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  • 1451.
    Östman, Carina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Molecular phylogeny of Ceriantharia (Cnidaria:Anthozoa) reveals non-monophyly of traditionally accepted familiesIn: Zoological Journal of the Linnean Society, ISSN 0024-4082, E-ISSN 1096-3642Article in journal (Refereed)
  • 1452.
    Östman, Carina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Nematocysts comparisons within some Hydrozoans, Scyphozoans and Anthozoans2015Conference paper (Refereed)
    Abstract [en]

    The largest nematocyst diversity occurs within Hydrozoa and the smallest diversity in Anthozoa. Isorhizas, present in Hydrozoa, Scyphozoa and Anthozoa, are the most diverse nematocyst group.  The functions of the isorhizas, their capsule shape and size, and their spine pattern can be similar or different within the three major taxonomic groups. As a rule, the more toxic nematocysts are larger than the less toxic ones. Generally, cnidarians feeding on large prey have larger, more toxic penetrating nematocysts with coarser and more pointed spines than animals feeding on small prey. The potent penetrating isorhizas with spherical capsules and hook-shaped spines along the tubule are larger in Physalia pelagica and Uvaria spp (Siphonophora, Hydrozoa) and in Cyanea capillata (Scyphozoa) compared to the smaller spherical isorhizas in the less toxic Aurelia aurita (Scyphozoa) and Tubularia spp (Hydrozoa). Cothylorhiza tuberculata and Casiopea xamancha (Scyphozoa) have still smaller spherical nematocysts. In addition to feeding on small zooplankton these two jellyfishes also get nutrition from symbiotic zooxanthellae. Spherical penetrating isorhiza are not present in Anthozoa. Penetrating isorhizas, specific for Anthozoa, have broad oval to narrow elongate capsules. Many penetrating isorhizas in Hydrozoa have also oval to elongated capsule but they differ in capsule shape and tubule pattern from those of Anthozoa. The largest isorhizas within C. capillata are not penetrators. These isorhizas entangle the prey with their long distal tubules armed with weak spines. Oval and elongated isorhizas, present in the cold water coral Lophelia pertusa and in the anemone Edwardsiella carnea (Anthozoa), might be used as primary attachment at settling for their larvae.  Entangling desmonemes, present in Tubularia spp, Halocordyle disticha and Hydractinia echinata, are specific for Hydrozoa. Other nematocysts, specific only in one of the three major taxonomic groups are the penetrating birophaloids in Siphonophores and stenoteles in Tubularia spp (Hydrozoa), and the penetrating b- and p-mastigophores and p-amastigophores in Anthozoa. The penetrating euryteles in H. echinata (Hydrozoa) are also present in Cyanea spp and A. aurita (Scyphozoa). 

  • 1453.
    Östman, Carina
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Larsson, Ann
    The cnidome and ultrastructural morphology of late planulae in Lophelia pertusa (Linnaeus, 1758) - with implications for settling competency2019In: Acta Zoologica (Stockholm), ISSN 0001-7272, E-ISSN 1463-6395, Vol. 00, p. 1-20Article in journal (Refereed)
  • 1454.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Borg, Fredrik
    Roat, Carsten
    Kultima, Jens Roat
    Wong, Sau Yu Grace
    Cnidae in the sea anemone Sagartiogeton viduatus (Muller, 1776) (Cnidaria, Anthozoa); A comparison to cnidae in the sea anemone Metridium senile (Linnaeus, 1761) (Cnidaria, Anthozoa)2013In: Acta Zoologica (Stockholm), ISSN 0001-7272, E-ISSN 1463-6395, Vol. 94, no 4, p. 392-409Article in journal (Refereed)
    Abstract [en]

