Rickettsiaceae

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Rickettsiaceae
Rickettsia rickettsii.jpg
Rickettsia rickettsii (red dots) in the cell of a deer tick
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Bacteria
Phylum: Pseudomonadota
Class: Alphaproteobacteria
Order: Rickettsiales
Family: Rickettsiaceae
Pinkerton 1936 (Approved Lists 1980)
Tribes and genera
  • "Candidatus Arcanobacter" Martijn et al. 2015
  • "Candidatus Cryptoprodota" corrig. Ferrantini et al. 2009
  • "Dermacentroxenus" Wolbach 1919
  • "Candidatus Gigarickettsia" Vannini et al. 2014 [1] * "Candidatus Hemipteriphilus" Bing et al. 2013
  • "Candidatus Megaira" Schrallhammer et al. 2013
  • Occidentia Mediannikov et al. 2017
  • Orientia Tamura et al. 1995
  • "Candidatus Phycorickettsia" Yurchenko et al. 2018
  • Rickettsia da Rocha-Lima 1916 (Approved Lists 1980)
  • "Candidatus Sarmatiella" Castelli et al. 2021
  • "Candidatus Spectririckettsia" Castelli et al. 2019
  • "Candidatus Trichorickettsia" Vannini et al. 2014 [1]
  • "Candidatus Xenohaliotis" Friedman et al. 2000

The Rickettsiaceae are a family of bacteria. The genus Rickettsia is the most prominent genus within the family. The bacteria that eventually formed the mitochondrion (an organelle in eukaryotic cells) is believed to have originated from this family. Most human pathogens in this family are in genus Rickettsia. They spend part of their lifecycle in the bodies of arthropods such as ticks or lice, and are then transmitted to humans or other mammals by the bite of the arthropod. It contains Gram-negative bacteria, very sensitive to environmental exposure, thus is adapted to obligate intracellular infection. Rickettsia rickettsii is considered the prototypical infectious organism in the group.

Genomics

Comparative genomic analysis has identified three proteins, RP030, RP187 and RP192, which are uniquely found in members of the family Rickettsiaceae and serve as molecular markers for this family. [2] In addition, conserved signature indels in a number of proteins including a four-amino-acid insert in transcription repair coupling factor Mfd, a 10-amino-acid insert in ribosomal protein L19, one-amino-acid inserts each in the FtsZ protein and the major sigma factor 70, and a one-amino-acid deletion in exonuclease VII protein that are specific for the Rickettsiaceae species have been identified. [3]

Schematic ribosomal RNA phylogeny of Alphaproteobacteria
   Magnetococcidae   

  Magnetococcus marinus

   Caulobacteridae   

  Rhodospirillales, Sphingomonadales,
  Rhodobacteraceae, Hyphomicrobiales, etc.

  Holosporales

   Rickettsidae   
   Pelagibacterales   
   Pelagibacteraceae   

  Pelagibacter

  Subgroups Ib, II, IIIa, IIIb, IV and V

   Rickettsiales   

  Proto-mitochondria

   Anaplasmataceae   

  Ehrlichia

  Anaplasma

  Wolbachia

  Neorickettsia

   Midichloriaceae   

  Midichloria

   Rickettsiaceae   

  Rickettsia

  Orientia

The cladogram of Rickettsidae has been inferred by Ferla et al. [4] from the comparison of 16S + 23S ribosomal RNA sequences.

Related Research Articles

<span class="mw-page-title-main">Pseudomonadota</span> Phylum of Gram-negative bacteria

Pseudomonadota is a major phylum of Gram-negative bacteria. The renaming of several prokaryote phyla in 2021, including Pseudomonadota, remains controversial among microbiologists, many of whom continue to use the earlier name Proteobacteria, of long standing in the literature. The phylum Proteobacteria includes a wide variety of pathogenic genera, such as Escherichia, Salmonella, Vibrio, Yersinia, Legionella, and many others. Others are free-living (non-parasitic) and include many of the bacteria responsible for nitrogen fixation.

<i>Rickettsia</i> Genus of bacteria

Rickettsia is a genus of nonmotile, gram-negative, nonspore-forming, highly pleomorphic bacteria that may occur in the forms of cocci, bacilli, or threads. The term "rickettsia" has nothing to do with rickets ; the bacterial genus Rickettsia instead was named after Howard Taylor Ricketts, in honor of his pioneering work on tick-borne spotted fever.

