scholarly journals Mechanisms of transforming DNA uptake to the periplasm of Bacillus subtilis

2021 ◽  
Author(s):  
Jeanette Hahn ◽  
Micaela DeSantis ◽  
David Dubnau
Keyword(s):  
Bacillus Subtilis ◽  
Virulence Genes ◽  
Bacterial Species ◽  
Epifluorescence Microscopy ◽  
Cellular Distribution ◽  
Dna Uptake ◽  
Early Step ◽  
Ratchet Mechanism ◽  
New Evidence

ABSTRACTWe demonstrate here that the acquisition of DNAase resistance by transforming DNA, often assumed to indicate transport to the cytoplasm, actually reflects uptake to the periplasm, requiring a re-evaluation of conclusions about the roles of several proteins in transformation. The new evidence suggests that the transformation pilus is needed for DNA binding to the cell surface near the cell poles and for the initiation of uptake. The cellular distribution of the membrane-anchored ComEA of B. subtilis does not noticeably change during DNA uptake as does the unanchored ComEA of Vibrio and Neisseria. Instead, our evidence suggests that ComEA stabilizes the attachment of transforming DNA at localized regions in the periplasm and then mediates uptake, probably by a Brownian ratchet mechanism. Following that, the DNA is transferred to periplasmic portions of the channel protein ComEC, which plays a previously unsuspected role in uptake to the periplasm. We show that the transformation endonuclease NucA also facilitates uptake to the periplasm and that the previously demonstrated role of ComFA in the acquisition of DNAase resistance actually derives from the instability of ComGA when ComFA is deleted. These results prompt a new understanding of the early stages of DNA uptake for transformation.IMPORTANCETransformation is a widely distributed mechanism of bacterial horizontal gene transfer that plays a role in the spread of antibiotic resistance and virulence genes and more generally in evolution. Although transformation was discovered nearly a century ago and most, if not all of the proteins required have been identified in several bacterial species, much remains poorly understood about the molecular mechanism of DNA uptake. This study uses epifluorescence microscopy to investigate the passage of labeled DNA into the compartment between the cell wall and the cell membrane of Bacillus subtilis, a necessary early step in transformation. The roles of individual proteins in this process are identified, and their modes of action are clarified.

scholarly journals Mechanisms of Transforming DNA Uptake to the Periplasm of Bacillus subtilis

mBio ◽  
2021 ◽  
Author(s):  
Jeanette Hahn ◽  
Micaela DeSantis ◽  
David Dubnau
Keyword(s):  
Antibiotic Resistance ◽  
Bacillus Subtilis ◽  
Gene Transfer ◽  
Horizontal Gene Transfer ◽  
Molecular Mechanism ◽  
Virulence Genes ◽  
Bacterial Species ◽  
Dna Uptake

Transformation is a widely distributed mechanism of bacterial horizontal gene transfer that plays a role in the spread of antibiotic resistance and virulence genes and more generally in evolution. Although transformation was discovered nearly a century ago and most, if not all the proteins required have been identified in several bacterial species, much remains poorly understood about the molecular mechanism of DNA uptake.

Role of ComFA in controlling the DNA uptake rate during transformation of competent Bacillus subtilis

2011 ◽  
Vol 111 (6) ◽  
pp. 618-623 ◽  
Author(s):  
Masaomi Takeno ◽  
Hisataka Taguchi ◽  
Takashi Akamatsu
Keyword(s):  
Bacillus Subtilis ◽  
Uptake Rate ◽  
Dna Uptake

Role of ComEA in DNA uptake during transformation of competent Bacillus subtilis

2012 ◽  
Vol 113 (6) ◽  
pp. 689-693 ◽  
Author(s):  
Masaomi Takeno ◽  
Hisataka Taguchi ◽  
Takashi Akamatsu
Keyword(s):  
Bacillus Subtilis ◽  
Dna Uptake

scholarly journals Antibacterial and antibiofilm properties of Phlomis and Stachys species

2020 ◽  
Vol 49 (2) ◽  
pp. 257-263
Author(s):  
Aynur Aybey
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antibacterial Activity ◽  
Bacillus Subtilis ◽  
Ethyl Acetate ◽  
Bacterial Species ◽  
Bacterial Strains ◽  
Methanol Extracts ◽  
Good Antibacterial Activity ◽  
Antibiofilm Agents

The ethyl acetate and methanol extracts of Phlomis pungens var. pungens, P. nissolii, P. armeniaca and Stachys byzantina, S. cretica L. subsp. mersiaea and S. cretica L. subsp. Smyrnaea were evaluated for their antibacterial and antibiofilm activities. Five bacterial species were used are Bacillus subtilis, Pseudomonas aeruginosa, Shigella sonnei, Salmonella typhimurium and Yersinia enterocolitica. The ethyl acetate and methanol extracts of plant species showed good antibacterial activity against all bacterial strains. More significantly, ethylacetate and methanol extracts of all Phlomis species were found to be more effective on degredation of mature biofilm against all used bacterial strains than extracts of Stachys species. The findings of the present study highlight the promising role of Phlomis and Stachys extracts as new lead structures in the search for novel antibacterial and antibiofilm agents.

