The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Andrew N. Ostrovsky - One of the best experts on this subject based on the ideXlab platform.
-
first evidence of virus like particles in the bacterial symbionts of Bryozoa
Scientific Reports, 2021Co-Authors: A. E. Vishnyakov, N. P. Karagodina, Andrew N. Ostrovsky, Thomas Schwaha, Andrey V. Letarov, Grace Limfong, P A IvanovAbstract:Bacteriophage communities associated with humans and vertebrate animals have been extensively studied, but the data on phages living in invertebrates remain scarce. In fact, they have never been reported for most animal phyla. Our ultrastructural study showed for the first time a variety of virus-like particles (VLPs) and supposed virus-related structures inside symbiotic bacteria in two marine species from the phylum Bryozoa, the cheilostomes Bugula neritina and Paralicornia sinuosa. We also documented the effect of VLPs on bacterial hosts: we explain different bacterial ‘ultrastructural types’ detected in Bryozoan tissues as stages in the gradual destruction of prokaryotic cells caused by viral multiplication during the lytic cycle. We speculate that viruses destroying bacteria regulate symbiont numbers in the Bryozoan hosts, a phenomenon known in some insects. We develop two hypotheses explaining exo- and endogenous circulation of the viruses during the life-cycle of B. neritina. Finally, we compare unusual ‘sea-urchin’-like structures found in the collapsed bacteria in P. sinuosa with so-called metamorphosis associated contractile structures (MACs) formed in the cells of the marine bacterium Pseudoalteromonas luteoviolacea which are known to trigger larval metamorphosis in a polychaete worm.
-
First ultrastructural evidence of placental nutrition in a ctenostome Bryozoan: example of Amathia verticillata
Zoomorphology, 2019Co-Authors: Thomas Schwaha, Martin Moosbrugger, Manfred Walzl, Andrew N. OstrovskyAbstract:Matrotrophy and its most advanced mode—placentation—is a masterpiece of nature contributing to offspring fitness. It has been studied mainly in vertebrates, whereas so-called placental analogues in invertebrates are poorly known. Here we use an ultrastructural approach to report the first evidence of placentation in the ctenostome Bryozoan Amathia verticillata . This marine colonial suspension-feeder incubates its progeny in the tentacle sheath, which is transformed into a brood chamber. When the fertilized egg is deposited into the brood cavity, the tentacle sheath wall, originally consisting of flattened epithelial cells, is modified into an embryophore (placental analogue) via cell multiplication and hypertrophy. The embryophore (nutritive) cells develop a massive secretory apparatus and acquire ‘microvillous’ apical membranes indicating the presence of exocytosis. In turn, the embryo surface cells also form a complex network of irregular projections and foldings. Coated pits beneath this network indicate active endocytosis. The developing embryo is adjacent to the embryophore and the narrow slit between them is filled with dense and flocculent (presumably nutritive) material. The embryo increases up to 24-fold in size indicating substantial matrotrophic provisioning. We compare the ultrastructural details of placentation in A. verticillata with those known in cheilostome Bryozoans, and review the major structural principles of placentation in Bryozoa in general. We then discuss possible ways of nutrient transport to the embryophore in various Bryozoan clades.
-
Ultrastructural evidence for nutritional relationships between a marine colonial invertebrate (Bryozoa) and its bacterial symbionts
Symbiosis, 2017Co-Authors: N. P. Karagodina, A. E. Vishnyakov, Olga N. Kotenko, Arina L Maltseva, Andrew N. OstrovskyAbstract:Autozooids of the cheilostome Bryozoan Aquiloniella scabra contain rod-like bacteria in the funicular bodies – the complex swellings of the funicular strands. Each funicular body contains symbionts in the central cavity surrounded by a large, synthetically active internal “sheath-cell” (bacteriocyte) and a group of the flat external cells. The tightly interdigitating lobes of these cells form a capsule well-isolated from the body cavity. Slit-like spaces between bacteria are filled with electron-dense matrix and cytoplasmic processes of various sizes and shapes (often branching) produced by the “sheath-cell”. The cell ultrastructure and complex construction of the funicular bodies as well as multiplication of the bacteria in them suggest metabolic exchange between host and symbiont, involving the nourishment of bacteria. We suggest that the bacteria, in turn, influence the Bryozoan mesothelial tissue to form the funicular bodies as capsules for bacterial incubation. We present ultrastructural data, discuss possible variants in the development of the funicular bodies in Bryozoa, and propose the possible role of bacteria in the life of their Bryozoan host.
