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Fry M. The discovery of archaea: from observed anomaly to consequential restructuring of the phylogenetic tree. HISTORY AND PHILOSOPHY OF THE LIFE SCIENCES 2024; 46:16. [PMID: 38530473 PMCID: PMC10965645 DOI: 10.1007/s40656-024-00616-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 02/14/2024] [Indexed: 03/28/2024]
Abstract
Observational and experimental discoveries of new factual entities such as objects, systems, or processes, are major contributors to some advances in the life sciences. Yet, whereas discovery of theories was extensively deliberated by philosophers of science, very little philosophical attention was paid to the discovery of factual entities. This paper examines historical and philosophical aspects of the experimental discovery by Carl Woese of archaea, prokaryotes that comprise one of the three principal domains of the phylogenetic tree. Borrowing Kuhn's terminology, this discovery of a major biological entity was made during a 'normal science' project of building molecular taxonomy for prokaryotes. Unexpectedly, however, an observed anomaly instigated the discovery of archaea. Substantiation of the existence of the new archaeal entity and consequent reconstruction of the phylogenetic tree prompted replacement of a long-held model of a prokarya and eukarya bipartite tree of life by a new model of a tripartite tree comprising of bacteria, archaea, and eukarya. This paper explores the history and philosophical implications of the progression of Woese's project from normal science to anomaly-instigated model-changing discovery. It is also shown that the consequential discoveries of RNA splicing and of ribozymes were similarly prompted by unexpected irregularities during normal science activities. It is thus submitted that some discoveries of factual biological entities are triggered by unforeseen observational or experimental anomalies.
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Affiliation(s)
- Michael Fry
- Department of Biochemistry, Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Efron St., Bat Galim, POB 9649, Haifa, 31096, Israel.
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Lamolle G, Simón D, Iriarte A, Musto H. Main Factors Shaping Amino Acid Usage Across Evolution. J Mol Evol 2023:10.1007/s00239-023-10120-5. [PMID: 37264211 DOI: 10.1007/s00239-023-10120-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/17/2023] [Indexed: 06/03/2023]
Abstract
The standard genetic code determines that in most species, including viruses, there are 20 amino acids that are coded by 61 codons, while the other three codons are stop triplets. Considering the whole proteome each species features its own amino acid frequencies, given the slow rate of change, closely related species display similar GC content and amino acids usage. In contrast, distantly related species display different amino acid frequencies. Furthermore, within certain multicellular species, as mammals, intragenomic differences in the usage of amino acids are evident. In this communication, we shall summarize some of the most prominent and well-established factors that determine the differences found in the amino acid usage, both across evolution and intragenomically.
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Affiliation(s)
- Guillermo Lamolle
- Laboratorio de Genómica Evolutiva, Facultad de Ciencias, Universidad de La República, Montevideo, Uruguay
| | - Diego Simón
- Laboratorio de Genómica Evolutiva, Facultad de Ciencias, Universidad de La República, Montevideo, Uruguay
- Laboratorio de Virología Molecular, Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de La República, Montevideo, Uruguay
- Laboratorio de Evolución Experimental de Virus, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Andrés Iriarte
- Laboratorio de Genómica Evolutiva, Facultad de Ciencias, Universidad de La República, Montevideo, Uruguay
- Laboratorio de Biología Computacional, Departamento de Desarrollo Biotecnológico, Instituto de Higiene, Facultad de Medicina, Universidad de La República, Montevideo, Uruguay
| | - Héctor Musto
- Laboratorio de Genómica Evolutiva, Facultad de Ciencias, Universidad de La República, Montevideo, Uruguay.
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The Origin(s) of Cell(s): Pre-Darwinian Evolution from FUCAs to LUCA : To Carl Woese (1928-2012), for his Conceptual Breakthrough of Cellular Evolution. J Mol Evol 2021; 89:427-447. [PMID: 34173011 DOI: 10.1007/s00239-021-10014-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Accepted: 05/29/2021] [Indexed: 10/21/2022]
Abstract
The coming of the Last Universal Cellular Ancestor (LUCA) was the singular watershed event in the making of the biotic world. If the coming of LUCA marked the crossing of the "Darwinian Threshold", then pre-LUCA evolution must have been Pre-Darwinian and at least partly non-Darwinian. But how did Pre-Darwinian evolution before LUCA actually operate? I broaden our understanding of the central mechanism of biological evolution (i.e., variation-selection-inheritance) and then extend this broadened understanding to its natural starting point: the origin(s) of the First Universal Cellular Ancestors (FUCAs) before LUCA. My hypothesis centers upon vesicles' making-and-remaking as variation and competition as selection. More specifically, I argue that vesicles' acquisition and merger, via breaking-and-repacking, proto-endocytosis, proto-endosymbiosis, and other similar processes had been a central force of both variation and selection in the pre-Darwinian epoch. These new perspectives shed important new light upon the origin of FUCAs and their subsequent evolution into LUCA.
