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Burgess WL, Bishop CD. Bacterial Diversity in Egg Capsular Fluid of the Spotted Salamander Ambystoma maculatum Decreases with Embryonic Development. MICROBIAL ECOLOGY 2023; 86:1789-1798. [PMID: 37148310 DOI: 10.1007/s00248-023-02228-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 04/21/2023] [Indexed: 05/08/2023]
Abstract
Egg capsules within egg masses of the spotted salamander Ambystoma maculatum host a symbiosis with the unicellular green alga Oophila amblystomatis. However, this alga is not the only microbe to inhabit those capsules, and the significance of these additional taxa for the symbiosis is unknown. Spatial and temporal patterns of bacterial diversity in egg capsules of A. maculatum have recently begun to be characterized, but patterns of bacterial diversity as a function of embryonic development are unknown. We sampled fluid from individual capsules in egg masses over a large range of host embryonic development in 2019 and 2020. We used 16S rRNA gene amplicon sequencing to examine how diversity and relative abundance of bacteria changed with embryonic development. In general, bacterial diversity decreased as embryos developed; significant differences were observed (depending on the metric) by embryonic development, pond, and year, and there were interaction effects. The function of bacteria in what is thought of as a bipartite symbiosis calls for further research.
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Affiliation(s)
- William L Burgess
- Department of Biology, St. Francis Xavier University, 2320 Notre Dame Avenue, Antigonish, Nova Scotia, B2G 2W5, Canada
- Current address: Vaccine and Gene Therapy Institute, Oregon Health & Science University, 505 NW 185th Ave, Beaverton, OR, 97006, USA
| | - Cory D Bishop
- Department of Biology, St. Francis Xavier University, 2320 Notre Dame Avenue, Antigonish, Nova Scotia, B2G 2W5, Canada.
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Okabe Y, Matsunaga S. Natural and Artificial Photosymbiosis in Vertebrates. CYTOLOGIA 2022. [DOI: 10.1508/cytologia.87.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Yoji Okabe
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo
| | - Sachihiro Matsunaga
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo
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Bishop C, Jurga E, Graham L. Patterns of bacterial diversity in embryonic capsules of the spotted salamander Ambystoma maculatum: an expanding view of a symbiosis. FEMS Microbiol Ecol 2021; 97:6364358. [PMID: 34482407 DOI: 10.1093/femsec/fiab128] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 09/02/2021] [Indexed: 11/14/2022] Open
Abstract
The unicellular green alga, Oophila amblystomatis, populates egg capsules of the spotted salamander Ambystoma maculatum. This nutrient-exchange mutualism is widely perceived as a bipartite interaction, but the presence and contributing effects of bacteria to this symbiosis are unknown. We used standard cultivation techniques and amplicon sequencing of the V4/V5 region of 16S rRNA gene to identify and compare diversity of bacterial taxa in embryonic capsules with that in the aquatic breeding habitat. Our sampling regime allowed us to investigate diversity among individual capsules of an egg mass and between two ponds and sampling years. Capsules contain much lower diversity of bacteria than pond water, and spatial and temporal variation in intracapsular and pond bacterial diversity was observed. Despite this variation, sequences corresponding to species in the orders Burkholderiales and Oligoflexales were either prevalent or abundant, or both. Isolates most commonly recovered from capsules were closely related to species in the genus Herbaspirillum (Burkholderiaceae); other isolates were pseudomonads, but in all cases are closely related to known vascular plant-associated species. We conclude that, despite observed variation, there are bacterial taxa whose presence is held in common spatially and temporally among capsules and that the symbiosis between O. amblystomatis and A. maculatum may involve these taxa.
