Charles and Gretchen Lambert
home page: http://nsm.fullerton.edu/~lamberts/ascidian/
Number 54 December 2003
There are 118 new publications
listed at the end of this newsletter. This is a longer than usual newsletter
and seemed to be a lot more work for GL than usual; thanks to all of you
who sent contributions, and thanks also for the many letters of support.
We are happy to know that AN seems to be a very useful resource for many
of you; that makes it worth the effort.
During June and July we worked at the Friday Harbor Labs where Gretchen completed a manuscript on the southern hemisphere Corella eumyota that we found in 2 harbors in
found us in
*Ascidian News is not part of the scientific literature and should not be cited as such.
1. From Dr. Hitoshi Sawada,
Sugashima Marine Biological Lab.,
I am organizing "The 4th
International Symposium on the Molecular and Cell Biology of Egg- and
Embryo-Coats", which will be held in Shima,
From Jarrett Byrnes, Population
Biology Graduate Group,
The diversity of ascidians around the world
is truly stunning. Here on the West
Coast of North America, Light's Manual alone lists 46 species without
including several recently introduced species.
As field ecologists, it is important to be able to rapidly identify
species in the field. Taking a cue from
Arjan Gittenberger's www.ascidians.com,
the Stachowicz lab at
With deep sadness we must inform you that
Dr. Sergio de Almeida Rodrigues passed away on October 14th, after a difficult
battle with pneumonia. Dr. Rodrigues (Sergio to his friends and loved ones) was
born in 1937, in
From Hiroki Nishida: I will
be moving to
March. Our lab will continue to study ascidian embryogenesis there and will also start research on larvacean Oikopleura development. The following address will be effective after mid March:
Dept. of Biology, Graduate School of Science,
4. From Gretchen Lambert: Did you know that you can search each issue of AN online using the Find command in the web browser? It is one of the choices in the Edit menu.
More and more websites are being created that are either devoted completely to underwater color photos of ascidians or include ascidians along with other marine invertebrates. Here are a few; if you know of others please contact me and I will include them in the next AN.
Bernard Picton's Encyclopedia of marine life of
developed by Arjan Gittenberger of the Natl. Mus. Of Nat. History in
5. From Teruaki Nishikawa, Nagoya University Museum, Chikusa-ku, Nagoya, Japan (email@example.com): At the Phuket Marine Biological Center (PMBC) in Thailand, the "Internatioal Training Course and Workshop on Environmental Technology related to Taxonomy, Biology and Ecology of Ascidians in Thai Waters" was held 22-28 Nov. 2003. It was organized by PMBC and co-sponsored by PMBC, Southeast Asia START Regional Center (SEA START RC), and National Center for Genetic Engineering and Biotechnology (BIOTEC)), organized by Dr. Somchai Bussarawit (PMBC). As the "resource person", I gave many lectures and practices about ascidian taxonomy, biology and ecology to about 20 participants (including 2 Malaysian MC students, other than Thai students and scientists). Dr. Kanit Suwanarak of Chulalongkorn University gave a lecture on pharmaceutical aspects of ascidian bioreactive substances. For about a week prior to the workshop, I prepared lectures and practices, mainly based on the materials collected from a pearl oyster farm in Phuket. I was astonished to find 18 species of ascidians among the fouling organisms.
6. From Dr. Patricia Kott (Patricia.Mather@qm.qld.gov.au ), to the Tunicata email listserv on June 5 of this year, on the precedence of subphylum Tunicata over Urochordata. (To subscribe, click on the link at the bottom of the AN home page.) We felt it was important to re-run it in AN.
Dear list members,
Quite correctly we are all subscribers to a tunicate list- not a urochordate list. If you are uncertain about this the following notes could help:
The correct name is TUNICATA Lamarck, 1816: The name was used by Lamarck to accommodate the related groups of organisms, ascidians, Pyrosoma and salps. Subsequently Milne Edwards (1843) added the Bryozoa to the Tunicata in the Class Molluscoidea; then Hancock (1850) added Brachiopoda to the Bryozoa and Tunicata in the Molluscoidea; and finally Huxley (1851) recognised the Tunicata (ascidians, salps, doliolids and Appendicularia) as a distinct phylogenetic entity separate from Mollusca, Bryozoa and Brachiopoda. This was later supported by Bronn (1862). Kowalewsky (1866) recognised a chordate affinity in the notochord -like cells in the larval tail and the group Tunicata was regarded as a subphylum of the Chordata.
The name Urochordata was not used until Balfour (1881), quite un-necessarily, created it as a replacement name for Tunicata, presumably to emphasise the chordate affinity. A perfectly good name already existed for a well defined entity and a replacement name was not required. The name Urochordata is a junior synonym of the name Tunicata. The use of the junior synonym for the phylogenetic entity originally established by Lamarck in 1816 is inappropriate. Balfour also unnecessarily introduced the names Perennichordata (for Appendicularia with a tail through life) and Caducichordata (Thaliacea, which occasionally have a tailed larva, and Ascidiacea which always do [with a few molgulid and styelid direct developer exceptions; GL]). There is no justification for the erection of replacement names based on a single character subjectively judged to be of greater significance than others. This practice causes ambiguity and certainly does not lead to the stability in nomenclature that is desirable. The name Tunicata is almost universally used to refer to this group of organisms in the major monographic works on any of its contained Classes, e.g Alder (1863), Herdman ( 1882, 1886 etc.), Alder and Hancock (1905-12), Harant and Vernieres (1933), Brien (1948), Van Name (1945), Berrill (1950), van Soest (1970s-1990s), Fenaux (1993), Bone (1998) and many others.
I hope this helps- see Fenaux(1993) and Brien (1948) for further clarification.
7. From Charles and Gretchen Lambert. Further comments on classification within the Ascidiacea.
The Tunicata includes 4 classes of organisms: Ascidiacea, Sorberacea (considered part of the Ascidiacea by Dr. Patricia Kott), Appendicularia (formerly called Larvacea) and Thaliacea. The first two are sessile and the second two are pelagic as adults, but most have swimming juveniles. Ascidians comprise the most numerous and widely known members of the subphylum or phylum (another issue in classification). In most modern treatments the class is divided into the orders Enterogona and Pleurogona with the suborders Aplouosobranchia and Phlebobranchia in the Enterogona and a single suborder, the Stolidobranchia in the Pleurogona (Abbott et al. 1997, Kott 1985). Originally the suborders were designated as the orders Aplousobranchia, Phlebobranchia and Stolidobranchia (Lahille 1886). This was based upon the complexity of the branchial sac. Subsequently, Perrier (1898) devised the orders Enterogona and Pleurogona based upon the position of the gonads and other morphological considerations. Garstang (1928) and others such as Huus (1937) combined the classification of Lahille and Perrier incorporating Lahille’s Aplousobranchia and Phlebobranchia as suborders of the Enterogona with the Pleurogona containing only the suborder Stolidobranchia (Berrill, 1950). However, this classification has not been universally accepted. Van Name (1945) retained the 3 orders of Lahille in his monumental treatise as did the Monniots in their 1991 book Coral Reef Ascidians of New Caledonia (which remains the most comprehensive account of all aspects of ascidian biology that we know of). In addition, Lahille’s 3 orders are listed as current designations in a recent textbook of invertebrate zoology (Ruppert and Barnes, 1994).
Thus, it is clear that the terminology of Lahille has precedence over that of Perrier and several prominent ascidiologists have recognized this. Moreover, uniting the suborders Aplousobranchia and Phlebobranchia into the order Enterogona implies an evolutionary relationship that may or may not be supported. Therefore we prefer Lahille’s 3 orders and advocate that this classification should be adhered to in all future accounts of the ascidians. We also commend Dr. Kott for her succinct review of the precedence of using subphylum Tunicata over Urochordata.
