Sorangium cellulosum strain

After the identification of the paclitaxel mechanism of action, several additional microtubule stabilizing agents were discovered from natural sources (Chart 9). Among them, epothilones (12-15) are the most studied and characterized. Epothilones A and B (12,13) were first isolated by Hofle and coworkers [54] from a myxobacterium (Sorangium cellulosum strain 90) in 1993, while their activity in stabilizing microtubule similarly to paclitaxel was reported for the first time by Bollag and co-workers in 1995 [55], Experiments with radio-labeled paclitaxel... 

In a screening of myxobacteria for antibacterial metabolites, the Sorangium cellulosum strain So ce678 was selected for its activity against Staphylococcus aureus [55]. The active compounds were produced as two rather lipophilic active compounds, i.e. tartrolons B (16) and C (17). Tartrolon B was identified as a boric acid ester of tartrolon A3, whereas tartrolon A1 and tartrolon A2 are stereoisomers of tartrolon A3. All components could be chemically converted into eaeh other. 

H., Wray, V. et al. (1994) Disorazoles, highly cytotoxic metabolites from the Sorangicin-producing bacterium Sorangium cellulosum, strain So cel2. 

The secondary metabolites tuscolid, tuscoron A, and tuscoron B were isolated in 2004 from the myxobacterium Sorangium cellulosum (strains So cel401 and So cel383) isolated from soil samples collected near Tucson (So cel401) and Snow Flake (So cel383), Arizona. Both strains were found to be relatively good producers of both... 

Ripostatins A and B were isolated by Reichenbach et al. [81] as active principle of the myxobacterium Sorangium cellulosum (strain So ce 377) from a soil sample collected from Kenya. Both the compounds exhibit activity across a narrow antibiotic spectrum [82] against some strains of Staphylococcus aureus with minimum inhibitory concentration (MIC) values of 1 gg ml". From a structural point of view, ripostatin B 85 (Scheme 6.16) is a polyunsaturated 14-membered macrolide having three chiral centers in its core skeleton. Christmann et al. [83] reported the synthesis of 85 by RCM of ester 83. 

Figure 7.5). Epothilone A was isolated from myxobacteria (Sorangium cellulosum strain 90) and has shown potent... 

Sorangium cellulosum is an ubiquitous soil bacterium that belongs to the order Myxococcales. It has the ability to glide over solid surfaces, to live in a biofilm and form fruiting bodies. Members of this taxon are a particularly rich source of metabolites with remarkable biological activities [177]. From one strain, another example of N-acyl-4-methoxy-3-pyrrolin-2-ones has been isolated. Eliamid (110) has been claimed to have cytostatic, nematocidal and fungicidal activities [178]. 

From strains of Sorangium cellulosum a chlorodivinylether, maracen (110), was isolated. It is active against Mycobacterium tuberculosis (IC99 < 12.5 pg/ml) and only slightly toxic against murine fibroblasts L929 (> 24 pg/ml) [89]. 

Figure 9 Type III PKS biosynthesis In myxobacteria. Biosynthesis of flaviolin (20) catalyzed by a type III PKS (CHS) from Sorangium cellulosum So ce56. The primary product released from the CHS, 1,3,6,8-tetrahydroxynaphthalene (26), Is spontaneously oxidized to form 20. Neither 26 nor 20 has been Identified In the myxobacterial strain. Indicating that the CHS-encodIng gene Is silent under the tested conditions. Activation of the type III PKS-encodIng gene by heterologous expression In Pseudomonas putida led to the formation of the red pigment 20 In the P. putida CHS strain (see picture).

Ripostatins A (73) and B are 14-membered ring macrolides produced by myx-obacterium Sorangium cellulosum [93]. They acted especially on Staphylococcus aureus and inhibited eubacterial RNA polymerase. Compound 73 exists as an equilibrium mixture of ketone form and hemiacetal form in methanol. An unpig-mented strain of Chromobacterium violaceum produces another 14-membered ring macrolide, aerocavin (74), which is active against gram-positive and gramnegative bacteria [94]. 

Perlova, O., Gerth, K., Hans, A., Kaiser, O. et al (2006) Identification and analysis of the chivosazol biosynthetic gene cluster from the myxobacterial model strain Sorangium cellulosum So ce56. /. Biotechnol, 121 (2), 174-191. 

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