    The cnidom of the sea anemone Sagartiogeton viduatus (Muller, 1776) is described from interference-contrast light micrographs (LMs) and scanning electron micrographs (SEMs). Special attention is given to nematocyst maturation, including the differentiation of the shaft into proximal and main regions as helical folding of the shaft wall proceeds. Comparisons are made with Metridium senile (Linnaeus, 1761), whose cnidom, with a few exceptions, is closely similar to that of S.viduatus. The two anemones possess b- and p-mastigophores, p-amastigophores, isorhizas and spirocysts. Although the majority of cnidae in S.viduatus is smaller than corresponding ones in M.senile, they are grouped into the same size classes as those of M.senile, namely small, medium and large. The main differences from M.senile cnidae are the followings: (1) Large acontia p-amastigophores are the largest nematocysts in S.viduatus. (2) They are noticeably larger than the large acontia b-mastigophores, and (3) they are separated from the p-amastigophores of M.senile by the sinusoid pattern of their U-shaped capsular matrix. (4) The large acontia b-mastigophores are microbasic and not mesobasic as in M.Senile, and (5) they do not produce darts. (6) Another difference from M.senile is the absence of catch-tentacle isorhizas.

  • 1455.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Friis Moller, Lene
    Sven Loven Marina Centrum, Göteborgs Universitet.
    Edwardsiella carnea (Gosse,1856) (Cnidaria, Actiniaria), the presumed adult seaanemone to the parasitic planula of the comb jelly Mnemiopsis leidy (Cnenophora)2013Conference paper (Other academic)
  • 1456.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Govindarajan, Annette
    Källström, Björn
    Selander, Erik
    Dahlgren, Thomas
    The highly toxic and cryptogenic clinging jellyfish Gonionemus sp. (Hydrozoa, Limnomedusae) on the Swedish west coast2019In: PeerJ, ISSN 2167-8359, E-ISSN 2167-8359, p. 1-18Article in journal (Refereed)
  • 1457.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Gustavsson, Frida
    Sea anemone nematocysts stored and transported in cnidosacs and cnidophage cells in nudibranchs2014In: A variety of interactions in marine environment: abstracts volume from 49th European Marine Biology Symposium, 2014, p. 100-101Conference paper (Other academic)
    Abstract [en]

