scholarly journals Bacterial Origin and Reductive Evolution of the CPR Group

2020 ◽  
Vol 12 (3) ◽  
pp. 103-121 ◽  
Author(s):  
Rijja Hussain Bokhari ◽  
Nooreen Amirjan ◽  
Hyeonsoo Jeong ◽  
Kyung Mo Kim ◽  
Gustavo Caetano-Anollés ◽  
...  

Abstract The candidate phyla radiation (CPR) is a proposed subdivision within the bacterial domain comprising several candidate phyla. CPR organisms are united by small genome and physical sizes, lack several metabolic enzymes, and populate deep branches within the bacterial subtree of life. These features raise intriguing questions regarding their origin and mode of evolution. In this study, we performed a comparative and phylogenomic analysis to investigate CPR origin and evolution. Unlike previous gene/protein sequence-based reports of CPR evolution, we used protein domain superfamilies classified by protein structure databases to resolve the evolutionary relationships of CPR with non-CPR bacteria, Archaea, Eukarya, and viruses. Across all supergroups, CPR shared maximum superfamilies with non-CPR bacteria and were placed as deep branching bacteria in most phylogenomic trees. CPR contributed 1.22% of new superfamilies to bacteria including the ribosomal protein L19e and encoded four core superfamilies that are likely involved in cell-to-cell interaction and establishing episymbiotic lifestyles. Although CPR and non-CPR bacterial proteomes gained common superfamilies over the course of evolution, CPR and Archaea had more common losses. These losses mostly involved metabolic superfamilies. In fact, phylogenies built from only metabolic protein superfamilies separated CPR and non-CPR bacteria. These findings indicate that CPR are bacterial organisms that have probably evolved in an Archaea-like manner via the early loss of metabolic functions. We also discovered that phylogenies built from metabolic and informational superfamilies gave contrasting views of the groupings among Archaea, Bacteria, and Eukarya, which add to the current debate on the evolutionary relationships among superkingdoms.

2015 ◽  
Vol 282 (1821) ◽  
pp. 20152210 ◽  
Author(s):  
Martin D. Brazeau ◽  
Valerie de Winter

Solving the evolutionary relationships of the acanthodians is one of the key problems in reconstructing ancestral anatomical conditions for the jawed vertebrates (gnathostomes). Current debate concerns whether acanthodians are an assemblage of stem chondrichthyans, or a more generalized grade encompassing some early stem osteichthyans. The skull anatomy of Acanthodes bronni has been pivotal in these debates, owing to tension between chondrichthyan- and osteichthyan-like models of reconstruction. We use computed tomography scanning and traditional palaeontological techniques to resolve the long-standing debate about the anatomy of the jaw suspension. We establish the correct length of the hyomandibula and show that it attaches to a process on the ventrolateral angle of the braincase below the jugular vein groove. This condition corresponds precisely to that in chondrichthyans. This character represents an unambiguously optimized synapomorphy with chondrichthyans given current gnathostome phylogenies, corroborating the growing consensus of the chondrichthyan affinity of acanthodians.


Microbiome ◽  
2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Wei Lin ◽  
Wensi Zhang ◽  
Greig A. Paterson ◽  
Qiyun Zhu ◽  
Xiang Zhao ◽  
...  

