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Davidson MJ, Bushell R, Ploeg R, Marenda M, Halliday C, Goodall D, Gilbert D, Kosch TA, Skerratt LF, Berger L. Embryo mortality in a captive-bred, Critically Endangered amphibian. DISEASES OF AQUATIC ORGANISMS 2022; 152:73-83. [PMID: 36453456 DOI: 10.3354/dao03706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
The Critically Endangered southern corroboree frog Pseudophryne corroboree is dependent upon captive assurance colonies for its continued survival. Although the captive breeding programme for this species has largely been successful, embryonic mortality remains high (40-90% per year). This study aimed to investigate the causes of mortality in P. corroboree embryos in the captive collection at Melbourne Zoo. During the 2021 breeding season, we investigated 108 abnormal embryos to determine the impact of infections and anatomical deformities on survival and used culture and molecular methods to identify microbes. Overall, 100% of abnormal embryos had fungal infections, and of these, 41.6% also had anatomical deformities. The mortality rate in abnormal embryos was 89.8%; however, we detected no difference in survival in any of the 3 observed fungal growth patterns or between deformed and non-deformed embryos. Sanger sequencing of the ITS region identified fungal isolates belonging to the genus Ilyonectria, the first record in a vertebrate host, and another as a Plectosphaerella sp., which is the first record of infection in an embryo. Dominant bacteria identified were of the genera Herbaspirillum and Flavobacterium; however, their role in the mortality is unknown. Fungal infection and deformities have a significant impact on embryo survival in captive-bred P. corroboree. In a species which relies on captive breeding, identifying and reducing the impacts of embryonic mortality can inform conservation efforts and improve reintroduction outcomes.
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Affiliation(s)
- M J Davidson
- Faculty of Veterinary and Agricultural Science, University of Melbourne, Werribee, Victoria 3030, Australia
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2
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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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Anslan S, Sachs M, Rancilhac L, Brinkmann H, Petersen J, Künzel S, Schwarz A, Arndt H, Kerney R, Vences M. Diversity and substrate-specificity of green algae and other micro-eukaryotes colonizing amphibian clutches in Germany, revealed by DNA metabarcoding. Naturwissenschaften 2021; 108:29. [PMID: 34181110 PMCID: PMC8238718 DOI: 10.1007/s00114-021-01734-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 03/20/2021] [Accepted: 05/02/2021] [Indexed: 02/17/2023]
Abstract
Amphibian clutches are colonized by diverse but poorly studied communities of micro-organisms. One of the most noted ones is the unicellular green alga, Oophila amblystomatis, but the occurrence and role of other micro-organisms in the capsular chamber surrounding amphibian clutches have remained largely unstudied. Here, we undertook a multi-marker DNA metabarcoding study to characterize the community of algae and other micro-eukaryotes associated with agile frog (Rana dalmatina) clutches. Samplings were performed at three small ponds in Germany, from four substrates: water, sediment, tree leaves from the bottom of the pond, and R. dalmatina clutches. Sampling substrate strongly determined the community compositions of algae and other micro-eukaryotes. Therefore, as expected, the frog clutch-associated communities formed clearly distinct clusters. Clutch-associated communities in our study were structured by a plethora of not only green algae, but also diatoms and other ochrophytes. The most abundant operational taxonomic units (OTUs) in clutch samples were taxa from Chlamydomonas, Oophila, but also from Nitzschia and other ochrophytes. Sequences of Oophila "Clade B" were found exclusively in clutches. Based on additional phylogenetic analyses of 18S rDNA and of a matrix of 18 nuclear genes derived from transcriptomes, we confirmed in our samples the existence of two distinct clades of green algae assigned to Oophila in past studies. We hypothesize that "Clade B" algae correspond to the true Oophila, whereas "Clade A" algae are a series of Chlorococcum species that, along with other green algae, ochrophytes and protists, colonize amphibian clutches opportunistically and are often cultured from clutch samples due to their robust growth performance. The clutch-associated communities were subject to filtering by sampling location, suggesting that the taxa colonizing amphibian clutches can drastically differ depending on environmental conditions.
