Relevant bibliographies by topics / Ascidians

Academic literature on the topic 'Ascidians'

Author: Grafiati
Published: 4 June 2021
Last updated: 20 February 2023

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Journal articles on the topic "Ascidians"

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Morton, Brian, and Grete E. Dinesen. "The biology and functional morphology of Modiolarca subpicta (Bivalvia: Mytilidae: Musculinae), epizoically symbiotic with Ascidiella aspersa (Urochordata: Ascidiacea), from the Kattegat, northern Jutland, Denmark." Journal of the Marine Biological Association of the United Kingdom 91, no. 8 (December 15, 2010): 1637–49. http://dx.doi.org/10.1017/s0025315410001980.

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This study of the little known north-eastern Atlantic mytilid Modiolarca subpicta suggests a more intimate relationship with ascidians and, especially, Ascidiella aspersa, than has hitherto been appreciated. Both live for ~18 months and the reproductive cycle of both is approximately co-ordinated so that juvenile ascidians become available as hosts to the settling spat of the symbiotically epizoic M. subpicta each summer. Settling spat of M. subpicta are thought to be attracted to the exhalant flow from the ascidian's anal siphon. After the ascidian's death, the liberated mussels may adopt a wandering, free-living, lifestyle they have occasionally been reported to pursue. Anatomically, M. subpicta is of the typical mytilid plan, albeit simplified commensurate upon its normal lifestyle of protective envelopment within the host's tunic. The foot, however, is highly mobile and in addition to being used for locomotion, especially in juveniles, is responsible for the planting of byssal threads, typically dorsally above the shell, so that each individual stimulates the ascidian to produce an epidermal pocket into which it manœuvres itself and reposes, securely attached, but dorsal side down Modiolarca subpicta, epizoic in the tests of ascidians, could have evolved from a more isomyarian, equivalve, ancestor via a nestling, epibyssate, Trichomusculus-like shaped intermediary with ventral flattening and, hence, stability characteristic of the more familiar heteromyarian mytilids of rocky shores and lotic freshwaters being achieved through living dorsal side down.
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Tatian, M., R. J. Sahade, M. E. Doucet, and G. B. Esnal. "Ascidians (Tunicata, Ascidiacea) of Potter Cove, South Shetland Islands, Antarctica." Antarctic Science 10, no. 2 (June 1998): 147–52. http://dx.doi.org/10.1017/s0954102098000194.

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Certain physical factors, substrate type and ice action appear to be important determinants for ascidian distribution. Three different substrate types were sampled at depths between 0–30 m by SCUBA diving: soft bottoms, hard bottoms and moraine deposits. The species found were Aplidium radiatum, Synoicum adareanum, Distaplia cylindrica, Sycozoa gaimardi, Sycozoa sigillinoides, Tylobranchion speciosum, Corella eumyota, Ascidia challengeri, Cnemidocarpa verrucosa, Styela wandeli, Dicarpa insinuosa, Pyura bouvetensis, Pyura discoveryi, Pyura obesa, Pyura setosa, Molgula enodis and Molgula pedunculata. Highest diversity and patchy distribution was found in less stringent environments, where epibiosis is a commmon phenomenon on stolidobranch ascidians. Differences in stalk development were found in the most abundant species Molgula pedunculata and Cnemidocarpa verrucosa. Ice action may be the main factor that determines the absence of ascidians above 15 m in all the stations sampled.
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KNEER, DOMINIK, FRANCOISE MONNIOT, THOMAS STACH, and MARJOLIJN J. A. CHRISTIANEN. "Ascidia subterranea sp. nov. (Phlebobranchia: Ascidiidae), a new tunicate belonging to the A. sydneiensis Stimpson, 1855 group, found as burrow associate of Axiopsis serratifrons A. Milne-Edwards, 1873 (Decapoda: Axiidae) on Derawan Island, Indonesia." Zootaxa 3616, no. 5 (February 22, 2013): 485–94. http://dx.doi.org/10.11646/zootaxa.3616.5.5.

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A new tunicate, Ascidia subterranea sp. nov., was found in burrows of the axiid crustacean Axiopsis serratifrons on De-rawan Island, Indonesia. It differs from other ascidians in its habitat as well as numerous morphological peculiarities which are described in detail. The shrimp Rostronia stylirostris Holthuis, 1952 was found inside A. subterranea sp. nov., and 4 species of bivalves, 3 species of polychaetes, 1 gastropod, 1 polyplacophoran and 1 sponge species were found as burrow associates besides the ascidian.
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Malintoi, Adrianus, Inneke F. M. Rumengan, Kakaskasen A. Roeroe, Veibe Warouw, Ari B. Rondonuwu, and Medy Ompi. "KOMUNITAS ASCIDIA DI PESISIR MALALAYANG DUA, TELUK MANADO, SULAWESI UTARA." JURNAL PESISIR DAN LAUT TROPIS 8, no. 1 (January 15, 2020): 39. http://dx.doi.org/10.35800/jplt.8.1.2020.27403.

