The Correlation of Topographically-Derived Relative Wetness with Terrestrial Mollusk Presence and Abundance

Malacologia ◽  
2019 ◽  
Vol 62 (2) ◽  
pp. 225
Keyword(s):  
Terrestrial Mollusk

scholarly journals Assessment of the radiation dose rate for a terrestrial mollusk during chronic Sr-90 irradiation

2019 ◽  
Vol 487 ◽  
pp. 012012
Author(s):  
G V Lavrentyeva ◽  
A E Oorzhak ◽  
R R Shoshina ◽  
A A Oudalova ◽  
Yu A Kurachenko
Keyword(s):  
Radiation Dose ◽  
Dose Rate ◽  
Radiation Dose Rate ◽  
Terrestrial Mollusk

Two Types of Network Oscillations and Their Odor Responses in the Primary Olfactory Center of a Terrestrial Mollusk

2002 ◽  
Vol 87 (6) ◽  
pp. 3160-3164 ◽  
Author(s):  
Yasuko Inokuma ◽  
Tsuyoshi Inoue ◽  
Satoshi Watanabe ◽  
Yutaka Kirino
Keyword(s):  
Spatial Coherence ◽  
Olfactory Receptors ◽  
Slow Oscillation ◽  
Oscillatory Mode ◽  
Fast Oscillation ◽  
Oscillatory Frequency ◽  
Oscillatory Dynamics ◽  
Terrestrial Mollusk ◽  
Network Oscillations ◽  
Extracellular Level

We identified two classes of network oscillations with different frequency ranges in the tentacle ganglion (TG), the primary olfactory center of the terrestrial mollusk Limax marginatus, and investigated the responses of these oscillations to odor inputs. A recent study indicated that there are serotonergic terminals in the TG. We found that when serotonin was applied to the TG, the spontaneous network oscillation of about 1.5 Hz in the TG changed its oscillatory frequency to 0.5 Hz. These two oscillations are distinct, because 1) in most cases, the application of serotonin to the TG initially inhibited the 1.5-Hz oscillation and subsequently generated the slow 0.5-Hz oscillation; and 2) occasionally, the application of serotonin did not inhibit the spontaneous 1.5-Hz oscillation, resulting in the coexistence of two network oscillations. Thus the TG has two different oscillatory dynamics. We named the spontaneous 1.5-Hz oscillation the fast oscillation (FO), and the serotonin-induced 0.5-Hz oscillation the slow oscillation (SO). By calculating the spatial coherence of the TG oscillations, we found that the FO is a noncoherent oscillatory mode and the SO is a coherent oscillatory mode. Finally, odor presentation to the olfactory receptors selectively modulated the SO by decreasing the oscillatory amplitude, but the FO was not modulated by the odor input. These results indicate that 1) the TG has two oscillatory states (FO and SO) and these states are changed by the extracellular level of serotonin, and 2) these two oscillatory states have different responses to odors.

Dynamics of propagating waves in the olfactory network of a terrestrial mollusk: an electrical and optical study

1994 ◽  
Vol 72 (3) ◽  
pp. 1402-1419 ◽  
Author(s):  
D. Kleinfeld ◽  
K. R. Delaney ◽  
M. S. Fee ◽  
J. A. Flores ◽  
D. W. Tank ◽  
...  
Keyword(s):  
Action Potentials ◽  
Field Potential ◽  
Longitudinal Axis ◽  
Optical Signal ◽  
Clear Correlation ◽  
Inhibitory Input ◽  
Electrical Measurements ◽  
Terrestrial Mollusk ◽  
Bursting Neurons ◽  
Intracellular Signals

1. The procerebral (PC) lobe of the terrestrial mollusk Limax maximus contains a highly interconnected network of local olfactory interneurons that receives ipsilateral axonal projections from superior and inferior noses. This network exhibits an approximately 0.7-Hz intrinsic oscillation in its local field potential (LFP). 2. Intracellular recordings show that the lobe contains at least two classes of neurons with activity phase locked to the oscillation. Neurons in one class produce periodic bursts of spikes, followed by a period of hyperpolarization and subsequently a depolarizing afterpotential. There is a small but significant chance for a second burst to occur during the depolarizing afterpotential; this leads to a double event in the LFP. Bursting neurons constitute approximately 10% of the neurons in the lobe. 3. Neurons in the other class fire infrequently and do not produce periodic bursts of action potentials. However, they receive strong, periodic inhibitory input during every event in the LFP. These nonbursting cells constitute the major fraction of neurons in the lobe. There is a clear correlation between the periodic burst of action potentials in the bursting neurons and the hyperpolarization seen in nonbursting neurons. 4. Optical techniques are used to image the spatially averaged transmembrane potentials in preparations stained with voltage-sensitive dyes. The results of simultaneous optical and electrical measurements show that the major part of the optical signal can be interpreted as a superposition of the intracellular signals arising from the bursting and nonbursting neurons. 5. Successive images of the entire PC lobe show waves of electrical activity that span the width of the lobe and travel its full length along a longitudinal axis. The direction of propagation in the unperturbed lobe is always from the distal to the proximal end. The wavelength varies between preparations but is on the order of the length of the preparation. 6. One-dimensional images along the longitudinal axis of the lobe are used to construct a space-time map of the optical activity, from which we calculate the absolute contribution of bursting and nonbursting neurons to the optical signal. The contribution of the intracellular signals from the two cell types appears to vary systematically across the lobe; bursting cells dominate at middle and proximal locations, and nonbursting cells dominate at distal locations. 7. The direction and form of the waves can be perturbed either by microsurgical manipulation of the preparation or by chemical modulation of its synaptic and neuronal properties.(ABSTRACT TRUNCATED AT 400 WORDS)