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Affiliation(s)
- Sten Anslan
- Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany.
| | - Maria Sachs
- Institute of Zoology, University of Cologne, Zülpicherstr. 47b, 50674, Köln, Germany
| | - Lois Rancilhac
- Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
| | - Henner Brinkmann
- Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Jörn Petersen
- Leibniz Institute DSMZ - German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Sven Künzel
- Department of Evolutionary Genetics, Max Planck Institute for Evolutionary Biology, 24306, Plön, Germany
| | - Anja Schwarz
- Institute of Geosystems and Bioindication, Technische Universität Braunschweig, Braunschweig, Germany
| | - Hartmut Arndt
- Institute of Zoology, University of Cologne, Zülpicherstr. 47b, 50674, Köln, Germany
| | - Ryan Kerney
- Department of Biology, Gettysburg College, Gettysburg, PA, USA
| | - Miguel Vences
- Zoological Institute, Technische Universität Braunschweig, Braunschweig, Germany
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Burns JA, Kerney R, Duhamel S. Heterotrophic Carbon Fixation in a Salamander-Alga Symbiosis. Front Microbiol 2020; 11:1815. [PMID: 32849422 PMCID: PMC7417444 DOI: 10.3389/fmicb.2020.01815] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 07/10/2020] [Indexed: 12/14/2022] Open
Abstract
The unique symbiosis between a vertebrate salamander, Ambystoma maculatum, and unicellular green alga, Oophila amblystomatis, involves multiple modes of interaction. These include an ectosymbiotic interaction where the alga colonizes the egg capsule, and an intracellular interaction where the alga enters tissues and cells of the salamander. One common interaction in mutualist photosymbioses is the transfer of photosynthate from the algal symbiont to the host animal. In the A. maculatum-O. amblystomatis interaction, there is conflicting evidence regarding whether the algae in the egg capsule transfer chemical energy captured during photosynthesis to the developing salamander embryo. In experiments where we took care to separate the carbon fixation contributions of the salamander embryo and algal symbionts, we show that inorganic carbon fixed by A. maculatum embryos reaches 2% of the inorganic carbon fixed by O. amblystomatis algae within an egg capsule after 2 h in the light. After 2 h in the dark, inorganic carbon fixed by A. maculatum embryos is 800% of the carbon fixed by O. amblystomatis algae within an egg capsule. Using photosynthesis inhibitors, we show that A. maculatum embryos and O. amblystomatis algae compete for available inorganic carbon within the egg capsule environment. Our results confirm earlier studies suggesting a role of heterotrophic carbon fixation during vertebrate embryonic development. Our results also show that the considerable capacity of developing A. maculatum embryos for inorganic carbon fixation precludes our ability to distinguish any minor role of photosynthetically transferred carbon from algal symbionts to host salamanders using bicarbonate introduced to the egg system as a marker.
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Affiliation(s)
- John A. Burns
- Division of Biology and Paleo Environment, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY, United States
- Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, United States
| | - Ryan Kerney
- Department of Biology, Gettysburg College, Gettysburg, PA, United States
| | - Solange Duhamel
- Division of Biology and Paleo Environment, Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY, United States
- Department of Molecular and Cellular Biology, The University of Arizona, Tucson, AZ, United States
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5
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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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Kerney R, Leavitt J, Hill E, Zhang H, Kim E, Burns J. Co-cultures of Oophila amblystomatis between Ambystoma maculatum and Ambystoma gracile hosts show host-symbiont fidelity. Symbiosis 2019. [DOI: 10.1007/s13199-018-00591-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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8
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Burns JA, Zhang H, Hill E, Kim E, Kerney R. Transcriptome analysis illuminates the nature of the intracellular interaction in a vertebrate-algal symbiosis. eLife 2017; 6:e22054. [PMID: 28462779 PMCID: PMC5413350 DOI: 10.7554/elife.22054] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 03/15/2017] [Indexed: 12/19/2022] Open
Abstract
During embryonic development, cells of the green alga Oophila amblystomatis enter cells of the salamander Ambystoma maculatum forming an endosymbiosis. Here, using de novo dual-RNA seq, we compared the host salamander cells that harbored intracellular algae to those without algae and the algae inside the animal cells to those in the egg capsule. This two-by-two-way analysis revealed that intracellular algae exhibit hallmarks of cellular stress and undergo a striking metabolic shift from oxidative metabolism to fermentation. Culturing experiments with the alga showed that host glutamine may be utilized by the algal endosymbiont as a primary nitrogen source. Transcriptional changes in salamander cells suggest an innate immune response to the alga, with potential attenuation of NF-κB, and metabolic alterations indicative of modulation of insulin sensitivity. In stark contrast to its algal endosymbiont, the salamander cells did not exhibit major stress responses, suggesting that the host cell experience is neutral or beneficial.
