The Experts below are selected from a list of 12222 Experts worldwide ranked by ideXlab platform
Kirsten Benkendorff - One of the best experts on this subject based on the ideXlab platform.
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Review of anti-inflammatory, immune-modulatory and wound healing properties of molluscs
ePublications@SCU, 2017Co-Authors: Ahmad, Tarek B, Liu Lei, Kotiw Michael, Kirsten BenkendorffAbstract:This review focuses on traditional and contemporary anti-inflammatory uses of mollusc-derived products summarising all the in vitro, in vivo and human clinical trials that have tested the anti-inflammatory activity of Molluscan natural products. Inflammatory conditions, burns and wounds have been an ongoing concern for human health since the early era of civilisation. Many texts from ancient medicine have recorded the symptoms, signs and treatments for these conditions. Natural treatments are well-documented in traditional European medicine, Traditional Chinese Medicine (TCM), Siddha and ancient Mediterranean and African traditional medicine and include a surprisingly large number of Molluscan species. Methods: An extensive review of the Materia Medica and scientific literature was undertaken using key word searches for mollusc and anti-inflammatory or immunomodulatory or wound healing . Results: Molluscs have been used in ethnomedicine by many traditional cultures to treat different aspects of inflammatory conditions. We found 104 different anti-inflammatory preparations from a variety of Molluscan species, of which 70 were from the well-documented Traditional Chinese Medicine (TCM). This traditional use of molluscs has driven the testing for inflammatory activity in extracts from some species in the phylum Mollusca, with 20 in vitro studies, 40 in vivo animal studies and 14 human clinical trials performed to substantiate the anti-inflammatory and wound healing activity of molluscs. Some of these studies have led to the approval of mollusc-derived products to be used as over-the-counter (OTC) nutraceuticals, like Lyprinol® and Biolane™ from the New Zealand green lipped mussel Perna canaliculus. Conclusion: Natural products provide important leads for the development of pharmaceuticals, including anti-inflammatory agents. Only a small proportion of the Molluscan traditional medicines have been tested to confirm their anti-inflammatory activity and most screening studies have tested crude extracts from molluscs without any chemical characterisation. This highlights the need for further research to strategically identify the anti-inflammatory compounds in Molluscan medicines to provide leads for novel anti-inflammatory drugs in the future
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Molluscan biological and chemical diversity secondary metabolites and medicinal resources produced by marine molluscs
Biological Reviews, 2010Co-Authors: Kirsten BenkendorffAbstract:The phylum Mollusca represents an enormous diversity of species with eight distinct classes. This review provides a taxonomic breakdown of the published research on marine Molluscan natural products and the medicinal products currently derived from molluscs, in order to identify priority targets and strategies for future research. Some marine gastropods and bivalves have been of great interest to natural products chemists, yielding a diversity of chemical classes and several drug leads currently in clinical trials. Molluscs also feature prominently in a broad range of traditional natural medicines, although the active ingredients in the taxa involved are typically unknown. Overall secondary metabolites have only been investigated from a tiny proportion (<1%) of Molluscan species. At the class level, the number of species subject to chemical studies mirrors species richness and our relative knowledge of the biology of different taxa. The majority of Molluscan natural products research is focused within one of the major groups of gastropods, the opisthobranchs (a subgroup of Heterobranchia), which are primarily comprised of soft-bodied marine molluscs. Conversely, most Molluscan medicines are derived from shelled gastropods and bivalves. The complete disregard for several minor classes of molluscs is unjustified based on their evolutionary history and unique life styles, which may have led to novel pathways for secondary metabolism. The Polyplacophora, in particular, have been identified as worthy of future investigation given their use in traditional South African medicines and their abundance in littoral ecosystems. As bioactive compounds are not always constitutively expressed in molluscs, future research should be targeted towards biosynthetic organs and inducible defence reactions for specific medicinal applications. Given the lack of an acquired immune system, the use of bioactive secondary metabolites is likely to be ubiquitous throughout the Mollusca and broadening the search field may uncover interesting novel chemistry.