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Affiliation(s)
- Cory Bishop
- Department of Biology, St Francis Xavier University, Antigonish, Nova Scotia B2G 2W5, Canada
| | - Emil Jurga
- Department of Molecular Genetics, University of Toronto, 1 King's College Circle Toronto, ON M5S 1A8, Canada
| | - Lori Graham
- Department of Biology, St Francis Xavier University, Antigonish, Nova Scotia B2G 2W5, Canada
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Chávez MN, Moellhoff N, Schenck TL, Egaña JT, Nickelsen J. Photosymbiosis for Biomedical Applications. Front Bioeng Biotechnol 2020; 8:577204. [PMID: 33123516 PMCID: PMC7573207 DOI: 10.3389/fbioe.2020.577204] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 09/10/2020] [Indexed: 12/17/2022] Open
Abstract
Without the sustained provision of adequate levels of oxygen by the cardiovascular system, the tissues of higher animals are incapable of maintaining normal metabolic activity, and hence cannot survive. The consequence of this evolutionarily suboptimal design is that humans are dependent on cardiovascular perfusion, and therefore highly susceptible to alterations in its normal function. However, hope may be at hand. “Photosynthetic strategies,” based on the recognition that photosynthesis is the source of all oxygen, offer a revolutionary and promising solution to pathologies related to tissue hypoxia. These approaches, which have been under development over the past 20 years, seek to harness photosynthetic microorganisms as a local and controllable source of oxygen to circumvent the need for blood perfusion to sustain tissue survival. To date, their applications extend from the in vitro creation of artificial human tissues to the photosynthetic maintenance of oxygen-deprived organs both in vivo and ex vivo, while their potential use in other medical approaches has just begun to be explored. This review provides an overview of the state of the art of photosynthetic technologies and its innovative applications, as well as an expert assessment of the major challenges and how they can be addressed.
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Affiliation(s)
- Myra N Chávez
- Molecular Plant Science, Department Biology I, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Nicholas Moellhoff
- Division of Hand, Plastic and Aesthetic Surgery, University Hospital, Ludwig Maximilian Universität München, Munich, Germany
| | - Thilo L Schenck
- Division of Hand, Plastic and Aesthetic Surgery, University Hospital, Ludwig Maximilian Universität München, Munich, Germany
| | - José Tomás Egaña
- Institute for Biological and Medical Engineering, Schools of Engineering, Biological Sciences and Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jörg Nickelsen
- Molecular Plant Science, Department Biology I, Ludwig-Maximilians-Universität München, Munich, Germany
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D’Errico M, Kennedy C, Hale RE. Egg mass polymorphism in Ambystoma maculatum is not associated with larval performance or survival, or with cell density of the algal symbiont Oophila amblystomatis. Evol Ecol 2020. [DOI: 10.1007/s10682-020-10083-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Nyholm SV. In the beginning: egg-microbe interactions and consequences for animal hosts. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190593. [PMID: 32772674 PMCID: PMC7435154 DOI: 10.1098/rstb.2019.0593] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2020] [Indexed: 12/19/2022] Open
Abstract
Microorganisms are associated with the eggs of many animals. For some hosts, the egg serves as the ideal environment for the vertical transmission of beneficial symbionts between generations, while some bacteria use the egg to parasitize their hosts. In a number of animal groups, egg microbiomes often perform other essential functions. The eggs of aquatic and some terrestrial animals are especially susceptible to fouling and disease since they are exposed to high densities of microorganisms. To overcome this challenge, some hosts form beneficial associations with microorganisms, directly incorporating microbes and/or microbial products on or in their eggs to inhibit pathogens and biofouling. Other functional roles for egg-associated microbiomes are hypothesized to involve oxygen and nutrient acquisition. Although some egg-associated microbiomes are correlated with increased host fitness and are essential for successful development, the mechanisms that lead to such outcomes are often not well understood. This review article will discuss different functions of egg microbiomes and how these associations have influenced the biology and evolution of animal hosts. This article is part of the theme issue 'The role of the microbiome in host evolution'.
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Affiliation(s)
- Spencer V. Nyholm
- Department of Molecular and Cell Biology, University of Connecticut, Storrs, CT 06269USA
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Oophila is monophyletic within a three-taxon eukaryotic microbiome in egg masses of the salamander Ambystoma maculatum. Symbiosis 2020. [DOI: 10.1007/s13199-020-00693-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Small DP, Bishop CD. Physiological benefits and latent effects of an algal-salamander symbiosis. Comp Biochem Physiol A Mol Integr Physiol 2020; 246:110715. [PMID: 32320756 DOI: 10.1016/j.cbpa.2020.110715] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 04/14/2020] [Accepted: 04/15/2020] [Indexed: 11/30/2022]
Abstract
Embryos of the salamander Ambystoma maculatum (Shaw) and the uni-cellular green alga Oophila amblystomatis (Lambert ex Wille) have evolved a resource exchange mutualism. Whereas some of the benefits of the symbiosis to embryos are known, the physiological limitations of the relationship to embryos and carry over or latent effects on larvae are not. To determine the impact of the relationship across life history stages, we measured the growth, survival, and metabolic rate in response to hypoxia of salamander embryos reared under 0-h light (algae absent), 14-h light (control - algae present, fluctuating light conditions) and 24-h light (algae present, chronic light conditions) and the resulting larvae two-weeks post hatch. Embryos reared under 0-h light demonstrated decreased growth and survival compared to 14- and 24-h light, with no effect on metabolic rates or the response of metabolic rates to declining oxygen partial pressure (pO2). Conversely, larvae from embryos reared under 0-h light exhibited compensatory growth during the two-week larval rearing period, with body sizes matching those from the 14-h light treatment. Larvae from embryos reared under 24-h light had lower wet body mass and LT50 values upon starvation compared to those reared under 14-h light. Coupled with the lowest metabolic rates under normoxic pO2 levels, this indicates the presence of negative latent effects. We discuss the findings in relation to the effect of the symbiotic relationship on hypoxia tolerance and larval fitness with respect to the presence of compensatory growth and negative latent effects.