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Affiliation(s)
- John A Burns
- Division of Invertebrate Zoology, American Museum of Natural History, New York, United States
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, United States
| | - Huanjia Zhang
- Department of Biology, Gettysburg College, Gettysburg, United States
| | - Elizabeth Hill
- Department of Biology, Gettysburg College, Gettysburg, United States
| | - Eunsoo Kim
- Division of Invertebrate Zoology, American Museum of Natural History, New York, United States
- Sackler Institute for Comparative Genomics, American Museum of Natural History, New York, United States
| | - Ryan Kerney
- Department of Biology, Gettysburg College, Gettysburg, United States
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9
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Egg Hypoxia Decreases Posthatching Survival and Delays Metamorphosis inAmbystoma maculatum(Spotted Salamander). J HERPETOL 2015. [DOI: 10.1670/14-043r1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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10
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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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12
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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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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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14
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Bloor ISM, Attrill MJ, Jackson EL. A review of the factors influencing spawning, early life stage survival and recruitment variability in the common cuttlefish (Sepia officinalis). ADVANCES IN MARINE BIOLOGY 2013; 65:1-65. [PMID: 23763891 DOI: 10.1016/b978-0-12-410498-3.00001-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Global landings of cephalopods (cuttlefish, squid and octopus) have increased dramatically over the past 50 years and now constitute almost 5% of the total world's fisheries production. At a time when landings of many traditional fin-fish stocks are continuing to experience a global decline as a result of over-exploitation, it is expected that fishing pressure on cephalopod stocks will continue to rise as the fishing industry switch their focus onto these non-quota species. However, long-term trends indicate that landings may have begun to plateau or even decrease. In European waters, cuttlefish are among the most important commercial cephalopod resource and are currently the highest yielding cephalopod group harvested in the north-east Atlantic, with the English Channel supporting the main fishery for this species. Recruitment variability in this short-lived species drives large fluctuations in landings. In order to provide sustainable management for Sepia officinalis populations, it is essential that we first have a thorough understanding of the ecology and life history of this species, in particular, the factors affecting spawning, early life stage (ELS) survival and recruitment variability. This review explores how and why such variability exists, starting with the impact of maternal effects (e.g. navigation, migration and egg laying), moving onto the direct impact of environmental variation on embryonic and ELSs and culminating on the impacts that these variations (maternal and environmental) have at a population level on annual recruitment success. Understanding these factors is critical to the effective management of expanding fisheries for this species.
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Affiliation(s)
- Isobel S M Bloor
- Marine Biological Association of the United Kingdom, The Laboratory, Citadel Hill, Plymouth, UK.
