The Biology of Rickettsiae

Weiss, Emilio

doi:10.1146/annurev.mi.36.100182.002021

Cited by 96 publications

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“…Taken together, these findings indicate that C. psittaci AA Mp lacks the ability to de novo synthesize pyrimidines and as a result must salvage pyrimidines from the host. Rickettsia, another obligate intracellular bacterium, also lacks the capacity to de novo synthesize or salvage pyrimidine ribonucleotides (36,37). In contrast, the vast majority of free-living bacteria can carry out de novo pyrimidine synthesis, an exception being the mycoplasmas (19).…”

Section: Discussionmentioning

confidence: 99%

Pyrimidine metabolism by intracellular Chlamydia psittaci

McClarty

Qin

1993

J Bacteriol

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Pyrimidine metabolism was studied in the obligate intracellular bacterium Chlamydia psittaci AA Mp in the wild type and a variety of mutant host cell lines with well-defined mutations affecting pyrimidine metabolism.C. psittaci AA Mp cannot synthesize pyrimidines de novo, as assessed by its inability to incorporate aspartic acid into nucleic acid pyrimidines. In addition, the parasite cannot take UTP, CTP, or dCTP from the host cell, nor can it salvage exogenously supplied uridine, cytidine, or deoxycytidine. The (7,20). The species C. trachomatis and C pneumoniae are primarily human pathogens (6, 26).In contrast, C. psittaci has been isolated from humans and a very large number of avian and mammalian species, in which it produces a variety of diseases (26,28). Despite the clinical and economic importance of chlamydiae, many aspects of their basic biology have not been studied and the metabolic relationships that exist between the parasites and their hosts remain largely unknown (20). This is, in part, due to the fact that axenic growth of chlamydiae has not been realized. In addition, host-free chlamydiae display limited metabolic activity (12,20).Our laboratory is particularly interested in nucleotide metabolism in chlamydiae. To study nucleotide metabolism in C. trachomatis, we have employed an in situ approach with well-defined mutant host cell lines and several different radiolabelled nucleic acid precursors (4,5,18,24,29,30). The results generated indicate that C. trachomatis (i) cannot de novo synthesize purines or pyrimidines, (ii) lacks the ability to salvage preformed purine or pyrimidine nucleobases and (deoxy)nucleosides, (iii) can obtain all four ribonucleotides directly from the host cell, (iv) encodes a ribonucleotide reductase and thymidylate synthase for synthesizing deoxyribonucleotides from host-derived ribonucle-* Corresponding author. t Present address:

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Section: Discussionmentioning

confidence: 99%

Pyrimidine metabolism by intracellular Chlamydia psittaci

McClarty

Qin

1993

J Bacteriol

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“…A second hypothesis could be: the number of bacteria is the same in TF and ARF neo-females but their transmission rates to progenies are different. The host control could then act on endocytosis, which is the principal way involved in Rickettsial entry into host cells (Weiss, 1982;Tamura, 1988). Finally, the genetic control could act not on the bacteria themselves but rather prevent them from expressing their feminizing effect.…”

Section: Discussionmentioning

confidence: 99%

“…This bacteria recalls the Rickettsiales (Weiss, 1982), and more particularly the Wolbachia sp. observed in different species of mosquito (Irvin-Bell, 1974;Larsson, 1983).…”

Section: Introductionmentioning

confidence: 99%

Genetic control of the vertical transmission of a cytoplasmic sex factor in Armadillidium vulgare Latr. (Crustacea, Oniscidea)

Rigaud

Juchault

1992

Heredity

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In Armadillidium vulgare, sexdetermination may be under the control of a maternally transmitted endosymbiotic bacteria (F), which reverses genetic males (ZZ) into functional neo-females (ZZ + F). These neo-females generally produce highly female-biased progenies (thelygenous progenies = TF) but a few of them produce highly male-biased progenies (arrhenogenous progenies = ARF). These TF and ARE traits are selected, and the inoculation of F bacteria in different categories of females shows that these traits are genetically controlled by the host and do not depend on different bacterial strains. By pairing males from the ARE strain with genetic females (WZ), it can be seen that the ARF trait is unrelated to the effect of an autosomal masculinizing gene (M). In fact, the ARE trait appears to be under the control of a polygenic system, the genes influencing the sex ratio indirectly via their effects on the cytoplasmic factor (resistance genes).

