1
|
Chen BC, Chen YZ, Lin HY. An Introduced RNA-Only Approach for Plasmid Curing via the CRISPR-Cpf1 System in Saccharomyces cerevisiae. Biomolecules 2023; 13:1561. [PMID: 37892243 PMCID: PMC10604987 DOI: 10.3390/biom13101561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/13/2023] [Accepted: 10/19/2023] [Indexed: 10/29/2023] Open
Abstract
The CRISPR-Cas system has been widely used for genome editing due to its convenience, simplicity and flexibility. Using a plasmid-carrying Cas protein and crRNA or sgRNA expression cassettes is an efficient strategy in the CRISPR-Cas genome editing system. However, the plasmid remains in the cells after genome editing. Development of general plasmid-curing strategies is necessary. Based on our previous CRISPR-Cpf1 genome-editing system in Saccharomyces cerevisiae, the crRNA, designed for the replication origin of the CRISPR-Cpf1 plasmid, and the ssDNA, as a template for homologous recombination, were introduced for plasmid curing. The efficiency of the plasmid curing was 96 ± 4%. In addition, we further simplified the plasmid curing system by transforming only one crRNA into S. cerevisiae, and the curing efficiency was about 70%. In summary, we have developed a CRISPR-mediated plasmid-curing system. The RNA-only plasmid curing system is fast and easy. This plasmid curing strategy can be applied in broad hosts by designing crRNA specific for the replication origin of the plasmid. The plasmid curing system via CRISPR-Cas editing technology can be applied to produce traceless products without foreign genes and to perform iterative processes in multiple rounds of genome editing.
Collapse
Affiliation(s)
- Bo-Chou Chen
- Bioresource Collection and Research Center, Food Industry Research and Development Institute, Hsinchu 300, Taiwan;
| | - Yu-Zhen Chen
- Department of Food Science and Technology, Hungkuang University, Taichung 433, Taiwan;
| | - Huan-Yu Lin
- Bioresource Collection and Research Center, Food Industry Research and Development Institute, Hsinchu 300, Taiwan;
| |
Collapse
|
2
|
Mendoza-Hoffmann F, Yang L, Buratto D, Brito-Sánchez J, Garduño-Javier G, Salinas-López E, Uribe-Álvarez C, Ortega R, Sotelo-Serrano O, Cevallos MÁ, Ramírez-Silva L, Uribe-Carvajal S, Pérez-Hernández G, Celis-Sandoval H, García-Trejo JJ. Inhibitory to non-inhibitory evolution of the ζ subunit of the F 1F O-ATPase of Paracoccus denitrificans and α-proteobacteria as related to mitochondrial endosymbiosis. Front Mol Biosci 2023; 10:1184200. [PMID: 37664184 PMCID: PMC10469736 DOI: 10.3389/fmolb.2023.1184200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 08/01/2023] [Indexed: 09/05/2023] Open
Abstract
Introduction: The ζ subunit is a potent inhibitor of the F1FO-ATPase of Paracoccus denitrificans (PdF1FO-ATPase) and related α-proteobacteria different from the other two canonical inhibitors of bacterial (ε) and mitochondrial (IF1) F1FO-ATPases. ζ mimics mitochondrial IF1 in its inhibitory N-terminus, blocking the PdF1FO-ATPase activity as a unidirectional pawl-ratchet and allowing the PdF1FO-ATP synthase turnover. ζ is essential for the respiratory growth of P. denitrificans, as we showed by a Δζ knockout. Given the vital role of ζ in the physiology of P. denitrificans, here, we assessed the evolution of ζ across the α-proteobacteria class. Methods: Through bioinformatic, biochemical, molecular biology, functional, and structural analyses of several ζ subunits, we confirmed the conservation of the inhibitory N-terminus of ζ and its divergence toward its C-terminus. We reconstituted homologously or heterologously the recombinant ζ subunits from several α-proteobacteria into the respective F-ATPases, including free-living photosynthetic, facultative symbiont, and intracellular facultative or obligate parasitic α-proteobacteria. Results and discussion: The results show that ζ evolved, preserving its inhibitory function in free-living α-proteobacteria exposed to broad environmental changes that could compromise the cellular ATP pools. However, the ζ inhibitory function was diminished or lost in some symbiotic α-proteobacteria where ζ is non-essential given the possible exchange of nutrients and ATP from hosts. Accordingly, the ζ gene is absent in some strictly parasitic pathogenic Rickettsiales, which may obtain ATP from the parasitized hosts. We also resolved the NMR structure of the ζ subunit of Sinorhizobium meliloti (Sm-ζ) and compared it with its structure modeled in AlphaFold. We found a transition from a compact ordered non-inhibitory conformation into an extended α-helical inhibitory N-terminus conformation, thus explaining why the Sm-ζ cannot exert homologous inhibition. However, it is still able to inhibit the PdF1FO-ATPase heterologously. Together with the loss of the inhibitory function of α-proteobacterial ε, the data confirm that the primary inhibitory function of the α-proteobacterial F1FO-ATPase was transferred from ε to ζ and that ζ, ε, and IF1 evolved by convergent evolution. Some key evolutionary implications on the endosymbiotic origin of mitochondria, as most likely derived from α-proteobacteria, are also discussed.
Collapse
Affiliation(s)
- Francisco Mendoza-Hoffmann
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de México, México
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Lingyun Yang
- iHuman Institute, ShanghaiTech University, Shanghai, China
| | - Damiano Buratto
- Shanghai Institute for Advanced Immunochemical Studies, ShanghaiTech University, Shanghai, China
| | - Jorge Brito-Sánchez
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de México, México
| | - Gilberto Garduño-Javier
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de México, México
| | - Emiliano Salinas-López
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de México, México
| | - Cristina Uribe-Álvarez
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de México, México
| | - Raquel Ortega
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de México, México
| | - Oliver Sotelo-Serrano
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de México, México
| | - Miguel Ángel Cevallos
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de México, México
| | - Leticia Ramírez-Silva
- Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de México, México
| | - Salvador Uribe-Carvajal
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de México, México
| | - Gerardo Pérez-Hernández
- Departamento de Ciencias Naturales, Universidad Autónoma Metropolitana, Unidad Cuajimalpa, Ciudad de México, México
| | - Heliodoro Celis-Sandoval
- Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de México, México
| | - José J. García-Trejo
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de México, México
| |
Collapse
|
3
|
Mendoza-Hoffmann F, Zarco-Zavala M, Ortega R, Celis-Sandoval H, Torres-Larios A, García-Trejo JJ. Evolution of the Inhibitory and Non-Inhibitory ε, ζ, and IF 1 Subunits of the F 1F O-ATPase as Related to the Endosymbiotic Origin of Mitochondria. Microorganisms 2022; 10:microorganisms10071372. [PMID: 35889091 PMCID: PMC9317440 DOI: 10.3390/microorganisms10071372] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 07/03/2022] [Accepted: 07/03/2022] [Indexed: 12/10/2022] Open
Abstract
The F1FO-ATP synthase nanomotor synthesizes >90% of the cellular ATP of almost all living beings by rotating in the “forward” direction, but it can also consume the same ATP pools by rotating in “reverse.” To prevent futile F1FO-ATPase activity, several different inhibitory proteins or domains in bacteria (ε and ζ subunits), mitochondria (IF1), and chloroplasts (ε and γ disulfide) emerged to block the F1FO-ATPase activity selectively. In this study, we analyze how these F1FO-ATPase inhibitory proteins have evolved. The phylogeny of the α-proteobacterial ε showed that it diverged in its C-terminal side, thus losing both the inhibitory function and the ATP-binding/sensor motif that controls this inhibition. The losses of inhibitory function and the ATP-binding site correlate with an evolutionary divergence of non-inhibitory α-proteobacterial ε and mitochondrial δ subunits from inhibitory bacterial and chloroplastidic ε subunits. Here, we confirm the lack of inhibitory function of wild-type and C-terminal truncated ε subunits of P. denitrificans. Taken together, the data show that ζ evolved to replace ε as the primary inhibitor of the F1FO-ATPase of free-living α-proteobacteria. However, the ζ inhibitory function was also partially lost in some symbiotic α-proteobacteria and totally lost in some strictly parasitic α-proteobacteria such as the Rickettsiales order. Finally, we found that ζ and IF1 likely evolved independently via convergent evolution before and after the endosymbiotic origin mitochondria, respectively. This led us to propose the ε and ζ subunits as tracer genes of the pre-endosymbiont that evolved into the actual mitochondria.
Collapse
Affiliation(s)
- Francisco Mendoza-Hoffmann
- Facultad de Ciencias Químicas e Ingeniería, Universidad Autónoma de Baja California (UABC)—Campus Tijuana, Tijuana C.P. 22390, Baja California, Mexico
- Correspondence: (F.M.-H.); (J.J.G.-T.)
| | - Mariel Zarco-Zavala
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de Mexico C.P. 04510, Coyoacan, Mexico
| | - Raquel Ortega
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de Mexico C.P. 04510, Coyoacan, Mexico
| | - Heliodoro Celis-Sandoval
- Instituto de Fisiología Celular (IFC), Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de Mexico C.P. 04510, Coyoacan, Mexico
| | - Alfredo Torres-Larios
- Instituto de Fisiología Celular (IFC), Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de Mexico C.P. 04510, Coyoacan, Mexico
| | - José J. García-Trejo
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Ciudad de Mexico C.P. 04510, Coyoacan, Mexico
- Correspondence: (F.M.-H.); (J.J.G.-T.)
| |
Collapse
|
4
|
Heydari S, Malekzadeh R, Jazayeri MH, Sarrafnejad A, Siavoshi F. Detection of peptidoglycan in yeast as a marker for the presence or abundance of intracellular Helicobacter pylori and Staphylococcus. Arch Microbiol 2022; 204:407. [PMID: 35726098 DOI: 10.1007/s00203-022-03045-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 05/21/2022] [Accepted: 05/27/2022] [Indexed: 11/26/2022]
Abstract
Peptidoglycan (PG) was targeted as the marker for bacterial occurrence inside yeast. Detection of only few bacteria in old and new generations of yeast raised the question of how yeast controls the abundance of its intracellular bacteria. One gastric C. tropicalis that showed concurrence of H. pylori and Staphylococcus 16S rDNA was stained for assessing the viability of intracellular bacteria. Fluorescein isothiocyanate (FITC)-labeled anti-PG monoclonal antibody (APGMAb) was used for detection of PG inside yeast by direct immunofluorescence. APGMAb-coated magnetic beads were used for separation of bacteria from disrupted yeasts. Bead-bound bacteria were separated, fixed, stained, and examined by scanning electron microscope (SEM). Bead-bound bacteria were cultured and identified by amplification and sequencing of 16S rDNA. Fluorescence microscopy demonstrated occurrence of few live bacteria inside yeast cells. FITC- APGMAb interacted with PG of intracellular bacteria, appearing as few green spots in mother and daughter yeast cells. Interestingly, PG fragments were also detected in the exterior of yeast cells. SEM observations showed separated bead-bound bacilli and cocci. Culture of Staphylococcus was positive. Sequencing results confirmed identity of separated bacteria as H. pylori and Staphylococcus. PG detected inside yeast may have belonged to H. pylori, Staphylococcus or any other intracellular bacteria that coexisted in yeast as its microbiome. Detection of only few intracellular bacteria in old and new generations of yeast as well as PG fragments in their exterior suggested that yeast controls the abundance of its intracellular bacteria at low rate by hydrolysis and exporting of PG.