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free fatty acids and sterols in the benthic spawn of aquatic molluscs and their associated antimicrobial properties
Journal of Experimental Marine Biology and Ecology, 2005Co-Authors: Kirsten Benkendorff, Andrew R Davis, Cary N Rogers, John B BremnerAbstract:The free lipid content of extracts from the spawn of 17 molluscs were analysed by gas chromatography/mass spectrometry. These extracts encompass the encapsulated embryos and extraembryonic structures from benthic gelatinous egg masses and leathery egg capsules covering five taxonomic groups. Palmitic and stearic acids were the dominant saturated fatty acids and oleic acid was the principal unsaturated acid found in the spawn. Cholesterol was the dominant sterol and the only sterol found in the spawn from every species. Extracts from gelatinous egg masses were found to contain proportionally more fatty acids compared to leathery egg capsules. No unsaturated fatty acids were found in any of the leathery egg capsules, including five neogastropods and one littorinimorph. Unsaturated fatty acids were present in all of the gelatinous egg masses, including two other littorinimorphs. This is the first study to demonstrate that unsaturated fatty acids possess significant bacteriolytic activity against four aquatic pathogens. Encapsulated Anaspidea egg masses contain relatively high concentrations of these unsaturated fatty acids and a lipid mixture modeled on these extracts was strongly bacteriolytic at concentrations down to 0.0001 mg/ml. By comparison, lipid mixtures modeled on extracts from the spawn of four other Molluscan taxa with higher proportions of saturated fatty acid and cholesterol, were only partially active against some of the bacteria at 0.1 mg/ml. Thus, unsaturated fatty acids could explain the antimicrobial activity previously reported in lipid extracts of some, but not most, Molluscan spawn. MDS ordination and ANOSIM revealed significant taxonomic differences in the composition of free lipids from Molluscan spawn, suggesting that lipid analyses may be useful in future systematic studies of the Mollusca.
Leonid L Moroz - One of the best experts on this subject based on the ideXlab platform.
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phylogenomics reveals deep Molluscan relationships
Nature, 2011Co-Authors: Kevin M Kocot, Johanna T Cannon, Christiane Todt, Mathew R Citarella, Andrea B Kohn, Achim Meyer, Scott R Santos, Christoffer Schander, Leonid L MorozAbstract:Evolutionary relationships among the eight major lineages of Mollusca have remained unresolved despite their diversity and importance. Previous investigations of Molluscan phylogeny, based primarily on nuclear ribosomal gene sequences or morphological data, have been unsuccessful at elucidating these relationships. Recently, phylogenomic studies using dozens to hundreds of genes have greatly improved our understanding of deep animal relationships. However, limited genomic resources spanning Molluscan diversity has prevented use of a phylogenomic approach. Here we use transcriptome and genome data from all major lineages (except Monoplacophora) and recover a well-supported topology for Mollusca. Our results strongly support the Aculifera hypothesis placing Polyplacophora (chitons) in a clade with a monophyletic Aplacophora (worm-like molluscs). Additionally, within Conchifera, a sister-taxon relationship between Gastropoda and Bivalvia is supported. This grouping has received little consideration and contains most (>95%) Molluscan species. Thus we propose the node-based name PleistoMollusca. In light of these results, we examined the evolution of morphological characters and found support for advanced cephalization and shells as possibly having multiple origins within Mollusca.
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From Polyplacophora to Cephalopoda: comparative analysis of nitric oxide signalling in Mollusca.
Acta biologica Hungarica, 1995Co-Authors: Leonid L Moroz, Rhanor GilletteAbstract:The distribution of putative nitric oxide synthase (NOS)-containing cells has been analysed using NADPH-d histochemistry in the CNS and peripheral tissues in more than 2D ecologically and systematically different Molluscan genera representing 3 main classes of the phylum Mollusca: Polyplacophora (Lepidopleurus, Lepidozona, Katharina), Gastropoda (Littorina, Lymnaea, Aplexa, Physa, Planorbarius, Planorbis, Helisoma, Biomphalaria, Helix, Limax, Cepaea, Bulla, Aplysia, Phyllaplysia, Philine, Pleurobranchea, Tritonia, Armina, Flabellina, Cadlina) and Cephalopoda (Octopus, Sepia, Rossia, Loligo). Several species were used for more detailed immunohistochemical, biochemical, biophysical and physiological studies to further assay of NOS activity and to analyse functional roles of nitric oxide (NO) in these animals. The main conclusions of our comparative analysis and literature survey can be summarised as following: (i) There is strong evidence for the presence of NO-dependent signalling pathways in different Molluscan species. (ii) We hypothesise that a general tendency in the evolution of NADPH-d-reactive cells in Mollusca is a migration of nitrergic function from periphery to the CNS. Also, different isoforms of NOS appear to be present in any one species. (iii) One of the main functional targets of NO signalling is the feeding system. However, there are obvious differences between predators (many labelled central motoneurons) and herbivorous species (many labelled peripheral putative sensory cells) as well as between land/freshwater and marine animals. Nevertheless, in all species tested NO-activated feeding-like motor patterns in the buccal ganglia. Additional functional and cellular targets for NO in molluscs are also considered. We briefly review neuromodulatory mechanisms of NO action and we consider molluscs as useful model systems for investigations of the roles of NO.