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Algal Toxic Compounds and Their Aeroterrestrial, Airborne and other Extremophilic Producers with Attention to Soil and Plant Contamination: A Review. Toxins (Basel) 2021; 13:toxins13050322. [PMID: 33946968 PMCID: PMC8145420 DOI: 10.3390/toxins13050322] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 04/27/2021] [Accepted: 04/27/2021] [Indexed: 12/16/2022] Open
Abstract
The review summarizes the available knowledge on toxins and their producers from rather disparate algal assemblages of aeroterrestrial, airborne and other versatile extreme environments (hot springs, deserts, ice, snow, caves, etc.) and on phycotoxins as contaminants of emergent concern in soil and plants. There is a growing body of evidence that algal toxins and their producers occur in all general types of extreme habitats, and cyanobacteria/cyanoprokaryotes dominate in most of them. Altogether, 55 toxigenic algal genera (47 cyanoprokaryotes) were enlisted, and our analysis showed that besides the “standard” toxins, routinely known from different waterbodies (microcystins, nodularins, anatoxins, saxitoxins, cylindrospermopsins, BMAA, etc.), they can produce some specific toxic compounds. Whether the toxic biomolecules are related with the harsh conditions on which algae have to thrive and what is their functional role may be answered by future studies. Therefore, we outline the gaps in knowledge and provide ideas for further research, considering, from one side, the health risk from phycotoxins on the background of the global warming and eutrophication and, from the other side, the current surge of interest which phycotoxins provoke due to their potential as novel compounds in medicine, pharmacy, cosmetics, bioremediation, agriculture and all aspects of biotechnological implications in human life.
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Brandis G. Reconstructing the Evolutionary History of a Highly Conserved Operon Cluster in Gammaproteobacteria and Bacilli. Genome Biol Evol 2021; 13:6156628. [PMID: 33677562 PMCID: PMC8046335 DOI: 10.1093/gbe/evab041] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/24/2021] [Indexed: 12/01/2022] Open
Abstract
The evolution of gene order rearrangements within bacterial chromosomes is a fast process. Closely related species can have almost no conservation in long-range gene order. A prominent exception to this rule is a >40 kb long cluster of five core operons (secE-rpoBC-str-S10-spc-alpha) and three variable adjacent operons (cysS, tufB, and ecf) that together contain 57 genes of the transcriptional and translational machinery. Previous studies have indicated that at least part of this operon cluster might have been present in the last common ancestor of bacteria and archaea. Using 204 whole genome sequences, ∼2 Gy of evolution of the operon cluster were reconstructed back to the last common ancestors of the Gammaproteobacteria and of the Bacilli. A total of 163 independent evolutionary events were identified in which the operon cluster was altered. Further examination showed that the process of disconnecting two operons generally follows the same pattern. Initially, a small number of genes is inserted between the operons breaking the concatenation followed by a second event that fully disconnects the operons. While there is a general trend for loss of gene synteny over time, there are examples of increased alteration rates at specific branch points or within specific bacterial orders. This indicates the recurrence of relaxed selection on the gene order within bacterial chromosomes. The analysis of the alternation events indicates that segmental genome duplications and/or transposon-directed recombination play a crucial role in rearrangements of the operon cluster.
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Affiliation(s)
- Gerrit Brandis
- Department of Cell and Molecular Biology, Uppsala University, Biomedical Center, Sweden
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Purkait D, Bandyopadhyay D, Mishra PP. Vital insights into prokaryotic genome compaction by nucleoid-associated protein (NAP) and illustration of DNA flexure angles at single-molecule resolution. Int J Biol Macromol 2021; 171:100-111. [PMID: 33418050 DOI: 10.1016/j.ijbiomac.2020.12.194] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 12/24/2020] [Accepted: 12/25/2020] [Indexed: 11/20/2022]
Abstract
Integration Host Factor (IHF) is a heterodimeric site-specific nucleoid-associated protein (NAP), well known for its DNA bending ability. Although the IHF induced bending states of DNA have been captured by both X-ray Crystallography and Atomic Force Microscopy (AFM), the range of flexibility and degree of heterogeneity in terms of quantitative analysis of the nucleoprotein complex has largely remained unexplored. Binding of IHF leads to introduction of two kinks in the dsDNA that allowed us to come up with a quadrilateral model. The findings have further been extended by calculating the angles of flexibility, that gives the idea of the degree of dynamicity of the nucleoprotein complex. We have monitored and compared the trajectories of the conformational dynamics of a dsDNA upon binding of wild-type (wt) and single-chain (sc) IHF at millisecond resolution through single-molecule FRET (smFRET). Our findings reveal that the nucleoprotein complex exists in a 'Slacked-Dynamic' state throughout the observation window where many of them have switched between multiple 'Wobbling States' in the course of attainment of packaged form. This study opens up an opportunity to improve the understanding of the functions of other nucleoid-associated proteins (NAPs) by complementing the previous detailed atomic-level structural analysis, which eventually will allow accessibility towards a better hypothesis.
