scholarly journals The kinematics of swallowing in the buccal mass of Aplysia californica.

1997 ◽  
Vol 200 (4) ◽  
pp. 735-752 ◽  
Author(s):  
R F Drushel ◽  
D M Neustadter ◽  
L L Shallenberger ◽  
P E Crago ◽  
H J Chiel
Keyword(s):  
Lymnaea Stagnalis ◽  
Aplysia Californica ◽  
Spherical Shape ◽  
Shape Space ◽  
Neutral Position ◽  
Buccal Mass ◽  
Internal Structures ◽  
Direction Of Movement ◽  
Dimensional Shape

Changes in the positions, shapes and movements of the feeding apparatus (buccal mass) of the marine mollusc Aplysia californica were studied in intact, transilluminated juveniles. The buccal mass assumes characteristic shapes as its internal structure, the radula/odontophore, moves anteriorly (protracts) or posteriorly (retracts). These shapes are especially distinctive when the radula/odontophore has protracted forwards fully, is close to its resting or neutral position, or has retracted backwards fully. We refer to the shapes that occur at full protraction, transition and full retraction as shape 1 (spherical), shape 2 (ovoid) and shape 3 (gamma-shaped), respectively. We introduce this shape nomenclature in order to avoid confusion with the existing terms protraction and retraction, which we reserve exclusively to describe the direction of movement of the radula/odontophore. The observed shape changes do not agree with those predicted on the basis of in vitro observations of a feeding head preparation, but are similar to shapes observed in vitro in the snail Lymnaea stagnalis. The buccal mass also rotates approximately 10 degrees dorsally during retraction, pivoting on the attachment to the mouth, before the subsequent protraction and return of the buccal mass to the transition shape. This rotation may be due to activation of the extrinsic muscles of the buccal mass. Plots of the buccal mass shape parameters eccentricity versus ellipticity create a two-dimensional shape space, which accurately quantifies the subtle transitions of shape between the different phases of the feeding cycle. Quantitative differences are observed between pure swallows and swallows with tearing behavior, but the qualitative shapes are similar. Hysteresis in the shape space plots of most swallows provides evidence for the hypothesis that protraction and retraction each have distinct 'active' and 'return' phases. The observed kinematic pattern imposes constraints on the internal structures of the buccal mass and may be used to infer the shape and positions of the radula and odontophore.

Kinematic models of the buccal mass of Aplysia californica.

1998 ◽  
Vol 201 (10) ◽  
pp. 1563-1583 ◽  
Author(s):  
R F Drushel ◽  
D M Neustadter ◽  
I Hurwitz ◽  
P E Crago ◽  
H J Chiel
Keyword(s):  
Neural Control ◽  
Kinematic Model ◽  
Aplysia Californica ◽  
Relative Location ◽  
Marine Mollusc ◽  
Buccal Mass ◽  
Kinematic Models ◽  
Made In

The feeding behavior of the marine mollusc Aplysia californica is an intensively studied model system for understanding the neural control of behavior. Feeding movements are generated by contractions of the muscles of the buccal mass. These muscles are internal and cannot be visualized during behavior. In order to infer the movements of the muscles of the buccal mass, two kinematic models were constructed. The first kinematic model assumed that the complex consisting of the pincer-like radula and the underlying odontophore was spherical in shape. In this model, the radula/odontophore was moved anteriorly or posteriorly and the more superficial buccal muscles (I1/I3 and I2) were fitted around it. Although the overall buccal mass shapes predicted by this model were similar to those observed in vivo during protraction, the shapes predicted during retraction were very different. We therefore constructed a second kinematic model in which the shape of the radula/odontophore was based on the shapes assumed by those structures in vitro when they were passively forced into protraction, rest or retraction positions. As each of these shapes was rotated, the second kinematic model generated overall shapes of the buccal mass that were similar to those observed in vivo during swallowing and tearing, and made predictions about the antero-posterior length of the buccal mass and the relative location of the lateral groove. These predictions were consistent with observations made in vivo and in vitro. The kinematic patterns of intrinsic buccal muscles I1 and I2 in vivo were estimated using the second model. Both models make testable predictions with regard to the functions and neural control of intrinsic buccal muscles I2 and I3.

