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Rose MM, Scheer D, Hou Y, Hotter VS, Komor AJ, Aiyar P, Scherlach K, Vergara F, Yan Q, Loper JE, Jakob T, van Dam NM, Hertweck C, Mittag M, Sasso S. The bacterium Pseudomonas protegens antagonizes the microalga Chlamydomonas reinhardtii using a blend of toxins. Environ Microbiol 2021; 23:5525-5540. [PMID: 34347373 DOI: 10.1111/1462-2920.15700] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 06/24/2021] [Accepted: 07/31/2021] [Indexed: 11/27/2022]
Abstract
The unicellular alga Chlamydomonas reinhardtii and the bacterium Pseudomonas protegens serve as a model to study the interactions between photosynthetic and heterotrophic microorganisms. P. protegens secretes the cyclic lipopeptide orfamide A that interferes with cytosolic Ca2+ homeostasis in C. reinhardtii resulting in deflagellation of the algal cells. Here, we studied the roles of additional secondary metabolites secreted by P. protegens using individual compounds and co-cultivation of algae with bacterial mutants. Rhizoxin S2, pyrrolnitrin, pyoluteorin, 2,4-diacetylphloroglucinol (DAPG) and orfamide A all induce changes in cell morphology and inhibit the growth of C. reinhardtii. Rhizoxin S2 exerts the strongest growth inhibition, and its action depends on the spatial structure of the environment (agar versus liquid culture). Algal motility is unaffected by rhizoxin S2 and is most potently inhibited by orfamide A (IC50 = 4.1 μM). Pyrrolnitrin and pyoluteorin both interfere with algal cytosolic Ca2+ homeostasis and motility whereas high concentrations of DAPG immobilize C. reinhardtii without deflagellation or disturbance of Ca2+ homeostasis. Co-cultivation with a regulatory mutant of bacterial secondary metabolism (ΔgacA) promotes algal growth under spatially structured conditions. Our results reveal how a single soil bacterium uses an arsenal of secreted antialgal compounds with complementary and partially overlapping activities.
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Affiliation(s)
- Magdalena M Rose
- Institute of Biology, Leipzig University, Leipzig, Germany.,Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena, Germany
| | - Daniel Scheer
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena, Germany
| | - Yu Hou
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena, Germany
| | - Vivien S Hotter
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena, Germany
| | - Anna J Komor
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Jena, Germany
| | - Prasad Aiyar
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena, Germany
| | - Kirstin Scherlach
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Jena, Germany
| | - Fredd Vergara
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.,Institute of Biodiversity, Friedrich Schiller University Jena, Jena, Germany
| | - Qing Yan
- Department of Plant Sciences and Plant Pathology, Montana State University, Bozeman, Montana, USA
| | - Joyce E Loper
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
| | - Torsten Jakob
- Institute of Biology, Leipzig University, Leipzig, Germany
| | - Nicole M van Dam
- German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany.,Institute of Biodiversity, Friedrich Schiller University Jena, Jena, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Jena, Germany.,Faculty of Biological Sciences, Friedrich Schiller University Jena, Jena, Germany
| | - Maria Mittag
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena, Germany
| | - Severin Sasso
- Institute of Biology, Leipzig University, Leipzig, Germany.,Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich Schiller University Jena, Jena, Germany.,German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, Leipzig, Germany
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2
