Number 48 December 2000
This issue marks our completion of 25 years of producing
Ascidian News. The newsletter was started by Don Abbott and Lu Eldredge
in 1966; we took over after the third issue. Far from tiring of it
or getting “burned out”, we feel more enthusiastic than ever about the
exciting new discoveries coming from so many laboratories. It is
your contributions that fill these pages; please continue to send them.
As long as AN is useful we hope to continue with it for many more years.
There are more than 90 new papers listed in this issue of AN. Thanks
very much to all of you for sending us your reprints.
We greatly enjoyed the ISOBA meetings in Sapporo at the
end of June. The breadth and quality of the talks and posters were
excellent and we look forward to seeing the published version soon in the
Proceedings volume, which Hitoshi Sawada assures us is progressing splendidly.
It will be published by Springer (Tokyo) early in 2001. After the
meetings we visited a number of interesting places in southern Hokkaido.
Dr. Billie Swalla has the thanks of all ascidologists for generously volunteering
to organize the next ascidian meeting in 3 years, tentatively planned to
be held in Honolulu.
In July we attended a symposium at Scripps in honor of
Vic Vacquier where Charley presented a poster on sperm competition.
In August we participated in 3 nonindigenous species surveys on both US
coasts, of which more will be found in the Work in Progress section.
In October Gretchen presented a paper on nonindigenous ascidians in tropical
waters at the Intl. Coral Reef Symposium in Bali. The weather was
sunny and warm, quite a contrast to Seattle; we spent a week traveling
around the island after the meetings.
George Mackie and Mike Thorndyke have initiated an exciting
new electronic discussion list for all ascidiologists. This makes
it possible to enter into all sorts of interesting dialogues via email
on ascidians. We are most grateful to George and Mike for setting
this up. Judging from the spirited flow of letters so far, it is
a fantastic success (more than 150 subscribers already). For those
of you who have not yet joined, please see the instructions below.
And don’t worry about having missed anything; already-sent letters are
in an archive on the website.
We will be at the Friday Harbor Labs from mid-December
until mid-January and then again next summer when Charley will teach the
comparative invertebrate embryology class with Mark Martindale. As
always, our email addresses remain the same wherever we go, and we always
enjoy hearing from you.
*Ascidian News is not part of the scientific literature and should not be cited as such.
NEWS AND VIEWS
1. George Mackie and Michael Thorndyke have created an
internet discussion forum for topics on the Tunicata. It has already proven
to be extremely useful, and we congratulate George and Mike on this accomplishment.
The list is intended for discussion of all aspects of the biology of tunicates,
including questions concerning early chordate evolution. The list
is an "open" one. That means anyone can join and leave, send messages,
see who else is on the list or search archived messages on the web page.
The list server recently changed but all the archives have been transferred
to the new site.
To join the list send a message to jiscmail@jiscmail.ac.uk
saying: join tunicata first name last name
You will receive an acknowledgment giving information on how to send
messages and commands.
You can also join or leave the list or browse the archives etc. by
going to: http://www.jiscmail.ac.uk/lists/tunicata.html
2. From Karen Sanamyan, Kamchatka Institute of Ecology, Russia
(terra@mail.kamchatka.ru),
who has an exciting new software ascidian taxonomic database for sale that
works in Windows 95/98.
ZooBase is a tool for professional taxonomists
and systematists designed for navigating through literature, taxonomic
descriptions and synonymies of nominal species. It provides information
on who has described this species as valid and in what publications (with
complete citations), complete synonymies of every species in the database
and so on. With cross-referencing, the user can search all references
that include a particular species, or all references by a particular author,
etc. There are currently several systematics software programs on
the market; some of them are simply electronic keys for species identification
(useful for students, but not for specialists), others require drawing
up a list of valid species. But how do you proceed if one specialist says
that a certain species is invalid, while others continue to use this name
as valid? This problem does not exist in ZooBase. ZooBase is a collection
of headings of species descriptions compiled from taxonomic papers, accompanied
by the synonyms given in these papers. The search system allows the
user to find the necessary records and display them in the proper format.
ZooBase contains a large database on Ascidiacea of about
17,000 records and a smaller Actiniaria database of 6800 records.