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Affiliation(s)
- Debayan Purkait
- Single Molecule Biophysics Lab, Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, India; Homi Bhaba National Institute (HBNI), Mumbai, India
| | - Debolina Bandyopadhyay
- Single Molecule Biophysics Lab, Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, India; Homi Bhaba National Institute (HBNI), Mumbai, India
| | - Padmaja P Mishra
- Single Molecule Biophysics Lab, Chemical Sciences Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata, India; Homi Bhaba National Institute (HBNI), Mumbai, India.
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Brandis G, Hughes D. The SNAP hypothesis: Chromosomal rearrangements could emerge from positive Selection during Niche Adaptation. PLoS Genet 2020; 16:e1008615. [PMID: 32130223 PMCID: PMC7055797 DOI: 10.1371/journal.pgen.1008615] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 01/17/2020] [Indexed: 12/23/2022] Open
Abstract
The relative linear order of most genes on bacterial chromosomes is not conserved over evolutionary timescales. One explanation is that selection is weak, allowing recombination to randomize gene order by genetic drift. However, most chromosomal rearrangements are deleterious to fitness. In contrast, we propose the hypothesis that rearrangements in gene order are more likely the result of selection during niche adaptation (SNAP). Partial chromosomal duplications occur very frequently by recombination between direct repeat sequences. Duplicated regions may contain tens to hundreds of genes and segregate quickly unless maintained by selection. Bacteria exposed to non-lethal selections (for example, a requirement to grow on a poor nutrient) can adapt by maintaining a duplication that includes a gene that improves relative fitness. Further improvements in fitness result from the loss or inactivation of non-selected genes within each copy of the duplication. When genes that are essential in single copy are lost from different copies of the duplication, segregation is prevented even if the original selection is lifted. Functional gene loss continues until a new genetic equilibrium is reached. The outcome is a rearranged gene order. Mathematical modelling shows that this process of positive selection to adapt to a new niche can rapidly drive rearrangements in gene order to fixation. Signature features (duplication formation and divergence) of the SNAP model were identified in natural isolates from multiple species showing that the initial two steps in the SNAP process can occur with a remarkably high frequency. Further bioinformatic and experimental analyses are required to test if and to which extend the SNAP process acts on bacterial genomes. All life on earth has evolved from a universal common ancestor with a specific order of genes on the chromosome. This order is not maintained in modern species and the standard hypothesis is that changes reflect a lack of strong selection on gene order. Here, we propose an alternative hypothesis, SNAP. The occupation of a novel environment by bacteria is generally a trade-off situation. For example, while the bacteria may not be adapted to grow well under the new conditions, they may benefit by not having to share available resources with other microorganisms. Bacterial populations frequently acquire duplications of chromosomal segments containing genes that can help them adapt to a new environment. Other genes that are also duplicated are not required in two copies so that over time a superfluous copy can be lost. Eventually, the process of duplication and gene loss can lead to the rearrangement of the gene order in the chromosomal segment. The major benefit of this model over the standard hypothesis is that the process is driven by positive selection and can reach fixation rapidly.
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Affiliation(s)
- Gerrit Brandis
- Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Uppsala, Sweden
| | - Diarmaid Hughes
- Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala University, Uppsala, Sweden
- * E-mail:
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Papale F, Saget J, Bapteste É. Networks Consolidate the Core Concepts of Evolution by Natural Selection. Trends Microbiol 2019; 28:254-265. [PMID: 31866140 DOI: 10.1016/j.tim.2019.11.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 11/12/2019] [Accepted: 11/18/2019] [Indexed: 02/07/2023]
Abstract
Microbiology has unraveled rich evidence of ongoing reticulate evolutionary processes and complex interactions both within and between cells. These phenomena feature real biological networks, which can logically be analyzed using network-based tools. It is thus not surprising that network sciences, a field independent from evolutionary biology and microbiology, have recently pervasively infused their methods into both fields. Importantly, network tools bring forward observations enhancing the understanding of three core evolutionary concepts: variation, fitness, and heredity. Consequently, our work shows how network sciences can enhance evolutionary theory by explaining the evolution by natural selection of a broad diversity of units of selection, while updating the popular figure of Darwin's tree of life with a comprehensive sketch of the networks of evolution.
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Affiliation(s)
- François Papale
- Departement of Philosophy, University of Montreal, Montréal, QC, H3C 3J7, Canada; Institut de Systématique, Evolution, Biodiversité (ISYEB), Sorbonne Université, CNRS, Museum National d'Histoire Naturelle, EPHE, Université des Antilles, 75005 Paris, France
| | - Jordane Saget
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Sorbonne Université, CNRS, Museum National d'Histoire Naturelle, EPHE, Université des Antilles, 75005 Paris, France
| | - Éric Bapteste
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Sorbonne Université, CNRS, Museum National d'Histoire Naturelle, EPHE, Université des Antilles, 75005 Paris, France.
