Analysis of a bac operon-silenced strain suggests pleiotropic effects of bacilysin in Bacillus subtilis

Abstract

Bacilysin, as the simplest peptide antibiotic made up of only L-alanine and L-anticapsin, is produced and excreted by Bacillus subtilis under the control of quorum sensing. We analyzed bacilysin-nonproducing strain OGU1 which was obtained by bacA-targeted pMutin T3 insertion into the parental strain genome resulting in a genomic organization (bacA ::lacZ::erm::bacABCDEF) to form an IPTG-inducible bac operon. Although IPTG induction provided 3-to 5-fold increment in the transcription of bac operon genes, no bacilysin activity was detectable in bioassays and inability of the OGU1 to form bacilysin was confirmed by UPLC-mass spectrometry analysis. Phenotypic analyses revealed the deficiencies in OGU1 with respect to colony pigmentation, spore coat proteins, spore resistance and germination, which could be rescued by external addition of bacilysin concentrate into its cultures. 2DE MALDI-TOF/MS and nanoLC-MS/MS were used as complementary approaches to compare cytosolic proteomes of OGU1. 2-DE identified 159 differentially expressed proteins corresponding to 121 distinct ORFs. In nanoLC-MS/MS, 76 proteins were differentially expressed in OGU1. Quantitative transcript analyses of selected genes validated the proteomic findings. Overall, the results pointed to the impact of bacilysin on expression of certain proteins of sporulation and morphogenesis; the members of mother cell compartment-specific σ E and σ K regulons in particular, quorum sensing and two component-global regulatory systems, peptide transport, stress response as well as CodY-and ScoCregulated proteins.

Signatures of kin selection in a natural population of the bacteria Bacillus subtilis

“…Fourth, we looked at toxins. For the cooperative genes, we used bacilycin, which is a secreted antimicrobial peptide that is active against a range of bacteria ( Ertekin et al, 2020 ). Because bacilycin can diffuse through the environment, it likely has cooperative fitness effects on others.…”

Isolation, identification, and genome of a Bacillus velezensis JIN4 exhibiting biocontrol activity against kiwifruit bacterial canker

“…Bacillibactin enhances the bioavailability of iron in the environment, promotes plant growth, and reduces pathogen abundance by competing for iron ions (Abergel et al, 2009;Lee et al, 2011;Nithyapriya et al, 2021). The cell walls of bacteria and fungi can be damaged by Baclysin (Wu et al, 2015;Ertekin et al, 2020). There are also two compounds, macrolactin H and mersacidin, whose functions are unknown.…”

Çekte Düzenleme Tarihi ve Düzenleme Tarihinde Tahrifat Yapılmasının Sonuçları

“…Çekin düzenleme tarihinde tahrifat eylemini gerçekleştirmek suretiyle muhatap bankanın çeki hak sahibi olmayan bir kimseye ödemesine neden olan kişi doğan zarardan dolayı Türk Borçlar Kanunu'nun 49 uncu maddesindeki haksız fiil hükümleri çerçevesinde sorumlu olur 99 . Tahrif edilmiş çek hakkında Türk Ticaret Kanunu'nun 812 nci maddesi uyarınca muhatap bankanın kusursuz sorumluluğu bulunuyor olsa da, çekin düzenleme tarihinde tahrifat yapan kimsenin de uğranılan zarardan dolayı sorumlu olduğu tereddütsüz kabul edilmelidir 100 . Tahrifatı gerçekleştiren kişi çeki haksız bir şekilde ele geçiren üçüncü kişi olabileceği gibi lehtar, ciranta veya meşru hamil de olabilir 101 .…”