Modulibacteria is a
bacterial phylum formerly known as KS3B3 or GN06. It is a
candidate
A candidate, or nominee, is the prospective recipient of an award or honor, or a person seeking or being considered for some kind of position; for example:
* to be elected to an office — in this case a candidate selection procedure occurs.
* t ...
phylum, meaning there are no cultured representatives of this group. Members of the Modulibacteria phylum are known to cause fatal filament overgrowth (bulking) in high-rate industrial
anaerobic wastewater treatment
bioreactor
A bioreactor refers to any manufactured device or system that supports a biologically active environment. In one case, a bioreactor is a vessel in which a chemical reaction, chemical process is carried out which involves organisms or biochemistry, ...
s.
The Modulibacteria phylum was first proposed in 2006 by two independent research groups based on analyses of
16S rRNA 16S rRNA may refer to:
* 16S ribosomal RNA
16 S ribosomal RNA (or 16 S rRNA) is the RNA component of the 30S subunit of a prokaryotic ribosome ( SSU rRNA). It binds to the Shine-Dalgarno sequence and provides most of the SSU structure.
The g ...
gene sequences. One group recovered Modulibacteria sequences from the a
hypersaline microbial mat from
Guerrero Negro
Guerrero Negro is the largest town located in the municipality of Mulegé in the Mexican state of Baja California Sur (BCS). It had a population of 14,316 in the 2015 census. The town is served by Guerrero Negro Airport.
Whale Festival
The ...
(Baja California Sur, Mexico) and used the provisional name GN06 for the novel
phylum
In biology, a phylum (; plural: phyla) is a level of classification or taxonomic rank below kingdom and above class. Traditionally, in botany the term division has been used instead of phylum, although the International Code of Nomenclature f ...
, while the other recovered sequences from sulfur-rich black mud
marine sediments
Marine sediment, or ocean sediment, or seafloor sediment, are deposits of insoluble particles that have accumulated on the seafloor. These particles have their origins in soil and rocks and have been transported from the land to the sea, mainly ...
(CA, USA) and used the provisional name KSB3.
The first
genomic
Genomics is an interdisciplinary field of biology focusing on the structure, function, evolution, mapping, and editing of genomes. A genome is an organism's complete set of DNA, including all of its genes as well as its hierarchical, three-dim ...
insights into the phylum were achieved in 2015, at which time the name "Modulibacteria" was proposed.
Two genomes were recovered from
methanogenic
Methanogenesis or biomethanation is the formation of methane coupled to energy conservation by microbes known as methanogens. Organisms capable of producing methane for energy conservation have been identified only from the Domain (biology), domai ...
sludge samples of a full-scale
upflow anaerobic sludge blanket
Upflow anaerobic sludge blanket (UASB) technology, normally referred to as UASB reactor, is a form of anaerobic digester that is used for wastewater treatment.
The UASB reactor is a methanogenic (methane-producing) digester that evolved from the ...
(UASB) reactor treating a high-strength organic
wastewater discharged from a food-processing factory.
Through a combination of genome-based
metabolic
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
reconstruction and microscopic observation, it was determined that the two studied Modulibacteria species (''Moduliflexus flocculans'' and ''Vecturithrix granuli'') produce filamentous structures and are
Gram-negative
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall ...
, strictly anaerobic
fermenters capable of non-
flagellar
A flagellum (; ) is a hairlike appendage that protrudes from certain plant and animal sperm cells, and from a wide range of microorganisms to provide motility. Many protists with flagella are termed as flagellates.
A microorganism may have fro ...
based gliding motility. Both have an unusually large number of sensory and response
regulator genes compared to other bacteria.
Members of the Modulibacteria phylum have been detected in a variety of environments in addition to bioreactors and hypersaline mats, such as wetland sediments
FJ516883.1, the
dolphin
A dolphin is an aquatic mammal within the infraorder Cetacea. Dolphin species belong to the families Delphinidae (the oceanic dolphins), Platanistidae (the Indian river dolphins), Iniidae (the New World river dolphins), Pontoporiidae (the ...
mouth, and a
tubeworm
A tubeworm is any worm-like sessile invertebrate that anchors its tail to an underwater surface and secretes around its body a mineral tube, into which it can withdraw its entire body.
Tubeworms are found among the following taxa:
* Annelida, the ...
from a
coldseepFM165273.
Taxonomy
The following taxonomy was proposed by Sekiguchi et al. 2015.
Phylogeny by Annotree v1.2.0 which uses the GTDB 05-RS95 (
Genome Taxonomy Database)
* Class "Moduliflexia"
Sekiguchi et al. 2015 Sekiguchi et al. 2015">Vecturitrichia" Sekiguchi et al. 2015** Order "Moduliflexales"
Sekiguchi et al. 2015 Sekiguchi et al. 2015">Vecturatrichales" Sekiguchi et al. 2015*** Family "Moduliflexaceae"
Sekiguchi et al. 2015 Sekiguchi et al. 2015">Vecturatrichaceae" Sekiguchi et al. 2015**** Genus "''Candidatus''
Moduliflexus"
Sekiguchi et al. 2015
***** Species "''Ca.'' M. flocculans"
Sekiguchi et al. 2015
**** Genus "''Candidatus''
Vecturithrix"
Sekiguchi et al. 2015
***** Species "''Ca.'' V. granuli"
Sekiguchi et al. 2015
References
{{Bacteria classification, state=expanded
Bacteria phyla
Candidatus taxa