Haloferax mediterranei

Haloferax mediterranei is a species of archaea in the family Haloferacaceae.[1]

Haloferax mediterranei
SEM image of Haloferax mediterranei.
Scientific classification Edit this classification
Domain: Archaea
Kingdom: Euryarchaeota
Class: Halobacteria
Order: Haloferacales
Family: Haloferacaceae
Genus: Haloferax
Species:
H. mediterranei
Binomial name
Haloferax mediterranei
(Rodriguez-Valera et al. 1983) Torreblanca et al. 1987[1]
Synonyms
  • Halobacterium mediterranei Rodriguez-Valera et al. 1983[1]

Discovery

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Haloferax mediterranei was discovered in 1983 in marine salterns in the village of Santa Pola, Spain.[2] The species was initially named Halobacterium mediterranei, then renamed Haloferax mediterranei in 1986.[3] Haloferax mediterranei is the fastest-growing known member of the Halobacteriales under optimal laboratory conditions, but it is relatively rare in the environment.[4] The full genome of H. mediterranei was sequenced in 2012.[5]

Metabolism and Growth Conditions

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Haloferax mediterranei is the fastest-growing archaeon in the Halobacteriales family,[4] with generation times as low as 1.2 hours reported under optimal laboratory growth conditions.[6] Haloferax mediterranei is able to use a variety of compounds as carbon and energy sources,[7] and can accumulate materials to serve as a source of carbon and energy, as well as use organic and inorganic nitrogen sources.[4] H. mediterranei is an extremely versatile microorganism that can anaerobically or aerobically, tolerate a wide range of salinities (between 10% and 32.5%), a wide range of pH values (between 5.75 and 8.75) and a wide range of temperatures (between 18 and 55oC).[7][6][4] It can also tolerate a variety of high metal concentrations, such as nickel, lithium, cobalt and arsenic, which are toxic to most organisms.[6]

Morphology and Cell Division

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Haloferax mediterranei is an extremely pleomorphic organism, cells are usually flat disks.[4] Like Haloferax volcanii, it performs cell division through the formation of an FtsZ ring.[8]

Biofilm and Exopolysaccharide formation

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Haloferax mediterranei produces a mucous exopolysaccharide matrix that accumulates as a top layer in liquid medium.[9] This is a widespread strategy in the microbial world that helps biofilms adhere to surfaces, as well as protects cells from pH and temperature variations and radiation.[10] These exopolysaccharides have been studied as potential emulsifiers for industry.[9] The unshaken biofilms of H. mediterranei in liquid cultures rapidly rearrange into a honeycomb formation pattern upon exposure to air, a phenomenon that has yet to be fully elucidated.[11]

PHA and PHB synthesis

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H. mediterranei, when grown under phosphate limitation,[12] produces polyhydroxyalkanoates, a type of biodegradable thermoplastic currently commercially produced using bacteria.[13] It has been suggested that H. mediterranei is a good candidate for industrial production of biodegradable thermoplastics due to its fast growth, low contamination rates and ease of lysis.[14] Deleting the genes responsible for exopolysaccharide synthesis results in a 20% increase in the amount of PHAs in the cell.[13] Increasing the salt concentration of the media also increased the concentration of PHAs produced.[15]

Gas Vesicles

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Like some other members of the Halobacteriales group, notably Halobacterium salinarum, Haloferax mediterranei produces gas vesicles, believed to act aiding buoyancy. The production of gas vesicles only occurs in high salt concentrations and once cells have reached stationary phase.[4] By transforming 14 genes from the vac cluster of H. mediterranei into a gas-vesicle deficient archaeon H. volcanii, researchers found that H. volcanii is able to produce functional gas vacuoles.[16][17]

