scholarly journals Nuclear genome of a pedinophyte pinpoints genomic innovation and streamlining in the green algae

2021 ◽  
Author(s):  
Sonja I Repetti ◽  
Cintia Iha ◽  
Kavitha Uthanumallian ◽  
Christopher J Jackson ◽  
Yibi Chen ◽  
...  
Keyword(s):  
Green Algae ◽  
Nuclear Genome

Nuclear genome of a pedinophyte pinpoints genomic innovation and streamlining in the green algae

2021 ◽  
Author(s):  
Sonja I. Repetti ◽  
Cintia Iha ◽  
Kavitha Uthanumallian ◽  
Christopher J. Jackson ◽  
Yibi Chen ◽  
...  
Keyword(s):  
Green Algae ◽  
Common Ancestor ◽  
Nuclear Genome ◽  
Genomic Diversity ◽  
Biological Functions ◽  
High Quality ◽  
The Core ◽  
Homologous Genes ◽  
Intermediate Size ◽  
Selection For

The genomic diversity underpinning high ecological and species diversity in the green algae (Chlorophyta) remains little known. Here, we aimed to track genome evolution in the Chlorophyta, focusing on loss and gain of homologous genes, and lineage-specific innovations of the Core Chlorophyta. We generated a high-quality nuclear genome for pedinophyte YPF701, a sister lineage to others in the Core Chlorophyta, and incorporated this genome in a comparative analysis with 25 other genomes from diverse Viridiplantae taxa. The nuclear genome of pedinophyte YPF701 has an intermediate size and gene number between those of most early-diverging prasinophytes and the remainder of the Core Chlorophyta. Our results suggest positive selection for genome streamlining in Pedinophyceae, independent from genome minimisation observed among prasinophyte lineages. Genome expansion was predicted along the branch leading to the UTC clade (classes Ulvophyceae, Trebouxiophyceae and Chlorophyceae) after divergence from their common ancestor with pedinophytes, with genomic novelty implicated in a range of basic biological functions. These results emphasise multiple independent signals of genome minimisation within the Chlorophyta, as well as the genomic novelty arising prior to diversification in the UTC clade, which may underpin the success of this species-rich clade in a diversity of habitats.

scholarly journals Helicosporidia: a genomic snapshot of an early transition to parasitism

2014 ◽  
Vol 83 (4) ◽  
pp. 377-385 ◽  
Author(s):  
Yukun Sun ◽  
Jean-Francois Pombert
Keyword(s):  
Green Algae ◽  
Current Knowledge ◽  
Nuclear Genome ◽  
Molecular Analyses ◽  
Green Algal ◽  
Nuclear Genomes ◽  
Early Transition

Helicosporidia are gut parasites of invertebrates. These achlorophyllous, non-photosynthetic green algae are the first reported to infect insects. Helicosporidia are members of the green algal class Trebouxiophyceae and are further related to the photosynthetic and non-photosynthetic genera <em>Auxenochlorella</em> and <em>Prototheca</em>, respectively, the latter of which can also turn to parasitism under opportunistic conditions. Molecular analyses suggest that Helicosporidia diverged from other photosynthetic trebouxiophytes less than 200 million years ago and that its adaptation to parasitism is therefore recent. In this minireview, we summarize the current knowledge of helicosporidian genomics. Unlike many well-known parasitic lineages, the <em>Helicosporidium</em> sp. organelle and nuclear genomes have lost surprisingly little in terms of coding content aside from photosynthesis-related genes. While the small size of its nuclear genome compared to other sequenced trebouxiophycean representatives suggests that <em>Helicosporidium</em> is going through a streamlining process, this scenario cannot be ascertained at this stage. Genome expansions and contractions have occurred independently multiple times in the green algae, and the small size of the <em>Helicosporidium</em> genome may reflect a lack of expansion from a lean ancestor state rather than a tendency towards reduction.

scholarly journals Characterization of Two Zygnema Strains (Zygnema circumcarinatum SAG 698-1a and SAG 698-1b) and a Rapid Method to Estimate Nuclear Genome Size of Zygnematophycean Green Algae

2021 ◽  
Vol 12 ◽  
Author(s):  
Xuehuan Feng ◽  
Andreas Holzinger ◽  
Charlotte Permann ◽  
Dirk Anderson ◽  
Yanbin Yin
Keyword(s):  
Genome Size ◽  
Green Algae ◽  
Nuclear Genome ◽  
Marker Genes ◽  
Size Estimation ◽  
Simple Method ◽  
Closely Related Species ◽  
Distinct Cell ◽  
Morphological Differences