NEURONAL FEEDBACK IN EGG-LAYING BEHAVIOUR OF THE POND SNAIL LYMNAEA STAGNALIS

1993 ◽  
Vol 178 (1) ◽  
pp. 251-259 ◽  
Author(s):  
G. P. Ferguson ◽  
A. W. Pieneman ◽  
R. F. Jansen ◽  
A. Ter Maat
Keyword(s):  
Lymnaea Stagnalis ◽  
Aplysia Californica ◽  
Experimental System ◽  
Egg Laying ◽  
Neuroendocrine Cells ◽  
Behaviour Pattern ◽  
Pond Snail ◽  
Egg Laying Behaviour

The egg-laying behaviour of gastropod molluscs is controlled by peptidergic neuroendocrine cells and has provided an important experimental system for behavioural neurobiology. The genes that code for multiple peptides have been sequenced and the peptides themselves have been identified, thus enabling us to investigate how they act on the nervous system to produce the overt behavioural pattern (reviewed by Geraerts et al. 1988). The two animals that have been studied most extensively are the opisthobranch Aplysia californica and the pulmonate Lymnaea stagnalis. In both cases, the peptidergic neurones controlling egg laying are normally electrically silent (both in vivo and in vitro; Kupfermann, 1967; Pinsker and Dudek, 1977; Kits, 1980; Ter Maat et al. 1986) and produce multiple peptides (Rothman et al. 1983; Geraerts et al. 1985; Sigvardt et al. 1986), which are cleaved from a common protein precursor (Scheller et al. 1983; Vreugdenhil et al. 1988). Before egg laying, the cells produce a long-lasting discharge of action potentials (Pinsker and Dudek, 1977; Ter Maat et al. 1986). This electrical discharge initiates egg-laying behaviour, and during it the peptides (one of which initiates ovulation) are released into the blood. The demonstration, in Aplysia californica, that these peptides could have various effects on the activity of central neurones (reviewed by Mayeri and Rothman, 1985) led to the hypothesis that egg-laying behaviour is a neuroendocrine fixed action pattern controlled and coordinated by the concerted actions of the released peptides (Scheller and Axel, 1984). This hypothesis is also thought to apply to Lymnaea stagnalis (Vreugdenhil et al. 1988) because of the structural similarities between precursors of Aplysia californica and Lymnaea stagnalis egg-laying hormones. In this paper we investigate how the sequence of the various components of the egg-laying behaviour pattern is achieved.

Kinematics of the buccal mass during swallowing based on magnetic resonance imaging in intact, behaving Aplysia californica

2002 ◽  
Vol 205 (7) ◽  
pp. 939-958 ◽  
Author(s):  
David M. Neustadter ◽  
Richard F. Drushel ◽  
Hillel J. Chiel
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Neural Control ◽  
Aplysia Californica ◽  
Resonance Imaging ◽  
Large Variability ◽  
Marine Mollusc ◽  
Buccal Mass ◽  
Internal Structures ◽  
Freely Moving

SUMMARY A novel magnetic resonance imaging interface has been developed that makes it possible to image movements in intact, freely moving subjects. We have used this interface to image the internal structures of the feeding apparatus (i.e. the buccal mass) of the marine mollusc Aplysia californica. The temporal and spatial resolution of the resulting images is sufficient to describe the kinematics of specific muscles of the buccal mass and the internal movements of the main structures responsible for grasping food, the radula and the odontophore. These observations suggest that a previously undescribed feature on the anterior margin of the odontophore, a fluid-filled structure that we term the prow, may aid in opening the jaw lumen early in protraction. Radular closing during swallowing occurs near the peak of protraction as the radular stalk is pushed rapidly out of the odontophore. Retraction of the odontophore is enhanced by the closure of the lumen of the jaws on the elongated odontophore, causing the odontophore to rotate rapidly towards the esophagus. Radular opening occurs after the peak of retraction and without the active contraction of the protractor muscle 12 and is due, in part, to the movement of the radular stalk into the odontophore. The large variability between responses also suggests that the great flexibility of swallowing responses may be due to variability in neural control and in the biomechanics of the ingested food and to the inherent flexibility of the buccal mass.

