Pandorina

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 513 Experts worldwide ranked by ideXlab platform

Annette W. Coleman - One of the best experts on this subject based on the ideXlab platform.

  • FishPond revisited: how can microalgae be perennials?
    Phycologia, 2004
    Co-Authors: Annette W. Coleman
    Abstract:

    Abstract Any understanding of the role of sexual reproduction vs other life cycle stages in biogeography requires some estimate of their roles in nature, preferably with some empirical data. For organisms such as microalgae, essentially no such data are available. Stages of the life cycle have been elucidated for a great many microeukaryotes, but only presumptions are possible concerning their importance for distribution in nature. This hiatus results in part from an inability to identify precisely a particular algal strain. With the appearance of molecular techniques, this may be overcome. We present here an example of the utility of DNA sequences to assist in evaluating the possible role of the vegetative stage in overwintering. In brief, as a result of DNA sequence information it was possible to recognize that a population of Pandorina morum indigenous to a pond over a period of 20 years, and thought originally to be either diverse or sterile, was in fact fertile but present as only one mating type thr...

  • biogeography and speciation in the Pandorina volvulina chlorophyta superclade
    Journal of Phycology, 2001
    Co-Authors: Annette W. Coleman
    Abstract:

    Mating affinity, nuclear rDNA internal transcribed spacer (ITS) sequence, and geographic distribution of more than 100 isolates of Pandorina, Volvulina, and Yamagishiella were determined. Comparative analysis of ITS sequences reaffirmed the unity of Pandorina morum and its separation from all other species of Volvocaceae except those of Volvulina. This latter genus, represented by four species, appears to represent only morphological variants of several P. morum subclades. The P. morum clade (including also additional species such as P. smithii and P. colemaniae) encompasses an evolutionary span, as determined by comparison of ITS, greater than either of the multispecies genera Gonium or Eudorina. There are at least 30 Pandorina/Volvulina syngens, sexually isolated groups, so far as can be determined, among the current collection of strains. In addition, as in other volvocacaean genera, two clones are homothallic, capable of forming zygotes within a genetic clone. The existence of so many syngens suggests that considerable evolutionary diversification of the genes controlling gamete compatibility and intercross survival has occurred, unaccompanied by significant morphological change. Within each syngen, genetic distance increases with geographic distance between collection sites. At least half of the isolates studied must have been introduced northward since the Pleistocene. Although we probably know more about characters in this group of algae than any other algal group, in part because they are so easy to culture, we are still largely ignorant of what circumscribes their niche in nature. The study of all these organisms, distributed throughout the world presumably by the activities of shorebirds, emphasizes the evolutionary role of mating genes in the inevitable formation of new genetically isolated subclades in these eukaryotes and provides initial data on their rate of appearance versus their rate of distribution over the earth.

  • BIOGEOGRAPHY AND SPECIATION IN THE Pandorina/VOLVULINA (CHLOROPHYTA) SUPERCLADE
    Journal of Phycology, 2001
    Co-Authors: Annette W. Coleman
    Abstract:

    Mating affinity, nuclear rDNA internal transcribed spacer (ITS) sequence, and geographic distribution of more than 100 isolates of Pandorina, Volvulina, and Yamagishiella were determined. Comparative analysis of ITS sequences reaffirmed the unity of Pandorina morum and its separation from all other species of Volvocaceae except those of Volvulina. This latter genus, represented by four species, appears to represent only morphological variants of several P. morum subclades. The P. morum clade (including also additional species such as P. smithii and P. colemaniae) encompasses an evolutionary span, as determined by comparison of ITS, greater than either of the multispecies genera Gonium or Eudorina. There are at least 30 Pandorina/Volvulina syngens, sexually isolated groups, so far as can be determined, among the current collection of strains. In addition, as in other volvocacaean genera, two clones are homothallic, capable of forming zygotes within a genetic clone. The existence of so many syngens suggests that considerable evolutionary diversification of the genes controlling gamete compatibility and intercross survival has occurred, unaccompanied by significant morphological change. Within each syngen, genetic distance increases with geographic distance between collection sites. At least half of the isolates studied must have been introduced northward since the Pleistocene. Although we probably know more about characters in this group of algae than any other algal group, in part because they are so easy to culture, we are still largely ignorant of what circumscribes their niche in nature. The study of all these organisms, distributed throughout the world presumably by the activities of shorebirds, emphasizes the evolutionary role of mating genes in the inevitable formation of new genetically isolated subclades in these eukaryotes and provides initial data on their rate of appearance versus their rate of distribution over the earth.

