ORCID Profile
0000-0002-2116-5651
Current Organisation
University of St Andrews
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Springer Science and Business Media LLC
Date: 11-11-2019
DOI: 10.1038/S41598-019-52850-X
Abstract: In vertebrates, the steroidogenesis enzyme 5α-reductase converts testosterone to the more potent androgen 5α-dihydrotestosterone. Homologues of 5α-reductase genes have been identified in molluscs. However, recent findings suggest that vertebrate-type steroid androgens are not utilised in molluscan reproductive development. Genomic searches have revealed that molluscs do not possess many of the steroidogenic enzymes required to make testosterone, nor a nuclear androgen receptor. Consequently, the role of 5α-reductase in molluscs presents a mystery. Here, developmental exposures of Biomphalaria glabrata to selective pharmaceutical 5α-reductase inhibitors elicited a strong, highly reproducible phenotypic response characterised by the development of elongated “banana-shaped” shell morphology. In comparison to untreated snails, the shells are open-coiled and the whorls are unattached. Dutasteride (5α-reductase inhibitor) is approximately 10-times more potent at provoking the banana-shaped shell phenotype than finasteride, paralleling the pharmaceuticals’ efficacy in humans. Other enzyme inhibitors with different modes of action were tested to investigate the specificity of the phenotype. However, only the pharmaceutical 5α-reductase inhibitors provoked the response. Dutasteride elicited the same phenotype in a second gastropod, Physella acuta . In the absence of evidence for de novo androgen steroidogenesis in molluscs, these findings suggest that novel substrates for 5α-reductase exist in gastropods, lending support to the contention that molluscan endocrinology differs from the well-characterised vertebrate endocrine system.
Publisher: Springer Science and Business Media LLC
Date: 2009
Publisher: CSIRO Publishing
Date: 2022
DOI: 10.1071/IS21075
Publisher: Public Library of Science (PLoS)
Date: 14-07-2016
Publisher: Springer Science and Business Media LLC
Date: 04-2017
DOI: 10.1038/NATURE22033
Abstract: The crown-of-thorns starfish (COTS, the Acanthaster planci species group) is a highly fecund predator of reef-building corals throughout the Indo-Pacific region. COTS population outbreaks cause substantial loss of coral cover, diminishing the integrity and resilience of reef ecosystems. Here we sequenced genomes of COTS from the Great Barrier Reef, Australia and Okinawa, Japan to identify gene products that underlie species-specific communication and could potentially be used in biocontrol strategies. We focused on water-borne chemical plumes released from aggregating COTS, which make the normally sedentary starfish become highly active. Peptide sequences detected in these plumes by mass spectrometry are encoded in the COTS genome and expressed in external tissues. The exoproteome released by aggregating COTS consists largely of signalling factors and hydrolytic enzymes, and includes an expanded and rapidly evolving set of starfish-specific ependymin-related proteins. These secreted proteins may be detected by members of a large family of olfactory-receptor-like G-protein-coupled receptors that are expressed externally, sometimes in a sex-specific manner. This study provides insights into COTS-specific communication that may guide the generation of peptide mimetics for use on reefs with COTS outbreaks.
Publisher: S. Karger AG
Date: 2011
DOI: 10.1159/000324213
Abstract: The ability of a biological system to drive the formation of a microstructure as complex and ordered as the molluscan shell is of immense interest to the fields of nanotechnology and biomedicine. Although recent studies have greatly expanded our knowledge of the genes involved in shell formation, the mechanism by which matrix proteins are regulated and directed to the appropriate region of the shell, a process critical for microstructure control, is still obscure. The formation of microstructure-specific compartments within the extrapallial cavity may be the outcome of precise regulation of the vesicle trafficking of shell components within secretory cells at the mineralization front and/or the overall organization and morphology of the mantle itself. Here, we investigate the ultrastructure of the mantle of the gastropod i Haliotis asinina /i as current models put forward to describe molluscan shell formation are primarily based on observations from bivalves despite crystallographic and molecular studies indicating large differences between molluscan classes. We find that the i H. asinina /i mantle is structurally complex and comprised of novel cells packed with a ersity of vesicle types consistent with a complex system to control the secretion of the shell matrix and associated factors.
Publisher: PeerJ
Date: 12-01-2021
DOI: 10.7717/PEERJ.10662
Abstract: Abalone shells are mainly composed of two major polymorphs of CaCO 3 that are distributed in different layers of the shell. The process of shell biomineralization is controlled by genes and proteins expressed within the mantle epithelium. In this present paper, we conducted a shell regeneration experiment to study the role of HcCNA and HcCNB (in idual subunits of calcineurin) in shell biomineralization in H. ersicolor . The results of qPCR showed that HcCNB is upregulated to a greater extent than HcCNA in the mantle after shell notching. In vivo study of the effects of rHcCNB injection showed a significantly higher percentage of regenerated shell length, but not area, in the injected group compared to the control group. In addition, SEM observation of the inner surface of the regenerated shells revealed three different zones including prismatic, nacreous, and a distinct transition zone. Changes in the crystal organization and ultrastructure are clearly evident in these three zones, particularly after 3 weeks of rHcCNB administration. We hypothesize that this is due to faster biomineralization rates in the rHcCNB treated group. Taken together, our results demonstrate that HcCNB participates in shell regeneration in H. ersicolor . As calcineurin subunits have also been implicated in shell formation in bivalves, these findings suggest that calcineurin subunits may play important roles in biomineralization in all conchiferans.
