Violacein and biofilm production in Janthinobacterium lividum

Abstract

Aims: To analyse the environmental stimuli modulating violacein and biofilm production in Janthinobacterium lividum. Methods and Results: Violacein and biofilm production by J. lividum DSM1522T was assayed in different growth conditions. Our data suggest that violacein and biofilm production is controlled by the carbon source, being inhibited by glucose and enhanced by glycerol. J. lividum produced violacein also in the presence of different sub‐inhibitory concentrations of ampicillin. As opposite, the production of N‐acylhomoserine lactone(s), quorum sensing regulators was shown to be positively regulated by glucose. Moreover, violacein‐producing cultures of J. lividum showed higher CFU counts than violacein‐nonproducing ones. Conclusions: Taken together, our results suggest that violacein and biofilm production could be regulated by a common metabolic pathway and that violacein as well as biofilm could represent a response to environmental stresses and a key factor in the survival mechanisms of J. lividum. Significance and Impact of the Study: Although several recent studies disclosed a number of interesting biological properties of violacein, few data are reported on the physiologic function of violacein in J. lividum. This paper adds new information on the complex mechanisms allowing and regulating bacterial life in hostile environments.

Towards a Better Understanding of the Use of Probiotics for Preventing Chytridiomycosis in Panamanian Golden Frogs

“…In pure cultures of J. lividum, violacein production begins during the stationary phase of growth, when population densities are high (Pantanella et al 2007). In addition, violacein production requires the oxidation of tryptophan and is regulated by the carbon source available to the bacteria in the local habitat (Hoshino 2011;Pantanella et al 2007). Consequently, if tryptophan was present at low concentrations or if populations of J. lividum did not reach a stationary growth phase, violacein production would not have occurred.…”

Current in vitro assay to determine bacterial biofilm formation of clinical isolates

“…safranin or methylen blue. 15,16 The limitations of this method are related to the low reproducibility of the method, i.e. : the experimental condition of biofilm growth, the specific nature and concentration of the solvent and the elution time, which very are crucial steps.…”

Influence of Environmental Factors on the Production of Violacein Synthesized By Janthinobacterium lividum

“…Due to its biotechnological potential, numerous studies have been done indicating that Chromobacterium violaceum and Janthinobacterium lividum are primarily responsible for its synthesis [3][4][5]9,21,22]. Violacein has an indole derivative structure [8,15,17,18,21] characterized as C20-H13-N3-O3 [4,22,23]. The pigment is insoluble in water but soluble in alcohols (methanol, ethanol) and acetone.…”

“…Violacein is a purple pigment product of the secondary metabolism of bacteria, whose biological activities have been widely reported, including antimicrobial activity (antibacterial, antiviral, antiprotozoal and antifungal) [3,4,[6][7][8][9][10][11][12][13][14] anticancer activity [15][16][17][18][19] antioxidant activity [20] and recent studies also show insecticidal activity [5]. Due to its biotechnological potential, numerous studies have been done indicating that Chromobacterium violaceum and Janthinobacterium lividum are primarily responsible for its synthesis [3][4][5]9,21,22]. Violacein has an indole derivative structure [8,15,17,18,21] characterized as C20-H13-N3-O3 [4,22,23].…”

“…The pigment is insoluble in water but soluble in alcohols (methanol, ethanol) and acetone. The performance of the violacein biosynthesis pathway can be affected by different factors involved in the process [6,24], hence the nutritional requirements needed to increase the production of this metabolite have been widely studied [24][25][26], indicating the importance of controlling growth nutritional and environmental factors for the production of the pigment [22,[27][28][29][30].…”