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  1. Article ; Online: Teeth outside the mouth: The evolution and development of shark denticles.

    Cooper, Rory L / Nicklin, Ella F / Rasch, Liam J / Fraser, Gareth J

    Evolution & development

    2023  Volume 25, Issue 1, Page(s) 54–72

    Abstract: Vertebrate skin appendages are incredibly diverse. This diversity, which includes structures such as scales, feathers, and hair, likely evolved from a shared anatomical placode, suggesting broad conservation of the early development of these organs. Some ...

    Abstract Vertebrate skin appendages are incredibly diverse. This diversity, which includes structures such as scales, feathers, and hair, likely evolved from a shared anatomical placode, suggesting broad conservation of the early development of these organs. Some of the earliest known skin appendages are dentine and enamel-rich tooth-like structures, collectively known as odontodes. These appendages evolved over 450 million years ago. Elasmobranchs (sharks, skates, and rays) have retained these ancient skin appendages in the form of both dermal denticles (scales) and oral teeth. Despite our knowledge of denticle function in adult sharks, our understanding of their development and morphogenesis is less advanced. Even though denticles in sharks appear structurally similar to oral teeth, there has been limited data directly comparing the molecular development of these distinct elements. Here, we chart the development of denticles in the embryonic small-spotted catshark (Scyliorhinus canicula) and characterize the expression of conserved genes known to mediate dental development. We find that shark denticle development shares a vast gene expression signature with developing teeth. However, denticles have restricted regenerative potential, as they lack a sox2+ stem cell niche associated with the maintenance of a dental lamina, an essential requirement for continuous tooth replacement. We compare developing denticles to other skin appendages, including both sensory skin appendages and avian feathers. This reveals that denticles are not only tooth-like in structure, but that they also share an ancient developmental gene set that is likely common to all epidermal appendages.
    MeSH term(s) Animals ; Sharks ; Dental Pulp Calcification ; Tooth ; Vertebrates ; Odontogenesis
    Language English
    Publishing date 2023-01-03
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2020288-X
    ISSN 1525-142X ; 1520-541X
    ISSN (online) 1525-142X
    ISSN 1520-541X
    DOI 10.1111/ede.12427
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Aedes aegypti CCEae3A carboxylase expression confers carbamate, organophosphate and limited pyrethroid resistance in a model transgenic mosquito.

    Poulton, Beth C / Colman, Fraser / Anthousi, Amalia / Sattelle, David B / Lycett, Gareth J

    PLoS neglected tropical diseases

    2024  Volume 18, Issue 2, Page(s) e0011595

    Abstract: Insecticide resistance is a serious threat to our ability to control mosquito vectors which transmit pathogens including malaria parasites and arboviruses. Understanding the underlying mechanisms is an essential first step in tackling the challenges ... ...

    Abstract Insecticide resistance is a serious threat to our ability to control mosquito vectors which transmit pathogens including malaria parasites and arboviruses. Understanding the underlying mechanisms is an essential first step in tackling the challenges presented by resistance. This study aimed to functionally characterise the carboxylesterase, CCEae3A, the elevated expression of which has been implicated in temephos resistance in Aedes aegypti and Aedes albopictus larvae. Using our GAL4/UAS expression system, already established in insecticide-sensitive Anopheles gambiae mosquitoes, we produced transgenic An. gambiae mosquitoes that express an Ae. aegypti CCEae3A ubiquitously. This new transgenic line permits examination of CCEae3A expression in a background in which there is not a clear orthologue in Vectorbase and allows comparison with existing An. gambiae GAL4-UAS lines. Insecticide resistance profiling of these transgenic An. gambiae larvae indicated significant increases in resistance ratio for three organophosphate insecticides, temephos (6), chloropyriphos (6.6) and fenthion (3.2) when compared to the parental strain. Cross resistance to adulticides from three major insecticide classes: organophosphates (malathion, fenitrothion and pirimiphos methyl), carbamates (bendiocarb and propoxur) and pyrethroid (alpha-cypermethrin) was also detected. Resistance to certain organophosphates and carbamates validates conclusions drawn from previous expression and phenotypic data. However, detection of resistance to pirimiphos methyl and alphacypermethrin has not previously been formally associated with CCEae3A, despite occurring in Ae. aegypti strains where this gene was upregulated. Our findings highlight the importance of characterising individual resistance mechanisms, thereby ensuring accurate information is used to guide future vector control strategies.
    MeSH term(s) Animals ; Aedes/genetics ; Carbamates ; Insecticides/pharmacology ; Organophosphates/pharmacology ; Temefos/pharmacology ; Animals, Genetically Modified ; Pyrethrins ; Organothiophosphorus Compounds
    Chemical Substances pirimiphos methyl (29232-93-7) ; Carbamates ; Insecticides ; Organophosphates ; Temefos (ONP3ME32DL) ; cypermethrin (1TR49121NP) ; Pyrethrins ; Organothiophosphorus Compounds
    Language English
    Publishing date 2024-02-20
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2429704-5
    ISSN 1935-2735 ; 1935-2735
    ISSN (online) 1935-2735
    ISSN 1935-2735
    DOI 10.1371/journal.pntd.0011595
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Embryonic development in the bonnethead (Sphyrna tiburo), a viviparous hammerhead shark.