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Hamid ME, Reitz T, Joseph MRP, Hommel K, Mahgoub A, Elhassan MM, Buscot F, Tarkka M. Diversity and geographic distribution of soil streptomycetes with antagonistic potential against actinomycetoma-causing Streptomyces sudanensis in Sudan and South Sudan. BMC Microbiol 2020; 20:33. [PMID: 32050891 PMCID: PMC7017484 DOI: 10.1186/s12866-020-1717-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 01/30/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Production of antibiotics to inhibit competitors affects soil microbial community composition and contributes to disease suppression. In this work, we characterized whether Streptomyces bacteria, prolific antibiotics producers, inhibit a soil borne human pathogenic microorganism, Streptomyces sudanensis. S. sudanensis represents the major causal agent of actinomycetoma - a largely under-studied and dreadful subcutaneous disease of humans in the tropics and subtropics. The objective of this study was to evaluate the in vitro S. sudanensis inhibitory potential of soil streptomycetes isolated from different sites in Sudan, including areas with frequent (mycetoma belt) and rare actinomycetoma cases of illness. RESULTS Using selective media, 173 Streptomyces isolates were recovered from 17 sites representing three ecoregions and different vegetation and ecological subdivisions in Sudan. In total, 115 strains of the 173 (66.5%) displayed antagonism against S. sudanensis with different levels of inhibition. Strains isolated from the South Saharan steppe and woodlands ecoregion (Northern Sudan) exhibited higher inhibitory potential than those strains isolated from the East Sudanian savanna ecoregion located in the south and southeastern Sudan, or the strains isolated from the Sahelian Acacia savanna ecoregion located in central and western Sudan. According to 16S rRNA gene sequence analysis, isolates were predominantly related to Streptomyces werraensis, S. enissocaesilis, S. griseostramineus and S. prasinosporus. Three clusters of isolates were related to strains that have previously been isolated from human and animal actinomycetoma cases: SD524 (Streptomyces sp. subclade 6), SD528 (Streptomyces griseostramineus) and SD552 (Streptomyces werraensis). CONCLUSION The in vitro inhibitory potential against S. sudanensis was proven for more than half of the soil streptomycetes isolates in this study and this potential may contribute to suppressing the abundance and virulence of S. sudanensis. The streptomycetes isolated from the mycetoma free South Saharan steppe ecoregion show the highest average inhibitory potential. Further analyses suggest that mainly soil properties and rainfall modulate the structure and function of Streptomyces species, including their antagonistic activity against S. sudanensis.
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Affiliation(s)
- Mohamed E Hamid
- Department of Soil Ecology, Helmholtz-Centre for Environmental Research GmbH - UFZ, Theodor-Lieser-Str. 4, 06120, Halle, Germany
- Department of Clinical Microbiology and Parasitology/ College of Medicine, King Khalid University, PO Box 641, Abha, 61314, Saudi Arabia
- Department of Preventive Medicine, Faculty of Veterinary Science, University of Khartoum, Khartoum, Sudan
| | - Thomas Reitz
- Department of Soil Ecology, Helmholtz-Centre for Environmental Research GmbH - UFZ, Theodor-Lieser-Str. 4, 06120, Halle, Germany
- German Centre of Integrative Biodiversity Research (iDiv), Halle - Jena - Leipzig, Germany
| | - Martin R P Joseph
- Department of Clinical Microbiology and Parasitology/ College of Medicine, King Khalid University, PO Box 641, Abha, 61314, Saudi Arabia
| | - Kerstin Hommel
- Department of Soil Ecology, Helmholtz-Centre for Environmental Research GmbH - UFZ, Theodor-Lieser-Str. 4, 06120, Halle, Germany
| | - Adil Mahgoub
- Department of Preventive Medicine, Faculty of Veterinary Science, University of Khartoum, Khartoum, Sudan
| | - Mogahid M Elhassan
- Department of Clinical Laboratory Science, College of Applied Medical Science, Taibah University, Medina, Saudi Arabia
| | - François Buscot
- Department of Soil Ecology, Helmholtz-Centre for Environmental Research GmbH - UFZ, Theodor-Lieser-Str. 4, 06120, Halle, Germany
- German Centre of Integrative Biodiversity Research (iDiv), Halle - Jena - Leipzig, Germany
| | - Mika Tarkka
- Department of Soil Ecology, Helmholtz-Centre for Environmental Research GmbH - UFZ, Theodor-Lieser-Str. 4, 06120, Halle, Germany.
- German Centre of Integrative Biodiversity Research (iDiv), Halle - Jena - Leipzig, Germany.
