Amycolatopsis

Amycolatopsis is a genus of bacteria in the family of Pseudonocardiaceae in the order of Actinomycetales. All species of the genus are gram positive with a high GC content in bacterial DNA. Like other members of the Actinomycetales they form filamentous cell structures that resemble the hyphae of fungi. This meant that some species previously assigned to other genera such as Streptomyces or Nocardia, which are also counted among the Actinomycetales. How Streptomyces also form numerous types of Amycolatopsis antibiotics and are found in the soil.

• 2.1 Outer systematics
• 2.2 Internal systematics
• 2.3 Notes
• 2.4 Etymology

• 4.1 Literature
• 4.2 Notes and references

Features

Appearance

The cells of the species of Amycolatopsis are gram positive. The cells are the typical of many representatives of the Actinomycetales form as filaments. This similar to the hyphae of fungi seeing structures in diameter 0.5-2.0 microns wide and branched. Often, the hyphae disintegrate into individual cube-shaped cells. As for the mushrooms, one can distinguish between air and substrate mycelium. The substrate mycelium develops in the culture medium, while the aerial mycelium is formed from cells grown in the gas space above the culture medium. The substrate mycelium as well as the aerial mycelium can be colored pigments also continue to be released into the culture medium. However, do not develop all kinds an aerial mycelium. If available, can be observed also in these hyphae to fragment at the upper end. In this case, chains of spore -like, cube-shaped to ovoid cells are formed. The other genera of bacteria ( eg Bacillus or Sporosarcina ) typical endospores are not formed. The cells of Amycolatopsis are not capable of active motion. The bacterial cell wall is - unlike in the genera Nocardia and Mycobacterium - not acid-resistant.

Growth and metabolism

All kinds of Amycolatopsis are heterotrophic, they do not perform photosynthesis. Some species are strictly aerobic, that is dependent on oxygen. Others are facultative aerobic, they can live without oxygen. The catalase test is positive. Amycolatopsis species may use many organic compounds for their metabolism and break these various carbohydrates and sugar alcohols are utilized under acid formation. The temperatures for optimal growth are for most types of 20-30 ° C, they are mesophilic. The optimum pH of the nutrient medium is suitable for most types from 6.0 to 9.0.

Studies by Shu - Kun Tang et al 2010 led to an extended description of the species. The researchers found that even alkaliphilic species ( bacteria, which prefer higher pH values ​​for growth ) and halophilic species ( these require higher concentrations of sodium chloride for growth ) belong to the genus. In addition to the mesophilic include thermophilic species to species, so bacteria prefer higher temperatures for growth. So, for example, grows optimally Amycolatopsis halophila, if the culture medium contains 5% NaCl, and tolerates a salt content of up to 15%. It grows optimally at 37 ° C, and can tolerate temperatures up to 45 ° C. Even more pronounced is the thermophilicity at A. eurytherma, A. and A. methanolica thermoflava that still grow well even at 50 ° C.

For cultivation of Amycolatopsis species to conventional nutrient media can be used, on the basis of peptone ( such as casein - soy peptone agar ) and yeast extract. Certain additives are often still used. Suitable additives mannitol or glycerol are ( glycerol), and soybean meal, starch and oat flour are used. More supplines ( growth-promoting substances) are asparagine and tyrosine. The culture media must be incubated for a longer period until colonies are visible, usual 14 days.

Chemotaxonomic features

The murein layer of the cell wall containing the amino acid meso -diaminopimelic acid as diagnostically important amino acid in the peptide bridge, and also glutamic acid or alanine. The peptidoglycan type is A1γ. Diagnostically important sugars are galactose and arabinose. The extended description of the genus by Shu- Kun Tang et al 2010, however, showed that arabinose is not always present or may occur only in traces. Mycolic acids are not formed. The main menaquinone is MK -9 ( H2) or MK -9 ( H4). After Tang mainly occur MK -9 ( H4 ) and MK -8 ( H4). The phospholipids in the cell membrane to the Type II Phospholipidmuster, it is either phosphatidylethanolamine or Phosphatidylmethylethanolamin available or both compounds occur. In addition, also other phosphoglycerides occur. A few typical fatty acids in the cell membrane can not be fixed. The fatty acid contains saturated fatty acids such as C16: 0 ( palmitic or hexadecanoic acid ) and C17: 0 ( heptadecanoic or margaric ), and branched chain fatty acids such as iso- C15: 0 (iso- pentadecanoic acid ) and iso- C16: 0 (iso - hexadecanoic acid ) occur. Are also 2-hydroxy- fatty acids (see α -hydroxycarboxylic acids ), such as iso - C15: 0 2 -OH to find.

The GC content in the bacterial DNA is 66 to 75 mole percent, which corresponds to the position in the Department of Actinobacteria. The genome of several species has also been completely sequenced. Similar to Streptomyces species, which also have a distinct secondary metabolism, the genome falls even with them on its size. In A. orientalis, the genome size of the bacterial chromosome is 8949 kilobase pairs (kb ), which is almost twice the size of the genome of Escherichia coli ( 4600 kb). Unlike Streptomyces species ( which have a linear chromosomes ), the bacterial chromosome of the studied so far Amycolatopsis species is present as a circular molecule. Plasmids were also found, for example in A. and A. orientalis benzoatilytica.

System

Outer systematics

The genus Amycolatopsis in the family of Pseudonocardiaceae will be provided to the subordination of Pseudonocardineae in the order of Actinomycetales. Since 2011 the family Pseudonocardiaceae contains (see Note 1 ) next Amycolatopsis and Prauserella further genera of Actinosynnemataceae family were formerly attributed to, for example the genus Saccharothrix.

