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Sergio Balzano, Isabella Percopo, Raffaele Siano, Priscillia Gourvil, Mélanie Chanoine, Marie Dominique, Daniel Vaulot, Diana Sarno
Seventy-five diatoms strains isolated from the Beaufort Sea (Canadian Arctic) in the summer of 2009 were characterized by light and electron microscopy (SEM and TEM) as well as 18S and 28S rRNA gene sequencing. These strains group into 20 genotypes and 17 morphotypes and are affiliated with the genera Arcocellulus, Attheya, Chaetoceros, Cylindrotheca, Eucampia, Nitzschia, Porosira, Pseudo-nitzschia, Shionodiscus, Thalassiosira, Synedropsis. Most of the species have a distribution confined to the northern/polar area...
November 3, 2016: Journal of Phycology
Xiuning Du, William Peterson, Jennifer Fisher, Matt Hunter, Jay Peterson
In spring/summer 2015, a toxic bloom by the diatom Pseudo-nitzschia (PN) occurred along the west coast of the United States which led to closures of the harvest of razor clams and Dungeness crabs. Twice monthly observations of temperature, salinity, nutrients, chlorophyll and phytoplankton species composition allowed us to track oceanographic conditions preceding and during the development of the bloom. PN cells were first detected during late winter 2015. A PN bloom was initiated following the onset of coastal upwelling in mid-April; subsequent peaks in May and June were sustained by episodic upwelling events and reached magnitudes of 105 cells/L and 106 cells/L, 40% and 90% of the total diatom abundance, respectively...
2016: PloS One
Marilou P Sison-Mangus, Sunny Jiang, Raphael M Kudela, Sanjin Mehic
Pseudo-nitzschia blooms often occur in coastal and open ocean environments, sometimes leading to the production of the neurotoxin domoic acid that can cause severe negative impacts to higher trophic levels. Increasing evidence suggests a close relationship between phytoplankton bloom and bacterial assemblages, however, the microbial composition and succession during a bloom process is unknown. Here, we investigate the bacterial assemblages before, during and after toxic and non-toxic Pseudo-nitzschia blooms to determine the patterns of bacterial succession in a natural bloom setting...
2016: Frontiers in Microbiology
S M Bengtson Nash, M C Baddock, E Takahashi, A Dawson, R Cropp
The periodic trend to cetacean mass stranding events in the Australian island state of Tasmania remains unexplained. This article introduces the hypothesis that domoic acid poisoning may be a causative agent in these events. The hypothesis arises from the previously evidenced role of aeolian dust as a vector of iron input to the Southern Ocean; the role of iron enrichment in Pseudo-nitzschia bloom proliferation and domoic acid production; and importantly, the characteristic toxicosis of domoic acid poisoning in mammalian subjects leading to spatial navigation deficits...
August 16, 2016: Bulletin of Environmental Contamination and Toxicology
Sing Tung Teng, Suh Nih Tan, Hong Chang Lim, Viet Ha Dao, Stephen S Bates, Chui Pin Leaw
Forty-eight isolates of Pseudo-nitzschia species were established from the Miri coast of Sarawak (Malaysian Borneo) and underwent TEM observation and molecular characterization. Ten species were found: P. abrensis, P. batesiana, P. fukuyoi, P. kodamae, P. lundholmiae, P. multistriata, P. pungens, P. subfraudulenta, as well as two additional new morphotypes, herein designated as P. bipertita sp. nov. and P. limii sp. nov. This is the first report of P. abrensis, P. batesiana, P. kodamae, P. fukuyoi and P. lundholmiae in coastal waters of Malaysian Borneo...
July 12, 2016: Journal of Phycology
Sondes Melliti Ben Garali, Inès Sahraoui, Pablo de la Iglesia, Mohamed Chalghaf, Jorge Diogène, Jamel Ksouri, Asma Sakka Hlaili
The effects of inorganic and organic nitrogen supply on the growth and domoic acid (DA) production of Pseudo-nitzschia cf. seriata and Pseudo-nitzschia calliantha from Bizerte Lagoon (SW Mediterranean Sea) were studied during field and laboratory experiments. Nitrogen enrichments (40 µM NO3 (-); 10 µM NH4 (+); 20 µM CH4N2O) and a control, with no added N, were carried out in separate carboys with seawater collected from Bizerte Lagoon. In the field experiments, all N-enrichments resulted in significant increases in chlorophyll a concentration, and maintained exponential growth until the end of the experiment...
August 2016: Ecotoxicology
Michael C G Carlson, Nicolette D McCary, Terence S Leach, Gabrielle Rocap
Viruses are catalysts of biogeochemical cycling, architects of microbial community structure, and terminators of phytoplankton blooms. Viral lysis of diatoms, a key group of eukaryotic phytoplankton, has the potential to impact carbon export and marine food webs. However, the impact of viruses on diatom abundance and community composition is unknown. Diatom-virus dynamics were explored by sampling every month at two coastal and estuarine locations in Washington state, USA resulting in 41 new isolates of the pennate diatom Pseudo-nitzschia and 20 environmental virus samples...
