1
|
Prajapati B, Bernal-Cabas M, López-Álvarez M, Schaffer M, Bartel J, Rath H, Steil L, Becher D, Völker U, Mäder U, van Dijl JM. Double trouble: Bacillus depends on a functional Tat machinery to avoid severe oxidative stress and starvation upon entry into a NaCl-depleted environment. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1868:118914. [PMID: 33245978 DOI: 10.1016/j.bbamcr.2020.118914] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 11/08/2020] [Accepted: 11/20/2020] [Indexed: 11/17/2022]
Abstract
The widely conserved twin-arginine translocases (Tat) allow the transport of fully folded cofactor-containing proteins across biological membranes. In doing so, these translocases serve different biological functions ranging from energy conversion to cell division. In the Gram-positive soil bacterium Bacillus subtilis, the Tat machinery is essential for effective growth in media lacking iron or NaCl. It was previously shown that this phenomenon relates to the Tat-dependent export of the heme-containing peroxidase EfeB, which converts Fe2+ to Fe3+ at the expense of hydrogen peroxide. However, the reasons why the majority of tat mutant bacteria perish upon dilution in NaCl-deprived medium and how, after several hours, a sub-population adapts to this condition was unknown. Here we show that, upon growth in the absence of NaCl, the bacteria face two major problems, namely severe oxidative stress at the membrane and starvation leading to death. The tat mutant cells can overcome these challenges if they are fed with arginine, which implies that severe arginine depletion is a major cause of death and resumed arginine synthesis permits their survival. Altogether, our findings show that the Tat system of B. subtilis is needed to preclude severe oxidative stress and starvation upon sudden drops in the environmental Na+ concentration as caused by flooding or rain.
Collapse
Affiliation(s)
- Bimal Prajapati
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology, Groningen, the Netherlands
| | - Margarita Bernal-Cabas
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology, Groningen, the Netherlands
| | - Marina López-Álvarez
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology, Groningen, the Netherlands
| | - Marc Schaffer
- University Medicine Greifswald, Interfaculty Institute of Genetics and Functional Genomics, Department of Functional Genomics, Greifswald, Germany
| | - Jürgen Bartel
- University of Greifswald, Institute of Microbiology, Department of Microbial Proteomics, Greifswald, Germany
| | - Hermann Rath
- University Medicine Greifswald, Interfaculty Institute of Genetics and Functional Genomics, Department of Functional Genomics, Greifswald, Germany
| | - Leif Steil
- University Medicine Greifswald, Interfaculty Institute of Genetics and Functional Genomics, Department of Functional Genomics, Greifswald, Germany
| | - Dörte Becher
- University of Greifswald, Institute of Microbiology, Department of Microbial Proteomics, Greifswald, Germany
| | - Uwe Völker
- University Medicine Greifswald, Interfaculty Institute of Genetics and Functional Genomics, Department of Functional Genomics, Greifswald, Germany
| | - Ulrike Mäder
- University Medicine Greifswald, Interfaculty Institute of Genetics and Functional Genomics, Department of Functional Genomics, Greifswald, Germany.
| | - Jan Maarten van Dijl
- University of Groningen, University Medical Center Groningen, Department of Medical Microbiology, Groningen, the Netherlands.
| |
Collapse
|
2
|
Chiappe CS, Iurlina MO, Saiz AI. Effect of honey phenolic extract on biofilm formation by Pediococcus pentosaceus and Lactobacillus fermentum. Lebensm Wiss Technol 2020. [DOI: 10.1016/j.lwt.2020.109782] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
|
3
|
Zhao D, Shah NP. Effect of tea extract on lactic acid bacterial growth, their cell surface characteristics and isoflavone bioconversion during soymilk fermentation. Food Res Int 2014. [DOI: 10.1016/j.foodres.2014.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
|
5
|
Selvaraj S, Krishnaswamy S, Devashya V, Sethuraman S, Krishnan UM. Investigations on membrane perturbation by chrysin and its copper complex using self-assembled lipid bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:13374-13382. [PMID: 21923196 DOI: 10.1021/la2029356] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The mechanism of membrane interactions of most of the flavonoids in the presence of transition-metal ions is not well-understood. To understand this phenomenon, the present work aims to synthesize a chrysin-copper complex at room temperature and investigate its influence on the electrical characteristics of planar lipid bilayers. The chrysin-copper complex was characterized by various spectroscopic techniques and was found to have a metal/ligand ratio of 1:2 and of cationic nature. Its ability to inhibit 1,1'-diphenyl-2-picrylhydrazyl (DPPH) radicals was not significant at alkaline pH because of the involvement of the 5-hydroxy group in coordination with the copper ion compared to its parent flavonoid, chrysin (p < 0.05). The addition of different concentrations (20-100 μM) of chrysin and the chrysin-copper complex to lipid bilayers decreases the resistance, indicating a strong surface interaction and partial insertion into the bilayer near the lipid-water interface. The dose-dependent reduction in resistance as a result of the chrysin-copper complex is more pronounced in comparison to chrysin, implying that the bulkier and charged chrysin-copper complex displays greater ability to distort the lipid bilayer architecture. These conclusions were further confirmed by curcumin-loaded liposome permeabilization studies, where both chrysin and its Cu(II) complex increased the fluidity in a dose-dependent manner. However, the extent of fluidization by the chrysin-copper complex was nearly twice that of chrysin alone (p < 0.05). The implications of these surface interactions of chrysin and its copper complex on cell membranes were studied using a hypotonic hemolysis assay. Our results demonstrate that, at low concentrations (20 μM), the chrysin-copper complex exhibited twice the protection against hypotonic stress-induced membrane disruption when compared to chrysin. However, this stabilizing effect gradually decreased and became comparable to chrysin at higher concentrations. This biphasic behavior of the chrysin-copper complex could further be explored for therapeutic applications.
Collapse
Affiliation(s)
- Stalin Selvaraj
- Centre for Nanotechnology and Advanced Biomaterials (CeNTAB), School of Chemical and Biotechnology, SASTRA University, Thanjavur 613 401, Tamil Nadu, India
| | | | | | | | | |
Collapse
|