A New Type of Polar Monotrichous Flagellation

Abstract

SUMMARY : An organism with a new type of polar monotrichous flagella is described. The flagella have a very short wavelength which is very characteristic. The organism liquefies gelatin and oxidizes ethanol to acid. All other common differential tests were negative. The name Pseudornonas diminuta n.sp. is suggested.The curvature of bacterial flagella is quite constant and sufficiently characteristic to be of considerable taxonomic importance. The usual wavelength of the flagella of such polar monotrichous bacteria as Pseudomonas aeruginosa and Vibrio comma is in the neighbourhood of 2p. In a large collection of cultures of Gram-negative bacteria submitted to the authors for flagellar study by Robert Keller of the Museum of Natural History of Philadelphia were found three cultures which showed very unusual monotrichous flagella, having a wavelength of only slightly over 0 . 6~. The cultures originated from fresh-water streams. Morphologically and physiologically the three cultures were identical and one description will apply to all. MORPHOLOGY OF ORGANISMThe organism is a small Gram-negative rod averaging 0-5 by 1 . 0~ in the usual peptone media. Capsule or spore formation was not demonstrable. It is actively motile with predominantly a single polar flagellum. A flagellum at each pole is fairly common in young cultures, and occasionally two flagella may be found on one pole. The flagella have two unusual characteristics: (1) Many of the individuals show the flagellum originating from the periphery of the pole rather than from the centre of the pole, the latter being the more usual origin with monotrichous bacteria. (2) The flagellar curvature is most unusual with an average wavelength of only 0 . 6 2 ,~~ and an average wave amplitude of 0.32,~. The standard deviation of the wavelengths from the mean, based on measurements of twenty-five flagella, is 0 . 1 2~ and the standard error of the mean wavelength is 0.024,~. In Fig. 1 is illustrated the flagellar morphology of the organism. The insert in the lower right corner shows the flagellar morphology of a typical strain of Pseudomonas aeruginosa.The wavelength of the flagella of the strain of Ps. aeruginosa pictured is most common with monotrichous types of bacteria and averages slightly over 2 ,~. This statement is based on the study of over 100 strains, representing many, but mainly unclassified, species. Among the named species of Pseudomoms studied may be mentioned Ps. stutxeri, Ps. Puorescens, Ps. saccharophila, Ps. mucidolens, and the polar multitrichous Ps. marginalis. The flagella were stained according to the method of Leifson (1951).

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

“…diminuta. This latter appears a striking difference, but the present writer feels that the creation of this new species of Pseudomonas by Leifson & Hugh (1954) on the sole basis of the unusual flagella wavelength may be questioned. Indeed the allocation of Leifson & Hugh's organism to the genus Pseudomonas may be queried because of lack of pigment, no acid production from glucose, rapid production of acid (which acid?)…”

Phenylobacterium immobile gen. nov., sp. nov., a Gram-Negative Bacterium That Degrades the Herbicide Chloridazon

“…Pseudomonas diminuta was originally defined by its unusual flagellar structure. This organism is monotrichous, and the flagellum is very small and tightly coiled (27). Investigations of Pseudomonas diminirta and Pseiidomonas vesicularis strains showed that these organisms utilize a quite limited range of carbon sources and require pantothenate, biotin, and cyanocobalamin as growth factors (2).…”

Isolation of Alginate-producing Mutants of Pseudomonas fluorescens, Pseudomonas putida and Pseudomonas mendocina

“…The temperature employed for growth was 30 OC and Pseudomonas Isolation Agar (Difco) was Leifson & Hugh (1954) NCIB 1054:l Strain CH-50 Palleroni et al (1970) replaced by medium A for growth of strains NCIB 10541, NCIB 9040, NCIB 9946, NCIB 8893 and NCIB 9393.…”