Some Morphological Characteristics of Nodule Bacteria as Shown by the Electron Microscope

Biochemical and Symbiotic Properties of the Rhizobia 1

“…That the type of flagellation cannot be used as a criterion of species identification appears conclusive (84). Electron micrographs of the flagella (31,84) lend no support to the recent hypothesis of Pijper (272,273).…”

“…The thick outer slime layer surrounding the celLs has provided the major technical difficulty. Some success in its elimination is afforded by frequent transfer of cultures in Laird's medium 5, a carbohydrate free, mineral salts yeast extract medium (31,39,195).…”

Flagellation of Azotobacter

“…On the other hand, it is entirely possible that in other genera such degenerate peritrichous flagellation exists. The latter supposition is supported by a limited amount of work with the electron microscope on Rhizobium meliloti ( Barnes, and Sears, 1942) in which this organism seems to have flagella much as they appear in the ordinary flagella stain, both as to number and position.…”

Some Morphological Characteristics of Nodule Bacteria as Shown by the Electron Microscope. II

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A few species of legume nodule bacteria have been studied by means of the electron microscope in an attempt to discover distinct morphological differences within the genus (Appleman, Barnes, and Sears, 1942). It is the purpose of this paper to present a more detailed study of the morphology of the soybean and sweet clover nodule bacteria, particularly with reference to localized fat areas and nuclear contents, in which classical cytological reagents and specific chemical solvents were used.In order to show differences in cell structure under the electron microscope it is often necessary to alter the density of the cellular components so that a specific region is rendered more or less opaque than the surrounding area.

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