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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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17
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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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18
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Olivier HM, Moon BR. The effects of atrazine on spotted salamander embryos and their symbiotic alga. ECOTOXICOLOGY (LONDON, ENGLAND) 2010; 19:654-661. [PMID: 19924530 DOI: 10.1007/s10646-009-0437-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/30/2009] [Indexed: 05/28/2023]
Abstract
Worldwide amphibian declines have been a concern for biologists for the past several decades. The causes of such declines may include habitat loss, invasive species, pathogens, and man-made chemicals. Agricultural herbicides, in particular, are known to interfere with reproduction in amphibians and are likely contributing to population declines. We tested the effects of the herbicide atrazine on developing spotted salamanders (Ambystoma maculatum) and their symbiotic green alga Oophila amblystomatis. We exposed spotted salamander egg masses to atrazine at concentrations of 0 microg/L (control), 50, 100, 200, and 400 microg/L. Algae were eliminated in all atrazine treatments. Hatching success was significantly lower for atrazine-treated egg masses than for the controls, and was inversely related to atrazine concentration. The highest developmental stage reached by the embryos was significantly lower in the atrazine treatments than in the controls, and was inversely related to atrazine concentration. These results indicate that atrazine exposure affected spotted salamanders both directly by causing pathologies and mortality in embryos and indirectly by eliminating their symbiotic alga.
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Affiliation(s)
- Heather M Olivier
- Department of Biology, University of Louisiana at Lafayette, Lafayette, LA 70504-2451, USA.
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19
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Tattersall GJ, Spiegelaar N. Embryonic motility and hatching success of Ambystoma maculatum are influenced by a symbiotic alga. CAN J ZOOL 2008. [DOI: 10.1139/z08-115] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To augment O2supply through the jelly mass and egg capsule, embryonic yellow-spotted salamanders ( Ambystoma maculatum (Shaw, 1802)) take advantage of a unicellular alga, Oophila ambystomatis . Convective currents from surface cilia, however, may also enhance O2transport, whereas muscular contractions could either enhance delivery or contribute to O2consumption. Embryonic motion is, therefore, potentially vital to salamander development. We examined embryonic motility across multiple developmental stages, survivorship, and hatching timing in response to different algal levels by rearing salamander egg masses under three different diel light cycles: 24 h dark, 12 h light, and 24 h light per day. Embryos raised in continuous light hatched synchronously and at slightly earlier developmental stages than embryos raised in the dark or in 12 h light per day. We removed eggs at multiple stages to examine embryonic rotation and muscular contraction rates under 180 min periods of both light and dark. Rotational movements occurred more frequently in alga-free than in algae-inhabited eggs, and more frequently in algae-inhabited eggs in the dark than in light. At later developmental stages, muscular contractions were more frequent in embryos from algae-inhabited egg masses in light than those in the dark; thus embryos with less O2reduced muscular activity, thereby reducing energy consumption when O2availability was compromised.
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Affiliation(s)
- Glenn J. Tattersall
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada; Wildlife Research Station, Algonquin Park, ON K0J 2M0, Canada
| | - Nicole Spiegelaar
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada; Wildlife Research Station, Algonquin Park, ON K0J 2M0, Canada
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20
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Woods HA, Podolsky RD. Photosynthesis drives oxygen levels in macrophyte-associated gastropod egg masses. THE BIOLOGICAL BULLETIN 2007; 213:88-94. [PMID: 17679723 DOI: 10.2307/25066621] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Many aquatic animals deposit fertilized eggs in adherent clutches or gelatinous masses. Egg aggregation carries certain risks, including the potential for inadequate oxygen supply to embryos. Physical and biological conditions alter such risks. We examined the effects of light levels and associated photosynthetic organisms on the distribution of oxygen inside gelatinous egg masses of four temperate gastropod species. Egg masses of two species, the opisthobranchs Melanochlamys diomedea and Haminoea callidegenita, contained significant populations of diatoms but generally were not associated with macrophytes. Egg masses of the other two species, the opisthobranch Haminoea vesicula and the prosobranch Lacuna sp., occurred commonly on subtidal macrophytes and appeared not to contain significant populations of diatoms. In the laboratory, we used microelectrodes to measure oxygen levels inside masses exposed to alternating dark and light conditions; light level had an enormous influence on oxygen profiles in egg masses of all four species. Masses of H. vesicula and Lacuna sp., when experimentally separated from their macrophytes, showed only slight increases in oxygen upon light exposure, indicating that the main source of oxygen in situ was the macrophyte rather than associated microalgae. Our findings indicate that photosynthesis by macrophytes can drive large changes in internal oxygen profiles.