Baozhong Liu - One of the best experts on this subject based on the ideXlab platform.
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dorsoventral decoupling of hox gene expression underpins the diversification of molluscs
Proceedings of the National Academy of Sciences of the United States of America, 2020Co-Authors: Pin Huan, Qian Wang, Sujian Tan, Baozhong LiuAbstract:In contrast to the Hox genes in arthropods and vertebrates, those in molluscs show diverse expression patterns with differences reported among lineages. Here, we investigate 2 phylogenetically distant molluscs, a gastropod and a polyplacophoran, and show that the Hox expression in both species can be divided into 2 categories. The Hox expression in the ventral ectoderm generally shows a canonical staggered pattern comparable to the patterns of other bilaterians and likely contributes to ventral patterning, such as neurogenesis. The other category of Hox expression on the dorsal side is strongly correlated with shell formation and exhibits lineage-specific characteristics in each class of mollusc. This generalized model of decoupled dorsoventral Hox expression is compatible with known Hox expression data from other Molluscan lineages and may represent a key characteristic of Molluscan Hox expression. These results support the concept of widespread staggered Hox expression in Mollusca and reveal aspects that may be related to the evolutionary diversification of molluscs. We propose that dorsoventral decoupling of Hox expression allowed lineage-specific dorsal and ventral patterning, which may have facilitated the evolution of diverse body plans in different Molluscan lineages.
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dorsoventral dissociation of hox gene expression underpins the diversification of molluscs
bioRxiv, 2019Co-Authors: Pin Huan, Qian Wang, Sujian Tan, Baozhong LiuAbstract:Abstract Unlike the Hox genes in arthropods and vertebrates, those in molluscs show diverse expression patterns and, with some exceptions, have generally been described as lacking the canonical staggered pattern along the anterior-posterior (AP) axis. This difference is unexpected given that almost all molluscs share highly conserved early development. Here, we show that Molluscan Hox expression can undergo dynamic changes, which may explain why previous research observed different expression patterns. Moreover, we reveal that a key character of Molluscan Hox expression is that the dorsal and ventral expression is dissociated. We then deduce a generalized Molluscan Hox expression model, including conserved staggered Hox expression in the neuroectoderm on the ventral side and lineage-specific dorsal expression that strongly correlates with shell formation. This generalized model clarifies a long-standing debate over whether molluscs possess staggered Hox expression and it can be used to explain the diversification of molluscs. In this scenario, the dorsoventral dissociation of Hox expression allows lineage-specific dorsal and ventral patterning in different clades, which may have permitted the evolution of diverse body plans in different Molluscan clades.
Gerhard Steiner - One of the best experts on this subject based on the ideXlab platform.
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the testaria concept polyplacophora conchifera updated
Journal of Natural History, 2014Co-Authors: Luitfried V Salviniplawen, Gerhard SteinerAbstract:Mollusca is the second most speciose phylum of animals and includes a high organizational diversity grouped in eight classes, with the gastropods and bivalves being most familiar. The phylogenetic relationships among the three aculiferan Molluscan classes Solenogastres (Neomeniomorpha), Caudofoveata (Chaetodermomorpha) and Polyplacophora (Placophora, chitons, Loricata), as well as the sister-group relationship to Conchifera (all other molluscs) are still under discussion. On one side, the three aculiferan groups are regarded as a monophyletic clade, Aculifera, contrasted with its sister taxon Conchifera (Aculifera concept). Recent molecular-phylogenomic analyses appear to support this hypothesis. Here we point out the plesiomorphic nature of many morphological similarities among the aculiferan taxa and in relation to Conchifera. On the other side, a complex of morphological synapomorphies support Recent Polyplacophora as sister group to Conchifera (Testaria concept). The supposed monophyletic characters f...
