1
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Hörandl E. Apomixis and the paradox of sex in plants. ANNALS OF BOTANY 2024; 134:1-18. [PMID: 38497809 PMCID: PMC11161571 DOI: 10.1093/aob/mcae044] [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: 12/11/2023] [Accepted: 03/15/2024] [Indexed: 03/19/2024]
Abstract
BACKGROUND The predominance of sex in eukaryotes, despite the high costs of meiosis and mating, remains an evolutionary enigma. Many theories have been proposed, none of them being conclusive on its own, and they are, in part, not well applicable to land plants. Sexual reproduction is obligate in embryophytes for the great majority of species. SCOPE This review compares the main forms of sexual and asexual reproduction in ferns and angiosperms, based on the generation cycling of sporophyte and gametophyte (leaving vegetative propagation aside). The benefits of sexual reproduction for maintenance of genomic integrity in comparison to asexuality are discussed in the light of developmental, evolutionary, genetic and phylogenetic studies. CONCLUSIONS Asexual reproduction represents modifications of the sexual pathway, with various forms of facultative sexuality. For sexual land plants, meiosis provides direct DNA repair mechanisms for oxidative damage in reproductive tissues. The ploidy alternations of meiosis-syngamy cycles and prolonged multicellular stages in the haploid phase in the gametophytes provide a high efficiency of purifying selection against recessive deleterious mutations. Asexual lineages might buffer effects of such mutations via polyploidy and can purge the mutational load via facultative sexuality. The role of organelle-nuclear genome compatibility for maintenance of genome integrity is not well understood. In plants in general, the costs of mating are low because of predominant hermaphroditism. Phylogenetic patterns in the archaeplastid clade suggest that high frequencies of sexuality in land plants are concomitant with a stepwise increase of intrinsic and extrinsic stress factors. Furthermore, expansion of genome size in land plants would increase the potential mutational load. Sexual reproduction appears to be essential for keeping long-term genomic integrity, and only rare combinations of extrinsic and intrinsic factors allow for shifts to asexuality.
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Affiliation(s)
- Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with herbarium), University of Göttingen, Göttingen, Germany
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2
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da Silva VS, Machado CR. Sex in protists: A new perspective on the reproduction mechanisms of trypanosomatids. Genet Mol Biol 2022; 45:e20220065. [PMID: 36218381 PMCID: PMC9552303 DOI: 10.1590/1678-4685-gmb-2022-0065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 08/07/2022] [Indexed: 11/04/2022] Open
Abstract
The Protist kingdom individuals are the most ancestral representatives of
eukaryotes. They have inhabited Earth since ancient times and are currently
found in the most diverse environments presenting a great heterogeneity of life
forms. The unicellular and multicellular algae, photosynthetic and heterotrophic
organisms, as well as free-living and pathogenic protozoa represents the protist
group. The evolution of sex is directly associated with the origin of eukaryotes
being protists the earliest protagonists of sexual reproduction on earth. In
eukaryotes, the recombination through genetic exchange is a ubiquitous mechanism
that can be stimulated by DNA damage. Scientific evidences support the
hypothesis that reactive oxygen species (ROS) induced DNA damage can promote
sexual recombination in eukaryotes which might have been a decisive factor for
the origin of sex. The fact that some recombination enzymes also participate in
meiotic sex in modern eukaryotes reinforces the idea that sexual reproduction
emerged as consequence of specific mechanisms to cope with mutations and
alterations in genetic material. In this review we will discuss about origin of
sex and different strategies of evolve sexual reproduction in some protists such
that cause human diseases like malaria, toxoplasmosis, sleeping sickness, Chagas
disease, and leishmaniasis.