Collapse
Affiliation(s)
- Samira Heydari
- Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran, Iran
| | - Reza Malekzadeh
- Digestive Disease Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mir Hadi Jazayeri
- Immunology Research Center, Iran University of Medical Sciences, Tehran, Iran
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Abdolfattah Sarrafnejad
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
| | - Farideh Siavoshi
- Department of Microbiology, School of Biology, University College of Sciences, University of Tehran, Tehran, Iran.
| |
Collapse
|
5
|
Ishaqat A, Herrmann A. Polymers Strive for Accuracy: From Sequence-Defined Polymers to mRNA Vaccines against COVID-19 and Polymers in Nucleic Acid Therapeutics. J Am Chem Soc 2021; 143:20529-20545. [PMID: 34841867 DOI: 10.1021/jacs.1c08484] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Unquestionably, polymers have influenced the world over the past 100 years. They are now more crucial than ever since the COVID-19 pandemic outbreak. The pandemic paved the way for certain polymers to be in the spotlight, namely sequence-defined polymers such as messenger ribonucleic acid (mRNA), which was the first type of vaccine to be authorized in the U.S. and Europe to protect against the SARS-CoV-2 virus. This rise of mRNA will probably influence scientific research concerning nucleic acids in general and RNA therapeutics in specific. In this Perspective, we highlight the recent trends in sequence-controlled and sequence-defined polymers. Then we discuss mRNA vaccines as an example to illustrate the need of ultimate sequence control to achieve complex functions such as specific activation of the immune system. We briefly present how mRNA vaccines are produced, the importance of modified nucleotides, the characteristic features, and the advantages and challenges associated with this class of vaccines. Finally, we discuss the chances and opportunities for polymer chemistry to provide solutions and contribute to the future progress of RNA-based therapeutics. We highlight two particular roles of polymers in this context. One represents conjugation of polymers to nucleic acids to form biohybrids. The other is concerned with advanced polymer-based carrier systems for nucleic acids. We believe that polymers can help to address present problems of RNA-based therapeutic technologies and impact the field beyond the COVID-19 pandemic.
Collapse
Affiliation(s)
- Aman Ishaqat
- DWI - Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, 52074 Aachen, Germany.,Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany
| | - Andreas Herrmann
- DWI - Leibniz Institute for Interactive Materials, Forckenbeckstraße 50, 52074 Aachen, Germany.,Institute of Technical and Macromolecular Chemistry, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany
| |
Collapse
|
6
|
The 3 × 120° rotary mechanism of Paracoccus denitrificans F 1-ATPase is different from that of the bacterial and mitochondrial F 1-ATPases. Proc Natl Acad Sci U S A 2020; 117:29647-29657. [PMID: 33168750 PMCID: PMC7703542 DOI: 10.1073/pnas.2003163117] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The rotation of Paracoccus denitrificans F1-ATPase (PdF1) was studied using single-molecule microscopy. At all concentrations of adenosine triphosphate (ATP) or a slowly hydrolyzable ATP analog (ATPγS), above or below K m, PdF1 showed three dwells per turn, each separated by 120°. Analysis of dwell time between steps showed that PdF1 executes binding, hydrolysis, and probably product release at the same dwell. The comparison of ATP binding and catalytic pauses in single PdF1 molecules suggested that PdF1 executes both elementary events at the same rotary position. This point was confirmed in an inhibition experiment with a nonhydrolyzable ATP analog (AMP-PNP). Rotation assays in the presence of adenosine diphosphate (ADP) or inorganic phosphate at physiological concentrations did not reveal any obvious substeps. Although the possibility of the existence of substeps remains, all of the datasets show that PdF1 is principally a three-stepping motor similar to bacterial vacuolar (V1)-ATPase from Thermus thermophilus This contrasts with all other known F1-ATPases that show six or nine dwells per turn, conducting ATP binding and hydrolysis at different dwells. Pauses by persistent Mg-ADP inhibition or the inhibitory ζ-subunit were also found at the same angular position of the rotation dwell, supporting the simplified chemomechanical scheme of PdF1 Comprehensive analysis of rotary catalysis of F1 from different species, including PdF1, suggests a clear trend in the correlation between the numbers of rotary steps of F1 and Fo domains of F-ATP synthase. F1 motors with more distinctive steps are coupled with proton-conducting Fo rings with fewer proteolipid subunits, giving insight into the design principle the F1Fo of ATP synthase.
Collapse
|
7
|
Brown JA, Sammy MJ, Ballinger SW. An evolutionary, or "Mitocentric" perspective on cellular function and disease. Redox Biol 2020; 36:101568. [PMID: 32512469 PMCID: PMC7281786 DOI: 10.1016/j.redox.2020.101568] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 05/01/2020] [Accepted: 05/05/2020] [Indexed: 12/11/2022] Open
Abstract
The incidence of common, metabolic diseases (e.g. obesity, cardiovascular disease, diabetes) with complex genetic etiology has been steadily increasing nationally and globally. While identification of a genetic model that explains susceptibility and risk for these diseases has been pursued over several decades, no clear paradigm has yet been found to disentangle the genetic basis of polygenic/complex disease development. Since the evolution of the eukaryotic cell involved a symbiotic interaction between the antecedents of the mitochondrion and nucleus (which itself is a genetic hybrid), we suggest that this history provides a rational basis for investigating whether genetic interaction and co-evolution of these genomes still exists. We propose that both mitochondrial and Mendelian, or "mito-Mendelian" genetics play a significant role in cell function, and thus disease risk. This paradigm contemplates the natural variation and co-evolution of both mitochondrial and nuclear DNA backgrounds on multiple mitochondrial functions that are discussed herein, including energy production, cell signaling and immune response, which collectively can influence disease development. At the nexus of these processes is the economy of mitochondrial metabolism, programmed by both mitochondrial and nuclear genomes.
Collapse
Affiliation(s)
- Jamelle A Brown
- Department of Pathology, Division of Molecular and Cellular Pathology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Melissa J Sammy
- Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - Scott W Ballinger
- Department of Pathology, Division of Molecular and Cellular Pathology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
| |
Collapse
|
8
|
Constitutive release of CPS1 in bile and its role as a protective cytokine during acute liver injury. Proc Natl Acad Sci U S A 2019; 116:9125-9134. [PMID: 30979808 DOI: 10.1073/pnas.1822173116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Carbamoyl phosphate synthetase-1 (CPS1) is the major mitochondrial urea cycle enzyme in hepatocytes. It is released into mouse and human blood during acute liver injury, where is has a short half-life. The function of CPS1 in blood and the reason for its short half-life in serum are unknown. We show that CPS1 is released normally into mouse and human bile, and pathologically into blood during acute liver injury. Other cytoplasmic and mitochondrial urea cycle enzymes are also found in normal mouse bile. Serum, bile, and purified CPS1 manifest sedimentation properties that overlap with extracellular vesicles, due to the propensity of CPS1 to aggregate despite being released primarily as a soluble protein. During liver injury, CPS1 in blood is rapidly sequestered by monocytes, leading to monocyte M2-polarization and homing to the liver independent of its enzyme activity. Recombinant CPS1 (rCPS1), but not control r-transferrin, increases hepatic macrophage numbers and phagocytic activity. Notably, rCPS1 does not activate hepatic macrophages directly; rather, it activates bone marrow and circulating monocytes that then home to the liver. rCPS1 administration prevents mouse liver damage induced by Fas ligand or acetaminophen, but this protection is absent in macrophage-deficient mice. Moreover, rCPS1 protects from acetaminophen-induced liver injury even when given therapeutically after injury induction. In summary, CPS1 is normally found in bile but is released by hepatocytes into blood upon liver damage. We demonstrate a nonenzymatic function of CPS1 as an antiinflammatory protective cytokine during acute liver injury.
Collapse
|
9
|
Bennett JP. Medical hypothesis: Neurodegenerative diseases arise from oxidative damage to electron tunneling proteins in mitochondria. Med Hypotheses 2019; 127:1-4. [PMID: 31088629 DOI: 10.1016/j.mehy.2019.03.034] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 12/15/2022]
Abstract
Mitochondria likely arose from serial endosymbiosis by early eukaryotic cells and control electron flow to molecular oxygen to facilitate energy transformation. Mitochondria translate between the quantum and macroscopic worlds and utilize quantum tunneling of electrons to reduce activation energy barriers to electron flow. Electron tunneling has been extensively characterized in Complex I of the electron transport chain. Age-related increases in oxidative damage to these electron tunneling systems may account for decreased energy storage found in aged and neurodegenerative disease tissues, such as those from sufferers of amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD) and Parkinson's disease (PD). This hypothesis is testable. If correct, this hypothesis supports pre-symptomatic, mitochondrially-directed oxygen free radical scavenging therapies.