D. P., Newberry, A. T., and Morris, K. M. (1997). Reef and Shore Fauna of
Berrill, N. J. (1950). The
Tunicata with an Account of the British Species. The Ray Society,
Garstang, W. (1928) The morphology of the Tunicata, and its bearings on the phylogeny of the Chordata. Quart. Jour. Micr. Sci., 72: 51-187.
Huus, J. (1937) Tunicata: Ascidiaceae. Handb. Zool. Kukenthal und Krumbach, V, second half, pp543-672.
Kott, P. (1985). The
Australian Ascidiacea part 1, Phlebobranchia and Stolidobranchia. Mem.
Lahille, F. (1886). Sur la classification des tuniciers. CR Acad Sci Paris 102: 446-448.
Monniot, C., Monniot, F.
and Laboute, P. (1991). Coral Reef Ascidians of
Perrier, J.O.E. (1898) Note sur la classification des
Tuniciers. C.R. Acad.Sci.
Ruppert,E.E, Barnes, R.D. (1994) Invertebrate Zoology
Van Name, W. G. (1945). The North and South American Ascidians. Bull. Amer. Mus. Nat. Hist. 84: 1-476.
WORK IN PROGRESS
Carman, Geology & Geophysics, Woods Hole Oceanog. Inst., Woods
Frank, A. DeTomaso, B. Hedman and K. O. Hodgson: "Perophora surprise: a new structural motif
for biological iron." Dept. of Chemistry; Hopkins Marine Station; and The
Stanford Synchrotron Radiation Laboratory, SLAC;
At the 30th Annual Users' Meeting at SSRL in October 2002, we reported the preliminary results of our x-ray absorption study of iron in Perophora annectens, whole blood and whole body (noted in AN 52). We have now looked at 2 independent collections, and the iron is of a constant type and in very high abundance. Vanadium is in very low amounts. The iron looks to be an iron-oxo complex containing more than 2 iron atoms per unit and does not look like the biological iron in ferritin. The structure is similar in many respects to the Fe4O4 cube found in the mineral magnetite but with clear structural differences that show up in the x-ray spectra. This is a brand new motif for biological iron. In the near future, we intend to report the full details of the proposed new structure coming from EXAFS analysis. What is most clear is that blood cell iron in P. annectens is not Fe+2 or Fe+3 floating as the aqua ion in acid solution, as one finds for V+3 in many ascidians. We do not know whether the iron in P. annectens is similar to biological iron in other iron-containing ascidians, or is unique to the species.
3. Charles Lambert: Enzymatic removal of the ascidian egg vitelline coat at low pH. Previous methods of enzymatic removal of the VC involved S-S reduction at high pH along with a proteolytic enzyme (Mita-Miyazawa, Ikegami and Satoh, 1985, J. Embryol. Exp. Morphol.87: 1-12; Byrd and Lambert 2000. Molecular Repro. and Dev. 55: 109-116). For work on GVBD I needed VC-free oocytes that had never been exposed to pHs above 4. Tris(2 carboxyethyl)phosphine hydrochloride (TCEP) is reported to reduce S-S bonds irrespective of pH. To 10 ml of Boltenia villosa oocytes in pH 4 SW (10mM citrate) add 143 mg TCEP (Molecular Probes T-2556) and 10 mg pepsin (Sigma). Incubate with shaking for 1 hour at 10-120C. and wash several times with pH 4 SW. Most of the oocytes will be VC free.
4. From Christian Sardet, Station Zoologique,
Villefranche-sur-Mer, France (firstname.lastname@example.org
) : We had a great meeting in Carry le
Rouet near marseille organized by the Lemaire team where we felt the ascidian
developmental biology community was really taking off. Villefranche
had 8 abstracts at the Marseille meeting.
We have now 3 new Research Staff in Villefranche all recruited by the
CNRS and starting labs: Alex Mc Dougall (signalisation/ calcium/cell
cycle control) and Hitoyoshi Yasuo (notochord formation) working with Clare
Hudson (neural development). See o
Another project (in French for the moment) is our effort to present the history, patrimony and science of Villefranche on a site for the public (http://www.darse.org). Jean and Colette Febvre who are now retired are very active in this context. Finally on a personnal level I am busy finishing my term as president of the French Cell Biology Society and organizing the next big Meeting in Nice (World Congress of Cell Biology: 25000 people expected) with a new and very dynamic European Society called ELSO (This will be an exciting international meeting. See http://www.elso.org)
1. International Urochordate Meeting 2003, Carry le Rouet, France, October 11 - 15th
Organized by Patrick Lemaire, Marseille (France)
Opening lecture: Let's move on ascidian biology with new ideas. Nori Satoh, Dept. of Zool.,
Session 1.1: From fossil evidence to molecular phylogeny
Session 1.2: Evolution of developmental patterns
Session 2: Characteristics of the tunicate genomes
Session 3: Functional analysis of the ascidian genomes: Tools and approches
Session 4: Early embryonic patterning
Session 5.1: Neural development and chordate evolution
Session 5.2: Neural function
Session 6.1: Oogenesis, fertilization and early development
Session 6.2: Metamorphosis and immunity
Click on link to see the complete list of speakers (with addresses, most with email), abstracts, and posters: http://nsm.fullerton.edu/~lamberts/ascidian/UromeetingAbstracts.html
2. 9th Intl. Congress of the Intl. Soc. for Dev. and Comp. Immunology, Univ. of St. Andrews, Scotland, UK 29th June - 4th July 2003
a) Immunotoxicity of Cu(I) and Irgarol 1051 in ascidians. F. Cima, P. Burighel, L. Ballarin, Dept. of Biol.,
After the widespread ban of TBT due lo a severe impact to coastal biocenoses mainly related to its immunosuppressive effects on both invertebrate and vertebrates, alternative biocides like Cu(t) salts and the triazine Irgarol 1051 (previously used in agriculture as a herbicide) have been massively introduced in combined formulations of antifouling paints against a wide spectrum of fouling organisms. Our interest in the study of ascidian defence reactions led us to investigate the effects of Cu(l) and Irgarol on cultured phagocytes of the colonial ascidian Botryllus schlosseri, as previously done with TBT. We set up short-term haemocyte cultures (60 mìn) exposed to sublethal concentrations of these compounds (Cu(l) LC50 =281 µM; Irgarol LC50 > 500 µM). In contrast to TBT, both substances did not cause significant effects on cell morphology. Generally, Cu(I) appeared more toxic than Irgarol; it significantly inhibited(p < 0.05) yeast phagocytosis at 0.1 µM, and affected calcium homeostasis and the mìtochondrial cytochrome-c-oxidase activity at 0.01 µM. Both substances were able to change membrane permeability, induce apoptosis from concentrations of 0.1 µM and 200 µM for Cu(I) and Irgarol, respectively, and alter (with different mechanisms) the activity of hydrolases (acid phosphatase, esterases) and oxidases (phenoloxidase). Although both the xenobiotics are less toxic tram TBT and their LC50 values are lower than the concentrations in the aquatic environment, their impact on organisms must be considered as they can alter immune defences and consequently endanger the survival of the individual.
b) Morula cell behaviour in the rejection reaction
between incompatible colonies of the ascidian Botryllus schlosseri. L. Ballarin and F. Cima, Dept. of Biol.,
Contact between genetically incompatible colonies of the ascidian Botryllus schlosseri result in a rejection reaction that is characterised by the appearance of a series of dark-brown necrotic spots along the touching borders of the facing vascular ampullae. Morula cells (MC), a common haemocyte-type in botryllid ascidians, are directly involved in this reaction as they contain and release the enzyme phenoloxidase which is responsible for the observed cytotoxicity. Since MC are known to undergo in vitro degranulation upon the recognition of incompatible blood plasma, we re-investigated the whole rejection process with particular reference to the behaviour of MC. MC were observed to crowd inside the ampullar tips in early stages of the rejection: their vacuoles share an equal size and an uniformly electron dense contents, which are yellow green in colour after aldehyde fixation and positive for phenoloxidase. As their migration into the common tunic begins, their vacuolar contents progressively flake off and are finally released into the ampullar lumen or in the tunic as the MC degranulate. Most of the degranulated MC are still observable inside the ampullae in advanced stages of the rejection process. Just before the beginning of degranulation, MC acquire immunopositivity lo anti-lL-1-a and anti-TNF-a, thus confirming their important immunomodulatory rote. In vitro experiments demonstrate that the synthesis of cytokine-like molecules is consequent to the recognition of humoral factors from incompatible, allogeneic blood plasma and is followed by an increase of nitrite concentration in the incubation medium.
c) External amoebocytes
perform immunosurveillance of the pharynx entry in ascidians (Urochordata). P. Burighel, L. Ballarin, F. Gasparini, F.
