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  • 1
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    Multigene phylogenetic data place monoraphid diatoms Schizostauron and Astartiella along with other fistula‐bearing genera in the Stauroneidaceae 1
    Wiley ; 2021
    In:  Journal of Phycology Vol. 57, No. 5 ( 2021-10), p. 1472-1491
    Details
    In: Journal of Phycology, Wiley, Vol. 57, No. 5 ( 2021-10), p. 1472-1491
    Abstract: Presented here are new insights into the marine monoraphid diatom genera Schizostauron and Astartiella , based on molecular and morphological data, including descriptions of new species. Although no unambiguous morphological synapomorphies between the two genera are currently recognized, they are closely related by DNA sequence data. Heterovalvate frustules of Schizostauron are characterized by a bifid stauros on the raphe‐bearing valve and intricate areolate occlusions on the sternum valve. In Astartiella , the raphe‐bearing valve is characterized by a process resembling a fistula by morphology, while the sternum valve presents a particular striation pattern. Observations by light and electron microscopy were made, along with a molecular phylogenetic analysis using a three‐gene (SSU, rbc L, and psb C) concatenated dataset. Three new Schizostauron species are described ( S. kajotkei, S . rawaii , S. papilliareae ), and two new combinations proposed ( S. citronella and S. trachyderma ) for species that were previously included either in Achnanthes and Cocconeis , respectively. Likewise, six new species of Astartiella ( A. almalikii, A. bornmanii, A. chunlianlii, A . marksii , A. persica, and A . wangii ) are described. Molecular results exclude Schizostauron and Astartiella from three clades of exclusively monoraphid diatoms, the Achnanthaceae, Cocconeidaceae, and Achnanthidiaceae, instead placing them in the Stauroneidaceae. Morphological features of Schizostauron and Astartiella , such as the stauros, fistula, and coaxial internal proximal raphe endings, are found in other genera in this clade, whereas the only common feature with monoraphid diatoms as whole group is the heterovalvy of frustules.
    Type of Medium: Online Resource
    ISSN: 0022-3646 , 1529-8817
    URL: Issue
    URL: Article
    DOI: 10.1111/jpy.v57.5
    DOI: 10.1111/jpy.13192
    RVK:
    WA 15000
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 281226-5
    detail.hit.zdb_id: 1478748-9
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  • 2
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    On Sea Turtle‐associated Craspedostauros (Bacillariophyta), with Description of Three Novel Species
    Wiley ; 2021
    In:  Journal of Phycology Vol. 57, No. 1 ( 2021-02), p. 199-218
    Details
    In: Journal of Phycology, Wiley, Vol. 57, No. 1 ( 2021-02), p. 199-218
    Abstract: The current study focuses on four species from the primarily marine diatom genus Craspedostauros that were observed growing attached to numerous sea turtles and sea turtle‐associated barnacles from Croatia and South Africa. Three of the examined taxa, C. danayanus sp. nov., C. legouvelloanus sp. nov., and C. macewanii sp. nov., are described based on morphological and, whenever possible, molecular characteristics. The new taxa exhibit characters not previously observed in other members of the genus, such as the presence of more than two rows of cribrate areolae on the girdle bands, shallow perforated septa, and a complete reduction of the stauros. The fourth species, C. alatus , itself recently described from museum sea turtle specimens, is reported for the first time from loggerhead sea turtles rescued in Europe. A 3‐gene phylogenetic analysis including DNA sequence data for three sea turtle‐associated Craspedostauros species and other marine and epizoic diatom taxa indicated that Craspedostauros is monophyletic and sister to Achnanthes . This study, being based on a large number of samples and animal specimens analyzed and using different preservation and processing methods, provides new insights into the ecology and biogeography of the genus and sheds light on the level of intimacy and permanency in the host–epibiont interaction within the epizoic Craspedostauros species.