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Field survey on ascidian community was conducted along the coastal area of Malalayang Dua in order to find out species of ascidia, species abundance, and ascidian substrates. A survey method and quadrant transects were applied. Pictures were taken, while species and their substrates were sampled. Species identification was based on morphological characteristics, while substrate type identification was based on ascidian species attachment. The results shows that 21 ascidian species were found in the the coastal of Malalayang Dua. Didemnum molle was the highest abundant species in the area, followed by Polycarpa aurata, Polycarpa sp.4. and Polycarpa sp.2.. Dead coral algaes (DCA) were found to be the most preferred substrates by ascidians in the area. Keywords : ascidia, species, substrate, distribution, and abundance Survei lapangan terhadap komunitas ascidia dilakukan di pesisir Malalayang Dua untuk mendapatkan data jenis, kelimpahan, dan substrat ascidia. Metode yang digunakan yaitu metode survei jelajah dan transek kuadran. Identifikasi jenis ascidia dilakukan berdasarkan karakteristik morfologi. Hasil penelitian ditemukan ada 21 jenis ascidia. Substrat jenis death coral algae (DCA) merupakan substrat yang paling banyak ditempati ascidia. Kelimpahan ascidia tertinggi adalah Didemnum molle di pesisir Malalayang Dua, diikuti oleh Polycarpa aurata, Polycarpa sp.4. dan Polycarpa sp.2. Death coral alga (DCA) ditemukan sebagai substrat yang paling disukai oleh ascidia di daerah itu. Kata Kunci : ascidia, spesies, substrat, distribusi, dan kelimpahan
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Sargent, P. S., J. F. Hamel, and A. Mercier. "The life history and feeding ecology of velvet shell, Velutina velutina (Gastropoda: Velutinidae), a specialist predator of ascidians." Canadian Journal of Zoology 97, no. 12 (December 2019): 1164–76. http://dx.doi.org/10.1139/cjz-2018-0327.

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Velvet shell, Velutina velutina (Müller, 1776), is a specialist predator of ascidians, like other members of the gastropod family Velutinidae. Globally, invasive ascidians have become problematic, ecologically and economically, yet ecological knowledge of velutinids remains limited. This study outlines the life history and feeding ecology of V. velutina in eastern Canada based on laboratory work complemented by field observations. The life history of V. velutina is closely linked with ascidians, which serve as prey and protection for their egg capsules. Egg capsules were embedded within tunics of Aplidium glabrum (Verrill, 1871) and Ascidia callosa Stimpson, 1852, with a preference for the latter. Seasonal behavioural shifts were consistent annually and corresponded with seawater temperature cycles. Feeding dominated during the coldest months (January–May), growth occurred as water temperature increased to the annual maximum (June and July), transitioning to mating during the warmest period (July–August), and egg capsule deposition dominated as water temperature declined (November–January). Larvae hatched between January and July after 2–4 months of development. Velutina velutina preyed on all ascidian species presented during this study, including golden star tunicate, Botryllus schlosseri (Pallas, 1766), and vase tunicate, Ciona intestinalis (Linnaeus, 1767), two non-indigenous species, although solitary species were preferred.
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Rocha, Rosana Moreira, Edlin Guerra-Castro, Carlos Lira, Sheila Marquez Pauls, Ivan Hernández, Adriana Pérez, Adriana Sardi, et al. "Inventory of ascidians (Tunicata, Ascidiacea) from the National Park La Restinga, Isla Margarita, Venezuela." Biota Neotropica 10, no. 1 (March 2010): 209–18. http://dx.doi.org/10.1590/s1676-06032010000100021.

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Although ascidians form a conspicuous part of sessile assemblages in the Caribbean, no specialized inventories have been developed in Venezuela, except for a list of 15 species reported from Margarita Island (1984). Here we present the results of a taxonomic workshop held in the Universidad de Oriente, Boca del Rio, Margarita Island during April 20-25 of 2009, sponsored by the NaGISA-Caribbean Sea program. La Restinga National park was surveyed and we found 29 species belonging to 19 genera and 10 families. The most abundant colonial species were Clavelina oblonga, Aplidium accarense, Polyclinum constellatum, Distaplia bermudensis, Symplegma rubra, S. brakenhielmi, Botrylloides nigrum and Ecteinascidia turbinata. Among the solitary ascidians Phallusia nigra, Ascidia curvata, Microcosmus exasperatus, Styela canopus, Styela sp.1 and Styela sp. 2 were the most abundant. The ascidian diversity in this lagoon is one of the highest for similar habitats in the Caribbean and seven species are new registers for Venezuela (Ascidia curvata, Ecteinascidia styeloides, Aplidium accarense, Distaplia stylifera, Trididemnum orbiculatum, Symplegma rubra, and S. brakenhielmi). One point of concern for the conservation of la Restinga National Park is the presence of possible introduced species, and some management procedures are suggested.
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Dou, Xiaoju, and Bo Dong. "Origins and Bioactivities of Natural Compounds Derived from Marine Ascidians and Their Symbionts." Marine Drugs 17, no. 12 (November 28, 2019): 670. http://dx.doi.org/10.3390/md17120670.

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Marine ascidians are becoming important drug sources that provide abundant secondary metabolites with novel structures and high bioactivities. As one of the most chemically prolific marine animals, more than 1200 inspirational natural products, such as alkaloids, peptides, and polyketides, with intricate and novel chemical structures have been identified from ascidians. Some of them have been successfully developed as lead compounds or highly efficient drugs. Although numerous compounds that exist in ascidians have been structurally and functionally identified, their origins are not clear. Interestingly, growing evidence has shown that these natural products not only come from ascidians, but they also originate from symbiotic microbes. This review classifies the identified natural products from ascidians and the associated symbionts. Then, we discuss the diversity of ascidian symbiotic microbe communities, which synthesize diverse natural products that are beneficial for the hosts. Identification of the complex interactions between the symbiont and the host is a useful approach to discovering ways that direct the biosynthesis of novel bioactive compounds with pharmaceutical potentials.
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Macpal, Yuliana, Veibe Warouw, Deiske A. Sumilat, James J. H. Paulus, Natalie D. C. Rumampuk, and Reni L. Kreckhoff. "AKTIVITAS ANTIBAKTERI DAN ANTI-UV BEBERAPA ASCIDIAN DARI PERAIRAN PANGALISANG BUNAKEN." JURNAL PESISIR DAN LAUT TROPIS 7, no. 3 (July 23, 2019): 271. http://dx.doi.org/10.35800/jplt.7.3.2019.26019.