    Abstract

    The nudibranchs Aeolidia papillosa (Linnaeus, 1759) and Aeolidiella glauca (Alder and Hancock, 1845) were fed with the sea anemones Metridium senile (Linnaeus, 1759) and the small anemone Sagartiogeton viduatus (Muller, 1776). Aeolid nudibranchs are known for storing nematocysts for self-defence from cnidarian preys in their numerous dorsal papillae or cerata. The nudibranchs possess a specific sorting mechanism to sequester these nematocysts. In each cerata tip a divertriculum of the gut opens into a cnidosac. Unfired nematocysts are stored in cnidophage cells inside the cnidosacs. One, two, three or more anemone nematocysts, of the same or of different types, could be present inside one cnidophage. Cnidophages, filled with nematocysts, were pressed out through the cnidosac pore. A. glauca and A. papillosa seemed to have a certain preference to store the most potent, large penetrating nematocysts; the large and medium p-amastigophores. They were relatively more numerous in some cnidosacs than in the anemones. Large p-amastigophores were often more abundant than large b-mastigophores, the most common acontia nematocysts.  Small nematocysts were more abundant in the nudibranch faeces compared to in the cnidosacs. The adhesive spirocysts, which are not useful for self-defence for the nudibranchs, were not found in the cnidosacs or in the cnidophages. Spirocysts were ejected with the faeces. Stored nematocysts might partly mirror which anemone structure the nudibranch had eaten. The larger nematocysts, from the acontia of the anemones, dominated in many cnidophage cells. Expect for in the acontia, medium b-mastigophores were the most common sea anemone nematocysts. In some cnidosacs medium b-mastigophores were the most abundant nematocysts. A. glauca cnidophages had the structure of an elongate bag, with an opening apically, through which nematocysts were ejected. The cnidophages were parallel oriented, with their apical end towards the longitudinal centre of the cnidosacs.  In its broad base a large nucleus and cytoplasm were present. The cnidophage narrowed from its broad base towards its apical end.  Inside the cnidophages the elongate, mostly closely packed anemone nematocysts were parallel oriented.  Their openings pointed all towards the apical cnidophage end with the opening. A. glauca cnidophages were slightly longer than the longest nematocysts of the favorite prey of the nudibranch, the S. viduatus anemone.  Large M. senile nematocysts, too long to fit inside the cnidophages of A. glauca, were ejected with the nudibranch faeces.  In light squash preparations of A. papillosa cerata, narrow strings of undamaged cnidophages could be pressed out of the cnidosac. A. papillosa cnidophages varied in size and shape, and the number of their stored nematocysts varied from 1- 5 up to 15-20.  No opening was visible in the apical cnidophage cell. Basally, the large nucleus and some cytoplasm were visible.  Inside the larger, most common cnidophages, nematocysts were closely packed, and their number was not possible to count, as long as the cnidophage was intact. Nematocysts too long to fit inside the smaller cnidophages had only their apical capsule ends inside the apical cnidophage. Their basal capsule ends, outside the cnidophage, were sometimes spread apart in the squash preparations.  However, the undischarged nematocyst capsules were still kept together by the apical cnidophage. The smallest cnidophages were of the size of the smallest A. papillosa nematocysts. Often they contained one single or 2-4 small nematocysts. The somewhat larger cnidophages contained 2-4, or more nematocysts of different sizes, the largest capsules with their basal end outside the cnidophage.  Empty cnidophage cells, presumably representing different developing stages, were of different sizes and irregular shapes. Some cnidophages were connected to each other. A big nucleus was visible in the cytoplasm. The cytoplasm surrounded the inner cell wall, leaving an inner canal free of substance. In mucus strings, excreted from the nudibranch anus, cnidophage cells filled with nematocysts, small packages of free nematocysts fitting in size into the cnidophages, and strings of closely packed, abundant, free nematocysts were present. Nematocysts in the packages and in the strings were parallel oriented, with their apical capsule end pointing in the same direction. In both A. glauca and A. papillosa cnidae, less useful in self-defence for the nudibranchs, were rejected with the nudibranch faeces. In some faeces discharged or undischarged spirocysts were by far the most abundant cnidae. Small nematocysts were more common in the faeces than larger nematocysts, except for the largest M. senile b-mastigophores in the faeces of A.glauca. Large p-amastigophores were rare or missing. Additional observations and conclusions: Immature nematocysts, early in development, were not found in the cnidosacs. Only a few elongate p-mastigophores, late in development, with the same capsule structure as mature ones were indentified here. Obviously most nematocysts did not complete their maturation in the cnidosacs as proposed by Grennwood and Mariscal (1984). The shape and size of the cnidophages seemed to have an important role in the transportation of nematocysts. No hydrozoan and scyphozoan nematocysts have been found in the cnidosacs. The rounded to oval size of these nematocysts might inhibit their storage in the cnidophages and cnidosacs. Hydrozoan and scyphozoan nematocysts were found in the nudibranch faeces. The sorting and rejecting mechanisms and the transportation of the nematocysts in the nudibranchs are still unknown but must be regarded as a masterpiece

    Sven Loven Marine centre, Fiskebäckskil, Sweden is acknowledged for laboratory facilities, prof. Per Ahlberg, for economic support, and Dr. Daniel Snitting for his criticism of the abstract, both from EBC, Uppsala, University Sweden.