Caicci, F. Cima, Dip. Biol., Univ.
In vertebrates, the mouth and gills are the principal targets of pathogen invasion and these are protected by motile, phagocytic and cytotoxic cells of the local lymphatic tissues. The body or lower chordate ascidians is covered by the tunic, which extends over the epidermis and into both the siphons. In botryllids, the tunic contains various cell types. particularly granular amoebocytes coming from blood, and forms a superficial cuticle bearing numerous papillae protrusions, An unusual feature that we observed was the presence of granular amoebocytes, over the tunic into both the siphons of Botryllus schlosseri, completely exposed to seawater These free amoebocytes in the oral siphon were especially accumulated at the base of the tentacles, and were in contact with the cuticle protrusions and their long filopodia. Electron microscopy revealed that the amoebocytes appear mononucleate and with numerous round granules, varying in content. We consider these cell represent “sentinel-cells” belonging to the phagocytic line of the immune system since they share with blood phagocytes the same hydrolytic enzyme pattern, and labelling by both n-mannose specific lectin and anti-CD39 antibody produced against mammalian macrophages. After exposing the filtering colonies lo bacterial spores the external amoebocytes were observed to contain bacteria inside heterophagic vacuoles, starting after 5 min exposure to the spores. Moreover, these cells seem to participate in cell signalling since they cross the siphonal epidermis triggering a cascade of events leading to morula cell degranulation inside the siphonal blood sinus and the progressive increase of circulating, bacteria-containing macrophages, which were finally discharged into the peribranchial chamber.
d) Complement mediated chemotaxis in the deuterostome invertebrate Ciona intestinalis. Maria Rosaria Pinto1, Cinzia M. Chinnici3, Yuko Kimura2, Rita Marino1, Daniela Melillo1, Rosaria De Santis1, Nicolò Parrinello3, John D. Lambris2 1Cell Biol. Lab., Stazione Zool. “A. Dohrn”, Napoli, Italy; 2Protein Chemistry Lab., Univ. of Pennsylvania, U.S.A.; 3Dept. of Animal Biol., Univ. of Palermo, Italy
Some deuterostome invertebrates posses complement-like genes and in limited instances, complement mediated functions have been reported for invertebrate species. However, the organization of complement pathway(s) as well as the functions exerted by the cloned gene products is largely unknown. There is no evidence of the inflammatory and lytic pathways, which are key effector mechanisms of the mammalian complement cascade. To address this issue, we have initiated studies to characterize the structure and functions of Ciona intestinalis complement components and receptors. In a recent study, we have cloned two C3-like genes, CiC3-1 and CiC3-2, from C. intestinalis. Here we expressed the fragment of C3-1a (rCiC3-1a) that corresponds to mammalian C3a and assessed its chemotactic activity using C. intestinalis blood cells. The CiC3-1a was expressed in E. coli, purified using nickel chelating affinity chromatography and HPLC, and its identity verified by mass spectrometry. Migration of C. intestinalis coelomocytes towards rCiC3-1a was dose-dependent, peaking at 500 nM and was specific for rCiC3-1a as it was inhibited by an anti-rCiC3-1a specific antibody. Similarly to the mammalian C3a, the chemotactic activity of C. intestinalis C3-1a is localized at the C-terminus of the C3a molecule as a peptide representing the 18 C-terminus amino acids (CiC3-1a59-77). Ci-C3a promotes, similarly to the expressed molecule, coelomocyte chemotaxis. The C3a mediated chemotaxis was inhibited by pre-treatment of cells with pertussis toxin thus suggesting that the receptor molecule mediating the chemotactic effect is Gi protein-coupled. The possible role of complement in C. intestinalis inflammatory processes will be discussed.
e) Inflammation in ascidians. N. Parrinello, C. Chinnici, A. Vizzini, M. Cammarata, Dept. of Animal Biol., Univ. of Palermo, Italy.
Inflammatory responses in solitary ascidians include cell migration, phagocytosis, encapsulation of larger particles, tissue injury, and wound repair. In encapsulation responses in the tunic of Ciona intestinalis, an increased expression of type IV-like collagen and elastin-like molecules have been found, apparently produced by the epidermis. Inflammatory cells have been identified as amoebocytes, univacuolar cells, unigranular refringent cells (URG) and morula cells. We show the involvement of a large amount of URGs following LPS injections. These cells contain polyphenols and, in vitro, showed a phenoloxidase-dependent cytotoxic activity. Probably, URGs migrate through the epithelium from tissue lining the lacunae under the tunic. Chemotactic stimuli, that induce migration into the inflamed area, could be due to a C3-like molecule while an immunohistochemical study shows that molecules containing interleukin-1-like epitopes are expressed (2-4 hours) by endothelial tissue lining the pharyngeal wall. An IL-1-like functional activity may be indicated by the increased number in the lacunae as a result of the cell proliferation response. Accordingly, we found IL-1-receptor epitopes in cell nodules of the pharyngeal bars ansae. The recently elucidated genome of Ciona intestinalis did not reveal IL-1-like genes whereas an IL-1-receptor was found. However, human IL-1 traits can be observed by examining the Ciona genome sequence. Finally, the expression of a phenoloxidase component could be stimulated by inflammatory stimuli. Inflammation in ascidians presents invertebrate and vertebrate characteristics.
3. IBMANT-ANDEEP (Interactions between the
Magellan Region & the Antarctic-Antarctic Benthic Deep-sea Bioiversity)
Intl. Symposium & Workshop 20-24 October 2003
differentiation between populations of the ascidian Aplidium falklandicum
The genetic structure of populations of sessile marine animals depends largely on the dispersal abilities of the larval stages. It is expected that species with higher dispersal capabilities will present less genetic structure than those with larvae that disperse only relative short distances, which in turn would present small scale genetic differentiation. Among the factors that could affect the dispersion of the free-living stages, and therefore the gene flow between populations are the variable spawning and recruitment success, habitat availability, oceanographic conditions and physical barriers.
The Polar Front and the
abissal depths that surround
Primary production pulses and temperature have been signed among the most important factors in determine reproduction traits, especially in benthic fauna. Although temperature changes are slight year-round it has been argued that due to the evolutionary history of Antarctic organisms even such variations are detectable and could regulate reproductive cycles. On the other hand, the strong seasonal nature of energy input to the system has also been signed as the driving force behind all seasonal processes in the Southern Ocean, particularly important in organisms situates in the first levels of the food chain. It has also been suggested that different development strategies would determine reproductive cycles in benthic organisms. Thus, reproduction in animals with planktotrophic larvae should be coupled to primary production pulses, while those with lecithotrophic larvae or direct development should be released from those pulses and can reproduce aseasonally. Ascidians are common members of the Antarctic benthic communities and reproduce via a lecithotrophic larvae. This study intends to answer the question whether reproduction of ascidians at Potter Cove is continuous, as to be expected from the lecithotrophic nature of ascidian larvae and/or the low annual temperature amplitude, or whether it is limited to the summer, as to be expected from the distinct seasonality in primary production. Five ascidian species, Ascidia challengeri, Cnemidocarpa verrucosa, Corella eumyota, Molgula pedunculata and Pyura setosa were sampled at Potter Cove over a ca 15 months period during 1996/1997. The reproductive cycles were examined by histological analysis of the gonads. Temperature and chlorophyll-a data were obtained in the water column between 20 and 30 m depth from a long term monitoring programme running at Potter Cove. Reproduction of these suspension feeders seems to be decoupled from the pulses of primary production characteristic of Antarctic systems, except for P. setosa which showed their reproductive peaks coincident with chlorophyll-a pulses. While none of the reproductive cycles studied were related to temperature changes. Although reproduction in A. challengeri and C. eumyota did not show a significant relation to chlorophyll-a levels the vitellogenesis in these species took place during the austral summer. Different were the case of C. verrucosa and M. pedunculata which reproduced during the austral winter and showed a marked vitellogenic period previous to spawning. These results were striking and somehow unexpected, in first term because these are phylogenetically very close organisms and are living under the same environmental pressures. And in second term because, at least at first sight, to reproduce during the Antarctic winter could appears as energetically disadvantageous especially for filter feeders. However, C. verrucosa and M. pedunculata are two of the dominant species of macrobenthic communities at Potter Cove. Whether these reproduction strategies are phyllogenetically fixed or are local ecological adaptations is still an open question. Energetic implications of these cycles as well as their possible relation to small-scale distribution patterns are discussed.