Publisher: Elsevier BV
Date: 2016
Publisher: Wiley
Date: 22-02-2018
DOI: 10.1002/WDEV.313
Abstract: Molluscan shells are externally fabricated by specialized epithelial cells on the dorsal mantle. Although a conserved set of regulatory genes appears to underlie specification of mantle progenitor cells, the genes that contribute to the formation of the mature shell are incredibly erse. Recent comparative analyses of mantle transcriptomes and shell proteomes of gastropods and bivalves are consistent with shell ersity being underpinned by a rapidly evolving mantle secretome (suite of genes expressed in the mantle that encode secreted proteins) that is the product of (a) high rates of gene co‐option into and loss from the mantle gene regulatory network, and (b) the rapid evolution of coding sequences, particular those encoding repetitive low complexity domains. Outside a few conserved genes, such as carbonic anhydrase, a so‐called “biomineralization toolkit” has yet to be discovered. Despite this, a common suite of protein domains, which are often associated with the extracellular matrix and immunity, appear to have been independently and often uniquely co‐opted into the mantle secretomes of different species. The evolvability of the mantle secretome provides a molecular explanation for the evolution and ersity of molluscan shells. These genomic processes are likely to underlie the evolution of other animal biominerals, including coral and echinoderm skeletons. This article is categorized under: Comparative Development and Evolution Regulation of Organ Diversity Comparative Development and Evolution Evolutionary Novelties
Publisher: The Royal Society
Date: 06-05-2013
Abstract: The lysine (K)-rich mantle protein (KRMP) and shematrin protein families are unique to the organic matrices of pearl oyster shells. Similar to other proteins that are constituents of tough, extracellular structures, such as spider silk, shematrins and KRMPs, contain repetitive, low-complexity domains (RLCDs). Comprehensive analysis of available gene sequences in three species of pearl oyster using BLAST and hidden Markov models reveal that both gene families have large memberships in these species. The shematrin gene family expanded before the speciation of these oysters, leading to a minimum of eight orthology groups. By contrast, KRMPs expanded primarily after speciation leading to species-specific gene repertoires. Regardless of their evolutionary history, the rapid evolution of shematrins and KRMPs appears to be the result of the intrinsic instability of repetitive sequences encoding the RLCDs, and the gain, loss and shuffling of other motifs. This mode of molecular evolution is likely to contribute to structural characteristics and evolvability of the pearl oyster shell. Based on these observations, we infer that analogous RLCD proteins throughout the animal kingdom also have the capacity to rapidly evolve and as a result change their structural properties.
Publisher: Springer Science and Business Media LLC
Date: 21-09-2016
DOI: 10.1038/NATURE18964
Publisher: Cold Spring Harbor Laboratory
Date: 18-04-2021
DOI: 10.1101/2021.04.18.440109
Abstract: Crustose coralline algae (CCA) are a group of calcifying red macroalgae crucial to tropical coral reefs because they form crusts that cement together the reef framework 1 . Previous research into the responses of CCA to ocean warming (OW) and ocean acidification (OA) have found reductions in calcification rates and survival 2,3 , with magnitude of effect being species-specific. Responses of CCA to OW and OA could be linked to evolutionary ergence time and/or their underlying molecular biology, the role of either being unknown in CCA. Here we show Sporolithon durum , a species from an earlier erged lineage that exhibits low sensitivity to climate stressors, had little change in metabolic performance and did not significantly alter the expression of any genes when exposed to temperature and pH perturbations. In contrast, Porolithon onkodes , a species from a recently erged lineage, reduced photosynthetic rates and had over 400 significantly differentially expressed genes in response to experimental treatments, with differential regulation of genes relating to physiological processes. We suggest earlier erged CCA may be resistant to OW and OA conditions predicted for 2100, whereas taxa from more recently erged lineages with demonstrated high sensitivity to climate stressors may have limited ability for acclimatisation.
Publisher: EDP Sciences
Date: 09-2008
DOI: 10.1051/PARASITE/2008153321
Abstract: Annelids have had a long history in comparative embryology and morphology, which has helped to establish them in zoology textbooks as an ideal system to understand the evolution of the typical triploblastic, coelomate, protostome condition. In recent years there has been a relative upsurge in embryological data, particularly with regard to the expression and function of developmental control genes. Polychaetes, as well as other annelids such as the parasitic leech, are now also entering the age of comparative genomics. All of this comparative data has had an important impact on our views of the ancestral conditions at various levels of the animal phylogeny, including the bilaterian ancestor and the nature of the annelid ancestor. Here we review some of the recent advances made in annelid comparative development and genomics, revealing a hitherto unsuspected level of complexity in these ancestors. It is also apparent that the transition to a parasitic lifestyle leads to, or requires, extensive modifications and derivations at both the genomic and embryological levels.
