Academic literature on the topic 'Ascidies – Reproduction (biologie)'
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Journal articles on the topic "Ascidies – Reproduction (biologie)"
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Sordino, Paolo, Lisa Belluzzi, Rosaria De Santis, and William C. Smith. "Developmental genetics in primitive chordates." Philosophical Transactions of the Royal Society of London. Series B: Biological Sciences 356, no. 1414 (October 29, 2001): 1573–82. http://dx.doi.org/10.1098/rstb.2001.0919.
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Recent advances in the study of the genetics and genomics of urochordates testify to a renewed interest in this chordate subphylum, believed to be the most primitive extant chordate relatives of the vertebrates. In addition to their primitive nature, many features of their reproduction and early development make the urochordates ideal model chordates for developmental genetics. Many urochordates spawn large numbers of transparent and externally developing embryos on a daily basis. Additionally, the embryos have a defined and well–characterized cell lineage until the end of gastrulation. Furthermore, the genomes of the urochordates have been estimated to be only 5–10% of the size of the vertebrates and to have fewer genes and less genetic redundancy than vertebrates. Genetic screens, which are powerful tools for investigating developmental mechanisms, have recently become feasible due to new culturing techniques in ascidians. Because hermaphrodite ascidians are able to self–fertilize, recessive mutations can be detected in a single generation. Several recent studies have demonstrated the feasibility of applying modern genetic techniques to the study of ascidian biology.
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Gallo, Alessandra, Maria Consiglia Esposito, Elisabetta Tosti, and Raffaele Boni. "Sperm Motility, Oxidative Status, and Mitochondrial Activity: Exploring Correlation in Different Species." Antioxidants 10, no. 7 (July 16, 2021): 1131. http://dx.doi.org/10.3390/antiox10071131.
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Sperm quality assessment is the first step for evaluating male fertility and includes the estimation of sperm concentration, motility, and morphology. Nevertheless, other parameters can be assessed providing additional information on the male reproductive potential. This study aimed to evaluate and correlate the oxidative status, mitochondrial functionality, and motility in spermatozoa of two marine invertebrate (Ciona robusta and Mytilus galloprovincialis) and one mammalian (Bos taurus) species. By combining fluorescent staining and spectrofluorometer, sperm oxidative status was evaluated through intracellular reactive oxygen species (ROS) and plasma membrane lipid peroxidation (LPO) analysis. Mitochondrial functionality was assessed through the mitochondrial membrane potential (MMP). In the three examined species, a negative correlation emerged between sperm motility vs ROS levels and LPO. Sperm motility positively correlated with MMP in bovine, whereas these parameters were not related in ascidian or even negatively related in mussel spermatozoa. MMP was negatively related to ROS and LPO levels in ascidians, only to LPO in bovine, and positively related in mussel spermatozoa. These results suggest that energy sources for sperm motility vary between species and that ROS causes a decline in sperm motility via oxidative damage of membrane lipids. Overall, this study validates the use of fluorescent probes in combination with spectrofluorometer as a simple and powerful methodology for supplementary evaluation of sperm quality shedding light on new potential quality markers and provided relevant information on sperm energetic metabolism.
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Ohta, Naoyuki, Nicole Kaplan, James Tyler Ng, Basile Jules Gravez, and Lionel Christiaen. "Asymmetric Fitness of Second-Generation Interspecific Hybrids Between Ciona robusta and Ciona intestinalis." G3: Genes|Genomes|Genetics 10, no. 8 (June 9, 2020): 2697–711. http://dx.doi.org/10.1534/g3.120.401427.