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Affiliation(s)
- Verônica Santana da Silva
- Universidade Federal de Minas Gerais, Departamento de Genética,
Ecologia e Evolução, Belo Horizonte, MG, Brazil
| | - Carlos Renato Machado
- Universidade Federal de Minas Gerais, Departamento de Bioquímica e
Imunologia, Belo Horizonte, MG, Brazil
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3
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Foe VE. Does the Pachytene Checkpoint, a Feature of Meiosis, Filter Out Mistakes in Double-Strand DNA Break Repair and as a side-Effect Strongly Promote Adaptive Speciation? Integr Org Biol 2022; 4:obac008. [PMID: 36827645 PMCID: PMC8998493 DOI: 10.1093/iob/obac008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
This essay aims to explain two biological puzzles: why eukaryotic transcription units are composed of short segments of coding DNA interspersed with long stretches of non-coding (intron) DNA, and the near ubiquity of sexual reproduction. As is well known, alternative splicing of its coding sequences enables one transcription unit to produce multiple variants of each encoded protein. Additionally, padding transcription units with non-coding DNA (often many thousands of base pairs long) provides a readily evolvable way to set how soon in a cell cycle the various mRNAs will begin being expressed and the total amount of mRNA that each transcription unit can make during a cell cycle. This regulation complements control via the transcriptional promoter and facilitates the creation of complex eukaryotic cell types, tissues, and organisms. However, it also makes eukaryotes exceedingly vulnerable to double-strand DNA breaks, which end-joining break repair pathways can repair incorrectly. Transcription units cover such a large fraction of the genome that any mis-repair producing a reorganized chromosome has a high probability of destroying a gene. During meiosis, the synaptonemal complex aligns homologous chromosome pairs and the pachytene checkpoint detects, selectively arrests, and in many organisms actively destroys gamete-producing cells with chromosomes that cannot adequately synapse; this creates a filter favoring transmission to the next generation of chromosomes that retain the parental organization, while selectively culling those with interrupted transcription units. This same meiotic checkpoint, reacting to accidental chromosomal reorganizations inflicted by error-prone break repair, can, as a side effect, provide a mechanism for the formation of new species in sympatry. It has been a long-standing puzzle how something as seemingly maladaptive as hybrid sterility between such new species can arise. I suggest that this paradox is resolved by understanding the adaptive importance of the pachytene checkpoint, as outlined above.
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4
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Louradour I, Ferreira TR, Duge E, Karunaweera N, Paun A, Sacks D. Stress conditions promote Leishmania hybridization in vitro marked by expression of the ancestral gamete fusogen HAP2 as revealed by single-cell RNA-seq. eLife 2022; 11:73488. [PMID: 34994687 PMCID: PMC8794473 DOI: 10.7554/elife.73488] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 01/06/2022] [Indexed: 12/18/2022] Open
Abstract
Leishmania are protozoan parasites transmitted by the bite of sand fly vectors producing a wide spectrum of diseases in their mammalian hosts. These diverse clinical outcomes are directly associated with parasite strain and species diversity. Although Leishmania reproduction is mainly clonal, a cryptic sexual cycle capable of producing hybrid genotypes has been inferred from population genetic studies and directly demonstrated by laboratory crosses. Experimentally, mating competence has been largely confined to promastigotes developing in the sand fly midgut. The ability to hybridize culture promastigotes in vitro has been limited so far to low-efficiency crosses between two Leishmania tropica strains, L747 and MA37, that mate with high efficiency in flies. Here, we show that exposure of promastigote cultures to DNA damage stress produces a remarkably enhanced efficiency of in vitro hybridization of the L. tropica strains and extends to other species, including Leishmania donovani, Leishmania infantum, and Leishmania braziliensis, a capacity to generate intra- and interspecific hybrids. Whole-genome sequencing and total DNA content analyses indicate that the hybrids are in each case full genome, mostly tetraploid hybrids. Single-cell RNA sequencing of the L747 and MA37 parental lines highlights the transcriptome heterogeneity of culture promastigotes and reveals discrete clusters that emerge post-irradiation in which genes potentially involved in genetic exchange are expressed, including the ancestral gamete fusogen HAP2. By generating reporter constructs for HAP2, we could select for promastigotes that could either hybridize or not in vitro. Overall, this work reveals that there are specific populations involved in Leishmania hybridization associated with a discernible transcriptomic signature, and that stress facilitated in vitro hybridization can be a transformative approach to generate large numbers of hybrid genotypes between diverse species and strains.