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Ascidians are sesile marine invertebrates that have bioactive compounds such as antibacterial and anti-UV. The purpose of this study is to determine the antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria and to test the anti-UV activity of the ascidian water fraction. Antibacterial activity test was carried out using the diffusion method (disc diffusion Kirby & Bauer) and the water fraction of ascidian that showing antibacterial activity tested in a UV spectrophotometer to see the anti-UV activity. Results of the study were obtained 4 types of ascidians extracted from partitioned into water fraction, n-hexane fraction, methanol fraction. All three fractions were tested for antibacterial activity and the result showed that there were antibacterial activities of ascidian extract Clavelina sp. against both test bacteria with inhibition of S. aureus and E. coli with strong categories. Ascidian Phlebobranch sp. showed the presence of antibacterial activity with inhibition of S. aureus and E. coli with very strong categories (16,6 mm). extract Eudistoma sp. showed the presence of antibacterial activity with inhibition S. aureus and E. coli in the medium category (9 mm). The water fraction found active in antibacterial testing is then tested using a UV spectrophotometer for anti UV testing, the result show that water fraction of the four ascidians can absorb UV-B (290-320nm) and UV-A ( 320-400nm).Keywords : Ascidian, Antibacterial, Partition, Anti- UV.
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Casertano, Marcello, Marialuisa Menna, and Concetta Imperatore. "The Ascidian-Derived Metabolites with Antimicrobial Properties." Antibiotics 9, no. 8 (August 13, 2020): 510. http://dx.doi.org/10.3390/antibiotics9080510.

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Among the sub-phylum of Tunicate, ascidians represent the most abundant class of marine invertebrates, with 3000 species by heterogeneous habitat, that is, from shallow water to deep sea, already reported. The chemistry of these sessile filter-feeding organisms is an attractive reservoir of varied and peculiar bioactive compounds. Most secondary metabolites isolated from ascidians stand out for their potential as putative therapeutic agents in the treatment of several illnesses like microbial infections. In this review, we present and discuss the antibacterial activity shown by the main groups of ascidian-derived products, such as sulfur-containing compounds, meroterpenes, alkaloids, peptides, furanones, and their derivatives. Moreover, the direct evidence of a symbiotic association between marine ascidians and microorganisms shed light on the real producers of many extremely potent marine natural compounds. Hence, we also report the antibacterial potential, joined to antifungal and antiviral activity, of metabolites isolated from ascidian-associate microorganisms by culture-dependent methods.
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White, Kristine, Louis Ambrosio, and Christa Edwards. "Anthropogenic Sound in the Sea: Are Ascidians Affected?" Gulf and Caribbean Research 32 (2021): 1–7. http://dx.doi.org/10.18785/gcr.3201.02.

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Sound pollution in the marine environment has been increasing largely due to anthropogenic sources such as vessel traffic, coastal development, fossil fuel extraction, and military exercises. Studies determining the effects of anthropogenic sound on marine organisms have mostly focused on vertebrates, namely fish and marine mammals; however, less research has been done to study the effects of sound on marine invertebrates. The goal of this research is to examine the effect of anthropogenic sound on the ascidian Styela plicata (Lesueur, 1823) in Tampa Bay, FL. A total of 48 ascidians were collected from 2 sites with differing amounts of boat traffic and thus different anthropogenic soundscapes. Ascidians were individually exposed to 3 separate stimuli: a recording of a boat motor, a song recording, and a water current to simulate turbulence. Ascidian reactions were recorded as the frequency of siphon closing events and the length of time the siphons remained closed after disturbance. Ascidians from both sites increased the frequency and longevity of siphon closure events in response to anthropogenic stimuli but showed only a minor difference in response between sample sites. Research into the effect of anthropogenic sound on invertebrates such as ascidians and their symbionts may provide a better understanding of larger scale ecological impacts from such disturbances.
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Dissertations / Theses on the topic "Ascidians"

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Bromley, Candice Leigh. "The chemistry of Algoa Bay ascidians." Thesis, Rhodes University, 2016. http://hdl.handle.net/10962/d1020606.

