Ornithine lipids (OLs) are phosphorus-free lipids found in many bacteria grown under phosphate deprivation, a condition that activates the PhoBR system and leads to phosphate uptake and metabolism. Two OL synthesis pathways have already been described. One depends on OlsB and OlsA acyltransferases to add, respectively, the first and second acyl chains to an ornithine molecule. The other pathway is carried out by OlsF, a bifunctional enzyme responsible for both acylation steps. Although Vibrio cholerae lacks olsBA genes, an olsF homologue (vc0489) was identified in its genome. In this work we demonstrated that V. cholerae produces OLs and expresses vc0489 in response to phosphate depletion, in a PhoBR-dependent manner. In Escherichia coli, under similar condition, vc0489 expression leads to OL accumulation. These results indicate a strong connection between OL synthesis and VC0489 from V. cholerae and, for the first time, a direct regulation of an olsF homologue by the PhoBR system.

We report a simple, fast, and eco-friendly solvent-free protocol for the synthesis of 2-aminothiazoles and 2-amino-1,3-selenazoles (16 examples) through Hantzsch condensation without the use of a catalyst. It is noteworthy that this type of procedure is unprecedented for the synthesis of 1,3-selenazoles. Reactions proceed to completion in a few seconds and products are obtained in moderate to excellent yields after easy workup. Moreover, the synthesis of 4-(2-amino-1,3selenazol-4-yl)benzonitrile hydrobromide is reported for the first time.

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A very fast method for the synthesis of the title thiazoles and selenazoles through Hantzsch cyclization starting from thiourea and selenurea, resp., is developed.

NERY, A. C. S.; AVELLAR, M. M.; GOMES, C. R. B.; DE SOUZA, M. V. N.; VASCONCELOS, T. R. A.; Curr. Org. Synth. 12 (2015) 2, 140-149, http://dx.doi.org/10.2174/1570179411666141201201009 ; Inst. Tecnol. Farm.-Far Manguinhos, FioCruz-Fundacao Oswaldo Cruz, 21041 Rio de Janeiro, Brazil; Eng.) -S. Adam 30-287