    Type of Medium: Online Resource
    ISSN: 0022-3646 , 1529-8817
    URL: Issue
    URL: Article
    DOI: 10.1111/jpy.v57.1
    DOI: 10.1111/jpy.13086
    RVK:
    WA 15000
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 281226-5
    detail.hit.zdb_id: 1478748-9
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  • 3
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    Eukaryotic pathogens (Chytridiomycota and Oomycota) infecting marine microphytobenthic diatoms – a methodological comparison
    Wiley ; 2014
    In:  Journal of Phycology Vol. 50, No. 6 ( 2014-12), p. 1009-1019
    Details
    In: Journal of Phycology, Wiley, Vol. 50, No. 6 ( 2014-12), p. 1009-1019
    Abstract: Using sediment samples from the S olthörn tidal flat (southern N orth S ea, G ermany), collected in bi‐weekly intervals from J une to J uly 2012, a range of qualitative and quantitative screening methods for oomycete and chytrid pathogens infecting benthic diatoms were evaluated. Pre‐treatment of sediment samples using short ultrasound pulses and gradient centrifugation, in combination with C alco F luor White, showed the best results in the visualization of both pathogen groups. The highest number of infected benthic diatoms was observed in mid J uly (5.8% of the total benthic diatom community). Most infections were caused by chytrids and, in a few cases, oomycetes ( L agenisma D rebes (host: C oscinodiscus radiatus E hrenberg) and E ctrogella Zopf (hosts: D imeregramma minor in P ritchard and G yrosigma peisonis ). Among the chytrids, sporangium morphology indicated the presence of five different morphotypes, infecting mainly epipelic taxa of the orders N aviculales (e.g., N avicula digitoradiata ) and A chnanthales (e.g., A chnanthes brevipes A gardh). The presence of multiple pathogens in several epipelic diatom taxa suggests a significant role for fungal parasitism in affecting microphytobenthic diatom succession.
    Type of Medium: Online Resource
    ISSN: 0022-3646 , 1529-8817
    URL: Issue
    URL: Article
    DOI: 10.1111/jpy.2014.50.issue-6
    DOI: 10.1111/jpy.12230
    RVK:
    WA 15000
    Language: English
    Publisher: Wiley
    Publication Date: 2014
    detail.hit.zdb_id: 281226-5
    detail.hit.zdb_id: 1478748-9
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  • 4
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    Recovery and identification of Pseudo‐nitzschia (Bacillariophyceae) frustules from natural samples acquired using the environmental sample processor
    Wiley ; 2016
    In:  Journal of Phycology Vol. 52, No. 1 ( 2016-02), p. 135-140
    Details
    In: Journal of Phycology, Wiley, Vol. 52, No. 1 ( 2016-02), p. 135-140
    Abstract: 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. Therefore, a combination of classical morphological techniques and modern molecular methodologies is needed to resolve ecophysiological traits of Pseudo‐nitzschia species. Here, we present an approach to recover and identify frustules from sample collection filters used for toxin analysis onboard the Environmental Sample Processor ( ESP ), an in situ sample collection and analytical platform. This approach provides a new and powerful tool for correlating species presence with toxin detected remotely and in situ by the ESP , and has the potential to be applied broadly to other sampling configurations. This new technique will contribute to a better understanding of naturally occurring Pseudo‐nitzschia community structure with respect to observed domoic acid outbreaks.
