scholarly journals Chimeric origins of ochrophytes and haptophytes revealed through an ancient plastid proteome

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Richard G Dorrell ◽  
Gillian Gile ◽  
Giselle McCallum ◽  
Raphaël Méheust ◽  
Eric P Bapteste ◽  
...  

Plastids are supported by a wide range of proteins encoded within the nucleus and imported from the cytoplasm. These plastid-targeted proteins may originate from the endosymbiont, the host, or other sources entirely. Here, we identify and characterise 770 plastid-targeted proteins that are conserved across the ochrophytes, a major group of algae including diatoms, pelagophytes and kelps, that possess plastids derived from red algae. We show that the ancestral ochrophyte plastid proteome was an evolutionary chimera, with 25% of its phylogenetically tractable nucleus-encoded proteins deriving from green algae. We additionally show that functional mixing of host and plastid proteomes, such as through dual-targeting, is an ancestral feature of plastid evolution. Finally, we detect a clear phylogenetic signal from one ochrophyte subgroup, the lineage containing pelagophytes and dictyochophytes, in plastid-targeted proteins from another major algal lineage, the haptophytes. This may represent a possible serial endosymbiosis event deep in eukaryotic evolutionary history.

2010 ◽  
Vol 365 (1541) ◽  
pp. 729-748 ◽  
Author(s):  
Patrick J. Keeling

Plastids and mitochondria each arose from a single endosymbiotic event and share many similarities in how they were reduced and integrated with their host. However, the subsequent evolution of the two organelles could hardly be more different: mitochondria are a stable fixture of eukaryotic cells that are neither lost nor shuffled between lineages, whereas plastid evolution has been a complex mix of movement, loss and replacement. Molecular data from the past decade have substantially untangled this complex history, and we now know that plastids are derived from a single endosymbiotic event in the ancestor of glaucophytes, red algae and green algae (including plants). The plastids of both red algae and green algae were subsequently transferred to other lineages by secondary endosymbiosis. Green algal plastids were taken up by euglenids and chlorarachniophytes, as well as one small group of dinoflagellates. Red algae appear to have been taken up only once, giving rise to a diverse group called chromalveolates. Additional layers of complexity come from plastid loss, which has happened at least once and probably many times, and replacement. Plastid loss is difficult to prove, and cryptic, non-photosynthetic plastids are being found in many non-photosynthetic lineages. In other cases, photosynthetic lineages are now understood to have evolved from ancestors with a plastid of different origin, so an ancestral plastid has been replaced with a new one. Such replacement has taken place in several dinoflagellates (by tertiary endosymbiosis with other chromalveolates or serial secondary endosymbiosis with a green alga), and apparently also in two rhizarian lineages: chlorarachniophytes and Paulinella (which appear to have evolved from chromalveolate ancestors). The many twists and turns of plastid evolution each represent major evolutionary transitions, and each offers a glimpse into how genomes evolve and how cells integrate through gene transfers and protein trafficking.


2019 ◽  
Author(s):  
Marko J. Spasojevic ◽  
Sören Weber1

Stable carbon (C) and nitrogen (N) isotopes in plants are important indicators of plant water use efficiency and N acquisition strategies. While often regarded as being under environmental control, there is growing evidence that evolutionary history may also shape variation in stable isotope ratios (δ13C and δ15N) among plant species. Here we examined patterns of foliar δ13C and δ15N in alpine tundra for 59 species in 20 plant families. To assess the importance of environmental controls and evolutionary history, we examined if average δ13C and δ15N predictably differed among habitat types, if individual species exhibited intraspecific trait variation (ITV) in δ13C and δ15N, and if there were a significant phylogenetic signal in δ13C and δ15N. We found that variation among habitat types in both δ13C and δ15N mirrored well-known patterns of water and nitrogen limitation. Conversely, we also found that 40% of species exhibited no ITV in δ13C and 35% of species exhibited no ITV in δ15N, suggesting that some species are under stronger evolutionary control. However, we only found a modest signal of phylogenetic conservatism in δ13C and no phylogenetic signal in δ15N suggesting that shared ancestry is a weaker driver of tundra wide variation in stable isotopes. Together, our results suggest that both evolutionary history and local environmental conditions play a role in determining variation in δ13C and δ15N and that considering both factors can help with interpreting isotope patterns in nature and with predicting which species may be able to respond to rapidly changing environmental conditions.