-
novel brominated metabolites from Bryozoa a functional analysis
Natural Product Research, 2017Co-Authors: Arina L Maltseva, Olga N. Kotenko, Vladimir A Kutyumov, Darya A Matvienko, Alexey L Shavarda, Michael K Winson, Andrew N. OstrovskyAbstract:AbstractMarine invertebrates are a promising source of novel natural products with biological activities. The phylum Bryozoa is relatively under-investigated in this context, although a number of compounds with medical potential has been discovered in recent years. Here, we report on the novel group of brominated metabolites from the Bryozoan Terminoflustra membranaceatruncata, including analysis of biological activities of the tribrominated terminoflustrindole A (Cm-1) and the structures of the related dibrominated variants terminoflustrindoles B and C. Terminoflustrindole A was previously shown to have fungicidal properties. Although they vary by just one bromine group in each case from terminoflustrindole A, in this study, we report that terminoflustrindoles B and C exhibit no antimicrobial activity in the same assays. In addition to displaying antifungal activity, Terminoflustrindole A was also found to exhibit potent cytotoxic activity when tested against tumour cell lines. The gradient distribution ...
-
from incipient to substantial evolution of placentotrophy in a phylum of aquatic colonial invertebrates
Evolution, 2013Co-Authors: Andrew N. OstrovskyAbstract:Matrotrophy has long been known in invertebrates, but it is still poorly understood and has never been reviewed. A striking example of matrotrophy (namely, placentotrophy) is provided by the Bryozoa, a medium-sized phylum of the aquatic colonial filter feeders. Here I report on an extensive anatomical study of placental analogues in 21 species of the Bryozoan order Cheilostomata, offering the first review on matrotrophy among aquatic invertebrates. The first anatomical description of incipient placentotrophy in invertebrates is presented together with the evidence for multiple independent origins of placental analogues in this order. The combinations of contrasting oocytic types (macrolecithal or microlecithal) and various degrees of placental development and embryonic enlargement during incubation, found in different Bryozoan species, are suggestive of a transitional series from the incipient to the substantial placentotrophy accompanied by an inverse change in oogenesis, a situation reminiscent of some vertebrates. It seems that matrotrophy could trigger the evolution of sexual zooidal polymorphism in some clades. The results of this study show that this phylum, with its wide variety of reproductive patterns, incubation devices, and types of the simple placenta-like systems, offers a promising model for studying parallel evolution of placentotrophy in particular, and matrotrophy in general.
Andreas Hejnol - One of the best experts on this subject based on the ideXlab platform.
-
gene expression in Bryozoan larvae suggest a fundamental importance of pre patterned blastemic cells in the Bryozoan life cycle
Evodevo, 2011Co-Authors: Judith Fuchs, Mark Q Martindale, Andreas HejnolAbstract:Bryozoa is a clade of aquatic protostomes. The Bryozoan life cycle typically comprises a larval stage, which metamorphoses into a sessile adult that proliferates by asexual budding to form colonies. The homology of Bryozoan larvae with other protostome larvae is enigmatic. Bryozoan larvae exhibit blastemic tissues that contribute to build the adult during morphogenesis. However, it remains unclear if the cells of these tissues are pre-determined according to their future fate or if the cells are undifferentiated, pluripotent stem cells. Gene expression studies can help to identify molecular patterning of larval and adult tissues and enlighten the evolution of Bryozoan life cycle stages. We investigated the spatial expression of 13 developmental genes in the larval stage of the gymnolaemate Bryozoan Bugula neritina. We found most genes expressed in discrete regions in larval blastemic tissues that form definitive components of the adult body plan. Only two of the 13 genes, BnTropomyosin and BnFoxAB, were exclusively expressed in larval tissues that are discarded during metamorphosis. Our results suggest that the larval blastemas in Bugula are pre-patterned according to their future fate in the adult. The gene expression patterns indicate that some of the Bryozoan blastemas can be interpreted to correspond to homologous adult tissues of other animals. This study challenges an earlier proposed view that metazoan larvae share homologous undifferentiated "set-aside cells", and instead points to an independent origin of the Bryozoan larval stage with respect to other lophotrochozoans.
