RSL Class I Genes Controlled the Development of Epidermal Structures in the Common Ancestor of Land Plants

There are two general types of rooting systems in extant land plants: gametophyte rhizoids and sporophyte root axes. These structures carry out the rooting function in the free-living stage of almost all land plant gametophytes and sporophytes, respectively. Extant vascular plants develop a dominant, free-living sporophyte on which roots form, with the exception of a small number of taxa that have secondarily lost roots. However, fossil evidence indicates that early vascular plants did not develop sporophyte roots. We propose that the common ancestor of vascular plants developed a unique rooting system—rhizoidal sporophyte axes. Here we present a synthesis and reinterpretation of the rootless sporophytes of Horneophyton lignieri , Aglaophyton majus , Rhynia gwynne-vaughanii and Nothia aphylla preserved in the Rhynie chert. We show that the sporophyte rooting structures of all four plants comprised regions of plagiotropic (horizontal) axes that developed unicellular rhizoids on their underside. These regions of axes with rhizoids developed bilateral symmetry making them distinct from the other regions which were radially symmetrical. We hypothesize that rhizoidal sporophyte axes constituted the rooting structures in the common ancestor of vascular plants because the phylogenetic positions of these plants span the origin of the vascular lineage. This article is part of a discussion meeting issue ‘The Rhynie cherts: our earliest terrestrial ecosystem revisited’.

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The Possible Common Origin of tRNA and 5S rRNA

Zeitschrift für Naturforschung C ◽

10.1515/znc-1983-5-633 ◽

1983 ◽

Vol 38 (5-6) ◽

pp. 501-504 ◽

Cited By ~ 2

Author(s):

Mária Ujhelyi

Keyword(s):

Common Ancestor ◽

Common Origin ◽

5S Rrna ◽

Mitochondrial Trna ◽

Trna Molecule ◽

The Common

Seryl tRNA (anticodon GCU) from mammalian mitochondria shows in comparison to other mitochondrial tRNAs additional special features differing from the generalized tRNA model. When arranged in the traditional cloverleaf form, eight bases fall within the TΨC loop, and the entire dihydrouridine loop is lacking. This seryl tRNA molecule is therefore shorter than other tRNAs. It was originally thought to represent a mitochondrial analogon of 5 S rRNA and its precise classification is still disputed. The present studies suggest that this mitochondrial tRNA represents a fossil molecule which is related to the common ancestor of the present tRNA and 5 S rRNA molecules.

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Role of the Digestive Gland in Ink Production in Four Species of Sea Hares: An Ultrastructural Comparison

Journal of Marine Biology ◽

10.1155/2013/209496 ◽

2013 ◽

Vol 2013 ◽

pp. 1-5 ◽

Cited By ~ 3

Author(s):

Jeffrey S. Prince ◽

Paul Micah Johnson

Keyword(s):

Digestive Gland ◽

Common Ancestor ◽

Aplysia Californica ◽

Digestive Cell ◽

Digestive Cells ◽

Sea Hare ◽

Red Algal ◽

The Common ◽

Algal Chloroplast

The ultrastructure of the digestive gland of several sea hare species that produce different colored ink (Aplysia californicaproduces purple ink,A. julianawhite ink,A. parvulaboth white and purple ink, whileDolabrifera dolabriferaproduces no ink at all) was compared to determine the digestive gland’s role in the diet-derived ink production process. Rhodoplast digestive cells and their digestive vacuoles, the site of digestion of red algal chloroplast (i.e., rhodoplast) inA. californica, were present and had a similar ultrastructure in all four species. Rhodoplast digestive cell vacuoles either contained a whole rhodoplast or fragments of one or were empty. These results suggest that the inability to produce colored ink in some sea hare species is not due to either an absence of appropriate digestive machinery, that is, rhodoplast digestive cells, or an apparent failure of rhodoplast digestive cells to function. These results also propose that the digestive gland structure described herein occurred early in sea hare evolution, at least in the common ancestor to the generaAplysiaandDolabrifera. Our data, however, do not support the hypothesis that the loss of purple inking is a synapomorphy of the white-ink-producing subgenusAplysia.

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Sexual reproduction and genetic exchange in parasitic protists

Parasitology ◽

10.1017/s0031182014001693 ◽

2014 ◽

Vol 142 (S1) ◽

pp. S120-S127 ◽

Cited By ~ 29

Author(s):

GARETH D. WEEDALL ◽

NEIL HALL

Keyword(s):

Life Cycle ◽

Genome Sequencing ◽

Common Ancestor ◽

Life Cycles ◽

Animal Disease ◽

Eukaryotic Evolution ◽

Sequencing Technology ◽

Parasite Reproduction ◽

The Common ◽

Higher Eukaryotes

SUMMARYA key part of the life cycle of an organism is reproduction. For a number of important protist parasites that cause human and animal disease, their sexuality has been a topic of debate for many years. Traditionally, protists were considered to be primitive relatives of the ‘higher’ eukaryotes, which may have diverged prior to the evolution of sex and to reproduce by binary fission. More recent views of eukaryotic evolution suggest that sex, and meiosis, evolved early, possibly in the common ancestor of all eukaryotes. However, detecting sex in these parasites is not straightforward. Recent advances, particularly in genome sequencing technology, have allowed new insights into parasite reproduction. Here, we review the evidence on reproduction in parasitic protists. We discuss protist reproduction in the light of parasitic life cycles and routes of transmission among hosts.

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Whole-genome analysis-based phylogeographic investigation of Streptococcus pneumoniae serotype 19A sequence type 320 isolates in Japan.