Exogenous choline augments transmission at an identified cholinergic synapse in terrestrial mollusk Limax maximus

1982 ◽  
Vol 48 (2) ◽  
pp. 439-450 ◽  
Author(s):  
S. R. Barry ◽  
A. Gelperin
Keyword(s):  
Choline Uptake ◽  
Cholinergic Synapse ◽  
Salivary Duct ◽  
Short Term ◽  
Terrestrial Mollusk ◽  
Pharmacological Tests ◽  
Receptor Sites ◽  
Long Term Effect ◽  
Limax Maximus

1. A variety of pharmacological tests indicate that the neuromuscular junction between the salivary burster neuron (SB) and the salivary duct muscle (SD) in the terrestrial mollusk Limax maximus is cholinergic. These include the effects of curare, atropine, and hexamethonium. 2. Exogenously applied choline can act both presynaptically and postsynaptically at the synapse between the SB and SD. a) When the SB-SD synapse is bathed in 30 microM choline, there is no measurable direct postsynaptic effect at the SB-SD synapse. After several hours of choline incubation, however, an increase is observed in the size of SB-elicited junction potentials recorded from the SD. b) When the synapse is bathed in 300 microM choline, a short-term decrease is seen in the amplitudes of junction potentials (JPs) recorded from the SD. This effect is interpreted as competition between choline and acetylcholine (ACh) for postsynaptic receptor sites on the SD, since the response of the denervated SD to ACh is diminished in the presence of 300 microM choline. c) After several hours incubation in 300 microM choline, the amplitudes of JPs elicited by the SB on the SD increase. 3. The long-term effect of exogenous choline is blocked by the choline-uptake inhibitor, hemicholinium 3. 4. We conclude that exogenous choline is taken up by the presynaptic terminals of the SB and converted to ACh. Transmitter output rises with growing transmitter stores, producing an increase in the size of SB-elicited JPs recorded from the SD.

scholarly journals A chromosomal-level genome assembly for the giant African snail Achatina fulica

GigaScience ◽  
2019 ◽  
Vol 8 (10) ◽  
Author(s):  
Yunhai Guo ◽  
Yi Zhang ◽  
Qin Liu ◽  
Yun Huang ◽  
Guangyao Mao ◽  
...  
Keyword(s):  
Pacific Islands ◽  
High Growth ◽  
Reproductive Capacity ◽  
Genome Comparison ◽  
Achatina Fulica ◽  
Sequencing Data ◽  
Protein Coding ◽  
Sequencing Platform ◽  
Protein Coding Genes ◽  
Terrestrial Mollusk

AbstractBackgroundAchatina fulica, the giant African snail, is the largest terrestrial mollusk species. Owing to its voracious appetite, wide environmental adaptability, high growth rate, and reproductive capacity, it has become an invasive species across the world, mainly in Southeast Asia, Japan, the western Pacific islands, and China. This pest can damage agricultural crops and is an intermediate host of many parasites that can threaten human health. However, genomic information of A. fulica remains limited, hindering genetic and genomic studies for invasion control and management of the species.FindingsUsing a k-mer–based method, we estimated the A. fulica genome size to be 2.12 Gb, with a high repeat content up to 71%. Roughly 101.6 Gb genomic long-read data of A. fulica were generated from the Pacific Biosciences sequencing platform and assembled to produce a first A. fulica genome of 1.85 Gb with a contig N50 length of 726 kb. Using contact information from the Hi-C sequencing data, we successfully anchored 99.32% contig sequences into 31 chromosomes, leading to the final contig and scaffold N50 length of 721 kb and 59.6 Mb, respectively. The continuity, completeness, and accuracy were evaluated by genome comparison with other mollusk genomes, BUSCO assessment, and genomic read mapping. A total of 23,726 protein-coding genes were predicted from the assembled genome, among which 96.34% of the genes were functionally annotated. The phylogenetic analysis using whole-genome protein-coding genes revealed that A. fulica separated from a common ancestor with Biomphalaria glabrata ∼182 million years ago.ConclusionTo our knowledge, the A. fulica genome is the first terrestrial mollusk genome published to date. The chromosome sequence of A. fulica will provide the research community with a valuable resource for population genetics and environmental adaptation studies for the species, as well as investigations of the chromosome-level of evolution within mollusks.

scholarly journals Late Miocene–Pliocene Paleoclimatic Evolution Documented by Terrestrial Mollusk Populations in the Western Chinese Loess Plateau

PLoS ONE ◽  
2014 ◽  
Vol 9 (4) ◽  
pp. e95754 ◽  
Author(s):  
Fengjiang Li ◽  
Naiqin Wu ◽  
Denis-Didier Rousseau ◽  
Yajie Dong ◽  
Dan Zhang ◽  
...  
Keyword(s):  
Loess Plateau ◽  
Late Miocene ◽  
Chinese Loess Plateau ◽  
Chinese Loess ◽  
Terrestrial Mollusk
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