To use the databases, a customer should purchase both the program shell
(3Mb; $120.00) and the Ascidiacea/Actiniaria databases (958KB; $390.00).
Thus the total price is $510.00. The databases will not work without
the program shell (like an Excel spreadsheet will not work without the
Microsoft Excel program). On the other hand, if someone purchases
only the program shell, he can build his own database - (I have sold one
copy to an ichthyologist). The Ascidiacea database (958KB) is a compressed
file with 17000 records, while the program shell is an engine that retrieves
and shows the records from the database. All updates will be free
for registered users.
You can view a sample page from the database on my website,
or download a small trial version of ZooBase to try it before purchasing.
Although the unregistered version has many restrictions (it is read-only
and the demo database is small) it is still useful, because it contains
about 1000 taxonomic papers on Ascidiacea.
To purchase the full version, please visit http://www.taxon.newmail.ru
and follow the order link, which will direct you to Secure Order Form for
ZooBase on the http://www.RegSoft.com
server. This server allows online ordering via credit card, FAX, postal
mail ordering, phone ordering, etc. After registering, you will receive
password and registration info to remove all limitations of the unregistered
version. BUT BETTER, please contact me directly - sanamyan@newmail.ru.
If this address does not work or you have difficulty accessing the Zoobase
homepage, please contact me at terra@mail.kamchatka.ru.
Note from Gretchen: I have used the database and am very enthusiastic about it. It is amazingly easy to use, has a large number of entries and the cross-referencing has been very well thought out. All commands are menu driven like other programs in Microsoft’s Windows. AN subcriber Imène Meliane, a taxonomist working on the ascidians of Oman, describes it as “excellent” and is finding it invaluable in her own work. “What I most appreciate in this database,” she says, “is that it gives you the synonymies of the species and that's very important when you don't know that a species has changed.” We think this will be an indispensable tool for many ascidiologists.
3. Congratulations to Dr. John Faulkner, Professor of marine chemistry at Scripps Institution of Oceanography in La Jalla, California, who was awarded the Paul J. Scheuer Award in Marine Natural Products for outstanding contributions to the field. The award was presented on March 2 at the Gordon Research Conference on Marine Natural Products held in Ventura, Calif. Much of his work has been funded by the Calif. Sea Grant College Program and this announcement was published in their May newsletter.
4. Here is another old silly song for those who like that sort of thing (see Man and the Ascidian by Andrew Lang in AN44 and Amphioxus by Philip Pope in AN47). This one is titled “A Sea Squirt Problem” by Ivar Haglund, who was a very well-known character around Seattle for many years. He started the Ivar’s Acres of Clams restaurants. (We’ll ignore the possibility that he may have been referring to a clam in this song.)
A deep sea problem is troubling me
It may sound as silly as silly can be.
How far, oh how far can a sea squirt squirt?
Will a sea squirt squirt if his feelings are hurt?
The sea-squirt means harm to nobody,
But that doesn’t answer what’s bothering me—
How far, oh how far can a sea squirt squirt?
Will a sea squirt squirt if his feelings are hurt?
I asked sand dollars to tell me how,
But they’re making change and can’t answer me now—
How far, oh how far can a sea squirt squirt?
Will a sea squirt squirt if his feelings are hurt?
He hides in the sand by the ocean blue
Just waiting his chance for a squirt at you.
He loves his work and his eyes simply gleam
When he lets you have it with a salty stream.
No one’s ever figured how far he could
Squirt if he had to, but his aim’s darn good.
5. The 3rd Intl. Symposium on Chemistry and Biological Chemistry of Vanadium will be held in Osaka, Japan Nov. 26-29, 200l. For more information contact Prof. Toshikazu Hirao, hiraov@chem.eng.osaka-u.ac.jp
6. From Bill Austin (baustin@island.net)
Director, Mar. Ecol. Sta., Cowichan Bay, BC, Canada: http://mareco.org/
“I found a number of Styela clava [based on size 10-11cm,
short stalk, triangular form, vertical orientation of siphons, tubercles]
on floats in Birds Eye Cove, Maple Bay, Vancouver Island yesterday (lat.