Abstract Background The discovery of membrane-enclosed, metabolically functional organelles in Bacteria has transformed our understanding of the subcellular complexity of prokaryotic cells. Biomineralization of magnetic nanoparticles within magnetosomes by magnetotactic bacteria (MTB) is a fascinating example of prokaryotic organelles. Magnetosomes, as nano-sized magnetic sensors in MTB, facilitate cell navigation along the local geomagnetic field, a behaviour referred to as magnetotaxis or microbial magnetoreception. Recent discovery of novel MTB outside the traditionally recognized taxonomic lineages suggests that MTB diversity across the domain Bacteria are considerably underestimated, which limits understanding of the taxonomic distribution and evolutionary origin of magnetosome organelle biogenesis. Results Here, we perform the most comprehensive metagenomic analysis available of MTB communities and reconstruct metagenome-assembled MTB genomes from diverse ecosystems. Discovery of MTB in acidic peatland soils suggests widespread MTB occurrence in waterlogged soils in addition to subaqueous sediments and water bodies. A total of 168 MTB draft genomes have been reconstructed, which represent nearly a 3-fold increase over the number currently available and more than double the known MTB species at the genome level. Phylogenomic analysis reveals that these genomes belong to 13 Bacterial phyla, six of which were previously not known to include MTB. These findings indicate a much wider taxonomic distribution of magnetosome organelle biogenesis across the domain Bacteria than previously thought. Comparative genome analysis reveals a vast diversity of magnetosome gene clusters involved in magnetosomal biogenesis in terms of gene content and synteny residing in distinct taxonomic lineages. Phylogenetic analyses of core magnetosome proteins in this largest available and taxonomically diverse dataset support an unexpectedly early evolutionary origin of magnetosome biomineralization, likely ancestral to the origin of the domain Bacteria. Conclusions These findings expand the taxonomic and phylogenetic diversity of MTB across the domain Bacteria and shed new light on the origin and evolution of microbial magnetoreception. Potential biogenesis of the magnetosome organelle in the close descendants of the last bacterial common ancestor has important implications for our understanding of the evolutionary history of bacterial cellular complexity and emphasizes the biological significance of the magnetosome organelle.


2019 ◽  
Vol 15 ◽  
pp. 117693431987298 ◽  
Author(s):  
Gustavo Caetano-Anollés ◽  
M Fayez Aziz ◽  
Fizza Mughal ◽  
Frauke Gräter ◽  
Ibrahim Koç ◽  
...  

Networks describe how parts associate with each other to form integrated systems which often have modular and hierarchical structure. In biology, network growth involves two processes, one that unifies and the other that diversifies. Here, we propose a biphasic (bow-tie) theory of module emergence. In the first phase, parts are at first weakly linked and associate variously. As they diversify, they compete with each other and are often selected for performance. The emerging interactions constrain their structure and associations. This causes parts to self-organize into modules with tight linkage. In the second phase, variants of the modules diversify and become new parts for a new generative cycle of higher level organization. The paradigm predicts the rise of hierarchical modularity in evolving networks at different timescales and complexity levels. Remarkably, phylogenomic analyses uncover this emergence in the rewiring of metabolomic and transcriptome-informed metabolic networks, the nanosecond dynamics of proteins, and evolving networks of metabolism, elementary functionomes, and protein domain organization.


2014 ◽  
Vol 289 (44) ◽  
pp. 30213-30220 ◽  
Author(s):  
Charles W. Carter

Urzymes are catalysts derived from invariant cores of protein superfamilies. Urzymes from both aminoacyl-tRNA synthetase classes possess sophisticated catalytic mechanisms: pre-steady state bursts, significant transition-state stabilization of both amino acid activation, and tRNA acylation. However, they have insufficient specificity to ensure a fully developed genetic code, suggesting that they participated in synthesizing statistical proteins. They represent a robust experimental platform from which to articulate and test hypotheses both about their own ancestors and about how they, in turn, evolved into modern enzymes. They help reshape numerous paradigms from the RNA World hypothesis to protein structure databases and allostery.


Plants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1980
Author(s):  
Ji-Young Yang ◽  
Mi-Jung Choi ◽  
Seon-Hee Kim ◽  
Hyeok-Jae Choi ◽  
Seung-Chul Kim

The genus Hosta, which has a native distribution in temperate East Asia and a number of species ranging from 23 to 40, represents a taxonomically important and ornamentally popular plant. Despite its taxonomic and horticultural importance, the genus Hosta has remained taxonomically challenging owing to insufficient diagnostic features, continuous morphological variation, and the process of hybridization and introgression, making species circumscription and phylogenetic inference difficult. In this study, we sequenced 11 accessions of Hosta plastomes, including members of three geographically defined subgenera, Hosta, Bryocles, and Giboshi, determined the characteristics of plastomes, and inferred their phylogenetic relationships. We found highly conserved plastomes among the three subgenera, identified several mutation hotspots that can be used as barcodes, and revealed the patterns of codon usage bias and RNA editing sites. Five positively selected plastome genes (rbcL, rpoB, rpoC2, rpl16, and rpl20) were identified. Phylogenetic analysis suggested (1) the earliest divergence of subg. Hosta, (2) non-monophyly of subg. Bryocles and its two sections (Lamellatae and Stoloniferae), (3) a sister relationship between H. sieboldiana (subg. Giboshi) and H. ventricosa (subg. Bryocles), and (4) reciprocally monophyletic and divergent lineages of H. capitata in Korea and Japan, requiring further studies of their taxonomic distinction.