Publisher: Frontiers Media SA
Date: 08-01-2021
DOI: 10.3389/FGENE.2020.597459
Abstract: Pearls are highly prized biomineralized gemstones produced by molluscs. The appearance and mineralogy of cultured pearls can vary markedly, greatly affecting their commercial value. To begin to understand the role of pearl sacs—organs that form in host oysters from explanted mantle tissues that surround and synthesize pearls—we undertook transcriptomic analyses to identify genes that are differentially expressed in sacs producing pearls with different surface and structural characteristics. Our results indicate that gene expression profiles correlate with different pearl defects, suggesting that gene regulation in the pearl sac contributes to pearl appearance and quality. For instance, pearl sacs that produced pearls with surface non-lustrous calcification significantly down-regulate genes associated with cilia and microtubule function compared to pearl sacs giving rise to lustrous pearls. These results suggest that gene expression profiling can advance our understanding of processes that control biomineralization, which may be of direct value to the pearl industry, particularly in relation to defects that result in low value pearls.
Publisher: Brill
Date: 06-11-2020
DOI: 10.1163/22244662-20191081
Abstract: Sclerophyll woodlands and open forests once covered vast areas of eastern Australia, but have been greatly fragmented and reduced in extent since European settlement. The biogeographic and evolutionary history of the biota of eastern Australia’s woodlands also remains poorly known, especially when compared to rainforests to the east, or the arid biome to the west. Here we present an analysis of patterns of mitochondrial genetic ersity in two species of Pygopodid geckos with distributions centred on the Brigalow Belt Bioregion of eastern Queensland. One moderately large and semi-arboreal species, Paradelma orientalis , shows low genetic ersity and no clear geographic structuring across its wide range. In contrast a small and semi-fossorial species, Delma torquata , consists of two moderately ergent clades, one from the ranges and upland of coastal areas of south-east Queensland, and other centred in upland areas further inland. These data point to varying histories of geneflow and refugial persistance in eastern Australia’s vast but now fragmented open woodlands. The Carnarvon Ranges of central Queensland are also highlighted as a zone of persistence for cool and/or wet-adapted taxa, however the evolutionary history and ergence of most outlying populations in these mountains remains unstudied.
Publisher: Springer Science and Business Media LLC
Date: 12-2015
Publisher: Springer Science and Business Media LLC
Date: 05-2013
Abstract: Tyrosinases, tyrosinase-related proteins, catechol oxidases and hemocyanins comprise the type-3 copper protein family and are involved in a variety of biological processes, including pigment formation, innate immunity and oxygen transport. Although this family is present in the three domains of life, its origin and early evolution are not well understood. Previous analyses of type-3 copper proteins largely have focussed on specific animal and plant phyla. Here, we combine genomic, phylogenetic and structural analyses to show that the original type-3 copper protein possessed a signal peptide and may have been secreted (we designate proteins of this type the α subclass). This ancestral type-3 copper protein gene underwent two duplication events, the first prior to the ergence of the unikont eukaryotic lineages and the second before the ersification of animals. The former duplication gave rise to a cytosolic form (β) and the latter to a membrane-bound form (γ). Structural comparisons reveal that the active site of α and γ forms are covered by aliphatic amino acids, and the β form has a highly conserved aromatic residue in this position. The subsequent evolution of this gene family in modern lineages of multicellular eukaryotes is typified by the loss of one or more of these three subclasses and the lineage-specific expansion of one or both of the remaining subclasses. The ersity of type-3 copper proteins in animals and other eukaryotes is consistent with two ancient gene duplication events leading to α, β and γ subclasses, followed by the differential loss and expansion of one or more of these subclasses in specific kingdoms and phyla. This has led to many lineage-specific type-3 copper protein repertoires and in some cases the independent evolution of functionally-classified tyrosinases and hemocyanins. For ex le, the oxygen-carrying hemocyanins in arthropods evolved from a β-subclass tyrosinase, whilst hemocyanins in molluscs and urochordates evolved independently from an α-subclass tyrosinase. Minor conformational changes at the active site of α, β and γ forms can produce type-3 copper proteins with capacities to either carry oxygen (hemocyanins), oxidize diphenols (catechol oxidase) or o -hydroxylate monophenols (tyrosinases) and appear to underlie some functional convergences.
Publisher: PeerJ
Date: 09-04-2020
DOI: 10.7717/PEERJ.8868
Abstract: Calcineurin (CN) is known to be involved in many biological processes, particularly, the immune response mechanism in many invertebrates. In this study, we characterized both HcCNA and HcCNB genes in Haliotis ersicolor , documented their expression in many tissues, and discerned their function as immune responsive genes against Vibrio parahaemolyticus infection. Similar to other mollusk CNs, the HcCNA gene lacked a proline-rich domain and comprised only one isoform of its catalytic unit, in contrast to CNs found in mammals. HcCNB was highly conserved in both sequence and domain architecture. Quantitative PCR and in situ hybridization revealed that the genes were broadly expressed and were not restricted to tissues traditionally associated with immune function. Upon infection of H. ersicolor with V. parahaemolyticus (a bacteria that causes serious disease in crustaceans and mollusks), both HcCNA and HcCNB genes were highly up-regulated at the early phase of bacterial infection. HcCNB was expressed significantly higher than HcCNA in response to bacterial challenge, suggesting its independent or more rapid response to bacterial infection. Together, the two CN genes are unique in their gene structure (particular HcCNA ) and distribution in mollusk species and likely function as immune responsive genes along with many other genes that are enhanced in the early phase of V. parahaemolyticus infection in abalone.