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On the possible origin of protein homochirality, structure, and biochemical function. Proc Natl Acad Sci U S A 2019; 116:26571-26579. [PMID: 31822617 DOI: 10.1073/pnas.1908241116] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Living systems have chiral molecules, e.g., native proteins that almost entirely contain L-amino acids. How protein homochirality emerged from a background of equal numbers of L and D amino acids is among many questions about life's origin. The origin of homochirality and its implications are explored in computer simulations examining the stability and structural and functional properties of an artificial library of compact proteins containing 1:1 (termed demi-chiral), 3:1, and 1:3 ratios of D:L and purely L or D amino acids generated without functional selection. Demi-chiral proteins have shorter secondary structures and fewer internal hydrogen bonds and are less stable than homochiral proteins. Selection for hydrogen bonding yields a preponderance of L or D amino acids. Demi-chiral proteins have native global folds, including similarity to early ribosomal proteins, similar small molecule ligand binding pocket geometries, and many constellations of L-chiral amino acids with a 1.0-Å RMSD to native enzyme active sites. For a representative subset containing 550 active site geometries matching 457 (2) 4-digit (3-digit) enzyme classification (E.C.) numbers, native active site amino acids were generated at random for 472 of 550 cases. This increases to 548 of 550 cases when similar residues are allowed. The most frequently generated sequences correspond to ancient enzymatic functions, e.g., glycolysis, replication, and nucleotide biosynthesis. Surprisingly, even without selection, demi-chiral proteins possess the requisite marginal biochemical function and structure of modern proteins, but were thermodynamically less stable. If demi-chiral proteins were present, they could engage in early metabolism, which created the feedback loop for transcription and cell formation.
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Steel M, Kauffman S. A note on random catalytic branching processes. J Theor Biol 2018; 437:222-224. [PMID: 29080779 DOI: 10.1016/j.jtbi.2017.10.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Revised: 08/29/2017] [Accepted: 10/22/2017] [Indexed: 01/30/2023]
Abstract
A variety of evolutionary processes in biology can be viewed as settings where organisms 'catalyse' the formation of new types of organisms. One example, relevant to the origin of life, is where transient biological colonies (e.g. prokaryotes or protocells) give rise to new colonies via lateral gene transfer. In this short note, we describe and analyse a simple random process which models such settings. By applying theory from general birth-death processes, we describe how the survival of a population under catalytic diversification depends on interplay of the catalysis rate and the initial population size. We also note how such process can also be viewed within the framework of 'self-sustaining autocatalytic networks'.
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Affiliation(s)
- Mike Steel
- Biomathematics Research Centre, University of Canterbury, Christchurch, New Zealand.
| | - Stuart Kauffman
- Affiliate Professor Institute for Systems Biology Emeritus Professor Biochemistry and Biophysics University of Pennsylavania, PA, USA
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Froese T, Campos JI, Fujishima K, Kiga D, Virgo N. Horizontal transfer of code fragments between protocells can explain the origins of the genetic code without vertical descent. Sci Rep 2018; 8:3532. [PMID: 29476089 PMCID: PMC5824800 DOI: 10.1038/s41598-018-21973-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 02/14/2018] [Indexed: 11/09/2022] Open
Abstract
Theories of the origin of the genetic code typically appeal to natural selection and/or mutation of hereditable traits to explain its regularities and error robustness, yet the present translation system presupposes high-fidelity replication. Woese's solution to this bootstrapping problem was to assume that code optimization had played a key role in reducing the effect of errors caused by the early translation system. He further conjectured that initially evolution was dominated by horizontal exchange of cellular components among loosely organized protocells ("progenotes"), rather than by vertical transmission of genes. Here we simulated such communal evolution based on horizontal transfer of code fragments, possibly involving pairs of tRNAs and their cognate aminoacyl tRNA synthetases or a precursor tRNA ribozyme capable of catalysing its own aminoacylation, by using an iterated learning model. This is the first model to confirm Woese's conjecture that regularity, optimality, and (near) universality could have emerged via horizontal interactions alone.
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Affiliation(s)
- Tom Froese
- Institute for Applied Mathematics and Systems Research (IIMAS), National Autonomous University of Mexico (UNAM), Mexico City, 04510, Mexico. .,Center for the Sciences of Complexity (C3), National Autonomous University of Mexico (UNAM), Mexico City, 04510, Mexico.