     

  • 1458.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organism Biology, Evolution and Developmental Biology.
    Kultima, Jens Roat
    Roat, Carsten
    Tentacle cnidae of the sea anemone Metridium senile (Linnaeus, 1761) (Cnidaria Anthozoa)2010In: Scientia Marina, ISSN 0214-8358, E-ISSN 1886-8134, Vol. 74, no 3, p. 511-521Article in journal (Refereed)
    Abstract [en]

    Tentacle cnidae of Metridium senile (Linnaeus, 1761) were examined by light microscopy. In addition to spirocysts, feeding-tentacles had 3 nematocyst categories grouped into medium and small size-classes, including 5 types. Spirocysts dominated, especially distally, followed by medium b-mastigophores. The density of cnidae decreased towards the tentacle base. Early cnidoblasts were numerous on the tentacle tip. Late cnicloblasts appeared in a moderate number on the mid-tentacle. Catch-tentacles, found in two Metridium specimens, had a maturity gradient of isorhizas and gland cells along their length. Their tip had two distinct types of mature isorhizas in great numbers and large gland cells, but lacked spirocysts. Mature isorhizas and gland cells decreased in number towards the tentacle base. On the mid-tentacle differentiating ages of isorhizas were numerous. Ordinary feeding-tentacle cnidae, abundant at the tentacle base, decreased in number distally along the tentacle.

  • 1459.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organism Biology, Evolution and Developmental Biology.
    Kultima, Jens Roat
    Uppsala University.
    Roat, Carsten
    Rundblom, Karl
    Uppsala University.
    Acontia and mesentery nematocysts of the sea anemone Metridium senile (Linnaeus, 1761) (Cnidaria Anthozoa)2010In: Scientia Marina, ISSN 0214-8358, E-ISSN 1886-8134, Vol. 74, no 3, p. 483-497Article in journal (Refereed)
    Abstract [en]

    Acontia and mesentery nematocysts of Metridium senile (Linnaeus, 1761) are described from interference-contrast light micrographs (LMs) and scanning electron micrographs (SEMs). The acontia have 2 nematocyst categories grouped into small, medium and large size-classes, including 5 types: of these, large b-mastigophores and large p-amastigophores are the largest and most abundant. Mesenterial tissues, characterised by small p-mastigophores and medium p-amastigophores, have 3 nematocyst categories grouped as small and medium, including 6 types. Attention is given to nematocyst maturation, especially to the differentiation of the shaft into proximal and main regions as helical folding of the shaft wall proceeds. Groups of differentiating nematoblasts occur along acontia, and near the junction between acontia and mesenterial filaments. Nematoblasts are sparsely found throughout mesenterial tissues.

  • 1460.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organism Biology, Evolution and Developmental Biology.
    Kultima, Jens Roat
    Wong, Sau Yu Grace
    Dart formation in nematocysts of the sea anemone Metridium senile (Linnaeus, 1761) (Cnidaria Anthozoa)2010In: Scientia Marina, ISSN 0214-8358, E-ISSN 1886-8134, Vol. 74, no 3, p. 499-510Article in journal (Refereed)
    Abstract [en]

    In examining large acontia b-mastigophore and p-amastigophore nematocysts of the sea anemone Metridium senile (Linnaeus, 1761) darts were observed by interference-contrast light microscopy (LM) and scanning electron microscopy (SEM). The darts consist of closely packed spines detached from the shafts, still in three helical rows. Their spines form a hollow cylinder with a sharp tip and indented base, its width similar to that of an undischarged shaft but varying in length. b-mastigophore darts were more common than those of p-mastigophores and many were longer.

  • 1461.
    Östman, Carina
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Strömberg, Susanna M
    The cnidome and internal morphology of Lophelia pertusa (Linnaeus, 1758) (Cnidaria, Anthozoa)2017In: Acta Zoologica (Stockholm), ISSN 0001-7272, E-ISSN 1463-6395, Vol. 98, p. 191-213Article in journal (Refereed)
    Abstract [en]