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Reproductive isolation is central to speciation, but interspecific crosses between two closely related species can produce viable and fertile hybrids. Two different species of tunicates in the same ascidian genus, Ciona robusta and Ciona intestinalis, can produce hybrids. However, wild sympatric populations display limited gene flow, suggesting the existence of obstacles to interspecific reproduction that remain unknown. Here, we took advantage of a closed culture system to cross C. robusta with C. intestinalis and established F1 and F2 hybrids. We monitored post-embryonic development, survival, and sexual maturation to characterize the genetic basis of simple traits, and further probe the physiological mechanisms underlying reproductive isolation. Partial viability of first and second generation hybrids suggested that both pre- and postzygotic mechanisms contributed to genomic incompatibilities in hybrids. We observed asymmetric fitness, whereby the C. intestinalis maternal lines fared more poorly in our system, pointing to maternal origins of species-specific sensitivity. We discuss the possibility that asymmetrical second generation inviability and infertility emerge from interspecific incompatibilities between the nuclear and mitochondrial genomes, or other maternal effect genes. This work paves the way to quantitative genetic approaches to study the mechanisms underlying genomic incompatibilities and other complex traits in the genome-enabled Ciona model.
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Sutovsky, Peter. "Sperm proteasome and fertilization." REPRODUCTION 142, no. 1 (July 2011): 1–14. http://dx.doi.org/10.1530/rep-11-0041.
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The omnipresent ubiquitin–proteasome system (UPS) is an ATP-dependent enzymatic machinery that targets substrate proteins for degradation by the 26S proteasome by tagging them with an isopeptide chain composed of covalently linked molecules of ubiquitin, a small chaperone protein. The current knowledge of UPS involvement in the process of sperm penetration through vitelline coat (VC) during human and animal fertilization is reviewed in this study, with attention also being given to sperm capacitation and acrosome reaction/exocytosis. In ascidians, spermatozoa release ubiquitin-activating and conjugating enzymes, proteasomes, and unconjugated ubiquitin to first ubiquitinate and then degrade the sperm receptor on the VC; in echinoderms and mammals, the VC (zona pellucida/ZP in mammals) is ubiquitinated during oogenesis and the sperm receptor degraded during fertilization. Various proteasomal subunits and associated enzymes have been detected in spermatozoa and localized to sperm acrosome and other sperm structures. By using specific fluorometric substrates, proteasome-specific proteolytic and deubiquitinating activities can be measured in live, intact spermatozoa and in sperm protein extracts. The requirement of proteasomal proteolysis during fertilization has been documented by the application of various proteasome-specific inhibitors and antibodies. A similar effect was achieved by depletion of sperm-surface ATP. Degradation of VC/ZP-associated sperm receptor proteins by sperm-borne proteasomes has been demonstrated in ascidians and sea urchins. On the applied side, polyspermy has been ameliorated by modulating sperm-associated deubiquitinating enzymes. Diagnostic and therapeutic applications could emerge in human reproductive medicine. Altogether, the studies on sperm proteasome indicate that animal fertilization is controlled in part by a unique, gamete associated, extracellular UPS.
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Kinoshita-Terauchi, Nana, Kogiku Shiba, Makoto Terauchi, Francisco Romero, Héctor Vincente Ramírez-Gómez, Manabu Yoshida, Taizo Motomura, Hiroshi Kawai, and Takuya Nishigaki. "High potassium seawater inhibits ascidian sperm chemotaxis, but does not affect the male gamete chemotaxis of a brown alga." Zygote 27, no. 4 (July 18, 2019): 225–31. http://dx.doi.org/10.1017/s0967199419000224.
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SummaryMale gamete chemotaxis towards the female gamete is a general strategy to facilitate the sexual reproduction in many marine eukaryotes. Biochemical studies of chemoattractants for male gametes of brown algae have advanced in the 1970s and 1980s, but the molecular mechanism of male gamete responses to the attractants remains elusive. In sea urchin, a K+ channel called the tetraKCNG channel plays a fundamental role in sperm chemotaxis and inhibition of K+ efflux through this channel by high K+ seawater blocks almost all cell responses to the chemoattractant. This signalling mechanism could be conserved in marine invertebrates as tetraKCNG channels are conserved in the marine invertebrates that exhibit sperm chemotaxis. We confirmed that high K+ seawater also inhibited sperm chemotaxis in ascidian, Ciona intestinalis (robusta), in this study. Conversely, the male gamete chemotaxis towards the female gamete of a brown alga, Mutimo cylindricus, was preserved even in high K+ seawater. This result indicates that none of the K+ channels is essential for male gamete chemotaxis in the brown alga, suggesting that the signalling mechanism for chemotaxis in this brown alga is quite different from that of marine invertebrates. Correlated to this result, we revealed that the channels previously proposed as homologues of tetraKCNG in brown algae have a distinct domain composition from that of the tetraKCNG. Namely, one of them possesses two repeats of the six transmembrane segments (diKCNG) instead of four. The structural analysis suggests that diKCNG is a cyclic nucleotide-modulated and/or voltage-gated K+ channel.