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This thesis investigates the chemistry of 25 ascidian species collected from Algoa Bay, South Africa with a concerted focus on metal accumulation by these ascidians and the possible interaction of these metals with ascidian metabolites. Chapter 2 details the screening techniques employed to establish the presence of nitrogenous metabolites (1H- 15N HMBC), hyper-accumulated metal ions (ICP-MS) and potential metal ion/ ascidian metabolite complexes (LC-ICP-MS/ESI-MS). Unfortunately, exhaustive attempts to detect intact metal ion/ascidian metabolite complexes through the use of liquid chromatography with parallel inductively coupled plasma mass spectrometry/electrospray mass spectrometry (LC-ICPMS/ ESI-MS) were unsuccessful. However, the LC-ICP-MS/ESI-MS data obtained for the crude organic extracts of six of the Algoa Bay ascidian species, Distaplia skoogi, Aplidium monile, Aplidium sp., Didemnum sp., Leptoclindines sp. and Polycitor sp. enabled identification of a number of ten halogenated metabolites, namely the indoles 2.28-2.30, and the tyramine and tyrosine derivatives (2.31-2.33, 2.41, 2.43, 2.44 and 2.46), within the ascidian extracts. This study confirmed that LC-ICP-MS/ESI-MS is a powerful tool for the dereplication of halogenated metabolites in complex mixtures especially where these compounds are present in very small amounts. This study is also the first report of these compounds (eight of which are known) in African ascidians. Compounds 2.32 and 2.46 have not been reported before from a marine source. Compounds 2.28-2.30 and 2.33 were present in sufficient amounts in the respective ascidian extracts to allow their isolation and structure elucidation using standard spectroscopic techniques Chapter 3 explores the ability of ascidians to accumulate a wide range of metal ions at concentrations which are often orders of magnitude higher than those of the surrounding sea water. Inductively coupled plasma mass spectrometry (ICP-MS) was used to determine the total ion concentrations of 24 metals in 25 Algoa Bay ascidian species. To the best of our knowledge this is the largest and most extensive investigation of metal concentrations in a group of different ascidians occurring in the same area. Hypotheisizing that the metal ion concentrations for each ascidian specimen screened may represent a unique fingerprint for each specimen principal component analysis (PCA) was used in an attempt to establish whether there were spatial, temporal or phylogenetic relationships associated with the metal concentration fingerprints of the ascidians that formed part of this study. The PCA results showed that there were no statistically significant relationships between ascidian metal ion concentrations and either the collection year or the collection site of the ascidians. However, species from the family Didemnidae provided the clearest statistical evidence supporting a phylogenetic relationship between these ascidians and their hyperaccumulated metal ion profiles. Furthermore, these results suggested that ascidian species are indeed actively concentrating metal ions from the surrounding sea water and are not simply sinks for passively accumulated metal ions. Interestingly, the concentration of vanadium in the set of ascidians studied did not appear to correlate with any of the other metals accumulated by these ascidians suggesting that there is possibly a unique method employed for the accumulation of vanadium by ascidians. Chapter 4 investigated this possibility further after the nucleosides 4.10, 4.11, 4.13, 4.15, 4.17 and 4.40 were isolated from the vanadium accumulating ascidian Aplidium monile. Studies into the interactions between nucleosides and vanadyl are unfortunately rare and usually qualitative in nature with limited information provided about the stability or structures of the complexes formed. The vanadyl accumulating aplousobranch ascidians e.g. Aplidium monile dominated our study of Algoa Bay ascidians therefore providing us with the rationale to investigate the relatively little studied binding ability and stability of vandyl-nucleoside complexes. Potentiometric studies were conducted to determine the stability constants of complexes formed between the oxovanadium ion vanadyl (VO2+) and the commercially available nucleosides 4.10-4.14. The data afforded by this analysis clearly confirmed the complexity of the vanadyl/nucleoside complexation and suggested that guanosine (4.12) formed the most stable complex with oxovanadium ions. We were also able to establish a third protonation constant for the hydroxyl moiety in 4.12 with a logK 8.87 which has not been previously reported. Finally, Chapter 5 revisited the cytoxicity two Algoa Bay ascidians, Clavelina sp. and Atriolum marinense the extracts from which produced promising bioactivity results in previous studies against oesophageal cancer cells. The HP-20 fractionated extracts of Clavelina sp. and Atriolum marinense proved to be similalrly cytotoxic to breast cancer cells. With the exception for the 100% acetone(aq)fractions the NMR data for both species suggested that most active non polar fractions were dominated by what appeared to be structurally unremarkable fatty acid glycerides and as such were not pursued further. Purification of the 100% acetone(aq)fraction of A. marinense resulted in the isolation of a styrene trimer, 5.1, common to both ascidian extracts. The NMR simulation software WIN-DAISY was employed to confirm the structure of 5.1. Attempts to establish if 5.1 was an isolation artefact or a product of marine pollution were inconclusive
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Parker-Nance, Shirley. "Aplousobranch ascidians (Tunicata: Ascidiacea) from Southern Africa." Thesis, University of Port Elizabeth, 2003. http://hdl.handle.net/10948/311.

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The ascidian (subphylum Tunicata: class Ascidiacea) fauna along the southern African coast constitutes an important component of the sessile benthic reef fauna. Little is known of the species composition, biodiversity and distribution of ascidians on southern African intertidal and subtidal reefs. Past research on the ascidian fauna of South Africa was sporadic and limited, with only about one hundred and seventy species recorded during the last one hundred and twenty years. This is the first taxonomic study undertaken by a South African resident scientist. The study focused on six genera in four families (Euherdmaniidae, Polyclinidae, Pseudodistomidae and Didemnidae) belonging to the class Ascidiacea and suborder Aplousobranchia. Five species new to science, two Polyclinum, two Pseudodistoma and one Polysyncraton species are described. New additional information on the distribution of five species previously known to science, including one recorded for the first time along the South African coast, is presented. A literature review and comparison of the taxonomic important characteristics is made of all species known globally for the six genera. These six genera comprise twelve Euherdmania, fifteen Aplidiopsis, forty Polyclinum thirty-one Pseudodistoma, six Atriolum and sixty-eight Polysyncraton species.
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Davis, Rohan Andrew, and davis_rohan@hotmail com. "Chemical Investigations of Great Barrier Reef Ascidians - Natural Product and Synthetic Studies." Griffith University. School of Science, 2000. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030102.104858.