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Affiliation(s)
- Daniel P Small
- Biology Department, St. Francis Xavier University, 2320 Notre Dame Avenue, Antigonish, Nova Scotia B2G 1S7, Canada; Département de Biologie, Chimie et Géographie, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, Québec, G5L 3A1, Canada.
| | - Cory D Bishop
- Biology Department, St. Francis Xavier University, 2320 Notre Dame Avenue, Antigonish, Nova Scotia B2G 1S7, Canada
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Wells MW, Turko AJ, Wright PA. Fish embryos on land: terrestrial embryo deposition lowers oxygen uptake without altering growth or survival in the amphibious fish Kryptolebias marmoratus. ACTA ACUST UNITED AC 2017; 218:3249-56. [PMID: 26491194 DOI: 10.1242/jeb.127399] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Few teleost fishes incubate embryos out of water, but the oxygen-rich terrestrial environment could provide advantages for early growth and development. We tested the hypothesis that embryonic oxygen uptake is limited in aquatic environments relative to air using the self-fertilizing amphibious mangrove rivulus, Kryptolebias marmoratus, which typically inhabits hypoxic, water-filled crab burrows. We found that adult mangrove rivulus released twice as many embryos in terrestrial versus aquatic environments and that air-reared embryos had accelerated developmental rates. Surprisingly, air-reared embryos consumed 44% less oxygen and possessed larger yolk reserves, but attained the same mass, length and chorion thickness. Water-reared embryos moved their opercula ∼2.5 more times per minute compared with air-reared embryos at 7 days post-release, which probably contributed to the higher rates of oxygen uptake and yolk utilization we observed. Genetically identical air- and water-reared embryos from the same parent were raised to maturity, but the embryonic environment did not affect growth, reproduction or emersion ability in adults. Therefore, although aspects of early development were plastic, these early differences were not sustained into adulthood. Kryptolebias marmoratus embryos hatched out of water when exposed to aerial hypoxia. We conclude that exposure to a terrestrial environment reduces the energetic costs of development partly by reducing the necessity of embryonic movements to dispel stagnant boundary layers. Terrestrial incubation of young would be especially beneficial to amphibious fishes that occupy aquatic habitats of poor water quality, assuming low terrestrial predation and desiccation risks.
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Affiliation(s)
- Michael W Wells
- Department of Integrative Biology, University of Guelph, 488 Gordon Street, Guelph, ON, Canada N1G 2W1
| | - Andy J Turko
- Department of Integrative Biology, University of Guelph, 488 Gordon Street, Guelph, ON, Canada N1G 2W1
| | - Patricia A Wright
- Department of Integrative Biology, University of Guelph, 488 Gordon Street, Guelph, ON, Canada N1G 2W1
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Hale RE, Miller N, Francis RA, Kennedy C. Does breeding ecology alter selection on developmental and life history traits? A case study in two Ambystomatid salamanders. Evol Ecol 2016. [DOI: 10.1007/s10682-016-9822-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Kim E, Lin Y, Kerney R, Blumenberg L, Bishop C. Phylogenetic analysis of algal symbionts associated with four North American amphibian egg masses. PLoS One 2014; 9:e108915. [PMID: 25393119 PMCID: PMC4230919 DOI: 10.1371/journal.pone.0108915] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 08/26/2014] [Indexed: 01/17/2023] Open
Abstract
Egg masses of the yellow-spotted salamander Ambystoma maculatum form an association with the green alga “Oophila amblystomatis” (Lambert ex Wille), which, in addition to growing within individual egg capsules, has recently been reported to invade embryonic tissues and cells. The binomial O. amblystomatis refers to the algae that occur in A. maculatum egg capsules, but it is unknown whether this population of symbionts constitutes one or several different algal taxa. Moreover, it is unknown whether egg masses across the geographic range of A. maculatum, or other amphibians, associate with one or multiple algal taxa. To address these questions, we conducted a phylogeographic study of algae sampled from egg capsules of A. maculatum, its allopatric congener A. gracile, and two frogs: Lithobates sylvatica and L. aurora. All of these North American amphibians form associations with algae in their egg capsules. We sampled algae from egg capsules of these four amphibians from localities across North America, established representative algal cultures, and amplified and sequenced a region of 18S rDNA for phylogenetic analysis. Our combined analysis shows that symbiotic algae found in egg masses of four North American amphibians are closely related to each other, and form a well-supported clade that also contains three strains of free-living chlamydomonads. We designate this group as the ‘Oophila’ clade, within which the symbiotic algae are further divided into four distinct subclades. Phylogenies of the host amphibians and their algal symbionts are only partially congruent, suggesting that host-switching and co-speciation both play roles in their associations. We also established conditions for isolating and rearing algal symbionts from amphibian egg capsules, which should facilitate further study of these egg mass specialist algae.
