CONTENT - International Society of Zoological Sciences

S11 ICZ2008 - Abstracts
The nervous system in orthonectid Intoshia variabili
George Slyusarev
Saint Petersburg State University, Russia
The nervous system in the female orthonectid Intoshia variabili was
revealed by anti-serotonin labeling. The nervous system consists of
two pairs of symmetrically arranged nerve cells. The neuron bodies
lie between the ciliated cells and the muscle cells in the anterior part
of the female body. The anterior nerve cells are multipolar, they are
brought closer together than the posterior pair of neurons and are
located dorsally. A few processes run anteriorly and “ventrally” from
the anterior neuron pair, forming a well developed plexus. Some part
of these processes appears to get in contact with a provisional
sensory organ. Two posterior bipolars are located laterally and each
has a long process running further posteriorly and lying between the
epithelial and the muscle cells. The processes do not reach the very
end of the body, The nervous system in the orthonectid I. variabili is
distinctly bilateral.
The finding of the nervous system in the orthonectids should put an
end to the dispute concerning phylogenetic relationships between
Orthonectida and Diciemyda. The phylums Orthonectida and
Diciemyda cannot be joined in a single group Mesozoa.
Cloning of cyclic AMP responsive element binding protein 1
(CREB1) cDNA in the earthworm Eisenia fetida
Kosuke Watanabe 1 , Sumitaka Hase 2 , Toshinobu Shimoi 1 , Hiroto
Ogawa 3 , Kohji Hotta 1 and Kotaro Oka 1
1 Center for Biosciences and Informatics, School of Fundamental
Science and Technology, Keio University, Hiyoshi, Kohoku-ku,
Yokohama, Kanagawa, Japan ; 2 Faculty of Science and Technology
Experiment Education Support Center, Keio University, Hiyoshi,
Kohoku-ku, Yokohama, Kanagawa, Japan ; 3 Department of Biology,
Faculty of Medicine, Saitama Medical University, Iruma-gun, Saitama,
Japan
The earthworm can be classically conditioned by weak vibration as
conditioned stimulus and by light as unconditioned stimulus. Our
previous study showed that both de novo mRNA and protein
synthesis are required for long-term memory (LTM) formation in the
earthworm, Eisenia fetida. In other words, both transcription and
translation are needed for LTM formation. However, the neurons
involved in LTM formation remain unknown. Cyclic AMP responsive
element binding protein 1 (CREB1) plays an essential role in LTM
formation as a transcription factor in various animals including
Lymnaea stagnalis. The aim of our study is to observe localization of
CREB1 gene in the central nervous system of the earthworm, and
identify the neurons involved in LTM formation.
As a first step, we obtained a partial sequence of CREB1 homolog in
the earthworm, using sets of degenerate primers designed to target
a bZIP domain which is well conserved over hundreds of species of
CREB1. Next, we determined a complete nucleotide sequence of
CREB1 homolog by RACE-PCR, and it was found that obtained
CREB1 has also two domains, bZIP and P-box, like other animals’
CREB1. Our study is the first report of existence of CREB1 in
annelids, which will shed light on the evolution of molecular
mechanism in LTM.
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Inheritance of Color Phenotype in the Sea Urchin Lytechinus
variegatus
Maria L. Wise and Daniel Rittschof
Duke University Marine Laboratory, Beaufort NC 28516, USA
Lytechinus variegatus is a variably colored sea urchin common
throughout the western Atlantic and Caribbean, from Beaufort, North
Carolina to Brazil. Field sampling indicates that coloration in L.
variegatus varies with geographic location and is more variable in
individuals in some locations than in others. The color phenotype of
the spines can be white, green, purple, lavender and pink and is
often a combination of two or more colors. Pawson and Miller’s 1982
experimental crosses of L. variegatus from Florida and Bermuda
demonstrated a genetic link to color inheritance and in this study we
expand on these experiments by creating a series of crosses
involving several color morphs. Early stage juveniles (< 4mm in
horizontal diameter) of all color crosses are very similar in
appearance - translucent white with a central lavender band on the
spines. Color change occurs when juveniles reach approximately 5
mm in horizontal diameter and continues until the adult color
phenotype is evident (approximately 15 mm in diameter). Color in the
F1 generation is complex suggesting it is a multigene trait for both the
spines and test. Experiments to create an F2 generation are ongoing
and may help shed light on the mode of color inheritance.
Brain development in cephalopod molluscs studied by means of
immunohistochemistry and gene expression analysis
Tim Wollesen and Andreas Wanninger
Department of Biology, Research Group For Comparative Zoology,
University of Copenhagen, Copenhagen, Denmark
Among invertebrates, cephalopod molluscs such as squids, cuttlefish,
octopuses and nautiluses are known for their sophisticated behavior
and cognitive abilities resembling those of vertebrates. Their central
nervous system (CNS) represents an integrative part of their
evolutionary success and has been subject of a wealth of studies
employing classic neuroanatomical methods. However, to date there
are virtually no comparative investigations on the distribution of
neurotransmitters within the developing CNS of cephalopods. In this
study we compare the gross anatomy of the CNS of adults and
developmental stages of selected coleoid cephalopod species by
means of immunohistochemistry combined with confocal laser
scanning microscopy. We investigated the distribution of the neural
markers FMRFamide and acetylated α-tubulin in combination with
phalloidin staining in the brain of the pygmy squid Idiosepius
notoides, the cuttlefish Sepia officinalis, the loliginid squid Loligo
vulgaris, the sepiolid squid Euprymna scolopes and the octopod
Argonauta argo. Moreover, FMRFamidergic gene expression during
CNS development of Idiosepius are provided. This approach aims at
characterizing the expression of certain neural markers in the various
brain lobes during ontogeny in order to generate a highly resolved
atlas of cephalopod neurogenesis in time and space.
The neuropil in the CNS of all above mentioned cephalopod species
is intensely labeled by phalloidin and exhibits strong α-tubulinergic
immunoreactivity. FMRFamidergic structures show a restricted
distribution and comprise cell somata within the cerebral ganglia and
neurites of the circumoesophageal nerve ring. Although certain traits
are shared among the species studied, others are highly species
specific.