関: myxobacteria、Sorangium cellulosum

WordNet

bacteria that form colonies in self-produced slime; inhabit moist soils or decaying plant matter or animal waste (同)myxobacterium, myxobacter, gliding_bacteria, slime bacteria

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/08/03 17:57:49」(JST)

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The myxobacteria ("slime bacteria") are a group of bacteria that predominantly live in the soil and feed on insoluble organic substances. The myxobacteria have very large genomes, relative to other bacteria, e.g. 9–10 million nucleotides. Sorangium cellulosum has the largest (as of 2008) bacterial genome, at 13.0 million nucleotides.^[1] Myxobacteria are included among the delta group of proteobacteria, a large taxon of Gram-negative forms.

Myxobacteria can move actively by gliding. They typically travel in swarms (also known as wolf packs), containing many cells kept together by intercellular molecular signals. Individuals benefit from aggregation as it allows accumulation of extracellular enzymes which are used to digest food, this in turn increases feeding efficiency. Myxobacteria produce a number of biomedically and industrially useful chemicals, such as antibiotics, and export those chemicals outside of the cell.^[2]

Life cycle

When nutrients are scarce, myxobacterial cells aggregate into fruiting bodies (not to be confused with those in fungi), a process long-thought to be mediated by chemotaxis but now considered to be a function of a form of contact-mediated signaling.^[3]^[4] These fruiting bodies can take different shapes and colors, depending on the species. Within the fruiting bodies, cells begin as rod-shaped vegetative cells, and develop into rounded myxospores with thick cell walls. These myxospores, analogous to spores in other organisms, are more likely to survive until nutrients are more plentiful. The fruiting process is thought to benefit myxobacteria by ensuring that cell growth is resumed with a group (swarm) of myxobacteria, rather than as isolated cells. Similar life cycles have developed among certain amoebae, called cellular slime molds.

At a molecular level, initiation of fruiting body development is regulated by Pxr sRNA.^[5]^[6]

Myxobacteria such as Myxococcus xanthus and Stigmatella aurantiaca are used as model organisms for the study of development.

Clinical use

Metabolites secreted by Sorangium cellulosum known as epothilones have been noted to have antineoplastic activity. This has led to the development of analogs which mimic its activity. One such analog, known as Ixabepilone is a U.S. Food and Drug Administration approved chemotherapy agent for the treatment of metastatic breast cancer.^[7]

Various myxobacterial species as sketched by Roland Thaxter in 1892: Chondromyces crocatus (figs. 1–11), Stigmatella aurantiaca (figs. 12–19 and 25-28), Melittangium lichenicola (figs. 20–23), Archangium gephyra (fig. 24), Myxococcus coralloides (figs. 29-33), Polyangium vitellinum (figs. 34-36), and Myxococcus fulvus (figs. 37-41). Thaxter was the first taxonomist to recognize the bacterial nature of the myxobacteria. Previously, they had been misclassified as members of the fungi imperfecti.

References

^ Schneiker S et al. (2007). "Complete genome sequence of the myxobacterium Sorangium cellulosum". Nature Biotechnology 25 (11): 1281–1289. doi:10.1038/nbt1354. PMID 17965706.
^ Reichenbach H (2001). "Myxobacteria, producers of novel bioactive substances". J Ind Microbiol Biotechnol 27 (3): 149–56. doi:10.1038/sj.jim.7000025. PMID 11780785.
^ Kiskowski MA, Jiang Y, Alber MS (2004). "Role of streams in myxobacteria aggregate formation". Phys Biol 1 (3–4): 173–83. doi:10.1088/1478-3967/1/3/005. PMID 16204837.
^ Sozinova O, Jiang Y, Kaiser D, Alber M (2005). "A three-dimensional model of myxobacterial aggregation by contact-mediated interactions". Proc Natl Acad Sci USA 102 (32): 11308–12. doi:10.1073/pnas.0504259102. PMC 1183571. PMID 16061806.
^ Yu YT, Yuan X, Velicer GJ (May 2010). "Adaptive evolution of an sRNA that controls Myxococcus development". Science 328 (5981): 993. doi:10.1126/science.1187200. PMC 3027070. PMID 20489016. Retrieved 2010-07-22.
^ Fiegna F, Yu YT, Kadam SV, Velicer GJ (May 2006). "Evolution of an obligate social cheater to a superior cooperator". Nature 441 (7091): 310–4. doi:10.1038/nature04677. PMID 16710413.
^ "FDA Approval for Ixabepilone".