Collapse
Affiliation(s)
- James P Bennett
- Neurodegeneration Therapeutics, Inc., 3050A Berkmar Drive, Charlottesville, VA 22901-3450, United States.
| |
Collapse
|
10
|
Salvucci E. The human-microbiome superorganism and its modulation to restore health. Int J Food Sci Nutr 2019; 70:781-795. [DOI: 10.1080/09637486.2019.1580682] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- E. Salvucci
- Instituto de Ciencia y Tecnología de Alimentos Córdoba (ICYTAC-CONICET-UNC), Córdoba, Argentina
- Facultad de Ciencias Exactas, Físicas y Naturales; Facultad de Ciencias Agropecuarias, Universidad Nacional de Córdoba, Córdoba
| |
Collapse
|
11
|
Nora LC, Westmann CA, Martins‐Santana L, Alves LDF, Monteiro LMO, Guazzaroni M, Silva‐Rocha R. The art of vector engineering: towards the construction of next-generation genetic tools. Microb Biotechnol 2019; 12:125-147. [PMID: 30259693 PMCID: PMC6302727 DOI: 10.1111/1751-7915.13318] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 08/29/2018] [Accepted: 08/31/2018] [Indexed: 12/20/2022] Open
Abstract
When recombinant DNA technology was developed more than 40 years ago, no one could have imagined the impact it would have on both society and the scientific community. In the field of genetic engineering, the most important tool developed was the plasmid vector. This technology has been continuously expanding and undergoing adaptations. Here, we provide a detailed view following the evolution of vectors built throughout the years destined to study microorganisms and their peculiarities, including those whose genomes can only be revealed through metagenomics. We remark how synthetic biology became a turning point in designing these genetic tools to create meaningful innovations. We have placed special focus on the tools for engineering bacteria and fungi (both yeast and filamentous fungi) and those available to construct metagenomic libraries. Based on this overview, future goals would include the development of modular vectors bearing standardized parts and orthogonally designed circuits, a task not fully addressed thus far. Finally, we present some challenges that should be overcome to enable the next generation of vector design and ways to address it.
Collapse
Affiliation(s)
- Luísa Czamanski Nora
- Ribeirão Preto Medical SchoolUniversity of São PauloRibeirão Preto, São Paulo14049‐900Brazil
| | - Cauã Antunes Westmann
- Ribeirão Preto Medical SchoolUniversity of São PauloRibeirão Preto, São Paulo14049‐900Brazil
| | | | - Luana de Fátima Alves
- Ribeirão Preto Medical SchoolUniversity of São PauloRibeirão Preto, São Paulo14049‐900Brazil
- School of Philosophy, Science and Letters of Ribeirão PretoUniversity of São PauloRibeirão Preto, São Paulo14049‐900Brazil
| | | | - María‐Eugenia Guazzaroni
- School of Philosophy, Science and Letters of Ribeirão PretoUniversity of São PauloRibeirão Preto, São Paulo14049‐900Brazil
| | - Rafael Silva‐Rocha
- Ribeirão Preto Medical SchoolUniversity of São PauloRibeirão Preto, São Paulo14049‐900Brazil
| |
Collapse
|
12
|
Oxygen therapy of the newborn from molecular understanding to clinical practice. Pediatr Res 2019; 85:20-29. [PMID: 30297877 DOI: 10.1038/s41390-018-0176-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 08/21/2018] [Accepted: 08/23/2018] [Indexed: 01/30/2023]
Abstract
Oxygen is one of the most critical components of life. Nature has taken billions of years to develop optimal atmospheric oxygen concentrations for human life, evolving from very low, peaking at 30% before reaching 20.95%. There is now increased understanding of the potential toxicity of both too much and too little oxygen, especially for preterm and asphyxiated infants and of the potential and lifelong impact of oxygen exposure, even for a few minutes after birth. In this review, we discuss the contribution of knowledge gleaned from basic science studies and their implication in the care and outcomes of the human infant within the first few minutes of life and afterwards. We emphasize current knowledge gaps and research that is needed to answer a problem that has taken Nature a considerably longer time to resolve.
Collapse
|
13
|
Mendoza-Hoffmann F, Zarco-Zavala M, Ortega R, García-Trejo JJ. Control of rotation of the F1FO-ATP synthase nanomotor by an inhibitory α-helix from unfolded ε or intrinsically disordered ζ and IF1 proteins. J Bioenerg Biomembr 2018; 50:403-424. [DOI: 10.1007/s10863-018-9773-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 09/13/2018] [Indexed: 12/14/2022]
|
14
|
Mitochondrial - nuclear genetic interaction modulates whole body metabolism, adiposity and gene expression in vivo. EBioMedicine 2018; 36:316-328. [PMID: 30232024 PMCID: PMC6197375 DOI: 10.1016/j.ebiom.2018.08.036] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 08/14/2018] [Accepted: 08/15/2018] [Indexed: 01/16/2023] Open
Abstract
We hypothesized that changes in the mitochondrial DNA (mtDNA) would significantly influence whole body metabolism, adiposity and gene expression in response to diet. Because it is not feasible to directly test these predictions in humans we used Mitochondrial-Nuclear eXchange mice, which have reciprocally exchanged nuclear and mitochondrial genomes between different Mus musculus strains. Results demonstrate that nuclear-mitochondrial genetic background combination significantly alters metabolic efficiency and body composition. Comparative RNA sequencing analysis in adipose tissues also showed a clear influence of the mtDNA on regulating nuclear gene expression on the same nuclear background (up to a 10-fold change in the number of differentially expressed genes), revealing that neither Mendelian nor mitochondrial genetics unilaterally control gene expression. Additional analyses indicate that nuclear-mitochondrial genome combination modulates gene expression in a manner heretofore not described. These findings provide a new framework for understanding complex genetic disease susceptibility.
Collapse
|
15
|
Zarco-Zavala M, Mendoza-Hoffmann F, García-Trejo JJ. Unidirectional regulation of the F 1F O-ATP synthase nanomotor by the ζ pawl-ratchet inhibitor protein of Paracoccus denitrificans and related α-proteobacteria. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2018; 1859:762-774. [PMID: 29886048 DOI: 10.1016/j.bbabio.2018.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 05/28/2018] [Accepted: 06/05/2018] [Indexed: 12/20/2022]
Abstract
The ATP synthase is a reversible nanomotor that gyrates its central rotor clockwise (CW) to synthesize ATP and in counter clockwise (CCW) direction to hydrolyse it. In bacteria and mitochondria, two natural inhibitor proteins, namely the ε and IF1 subunits, prevent the wasteful CCW F1FO-ATPase activity by blocking γ rotation at the αDP/βDP/γ interface of the F1 portion. In Paracoccus denitrificans and related α-proteobacteria, we discovered a different natural F1-ATPase inhibitor named ζ. Here we revise the functional and structural data showing that this novel ζ subunit, although being different to ε and IF1, it also binds to the αDP/βDP/γ interface of the F1 of P. denitrificans. ζ shifts its N-terminal inhibitory domain from an intrinsically disordered protein region (IDPr) to an α-helix when inserted in the αDP/βDP/γ interface. We showed for the first time the key role of a natural ATP synthase inhibitor by the distinctive phenotype of a Δζ knockout mutant in P. denitrificans. ζ blocks exclusively the CCW F1FO-ATPase rotation without affecting the CW-F1FO-ATP synthase turnover, confirming that ζ is important for respiratory bacterial growth by working as a unidirectional pawl-ratchet PdF1FO-ATPase inhibitor, thus preventing the wasteful consumption of cellular ATP. In summary, ζ is a useful model that mimics mitochondrial IF1 but in α-proteobacteria. The structural, functional, and endosymbiotic evolutionary implications of this ζ inhibitor are discussed to shed light on the natural control mechanisms of the three natural inhibitor proteins (ε, ζ, and IF1) of this unique ATP synthase nanomotor, essential for life.
Collapse
Affiliation(s)
- Mariel Zarco-Zavala
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Delegación Coyoacán, Ciudad de México (CDMX), CP 04510, Mexico; Department of Applied Chemistry, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8656, Japan
| | - Francisco Mendoza-Hoffmann
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Delegación Coyoacán, Ciudad de México (CDMX), CP 04510, Mexico
| | - José J García-Trejo
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Delegación Coyoacán, Ciudad de México (CDMX), CP 04510, Mexico.
| |
Collapse
|
16
|
Mendoza-Hoffmann F, Pérez-Oseguera Á, Cevallos MÁ, Zarco-Zavala M, Ortega R, Peña-Segura C, Espinoza-Simón E, Uribe-Carvajal S, García-Trejo JJ. The Biological Role of the ζ Subunit as Unidirectional Inhibitor of the F 1F O-ATPase of Paracoccus denitrificans. Cell Rep 2018; 22:1067-1078. [PMID: 29386127 DOI: 10.1016/j.celrep.2017.12.106] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 09/09/2017] [Accepted: 12/28/2017] [Indexed: 11/16/2022] Open
Abstract
The biological roles of the three natural F1FO-ATPase inhibitors, ε, ζ, and IF1, on cell physiology remain controversial. The ζ subunit is a useful model for deletion studies since it mimics mitochondrial IF1, but in the F1FO-ATPase of Paracoccus denitrificans (PdF1FO), it is a monogenic and supernumerary subunit. Here, we constructed a P. denitrificans 1222 derivative (PdΔζ) with a deleted ζ gene to determine its role in cell growth and bioenergetics. The results show that the lack of ζ in vivo strongly restricts respiratory P. denitrificans growth, and this is restored by complementation in trans with an exogenous ζ gene. Removal of ζ increased the coupled PdF1FO-ATPase activity without affecting the PdF1FO-ATP synthase turnover, and the latter was not affected at all by ζ reconstitution in vitro. Therefore, ζ works as a unidirectional pawl-ratchet inhibitor of the PdF1FO-ATPase nanomotor favoring the ATP synthase turnover to improve respiratory cell growth and bioenergetics.