  • THE FISH POND EXPERIMENT: CHAPTER TWO
    Journal of Phycology, 2000
    Co-Authors: Annette W. Coleman
    Abstract:

    Forty years ago, after 1 1/2 years of weekly surveys, a Baltimore fishpond was inoculated with three identifiable clones of Pandorina morum. The results of subsequent recollection attempts are published in Amer. Naturalist 118:761 (1981). More recently, molecular analyses have permitted characterization of the P. morum population that was endemic to the pond. The results, and their comparison with those from other P. morum sites, challenge some longstanding assumptions concerning the importance of various lifehistory stages to the introduction and maintenance of algal populations in temperate freshwater locales.

  • Infraspecific phylogeny of Pandorina morum (Volvocales, Chlorophyta) inferred from molecular, biochemical and traditional data
    European Journal of Phycology, 1999
    Co-Authors: Michael Schagerl, David G. Angeler, Annette W. Coleman
    Abstract:

    Molecular phylogenetic relationships among sexually isolated subpopulations (syngens) of the morphologically defined volvocacean flagellate Pandorina morum (O. F. Muller) Bory are inferred from sequences of the internal transcribed spacer regions (ITS-1 and ITS-2) of the nuclear ribosomal DNA repeats. The resolved phylogenetic lines are composed of strains with very similar sets of traditional characters, such as zygote aggregation pattern, chromosome number and cell division timing, and are correlated with the distribution pattern of the xanthophyll loroxanthin [(3R,3′R,6′R)-β,ϵ-carotene-3,19,3′-triol]. Thus, loroxanthin, a phylogenetic character within the Volvocales, is also of value at the infraspecific level in P. morum, a morphologically uniform species complex, within the Volvocales.

Hisayoshi Nozaki - One of the best experts on this subject based on the ideXlab platform.

  • Distribution of the Sex-Determining Gene MID and Molecular Correspondence of Mating Types within the Isogamous Genus Gonium (Volvocales, Chlorophyta)
    2016
    Co-Authors: Takashi Hamaji, Patrick J. Ferris, Ichiro Nishii, Yoshiki Nishimura, Hisayoshi Nozaki
    Abstract:

    Background: Isogamous organisms lack obvious cytological differences in the gametes of the two complementary mating types. Consequently, it is difficult to ascertain which of the two mating types are homologous when comparing related but sexual isolated strains or species. The colonial volvocalean algal genus Gonium consists of such isogamous organisms with heterothallic mating types designated arbitrarily as plus or minus in addition to homothallic strains. Homologous molecular markers among lineages may provide an ‘‘objective’ ’ framework to assign heterothallic mating types. Methodology/Principal Findings: Using degenerate primers designed based on previously reported MID orthologs, the ‘‘master regulator’ ’ of mating types/sexes in the colonial Volvocales, MID homologs were identified and their presence/ absence was examined in nine strains of four species of Gonium. Only one of the two complementary mating types in each of the four heterothallic species has a MID homolog. In addition to heterothallic strains, a homothallic strain of G. multicoccum has MID. Molecular evolutionary analysis suggests that MID of this homothallic strain retains functional constraint comparable to that of the heterothallic strains. Conclusion/Significance: We coordinated mating genotypes based on presence or absence of a MID homolog, respectively, in heterothallic species. This scheme should be applicable to heterothallic species of other isogamous colonial Volvocales including Pandorina and Yamagishiella. Homothallism emerged polyphyletically in the colonial Volvocales, although it