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Affiliation(s)
- Isabelle Louradour
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, United States
| | - Tiago Rodrigues Ferreira
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, United States
| | - Emma Duge
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, United States
| | - Nadira Karunaweera
- Department of Parasitology, Faculty of Medicine, University of Colombo, Colombo, Sri Lanka
| | - Andrea Paun
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, United States
| | - David Sacks
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, United States
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5
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Barcaccia G, Palumbo F, Sgorbati S, Albertini E, Pupilli F. A Reappraisal of the Evolutionary and Developmental Pathway of Apomixis and Its Genetic Control in Angiosperms. Genes (Basel) 2020; 11:E859. [PMID: 32731368 PMCID: PMC7466056 DOI: 10.3390/genes11080859] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 07/24/2020] [Accepted: 07/27/2020] [Indexed: 12/16/2022] Open
Abstract
Apomixis sensu stricto (agamospermy) is asexual reproduction by seed. In angiosperms it represents an easy byway of life cycle renewal through gamete-like cells that give rise to maternal embryos without ploidy reduction (meiosis) and ploidy restitution (syngamy). The origin of apomixis still represents an unsolved problem, as it may be either evolved from sex or the other way around. This review deals with a reappraisal of the origin of apomixis in order to deepen knowledge on such asexual mode of reproduction which seems mainly lacking in the most basal angiosperm orders (i.e., Amborellales, Nymphaeales and Austrobaileyales, also known as ANA-grade), while it clearly occurs in different forms and variants in many unrelated families of monocots and eudicots. Overall findings strengthen the hypothesis that apomixis as a whole may have evolved multiple times in angiosperm evolution following different developmental pathways deviating to different extents from sexuality. Recent developments on the genetic control of apomixis in model species are also presented and adequately discussed in order to shed additional light on the antagonist theories of gain- and loss-of-function over sexuality.
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Affiliation(s)
- Gianni Barcaccia
- Department of Agronomy Food Natural Resources Animals Environment, University of Padova, Campus of Agripolis, Viale dell’Università 16, Legnaro, 35020 Padova, Italy;
| | - Fabio Palumbo
- Department of Agronomy Food Natural Resources Animals Environment, University of Padova, Campus of Agripolis, Viale dell’Università 16, Legnaro, 35020 Padova, Italy;
| | - Sergio Sgorbati
- Department of Environmental and Territory Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milano, Italy;
| | - Emidio Albertini
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, 06121 Perugia, Italy;
| | - Fulvio Pupilli
- Research Division of Perugia, Institute of Biosciences and Bioresources, National Research Council (CNR), Via Madonna Alta 130, 06128 Perugia, Italy;
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6
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Wu H, Yan Y, Feng J, Zhang J, Deng S, Cai X, Huang L, Xie X, Shi Q, Tan S. Cetylpyridinium bromide/montmorillonite-graphene oxide composite with good antibacterial activity. Biomed Mater 2020; 15:055002. [PMID: 32217814 DOI: 10.1088/1748-605x/ab8440] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
In this study, a cetylpyridinium bromide (CPB)/montmorillonite-graphene oxide (GM) composite (GM-CPB) was prepared by loading CPB in a carrier of GM. The chemical structure, elemental composition, morphology, thermogravimetric analysis, antibacterial activity, sustained release property and cytotoxicity were analyzed. The loading rate of CPB in a GM carrier was higher than that of the graphene oxide (GO) carrier under the same loading condition. The antibacterial activity and sustained release performance of GM-CPB were also better than that of GO-CPB; furthermore, GM-CPB showed lower cytotoxicity than CPB.
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Affiliation(s)
- Haoping Wu
- State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou 510070, People's Republic of China. Guangdong Engineering & Technology Research Centre of Graphene-Like Materials and Products, Department of Chemistry, College of Chemistry and Materials Science, Jinan University, Guangzhou 510632, People's Republic of China. These authors contributed equally
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7
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Ligthart K, Belzer C, de Vos WM, Tytgat HLP. Bridging Bacteria and the Gut: Functional Aspects of Type IV Pili. Trends Microbiol 2020; 28:340-348. [PMID: 32298612 DOI: 10.1016/j.tim.2020.02.003] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 01/31/2020] [Accepted: 02/10/2020] [Indexed: 12/14/2022]
Abstract
Cell-surface-located proteinaceous appendages, such as flagella and fimbriae or pili, are ubiquitous in bacterial communities. Here, we focus on conserved type IV pili (T4P) produced by bacteria in the intestinal tract, one of the most densely populated human ecosystems. Computational analysis revealed that approximately 30% of known intestinal bacteria are predicted to produce T4P. To rationalize how T4P allow intestinal bacteria to interact with their environment, other microbiota members, and host cells, we review their established role in gut commensals and pathogens with respect to adherence, motility, and biofilm formation, as well as protein secretion and DNA uptake. This work indicates that T4P are widely spread among the known members of the intestinal microbiota and that their contribution to human health might be underestimated.