    Byrum, Steven R / Frazier, Bryan S / Grubbs, R Dean / Naylor, Gavin J P / Fraser, Gareth J

    Developmental dynamics : an official publication of the American Association of Anatomists

    2023  Volume 253, Issue 3, Page(s) 351–362

    Abstract: Background: The hammerhead sharks (family Sphyrnidae) are an immediately recognizable group of sharks due to their unique head shape. Though there has long been an interest in hammerhead development, there are currently no explicit staging tables ... ...

    Abstract Background: The hammerhead sharks (family Sphyrnidae) are an immediately recognizable group of sharks due to their unique head shape. Though there has long been an interest in hammerhead development, there are currently no explicit staging tables published for any members of the group. The bonnethead Sphyrna tiburo is the smallest member of Sphyrnidae and is abundant in estuarine and nearshore waters in the Gulf of Mexico and Western North Atlantic Ocean. Due to their relative abundance, close proximity to shore, and brief gestation period, it has been possible to collect and document multiple embryonic specimens at progressive stages of development.
    Results: We present the first comprehensive embryonic staging series for the Bonnethead, a viviparous hammerhead shark. Our stage series covers a period of development from stages that match the vertebrate phylotypic period, from Stage 23, through stages of morphological divergence to complete development at birth-Stage 35). Notably, we use a variety of techniques to document crucial stages that lead to their extreme craniofacial diversity, resulting in the formation of one of the most distinctive characters of any shark species, the cephalofoil or hammer-like head.
    Conclusion: Documenting the development of hard-to-access vertebrates, like this viviparous shark species, offers important information about how new and diverse morphologies arise that otherwise may remain poorly studied. This work will serve as a platform for future comparative developmental research both within sharks and across the phylogeny of vertebrates, underpinning the extreme potential of craniofacial development and morphological diversity in vertebrate animals.
    MeSH term(s) Animals ; Sharks ; Phylogeny ; Birds ; Embryonic Development
    Language English
    Publishing date 2023-09-28
    Publishing country United States
    Document type Journal Article ; Review
    ZDB-ID 1102541-4
    ISSN 1097-0177 ; 1058-8388
    ISSN (online) 1097-0177
    ISSN 1058-8388
    DOI 10.1002/dvdy.658
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: An epithelial signalling centre in sharks supports homology of tooth morphogenesis in vertebrates.

    Thiery, Alexandre P / Standing, Ariane S I / Cooper, Rory L / Fraser, Gareth J

    eLife

    2022  Volume 11

    Abstract: Development of tooth shape is regulated by the enamel knot signalling centre, at least in mammals. Fgf signalling regulates differential proliferation between the enamel knot and adjacent dental epithelia during tooth development, leading to formation of ...

    Abstract Development of tooth shape is regulated by the enamel knot signalling centre, at least in mammals. Fgf signalling regulates differential proliferation between the enamel knot and adjacent dental epithelia during tooth development, leading to formation of the dental cusp. The presence of an enamel knot in non-mammalian vertebrates is debated given differences in signalling. Here, we show the conservation and restriction of
    MeSH term(s) Animals ; Mammals ; Mice ; Morphogenesis/genetics ; Odontogenesis/genetics ; Sharks ; Tooth ; Vertebrates
    Language English
    Publishing date 2022-05-10
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2687154-3
    ISSN 2050-084X ; 2050-084X
    ISSN (online) 2050-084X
    ISSN 2050-084X
    DOI 10.7554/eLife.73173
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  5. Article ; Online: An epithelial signalling centre in sharks supports homology of tooth morphogenesis in vertebrates

    Alexandre P Thiery / Ariane SI Standing / Rory L Cooper / Gareth J Fraser

    eLife, Vol

    2022  Volume 11

    Abstract: Development of tooth shape is regulated by the enamel knot signalling centre, at least in mammals. Fgf signalling regulates differential proliferation between the enamel knot and adjacent dental epithelia during tooth development, leading to formation of ...