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This thesis describes the chemical investigations of several ascidian species collected from the Great Barrier Reef, Queensland, Australia. The thesis is divided into two separate components, Part A focuses on the isolation and structure elucidation of 11 previously undescribed ascidian metabolites. All structures were assigned using a combination of spectroscopic and/or chemical methods. Part B relates to the isolation and chemical conversion of a natural product to a combinatorial template. The natural product template was subsequently used in the generation of a solution-phase combinatorial chemistry library. A further two combinatorial libraries were generated from a synthesised model compound that was related to the natural product template. Part A. Investigation of Aplidium longithorax collected from the Swains Reefs resulted in the isolation of two new para-substituted cyclofarnesylated quinone derived compounds, longithorones J (30) and K (31). The former compound had its absolute stereochemistry determined by the advanced Mosher method. From an Aplidium longithorax collected from Heron Island, two new cyclofarnesylated hydroquinone compounds, longithorols C (46) and D (47) and a novel macrocyclic chromenol, longithorol E (48) were isolated. Longithorol C (46) had its absolute stereochemistry determined by the advanced Mosher method. Chemical investigation of the deep-purple colonial ascidian, Didemnum chartaceum collected from Swains Reefs led to the isolation of five new lamellarin alkaloids, which included the 20-sulfated derivatives of lamellarins B (94), C (95) and L (96), the 8-sulfated derivative of lamellarin G (97) and the non-sulfated compound, lamellarin Z (98). The known lamellarins A (63), B (80), C (64), E (65), G (67), and L (71) plus the triacetate derivatives of lamellarin D (82) and N (83) were also isolated. An aberration in the integration of signals in the 1H NMR spectra of the 20-sulfated derivatives (94-96) led to NMR relaxation studies. T1 values were calculated for all protons in the sulfated lamellarins (94-97) and their corresponding non-sulfated derivatives (80, 64, 71, 67). The protons ortho to the sulfate group in compounds (94-97) had T1 values up to five times larger than the corresponding protons in their non-sulfated derivatives (80, 64, 71, 67). A specimen of Eudistoma anaematum collected from Heron Island was shown to contain a new b-carboline alkaloid, eudistomin V (130), in addition to the two known metabolites, eudistomin H (105) and I (106). Part B. The known natural products, 1,3-diphenethylurea (29), 1,3-dimethylxanthine (30), 1,3-dimethylisoguanine (31) and the salts of tambjamine C (16), E (18) and F (19) were isolated from the ascidian, Sigillina signifera collected in Blue Lagoon, Lizard Island. Base hydrolysis on mixtures of the salts of tambjamine C (16), E (18) and F (19) resulted in the production of 4-methoxy-2,2-bipyrrole-5-carbaldehyde (26). This natural product template (26) was used in the generation of an enamine combinatorial chemistry library (98, 103-111) using solution-phase parallel synthesis. The biaryl compound, 4-(2-thienyl)-1H-pyrrole-2-carbaldehyde (59) was successfully synthesised using Suzuki-Miyaura coupling conditions and subsequently used as a template in the generation of an amine (67, 77, 80-87) and imine (78, 92-95) combinatorial library using solution-phase parallel synthesis.
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Goostrey, Anna. "Aspects of vegetative reproduction and developmental genetics in Diplosoma listerianum (Tunicata, Aplousobranchiata)." Thesis, University of Aberdeen, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367481.

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Hox and ParaHox genes are groups of key developmental transcription factors that are highly conserved throughout the Metazoa. Their order of expression along the body axis of an animal is not only highly conserved between different organisms, but is also collinear to the arrangement of individual genes along the chromosome. Studies of these developmental control genes can give valuable insights into the evolution of body plans. A total of 7 homeobox containing genes (dpl1-dpl7) were isolated form the D. listerianum genome. Four of these were members of the Hox gene family and of the ParaHox gene family. Initial fragments were isolated using the method of degenerate PCR with primers designed from the highly conserved amino acid sequence of the 1st and 3rd helix of the homeodomain. Short fragments limit gene characterisation and as such, regions flanking the degenerate PCR products were isolated, using inverse PCR, 3' and 5' RACE PCR. Phylogenetic relationships of the genes are also examined. Dpl1 exhibited high identities with the arthropod Antennapedia and the vertebrate Hox6 and Hox 7 paralogue groups. Phylogenetic analysis showed dpl1 to be more closely related to the Hox6 than to the Hox7 group genes. Dpl2 shares high identity with members of the Hox5/Scr paralogous group. Dpl3 has a high level of homology to the C. intestinalis gene CiIPF1. The Dpl3 homeodomain shared high identity with the ascidian H. roretzi and H. curvata cdx genes (Hr-cad and Hec-cdx, respectively), however differences in the hexapeptide regions, indicated high divergence of these genes in the ascidians. Dpl5 possessed features characteristic of posterior Hox genes and was most closely related to the C. intestinalis CiHbox5 gene. Dpl6 shared features common to the Hox 4 paralogous group Gsx ParaHox groups.
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Da, Silva Liberio Michelle. "Chemical and Biological Investigations of Anticancer Compounds from Australian Ascidians." Thesis, Griffith University, 2014. http://hdl.handle.net/10072/365813.