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Affiliation(s)
- Kate Ligthart
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
| | - Clara Belzer
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands
| | - Willem M de Vos
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands; Research Program Human Microbiome, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Hanne L P Tytgat
- Laboratory of Microbiology, Wageningen University, Wageningen, The Netherlands.
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8
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Forsdyke DR. When acting as a reproductive barrier for sympatric speciation, hybrid sterility can only be primary. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz135] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractAnimal gametes unite to form a zygote that develops into an adult with gonads that, in turn, produce gametes. Interruption of this germinal cycle by prezygotic or postzygotic reproductive barriers can result in two cycles, each with the potential to evolve into a new species. When the speciation process is complete, members of each species are fully reproductively isolated from those of the other. During speciation a primary barrier may be supported and eventually superceded by a later-appearing secondary barrier. For those holding certain cases of prezygotic isolation to be primary (e.g. elephant cannot copulate with mouse), the onus is to show that they had not been preceded over evolutionary time by periods of postzygotic hybrid inviability (genically determined) or sterility (genically or chromosomally determined). Likewise, the onus is upon those holding cases of hybrid inviability to be primary (e.g. Dobzhansky–Muller epistatic incompatibilities) to show that they had not been preceded by periods, however brief, of hybrid sterility. The latter, when acting as a sympatric barrier causing reproductive isolation, can only be primary. In many cases, hybrid sterility may result from incompatibilities between parental chromosomes that attempt to pair during meiosis in the gonad of their offspring (Winge-Crowther-Bateson incompatibilities). While such incompatibilities have long been observed on a microscopic scale, there is growing evidence for a role of dispersed finer DNA sequence differences (i.e. in base k-mers).
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Affiliation(s)
- Donald R Forsdyke
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON K7L3N6, Canada
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9
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Forsdyke DR. Success of alignment-free oligonucleotide (k-mer) analysis confirms relative importance of genomes not genes in speciation and phylogeny. Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/blz096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
AbstractThe utility of DNA sequence substrings (k-mers) in alignment-free phylogenetic classification, including that of bacteria and viruses, is increasingly recognized. However, its biological basis eludes many 21st century practitioners. A path from the 19th century recognition of the informational basis of heredity to the modern era can be discerned. Crick’s DNA ‘unpairing postulate’ predicted that recombinational pairing of homologous DNAs during meiosis would be mediated by short k-mers in the loops of stem-loop structures extruded from classical duplex helices. The complementary ‘kissing’ duplex loops – like tRNA anticodon–codon k-mer duplexes – would seed a more extensive pairing that would then extend until limited by lack of homology or other factors. Indeed, this became the principle behind alignment-based methods that assessed similarity by degree of DNA–DNA reassociation in vitro. These are now seen as less sensitive than alignment-free methods that are closely consistent, both theoretically and mechanistically, with chromosomal anti-recombination models for the initiation of divergence into new species. The analytical power of k-mer differences supports the theses that evolutionary advance sometimes serves the needs of nucleic acids (genomes) rather than proteins (genes), and that such differences can play a role in early speciation events.
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Affiliation(s)
- Donald R Forsdyke
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
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10
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Dong X, Song J, Chen J, Bi D, Wang W, Ren Y, Wang H, Wang G, Tang KFJ, Wang X, Huang J. Conjugative Transfer of the pVA1-Type Plasmid Carrying the pirAB vp Genes Results in the Formation of New AHPND-Causing Vibrio. Front Cell Infect Microbiol 2019; 9:195. [PMID: 31231618 PMCID: PMC6568040 DOI: 10.3389/fcimb.2019.00195] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 05/21/2019] [Indexed: 11/27/2022] Open
Abstract
Acute hepatopancreatic necrosis disease (AHPND) has caused sharp declines in aquaculture industries of whiteleg shrimp Penaeus vannamei in Asia and the Americas since 2010. Vibrio parahaemolyticus, V. campbellii, V. owensii, and V. punensis have been proved to cause AHPND. However, the mechanisms underlying the burgeoning number of Vibrio species that cause AHPND is not known. All of AHPND-causing Vibrio bacteria (VAHPND) harbor a highly homologous plasmid (designated as pVA1-type) carrying pirABvp toxin genes. In this study, we demonstrate conclusively that the pVA1-type plasmid can be transferred from VAHPND to non-pathogenic bacteria. We constructed a pVPGX1-Cmr plasmid (a pVA1-type plasmid) by adding a chloramphenicol resistance gene as a marker in a donor AHPND-causing V. parahaemolyticus 20130629002S01 (Vp2S01). Horizontal transfer of this plasmid was successfully performed from the AHPND-Vp2S01 to a non-pathogenic strain of V. campbellii at the transfer efficiency of 2.6×10−8 transconjugant/recipient, and DNase I treatment did not eliminate the transfer. The recipient V. campbellii acquired the pVA1-type plasmid and was shown to produce pirABvp RNA and proteins. Challenge studies using the transconjugant caused 100% mortality in exposed groups of P. vannamei. The challenged shrimp, infected with the transconjugant bacteria, showed typical gross signs and histological lesions of AHPND. These results demonstrated the conjugative transfer of an AHPND pVA1-type plasmid. It provides timely information for explaining the increased species of AHPND-causing Vibrio bacteria and will be useful in the development of management strategies leading to the prevention and control of AHPND.