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Affiliation(s)
- Eunsoo Kim
- Division of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York, United States of America
- * E-mail: (CB); (EK)
| | - Yuan Lin
- Department of Biology, St. Francis-Xavier University, Antigonish, Nova Scotia, Canada
| | - Ryan Kerney
- Department of Biology, Gettysburg College, Gettysburg, Pennsylvania, United States of America
| | - Lili Blumenberg
- Division of Invertebrate Zoology and Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, New York, United States of America
| | - Cory Bishop
- Department of Biology, St. Francis-Xavier University, Antigonish, Nova Scotia, Canada
- * E-mail: (CB); (EK)
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The roles of oxygen and ammonia in the symbiotic relationship between the spotted salamander Ambystoma maculatum and the green alga Oophila amblystomatis during embryonic development. Symbiosis 2014. [DOI: 10.1007/s13199-014-0297-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Rodríguez-Gil JL, Brain R, Baxter L, Ruffell S, McConkey B, Solomon K, Hanson M. Optimization of culturing conditions for toxicity testing with the alga Oophila sp. (Chlorophyceae), an amphibian endosymbiont. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2014; 33:2566-2575. [PMID: 25113146 DOI: 10.1002/etc.2711] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 07/19/2014] [Accepted: 08/06/2014] [Indexed: 06/03/2023]
Abstract
Eggs of the yellow-spotted salamander (Ambystoma maculatum) have a symbiotic relationship with green algae. It has been suggested that contaminants that are preferentially toxic to algae, such as herbicides, may impair the symbiont and, hence, indirectly affect the development of the salamander embryo. To enable testing under near-standard conditions for first-tier toxicity screening, the authors isolated the alga from field-collected eggs and identified conditions providing exponential growth rates in the apparent asexual phase of the alga. This approach provided a uniform, single-species culture, facilitating assessment of common toxicity end points and comparison of sensitivity relative to other species. Sequencing of the 18s ribosomal DNA indicated that the isolated alga is closely related to the recently described Oophila amblystomatis but is more similar to other known Chlamydomonas species, suggesting possible biogeographical variability in the genetic identity of the algal symbiont. After a tiered approach to culturing method refinement, a modified Bristol's media with 1 mM NH4 (+) as nitrogen source was found to provide suitable conditions for toxicity testing at 18 °C and 200 µmol m(-2) s(-1) photosynthetically active radiation (PAR) on a 24-h light cycle. The validity of the approach was demonstrated with Zn(2+) as a reference toxicant. Overall, the present study shows that screening for direct effects of contaminants on the algal symbiont without the presence of the host salamander is possible under certain laboratory conditions.
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Affiliation(s)
- José Luis Rodríguez-Gil
- Centre for Toxicology, School of Environmental Sciences, University of Guelph, Guelph, Ontario, Canada
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Graham ER, McKie-Krisberg ZM, Sanders RW. Photosynthetic carbon from algal symbionts peaks during the latter stages of embryonic development in the salamander Ambystoma maculatum. BMC Res Notes 2014; 7:764. [PMID: 25348817 PMCID: PMC4221728 DOI: 10.1186/1756-0500-7-764] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 10/10/2014] [Indexed: 11/25/2022] Open
Abstract
Background It was recently discovered that symbiotic algae in the eggs of the salamander Ambystoma maculatum translocate fixed carbon from photosynthesis to developing embryos. Fixed carbon translocation was shown in embryos at one time point during development, however, it was unknown if fixed carbon translocation occurs throughout all developmental stages. Findings In this study, fixed carbon translocation was measured in salamander eggs at six time points over the latter half of development. Fixed carbon translocation did not occur until the middle tailbud portion of development (stages 26–30), and translocation was measured in 20% or less of eggs sampled. Peak carbon translocation occurred during the late tailbud phase of development (stages 31–35), where as much as 87% of eggs sampled showed translocation, and average percent translocation was 6.5%. During the final stages of development, fixed carbon translocation declined, and translocation was not detected in embryos five days prior to hatching. Conclusions The onset of fixed carbon translocation from Oophila to A. maculatum embryos during the second half of embryonic development is likely due to the corresponding settlement and concentration of Oophila in the inner egg envelope. In addition, carbon translocation ceases in late stage embryos as the inner egg envelope thins and ruptures in preparation for hatching.