scholarly journals Nanovesicles Loaded with Origanum onites and Satureja thymbra Essential Oils and Their Activity against Food-Borne Pathogens and Spoilage Microorganisms

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2124
Author(s):  
Giulia Vanti ◽  
Ekaterina-Michaela Tomou ◽  
Dejan Stojković ◽  
Ana Ćirić ◽  
Anna Rita Bilia ◽  
...  
Keyword(s):  
Essential Oils ◽  
Propylene Glycol ◽  
Antimicrobial Properties ◽  
Spherical Shape ◽  
Food Borne Pathogens ◽  
Food Borne ◽  
Spoilage Microorganisms ◽  
Satureja Thymbra ◽  
Origanum Onites

Food poisoning is a common cause of illness and death in developing countries. Essential oils (EOs) could be effective and safe natural preservatives to prevent and control bacterial contamination of foods. However, their high sensitivity and strong flavor limit their application and biological effectiveness. The aim of this study was firstly the chemical analysis and the antimicrobial evaluation of the EOs of Origanum onites L. and Satureja thymbra L. obtained from Symi island (Greece), and, secondly, the formulation of propylene glycol-nanovesicles loaded with these EOs to improve their antimicrobial properties. The EOs were analyzed by GC-MS and their chemical contents are presented herein. Different nanovesicles were formulated with small average sizes, high homogeneity, and optimal ζ-potential. Microscopic observation confirmed their small and spherical shape. Antibacterial and antifungal activities of the formulated EOs were evaluated against food-borne pathogens and spoilage microorganisms compared to pure EOs. Propylene glycol-nanovesicles loaded with O. onites EO were found to be the most active formulation against all tested strains. Additionally, in vitro studies on the HaCaT cell line showed that nanovesicles encapsulated with EOs had no toxic effect. The present study revealed that both EOs can be used as alternative sanitizers and preservatives in the food industry, and that their formulation in nanovesicles can provide a suitable approach as food-grade delivery system.

Reproduction in Aplysia californica: correlations between egg laying in vivo and egg release in vitro

1980 ◽  
Vol 58 (11) ◽  
pp. 2163-2166 ◽  
Author(s):  
F. Edward Dudek ◽  
Amd Bonnie Soutar ◽  
Stephen S. Tobe
Keyword(s):  
Aplysia Californica ◽  
Egg Laying ◽  
Previous Episode ◽  
Laboratory Conditions ◽  
Release In Vitro

Aspects of egg laying by isolated Aplysia californica and egg release from ovotestis fragments were compared under laboratory conditions. The volume of eggs laid per episode increased as a function of time since the previous episode of egg laying. Egg output in vivo and egg release in vitro were maximal in autumn and minimal in spring, but a factor in the parietovisceral ganglion evoked egg release from ovotestis fragments throughout the year. These data are consistent with previous studies which have suggested that the effects of season and egg-laying history on egg laying involve substantial changes in the ovotestis.

scholarly journals SYNTHESIS OF BENTONITE NANOCLAY AND INCORPORATION OF CASSIA FISTULA LEAF EXTRACT TO FORM ORGANOBENTONITE: CHARACTERIZATION AND ITS BIOMEDICAL APPLICATIONS

2018 ◽  
Vol 11 (9) ◽  
pp. 381
Author(s):  
Anand Raj Lfa ◽  
Jeslin J
Keyword(s):  
Biomedical Applications ◽  
Leaf Extract ◽  
Spherical Shape ◽  
Xrd Analysis ◽  
Antioxidant Property ◽  
Clot Lysis ◽  
Cassia Fistula ◽  
Thrombolytic Activity ◽  
Lysis Activity