    The cnidome of the scleractinian cold-water coral Lophelia pertusa (Linnaeus, 1758, syn. Lophohelia prolifera) was described by Carlgren in 1940. Due to a renewed interest in the cnidae of L. pertusa, specifically comparisons of adult and larval cnidae and their functions, we now redescribe the cnidome from material collected at the Tisler reef in Norway, close to Carlgren's collection site at Saekken (Sweden). Cnidae from column, tentacles, actinopharynx, mesenterial filaments and acontia were investigated. Fresh tissue preparations were compared to histological preparations of decalcified polyps to verify the presence of cnidocysts and secretory cells, and their composition and organization within tissues. The cnidome included microbasic b-mastigophores, microbasic and mesobasic p-mastigophores, holotrichous isorhizas and spirocysts. The nematocyst type cnidae (b-, p-mastigophores, isorhizas) appeared in different size classes with different distributions within the tissue. Spirocysts were highly variable in shape and size, without distinct size classes. In addition, developing stages of cnidae were documented, with new observations on the succession of p-mastigophore shaft development. The present observations were in general congruent with the cnidocyst descriptions from L. prolifera made by Carlgren; however, a tiny cnida, possibly of isorhiza type, has been added. Finally, the use of the term acontia is discussed.

  • 1462.
    Övernäs, Elin
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organism Biology, Physiological Botany.
    Characterisation of Members of the HD-Zip I and DREB/ERF Transcription Factor Families and their Functions in Plant Stress Responses2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Plants have to adapt to various environmental conditions. In comparison with other eukaryotes, plant genomes encode relatively many transcription factors, and have families of transcription factors only found in plants, two such are the large AP2/ERF (APETALA2/Ethylene Responsive Factor) and HD-Zip (Homeodomain leucine zipper) families. Members of these families play roles in plant development, responses to stress and other environmental stimuli. This thesis describes the functions of members of both these families. Two AP2/ERF proteins of the DREB/ERF (Drought Responsive Element Binding/Ethylene Responsive Factor) subfamily, AtERF38 and AtERF39 show a negative effect on growth in transgenic over-expression lines. They are regulated by stress and confer stress tolerance, which suggests a function as negative growth regulators during stress. The 14 Oryza sativa (rice) HD-Zip I genes were described and a phylogenetic analysis of the HD-Zip I genes in Arabidopsis thaliana, rice and Craterostigma plantagineum defined four clades that were conserved between mono and dicots, but also showed that four clades had most likely been lost in either lineage. The phylogeny was supported by conserved intron/exon patterning and the duplication history of the rice genome. The expression patterns in different organs indicate a non-conserved regulation of genes within and between clades. Drought stress regulation was conserved within two clades, but not between the clades. Further analysis on the function of four HD-Zip I genes in Arabidopsis, ATHB5, -6, -7 and -12 showed an involvement in the transcriptional regulation of ABA receptors and signalling components. These are the first described direct target genes for ATHB7 and ATHB12. It was also shown that there exists a direct cross-regulation between these four HD-Zips. The effect of ATHB5, -6, -7 and -12 would be as negative regulators of ABA signalling, desensitising the plant to constant levels of ABA, and enabling sensitivity to changes in stress level.

    List of papers
    1. Two AP2 transcription factors, AtERF38 and AtERF39, have similar function but are differently regulated in ABA and stress responses.
    Open this publication in new window or tab >>Two AP2 transcription factors, AtERF38 and AtERF39, have similar function but are differently regulated in ABA and stress responses.
    (English)Manuscript (preprint) (Other academic)
    Research subject
    Physiological Botany
    Identifiers
    urn:nbn:se:uu:diva-129183 (URN)
    Available from: 2010-08-09 Created: 2010-08-06 Last updated: 2010-08-09
    2. A genome-wide survey of HD-Zip genes in rice and analysis of drought-responsive family members
    Open this publication in new window or tab >>A genome-wide survey of HD-Zip genes in rice and analysis of drought-responsive family members
    Show others...
    2008 (English)In: Plant Molecular Biology, ISSN 0167-4412, E-ISSN 1573-5028, Vol. 66, no 1-2, p. 87-103Article in journal (Refereed) Published
    Abstract [en]