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Nature is the main source of anticancer agents with about 60% of the current anticancer drugs originating in some way from natural products. Many cytotoxic natural products have been isolated from marine invertebrates. One group of marine animals that have made significant contributions is the tunicates or ascidians. Ascidians belonging to the family Didemnidae are known to be a prolific and rich source of new chemical entities with biological activity. This study was divided into two main components. In the first part, Didemnid ascidians collected from the Great Barrier Reef (GBR) were investigated for their chemical diversity using spectroscopic and spectrometric techniques. In part two, an ascidian drug discovery screening library was generated and subsequently used to identify cytotoxic or cytostatic compounds in prostate (LNCaP) and breast (MDA-MB-231) cancer cells. The ascidian natural products isolated in part 1 were all tested in these cancer cell lines. Moreover, one of the cytotoxic compounds identified from the screening studies was subjected to mechanism of action studies.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Biomolecular and Physical Sciences
Science, Environment, Engineering and Technology
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Stacey, Joy E. "The ecophysiology of iron and vanadium accumulation by North Atlantic ascidians /." Internet access available to MUN users only. Search for this title in:, 2009.

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Lotufo, Tito Monteiro da Cruz. ""Ascidiacea (Chordata: Tunicata) do litoral tropical brasileiro"." Universidade de São Paulo, 2002. http://www.teses.usp.br/teses/disponiveis/41/41133/tde-21052002-125049/.

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Embora tenham sido muito estudadas em diversos pontos do globo, as ascídias do litoral brasileiro são pouco conhecidas. A maior parte do litoral brasileiro está incluída na região tropical, para qual as informações são mais escassas. Com o intuito de se conhecer a fauna de ascídias do litoral tropical brasileiro foram realizadas diversas coletas em diferentes pontos desta região, abrangendo desde a zona entremarés até o infralitoral raso. Outro objetivo do presente trabalho foi o de organizar as informações já existentes a partir de revisão bibliográfica e visitas a algumas instituições que continham coleções representativas. Foram realizadas ao todo 61 coletas em pontos distribuídos entre os estados do Rio de Janeiro, Espírito Santo, Bahia, Alagoas, Pernambuco, Paraíba, Rio Grande do Norte e Ceará. Os animais foram coletados, examinados e identificados até o nível de espécie. Para cada espécie se procurou fazer um extensa revisão taxonômica, tanto a partir da literatura como do exame de tipos depositados em diferentes instituições. O presente trabalho inclui listas sinonímicas, descrições e comentários para cada espécie estudada, com fotografias para a maior parte. Foram adicionadas ainda chaves dicotômicas para todos os táxons, em todas as categorias. Até a realização deste trabalho, 90 espécies de ascídias haviam sido registradas no litoral brasileiro, das quais 54 estão listadas para o estado de São Paulo. Com a realização das campanhas de coletas foram identificadas 67 espécies que, juntamente com uma revisão criteriosa da literatura e o exame de vários tipos e outros exemplares de outras regiões do mundo, fizeram com que a lista atualizada inclua 98 espécies. Estas espécies estão distribuídas entre as 2 ordens e 3 subordens da classe, com um total de 31 gêneros incluídos em 14 dentre as 23 famílias propostas atualmente. Como resultado imediato foram registradas 9 novas ocorrências para o litoral brasileiro, com a descrição de 1 gênero e 10 espécies novas. Além disso, 8 espécies tiveram sua situação alterada por sinonimia ou separação. Juntamente com outros dados da literatura, as tabelas de ocorrências foram submetidas a uma análise de agrupamento e uma análise de endemicidade por parcimônia. As análises evidenciaram um padrão de distribuição semelhante àquele observado para outros grupos bentônicos sésseis, com a divisão da região estudada em duas províncias, a Província Brasileira e a Província Paulista.
Although ascidians are well known in many regions of the globe, information about the group on Brazilian coast are very scanty. Most of the Brazilian coastline is included on the tropical region, which is the poorest known. In order to obtain an inventory of ascidians species on the Brazilian tropical coast, surveys were conducted in different points, ranging from the intertidal to the shallow subtidal depths. Another goal of the present work was to organize all available information through a revision of bibliography and visits to institutions that held representative collections. 61 visits were conducted in places along the coast of the states of Rio de Janeiro, Espírito Santo, Bahia, Alagoas, Pernambuco, Paraíba, Rio Grande do Norte e Ceará. Specimens were collected, examined and identified to the species level. An extensive taxonomic revision was made for every species, by means of literature as well as examination of types and other specimens deposited in different institutions. The present work includes synonymy lists, descriptions, pictures and remarks for each species studied. Keys for all taxa an every category were also included. Up to the present work, 90 species of ascidians had been recorded for Brazil, of which 54 are listed to the State of São Paulo. The surveys revealed a total of 67 species, expanding the list to 98 Brazilian species. Those species are distributed in 2 orders and 3 suborders of the class, with a total of 31 genera included in 14 of the 23 families currently accepted. As an immediate result, were registered 9 new records for Brazilian coast, along with the description of 1 new genus and 10 new species. Furthermore, 8 species have had its taxonomic situation altered by synonymy or separation. The present results, together with data from literature generated tables which were submitted to cluster analysis and a parsimony analysis of endemycity. These analyses revealed a distribution pattern similar to others observed for different benthic taxa. The region studied comprises two provinces, Brazilian Province and Paulista Province.
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8

Davis, Rohan. "Chemical Investigations of Great Barrier Reef Ascidians - Natural Product and Synthetic Studies." Thesis, Griffith University, 2000. http://hdl.handle.net/10072/366561.