Inside systematics

Amycolatopsis orientalis is the type species of the genus. From the genus Amycolatopsis are more than 60 species are known (as of 2014):

• Amycolatopsis alba Mertz & Yao 1993
• Amycolatopsis albidoflavus Lee & Hah 2001
• Amycolatopsis australiensis Tan et al. 2006
• Amycolatopsis azurea ( Omura et al., 1983) Henssen et al. 1987
• Amycolatopsis balhimycina Wink et al. 2003
• Amycolatopsis bartoniae Zucchi et al. 2012
• Amycolatopsis benzoatilytica Majumdar et al. 2006
• Amycolatopsis bullii Zucchi et al. 2012
• Amycolatopsis cihanbeyliensis Tatar et al. 2013
• Amycolatopsis circi Everest & Meyers 2012
• Amycolatopsis coloradensis Labeda 1995
• Amycolatopsis decaplanina Wink et al. 2004
• Amycolatopsis dongchuanensis Nie et al. 2012
• Amycolatopsis echigonensis Ding et al. 2007
• Amycolatopsis endophytica Miao et al. 2012
• Amycolatopsis equina Everest & Meyers 2012
• Amycolatopsis eurytherma Kim et al. 2002
• Amycolatopsis granulosa Zucchi et al. 2012
• Amycolatopsis halophila Tang et al. 2010
• Amycolatopsis halotolerans Lee 2006
• Amycolatopsis helveola Tamura et al. 2010
• Amycolatopsis hippodromi Everest & Meyers 2012
• Amycolatopsis japonica Corrig. Goodfellow et al. 1997
• Amycolatopsis jejuensis Lee 2006
• Amycolatopsis jiangsuensis Xing et al. 2014
• Amycolatopsis kentuckyensis Labeda et al. 2003
• Amycolatopsis keratiniphila Al- Musallam et al. 2003 Amycolatopsis keratiniphila subsp. keratiniphila (Al- Musallam et al. 2003) Wink et al. 2003
• Amycolatopsis keratiniphila subsp. nogabecina Wink et al. 2003

• Amycolatopsis orientalis subsp. orientalis ( Pittenger & Brigham 1956) Lechevalier et al. 1986 (see Note 2 )

Comments

In the genus exist currently (as of 2014) 61 described species. Amycolatopsis although in nature is common, only part of the types described so far. The genus is the subject of intensive research. Alone between 2004 and 2006 as 11 new species of the genus have been described, in the period from 2007 to February 2014 there were 29 new species. For many species there are synonyms, as they were previously assigned to other genera, especially the genera Nocardia and Streptomyces. These genera also belong to the order Actinomycetales and before the establishment of the genus Amycolatopsis 1986 species have been assigned to the genera known at that time. Thus, the type species Amycolatopsis orientalis in 1956 was designated in the description as Streptomyces orientalis, classified in 1970 as Nocardia orientalis and 1981 as Actinomyces orientalis again assigned to a different genus. Amycolatopsis lurida is also conducted under the synonym Nocardia lurida.

Etymology

The genus Amycolatopsis was first described in 1986 by Mary P. Lechevalier, simultaneously with the genus Amycolata. This genus was, however, disbanded in 1994 and attributed to the members of the genus Pseudonocardia. The genus name Amycolata is composed of the Greek prefix a ( negation, " not " ), the Greek word tomyces ( "mushroom" ) and the Latin suffix ata ( designation of origin of a relationship). In order to distinguish the newly discovered genus to the then known genera Mycobacterium, Nocardia, Rhodococcus and Corynebacterium is exposed ( in the order Actinomycetales ) because Amycolata not mycolic acids ( certain fatty acids ) has. The genus name Amycolatopsis again refers Amycolata, with the addition of the Greek word opsis ( " Appearance "), it is shown that Amycolatopsis has a similar appearance to Amycolata.

Occurrence and significance

The habitat of Amycolatopsis species is similar to the representatives of the genera Nocardia, Rhodococcus or Streptomyces, typically the bottom. For example, A. orientalis, A. lurida and A. mediterranei were isolated from the soil. Also A. keratiniphila comes from the soil and has been found in Kuwait, during the search in India led to the discovery of A. balhimycina, A. and A. tolypomycina vancoresmycina. A. ultiminotia was discovered in the rhizosphere. Even arid soils are the habitat of many species, such as in the Atacama desert. Also from vegetable waste, plant material, clinical samples, the wall of a hypogene cave, ocean sediment, and the sediment of a salt lake Amycolatopsis species were isolated. A veterinary medi hiss importance (eg BA kentuckyensis ) for some species, as they can cause placentitis (infection of the uterus) in horses.

Many species of the genus play an important ecological role in material degradation, as they can break down difficult -to-decompose organic compounds such as methanol (A. methanolica ) and keratin (A. keratiniphila ). And aromatic hydrocarbons can be decomposed, such as meta- hydroxy benzoic acid by A. benzoatilytica. Some species are extremely heavy-metal- tolerant and tolerate high concentrations of nickel or copper. A. tucumanensis is even able to take copper from contaminated soil and therefore is eligible for microbiological remediation into consideration. Some strains can produce vanillin from ferulic acid.

From numerous species of the genus antibiotics are produced, such as ristocetin by A. lurida. With the intention to find the study of soil samples in India bacterial strains that produce antibiotics that are effective against MRSA (methicillin-resistant Staphylococcus aureus ), 2003 was successful: So the glycopeptide antibiotic vancomycin is synthesized by A. vancoresmycina. Further, effective against MRSA antibiotics are Tolypomycin and Nogabecin subsp by A. tolypomycina or A. keratiniphila. nogabecina are produced. The rifamycins, a separate group of antibiotics are synthesized by Amycolatopsis species, initially this was mediterranei observed in a bacterial strain of A., which was established in 2004 as a separate species A. rifamycinica.

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