Studies on Cilia

نویسنده

  • Peter Satir
چکیده

This study confirms and extends previous work on the lateral cilia of the fresh-water mussel, Elliptio complanatus, in support of a "sliding filament" mechanism of ciliary motility wherein peripheral filaments (microtubules) do not change length during beat (see Satir, 1967). Short sequences of serial sections of tips are examined in control (nonbeating) and activated (metachronal wave) preparations. Several different tip types, functional rather than morphogenetic variants, are demonstrated, but similarly bent cilia have similar tips. The peripheral filaments are composed of two subfibers: a and b. The bent regions of cilia are in the form of circular arcs, and apparent differences in subfiber-b length at the tip are those predicted solely by geometry of the stroke without the necessity of assuming filament contraction. Various subfibers b apparently move with respect to one another during beat, since small systematic variations in relative position can be detected from cilium to cilium. While subfiber-b lengths are uniform throughout, subfiber-a lengths are morphologically different for each filament: 8 and 3 are about 0.8 micro longer than 1, 4 and 5, but each unique length is independent of stroke position or tip type. Subfiber-a does not contract, nor does it move, e.g. slide, with respect to subfiber-b of the same doublet. The central pair of filaments extends to the tip of the cilium where its members fuse. Subunit assembly in ciliary microtubules is evidently precise. This may be of importance in establishing the relationships needed for mechanochemical interactions that produce sliding and beat.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Effect of Cilia Beat Frequency on Muco-ciliary Clearance

Background: The airway surface liquid (ASL), which is a ï‌‚uid layer coating the interior epithelial surface of the bronchi and bronchiolesis, plays an important defensive role against foreign particles and chemicals entering lungs.Objective: Numerical investigation has been employed to solve two-layer model consisting of mucus layer as a viscoelastic fluid and periciliary liquid layer as a New...

متن کامل

Intralenticular Cilia Following Penetrating Ocular Trauma: A Case Report

Penetrating ocular trauma is one of the most important causes of vision loss, especially in men, and can be associated with intraocular foreign bodies. The incidence of intraocular cilia after trauma is very low. Here we report the case of a 24-year-old man who visited Poostchi Ophthalmology Clinic (Shiraz, Iran) due to a gradual vision loss in his left eye over the past 2 months. The probable ...

متن کامل

Cilia and Flagella Revealed From Flagellar Assembly in Chlamydomonas to Human Obesity Disorders

The recent identification in Chlamydomonas of the intraflagellar transport machinery that assembles cilia and flagella has triggered a renaissance of interest in these organelles that transcends studies on their well-characterized ability to move. New studies on several fronts have revealed that the machinery for flagellar assembly/disassembly is regulated by homologs of mitotic proteins, that ...

متن کامل

The dynamic cilium in human diseases

Cilia are specialized organelles protruding from the cell surface of almost all mammalian cells. They consist of a basal body, composed of two centrioles, and a protruding body, named the axoneme. Although the basic structure of all cilia is the same, numerous differences emerge in different cell types, suggesting diverse functions. In recent years many studies have elucidated the function of 9...

متن کامل

Proteomic Analysis of Mammalian Primary Cilia

The primary cilium is a microtubule-based organelle that senses extracellular signals as a cellular antenna. Primary cilia are found on many types of cells in our body and play important roles in development and physiology. Defects of primary cilia cause a broad class of human genetic diseases called ciliopathies. To gain new insights into ciliary functions and better understand the molecular m...

متن کامل

Rapamycin Increases Length and Mechanosensory Function of Primary Cilia in Renal Epithelial and Vascular Endothelial Cells

Primary cilia arebiophysically-sensitive organelles responsible for sensing fluid-flow and transducing this stimulus into intracellular responses. Previous studies have shown that the primary cilia mediate flow-induced calcium influx, and sensitivity of cilia function to flow is correlated to cilia length. Cells with abnormal cilia length or function can lead to a host of diseases that are coll...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • The Journal of Cell Biology

دوره 39  شماره 

صفحات  -

تاریخ انتشار 1963