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El-Mouatassim, Said, Stefania Bilotto, Gian Luigi Russo, Elisabetta Tosti, and Yves Menezo. "APEX/Ref-1 (apurinic/apyrimidic endonuclease DNA-repair gene) expression in human and ascidian (Ciona intestinalis) gametes and embryos *." MHR: Basic science of reproductive medicine 13, no. 8 (June 13, 2007): 549–56. http://dx.doi.org/10.1093/molehr/gam038.
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Lindquist, Evert E., and King Wan Wu. "REVIEW OF MITES OF THE GENUS MUCROSEIUS (ACARI: MESOSTIGMATA: ASCIDAE) ASSOCIATED WITH SAWYER BEETLES (CERAMBYCIDAE: MONOCHAMUS AND MECYNIPPUS) AND PINE WOOD NEMATODES [APHELENCHOIDIDAE: BURSAPHELENCHUS XYLOPHILUS (STEINER AND BUHRER) NICKLE], WITH DESCRIPTIONS OF SIX NEW SPECIES FROM JAPAN AND NORTH AMERICA, AND NOTES ON THEIR PREVIOUS MISIDENTIFICATION." Canadian Entomologist 123, no. 4 (August 1991): 875–927. http://dx.doi.org/10.4039/ent123875-4.
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AbstractSix new species of Mucroseius having adult females phoretic on adult sawyer beetles of the genus Monochamus are described: Mucroseius nipponensis and Mucroseius squamosus from Monochamus alternatus Hope in Japan, Mucroseius algonquian from three species of Monochamus in eastern Canada and eastern United States, Mucroseius disparisetus from Monochamus titillator (Fabricius) in southeastern United States, Mucroseius Californicus from Monochamus clamator (LeConte) in California, and Mucroseius mexicanus from Monochamus rubigineus (Bates) in Mexico. Mucroseius aciculatus (Ishikawa, 1968), new combination, from Mecynippus pubicornis Bates in Japan, and the type-species, Mucroseius monochami Lindquist, 1962, from several species of Monochamus widely distributed in North America, are redescribed. Misidentifications of these species in the Japanese and North American literature are noted, and a key is given for these eight species. One adult female of an undescribed species found on a sawyer, Monochamus sutor Linnaeus, from Europe, is noted as possibly belonging to Mucroseius.The taxon Mucroseius is redescribed, and its problematic status as a genus is reviewed. The phylogenetic position of Mucroseius, which appears to be derived within the genus Proctolaelaps, is discussed. Previous observations on biological and ecological aspects of Mucroseius mites, including those published in Japanese, are critically reviewed, with new data added for host ranges and specificities, distribution, phoretic behavior, occurrence in sawyer gallery systems, mode of reproduction, and their association with the pine wood nematode, Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle. Cheliceral structure and speculations on the feeding habits of these mites are discussed; however, feeding preferences have not been clarified.
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Houck, Tyler, Megan Boyd, Erick Balde, and Elena Keeling. "Investigation of Blood Cell Populations in the Development and Regeneration of a Colonial Ascidian." FASEB Journal 30, S1 (April 2016). http://dx.doi.org/10.1096/fasebj.30.1_supplement.1036.7.