  • New “missing link” genus of the colonial volvocine green algae gives insights into the evolution of oogamy
    BMC Evolutionary Biology, 2014
    Co-Authors: Hisayoshi Nozaki, Toshihiro K Yamada, Ryo Matsuzaki, Fumio Takahashi, Takashi Nakada
    Abstract:

    Background The evolution of oogamy from isogamy, an important biological event, can be summarized as follows: morphologically similar gametes (isogametes) differentiated into small “male” and large “female” motile gametes during anisogamy, from which immotile female gametes (eggs) evolved. The volvocine green algae represent a model lineage to study this type of sex evolution and show two types of gametic unions: conjugation between isogametes outside the parental colonies (external fertilization during isogamy) and fertilization between small motile gametes (sperm) and large gametes (eggs) inside the female colony (internal fertilization during anisogamy and oogamy). Although recent cultural studies on volvocine algae revealed morphological diversity and molecular genetic data of sexual reproduction, an intermediate type of union between these two gametic unions has not been identified. Results We identified a novel colonial volvocine genus, Colemanosphaera , which produces bundles of spindle-shaped male gametes through successive divisions of colonial cells. Obligately anisogamous conjugation between male and female motile gametes occurred outside the female colony (external fertilization during anisogamy). This new genus contains 16- or 32-celled spheroidal colonies similar to those of the volvocine genera Yamagishiella and Eudorina . However, Colemanosphaera can be clearly distinguished from these two genera based on its sister phylogenetic position to the enigmatic flattened colonial volvocine Platydorina and external fertilization during anisogamy. Two species of Colemanosphaera were found in a Japanese lake; these species are also distributed in European freshwaters based on a published sequence of an Austrian strain and the original description of Pandorina charkowiensis from Ukraine. Conclusions Based on phylogeny and morphological data, this novel genus exhibits a missing link between Platydorina and the typical spheroidal colonial volvocine members such as Pandorina or Yamagishiella . Considering the external obligate anisogamy, oogamy evolution may have been preceded by the transition from external to internal fertilization during anisogamy within the volvocine green algae.

  • morphology and phylogeny of eudorina minodii chodat nozaki et krienitz comb nov volvocales chlorophyta from germany
    European Journal of Phycology, 2001
    Co-Authors: Hisayoshi Nozaki, Lothar Krienitz
    Abstract:

    Morphology, sexual reproduction and phylogeny of a colonial green alga collected from Germany were studied in culture. Light and electron microscopy of the gelatinous (extracellular) matrix of vegetative colonies, the absence of obligately somatic cells, and the anisogamous sexual reproduction with sperm packets in this alga indicated that it is assignable to the genus Eudorina. This German alga was similar to E. elegans Ehrenberg in its multiple pyrenoids of nearly identical size and almost identical sized vegetative cells in the colony, but differed from it in having a prominent tubular structure (flagellar sheath) surrounding each flagellum in the gelatinous matrix of the vegetative colonies. Sexual reproduction was homothallic and dioecious. On the other hand, the vegetative morphology agreed well with that of Pandorina minodii Chodat with regard to multiple pyrenoids and the prominent flagellar sheaths. Thus, a new combination, Eudorina minodii (Chodat) Nozaki et Krienitz, is proposed. Molecular phyl...

  • Morphology and evolution of sexual reproduction in the Volvocaceae (Chlorophyta)
    Journal of Plant Research, 1996
    Co-Authors: Hisayoshi Nozaki
    Abstract:

    Morphological features of sexual reproduction in the Volvocaceae are reviewed, focusing particularly on gametic union and zygote gemination. Both of the two conjugating gametes of the isogamous genera Pandorina, Volvulina and Yamagishiella bear a tubular mating structure (mating papilla), and plasmogamy is initiated by union of the papillae tips. On zygote germination, a single biflagellate gone cell is released from the zygote wall. Although all the anisogamous and oogamous genera of the Volvocaceae produce “sperm packets” during gametogenesis and a single gone cell at zygote germination, some difference can be recognized in the male gametes. The male gametes of Eudorina bear a tubular cytoplasmic protuberance (putative mating papllla) near the base of the flagella, whereas such a structure recognized at the light microscopic level is not evident in Pleodorina and Volvox . Evolution of the sexual reproduction characteristics of volvocacean algae is discussed on the basis of recent cladistic analysis of morphological data as well as of the ribosomal (r) RNA phylogeny and large subunit of the ribulose-1, 5-biphosphate carboxylase/oxygenase(rbcL) gene trees.