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the complete sequences and gene organisation of the mitochondrial genomes of the heterodont bivalves acanthocardia tuberculata and hiatella arctica and the first record for a putative atpase subunit 8 gene in marine bivalves
Frontiers in Zoology, 2006Co-Authors: Hermann Dreyer, Gerhard SteinerAbstract:Background: Mitochondrial (mt) gene arrangement is highly variable among molluscs and especially among bivalves. Of the 30 complete Molluscan mt-genomes published to date, only one is of a heterodont bivalve, although this is the most diverse taxon in terms of species numbers. We determined the complete sequence of the mitochondrial genomes of Acanthocardia tuberculata and Hiatella arctica, (Mollusca, Bivalvia, Heterodonta) and describe their gene contents and genome organisations to assess the variability of these features among the Bivalvia and their value for phylogenetic inference. Results: The size of the mt-genome in Acanthocardia tuberculata is 16.104 basepairs (bp), and in Hiatella arctica 18.244 bp. The Acanthocardia mt-genome contains 12 of the typical protein coding genes, lacking the Atpase subunit 8 (atp8) gene, as all published marine bivalves. In contrast, a complete atp8 gene is present in Hiatella arctica. In addition, we found a putative truncated atp8 gene when re-annotating the mt-genome of Venerupis philippinarum. Both mt-genomes reported here encode all genes on the same strand and have an additional trnM. In Acanthocardia several large non-coding regions are present. One of these contains 3.5 nearly identical copies of a 167 bp motive. In Hiatella, the 3' end of the NADH dehydrogenase subunit (nad)6 gene is duplicated together with the adjacent non-coding region. The gene arrangement of Hiatella is markedly different from all other known Molluscan mt-genomes, that of Acanthocardia shows few identities with the Venerupis philippinarum. Phylogenetic analyses on amino acid and nucleotide levels robustly support the Heterodonta and the sister group relationship of Acanthocardia and Venerupis. Monophyletic Bivalvia are resolved only by a Bayesian inference of the nucleotide data set. In all other analyses the two unionid species, being to only ones with genes located on both strands, do not group with the remaining bivalves. Conclusion: The two mt-genomes reported here add to and underline the high variability of gene order and presence of duplications in bivalve and Molluscan taxa. Some genomic traits like the loss of the atp8 gene or the encoding of all genes on the same strand are homoplastic among the Bivalvia. These characters, gene order, and the nucleotide sequence data show considerable potential of resolving phylogenetic patterns at lower taxonomic levels.
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the complete sequence and gene organization of the mitochondrial genome of the gadilid scaphopod siphonondentalium lobatum Mollusca
Molecular Phylogenetics and Evolution, 2004Co-Authors: Hermann Dreyer, Gerhard SteinerAbstract:Comparisons of mitochondrial gene sequences and gene arrangements can be informative for reconstructing high-level phylogenetic relationships. We determined the complete sequence of the mitochondrial genome of Siphonodentalium lobatum, (Mollusca, Scaphopoda). With only 13,932 bases, it is the shortest Molluscan mitochondrial genome reported so far. The genome contains the usual 13 protein-coding genes, two rRNA and 22 tRNA genes. The ATPase subunit 8 gene is exceptionally short. Several transfer RNAs show truncated TψC arms or DHU arms. The gene arrangement of S. lobatum is markedly different from all other known Molluscan mitochondrial genomes and shows low similarity even to an unpublished gene order of a dentaliid scaphopod. Phylogenetic analyses of all available complete Molluscan mitochondrial genomes based on amino acid sequences of 11 protein-coding genes yield trees with low support for the basal branches. None of the traditionally accepted Molluscan taxa and phylogenies are recovered in all analyses, except for the euthyneuran Gastropoda. S. lobatum appears as the sister taxon to two of the three bivalve species. We conclude that the deep Molluscan phylogeny is probably beyond the resolution of mitochondrial protein sequences. Moreover, assessing the phylogenetic signal in gene order data requires a much larger taxon sample than is currently available, given the exceptional diversity of this character set in the Mollusca.
Gonzalo Giribet - One of the best experts on this subject based on the ideXlab platform.