| | - Jorge I Campos
- Center for the Sciences of Complexity (C3), National Autonomous University of Mexico (UNAM), Mexico City, 04510, Mexico.,Faculty of Higher Education Aragon, National Autonomous University of Mexico (UNAM), Nezahualcoyotl City, State of Mexico, 57130, Mexico
| | - Kosuke Fujishima
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8550, Japan.,Institute for Advanced Biosciences, Keio University, Tsuruoka, 9970035, Japan
| | - Daisuke Kiga
- Faculty of Science and Engineering, School of Advanced Science and Engineering, Waseda University, Shinjuku, Tokyo, 169-8555, Japan
| | - Nathaniel Virgo
- Earth-Life Science Institute, Tokyo Institute of Technology, Meguro-ku, Tokyo, 152-8550, Japan
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Saha RP, Samanta S, Patra S, Sarkar D, Saha A, Singh MK. Metal homeostasis in bacteria: the role of ArsR-SmtB family of transcriptional repressors in combating varying metal concentrations in the environment. Biometals 2017; 30:459-503. [PMID: 28512703 DOI: 10.1007/s10534-017-0020-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 05/09/2017] [Indexed: 02/02/2023]
Abstract
Bacterial infections cause severe medical problems worldwide, resulting in considerable death and loss of capital. With the ever-increasing rise of antibiotic-resistant bacteria and the lack of development of new antibiotics, research on metal-based antimicrobial therapy has now gained pace. Metal ions are essential for survival, but can be highly toxic to organisms if their concentrations are not strictly controlled. Through evolution, bacteria have acquired complex metal-management systems that allow them to acquire metals that they need for survival in different challenging environments while evading metal toxicity. Metalloproteins that controls these elaborate systems in the cell, and linked to key virulence factors, are promising targets for the anti-bacterial drug development. Among several metal-sensory transcriptional regulators, the ArsR-SmtB family displays greatest diversity with several distinct metal-binding and nonmetal-binding motifs that have been characterized. These prokaryotic metolloregulatory transcriptional repressors represses the expression of operons linked to stress-inducing concentrations of metal ions by directly binding to the regulatory regions of DNA, while derepression results from direct binding of metal ions by these homodimeric proteins. Many bacteria, e.g., Mycobacterium tuberculosis, Bacillus anthracis, etc., have evolved to acquire multiple metal-sensory motifs which clearly demonstrate the importance of regulating concentrations of multiple metal ions. Here, we discussed the mechanisms of how ArsR-SmtB family regulates the intracellular bioavailability of metal ions both inside and outside of the host. Knowledge of the metal-challenges faced by bacterial pathogens and their survival strategies will enable us to develop the next generation drugs.
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Affiliation(s)
- Rudra P Saha
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India.
| | - Saikat Samanta
- Department of Microbiology, School of Science, Adamas University, Kolkata, 700126, India
| | - Surajit Patra
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India
| | - Diganta Sarkar
- Department of Biotechnology, Techno India University, Kolkata, 700091, India
| | - Abinit Saha
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India
| | - Manoj Kumar Singh
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India
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Emergence of Life on Earth: A Physicochemical Jigsaw Puzzle. J Mol Evol 2016; 84:1-7. [PMID: 27995274 DOI: 10.1007/s00239-016-9775-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2016] [Accepted: 11/29/2016] [Indexed: 10/20/2022]
Abstract
We review physicochemical factors and processes that describe how cellular life can emerge from prebiotic chemical matter; they are: (1) prebiotic Earth is a multicomponent and multiphase reservoir of chemical compounds, to which (2) Earth-Moon rotations deliver two kinds of regular cycling energies: diurnal electromagnetic radiation and seawater tides. (3) Emerging colloidal phases cyclically nucleate and agglomerate in seawater and consolidate as geochemical sediments in tidal zones, creating a matrix of microspaces. (4) Some microspaces persist and retain memory from past cycles, and others re-dissolve and re-disperse back into the Earth's chemical reservoir. (5) Proto-metabolites and proto-biopolymers coevolve with and within persisting microspaces, where (6) Macromolecular crowding and other non-covalent molecular forces govern the evolution of hydrophilic, hydrophobic, and charged molecular surfaces. (7) The matrices of microspaces evolve into proto-biofilms of progenotes with rudimentary but evolving replication, transcription, and translation, enclosed in unstable cell envelopes. (8) Stabilization of cell envelopes 'crystallizes' bacteria-like genetics and metabolism with low horizontal gene transfer-life 'as we know it.' These factors and processes constitute the 'working pieces' of the jigsaw puzzle of life's emergence. They extend the concept of progenotes as the first proto-cellular life, connected backward in time to the cycling chemistries of the Earth-Moon planetary system, and forward to the ancient cell cycle of first bacteria-like organisms. Supra-macromolecular models of 'compartments first' are preferred: they facilitate macromolecular crowding-a key abiotic/biotic transition toward living states. Evolutionary models of metabolism or genetics 'first' could not have evolved in unconfined and uncrowded environments because of the diffusional drift to disorder mandated by the second law of thermodynamics.
