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Ashley Garrill - One of the best experts on this subject based on the ideXlab platform.
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morphological and phylogenetic characterization of seven species of Vaucheria xanthophyceae including two new species from contrasting habitats in new zealand
Phytotaxa, 2014Co-Authors: Abishek Muralidhar, Ashley Garrill, Paul A Broady, Duncan P Macintyre, Michael D Wilcox, Phil M NovisAbstract:Vaucheria is a genus of yellow-green algae, the taxonomy of which is based on the morphology of antheridia and oogonia. Distribution of Vaucheria in New Zealand is poorly understood. Only two studies have investigated phylogenetic relationships in the genus world-wide and these omitted some of the diversity found in New Zealand. We identified seven species of Vaucheria based on morphology of their reproductive structures. Two were described as new species ( V . aestuarii and V . edaphica ), two were reported for the first time from New Zealand ( V . erythrospora and V . litorea ), one has been reported previously ( V . bursata ), and the identification of the remaining two was inconclusive ( Vaucheria cf. borealis and Vaucheria cf. conifera ). The genetic variation and phylogenetic position of these species were studied using phylogenetic analyses of rbc L sequences. These showed the existence of morphologically indistinguishable cryptic species complexes in sect. Corniculatae. Our results were mostly consistent with the current morphology-based sectional classification of the genus.
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an estuarine species of the alga Vaucheria xanthophyceae displays an increased capacity for turgor regulation when compared to a freshwater species
Journal of Phycology, 2013Co-Authors: Abishek Muralidhar, Phil M Novis, Paul A Broady, David A Collings, Ashley GarrillAbstract:Turgor regulation is the process by which walled organisms alter their internal osmotic potential to adapt to osmotic changes in the environment. Apart from a few studies on freshwater oomycetes, the ability of stramenopiles to turgor regulate has not been investigated. In this study, turgor regulation and growth were compared in two species of the stramenopile alga Vaucheria, Vaucheria erythrospora isolated from an estuarine habitat, and Vaucheria repens isolated from a freshwater habitat. Species were identified using their rbcL sequences and respective morphologies. Using a single cell pressure probe to directly measure turgor in Vaucheria after hyperosmotic shock, V. erythrospora was found to recover turgor after a larger shock than V. repens. Threshold shock values for this ability were >0.5 MPa for V. erythrospora and <0.5 MPa for V. repens. Recovery was more rapid in V. erythrospora than V. repens after comparable shocks. Turgor recovery in V. erythrospora was inhibited by Gd(3+) and TEA, suggesting a role for mechanosensitive channels, nonselective cation channels, and K(+) channels in the process. Growth studies showed that V. erythrospora was able to grow over a wider range of NaCl concentrations. These responses may underlie the ability of V. erythrospora to survive in an estuarine habitat and restrict V. repens to freshwater. The fact that both species can turgor regulate may indicate a fundamental difference between members of the Stramenopila, as research to date on oomycetes suggests they are unable to turgor regulate.
Robert A Andersen - One of the best experts on this subject based on the ideXlab platform.
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PHYLOGENETIC ANALYSIS OF 32 STRAINS OF Vaucheria (XANTHOPHYCEAE) USING THE rbcL GENE AND ITS TWO FLANKING SPACER REGIONS1
Journal of Phycology, 2002Co-Authors: Robert A Andersen, J. Craig BaileyAbstract:The complete rbcL gene was sequenced for 21 species and 32 strains of Vaucheria and for five other Xanthophyceae (Asterosiphon dichotomus (Kutzing) Rieth, Botrydium becharianum Vischer, B. cystosum Vischer, B. stoloniferum Mitra, Tribonema intermixtum Pascher). The psbA-rbcL spacer, upstream of the rbcL gene, and the RUBISCO spacer between the rbcL and rbcS genes were also completely sequenced for the Vaucheria strains and Asterosiphon. The psbA-rbcL spacer was the most variable region that was sequenced, and only the 3' end of the spacer could be aligned. Phylogenetic analyses (maximum parsimony, neighbor joining, and maximum likelihood) were conducted using the DNA sequence and the amino acid sequence for the rbcL gene, and a second analysis was conducted using a portion of the psbA-rbcL spacer + rbcL gene + RUBISCO spacer. All analyses showed that Vaucheria species formed monophyletic clades that corresponded with morphologically based subgeneric sections, including the section Racemosae. Species producing a gametophore (= fruiting branch, bearing both an antheridium and oogonium) formed a monophyletic clade in all analyses. The nongametophore species sometimes formed a monophyletic clade but other times formed a basal grade. Pair-wise comparisons of nucleotides and amino acids showed that for some species, numerous nucleotide changes resulted in relatively few amino acid changes. Consequently, phylogenetic analysis of the amino acids produced numerous trees, which in a strict consensus tree resulted in numerous polychotomies. An original strain of V. terrestris that was deposited in two culture collections over 25 years ago had identical sequences, suggesting no rapid change was occurring in the sequenced regions. Two strains of V. prona, isolated from Europe and North America, had identical sequences. Other species, for which two or more strains were examined, had different sequences. These results suggest that cryptic species complexes exist within Vaucheria because the rbcL gene is a conservative gene that is identical in other protists.