References

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  1. ^ a b c Page Species: Haloferax mediterranei on "LPSN - List of Prokaryotic names with Standing in Nomenclature". Deutsche Sammlung von Mikroorganismen und Zellkulturen. Retrieved 2022-07-15.
  2. ^ Mojica, Francisco J. M.; Rodriguez-Valera, Francisco (2016-06-15). "The discovery of CRISPR in archaea and bacteria". The FEBS Journal. 283 (17). Wiley: 3162–3169. doi:10.1111/febs.13766. hdl:10045/57676. ISSN 1742-464X. PMID 27234458. S2CID 42827598.
  3. ^ Torreblanca, Marina; Rodriguez-Valera, F.; Juez, Guadalupe; Ventosa, Antonio; Kamekura, Masahiro; Kates, Morris (1986). "Classification of Non-alkaliphilic Halobacteria Based on Numerical Taxonomy and Polar Lipid Composition, and Description of Haloarcula gen. nov. and Haloferax gen. nov". Systematic and Applied Microbiology. 8 (1–2). Elsevier BV: 89–99. doi:10.1016/s0723-2020(86)80155-2. ISSN 0723-2020.
  4. ^ a b c d e f Oren, Aharon; Hallsworth, John E. (2014-08-28). "Microbial weeds in hypersaline habitats: the enigma of the weed-like Haloferax mediterranei". FEMS Microbiology Letters. 359 (2). Oxford University Press (OUP): 134–142. doi:10.1111/1574-6968.12571. ISSN 0378-1097. PMID 25132231. S2CID 5047263.
  5. ^ Han, Jing; Zhang, Fan; Hou, Jing; Liu, Xiaoqing; Li, Ming; Liu, Hailong; Cai, Lei; Zhang, Bing; Chen, Yaping; Zhou, Jian; Hu, Songnian; Xiang, Hua (2012-08-15). "Complete Genome Sequence of the Metabolically Versatile Halophilic Archaeon Haloferax mediterranei, a Poly(3-Hydroxybutyrate- co -3-Hydroxyvalerate) Producer". Journal of Bacteriology. 194 (16). American Society for Microbiology: 4463–4464. doi:10.1128/jb.00880-12. ISSN 0021-9193. PMC 3416209. PMID 22843593.
  6. ^ a b c Matarredona, Laura; Camacho, Mónica; Zafrilla, Basilio; Bravo-Barrales, Gloria; Esclapez, Julia; Bonete, María-José (2021-02-08). "The Survival of Haloferax mediterranei under Stressful Conditions". Microorganisms. 9 (2). MDPI AG: 336. doi:10.3390/microorganisms9020336. ISSN 2076-2607. PMC 7915512. PMID 33567751.
  7. ^ a b Trujillo, Martha E; Dedysh, Svetlana; Devos, Paul; Hedlund, Brian; Kämpfer, Peter; Rainey, Fred A; Whitman, William B, eds. (2015-04-17). Bergey's Manual of Systematics of Archaea and Bacteria. Wiley. doi:10.1002/9781118960608. ISBN 978-1-118-96060-8.
  8. ^ Poplawski, Andrzej; Gullbrand, Björn; Bernander, Rolf (2000). "The ftsZ gene of Haloferax mediterranei: sequence, conserved gene order, and visualization of the FtsZ ring". Gene. 242 (1–2). Elsevier BV: 357–367. doi:10.1016/s0378-1119(99)00517-x. ISSN 0378-1119. PMID 10721730.
  9. ^ a b Antón, Josefa; Meseguer, Inmaculada; Rodríguez-Valera, F. (1988). "Production of an Extracellular Polysaccharide by Haloferax mediterranei". Applied and Environmental Microbiology. 54 (10). American Society for Microbiology: 2381–2386. doi:10.1128/aem.54.10.2381-2386.1988. ISSN 0099-2240. PMC 204266. PMID 16347749.
  10. ^ Poli, Annarita; Di Donato, Paola; Abbamondi, Gennaro Roberto; Nicolaus, Barbara (2011). "Synthesis, Production, and Biotechnological Applications of Exopolysaccharides and Polyhydroxyalkanoates by Archaea". Archaea. 2011. Hindawi Limited: 1–13. doi:10.1155/2011/693253. ISSN 1472-3646. PMC 3191746. PMID 22007151.
  11. ^ Schiller, Heather; Schulze, Stefan; Mutan, Zuha; de Vaulx, Charlotte; Runcie, Catalina; Schwartz, Jessica; Rados, Theopi; Bisson Filho, Alexandre W.; Pohlschroder, Mechthild (2020-12-23). "Haloferax volcanii Immersed Liquid Biofilms Develop Independently of Known Biofilm Machineries and Exhibit Rapid Honeycomb Pattern Formation". mSphere. 5 (6). American Society for Microbiology. doi:10.1128/msphere.00976-20. ISSN 2379-5042. PMC 7771232. PMID 33328348.
  12. ^ Rodriguez-Valera, F.; Lillo, J. A. Garcia; Antón, Josefa; Meseguer, Inmaculada (1991). "Biopolymer Production by Haloferax Mediterranei". General and Applied Aspects of Halophilic Microorganisms. Boston, MA: Springer US. pp. 373–380. doi:10.1007/978-1-4615-3730-4_45. ISBN 978-1-4613-6660-7.
  13. ^ a b Zhao, Dahe; Cai, Lei; Wu, Jinhua; Li, Ming; Liu, Hailong; Han, Jing; Zhou, Jian; Xiang, Hua (2012-09-27). "Improving polyhydroxyalkanoate production by knocking out the genes involved in exopolysaccharide biosynthesis in Haloferax mediterranei". Applied Microbiology and Biotechnology. 97 (7). Springer Science and Business Media LLC: 3027–3036. doi:10.1007/s00253-012-4415-3. ISSN 0175-7598. PMID 23015099. S2CID 253771071.
  14. ^ Bhattacharyya, Anirban; Pramanik, Arnab; Maji, Sudipta Kumar; Haldar, Saubhik; Mukhopadhyay, Ujjal Kumar; Mukherjee, Joydeep (2012-07-09). "Utilization of vinasse for production of poly-3-(hydroxybutyrate-co-hydroxyvalerate) by Haloferax mediterranei". AMB Express. 2 (1). Springer Science and Business Media LLC: 34. doi:10.1186/2191-0855-2-34. ISSN 2191-0855. PMC 3507687. PMID 22776040.
  15. ^ Cui, You-Wei; Gong, Xiao-Yu; Shi, Yun-Peng; Wang, Zhiwu (Drew) (2017). "Salinity effect on production of PHA and EPS byHaloferax mediterranei". RSC Advances. 7 (84). Royal Society of Chemistry (RSC): 53587–53595. doi:10.1039/c7ra09652f. ISSN 2046-2069. S2CID 90828798.
  16. ^ Offner, Sonja; Ziese, Ulrike; Wanner, Gerhard; Typke, Dieter; Pfeifer, Felicitas (1998-05-01). "Structural characteristics of halobacterial gas vesicles". Microbiology. 144 (5). Microbiology Society: 1331–1342. doi:10.1099/00221287-144-5-1331. ISSN 1350-0872. PMID 9611808.
  17. ^ Beard, Steven J.; Hayes, Paul K.; Pfeifer, Felicitas; Walsby, Anthony E. (2002). "The sequence of the major gas vesicle protein, GvpA, influences the width and strength of halobacterial gas vesicles". FEMS Microbiology Letters. 213 (2). Oxford University Press (OUP): 149–157. doi:10.1111/j.1574-6968.2002.tb11299.x. ISSN 0378-1097. PMID 12167531. S2CID 19696507.


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