    Abstract Development of tooth shape is regulated by the enamel knot signalling centre, at least in mammals. Fgf signalling regulates differential proliferation between the enamel knot and adjacent dental epithelia during tooth development, leading to formation of the dental cusp. The presence of an enamel knot in non-mammalian vertebrates is debated given differences in signalling. Here, we show the conservation and restriction of fgf3, fgf10, and shh to the sites of future dental cusps in the shark (Scyliorhinus canicula), whilst also highlighting striking differences between the shark and mouse. We reveal shifts in tooth size, shape, and cusp number following small molecule perturbations of canonical Wnt signalling. Resulting tooth phenotypes mirror observed effects in mammals, where canonical Wnt has been implicated as an upstream regulator of enamel knot signalling. In silico modelling of shark dental morphogenesis demonstrates how subtle changes in activatory and inhibitory signals can alter tooth shape, resembling developmental phenotypes and cusp shapes observed following experimental Wnt perturbation. Our results support the functional conservation of an enamel knot-like signalling centre throughout vertebrates and suggest that varied tooth types from sharks to mammals follow a similar developmental bauplan. Lineage-specific differences in signalling are not sufficient in refuting homology of this signalling centre, which is likely older than teeth themselves.
    Keywords shark ; Scyliorhinus canicula ; tooth development ; morphogenesis ; gene expression ; dental evolution ; Medicine ; R ; Science ; Q ; Biology (General) ; QH301-705.5
    Subject code 570
    Language English
    Publishing date 2022-05-01T00:00:00Z
    Publisher eLife Sciences Publications Ltd
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Re-evaluating the morphological evidence for the re-evolution of lost mandibular teeth in frogs.

    Paluh, Daniel J / Dillard, Wesley A / Stanley, Edward L / Fraser, Gareth J / Blackburn, David C

    Evolution; international journal of organic evolution

    2021  Volume 75, Issue 12, Page(s) 3203–3213

    Abstract: Dollo's law of irreversibility states that once a complex structure is lost, it cannot be regained in the same form. Several putative exceptions to Dollo's law have been identified using phylogenetic comparative methods, but the anatomy and development ... ...

    Abstract Dollo's law of irreversibility states that once a complex structure is lost, it cannot be regained in the same form. Several putative exceptions to Dollo's law have been identified using phylogenetic comparative methods, but the anatomy and development of these traits are often poorly understood. Gastrotheca guentheri is renowned as the only frog with teeth on the lower jaw. Mandibular teeth were lost in the ancestor of frogs more than 200 million years ago and subsequently regained in G. guentheri. Little is known about the teeth in this species despite being a frequent example of trait "re-evolution," leaving open the possibility that it may have mandibular pseudoteeth. We assessed the dental anatomy of G. guentheri using micro-computed tomography and histology and confirmed the longstanding assumption that true mandibular teeth are present. Remarkably, the mandibular teeth of G. guentheri are nearly identical in gross morphology and development to upper jaw teeth in closely related species. The developmental genetics of tooth formation are unknown in this possibly extinct species. Our results suggest that an ancestral odontogenic pathway has been conserved but suppressed in the lower jaw since the origin of frogs, providing a possible mechanism underlying the re-evolution of lost mandibular teeth.
    MeSH term(s) Animals ; Anura/genetics ; Biological Evolution ; Phylogeny ; Tooth ; X-Ray Microtomography
    Language English
    Publishing date 2021-11-09
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 2036375-8
    ISSN 1558-5646 ; 0014-3820
    ISSN (online) 1558-5646
    ISSN 0014-3820
    DOI 10.1111/evo.14379
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  7. Article ; Online: The Dental Lamina: An Essential Structure for Perpetual Tooth Regeneration in Sharks.