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Botrylloides violaceus is a colonial marine ascidian capable of undergoing whole body regeneration after removal of all tissues except the peripheral vasculature. As chordates, colonial ascidians are more closely related to vertebrates than other model organisms for whole body regeneration. There is evidence that one or more populations of stem cells are present in the circulating blood of B. violaceus; these cells may also be involved in asexual reproduction by budding. We are studying changes in blood composition during development and regeneration. Hemoblasts, a type of undifferentiated blood cell, have been implicated as stem cells in botryllid ascidians and are therefore of special interest. Comparisons of blood composition at several developmental stages are in progress. Preliminary data suggest that hemoblast composition of B. violaceus blood is stable during the regenerative process. Further, we show dramatically higher relative amounts of hemoblasts in the blood of B. violaceus compared to reported amounts in related species. This high percentage of hemoblasts may be associated with the readiness of B. violaceus to undergo regeneration at any stage of its life cycle.Support or Funding InformationCSU Council on Ocean Affairs, Science & Technology (COAST); Biological Sciences Department, California Polytechnic State University
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Jiménez-Merino, Juan, Isadora Santos de Abreu, Laurel S. Hiebert, Silvana Allodi, Stefano Tiozzo, Cintia M. De Barros, and Federico D. Brown. "Putative stem cells in the hemolymph and in the intestinal submucosa of the solitary ascidian Styela plicata." EvoDevo 10, no. 1 (November 25, 2019). http://dx.doi.org/10.1186/s13227-019-0144-3.
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Abstract Background In various ascidian species, circulating stem cells have been documented to be involved in asexual reproduction and whole-body regeneration. Studies of these cell population(s) are mainly restricted to colonial species. Here, we investigate the occurrence of circulating stem cells in the solitary Styela plicata, a member of the Styelidae, a family with at least two independent origins of coloniality. Results Using flow cytometry, we characterized a population of circulating putative stem cells (CPSCs) in S. plicata and determined two gates likely enriched with CPSCs based on morphology and aldehyde dehydrogenase (ALDH) activity. We found an ALDH + cell population with low granularity, suggesting a stem-like state. In an attempt to uncover putative CPSCs niches in S. plicata, we performed a histological survey for hemoblast-like cells, followed by immunohistochemistry with stem cell and proliferation markers. The intestinal submucosa (IS) showed high cellular proliferation levels and high frequency of undifferentiated cells and histological and ultrastructural analyses revealed the presence of hemoblast aggregations in the IS suggesting a possible niche. Finally, we document the first ontogenetic appearance of distinct metamorphic circulatory mesenchyme cells, which precedes the emergence of juvenile hemocytes. Conclusions We find CPSCs in the hemolymph of the solitary ascidian Styela plicata, presumably involved in the regenerative capacity of this species. The presence of proliferating and undifferentiated mesenchymal cells suggests IS as a possible niche.
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Nourizadeh, Shane, Susannah Kassmer, Delany Rodriguez, Laurel S. Hiebert, and Anthony W. De Tomaso. "Whole body regeneration and developmental competition in two botryllid ascidians." EvoDevo 12, no. 1 (December 2021). http://dx.doi.org/10.1186/s13227-021-00185-y.
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Abstract Background Botryllid ascidians are a group of marine invertebrate chordates that are colonial and grow by repeated rounds of asexual reproduction to form a colony of individual bodies, called zooids, linked by a common vascular network. Two distinct processes are responsible for zooid regeneration. In the first, called blastogenesis, new zooids arise from a region of multipotent epithelium from a pre-existing zooid. In the second, called whole body regeneration (WBR), mobile cells in the vasculature coalesce and are the source of the new zooid. In some botryllid species, blastogenesis and WBR occur concurrently, while in others, blastogenesis is used exclusively for growth, while WBR only occurs following injury or exiting periods of dormancy. In species such as Botrylloides diegensis, injury induced WBR is triggered by the surgical isolation of a small piece of vasculature. However, Botryllus schlosseri has unique requirements that must be met for successful injury induced WBR. Our goal was to understand why there would be different requirements between these two species. Results While WBR in B. diegensis was robust, we found that in B. schlosseri, new zooid growth following injury is unlikely due to circulatory cells, but instead a result of ectopic development of tissues leftover from the blastogenic process. These tissues could be whole, damaged, or partially resorbed developing zooids, and we defined the minimal amount of vascular biomass to support ectopic regeneration. We did find a common theme between the two species: a competitive process exists which results in only a single zooid reaching maturity following injury. We utilized this phenomenon and found that competition is reversible and mediated by circulating factors and/or cells. Conclusions We propose that WBR does not occur in B. schlosseri and that the unique requirements defined in other studies only serve to increase the chances of ectopic development. This is likely a response to injury as we have discovered a vascular-based reversible competitive mechanism which ensures that only a single zooid completes development. This competition has been described in other species, but the unique response of B. schlosseri to injury provides a new model to study resource allocation and competition within an individual.