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Westhoff S, Otto SB, Swinkels A, Bode B, van Wezel GP, Rozen DE. Spatial structure increases the benefits of antibiotic production in Streptomyces. Evolution 2019; 74:179-187. [PMID: 31393002 PMCID: PMC6973283 DOI: 10.1111/evo.13817] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 06/28/2019] [Accepted: 07/02/2019] [Indexed: 12/17/2022]
Abstract
Bacteria in the soil compete for limited resources. One of the ways they might do this is by producing antibiotics, but the metabolic costs of antibiotics and their low concentrations have caused uncertainty about the ecological role of these products for the bacteria that produce them. Here, we examine the benefits of streptomycin production by the filamentous bacterium Streptomyces griseus. We first provide evidence that streptomycin production enables S. griseus to kill and invade the susceptible species, S. coelicolor, but not a streptomycin‐resistant mutant of this species. Next, we show that the benefits of streptomycin production are density dependent, because production scales positively with cell number, and frequency dependent, with a threshold of invasion of S. griseus at around 1%. Finally, using serial transfer experiments where spatial structure is either maintained or destroyed, we show that spatial structure reduces the threshold frequency of invasion by more than 100‐fold, indicating that antibiotic production can permit invasion from extreme rarity. Our results show that streptomycin is both an offensive and defensive weapon that facilitates invasion into occupied habitats and also protects against invasion by competitors. They also indicate that the benefits of antibiotic production rely on ecological interactions occurring at small local scales.
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Affiliation(s)
- Sanne Westhoff
- Institute of Biology, Leiden University, Sylviusweg 72, 2333, BE, Leiden, The Netherlands
| | - Simon B Otto
- Institute of Biology, Leiden University, Sylviusweg 72, 2333, BE, Leiden, The Netherlands
| | - Aram Swinkels
- Institute of Biology, Leiden University, Sylviusweg 72, 2333, BE, Leiden, The Netherlands
| | - Bo Bode
- Institute of Biology, Leiden University, Sylviusweg 72, 2333, BE, Leiden, The Netherlands
| | - Gilles P van Wezel
- Institute of Biology, Leiden University, Sylviusweg 72, 2333, BE, Leiden, The Netherlands
| | - Daniel E Rozen
- Institute of Biology, Leiden University, Sylviusweg 72, 2333, BE, Leiden, The Netherlands
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Kosakowski J, Verma P, Sengupta S, Higgs PG. The evolution of antibiotic production rate in a spatial model of bacterial competition. PLoS One 2018; 13:e0205202. [PMID: 30379843 PMCID: PMC6209167 DOI: 10.1371/journal.pone.0205202] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 09/20/2018] [Indexed: 11/18/2022] Open
Abstract
We consider competition between antibiotic producing bacteria, non-producers (or cheaters), and sensitive cells in a two-dimensional lattice model. Previous work has shown that these three cell types can survive in spatial models due to the presence of spatial patterns, whereas coexistence is not possible in a well-mixed system. We extend this to consider the evolution of the antibiotic production rate, assuming that the cost of antibiotic production leads to a reduction in growth rate of the producers. We find that coexistence occurs for an intermediate range of antibiotic production rate. If production rate is too high or too low, only sensitive cells survive. When evolution of production rate is allowed, a mixture of cell types arises in which there is a dominant producer strain that produces sufficient to limit the growth of sensitive cells and which is able to withstand the presence of cheaters in its own species. The mixture includes a range of low-rate producers and non-producers, none of which could survive without the presence of the dominant producer strain. We also consider the case of evolution of antibiotic resistance within the sensitive species. In order for the resistant cells to survive, they must grow faster than both the non-producers and the producers. However, if the resistant cells grow too rapidly, the producing species is eliminated, after which the resistance mutation is no longer useful, and sensitive cells take over the system. We show that there is a range of growth rates of the resistant cells where the two species coexist, and where the production mechanism is maintained as a polymorphism in the producing species and the resistance mechanism is maintained as a polymorphism in the sensitive species.
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Affiliation(s)
- Jakub Kosakowski
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Prateek Verma
- Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Supratim Sengupta
- Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, India
| | - Paul G. Higgs
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
- * E-mail:
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Ruxton GD, Wilkinson DM, Schaefer HM, Sherratt TN. Why fruit rots: theoretical support for Janzen's theory of microbe-macrobe competition. Proc Biol Sci 2014; 281:20133320. [PMID: 24619444 DOI: 10.1098/rspb.2013.3320] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We present a formal model of Janzen's influential theory that competition for resources between microbes and vertebrates causes microbes to be selected to make these resources unpalatable to vertebrates. That is, fruit rots, seeds mould and meat spoils, in part, because microbes gain a selective advantage if they can alter the properties of these resources to avoid losing the resources to vertebrate consumers. A previous model had failed to find circumstances in which such a costly spoilage trait could flourish; here, we present a simple analytic model of a general situation where costly microbial spoilage is selected and persists. We argue that the key difference between the two models lies in their treatments of microbial dispersal. If microbial dispersal is sufficiently spatially constrained that different resource items can have differing microbial communities, then spoilage will be selected; however, if microbial dispersal has a strong homogenizing effect on the microbial community then spoilage will not be selected. We suspect that both regimes will exist in the natural world, and suggest how future empirical studies could explore the influence of microbial dispersal on spoilage.