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Affiliation(s)
- H Arthur Woods
- Division of Biological Sciences, University of Montana, Missoula, Montana 59812, USA.
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21
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Valls JH, Mills NE. Intermittent hypoxia in eggs ofAmbystoma maculatum: embryonic development and egg capsule conductance. J Exp Biol 2007; 210:2430-5. [PMID: 17601946 DOI: 10.1242/jeb.003541] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYThe spotted salamander Ambystoma maculatum breeds in shallow freshwater pools and imbeds its eggs within a common outer jelly matrix that can limit oxygen availability. The eggs are impregnated with the unicellular alga Oophilia amblystomatis, which produces oxygen during the day but consumes oxygen at night. This daily cycle of algal oxygen production drives a diurnal fluctuation of oxygen partial pressure(PO2) within the eggs, the magnitude of which depends on the distance of an egg from the exterior of the jelly matrix and on the ambient PO2 of the pond. We subjected A. maculatum eggs to fluctuating oxygen levels with a variable minimum PO2 and an invariable maximum, to simulate natural conditions, and measured differences in developmental rate,day and stage at hatching, and egg capsule conductance(GO2). Lower minimum PO2 slowed development and resulted in delayed,yet developmentally premature hatching. GO2increased in all treatments throughout development, but PO2 had no detectable effect on the increase. Intermittent hypoxia caused comparable but less pronounced developmental delays than chronic hypoxia and failed to elicit the measurable change in GO2 seen in ambystomatid salamander eggs exposed to chronic hypoxia.
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Affiliation(s)
- J Hunter Valls
- Department of Biology, Harding University, Searcy, AR 72149, USA
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22
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Mitchell NJ, Seymour RS. The effects of nest temperature, nest substrate, and clutch size on the oxygenation of embryos and larvae of the Australian moss frog, Bryobatrachus nimbus. Physiol Biochem Zool 2003; 76:60-71. [PMID: 12695987 DOI: 10.1086/345486] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/19/2002] [Indexed: 11/03/2022]
Abstract
The jelly around amphibian eggs presents a formidable barrier to oxygen diffusion. Therefore, egg capsules must be thin enough, and the dimensions of globular egg masses small enough, to avoid oxygen limitation leading to developmental retardation or death. The eggs of the Australian moss frog, Bryobatrachus nimbus, have the thickest jelly capsule known for any anuran amphibian. Laboratory measurements of respirometric variables predict that single prehatching embryos should be normoxic between 5 degrees and 20 degrees C, with Po(2 in) maintained above critical levels (10.2-17.0 kPa). However, numerical models of embryos amid larger egg masses (13-20 eggs) predict hypoxia at temperatures above 5 degrees C. Contrary to model predictions, however, B. nimbus embryos rarely experience hypoxia in natural nests, because embryos occur in one or two layers and the moss substrate permits aeration of the lower surface while photosynthesis probably supplies oxygen directly. After hatching, larvae move to oxygen-rich regions of the jelly mass and disperse more widely within the mass as temperatures increase. Although nest characteristics relieve diffusive constraints, small clutch sizes, low rates of embryonic and larval respiration, and the cool climate occupied by B. nimbus are the main characteristics that prevent hypoxia.
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Affiliation(s)
- Nicola J Mitchell
- Department of Environmental Biology, University of Adelaide, Adelaide, South Australia 5005, Australia.
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23
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Mills NE, Barnhart MC, Semlitsch RD. Effects of hypoxia on egg capsule conductance inAmbystoma(Class Amphibia, Order Caudata). J Exp Biol 2001; 204:3747-53. [PMID: 11719538 DOI: 10.1242/jeb.204.21.3747] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
SUMMARYAquatic amphibian eggs frequently encounter hypoxic conditions that have the potential to limit oxygen uptake and thereby slow embryonic development and hatching. Oxygen limitation might be avoided if egg capsule surface area and oxygen conductance increased in response to hypoxia. We investigated this possibility in two salamander species, Ambystoma annulatum and Ambystoma talpoideum. The effective surface area of egg capsules increased in response to hypoxia, which increased the conductance for oxygen and enhanced oxygen transport. The ability of amphibian eggs to adjust their conductance in response to oxygen availability may increase survival in hypoxic environments.