-
Gene expression in Bryozoan larvae suggest a fundamental importance of pre-patterned blastemic cells in the Bryozoan life-cycle
EvoDevo, 2011Co-Authors: Judith Fuchs, Mark Q Martindale, Andreas HejnolAbstract:Background Bryozoa is a clade of aquatic protostomes. The Bryozoan life cycle typically comprises a larval stage, which metamorphoses into a sessile adult that proliferates by asexual budding to form colonies. The homology of Bryozoan larvae with other protostome larvae is enigmatic. Bryozoan larvae exhibit blastemic tissues that contribute to build the adult during morphogenesis. However, it remains unclear if the cells of these tissues are pre-determined according to their future fate or if the cells are undifferentiated, pluripotent stem cells. Gene expression studies can help to identify molecular patterning of larval and adult tissues and enlighten the evolution of Bryozoan life cycle stages. Results We investigated the spatial expression of 13 developmental genes in the larval stage of the gymnolaemate Bryozoan Bugula neritina . We found most genes expressed in discrete regions in larval blastemic tissues that form definitive components of the adult body plan. Only two of the 13 genes, BnTropomyosin and BnFoxAB , were exclusively expressed in larval tissues that are discarded during metamorphosis. Conclusions Our results suggest that the larval blastemas in Bugula are pre-patterned according to their future fate in the adult. The gene expression patterns indicate that some of the Bryozoan blastemas can be interpreted to correspond to homologous adult tissues of other animals. This study challenges an earlier proposed view that metazoan larvae share homologous undifferentiated "set-aside cells", and instead points to an independent origin of the Bryozoan larval stage with respect to other lophotrochozoans.
Thomas Schwaha - One of the best experts on this subject based on the ideXlab platform.
-
first evidence of virus like particles in the bacterial symbionts of Bryozoa
Scientific Reports, 2021Co-Authors: A. E. Vishnyakov, N. P. Karagodina, Andrew N. Ostrovsky, Thomas Schwaha, Andrey V. Letarov, Grace Limfong, P A IvanovAbstract:Bacteriophage communities associated with humans and vertebrate animals have been extensively studied, but the data on phages living in invertebrates remain scarce. In fact, they have never been reported for most animal phyla. Our ultrastructural study showed for the first time a variety of virus-like particles (VLPs) and supposed virus-related structures inside symbiotic bacteria in two marine species from the phylum Bryozoa, the cheilostomes Bugula neritina and Paralicornia sinuosa. We also documented the effect of VLPs on bacterial hosts: we explain different bacterial ‘ultrastructural types’ detected in Bryozoan tissues as stages in the gradual destruction of prokaryotic cells caused by viral multiplication during the lytic cycle. We speculate that viruses destroying bacteria regulate symbiont numbers in the Bryozoan hosts, a phenomenon known in some insects. We develop two hypotheses explaining exo- and endogenous circulation of the viruses during the life-cycle of B. neritina. Finally, we compare unusual ‘sea-urchin’-like structures found in the collapsed bacteria in P. sinuosa with so-called metamorphosis associated contractile structures (MACs) formed in the cells of the marine bacterium Pseudoalteromonas luteoviolacea which are known to trigger larval metamorphosis in a polychaete worm.
-
First evidence of virus-like particles in the bacterial symbionts of Bryozoa
2020Co-Authors: A. E. Vishnyakov, N. P. Karagodina, Thomas Schwaha, Grace E. Lim-fong, Pavel Ivanov, Andrey V. Letarov, A. N. OctrovskyAbstract:ABSTRACT Bacteriophage communities associated with humans and vertebrate animals have been extensively studied, but the data on phages living in invertebrates remain scarce. In fact, they have never been reported for most animal phyla. Our ultrastructural study showed for the first time a variety of virus-like particles (VLPs) and supposed virus-related structures inside symbiotic bacteria in two marine species from the phylum Bryozoa, the cheilostomes Bugula neritina and Paralicornia sinuosa. We also documented the effect of VLPs on bacterial hosts: we explain different bacterial ‘ultrastructural types’ detected in Bryozoan tissues as stages in the gradual destruction of prokaryotic cells caused by viral multiplication during the lytic cycle. We speculate that viruses destroying bacteria regulate symbiont numbers in the Bryozoan hosts, a phenomenon known in some insects. We develop two hypotheses explaining exo- and endogenous circulation of the viruses during the life-cycle of B. neritina. Finally, we compare unusual ‘sea-urchin’-like structures found in the collapsed bacteria in P. sinuosa with so-called metamorphosis associated complexes (MACs) known to trigger larval metamorphosis in a polychaete worm. Importance Complex symbiotic systems, including metazoan hosts, their bacterial symbionts and bacteriophages are widely studied using vertebrate models whereas much less is known about invertebrates. Our ultrastructural research revealed replication of the viruses and/or activation of virus related elements in the bacterial symbionts inhabiting tissues of the marine colonial invertebrates (phylum Bryozoa). The virus activity in the bacterial cells that are believed to be transmitted exclusively vertically is of a special importance. In addition, in the bacterial symbionts of one of the Bryozoan hosts we observed the massive replication of the structures seemingly related to the Metamorphosis associated complexes (MAC). To our knowledge, MACs were never reported in the animal prokaryotic symbionts. Our findings indicate that Bryozoa may be new suitable model to study the role of bacteriophages and phage-related structures in the complex symbiotic systems hosted by marine invertebrates.