Dissertations / Theses on the topic "Ascidies – Reproduction (biologie)"
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Ricci, Lorenzo. "A new model to study alternative developments : asexual propagation and regeneration in the basal chordate Botryllus schlosseri." Electronic Thesis or Diss., Paris 6, 2015. http://www.theses.fr/2015PA066683.
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Chez l’ascidie coloniale Botryllus schlosseri, en plus de l’embryogénèse existent deux voies de développement aboutissant à la production de la même structure : l’organisme adulte ou zooide. Ces développements alternatifs ont lieu lors de processus biologiques distincts : le bourgeonnement palléal (BP) et le bourgeonnement vasculaire (BV). Le BP est un processus de multiplication asexuée présentant une ontogénèse stéréotypée. En revanche, le BV est un phénomène régénératif, induit dans les vaisseaux sanguins de la colonie par l’ablation de tous les zooides et bourgeons palléaux. Mes travaux de recherche ont eu pour objectif de caractériser les bases moléculaires et cellulaires régissant le BP et le BV chez B. schlosseri. L’étude de gènes marqueurs des lignées méso-, endo- et ectodermiques a révélé l’existence de territoires présomptifs pour chacune de ces lignées, dès les premiers stades du BV et du BP, et suggéré l’existence d’un programme unique aux deux processus. Les lignées neurales et musculaires ont été étudiées plus en détail lors du BP, indiquant un double rôle potentiel, neuro- et myo-génétique, au tube dorsal, une structure jusqu’à présent uniquement associée au système nerveux. Une caractérisation morphologique poussée a mené à l’identification de stades précoces stéréotypés du BV lors de la régénération. Enfin, l’analyse de transcriptomes de différents stades du BP et de la régénération ont initié l’étude non biaisée des bases moléculaires du bourgeonnement chez Botryllus. L’objectif à long terme de ces travaux est de décrypter les bases moléculaires et génétiques facilitant, chez les métazoaires, l’évolution de voies de développement alternativesIn addition to embryogenesis, the colonial ascidians Botryllus schlosseri evolved two alternative developmental pathways leading to the same final structure: the adult body, or zooid. These non-embryonic ontogenesis occur during distinct biological processes: palleal budding (PB) and vascular budding (VB). PB is a process of asexual propagation, with a very stereotyped morphogenesis. Conversely, VB is a purely regenerative phenomenon, induced in the vascular system of the colony by the ablation of all zooids and palleal buds. My research work followed the objective to characterize the molecular and cellular basis of both PB and VB in B. schlosseri. The study of meso-, endo- and ectodermal lineage marker genes revealed the existence of presumptive territories of these lineages in the early palleal and vascular buds and that a single developmental program was launched in both VB and PB. Neural and muscle fates were studied in more detail for PB, indicating a potential double function, both neuro- and myo-genic for the dorsal tube, a structure so far associated with the nervous system only. A detailed morphological description of VB allowed to identify stereotyped stages during early regeneration. Eventually, a transcriptomic characterization of early VB and PB processes initiated an unbiased study of the molecular basis underlying the budding phenomenon in Botryllus. The overall goal of these research works is to unravel the molecular and genetic basis that facilitated, in Botryllus and globally in metazoan, the evolution of alternative developmental pathways
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Evans, Rowan. "Reproduction of the unitary, larviparous ascidian Dendroda grossularia." Thesis, University of Liverpool, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.260360.