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Affiliation(s)
- Erin R Graham
- Department of Biology, Temple University, 1900 N, 12th St,, Philadelphia, PA 19122, USA.
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Baxter L, Brain R, Rodriguez-Gil JL, Hosmer A, Solomon K, Hanson M. Response of the green alga Oophila sp., a salamander endosymbiont, to a PSII-inhibitor under laboratory conditions. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2014; 33:1858-1864. [PMID: 24782078 DOI: 10.1002/etc.2629] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 03/20/2014] [Accepted: 04/28/2014] [Indexed: 06/03/2023]
Abstract
In a rare example of autotroph-vertebrate endosymbiosis, eggs of the yellow-spotted salamander (Ambystoma maculatum) are colonized by a green alga (Oophila sp.) that significantly enhances salamander development. Previous studies have demonstrated the potential for impacts to the salamander embryo when growth of the algae is impaired by exposure to herbicides. To further investigate this relationship, the authors characterized the response of the symbiotic algae (Oophila sp.) alone to the photosystem II (PSII) inhibitor atrazine under controlled laboratory conditions. After extraction of the alga from A. maculatum eggs and optimization of culturing conditions, 4 toxicity assays (96 h each) were conducted. Recovery of the algal population was also assessed after a further 96 h in untreated media. Average median effective concentration (EC50) values of 123 µg L(-1) (PSII yield), 169 µg L(-1) (optical density), and 299 µg L(-1) (growth rate) were obtained after the 96-h exposure. Full recovery of exposed algal populations after 96 h in untreated media was observed for all endpoints, except for optical density at the greatest concentration tested (300 µg L(-1) ). Our results show that, under laboratory conditions, Oophila sp. is generally less sensitive to atrazine than standard test species. Although conditions of growth in standard toxicity tests are not identical to those in the natural environment, these results provide an understanding of the tolerance of this alga to PSII inhibitors as compared with other species.
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Affiliation(s)
- Leilan Baxter
- Centre for Toxicology, University of Guelph, Guelph, Ontario, Canada
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Dynamics of the growth, life history transformation and photosynthetic capacity of Oophila amblystomatis (Chlorophyceae), a green algal symbiont associated with embryos of the northeastern yellow spotted salamander Ambystoma maculatum (Amphibia). Symbiosis 2014. [DOI: 10.1007/s13199-014-0287-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Graham ER, Fay SA, Davey A, Sanders RW. Intracapsular algae provide fixed carbon to developing embryos of the salamander Ambystoma maculatum. ACTA ACUST UNITED AC 2012; 216:452-9. [PMID: 23038736 DOI: 10.1242/jeb.076711] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Each spring, North American spotted salamander (Ambystoma maculatum) females each lay hundreds of eggs in shallow pools of water. Eggs are surrounded by jelly layers and are deposited as large gelatinous masses. Following deposition, masses are penetrated by a mutualistic green alga, Oophila amblystomatis, which enters individual egg capsules, proliferates and aggregates near the salamander embryo, providing oxygen that enhances development. We examined the effects of population density of intracapsular O. amblystomatis on A. maculatum embryos and show that larger algal populations promote faster embryonic growth and development. Also, we show that carbon fixed by O. amblystomatis is transferred to the embryos, providing the first evidence of direct translocation of photosynthate from a symbiont to a vertebrate host.
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Affiliation(s)
- Erin R Graham
- Department of Biology, Temple University, Philadelphia, PA 19122, USA.
