PubMed · 2010190
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
R J Prescott, S Shehade, R H Macdonald. 1991. Cutaneous ciliated cyst.. https://doi.org/10.1111/j.1365-2559.1991.tb01472.x
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Cilia and flagella are microtubule-based organelles that generate force and sense the extracellular environment. In humans, these structures are essential for development, homeostasis, and reproduction, with defects contributing to a wide array of congenital and degenerative disorders. As cilia were present on the last common ancestor of all eukaryotes, research on cilia across model organisms holds significant relevance for understanding human disease. The green alga Chlamydomonas, which diverged from the human lineage with the animal-plant split, shares striking similarities in ciliary structure and function with humans. Two decades ago, our group published the proteome of the Chlamydomonas cilium, identifying hundreds of new ciliary proteins that were organized in an online database. Since then, advances have brought us a more comprehensive understanding of both Chlamydomonas and mammalian cilia. Our database, www.Cilia.Pro, has been continually updated to integrate proteomic, transcriptomic, and genomic data from Chlamydomonas and Caenorhabditis along with humans, and other vertebrates providing a valuable tool for the ciliary research community.
The internal mechanism of cilia is among the most ancient biological motors on an evolutionary scale. It produces beat patterns that consist of two phases: during the effective stroke, the cilium moves approximately as a straight rod, and during the recovery stroke, it rolls close to the surface in a tangential motion. It is commonly agreed that these two phases are designed for efficient functioning: the effective stroke encounters strong viscous resistance and generates thrust, whereas the recovery stroke returns the cilium to starting position while avoiding viscous resistance. Metachronal coordination between cilia, which occurs when many of them beat close to each other, is believed to be an autonomous result of the hydrodynamical interactions in the system. Qualitatively, metachronism is perceived as a way for reducing the energy expenditure required for beating. This paper presents a quantitative study of the energy expenditure of beating cilia, and of the energetic significance of metachronism. We develop a method for computing the work done by model cilia that beat in a viscous fluid. We demonstrate that for a single cilium, beating in water, the mechanical work done during the effective stroke is approximately five times the amount of work done during the recovery stroke. Investigation of multicilia configurations shows that having neighboring cilia beat metachronally is energetically advantageous and perhaps even crucial for multiciliary functioning. Finally, the model is used to approximate the number of dynein arm attachments that are likely to occur during the effective and recovery strokes of a beat cycle, predicting that almost all of the available dynein arms should participate in generating the motion.
The role of the human fallopian tube in reproduction is more than a passive conduit. This organ is involved in oocyte pick-up, fertilization, and embryo transport. Metabolic substrates, cytokines, and immunoglobulins have been identified within the tubal lumen. Complex and coordinated endocrine secretions, neuromuscular activity, and cilial action are required for successful tubal function.