c-di-AMP assists osmoadaptation by regulating the Listeria monocytogenes potassium transporters KimA and KtrCD Microbiology

Many bacteria and some archaea produce the second messenger cyclic diadenosine monophosphate (c-di-AMP). c-di-AMP controls the uptake of osmolytes in Firmicutes, including the human pathogen Listeria monocytogenes, making it essential for growth. c-di-AMP is known to directly regulate several potassium channels involved in osmolyte transport in species such as Bacillus subtilis and Streptococcus pneumoniae, but whether this same mechanism is involved in L. monocytogenes, or even whether similar ion channels were present, was not known. Here, we have identified and characterized the putative L. monocytogenes' potassium transporters KimA, KtrCD, and KdpABC. We demonstrate that Escherichia coli expressing KimA and KtrCD, but not KdpABC, transport potassium into the cell, and both KimA and KtrCD are inhibited by c-di-AMP in vivo. For KimA, c-di-AMP–dependent regulation requires the C-terminal domain. In vitro assays demonstrated that the dinucleotide binds to the cytoplasmic regulatory subunit KtrC and to the KdpD sensor kinase of the KdpDE two-component system, which in Staphylococcus aureus regulates the corresponding KdpABC transporter. Finally, we also show that S. aureus contains a homolog of KimA, which mediates potassium transport. Thus, the c-di-AMP–dependent control of systems involved in potassium homeostasis seems to be conserved in phylogenetically related bacteria. Surprisingly, the growth of an L. monocytogenes mutant lacking the c-di-AMP–synthesiz...
Source: Journal of Biological Chemistry - Category: Chemistry Authors: Tags: Microbiology Source Type: research

Related Links:

In this study, an effort was made for the biosynthesis of silver nanoparticle (AgNPs) having antimicrobial and non-cytotoxic activities with the help of microbial biosurfactant extracted from a novel Bacillus vallismortis strain MDU6 (Genbank accession no. MH382951) from petroleum oil logged soil sample in Dibrugarh, Assam. The isolate shows excellent potential for the production of biosurfactant by reducing the surface tension of diesel supplemented medium up to 56.57% only within 5 days. FTIR spectra of the crude biosurfactant show the presence of ʋCH2 (asymmetric stretching), ʋCH2 (symmetric stretching), ʋC=C (stretc...
Source: IET Nanobiotechnology - Category: Nanotechnology Source Type: research
h DH Abstract Human-milk-based probiotics play a major role in the early colonization and protection of infants against gastrointestinal infection. We investigated potential probiotics in human milk. Among 41 Lactic acid bacteria (LAB) strains, four strains showed high antimicrobial activity against Escherichia coli 0157:H7, Listeria monocytogenes ATCC 15313, Bacillus cereus ATCC 14576, Staphylococcus aureus ATCC 19095, and Helicobacter pylori. The selected LAB strains were tested in simulated gastrointestinal conditions for their survival. Four LAB strains showed high resistance to pepsin (82%-99%), bile with pan...
Source: International Journal of Biological Macromolecules - Category: Biochemistry Authors: Tags: Int J Biol Macromol Source Type: research
Publication date: 2019Source: Materials Today: Proceedings, Volume 19, Part 1Author(s): Α. Ntolia, N. Matisioudis, E. Triantafillou, G. Evangelopoulou, V. Karachristou, E. Rizos, T. Karamanidou, A. Tsouknidas, D. Papadopoulos, D. Tsipas, N. Michailidis, A. AggeliAbstractSilver nanoparticles (AgNPs) constitute a promising approach for the development of new antimicrobial systems. The major global concern about the emergence of bacterial strains resistant to widely used therapeutic agents for human infections has increased research for the discovery of new antimicrobial compounds as therapeutic alternatives. The aim of...
Source: Materials Today: Proceedings - Category: Materials Science Source Type: research
In conclusion, SCLP was a potential natural antimicrobial substance with strong antimicrobial activity, which may reduce the use of antibiotics or combat drug-resistant bacteria through synergistic combination with antibiotics. PMID: 31637496 [PubMed - as supplied by publisher]
Source: Applied Microbiology and Biotechnology - Category: Microbiology Authors: Tags: Appl Microbiol Biotechnol Source Type: research
Abstract Recently, oxo-biodegradable polymers have attracted much attention due to taking less time to break down after disposal in comparison to ordinary polymers. Polyvinyl alcohol/gelatin (PVA/G) nanocomposite films, containing ZnO, TiO2 or ZnO/TiO2 nanoparticles supported on 4A zeolite (4A z), are novel active packaging that can control the release of antimicrobial compounds. The present study assessed the efficacy of PVA/G nanocomposite films with 1.5% (w/w) ZnO/4A z (treatment 1), 1.5% (w/w) TiO2/4A z (treatment 2), or 1% (w/w) ZnO, TiO2/4A z (treatment 3) in controlling the microbial load and maintaining th...
Source: International Journal of Food Microbiology - Category: Food Science Authors: Tags: Int J Food Microbiol Source Type: research
During infection, bacterial pathogens successfully sense, respond and adapt to a myriad of harsh environments presented by the mammalian host. This exquisite level of adaptation requires a robust modulation of their physiological and metabolic features. Additionally, virulence determinants, which include host invasion, colonization and survival despite the host's immune responses and antimicrobial therapy, must be optimally orchestrated by the pathogen at all times during infection. This can only be achieved by tight coordination of gene expression. A large body of evidence implicate the prolific roles played by bacterial ...
Source: Frontiers in cellular and infection microbiology - Category: Microbiology Source Type: research
This study was conducted to determine the efficacy of UV-C irradiation for safety and quality of dried bay leaves. Cocktails of microorganisms of the same species were prepared and inoculated onto the leaves, which were thereafter subjected to UV-C irradiation. Results showed that all tested organisms, which included Escherichia coli O157:H7, Salmonella enterica, Pseudomonas aeruginosa, Listeria monocytogenes, and Staphylococcus aureus, exhibited inactivation behaviors in the irradiated leaves that are characterized by initial log-linear population decline, followed by inactivation tail. The Total Log Reductions in the org...
Source: LWT Food Science and Technology - Category: Food Science Source Type: research
Publication date: January 2020Source: LWT, Volume 117Author(s): Chantelle Human, Dalene de Beer, Marique Aucamp, Isa J. Marx, Christiaan J. Malherbe, Marinda Viljoen-Bloom, Marieta van der Rijst, Elizabeth JoubertAbstractGreen rooibos extract containing high levels of aspalathin, a dihydrochalcone antioxidant, and the carrier chitosan, both an antioxidant and antimicrobial agent, was used to produce a dual-purpose food ingredient powder by spray-drying for incorporation into processed meat products. Green rooibos extract was shown to inhibit growth of Escherichia coli, Staphylococcus aureus and Listeria monocytogenes, addi...
Source: LWT Food Science and Technology - Category: Food Science Source Type: research
This study explores the influence of functionalization process of cellulosic structure on its mechanical and comfort properties. Chitosan hydrogel has been synthetized and applied on cellulosic fabric to impart pH-sensitivity and antimicrobial behavior. The hydrogel bounded rate onto the surface was enhanced by a previous chemical activation of cotton fabric. Antimicrobial behavior was confirmed by investigation of the antibacterial activities against Escherichia coli, Listeria monocytogene and Staphylococcus aureus bacteria. The pH stimuli-responsiveness behavior was also confirmed and the pH-dependency swelling of the c...
Source: Carbohydrate Polymers - Category: Biomedical Science Source Type: research
Publication date: Available online 18 September 2019Source: Food BioscienceAuthor(s): Sarengaowa, Wenzhong Hu, Ke Feng, Zhilong Xiu, Aili Jiang, Ying LaoAbstractFresh-cut cantaloupe (Cucumis melo L.) is a popular food. However, the presence of foodborne pathogen on the cut surfaces leads to both spoilage and food poisoning of fresh-cut cantaloupe. The antibacterial effectiveness of an alginate-based edible coating (EC) containing thyme oil was evaluated against foodborne pathogens on fresh-cut cantaloupe samples. Cantaloupe samples were treated with alginate-based EC and alginate-based EC containing different concentration...
Source: Food Bioscience - Category: Food Science Source Type: research
More News: Chemistry | Gastroenteritis | Listeria | Men | Microbiology | Potassium | Staphylococcus Aureus