Collapse
Affiliation(s)
- Francisco Mendoza-Hoffmann
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Delegación Coyoacán, Ciudad de México (CDMX) 04510, México
| | - Ángeles Pérez-Oseguera
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, U.N.A.M., Cuernavaca, Morelos, México
| | - Miguel Ángel Cevallos
- Programa de Genómica Evolutiva, Centro de Ciencias Genómicas, U.N.A.M., Cuernavaca, Morelos, México
| | | | - Raquel Ortega
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Delegación Coyoacán, Ciudad de México (CDMX) 04510, México
| | | | | | | | - José J García-Trejo
- Departamento de Biología, Facultad de Química, Ciudad Universitaria, Universidad Nacional Autónoma de México (U.N.A.M.), Delegación Coyoacán, Ciudad de México (CDMX) 04510, México.
| |
Collapse
|
17
|
Coba de la Peña T, Fedorova E, Pueyo JJ, Lucas MM. The Symbiosome: Legume and Rhizobia Co-evolution toward a Nitrogen-Fixing Organelle? FRONTIERS IN PLANT SCIENCE 2018; 8:2229. [PMID: 29403508 PMCID: PMC5786577 DOI: 10.3389/fpls.2017.02229] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Accepted: 12/19/2017] [Indexed: 05/21/2023]
Abstract
In legume nodules, symbiosomes containing endosymbiotic rhizobial bacteria act as temporary plant organelles that are responsible for nitrogen fixation, these bacteria develop mutual metabolic dependence with the host legume. In most legumes, the rhizobia infect post-mitotic cells that have lost their ability to divide, although in some nodules cells do maintain their mitotic capacity after infection. Here, we review what is currently known about legume symbiosomes from an evolutionary and developmental perspective, and in the context of the different interactions between diazotroph bacteria and eukaryotes. As a result, it can be concluded that the symbiosome possesses organelle-like characteristics due to its metabolic behavior, the composite origin and differentiation of its membrane, the retargeting of host cell proteins, the control of microsymbiont proliferation and differentiation by the host legume, and the cytoskeletal dynamics and symbiosome segregation during the division of rhizobia-infected cells. Different degrees of symbiosome evolution can be defined, specifically in relation to rhizobial infection and to the different types of nodule. Thus, our current understanding of the symbiosome suggests that it might be considered a nitrogen-fixing link in organelle evolution and that the distinct types of legume symbiosomes could represent different evolutionary stages toward the generation of a nitrogen-fixing organelle.
Collapse
Affiliation(s)
- Teodoro Coba de la Peña
- Instituto de Ciencias Agrarias ICA-CSIC, Madrid, Spain
- Centro de Estudios Avanzados en Zonas Áridas (CEAZA), La Serena, Chile
| | - Elena Fedorova
- Instituto de Ciencias Agrarias ICA-CSIC, Madrid, Spain
- K. A. Timiryazev Institute of Plant Physiology, Russian Academy of Science, Moscow, Russia
| | - José J Pueyo
- Instituto de Ciencias Agrarias ICA-CSIC, Madrid, Spain
| | | |
Collapse
|
18
|
Kell DB, Pretorius E. On the translocation of bacteria and their lipopolysaccharides between blood and peripheral locations in chronic, inflammatory diseases: the central roles of LPS and LPS-induced cell death. Integr Biol (Camb) 2016; 7:1339-77. [PMID: 26345428 DOI: 10.1039/c5ib00158g] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We have recently highlighted (and added to) the considerable evidence that blood can contain dormant bacteria. By definition, such bacteria may be resuscitated (and thus proliferate). This may occur under conditions that lead to or exacerbate chronic, inflammatory diseases that are normally considered to lack a microbial component. Bacterial cell wall components, such as the endotoxin lipopolysaccharide (LPS) of Gram-negative strains, are well known as potent inflammatory agents, but should normally be cleared. Thus, their continuing production and replenishment from dormant bacterial reservoirs provides an easy explanation for the continuing, low-grade inflammation (and inflammatory cytokine production) that is characteristic of many such diseases. Although experimental conditions and determinants have varied considerably between investigators, we summarise the evidence that in a great many circumstances LPS can play a central role in all of these processes, including in particular cell death processes that permit translocation between the gut, blood and other tissues. Such localised cell death processes might also contribute strongly to the specific diseases of interest. The bacterial requirement for free iron explains the strong co-existence in these diseases of iron dysregulation, LPS production, and inflammation. Overall this analysis provides an integrative picture, with significant predictive power, that is able to link these processes via the centrality of a dormant blood microbiome that can resuscitate and shed cell wall components.
Collapse
Affiliation(s)
- Douglas B Kell
- School of Chemistry and The Manchester Institute of Biotechnology, The University of Manchester, 131, Princess St, Manchester M1 7DN, Lancs, UK.
| | - Etheresia Pretorius
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Arcadia 0007, South Africa.
| |
Collapse
|
19
|
Lim GS, Barrett CF, Pang CC, Davis JI. Drastic reduction of plastome size in the mycoheterotrophic Thismia tentaculata relative to that of its autotrophic relative Tacca chantrieri. AMERICAN JOURNAL OF BOTANY 2016; 103:1129-37. [PMID: 27335389 DOI: 10.3732/ajb.1600042] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/06/2016] [Indexed: 05/23/2023]
Abstract
PREMISE OF THE STUDY Heterotrophic angiosperms tend to have reduced plastome sizes relative to those of their autotrophic relatives because genes that code for proteins involved in photosynthesis are lost. However, some plastid-encoded proteins may have vital nonphotosynthetic functions, and the plastome therefore may be retained after the loss of photosynthesis. METHODS We sequenced the plastome of the mycoheterotrophic species Thismia tentaculata and a representative of its sister genus, Tacca chantrieri, using next-generation technology, and we compared sequences and structures of genes and genomes of these species. KEY RESULTS The plastome of Tacca chantrieri is similar to those of other autotrophic taxa of Dioscoreaceae, except in a few local rearrangements and one gene loss. The plastome of Thismia tentaculata is ca. 16 kbp long with a quadripartite structure and is among the smallest known plastomes. Synteny is minimal between the plastomes of Tacca chantrieri and Thismia tentaculata. The latter includes only 12 candidate genes, with all except accD involved in protein synthesis. Of the 12 genes, trnE, trnfM, and accD are frequently among the few that remain in depauperate plastomes. CONCLUSIONS The plastome of Thismia tentaculata, like those of most other heterotrophic plants, includes a small number of genes previously suggested to be essential to plastome survival.
Collapse
Affiliation(s)
- Gwynne S Lim
- The New York Botanical Garden, Pfizer Plant Research Laboratory, 2900 Southern Boulevard, Bronx, New York 10458 USA L. H. Bailey Hortorium, Section of Plant Biology, 412 Mann Library Building, Cornell University, Ithaca, New York 14853 USA
| | - Craig F Barrett
- Department of Biology, Life Sciences Building, PO Box 6057, Morgantown, West Virginia 26506 USA
| | - Chun-Chiu Pang
- School of Biological Sciences, Kadoorie Biological Sciences Building, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Jerrold I Davis
- L. H. Bailey Hortorium, Section of Plant Biology, 412 Mann Library Building, Cornell University, Ithaca, New York 14853 USA
| |
Collapse
|
20
|
García-Trejo JJ, Zarco-Zavala M, Mendoza-Hoffmann F, Hernández-Luna E, Ortega R, Mendoza-Hernández G. The Inhibitory Mechanism of the ζ Subunit of the F1FO-ATPase Nanomotor of Paracoccus denitrificans and Related α-Proteobacteria. J Biol Chem 2016; 291:538-46. [PMID: 26546676 PMCID: PMC4705375 DOI: 10.1074/jbc.m115.688143] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 11/02/2015] [Indexed: 01/08/2023] Open
Abstract
The ζ subunit is a novel inhibitor of the F1FO-ATPase of Paracoccus denitrificans and related α-proteobacteria. It is different from the bacterial (ϵ) and mitochondrial (IF1) inhibitors. The N terminus of ζ blocks rotation of the γ subunit of the F1-ATPase of P. denitrificans (Zarco-Zavala, M., Morales-Ríos, E., Mendoza-Hernández, G., Ramírez-Silva, L., Pérez-Hernández, G., and García-Trejo, J. J. (2014) FASEB J. 24, 599-608) by a hitherto unknown quaternary structure that was first modeled here by structural homology and protein docking. The F1-ATPase and F1-ζ models of P. denitrificans were supported by cross-linking, limited proteolysis, mass spectrometry, and functional data. The final models show that ζ enters into F1-ATPase at the open catalytic αE/βE interface, and two partial γ rotations lock the N terminus of ζ in an "inhibition-general core region," blocking further γ rotation, while the ζ globular domain anchors it to the closed αDP/βDP interface. Heterologous inhibition of the F1-ATPase of P. denitrificans by the mitochondrial IF1 supported both the modeled ζ binding site at the αDP/βDP/γ interface and the endosymbiotic α-proteobacterial origin of mitochondria. In summary, the ζ subunit blocks the intrinsic rotation of the nanomotor by inserting its N-terminal inhibitory domain at the same rotor/stator interface where the mitochondrial IF1 or the bacterial ϵ binds. The proposed pawl mechanism is coupled to the rotation of the central γ subunit working as a ratchet but with structural differences that make it a unique control mechanism of the nanomotor to favor the ATP synthase activity over the ATPase turnover in the α-proteobacteria.
Collapse
Affiliation(s)
| | | | | | | | - Raquel Ortega
- From the Departamento de Biología, Facultad de Química, and
| | - Guillermo Mendoza-Hernández
- the Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, Delegación Coyoacán, D.F., CP 04510, México
| |
Collapse
|
21
|
Lee B, Park YS, Lee S, Song GC, Ryu CM. Bacterial RNAs activate innate immunity in Arabidopsis. THE NEW PHYTOLOGIST 2016; 209:785-97. [PMID: 26499893 DOI: 10.1111/nph.13717] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 09/11/2015] [Indexed: 05/20/2023]
Abstract
The common molecular patterns of microbes play a critical role in the regulation of plant innate immunity. However, little is known about the role of nucleic acids in this process in plants. We pre-infiltrated Arabidopsis leaves with total RNAs from Pseudomonas syringae pv. tomato DC3000 (Pto DC3000) and subsequently inoculated these plants with the same bacterial cells. Total Pto DC3000 RNAs pre-infiltrated into Arabidopsis leaves elicited plant immune responses against Pto DC3000. However, sheared RNAs and RNase A application failed to induce immunity, suggesting that intact bacterial RNAs function in plant innate immunity. This notion was supported by the positive regulation of superoxide anion levels, callose deposition, two mitogen-activated protein kinases and defense-related genes observed in bacterial RNA-pre-treated leaves. Intriguingly, the Pto DC3000 population was not compromised in known pattern recognition receptor mutants for chitin, flagellin and elongation factor-Tu (EF-Tu). Plant defense-related mutant analyses further revealed that bacterial RNA-elicited innate immunity was normally required for salicylic and jasmonic acid signaling. Notably, among total RNAs, the abundant bacterial RNA species 16S and 23S ribosomal RNAs were the major determinants of this response. Our findings provide evidence that bacterial RNA serves as a microbe-associated molecular pattern in plants.