    Fraser, Gareth J / Standing, Ariane / Underwood, Charlie / Thiery, Alexandre P

    Integrative and comparative biology

    2020  Volume 60, Issue 3, Page(s) 644–655

    Abstract: In recent years, nonclassical models have emerged as mainstays for studies of evolutionary, developmental, and regenerative biology. Genomic advances have promoted the use of alternative taxa for the study of developmental biology, and the shark is one ... ...

    Abstract In recent years, nonclassical models have emerged as mainstays for studies of evolutionary, developmental, and regenerative biology. Genomic advances have promoted the use of alternative taxa for the study of developmental biology, and the shark is one such emerging model vertebrate. Our research utilizes the embryonic shark (Scyliorhinus canicula) to characterize key developmental and regenerative processes that have been overlooked or not possible to study with more classic developmental models. Tooth development is a major event in the construction of the vertebrate body plan, linked in part with the emergence of jaws. Early development of the teeth and morphogenesis is well known from the murine model, but the process of tooth redevelopment and regeneration is less well known. Here we explore the role of the dental lamina in the development of a highly regenerative dentition in sharks. The shark represents a polyphyodont vertebrate with continuously repeated whole tooth regeneration. This is presented as a major developmental shift from the more derived renewal process that the murine model offers, where incisors exhibit continuous renewal and growth of the same tooth. Not only does the shark offer a study system for whole unit dental regeneration, it also represents an important model for understanding the evolutionary context of vertebrate tooth regeneration.
    MeSH term(s) Animals ; Biological Evolution ; Regeneration/physiology ; Sharks/physiology ; Tooth/physiology
    Language English
    Publishing date 2020-07-14
    Publishing country England
    Document type Journal Article
    ZDB-ID 2159110-6
    ISSN 1557-7023 ; 1540-7063
    ISSN (online) 1557-7023
    ISSN 1540-7063
    DOI 10.1093/icb/icaa102
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  8. Article ; Online: Shark tooth regeneration reveals common stem cell characters in both human rested lamina and ameloblastoma.

    Fraser, Gareth J / Hamed, Samar S / Martin, Kyle J / Hunter, Keith D

    Scientific reports

    2019  Volume 9, Issue 1, Page(s) 15956

    Abstract: The human dentition is a typical diphyodont mammalian system with tooth replacement of most positions. However, after dental replacement and sequential molar development, the dental lamina undergoes apoptosis and fragments, leaving scattered epithelial ... ...

    Abstract The human dentition is a typical diphyodont mammalian system with tooth replacement of most positions. However, after dental replacement and sequential molar development, the dental lamina undergoes apoptosis and fragments, leaving scattered epithelial units (dental lamina rests; DLRs). DLRs in adult humans are considered inactive epithelia, thought to possess limited capacity for further regeneration. However, we show that these tissues contain a small proportion of proliferating cells (assessed by both Ki67 and PCNA) but also express a number of common dental stem cell markers (Sox2, Bmi1, β-catenin and PH3) similar to that observed in many vertebrates that actively, and continuously regenerate their dentition. We compared these human tissues with the dental lamina of sharks that regenerate their dentition throughout life, providing evidence that human tissues have the capacity for further and undocumented regeneration. We also assessed cases of human ameloblastoma to characterise further the proliferative signature of dental lamina rests. Ameloblastomas are assumed to derive from aberrant lamina rests that undergo changes, which are not well understood, to form a benign tumour. We suggest that dental lamina rests can offer a potential source of important dental stem cells for future dental regenerative therapy. The combined developmental genetic data from the shark dental lamina and ameloblastoma may lead to the development of novel methods to utilise these rested populations of adult lamina stem cells for controlled tooth replacement in humans.
    MeSH term(s) Adolescent ; Adult ; Animals ; Biomarkers ; Child ; Child, Preschool ; Fluorescent Antibody Technique ; Gene Expression ; Humans ; Male ; Middle Aged ; Odontogenesis ; Organogenesis ; Regeneration ; Sharks ; Stem Cells/cytology ; Stem Cells/metabolism ; Tooth/embryology ; Tooth/growth & development ; Young Adult
    Chemical Substances Biomarkers
    Language English
    Publishing date 2019-11-04
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2615211-3
    ISSN 2045-2322 ; 2045-2322
    ISSN (online) 2045-2322
    ISSN 2045-2322
    DOI 10.1038/s41598-019-52406-z
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Rationally designed chimeric PI3K-BET bromodomain inhibitors elicit curative responses in MYC-driven lymphoma.