c) Report on the trophic ecology of the macrophagous ascidian Cibacapsa gulosa Monniot & Monniot, 1983. Lescano M. N. 1, Tatián M. 1, Sahade R. 1 & Fuentes V.L. 2 1Ecología Marina, FCEFyNat, UNC-CONICET. email@example.com 2 Dept. de Ciencias Biológicas, FCEyN, UBA-CONICET.
To know the trophic ecology of the macrophagous ascidian Cibacapsa gulosa Monniot & Monniot, 1983 (Ascidiacea, Octacnemidae), microscopical analyses were performed both, on stomach contents and on the wall of the postpharyngeal digestive tract. Octacnemids represent a different pathway in the evolution of the typical suspension-feeding strategy in ascidians. A total of three specimens were collected during the LAMPOS cruise in the area of the South Sandwich Islands at depth of 590 m. Specimens were immediately fixed in buffered formaldehyde 2.5% in sea water. The different prey items found in the gut contents were identified and counted under stereo-microscope using a Bogorov 10 ml counting chamber. Microscopical observations were also performed on different sections of the gut (oesophagus, stomach and intestine). The macrophagia in Cibacapsa gulosa was confirmed, but it is more diversified than previously supposed. Gut contents were constituted by harpacticoid and calanoid copepods, lumbrineriform polychaetes, halacarids, eusirid and gamaroid amphipods, ophiuroids, jelly-fishes, gastropods, crustacean parts and fish scams. All these items had a wide range size: from 100 µm in the case of small calanoid copepods up to 8 mm of some polychaetes. High quantities of orange lipid drops, were also observed in the contents. The wall of the post-pharyngeal digestive tract was lined by cylindrical mono-stratified epithelium, which reposes on a wide mesenchyme with blood sinus and extra-vascular blood cells. The external epithelium along the whole post-pharyngeal digestive tract was mainly formed by cubic cells. At the level of the oesophagus, the inner epithelium was ciliated and showed an intense basophilia in the apical region. Ciliated mucous cell was the main cell type identified; zymogenic cells were also scattered along the epithelium. Several cell types were observed in the gastric wall: ciliated mucous cells (with large supra-nuclear vacuoles); zymogenic cells; undifferentiated cells and concretion cells, these only identified previously in the class Sorberacea (Gaill, 1979). The most abundant cell type present in the intestinal epithelium was the ciliated mucous cell; other two cell types present in this region were zymogenic and undifferentiated cells. Capture of this wide variety of preys (some of these having a great mobility) by C. gulosa, suppose a special behaviour in this sessile species. Although prey items have a benthic and pelagic origin, the presence of components from the zooplankton could explain the high quantities of oil drops found in the contents: lipid storage as been stressed in amphipods and copepods living in polar regions, reaching the lipids an important percentage of its dry weight during the year-round. The presence of zymogenic cells in the whole post-pharyngeal digestive tract indicates that an intense enzyme secretion should be necessary to digest this diet, composed by organisms provided with hard parts. Intracellular concretions were not observed previously in other ascidians. Their presence in Sorberacea and in C. gulosa may be explained by homology or, by an independent acquisition in both groups (adaptation to the macrophagia). This special feeding ecology (based in the capture of a very energetic, but probably occasional preys) should be a successful strategy, regarding the scarcity of particles (i.e., products derived from the primary production) that reach this benthic ambient.
(Tunicata, Ascidiacea): biogeography along the
In Southern Ocean, the Polar Front determines, as in many organisms, strong barriers for the ascidian distribution. The Northern Magellan and Southern Antarctic regions separated by this barrier, could be linked by the Scotia Arc, as was pointed out by Monniot & Monniot (1983) who found a faunal gradient between these regions through the Scotia Arc. The knowledge on the species composition in these areas is, nevertheless, fragmentary. During the LAMPOS cruise (ANT XIX/5, RV “Polarstern” April-May 2002), ascidians were collected on different stations along the Scotia Arc. Our objectives are to extend the knowledge on species composition and to establish affinities between the ascidian fauna at the different stations performed during the cruise, analyzing the influence of the Polar Front on the ascidian distribution. Material was collected by Agassiz (AGT) and bottom (GSN) trawls, at depths between 250-600 m, on different substrate types. Animals were relaxed in current seawater and later fixed in buffered formalin seawater 4%. Morphological features were analyzed under binocular and microscope, to identify the different species. The reproductive status of colonial species was taken in account, recording the presence of tadpoles. Photographs were taken on living animals using a digital camera, to document the coloration, which is usually lost after fixation. Affinities between the different stations/localities were performed using cluster analysis (Bray-Curtis similarity, UPGMA) and ordination (multidimensional scaling, MDS). Analyses were also performed pooling previous data on ascidian distribution (Monniot & Monniot, 1983) and the present results.
A total of 25 species were found along the different stations sampled during the cruise, being solitary species slightly more abundant. Two species are new for the science, whereas 7 species were collected in new localities, extending their known area of distribution. Ascidians were present in more than 80% of the captures. Muddy bottoms supported higher species richness than hard bottoms, like gravel, pebbles and volcanic stones.
Annual Meeting of the Zoological Society of
a) Analysis of metal-related genes in the vanadium-rich ascidian, Ascidia sydneiensis samea
N. Yamaguchi, K.
Kamino, T. Ueki, T. Uyama and H. Michibata.
Marine Biological Laboratory, Graduate School of Science,
Several ascidian species are known to accumulate high levels of vanadium in their vanadocytes. The highest level observed in Ascidia gemmata corresponds to about 107 times the levels in seawater. To investigate the phenomenon, we carried out an expressed sequence tag analysis (EST) of blood cells of A. sydneiensis samea, in which 13 mM vanadium is accumulated. We obtained randomly selected 1,300 ESTs from the vandocytes and whole blood cells cDNA libraries. In this study, 62 metal-related genes were identified. In particular, ferritin H-subunit, which is known as an iron storage protein, and novel vanabins were found. Vanabins have been extracted from A. sydneiensis samea blood cells, cloned and identified as low molecular weight vanadium-binding proteins. Vanadium binding ability of these proteins was confirmed by immobilized metal affinity chromatography and gel filtration column chromatography.
b) Analysis of metal binding activity of vanadium-binding proteins (vanabins) from an ascidian Ascidia sydneiensis samea. T. Ueki, K. Fukui and H. Michibata
We have previously identified several vanadium-binding proteins (vanabins) expressed abundantly in the cytoplasm of vanadium-accumulating cells, vanadocytes, of a vanadium-rich ascidian Ascidia sydneiensis samea. We have cloned cDNAs for the two vanabins, vanabin1 and vanabin2, and examined their metal binding ability using recombinant proteins. Vanabin1 and vanabin2 can bind 10 or 20 vanadium ions, respectively, at +4 oxidation state (VO2+) at a dissociation constant of around 2 X 10-5 M. In this study, we found that by an EPR study the coordination environment of vanabin2 against VO2+ ions is N2O2 type, and amino residue of lysines contribute to the coordination. In addition, by a metal-chelating column method, we found that vanabins can bind to copper (II) and iron (III) ions.
c) Cloning of cDNAs for sulfate transporters in the vanadocytes of Ascidia sydneiensis samea. H. Kawamichi, N. Yamaguchi, T. Ueki and H. Michibata.