Objective: In this work, methanolic leaf extract from Cassia fistula (known as aragvadha) was incorporated into bentonite nanoclay to form organobentonite. This organobentonite of nanosize was further used for its effective biomedical applications since medicinal clay finds its own advantage over decades.Methods: The bentonite nanoclay was produced by energetic stirring followed by centrifugation and was characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR). The organobentonite was produced using freeze and thaw method. Antioxidant property was studied using Molyneux method, and thrombolytic activity was analyzed using in vitro clot lysis method.Results: The nanosize of bentonite nanoclay between 57 and 82 nm with irregular to spherical shape was confirmed using SEM analysis. The sharp diffraction peak in XRD analysis shows the crystalline nature of bentonite nanoclay, and FTIR results revealed the successful incorporation of the methanolic extract within the bentonite nanoclay. The organobentonite exhibits 84.5% antioxidant property as well as 31% clot lysis activity when compared to the extract and the bentonite nanoclay.Conclusion: Thus, the non-toxic and inexpensive bentonite nanoclay have a high aspect ratio with multifarious applications in medicine, food, cosmetics, and health products. Through this study, the bentonite nanoclay modified using plant alkaloid (organobentonite) is found to possess good biomedical property.

Schistosomin: a pronase-sensitive agent in the hemolymph of Trichobilharzia ocellata-infected Lymnaea stagnalis inhibits the activity of albumen glands in vitro

1988 ◽  
Vol 74 (3) ◽  
pp. 228-234 ◽  
Author(s):  
J. Joosse ◽  
R. van Elk ◽  
S. Mosselman ◽  
H. Wortelboer ◽  
J. C. E. van Diepen
Keyword(s):  
Lymnaea Stagnalis ◽  
Trichobilharzia Ocellata

scholarly journals A Facile Method to Synthesize 3D Pomegranate-like Polydopamine Microspheres

2021 ◽  
Vol 9 ◽  
Author(s):  
Farnaz Ghorbani ◽  
Behafarid Ghalandari ◽  
Chaozong Liu
Keyword(s):  
Oxidative Polymerization ◽  
Spherical Shape ◽  
Bone Morphogenetic Protein 2 ◽  
Novel Structure ◽  
Morphogenetic Protein ◽  
Clinical Investigations ◽  
Porous Microstructure ◽  
Dopamine Hydrochloride ◽  
Molecular Calculations

Nanospheres have found versatile applications in the biomedical field; however, their possible harmful effects on immune and inflammatory systems are also a crucial concern. Inspired by a pomegranate structure, we demonstrated a novel structure for the nanostructured microspheres to overcome the drawbacks of nanospheres without compromising their merits. In this study, 3D pomegranate-like polydopamine microspheres (PDAMS) were synthesized by self-oxidative polymerization of dopamine hydrochloride. Herein, controlling the pH during polymerization led to synthesizing homogeneous agglomerated nano-sized spheres (400–2000 nm) and finally forming tunable and monodisperse micron-sized particles (21 µm) with uniform spherical shape porous microstructure. PDAMS interaction with the potential targets, Bone morphogenetic protein-2 (BMP2), Decorin, and Matrilin-1, was investigated via molecular calculations. Theoretical energy analysis revealed that PDAMS interaction with BMP2, Decorin, and Matrilin-1 is spontaneous, so that a protein layer formation on the PDAMS surface suggests application in bone and cartilage repair. It was also observed that PDAMS presented in-vitro degradation within 4 weeks. Here, disappearance of the UV-VIS spectrum peak at 280 nm is accompanied by the degradation of catechol groups. Pomegranate-like PDAMS support the biomimetic formation of hydroxyapatite-like layers, making them appropriate candidates for hard tissue applications. Herein, the appearance of peaks in XRD spectrum at 31.37, 39.57, 45.21, and 50.13° attributed to hydroxyapatite-like layers formation. All these results demonstrated that self-oxidative polymerization under a controllable pH can be a green and straightforward technique for preparing the pomegranate-like PDAMS and providing an innovative basis for further pre-clinical and clinical investigations.

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