    Oh, Danielle H / Ma, Xiao / Hogg, Simon J / He, Jackson / Kearney, Conor / Brasacchio, Daniella / Susanto, Olivia / Maher, Belinda / Jennings, Ian G / Newbold, Andrea / Fraser, Peter / Gruber, Emily / Kats, Lev M / Gregory, Gareth P / Johnstone, Ricky W / Thompson, Philip E / Shortt, Jake

    Proceedings of the National Academy of Sciences of the United States of America

    2023  Volume 120, Issue 36, Page(s) e2306414120

    Abstract: Targeted inhibitors of bromodomain and extraterminal (BET)-bromodomains and phosphatidylinositol-3-kinase (PI3K) signaling demonstrate potent but self-limited antilymphoma activity as single agents in the context of cellular Myelocytomatosis ( ...

    Abstract Targeted inhibitors of bromodomain and extraterminal (BET)-bromodomains and phosphatidylinositol-3-kinase (PI3K) signaling demonstrate potent but self-limited antilymphoma activity as single agents in the context of cellular Myelocytomatosis (
    MeSH term(s) Humans ; Phosphatidylinositol 3-Kinases ; Phosphatidylinositol 3-Kinase ; Aggression ; Epigenomics ; Lymphoma/drug therapy ; Phosphoinositide-3 Kinase Inhibitors
    Chemical Substances Phosphatidylinositol 3-Kinases (EC 2.7.1.-) ; Phosphatidylinositol 3-Kinase (EC 2.7.1.137) ; Phosphoinositide-3 Kinase Inhibitors
    Language English
    Publishing date 2023-08-29
    Publishing country United States
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 209104-5
    ISSN 1091-6490 ; 0027-8424
    ISSN (online) 1091-6490
    ISSN 0027-8424
    DOI 10.1073/pnas.2306414120
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  10. Article ; Online: Deep Fault‐Controlled Fluid Flow Driving Shallow Stratigraphically Constrained Gas Hydrate Formation

    Gorman, Andrew R. / Crutchley, Gareth J. / Baker, Dylan R. / Fraser, Douglas R. A. / Henrys, Stuart A. / Tréhu, Anne M. / Harris, Robert N. / Phrampus, Benjamin J. / Pecher, Ingo A.

    Urutī Basin, Hikurangi Margin, New Zealand

    2024  

    Abstract: The Hikurangi Margin east of New Zealand's North Island hosts an extensive gas hydrate province with numerous gas hydrate accumulations related to the faulted structure of the accretionary wedge. One such hydrate feature occurs in a small perched upper‐ ... ...

    Abstract The Hikurangi Margin east of New Zealand's North Island hosts an extensive gas hydrate province with numerous gas hydrate accumulations related to the faulted structure of the accretionary wedge. One such hydrate feature occurs in a small perched upper‐slope basin known as Urutī Basin. We investigated this hydrate accumulation by combining a long‐offset seismic line (10‐km‐long receiver array) with a grid of high‐resolution seismic lines acquired with a 600‐m‐long hydrophone streamer. The long‐offset data enable quantitative velocity analysis, while the high‐resolution data constrain the three‐dimensional geometry of the hydrate accumulation. The sediments in Urutī Basin dip landward due to ongoing deformation of the accretionary wedge. These strata are clearly imaged in seismic data where they cross a distinct bottom simulating reflection (BSR) that dips counterintuitively in the opposite direction to the regional dip of the seafloor. BSR‐derived heat flow estimates reveal a distinct heat flow anomaly that coincides spatially with the upper extent of a landward‐verging thrust fault. We present a conceptual model of this gas hydrate system that highlights the roles of fault‐controlled fluid flow at depth merging into strata‐controlled fluid flow into the hydrate stability zone. The result is a layer‐constrained accumulation of concentrated gas hydrate in the dipping strata. Our study provides new insight into the interplay between deep faulting, fluid flow and gas hydrate formation within an active accretionary margin. Plain Language Summary Gas hydrates are ice‐like substances in which natural gas molecules are trapped in a cage of water molecules. They exist where the pressure is high, temperature is cold, and enough methane is present. These conditions exist in the marine environment at water depths greater than 300–500 m near sediment‐rich continental margins and in polar regions. It is important to study gas hydrates because they represent a significant part of the Earth's carbon budget and influence the ...
    Subject code 550
    Language English
    Publishing date 2024-03-16
    Publisher AGU (American Geophysical Union)
    Publishing country de
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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