Influence of Carvacrol and 1,8-Cineole on Cell Viability, Membrane Integrity, and Morphology of Aeromonas hydrophila Cultivated in a Vegetable-Based Broth

2015 ◽  
Vol 78 (2) ◽  
pp. 424-429 ◽  
Author(s):  
JOSSANA PEREIRA de SOUSA ◽  
KATARYNE ÁRABE RIMÁ de OLIVEIRA ◽  
REGINA CELIA BRESSAN QUEIROZ de FIGUEIREDO ◽  
EVANDRO LEITE de SOUZA
Keyword(s):  
Cell Viability ◽  
Membrane Permeability ◽  
Aeromonas Hydrophila ◽  
Membrane Integrity ◽  
Cell Membrane Permeability ◽  
Confocal Laser ◽  
Wall Structure ◽  
Bacterial Cells ◽  
Transmission Electron ◽  
Cytoplasmic Content

This study investigated the effects of carvacrol (CAR) and 1,8-cineole (CIN) alone (at the MIC) or in combination at subinhibitory amounts (both at 1/8 MIC) on the cell viability, membrane permeability, and morphology of Aeromonas hydrophila INCQS 7966 (A. hydrophila) cultivated in a vegetable-based broth. CAR and CIN alone or in combination severely affected the viability of the bacteria and caused dramatic changes in the cell membrane permeability, leading to cell death, as observed by confocal laser microscopy. Scanning and transmission electron microscopy images of bacterial cells exposed to CAR or CIN or the mixture of both compounds revealed severe changes in cell wall structure, rupture of the plasma membrane, shrinking of cells, condensation of cytoplasmic content, leakage of intracellular material, and cell collapse. These findings suggest that CAR and CIN alone or in combination at subinhibitory amounts could be applied to inhibit the growth of A. hydrophila in foods, particularly as sanitizing agents in vegetables.

scholarly journals Microbial Photoinactivation by Visible Light Results in Limited Loss of Membrane Integrity

Antibiotics ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 341
Author(s):  
Katharina Hoenes ◽  
Richard Bauer ◽  
Barbara Spellerberg ◽  
Martin Hessling
Keyword(s):  
Visible Light ◽  
Pseudomonas Fluorescens ◽  
Bacterial Cell ◽  
Bacterial Species ◽  
Membrane Integrity ◽  
Cell Lysis ◽  
Microbial Inactivation ◽  
Bacterial Cells ◽  
Resistance Development ◽  
Transmission Electron

Interest in visible light irradiation as a microbial inactivation method has widely increased due to multiple possible applications. Resistance development is considered unlikely, because of the multi-target mechanism, based on the induction of reactive oxygen species by wavelength specific photosensitizers. However, the affected targets are still not completely identified. We investigated membrane integrity with the fluorescence staining kit LIVE/DEAD® BacLight™ on a Gram positive and a Gram negative bacterial species, irradiating Staphylococcus carnosus and Pseudomonas fluorescens with 405 nm and 450 nm. To exclude the generation of viable but nonculturable (VBNC) bacterial cells, we applied an ATP test, measuring the loss of vitality. Pronounced uptake of propidium iodide was only observed in Pseudomonas fluorescens at 405 nm. Transmission electron micrographs revealed no obvious differences between irradiated samples and controls, especially no indication of an increased bacterial cell lysis could be observed. Based on our results and previous literature, we suggest that visible light photoinactivation does not lead to rapid bacterial cell lysis or disruption. However, functional loss of membrane integrity due to depolarization or inactivation of membrane proteins may occur. Decomposition of the bacterial envelope following cell death might be responsible for observations of intracellular component leakage.

scholarly journals Study on the Function of the Inositol Polyphosphate Kinases Kcs1 and Vip1 of Candida albicans in Energy Metabolism

2020 ◽  
Vol 11 ◽  
Author(s):  
Xueling Peng ◽  
Qilin Yu ◽  
Yingzheng Liu ◽  
Tianyu Ma ◽  
Mingchun Li
Keyword(s):  
Candida Albicans ◽  
Energy Metabolism ◽  
Cell Membrane ◽  
Cell Viability ◽  
Membrane Permeability ◽  
Cell Activity ◽  
Cell Membrane Permeability ◽  
Mitochondrial Activity ◽  
Inositol Polyphosphate ◽  
Growth Activity

