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Wednesday, August 5, 2020 | History

2 edition of reversal of ciliary movements of metazoans found in the catalog.

reversal of ciliary movements of metazoans

George Howard Parker

reversal of ciliary movements of metazoans

by George Howard Parker

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  • 25 Currently reading

Published by [Museum of Comparative Zoölogy at Harvard College] in Cambridge, Mass .
Written in English

    Subjects:
  • Metazoa -- Anatomy

  • Edition Notes

    Other titlesAmerican journal of physiology. Vol. 13, no. 1
    Statementby G.H. Parker.
    SeriesContributions from the Zoölogical Laboratory of the Museum of Comparative Zoölogy at Harvard College -- no. 159
    The Physical Object
    Pagination16 p. :
    Number of Pages16
    ID Numbers
    Open LibraryOL19687867M

    Calcium ions are found to be involved in the regulation of a number of motile processes, such as muscular contraction 1, ciliary reversal 2 and cytoplasmic contraction 3.   The ciliary dyneins provide the motor capability, but there are two other linkage proteins in the axoneme as well. There are nexins that join the A-tubule of one doublet to the B-tubule of its adjacent doublet, thus connecting the outer , there are radial spokes that extend from the A tubule of each doublet to the central pair of microtubules at the core of the axoneme.

    The choroid is posterior to the ciliary body, a muscular structure that is attached to the lens by zonule fibers. These two structures bend the lens, allowing it to focus light on the back of the eye. Overlaying the ciliary body, and visible in the anterior eye, is the iris—the colored part of the eye.   Primary ciliary dyskinesia (PCD) is an inherited disorder which affects the movement of tiny hair-like structures on body cells, known as are present on many types of cells, and particularly on those in the respiratory tract. In PCD, the cilia are abnormal, and don’t move correctly.

    A congenital abnormality in which organs in the THORAX and the ABDOMEN are opposite to their normal positions (situs solitus) due to lateral | Explore the latest full-text research PDFs. Mechanisms of suspension feeding are usually described by the physics of inanimate filters. High-speed videorecordings in this study demonstrated that sea urchin larvae concentrate particles without filtration. They actively captured individual particles. At most times and places, the effective strokes of the swimming/feeding ciliary band were away from the circumoral field.


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Reversal of ciliary movements of metazoans by George Howard Parker Download PDF EPUB FB2

"In my opinion it is around these contractile cells that the nervous organs of the higher metazoans have developed, and I therefore believe that these " 4. Bibliographia Physiologica by Concilium Bibliographicum, Concilium Bibliographicum, Zürich () "Ciliary Reversal in metazoans.

Amer. Jonrn. Physiol. Vol. 13 p. XIII. The duration of ciliary reversal of Paramecium caudatum in response to changes in external ionic factors was determined with various ionic compositions of both equilibration and stimulation media. The reversal response was found to occur when calcium reversal of ciliary movements of metazoans book bound by an inferred cellular cation exchange system were liberated in exchange for externally applied cations other than by: In Figure 6, p.

of Volume XII, the ordinates for carbon dioxide beginning at the base line are: grams The excretion per minute before the beginning of work was gram.

It is well known that Paramecium (1) is cathodally galvanotactic in mixtures of sodium and calcium salts because of ciliary reversal at the cathodal end, and that (2) the cilia also may be reversed in solutions rich in monovalent cations or in barium or manganese ions, and (3) the organisms swim backward in these solutions.

It also is well known (Kamada, '31) that Paramecium in solutions of Cited by: 4. Calmodulin has been found in the cilia and it is suggested that it is involved in the control system of the response (Reed et al.

C D Fig. Conceptual diagrams of four types of ciliary responses. Upper trace, ciliary movement. Normal beat and reverse beat are illustrated as upward and downward deflections of the base line, by: ECHINODERM larvae are capable of a variety of complex and apparently coordinated activities involving not only muscular movements but changes in the direction of ciliary beating1,2.

The eight. In Paramecium, it is widely accepted that the reversal of the direction of ciliary beating (ciliary reversal) is induced by an increase in intra-ciliary Ca(2+) levels. The Reversal of Ciliary Movement in Metazoans, Am. Physiol. ((Feb.)) The Reversal of the Effective Stroke of the Labial Cilia of Sea-Anemones by Organic Substances, Parker Am.

