Motility

Bacterial motion is generally associated with the presence of organs of locomotion known as flagella (singular, flagellum). They were first observed in stained preparations by Cohn. The presence of flagella does not mean necessarily that the organisms are always motile, but it indicates a potential power to move. 

Independent bacterial motion is a true movement of translation and must be distinguished from the quivering or back-and-forth motion exhibited by very small particles suspended in a liquid. This latter type of motion is called Brownian movement and is caused by the bombardment of the bacteria by the molecules of the suspending fluid. 

Flagella are very delicate organs and easily detached from the 

Some believe flagella originate from the cell wall others believe they traverse the cell wall into the protoplasm. 

Flagella differ chemically both from the cell wall and the protoplasm. 

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Small, 1989] Small, J. V. Microfilament-based motility in non-muscle cells. Curr. Opinion Cell Biol. 1 (1989) 75-79... 

Theriot et al., 1992] Theriot, J. A., Mitchison, T. J., Tilney, L. G., and Portnoi, D. A. The rate of actin-based motility of intracellular Listeria monocytogenes equals the rate of actin polymerization. Nature. 357 (1992) 257-260... 

Diphenoxylate Hydrochloride. l-(3-Cyano-3,3-diphenylpropyl)-4-phenyl-4-piperidinecarboxyhc acidmonohydrochlorhydrate [3810-80-8] (Lomotil) (13) is a white, odorless, crystalline powder that melts at 220—226°C. It is soluble ia methanol, spariagly soluble ia ethanol and acetone, slightly soluble ia water and isopropyl alcohol, freely soluble ia chloroform, and practically iasoluble ia ether and hexane. The method of preparation for diphenoxylate hydrochloride is available (11). Diphenoxylate hydrochloride [3810-80-8] (13) is an antidiarrheal that acts through an opiate receptor. It has effects both on propulsive motility and intestinal secretion. Commercial forms are mixed with atropiae to discourage abuse. 

Biologica.1 Activities a.ndAna.logues, The many pharmacological actions of neurotensin include hypotension, increased vascular permeabihty, hyperglycemia, increased intestinal motility, and inhibition of gastric acid secretion (120). In the brain, it produces analgesia at remarkably low doses (121). 

Proteins can be broadly classified into fibrous and globular. Many fibrous proteins serve a stmctural role (11). CC-Keratin has been described. Fibroin, the primary protein in silk, has -sheets packed one on top of another. CoUagen, found in connective tissue, has a triple-hehcal stmcture. Other fibrous proteins have a motile function. Skeletal muscle fibers are made up of thick filaments consisting of the protein myosin, and thin filaments consisting of actin, troponin, and tropomyosin. Muscle contraction is achieved when these filaments sHde past each other. Microtubules and flagellin are proteins responsible for the motion of ciUa and bacterial dageUa. 

They also are important portals for systemic therapy. However, many variables can influence dmg dissolution and absorption ia these areas, including rate of gastric emptying, intestinal motility, mass and pH of intestinal contents, and condition of the absorbiag surfaces (15—17). These variables, ia turn, can be affected by the patient s disease, posture, and eating habits, and even by such aspects of the treatment as the timing of doses (11). 

Alpha helices are sufficiently versatile to produce many very different classes of structures. In membrane-bound proteins, the regions inside the membranes are frequently a helices whose surfaces are covered by hydrophobic side chains suitable for the hydrophobic environment inside the membranes. Membrane-bound proteins are described in Chapter 12. Alpha helices are also frequently used to produce structural and motile proteins with various different properties and functions. These can be typical fibrous proteins such as keratin, which is present in skin, hair, and feathers, or parts of the cellular machinery such as fibrinogen or the muscle proteins myosin and dystrophin. These a-helical proteins will be discussed in Chapter 14. 

Motile Motile organisms exhibit or are capable of movement. 

Protozoa A group of motile microscopic animals (usually single-celled and aerobic) that sometimes cluster into colonies and often consume bacteria as an energy source. 

Cilia Hair-like motile extensions of a cell wall. Airway cells use cilia to pro-... 

Contractile and motile proteins Actin Myosin Tubulin Dyne in Kinesin... 

Certain proteins endow cells with unique capabilities for movement. Cell division, muscle contraction, and cell motility represent some of the ways in which cells execute motion. The contractile and motile proteins underlying these motions share a common property they are filamentous or polymerize to form filaments. Examples include actin and myosin, the filamentous proteins forming the contractile systems of cells, and tubulin, the major component of microtubules (the filaments involved in the mitotic spindle of cell division as well as in flagella and cilia). Another class of proteins involved in movement includes dynein and kinesin, so-called motor proteins that drive the movement of vesicles, granules, and organelles along microtubules serving as established cytoskeletal tracks. ... 

Blanchard, A., Ohanian, V., and Critchley, D., 1989. The. structure and fnnction of a-3.c inin. Journal of Muscle Research and Cell Motility 10 280-289. 

A not uncommon side effect observed with morphine and some of the other narcotic analgesics is constipation due to decreased motility of the gastrointestinal tract. It proved possible to so modify pethidine as to retain the side effect at the expense of analgesic activity. Relief of diarrhea, it will be realized, is a far from trivial indication. Alkylation of the anion from diphenylacetonitrile (95) with ethylene dibromide gives the intermediate, 96. Alkylation of normeperidine (81) with that halide... 

Induces dyskinesia/vasodilatation, schizophrenia/4- coordination Vaso constriction/cell proliferation/aldosterone secretion Vaso constriction/cell proliferation/bronchoconstriction 4-memory, sedation/vasodilatation/4 GI motility A blood pressure/4- GI secretion Vagal effects/A blood pressure/tachycardia... 

Autonomic functions/palpitations, nausea, sweating 4- gut motility, gas trie/tremor, ganglionic function... 

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