48 deg. 47.2'N, 123 deg. 36.00'W). A number of transient vessels
dock here, including from WA and CA. Lots of Botrylloides there
too.” We [Lamberts] have followed a population of S. clava
at French Creek (north of Maple Bay on Vanc. Is.) for at least 8 years
but had not found it anywhere else in British Columbia though it is common
at the marina at Blaine, Washington, on the U.S./Canada border. The
Botrylloides
is undoubtedly B. violaceus, now abundant throughout the Pacific
NW.
7. It is with great sadness that we report the death of Professor
Zen-Ichiro Hoshino, who passed away on Oct. 22. A memorial service
was held on Oct. 26 in Morioka. His family, his many friends, and
colleagues will miss him very much. Dr. Takaharu Numakunai writes:
“. Dr. Hoshino's most important contribution to ascidiology is that he
clarified the difference between C. savignyi and C. intesinalis
with Nishikawa-san [Hoshino, Z.-I. and Nishikawa, T. 1985. Taxonomic studies
of Ciona intestinalis (L.) and its allies. Publ. Seto Mar. Biol.
Lab. 30: 61-79]. Now it is very easy for us to distinguish them from
each other, and we can use their gametes without confusion.”
We also have used this important paper many times, most
recently just in the past few weeks, and have given the reference to many
colleagues because of the rapid spread of C. savignyi to new areas
in recent years.
WORK IN PROGRESS
1. From: Imene Meliane (Imene.Meliane@ua.es)
and Alfonso Ramos (alfonso.ramos@ua.es):
We are preparing an article "Records of ascidians (Chordata, Tunicata)
from Oman, south-east of Arabian Peninsula". This will be presented
at the international conference organised by the Sultan Qaboos University
(Oman): "Fisheries, Aquaculture and Environment in the NW Indian Ocean".
The conference will be held January 8-10, 2001. This article is only
a small part of my Ph.D. which will deal with the ascidians of Oman: taxonomy,
ecology and biogeography.
2. Non-indigenous ascidian research: Gretchen and Charles
Lambert. This past summer we participated in rapid assessment
nonindigenous species (NIS) surveys on both U.S. coasts. We surveyed
most of the Massachusetts coastline with a group headed by Judy Pederson
of Mass. Sea Grant program at MIT that included taxonomic specialists in
most marine groups. The following week most of the group continued
with an NIS assessment of Narragansett Bay in Rhode Island, headed by Kevin
Cute, Marine Resources Specialist with the R.I. Coastal Resources Management
Council. The biota on most of the harbor structures was dominated
by huge numbers of non-native ascidians including Ascidiella aspersa,
Styela
clava, Botrylloides violaceus, and Botryllus schlosseri.
Ciona
intestinalis and Diplosoma listerianum were also common at a
few sites. The east coast Ciona is somewhat different from
the west coast C. intestinalis but nevertheless appears to be the
same species. Nowhere in Massachusetts did we find Botrylloides diegensis
although it was intentionally introduced to Eel Pond at Woods Hole some
years ago for genetics studies. A number of recent publications and
reports list B. diegensis on the east coast, but the correct identification
is B. violaceus. Interestingly, although B. violaceus
is now very abundant on the U.S. west coast with a range from Alaska to
Baja Mexico, A. aspersa has not yet appeared on this side of the
continent..
After a few days of recuperation at home we joined an
NIS survey of southern California and Ensenada (Baja Mexico) headed by
Andy Cohen of the San Francisco Estuary Institute. We visited many
of the sites of our 1996-98 nonindigenous ascidian study and the ropes
we installed 4 years ago were still there. Some of these were now
so heavy with Styela plicata that they could not be lifted from
the water and had to be examined length by length under the surface.
It was interesting to see that most of the introduced ascidians listed
in our 1998 paper have continued to flourish. We are including this
new data in a paper in preparation on site-specific analysis of introduced
ascidians in California harbors 1994-2000.
3. From Patrick Frank (frank@SSRL.slac.stanford.edu):
The following is the abstract of a manuscript in preparation, describing
work speciating vanadium in blood cells from Phallusia (Ascidia)
nigra,
and makes some comparisons with Ascidia ceratodes. The differences
are profound.