Collapse
Affiliation(s)
- Boyoung Lee
- Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea
- Eco-friendly New Material Research Group, KRICT, Daejeon, 305-600, South Korea
| | - Yong-Soon Park
- Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea
- Agricultural Microbiology Division, National Academy of Agricultural Science, Wanju, 565-851, South Korea
| | - Soohyun Lee
- Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea
| | - Geun Cheol Song
- Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea
| | - Choong-Min Ryu
- Molecular Phytobacteriology Laboratory, Superbacteria Research Center, KRIBB, Daejeon, 305-806, South Korea
- Biosystems and Bioengineering Program, University of Science and Technology (UST), Daejeon, 305-350, South Korea
| |
Collapse
|
22
|
Yuen KC, Xu B, Krantz ID, Gerton JL. NIPBL Controls RNA Biogenesis to Prevent Activation of the Stress Kinase PKR. Cell Rep 2015; 14:93-102. [PMID: 26725122 PMCID: PMC4904785 DOI: 10.1016/j.celrep.2015.12.012] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Revised: 10/27/2015] [Accepted: 11/23/2015] [Indexed: 12/30/2022] Open
Abstract
NIPBL, a cohesin loader, has been implicated in transcriptional control and genome organization. Mutations in NIPBL, cohesin, and its deacetylase HDAC8 result in Cornelia de Lange syndrome. We report activation of the RNA-sensing kinase PKR in human lymphoblastoid cell lines carrying NIPBL or HDAC8 mutations, but not SMC1A or SMC3 mutations. PKR activation can be triggered by unmodified RNAs. Gene expression profiles in NIPBL-deficient lymphoblastoid cells and mouse embryonic stem cells reveal lower expression of genes involved in RNA processing and modification. NIPBL mutant lymphoblastoid cells show reduced proliferation and protein synthesis with increased apoptosis, all of which are partially reversed by a PKR inhibitor. Non-coding RNAs from an NIPBL mutant line had less m6A modification and activated PKR activity in vitro. This study provides insight into the molecular pathology of Cornelia de Lange syndrome by establishing a relationship between NIPBL and HDAC8 mutations and PKR activation.
Collapse
Affiliation(s)
- Kobe C Yuen
- Stowers Institute for Medical Research (SIMR), 1000 East 50(th) Street, Kansas City, MO 64110, USA
| | - Baoshan Xu
- Stowers Institute for Medical Research (SIMR), 1000 East 50(th) Street, Kansas City, MO 64110, USA
| | - Ian D Krantz
- Children's Hospital of Philadelphia, Division of Human Genetics, 3615 Civic Center Boulevard, Philadelphia, PA 19104, USA
| | - Jennifer L Gerton
- Stowers Institute for Medical Research (SIMR), 1000 East 50(th) Street, Kansas City, MO 64110, USA; University of Kansas School of Medicine, Department of Biochemistry and Molecular Biology, 3901 Rainbow Boulevard, Kansas City, KS 66160, USA.
| |
Collapse
|
23
|
Clark IA, Vissel B. Amyloid β: one of three danger-associated molecules that are secondary inducers of the proinflammatory cytokines that mediate Alzheimer's disease. Br J Pharmacol 2015; 172:3714-27. [PMID: 25939581 PMCID: PMC4523330 DOI: 10.1111/bph.13181] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Revised: 03/31/2015] [Accepted: 04/14/2015] [Indexed: 12/11/2022] Open
Abstract
This review concerns how the primary inflammation preceding the generation of certain key damage-associated molecular patterns (DAMPs) arises in Alzheimer's disease (AD). In doing so, it places soluble amyloid β (Aβ), a protein hitherto considered as a primary initiator of AD, in a novel perspective. We note here that increased soluble Aβ is one of the proinflammatory cytokine-induced DAMPs recognized by at least one of the toll-like receptors on and in various cell types. Moreover, Aβ is best regarded as belonging to a class of DAMPs, as do the S100 proteins and HMBG1, that further exacerbate production of these same proinflammatory cytokines, which are already enhanced, and induces them further. Moreover, variation in levels of other DAMPs of this same class in AD may explain why normal elderly patients can exhibit high Aβ plaque levels, and why removing Aβ or its plaque does not retard disease progression. It may also explain why mouse transgenic models, having been designed to generate high Aβ, can be treated successfully by this approach.
Collapse
Affiliation(s)
- I A Clark
- Biomedical Sciences and Biochemistry, Research School of Biology, Australian National UniversityCanberra, ACT, Australia
| | - B Vissel
- Neurodegeneration Research Group, Garvan InstituteSydney, NSW, Australia
| |
Collapse
|
24
|
González-Cabaleiro R, Ofiţeru ID, Lema JM, Rodríguez J. Microbial catabolic activities are naturally selected by metabolic energy harvest rate. ISME JOURNAL 2015; 9:2630-41. [PMID: 26161636 DOI: 10.1038/ismej.2015.69] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 03/18/2015] [Accepted: 03/25/2015] [Indexed: 01/06/2023]
Abstract
The fundamental trade-off between yield and rate of energy harvest per unit of substrate has been largely discussed as a main characteristic for microbial established cooperation or competition. In this study, this point is addressed by developing a generalized model that simulates competition between existing and not experimentally reported microbial catabolic activities defined only based on well-known biochemical pathways. No specific microbial physiological adaptations are considered, growth yield is calculated coupled to catabolism energetics and a common maximum biomass-specific catabolism rate (expressed as electron transfer rate) is assumed for all microbial groups. Under this approach, successful microbial metabolisms are predicted in line with experimental observations under the hypothesis of maximum energy harvest rate. Two microbial ecosystems, typically found in wastewater treatment plants, are simulated, namely: (i) the anaerobic fermentation of glucose and (ii) the oxidation and reduction of nitrogen under aerobic autotrophic (nitrification) and anoxic heterotrophic and autotrophic (denitrification) conditions. The experimentally observed cross feeding in glucose fermentation, through multiple intermediate fermentation pathways, towards ultimately methane and carbon dioxide is predicted. Analogously, two-stage nitrification (by ammonium and nitrite oxidizers) is predicted as prevailing over nitrification in one stage. Conversely, denitrification is predicted in one stage (by denitrifiers) as well as anammox (anaerobic ammonium oxidation). The model results suggest that these observations are a direct consequence of the different energy yields per electron transferred at the different steps of the pathways. Overall, our results theoretically support the hypothesis that successful microbial catabolic activities are selected by an overall maximum energy harvest rate.
Collapse
Affiliation(s)
- Rebeca González-Cabaleiro
- Institute Centre for Water and Environment (iWATER), Department of Chemical and Environmental Engineering (CEE), Masdar Institute of Science and Technology, Abu Dhabi, UAE.,Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, Santiago de Compostela, Galicia, Spain
| | - Irina D Ofiţeru
- Institute Centre for Water and Environment (iWATER), Department of Chemical and Environmental Engineering (CEE), Masdar Institute of Science and Technology, Abu Dhabi, UAE
| | - Juan M Lema
- Department of Chemical Engineering, Institute of Technology, University of Santiago de Compostela, Santiago de Compostela, Galicia, Spain
| | - Jorge Rodríguez
- Institute Centre for Water and Environment (iWATER), Department of Chemical and Environmental Engineering (CEE), Masdar Institute of Science and Technology, Abu Dhabi, UAE
| |
Collapse
|
25
|
Kell D, Potgieter M, Pretorius E. Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology. F1000Res 2015; 4:179. [PMID: 26629334 PMCID: PMC4642849 DOI: 10.12688/f1000research.6709.2] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/04/2015] [Indexed: 01/28/2023] Open
Abstract
For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.
Collapse
Affiliation(s)
- Douglas Kell
- School of Chemistry and The Manchester Institute of Biotechnology, The University of Manchester, Manchester, Lancashire, M1 7DN, UK
| | - Marnie Potgieter
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Arcadia, 0007, South Africa
| | - Etheresia Pretorius
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Arcadia, 0007, South Africa
| |
Collapse
|
26
|
Kell D, Potgieter M, Pretorius E. Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology. F1000Res 2015; 4:179. [PMID: 26629334 DOI: 10.12688/f1000research.6709.1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/29/2015] [Indexed: 01/28/2023] Open
Abstract
For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.
Collapse
Affiliation(s)
- Douglas Kell
- School of Chemistry and The Manchester Institute of Biotechnology, The University of Manchester, Manchester, Lancashire, M1 7DN, UK
| | - Marnie Potgieter
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Arcadia, 0007, South Africa
| | - Etheresia Pretorius
- Department of Physiology, Faculty of Health Sciences, University of Pretoria, Arcadia, 0007, South Africa
| |
Collapse
|
27
|
Wang SP, Yang H, Wu JW, Gauthier N, Fukao T, Mitchell GA. Metabolism as a tool for understanding human brain evolution: lipid energy metabolism as an example. J Hum Evol 2014; 77:41-9. [PMID: 25488255 DOI: 10.1016/j.jhevol.2014.06.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 03/24/2014] [Accepted: 06/18/2014] [Indexed: 10/24/2022]
Abstract
Genes and the environment both influence the metabolic processes that determine fitness. To illustrate the importance of metabolism for human brain evolution and health, we use the example of lipid energy metabolism, i.e. the use of fat (lipid) to produce energy and the advantages that this metabolic pathway provides for the brain during environmental energy shortage. We briefly describe some features of metabolism in ancestral organisms, which provided a molecular toolkit for later development. In modern humans, lipid energy metabolism is a regulated multi-organ pathway that links triglycerides in fat tissue to the mitochondria of many tissues including the brain. Three important control points are each suppressed by insulin. (1) Lipid reserves in adipose tissue are released by lipolysis during fasting and stress, producing fatty acids (FAs) which circulate in the blood and are taken up by cells. (2) FA oxidation. Mitochondrial entry is controlled by carnitine palmitoyl transferase 1 (CPT1). Inside the mitochondria, FAs undergo beta oxidation and energy production in the Krebs cycle and respiratory chain. (3) In liver mitochondria, the 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) pathway produces ketone bodies for the brain and other organs. Unlike most tissues, the brain does not capture and metabolize circulating FAs for energy production. However, the brain can use ketone bodies for energy. We discuss two examples of genetic metabolic traits that may be advantageous under most conditions but deleterious in others. (1) A CPT1A variant prevalent in Inuit people may allow increased FA oxidation under nonfasting conditions but also predispose to hypoglycemic episodes. (2) The thrifty genotype theory, which holds that energy expenditure is efficient so as to maximize energy stores, predicts that these adaptations may enhance survival in periods of famine but predispose to obesity in modern dietary environments.