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This thesis describes the chemical investigations of several ascidian species collected from the Great Barrier Reef, Queensland, Australia. The thesis is divided into two separate components, Part A focuses on the isolation and structure elucidation of 11 previously undescribed ascidian metabolites. All structures were assigned using a combination of spectroscopic and/or chemical methods. Part B relates to the isolation and chemical conversion of a natural product to a combinatorial template. The natural product template was subsequently used in the generation of a solution-phase combinatorial chemistry library. A further two combinatorial libraries were generated from a synthesised model compound that was related to the natural product template. Part A. Investigation of Aplidium longithorax collected from the Swains Reefs resulted in the isolation of two new para-substituted cyclofarnesylated quinone derived compounds, longithorones J (30) and K (31). The former compound had its absolute stereochemistry determined by the advanced Mosher method. From an Aplidium longithorax collected from Heron Island, two new cyclofarnesylated hydroquinone compounds, longithorols C (46) and D (47) and a novel macrocyclic chromenol, longithorol E (48) were isolated. Longithorol C (46) had its absolute stereochemistry determined by the advanced Mosher method. Chemical investigation of the deep-purple colonial ascidian, Didemnum chartaceum collected from Swains Reefs led to the isolation of five new lamellarin alkaloids, which included the 20-sulfated derivatives of lamellarins B (94), C (95) and L (96), the 8-sulfated derivative of lamellarin G (97) and the non-sulfated compound, lamellarin Z (98). The known lamellarins A (63), B (80), C (64), E (65), G (67), and L (71) plus the triacetate derivatives of lamellarin D (82) and N (83) were also isolated. An aberration in the integration of signals in the 1H NMR spectra of the 20-sulfated derivatives (94-96) led to NMR relaxation studies. T1 values were calculated for all protons in the sulfated lamellarins (94-97) and their corresponding non-sulfated derivatives (80, 64, 71, 67). The protons ortho to the sulfate group in compounds (94-97) had T1 values up to five times larger than the corresponding protons in their non-sulfated derivatives (80, 64, 71, 67). A specimen of Eudistoma anaematum collected from Heron Island was shown to contain a new b-carboline alkaloid, eudistomin V (130), in addition to the two known metabolites, eudistomin H (105) and I (106). Part B. The known natural products, 1,3-diphenethylurea (29), 1,3-dimethylxanthine (30), 1,3-dimethylisoguanine (31) and the salts of tambjamine C (16), E (18) and F (19) were isolated from the ascidian, Sigillina signifera collected in Blue Lagoon, Lizard Island. Base hydrolysis on mixtures of the salts of tambjamine C (16), E (18) and F (19) resulted in the production of 4-methoxy-2,2-bipyrrole-5-carbaldehyde (26). This natural product template (26) was used in the generation of an enamine combinatorial chemistry library (98, 103-111) using solution-phase parallel synthesis. The biaryl compound, 4-(2-thienyl)-1H-pyrrole-2-carbaldehyde (59) was successfully synthesised using Suzuki-Miyaura coupling conditions and subsequently used as a template in the generation of an amine (67, 77, 80-87) and imine (78, 92-95) combinatorial library using solution-phase parallel synthesis.
Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Science
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Salomon, Christine Elizabeth. "The localization of bioactive secondary metabolities in sponges, ascidians and their associated symbionts /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2001. http://wwwlib.umi.com/cr/ucsd/fullcit?p3035432.

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Tincu, John Andrew. "Acid soluble peptides from the hemocytes of the ascidians : characterization and antimicrobial activity /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2003. http://wwwlib.umi.com/cr/ucsd/fullcit?p3118434.

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Books on the topic "Ascidians"

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Sasakura, Yasunori, ed. Transgenic Ascidians. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7545-2.

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Developmental biology of ascidians. Cambridge [England]: Cambridge University Press, 1994.

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Sawada, Hitoshi, Hideyoshi Yokosawa, and Charles C. Lambert, eds. The Biology of Ascidians. Tokyo: Springer Japan, 2001. http://dx.doi.org/10.1007/978-4-431-66982-1.

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Satoh, Noriyuki. Developmental Genomics of Ascidians. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2013. http://dx.doi.org/10.1002/9781118656129.

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Jaffar Ali, H. Abdul, and M. Tamilselvi. Ascidians in Coastal Water. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-29118-5.

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Monniot, Claude. Coral reef ascidians of New Caledonia. Paris: Éditions de l'ORSTOM, Institut français de recherche scientifique pour le développement en coopération, 1991.

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Bullard, Stephan Gregory. A guide to the larval and juvenile stages of common Long Island Sound ascidians and bryozoans. Groton, Conn: Connecticut Dept. of Environmental Protection, 2004.

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Kühne, Stephan. Solitäre Ascidien in der Potter Cove (King George Island, Antarktis): Ihre ökologische Bedeutung und Populationsdynamik = Solitary Ascidians in the Potter Cove (King George Island, Antarctica) : their ecological role and population dynamics. Bremerhaven: Alfred-Wegener-Institut für Polar- und Meeresforschung, 1997.

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Monniot, Claude. Les Ascidies de Polynésie française. Paris: Editions du Muséum, 1987.

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Groepler, Wolfgang. Die Seescheiden von Helgoland: Biologie und Bestimmung der Ascidien. Hohenwarsleben: Westarp Wissenschaften, 2012.

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Book chapters on the topic "Ascidians"

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Pietra, Francesco. "Ascidians." In A Secret World, 164–67. Basel: Birkhäuser Basel, 1990. http://dx.doi.org/10.1007/978-3-0348-7531-8_13.