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Affiliation(s)
- Graeme D Ruxton
- School of Biology, University of St Andrews, , St Andrews KY16 9TH, UK, Biology and Earth sciences, Liverpool John Moores University, , Liverpool L3 3AF, UK, Department of Evolutionary Biology and Animal Ecology, Faculty of Biology, University of Freiburg, , Hauptstrasse 1, Freiburg 79104, Germany, Department of Biology, Carleton University, , Ottawa, Ontario, Canada , K1S 5B6
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Gama JA, Reis AM, Domingues I, Mendes-Soares H, Matos AM, Dionisio F. Temperate bacterial viruses as double-edged swords in bacterial warfare. PLoS One 2013; 8:e59043. [PMID: 23536852 PMCID: PMC3594171 DOI: 10.1371/journal.pone.0059043] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 02/11/2013] [Indexed: 11/29/2022] Open
Abstract
It has been argued that bacterial cells may use their temperate viruses as biological weapons. For instance, a few bacterial cells among a population of lysogenic cells could release the virus and kill susceptible non-lysogenic competitors, while their clone mates would be immune. Because viruses replicate inside their victims upon infection, this process would amplify their number in the arena. Sometimes, however, temperate viruses spare recipient cells from death by establishing themselves in a dormant state inside cells. This phenomenon is called lysogenization and, for some viruses such as the λ virus, the probability of lysogenization increases with the multiplicity of infection. Therefore, the amplification of viruses leads to conflicting predictions about the efficacy of temperate viruses as biological weapons: amplification can increase the relative advantage of clone mates of lysogens but also the likelihood of saving susceptible cells from death, because the probability of lysogenization is higher. To test the usefulness of viruses as biological weapons, we performed competition experiments between lysogenic Escherichia coli cells carrying the λ virus and susceptible λ-free E. coli cells, either in a structured or unstructured habitat. In structured and sometimes in unstructured habitats, the λ virus qualitatively behaved as a "replicating toxin". However, such toxic effect of λ viruses ceased after a few days of competition. This was due to the fact that many of initially susceptible cells became lysogenic. Massive lysogenization of susceptible cells occurred precisely under the conditions where the amplification of the virus was substantial. From then on, these cells and their descendants became immune to the λ virus. In conclusion, if at short term bacterial cells may use temperate viruses as biological weapons, after a few days only the classical view of temperate bacterial viruses as parasitic agents prevails.