Collapse
Affiliation(s)
- Shu Pei Wang
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, 3175 Côte Sainte-Catherine, Montreal H3T 1C5, QC, Canada
| | - Hao Yang
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, 3175 Côte Sainte-Catherine, Montreal H3T 1C5, QC, Canada; Laboratory of Animal Fat Deposition and Muscle Development, College of Animal Science and Technology, Northwest A&F University, Yangling 712100, Shaanxi, China
| | - Jiang Wei Wu
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, 3175 Côte Sainte-Catherine, Montreal H3T 1C5, QC, Canada
| | - Nicolas Gauthier
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, 3175 Côte Sainte-Catherine, Montreal H3T 1C5, QC, Canada
| | - Toshiyuki Fukao
- Department of Pediatrics, Gifu University School of Medicine, Gifu 500, Japan
| | - Grant A Mitchell
- Division of Medical Genetics, Department of Pediatrics, Université de Montréal and CHU Sainte-Justine, 3175 Côte Sainte-Catherine, Montreal H3T 1C5, QC, Canada.
| |
Collapse
|
28
|
Abstract
Holistic emerging approaches allow us to understand that every organism is the result of integration mechanisms observed at every level of nature: integration of DNA from virus and bacteria in metazoans, endosymbiotic relationships and holobionts. Horizontal gene transfer events in Bacteria, Archaea and Eukaryotes have resulted in the chimeric nature of genomes. As a continuity of this genomic landscape, the human body contains more bacterial than human cells. Human microbiome has co-evolved with the human being as a unity called holobiont. The loss of part of our microbiome along evolution can explain the continuous increasing incidence of immune and inflammatory-related diseases. Life is a continuous process in which the organism experiences its environment and this interaction impacts in the epigenetic system and the genomic structure. The emerging perspectives restitute the great importance of Lamarck's theoretical contributions (the milieu) and Darwin's pangenesis theory.
Collapse
|
29
|
Clark IA, Vissel B. Treatment implications of the altered cytokine-insulin axis in neurodegenerative disease. Biochem Pharmacol 2013; 86:862-71. [PMID: 23939185 DOI: 10.1016/j.bcp.2013.07.030] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Revised: 07/24/2013] [Accepted: 07/25/2013] [Indexed: 11/15/2022]
Abstract
The disappointments of a series of large anti-amyloid trials have brought home the point that until the driving force behind Alzheimer's disease, and the way it causes harm, are firmly established and accepted, researchers will remain ill-equipped to find a way to treat patients successfully. The origin of inflammation in neurodegenerative diseases is still an open question. We champion and expand the argument that a shift in intracellular location of α-synuclein, thereby moving a key methylation enzyme from the nucleus, provides global hypomethylation of patients' cerebral DNA that, through being sensed by TLR9, initiates production of the cytokines that drive these cerebral inflammatory states. After providing a background on the relevant inflammatory cytokines, this commentary then discusses many of the known alternatives to the primary amyloid argument of the pathogenesis of Alzheimer's disease, and the treatment approaches they provide. A key point to appreciate is the weight of evidence that inflammatory cytokines, largely through increasing insulin resistance and thereby reducing the strength of the ubiquitously important signaling mediated by insulin, bring together most of these treatments under development for neurodegenerative disease under the one roof. Moreover, the principles involved apply to a wide range of inflammatory diseases on both sides of the blood brain barrier.
Collapse
Affiliation(s)
- Ian A Clark
- Research School of Biology, Australian National University, Canberra, Australia.
| | | |
Collapse
|
30
|
Parasites or cohabitants: cruel omnipresent usurpers or creative "éminences grises"? J Parasitol Res 2011; 2011:214174. [PMID: 21785696 PMCID: PMC3140032 DOI: 10.1155/2011/214174] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Accepted: 04/06/2011] [Indexed: 12/31/2022] Open
Abstract
This paper presents many types of interplays between parasites and the host, showing the history of parasites, the effects of parasites on the outcome of wars, invasions, migrations, and on the development of numerous regions of the globe, and the impact of parasitic diseases on the society and on the course of human evolution. It also emphasizes the pressing need to change the look at the parasitism phenomenon, proposing that the term “cohabitant” is more accurate than parasite, because every living being, from bacteria to mammals, is a consortium of living beings in the pangenome. Even the term parasitology should be replaced by cohabitology because there is no parasite alone and host alone: both together compose a new adaptive system: the parasitized-host or the cohabitant-cohabited being. It also suggests switching the old paradigm based on attrition and destruction, to a new one founded on adaptation and living together.
Collapse
|
31
|
Oliver KR, Greene WK. Mobile DNA and the TE-Thrust hypothesis: supporting evidence from the primates. Mob DNA 2011; 2:8. [PMID: 21627776 PMCID: PMC3123540 DOI: 10.1186/1759-8753-2-8] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 05/31/2011] [Indexed: 02/07/2023] Open
Abstract
Transposable elements (TEs) are increasingly being recognized as powerful facilitators of evolution. We propose the TE-Thrust hypothesis to encompass TE-facilitated processes by which genomes self-engineer coding, regulatory, karyotypic or other genetic changes. Although TEs are occasionally harmful to some individuals, genomic dynamism caused by TEs can be very beneficial to lineages. This can result in differential survival and differential fecundity of lineages. Lineages with an abundant and suitable repertoire of TEs have enhanced evolutionary potential and, if all else is equal, tend to be fecund, resulting in species-rich adaptive radiations, and/or they tend to undergo major evolutionary transitions. Many other mechanisms of genomic change are also important in evolution, and whether the evolutionary potential of TE-Thrust is realized is heavily dependent on environmental and ecological factors. The large contribution of TEs to evolutionary innovation is particularly well documented in the primate lineage. In this paper, we review numerous cases of beneficial TE-caused modifications to the genomes of higher primates, which strongly support our TE-Thrust hypothesis.
Collapse
Affiliation(s)
- Keith R Oliver
- School of Biological Sciences and Biotechnology, Faculty of Science and Engineering, Murdoch University, Perth W. A. 6150, Australia
| | - Wayne K Greene
- School of Veterinary and Biomedical Sciences, Faculty of Health Sciences, Murdoch University, Perth W. A. 6150, Australia
| |
Collapse
|
32
|
|
33
|
|
34
|
Along a TNF-paved road from dead parasites in red cells to cerebral malaria, and beyond. Parasitology 2009; 136:1457-68. [DOI: 10.1017/s0031182009006088] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
SUMMARYThis is a personal account of how tumour necrosis factor (TNF) the prototype of a group of host-origin mediators, often known as pro-inflammatory cytokines, came into parasitology, and was subsequently realised to be central to the pathogenesis of most disease pathology. This contribution summarizes an example of how a curiosity-driven outsider, with initially no intention of heading this way, and no relevant experience, and with no more than the simplest of plans but an ambition to read as widely as it takes, and (most importantly) allowed to follow his head, can be what is required to give fresh insight into understanding a disease. It also gives the author's views on aspects of how the field of malaria disease pathogenesis seems to be developing. The hope is to inspire another generation to follow a similarly original course.
Collapse
|
35
|
Nallagatla SR, Bevilacqua PC. Nucleoside modifications modulate activation of the protein kinase PKR in an RNA structure-specific manner. RNA (NEW YORK, N.Y.) 2008; 14:1201-1213. [PMID: 18426922 PMCID: PMC2390794 DOI: 10.1261/rna.1007408] [Citation(s) in RCA: 111] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Accepted: 02/18/2008] [Indexed: 05/26/2023]
Abstract
The human interferon-induced protein kinase PKR is a key component of innate immunity, a process in which it senses pathogenic RNA. PKR consists of an N-terminal dsRNA-binding domain (dsRBD) and a C-terminal kinase domain. Upon binding long (>33 base pairs) stretches of pathogenic dsRNA, PKR undergoes autophosphorylation, which activates it to phosphorylate eIF2alpha, leading to inhibition of translation initiation. Many cellular and viral transcripts contain nucleoside modifications, and these could affect PKR activation. For example, a 5'-triphosphate confers the ability of relatively unstructured transcripts to activate PKR. Effects of internal RNA modifications on PKR activation have not been reported. Herein, PKR activation by ssRNA and dsRNA containing internal nucleobase, sugar, and phosphodiester modifications is analyzed. We find that for 5'-triphosphate-containing ssRNA, most base and sugar modifications abrogate activation, although 2'-fluoro-modified ssRNA does not, indicative of a critical role for hydrogen bonding at the ribose sugar. In the case of dsRNA, a more limited set of nucleoside modifications affect PKR activation. Watson-Crick base-pairing is required for activation, and some minor groove modifications abrogate activation while major groove modifications have little effect. Surprisingly, GU wobble pairs also largely abrogate dsRNA-mediated activation when present at modest levels. Modifications to dsRNA that abrogate activation have no significant effect on dsRBD binding, allowing such RNAs to act as inhibitors and suggesting a nonequivalence of binding ability and activation. Overall, the findings indicate that nucleoside modifications and wobble pairing may serve to discriminate self-RNA and pathogenic RNA in innate immunity.
Collapse
Affiliation(s)
- Subba Rao Nallagatla
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | | |
Collapse
|
36
|
Summerer M, Sonntag B, Sommaruga R. CILIATE-SYMBIONT SPECIFICITY OF FRESHWATER ENDOSYMBIOTIC CHLORELLA (TREBOUXIOPHYCEAE, CHLOROPHYTA)(1). JOURNAL OF PHYCOLOGY 2008; 44:77-84. [PMID: 27041043 DOI: 10.1111/j.1529-8817.2007.00455.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The nature of Chlorella symbioses in invertebrates and protists has attracted much interest, but the uncertain taxonomy of the algal partner has constrained a deeper ecological understanding of this symbiosis. We sequenced parts of the nuclear 18S rDNA, the internal transcribed spacer (ITS)-1 region, and the chloroplast 16S rDNA of several Chlorella isolated from pelagic ciliate species of different lakes, Paramecium bursaria symbionts, and free-living Chlorella to elucidate phylogenetic relationships of Chlorella-like algae and to assess their host specificity. Sequence analyses resulted in well-resolved phylogenetic trees providing strong statistical support for a homogenous 'zoochlorellae' group of different ciliate species from one lake, but clearly different Chlorella in one of those ciliate species occurring in another lake. The two Chlorella strains isolated from the same ciliate species, but from lakes having a 10-fold difference in underwater UV transparency, also presented a distinct physiological trait, such as the ability to synthesize UV-absorbing substances known as mycosporine-like amino acids (MAAs). Algal symbionts of all P. bursaria strains of different origin resolved in one clade apart from the other ciliate symbionts but split into two distinct lineages, suggesting the existence of a biogeographic pattern. Overall, our results suggest a high degree of species specificity but also hint at the importance of physiological adaptation in symbiotic Chlorella.
