploited to molecularly characterize diminutive bryopsidalean algae that are typically difficult to locate, collect, and identify. Previous DNA barcode analyses of both P. ocellatus and its kleptoplasts have been conducted primarily in the western Pacific and have only minimally sampled the most eastern populations in the Hawaiian Islands...
December 19, 2016: Journal of Phycology
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