Scanning electron microscopic study of virulent and avirulent colonies of Neisseria gonorrhoeae

Elmros, T; Hörstedt, Per; Winblad, Bengt

doi:10.1128/iai.12.3.630-637.1975

Cited by 18 publications

(10 citation statements)

References 17 publications

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“…In the current study we used a lighting system that clearly delineated colonial morphology. The two major colonial configurations observed with this system, high domed and low convex, have also been observed in studies of various colony types of gonococci by vertical sectioning of colonies (15) and by scanning electron microscopy (5).…”

Section: Discussionsupporting

confidence: 62%

Relationship of pili to colonial morphology among pathogenic and nonpathogenic species of Neisseria

McGee¹,

Dourmashkin²,

Groß³

et al. 1977

Infect Immun

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Growth in colonies with type 1 morphology and the presence of pili are characteristics that have been associated with virulence of gonococci for humans. To determine whether the presence of pili per se might be responsible for colony type 1 morphology, the relationship ofpili to colony type was examined in various species ofNeisseria. Short pili (175 to 210 nm in length) were seen only on nonpathogenic neisseria, whereas long pili (up to 4,300 nm) were seen on organisms ofboth nonpathogenic and pathogenic species. Although long pili, similar to those found on organisms from high-domed, type 1 colonies of gonococci, were observed on organisms from high-domed, type 1 colonies of nonpathogenic Neisseria species, they were also observed on low-convex, type 4 colonies of meningococci and nonpathogenic neisseria. Among meningococci there was no difference in the morphology of colonies consisting of organisms with many long pili and colonies consisting of organisms that completely lacked pili. Thus, there was no consistent relationship of pili to colonial morphology. Unless the pili of N. gonorrhoeae are unique among Neisseria species in their influence on colonial morphology, it is likely that factors other than pili determine colony type 1 morphology of gonococci. Whether these same factors, either alone or in conjunction with pili, are also responsible for gonococcal virulence warrants further investigation.

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Section: Discussionsupporting

confidence: 62%

Relationship of pili to colonial morphology among pathogenic and nonpathogenic species of Neisseria

McGee¹,

Dourmashkin²,

Groß³

et al. 1977

Infect Immun

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“…With the CPD technique pili bundles were brighter because of the charging, covering and obscuring the clumps of gonococci on the cell surface. Elmros et al (1975) reported strand-like structures between and above the gonococcal surfaces in virulent (T1 and T2) colonies, but not in avirulent (T3 and T4) colonies. The strands had much greater diameters than individual pili and it was thought that they represented bundles of pili.…”

Section: Samples Of the Hec-1-b Cell Line Which Have Beenmentioning

confidence: 90%

Scanning electron microscopy of piliated Neisseria gonorrhoeae processed with hexamethyldisilazane

Dekker

Lammel

Brooks

1991

J. Elec. Microsc. Tech.

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Piliated Neisseria gonorrhoeae are virulent and attach readily to some human mucosal cells. The study of interactions between piliated Neisseria gonorrhoeae and surface structures of eukaryotic cells in tissue culture requires consistent high resolution imaging in scanning electron microscopy (SEM). The combination of the fixatives glutaraldehyde, osmium, tannic acid, and uranyl acetate improves preservation of pili and other delicate structures. Following the critical point drying (CPD) process, pili bundles remained intact, but charging produced image distortion in most of the specimens. The use of hexamethyldisilazane (HMDS) with air drying substantially reduced charging and image distortion. Less contrast and greater resolution of pili bundles and surface structures of bacteria or tissue culture cells were obtained at magnifications of 10,000 or higher. As an alternative to CPD, HMDS processing of cell culture monolayers was simple and was more efficient when a large number of samples was processed.

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“…Colonial morphology. The presence or absence of pili was scored by colonial morphology and confirmed by scanning electron microscopy (6,11,15,16). Colonial morphology was scored essentially by the methods of Kellogg et al (16) and Swanson (26,27).…”

Section: Methodsmentioning

confidence: 99%

Effect of colony type and pH on surface charge and hydrophobicity of Neisseria gonorrhoeae

Magnusson¹,

Kihlström²,

Norlander³

et al. 1979

Infect Immun

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The effect of colonial variation and growth at pH 7.2 or pH 6.0 on the surface properties of Neisseria gonorrhoeae was assessed by the use of two-phase partitioning and hydrophobic interaction chromatography. Cells grown at pH 7.2 tended to be both hydrophobic and to possess a slight negative charge. Growth at pH 6.0 appeared to decrease hydrophobicity and to increase the negative surface charge. Possession of a series of outer membrane proteins, termed the colony opacity-associated proteins, did not appear to significantly affect charge or hydrophobicity. Piliated cells tended to have a higher negative charge than nonpiliated variants. They also tended to be less hydrophobic at pH 7.2, but became more hydrophobic at pH 6.0. The implications of these findings are discussed. to pH 6.0 with N-2-hydroxyethylpiperazine-N'-2-eth-397 on July 16, 2020 by guest http://iai.asm.org/ Downloaded from

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Scanning electron microscopic study of virulent and avirulent colonies of Neisseria gonorrhoeae

Cited by 18 publications

References 17 publications

Relationship of pili to colonial morphology among pathogenic and nonpathogenic species of Neisseria

Relationship of pili to colonial morphology among pathogenic and nonpathogenic species of Neisseria

Scanning electron microscopy of piliated Neisseria gonorrhoeae processed with hexamethyldisilazane

Effect of colony type and pH on surface charge and hydrophobicity of Neisseria gonorrhoeae

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