scholarly journals NO GAMETOPHORES 2 is a novel regulator of the 2D to 3D growth transition in the moss Physcomitrium patens

2020 ◽  
Author(s):  
Laura A. Moody ◽  
Steven Kelly ◽  
Roxaana Clayton ◽  
Zoe Weeks ◽  
David M. Emms ◽  
...  
Keyword(s):  
Physcomitrella Patens ◽  
Lignin Biosynthesis ◽  
Morphological Diversity ◽  
Feedback Mechanism ◽  
3 Dimensional ◽  
History Of ◽  
Acid Pathway ◽  
Life On Earth ◽  
Colonization Of Land ◽  
2D To 3D

SUMMARYThe colonization of land by plants was one of the most transformative events in the history of life on Earth. The transition from water, which coincided with and was likely facilitated by the evolution of 3-dimensional (3D) growth, enabled the generation of morphological diversity on land. In many plants, the transition from 2-dimensional (2D) to 3D growth occurs during embryo development. However, in the early divergent moss Physcomitrium patens (formerly Physcomitrella patens), 3D growth is preceded by an extended filamentous phase that can be maintained indefinitely. Here, we describe the identification of the cytokinin-responsive NO GAMETOPHORES 2 (PpNOG2) gene, which encodes a shikimate o- hydroxycinnamoyltransferase. In mutants lacking PpNOG2 function, transcript levels of CLAVATA and SCARECROW genes are significantly reduced, excessive gametophore initial cells are produced, and buds undergo premature developmental arrest. Our results suggest that PpNOG2 functions in the ascorbic acid pathway leading to cuticle formation, and that NOG2-related genes were co-opted into the lignin biosynthesis pathway after the divergence of bryophytes and vascular plants. We present a revised model of 3D growth in which PpNOG2 comprises part of a feedback mechanism that is required for the modulation of gametophore initial cell frequency. We also propose that the 2D to 3D growth transition in P. patens is underpinned by complex auxin-cytokinin crosstalk that is regulated, at least in part, by changes in flavonoid metabolism.

scholarly journals Transformation of Riccia fluitans, an Amphibious Liverwort Dynamically Responding to Environmental Changes

2020 ◽  
Vol 21 (15) ◽  
pp. 5410
Author(s):  
Felix Althoff ◽  
Sabine Zachgo
Keyword(s):  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Morphological Plasticity ◽  
Terrestrial Ecosystems ◽  
Transformation Protocol ◽  
Major Transition ◽  
Terrestrial Environments ◽  
History Of ◽  
Life On Earth ◽  
Colonization Of Land

The colonization of land by streptophyte algae, ancestors of embryophyte plants, was a fundamental event in the history of life on earth. Bryophytes are early diversifying land plants that mark the transition from freshwater to terrestrial ecosystems. The amphibious liverwort Riccia fluitans can thrive in aquatic and terrestrial environments and thus represents an ideal organism to investigate this major transition. Therefore, we aimed to establish a transformation protocol for R. fluitans to make it amenable for genetic analyses. An Agrobacterium transformation procedure using R. fluitans callus tissue allows to generate stably transformed plants within 10 weeks. Furthermore, for comprehensive studies spanning all life stages, we demonstrate that the switch from vegetative to reproductive development can be induced by both flooding and poor nutrient availability. Interestingly, a single R. fluitans plant can consecutively adapt to different growth environments and forms distinctive and reversible features of the thallus, photosynthetically active tissue that is thus functionally similar to leaves of vascular plants. The morphological plasticity affecting vegetative growth, air pore formation, and rhizoid development realized by one genotype in response to two different environments makes R. fluitans ideal to study the adaptive molecular mechanisms enabling the colonialization of land by aquatic plants.