    The homeodomain leucine zipper (HD-Zip) genes encode transcription factors that have diverse functions in plant development and have often been implicated in stress adaptation. The HD-Zip genes are the most abundant group of homeobox (HB) genes in plants and do not occur in other eukaryotes. This paper describes the complete annotation of the HD-Zip families I, II and III from rice and compares these gene families with Arabidopsis in a phylogeny reconstruction. Orthologous pairs of rice and Arabidopsis HD-Zip genes were predicted based on neighbour joining and maximum parsimony (MP) trees with support of conserved intron-exon organization. Additionally, a number of HD-Zip genes appeared to be unique to rice. Searching of EST and cDNA databases and expression analysis using RT-PCR showed that 30 out of 31 predicted rice HD-Zip genes are expressed. Most HD-Zip genes were broadly expressed in mature plants and seedlings, but others showed more organ specific patterns. Like in Arabidopsis and other dicots, a subset of the rice HD-Zip I and II genes was found to be regulated by drought stress. We identified both drought-induced and drought-repressed HD-Zip genes and demonstrate that these genes are differentially regulated in drought-sensitive versus drought-tolerant rice cultivars. The drought-repressed HD-Zip family I gene, Oshox4, was selected for promoter-GUS analysis, showing that drought-responsiveness of Oshox4 is controlled by the promoter and that Oshox4 expression is predominantly vascular-specific. Loss-of-function analysis of Oshox4 revealed no specific phenotype, but overexpression analysis suggested a role for Oshox4 in elongation and maturation processes.

    Keywords
    homeodomain-leucine zipper, homeobox, rice, Arabidopsis, drought
    National Category
    Biological Sciences
    Identifiers
    urn:nbn:se:uu:diva-13056 (URN)10.1007/s11103-007-9255-7 (DOI)000251656400007 ()17999151 (PubMedID)
    Available from: 2008-05-28 Created: 2008-05-28 Last updated: 2017-12-11Bibliographically approved
    3. The homeodomain-leucine zipper (HD-Zip) class I transcription factors ATHB7 and ATHB12 modulate abscisic acid signalling by regulating protein phosphatase 2C and abscisic acid receptor gene activities
    Open this publication in new window or tab >>The homeodomain-leucine zipper (HD-Zip) class I transcription factors ATHB7 and ATHB12 modulate abscisic acid signalling by regulating protein phosphatase 2C and abscisic acid receptor gene activities
    Show others...
    2012 (English)In: Plant Molecular Biology, ISSN 0167-4412, E-ISSN 1573-5028, Vol. 80, no 4-5, p. 405-418Article in journal (Refereed) Published
    Abstract [en]

    Plants perceiving drought activate multiple responses to improve survival, including large-scale alterations in gene expression. This article reports on the roles in the drought response of two Arabidopsis thaliana homeodomain-leucine zipper class I genes; ATHB7 and ATHB12, both strongly induced by water-deficit and abscisic acid (ABA). ABA-mediated transcriptional regulation of both genes is shown to depend on the activity of protein phosphatases type 2C (PP2C). ATHB7 and ATHB12 are, thus, targets of the ABA signalling mechanism defined by the PP2Cs and the PYR/PYL family of ABA receptors, with which the PP2C proteins interact. Our results from chromatin immunoprecipitation and gene expression analyses demonstrate that ATHB7 and ATHB12 act as positive transcriptional regulators of PP2C genes, and thereby as negative regulators of abscisic acid signalling. In support of this notion, our results also show that ATHB7 and ATHB12 act to repress the transcription of genes encoding the ABA receptors PYL5 and PYL8 in response to an ABA stimulus. In summary, we demonstrate that ATHB7 and ATHB12 have essential functions in the primary response to drought, as mediators of a negative feedback effect on ABA signalling in the plant response to water deficit.