-
First ultrastructural evidence of placental nutrition in a ctenostome Bryozoan: example of Amathia verticillata
Zoomorphology, 2019Co-Authors: Thomas Schwaha, Martin Moosbrugger, Manfred Walzl, Andrew N. OstrovskyAbstract:Matrotrophy and its most advanced mode—placentation—is a masterpiece of nature contributing to offspring fitness. It has been studied mainly in vertebrates, whereas so-called placental analogues in invertebrates are poorly known. Here we use an ultrastructural approach to report the first evidence of placentation in the ctenostome Bryozoan Amathia verticillata . This marine colonial suspension-feeder incubates its progeny in the tentacle sheath, which is transformed into a brood chamber. When the fertilized egg is deposited into the brood cavity, the tentacle sheath wall, originally consisting of flattened epithelial cells, is modified into an embryophore (placental analogue) via cell multiplication and hypertrophy. The embryophore (nutritive) cells develop a massive secretory apparatus and acquire ‘microvillous’ apical membranes indicating the presence of exocytosis. In turn, the embryo surface cells also form a complex network of irregular projections and foldings. Coated pits beneath this network indicate active endocytosis. The developing embryo is adjacent to the embryophore and the narrow slit between them is filled with dense and flocculent (presumably nutritive) material. The embryo increases up to 24-fold in size indicating substantial matrotrophic provisioning. We compare the ultrastructural details of placentation in A. verticillata with those known in cheilostome Bryozoans, and review the major structural principles of placentation in Bryozoa in general. We then discuss possible ways of nutrient transport to the embryophore in various Bryozoan clades.
-
Reconstructing the muscular ground pattern of phylactolaemate Bryozoans: first data from gelatinous representatives
BMC Evolutionary Biology, 2017Co-Authors: Natalie Gawin, Andreas Wanninger, Thomas SchwahaAbstract:Phylactolaemata is commonly regarded the earliest branch within Bryozoa and thus the sister group to the other Bryozoan taxa, Cyclostomata and Gymnolaemata. Therefore, the taxon is important for the reconstruction of the Bryozoan morphological ground pattern. In this study the myoanatomy of Pectinatella magnifica, Cristatella mucedo and Hyalinella punctata was analysed by means of histology, f-actin staining and confocal laser-scanning microscopy in order to fill gaps in knowledge concerning the myoanatomy of Phylactolaemata. The retractor muscles and muscles of the aperture, gut, body wall, tentacle sheath, lophophore constitute the most prominent muscular subsets in these species. The lophophore shows longitudinal muscle bands in the tentacles, lophophoral arm muscles, epistome musculature and hitherto undescribed muscles of the ring canal. In general the muscular system of the three species is very similar with differences mainly in the body wall, tentacle sheath and epistome. The body wall contains an orthogonal grid of musculature. The epistome exhibits either a muscular meshwork in the epistomal wall or muscle fibers traversing the epistomal cavity. The whole tentacle sheath possesses a regular mesh of muscles in Pectinatella and Cristatella, whereas circular muscles are limited to the tentacle sheath base in Hyalinella. This study is the first to describe muscles of the ring canal and contributes to reconstructing muscular features for the last common ancestor of all Bryozoans. The data available suggest that two longitudinal muscle bands in the tentacles, as well as retractor muscles and longitudinal and circular muscles in the tentacle sheath, were present in the last common Bryozoan ancestor. Comparisons among Bryozoans shows that several apomorphies are present in the myoanatomy of each class- level taxon such as the epistomal musculature and musculature of the lophophoral arms in phylactolaemates, annular muscles in cyclostomes and parietal muscles in gymnolaemates.