2017 ◽  
Vol 24 (2) ◽  
pp. 118-125 ◽  
Author(s):  
Rashmi Chandra ◽  
Roberto Parra ◽  
Hafiz M. N. Iqbal

1958 ◽  
Vol 42 (2) ◽  
pp. 243-250 ◽  
Author(s):  
G. C. McLeod

Action spectra for delayed light production by several algae were determined from 250 to 750 mµ incident light. In the visible portion of the spectrum the action spectra resemble those reported by previous workers for photosynthesis and light emission. Blue-green algae had a maximum at 620 mµ, red algae at 550 mµ, whereas green and brown algae have action spectra corresponding to chlorophyll and carotenoid absorption. In the ultraviolet portion of the spectrum delayed light is emitted by algae down to 250 mµ incident light. The action spectra of the different algae are not alike in the ultraviolet portion of the spectrum. This indicates that pigments other than chlorophyll must be sensitizing or shielding the algae in the ultraviolet region.


2020 ◽  
Vol 1 (1) ◽  
pp. 24-31
Author(s):  
Elvi Kustiyah ◽  
Bungaran Saingin ◽  
Hernowo Widodo ◽  
Viriya Piti

 Indonesia has millions island and big part of Indonesia is sea that is rich in marine biological resources and has the potential to be developed and optimized. One of the abundant marine resources in Indonesia is algae. Algae are plant-like protists. Algae have several important compounds, including protein, carbohydrates, fats, minerals and other useful elements. Proteins contained in algae have the potential to be used as antioxidants. In this study, the levels of protein in red and green algae were tested by using the lowry method and testing the antioxidant activity of red and green algae extracts using the Diphenylpicrylhydrazyl (DPPH) method. Algae extraction was done by maceration, which is soaking the sample in low temperature with phosphate buffer saline (PBS) pH 7. From the extraction results it can be concluded that the red algae (Rhodophyta) has the highest protein content of 5.115 ± 0.126% and the lowest protein content in green algae (Chloropytha) as big as 1.686 ± 0.430%. And from the results of the antioxidant activity test showed that all positive algae showed antioxidant activity but the green algae (Chlorophyta) had the highest antioxidant activity of 71.5946 ± 0.01612% with IC50 value 1.6114.


Science ◽  
2021 ◽  
Vol 373 (6556) ◽  
pp. 792-796 ◽  
Author(s):  
Paul K. Strother ◽  
Clinton Foster

Molecular time trees indicating that embryophytes originated around 500 million years ago (Ma) during the Cambrian are at odds with the record of fossil plants, which first appear in the mid-Silurian almost 80 million years later. This time gap has been attributed to a missing fossil plant record, but that attribution belies the case for fossil spores. Here, we describe a Tremadocian (Early Ordovician, about 480 Ma) assemblage with elements of both Cambrian and younger embryophyte spores that provides a new level of evolutionary continuity between embryophytes and their algal ancestors. This finding suggests that the molecular phylogenetic signal retains a latent evolutionary history of the acquisition of the embryophytic developmental genome, a history that perhaps began during Ediacaran-Cambrian time but was not completed until the mid-Silurian (about 430 Ma).


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Max E. Schön ◽  
Vasily V. Zlatogursky ◽  
Rohan P. Singh ◽  
Camille Poirier ◽  
Susanne Wilken ◽  
...  

AbstractThe endosymbiotic origin of plastids from cyanobacteria gave eukaryotes photosynthetic capabilities and launched the diversification of countless forms of algae. These primary plastids are found in members of the eukaryotic supergroup Archaeplastida. All known archaeplastids still retain some form of primary plastids, which are widely assumed to have a single origin. Here, we use single-cell genomics from natural samples combined with phylogenomics to infer the evolutionary origin of the phylum Picozoa, a globally distributed but seemingly rare group of marine microbial heterotrophic eukaryotes. Strikingly, the analysis of 43 single-cell genomes shows that Picozoa belong to Archaeplastida, specifically related to red algae and the phagotrophic rhodelphids. These picozoan genomes support the hypothesis that Picozoa lack a plastid, and further reveal no evidence of an early cryptic endosymbiosis with cyanobacteria. These findings change our understanding of plastid evolution as they either represent the first complete plastid loss in a free-living taxon, or indicate that red algae and rhodelphids obtained their plastids independently of other archaeplastids.