    Keywords
    ABA, ABA receptors, Drought stress response, HD-Zip, PP2C, SnRK2
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:uu:diva-129184 (URN)10.1007/s11103-012-9956-4 (DOI)000312133800004 ()
    Available from: 2010-08-09 Created: 2010-08-06 Last updated: 2017-12-12Bibliographically approved
    4. Involvement of the Arabidopsis HD-Zip genes ATHB5 and ATHB6 in ABA responses
    Open this publication in new window or tab >>Involvement of the Arabidopsis HD-Zip genes ATHB5 and ATHB6 in ABA responses
    (English)Manuscript (preprint) (Other academic)
    Identifiers
    urn:nbn:se:uu:diva-129185 (URN)
    Available from: 2010-08-09 Created: 2010-08-06 Last updated: 2016-04-25
  • 1463.
    Övernäs, Elin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organism Biology, Physiological Botany.
    Sundås Larsson, Annika
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organism Biology, Physiological Botany.
    Söderman, Eva
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organism Biology, Physiological Botany.
    Two AP2 transcription factors, AtERF38 and AtERF39, have similar function but are differently regulated in ABA and stress responses.Manuscript (preprint) (Other academic)
  • 1464.
    Övernäs, Elin
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Physiological Botany.
    Valdés, Ana Elisa
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Physiological Botany.
    Johansson, Henrik
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Physiological Botany.
    Engström, Peter
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Physiological Botany.
    Involvement of the Arabidopsis HD-Zip genes ATHB5 and ATHB6 in ABA responsesManuscript (preprint) (Other academic)
  • 1465.
    Žigaitė, Živilė
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Goujet, Daniel
    National Museum of Natural History, France.
    Karatajute-Talimaa, Valentina
    Vilnius University.
    New vertebrate assemblages from the Andrée Land Group, Spitsbergen, and their biostratigraphic significance2010In: Programme and Abstracts: The Palaeontological Association: 54th Annual Meeting 17th–20th December 2010: Ghent University, 2010, p. 80-81Conference paper (Other academic)
    Abstract [en]

    The Lower and Middle Devonian successions of Spitsbergen provide excellent examples of vertebrate biostratigraphy applied to sedimentary basin analysis. A number of previous works on the Red Bay Group (Lochkovian, Lower Devonian) made a notable study of the earliest Devonian vertebrate record, and their use in biostratigraphy. Our current study concerns the Lower to Middle Devonian of the Andrée Land Group, which comprises the Wood Bay Formation, spanning from Pragian to Emsian in age, and the Grey Hoek Formation, representing the Eifelian. It consists of thick layers of terrigenous sediments, the stratigraphy is largely based on the lithofacies.

    Two new thelodont assemblages are considered to represent different depostional phases of the late Lower - early Middle Devonian of the Andrée Land Group. The first, older assemblage comprises turiinid, talivaliid, and furcacaudid thelodonts, and identifies the lower Wood Bay Formation. The second, younger assemblage is prevailed by the talivaliid thelodont <i>Amaltheolepis winsnesi</i>, and is characteristic for the upper Wood Bay Fm., as well as the lower Grey Hoek Fm. The recognition of these two new thelodont assemblages allows us to precise the relative age of the Lower – Middle Devonian strata.

  • 1466.
    Žigaitė, Živilė
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Karatajūtė-Talimaa, Valentina
    Blieck, Alain
    Vertebrate microremains from the Lower Silurian of Siberia and Central Asia: palaeobiodiversity and palaeobiogeography2011In: Journal of Micropalaeontology, ISSN 0262-821X, E-ISSN 2041-4978, Vol. 30, p. 97-106Article in journal (Refereed)
    Abstract [en]

