Holosporales | |
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Scientific classification | |
Domain: | Bacteria |
Phylum: | Pseudomonadota |
Class: | Alphaproteobacteria |
Subclass: | Caulobacteridae |
Order: | Holosporales Szokoli et al. 2020 [1] |
Families [2] | |
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Enterobacteriaceae is a large family of Gram-negative bacteria. It includes over 30 genera and more than 100 species. Its classification above the level of family is still a subject of debate, but one classification places it in the order Enterobacterales of the class Gammaproteobacteria in the phylum Pseudomonadota. In 2016, the description and members of this family were emended based on comparative genomic analyses by Adeolu et al.
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.
"Candidatus Pelagibacter", with the single species "Ca. P. communis", was isolated in 2002 and given a specific name, although it has not yet been described as required by the bacteriological code. It is an abundant member of the SAR11 clade in the phylum Alphaproteobacteria. SAR11 members are highly dominant organisms found in both salt and fresh water worldwide and were originally known only from their rRNA genes, first identified in the Sargasso Sea in 1990 by Stephen Giovannoni's laboratory at Oregon State University and later found in oceans worldwide. "Ca. P. communis" and its relatives may be the most abundant organisms in the ocean, and quite possibly the most abundant bacteria in the entire world. It can make up about 25% of all microbial plankton cells, and in the summer they may account for approximately half the cells present in temperate ocean surface water. The total abundance of "Ca. P. communis" and relatives is estimated to be about 2 × 1028 microbes.
Enterobacterales is an order of Gram-negative, non-spore forming, facultatively anaerobic, rod-shaped bacteria with the class Gammaproteobacteria. The type genus of this order is Enterobacter.
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.
Caulobacterales is an order of gram-negative pseudomonadota within the alpha subgroup.
In prokaryote nomenclature, Candidatus is used to name prokaryotic phyla that are well characterized but yet-uncultured. Contemporary sequencing approaches, such as 16S ribosomal RNA sequencing or metagenomics, provide much information about the analyzed organisms and thus allow to identify and characterize individual species. However, the majority of prokaryotic species remain uncultivable and hence inaccessible for further characterization in in vitro study. The recent discoveries of a multitude of candidate taxa has led to candidate phyla radiation expanding the tree of life through the new insights in bacterial diversity.
Candidatus Rhabdochlamydia is a genus of intracellular bacteria and the sole genus in the family Candidatus Rhabdochlamydiaceae. As a Candidatus taxon, no-one has yet managed to culture them in vitro for deposition in a culture collection.
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.
"Candidatus Midichloria" is a candidatus genus of Gram-negative, non-endospore-forming bacteria, with a bacillus shape around 0.45 µm in diameter and 1.2 µm in length. First described in 2004 with the temporary name IricES1, "Candidatus Midichloria" species are symbionts of several species of hard ticks. They live in the cells of the ovary of the females of this tick species. These bacteria have been observed in the mitochondria of the host cells, a trait that has never been described in any other symbiont of animals.
Archaea is a domain of single-celled organisms. These microorganisms lack cell nuclei and are therefore prokaryotes. Archaea were initially classified as bacteria, receiving the name archaebacteria, but this term has fallen out of use.
The Chloroflexota are a phylum of bacteria containing isolates with a diversity of phenotypes, including members that are aerobic thermophiles, which use oxygen and grow well in high temperatures; anoxygenic phototrophs, which use light for photosynthesis ; and anaerobic halorespirers, which uses halogenated organics as electron acceptors.
The Nitrososphaerota are a phylum of the Archaea proposed in 2008 after the genome of Cenarchaeum symbiosum was sequenced and found to differ significantly from other members of the hyperthermophilic phylum Thermoproteota. Three described species in addition to C. symbiosum are Nitrosopumilus maritimus, Nitrososphaera viennensis, and Nitrososphaera gargensis. The phylum was proposed in 2008 based on phylogenetic data, such as the sequences of these organisms' ribosomal RNA genes, and the presence of a form of type I topoisomerase that was previously thought to be unique to the eukaryotes. This assignment was confirmed by further analysis published in 2010 that examined the genomes of the ammonia-oxidizing archaea Nitrosopumilus maritimus and Nitrososphaera gargensis, concluding that these species form a distinct lineage that includes Cenarchaeum symbiosum. The lipid crenarchaeol has been found only in Nitrososphaerota, making it a potential biomarker for the phylum. Most organisms of this lineage thus far identified are chemolithoautotrophic ammonia-oxidizers and may play important roles in biogeochemical cycles, such as the nitrogen cycle and the carbon cycle. Metagenomic sequencing indicates that they constitute ~1% of the sea surface metagenome across many sites.
Nitrospirota is a phylum of bacteria. It includes multiple genera, such as Nitrospira, the largest. The first member of this phylum, Nitrospira marina, was discovered in 1985. The second member, Nitrospira moscoviensis, was discovered in 1995.
Liberibacter is a genus of Gram-negative bacteria in the Rhizobiaceae family. Detection of the liberibacteria is based on PCR amplification of their 16S rRNA gene with specific primers. Members of the genus are plant pathogens mostly transmitted by psyllids. The genus was originally spelled Liberobacter.
Chloroflexales is an order of bacteria in the class Chloroflexia. The clade is also known as filamentous anoxygenic phototrophic bacteria (FAP), as the order contains phototrophs that do not produce oxygen. These bacteria are facultative aerobic. They generally use chemotrophy when oxygen is present and switch to light-derived energy when otherwise. Most species are heterotrophs, but a few are capable of photoautotrophy.
"Procabacteriaceae" is a Candidatus family of uncultivated Gram-negative Betaproteobacteria. The sole genus, "Procabacter", was identified as an obligate endosymbiont of Acanthamoeba.
The Acidimicrobiia are a class of Actinomycetota, in which three families, eight genera, and nine species have been described, Acidimicrobium ferrooxidans is the type species of the order.
Caballeronia is a genus of bacteria from the family of Burkholderiaceae which has been reported to perform biological nitrogen fixation and promote plant growth