Publisher: Springer Science and Business Media LLC
Date: 19-10-2019
DOI: 10.1186/S13227-019-0140-7
Abstract: Eyes have evolved and been lost multiple times during animal evolution, however, the process of eye loss has only been reconstructed in a few cases. Mollusks exhibit eyes as varied as the octopod camera eye or the gastropod cup eye and are ideal systems for studying the evolution of eyes, photoreceptors, and opsins. Here, we identify genes related to photoreceptor formation and function in an eyeless conchiferan mollusk, the scaphopod Antalis entalis , and investigate their spatial and temporal expression patterns during development. Our study reveals that the scaphopod early mid-stage trochophore larva has putative photoreceptors in a similar location and with a similar gene expression profile as the trochophore of polyplacophoran mollusks. The apical and post-trochal putative photoreceptors appear to co-express go - opsin , six1 / 2 , myoV , and eya , while expression domains in the posterior foot and pavilion (posterior mantle opening) show co-expression of several other candidate genes but not go - opsin . Sequence analysis reveals that the scaphopod Go-opsin amino acid sequence lacks the functionally important lysine (K296 Schiff base) in the retinal-binding domain, but has not accumulated nonsense mutations and still exhibits the canonical G-protein activation domain. The scaphopod Go-opsin sequence reported here is the only known ex le of a bilaterian opsin that lacks lysine K296 in the retinal-binding domain. Although this may render the Go-opsin unable to detect light, the protein may still perform sensory functions. The location, innervation, development, and gene expression profiles of the scaphopod and polyplacophoran apical and post-trochal photoreceptors suggest that they are homologous, even though the scaphopod post-trochal photoreceptors have degenerated. This indicates that post-trochal eyes are not a polyplacophoran apomorphy but likely a molluscan synapomorphy lost in other mollusks. Scaphopod eye degeneration is probably a result of the transition to an infaunal life history and is reflected in the likely functional degeneration of Go-opsin, the loss of photoreceptor shielding pigments, and the scarce expression of genes involved in phototransduction and eye development. Our results emphasize the importance of studying a phylogenetically broad range of taxa to infer the mechanisms and direction of body plan evolution.
Publisher: Springer Science and Business Media LLC
Date: 27-10-2022
DOI: 10.1186/S12864-022-08931-9
Abstract: Crustose coralline algae (CCA) are calcifying red macroalgae that play important ecological roles including stabilisation of reef frameworks and provision of settlement cues for a range of marine invertebrates. Previous research into the responses of CCA to ocean warming (OW) and ocean acidification (OA) have found magnitude of effect to be species-specific. Response to OW and OA could be linked to ergent underlying molecular processes across species. Here we show Sporolithon durum , a species that exhibits low sensitivity to climate stressors, had little change in metabolic performance and did not significantly alter the expression of any genes when exposed to temperature and pH perturbations. In contrast, Porolithon onkodes , a major coral reef builder, reduced photosynthetic rates and had a labile transcriptomic response with over 400 significantly differentially expressed genes, with differential regulation of genes relating to physiological processes such as carbon acquisition and metabolism. The differential gene expression detected in P. onkodes implicates possible key metabolic pathways, including the pentose phosphate pathway, in the stress response of this species. We suggest S. durum is more resistant to OW and OA than P. onkodes , which demonstrated a high sensitivity to climate stressors and may have limited ability for acclimatisation. Understanding changes in gene expression in relation to physiological processes of CCA could help us understand and predict how different species will respond to, and persist in, future ocean conditions predicted for 2100.
Publisher: Springer Science and Business Media LLC
Date: 12-2018
Publisher: Springer Science and Business Media LLC
Date: 10-10-2006
Abstract: To understand the evolution of animals it is essential to have taxon s ling across a representative spread of the animal kingdom. With the recent rearrangement of most of the Bilateria into three major clades (Ecdysozoa, Lophotrochozoa and Deuterostomia) it has become clear that the Lophotrochozoa are relatively poorly represented in our knowledge of animal development, compared to the Ecdysozoa and Deuterostomia. We aim to contribute towards redressing this balance with data on the development of the muscular, nervous and ciliary systems of the annelid Pomatoceros lamarckii (Serpulidae). We compare our data with other lophotrochozoans. P. lamarckii develops locomotory and feeding structures that enable it to become a swimming, planktotrophic larva within 24 hours. Formation of the trochophore includes development of a prototroch, metatroch and neurotroch, development of apical and posterior nervous elements at similar times, and development of musculature around the ciliary bands and digestive tract prior to development of any body wall muscles. The adult nervous and muscular systems are essentially preformed in the late larva. Interestingly, the muscular systems of the larvae and juvenile worms do not include the circular muscles of the body wall, which are considered to be plesiomorphic for annelids, although the possibility that circular muscles develop after these stages cannot be ruled out at this point. A comparison between polychaetes shows variability in the timing (heterochrony) of development of body wall muscles and elements of the nervous system. These heterochronies are one route for evolution of different life history strategies, such as adaptations to feeding requirements.