Conclusion

2017 ◽  
Author(s):  
Erin Lambert
Keyword(s):  
Dutch Reformed ◽  
Christian Life ◽  
The Reformation ◽  
History Of ◽  
Life On Earth

This conclusion offers a brief commentary on the implications of song, resurrection, and belief for the broader history of the Reformation. It relates the various uses of song by Lutherans (hymn pamphlets), Anabaptists (martyr songs), Dutch Reformed exiles (psalms), and Catholics (motets) to these confessions’ ideas of belief as it concerned resurrection and their understandings of how belief was bound up with the Christian life on earth. In place of a story of the transformation of one conception of Christianity to many different conceptions, this book as a whole suggests that the Reformation might be reconceived as a much more elemental debate about the role that belief was to play in a Christian life.

scholarly journals Peculiar Evolutionary History of miR390-Guided TAS3-Like Genes in Land Plants

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Maria S. Krasnikova ◽  
Denis V. Goryunov ◽  
Alexey V. Troitsky ◽  
Andrey G. Solovyev ◽  
Lydmila V. Ozerova ◽  
...  
Keyword(s):  
Genomic Dna ◽  
Physcomitrella Patens ◽  
Land Plant ◽  
Plant Evolution ◽  
Marchantia Polymorpha ◽  
History Of ◽  
Molecular Machinery ◽  
Specific Mrnas ◽  
Land Plant Evolution ◽  
Phylogenetic Profiling

PCR-based approach was used as a phylogenetic profiling tool to probe genomic DNA samples from representatives of evolutionary distant moss taxa, namely, classes Bryopsida, Tetraphidopsida, Polytrichopsida, Andreaeopsida, and Sphagnopsida. We found relatives of allPhyscomitrella patensmiR390 and TAS3-like loci in these plant taxa excluding Sphagnopsida. Importantly, cloning and sequencing ofMarchantia polymorphagenomic DNA showed miR390 and TAS3-like sequences which were also found among genomic reads ofM. polymorphaat NCBI database. Our data suggest that the ancient plant miR390-dependent TAS molecular machinery firstly evolved to target AP2-like mRNAs in Marchantiophyta and only then both ARF- and AP2-specific mRNAs in mosses. The presented analysis shows that moss TAS3 families may undergone losses of tasiAP2 sites during evolution toward ferns and seed plants. These data confirm that miR390-guided genes coding for ARF- and AP2-specific ta-siRNAs have been gradually changed during land plant evolution.

scholarly journals New Evo-SETI results about civilizations and molecular clock

2016 ◽  
Vol 16 (1) ◽  
pp. 40-59 ◽  
Author(s):  
Claudio Maccone
Keyword(s):  
Probability Density ◽  
Molecular Clock ◽  
Modern Human ◽  
Peak Time ◽  
List Type ◽  
Type Number ◽  
Death Time ◽  
Evolution Of Life ◽  
History Of ◽  
Life On Earth