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MOLECULAR SYSTEMATICS OF THE XANTHOPHYCEAE
Journal of Phycology, 2000Co-Authors: J. C. Bailey, A. L. Mcelhinney, Robert A AndersenAbstract:Species belonging to the Xanthophyceae have traditionally been classified in six (or seven) orders corresponding to amoeboid, coccoid, filamentous, monadoid, palmelloid and siphonous lines of descent. We have determined plastid rbcL and nuclear 18S rRNA gene sequences for selected coccoid, filamentous and siphonous species. Phylogenetic trees inferred from these data indicate that the orders Mischococcales (coccoid) and Tribonematales (filamentous) are not monophyletic. Instead, our results indicate that coccoid and filamentous life forms have arisen independently in different xanthophyte lineages. Some coccoid and filamentous species are resolved as close allies. For example, in our analyses coccoid and filamentous species possessing bipartite cell walls (e.g., Bumilleria, Ophiocytium, Tribonema, Xanthonema) form a distinct and previously unrecognized lineage within the class. The phylogenetic positions of Asterosiphon, Botrydium and Vaucheria are not robustly resolved, but our data suggest that these siphonous xanthophytes probably do not form a monophyletic group. Our results imply that Vaucheria is only distantly related to other xanthophytes we have examined. Nucleotide sequence divergence values among Vaucheria species were found to be equal to, or greater than, those observed between other xanthophyte species that are classified in different families or orders. Furthermore, our trees do not always support the infrageneric system of classification for Vaucheria species, which is based primarily upon antheridial features.
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phylogenetic relationships of the raphidophyceae and xanthophyceae as inferred from nucleotide sequences of the 18s ribosomal rna gene
American Journal of Botany, 1997Co-Authors: Daniel Potter, Robert A AndersenAbstract:Some earlier studies suggested an evolutionary relationship between the Raphidophyceae (chloromonads) and Xantho- phyceae (yellow-green algae), whereas other studies suggested relationships with different algal classes or the Oomycete fungi. To evaluate the relationships, we determined the complete nucleotide sequences of the 18S ribosomal RNA gene from the raphidophytes Vacuolaria virescens, Chattonella subsalsa,and Heterosigma carterae,and the xanthophytes Vauch- eria bursata, Botrydium stoloniferum, Botrydiopsis intercedens,and Xanthonema debile. The results showed that the Xan- thophyceae were most closely related to the Phaeophyceae. A cladistic analysis of combined data sets (nucleotide sequences, ultrastructure, and pigments) suggested the Raphidophyceae are the sister taxon to the Phaeophyceae-Xanthophyceae clade, but the bootstrap value was low (40%). The raphidophyte genera were united with high (100%) bootstrap values, supporting a hypothesis based upon ultrastructural features that marine and freshwater raphidophytes form a monophyletic group. We examined the relationship between Vaucheria, a siphoneous xanthophyte alga, and the Oomycetes, and we confirmed that Vaucheria is a member of the class Xanthophyceae. Partial nucleotide sequences of the 18S rRNA gene from eight xantho- phytes (including Bumillariopsis filiformis, Heterococcus caespitiosus, and Mischococcus sphaerocephalus ) produce a phy- logeny that is not congruent with the current morphology-based classification scheme.
Hironao Kataoka - One of the best experts on this subject based on the ideXlab platform.