-
Reconstructing the muscular ground pattern of phylactolaemate Bryozoans: first data from gelatinous representatives
BMC, 2017Co-Authors: Natalie Gawin, Andreas Wanninger, Thomas SchwahaAbstract:Abstract Background Phylactolaemata is commonly regarded the earliest branch within Bryozoa and thus the sister group to the other Bryozoan taxa, Cyclostomata and Gymnolaemata. Therefore, the taxon is important for the reconstruction of the Bryozoan morphological ground pattern. In this study the myoanatomy of Pectinatella magnifica, Cristatella mucedo and Hyalinella punctata was analysed by means of histology, f-actin staining and confocal laser-scanning microscopy in order to fill gaps in knowledge concerning the myoanatomy of Phylactolaemata. Results The retractor muscles and muscles of the aperture, gut, body wall, tentacle sheath, lophophore constitute the most prominent muscular subsets in these species. The lophophore shows longitudinal muscle bands in the tentacles, lophophoral arm muscles, epistome musculature and hitherto undescribed muscles of the ring canal. In general the muscular system of the three species is very similar with differences mainly in the body wall, tentacle sheath and epistome. The body wall contains an orthogonal grid of musculature. The epistome exhibits either a muscular meshwork in the epistomal wall or muscle fibers traversing the epistomal cavity. The whole tentacle sheath possesses a regular mesh of muscles in Pectinatella and Cristatella, whereas circular muscles are limited to the tentacle sheath base in Hyalinella. Conclusion This study is the first to describe muscles of the ring canal and contributes to reconstructing muscular features for the last common ancestor of all Bryozoans. The data available suggest that two longitudinal muscle bands in the tentacles, as well as retractor muscles and longitudinal and circular muscles in the tentacle sheath, were present in the last common Bryozoan ancestor. Comparisons among Bryozoans shows that several apomorphies are present in the myoanatomy of each class- level taxon such as the epistomal musculature and musculature of the lophophoral arms in phylactolaemates, annular muscles in cyclostomes and parietal muscles in gymnolaemates
Andrej Ernst - One of the best experts on this subject based on the ideXlab platform.
-
the last phylum occupation of Bryozoa morpho ecospace colony growth habits during the early phase of the great ordovician biodiversification event
Palaeogeography Palaeoclimatology Palaeoecology, 2019Co-Authors: Steven J Hageman, Andrej ErnstAbstract:Abstract Most major phyla, and all skeletonized phyla have their first appearance in the Cambrian. The exception is the Phylum Bryozoa, which first appear in the Early Ordovician (Tremadocian 1b). Bryozoans have an excellent fossil record, due in part to their benthic marine habitat with skeletal colonies composed largely of stable, low-Magnesium calcite. These factors provide an unrivaled opportunity to observe patterns and rates of radiation of a new phylum into disparate morpho- ecospace through the Great Ordovician Biodiversification Event (GOBE). In this study, the colonial growth habits of all known skeletonized Bryozoa (181 species) from the Early and Middle Ordovician are characterized in a new classification scheme based on processes of growth, rather than their end geometry as most traditional classifications of Bryozoan growth habits. These fundamental categories are: orientation, dimensions of primary growth, width of colony unit, layers of zooecia, substrate relationships, space utilization, skeleton mineralization, plus sub-categories of orientation based on their geometry. In the Early and Middle Ordovician there are 85 unique growth habits defined by these eight growth habit characters. By the end of Middle Ordovician, about 4.8% of the morpho-ecospace defined by two subsets of the characters had been occupied by five Bryozoan orders (represented by 34 families, 77 genera). When plotted by Ordovician stage time-slices (ca. 2.2 my each), a sharp increase in taxonomic and growth habit occurrence is observed at the Early-Middle Ordovician transition, earlier than in other groups. Individual growth habit character states also show significant changes at this transition. In the Early Ordovician, low Bryozoan taxonomic and growth habit richness is due in part to sampling bias and modified search methods are need, however, the overall patterns (Early-Mid. Ordovician transition) observed in this study are robust and not expected to change fundamentally with additional data.