Publisher: Frontiers Media SA
Date: 24-09-2021
DOI: 10.3389/FMARS.2021.752949
Abstract: Many pigments, such as melanins, are widely distributed throughout the animal kingdom. Others have arisen as novelties in particular lineages, for ex le, the Green Fluorescent Protein (GFP) found in cnidarians. While GFPs, widely used as fluorescent tags in biomedical research, are the most famous cnidarian ex le, other novel proteins have also been identified within this phylum. A blue protein that contains a Kringle (KR) domain inserted within a Frizzled cysteine-rich domain (Fz-CRD) was previously described from the jellyfish Rhizostoma pulmo (named rpulFKz1), however little is known about this pigment’s evolution or distribution among cnidarians. We performed a systematic search for homologs of this protein in published genomes and transcriptomes of 93 cnidarians. Phylogenetic analyses revealed eight predicted proteins that possess both domains in the same arrangement and that fall within the same clade as rpulFKz1. The sequence of one of these proteins contains motifs that match sequenced peptides of Cassio Blue, the blue pigment from Cassiopea xamachana . Another one of these proteins belongs to Stomolophus meleagris , and chemical studies on blue pigments that may occur in this genus have shown similarities to rpulFKz1 and Cassio Blue. Therefore, we hypothesize that the eight rpulFKz1 homologs identified are also pigment precursors. All precursors identified were exclusive to jellyfish in the order Rhizostomeae, so we herein name this new pigment family “rhizostomins.” Not all rhizostomes analyzed are blue, however, so these rhizostomin proteins may also be responsible for other colors, or perform other biochemical and biophysical roles. Previous studies have hypothesized that cnidarian pigments are photoprotective, and this study serves as basis for future investigations not only on the function of rhizostomins, but also on potential biotechnological applications for these proteins.
Publisher: Springer Science and Business Media LLC
Date: 22-11-2006
Abstract: Instructions to fabricate mineralized structures with distinct nanoscale architectures, such as seashells and coral and vertebrate skeletons, are encoded in the genomes of a wide variety of animals. In mollusks, the mantle is responsible for the extracellular production of the shell, directing the ordered biomineralization of CaCO 3 and the deposition of architectural and color patterns. The evolutionary origins of the ability to synthesize calcified structures across various metazoan taxa remain obscure, with only a small number of protein families identified from molluskan shells. The recent sequencing of a wide range of metazoan genomes coupled with the analysis of gene expression in non-model animals has allowed us to investigate the evolution and process of biomineralization in gastropod mollusks. Here we show that over 25% of the genes expressed in the mantle of the vetigastropod Haliotis asinina encode secreted proteins, indicating that hundreds of proteins are likely to be contributing to shell fabrication and patterning. Almost 85% of the secretome encodes novel proteins remarkably, only 19% of these have identifiable homologues in the full genome of the patellogastropod Lottia scutum . The spatial expression profiles of mantle genes that belong to the secretome is restricted to discrete mantle zones, with each zone responsible for the fabrication of one of the structural layers of the shell. Patterned expression of a subset of genes along the length of the mantle is indicative of roles in shell ornamentation. For ex le, Has-sometsuke maps precisely to pigmentation patterns in the shell, providing the first case of a gene product to be involved in molluskan shell pigmentation. We also describe the expression of two novel genes involved in nacre (mother of pearl) deposition. The unexpected complexity and evolvability of this secretome and the modular design of the molluskan mantle enables ersification of shell strength and design, and as such must contribute to the variety of adaptive architectures and colors found in mollusk shells. The composition of this novel mantle-specific secretome suggests that there are significant molecular differences in the ways in which gastropods synthesize their shells.
Publisher: Springer Science and Business Media LLC
Date: 30-08-2019
DOI: 10.1038/S41598-019-48283-1
Abstract: Crustose coralline algae (CCA) are calcifying red macroalgae that reef build in their own right and perform essential ecosystem functions on coral reefs worldwide. Despite their importance, limited genetic information exists for this algal group. De novo transcriptomes were compiled for four species of common tropical CCA using RNA-seq. Sequencing generated between 66 and 87 million raw reads. Transcriptomes were assembled, redundant contigs removed, and remaining contigs were annotated using Trinotate. Protein orthology analysis was conducted between CCA species and two noncalcifying red algae species from NCBI that have published genomes and transcriptomes, and 978 orthologous protein groups were found to be uniquely shared amongst CCA. Functional enrichment analysis of these ‘CCA-specific’ proteins showed a higher than expected number of sequences from categories relating to regulation of biological and cellular processes, such as actin related proteins, heat shock proteins, and adhesion proteins. Some proteins found within these enriched categories, i.e. actin and GH18, have been implicated in calcification in other taxa, and are thus candidates for involvement in CCA calcification. This study provides the first comprehensive investigation of gene content in these species, offering insights not only into the evolution of coralline algae but also of the Rhodophyta more broadly.