2016: Frontiers in Microbiology
Isabella Percopo, Maria Valeria Ruggiero, Sergio Balzano, Priscillia Gourvil, Nina Lundholm, Raffaele Siano, Anna Tammilehto, Daniel Vaulot, Diana Sarno
A new nontoxic Pseudo-nitzschia species belonging to the P. pseudodelicatissima complex, P. arctica, was isolated from different areas of the Arctic. The erection of P. arctica is mainly supported by molecular data, since the species shares identical ultrastructure with another species in the complex, P. fryxelliana, and represents a new case of crypticity within the genus. Despite their morphological similarity, the two species are not closely related in phylogenies based on LSU, ITS and rbcL. Interestingly, P...
April 2016: Journal of Phycology
Holly A Bowers, Roman Marin, James M Birch, Christopher A Scholin, Gregory J Doucette
Many species within the diatom genus Pseudo-nitzschia are difficult to distinguish without applying molecular analytical or microscopy-based methods. DNA, antibody and lectin probes have previously been used to provide rapid and specific detection of species and strains in complex field assemblages. Recently, however, well-documented cryptic genetic diversity within the group has confounded results of DNA probe tests in particular. Moreover, the number of species descriptions within the genus continues to increase, as do insights into toxin production by both new and previously described species...
February 2016: Journal of Phycology
Sing Tung Teng, Po Teen Lim, Hong Chang Lim, María Rivera-Vilarelle, Sonia Quijano-Scheggia, Yoshinobu Takata, Michael A Quilliam, Matthias Wolf, Stephen S Bates, Chui Pin Leaw
A new species of Pseudo-nitzschia (Bacillariophyceae) is described from plankton samples collected from Port Dickson (Malacca Strait, Malaysia) and Manzanillo Bay (Colima, Mexico). The species possesses a distinctive falcate cell valve, from which they form sickle-like colonies in both environmental samples and cultured strains. Detailed observation of frustules under TEM revealed ultrastructure that closely resembles P. decipiens, yet the new species differs by the valve shape and greater ranges of striae and poroid densities...
August 2015: Journal of Phycology
Marta Estrada, Maximino Delgado, Dolors Blasco, Mikel Latasa, Ana María Cabello, Verónica Benítez-Barrios, Eugenio Fraile-Nuez, Patricija Mozetič, Montserrat Vidal
We examine the large-scale distribution patterns of the nano- and microphytoplankton collected from 145 oceanic stations, at 3 m depth, the 20% light level and the depth of the subsurface chlorophyll maximum, during the Malaspina-2010 Expedition (December 2010-July 2011), which covered 15 biogeographical provinces across the Atlantic, Indian and Pacific oceans, between 35°N and 40°S. In general, the water column was stratified, the surface layers were nutrient-poor and the nano- and microplankton (hereafter phytoplankton, for simplicity, although it included also heterotrophic protists) community was dominated by dinoflagellates, other flagellates and coccolithophores, while the contribution of diatoms was only important in zones with shallow nutriclines such as the equatorial upwelling regions...
2016: PloS One
Fuat Dursun, Türkan Yurdun, Selma Ünlü
This study reports the first evidence of domoic acid (DA), an algal neurotoxin produced by the genus Pseudo-nitzschia, from plankton net samples collected in the Sea of Marmara in December, 2010 and February, 2011. DA concentrations of plankton net samples were analyzed by high-performance liquid chromatography (HPLC), using the fluorenylmethoxycarbonyl fluorescence derivatization technique (detection limit 0.2 ng DA). The biotoxin concentrations in samples from coastal waters varied between 0.96 and 5.25 µg DA/mL...
January 2016: Bulletin of Environmental Contamination and Toxicology
S N P Suriyanti, Gires Usup
Screening of the occurrence of potentially toxic diatoms was carried out at two sites of cage cultures in Tebrau Straits, Johor. Phytoplankton samples from Sungai Pendas and Teluk Sengat were collected using a 20 μm mesh plankton net and salinity was recorded in-situ. Nitzschia and Pseudo-nitzschia cells were isolated and established into clonal cultures. All cultures were tested for domoic acid using HPLC-UV analysis and verified by LC-MS analysis. Three Nitzschia spp. and one Pseudo-nitzschia sp. were identified from these locations...
