Transcription Analysis of a Lantibiotic Gene Cluster from Bifidobacterium longum DJO10A

Abstract

Bifidobacterium longum DJO10A was previously demonstrated to produce a lantibiotic, but only during growth on agar media. To evaluate the feasibility of production of this lantibiotic in broth media, a transcription analysis of the lanA gene was undertaken. Comparative microarray analysis of broth and agar cultures of B. longum DJO10A revealed that the lantibiotic production, modification, transport/peptidase, and immunity genes were significantly upregulated in agar cultures, while the two-component regulatory genes were expressed equally under both conditions. This suggested that the signal transduction regulatory system should function in broth cultures. Real-time PCR and Northern hybridization confirmed that lanA gene expression was significantly repressed in broth cultures. A crude lantibiotic preparation from an agar-grown culture was obtained, and its antimicrobial spectrum analysis revealed a broad inhibition range. Addition of this extract to broth cultures of B. longum DJO10A induced lanA gene expression in a dose-dependent fashion. Subinoculation using >10% of an induced broth culture maintained lanA expression. The expression of lanA was log-phase specific, being significantly downregulated in stationary phase. Transcription start analysis of lanA revealed a 284-bp 5 untranslated region, which was proposed to be involved in repression of transcription, while an inverted repeat structure located at bp ؊75 relative to the transcription start was strategically located to likely function as a binding site for the two-component response regulator. Understanding the transcription regulation of this lanA gene is the first step toward enabling production of this novel and potentially interesting lantibiotic in broth cultures.

Discovery of a novel lantibiotic nisin O from Blautia obeum A2-162, isolated from the human gastrointestinal tract

“…The yield of nisin H in culture supernatants from gut bacterium S. hyointestinalis was also found to be low compared to that of nisin A [12]. Production of mutacin I, the Bifidobacterium longum DJO10A lantibiotic and the two component haloduracin from Bacillus halodurans was also only seen on solid media [66,68,69], and it has been proposed that the dense colonization necessary for mutacin I production is reminiscent of a biofilm condition [66]. A putative lantibiotic cluster in Streptococcus pneumoniae has recently been shown to be controlled by quorum sensing, with expression being induced at high cell densities and depending on the carbon source [70].…”

Produção de bacteriocina por Bifidobacterium lactis a partir de soro de leite

“…Although the lantibiotic activity (160 AU/mL) was low, it was sufficient for microtiter plate-based experiments (Lee et al, 2011).…”

“…Further investigations established that bifidin I has a broad activity spectrum, including Gram-positive bacteria such as Streptococcus, Staphylococcus and Clostridium, and Gram-negative ones such as Salmonella, Shigella and E. coli (Cheikhyoussef et al, 2009b). Bisin was found to be effective against several indicator strains of Streptococcus thermophilus, Bacillus subtilis, Serratia marcescens and S. aureus, among others (Lee et al, 2008(Lee et al, , 2011.…”

“…Bifidin from B. bifidum NCDC 1452 was optimally produced at pH 4.8, displayed maximal inhibitory potential between 4.8 and 5.5, and was stable even after exposure to 100°C for 30 min Lee et al (2011) a Prior to leader cleavage. (Anand et al, 1984(Anand et al, , 1985.…”

“…Lee et al (2008) described the production of the Class I lantibiotic bisin by B. longum DJO10A, which was found to be effective against both Gram-positive and Gram-negative bacteria. Bisin is encoded by a typical lantibiotic-associated gene cluster consisting of genes encoding, in two-component signal transduction system (lanR2 and lanK), a lantibiotic prepeptide (lanA), a lantibiotic response regulator (lanR1), lantibiotic modification enzymes (lanD and lanM), a lantibiotic immunity protein (lanI) and a lantibiotic transporter with predicted protease activity (lanT) (Lee et al, 2008(Lee et al, , 2011. Its production was detected when the producing strain was grown on agar, but not in broth due to repression of lanA transcription; however, the lantibiotic, when added to broth (at 160 AU antimicrobial activity), acted as an induction factor improving the production.…”