Collapse
Affiliation(s)
- Monika Summerer
- Laboratory of Photobiology and Plankton Ecology, Institute of Ecology, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - Bettina Sonntag
- Laboratory of Photobiology and Plankton Ecology, Institute of Ecology, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| | - Ruben Sommaruga
- Laboratory of Photobiology and Plankton Ecology, Institute of Ecology, University of Innsbruck, Technikerstrasse 25, 6020 Innsbruck, Austria
| |
Collapse
|
37
|
Kakkar P, Singh BK. Mitochondria: a hub of redox activities and cellular distress control. Mol Cell Biochem 2007; 305:235-53. [PMID: 17562131 DOI: 10.1007/s11010-007-9520-8] [Citation(s) in RCA: 167] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Accepted: 05/16/2007] [Indexed: 02/07/2023]
Abstract
In their reductionist approach in unraveling phenomena inside the cell, scientists in recent times have focused attention to mitochondria. An organelle with peculiar evolutionary history and organization, it is turning out to be an important cell survival switch. Besides controlling bioenergetics of a cell it also has its own genetic machinery which codes 37 genes. It is a major source of generation of reactive oxygen species, acts as a safety device against toxic increases of cytosolic Ca2+ and its membrane permeability transition is a critical control point in cell death. Redox status of mitochondria is important in combating oxidative stress and maintaining membrane permeability. Importance of mitochondria in deciding the response of cell to multiplicity of physiological and genetic stresses, inter-organelle communication, and ultimate cell survival is constantly being unraveled and discussed in this review. Mitochondrial events involved in apoptosis and necrotic cell death, such as activation of Bcl-2 family proteins, formation of permeability transition pore, release of cytochrome c and apoptosis inducing factors, activation of caspase cascade, and ultimate cell death is the focus of attention not only for cell biologists, but also for toxicologists in unraveling stress responses. Mutations caused by ROS to mitochondrial DNA, its inability to repair it completely and creation of a vicious cycle of mutations along with role of Bcl-2 family genes and proteins has been implicated in many diseases where mitochondrial dysfunctions play a key role. New therapeutic approaches toward targeting low molecular weight compounds to mitochondria, including antioxidants is a step toward nipping the stress in the bud.
Collapse
Affiliation(s)
- Poonam Kakkar
- Herbal Research Section, Industrial Toxicology Research Centre, P.O. Box-80, M G Marg, Lucknow, 226 001, India.
| | | |
Collapse
|
38
|
Abstract
Water was called by Szent-Gyorgi "life's mater and matrix, mother and medium." This chapter considers both aspects of his statement. Many astrobiologists argue that some, if not all, of Earth's water arrived during cometary bombardments. Amorphous water ices of comets possibly facilitated organization of complex organic molecules, kick-starting prebiotic evolution. In Gaian theory, Earth retains its water as a consequence of biological activity. The cell cytomatrix is a proteinaceous matrix/lattice incorporating the cytoskeleton, a pervasive, holistic superstructural network that integrates metabolic pathways. Enzymes of metabolic pathways are ordered in supramolecular clusters (metabolons) associated with cytoskeleton and/or membranes. Metabolic intermediates are microchanneled through metabolons without entering a bulk aqueous phase. Rather than being free in solution, even major signaling ions are probably clustered in association with the cytomatrix. Chloroplasts and mitochondria, like bacteria and archaea, also contain a cytoskeletal lattice, metabolons, and channel metabolites. Eukaryotic metabolism is mathematically a scale-free or small-world network. Enzyme clusters of bacterial origin are incorporated at a pathway level that is architecturally archaean. The eucaryotic cell may be a product of serial endosymbiosis, a chimera. Cell cytoplasm is approximately 80% water. Water is indisputably a conserved structural element of proteins, essential to their folding, specificity, ligand binding, and to enzyme catalysis. The vast literature of organized cell water has long argued that the cytomatrix and cell water are an entire system, a continuum, or gestalt. Alternatives are offered to mainstream explanations of cell electric potentials, ion channel, enzyme, and motor protein function, in terms of high-order cooperative systems of ions, water, and macromolecules. This chapter describes some prominent concepts of organized cell water, including vicinal water network theory, the association-induction hypothesis, wave-cluster theory, phase-gel transition theories, and theories of low- and high-density water polymorphs.
Collapse
Affiliation(s)
- V A Shepherd
- Department of Biophysics, School of Physics, The University of NSW NSW 2052, Sydney, Australia
| |
Collapse
|
39
|
Pradeu T. [Uncertainties about the self and the issue of the proper theoretical model in immunology]. Med Sci (Paris) 2005; 21:872-5. [PMID: 16197907 DOI: 10.1051/medsci/20052110872] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Theoretical immunology constitutes a critical basis of all medical discoveries. Immunology has been dominated since the 1940s by the self/nonself model. Here we try to shed light on the origins of this theoretical model and to show how and why this model has been called into question during the last thirty years. This paper has three aims. Firstly, we explore the sources of the immune self, going upstream from immunology to ecology-biology, psychology and eventually philosophy. Here the key questions : is the immune self really analogous with the philosophical and psychological selves in which it originates? What is the signification and adequacy of such a conceptual borrowing? We suggest that the << self >> vocabulary in immunology is not clear and precise. Secondly, we present the experimental inadequacies of the self/non-self model. We show then how both the vagueness of the term << self >> and these experimental flaws casted doubt on theories of immunology. Among the several models that have been proposed recently, none has attracted a consensus. Some immunologists have even suggested that immunology should rid itself of theorical concerns and concentrate on molecular aspects. This suggestion, however, is unacceptable\; hence it is still necessary to find a theoretical framework for immunology. Finally, we try to suggest a way to escape this uncomfortable situation of doubt. The immune << self >> and the immune << system >> (<< network >>) are rooted in strong metaphysical conceptions of identity, the main characteristic of which is to consider the organism as an enclosed and self-constructing entity. By contrast, based on experimental data about immune tolerance and host-pathogen interactions, we propose to consider organisms as open entities. To what theory does this conception lead? What would be the consequences of such a theory with regard to medical aspects?
Collapse
Affiliation(s)
- Thomas Pradeu
- Institut d'histoire et de philosophie des sciences et des techniques (IHPST), Université Paris 1 Panthéon-Sorbonne, France.
| |
Collapse
|
40
|
Karikó K, Buckstein M, Ni H, Weissman D. Suppression of RNA recognition by Toll-like receptors: the impact of nucleoside modification and the evolutionary origin of RNA. Immunity 2005; 23:165-75. [PMID: 16111635 DOI: 10.1016/j.immuni.2005.06.008] [Citation(s) in RCA: 1469] [Impact Index Per Article: 77.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2005] [Revised: 05/26/2005] [Accepted: 06/15/2005] [Indexed: 10/25/2022]
Abstract
DNA and RNA stimulate the mammalian innate immune system through activation of Toll-like receptors (TLRs). DNA containing methylated CpG motifs, however, is not stimulatory. Selected nucleosides in naturally occurring RNA are also methylated or otherwise modified, but the immunomodulatory effects of these alterations remain untested. We show that RNA signals through human TLR3, TLR7, and TLR8, but incorporation of modified nucleosides m5C, m6A, m5U, s2U, or pseudouridine ablates activity. Dendritic cells (DCs) exposed to such modified RNA express significantly less cytokines and activation markers than those treated with unmodified RNA. DCs and TLR-expressing cells are potently activated by bacterial and mitochondrial RNA, but not by mammalian total RNA, which is abundant in modified nucleosides. We conclude that nucleoside modifications suppress the potential of RNA to activate DCs. The innate immune system may therefore detect RNA lacking nucleoside modification as a means of selectively responding to bacteria or necrotic tissue.
Collapse
Affiliation(s)
- Katalin Karikó
- Department of Neurosurgery, University of Pennsylvania School of Medicine, Philadelphia, 19104, USA.
| | | | | | | |
Collapse
|
41
|
Jargeat P, Cosseau C, Ola'h B, Jauneau A, Bonfante P, Batut J, Bécard G. Isolation, free-living capacities, and genome structure of "Candidatus Glomeribacter gigasporarum," the endocellular bacterium of the mycorrhizal fungus Gigaspora margarita. J Bacteriol 2004; 186:6876-84. [PMID: 15466041 PMCID: PMC522191 DOI: 10.1128/jb.186.20.6876-6884.2004] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2004] [Accepted: 07/19/2004] [Indexed: 11/20/2022] Open
Abstract
"Candidatus Glomeribacter gigasporarum" is an endocellular beta-proteobacterium present in the arbuscular mycorrhizal (AM) fungus Gigaspora margarita. We established a protocol to isolate "Ca. Glomeribacter gigasporarum" from its host which allowed us to carry out morphological, physiological, and genomic investigations on purified bacteria. They are rod shaped, with a cell wall typical of gram-negative bacteria and a cytoplasm rich in ribosomes, and they present no flagella or pili. Isolated bacteria could not be grown in any of the 19 culture media tested, but they could be kept alive for up to 4 weeks. PCR-based investigations of purified DNA from isolated bacteria did not confirm the presence of all genes previously assigned to "Ca. Glomeribacter gigasporarum." In particular, the presence of nif genes could not be detected. Pulsed-field gel electrophoresis analyses allowed us to estimate the genome size of "Ca. Glomeribacter gigasporarum" to approximately 1.4 Mb with a ca. 750-kb chromosome and a 600- to 650-kb plasmid. This is the smallest genome known for a beta-proteobacterium. Such small genome sizes are typically found in endocellular bacteria living permanently in their host. Altogether, our data suggest that "Ca. Glomeribacter gigasporarum" is an ancient obligate endocellular bacterium of the AM fungus G. margarita.