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Hladilek MD, Gaines KF, Novak JM, Collard DA, Johnson DB, Canam T. Microbial community structure of a freshwater system receiving wastewater effluent. ENVIRONMENTAL MONITORING AND ASSESSMENT 2016; 188:626. [PMID: 27761851 DOI: 10.1007/s10661-016-5630-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 10/05/2016] [Indexed: 06/06/2023]
Abstract
Despite our dependency on treatment facilities to condition wastewater for eventual release to the environment, our knowledge regarding the effects of treated water on the local watershed is extremely limited. Responses of lotic systems to the treated wastewater effluent have been traditionally investigated by examining the benthic macroinvertebrate assemblages and community structure; however, these studies do not address the microbial diversity of the water systems. In the present study, planktonic and benthic bacterial community structure were examined at 14 sites (from 60 m upstream to 12,100 m downstream) and at two time points along an aquatic system receiving treated effluent from the Charleston Wastewater Treatment Plant (Charleston, IL). Total bacterial DNA was isolated and 16S rRNA sequences were analyzed using a metagenomics platform. The community structure in planktonic bacterial communities was significantly correlated with dissolved oxygen concentration. Benthic bacterial communities were not correlated with water quality but did have a significant geographic structuring. A local restructuring effect was observed in both planktonic and benthic communities near the treated wastewater effluent, which was characterized by an increase in abundance of sphingobacteria. Sites further downstream from the wastewater facility appeared to be less influenced by the effluent. Overall, the present study demonstrated the utility of targeted high-throughput sequencing as a tool to assess the effects of treated wastewater effluent on a receiving water system, and highlighted the potential for this technology to be used for routine monitoring by wastewater facilities.
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Affiliation(s)
- Matthew D Hladilek
- Department of Biological Sciences, Eastern Illinois University, Charleston, IL, USA
| | - Karen F Gaines
- Department of Biological Sciences, Eastern Illinois University, Charleston, IL, USA
| | - James M Novak
- Department of Biological Sciences, Eastern Illinois University, Charleston, IL, USA
| | - David A Collard
- Public Works Department, Wastewater Treatment, Charleston, IL, USA
| | - Daniel B Johnson
- Department of Biological Sciences, Eastern Illinois University, Charleston, IL, USA
- OneWater Incorporated, Indianapolis, IN, USA
| | - Thomas Canam
- Department of Biological Sciences, Eastern Illinois University, Charleston, IL, USA.
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16
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Population-specific renal proteomes of marine and freshwater three-spined sticklebacks. J Proteomics 2016; 135:112-131. [DOI: 10.1016/j.jprot.2015.10.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 09/16/2015] [Accepted: 10/02/2015] [Indexed: 12/20/2022]
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17
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Baer B, Millar AH. Proteomics in evolutionary ecology. J Proteomics 2015; 135:4-11. [PMID: 26453985 DOI: 10.1016/j.jprot.2015.09.031] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 09/22/2015] [Accepted: 09/30/2015] [Indexed: 01/09/2023]
Abstract
Evolutionary ecologists are traditionally gene-focused, as genes propagate phenotypic traits across generations and mutations and recombination in the DNA generate genetic diversity required for evolutionary processes. As a consequence, the inheritance of changed DNA provides a molecular explanation for the functional changes associated with natural selection. A direct focus on proteins on the other hand, the actual molecular agents responsible for the expression of a phenotypic trait, receives far less interest from ecologists and evolutionary biologists. This is partially due to the central dogma of molecular biology that appears to define proteins as the 'dead-end of molecular information flow' as well as technical limitations in identifying and studying proteins and their diversity in the field and in many of the more exotic genera often favored in ecological studies. Here we provide an overview of a newly forming field of research that we refer to as 'Evolutionary Proteomics'. We point out that the origins of cellular function are related to the properties of polypeptide and RNA and their interactions with the environment, rather than DNA descent, and that the critical role of horizontal gene transfer in evolution is more about coopting new proteins to impact cellular processes than it is about modifying gene function. Furthermore, post-transcriptional and post-translational processes generate a remarkable diversity of mature proteins from a single gene, and the properties of these mature proteins can also influence inheritance through genetic and perhaps epigenetic mechanisms. The influence of post-transcriptional diversification on evolutionary processes could provide a novel mechanistic underpinning for elements of rapid, directed evolutionary changes and adaptations as observed for a variety of evolutionary processes. Modern state-of the art technologies based on mass spectrometry are now available to identify and quantify peptides, proteins, protein modifications and protein interactions of interest with high accuracy and assess protein diversity and function. Therefore, proteomic technologies can be viewed as providing evolutionary biologist with exciting novel opportunities to understand very early events in functional variation of cellular molecular machinery that are acting as part of evolutionary processes.