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Resolving the evolutionary relationships of molluscs with phylogenomic tools
Nature, 2011Co-Authors: Stephen A. Smith, Nerida G. Wilson, Freya E. Goetz, Caitlin Feehery, Sónia C. S. Andrade, Greg W. Rouse, Gonzalo Giribet, Casey W. DunnAbstract:Molluscs (snails, octopuses, clams and their relatives) have a great disparity of body plans and, among the animals, only arthropods surpass them in species number. This diversity has made Mollusca one of the best-studied groups of animals, yet their evolutionary relationships remain poorly resolved. Open questions have important implications for the origin of Mollusca and for morphological evolution within the group. These questions include whether the shell-less, vermiform aplacophoran molluscs diverged before the origin of the shelled molluscs (Conchifera) or lost their shells secondarily. Monoplacophorans were not included in molecular studies until recently, when it was proposed that they constitute a clade named Serialia together with Polyplacophora (chitons), reflecting the serial repetition of body organs in both groups. Attempts to understand the early evolution of molluscs become even more complex when considering the large diversity of Cambrian fossils. These can have multiple dorsal shell plates and sclerites or can be shell-less but with a typical Molluscan radula and serially repeated gills. To better resolve the relationships among molluscs, we generated transcriptome data for 15 species that, in combination with existing data, represent for the first time all major Molluscan groups. We analysed multiple data sets containing up to 216,402 sites and 1,185 gene regions using multiple models and methods. Our results support the clade Aculifera, containing the three Molluscan groups with spicules but without true shells, and they support the monophyly of Conchifera. Monoplacophora is not the sister group to other Conchifera but to Cephalopoda. Strong support is found for a clade that comprises Scaphopoda (tusk shells), Gastropoda and Bivalvia, with most analyses placing Scaphopoda and Gastropoda as sister groups. This well-resolved tree will constitute a framework for further studies of mollusc evolution, development and anatomy.
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assessing the Molluscan hypothesis serialia monoplacophora polyplacophora using novel molecular data
Molecular Phylogenetics and Evolution, 2010Co-Authors: Nerida G. Wilson, Greg W. Rouse, Gonzalo GiribetAbstract:A consensus on Molluscan relationships has yet to be achieved, largely because of conflicting morphological and molecular hypotheses. Monoplacophora show marked seriality of ctenidia, atria, muscles and nephridia and this has been interpreted as plesiomorphic for Mollusca, reflecting a segmented ancestry. More recently this seriality, also partly seen in Polyplacophora, has been seen as a derived condition. Analysis of the first published monoplacophoran DNA sequence from Laevilipilina antarctica Waren & Hain, 1992 [Giribet, G., Okusu, A., Lindgren, A.R., Huff, S., Schrodl, M., Nishiguchi, M.K., 2006. Evidence for a clade composed of molluscs with serially repeated structures: Monoplacophorans are related to chitons. Proc. Natl. Acad. Sci. USA 103, 7723-7728. 10.1073/pnas.0602578103], showed Monoplacophora inside Polyplacophora. These taxa were then grouped under the name Serialia, reflecting the hypothesis that their seriality is a synapomorphy. Subsequent examination revealed that part of the L. antarctica published sequence was the result of contamination with Polyplacophora (Giribet, Supplementary Material S1). We collected and sequenced another monoplacophoran, Laevipilina hyalina McLean, 1979, resulting in the first multi-gene dataset representing all Molluscan classes. Our analyses did not show unambiguous support for Serialia. Model-based approaches strongly supported Serialia as a clade, however, parsimony analyses under dynamic and static homology did not resolve the position of Monoplacophora. Although our study provides support for Serialia and none for Conchifera, it appears that further resolution of Molluscan relationships will require large increases of data.
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evidence for a clade composed of molluscs with serially repeated structures monoplacophorans are related to chitons
Proceedings of the National Academy of Sciences of the United States of America, 2006Co-Authors: Gonzalo Giribet, Akiko Okusu, Annie R Lindgren, Stephanie W Huff, Michael Schrodl, Michele K NishiguchiAbstract:Monoplacophorans are among the rarest members of the phylum Mollusca. Previously only known from fossils since the Cambrian, the first living monoplacophoran was discovered during the famous second Galathea deep-sea expedition. The anatomy of these molluscs shocked the zoological community for presenting serially repeated gills, nephridia, and eight sets of dorsoventral pedal retractor muscles. Seriality of organs in supposedly independent Molluscan lineages, i.e., in chitons and the deep-sea living fossil monoplacophorans, was assumed to be a relict of ancestral Molluscan segmentation and was commonly accepted to support a direct relationship with annelids. We were able to obtain one specimen of a monoplacophoran Antarctic deep-sea species for molecular study. The first molecular data on monoplacophorans, analyzed together with the largest data set of molluscs ever assembled, clearly illustrate that monoplacophorans and chitons form a clade. This “Serialia” concept may revolutionize Molluscan systematics and may have important implications for metazoan evolution as it allows for new interpretations for primitive segmentation in molluscs.