Publisher: Springer Science and Business Media LLC
Date: 07-06-2016
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.ACTBIO.2014.03.031
Abstract: Tyrosinase is a copper-containing enzyme that mediates the hydroxylation of monophenols and oxidation of o-diphenols to o-quinones. This enzyme is involved in a variety of biological processes, including pigment production, innate immunity, wound healing, and exoskeleton fabrication and hardening (e.g. arthropod skeleton and mollusc shell). Here we show that the tyrosinase gene family has undergone large expansions in pearl oysters (Pinctada spp.) and the Pacific oyster (Crassostrea gigas). Phylogenetic analysis reveals that pearl oysters possess at least four tyrosinase genes that are not present in the Pacific oyster. Likewise, C. gigas has multiple tyrosinase genes that are not orthologous to the Pinctada genes, indicating that this gene family has expanded independently in these bivalve lineages. Many of the tyrosinase genes in these bivalves are expressed at relatively high levels in the mantle, the organ responsible for shell fabrication. Detailed comparisons of tyrosinase gene expression in different regions of the mantle in two closely related pearl oysters, P. maxima and P. margaritifera, reveals that recently evolved orthologous tyrosinase genes can have markedly different expression profiles. The expansion of tyrosinase genes in these oysters and their co-option into the mantle's gene regulatory network is consistent with mollusc shell formation being underpinned by a rapidly evolving transcriptome.
Publisher: Springer Science and Business Media LLC
Date: 02-09-2014
Publisher: Oxford University Press (OUP)
Date: 04-01-2017
Publisher: Oxford University Press (OUP)
Date: 04-07-2011
Abstract: Genes with the homeobox motif are crucial in developmental biology and widely implicated in the evolution of development. The Antennapedia (ANTP)-class is one of the two major classes of animal homeobox genes, and includes the Hox genes, renowned for their role in patterning the anterior-posterior axis of animals. The origin and evolution of the ANTP-class genes are a matter of some debate. A principal guiding hypothesis has been the existence of an ancient gene Mega-cluster deep in animal ancestry. This hypothesis was largely established from linkage data from chordates, and the Mega-cluster hypothesis remains to be seriously tested in protostomes. We have thus mapped ANTP-class homeobox genes to the chromosome level in a lophotrochozoan protostome. Our comparison of gene organization in Platynereis dumerilii and chordates indicates that the Mega-cluster, if it did exist, had already been broken up onto four chromosomes by the time of the protostome-deuterostome ancestor (PDA). These results not only elucidate an aspect of the genome organization of the PDA but also reveal high levels of macrosynteny between P. dumerilii and chordates. This implies a very low rate of interchromosomal genome rearrangement in the lineages leading to P. dumerilii and the chordate ancestor since the time of the PDA.
Publisher: Informa UK Limited
Date: 26-12-2018
Publisher: Springer Science and Business Media LLC
Date: 31-01-2011
Publisher: Cold Spring Harbor Laboratory
Date: 22-05-2020
DOI: 10.1101/2020.05.19.102897
Abstract: Molluscs biomineralize structures that vary in composition, form, and function, prompting questions about the genetic mechanisms responsible for their production and the evolution of these mechanisms. Chitons (Mollusca, Polyplacophora) are a promising system for studies of biomineralization because they build a range of calcified structures including shell plates and spine- or scale-like sclerites. Chitons also harden the calcified teeth of their rasp-like radula with a coat of iron (as magnetite). Here we present the genome of the West Indian fuzzy chiton Acanthopleura granulata , the first from any aculiferan mollusc. The A. granulata genome contains homologs of many biomineralization genes identified previously in conchiferan molluscs. We expected chitons to lack genes previously identified from pathways conchiferans use to make biominerals like calcite and nacre because chitons do not use these materials in their shells. Surprisingly, the A. granulata genome has homologs of many of these genes, suggesting that the ancestral mollusc had a more erse biomineralization toolkit than expected. The A. granulata genome has features that may be specialized for iron biomineralization, including a higher proportion of genes regulated directly by iron than other molluscs. A. granulata also produces two isoforms of soma-like ferritin: one is regulated by iron and similar in sequence to the soma-like ferritins of other molluscs, and the other is constitutively translated and is not found in other molluscs. The A. granulata genome is a resource for future studies of molluscan evolution and biomineralization. Chitons are molluscs that make shell plates, spine- or scale-like sclerites, and iron-coated teeth. Currently, all molluscs with sequenced genomes lie within one major clade (Conchifera). Sequencing the genome of a representative from the other major clade (Aculifera) helps us learn about the origins and evolution of molluscan traits. The genome of the West Indian Fuzzy Chiton, Acanthopleura granulata , reveals chitons have homologs of many genes other molluscs use to make shells, suggesting all molluscs share some shell-making pathways. The genome of A. granulata has more genes that may be regulated directly by iron than other molluscs, and chitons produce a unique isoform of a major iron-transport protein (ferritin), suggesting that chitons have genomic specializations that contribute to their production of iron-coated teeth.