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Affiliation(s)
- João Alves Gama
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Centro de Biologia Ambiental, Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
| | - Ana Maria Reis
- Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
- Center for Biodiversity, Functional and Integrative Genomics, Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
| | - Iolanda Domingues
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Centro de Biologia Ambiental, Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
| | - Helena Mendes-Soares
- Department of Biological Sciences and the Institute for Bioinformatics and Evolutionary Studies, University of Idaho, Moscow, Idaho, United States of America
| | - Ana Margarida Matos
- Center for Biodiversity, Functional and Integrative Genomics, Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
| | - Francisco Dionisio
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- Centro de Biologia Ambiental, Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
- Departamento de Biologia Vegetal, Faculdade de Ciências da Universidade de Lisboa, Lisboa, Portugal
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Dechesne A, Or D, Smets BF. Limited diffusive fluxes of substrate facilitate coexistence of two competing bacterial strains. FEMS Microbiol Ecol 2008; 64:1-8. [PMID: 18312376 DOI: 10.1111/j.1574-6941.2008.00446.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Soils are known to support a great bacterial diversity down to the millimeter scale, but the mechanisms by which such a large diversity is sustained are largely unknown. A feature of unsaturated soils is that water usually forms thin, poorly-connected films, which limit solute diffusive fluxes. It has been proposed, but never unambiguously experimentally tested, that a low substrate diffusive flux would impact bacterial diversity, by promoting the coexistence between slow-growing bacteria and their potentially faster-growing competitors. We used a simple experimental system, based on a Petri dish and a perforated Teflon membrane to control diffusive fluxes of substrate (benzoate) whilst permitting direct observation of bacterial colonies. The system was inoculated with prescribed strains of Pseudomonas, whose growth was quantified by microscopic monitoring of the fluorescent proteins they produced. We observed that substrate diffusion limitation reduced the growth rate of the otherwise fast-growing Pseudomonas putida KT2440 strain. This strain out-competed Pseudomonas fluorescens F113 in liquid culture, but its competitive advantage was less marked on solid media, and even disappeared under conditions of low substrate diffusion. Low diffusive fluxes of substrate, characteristic of many unsaturated media (e.g. soils, food products), can thus promote bacterial coexistence in a competitive situation between two strains. This mechanism might therefore contribute to maintaining the noncompetitive diversity pattern observed in unsaturated soils.
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Affiliation(s)
- Arnaud Dechesne
- Institute of Environment and Resources DTU, Technical University of Denmark Lyngby, Denmark.
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Secondary Metabolites of Soil Streptomycetes in Biotic Interactions. SECONDARY METABOLITES IN SOIL ECOLOGY 2008. [DOI: 10.1007/978-3-540-74543-3_6] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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10
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Abstract
The ability of rare types to invade populations is important for the maintenance of diversity and spread of beneficial variants. Spatial structure promotes strategies of interference competition by limiting diffusion of interference toxins and resources, often allowing interference competitors to invade when rare. Consistent with previous results in other microbial systems, toxin production by Saccharomyces cerevisiae is advantageous in spatially structured, high-density environments, but not in unstructured environments. However, at low density and at low frequency, rare toxin producers cannot invade populations of common, sensitive, toxin nonproducers. This is because the likelihood of interaction between toxin producers and sensitives depends upon the density and frequency of both competitors.
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Affiliation(s)
- Duncan Greig
- Department of Biology, University College London, Wolfson House, 4 Stephenson Way, London NW1 2HE, United Kingdom.
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12
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Davelos AL, Kinkel LL, Samac DA. Spatial variation in frequency and intensity of antibiotic interactions among Streptomycetes from prairie soil. Appl Environ Microbiol 2004; 70:1051-8. [PMID: 14766588 PMCID: PMC348876 DOI: 10.1128/aem.70.2.1051-1058.2004] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2003] [Accepted: 11/03/2003] [Indexed: 11/20/2022] Open
Abstract
Antibiotic interactions are believed to be significant to microbial fitness in soil, yet little is known of the frequency, intensity, and diversity of antibiotic inhibition and resistance among indigenous microbes. To begin to address these issues, we studied the abilities of streptomycete isolates from prairie soil to inhibit growth and display resistance to antibiotics produced by a test collection of 10 streptomycete isolates. Wide variations in antibiotic inhibition and resistance for prairie isolates among three locations and four soil depths within a 1-m2 plot were revealed. Fewer than 10% of 153 prairie isolates inhibited all 10 test isolates, while more than 40% of the isolates did not inhibit any of the test isolates. No field isolate was resistant to all of the test isolates, nor was any isolate susceptible to all of the test isolates. No correlation between inhibition and resistance phenotypes was found, suggesting that inhibition and resistance are under independent selection. The significant spatial variation in the frequency and intensity of antibiotic inhibition implies that the fitness benefits of antibiotic production are not the same among locations in soil. In contrast, the consistency of resistance over space indicates that its significance to fitness across locations is stable or the costs of maintaining resistance in the absence of selection are small or nonexistent. The spatial clustering of antibiotic inhibitory activity suggests a variable matrix of selection pressures and microbial responses across the soil landscape.
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Affiliation(s)
- Anita L Davelos
- Department of Plant Pathology. Plant Science Research Unit, Agricultural Research Service, U.S. Department of Agriculture, St. Paul, Minnesota 55108, USA.
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