Physiol. ((July)) Cilia are minute, harilike processes on the surface of protozoans or of metazoans cells ehich by their motion accomplish locomotion or produce a current.

Each cilium contains a peripheral circle of nine doublet microtubules arranged around two single microtubules. Each microtubule is composed of tubulin gh the mechanism of ciliary movement is not completely under stood.

* Present address: Dept. of Biology, Georgetown University, Washington, D.C. RICHARD BLANQUET Parker (), in studying the ciliary movement of metazoans, noted that high potassium ion concentrations caused extensive discharge of the tentacle nemato- cysts in Metridium.

This has since been confirmed by Pantin () and Yanagita (b). The ciliary reversal response, as shown in Paramecium, is triggered by a membrane depolarization followed by a Ca-influx through voltage-dependent Ca-channels (Naitoh et al., ) which are localized in the ciliary membrane (Ogura & Takahashi, ; Dunlap, ; * Present address: Laboratory of Molecular Biology and Department of Genetics.

Ciliary tip structure The locomotory cilia of the lower metazoans reported on here do have the usual 9+2 pattern of axonemal filaments in the major part of the ciliary shaft, but they also have special arrangements of the axonemal fila- ments making up the ciliary tips.

Membrane control of ciliary movement Thus, a strong inward Ca++ current flows through this channel, delivering a very short (several milliseconds) but strong Call impulse which is responsible for the membrane potential overshoot, for the sudden increase in the internal Ca++ level triggering ciliary reversal, and for its own inactivation.

In conclusion, the direction of fluid movement is irreversibly associated with ciliary orientation, as has been demonstrated by surgical reversal of tracheal segments [Delaere et. Background. Eyes in bilaterian metazoans have been described as being composed of either ciliary or rhabdomeric photoreceptors.

Phylogenetic distribution, as well as distinct morphologies and characteristic deployment of different photopigments (ciliary vs. rhabdomeric opsins) and transduction pathways argue for the co-existence of both of these two photoreceptor types in the last common.

Primary ciliary dyskinesia (PCD), or immotile cilia syndrome (ICS), is an autosomal recessive disorder affecting ciliary movement with an incidence of 1 in Cilia are minute, harilike processes on the surface of protozoans or of metazoans cells which by their motion accomplish locomotion or produce a current.

Each cilium contains a peripheral circle of nine doublet microtubules arranged around two single microtubules. Lucas, A. M.: Coordination of Ciliary Movement: I.

Methods of Study and the Relation of Ciliary G. H.: The Reversal of Ciliary Movement in Metazoans, Am. Physiol. On Permanent Natural Reversal of the Frontal Cilia on the Gill Filaments of Mytilus Edulis, J.

Marine Biol. These results show that ciliary reversal in ctenophores, like that in protozoa, is activated by an increase in intracellular free Ca2+ ions.

This allows the unique experimental advantages of ctenophore comb plate cilia to be used for future studies on the site and mechanism of action of Ca2+ in the regulation of ciliary motion.

High K+ concentrations cause cydippid larvae of the ctenophore Pleurobrachia to swim backward. High-speed cine films of backward-swimming animals show a degree reversal in beat direction of the comb plates.

Ion substitution and blocking experiments with artificial seawaters demonstrate that ciliary reversal is a Ca++-dependent response. ciliary movement: the rhythmic, sweeping movement of epithelial cell cilia, of ciliate protozoans, or the sculling movement of flagella, effected possibly by the alternate contraction and relaxation of contractile threads (myoids) on one side of the cilium or flagellum.The prototroch is the primary ciliary band of spiralians (Nielsen b).

In support of ancestral regulatory entities, cis-regulatory sequences of a gastropod alpha-tubulin gene drive trochoblast expression in the primary ciliary band of various spiralians (Damen et al.

).Movements of Cilia and Flagella 1. Regulation of ciliary movement. Ciliary movement is independent of the nervous system. This is evidenced by the fact that if ciliated epithelium is removed from the organism, the cilia continue to move rhythmically. Cystoplasmic continuity is, however, essential for coordinated movement of cilia.