AbstractIn two recent papers (Maccone 2013, 2014) as well as in the book (Maccone 2012), this author described the Evolution of life on Earth over the last 3.5 billion years as a lognormal stochastic process in the increasing number of living Species. In (Maccone 2012, 2013), the process used was ‘Geometric Brownian Motion’ (GBM), largely used in Financial Mathematics (Black-Sholes models). The GBM mean value, also called ‘the trend’, always is an exponential in time and this fact corresponds to the so-called ‘Malthusian growth’ typical of population genetics. In (Maccone 2014), the author made an important generalization of his theory by extending it to lognormal stochastic processes having an arbitrary trend mL(t), rather than just a simple exponential trend as the GBM have.The author named ‘Evo-SETI’ (Evolution and SETI) his theory inasmuch as it may be used not only to describe the full evolution of life on Earth from RNA to modern human societies, but also the possible evolution of life on exoplanets, thus leading to SETI, the current Search for ExtraTerrestrial Intelligence. In the Evo-SETI Theory, the life of a living being (let it be a cell or an animal or a human or a Civilization of humans or even an ET Civilization) is represented by a b-lognormal, i.e. a lognormal probability density function starting at a precise instant b (‘birth’) then increasing up to a peak-time p, then decreasing to a senility-time s (the descending inflexion point) and then continuing as a straight line down to the death-time d (‘finite b-lognormal’).(1)Having so said, the present paper describes the further mathematical advances made by this author in 2014–2015, and is divided in two halves: Part One, devoted to new mathematical results about the History of Civilizations as b-lognormals, and(2)Part Two, about the applications of the Evo-SETI Theory to the Molecular Clock, well known to evolutionary geneticists since 50 years: the idea is that our EvoEntropy grows linearly in time just as the molecular clock. (a)Summarizing the new results contained in this paper: In Part One, we start from the History Formulae already given in (Maccone 2012, 2013) and improve them by showing that it is possible to determine the b-lognormal not only by assigning its birth, senility and death, but rather by assigning birth, peak and death (BPD Theorem: no assigned senility). This is precisely what usually happens in History, when the life of a VIP is summarized by giving birth time, death time, and the date of the peak of activity in between them, from which the senility may then be calculated (approximately only, not exactly). One might even conceive a b-scalene (triangle) probability density just centred on these three points (b, p, d) and we derive the relevant equations. As for the uniform distribution between birth and death only, that is clearly the minimal description of someone's life, we compare it with both the b-lognormal and the b-scalene by comparing the Shannon Entropy of each, which is the measure of how much information each of them conveys. Finally we prove that the Central Limit Theorem (CLT) of Statistics becomes a new ‘E-Pluribus-Unum’ Theorem of the Evo-SETI Theory, giving formulae by which it is possible to find the b-lognormal of the History of a Civilization C if the lives of its Citizens Ci are known, even if only in the form of birth and death for the vast majority of the Citizens.(b)In Part Two, we firstly prove the crucial Peak-Locus Theorem for any given trend mL(t) and not just for the GBM exponential. Then we show that the resulting Evo-Entropy grows exactly linearly in time if the trend is the exponential GMB trend.(c)In addition, three Appendixes (online) with all the relevant mathematical proofs are attached to this paper. They are written in the Maxima language, and Maxima is a symbolic manipulator that may be downloaded for free from the web.In conclusion, this paper further increases the huge mathematical spectrum of applications of the Evo-SETI Theory to prepare Humans for the first Contact with an Extra-Terrestrial Civilization.

scholarly journals From 2D to 3D: an algorithm to derive normal values for 3-dimensional computerized assessment

2011 ◽  
Vol 81 (1) ◽  
pp. 3-10 ◽  
Author(s):  
Bruno Frazão Gribel ◽  
Marcos Nadler Gribel ◽  
Flavio Ricardo Manzi ◽  
Sharon L. Brooks ◽  
James A. McNamara
Keyword(s):  
Normal Values ◽  
Computerized Assessment ◽  
3 Dimensional ◽  
2D To 3D

scholarly journals Dormancy-Associated MADS-Box (DAM) and the Abscisic Acid Pathway Regulate Pear Endodormancy Through a Feedback Mechanism

2017 ◽  
Vol 58 (8) ◽  
pp. 1378-1390 ◽  
Author(s):  
Pham Anh Tuan ◽  
Songling Bai ◽  
Takanori Saito ◽  
Akiko Ito ◽  
Takaya Moriguchi
Keyword(s):  
Abscisic Acid ◽  
Feedback Mechanism ◽  
Mads Box ◽  
Acid Pathway

scholarly journals Evolution of Philodendron (Araceae) species along Neotropical biomes

2016 ◽  
Author(s):  
Leticia Loss-Oliveira ◽  
Cassia CMS Sakuragui ◽  
Maria de Lourdes Soares ◽  
Carlos G Schrago
Keyword(s):  
Morphological Diversity ◽  
Neotropical Region ◽  
Last Common Ancestor ◽  
Amazon Forest ◽  
Ancestral Reconstruction ◽  
Biogeographic History ◽  
Early Diversification ◽  
Sister Clade ◽  
History Of ◽  
Wide Geographic Distribution

