Copy number of the 16S rRNA gene in Rickettsia prowazekii

Pang, Huiling; Winkler, Herbert H.

doi:10.1128/jb.175.12.3893-3896.1993

Cited by 31 publications

(17 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Single-band patterns consistent with the hypothesis that there are single copies of the 16s rRNA gene in R. bellii, R. prowazekii, and the SFG species Rickettsia montana were aIso obtained when genomic DNA restricted by either SphI or EcoRI was probed by using labeled R. bellii 16s rRNA. Results obtained previously for R. prowazekii also indicated that this organism has a single copy of the 16s rRNA (21).…”

Section: Resultsmentioning

confidence: 52%

Ancestral Divergence of Rickettsia bellii from the Spotted Fever and Typhus Groups of Rickettsia and Antiquity of the Genus Rickettsia

Stothard

Clark

Fuerst

1994

International Journal of Systematic Bacteriology

View full text Add to dashboard Cite

The eubacterial genus Rickettsia belongs to the cu subgroup of the phylum Proteobacteriu. This genus is usually divided into three biotypes on the basis of vector host and antigenic cross-reactivity characteristics. However, the species Rickettsia bellii does not fit into this classification scheme; this organism has characteristics common to both the spotted fever group and the typhus group biotypes and also exhibits some unique features. Sequences of the 16s rRNA and 23s rRNA genes from Rickettsia rickettsii (spotted fever group), Rickettsia prowazekii (typhus group), and R. bellii were studied to determine the position of R. bellii in the rickettsia1 classification scheme. The 23s rRNA gene sequences described in this paper are the first 23s rRNA sequences reported for any member of the Rickettsiuceue. The 23s rRNA gene contains substantially more phylogenetic information than is contained in the 16s rRNA sequences, and the 23s rRNA gene sequence has diverged about 1.9 times faster in the three Rickettsia species which we studied. Taken together, the molecular data obtained from the two genes indicate that R. bellii is not a member of either the spotted fever group or the typhus group; rather, this organism appears to be the product of a divergence which predates the separation of the genus into the spotted fever group and the typhus group. Consequently, different combinations of the ancestral characteristics retained by R. bellii have been retained in the more derived lineages of the genus. A comparison of the 16s rRNA and 23s rRNA gene sequences of Rickettsia strains with other proteobacterial sequences confirmed that the genus Rickettsia is a unique deeply branching member of the cu subgroup of the Proteobacteria and that the Rickettsia species form a monophyletic cluster. While divergence of the contemporary members of the genus Rickettsia occurred recently, the unique evolutionary line represented by this genus appears to be very old.Rickettsia strains are small, gram-negative bacteria that are intimately associated with eukaryotic cells and are members of a diverse family, the Rickettsiaceae, which also includes other intracellular organisms, including the genera Ehrlichia, Wolbachia, Anaplasma, and Cowdria (4,36). Rickettsiae have natural arthropod hosts (either ticks, mites, or insects) and can be pathogenic for humans and other vertebrates. The obligately intracellular lifestyle and fastidious nature of these organisms have made them difficult to study. A number of genotypic and phenotypic characteristics indicate that the Rickettsia species are closely related, and this genus is now recognized as the sole member of a branch of the cx subgroup Proteobacteriu (8) on the basis of 16s rRNA cataloging and partial 16s rRNA gene sequence data (34).The genus Rickettsia is divided into three biotypes on the basis of immunological cross-reactivity and ecological characteristics (36). Rickettsia species are placed into the spotted fever group (SFG), the typhus group (TG), or the scrub typhus group on the basis...

show abstract

Section: Resultsmentioning

confidence: 52%

Ancestral Divergence of Rickettsia bellii from the Spotted Fever and Typhus Groups of Rickettsia and Antiquity of the Genus Rickettsia

Stothard

Clark

Fuerst

1994

International Journal of Systematic Bacteriology

View full text Add to dashboard Cite

show abstract

“…Neutralized genes are subject to mutational degradation (101). When genes required for the free-living mode are forfeited, the facultative symbiont has evolved into an obligate symbiont or an obligate parasite, with a coding capacity that can be extremely limited (70,71,72,94,147,170,172). For example, the obligate parasites of the genus Rickettsia, like mitochondria, have virtually no genes for amino acid or nucleoside biosynthesis, but their facultative parasitic relatives, the Bartonella spp., are fully able to produce these intermediates in their free-living mode (20; Andersson et al, unpublished data).…”