  • Pandorina colemaniae sp. nov. (Volvocaceae, Chlorophyta) from Japan
    Phycologia, 1991
    Co-Authors: Hisayoshi Nozaki, Tsuneyoshi Kuroiwa
    Abstract:

    Abstract The morphology, reproduction and taxonomy of Pandorina colemaniae Nozaki sp. nov. (Volvocaceae, Chlorophyta) were studied using clonal cultured materials from Okayama Prefecture, Japan. This species is distinguished from other Pandorina species by its 8- or 16-celled vegetative colonies, in which multipyrenoid cells are arranged compactly and are contiguous in the centre. The cellular and colonial organization observed with light and electron microscopy and the mode of asexual reproduction suggest that P. colemaniae is closely related to the type species, P. morum (O.F. Muller) Bory. A synoptic key to the species of Pandorina is provided.

Armin Hallmann - One of the best experts on this subject based on the ideXlab platform.

  • Stable nuclear transformation of Pandorina morum
    BMC Biotechnology, 2014
    Co-Authors: Kai Lerche, Armin Hallmann
    Abstract:

    Background: Volvocine green algae like Pandorina morum represent one of the most recent inventions of multicellularity diverged from their unicellular relatives. The 8–16 celled P. morum alga and its close multicellular relatives constitute a model lineage for research into cellular differentiation, morphogenesis and epithelial folding, sexual reproduction and evolution of multicellularity. Pandorina is the largest and most complex organism in the volvocine lineage that still exhibits isogamous sexual reproduction. So far, molecular-biological investigations in P. morum were constricted due to the absence of methods for transformation of this species, which is a prerequisite for introduction of reporter genes and (modified) genes of interest. Results: Stable nuclear transformation of P. morum was achieved using chimeric constructs with a selectable marker, a reporter gene, promoters and upstream and downstream flanking sequences from heterologous sources. DNA was introduced into the cells by particle bombardment with plasmid-coated gold particles. The aminoglycoside 3′-phosphotransferase VIII (aphVIII) gene of Streptomyces rimosus under control of an artificial, heterologous promoter was used as the selectable marker. The artificial promoter contained a tandem arrangement of the promoter of both the heat shock protein 70A (hsp70A) and the ribulose-1,5-bisphosphat-carboxylase/-oxygenase S3 (rbcS3) gene of Volvox carteri. Due to the expression of aphVIII, transformants gained up to 333-fold higher resistance to paromomycin in comparison to the parent wild-type strain. The heterologous luciferase (gluc )g ene ofGaussia princeps, which was previously genetically engineered to match the nuclear codon usage of Chlamydomonas reinhardtii, was used as a co-transformed, unselectable reporter gene. The expression of the co-bombarded gluc gene in transformants and the induction of gluc by heat shock were demonstrated through bioluminescence assays. Conclusion: Stable nuclear transformation of P. morum using the particle bombardment technique is now feasible. Functional expression of heterologous genes is achieved using heterologous flanking sequences from Volvox carteri and Chlamydomonas reinhardtii .T heaphVIII gene of the actinobacterium S. rimosus can be used as a selectable marker for transformation experiments in the green alga P. morum .T hegluc gene of the marine copepod G. princeps, expressed under control of heterologous promoter elements, represents a suitable reporter gene for monitoring gene expression or for other applications in P. morum.