A considerable amount of sulfate is always found in association with vanadium in ascidian blood cells. It is suggested that sulfate might be involved in the biological function and/or the accumulation and reduction of vanadium. In the case of Ascidia gemmata, 350 mM vanadium and 500mM sulfate ions were contained in vacuoles of vanadocytes, thus, the content ratio of sulfate to vanadium was estimated to be approximately 1.5, as would be predicted if sulfate ions are present as the counter ions of vanadium(III). As the first step towards an analysis of the possible correlation of vanadium and sulfate, we did plan to isolate the sulfate transporter gene and analyze its function. Since STAS sequence are conserved in the C-terminal of sulfate transporters, we aligned the amino acid sequences of sulfate transporter genes derived from Genebank, with those of putative Ciona sulfate transporter derived from EST project database. Based on the alignment, we have constructed some degenerate primers and amplified cDNAs by PCR from cDNA library of blood cells of Ascidia sydneiensis samea.
International Marine Biotechnology Conference
a) Vanadium-binding proteins (vanabins) of an ascidian Ascidia sydneiensis samea. T. Ueki, Y. Sakamoto, T. Watanabe and H. Michibata
Ascidians, tunicates or sea squirts, are well known to accumulate high levels of vanadium ion in the vacuole of one or more type(s) of blood cells. We previously identified several low molecular weight vanadium-binding proteins, designated vanabins, from the cytoplasm fraction of vanadium-containing cells or from the coelomic fluid. We have cloned cDNAs for vanabin1 (12.5 kDa) and vanabin2 (15 kDa) from cytoplasmic fraction and vanabin-P from the ceolomic fluid. We examined the activities of the recombinant vanabins to bind metal ions including vanadium (IV) and vanadium (V) by Hummel-Dreyer's method. Recombinant proteins of the two vanabins, vanabin1 and vanabin2, bound to 10 and 20 vanadium(IV) ions with dissociation constants of 2.1 x 10-5 M and 2.3 x 10-5 M, respectively. The binding of vanadium(IV) to these vanabins was inhibited by the addition of copper(II) ions, but not by magnesium(II) or molybdate(V) ions. Vanabin2 also bound to 5 copper (II) ions, but not to iron (III) ions. By expressing fusion proteins of vanabins in E. coli, the cells obtained ability for copper accumulation but not for vanadium. Vanabins are the first proteins reported to show specific binding to vanadium ions; this should provide a clue to resolving the problem regarding the selective accumulation of vanadium in ascidians.
b) Novel vanadium-binding protein (vanabin) from cDNA library of the ascidian, Ciona intestinalis. Subrata Trivedi, Nobuo Yamaguchi, Tatsuya Ueki, and Hitoshi Michibata
Some ascidians, particularly those belonging to the suborder Phlebobranchia are known to accumulate high levels of vanadium. Vanadium binding proteins (Vanabins) were first isolated from the vanadium-rich ascidian, Ascidia sydneiensis samea. Data base search revealed five groups of vanabin-like genes in another ascidian Ciona intestinalis. Here we report the cDNA and genome sequence analysis of Ciona vanabins. The predicted amino acid sequences of the five groups of vanabins were highly conserved and related to Ascidia vanabins. The genes encoding each of Ciona vanabins were clustered in 8.4-kb genomic region. We also report the functional assay of one group of the Ciona vanabins (Group 0). The recombinant protein was produced in E. coli, and vanadium binding experiment was done using metal-chelating column chromatography (batch method). The Group 0 vanabin bound to the vanadium (IV) ions immobilized on the resin, and was eluted by elution buffer containing different concentrations of NaCl. This is the first vanadium binding protein to be reported other than those found in Ascidia sydneiensis samea.
c) Marine biotechnological approaches to the accumulation of metals by ascidians. Hitoshi Michibata, Tatsuya Ueki, Nobuo Yamaguchi and Hozumi Kawamichi
90 years ago, Henze discovered high levels of vanadium in the blood (coelomic)
cells of an ascidian collected from the
The role of integrins in Ascidia ceratodes sperm activation and fertilization. Janice Soratorio, Master’s thesis, Calif. State Univ. Fullerton Dept. of Biol. Sci. Advisor Dr. Robert A. Koch.
Mitochondrial translocation is an early event during ascidian fertilization in which the sperm mitochondrion binds to the outer surface of the egg complex, undergoes a morphological change and translocates from the head of the sperm down to the tail. This process is dependent on actin cytoskeletal reorganization and driven by myosin. Due to integrin’s known association with actin filaments, we hypothesize that integrins mediate adhesion of the sperm cell to the outer surface of the egg and signal the formation of focal adhesion-like complexes. Thus, we predict that one or more integrin family members will span the membrane and interact with focal adhesion-like complex-specific proteins in the cytosol, e.g., talin, paxillin and FAK. Using anti-integrin aHr1 and bHr prepared against the ascidian Halocynthia roretzi protein and anti-integrin b1, integrins were detected on the mitochondrial region of ascidian sperm heads. Integrin b2, b3 and b4 were not detected in the sperm. The head also labeled positively for the cytoskeletal proteins, talin, paxillin and FAK, a tyrosine kinase that is known to associate with integrins in focal adhesion sites. It is known that focal adhesion complex formation depends on integrin receptor occupancy and clustering. To study these, sperm were exposed to an anti-integrin antibody known to induce integrin clustering, mAb 12G10, and an antibody known to have no effect on integrin activation and clustering, K20. We found that mAb 12G10 triggered sperm activation in a manner similar to positive controls. K20 also activated the sperm with less response. LY294002, a PI3 kinase inhibitor, was used to determine if integrin clustering is involved in the signaling cascade during MTL. When sperm was pretreated with the inhibitor then exposed to the clustering antibody, induced activation by mAb12G10 was blocked. To determine integrin’s function during fertilization, dose-dependent inhibition by echistatin and anti-bHr was tested. In the presence of echistatin (1.5 and 15 µM), fertilization was inhibited and decreased to 60% and 47%, respectively. Similar results were observed in the presence of anti-bHr, with more inhibition with higher concentration from 50% to 30%. These data demonstrate: (1) the presence of integrins on the ascidian sperm cell surface, (2) the presence of protein characteristic of focal complexes, (3) integrin clustering, found upstream of PI3 kinase, is not necessary for MTL, and (4) suggest the importance of integrins as sperm-surface egg receptors in ascidian fertilization.
Aassila, H., Bourguet-Kondracki, M. L., Rifai, S., Fassouane, A. and Guyot, M. 2003. Identification of harman as the antibiotic compound produced by a tunicate-associated bacterium. Mar. Biotechnol. 5: 163-166.
Aassila, H., Bourguet-Kondracki, M. L., Rifai, S., Fassouane, A. and Guyot, M. 2003. Identification of harman as the antibiotic compound produced by a tunicate-associated bacterium. Mar. Biotechnol. 5: 163-166.
Abourriche, A., Abboud, Y., Maoufoud, S., Mohou, H., Seffaj, T., Charrouf, M., Chaib, N., Bennamara, A., Bontemps, N. and Francisco, C. 2003. Cynthichlorine: a bioactive alkaloid from the tunicate Cynthia savignyi. Farmaco 58: 13511354.
Addadi, L., Raz, S. and Weiner, S. 2003. Taking advantage of disorder: amorphous calcium carbonate and its roles in biomineralization. Adv. Mat. 15: 959-970.