Zygnematophyceae green algae (ZGA) have been shown to be the closest relatives of land plants. Three nuclear genomes (Spirogloea muscicola, Mesotaenium endlicherianum, and Penium margaritaceum) of ZGA have been recently published, and more genomes are underway. Here we analyzed two Zygnema circumcarinatum strains SAG 698-1a (mating +) and SAG 698-1b (mating −) and found distinct cell sizes and other morphological differences. The molecular identities of the two strains were further investigated by sequencing their 18S rRNA, psaA and rbcL genes. These marker genes of SAG 698-1a were surprisingly much more similar to Z. cylindricum (SAG 698-2) than to SAG 698-1b. Phylogenies of these marker genes also showed that SAG 698-1a and SAG 698-1b were well separated into two different Zygnema clades, where SAG 698-1a was clustered with Z. cylindricum, while SAG 698-1b was clustered with Z. tunetanum. Additionally, physiological parameters like ETRmax values differed between SAG 698-1a and SAG 698-1b after 2 months of cultivation. The de-epoxidation state (DEPS) of the xanthophyll cycle pigments also showed significant differences. Surprisingly, the two strains could not conjugate, and significantly differed in the thickness of the mucilage layer. Additionally, ZGA cell walls are highly enriched with sticky and acidic polysaccharides, and therefore the widely used plant nuclear extraction protocols do not work well in ZGA. Here, we also report a fast and simple method, by mechanical chopping, for efficient nuclear extraction in the two SAG strains. More importantly, the extracted nuclei were further used for nuclear genome size estimation of the two SAG strains by flow cytometry (FC). To confirm the FC result, we have also used other experimental methods for nuclear genome size estimation of the two strains. Interestingly, the two strains were found to have very distinct nuclear genome sizes (313.2 ± 2.0 Mb in SAG 698-1a vs. 63.5 ± 0.5 Mb in SAG 698-1b). Our multiple lines of evidence strongly indicate that SAG 698-1a possibly had been confused with SAG 698-2 prior to 2005, and most likely represents Z. cylindricum or a closely related species.

Freeze-Fracture Replication in the Ultrastructure of Blue-Green Algae

1967 ◽  
Vol 25 ◽  
pp. 74-75
Author(s):  
L. V. Leak
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Green Algae ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Electron Microscopic ◽  
Photosynthetic Membranes ◽  
Blue Green Algae ◽  
Cell Biol ◽  
Cellular Components

Electron microscopic observations of freeze-fracture replicas of Anabaena cells obtained by the procedures described by Bullivant and Ames (J. Cell Biol., 1966) indicate that the frozen cells are fractured in many different planes. This fracturing or cleaving along various planes allows one to gain a three dimensional relation of the cellular components as a result of such a manipulation. When replicas that are obtained by the freeze-fracture method are observed in the electron microscope, cross fractures of the cell wall and membranes that comprise the photosynthetic lamellae are apparent as demonstrated in Figures 1 & 2.A large portion of the Anabaena cell is composed of undulating layers of cytoplasm that are bounded by unit membranes that comprise the photosynthetic membranes. The adjoining layers of cytoplasm are closely apposed to each other to form the photosynthetic lamellae. Occassionally the adjacent layers of cytoplasm are separated by an interspace that may vary in widths of up to several 100 mu to form intralamellar vesicles.

A Scanning Electron Microscopic Study of Pro-Vascular Cellular Morphology in Chaetophora Incressata

1985 ◽  
Vol 43 ◽  
pp. 638-639
Author(s):  
A. E. Hotchkiss ◽  
A. T. Hotchkiss ◽  
R. P. Apkarian
Keyword(s):  
Green Algae ◽  
Vascular Plants ◽  
Vascular System ◽  
Higher Plants ◽  
Wall Structure ◽  
Electron Microscopic ◽  
Physiological Processes ◽  
Scanning Electron Microscopic Study ◽  
Scanning Electron Microscopic ◽  
Scanning Electron

Multicellular green algae may be an ancestral form of the vascular plants. These algae exhibit cell wall structure, chlorophyll pigmentation, and physiological processes similar to those of higher plants. The presence of a vascular system which provides water, minerals, and nutrients to remote tissues in higher plants was believed unnecessary for the algae. Among the green algae, the Chaetophorales are complex highly branched forms that might require some means of nutrient transport. The Chaetophorales do possess apical meristematic groups of cells that have growth orientations suggestive of stem and root positions. Branches of Chaetophora incressata were examined by the scanning electron microscope (SEM) for ultrastructural evidence of pro-vascular transport.

The Influence of Lead and Copper on Some Indices of Vital Activity of Green and Blue-green Algae

2001 ◽  
Vol 37 (2) ◽  
pp. 13
Author(s):  
V. A. Medved'
Keyword(s):  
Green Algae ◽  
Vital Activity ◽  
Blue Green Algae

Peculiarities of Energetic, Nitrogen, and Phosphorus Metabolism in Blue-Green Algae under the Influence of Humic Acids

2008 ◽  
Vol 44 (6) ◽  
pp. 74-82
Author(s):  
O. V. Sinyuk ◽  
V. V. Grubinko ◽  
P. D. Klochenko ◽  
T. A. Vasilchuk
Keyword(s):  
Green Algae ◽  
Humic Acids ◽  
Phosphorus Metabolism ◽  
Nitrogen And Phosphorus ◽  
Blue Green Algae

Peculiarities of Accumulation of Proteins, Carbohydrates and Lipids in the Cells of Green Algae under Different Light Conditions and Photoperiod

2020 ◽  
Vol 56 (3) ◽  
pp. 97-104
Author(s):  
V. O. Medved ◽  
Z. N. Gorbunova ◽  
T. V. Vitovetska
Keyword(s):  
Green Algae ◽  
Light Conditions

Biochemical Composition of Green Algae at Different Stages of Their Growth

2015 ◽  
Vol 51 (4) ◽  
pp. 39-45
Author(s):  
N. I. Kirpenko ◽  
O. M. Usenko ◽  
T. O. Musiy
Keyword(s):  
Green Algae ◽  
Biochemical Composition
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