Investigation on the antibacterial activity of electronic cigarette liquids (ECLs): a proof of concept study

2020 ◽  
Vol 21 ◽  
Author(s):  
Virginia Fuochi ◽  
Massimo Caruso ◽  
Rosalia Emma ◽  
Aldo Stivala ◽  
Riccardo Polosa ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Bacterial Species ◽  
A549 Cells ◽  
Bactericidal Effect ◽  
Minimal Bactericidal Concentration ◽  
Viability Assay ◽  
Dependent Inhibition ◽  
Dose Dependent Inhibition ◽  
Dose Dependent

Background: The key ingredients of e-cigarettes liquid are commonly propane-1,2-diol (also called propylene glycol) and propane-1,2,3-triol (vegetal glycerol) and their antimicrobial effects are already established. The nicotine and flavors which are often present in e-liquids can interfere with the growth of some microorganisms. Objective: The effect of the combining these elements in e-liquids is unknown. The aim of the study was to investigate the possible effects of these liquids on bacterial growth in the presence or absence of nicotine and flavors. Methods: Susceptibilities of pathogenic strains (Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis and Sarcina lutea) were studied by means of a multidisciplinary approach. Cell viability and antioxidant assays were also evaluated. Results: All e-liquids investigated showed antibacterial activity against at least one pathogenic strain. A higher activity was correlated to the presence of flavors and nicotine. Discussion: In most cases the value of minimal bactericidal concentration is equal to the value of minimal inhibitory concentration showing that these substances have a bactericidal effect. This effect was observed in concentrations up to 6.25% v/v. Antioxidant activity was also correlated to presence of flavors. Over time, the viability assay in human epithelial lung A549 cells showed a dose-dependent inhibition of cell growth. Conclusion: Our results have shown that flavors considerably enhance the antibacterial activity of propane-1,2-diol and propane-1,2,3-triol. This study provides important evidence that should be taken into consideration in further investigative approaches, to clarify the different sensitivity of the various bacterial species to e-liquids, including the respiratory microbiota, to highlight the possible role of flavors and nicotine.

Defensive Role of Plant-Derived Secondary Metabolites: Indole and Its’ Derivatives

2020 ◽  
Vol 9 (2) ◽  
pp. 78-88
Author(s):  
Mulugeta Mulat ◽  
Raksha Anand ◽  
Fazlurrahman Khan
Keyword(s):  
Biofilm Formation ◽  
Growth And Development ◽  
Functional Role ◽  
Plant Pathogens ◽  
Bacterial Species ◽  
Indole Derivatives ◽  
Resistance Level ◽  
Defensive Role ◽  
Insect Attack

The diversity of indole concerning its production and functional role has increased in both prokaryotic and eukaryotic systems. The bacterial species produce indole and use it as a signaling molecule at interspecies, intraspecies, and even at an interkingdom level for controlling the capability of drug resistance, level of virulence, and biofilm formation. Numerous indole derivatives have been found to play an important role in the different systems and are reported to occur in various bacteria, plants, human, and plant pathogens. Indole and its derivatives have been recognized for a defensive role against pests and insects in the plant kingdom. These indole derivatives are produced as a result of the breakdown of glucosinolate products at the time of insect attack or physical damages. Apart from the defensive role of these products, in plants, they also exhibit several other secondary responses that may contribute directly or indirectly to the growth and development. The present review summarized recent signs of progress on the functional properties of indole and its derivatives in different plant systems. The molecular mechanism involved in the defensive role played by indole as well as its’ derivative in the plants has also been explained. Furthermore, the perspectives of indole and its derivatives (natural or synthetic) in understanding the involvement of these compounds in diverse plants have also been discussed.

scholarly journals Polyhydroxyalkanoate Nanoparticles for Pulmonary Drug Delivery: Interaction with Lung Surfactant

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1482
Author(s):  
Olga Cañadas ◽  
Andrea García-García ◽  
M. Auxiliadora Prieto ◽  
Jesús Pérez-Gil
Keyword(s):  
Drug Delivery ◽  
Drug Delivery Systems ◽  
Bacterial Species ◽  
High Surface ◽  
Lung Surfactant ◽  
Delivery Systems ◽  
Pulmonary Drug Delivery ◽  
Epifluorescence Microscopy ◽  
Energy Storage Materials ◽  
The Stability

Polyhydroxyalkanoates (PHA) are polyesters produced intracellularly by many bacterial species as energy storage materials, which are used in biomedical applications, including drug delivery systems, due to their biocompatibility and biodegradability. In this study, we evaluated the potential application of this nanomaterial as a basis of inhaled drug delivery systems. To that end, we assessed the possible interaction between PHA nanoparticles (NPs) and pulmonary surfactant using dynamic light scattering, Langmuir balances, and epifluorescence microscopy. Our results demonstrate that NPs deposited onto preformed monolayers of DPPC or DPPC/POPG bind these surfactant lipids. This interaction facilitated the translocation of the nanomaterial towards the aqueous subphase, with the subsequent loss of lipid from the interface. NPs that remained at the interface associated with liquid expanded (LE)/tilted condensed (TC) phase boundaries, decreasing the size of condensed domains and promoting the intermixing of TC and LE phases at submicroscopic scale. This provided the stability necessary for attaining high surface pressures upon compression, countering the destabilization induced by lipid loss. These effects were observed only for high NP loads, suggesting a limit for the use of these NPs in pulmonary drug delivery.

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