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Krasovec, Gabriel, Kilian Biasuz, Lisa M. Thomann, and Jean-Philippe Chambon. "Solitary Ascidians." In Handbook of Marine Model Organisms in Experimental Biology, 357–84. Boca Raton: CRC Press, 2021. http://dx.doi.org/10.1201/9781003217503-20.

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Sasakura, Yasunori. "Introduction." In Transgenic Ascidians, 1–3. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7545-2_1.

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Sasakura, Yasunori. "Germline Transgenesis in Ciona." In Transgenic Ascidians, 109–19. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7545-2_10.

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Sasakura, Yasunori. "The Enhancer Trap in Ciona." In Transgenic Ascidians, 121–29. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7545-2_11.

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Yoshida, Keita, and Nicholas Treen. "TALEN-Based Knockout System." In Transgenic Ascidians, 131–39. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7545-2_12.

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Gandhi, Shashank, Florian Razy-Krajka, Lionel Christiaen, and Alberto Stolfi. "CRISPR Knockouts in Ciona Embryos." In Transgenic Ascidians, 141–52. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7545-2_13.

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Cota, Christina D. "Transgenic Techniques for Investigating Cell Biology During Development." In Transgenic Ascidians, 153–64. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7545-2_14.

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Smith, William C. "Cellular Processes of Notochord Formation." In Transgenic Ascidians, 165–77. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7545-2_15.

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Nishino, Atsuo. "Morphology and Physiology of the Ascidian Nervous Systems and the Effectors." In Transgenic Ascidians, 179–96. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-10-7545-2_16.

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Conference papers on the topic "Ascidians"

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Ueki, Tatsuya, and Tri Kustono Adi. "Mechanism of vanadium accumulation and possible function of vanadium in underwater adhesion in ascidians." In INTERNATIONAL CONFERENCE ON BIOLOGY AND APPLIED SCIENCE (ICOBAS). AIP Publishing, 2019. http://dx.doi.org/10.1063/1.5115602.

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Takemoto, K. "Micro XAFS Study on Vanadium in Ascidians Alive Blood Cells Investigated by Fluorescence Scanning X-Ray Microscopy at ID21 at ESRF." In PORTABLE SYNCHROTRON LIGHT SOURCES AND ADVANCED APPLICATIONS: International Symposium on Portable Synchrotron Light Sources and Advanced Applications. AIP, 2004. http://dx.doi.org/10.1063/1.1796585.

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Pavao, Mauro Sergio G., Eliene O. Kozlowski, and Lubor Borsig. "Abstract 2363: Dual effects of unique oversulfated dermatan sulfates from ascidians (Chordata-Tunicata) on tumor invasion: inhibition of ephitelial-mesenchymal transition and hematogeneous metastasis." In Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL. American Association for Cancer Research, 2011. http://dx.doi.org/10.1158/1538-7445.am2011-2363.

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Michelin, Gael, Leo Guignard, Ulla-Maj Fiuza, Patrick Lemaire, Christophe Godine, and Gregoire Malandain. "Cell pairings for ascidian embryo registration." In 2015 IEEE 12th International Symposium on Biomedical Imaging (ISBI 2015). IEEE, 2015. http://dx.doi.org/10.1109/isbi.2015.7163872.

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Sardet, C., C. Rouvière, B. Flannery, and J. Davoust. "Time lapse confocal microscopy of mitochondrial movements in ascidian embryos." In The living cell in four dimensions. AIP, 1991. http://dx.doi.org/10.1063/1.40578.

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Guignard, Léo. "Contact area–dependent cell communications and the morphological invariance of ascidian embryogenesis." In Virtual 12th Light Sheet Fluorescence Microscopy Conference 2020. Royal Microscopical Society, 2020. http://dx.doi.org/10.22443/rms.lsfm2020.10.

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Abdollahian, Golnaz, Michael Veeman, William Smith, and B. S. Manjunath. "A curvicylindrical coordinate system for the visualization and segmentation of the ascidian tail." In 2011 8th IEEE International Symposium on Biomedical Imaging (ISBI 2011). IEEE, 2011. http://dx.doi.org/10.1109/isbi.2011.5872383.

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Chen, Bin, Minglv Sun, Aili Jiang, and Changhai Wang. "Notice of Retraction: Antioxidant Activities of Crude and Fractionated Extracts from the Ascidian Styela clava." In 2011 5th International Conference on Bioinformatics and Biomedical Engineering. IEEE, 2011. http://dx.doi.org/10.1109/icbbe.2011.5780437.

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Putra, M. Y., and F. Karim. "Antibacterial and antioxidant activity-guided isolation studies on Fusarium sp. associated with the ascidian Botryllus schlosseri." In THE 8TH INTERNATIONAL CONFERENCE OF THE INDONESIAN CHEMICAL SOCIETY (ICICS) 2019. AIP Publishing, 2020. http://dx.doi.org/10.1063/5.0001297.

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Sun, Minglv, Bin Chen, Aili Jiang, and Changhai Wang. "Notice of Retraction: Extraction and Antioxidant Activities of Oligosaccharides from Different Parts of the Ascidian Styela Clava." In 2011 5th International Conference on Bioinformatics and Biomedical Engineering. IEEE, 2011. http://dx.doi.org/10.1109/icbbe.2011.5780431.

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Reports on the topic "Ascidians"

1

Kincaid, Erin. Biofouling Management in the Pacific Northwest and Predation on Native versus Non-native Ascidians. Portland State University Library, January 2000. http://dx.doi.org/10.15760/etd.3067.

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