Further Advances in the Study of Microbic Dissociation

Hadley, Philip B.

doi:10.1093/infdis/60.2.129

Cited by 44 publications

(15 citation statements)

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“…in diameter on YE agar, but there were opaque, off-white colonies occurring at low frequency. Variation in the colonial morphology of Pseudomonas aeruginosa has long been known (Hadley, 1937) and has been studied by several investigators (Gaby, 1946;Gaby & Free, 1953; Williamson, 1956). The observations made in the present work confirm the results of other investigators that colonies on agar may be exclusively of one type or a mixture of both types.…”

Section: Resultsmentioning

confidence: 99%

A Study of Features used in the Diagnosis of Pseudomonas aeruginosa

Colwell

1964

Journal of General Microbiology

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SUMMARYThirty-three strains of Pseudomoizas aeruginosa, previously described as a species group by a quantitative study, were subjected to an extended schedule of tests used in bacterial classification and identification. Adansonian analysis by electronic computer confirmed previous results, indicating that the 33 strains should be treated as a species group. The 172 features coded for each strain were analysed by computer, yielding a ' probability of occurrence ' of each feature within the species, P. aeruginosa.This output was then used to select features appropriate for diagnostic purposes. From the analyses it was also possible to measure the sensitivity of several methods for determining the presence or absence of characteristics such as pigment production and oxidation of gluconate to ketogluconate. The general applicability of the use of the computer to cooperative pooling of data by bacteriologists is discussed.

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Section: Resultsmentioning

confidence: 99%

A Study of Features used in the Diagnosis of Pseudomonas aeruginosa

Colwell

1964

Journal of General Microbiology

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“…The occurrence of life cycles in members of the Eubacteriales has been proposed from time to time (Lohnis, 1921;Hadley, 1937) but, with the exception of the spore-bacillus-spore cycle of the family Bacillaceae, is not generally accepted by bacteriologists. In the last 15 years, however, studies of L-forms by Klieneberger-Nobel(l949, 1951 a, b) (1954), but these authors doubted whether this process is a sexual one.…”

Section: Discussionmentioning

confidence: 99%

Microcyst Formation and Germination in Spirillum lunatum

Williams

Rittenberg

1956

Journal of General Microbiology

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SUMMARY: Spirillum lunatum has been shown to possess a life cycle in which there is an alternation between a vegetative and a microcyst stage. Microcyst formation may occur from the spiral vegetative cell by: (1) fusion of two entwined organisms to form one or more microcysts ; (2) the production of a protuberance a t some point along the organism into which the entire organism is gradually absorbed; (3) the gradual shortening and rounding of the organism to form an oval to spherical body. Microcyst formation begins, in a typical broth culture, a t c. 24 hr. after inoculation and the majority of the organisms are in the microcyst stage after a 4-day incubation period. When microcysts from an old culture are inoculated into fresh media, they germinate to form the spiral vegetative organism. Germination occurs by either unipolar or bipolar emergence of the germ tube.During a taxonomic study of the genus SpiriZZurn Ehrenberg (Williams, 1952), it was found that three species of the marine spirilla and two of the freshwater species exhibited morphological changes during the growth of the cultures. Young cultures, which consisted entirely of spiral organisms, gradually changed until only oval or spherical bodies (0*8-5*0p. in diameter, depending on the species) were found in old cultures. When these bodies were inoculated into fresh media, the normal spiral organism germinated from them. Since the entire organism is involved in the formation of these oval to spherical bodies, in a manner similar to the formation of the microcysts of the Sporocytophuga (Stanier, 1942; Grace, 1951), these bodies have been called ' microcysts '. Because of its relatively large size, S. Zunaturn was chosen as the experimental organism. The morphological changes which occur in this species are similar, although not identical, to those occurring in the other two marine spirilla and in the two freshwater species. METHODSThe spirillum was grown in sea-water nutrient broth of the following composition: peptone, 5.0 g.; beef extract, 3.0 g.; yeast autolysate, 3.0 g.; and sea water, 1000 ml. Broth tubes were inoculated with old cultures, ranging in age from 2 to 6 weeks, and incubated at 30". Organisms removed from the broth cultures at appropriate times between 8 and 72 hr. were used for microcultures. Cultures less than 24 hr. old were centrifuged and the harvested organisms re-suspended in a small amount of sterile sea water. Cultures older than 24 hr.

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“…Daneben treten jedoch auch andere Veranderungen auf, die beispielsweise die Antigenstruktur, das biochemische Verhalten und die Pathogenitat betreffen konnen. Die Eigenschaften der durch Dissoziation entstandenen Varianten werden auf die nachfolgenden Generationen vererbt (Hadley, 1937und Lamanna etaL, 1973. Das spontane Auftreten der nicht iridisierenden Variante (V n j) in der iridisierenden (VO Ausgangspopulation des//.…”

Section: Vioo83unclassified

Beitrag zur differenzierung von haemophilus‐ stämmen aus hühnern IV. Mitteilung: Untersuchungen über die dissoziation von haemophilus paragallinarum

Hinz

1976

Avian Pathology

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Bacteria of 2 phenotypic forms of one strain of Haemophilus paragallinarum were morphologically, culturally, biochemically and serologically investigated. On transparent solid media bacteria of the M variant (mucoid) were capsulated and showed iridescence in oblique transmitted light throughout the first 8-14 hours of incubation. Iridescence disappeared completely after 36 hours incubation. Bacteria of this variant formed stable homogeneous suspensions in 0.15 M NaCl and an homogeneous cloudiness after growth in liquid media. A type specific soluble substance was found in fluid culture filtrates and in bacterial washings using the indirect haemagglutination test. Bacteria of the R variant (rough) derived by dissociation of iridescent colonies were not capsulated and showed no iridescence throughout 8-14 hours incubation (minus variant). This bacteria showed spontaneous agglutination in 0.15 M NaCl and a granular growth in liquid media. There were no biochemical differences between M and R variant. A type specific substance was not found in the R bacteria using the indirect haemagglutination test. In the plate agglutination test no serological reaction between anti-K-sera and M antigen were observed. R to M variation occurred in SPF chickens following intranasal inoculation of organisms of R cultures grown for 6 or 20 passages on solid medium.

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Further Advances in the Study of Microbic Dissociation

Cited by 44 publications

References 1 publication

A Study of Features used in the Diagnosis of Pseudomonas aeruginosa

A Study of Features used in the Diagnosis of Pseudomonas aeruginosa

Microcyst Formation and Germination in Spirillum lunatum

Beitrag zur differenzierung von haemophilus‐ stämmen aus hühnern IV. Mitteilung: Untersuchungen über die dissoziation von haemophilus paragallinarum

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