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Zhe Guan, Tiantian Cai, Zhongmin Liu, Yunfeng Dou, Xuesong Hu, Peng Zhang, Xin Sun, Hongwei Li, Yao Kuang, Qiran Zhai, Hao Ruan, Xuanxuan Li, Zeyang Li, Qihui Zhu, Jingeng Mai, Qining Wang, Luhua Lai, Jianguo Ji, Haiguang Liu, Bin Xia, Taijiao Jiang, Shu-Jin Luo, Hong-Wei Wang, Can Xie
Cephalopods, the group of animals including octopus, squid, and cuttlefish, have remarkable ability to instantly modulate body coloration and patterns so as to blend into surrounding environments [1, 2] or send warning signals to other animals [3]. Reflectin is expressed exclusively in cephalopods, filling the lamellae of intracellular Bragg reflectors that exhibit dynamic iridescence and structural color change [4]. Here, we trace the possible origin of the reflectin gene back to a transposon from the symbiotic bioluminescent bacterium Vibrio fischeri and report the hierarchical structural architecture of reflectin protein...
September 25, 2017: Current Biology: CB
Kathryn D Feller, Thomas M Jordan, David Wilby, Nicholas W Roberts
Many animals use structural coloration to create bright and conspicuous visual signals. Selection of the size and shape of the optical structures animals use defines both the colour and intensity of the light reflected. The material used to create these reflectors is also important; however, animals are restricted to a limited number of materials: commonly chitin, guanine and the protein, reflectin. In this work we highlight that a particular set of material properties can also be under selection in order to increase the optical functionality of structural reflectors...
July 5, 2017: Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences
Kyle L Naughton, Long Phan, Erica M Leung, Rylan Kautz, Qiyin Lin, Yegor Van Dyke, Benedetta Marmiroli, Barbara Sartori, Andy Arvai, Sheng Li, Michael E Pique, Mahan Naeim, Justin P Kerr, Mercedeez J Aquino, Victoria A Roberts, Elizabeth D Getzoff, Chenhui Zhu, Sigrid Bernstorff, Alon A Gorodetsky
Films from the cephalopod protein reflectin demonstrate multifaceted functionality as infrared camouflage coatings, proton transport media, and substrates for growth of neural stem cells. A detailed study of the in vitro formation, structural characteristics, and stimulus response of such films is presented. The reported observations hold implications for the design and development of advanced cephalopod-inspired functional materials.
October 2016: Advanced Materials
Daniel G DeMartini, Michi Izumi, Aaron T Weaver, Erica Pandolfi, Daniel E Morse
The reversible assembly of reflectin proteins drives dynamic iridescence in cephalopods. Squid dynamically tune the intensity and colors of iridescence generated by constructive interference from intracellular Bragg reflectors in specialized skin cells called iridocytes. Analysis of the tissue specificity of reflectin subtypes reveals that tunability is correlated with the presence of one specific reflectin sequence. Differential phosphorylation and dephosphorylation of the reflectins in response to activation by acetylcholine, as well as differences in their tissue-specific and subcellular spatial distributions, further support the suggestion of different roles for the different reflectin subtypes...
June 12, 2015: Journal of Biological Chemistry
David D Ordinario, Long Phan, Ward G Walkup, Jonah-Micah Jocson, Emil Karshalev, Nina Hüsken, Alon A Gorodetsky
Proton-conducting materials play a central role in many renewable energy and bioelectronics technologies, including fuel cells, batteries and sensors. Thus, much research effort has been expended to develop improved proton-conducting materials, such as ceramic oxides, solid acids, polymers and metal-organic frameworks. Within this context, bulk proton conductors from naturally occurring proteins have received somewhat less attention than other materials, which is surprising given the potential modularity, tunability and processability of protein-based materials...
July 2014: Nature Chemistry
Amitabh Ghoshal, Daniel G DeMartini, Elizabeth Eck, Daniel E Morse
Loliginid squid dynamically tune the structural iridescence of cells in their skin for active camouflage and communication. Bragg reflectors in these cells consist of membrane-bound lamellae periodically alternating with low refractive index extracellular spaces; neuronal signalling induces condensation of the reflectin proteins that fill the lamellae, consequently triggering the expulsion of water. This causes an increase in refractive index within the lamellae, activating reflectance, with the change in lamellar thickness and spacing progressively shifting the wavelength of reflected light...