December 15, 2015: Toxicon: Official Journal of the International Society on Toxinology
Eleonora Scalco, Alberto Amato, Maria Immacolata Ferrante, Marina Montresor
Pseudo-nitzschia is a thoroughly studied pennate diatom genus for ecological and biological reasons. Many species in this genus, including Pseudo-nitzschia multistriata, can produce domoic acid, a toxin responsible for amnesic shellfish poisoning. Physiological, phylogenetic and biological features of P. multistriata were studied extensively in the past. Life cycle stages, including the sexual phase, fundamental in diatoms to restore the maximum cell size and avoid miniaturization to death, have been well described for this species...
November 2016: Protoplasma
Satoshi Nagai, Kohsuke Hida, Shingo Urushizaki, Goh Onitsuka, Motoshige Yasuike, Yoji Nakamura, Atushi Fujiwara, Seisuke Tajimi, Katsunori Kimoto, Takanori Kobayashi, Takashi Gojobori, Mitsuru Ototake
In this study, we investigated the influence of diurnal sampling bias on the community structure of plankton by comparing the biodiversity among seawater samples (n=9) obtained every 3h for 24h by using massively parallel sequencing (MPS)-based plankton monitoring at a fixed point conducted at Himedo seaport in Yatsushiro Sea, Japan. The number of raw operational taxonomy units (OTUs) and OTUs after re-sampling was 507-658 (558 ± 104, mean ± standard deviation) and 448-544 (467 ± 81), respectively, indicating high plankton biodiversity at the sampling location...
February 1, 2016: Gene
Rohinee N Paranjpye, William B Nilsson, Martin Liermann, Elizabeth D Hilborn, Barbara J George, Quanlin Li, Brian D Bill, Vera L Trainer, Mark S Strom, Paul A Sandifer
Populations of Vibrio parahaemolyticus in the environment can be influenced by numerous factors. We assessed the correlation of total (tl+) and potentially virulent (tdh+) V. parahaemolyticus in water with three harmful algal bloom (HAB) genera (Pseudo-nitzschia, Alexandrium and Dinophysis), the abundance of diatoms and dinoflagellates, chlorophyll-a and temperature, salinity and macronutrients at five sites in Washington State from 2008-2009. The variability in V. parahaemolyticus density was explained predominantly by strong seasonal trends where maximum densities occurred in June, 2 months prior to the highest seasonal water temperature...
December 2015: FEMS Microbiology Ecology
Mohamed Z Nassar, Nihal G Shams El-Din, Samiha M Gharib
Water samples were seasonally collected from 12 stations of the eastern coast of Suez Gulf during autumn of 2012 and winter, spring, and summer of 2013 in order to investigate phytoplankton community structure in relation to some physicochemical parameters. The study area harbored a diversified phytoplankton community (138 species), belonging to 67 genera. Four algal groups were represented and classified as Bacillariophyceae (90 species), Dinophyceae (28 species), Cyanophyceae (16 species), and Chlorophyceae (4 species)...
October 2015: Environmental Monitoring and Assessment
Min Cao, Xiao-Long Yuan, Guiqi Bi
Pseudo-nitzschia multiseries are common members of phytoplankton communities, which can bring about blooms in coastal and ocean. Meanwhile, the neurotoxin was produced by this species can cause amnesic shellfish poisoning in both marine mammals and human beings. Whereas the lacking of plastid genome information on this species obstacles the study of its evolutionary position. Here, the complete plastid genome sequence of Pseudo-nitzschia multiseries is presented. The genome is a circular DNA composed 111 539 bp of with one rRNA operon...
July 2016: Mitochondrial DNA. Part A. DNA Mapping, Sequencing, and Analysis
Xiao-Long Yuan, Min Cao, Gui-Qi Bi
Pseudo-nitzschia multiseries belongs to Baciuariophyta, which can produce the neurotoxin known as domoic acid, a toxin that can cause amnesic shellfish poisoning in human beings. The research aspects mainly focus on its toxicity and diversity. However, there is no mitochondrial genome information about P. multiseries. The complete mitochondrial genome of P. multiseries was obtained through amplifying. The mitogenome is 46 283 bp in length with 31.04% GC content. It has a typical cyclic structure. The genome contains 37 protein-coding genes, including unidentified open reading frames, 23 tRNAs and 2rRNAs...
July 2016: Mitochondrial DNA. Part A. DNA Mapping, Sequencing, and Analysis
M De Rijcke, M B Vandegehuchte, J Vanden Bussche, N Nevejan, L Vanhaecke, K A C De Schamphelaere, C R Janssen
Like marine diseases, harmful algal blooms (HABs) are globally increasing in frequency, severity and geographical scale. As a result, bivalves will have to face the combined threat of toxic algae and marine pathogens more frequently in the (near) future. These stressors combined may further affect the recruitment of ecologically and economically important bivalve species as HABs can affect the growth, viability and development of their larvae. To date, little is known on the specific effects of HABs on the innate immune system of bivalve larvae...
November 2015: Fish & Shellfish Immunology
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