Publisher: Elsevier BV
Date: 2022
Publisher: Springer Science and Business Media LLC
Date: 16-08-2011
Abstract: Dlx (Distal-less) genes have various developmental roles and are widespread throughout the animal kingdom, usually occurring as single copy genes in non-chordates and as multiple copies in most chordate genomes. While the genomic arrangement and function of these genes is well known in vertebrates and arthropods, information about Dlx genes in other organisms is scarce. We investigate the presence of Dlx genes in several annelid species and examine Dlx gene expression in the polychaete Pomatoceros lamarckii . Two Dlx genes are present in P. lamarckii, Capitella teleta and Helobdella robusta . The C. teleta Dlx genes are closely linked in an inverted tail-to-tail orientation, reminiscent of the arrangement of vertebrate Dlx pairs, and gene conversion appears to have had a role in their evolution. The H. robusta Dlx genes, however, are not on the same genomic scaffold and display ergent sequences, while, if the P. lamarckii genes are linked in a tail-to-tail orientation they are a minimum of 41 kilobases apart and show no sign of gene conversion. No expression in P. lamarckii appendage development has been observed, which conflicts with the supposed conserved role of these genes in animal appendage development. These Dlx duplications do not appear to be annelid-wide, as the polychaete Platynereis dumerilii likely possesses only one Dlx gene. On the basis of the currently accepted annelid phylogeny, we hypothesise that one Dlx duplication occurred in the annelid lineage after the ergence of P. dumerilii from the other lineages and these duplicates then had varied evolutionary fates in different species. We also propose that the ancestral role of Dlx genes is not related to appendage development.
Publisher: Wiley
Date: 28-11-2014
DOI: 10.1002/DVG.22840
Abstract: The organization of echinoderm Hox clusters is of interest due to the role that Hox genes play in deuterostome development and body plan organization, and the unique gene order of the Hox complex in the sea urchin Strongylocentrotus purpuratus, which has been linked to the unique development of the axial region. Here, it has been reported that the Hox and ParaHox clusters of Acanthaster planci, a corallivorous starfish found in the Pacific and Indian oceans, generally resembles the chordate and hemichordate clusters. The A. planci Hox cluster shared with sea urchins the loss of one of the medial Hox genes, even-skipped (Evx) at the anterior of the cluster, as well as organization of the posterior Hox genes.
Publisher: Springer Science and Business Media LLC
Date: 11-11-2010
Publisher: Springer Science and Business Media LLC
Date: 24-01-2018
DOI: 10.1007/S10886-018-0926-4
Abstract: Within the Phylum Echinodermata, the class Asteroidea, commonly known as starfish and sea stars, encompasses a large number of benthos inhabiting genera and species with various feeding modalities including herbivores, carnivores, omnivores and detritivores. The Asteroidea rely on chemosensation throughout their life histories including hunting prey, avoiding or deterring predators, in the formation of spawning aggregations, synchronizing gamete release and targeting appropriate locations for larval settlement. The identities of many of the chemical stimuli that mediate these physiological and behavioural processes remain unresolved even though evidence indicates they play pivotal roles in the functionality of benthic communities. Aspects of chemosensation, as well as putative chemically-mediated behaviours and the molecular mechanisms of chemoreception, within the Asteroidea are reviewed here, with particular reference to the coral reef pest the Crown-of-Thorns starfish Acanthaster planci species complex, in the context of mitigation of population outbreaks.
Publisher: CSIRO Publishing
Date: 19-10-2022
DOI: 10.1071/MF22176
Abstract: Context Alien freshwater snails pose a substantial risk to Australian native aquatic biota. Aims This study aims to determine the thermal and salinity ranges of two introduced species within Australia, Pomacea sp. and Anentome sp., to facilitate predictions of their potential geographic range should they become widely established. Methods Laboratory tests were conducted to assess behavioural responses of snails to altered temperature or salinity after different acclimation regimes. Key results After acclimation at 25°C, Pomacea sp. had a median activity range of 13.5–38°C and Anentome sp. of 12–38.5°C. Higher acclimation temperatures produced observable effects, whereas lower acclimation temperatures did not. Salinity tolerances differed, with Pomacea sp. remaining active at up to 8 parts per thousand (ppt) (after acclimation at 25°C), with acclimation at 20°C resulting in a lower salinity tolerance. By contrast, Anentome sp. snails were active at up to 5 ppt after low salinity acclimation, demonstrating enhanced salinity tolerance compared with non-salinity acclimations. Conclusions These results showed that both snails are capable of surviving temperatures and salinities that would allow invasion into subtropical and warm-temperate Australian aquatic systems. Implications Free from the constraints of natural predators, competitors, and parasites, these snails should be of great concern to biosecurity agencies in Australia.