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Affiliation(s)
- B Baer
- Centre for Integrative Bee Research (CIBER) and ARC Centre of Excellence in Plant Energy Biology, Bayliss Building, The University of Western Australia, 6009 Crawley, Australia.
| | - A H Millar
- Centre for Integrative Bee Research (CIBER) and ARC Centre of Excellence in Plant Energy Biology, Bayliss Building, The University of Western Australia, 6009 Crawley, Australia
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18
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Black Queen evolution: the role of leakiness in structuring microbial communities. Trends Genet 2015; 31:475-82. [DOI: 10.1016/j.tig.2015.05.004] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 05/11/2015] [Accepted: 05/12/2015] [Indexed: 11/21/2022]
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19
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Spitzer J, Pielak GJ, Poolman B. Emergence of life: Physical chemistry changes the paradigm. Biol Direct 2015; 10:33. [PMID: 26059688 PMCID: PMC4460864 DOI: 10.1186/s13062-015-0060-y] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 05/14/2015] [Indexed: 12/02/2022] Open
Abstract
Origin of life research has been slow to advance not only because of its complex evolutionary nature (Franklin Harold: In Search of Cell History, 2014) but also because of the lack of agreement on fundamental concepts, including the question of ‘what is life?’. To re-energize the research and define a new experimental paradigm, we advance four premises to better understand the physicochemical complexities of life’s emergence:Chemical and Darwinian (biological) evolutions are distinct, but become continuous with the appearance of heredity. Earth’s chemical evolution is driven by energies of cycling (diurnal) disequilibria and by energies of hydrothermal vents. Earth’s overall chemical complexity must be high at the origin of life for a subset of (complex) chemicals to phase separate and evolve into living states. Macromolecular crowding in aqueous electrolytes under confined conditions enables evolution of molecular recognition and cellular self-organization.
We discuss these premises in relation to current ‘constructive’ (non-evolutionary) paradigm of origins research – the process of complexification of chemical matter ‘from the simple to the complex’. This paradigm artificially avoids planetary chemical complexity and the natural tendency of molecular compositions toward maximum disorder embodied in the second law of thermodynamics. Our four premises suggest an empirical program of experiments involving complex chemical compositions under cycling gradients of temperature, water activity and electromagnetic radiation.
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Affiliation(s)
- Jan Spitzer
- R&D Department, Mallard Creek Polymers, Inc., 2800 Morehead Rd, Charlotte, NC, 28262, USA.
| | - Gary J Pielak
- Department of Chemistry, Department of Biochemistry and Biophysics and Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, 27599, USA.
| | - Bert Poolman
- Department of Biochemistry, Groningen Biomolecular Sciences and Biotechnology Institute & Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747, AG, Groningen, The Netherlands.
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20
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Jalasvuori M, Mattila S, Hoikkala V. Chasing the Origin of Viruses: Capsid-Forming Genes as a Life-Saving Preadaptation within a Community of Early Replicators. PLoS One 2015; 10:e0126094. [PMID: 25955384 PMCID: PMC4425637 DOI: 10.1371/journal.pone.0126094] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 03/29/2015] [Indexed: 12/31/2022] Open
Abstract
Virus capsids mediate the transfer of viral genetic information from one cell to another, thus the origin of the first viruses arguably coincides with the origin of the viral capsid. Capsid genes are evolutionarily ancient and their emergence potentially predated even the origin of first free-living cells. But does the origin of the capsid coincide with the origin of viruses, or is it possible that capsid-like functionalities emerged before the appearance of true viral entities? We set to investigate this question by using a computational simulator comprising primitive replicators and replication parasites within a compartment matrix. We observe that systems with no horizontal gene transfer between compartments collapse due to the rapidly emerging replication parasites. However, introduction of capsid-like genes that induce the movement of randomly selected genes from one compartment to another rescues life by providing the non-parasitic replicators a mean to escape their current compartments before the emergence of replication parasites. Capsid-forming genes can mediate the establishment of a stable meta-population where parasites cause only local tragedies but cannot overtake the whole community. The long-term survival of replicators is dependent on the frequency of horizontal transfer events, as systems with either too much or too little genetic exchange are doomed to succumb to replication-parasites. This study provides a possible scenario for explaining the origin of viral capsids before the emergence of genuine viruses: in the absence of other means of horizontal gene transfer between compartments, evolution of capsid-like functionalities may have been necessary for early life to prevail.