The Aquificota phylum is a diverse collection of bacteria that live in harsh environmental settings. The name Aquificota was given to this phylum based on an early genus identified within this group, Aquifex, which is able to produce water by oxidizing hydrogen. They have been found in springs, pools, and oceans. They are autotrophs, and are the primary carbon fixers in their environments. These bacteria are Gram-negative, non-spore-forming rods. They are true bacteria as opposed to the other inhabitants of extreme environments, the Archaea.

The Chloroflexia are a class of bacteria in the phylum Chloroflexota. Chloroflexia are typically filamentous, and can move about through bacterial gliding. It is named after the order Chloroflexales.

<span class="mw-page-title-main">Chlamydiota</span> Phylum of bacteria

The Chlamydiota are a bacterial phylum and class whose members are remarkably diverse, including pathogens of humans and animals, symbionts of ubiquitous protozoa, and marine sediment forms not yet well understood. All of the Chlamydiota that humans have known about for many decades are obligate intracellular bacteria; in 2020 many additional Chlamydiota were discovered in ocean-floor environments, and it is not yet known whether they all have hosts. Historically it was believed that all Chlamydiota had a peptidoglycan-free cell wall, but studies in the 2010s demonstrated a detectable presence of peptidoglycan, as well as other important proteins.

<span class="mw-page-title-main">Rickettsiales</span> Order of bacteria

The Rickettsiales, informally called rickettsias, are an order of small Alphaproteobacteria. They are obligate intracellular parasites, and some are notable pathogens, including Rickettsia, which causes a variety of diseases in humans, and Ehrlichia, which causes diseases in livestock. Another genus of well-known Rickettsiales is the Wolbachia, which infect about two-thirds of all arthropods and nearly all filarial nematodes. Genetic studies support the endosymbiotic theory according to which mitochondria and related organelles developed from members of this group.

<i>Coxiella burnetii</i> Species of bacterium

Coxiella burnetii is an obligate intracellular bacterial pathogen, and is the causative agent of Q fever. The genus Coxiella is morphologically similar to Rickettsia, but with a variety of genetic and physiological differences. C. burnetii is a small Gram-negative, coccobacillary bacterium that is highly resistant to environmental stresses such as high temperature, osmotic pressure, and ultraviolet light. These characteristics are attributed to a small cell variant form of the organism that is part of a biphasic developmental cycle, including a more metabolically and replicatively active large cell variant form. It can survive standard disinfectants, and is resistant to many other environmental changes like those presented in the phagolysosome.

The Thermotogota are a phylum of the domain Bacteria. The phylum Thermotogota is composed of Gram-negative staining, anaerobic, and mostly thermophilic and hyperthermophilic bacteria.

<span class="mw-page-title-main">Bifidobacteriaceae</span> Family of bacteria

The Bifidobacteriaceae are the only family of bacteria in the order Bifidobacteriales. According to the 16S rRNA-based LTP release 106 published by 'The All-Species Living Tree' Project, the order Bifidobacteriales is a clade nested within the suborder Micrococcineae, also the genus Bifidobacterium is paraphyletic to the other genera within the family, i.e. the other genera are nested within Bifidobacterium.

Fibrobacterota is a small bacterial phylum which includes many of the major rumen bacteria, allowing for the degradation of plant-based cellulose in ruminant animals. Members of this phylum were categorized in other phyla. The genus Fibrobacter was removed from the genus Bacteroides in 1988.

<span class="mw-page-title-main">Pax genes</span> Family of transcription factors

In evolutionary developmental biology, Paired box (Pax) genes are a family of genes coding for tissue specific transcription factors containing an N-terminal paired domain and usually a partial, or in the case of four family members, a complete homeodomain to the C-terminus. An octapeptide as well as a Pro-Ser-Thr-rich C terminus may also be present. Pax proteins are important in early animal development for the specification of specific tissues, as well as during epimorphic limb regeneration in animals capable of such.

<span class="mw-page-title-main">Betaproteobacteria</span> Class of bacteria

Betaproteobacteria are a class of Gram-negative bacteria, and one of the eight classes of the phylum Pseudomonadota.