June 6, 2014: Journal of the Royal Society, Interface
Leila F Deravi, Andrew P Magyar, Sean P Sheehy, George R R Bell, Lydia M Mäthger, Stephen L Senft, Trevor J Wardill, William S Lane, Alan M Kuzirian, Roger T Hanlon, Evelyn L Hu, Kevin Kit Parker
Cuttlefish, Sepia officinalis, possess neurally controlled, pigmented chromatophore organs that allow rapid changes in skin patterning and coloration in response to visual cues. This process of adaptive coloration is enabled by the 500% change in chromatophore surface area during actuation. We report two adaptations that help to explain how colour intensity is maintained in a fully expanded chromatophore when the pigment granules are distributed maximally: (i) pigment layers as thin as three granules that maintain optical effectiveness and (ii) the presence of high-refractive-index proteins-reflectin and crystallin-in granules...
April 6, 2014: Journal of the Royal Society, Interface
Daniel G DeMartini, Amitabh Ghoshal, Erica Pandolfi, Aaron T Weaver, Mary Baum, Daniel E Morse
Loliginid squid use tunable multilayer reflectors to modulate the optical properties of their skin for camouflage and communication. Contained inside specialized cells called iridocytes, these photonic structures have been a model for investigations into bio-inspired adaptive optics. Here, we describe two distinct sexually dimorphic tunable biophotonic features in the commercially important species Doryteuthis opalescens: bright stripes of rainbow iridescence on the mantle just beneath each fin attachment and a bright white stripe centered on the dorsal surface of the mantle between the fins...
October 1, 2013: Journal of Experimental Biology
Amitabh Ghoshal, Daniel G Demartini, Elizabeth Eck, Daniel E Morse
Cephalopods (e.g. octopus, squid and cuttlefish) dynamically tune the colour and brightness of their skin for camouflage and communication using specialized skin cells called iridocytes. We use high-resolution microspectrophotometry to investigate individual tunable Bragg structures (consisting of alternating reflectin protein-containing, high-refractive index lamellae and low-refractive index inter-lamellar spaces) in live and chemically fixed iridocytes of the California market squid, Doryteuthis opalescens...
August 6, 2013: Journal of the Royal Society, Interface
Aude Andouche, Yann Bassaglia, Sébastien Baratte, Laure Bonnaud
BACKGROUND: In the cuttlefish Sepia officinalis, iridescence is known to play a role in patterning and communication. In iridophores, iridosomes are composed of reflectins, a protein family, which show great diversity in all cephalopod species. Iridosomes are established before hatching, but very little is known about how these cells are established, their distribution in embryos, or the contribution of each reflectin gene to iridosome structures. RESULTS: Six reflectin genes are expressed during the development of iridosomes in Sepia officinalis...
May 2013: Developmental Dynamics: An Official Publication of the American Association of Anatomists
T J Wardill, P T Gonzalez-Bellido, R J Crook, R T Hanlon
Fast dynamic control of skin coloration is rare in the animal kingdom, whether it be pigmentary or structural. Iridescent structural coloration results when nanoscale structures disrupt incident light and selectively reflect specific colours. Unlike animals with fixed iridescent coloration (e.g. butterflies), squid iridophores (i.e. aggregations of iridescent cells in the skin) produce dynamically tuneable structural coloration, as exogenous application of acetylcholine (ACh) changes the colour and brightness output...
October 22, 2012: Proceedings. Biological Sciences
Yann Bassaglia, Thomas Bekel, Corinne Da Silva, Julie Poulain, Aude Andouche, Sandra Navet, Laure Bonnaud
New molecular resources regarding the so-called “non-standard models” in biology extend the present knowledge and are essential for molecular evolution and diversity studies (especially during the development) and evolutionary inferences about these zoological groups, or more practically for their fruitful management. Sepia officinalis, an economically important cephalopod species, is emerging as a new lophotrochozoan developmental model. We developed a large set of expressed sequence tags (ESTs) from embryonic stages of S...