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Affiliation(s)
- Matti Jalasvuori
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
- * E-mail:
| | - Sari Mattila
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
| | - Ville Hoikkala
- Centre of Excellence in Biological Interactions, Department of Biological and Environmental Science, University of Jyväskylä, Jyväskylä, Finland
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21
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Archaeal Clusters of Orthologous Genes (arCOGs): An Update and Application for Analysis of Shared Features between Thermococcales, Methanococcales, and Methanobacteriales. Life (Basel) 2015; 5:818-40. [PMID: 25764277 PMCID: PMC4390880 DOI: 10.3390/life5010818] [Citation(s) in RCA: 140] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Revised: 02/25/2015] [Accepted: 02/28/2015] [Indexed: 11/18/2022] Open
Abstract
With the continuously accelerating genome sequencing from diverse groups of archaea and bacteria, accurate identification of gene orthology and availability of readily expandable clusters of orthologous genes are essential for the functional annotation of new genomes. We report an update of the collection of archaeal Clusters of Orthologous Genes (arCOGs) to cover, on average, 91% of the protein-coding genes in 168 archaeal genomes. The new arCOGs were constructed using refined algorithms for orthology identification combined with extensive manual curation, including incorporation of the results of several completed and ongoing research projects in archaeal genomics. A new level of classification is introduced, superclusters that unit two or more arCOGs and more completely reflect gene family evolution than individual, disconnected arCOGs. Assessment of the current archaeal genome annotation in public databases indicates that consistent use of arCOGs can significantly improve the annotation quality. In addition to their utility for genome annotation, arCOGs also are a platform for phylogenomic analysis. We explore this aspect of arCOGs by performing a phylogenomic study of the Thermococci that are traditionally viewed as the basal branch of the Euryarchaeota. The results of phylogenomic analysis that involved both comparison of multiple phylogenetic trees and a search for putative derived shared characters by using phyletic patterns extracted from the arCOGs reveal a likely evolutionary relationship between the Thermococci, Methanococci, and Methanobacteria. The arCOGs are expected to be instrumental for a comprehensive phylogenomic study of the archaea.
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22
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Georgescu R, Langston L, O'Donnell M. A proposal: Evolution of PCNA's role as a marker of newly replicated DNA. DNA Repair (Amst) 2015; 29:4-15. [PMID: 25704660 DOI: 10.1016/j.dnarep.2015.01.015] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Revised: 01/28/2015] [Accepted: 01/30/2015] [Indexed: 11/26/2022]
Abstract
Processivity clamps that hold DNA polymerases to DNA for processivity were the first proteins known to encircle the DNA duplex. At the time, polymerase processivity was thought to be the only function of ring shaped processivity clamps. But studies from many laboratories have identified numerous proteins that bind and function with sliding clamps. Among these processes are mismatch repair and nucleosome assembly. Interestingly, there exist polymerases that are highly processive and do not require clamps. Hence, DNA polymerase processivity does not intrinsically require that sliding clamps evolved for this purpose. We propose that polymerases evolved to require clamps as a way of ensuring that clamps are deposited on newly replicated DNA. These clamps are then used on the newly replicated daughter strands, for processes important to genomic integrity, such as mismatch repair and the assembly of nucleosomes to maintain epigenetic states of replicating cells during development.
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Affiliation(s)
- Roxana Georgescu
- Rockefeller University and HHMI, 1230 York Avenue, Box 228, New York, NY 10065, United States
| | - Lance Langston
- Rockefeller University and HHMI, 1230 York Avenue, Box 228, New York, NY 10065, United States
| | - Mike O'Donnell
- Rockefeller University and HHMI, 1230 York Avenue, Box 228, New York, NY 10065, United States.
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23
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The relative ages of eukaryotes and akaryotes. J Mol Evol 2014; 79:228-39. [PMID: 25179144 DOI: 10.1007/s00239-014-9643-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2014] [Accepted: 08/18/2014] [Indexed: 12/22/2022]
Abstract
The Last Eukaryote Common Ancestor (LECA) appears to have the genetics required for meiosis, mitosis, nucleus and nuclear substructures, an exon/intron gene structure, spliceosomes, many centres of DNA replication, etc. (and including mitochondria). Most of these features are not generally explained by models for the origin of the Eukaryotic cell based on the fusion of an Archeon and a Bacterium. We find that the term 'prokaryote' is ambiguous and the non-phylogenetic term akaryote should be used in its place because we do not yet know the direction of evolution between eukaryotes and akaryotes. We use the term 'protoeukaryote' for the hypothetical stem group ancestral eukaryote that took up a bacterium as an endosymbiont that formed the mitochondrion. It is easier to make detailed models with a eukaryote to an akaryote transition, rather than vice versa. So we really are at a phylogenetic impasse in not being confident about the direction of change between eukaryotes and akaryotes.
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Abstract
All life on earth can be naturally classified into cellular life forms and virus-like selfish elements, the latter being fully dependent on the former for their reproduction. Cells are reproducers that not only replicate their genome but also reproduce the cellular organization that depends on semipermeable, energy-transforming membranes and cannot be recovered from the genome alone, under the famous dictum of Rudolf Virchow, Omnis cellula e cellula. In contrast, simple selfish elements are replicators that can complete their life cycles within the host cell starting from genomic RNA or DNA alone. The origin of the cellular organization is the central and perhaps the hardest problem of evolutionary biology. I argue that the origin of cells can be understood only in conjunction with the origin and evolution of selfish genetic elements. A scenario of precellular evolution is presented that involves cohesion of the genomes of the emerging cellular life forms from primordial pools of small genetic elements that eventually segregated into hosts and parasites. I further present a model of the coevolution of primordial membranes and membrane proteins, discuss protocellular and non-cellular models of early evolution, and examine the habitats on the primordial earth that could have been conducive to precellular evolution and the origin of cells.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, National Institute of Health, Bethesda, MD, 20894, USA,
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