Shape and motility of bacteria

Abstract

PLATES XLIV-XLIX)" Thus once again we meet, in these lower forms, the spiral organisation which is so common a feature in plants. The conclusion is unavoidable that this prevalence of spiral structure reflects some underlying vital principle that is common to the whole of the plant kingdom " (Astbury and Preston, 1940). MANY kinds of bacteria, usually described as rods, are helices or " spirals ", and the appendages of such bacteria, usually called flagella, are a result of motility and not motile organs. Most of the present work on this subject was done on B. typhosus, but observations on B. proteus, B. megatherium, B. cereus, B. subtilis, B. jluorescens and others indicated that this new conception of shape and motility applies widely. For the purposes of this paper " bacteria " means most of the I ' Eubacteriales ". Bacterial flagella : stained preparationsThe invisibility of flagella with ordinary microscopy has led to the invention of numerous staining methods, satisfactory to their authors, but usually a failure in other hands. Often mucous threads attached to bacteria have been stained and regarded as flagella. Instances are the denial by van Niel (1923-24) of Ellis's claim (1902, that certain sarcinE possessed flagella, and the supposed flagellation of B. tulareme, refuted by Hesselbrock and Foshay (1945). Zettnow, inventor of a much used staining method (1899), admitted later (191%) that he could not always differentiate between " mucous threads " and flagella, especially when mucous threads showed a wavy appearance, and added that such structures should only be regarded as flagella when motility had fist been established ! Hinterberger (1921) similarly warned against confusing what he called " Myzele" with true flagella, but his basis for JOUEN. OF PA%E.-VOL. LVIU 325 Z * JOURB. OF PATH.-VOL. LVIIl

Colon-Targeted Oral Drug Delivery Systems: Design Trends and Approaches

“…On the other hand, the addition of β-mannase significantly enhanced BSA release, with 95% of the BSA released after 8 h in the presence of this enzyme, and only 60% was released in its absence. Azo-aromatic polymers, which are among the most researched groups of compounds used as prodrugs, are susceptible to degradation by azoreductases (18,19). Therefore, they can be used to coat the drug molecules such as peptides to protect them from degradation by peptidases in the stomach and small intestine while still permitting drug release in the colon.…”

“…Viscosity also influences the penetration of the drug into the disease-causing bacteria in the colon. The mobility of bacteria in the colon has been shown to be dependent on the viscosity of colonic contents (18).…”

The Cytology of Pseudomonas spp. as Revealed by a Silver-Plating Staining Method

“…When it was not possible to focus flagella through a capsule, they could be distinguished from fine strands of slime or capsular material which were frequently seen (apparently drawn out from any zone of the capsule) by: ( a ) the uniform diameter; ( b ) the regular spiral shape (usually); ( c ) the darker colour; ( d ) the polar position. The slime strands are not considered to lend any support to Pijper's (1946) theory of bacterial locomotion.…”

Real-Time Imaging of Fluorescent Flagellar Filaments

“…From 1931 onwards, Pijper used the sun as a light source, equipping his microscope with a heliostat (30). In 1946, he decided that flagella were artifacts of locomotion (31). This led to a lively debate (36).…”