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.01395-21 ◽

2021 ◽

Author(s):

Satoshi Nakano ◽

Takao Fujisawa ◽

Bin Chang ◽

Yutaka Ito ◽

Hideki Akeda ◽

...

Keyword(s):

Common Ancestor ◽

Sampling Bias ◽

Health Concern ◽

Recent Common Ancestor ◽

Whole Genome ◽

Whole Genome Analysis ◽

Identification Rate ◽

Most Recent Common Ancestor ◽

The Common ◽

The U.S

After the introduction of the seven-valent pneumococcal conjugate vaccine, the global spread of multidrug resistant serotype 19A-ST320 strains became a public health concern. In Japan, the main genotype of serotype 19A was ST3111, and the identification rate of ST320 was low. Although the isolates were sporadically detected in both adults and children, their origin remains unknown. Thus, by combining pneumococcal isolates collected in three nationwide pneumococcal surveillance studies conducted in Japan between 2008 and 2020, we analyzed 56 serotype 19A-ST320 isolates along with 931 global isolates, using whole-genome sequencing to uncover the transmission route of the globally distributed clone in Japan. The clone was frequently detected in Okinawa Prefecture, where the U.S. returned to Japan in 1972. Phylogenetic analysis demonstrated that the isolates from Japan were genetically related to those from the U.S.; therefore, the common ancestor may have originated in the U.S. In addition, Bayesian analysis suggested that the time to the most recent common ancestor of the isolates form Japan and the U.S. was approximately the 1990s to 2000, suggesting the possibility that the common ancestor could have already spread in the U.S. before the Taiwan 19F-14 isolate was first identified in a Taiwanese hospital in 1997. The phylogeographical analysis supported the transmission of the clone from the U.S. to Japan, but the analysis could be influenced by sampling bias. These results suggested the possibility that the serotype 19A-ST320 clone had already spread in the U.S. before being imported into Japan.

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The Common Ancestor of Man and Apes

Science ◽

10.1126/science.59.1530.xii-s ◽

1924 ◽

Vol 59 (1530) ◽

Keyword(s):

Common Ancestor ◽

The Common

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From the Common Ancestor of all Living Organisms to Protoeukaryotic Cell

Thermophiles ◽

10.1201/9781482273045-33 ◽

1998 ◽

pp. 307-316

Keyword(s):

Common Ancestor ◽

The Common ◽

Living Organisms

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Comparing the folding landscapes of evolutionarily divergent procaspase-3

10.1101/2022.01.12.476064 ◽

2022 ◽

Author(s):

Liqi Yao ◽

Clay Clark

Keyword(s):

Conformational Change ◽

Common Ancestor ◽

Folding Pathway ◽

Free Energies ◽

Folding Intermediates ◽

Effector Caspases ◽

The Common ◽

Ph Dependent ◽

Species Specific ◽

Dimeric Intermediate

All caspases evolved from a common ancestor and subsequently developed into two general classes, inflammatory or apoptotic caspases. The caspase-hemoglobinase fold has been conserved throughout nearly one billion years of evolution and is utilized for both the monomeric and dimeric subfamilies of apoptotic caspases, called initiator and effector caspases, respectively. We compared the folding and assembly of procaspase-3b from zebrafish to that of human effector procaspases in order to examine the conservation of the folding landscape. Urea-induced equilibrium folding/unfolding of procaspase-3b showed a minimum three-state folding pathway, where the native dimer isomerizes to a partially folded dimeric intermediate, which then unfolds. A partially folded monomeric intermediate observed in the folding landscape of human procaspase-3 is not well-populated in zebrafish procaspase-3b. By comparing effector caspases from different species, we show that the effector procaspase dimer undergoes a pH-dependent conformational change, and that the conformational species in the folding landscape exhibit similar free energies. Together, the data show that the landscape for the caspase-hemoglobinase fold is conserved, yet it provides flexibility for species-specific stabilization or destabilization of folding intermediates resulting in changes in stability. The common pH-dependent conformational change in the native dimer, which yields an enzymatically inactive species, may provide an additional, albeit reversible, mechanism for controlling caspase activity in the cell.

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Loss of plastid developmental genes coincides with a reversion to monoplastidy in hornworts

10.1101/2022.01.11.475830 ◽

2022 ◽

Author(s):

Alexander Istvan MacLeod ◽

Parth K Raval ◽

Simon Stockhorst ◽

Michael Knopp ◽

Eftychios Frangedakis ◽

...

Keyword(s):

Common Ancestor ◽

Nuclear Division ◽

Developmental Pathways ◽

Ancestral State ◽

Plastid Division ◽

Plastid Development ◽

State Reconstruction ◽

Transcriptomic Data ◽

The Common ◽

Almost All

The first plastid evolved from an endosymbiotic cyanobacterium in the common ancestor of the Archaeplastida. The transformative steps from cyanobacterium to organelle included the transfer of control over developmental processes; a necessity for the host to orchestrate, for example, the fission of the organelle. The plastids of almost all embryophytes divide independent from nuclear division, leading to cells housing multiple plastids. Hornworts, however, are monoplastidic (or near-monoplastidic) and their photosynthetic organelles are a curious exception among embryophytes for reasons such as the occasional presence of pyrenoids. Here we screened genomic and transcriptomic data of eleven hornworts for components of plastid developmental pathways. We find intriguing differences among hornworts and specifically highlight that pathway components involved in regulating plastid development and biogenesis were differentially lost in this group of bryophytes. In combination with ancestral state reconstruction, our data suggest that hornworts have reverted back to a monoplastidic phenotype due to the combined loss of two plastid division-associated genes: ARC3 and FtsZ2.

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