Collapse
Affiliation(s)
- P Jargeat
- UMR 5546 CNRS-University Paul Sabatier, 24, chemin de Borde-Rouge, BP 17, Auzeville 31326, Castanet-Tolosan, France
| | | | | | | | | | | | | |
Collapse
|
42
|
Abstract
Free-living amoebae feed on bacteria, fungi, and algae. However, some microorganisms have evolved to become resistant to these protists. These amoeba-resistant microorganisms include established pathogens, such as Cryptococcus neoformans, Legionella spp., Chlamydophila pneumoniae, Mycobacterium avium, Listeria monocytogenes, Pseudomonas aeruginosa, and Francisella tularensis, and emerging pathogens, such as Bosea spp., Simkania negevensis, Parachlamydia acanthamoebae, and Legionella-like amoebal pathogens. Some of these amoeba-resistant bacteria (ARB) are lytic for their amoebal host, while others are considered endosymbionts, since a stable host-parasite ratio is maintained. Free-living amoebae represent an important reservoir of ARB and may, while encysted, protect the internalized bacteria from chlorine and other biocides. Free-living amoebae may act as a Trojan horse, bringing hidden ARB within the human "Troy," and may produce vesicles filled with ARB, increasing their transmission potential. Free-living amoebae may also play a role in the selection of virulence traits and in adaptation to survival in macrophages. Thus, intra-amoebal growth was found to enhance virulence, and similar mechanisms seem to be implicated in the survival of ARB in response to both amoebae and macrophages. Moreover, free-living amoebae represent a useful tool for the culture of some intracellular bacteria and new bacterial species that might be potential emerging pathogens.
Collapse
Affiliation(s)
- Gilbert Greub
- Unité des Rickettsies, Faculté de Médecine, Université de la Méditerranée, Marseille, France
| | | |
Collapse
|
43
|
Bianciotto V, Genre A, Jargeat P, Lumini E, Bécard G, Bonfante P. Vertical transmission of endobacteria in the arbuscular mycorrhizal fungus Gigaspora margarita through generation of vegetative spores. Appl Environ Microbiol 2004; 70:3600-8. [PMID: 15184163 PMCID: PMC427789 DOI: 10.1128/aem.70.6.3600-3608.2004] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2003] [Accepted: 03/03/2004] [Indexed: 12/31/2022] Open
Abstract
Arbuscular mycorrhizal (AM) fungi living in symbiotic association with the roots of vascular plants have also been shown to host endocellular rod-shaped bacteria. Based on their ribosomal sequences, these endobacteria have recently been identified as a new taxon, Candidatus Glomeribacter gigasporarum. In order to investigate the cytoplasmic stability of the endobacteria in their fungal host and their transmission during AM fungal reproduction (asexual), a system based on transformed carrot roots and single-spore inocula of Gigaspora margarita was used. Under these in vitro sterile conditions, with no risk of horizontal contamination, the propagation of endobacteria could be monitored, and it was shown, by using primers designed for both 16S and 23S ribosomal DNAs, to occur through several vegetative spore generations (SG0 to SG4). A method of confocal microscopy for quantifying the density of endobacteria in spore cytoplasm was designed and applied; endobacteria were consistently found in all of the spore generations, although their number rapidly decreased from SG0 to SG4. The study demonstrates that a vertical transmission of endobacteria takes place through the fungal vegetative generations (sporulation) of an AM fungus, indicating that active bacterial proliferation occurs in the coenocytic mycelium of the fungus, and suggests that these bacteria are obligate endocellular components of their AM fungal host.
Collapse
Affiliation(s)
- V Bianciotto
- Dipartimento di Biologia Vegetale dell'Università e Istituto per la Protezione delle Piante CNR, 10125 Turin, Italy
| | | | | | | | | | | |
Collapse
|
44
|
Affiliation(s)
- Eric Bapteste
- Unité Mixte de Recherche 7622 CNRS, Université Paris 6, 9 quai Saint Bernard, Bâtiment B, 75005 Paris, France.
| | | |
Collapse
|
45
|
Abstract
In this brief review, literature references are given to researches--involving diverse species of protists--that support the author's firm conviction that the biological world of today absolutely requires the presence of numerous of these generally small and unicelled organisms if it is to survive. Examples supplied come from areas within the field of protistology sensu lato as widely separated as basic phycological research on photosynthesis and protozoological/medical/biomedical investigations on malaria and other pathogens of human beings. Emphasis is primarily on the most relevant works of the past 10-15 years, although historically highly significant papers of older vintage require at least indirect--and occasionally direct--citation.
Collapse
|
46
|
Sánchez MS, Hastings A. Uniform vertical transmission and selection in a host–symbiont system. Non-random symbiont distribution generates apparent differential selection. J Theor Biol 2003; 225:517-30. [PMID: 14615211 DOI: 10.1016/s0022-5193(03)00303-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We investigate the survival, prevalence, and distribution of a symbiont in its host population when the forces of vertical transmission (beta) and symbiont-induced selection (s) are uniform (invariant across host genotypes). We use host-symbiont disequilibria to quantify the role played by non-random associations between host genotypes and the symbiont in altering host genetic structure. Results show a larger part of the parameter space permits symbiont survival under mutualism (beta>/=0.25) than parasitism (beta>0.5). The nonlinear interaction between beta and s determines symbiont survival and prevalence at equilibrium; initial symbiont prevalence is a factor only in a small number of parameter combinations. The symbiont's non-random distribution generates apparent differential selection, when selective differences across host genotypes and alleles exist under uniform selection. The direction of change in host allele frequencies is determined exclusively by the signs of s and the allelic disequilibrium. Disequilibria cannot be created or maintained, and heterozygote disequilibrium changes sign in a greater number of runs and at higher magnitudes than homozygote disequilibria. This investigation increases our understanding of the interactions between vertical transmission and selection, and their effect on the coevolutionary dynamics and final states of interacting species under different selection regimes.
Collapse
Affiliation(s)
- María S Sánchez
- Department of Environmental Science and Policy, University of California, Davis, CA 95616, USA.
| | | |
Collapse
|
47
|
Araújo A, Jansen AM, Bouchet F, Reinhard K, Ferreira LF. Parasitism, the diversity of life, and paleoparasitology. Mem Inst Oswaldo Cruz 2003; 98 Suppl 1:5-11. [PMID: 12687756 DOI: 10.1590/s0074-02762003000900003] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The parasite-host-environment system is dynamic, with several points of equilibrium. This makes it difficult to trace the thresholds between benefit and damage, and therefore, the definitions of commensalism, mutualism, and symbiosis become worthless. Therefore, the same concept of parasitism may encompass commensalism, mutualism, and symbiosis. Parasitism is essential for life. Life emerged as a consequence of parasitism at the molecular level, and intracellular parasitism created evolutive events that allowed species to diversify. An ecological and evolutive approach to the study of parasitism is presented here. Studies of the origin and evolution of parasitism have new perspectives with the development of molecular paleoparasitology, by which ancient parasite and host genomes can be recovered from disappeared populations. Molecular paleoparasitology points to host-parasite co-evolutive mechanisms of evolution traceable through genome retrospective studies.
Collapse
Affiliation(s)
- Adauto Araújo
- Escola Nacional de Saúde Pública-Fiocruz, Rua Leopoldo Bulhões 1480, 21041-210 Rio de Janeiro, RJ, Brasil.
| | | | | | | | | |
Collapse
|
48
|
Rudhe C, Clifton R, Whelan J, Glaser E. N-terminal domain of the dual-targeted pea glutathione reductase signal peptide controls organellar targeting efficiency. J Mol Biol 2002; 324:577-85. [PMID: 12460562 DOI: 10.1016/s0022-2836(02)01133-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Import of nuclear-encoded proteins into mitochondria and chloroplasts is generally organelle specific and its specificity depends on the N-terminal signal peptide. Yet, a group of proteins known as dual-targeted proteins have a targeting peptide capable of leading the mature protein to both organelles. We have investigated the domain structure of the dual-targeted pea glutathione reductase (GR) signal peptide by using N-terminal truncations. A mutant of the GR precursor (pGR) starting with the second methionine residue of the targeting peptide, pGRdelta2-4, directed import into both organelles, negating the possibility that dual import was controlled by the nature of the N terminus. The deletion of the 30 N-terminal residues (pGRdelta2-30) inhibited import efficiency into chloroplasts substantially and almost completely into mitochondria, whereas the removal of only 16 N-terminal amino acid residues (pGRdelta2-16) resulted in the strongly stimulated mitochondrial import without significantly affecting chloroplast import. Furthermore, N-terminal truncations of the signal peptide (pGRdelta2-16 and pGRdelta2-30) greatly stimulated the mitochondrial processing activity measured with the isolated processing peptidase. These results suggest a domain structure for the dual-targeting peptide of pGR and the existence of domains controlling organellar import efficiency therein.
Collapse
Affiliation(s)
- Charlotta Rudhe
- Department of Biochemistry and Biophysics, Arrhenius Laboratories for Natural Sciences, Stockholm University, S-106 91 Stockholm, Sweden
| | | | | | | |
Collapse
|
49
|
Affiliation(s)
- G A Schuiling
- Division of Human Biology, Faculty of Medical Sciences, University of Groningen, A Deusinglaan 1, 9713 AV Groningen, The Netherlands
| |
Collapse
|
50
|
Bianciotto V, Lumini E, Lanfranco L, Minerdi D, Bonfante P, Perotto S. Detection and identification of bacterial endosymbionts in arbuscular mycorrhizal fungi belonging to the family Gigasporaceae. Appl Environ Microbiol 2000; 66:4503-9. [PMID: 11010905 PMCID: PMC92331 DOI: 10.1128/aem.66.10.4503-4509.2000] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2000] [Accepted: 07/17/2000] [Indexed: 12/11/2022] Open
Abstract
Intracellular bacteria have been found previously in one isolate of the arbuscular mycorrhizal (AM) fungus Gigaspora margarita BEG 34. In this study, we extended our investigation to 11 fungal isolates obtained from different geographic areas and belonging to six different species of the family Gigasporaceae. With the exception of Gigaspora rosea, isolates of all of the AM species harbored bacteria, and their DNA could be PCR amplified with universal bacterial primers. Primers specific for the endosymbiotic bacteria of BEG 34 could also amplify spore DNA from four species. These specific primers were successfully used as probes for in situ hybridization of endobacteria in G. margarita spores. Neighbor-joining analysis of the 16S ribosomal DNA sequences obtained from isolates of Scutellospora persica, Scutellospora castanea, and G. margarita revealed a single, strongly supported branch nested in the genus Burkholderia.
Collapse
Affiliation(s)
- V Bianciotto
- Centro Studio Micologia del Terreno-CNR, 10125 Turin, Italy
| | | | | | | | | | | |
Collapse
|