Aiello, A., Esposito, G., Fattorusso, E., Iuvone, T., Luciano, P. and Menna, M. 2003. Aplidiasterols A and B, two new cytotoxic 9,11-secosterols from the Mediterranean ascidian Aplidium conicum. Steroids 68: 719-723.
Akanuma, T. and Nishida, H. 2003. Ets-mediated brain induction in embryos of the ascidian Halocynthia roretzi. Dev. Genes & Evol. .
Albalat, R., Permanyera, J., Cañestro, C., Martínez-Mira, A., Gonzàlez-Anguloa, O. and Gonzàlez-Duarte, R. 2003. The first non-LTR retrotransposon characterised in the cephalochordate amphioxus, BfCR1, shows similarities to CR1-like elements. Cell. & Mol. Life Sci. 60: 803–809.
Azumi, K., Takahashi, H., Miki, Y., Fujie, M., Usami, T., Ishikawa, H., Kitayama, A., Satou, Y., Ueno, N. and Satoh, N. 2003. Construction of a cDNA microarray derived from the ascidian Ciona intestinalis. Zool. Sci. 20: 1223-1229.
Beiras, R., Bellas, J., Fernandez, N., Lorenzo, J. I.
and Cobelo-Garcia, A. 2003. Assessment of coastal marine pollution in
Beiras, R., Fernandez, N., Bellas, J., Besada, V., Gonzalez-Quijano, A. and Nunes, T. 2003. Integrative assessment of marine pollution in Galician estuaries using sediment chemistry, mussel bioaccumulation, and embryo-larval toxicity bioassays. Chemosphere 52: 1209-1224.
Bellas, J., Beiras, R. and Vazquez, E. 2003. A standardisation of Ciona intestinalis (Chordata, Ascidiacea) embryo-larval bioassay for ecotoxicological studies. Water Res. 37: 4613-4622.
Bertrand, V., Hudson, C., Caillol, D., Popovici, C. and Lemaire, P. 2003. Neural tissue in ascidian embryos is induced by FGF9/16/20 acting via maternal GATA and ETS factors. November 28:
Bibby, T. S., Nield, J., Chen, M., Larkum, A. W. and Barber, J. 2003. Structure of a photosystem II supercomplex isolated from Prochloron didemni retaining its chlorophyll a/b light-harvesting system. Proc. Nat. Acad. Sci. 100: 9050-9054.
Bishop, C. D. and Brandhorst, B. P. 2003. On nitric oxide signaling, metamorphosis, and the evolution of biphasic life cycles. Evol. & Dev. 5: 542-550.
Bone, Q., Carre, C. and Chang, P. 2003. Tunicate
feeding filters. J. Mar. Biol. Ass.
Brena, C., Cima, F. and Burighel, P. 2003. The highly specialised gut of Fritillariidae (Appendicularia: Tunicata). Mar. Biol. 143: 57-71.
Bruce, A. J. 2003. A new species of Dactylonia
fransen (Crustacea : Decapoda : Pontoniinae) from
Burighel, P., Lane, N. J., Fabio, G., Stefano, T., Zaniolo, G., Carnevali, M. D. and Manni, L. 2003. Novel, secondary sensory cell organ in ascidians: in search of the ancestor of the vertebrate lateral line. J. Comp. Neurobiol. 461: 236-249.
Cañestro, C., Albalat, R. and Gonzàlez-Duarte, R. 2003. Isolation and characterization of the first non-autonomous transposable element in amphioxus, ATE-1. Gene 318: 69-73.
Carman, M. R. and Roscoe, L. S. 2003. The didemnid
Carroll, M., Levasseur, M., Wood, C., Whitaker, M., Jones, K. T. and McDougall, A. 2003. Exploring the mechanism of action of the sperm-triggered calcium-wave pacemaker in ascidian zygotes. J. Cell Sci. 116: 4997-5004.
Chadwick-Furman, N. E. and Weissman,
Chen, J. Y., Huang, D. Y., Peng, Q. Q., Chi, H. M., Wang, X. Q. and Feng, M. 2003. The first tunicate from the Early Cambrian of South China. Proc. Nat. Acad. Sci. 100: 8314-8318.
Chill, L., Aknin, M. and Kashman, Y. 2003. Barrenazine A and B; two new cytotoxic alkaloids from an unidentified tunicate. Org. Lett. 5: 2433-2435.
Cima, F., Basso, G. and Ballarin, L. 2003. Apoptosis and phosphatidylserine-mediated recognition during the take-over phase of the colonial life-cycle in the ascidian Botryllus schlosseri. Cell Tiss. Res. 312: 369–376.
Cleto, C. L., Vandenberghe, A. E., MacLean, D. W., Pannunzio, P., Tortorelli, C., Meedel, T. H., Satou, Y., Satoh, N. and Hastings, K. E. 2003. Ascidian larva reveals ancient origin of vertebrate-skeletal-muscle troponin I characteristics in chordate locomotory muscle. Mol. Biol. Evol. 29: 29.
Copp, B. R., Kayser, O., Brun, R. and Kiderlen, A. F. 2003. Antiparasitic activity of marine pyridoacridone alkaloids related to the ascididemins. Planta Med. 69: 527-531.
D'Aniello, A., Spinelli, P., De Simone, A., D'Aniello, S., Branno, M., Aniello, F., Fisher, G. H., Di Fiore, M. M. and Rastogi, R. K. 2003. Occurrence and neuroendocrine role of D-aspartic acid and N-methyl-D-aspartic acid in Ciona intestinalis. FEBS Lett. 552: 193-198.
Davidson, B. and Levine, M. 2003. Evolutionary origins of the vertebrate heart: specification of the cardiac lineage in Ciona intestinalis. Proc. Nat. Acad. Sci. 100: 11469-11473.
Davidson, B., Smith Wallace, S. E., Howsmon, R. A. and Swalla, B. J. 2003. A morphological and genetic characterization of metamorphosis in the ascidian Boltenia villosa. Dev. Genes & Evol. .
Ebner, B., Burmester, T. and Hankeln, T. 2003. Globin genes are present in Ciona intestinalis. Mol. Biol. Evol. 20: 1521-1525.
Fanelli, A., Lania, G., Spagnuolo, A. and Di Lauro, R. 2003. Interplay of negative and positive signals controls endoderm-specific expression of the ascidian Cititf1 gene promoter. Dev. Biol. 263: 12-23.
Flood, P. R. 2003. House formation and feeding behaviour of Fritillaria borealis (Appendicularia: Tunicata). 143: 467 - 475.
Fujiwara, S. and Kawamura, K. 2003. Acquisition of retinoic acid signaling pathway and innovation of the chordate body plan. Zool. Sci. 20: 809-818.
Gissi, C. and Pesole, G. 2003. Transcript mapping and genome annotation of ascidian mtDNA using EST data. Genome Res. 13: 2203-2212.
Groepler, W. and Schuett, C. 2003. Bacterial community
in the tunic matrix of a colonial ascidian Diplosoma migrans.
Hirose, E., Shirae, M. and Saito, Y. 2003. Ultrastructures and classification of circulating hemocytes in 9 botryllid ascidians (Chordata: Ascidiacea). Zool. Sci. 20: 647-656.
Hotta, K., Takahashi, H., Ueno, N. and Gojobori, T. 2003. A genome-wide survey of the genes for planar polarity signaling or convergent extension-related genes in Ciona intestinalis and phylogenetic comparisons of evolutionary conserved signaling components. Gene 317: 165-185.
Huang, Y., Feng, D. Q., Ke, C. H. and Zhou, S. Q.
2003. The determination of larval metamorphic competence of Styela
Imai, K. S. 2003. Isolation and characterization of beta-catenin downstream genes in early embryos of the ascidian Ciona savignyi. Differentiation 71: 346-360.
Imai, K. S., Satoh, N. and Satou, Y. 2002. Region specific gene expressions in the central nervous system of the ascidian embryo. Mech. Dev. 119: S275-277.