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Affiliation(s)
- N E Mills
- Department of Biology, Southwest Missouri State University, Springfield, MO 65804, USA.
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24
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Mills NE, Barnhart MC. Effects of hypoxia on embryonic development in two Ambystoma and two Rana species. Physiol Biochem Zool 1999; 72:179-88. [PMID: 10068621 DOI: 10.1086/316657] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Oxygen available to amphibian embryos fluctuates widely and is often very low. We investigated the effects of oxygen partial pressure (1. 3-16.9 kPa) on embryonic development and hatching of two salamander (Ambystoma) and two frog (Rana) species. In Ambystoma, chronic hypoxia resulted in slowed development, delayed hatching, and embryos that were less developed at the time of hatching. Although hypoxia was not lethal to embryos, temporary developmental abnormalities were observed in Ambystoma at oxygen partial pressures of 3.8 kPa and below. Posthatching survival decreased below 3.3 kPa. In Rana, hypoxia did not affect developmental rate, presumably because hatching occurs at a very early stage of development relative to Ambystoma. However, Rana embryos hatched sooner in hypoxia than in normoxia, resulting in less developed embryos at the time of hatching. The results suggest that embryonic hypoxia may negatively affect survival and fitness in these species.
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Affiliation(s)
- N E Mills
- Department of Biology, Southwest Missouri State University, Springfield, Missouri 65804.
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25
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Canini A, Caiola MG. Characterization of gonidial zone ofCycas revolutacoralloid roots by means of microelectrodes. FEMS Microbiol Lett 1993. [DOI: 10.1111/j.1574-6968.1993.tb06146.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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26
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Grilli Caiola M, Canini A, Moscone D. Oxygen concentration, nitrogenase activity and heterocyst frequency in the leaf cavities ofAzolla filiculoidesLam. FEMS Microbiol Lett 1989. [DOI: 10.1111/j.1574-6968.1989.tb03126.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Albers PH, Prouty RM. Survival of spotted salamander eggs in temporary woodland ponds of coastal Maryland. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 1987; 46:45-61. [PMID: 15092741 DOI: 10.1016/0269-7491(87)90144-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/1986] [Accepted: 12/01/1986] [Indexed: 05/24/2023]
Abstract
Temporary ponds on the Atlantic Coastal Plain in maryland were characterized according to water chemistry, rain input, phytoplankton, zooplankton and use by the spotted salamander Ambystoma maculatum during March-October 1983-1984. Neither the number of egg masses per unit of pond surface (abundance) nor the survival of spotted salamander embryos was significantly correlated (P>0.05) with pond pH. Rainfall during May-July significantly increased the hydrogen ion concentration of 5 of 11 ponds evaluated for the impact of rainfall during the previous 48h and the previous week. Survival of egg masses transferred among eight ponds with pH3.66-4.45 and one pond with pH5.18 was significantly reduced (P<or=0.05) only at pH 3.66. Embryonic survival was negatively correlated (P<or=0.05) with the concentration of aluminium in the pond water. The abundance of egg masses was positively correlated (P<or=0.05) with water temperature and magnesium concentration, and total chlorophyll during the larval period. Yearly variability of pond characteristics (e.g. water chemistry, pond longevity) and amphibian reproduction make it difficult to determine the effects of acidic deposition on the spotted salamander. At the present time, pond longevity, water temperature and possibly, oxygen content, seem more important to spotted salamander reproduction than chemical changes caused by annual acidic deposition.
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Affiliation(s)
- P H Albers
- US Fish and Wildlife Service, Patuxent Wildlife Research Center, Laurel, Maryland 20708, USA
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