    Type of Medium: Online Resource
    ISSN: 0022-3646 , 1529-8817
    URL: Issue
    URL: Article
    DOI: 10.1111/jpy.2016.52.issue-1
    DOI: 10.1111/jpy.12369
    RVK:
    WA 15000
    Language: English
    Publisher: Wiley
    Publication Date: 2016
    detail.hit.zdb_id: 281226-5
    detail.hit.zdb_id: 1478748-9
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  • 5
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    Energy cost and putative benefits of cellular mechanisms modulating buoyancy in aflagellate marine phytoplankton
    Wiley ; 2016
    In:  Journal of Phycology Vol. 52, No. 2 ( 2016-04), p. 239-251
    Details
    In: Journal of Phycology, Wiley, Vol. 52, No. 2 ( 2016-04), p. 239-251
    Abstract: Little information is available on the energetics of buoyancy modulation in aflagellate phytoplankton, which comprises the majority of autotrophic cells found in the ocean. Here, we computed for three aflagellate species of marine phytoplankton ( Emiliania huxleyi , Thalassiosira pseudonana , and Ethmodiscus rex ) the theoretical minimum energy cost as photons absorbed and nitrogen resource required of the key physiological mechanisms (i.e., replacement of quaternary ammonium by dimethyl‐sulfoniopropionate, storage of polysaccharides, and cell wall biosynthesis) affecting the cell's vertical movement as a function of nitrogen (N) availability. These energy costs were also normalized to the capacity of each buoyancy mechanism to modulate sinking or rising rates based on Stokes' law. The three physiological mechanisms could act as ballast in the three species tested in conditions of low N availability at a low fraction ( 〈 12%) of the total photon energy cost for growth. Cell wall formation in E. huxleyi was the least costly ballast strategy, whereas in T. pseudonana, the photon energy cost of the three ballast strategies was similar. In E. rex , carbohydrate storage and mobilization appear to be energetically cheaper than modulations in organic solute synthesis to achieve vertical migration. This supports the carbohydrate‐ballast strategy for vertical migration for this species, but argues against the theory of replacement of low‐ or high‐density organic solutes. This study brings new insights into the energy cost and potential selective advantages of several strategies modulating the buoyancy of aflagellate marine phytoplankton.
    Type of Medium: Online Resource
    ISSN: 0022-3646 , 1529-8817
    URL: Issue
    URL: Article
    DOI: 10.1111/jpy.2016.52.issue-2
    DOI: 10.1111/jpy.12390
    RVK:
    WA 15000
    Language: English
    Publisher: Wiley
    Publication Date: 2016
    detail.hit.zdb_id: 281226-5
    detail.hit.zdb_id: 1478748-9
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  • 6
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    The color of mass culture: spectral characteristics of a shallow water column through shade‐limited algal growth dynamics 1
    Wiley ; 2016
    In:  Journal of Phycology Vol. 52, No. 2 ( 2016-04), p. 252-259
    Details
    In: Journal of Phycology, Wiley, Vol. 52, No. 2 ( 2016-04), p. 252-259
    Abstract: It is envisioned that mass algal cultivation for commercial biofuels production will entail the use of large raceway pond systems, which typically have shade‐limited photosynthetic growth within depths of 20–30 cm. The attenuation of light and spectral qualities of red, green, and blue wavelengths in a 20‐cm water column as a function of Chl‐ a concentration during exponential and linear phases of growth dynamics for the marine diatom Thalassiosira pseudonana was examined under laboratory conditions. While photosynthetically available radiation ( PAR ) was in excess throughout the water column during the phase of exponential growth, PAR became rate limiting differently for red, green, and blue wavelengths during the phase of linear growth. The transition from exponential to linear growth occurred at 1–2 mg Chl‐ a  · L−1, whereby a scalar ~5 μmol photons · m−2 · s−1 at 20‐cm depth was found to occur as would be anticipated having the compensation point for where rates of photosynthesis and respiration are equal. During the phase of linear growth, red wavelengths became increasingly dominant at depth as Chl‐ a concentrations increased, being contrary to the optical conditions for those natural bodies of water that forced the evolution of phytoplankton photosynthesis. It is hypothesized this dramatic difference in water column optics between natural and synthetic environments could influence a variety of biological reactions, importantly non‐photochemical quenching capacities, which could negatively impact crop yield.