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quantitative analysis of tip growth phototropic responses and other blue light dependent photoresponses of Vaucheria
Methods of Molecular Biology, 2019Co-Authors: Hironao KataokaAbstract:The coenocytic tip-growing alga Vaucheria exhibits positive and negative phototropism, apical expansion, polarotropism, and branch induction from the illuminated region of the cell, all of which are caused by blue light. The bending response of Vaucheria is a blue light-mediated growth response. Differently from diffuse-growing cells or organs, the apical hemispherical dome of the Vaucheria cell is the site of not only maximum growth activity but also the site of blue light perception. Thence the phototropic response is initiated by the bulging mechanism: that is, a quick shift of the growth center to the adjacent subapical flank region. Since tip growth is driven by localized exocytosis, both phototropic bending and branch induction are considered to be closely related blue light-responses. Here I describe first how to prepare a highly useful culture medium for most freshwater algae, to establish unialgal and axenic culture of Vaucheria, and then describe several simple illumination systems using ordinary and/or inverted microscopes for the measurements of tip growth and for analyses of phototropism, polarotropism, and blue light-induced branching. Brief information is also included concerning the nature and function of aureochrome, the newly discovered, ochrophyte-specific blue light receptor. Aureochrome mediates blue light-induced branching, but its role in the phototropic response is still not elucidated.
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aureochrome a photoreceptor required for photomorphogenesis in stramenopiles
Proceedings of the National Academy of Sciences of the United States of America, 2007Co-Authors: Fumio Takahashi, Daisuke Yamagata, Mie Ishikawa, Yosuke Fukamatsu, Yasunobu Ogura, Masahiro Kasahara, Tomohiro Kiyosue, Munehiro Kikuyama, Masamitsu Wada, Hironao KataokaAbstract:A blue light (BL) receptor was discovered in stramenopile algae Vaucheria frigida (Xanthophyceae) and Fucus distichus (Phaeophyceae). Two homologs were identified in Vaucheria; each has one basic region/leucine zipper (bZIP) domain and one light–oxygen–voltage (LOV)-sensing domain. We named these chromoproteins AUREOCHROMEs (AUREO1 and AUREO2). AUREO1 binds flavin mononucleotide via its LOV domain and forms a 390-nm-absorbing form, indicative of formation of a cysteinyl adduct to the C(4a) carbon of the flavin mononucleotide upon BL irradiation. The adduct decays to the ground state in ≈5 min. Its bZIP domain binds the target sequence TGACGT. The AUREO1 target binding was strongly enhanced by BL treatment, implying that AUREO1 functions as a BL-regulated transcription factor. The function of AUREO1 as photoreceptor for BL-induced branching is elucidated through RNAi experiments. RNAi of AUREO2 unexpectedly induces sex organ primordia instead of branches, implicating AUREO2 as a subswitch to initiate development of a branch, but not a sex organ. AUREO sequences are also found in the genome of the marine diatom Thalassiosira pseudonana (Bacillariophyceae), but are not present in green plants. AUREOCHROME therefore represents a BL receptor in photosynthetic stramenopiles.
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aureochrome a photoreceptor required for photomorphogenesis in stramenopiles
Proceedings of the National Academy of Sciences of the United States of America, 2007Co-Authors: Fumio Takahashi, Daisuke Yamagata, Mie Ishikawa, Yosuke Fukamatsu, Yasunobu Ogura, Masahiro Kasahara, Tomohiro Kiyosue, Munehiro Kikuyama, Masamitsu Wada, Hironao KataokaAbstract:A blue light (BL) receptor was discovered in stramenopile algae Vaucheria frigida (Xanthophyceae) and Fucus distichus (Phaeophyceae). Two homologs were identified in Vaucheria; each has one basic region/leucine zipper (bZIP) domain and one light–oxygen–voltage (LOV)-sensing domain. We named these chromoproteins AUREOCHROMEs (AUREO1 and AUREO2). AUREO1 binds flavin mononucleotide via its LOV domain and forms a 390-nm-absorbing form, indicative of formation of a cysteinyl adduct to the C(4a) carbon of the flavin mononucleotide upon BL irradiation. The adduct decays to the ground state in ≈5 min. Its bZIP domain binds the target sequence TGACGT. The AUREO1 target binding was strongly enhanced by BL treatment, implying that AUREO1 functions as a BL-regulated transcription factor. The function of AUREO1 as photoreceptor for BL-induced branching is elucidated through RNAi experiments. RNAi of AUREO2 unexpectedly induces sex organ primordia instead of branches, implicating AUREO2 as a subswitch to initiate development of a branch, but not a sex organ. AUREO sequences are also found in the genome of the marine diatom Thalassiosira pseudonana (Bacillariophyceae), but are not present in green plants. AUREOCHROME therefore represents a BL receptor in photosynthetic stramenopiles.
