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Harris OK, Kingston ACN, Wolfe CS, Ghoshroy S, Johnsen S, Speiser DI. Core-shell nanospheres behind the blue eyes of the bay scallop Argopecten irradians. J R Soc Interface 2019; 16:20190383. [PMID: 31640501 PMCID: PMC6833330 DOI: 10.1098/rsif.2019.0383] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The bay scallop Argopecten irradians (Mollusca: Bivalvia) has dozens of iridescent blue eyes that focus light using mirror-based optics. Here, we test the hypothesis that these eyes appear blue because of photonic nanostructures that preferentially scatter short-wavelength light. Using transmission electron microscopy, we found that the epithelial cells covering the eyes of A. irradians have three distinct layers: an outer layer of microvilli, a middle layer of random close-packed nanospheres and an inner layer of pigment granules. The nanospheres are approximately 180 nm in diameter and consist of electron-dense cores approximately 140 nm in diameter surrounded by less electron-dense shells 20 nm thick. They are packed at a volume density of approximately 60% and energy-dispersive X-ray spectroscopy indicates that they are not mineralized. Optical modelling revealed that the nanospheres are an ideal size for producing angle-weighted scattering that is bright and blue. A comparative perspective supports our hypothesis: epithelial cells from the black eyes of the sea scallop Placopecten magellanicus have an outer layer of microvilli and an inner layer of pigment granules but lack a layer of nanospheres between them. We speculate that light-scattering nanospheres help to prevent UV wavelengths from damaging the internal structures of the eyes of A. irradians and other blue-eyed scallops.
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Affiliation(s)
- Olivia K Harris
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.,Department of Biological Sciences, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Alexandra C N Kingston
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Caitlin S Wolfe
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
| | - Soumitra Ghoshroy
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA.,Electron Microscopy Center, University of South Carolina, Columbia, SC 29208, USA
| | - Sönke Johnsen
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Daniel I Speiser
- Department of Biological Sciences, University of South Carolina, Columbia, SC 29208, USA
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Dougherty LF, Niebergall AK, Broeckling CD, Schauer KL, Li J. Brightly coloured tissues in limid bivalves chemically deter predators. ROYAL SOCIETY OPEN SCIENCE 2019; 6:191298. [PMID: 31824731 PMCID: PMC6837197 DOI: 10.1098/rsos.191298] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 09/05/2019] [Indexed: 06/10/2023]
Abstract
Members of the marine bivalve family Limidae are known for their bright appearance. In this study, their colourful tissues were examined as a defence mechanism towards predators. We showed that when attacked by the peacock mantis shrimp (Odontodactylus scyllarus), the 'disco' clam, Ctenoides ales, opened wide to expose brightly coloured tissues to the predator. The predator also significantly preferred to consume the internal, non-colourful clam tissues than the external, colourful tissues. Mass spectrometry-based metabolomic analysis confirmed that colourful tissues had significantly different chemical compositions than the non-colourful ones. The internal, non-colourful tissues had metabolite profiles more similar to an outgroup bivalve than to the species' own colourful external tissues. A number of the compounds that differentiated the colourful tissues from the non-colourful tissues appeared to be peptide-like, which potentially serve as the underlying defensive compounds. This is the first study demonstrating that colourful bivalve tissues are used for chemical defence.
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Affiliation(s)
- Lindsey F. Dougherty
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO, USA
- Museum of Natural History, University of Colorado Boulder, Boulder, CO, USA
- Department of Integrative Biology, University of California Berkeley, Berkeley, CA, USA
| | | | - Corey D. Broeckling
- Proteomics and Metabolomics Facility, Colorado State University, Fort Collins, CO, USA
| | - Kevin L. Schauer
- Genome Center of Wisconsin, University of Wisconsin Madison, Madison, WI, USA
| | - Jingchun Li
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, Boulder, CO, USA
- Museum of Natural History, University of Colorado Boulder, Boulder, CO, USA
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Dearden SJ, Ghoshal A, DeMartini DG, Morse DE. Sparkling Reflective Stacks of Purine Crystals in the Nudibranch Flabellina iodinea. THE BIOLOGICAL BULLETIN 2018; 234:116-129. [PMID: 29856671 DOI: 10.1086/698012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Although pigments contribute to much of the brilliant purple and orange coloration of the aeolid nudibranch Flabellina iodinea, the optical appearance of the animal was found to be augmented by dynamically sparkling, brightly reflective material in cells located throughout its epidermis. Electron microscopy revealed that specialized cells most abundant near the epithelial basal lamina contain numerous multilayer stacks of crystals, each within a fragile membrane capsule. High-resolution light microscopy of tissue sections showed that these crystalline stacks intermittently reflect light, with a temporally dynamic, sparkling appearance, suggesting that they are free to move-a phenomenon also observed in the live, intact whole animal and in the purified crystal stacks as well. Thin-layer chromatography and ultraviolet spectrometry show that the crystals isolated from all epithelial tissues are identical in composition, with guanine being the major component and its derivative, hypoxanthine, a minor component, regardless of the tissue's pigmentary color. Electron diffraction of the crystals purified separately from the orange and purple tissues exhibits nearly identical lattice parameters that closely match those measured for guanine crystals, which are widely distributed in other biophotonic systems ranging from marine invertebrates to terrestrial vertebrates. Heterogeneity of the thickness and spacing of the crystals within their stacks accounts for their broadband silvery reflectance. The optical appearance of the epidermis of this nudibranch thus results from the interaction of incident light with mobile stacks of purine crystals, augmenting the effects of its pigmentary colors.
