scholarly journals Identification, molecular structure and expression of two cloned serotonin receptors from the pond snail, Helisoma trivolvis

2008 ◽  
Vol 211 (6) ◽  
pp. 900-910 ◽  
Author(s):  
S. Mapara ◽  
S. Parries ◽  
C. Quarrington ◽  
K.-C. Ahn ◽  
W. J. Gallin ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Serotonin Receptors ◽  
Pond Snail ◽  
Helisoma Trivolvis

Forced Convection Past a Rotating Sphere: Modeling Oxygen Transport to a Pond Snail Embryo

2013 ◽  
Vol 135 (12) ◽  
Author(s):  
D. A. Nield ◽  
A. V. Kuznetsov
Keyword(s):  
Forced Convection ◽  
Quantitative Study ◽  
Oxygen Transport ◽  
Oxygen Transfer ◽  
Pond Snail ◽  
Gaseous Exchange ◽  
Helisoma Trivolvis ◽  
Rotating Sphere

Helisoma trivolvis pond snail embryos are known for their rotation, which is induced by beating of cilia at the embryo's surface. A common hypothesis links this behavior to enhancing oxygen transfer to the embryo's surface. In this paper, this hypothesis is quantified, and the effect of the rotation on the supply of oxygen to an embryo, which is approximately spherical in shape, is studied. To the best of our knowledge, this is the first research presenting a quantitative study on the effect of an embryo's rotation on facilitating gaseous exchange between the embryo and the environment.

Multiple Subtypes of Serotonin Receptors in the Feeding Circuit of a Pond Snail

2011 ◽  
Vol 28 (7) ◽  
pp. 517-525 ◽  
Author(s):  
Ryo Kawai ◽  
Suguru Kobayashi ◽  
Yutaka Fujito ◽  
Etsuro Ito
Keyword(s):  
Serotonin Receptors ◽  
Pond Snail

Regulation of early embryonic behavior by nitric oxide in the pond snail Helisoma trivolvis

2002 ◽  
Vol 205 (20) ◽  
pp. 3143-3152 ◽  
Author(s):  
Alison G. Cole ◽  
Aniseh Mashkournia ◽  
Shawn C. Parries ◽  
Jeffrey I. Goldberg
Keyword(s):  
Nitric Oxide ◽  
Rotation Rate ◽  
Apical Dendrite ◽  
Rotational Behavior ◽  
Pond Snail ◽  
Ciliary Activity ◽  
No Donors ◽  
Helisoma Trivolvis ◽  
Fourfold Increase ◽  
Nos Inhibitors

SUMMARY Helisoma trivolvis embryos display a cilia-driven rotational behavior that is regulated by a pair of serotonergic neurons named ENC1s. As these cilio-excitatory motor neurons contain an apical dendrite ending in a chemosensory dendritic knob at the embryonic surface, they probably function as sensorimotor neurons. Given that nitric oxide (NO) is often associated with sensory neurons in invertebrates, and has also been implicated in the control of ciliary activity, we examined the expression of NO synthase (NOS) activity and possible function of NO in regulating the rotational behavior in H. trivolvis embryos. NADPH diaphorase histochemistry on stage E25-E30 embryos revealed NOS expression in the protonephridia, buccal mass,dorsolateral ciliary cells and the sensory dendritic knobs of ENC1. At stages E35-40, the pedal ciliary cells and ENC1's soma, apical dendrite and proximal descending axon were also stained. In stage E25 embryos, optimal doses of the NO donors SNAP and SNP increased the rate of embryonic rotation by twofold, in contrast to the fourfold increase caused by 100 μmol l-1serotonin. The NOS inhibitors L-NAME (10 mmol l-1) and 7-NI (100μmol l-1) decreased the rotation rate by approximately 50%,whereas co-addition of L-NAME and SNAP caused a twofold increase. In an analysis of the surge and inter-surge subcomponents of the rotational behavior, the NO donors increased the inter-surge rotation rate and the surge amplitude. In contrast, the NO inhibitors decreased the inter-surge rotation rate and the frequency of surges. These data suggest that the embryonic rotational behavior depends in part on the constitutive excitatory actions of NO on ENC1 and ciliary cells.

Molecular Structure of the Outermost Cell Wall Component of Spirillum Serpens

1977 ◽  
Vol 35 ◽  
pp. 342-343
Author(s):  
Wah Chiu ◽  
David Grano
Keyword(s):  
Molecular Structure ◽  
Cell Wall ◽  
Outer Membrane ◽  
Gel Electrophoresis ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Cell Wall Component ◽  
Protein Components ◽  
Exposure Technique ◽  
Structural Aspects

The periodic structure external to the outer membrane of Spirillum serpens VHA has been isolated by similar procedures to those used by Buckmire and Murray (1). From SDS gel electrophoresis, we have found that the isolated fragments contain several protein components, and that the crystalline structure is composed of a glycoprotein component with a molecular weight of ∽ 140,000 daltons (2). Under an electron microscopic examination, we have visualized the hexagonally-packed glycoprotein subunits, as well as the bilayer profile of the outer membrane. In this paper, we will discuss some structural aspects of the crystalline glycoproteins, based on computer-reconstructed images of the external cell wall fragments.The specimens were prepared for electron microscopy in two ways: negatively stained with 1% PTA, and maintained in a frozen-hydrated state (3). The micrographs were taken with a JEM-100B electron microscope with a field emission gun. The minimum exposure technique was essential for imaging the frozen- hydrated specimens.

On the relation between isotope effects on vapour pressure and molecular structure

1963 ◽  
Vol 60 ◽  
pp. 52-55
Author(s):  
István Kiss ◽  
Lajos Matus ◽  
István Opauszky
Keyword(s):  
Molecular Structure ◽  
Vapour Pressure ◽  
Isotope Effects
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