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bimodal polarotropism of Vaucheria to polarized blue light parallel polarotropism at high fluence rate corresponds to negative phototropism
Journal of Plant Research, 2000Co-Authors: Hironao Kataoka, Fumio Takahashi, Tamotsu OotakiAbstract:(Xanthophyceae) exhibited cruciform polarotropism when they were grown under polarized white or blue light for several days. The coexistence of two groups of branches growing perpendicular and parallel to the electric vector (E-vector) resulted in cruciform polarotropic orientation. Such polarotropic bending was, however, not detected within 24 hr. As the fluence rate of polarized white or blue light increased, parallel orientation to the E-vector became dominant. Polarized red light produced exclusively perpendicular polarotropism. This shift in pattern was much obvious in V. terrestris sensu Gotz than V. sessllis and V. dichotoma. Since the photoperception is restricted to the tip of the apical dome and since this region receives maximum photons when the E-vector is at a right angle to the cell axis, Vaucheria becomes oriented normal to the E-vector as far as the fluence rate is optimum. The direction of growth is expected to change into parallel to the E-vector when the fluence rate is supraoptimum. The perpendicular (normal) and parallel polarotropism of Vaucheria, thus, correspond to positive and negative phototropism, respectively. Orientation of photoreceptor molecules is suggested to be predominantly parallel to the surface of the apical dome.
Katarzyna Chojnacka - One of the best experts on this subject based on the ideXlab platform.
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Bioaccumulation of Microelements in Seaweeds by Scanning Electron Microscopy with an Energy Dispersive X-Ray Analytical System and Inductively Coupled Plasma-Optical Emission Spectrometer
2020Co-Authors: Izabela Michalak, Katarzyna Chojnacka, Krzysztof Marycz, Katarzyna BasinskaAbstract:ABSTRACT In the present paper, bioaccumulation characteristics of Vaucheria sessilis were presented. The ability of macroalga to bioaccumulate Co(II) and Mn(II) ions was investigated using scanning electron microscopy with an energy dispersive X-ray analytical system (SEM-EDX) and inductively coupled plasma optical emission spectroscopy (ICP-OES). After two weeks of the experiment, macroalga accumulated about: 71.3 mg/g of Mn(II) and 41.9 mg/g of Co(II) ions. Micrographs performed by SEM proved, that bioaccumulation occurred. Metal ions were bound on the surface and in the interior of biomass. Mappings of cations showed, that in the case of the surface of biomass (biosorption), the elements constituted aggregations. In turn, in the case of the cross section (bioaccumulation) they were evenly distributed. The ability to bioaccumulate microelement ions by Vaucheria sessilis creates opportunities for its wide application. This macroalga constitute a perspective raw material for agricultural applications, not only due to pronounced microelement accumulation capabilities but also due to the content of bioactive compounds
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bioaccumulation of microelements in seaweeds by scanning electronmicroscopy with an energy dispersive x ray analytical system andinductively coupled plasma optical emission spectrometer
Research & Reviews: Journal of Botanical Sciences, 2016Co-Authors: Izabela Michalak, Katarzyna Chojnacka, Krzysztof Marycz, Katarzyna BasinskaAbstract:In the present paper, bioaccumulation characteristics of Vaucheria sessilis were presented. The ability of macroalga to bioaccumulate Co(II) and Mn(II) ions was investigated using scanning electron microscopy with an energy dispersive X-ray analytical system (SEM-EDX) and inductively coupled plasma optical emission spectroscopy (ICP-OES). After two weeks of the experiment, macroalga accumulated about: 71.3 mg/g of Mn(II) and 41.9 mg/g of Co(II) ions. Micrographs performed by SEM proved, that bioaccumulation occurred. Metal ions were bound on the surface and in the interior of biomass. Mappings of cations showed, that in the case of the surface of biomass (biosorption), the elements constituted aggregations. In turn, in the case of the cross section (bioaccumulation) they were evenly distributed. The ability to bioaccumulate microelement ions by Vaucheria sessilis creates opportunities for its wide application. This macroalga constitute a perspective raw material for agricultural applications, not only due to pronounced microelement accumulation capabilities but also due to the content of bioactive compounds.