-
Diversity dynamics and evolutionary patterns of Devonian Bryozoa
Palaeobiodiversity and Palaeoenvironments, 2013Co-Authors: Andrej ErnstAbstract:Bryozoan diversity during the Devonian period displays a persistent rise from the Pragian to the early Givetian, significantly dropping in the late Givetian in the wake of the Taghanic Event. In contrast, two other important events during the Devonian, the Frasne/Famenne Event and the Hangenberg Event at the Devonian/Carboniferous boundary, were less significant and resulted mainly in shifts in faunal composition. Diversity dynamics of Devonian Bryozoa was apparently controlled by extrinsic and intrinsic factors. Global palaeogeographic settings influenced faunal provincialism to which Bryozoans seem to be sensitive. Sea-level fluctuations and subsequent changes in suitability of habitats influenced biodiversification processes in Bryozoans. Intrinsically, Bryozoans show some patterns consistent with diffuse co-evolution with potential predators and, possibly, prey. Observed trends in the morphological evolution of Devonian Bryozoans include some obvious anti-predator adaptations (protective structures, strengthened skeletal walls). Moreover, Devonian Bryozoans often developed various internal modifications, which apparently influenced the activity of polypides. This pattern is regarded here as apparent improvement of feeding, possibly as a response to diminishing food in the course of the mid-Palaeozoic Phytoplankton Blackout.
-
Homeomorphy in Lunostoma, a new Middle Devonian cryptostome Bryozoan
Paläontologische Zeitschrift, 2012Co-Authors: Andrej Ernst, Paul D. Taylor, Jan Bohatý, Patrick N. Wyse JacksonAbstract:A new genus and species of rhabdomesine cryptostome Bryozoan, Lunostoma pulchra n. gen. n. sp., is described from the Lower Givetian (Middle Devonian) of the Eifel, Germany. It differs from all previously known rhabdomesines in having crescent-shaped structures (“scuta”) on the proximal sides of the apertures. These scuta resemble the lunaria that characterise cystoporate Bryozoans, providing yet another example of homeomorphy in the Bryozoa. The function of scuta is unclear as, in contrast to lunaria, they do not project sufficiently from the apertures to constrain the everting lophophores. Eine neue Gattung und Art einer rhabdomesinen cryptostomen Bryozoe wird als Lunostoma pulchra n. gen. n. sp. aus dem unteren Givetium (Mittel-Devon) der Eifel (Rheinisches Schiefergebirge, Deutschland) beschrieben. Morphologisch unterscheidet sie sich von allen bekannten Rhabdomesina durch halbmondförmige Strukturen („Scuta”) an den proximalen Seiten der Aperturen. Diese Scuta ähneln frappant den für cystoporate Bryozoen charakteristischen Lunarien und liefern damit Beispiel für Homeomorphie bei paläozoischen Bryozoen. Die Funktion der Scuta ist nicht klar, anders als bei Lunaria, da sie nicht weit genug aus den Aperturen hinausragen um die Ausstülpung der Lophophoren einzuschränken.
-
Stenolaemate Bryozoans from the Geirud Formation (Upper Devonian/Lower Carboniferous) of Central Alborz (Iran)
Paläontologische Zeitschrift, 2009Co-Authors: Andrej Ernst, Mahin MohammadiAbstract:Erstmals werden zwei Bryozoenarten der Geirud Formation (Oberdevon/Unterkarbon) des zentralen Elburs-Gebirges (Iran) beschrieben. Zwei Bryozoenarten werden aus der Geirud Formation (Upper Devonian/Early Carboniferous) von Zentral Alborz (Iran) beschrieben. Die trepostome Bryozoe Schulgina mutabilis Troizkaya, 1975 wurde zuvor aus dem Oberdevon (Famenne) von Zentralkasachstan bekannt. Die neue Art Ascopora geirudensis n. sp. ist der früheste bekannte Vertreter der rhabdomesinen Gattung Ascopora Trautschold, 1876. Two Bryozoan species are described from the Geirud Formation (Upper Devonian/Lower Carboniferous) of Central Alborz (Iran). Trepostome Schulgina mutabilis Troizkaya, 1975 is known from the Upper Devonian (Famennian) of Central Kazakhstan. The new species Ascopora geirudensis n. sp. is the earliest known representative of the rhabdomesine genus Ascopora Trautschold, 1876.
Judith Fuchs - One of the best experts on this subject based on the ideXlab platform.
