title: Extensible byssus of Pinctada fucata: Ca(2+)-stabilized nanocavities and a thrombospondin-1 protein.
abstract: The extensible byssus is produced by the foot of bivalve animals, including the pearl oyster Pinctada fucata, and enables them to attach to hard underwater surfaces. However, the mechanism of their extensibility is not well understood. To understand this mechanism, we analyzed the ultrastructure, composition and mechanical properties of the P. fucata byssus using electron microscopy, elemental analysis, proteomics and mechanical testing. In contrast to the microstructures of Mytilus sp. byssus, the P. fucata byssus has an exterior cuticle without granules and an inner core with nanocavities. The removal of Ca(2+) by ethylenediaminetetraacetic acid (EDTA) treatment expands the nanocavities and reduces the extensibility of the byssus, which is accompanied by a decrease in the β-sheet conformation of byssal proteins. Through proteomic methods, several proteins with antioxidant and anti-corrosive properties were identified as the main components of the distal byssus regions. Specifically, a protein containing thrombospondin-1 (TSP-1), which is highly expressed in the foot, is hypothesized to be responsible for byssus extensibility. Together, our findings demonstrate the importance of inorganic ions and multiple proteins for bivalve byssus extension, which could guide the future design of biomaterials for use in seawater.
authors.affiliation: Institute of Marine Biotechnology, Collaborative Innovation Center of Deep Sea Biology, School of Life Sciences, Tsinghua University, Beijing 100084 China.|Tsinghua-Peking Joint Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084 China.
authors.forename: Chuang
authors.initials: C
authors.lastname: Liu
authors.affiliation: Institute of Marine Biotechnology, Collaborative Innovation Center of Deep Sea Biology, School of Life Sciences, Tsinghua University, Beijing 100084 China.
authors.forename: Shiguo
authors.initials: S
authors.lastname: Li
authors.affiliation: Institute of Marine Biotechnology, Collaborative Innovation Center of Deep Sea Biology, School of Life Sciences, Tsinghua University, Beijing 100084 China.
authors.forename: Jingliang
authors.initials: J
authors.lastname: Huang
authors.affiliation: Institute of Marine Biotechnology, Collaborative Innovation Center of Deep Sea Biology, School of Life Sciences, Tsinghua University, Beijing 100084 China.
authors.forename: Yangjia
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Institute of Marine Biotechnology, Collaborative Innovation Center of Deep Sea Biology, School of Life Sciences, Tsinghua University, Beijing 100084 China.
authors.forename: Ganchu
authors.initials: G
authors.lastname: Jia
authors.affiliation: Institute of Marine Biotechnology, Collaborative Innovation Center of Deep Sea Biology, School of Life Sciences, Tsinghua University, Beijing 100084 China.
authors.forename: Liping
authors.initials: L
authors.lastname: Xie
authors.affiliation: Institute of Marine Biotechnology, Collaborative Innovation Center of Deep Sea Biology, School of Life Sciences, Tsinghua University, Beijing 100084 China.
authors.forename: Rongqing
authors.initials: R
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D001704:Biopolymers / Q000737:chemistry* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002413:Cations, Divalent; D015870:Gene Expression; D020869:Gene Expression Profiling; D008422:Materials Testing; D008958:Models, Molecular; D058977:Molecular Sequence Annotation; D008969:Molecular Sequence Data; D057139:Nanofibers / Q000737:chemistry / Q000648:ultrastructure*; D049911:Pinctada / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D019700:Thrombospondin 1 / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
chemical_list: D000975:Antioxidants; D001704:Biopolymers; D002413:Cations, Divalent; D019700:Thrombospondin 1; D002118:Calcium