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Affiliation(s)
- Xuan Dong
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Laboratory for Marine Fisheries Science and Food Production Processes, National Laboratory for Marine Science and Technology (Qingdao), Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Qingdao, China
| | - Jipeng Song
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Laboratory for Marine Fisheries Science and Food Production Processes, National Laboratory for Marine Science and Technology (Qingdao), Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Qingdao, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, China
| | - Jiayuan Chen
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Laboratory for Marine Fisheries Science and Food Production Processes, National Laboratory for Marine Science and Technology (Qingdao), Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Qingdao, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, China
| | - Dexi Bi
- Department of Pathology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China
| | - Wenchao Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Laboratory for Marine Fisheries Science and Food Production Processes, National Laboratory for Marine Science and Technology (Qingdao), Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Qingdao, China
| | - Yanbei Ren
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Laboratory for Marine Fisheries Science and Food Production Processes, National Laboratory for Marine Science and Technology (Qingdao), Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Qingdao, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, China
| | - Hailiang Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Laboratory for Marine Fisheries Science and Food Production Processes, National Laboratory for Marine Science and Technology (Qingdao), Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Qingdao, China
| | - Guohao Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Laboratory for Marine Fisheries Science and Food Production Processes, National Laboratory for Marine Science and Technology (Qingdao), Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Qingdao, China
| | - Kathy F J Tang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Laboratory for Marine Fisheries Science and Food Production Processes, National Laboratory for Marine Science and Technology (Qingdao), Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Qingdao, China
| | - Xuepeng Wang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Laboratory for Marine Fisheries Science and Food Production Processes, National Laboratory for Marine Science and Technology (Qingdao), Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Qingdao, China.,Shandong Provincial Key Laboratory of Animal Biotechnology and Disease Control and Prevention, Shandong Agricultural University, Tai'an, China
| | - Jie Huang
- Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Laboratory for Marine Fisheries Science and Food Production Processes, National Laboratory for Marine Science and Technology (Qingdao), Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Qingdao, China
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11
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Albertini E, Barcaccia G, Carman JG, Pupilli F. Did apomixis evolve from sex or was it the other way around? JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2951-2964. [PMID: 30854543 DOI: 10.1093/jxb/erz109] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 02/25/2019] [Indexed: 05/20/2023]
Abstract
In angiosperms, there are two pathways of reproduction through seeds: sexual, or amphimictic, and asexual, or apomictic. The essential feature of apomixis is that an embryo in an ovule is formed autonomously. It may form from a cell of the nucellus or integuments in an otherwise sexual ovule, a process referred to as adventitious embryony. Alternatively, the embryo may form by parthenogenesis from an unreduced egg that forms in an unreduced embryo sac. The latter may form from an ameiotic megasporocyte, in which case it is referred to as diplospory, or from a cell of the nucellus or integument, in which case it is referred to as apospory. Progeny of apomictic plants are generally identical to the mother plant. Apomixis has been seen over the years as either a gain- or loss-of-function over sexuality, implying that the latter is the default condition. Here, we consider an additional point of view, that apomixis may be anciently polyphenic with sex and that both reproductive phenisms involve anciently canalized components of complex molecular processes. This polyphenism viewpoint suggests that apomixis fails to occur in obligately sexual eukaryotes because genetic or epigenetic modifications have silenced the primitive sex apomixis switch and/or disrupted molecular capacities for apomixis. In eukaryotes where sex and apomixis are clearly polyphenic, apomixis exponentially drives clonal fecundity during reproductively favorable conditions, while stress induces sex for stress-tolerant spore or egg formation. The latter often guarantees species survival during environmentally harsh seasons.