May 1, 2012: Gene
Andrea R Tao, Daniel G DeMartini, Michi Izumi, Alison M Sweeney, Amanda L Holt, Daniel E Morse
Cephalopods are nicknamed the "masters of disguise" for their highly evolved camouflage mechanisms, including the hallmark ability to rapidly change the color and reflectance of their skin. Previously, reflectin proteins were identified as the major biomaterial component of iridosomes [1], specialized light-reflecting architectures that contribute intense structural color to squid skin, eyes, and organs [2-5]. Supramolecular assembly of reflectin has been recognized as a key property in the protein's function [6]...
February 2010: Biomaterials
Michi Izumi, Alison M Sweeney, Daniel Demartini, James C Weaver, Meghan L Powers, Andrea Tao, Tania V Silvas, Ryan M Kramer, Wendy J Crookes-Goodson, Lydia M Mäthger, Rajesh R Naik, Roger T Hanlon, Daniel E Morse
Many cephalopods exhibit remarkable dermal iridescence, a component of their complex, dynamic camouflage and communication. In the species Euprymna scolopes, the light-organ iridescence is static and is due to reflectin protein-based platelets assembled into lamellar thin-film reflectors called iridosomes, contained within iridescent cells called iridocytes. Squid in the family Loliginidae appear to be unique in which the dermis possesses a dynamic iridescent component with reflective, coloured structures that are assembled and disassembled under the control of the muscarinic cholinergic system and the associated neurotransmitter acetylcholine (ACh)...
March 6, 2010: Journal of the Royal Society, Interface
Ryan M Kramer, Wendy J Crookes-Goodson, Rajesh R Naik
Reflectins, a recently identified protein family that is enriched in aromatic and sulphur-containing amino acids, are used by certain cephalopods to manage and manipulate incident light in their environment. These proteins are the predominant constituent of nanoscaled photonic structures that function in static and adaptive colouration, extending visual performance and intra-species communication. Our investigation into recombinantly expressed reflectin has revealed unanticipated self-assembling and behavioural properties, and we demonstrate that reflectin can be easily processed into thin films, photonic grating structures and fibres...
July 2007: Nature Materials
Wendy J Crookes, Lin-Lin Ding, Qing Ling Huang, Jennifer R Kimbell, Joseph Horwitz, Margaret J McFall-Ngai
A family of unusual proteins is deposited in flat, structural platelets in reflective tissues of the squid Euprymna scolopes. These proteins, which we have named reflectins, are encoded by at least six genes in three subfamilies and have no reported homologs outside of squids. Reflectins possess five repeating domains, which are highly conserved among members of the family. The proteins have a very unusual composition, with four relatively rare residues (tyrosine, methionine, arginine, and tryptophan) comprising approximately 57% of a reflectin, and several common residues (alanine, isoleucine, leucine, and lysine) occurring in none of the family members...
January 9, 2004: Science
E LeBrun, R van Rapenbusch
The tertiary structure of Bacillus subtilis levansucrase (EC at 3.8 A resolution has been obtained from x-ray diffraction data by the method of multiple isomorphous replacements using three heavy atom derivatives. The crystals belong to space group P212121 with 1 molecule/crystallographic asymmetric unit. Unit cell dimensions are: a = 53.8 A, b = 67.7 A, and c = 125.6 A. Isomorphous heavy atom derivatives were prepared by soaking crystals in solutions containing K2Hg(CN)4, KAu(CN)2, and K2PtCl6. Precession photographs were taken of 29 reciprocal lattice planes of the native compound and three derivatives...
December 25, 1980: Journal of Biological Chemistry
B Rippe, B Folkow
Transcapillary passage of plasma proteins is enhanced in man's primary hypertension and it is debated whether this reflects increased permeability or merely a raised capillary pressure. To elucidate this problem, maximally vasodilated hindquarters of spontaneously hypertensive rats (SHR) and normotensive controls (NCR) were perfused in parallel at constant flow with dextran, horse serum or mixtures of the two, using labelled albumin as indicator of capillary permeability to macromolecules. By equal increases of venous pressure modest filtration was maintained during one hour, after which the edema and its albumin content were determined...
September 1977: Acta Physiologica Scandinavica
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