2019 ◽  
Author(s):  
Jiaokun Li ◽  
Tianyuan Gu ◽  
Weimin Zeng ◽  
Runlan Yu ◽  
Yuandong Liu ◽  
...  

Abstract Background: Antimonite [Sb(III)]-oxidizing bacterium have great potential in the environmental bioremediation of Sb-polluted sites. Bacillus sp. S3 isolated from antimony-contaminated soil showed high Sb(III) resistance and Sb(III) oxidation efficiency. However, very little genomic information and evolutionary relationships that bacterial oxidation of Sb(III) is available. Results: Here, we identified a 5579638 bp chromosome with 40.30% GC content and a 241339 bp plasmid with 36.74% GC content in the complete genome of Bacillus sp. S3. Genomic annotation showed that Bacillus sp. S3 contains key aioB gene potentially encoding As(III)/Sb(III) oxidase, is not shared with other Bacillus strains. Further, a series of genes associated with Sb(III) and other heavy metal(loid) were also ascertained, reflecting adaptive advantage for growth in the harsh eco-environment. It is noteworthy that Bacillus sp. S3 is a novel species within the Bacillus genus as indicated by phylogenetic relationship and the average nucleotide identities (ANI) analysis. The presence of genomic plasticity demonstrated a high number of mobile genetic elements (MGEs) that were mainly distributed on chromosomes within the Bacillus genus. The core genome contained 554 core genes and many unique genes were dissected in analyzed genomes, indicating a conserved core but adaptive pan repertoire. Whole genomic alignment indicates that frequently genomic reshuffling and rearrangements, genetic gain and loss, and other recombination events occurred during the evolutionary history of Bacillus genus. In addition, the origin and evolution analysis of Sb(III)-resistance genes revealed that evolutionary relationships and events of horizontal gene transfer (HGT) among the Bacillus genus. The assessment of functionality of heavy metal(loid) resistance genes emphasized its indispensable roles in the harsh eco-environment of Bacillus genus. The real-time Quantitative PCR(RT-qPCR) results of Sb(III)-related genes indicated that the Sb(III) resistance was constantly increased under the Sb(III) stress. Conclusions: The insights provided in this study shed light on the molecular details of Bacillus sp. S3 coping with Sb(III), which extended our understanding on the evolutionary relationship between Bacillus sp. S3 and other closely related species and will enrich the Sb(III) resistance genetic data sources.


2015 ◽  
Vol 1 (8) ◽  
pp. e1500527 ◽  
Author(s):  
Arshan Nasir ◽  
Gustavo Caetano-Anollés

The origin of viruses remains mysterious because of their diverse and patchy molecular and functional makeup. Although numerous hypotheses have attempted to explain viral origins, none is backed by substantive data. We take full advantage of the wealth of available protein structural and functional data to explore the evolution of the proteomic makeup of thousands of cells and viruses. Despite the extremely reduced nature of viral proteomes, we established an ancient origin of the “viral supergroup” and the existence of widespread episodes of horizontal transfer of genetic information. Viruses harboring different replicon types and infecting distantly related hosts shared many metabolic and informational protein structural domains of ancient origin that were also widespread in cellular proteomes. Phylogenomic analysis uncovered a universal tree of life and revealed that modern viruses reduced from multiple ancient cells that harbored segmented RNA genomes and coexisted with the ancestors of modern cells. The model for the origin and evolution of viruses and cells is backed by strong genomic and structural evidence and can be reconciled with existing models of viral evolution if one considers viruses to have originated from ancient cells and not from modern counterparts.


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