    Type of Medium: Online Resource
    ISSN: 0022-3646 , 1529-8817
    URL: Issue
    URL: Article
    DOI: 10.1111/jpy.2016.52.issue-2
    DOI: 10.1111/jpy.12393
    RVK:
    WA 15000
    Language: English
    Publisher: Wiley
    Publication Date: 2016
    detail.hit.zdb_id: 281226-5
    detail.hit.zdb_id: 1478748-9
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  • 7
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    Overexpression of a diacylglycerol acyltransferase gene in Phaeodactylum tricornutum directs carbon towards lipid biosynthesis
    Wiley ; 2017
    In:  Journal of Phycology Vol. 53, No. 2 ( 2017-04), p. 405-414
    Details
    In: Journal of Phycology, Wiley, Vol. 53, No. 2 ( 2017-04), p. 405-414
    Abstract: Under nutrient deplete conditions, diatoms accumulate between 15% to 25% of their dry weight as lipids, primarily as triacylglycerols ( TAG s). As in most eukaryotes, these organisms produce TAG s 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, DGAT 2D , in the model diatom Phaeodactylum tricornutum . The transformants had 50‐ to 100‐fold higher DGAT 2D mRNA levels and the abundance of the enzyme increased 30‐ to 50‐fold. More important, these cells had a 2‐fold higher total lipid content and incorporated carbon into lipids more efficiently than the wild type ( WT ) while growing only 15% slower at light saturation. Based on a flux analysis using 13 C as a tracer, we found that the increase in lipids was achieved via increased fluxes through pyruvate and acetyl‐CoA. Our results reveal overexpression of DAGT 2D increases the flux of photosynthetically fixed carbon towards lipids, and leads to a higher lipid content than exponentially grown WT cells.
    Type of Medium: Online Resource
    ISSN: 0022-3646 , 1529-8817
    URL: Issue
    URL: Article
    DOI: 10.1111/jpy.2017.53.issue-2
    DOI: 10.1111/jpy.12513
    RVK:
    WA 15000
    Language: English
    Publisher: Wiley
    Publication Date: 2017
    detail.hit.zdb_id: 281226-5
    detail.hit.zdb_id: 1478748-9
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  • 8
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    Heterogeneity of intron presence/absence in Olifantiella sp. (Bacillariophyta) contributes to the understanding of intron loss
    Wiley ; 2018
    In:  Journal of Phycology Vol. 54, No. 1 ( 2018-02), p. 105-113
    Details
    In: Journal of Phycology, Wiley, Vol. 54, No. 1 ( 2018-02), p. 105-113
    Abstract: Although hypotheses have been proposed and developed to interpret the origins and functions of introns, substantial controversies remain about the mechanism of intron evolution. The availability of introns in the intermediate state is quite helpful for resolving this debate. In this study, a new strain of diatom (denominated as DB 21‐1) was isolated and identified as Olifantiella sp., which possesses multiple types of 18S rDNA s (obtained from genomic DNA ; lengths ranged from 2,056 bp to 2,988 bp). Based on alignments between 18S rDNA s and 18S rRNA (obtained from cDNA ; 1,783 bp), seven intron insertion sites ( IIS s) located in the 18S rDNA were identified, each of which displayed the polymorphism of intron presence/absence. Specific primers around each IIS were designed to amplify the introns and the results indicated that introns in the same IIS varied in lengths, while terminal sequences were conserved. Our study showed that the process of intron loss happens via a series of successive steps, and each step could derive corresponding introns under intermediate states. Moreover, these results indicate that the mechanism of genomic deletion that occurs at DNA level can also lead to exact intron loss.