Imai, K. S., Satoh, N. and Satou, Y. 2003. A Twist-like bHLH gene is a downstream factor of an endogenous FGF and determines mesenchymal fate in the ascidian embryos. Development 130: 4461-72.
Inada, K., Horie, T., Kusakabe, T. and Tsuda, M. 2003. Targeted knockdown of an opsin gene inhibits the swimming behaviour photoresponse of ascidian larvae. Neurosci. Lett. 347: 167-170.
Ishibashi, M., Nakazawa, M., Ono, H., Satoh, N., Gojobori, T. and Fujiwara, S. 2003. Microarray analysis of embryonic retinoic acid target genes in the ascidian Ciona intestinalis. 45: 249-259.
Izumi Nakaseko, H., Yamaguchi, S., Ohtsuka, Y., Ebihara, T., Adachi Akahane, S. and Okamura, Y. 2003. DHP-insensitive L-type-like Ca channel of ascidian acquires sensitivity to DHP with single amino acid change in domain IIIP-region. FEBS Lett. 549: 67-71.
Jaffe, L. F. 2003. The propagation speeds of calcium action potentials are remarkably invariant. Biol. Cell 95: 343-3455.
Jang, W. S., Kim, C. H., Kim, K. N., Park, S. Y., Lee, J. H., Son, S. M. and Lee, I. H. 2003. Biological activities of synthetic analogs of halocidin, an antimicrobial peptide from the tunicate Halocynthia aurantium. Antimicrobial Agents Chemotherapy 47: 2481-2486.
Jiang, Y. and Doolittle, R. F. 2003. The evolution of vertebrate blood coagulation as viewed from a comparison of puffer fish and sea squirt genomes. Proc. Nat. Acad. Sci. 100: 7527-7532.
Kauffman, J. S., Zinovyeva, A., Yagi, K., Makabe, K. W. and Raff, R. A. 2003. Neural expression of the Huntington's disease gene as a chordate evolutionary novelty. J Exp Zool. B 297: 57-64.
Kawai, N., Shimada, M., Kawahara, H., Satoh, N. and Yokosawa, H. 2003. Regulation of ascidian Rel by its alternative splice variant. Eur. J. Biochem. 270: 4459-4468.
Kimura, Y., Yoshida, M. and Morisawa, M. 2003. Interaction between noradrenaline or adrenaline and the beta 1-adrenergic receptor in the nervous system triggers early metamorphosis of larvae in the ascidian, Ciona savignyi. Dev. Biol. 258: 129-140.
Kobayashi, K., Sawada, K., Yamamoto, H., Wada, S., Saiga, H. and Nishida, H. 2003. Maternal macho-1 is an intrinsic factor that makes cell response to the same FGF signal differ between mesenchyme and notochord induction in ascidian embryos. Development 130: 5179-90.
Kondoh, K., Kobayashi, K. and Nishida, H. 2003. Suppression of macho-1-directed muscle fate by FGF and BMP is required for formation of posterior endoderm in ascidian embryos. Development 130: 3205-3216.
Kott, P. 2002. Ascidiacea (Tunicata) from
Kotterman, M., van der Veen,
Kowalke, J., Tatián, M., Sahade, R. and Arntz, W. 2001. Production and respiration of Antarctic ascidians. Polar Biol. 24: 663-669.
Koyanagi, R. and Honegger, T. G. 2003. Molecular cloning and sequence analysis of an ascidian egg B-N-acetylhexosaminidase with a potential role in fertilization. Develop. Growth Differ. 45: 209-218.
Krasznai, Z., Morisawa, M., Krasznai, Z. T., Morisawa, S., Inaba, K., Bazsane, Z. K., Rubovszky, B., Bodnar, B., Borsos, A. and Marian, T. 2003. Gadolinium, a mechano-sensitive channel blocker, inhibits osmosis-initiated motility of sea- and freshwater fish sperm, but does not affect human or ascidian sperm motility. Cell Motil. Cytoskel. 55: 232-243.
Kurabayashi, A., Okuyama, M., Ogawa, M., Takeuchi, A., Jing, Z., Naganuma, T. and Saito, Y. 2003. Phylogenetic position of a deep-sea ascidian, Megalodicopia hians, inferred from the molecular data. Zool. Sci. 20: 1243-1247.
Lambert, C. C. and Lambert, G. 2003. Persistence and differential distribution of nonindigenous ascidians in harbors of the Southern California Bight. Mar. Ecol. Prog. Ser. 259: 145-161.
Lehrer, R. I., Tincu, J. A., Taylor, S. W., Menzel, L. P. and Waring, A. J. 2003. Natural peptide antibiotics from tunicates: Structures, functions and potential uses. Integrative & Comp. Biol. 43: 313-322.
Locke, A., Hanson, J. M., Ellis, K. M., Klassen, G.
J., Garbary, D. and MacNair, N. G. 2003. Effects of recent invasions on
ecosystems in the southern
López-Urrutia, A., Acuña, J. L., Irigoien, X. and Harris, R. 2003. Food limitation and growth in temperate epipelagic appendicularians (Tunicata). Mar. Ecol. Prog. Ser. 252: 143-157.
López-Urrutia, A., Irigoien, X., Acuña, J. L. and Harris, R. 2003. In situ feeding physiology and grazing impact of the appendicularian community in temperate waters. Mar. Ecol. Prog. Ser. 252: 125-141.
Madhupratap, M., Gauns, M., Ramaiah, N., Kumar, S. P.,
Muraleedharan, P. M., de Sousa, S. N., Sardessai, S. and Muraleedharan, U.
2003. Biogeochemistry of the
Marcellini, S., Technau, U., Smith, J. C. and Lemaire, P. 2003. Evolution of Brachyury proteins: identification of a novel regulatory domain conserved within Bilateria. Dev. Biol. 260: 352-361.
Marshall, D. J. and Keough, M. J. 2003. Variation in the dispersal potential of non-feeding invertebrate larvae: the desperate larva hypothesis and larval size. Mar. Ecol. Prog. Ser. 255: 145-153.
Marshall, D. J. and Keough, M. J. 2003. Effects of settler size and density on early post- settlement survival of Ciona intestinalis in the field. Mar. Ecol. Prog. Ser. 259: 139-144.
Marshall, D. J. and Keough, M. J. 2003. Sources of variation in larval quality for free spawning marine invertebrates: egg size and the local sperm environment. Invert. Repro. & Dev. 44: 63-70.
Maruyama, K., Hirose, E. and Ishikura, M. 2003. Ultraviolet-light-absorbing tunic cells in didemnid ascidians hosting a symbiotic photo-oxygenic prokaryote, Prochloron. Biol. Bull. 204: 109-113.
McHenry, M. J. and Strother, J. A. 2003. The kinematics of phototaxis in larvae of the ascidian Aplidium constellatum. Mar. Biol. 142: 173-184.
Mendola, D. 2003. Aquaculture of three phyla of marine
invertebrates to yield bioactive metabolites: process developments and
Miya, T. and Nishida, H. 2003. An Ets transcription factor, HrEts, is target of FGF signaling and involved in induction of notochord, mesenchyme, and brain in ascidian embryos. Dev. Biol. 261: 25-38.
Moss, C., Green, D. H., Pérez, B., Velasco, A., Henríquez, R. and McKenzie, J. D. 2003. Intracellular bacteria associated with the ascidian Ecteinascidia turbinata: phylogenetic and in situ hybridisation analysis. Mar. Biol. 143: 99-110.
Murugan, A. and Ramasamy, M. S. 2003. Biofouling deterrent activity of the natural product from ascidian, Distaplia nathensis (Chordata). Indian J. Mar. Sci. 32: 263.
Nagatomo, K. and Fujiwara, S. 2003. Expression of Raldh2, Cyp26 and Hox-1 in normal and retinoic acid-treated Ciona intestinalis embryos. Gene Exp. Patt. 3: 273-277.