Section: Genome Degradationmentioning

confidence: 99%

Origin and Evolution of the Mitochondrial Proteome

Kurland

Andersson

2000

Microbiol Mol Biol Rev

363

272

View full text Add to dashboard Cite

SUMMARY The endosymbiotic theory for the origin of mitochondria requires substantial modification. The three identifiable ancestral sources to the proteome of mitochondria are proteins descended from the ancestral α-proteobacteria symbiont, proteins with no homology to bacterial orthologs, and diverse proteins with bacterial affinities not derived from α-proteobacteria. Random mutations in the form of deletions large and small seem to have eliminated nonessential genes from the endosymbiont-mitochondrial genome lineages. This process, together with the transfer of genes from the endosymbiont-mitochondrial genome to nuclei, has led to a marked reduction in the size of mitochondrial genomes. All proteins of bacterial descent that are encoded by nuclear genes were probably transferred by the same mechanism, involving the disintegration of mitochondria or bacteria by the intracellular membranous vacuoles of cells to release nucleic acid fragments that transform the nuclear genome. This ongoing process has intermittently introduced bacterial genes to nuclear genomes. The genomes of the last common ancestor of all organisms, in particular of mitochondria, encoded cytochrome oxidase homologues. There are no phylogenetic indications either in the mitochondrial proteome or in the nuclear genomes that the initial or subsequent function of the ancestor to the mitochondria was anaerobic. In contrast, there are indications that relatively advanced eukaryotes adapted to anaerobiosis by dismantling their mitochondria and refitting them as hydrogenosomes. Accordingly, a continuous history of aerobic respiration seems to have been the fate of most mitochondrial lineages. The initial phases of this history may have involved aerobic respiration by the symbiont functioning as a scavenger of toxic oxygen. The transition to mitochondria capable of active ATP export to the host cell seems to have required recruitment of eukaryotic ATP transport proteins from the nucleus. The identity of the ancestral host of the α-proteobacterial endosymbiont is unclear, but there is no indication that it was an autotroph. There are no indications of a specific α-proteobacterial origin to genes for glycolysis. In the absence of data to the contrary, it is assumed that the ancestral host cell was a heterotroph.

show abstract

“…5a). The sequence conservation between individual rRNA genes when multiple copies are present in the bacterial genome allows the detection of tandem genes using a combination of enzymes that do and do not cleave within the gene sequence (Pang & Winkler, 1993 BAC clones B7 (16S clone) and D3 (23S clone) were initially digested using enzymes that had a single cleavage site within the rRNA genes (EcoRI and PstI for 16S ; NcoI and HindIII for 23S). They were then digested a second time using enzymes that did not cut within the rRNA genes (BamHI, NotI, EcoRV and NdeI for 16S ; EcoRI, BamHI, NotI, EcoRV and NdeI for 23S).…”

Section: F R Rurangirwa and Othersmentioning

confidence: 99%

“…Deviations from the typical 16S-23S-5S operon structure are rare, with the exception of obligate intracellular bacteria with small ( 1n5 Mb) genomes. Alternative rRNA gene arrangements are characterized by very low copy numbers of the rRNA genes with loss of the classical operon structure (Pang & Winkler, 1993 ;Andersson et al, 1995). These atypical structures are hypothesized to have arisen from a progenitor with the classical multiple operon structure by mutation and then differential deletion of individual 16S, 23S or 5S rRNA genes (Andersson et al, 1995 ;Kurland & Andersson, 2000).…”

mentioning

confidence: 99%

Conservation of the unique rickettsial rRNA gene arrangement in Anaplasma.

Rurangirwa¹,

Brayton²,

McGuire³

et al. 2002

International Journal of Systematic and Evolutionary Microbiology

View full text Add to dashboard Cite

The organization of the rRNA genes of Anaplasma marginale, the type species of the genus Anaplasma, was identified to determine if the atypical rRNA gene arrangement identified in rickettsiae preceded divergence of the order Rickettsiales into the families Anaplasmataceae and Rickettsiaceae. The rRNA genes are encoded by two unlinked units, each present in a single copy per A. marginale genome. The 16S rRNA gene is separated from the linked 23S and 5S rRNA genes by a minimum of 100 kb. Similar to species belonging to the genus Rickettsia, the typical bacterial 16S-23S spacer region containing tRNA genes has been lost in A. marginale. In contrast, the fmt gene located upstream of the 23S rRNA gene in most Rickettsia spp. is not maintained in A. marginale, consistent with the fmt arrangement being a relatively late event in the evolution of rickettsial species.

show abstract

Copy number of the 16S rRNA gene in Rickettsia prowazekii

Cited by 31 publications

References 23 publications

Ancestral Divergence of Rickettsia bellii from the Spotted Fever and Typhus Groups of Rickettsia and Antiquity of the Genus Rickettsia

Ancestral Divergence of Rickettsia bellii from the Spotted Fever and Typhus Groups of Rickettsia and Antiquity of the Genus Rickettsia

Origin and Evolution of the Mitochondrial Proteome

Conservation of the unique rickettsial rRNA gene arrangement in Anaplasma.

Contact Info

Product

Resources

About