Unprecedented forms of vanadium observed within the blood
cells of Phallusia (Ascidia) nigra using K-edge X-ray
absorption spectroscopy. P. Franka, W.E. Robinsonb,
K. Kustinc and K.O. Hodgsona,d.
a. Stanford Synchrotron Radiation Lab., SLAC, Stanford Univ., Stanford,
CA 94309. b. Envl., Coastal, & Ocean Sci. Dept., Univ. Mass. Boston,
Boston, MA 02125-3393. c. Dept. Chem., Brandeis Univ., Waltham, MA 02254-9110.
d. Dept. Chem., Stanford Univ., Stanford, CA 94305-5080.
Fits to the vanadium K-edge x-ray absorption spectra (XAS)
of five whole blood cell samples from the tunicate Phallusia (Ascidia)
nigra
revealed unprecedented forms of complexed intracellular vanadium. Endogenous
vanadium was divided between V(III) ion (74.2 ± 5.1% of total V)
and vanadyl ion (VIV=O)2+ (25.2 ± 5.4% of
total V). The V(III) fraction included both [V(H2O)6]3+
(36.7 ± 5.5 %) modeled as VCl3 in 1M HCl, and three previously
unprecedented chelated V(III) forms (37.5 ± 4.6 %). Two of these
could be represented by the model ligand environments V( acetylacetonate)3
(17.9 ± 3.2%) and K3V(catecholate)3 (13.1
± 4.7%), implying DOPA-like complexation. The third chelated form,
present in only four of the samples, was represented by the 7-coordinate
N2O5 complex Na[V(EDTA)(H2O)] (8.0 ±
1.8%) and is suggestive of a novel mononuclear V(III) protein site. It
may have been induced by the DTT uniquely added to these four samples.
Endogenous V(IV) (25.2 ± 5.4%) was principally modeled as VOCl2
in 1M HCl. EPR spectra confirmed the predominance of aquated vanadyl ion.
The fit to the XAS pre-edge energy region of blood cell sample five uniquely
included the XAS spectrum of VOSO4 in 0.1M H2SO4
solution (13.0%), and of [OVV( pivalate)3] (3.1%)
which is also unprecedented. These results are compared with those of analogous
fits to the blood cells of Ascidia ceratodes and support assignment
of P.(A.) nigra to a different genus.
We have a paper in press, due out 25 December in the journal
Inorg. Chem.: Frank, P. and Hodgson, K.O. 2000. Defining chemical species
in complex environments using K-edge X-ray absorption spectroscopy: vanadium
in intact blood cells and Henze solution from the tunicate Ascidia ceratodes.
THESIS ABSTRACTS
Aspects of mate choice in the colonial ascidian Diplosoma listerianum.
Andrew J. Pemberton—Ph.D. thesis, Dept. of Zoology , Univ. of Aberdeen,
Scotland, and Marine Biol. Assoc. of the UK. anp@mba.ac.uk
Supervisors: Dr J.D.D. Bishop (MBA) and Dr L.R. Noble (Aberdeen).
Sessile organisms that release sperm into the environment
but retain their eggs may experience obligate female promiscuity because
a mixture of gametes is received from various potential mates. This
lack of control may be typical of a phylogenetically diverse array of suspension-feeding
aquatic invertebrates that release sperm. Although promiscuity seems
unavoidable it does not follow that females have no control over the extent
or direction of polyandry. I have investigated the extent to which
sperm are actively selected by the colonial ascidian Diplosoma listerianum
– an animal that appears to offer a relatively uncluttered terrain for
the study of late-acting female discrimination.
It seems unlikely that the female role of this hermaphrodite
is sperm-limited. D. listerianum appeared able to utilise
highly dilute sperm to achieve significant rates of fertilisation.
The colonial ascidian achieved comparable levels of fertilisation at sperm
concentrations two or three orders of magnitude lower than is commonly
found with echinoderm species where both eggs and sperm are released.
At a sperm concentration of 100 sperm/ml D. listerianum had near
maximum fertilisation whereas broadcast spawners would display near complete
reproductive failure.