Philodendron is the second most diverse genus of the Araceae, a tropical monocot family with significant morphological diversity along its wide geographic distribution in the Neotropics. Although evolutionary studies of Philodendron were conducted in recent years, the phylogenetic relationship among its species remains unclear. Additionally, analyses conducted to date suggested the inclusion of all American representatives of a closely related genus, Homalomena, within the Philodendron clade. A thorough evaluation of the phylogeny and timescale of these lineages is thus necessary to elucidate the tempo and mode of evolution of this large Neotropical genus and to unveil the biogeographic history of Philodendron evolution along the Amazonian and Atlantic Rain Forests, as well as open dry forests of South America. To this end, we have estimated the molecular phylogeny for 68 Philodendron species, which consists of the largest sampling assembled to date aiming the study of the evolutionary affinities. We have also performed ancestral reconstruction of species distribution along biomes. Finally, we contrasted these results with the inferred timescale of Philodendron and Homalomena lineage diversification. Our estimates indicate that American Homalomena is the sister clade to Philodendron. The early diversification of Philodendron took place in the Amazon Forest from Early to Middle Miocene, followed by colonization of the Atlantic Forest and the savanna-like landscapes, respectively. Based on the age of the last common ancestor of Philodendron, the species of this genus diversified by rapid radiations, leading to its wide extant distribution in the Neotropical region.

scholarly journals Origin of DNA Repair in the RNA World

2020 ◽  
Author(s):  
Harris Bernstein ◽  
Carol Bernstein
Keyword(s):  
Rna World ◽  
Template Strand ◽  
Repair Processes ◽  
Survival Selection ◽  
Genome Damage ◽  
Spontaneous Hydrolysis ◽  
History Of ◽  
Basic Features ◽  
Life On Earth ◽  
Genome Repair

The early history of life on Earth likely included a stage in which life existed as self-replicating protocells with single-stranded RNA (ssRNA) genomes. In this RNA world, genome damage from a variety of sources (spontaneous hydrolysis, UV, etc.) would have been a problem for survival. Selection pressure for dealing with genome damage would have led to adaptive strategies for mitigating the damage. In today’s world, RNA viruses with ssRNA genomes are common, and these viruses similarly need to cope with genome damage. Thus ssRNA viruses can serve as models for understanding the early evolution of genome repair. As the ssRNA protocells in the early RNA world evolved, the RNA genome likely gave rise, through a series of evolutionary stages, to the double-stranded DNA (dsDNA) genome. In ssRNA to dsDNA evolution, genome repair processes also likely evolved to accommodate this transition. Some of the basic features of ssRNA genome repair appear to have been retained in descendants with dsDNA genomes. In particular, a type of strand-switching recombination occurs when ssRNA replication is blocked by a damage in the template strand. Elements of this process appear to have a central role in recombinational repair processes during meiosis and mitosis of descendant dsDNA organisms.

The “evolution” of Anomalocaris and its classification in the arthropod class Dinocarida (nov.) and order Radiodonta (nov.)

1996 ◽  
Vol 70 (2) ◽  
pp. 280-293 ◽  
Author(s):  
Desmond Collins
Keyword(s):  
British Columbia ◽  
Sea Cucumber ◽  
Great Difficulty ◽  
Burgess Shale ◽  
Middle Cambrian ◽  
The Past ◽  
History Of ◽  
The Many ◽  
Life On Earth ◽  
Mistaken Identification

The remarkable “evolution” of the reconstructions of Anomalocaris, the extraordinary predator from the 515 million year old Middle Cambrian Burgess Shale of British Columbia, reflects the dramatic changes in our interpretation of early animal life on Earth over the past 100 years. Beginning in 1892 with a claw identified as the abdomen and tail of a phyllocarid crustacean, parts of Anomalocaris have been described variously as a jellyfish, a sea-cucumber, a polychaete worm, a composite of a jellyfish and sponge, or have been attached to other arthropods as appendages. Charles D. Walcott collected complete specimens of Anomalocaris nathorsti between 1911 and 1917, and a Geological Survey of Canada party collected an almost complete specimen of Anomalocaris canadensis in 1966 or 1967, but neither species was adequately described until 1985. At that time they were interpreted by Whittington and Briggs to be representatives of “a hitherto unknown phylum.”Here, using recently collected specimens, the two species are newly reconstructed and described in the genera Anomalocaris and Laggania, and interpreted to be members of an extinct arthropod class, Dinocarida, and order Radiodonta, new to science. The long history of inaccurate reconstruction and mistaken identification of Anomalocaris and Laggania exemplifies our great difficulty in visualizing and classifying, from fossil remains, the many Cambrian animals with no apparent living descendants.

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