-
Gene expression in Bryozoan larvae suggest a fundamental importance of pre-patterned blastemic cells in the Bryozoan life-cycle
EvoDevo, 2011Co-Authors: Judith Fuchs, Mark Q Martindale, Andreas HejnolAbstract:Background Bryozoa is a clade of aquatic protostomes. The Bryozoan life cycle typically comprises a larval stage, which metamorphoses into a sessile adult that proliferates by asexual budding to form colonies. The homology of Bryozoan larvae with other protostome larvae is enigmatic. Bryozoan larvae exhibit blastemic tissues that contribute to build the adult during morphogenesis. However, it remains unclear if the cells of these tissues are pre-determined according to their future fate or if the cells are undifferentiated, pluripotent stem cells. Gene expression studies can help to identify molecular patterning of larval and adult tissues and enlighten the evolution of Bryozoan life cycle stages. Results We investigated the spatial expression of 13 developmental genes in the larval stage of the gymnolaemate Bryozoan Bugula neritina . We found most genes expressed in discrete regions in larval blastemic tissues that form definitive components of the adult body plan. Only two of the 13 genes, BnTropomyosin and BnFoxAB , were exclusively expressed in larval tissues that are discarded during metamorphosis. Conclusions Our results suggest that the larval blastemas in Bugula are pre-patterned according to their future fate in the adult. The gene expression patterns indicate that some of the Bryozoan blastemas can be interpreted to correspond to homologous adult tissues of other animals. This study challenges an earlier proposed view that metazoan larvae share homologous undifferentiated "set-aside cells", and instead points to an independent origin of the Bryozoan larval stage with respect to other lophotrochozoans.
-
gene expression in Bryozoan larvae suggest a fundamental importance of pre patterned blastemic cells in the Bryozoan life cycle
Evodevo, 2011Co-Authors: Judith Fuchs, Mark Q Martindale, Andreas HejnolAbstract:Bryozoa is a clade of aquatic protostomes. The Bryozoan life cycle typically comprises a larval stage, which metamorphoses into a sessile adult that proliferates by asexual budding to form colonies. The homology of Bryozoan larvae with other protostome larvae is enigmatic. Bryozoan larvae exhibit blastemic tissues that contribute to build the adult during morphogenesis. However, it remains unclear if the cells of these tissues are pre-determined according to their future fate or if the cells are undifferentiated, pluripotent stem cells. Gene expression studies can help to identify molecular patterning of larval and adult tissues and enlighten the evolution of Bryozoan life cycle stages. We investigated the spatial expression of 13 developmental genes in the larval stage of the gymnolaemate Bryozoan Bugula neritina. We found most genes expressed in discrete regions in larval blastemic tissues that form definitive components of the adult body plan. Only two of the 13 genes, BnTropomyosin and BnFoxAB, were exclusively expressed in larval tissues that are discarded during metamorphosis. Our results suggest that the larval blastemas in Bugula are pre-patterned according to their future fate in the adult. The gene expression patterns indicate that some of the Bryozoan blastemas can be interpreted to correspond to homologous adult tissues of other animals. This study challenges an earlier proposed view that metazoan larvae share homologous undifferentiated "set-aside cells", and instead points to an independent origin of the Bryozoan larval stage with respect to other lophotrochozoans.
-
The first comprehensive molecular phylogeny of Bryozoa (Ectoprocta) based on combined analyses of nuclear and mitochondrial genes.
Molecular Phylogenetics and Evolution, 2009Co-Authors: Judith Fuchs, Matthias Obst, Per SundbergAbstract:Bryozoa is one of the most puzzling phyla in the animal kingdom and little is known about their evolutionary history. Its phylogenetic position among the Metazoa remains unsettled, as well as its intra-phylum relationships. Here, we present the first comprehensive molecular phylogeny of Bryozoa based on the mitochondrial gene COI and two nuclear genes 18S rDNA and 28S rDNA including 32 species from 23 families. We show that the monophyletic status is supported for the phylum as well as for previously defined Bryozoan classes. The 28S rDNA supports a close relationship of Phylactolaemata and Stenolaemata, while partial COI and 18S rDNA show the freshwater Phylactolaemata as basal Bryozoans. The Gymnolaemata have generally been divided into soft-bodied forms (Ctenostomata) and hard-bodied species (Cheilostomata). In our analyses all three genes conflict with this assumption and show hard body forms having evolved within Gymnolaemata several times.