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Bianchini K, Tattersall GJ, Sashaw J, Porteus CS, Wright PA. Acid water interferes with salamander-green algae symbiosis during early embryonic development. Physiol Biochem Zool 2012; 85:470-80. [PMID: 22902375 DOI: 10.1086/667407] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The inner egg capsule of embryos of the yellow-spotted salamander (Ambystoma maculatum) are routinely colonized by green algae, such as Oophila amblystomatis, that supply O(2) in the presence of light and may consume nitrogenous wastes, forming what has been proposed to be a mutualistic relationship. Given that A. maculatum have been reported to breed in acidic (pH <5.0) and neutral lakes, we hypothesized that low water pH would negatively affect these symbiotic organisms and alter the gradients within the jelly mass. Oxygen gradients were detected within jelly masses measured directly in a natural breeding pond (pH 4.5-4.8) at midday in full sunlight. In the lab, embryo jelly masses reared continuously at pH 4.5 had lower P(O)₂and higher ammonia levels relative to jelly masses held at pH 8.0 (control). Ammonia and lactate concentrations in embryonic tissues were approximately 37%-93% higher, respectively, in embryos reared at water pH 4.5 compared with pH 8.0. Mass was also reduced in embryos reared at pH 4.5 versus pH 8.0. In addition, light conditions (24 h light, 12L : 12D, or 24 h dark) and embryonic position (periphery vs. center) in the jelly mass affected P(O)₂but not ammonia gradients, suggesting that algal symbionts generate O(2) but do not significantly impact local ammonia concentrations, regardless of the pH of the water. We conclude that chronic exposure to acidic breeding ponds had a profound effect on the microenvironment of developing A. maculatum embryos, which in turn resulted in an elevation of potentially harmful metabolic end products and inhibited growth. Under acidic conditions, the expected benefit provided by the algae to the salamander embryo (i.e., high O(2) and low ammonia microenvironment) is compromised, suggesting that the A. maculatum-algal mutualism is beneficial to salamanders only at higher water pH values.
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Affiliation(s)
- Kristin Bianchini
- Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada.
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Abstract
Background The evolution of eukaryotic cells is widely agreed to have proceeded through a series of endosymbiotic events between larger cells and proteobacteria or cyanobacteria, leading to the formation of mitochondria or chloroplasts, respectively. Engineered endosymbiotic relationships between different species of cells are a valuable tool for synthetic biology, where engineered pathways based on two species could take advantage of the unique abilities of each mutualistic partner. Results We explored the possibility of using the photosynthetic bacterium Synechococcus elongatus PCC 7942 as a platform for studying evolutionary dynamics and for designing two-species synthetic biological systems. We observed that the cyanobacteria were relatively harmless to eukaryotic host cells compared to Escherichia coli when injected into the embryos of zebrafish, Danio rerio, or taken up by mammalian macrophages. In addition, when engineered with invasin from Yersinia pestis and listeriolysin O from Listeria monocytogenes, S. elongatus was able to invade cultured mammalian cells and divide inside macrophages. Conclusion Our results show that it is possible to engineer photosynthetic bacteria to invade the cytoplasm of mammalian cells for further engineering and applications in synthetic biology. Engineered invasive but non-pathogenic or immunogenic photosynthetic bacteria have great potential as synthetic biological devices.
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Abstract
The association between embryos of the spotted salamander (Ambystoma maculatum) and green algae ("Oophila amblystomatis" Lamber ex Printz) has been considered an ectosymbiotic mutualism. We show here, however, that this symbiosis is more intimate than previously reported. A combination of imaging and algal 18S rDNA amplification reveals algal invasion of embryonic salamander tissues and cells during development. Algal cells are detectable from embryonic and larval Stages 26-44 through chlorophyll autofluorescence and algal 18S rDNA amplification. Algal cell ultrastructure indicates both degradation and putative encystment during the process of tissue and cellular invasion. Fewer algal cells were detected in later-stage larvae through FISH, suggesting that the decline in autofluorescent cells is primarily due to algal cell death within the host. However, early embryonic egg capsules also contained encysted algal cells on the inner capsule wall, and algal 18S rDNA was amplified from adult reproductive tracts, consistent with oviductal transmission of algae from one salamander generation to the next. The invasion of algae into salamander host tissues and cells represents a unique association between a vertebrate and a eukaryotic alga, with implications for research into cell-cell recognition, possible exchange of metabolites or DNA, and potential congruence between host and symbiont population structures.
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Conspecific presence affects the physiology and behaviour of developing trout. Physiol Behav 2010; 99:599-604. [DOI: 10.1016/j.physbeh.2010.01.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2009] [Revised: 01/12/2010] [Accepted: 01/21/2010] [Indexed: 11/23/2022]
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