An extensive series of pairwise reciprocal matings between
twelve different clones revealed surprisingly high levels of sexual incompatibility.
Fecundities of crosses varied widely and suggested a continuous scale of
compatibility. Although correlations of compatibility between reciprocal
crosses appeared positive, considerable noise was present in the data and
some crosses showed strongly asymmetrical compatibility. Somatic:gametic
trade-offs may have been detected.
Patterns of sperm precedence in D. listerianum
with a long (five day) interval between matings revealed a consistent initial
advantage toward the first of two acting males. This was thought
to suggest a first-in-first-out utilisation of individual stored gametes.
The proportion of second-male paternity subsequently increased with time,
possibly reflecting an ageing or passive loss of first-male sperm.
Patterns may have been enhanced by the modular nature of the organism,
in that any recently budded zooids would have been available exclusively
to second-male sperm. Estimated P2 for entire progeny arrays was
consistently greater than 0.5, but varied widely.
Two aspects of frequency-dependent selection were studied.
1. In competition with an alternative sperm source, acting males fathered
more progeny if previously mated to a particular female than if no mating
history existed, an advantage probably derived from fertilisations by stored
sperm. 2. When virgin acting female colonies were given mixtures
of sperm at widely divergent concentrations, offspring were shared between
the two sperm sources in approximately the ratio of each mixture.
However, there existed a small but statistically significant deviation
from the fair raffle model, in that sperm at the lower concentration consistently
achieved a greater than expected share of paternity. Environmentally-determined
fixed female preferences could be responsible for this negative frequency
dependence (‘rare male effect’).
Phenotypic plasticity of reproductive effort in the colonial ascidian,
Botryllus
schlosseri. A.W. Newlon, III M.Sc. thesis, Dept. Biological
Sciences, Univ. of New Orleans, Louisiana, USA. Dr. J. Stewart-Savage,
thesis advisor (jssavage@uno.edu).
Phenotypic plasticity, the capability of a genotype
to produce alternative phenotypes depending on the proximate environment,
is considered an adaptive response to temporal and spatial oscillations
in the environment. Since reproductive traits have a significant
influence on overall fitness, and adaptation to environmental change within
the span of a generation is not possible by genetic polymorphism, phenotypic
plasticity of reproductive traits should be selected for in unstable environments.
Selection pressures on reproductive success would be expected to be more
intense in natural populations of short-lived species where reproduction
is limited to a single season. In hermaphroditic species that also
reproduce asexually and are capable of reproductive plasticity, selection
would likely act differently on asexual, male and female reproduction,
and the optimal combinations of traits should change according to the environment.
Previous studies have suggested the possibility for phenotypic plasticity
of male, female and asexual reproductive effort in Damarascotta River populations
of Botryllus schlosseri, a short-lived, hermaphroditic, colonial
ascidian. To test for plasticity in these life-history traits, clones
derived from a down-river population were distributed between their native
site (CI) and a site 10km up-river (DM). Male reproductive effort
was measured by sperm production, female reproductive effort by egg production,
and asexual reproductive effort by growth rate. Data was collected
for the first and third generation of buds born in the field. ANOVA
results indicated plasticity in asexual reproductive effort for the first
generation, and plasticity in all three traits for the third generation.
Phenotypic plasticity in asexual reproductive effort varied significantly
among genets, with a greater variation in the magnitude and direction of
growth rate plasticity between sites during the first generation, than
the third generation. Although there was significant variation in
asexual reproductive plasticity, the randomness of responses implies that
selection is probably weak. Sperm production in the third generation
of buds was lower on average at DM, but there was little variation in the
plasticity of male reproductive effort (i.e., responses were similar in
direction and magnitude across genets), thus selection for large changes
in testis size may be buffered by plasticity. Plasticity in female
reproductive effort in the third generation varied across genets in the
magnitude of response, although the direction was the same (higher egg
production at DM), therefore, selection on female reproductive effort has
great potential for evolutionary change. The cause of higher egg
production at DM may be related to the greater phytoplankton abundance
at that site. Comparisons of the weighted frequency distributions
for reproductive effort of individual buds at each site, demonstrated that
the difference in sperm production between sites was due to an absolute
difference in testis size, while higher egg production at DM was due to
an increase in the proportion of reproductive buds within a colony.