2021 ◽  
Author(s):  
Caitlin Cherryh ◽  
Bui Quang Minh ◽  
Rob Lanfear

AbstractMost phylogenetic analyses assume that the evolutionary history of an alignment (either that of a single locus, or of multiple concatenated loci) can be described by a single bifurcating tree, the so-called the treelikeness assumption. Treelikeness can be violated by biological events such as recombination, introgression, or incomplete lineage sorting, and by systematic errors in phylogenetic analyses. The incorrect assumption of treelikeness may then mislead phylogenetic inferences. To quantify and test for treelikeness in alignments, we develop a test statistic which we call the tree proportion. This statistic quantifies the proportion of the edge weights in a phylogenetic network that are represented in a bifurcating phylogenetic tree of the same alignment. We extend this statistic to a statistical test of treelikeness using a parametric bootstrap. We use extensive simulations to compare tree proportion to a range of related approaches. We show that tree proportion successfully identifies non-treelikeness in a wide range of simulation scenarios, and discuss its strengths and weaknesses compared to other approaches. The power of the tree-proportion test to reject non-treelike alignments can be lower than some other approaches, but these approaches tend to be limited in their scope and/or the ease with which they can be interpreted. Our recommendation is to test treelikeness of sequence alignments with both tree proportion and mosaic methods such as 3Seq. The scripts necessary to replicate this study are available at https://github.com/caitlinch/treelikeness


2017 ◽  
Author(s):  
Ross Mounce

In this thesis I attempt to gather together a wide range of cladistic analyses of fossil and extant taxa representing a diverse array of phylogenetic groups. I use this data to quantitatively compare the effect of fossil taxa relative to extant taxa in terms of support for relationships, number of most parsimonious trees (MPTs) and leaf stability. In line with previous studies I find that the effects of fossil taxa are seldom different to extant taxa – although I highlight some interesting exceptions. I also use this data to compare the phylogenetic signal within vertebrate morphological data sets, by choosing to compare cranial data to postcranial data. Comparisons between molecular data and morphological data have been previously well explored, as have signals between different molecular loci. But comparative signal within morphological data sets is much less commonly characterized and certainly not across a wide array of clades. With this analysis I show that there are many studies in which the evidence provided by cranial data appears to be be significantly incongruent with the postcranial data – more than one would expect to see just by the effect of chance and noise alone. I devise and implement a modification to a rarely used measure of homoplasy that will hopefully encourage its wider usage. Previously it had some undesirable bias associated with the distribution of missing data in a dataset, but my modification controls for this. I also take an in-depth and extensive review of the ILD test, noting it is often misused or reported poorly, even in recent studies. Finally, in attempting to collect data and metadata on a large scale, I uncovered inefficiencies in the research publication system that obstruct re-use of data and scientific progress. I highlight the importance of replication and reproducibility – even simple reanalysis of high profile papers can turn up some very different results. Data is highly valuable and thus it must be retained and made available for further re-use to maximize the overall return on research investment.


2020 ◽  
Vol 8 (3) ◽  
pp. 7
Author(s):  
Silsia Dorkas Winowoda ◽  
Marina Flora Oktavine Singkoh ◽  
Ratna Siahaan

This study aims to analyze the richness and potential of macroalgae bioactive compounds on the Atep Oki Coast, District of Minahasa, North Sulawesi Province. This research was conducted in October 2019 until January 2020. Sampling used the roaming method in a predetermined location that is Atep Oki tidal/ intertidal coast. Sampling locations are spread over six coordinate points. Macroalgae found on the Atep Oki Coast assessed ten species belonging to three phyla, namely Chlorophyta (green algae), Ochrophyta (brown algae) and Rhodophyta (red algae). Chlorophyta members mean six species. Ochrophyta has members of three species and members of Rhodophyta only one species. The types of macroalgae found on the Atep Oki Coast provide bioactive compounds. Keywords : Macroalgae, Bioactive Compounds, Atep Oki Minahasa CoastAbstrak Penelitian ini bertujuan untuk menganalisis kekayaan jenis dan potensi senyawa bioaktif makroalga di Pesisir Atep Oki, Kabupaten Minahasa, Provinsi Sulawesi Utara. Penelitian ini telah dilaksanakan pada bulan Oktober 2019 sampai Januari 2020. Pengambilan sampel menggunakan metode jelajah di lokasi yang telah ditentukan yaitu pesisir pasang surut/intertidal Atep Oki. Lokasi pengambilan sampel tersebar di enam titik-titik koordinat. Makroalga yang ditemukan di Pesisir Atep Oki berjumlah sepuluh species yang tergolong ke dalam tiga filum yaitu Chlorophyta (alga hijau), Ochrophyta (alga cokelat) dan Rhodophyta (alga merah). Anggota Chlorophyta berjumlah enam species. Ochrophyta memiliki anggota tiga species dan anggota Rhodophyta hanya satu species. Jenis-jenis makroalga yang ditemukan di Pesisir Atep Oki berpotensi menghasilkan senyawa bioaktif. Kata kunci : Makroalga, Senyawa Bioaktif, Pesisir Atep Oki Minahasa


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