Publisher: Public Library of Science (PLoS)
Date: 25-10-2018
Publisher: Springer Science and Business Media LLC
Date: 2014
Publisher: Elsevier BV
Date: 09-2023
Publisher: Oxford University Press (OUP)
Date: 13-11-2009
Abstract: The capacity to biomineralize is closely linked to the rapid expansion of animal life during the early Cambrian, with many skeletonized phyla first appearing in the fossil record at this time. The appearance of disparate molluscan forms during this period leaves open the possibility that shells evolved independently and in parallel in at least some groups. To test this proposition and gain insight into the evolution of structural genes that contribute to shell fabrication, we compared genes expressed in nacre (mother-of-pearl) forming cells in the mantle of the bivalve Pinctada maxima and the gastropod Haliotis asinina. Despite both species having highly lustrous nacre, we find extensive differences in these expressed gene sets. Following the removal of housekeeping genes, less than 10% of all gene clusters are shared between these molluscs, with some being conserved biomineralization genes that are also found in deuterostomes. These differences extend to secreted proteins that may localize to the organic shell matrix, with less than 15% of this secretome being shared. Despite these differences, H. asinina and P. maxima both secrete proteins with repetitive low-complexity domains (RLCDs). Pinctada maxima RLCD proteins-for ex le, the shematrins-are predominated by silk/fibroin-like domains, which are absent from the H. asinina data set. Comparisons of shematrin genes across three species of Pinctada indicate that this gene family has undergone extensive ergent evolution within pearl oysters. We also detect fundamental bivalve-gastropod differences in extracellular matrix proteins involved in mollusc-shell formation. Pinctada maxima expresses a chitin synthase at high levels and several chitin deacetylation genes, whereas only one protein involved in chitin interactions is present in the H. asinina data set, suggesting that the organic matrix on which calcification proceeds differs fundamentally between these species. Large-scale differences in genes expressed in nacre-forming cells of Pinctada and Haliotis are compatible with the hypothesis that gastropod and bivalve nacre is the result of convergent evolution. The expression of novel biomineralizing RLCD proteins in each of these two molluscs and, interestingly, sea urchins suggests that the evolution of such structural proteins has occurred independently multiple times in the Metazoa.
Publisher: Wiley
Date: 29-06-2016
DOI: 10.1002/PSC.2887
Abstract: Abalone (Haliotis) undergoes a period of reproductive maturation, followed by the synchronous release of gametes, called broadcast spawning. Field and laboratory studies have shown that the tropical species Haliotis asinina undergoes a two-week spawning cycle, thus providing an excellent opportunity to investigate the presence of endogenous spawning-associated peptides. In female H. asinina, we have isolated a peptide (5145 Da) whose relative abundance in hemolymph increases substantially just prior to spawning and is still detected using reverse-phase high-performance liquid chromatography chromatograms up to 1-day post-spawn. We have isolated this peptide from female hemolymph as well as s les prepared from the gravid female gonad, and demonstrated through comparative sequence analysis that it contains features characteristic of Kazal-type proteinase inhibitors (KPIs). Has-KPI is expressed specifically within the gonad of adult females. A recombinant Has-KPI was generated using a yeast expression system. The recombinant Has-KPI does not induce premature spawning of female H. asinina when administered intramuscularly. However it displays homomeric aggregations and interaction with at least one mollusc-type neuropeptide (LRDFVamide), suggesting a role for it in regulating neuropeptide endocrine communication. This research provides new understanding of a peptide that can regulate reproductive processes in female abalone, which has the potential to lead to the development of greater control over abalone spawning. The findings also highlight the need to further explore abalone reproduction to clearly define a role for novel spawning-associated peptide in sexual maturation and spawning. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd.
Publisher: Frontiers Media SA
Date: 23-06-2022
DOI: 10.3389/FMARS.2022.873768
Abstract: Oysters are ecosystem engineers that form biogenic reef habitats in shallow coastal and estuarine waters and provide important ecosystem services. Widespread global declines have triggered a world-wide restoration movement, however a paucity of information on tropical oyster reefs has resulted in their exclusion from existing global assessments and, consequently, restoration. In this review we quantified the known global ersity of native reef-building oysters to compare ersity between temperate and tropical regions and assessed historic oyster reef presence and declines using two tropical case studies. We then summarised the biology, ecology, and benefits of tropical oyster reefs, which have four functional differences to temperate reefs: 1) the ersity of reef-building oysters is over four times higher in tropical than in temperate regions 2) tropical reef-building oysters can have continuous spatfall throughout the year whereas temperate species have a defined season 3) tropical reef-building oysters are generally faster growing than temperate reef-building oysters and 4) tropical oysters commonly create mixed-species oyster reefs whereas temperate oyster reefs are generally formed by a single oyster species. There is evidence of unsustainable and destructive harvesting that has resulted in the decline of tropical oyster reefs, and these reefs should therefore be included in restoration efforts. We highlight knowledge gaps that can guide future research to develop important foundational information that will remove barriers to tropical oyster reef restoration.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Carmel McDougall.