Isolation of a new gene involved in nervous system of the ascidian
Ciona
intestinalis. Salvatore D'Aniello, Lab. Biochim. and Molec. Biol.,
Stazione Zool. A. Dohrn, Villa Comunale, 80121 Napoli, Italy. Thesis
advisor Dr. Margherita Branno (maggy@alpha.szn.it)
In order to identify molecular markers of the ascidian
cell-lineage and/or morphogenetic determinants that could be responsible
for the early commitment in the typical "mosaic" embryo, I've carried out
a survey of the homeobox-containing genes from the cosmopolitan ascidian
Ciona
intestinalis. Between different cDNA clones isolated from our
group I found one homeobox-containing gene that is specifically expressed
in the neural system. Sequence homology of the isolated cDNA clone
demonstrates that it is a member of the paired-like family. The analysis
of the sequence of CiPrx-1, as I named it following the literature
usage, reveals its type of transcriptional factor by the occurrence of
a well conserved homeodomain, consisting of 60 aa, that reveals a high
homology of sequence with PAX and OTX family genes, some more with the
Caenorhabditis
elegans CEH-8 gene and with the well known murine
Prx-2 gene
(formerly called S8). Northern blot analysis shows that the transcript
of the Ciona gene, CiPrx-1, first appears at middle tailbud
stage, peaks at late tailbud and then decreases during the larval stage.
Preliminary in situ hybridization experiments show that CiPrx-1
mRNA first appears at middle tailbud stage in the four cells that are the
precursor of the sensory vesicle; later, at the larva stage, the transcript
is present in some cells around the ocellus in the sensory vesicle.
Structure, expression and transgenic analysis of the Cimshb
gene in Ciona intestinalis. Monia Teresa Russo, Lab. Biochim.
and Molec. Biol., Stazione Zool. A. Dohrn, Villa Comunale, 80121 Napoli,
Italy. Thesis advisor Dr. Margherita Branno (maggy@alpha.szn.it)
This research investigates the regulation of the expression
pattern of the Cimshb gene during the development of Cionaintestinalis
(Aniello et al., 1999, Mech. Dev. 88, 123-126). Cimshb was isolated
from a C.intestinalis cosmid library with a 4.0 Kb promoter region.
I used this sequence to prepare constructs containing different promoter
lengths (4.0 Kb, 3.0 Kb, 1.0 Kb, 0.9 Kb and 0.45 Kb) linked to a lacZ
reporter gene. They were further utilised for electroporation experiments
in which embryos developed until the stage of interest and were then assayed
for ß-galactosidase activity. In larvae the constructs containing
the 4.0 Kb, 3.0 Kb, 1.0 Kb and 0.9 Kb fragments showed the reporter gene
in the primordial pharynx, the sensory vesicle and in the visceral ganglion,
which are the endogenous expression territories. The smallest 0.45 Kb construct
was negative in the primordial pharynx, suggesting that the region extending
from position –450 bp to –900 bp seems to contain the regulatory elements
driving the expression in the primordial pharynx. However this region apparently
contains the elements responsible for expression in the sensory vesicle
and visceral ganglion. In neurulae and tailbud larvae the constructs
containing the 4.0 Kb and the 3.0 Kb fragments induced expression along
the neural folds in the neurula, the neural tube in the tailbud, in the
precursors of otolith and ocellus and in the ventral epidermis (in both
stages) which are endogenous expression territories. The 1.0 Kb fragment
construct lacked expression in the ventral epidermis and in the precursors
of otolith and ocellus, but the signal in the otolith and ocellus precursors
reappeared once again with the shortest 0.9 Kb and 0.45 Kb constructs.
Thus expression in the neural folds and neural tube is driven by regulatory
elements contained in the smallest promoter region, while expression in
the ventral epidermis is driven by elements contained in the region extending
from position –1000 bp to –3000 bp. To interpret the expression in the
sensory vesicle I propose a model requiring at least three regulatory regions
with activating elements at –1000 bp to –3000 bp and the smallest promoter
region; in contrast the region extending from position –900 bp to –1000
bp seems to contain a mild repressor in the presence of the upstream activator.