    The biostratigraphic and palaeogeographical distributions of early vertebrate microfossils from a number of Lower Silurian localities in northwestern Mongolia, Tuva and southern Siberia were reviewed. Vertebrate microremains showed high taxonomic diversity, comprising acanthodians, chondrichthyans, putative galeaspids, heterostracans, mongolepids, tesakoviaspids, thelodonts and possible eriptychiids. The majority of taxa have lower stratigraphic levels of occurrence compared to other Silurian palaeobiogeographical provinces, such as the European-Russian or Canadian Arctic. Vertebrate microremains are numerous within the samples, which may indicate warm-water low-latitude palaeobasins with rich shelf faunas. This disagrees with the recent interpretations of the territory as a northern high-latitude Siberian palaeocontinent. The palaeobiogeographical distribution of vertebrate taxa indicates an endemic palaeobiogeographical province of connected epeiric palaeoseas with external isolation during the early Silurian. In previous works separation between Tuvan and Siberian palaeobiogeographical provinces has been suggested. After careful revision of the vertebrate microfossil record of the region, we find that differences in a few vertebrate taxa do not provide not strong enough evidence to reliably distinguish these provinces. We therefore dispute the hypothesis of two biogeographical provinces in the early Silurian of the Siberian palaeocontinent, and propose a single unified Siberian-Tuvan palaeobiogeographical province.

  • 1467.
    Žigaitė, Živilė
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Pérez-Huerta, Alberto
    University of Alabama, USA.
    Jeffries, Teresa
    Natural History Museum, London, UK.
    Kear, Benjamin
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    REE compositions in fossil vertebrate dental tissues – key to biomineral preservation2011In: The Palaeontological Association Newsletter, 2011Conference paper (Other academic)
    Abstract [en]

    Rare earth element (REE) abundances have been measured in a number of Palaeozoic and Mesozoic vertebrate hard tissues (teeth and dermoskeleton) using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Fossil vertebrate analysed comprise scales and tesserae of Silurian and Devonian thelodonts, chondrichthyans, galeaspids, mongolepids, spines of acanthodians, as well as teeth of Cretaceous lungfish and marine reptiles.

    Pre-evaluation of fossil preservation level has been made by semi-quantitative spot geochemistry analyses on fine polished teeth and scale thin sections, using energy dispersive X-ray spectroscopy (EDS). Silicification of bioapatite, together with elevated heavy element concentrations corresponded to fossil tissue structure and colour alteration. Stable oxygen isotope measurements (δ<sup>18</sup>O) of bulk biomineral have been conducted in parallel, generally yielding lower heavy oxygen values in stronger alterated teeth and scales. Clear distinction in REE concentrations was observed between dentine and enamel of Cretaceous plesiosaurs, suggesting enamel to be more geochemically resistant to diagenetic overprint.

  • 1468.
    Žigaitė, Živilė
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Pérez-Huerta, Alberto
    Department of Geological Sciences, University of Alabama.
    Jeffries, Teresa
    Mineralogy Department, Natural History Museum, London.
    Kear, Benjamin P
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Palaeobiology.
    Blom, Henning
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Geochemistry of fossilised dental remains: a key to palaeobiology and palaeoenvironment2011In: Abstracts: The 2nd Wiman meeting : Carl Wiman's Legacy: 100 years of Swedish Palaeontology : Uppsala 17–18 November 2011 / [ed] Benjamin P. Kear, Michael Streng, 2011, p. 24-25Conference paper (Other academic)
  • 1469.
    Žigaitė, Živilė
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Organismal Biology, Evolution and Developmental Biology.
    Pérez-Huerta, Alberto
    University of Alabama, USA.
    Joachimski, Michael M.
    University of Erlangen-Nürnberg.
    Lehnert, Oliver
    University of Erlangen-Nürnberg.
    The 18O/16O ratio in vertebrate biogenic apatite as a proxy to Palaeozoic seawater temperatures2011In: Geophysical Research Abstracts: Vol. 13, EGU2011-11965, Göttingen: Copernicus , 2011Conference paper (Other academic)
27282930 1451 - 1469 of 1469
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