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“…Its exploitation of this environment is reflected in a variety of novel features, most notably the existence of an ADP-ATP transport system that permits the rickettsiae to accumulate ATP directly from the cytoplasm of the host cell (44). However, the rickettsiae are not strict energy parasites and can generate their own ATP via the tricarboxylic acid cycle and oxidative phosphorylation (39). This ability is probably necessary for cell viability during periods when the host cell ATP reserves are depleted or during transit of the bacterium to a new host cell.…”

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confidence: 99%

Nucleotide sequence of the Rickettsia prowazekii citrate synthase gene

Wood¹,

Williamson²,

Winkler³

et al. 1987

J Bacteriol

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The Rickettsia prowazekii citrate synthase (gitA) gene, previously cloned in Escherichia coli, was localized to a 2.0-kilobase chromosomnal fragment. DNA sequence analysis of a portion of this fragment revealed an open reading frame of 1,308 base pafrs that encodes a protein of 435 amino acids with a molecular weight of 49,171. This translation product is comparable in size to both the E. coli Snd pig heart citrate synthase monomers and to the protein synthesized in E. coli minicells containing the rickettsial gene. Comparisons between the deduced amino acid sequence of R. prowazekii citrate synthase and those of the E. coli and pig heart enzymes revealed extensive homology (59%) between the two bacterial proteins. In contrast, only 20% of the rickettsial enzyme residues were shared with the functionally similar pig heart enzyine residUes. Upstream from the open reading frame and in close proximity to one anothet, sequences with homology to E. coli consensus sequences for RNA polymerase and ribosome binding were identified. S1 nuclease mapping experiments demobstrated that the start of transcription for this gene in E. coli was located in the upstream region. Codon usage in the rickettsial git4 gene was found to be very biased and differed from the pattern observed in E. coli. Adenine and uracil were used preferentially in the third base position of rickettsial codons.Rickettsia prowazekii is an obligate intracellular parasitic bacterium that multiplies within the cytoplasm of its eucaryotic host cell rather than within a phagosome or phagolysosome. Its exploitation of this environment is reflected in a variety of novel features, most notably the existence of an ADP-ATP transport system that permits the rickettsiae to accumulate ATP directly from the cytoplasm of the host cell (44). However, the rickettsiae are not strict energy parasites and can generate their own ATP via the tricarboxylic acid cycle and oxidative phosphorylation (39). This ability is probably necessary for cell viability during periods when the host cell ATP reserves are depleted or during transit of the bacterium to a new host cell. Central to the regulation of the tricarboxylic acid cycle is the enzyme citrate synthase.Citrate synthase, the first enzyme of the tricarboxylic acid cycle, has been extensively studied in a variety of procaryotic and. eucaryotic cells (30,, 41, 43). These studies have identified two main types of citrate synthase: a "small" type (molecular weight, -106,000) found in eucaryotic cells and gram-positive bacteria and a "large" type (molecular weight, -250,000) found exclusively in gram-negative bacteria. The small enzyme is a dimer composed of two identical subunits, while the large enzyme is a multimer composed of four to six identical subunits. The two types of enzyme also differ in their sensitivity to certain effectors. The small enzyme is senlsitive in vitro to inhibition by ATP but not by at-ketoglutarate or NADH, while the large enzyme is sensitive in vitro to inhibition by a-ketoglutarate and NADH but not by ...

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The Biology of Rickettsiae

Cited by 96 publications

References 0 publications

Pyrimidine metabolism by intracellular Chlamydia psittaci

Pyrimidine metabolism by intracellular Chlamydia psittaci

Genetic control of the vertical transmission of a cytoplasmic sex factor in Armadillidium vulgare Latr. (Crustacea, Oniscidea)

Nucleotide sequence of the Rickettsia prowazekii citrate synthase gene

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