When the region containing the repressor is absent, the signal appears
after a few hours; but when the second upstream activator is present together
with the repressor, the signal is seen only after some days.
NEW PUBLICATIONS
Abourriche, A., Charrouf, M., Bennamara, A., Berrada, M., Chaib, N., Boudouma, M. and Francisco, C. 1999. Investigation of bioactivity of extracts from Moroccan solitary tunicate Cynthia savignyi. J. Ethnopharmacol. 68: 47-53.
Aiello, A., Carbonelli, S., Esposito, G., Fattorusso, E., Iuvone, T. and Menna, M. 2000. Novel bioactive sulfated alkene and alkanes from the Mediterranean ascidian Halocynthia papillosa. J. Nat. Prod. 63: 1590-1592.
Aiello, A., Fattorusso, E., Menna, M. and Iuvone, T. 2000. Sulcatin, a novel antiproliferative N-methylpyridinium alkaloid from the ascidian Microcosmus vulgaris. J. Nat. Prod. 63: 517-519.
Aknin, M., Dayan, T. L., Rudi, A., Kashman, Y. and Gaydou, E. M. 1999. Hydroquinone antioxidants from the Indian ocean tunicate Aplidium savignyi. J. Agric. Food. Chem. 47: 4175-4177.
Albrieux, M., Moutin, M. J., Grunwald, D. and Villaz, M. 2000. Calmodulin and immunophilin are required as functional partners of a ryanodine receptor in ascidian oocytes at fertilization. Dev. Biol. 225: 101-111.
Albrieux, M. and Villaz, M. 2000. Bilateral asymmetry of the inositol trisphosphate-mediated calcium signaling in two-cell ascidian embryos. Biol. Cell. 92: 277-284.
Ballarin, L., Tonello, C. and Sabbadin, A. 2000. Humoral opsonin from the colonial ascidian Botryllus schlosseri as a member of the galectin family. Mar. Biol. 136: 823-827.
Ballaro, B. and Reas, P. G. 2000. Chemical and mechanical waves on the cortex of fertilized egg cells: a bioexcitability effect. Riv. Biol. 93: 83-101.
Bingham, B. L. and Reitzel, A. M. 2000. Solar damage to the solitary ascidian, Corella inflata. J. Mar. Biol. Ass. U.K. 80: 515-521.
Bishop, J. D., Manriquez, P. H. and Hughes, R. N. 2000. Water-borne sperm trigger vitellogenic egg growth in two sessile marine invertebrates. Proc. R. Soc. Lond. B 267: 1165-1169.
Bishop, J. D., Pemberton, A. J. and Noble, L. R. 2000. Sperm precedence in a novel context: mating in a sessile marine invertebrate with dispersing sperm. Proc. R. Soc. Lond. B 267: 1107-1113.
Caracciolo, A., Di Gregorio, A., Aniello, F., Di Lauro, R. and Branno, M. 2000. Identification and developmental expression of three Distal-less homeobox containing genes in the ascidian Ciona intestinalis. Mech. Dev. 99: 173-176.
Carballo, J. L. 2000. Larval ecology of an ascidian tropical population in a Mediterranean enclosed ecosystem. Mar. Ecol. Prog. Ser. 195: 159-167.
Castilla, J. C. 1998. Las comunidades intermareales de la Bahia San Jorge: estudios de linea base y el programa ambiental de Minera Escondida Ltda. en Punta Coloso. In: Arcos, D. (ed.), Minera del Cobre, Ecologia y Ambiente Costero. pp. 221-244.
Castilla, J. C. 1999. Coastal marine communities: trends and perspectives from human-exclusion experiments. Trends in Ecol. & Evol. 14: 280-283.
Cavagnari, B. M., Tatian, M., Sahade, R. J., Esnal, G. B. and Santome, J. A. 2000. A fatty acid-binding protein and a protein disulphide isomerase-related protein expressed in urochordate gonad cytosol. Int. J. Biochem. Cell Biol. 32: 769-777.
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