Nakahara, S. and Kubo, A. 2003. Total synthesis of styelsamine C, a cytotoxic fused tetracyclic aromatic alkaloid. Heterocycles 60: 2017-2018.
Nakaya, F., Saito, Y. and Motokawa, T. 2003. Switching of metabolic-rate scaling between allometry and isometry in colonial ascidians. Proc. R. Soc. Lond. B 270: 1105-1113.
Newlon, A. W. I., Yund, P. O. and Stewart-Savage, J. 2003. Phenotypic plasticity of reproductive effort in a colonial ascidian, Botryllus schlosseri. J. Exp. Zool. 297A: 180-188.
Newman, L. J. and Schupp, P. 2002. A new species of pseudocerotid flatworm (Platyhelminthes, Polycladida) from the Indo-Pacific. Micronesica 34: 177-184.
Ogasawara, M. and Satou, Y. 2003. Expression of FoxE and FoxQ genes in the endostyle of Ciona intestinalis. Dev. Genes & Evol. 213: 416-419.
Oishi, T., Tsuchikawa, H., Murata, M., Yoshida, M. and Morisawa, M. 2003. Synthesis of endogenous sperm-activating and attracting factor isolated from ascidian Ciona intestinalis. Tet. Lett. 44: 6387-6389.
Okamura, Y., Izumi-Nakaseko, H., Nakajo, K., Ohtsuka, Y. and Ebihara, T. 2003. The ascidian dihydropyridine-resistant calcium channel as the prototype of chordate L-type calcium channel. Neurosignals 12: 142-158.
Parrinello, N., Arizza, V., Chinnici, C., Parrinello, D. and Cammarata, M. 2003. Phenoloxidases in ascidian hemocytes: characterization of the pro-phenoloxidase activating system. Comp. Biochem. Physiol. 135: 583-591.
Parrinello, N., Cammarata, M., Arizza, V., Vazzana, M. and Cooper, E. L. 2003. How do the cells of the invertebrate immune system kill the other cells? In: Legakis, A., Sfenthourakis, S., Polymeni, R. and Thessalou-Legaki, M. (ed.), The New Panorama of Animal Evolution. Proc. 18th Intl. Congr. Zoology. pp. 167-175.
Paz, G., Douek, J., Mo, C., Goren, M. and Rinkevich,
B. 2003. Genetic structure of Botryllus schlosseri (Tunicata) populations
from the Mediterranean coast of
Pemberton, A. J., Hughes, R. N., Manriquez, P. H. and Bishop, J. D. D. 2003. Efficient utilisation of very dilute aquatic sperm: sperm competition may be more likely than sperm limitation when eggs are retained. Proc. R. Soc. Lond. B 270S: S223-S226.
Perez, M., Sadqi, M., Munoz, V. and
Permanyer, J., Gonzàlez-Duarte, R. and Albalat, R. 2003. The non-LTR retrotransposons in Ciona intestinalis. New insights into the evolution of chordate genomes. Genome Biol. 4: R73.1-R73.10.
Roman-Silva, D. A., Rivera, L., Morales, T.,
Saito, Y. 2003. Xenogeneic rejection among three botryllids (compound ascidians). Zool. Sci. 20: 581-589.
Saito, Y. and Nagasawa, N. 2003. Studies on Japanese botryllid ascidians III. A new species of the genus Botryllus with a vivid colony color from the vicinity of Shimoda. Zool. Sci. 20: 765-771.
Saito, Y. and Okuyama, M. 2003. Studies on Japanese botryllid ascidians. IV. A new species of the genus Botryllus with a unique colony shape, from the vicinity of Shimoda. Zool. Sci. 20: 1153-1161.
Sardet, C., Nishida, H., Prodon, F. and Sawada, K. 2003. Maternal mRNAs of PEM and macho 1, the ascidian muscle determinant, associate and move with a rough endoplasmic reticulum network in the egg cortex. Development 130: 5839-5849.
Sardet, C., Prodon, F., Dumollard, R., Chang, P. and Chenevert, J. 2002. Structure and function of the egg cortex from oogenesis through fertilization. Dev. Biol. 241: 1-23.
Sasaki, A., Miyamoto, Y., Satou, Y., Satoh, N. and Ogasawara, M. 2003. Novel endostyle-specific genes in the ascidian Ciona intestinalis. Zool. Sci. 20: 1025-1030.
Sasakura, Y., Awazu, S.,
Sasakura, Y., Yamada, L., Takatori, N., Satou, Y. and Satoh, N. 2003. A genomewide survey of developmentally relevant genes in Ciona intestinalis - VII. Molecules involved in the regulation of cell polarity and actin dynamics. Dev. Genes & Evol. 213: 273-283.
Sato, R., Tanaka, Y. and Ishimaru, T. 2003. Species-specific house productivity of appendicularians. Mar. Ecol. Prog. Ser. 259: 163–172.
Satoh, N., Satou, Y., Davidson, B. and Levine, M. 2003. Ciona intestinalis: an emerging model for whole-genome analyses. Trends in Genetics 19: 376-381.
Stotz, W. B., Gonzalez, S. A., Caillaux, L. and Aburto, J. 2003. Quantitative evaluation of the diet and feeding behavior of the carnivorous gastropod, Concholepas concholepas (Bruguiere, 1789) (Muricidae) in subtidal habitats in the southeastern Pacific upwelling system. J. Shellfish Res. 22: 147-164.
Sun, X. T., Okuyama, M.,
Tatián, M., Sahade, R., Kowalke, J., Kivatinitz, S. C. and Esnal, G. B. 2002. Food availability and gut contents in the ascidian Cnemidocarpa verrucosa at Potter Cove, Antactica. Polar Biol. 25: 58-64.
Tosti, E., Romano, G., Buttino,
Tostivint, H. and Vaudry, H. 2003. Le génome de la cione:
une plongée aux origines des vertébrés. Médecine/Sciences (
Tsuda, M., Kusakabe, T., Iwamoto, H., Horie, T., Nakashima, Y., Nakagawa, M. and Okunou, K. 2003. Origin of the vertebrate visual cycle: II. Visual cycle proteins are localized in whole brain including photoreceptor cells of a primitive chordate. Vision Res. 43: 3045-3053.
Ueki, T., Sakamoto, Y., Yamaguchi, N. and Michibata, H. 2003. Bioaccumulation of copper ions by Escherichia coli expressing vanabin genes from the vanadium-rich ascidian Ascidia sydneiensis samea. Appl. & Environ. Microbiol. 69: 6442-6.
Ueki, T., Yamaguchi, N. and Michibata, H. 2003. Chloride channel in vanadocytes of a vanadium-rich ascidian Ascidia sydneiensis samea. Comp. Biochem. Physiol. 136B: 91-98.
van Kesteren, C., de Vooght, M. M., Lopez-Lazaro, L., Mathot, R. A., Schellens, J. H., Jimeno, J. M. and Beijnen, J. H. 2003. Yondelis (trabectedin, ET-743): the development of an anticancer agent of marine origin. Anticancer Drugs 14: 487-502.
Wang, C. P., Yagi, K., Lin, P. J., Jin, D. Y., Makabe,
K. W. and
Wenzel, P. J. and Crews, P. 2003. Probing biotransformation relationships among pyridoacridines by focusing on oxygenated analogues. J. Nat . Prod. 66: 873-875.
Wilt, F. H., Killian, C. E. and Livingston, B. T. 2003. Development of calcareous skeletal elements in invertebrates. Differentiation 71: 237-250.
Yamaguchi, N., Kamino, K., Ueki, T. and Michibata, H. 2003. Expressed sequence tag analysis of vanadocytes in a vanadium-rich ascidian, Ascidia sydneiensis samea. Mar. Biotechnol. 6: 6.
Yoshida, M., Horiuchi, Y., Sensui, N. and Morisawa, M. 2003. Signaling pathway from [Ca2+]i transients to ooplasmic segregation involves small GTPase rho in the ascidian egg. Dev. Growth & Differ. 45: 275-281.