    Type of Medium: Online Resource
    ISSN: 0022-3646 , 1529-8817
    URL: Issue
    URL: Article
    DOI: 10.1111/jpy.2018.54.issue-1
    DOI: 10.1111/jpy.12605
    RVK:
    WA 15000
    Language: English
    Publisher: Wiley
    Publication Date: 2018
    detail.hit.zdb_id: 281226-5
    detail.hit.zdb_id: 1478748-9
    SSG: 12
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  • 9
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    Increased temperature benefits growth and photosynthetic performance of the sea ice diatom Nitzschia cf. neglecta (Bacillariophyceae) isolated from saroma lagoon, Hokkaido, Japan
    Wiley ; 2019
    In:  Journal of Phycology Vol. 55, No. 3 ( 2019-06), p. 700-713
    Details
    In: Journal of Phycology, Wiley, Vol. 55, No. 3 ( 2019-06), p. 700-713
    Abstract: During ice melt in spring, ice algae are released from the ice and could be exposed to variable temperatures and irradiances in surface water. Saroma Lagoon is an embayment with two inlets leading to the Sea of Okhotsk. With seasonal development of sea ice, its water temperature changes dramatically throughout the year. To investigate the living and photoprotective strategies of ice algae in such a coastal water system, we grew Nitzschia cf. neglecta , an ice diatom isolated from the sea ice of this lagoon, under irradiance levels of 30 and 100 μmol photons · m −2  · s −1 , and temperatures of 2°C and 10°C. Then the acclimated cells were exposed to high light in order to investigate the plasticity of their photosynthetic apparatus. At 10°C, cells grew faster and showed decreased susceptibility to high light. At 2°C, an immediate decrease in all pigment content upon exposure, as well as a higher cellular content of diatoxanthin was used to compensate for the more severe excitation stress. Highly efficient photoprotection was achieved through the diadinoxanthin‐diatoxanthin cycle‐dependent nonphotochemical quenching. While regulation through psb A and rbc L at the transcription level played a minor role in the response to high light stress at both temperatures. The wide tolerance to both temperature and light changes suggest that the thinning of sea ice and higher temperatures in a warmer world will lead to more intense blooms in Saroma Lagoon.
    Type of Medium: Online Resource
    ISSN: 0022-3646 , 1529-8817
    URL: Issue
    URL: Article
    DOI: 10.1111/jpy.2019.55.issue-3
    DOI: 10.1111/jpy.12846
    RVK:
    WA 15000
    Language: English
    Publisher: Wiley
    Publication Date: 2019
    detail.hit.zdb_id: 281226-5
    detail.hit.zdb_id: 1478748-9
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  • 10
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    Identification and Expression Analyses of the Nitrate Transporter Gene ( NRT 2 ) Family Among Skeletonema species (Bacillariophyceae)
    Wiley ; 2019
    In:  Journal of Phycology Vol. 55, No. 5 ( 2019-10), p. 1115-1125
    Details
    In: Journal of Phycology, Wiley, Vol. 55, No. 5 ( 2019-10), p. 1115-1125
    Abstract: High‐affinity nitrate transporters are considered to be the major transporter system for nitrate uptake in diatoms. In the diatom genus Skeletonema , three forms of genes encoding high‐affinity nitrate transporters ( NRT 2 ) were newly identified from transcriptomes generated as part of the marine microbial eukaryote transcriptome sequencing project. To examine the expression of each form of NRT 2 under different nitrogen environments, laboratory experiments were conducted under nitrate‐sufficient, ammonium‐sufficient, and nitrate‐limited conditions using three ecologically important Skeletonema species: S. dohrnii , S. menzelii, and S. marinoi . Primers were developed for each NRT 2 form and species and Q‐ RT ‐ PCR was performed. For each NRT 2 form, the three Skeletonema species had similar transcriptional patterns. The transcript levels of NRT 2:1 were significantly elevated under nitrogen‐limited conditions, but strongly repressed in the presence of ammonium. The transcript levels of NRT 2:2 were also repressed by ammonium, but increased 5‐ to 10‐fold under nitrate‐sufficient and nitrogen‐limited conditions. Finally, the transcript levels of NRT 2:3 did not vary significantly under various nitrogen conditions, and behaved more like a constitutively expressed gene. Based on the observed transcript variation among NRT 2 forms, we propose a revised model describing nitrate uptake kinetics regulated by multiple forms of nitrate transporter genes in response to various nitrogen conditions in Skeletonema . The differential NRT 2 transcriptional responses among species suggest that species‐specific adaptive strategies exist within this genus to cope with environmental changes.
    Type of Medium: Online Resource
    ISSN: 0022-3646 , 1529-8817
    URL: Issue
    URL: Article
    DOI: 10.1111/jpy.v55.5
    DOI: 10.1111/jpy.12896
    RVK:
    WA 15000
    Language: English
    Publisher: Wiley
    Publication Date: 2019
    detail.hit.zdb_id: 281226-5
    detail.hit.zdb_id: 1478748-9
    SSG: 12
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