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Kolle M, Lee S. Progress and Opportunities in Soft Photonics and Biologically Inspired Optics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2018; 30:1702669. [PMID: 29057519 DOI: 10.1002/adma.201702669] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 06/13/2017] [Indexed: 05/24/2023]
Abstract
Optical components made fully or partially from reconfigurable, stimuli-responsive, soft solids or fluids-collectively referred to as soft photonics-are poised to form the platform for tunable optical devices with unprecedented functionality and performance characteristics. Currently, however, soft solid and fluid material systems still represent an underutilized class of materials in the optical engineers' toolbox. This is in part due to challenges in fabrication, integration, and structural control on the nano- and microscale associated with the application of soft components in optics. These challenges might be addressed with the help of a resourceful ally: nature. Organisms from many different phyla have evolved an impressive arsenal of light manipulation strategies that rely on the ability to generate and dynamically reconfigure hierarchically structured, complex optical material designs, often involving soft or fluid components. A comprehensive understanding of design concepts, structure formation principles, material integration, and control mechanisms employed in biological photonic systems will allow this study to challenge current paradigms in optical technology. This review provides an overview of recent developments in the fields of soft photonics and biologically inspired optics, emphasizes the ties between the two fields, and outlines future opportunities that result from advancements in soft and bioinspired photonics.
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Affiliation(s)
- Mathias Kolle
- Department of Mechanical Engineering, Massachusetts Institute of Technology (MIT), Cambridge, MA, 02139, USA
| | - Seungwoo Lee
- SKKU Advanced Institute of Nanotechnology (SAINT), Department of Nano Engineering and School of Chemical Engineering, Sungkyunkwan University (SKKU), Suwon, 16419, Republic of Korea
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Dougherty LF, Dubielzig RR, Schobert CS, Teixeira LB, Li J. Do you see what I see? Optical morphology and visual capability of 'disco' clams ( Ctenoides ales). Biol Open 2017; 6:648-653. [PMID: 28396488 PMCID: PMC5450326 DOI: 10.1242/bio.024570] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 03/29/2017] [Indexed: 11/20/2022] Open
Abstract
The 'disco' clam Ctenoides ales (Finlay, 1927) is a marine bivalve that has a unique, vivid flashing display that is a result of light scattering by silica nanospheres and rapid mantle movement. The eyes of C. ales were examined to determine their visual capabilities and whether the clams can see the flashing of conspecifics. Similar to the congener C. scaber, C. ales exhibits an off-response (shadow reflex) and an on-response (light reflex). In field observations, a shadow caused a significant increase in flash rate from a mean of 3.9 Hz to 4.7 Hz (P=0.0016). In laboratory trials, a looming stimulus, which increased light intensity, caused a significant increase in flash rate from a median of 1.8 Hz to 2.2 Hz (P=0.0001). Morphological analysis of the eyes of C. ales revealed coarsely-packed photoreceptors lacking sophisticated structure, resulting in visual resolution that is likely too low to detect the flashing of conspecifics. As the eyes of C. ales are incapable of perceiving conspecific flashing, it is likely that their vision is instead used to detect predators.
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Affiliation(s)
- Lindsey F Dougherty
- Department of Integrative Biology, University of California Berkeley, 3040 VLSB #3140, Berkeley, CA 94720, USA
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, 334 UCB, Boulder, CO 80309, USA
- Museum of Natural History, University of Colorado Boulder, 265 UCB, Boulder, CO 80302, USA
| | - Richard R Dubielzig
- Pathobiological Sciences Department School of Veterinary Medicine, University of Wisconsin, Madison, 2015 Linden Drive, Madison, WI 53706, USA
| | - Charles S Schobert
- Pathobiological Sciences Department School of Veterinary Medicine, University of Wisconsin, Madison, 2015 Linden Drive, Madison, WI 53706, USA
| | - Leandro B Teixeira
- Pathobiological Sciences Department School of Veterinary Medicine, University of Wisconsin, Madison, 2015 Linden Drive, Madison, WI 53706, USA
| | - Jingchun Li
- Department of Ecology and Evolutionary Biology, University of Colorado Boulder, 334 UCB, Boulder, CO 80309, USA
- Museum of Natural History, University of Colorado Boulder, 265 UCB, Boulder, CO 80302, USA
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Ball P. How the disco clam got its flash. Nature 2014. [DOI: 10.1038/nature.2014.15462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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