  • The pherophorins: common, versatile building blocks in the evolution of extracellular matrix architecture in Volvocales.
    The Plant Journal, 2006
    Co-Authors: Armin Hallmann
    Abstract:

    Green algae of the order Volvocales provide an unrivalled opportunity for exploring the transition from unicellularity to multicellularity. They range from unicells, like Chlamydomonas, through homocytic colonial forms with increasing cooperation of individual cells, like Gonium or Pandorina, to heterocytic multicellular forms with different cell types and a complete division of labour, like Volvox. A fundamental requirement for the evolution of multicellularity is the development of a complex, multifunctional extracellular matrix (ECM). The ECM has many functions, which can change under developmental control or as a result of environmental factors. Here molecular data from 15 novel proteins are presented. These proteins have been identified in Chlamydomonas reinhardtii, Gonium pectorale, Pandorina morum and Volvox carteri, and all belong to a single protein family, the pherophorins. Pherophorin-V1 is shown to be a glycoprotein localized to the 'cellular zone' of the V. carteri ECM. Pherophorin-V1 and -V2 mRNAs are strongly induced not only by the sex inducer, which triggers sexual development at extremely low concentrations, but also by mechanical wounding. Like the extensins of higher plants, which are also developmentally controlled or sometimes inducible by wounding, the pherophorins contain a (hydroxy-)proline-rich (HR) rod-like domain and are abundant within the extracellular compartment. In contrast to most extensins, pherophorins have additional globular A and B domains on both ends of the HR domains. Therefore pherophorins most closely resemble a particular class of higher plant extensin, the solanaceous lectins (e.g. potato lectin), suggesting multivalent carbohydrate-binding functions are present within the A and B domains and are responsible for cross-linking. Our results suggest that pherophorins are used as the building blocks for the extracellular scaffold throughout the Volvocales, with the characteristic mesh sizes in different ECM structures being a result of the highly diverse extensions of the HR domains. Pherophorins have therefore been a versatile element during the evolution of ECM architecture in these green algae.

Guoxiang Liu - One of the best experts on this subject based on the ideXlab platform.

  • Comparison of colonial volvocine algae based on phylotranscriptomic analysis of gene family evolution and natural selection
    European Journal of Phycology, 2019
    Co-Authors: Wei-yue Xing, Huiyin Song, Guoxiang Liu
    Abstract:

    This study is the first to determine the transcriptomes of eight colonial volvocine algae: Pandorina morum, P. colemaniae, Volvulina compacta, Eudorina elegans, E. cylindrica, Yamagishiella unicocc...

  • Evolutionary Analysis of Unicellular Species in Chlamydomonadales Through Chloroplast Genome Comparison With the Colonial Volvocine Algae.
    Frontiers in microbiology, 2019
    Co-Authors: Wei-yue Xing, Huiyin Song, Huan Zhu, Guoxiang Liu
    Abstract:

    This study is the first determination of six chloroplast genomes of colonial volvocine algae, Colemanosphaera charkowiensis, Volvulina compacta, Pandorina colemaniae, Pandorina morum, Colemanosphaera angeleri, and Yamagishiella unicocca. Based on 55 chloroplast protein-coding genes, we compared the nonsynonymous (dN) and synonymous (dS) substitution rates between colonial volvocine algae and the other unicellular Chlamydomonadales species. When refer to the dN, we found 27 genes were significantly different, among them, 19 genes were significant higher in unicellular species (FDR-adjusted P < 0.05). When refer to the dS, we found 10 genes were significantly different, among them, 6 genes were significant higher in unicellular species (FDR-adjusted P < 0.05). Then we identified 14 putative fast-evolving genes and 11 putative positively selected genes of unicellular species, we analyzed the function of positively selected sites of the overlap genes of putative fast-evolving and positively selected genes, and found some sites were close to the important functional region of the proteins. Photosynthesis is the process to transform and store solar energy by chloroplast, it plays a vital role in the survival of algae, this study is the first to use the chloroplast genomes to analysis the evolutionary relationship between colonial and unicellular species in Chlamydomonadales. We found more genes have higher substitution rates in unicellular species and proposed that the fast-evolving and positively selected two genes, psbA and psbC, may help to improve the photosynthetic efficiency of unicellular species in Chlamydomonadales.

Tsuneyoshi Kuroiwa - One of the best experts on this subject based on the ideXlab platform.

Related terms

Pandorina - 15 days free trial to Access Experts & Abstracts