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Pineda, Torres Mari Carmen. "A global wanderer: Biology, phylogeography and resilience of the introduced ascidian "Styela plicata" / Història d’una introducció global: biologia, filogeografia i susceptibilitat a factors ambientals de l’ascidi cosmopolita "Styela alicata"." Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/101200.
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"Styela plicata" is a solitary ascidian introduced all around the world by ship traffic and seems to have many of the required features to become invasive. The main goal of this PhD thesis was to increase our knowledge on the genetic composition of this species, its reproductive features and its capacity to cope with stress during early life-history stages and adulthood. Results indicate that S. plicata is an ancient introduced species that has been travelling around the globe through maritime transport for centuries. It inhabits harbors, marinas and artificial structures, tolerating high concentrations of pollutants. Adults can respond to moderate levels of stressors by adjusting the production of stress-related proteins, but early stages are comparatively much more vulnerable to the harsh conditions that characterize the habitats where this species thrives. A prolonged reproductive period allows S. plicata to exploit temporal windows of favorable conditions and confers a competitive advantage compared to organisms with limited, seasonal reproduction events. Moreover, high genetic variability and the continual presence of larvae also guarantee further reintroduction events and spreading via ship traffic. At present, the distribution of S. plicata appears to be limited by high temperatures, low salinities and other non-investigated factors such as competition and predation. Further studies should determine the dynamics of the few populations co-habiting with native communities to pinpoint all the factors regulating the spread of this species outside enclosed environments.La ascidia Styela plicata ha sido introducida alrededor del mundo y parece presentar las características necesarias para convertirse en invasora. El objetivo principal de esta tesis Doctoral ha sido incrementar nuestro conocimiento sobre la composición genética de la especie, sus características reproductoras y su habilidad para tolerar condiciones estresantes como adulto pero también a lo largo de las primeras etapas del cliclo de vida. Los resultados han indicado que S. plicata es una introducción antigua, dado que la especie ha estado viajando alrededor del mundo durante los últimos siglos gracias al transporte marítimo. Esta especie habita en puertos, marinas y otras estructuras artificiales, y tolera altas concentraciones de contaminantes. Los adultos pueden responder a niveles moderados de estresores ajustando la producción de proteínas de estrés, pero los primeros estadios del desarrollo son mucho más vulnerables a las condiciones que caracterizan los ambientes en que la especie habita. Un periodo reproductor extenso permite a la especie explotar ventanas temporales de condiciones favorables y confiere a la especie una ventaja competitiva frente a otros organismos con reproducción estacional. Además, la elevada variabilidad genética y la presencia continua de larvas en la columna de agua, garantiza también eventos de reintroducción secundarios y por tanto la dispersión de la especie vía tráfico marítimo. Actualmente, la distribución de S. plicata parece estar limitada por temperaturas elevadas, bajas salinidades y otros factores aún por investigar tales como la competencia y la depredación. La dinámica de las escasas poblaciones en que la especie cohabita con comunidades nativas debería ser estudiada, para detectar los factores que regularían la dispersión de la especie afuera de los ambientes confinados en que actualmente la encontramos.
Book chapters on the topic "Ascidies – Reproduction (biologie)"
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Stewart-Savage, J., Anne Stires, and Philip O. Yund. "Environmental Effect on the Reproductive Effort of Botryllus schlosseri." In The Biology of Ascidians, 311–14. Tokyo: Springer Japan, 2001. http://dx.doi.org/10.1007/978-4-431-66982-1_49.
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Tsuda, Motoyuki, Mahito Ohkuma, Masashi Nakagawa, and Yasuo Katagiri. "Light Regulated GnRH Neurons in Biological Clock for Reproduction in the Ascidian, Halocynthia roretzi." In The Biology of Ascidians, 131–36. Tokyo: Springer Japan, 2001. http://dx.doi.org/10.1007/978-4-431-66982-1_21.
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Kawamura, Kazuo. "Molecular and Cellular Advantage of Transdifferentiation System for Asexual Reproduction of the Tunicate, Polyandrocarpa misakiensis." In The Biology of Ascidians, 293–99. Tokyo: Springer Japan, 2001. http://dx.doi.org/10.1007/978-4-431-66982-1_46.
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