Growth and physiology of rickettsiae.

Weiss, Emilio

doi:10.1128/mmbr.37.3.259-283.1973

Cited by 59 publications

(45 citation statements)

References 85 publications

(153 reference statements)

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“…typical Gram-negative bacterial morphology (Weiss, 1973;Winkler, 1990). The rickettsiae grow with a generation time of about 10h directly In the cytoplasm of eukaryotic host cells (Wisseman et ai, 1976;Turco and Winkler, 1989).…”

Section: Introductionmentioning

confidence: 99%

The concentrations of stable RNA and ribosomes in Rickettsia prowazekii

Pang

Winkler

1994

Molecular Microbiology

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The obligate intracellular parasite, Rickettsia prowazekii, is a slow-growing bacterium with a doubling time of about 10 h. In the present study, DNA and RNA were obtained from the rickettsiae by two independent methods, i.e. simultaneous isolation of DNA and RNA from the same sample by phenol:chloroform extraction and CsCI gradient centrifugation. In addition, ribosomal RNA was obtained by sedimentation of partially purified ribosomes from the rickettsiae. The results demonstrated that, after correction for the cell volumes, the concentrations of stable RNA and ribosomes in R. prowazekii, a slow-growing organism, were about 62 fg micron-3 and 17,000 per micron3, respectively, which were very similar (66 fg micron-3 and 21,000 per micron3) to those in Escherichia coli with a generation time of 40 min. However, on a per cell basis, R. prowazekii had 5.6 fg of RNA and 1500 ribosomes per cell, which was only about 8% of the amount of both stable RNA (71.2 fg) and ribosomes (24,000) per cell as was found in E. coli. These results indicated that R. prowazekii possesses a ribosome concentration greater than might have been predicted from its slow growth rate. This high concentration of ribosomes could be due to a large population of nonfunctioning ribosomes, a low efficiency of amino acid production, or a high rate of protein turnover. However, this study also demonstrated that the rickettsiae have very limited protein turnover. Knowledge of the kinetics and control mechanisms for protein synthesis in R. prowazekii remains to be established to determine the logic of the extra rickettsial ribosomes.

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Section: Introductionmentioning

confidence: 99%

The concentrations of stable RNA and ribosomes in Rickettsia prowazekii

Pang

Winkler

1994

Molecular Microbiology

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“…Coxiella (C.) burnetii, the causative agent of the zoonosis Q fever (DAVIS and COX, 1938) infects ticks, rodents, wild and domestic animals and man (MARRIE, 1990;WEISS, 1973). Compared t o other members of the family Rickettsiaceae the organism displays an unusually high resistance against environmental conditions.…”

Section: Introductionmentioning

confidence: 99%

A Sporulation Gene in Coxiella burnetii?

Oswald

Thiele

1993

Journal of Veterinary Medicine, Series B

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Summary During a search for conserved target sequences on the genome of Coxiella burnetii for a diagnostic PCR a NotI/EcoRV DNA fragment was cloned and sequenced from the isolate “Nine Mile”, Phase I (sequence data are registered under accession number X70045 in data bases EMBL, GENE‐BANK and DDBJ). On this fragment we have found a sequence of 1741 base pairs which showed an exceptionally high homology (60 % on the nucleic acid level and 49.6 % on the amino acid level) to the sporulation gene “spoIIIE” of the grampositive bacterium Bacillus subtilis. This is first evidence of the molecular basis for formation of spores in Coxiella burnetii which has been postulated in the literature by electron microscopic investigations.

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“…It is an obligate intracellular parasite that invades endothelial cells and macrophages, replicating near the nucleus of host cells (6). O. tsutsugamushi is a fragile bacterium, loosing its viability rapidly after release into the extracellular environment (18).…”

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confidence: 99%

“…The most frequently used method is the Giem-sa-stained bacterial counts following 3 or 4 days of antibiotic treatment (6). While this method requires few special reagents, it is time-consuming and complicated owing to difficulties in quantifying bacterial particles microscopically with its tendency to form microcolonies in cells (18).…”

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confidence: 99%

Application of Monoclonal Antibody, Specific for Intracellular Orientia tsutsugamushi, to Immunofluorescent Antibody Test for Determining Antibiotic Susceptibility

Mee-Kyung

Odgerel

Kim

et al. 2004

Microbiology and Immunology

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Abstract:The simple quantification of viable intracellular bacteria is important for the study of an obligate intracellular bacterium, Orientia tsutsugamushi. We applied a novel monoclonal antibody (M686-13) -specific for intracellular Orientia-to an immunofluorescent antibody (IFA) test for determining antibiotic susceptibility of O. tsutsugamushi. M686-13 did not react with Orientia that was inhibited by doxycycline, although bacterial particles still remained in the cells. This preferential staining of proliferating bacteria made the IFA test rapid and precise. Using this method, we could successfully measure the minimal inhibitory concentration (MIC) of a Korean strain of O. tsutsugamushi to doxycycline and clindamycin. This method may be used in other procedures to evaluate the growth of Orientia.

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Growth and physiology of rickettsiae.

Cited by 59 publications

References 85 publications

The concentrations of stable RNA and ribosomes in Rickettsia prowazekii

The concentrations of stable RNA and ribosomes in Rickettsia prowazekii

A Sporulation Gene in Coxiella burnetii?

Application of Monoclonal Antibody, Specific for Intracellular Orientia tsutsugamushi, to Immunofluorescent Antibody Test for Determining Antibiotic Susceptibility

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