I. Control of Microtubule Sliding in Cilia We will directly test the current model of how the force-generating machinery in cilia is controlled to produce bending motion. By using a uniquely advantageous system - macrocilia from the ctenophore Beroe - we will apply the ATP-induced sliding disintegration method of Summers and Gibbons (1971), together with cinemicrography and electron microscopy, to see if bending is caused by alternate activation and inactivation of dynein arms on opposite sides of the axoneme. Because ciliary and flagellar motion is responsible for fluid and particle transport in human respiratory and reproductive systems, as well as for sperm motility, the project is strongly related to certain health problems. II. Electrical Control of Ciliary Motor Responses in Metazoans The activity of cilia and flagella can be modified by the organism to make adaptive responses to environmental stimuli. We will use newly-discovered ciliary motor responses of ctenophore comb plates - a system allowing clear visualization of ciliary beating and cellular electrophysiology - to investigate the ionic and nervous control of ciliary motion in metazoans. Extracellular stimulation of ciliary responses, intracellular recordings from comb plate cells, and current injection will be combined with high-speed video microscopy to give simulataneous recording of electromechanical coupling. This project complements Part I by providing information on the bioelectric control of ciliary motor states in metazoans. III. Mechanism of an Eukaryotic Rotary Motor We will investigate the mechanism of a unique type of motility in an eukaryotic cell: continual, unidirection rotation of one part relative to the other, driven by a rotary axostyle. We will determine whether the rotary motor operates by a conventional actomyosin mechanism, but with a circular geometry of interacting elements. Recently devised ATP-reactivated models of the rotary axostyle will be modified to permit access of specific macromolecular probes. These inhibitors will also be microinjected into living cells and ATP-models. Identity and polarity of presumed actin filaments will be tested by electron microscopic cytochemistry. The protein composition of the axostyle will be analyzed by biochemical methods. This project will enlarge our understanding of the types of motility and filament geometry possible based on actomyosin mechanochemistry.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM027903-10
Application #
3275116
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Project Start
1980-05-01
Project End
1991-04-30
Budget Start
1989-05-01
Budget End
1991-04-30
Support Year
10
Fiscal Year
1989
Total Cost
Indirect Cost
Name
Boston University
Department
Type
Schools of Arts and Sciences
DUNS #
604483045
City
Boston
State
MA
Country
United States
Zip Code
02118
Moss, A G; Tamm, S L (1993) Patterns of electrical activity in comb plates of feeding Pleurobrachia (Ctenophora). Philos Trans R Soc Lond B Biol Sci 339:1-16
Tamm, S; Tamm, S (1991) Actin pegs and ultrastructure of presumed sensory receptors of Beroe (Ctenophora). Cell Tissue Res 264:151-9
Tamm, S; Tamm, S (1990) Ca/Ba/Sr-induced conformational changes of ciliary axonemes. Cell Motil Cytoskeleton 17:187-96
Tamm, S L (1989) Control of reactivation and microtubule sliding by calcium, strontium, and barium in detergent-extracted macrocilia of Beroe. Cell Motil Cytoskeleton 12:104-12
Tamm, S L; Tamm, S (1989) Calcium sensitivity extends the length of ATP-reactivated ciliary axonemes. Proc Natl Acad Sci U S A 86:6987-91
Tamm, S; Tamm, S L (1989) Extracellular ciliary axonemes associated with the surface of smooth muscle cells of ctenophores. J Cell Sci 94 ( Pt 4):713-24
Tamm, S L (1988) Iontophoretic localization of Ca-sensitive sites controlling activation of ciliary beating in macrocilia of Beroe: the ciliary rete. Cell Motil Cytoskeleton 11:126-38
Tamm, S; Tamm, S L (1988) Development of macrociliary cells in Beroe. I. Actin bundles and centriole migration. J Cell Sci 89 ( Pt 1):67-80
Tamm, S L; Tamm, S (1988) Development of macrociliary cells in Beroe. II. Formation of macrocilia. J Cell Sci 89 ( Pt 1):81-95
Tamm, S L (1988) Calcium activation of macrocilia in the ctenophore Beroe. J Comp Physiol A 163:23-31

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