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Affiliation(s)
- Emidio Albertini
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Perugia, Italy
| | - Gianni Barcaccia
- Laboratory of Genomics, Department of Agronomy, Food, Natural Resources, Animals and the Environment (DAFNAE), University of Padova Legnaro, PD, Italy
| | - John G Carman
- Department of Plants, Soils and Climate, Utah State University, Logan, Utah, USA
| | - Fulvio Pupilli
- Institute of Biosciences and Bioresources, Research Division of Perugia, National Research Council (CNR), Perugia, Italy
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12
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Hörandl E, Speijer D. How oxygen gave rise to eukaryotic sex. Proc Biol Sci 2019; 285:rspb.2017.2706. [PMID: 29436502 PMCID: PMC5829205 DOI: 10.1098/rspb.2017.2706] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 01/15/2018] [Indexed: 12/13/2022] Open
Abstract
How did full meiotic eukaryotic sex evolve and what was the immediate advantage allowing it to develop? We propose that the crucial determinant can be found in internal reactive oxygen species (ROS) formation at the start of eukaryotic evolution approximately 2 × 109 years ago. The large amount of ROS coming from a bacterial endosymbiont gave rise to DNA damage and vast increases in host genome mutation rates. Eukaryogenesis and chromosome evolution represent adaptations to oxidative stress. The host, an archaeon, most probably already had repair mechanisms based on DNA pairing and recombination, and possibly some kind of primitive cell fusion mechanism. The detrimental effects of internal ROS formation on host genome integrity set the stage allowing evolution of meiotic sex from these humble beginnings. Basic meiotic mechanisms thus probably evolved in response to endogenous ROS production by the ‘pre-mitochondrion’. This alternative to mitosis is crucial under novel, ROS-producing stress situations, like extensive motility or phagotrophy in heterotrophs and endosymbiontic photosynthesis in autotrophs. In multicellular eukaryotes with a germline–soma differentiation, meiotic sex with diploid–haploid cycles improved efficient purging of deleterious mutations. Constant pressure of endogenous ROS explains the ubiquitous maintenance of meiotic sex in practically all eukaryotic kingdoms. Here, we discuss the relevant observations underpinning this model.
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Affiliation(s)
- Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants, University of Goettingen, Göttingen, Germany
| | - Dave Speijer
- Department of Medical Biochemistry, Academic Medical Centre (AMC), University of Amsterdam, Amsterdam, The Netherlands
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Mhlwatika Z, Aderibigbe BA. Application of Dendrimers for the Treatment of Infectious Diseases. Molecules 2018; 23:E2205. [PMID: 30200314 PMCID: PMC6225509 DOI: 10.3390/molecules23092205] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 06/14/2018] [Accepted: 06/15/2018] [Indexed: 01/14/2023] Open
Abstract
Dendrimers are drug delivery systems that are characterized by a three-dimensional, star-shaped, branched macromolecular network. They possess ideal properties such as low polydispersity index, biocompatibility and good water solubility. They are made up of the interior and the exterior layers. The exterior layer consists of functional groups that are useful for conjugation of drugs and targeting moieties. The interior layer exhibits improved drug encapsulation efficiency, reduced drug toxicity, and controlled release mechanisms. These unique properties make them useful for drug delivery. Dendrimers have attracted considerable attention as drug delivery system for the treatment of infectious diseases. The treatment of infectious diseases is hampered severely by drug resistance. Several properties of dendrimers such as their ability to overcome drug resistance, toxicity and control the release mechanism of the encapsulated drugs make them ideal systems for the treatment of infectious disease. The aim of this review is to discuss the potentials of dendrimers for the treatment of viral and parasitic infections.
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Affiliation(s)
- Zandile Mhlwatika
- Department of Chemistry, University of Fort Hare, Alice Campus, Eastern Cape 5700, South Africa.
| | - Blessing Atim Aderibigbe
- Department of Chemistry, University of Fort Hare, Alice Campus, Eastern Cape 5700, South Africa.
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Forsdyke DR. The chromosomal basis of species initiation: Prdm9 as an anti-speciation gene. Biol J Linn Soc Lond 2018. [DOI: 10.1093/biolinnean/bly035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Donald R Forsdyke
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON, Canada
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