<span class="mw-page-title-main">Alphaproteobacteria</span> Class of bacteria

Alphaproteobacteria is a class of bacteria in the phylum Pseudomonadota. The Magnetococcales and Mariprofundales are considered basal or sister to the Alphaproteobacteria. The Alphaproteobacteria are highly diverse and possess few commonalities, but nevertheless share a common ancestor. Like all Proteobacteria, its members are gram-negative and some of its intracellular parasitic members lack peptidoglycan and are consequently gram variable.

<i>Orientia tsutsugamushi</i> Species of bacterium

Orientia tsutsugamushi is a mite-borne bacterium belonging to the family Rickettsiaceae and is responsible for a disease called scrub typhus in humans. It is a natural and an obligate intracellular parasite of mites belonging to the family Trombiculidae. With a genome of only 2.0–2.7 Mb, it has the most repeated DNA sequences among bacterial genomes sequenced so far. The disease, scrub typhus, occurs when infected mite larvae accidentally bite humans. Primarily indicated by undifferentiated febrile illnesses, the infection can be complicated and often fatal.

Fibrobacter succinogenes is a cellulolytic bacterium species in the genus Fibrobacter. It is present in the rumen of cattle. F. succinogenes is a gram negative, rod-shaped, obligate anaerobe that is a major contributor to cellulose digestion. Since its discovery in the 1950s, it has been studied for its role in herbivore digestion and cellulose fermentation, which can be utilized in biofuel production.

Rickettsia australis is a bacterium that causes a medical condition called Queensland tick typhus. The probable vectors are the tick species, Ixodes holocyclus and Ixodes tasmani. Small marsupials are suspected reservoirs of this bacterium.

<span class="mw-page-title-main">Pelagibacterales</span> Order of bacteria

The Pelagibacterales are an order in the Alphaproteobacteria composed of free-living marine bacteria that make up roughly one in three cells at the ocean's surface. Overall, members of the Pelagibacterales are estimated to make up between a quarter and a half of all prokaryotic cells in the ocean.

Conserved signature inserts and deletions (CSIs) in protein sequences provide an important category of molecular markers for understanding phylogenetic relationships. CSIs, brought about by rare genetic changes, provide useful phylogenetic markers that are generally of defined size and they are flanked on both sides by conserved regions to ensure their reliability. While indels can be arbitrary inserts or deletions, CSIs are defined as only those protein indels that are present within conserved regions of the protein.

Lysine Exporters are a superfamily of transmembrane proteins which export amino acids, lipids and heavy metal ions. They provide ionic homeostasis, play a role in cell envelope assembly, and protect from excessive concentrations of heavy metals in cytoplasm. The superfamily was named based on the early discovery of the LysE carrier protein of Corynebacterium glutamicum.

<span class="mw-page-title-main">Peptidoglycan recognition protein 3</span>

Peptidoglycan recognition protein 3 is an antibacterial and anti-inflammatory innate immunity protein that in humans is encoded by the PGLYRP3 gene.

References

  1. 1 2 Vannini C, Boscaro V, Ferrantini F, Benken KA, Mironov TI, Schweikert M, Görtz HD, Fokin SI, Sabaneyeva EV, Petroni G (2014). "Flagellar Movement in Two Bacteria of the Family Rickettsiaceae: A Re-Evaluation of Motility in an Evolutionary Perspective". PLOS ONE. 9 (2): e87718. Bibcode:2014PLoSO...987718V. doi: 10.1371/journal.pone.0087718 . PMC   3914857 . PMID   24505307.
  2. Gupta, R. S. and Mok, A. (2007). Phylogenomics and signature proteins for the alpha Proteobacteria and its main groups. BMC Microbiology. 7:106. doi : 10.1186/1471-2180-7-106.
  3. Gupta, R. S. (2005). Protein signatures distinctive of alpha proteobacteria and its subgroups and a model for alpha proteobacterial evolution. Critical Reviews in Microbiology. 3:101-135. doi : 10.1080/10408410590922393.
  4. Ferla MP, Thrash JC, Giovannoni SJ, Patrick WM (2013). "New rRNA gene-based phylogenies of the Alphaproteobacteria provide perspective on major groups, mitochondrial ancestry and phylogenetic instability". PLOS ONE. 8 (12): e83383. Bibcode:2013PLoSO...883383F. doi: 10.1371/journal.pone.0083383 . PMC   3859672 . PMID   24349502.