External links

The Myxobacteria Web Page
Video: Schwarmentwicklung und Morphogenese bei Myxobakterien
Video: Myxobacteria form Fruiting Bodies
Video: Myxococcus xanthus preying on an E. coli colony

English Journal

Enhanced production of undecylprodigiosin in Streptomyces coelicolor by co-cultivation with the corallopyronin A-producing myxobacterium, Corallococcus coralloides.

Schäberle TF, Orland A, König GM.SourceInstitute for Pharmaceutical Biology, University of Bonn, Nussallee 6, 53115, Bonn, Germany, till.schaeberle@uni-bonn.de.
Biotechnology letters.Biotechnol Lett.2013 Nov 19. [Epub ahead of print]
Prolific producers of natural products like streptomycetes and myxobacteria live in complex natural frameworks consisting of many microorganisms. Presumably intricate physiological and metabolic regulatory networks have evolved to enable the organisms to respond to intra- and interspecies interactio
PMID 24249103

Jahnellamides, α-Keto-β-Methionine-Containing Peptides from the Terrestrial Myxobacterium Jahnella sp.: Structure and Biosynthesis.

Plaza A, Viehrig K, Garcia R, Müller R.SourceDepartment of Microbial Natural Products, Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI) and Pharmaceutical Biotechnology, Saarland University , Campus C2 3, 66123 Saarbrücken, Germany.
Organic letters.Org Lett.2013 Nov 15;15(22):5882-5. doi: 10.1021/ol402967y. Epub 2013 Nov 7.
Two new cyclic peptides, termed jahnellamides A and B, were isolated from the myxobacterium Jahnella sp. Their structures were solved by NMR, ESIMS, and chemical derivatizations. Jahnellamides are a new class of α-ketoamide-containing peptides comprised of nonproteinogenic amino acids, including α
PMID 24199909

Concerted Action of P450 Plus Helper Protein To Form the Amino-hydroxy-piperidone Moiety of the Potent Protease Inhibitor Crocapeptin.

Viehrig K, Surup F, Harmrolfs K, Jansen R, Kunze B, Müller R.SourceHelmholtz Institute for Pharmaceutical Research Saarland, Helmholtz Centre for Infection Research, and Department of Pharmaceutical Biotechnology, Saarland University , Building C 2.3, D-66123, Saarbrücken, Germany.
Journal of the American Chemical Society.J Am Chem Soc.2013 Nov 13;135(45):16885-94. doi: 10.1021/ja4047153. Epub 2013 Oct 30.
The crocapeptins are described here as cyclic depsipeptides, isolated from cultures of the myxobacterium Chondromyces crocatus . Structure elucidation of the compounds revealed a cyanopeptolin-like skeleton, containing the characteristic amino-hydroxy-piperidone (Ahp)-heterocycle. Like the cyanopept
PMID 24171398

Japanese Journal

The Pathway of Leucine to Mevalonate in Halophilic Archaea : Efficient Incorporation of Leucine into Isoprenoidal Lipid with the Involvement of Isovaleryl-CoA Dehydrogenase in Halobacterium salinarum

Yamauchi Noriaki
Bioscience, biotechnology, and biochemistry 74(2), 443-446, 2010-02-23
… The pathway of leucine to mevalonate, which has attracted attention in the study of the biosynthesis of isoprenoid in parasitic protozoa and myxobacterium, was observed in the biosynthesis of the lipid core in halophilic archaea. …
NAID 10027552008

P-60 簡便なCystothiazole A,C,D及びMelithiazol Bの全合成(ポスター発表の部)

岩城雪,秋田弘幸
天然有機化合物討論会講演要旨集 (49), 655-660, 2007-08-24
… They were isolated from different strains of myxobacterium (Cystothiazoles A, C and D; …
NAID 110006682841

The First Hydroxylated Archazolid from the Myxobacterium Cystobacter violaceus : Isolation, Structural Elucidation and V-ATPase Inhibition

MENCHE Dirk,HASSFELD Jorma,STEINMETZ Heinrich,HUSS Markus,WIECZOREK Helmut,SASSE Florenz
Journal of antibiotics = An International Journal Devoted to Research on Bioactive Microbial Products 60(5), 328-331, 2007-05-25
NAID 10019495971