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using sem edx and icp oes to investigate the elemental composition of green macroalga Vaucheria sessilis
The Scientific World Journal, 2014Co-Authors: Izabela Michalak, Krzysztof Marycz, Katarzyna Basinska, Katarzyna ChojnackaAbstract:The biomass of Vaucheria sessilis forms algal mats in many freshwaters. There is a need to find the method of algal biomass utilization. Vaucheria sessilis is a rich source of micro- and macronutrients and can be used as a soil amendment. In the paper, the elemental composition of enriched, via bioaccumulation process, macroalga was investigated. For this purpose, two independent techniques were used: scanning electron microscopy with an energy dispersive X-ray analytical system (SEMEDX) and inductively coupled plasma optical emission spectroscopy (ICP-OES). The biomass was exposed to two microelemental solutions, with Cu(II) and Zn(II) ions. After two weeks of the experiment, macroalga accumulated 98.5 mg of Zn(II) ions in 1 g of dry biomass and 68.9 mg g−1 of Cu(II) ions. Micrographs performed by SEM proved that bioaccumulation occurred. Metal ions were bound on the surface and in the interior of cells. Mappings of all cations showed that in the case of the surface of biomass (biosorption), the elements constituted aggregations and in the case of the cross section (bioaccumulation) they were evenly distributed. The algal biomass with permanently bound microelements can find an application in many branches of the industry (feed, natural fertilizers, etc.).
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Interactions of metal cations with anionic groups on the cell wall of the macroalga Vaucheria sp.
Engineering in Life Sciences, 2010Co-Authors: Izabela Michalak, Katarzyna ChojnackaAbstract:The aim of this article was to investigate the interactions of metal cations in aqueous solutions with the biomass of the freshwater macroalga Vaucheria sp. This problem is important when elaborating new applications of biosorption, e.g. the production of mineral feed additives for livestock from the biomass of algae enriched with microelement ions. Potentiometric titration was applied as a quick and cheap screening test to search for new efficient biosorbents. It revealed a variety of functional groups capable of cation exchange on the macroalgal surface, including carboxyl, phosphate, hydroxyl or amino groups. Fourier transform infrared spectroscopy on natural and chromium-loaded Vaucheria sp. confirmed that carboxyl groups played a dominant role in the biosorption. The study also showed that Ca(II), Na(I), K(I), and Mg(II) ions were released from the biomass after biosorption of Cu(II), Mn(II), Zn(II), and Co(II) ions, indicating that ion exchange was a key mechanism in the biosorption of metal ions by Vaucheria sp. biomass. It was noticed that the mass of the microelement cations bound by the macroalga was proportional to the total mass of light metal ions [Na(I), K(I), Ca(II), and Mg(II)] released from the biomass.
Samiaa Jamil Abdulwahid - One of the best experts on this subject based on the ideXlab platform.
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Algal Flora on some springs within Sherwan Mazn Subdistrict, Erbil–Kurdistan Region of Iraq, Iraq
2012Co-Authors: Samiaa Jamil AbdulwahidAbstract:This paper describes the first study of algal assemblages at 6 spring sites within Sherwan Mazn subdistrict between October 2011 to March 2012, with particular reference to abundance, distribution and periodicity were investigated in the samples collected. A total of 42 species was identified in 3 divisions, among them, 24 taxa was belonged of Bacillariophyta, 13 taxa was Chlorophyta and 5 taxa was Cyanophyta. The seasonality of algal flora was decreased at all springs in December and January. The dominant species among non-diatoms were, Oscillatoria, Lyngbya, Tribonema, Vaucheria and Spirogyra whereas among the diatoms were Navicula, Syndra, Gomphonema, and Nitzschia.
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Algal Flora on some springs within Sherwan Mazn Subdistrict, Erbil–Kurdistan Region of Iraq, Iraq
Society of Open Science, 2012Co-Authors: Samiaa Jamil AbdulwahidAbstract:This paper describes the first study of algal assemblages at 6 spring sites within Sherwan Mazn subdistrict between October 2011 to March 2012, with particular reference to abundance, distribution and periodicity were investigated in the samples collected. A total of 42 species was identified in 3 divisions, among them, 24 taxa was belong of Bacillariophyta, 13 taxa was Chlorophyta and 5 taxa was Cyanophyta. The seasonality of algal flora was decreased at all springs in December and January. The dominant species among non-diatoms were, Oscillatoria, Lyngbya, Tribonema, Vaucheria and Spirogyra whereas among the diatoms were Navicula, Syndra, Gomphonema, and Nitzschia