In Saccharomyces cerevisiae, inositol polyphosphate kinase KCS1 but not VIP1 knockout is of great significance for maintaining cell viability, promoting glycolysis metabolism, and inducing mitochondrial damage. The functions of Candida albicans inositol polyphosphate kinases Kcs1 and Vip1 have not yet been studied. In this study, we found that the growth rate of C. albicans vip1Δ/Δ strain in glucose medium was reduced and the upregulation of glycolysis was accompanied by a decrease in mitochondrial activity, resulting in a large accumulation of lipid droplets, along with an increase in cell wall chitin and cell membrane permeability, eventually leading to cell death. Relieving intracellular glycolysis rate or increasing mitochondrial metabolism can reduce lipid droplet accumulation, causing a reduction in chitin content and cell membrane permeability. The growth activity and energy metabolism of the vip1Δ/Δ strains in a non-fermentable carbon source glycerol medium were not different from those of the wild-type strains, indicating that knocking out VIP1 did not cause mitochondria damage. Moreover, C. albicans KCS1 knockout did not affect cell activity and energy metabolism. Thus, in C. albicans, Vip1 is more important than Kcs1 in regulating cell viability and energy metabolism.

Synergistic effect of cinnamaldehyde on the thermal inactivation of Listeria monocytogenes in ground pork

2019 ◽  
Vol 26 (1) ◽  
pp. 28-37 ◽  
Author(s):  
Yuexia Wang ◽  
Xiaoyan Li ◽  
Yangliu Lu ◽  
Jianan Wang ◽  
Biao Suo
Keyword(s):  
Listeria Monocytogenes ◽  
Thermal Inactivation ◽  
Meat Product ◽  
Membrane Integrity ◽  
Weibull Model ◽  
Mathematical Tool ◽  
Membrane Rupture ◽  
Transmission Electron ◽  
Ground Pork ◽  
Cytoplasmic Content

The aim of this study was to statistically evaluate the effect of a naturally food-derived cinnamaldehyde on the thermal inactivation of Listeria monocytogenes in ground pork. This study combined four concentrations of cinnamaldehyde (0, 0.1, 0.5, and 1.0% vol/wt) and four temperatures (55, 60, 65, and 70 ℃) to predict the thermal inactivation curves of L. monocytogenes. The Weibull model successfully described the primary thermal inactivation using the Integrated Pathogen Modeling Program. These results statistically proposed that the cinnamaldehyde supplementation in ground pork attenuates the thermo-tolerance of L. monocytogenes. The time for achieving a 5-log10 reduction of L. monocytogenes declined from 28.14 to 17.35 min at 55 ℃ when the ground pork sample was supplemented by 1% cinnamaldehyde, while the time declined from 1.95 to 0.34 min at 70 ℃. Thereafter, based on the 5.0-log10 lethality, secondary models were fitted by a selected polynomial model. The transmission electron microscopy revealed that cinnamaldehyde causes serious damage to membrane integrity and increases the occurrence of cell membrane rupture and leakage of cytoplasmic content under thermal treatment. Our model represents a mathematical tool that will help meat-product manufacturers to improve the efficacy of thermal processing ground pork supplemented with cinnamaldehyde.

Changes of Cell Membrane Permeability Induced by DMSO and Ethanol in Suspension Cultures of Taxus Cuspidata

2011 ◽  
Vol 236-238 ◽  
pp. 942-948 ◽  
Author(s):  
Xue Qing Wang ◽  
Yin Jin Yuan ◽  
Jin Chuan Li ◽  
Chen Chen
Keyword(s):  
Cell Membrane ◽  
Membrane Permeability ◽  
Membrane Integrity ◽  
Suspension Cultures ◽  
Cell Membrane Permeability ◽  
Taxus Cuspidata ◽  
Extracellular Medium ◽  
Cell Membrane Integrity ◽  
Long Time ◽  
Malonyl Dialdehyde

The changes of cell membrane permeability caused by dimethyl sulphoxide (DMSO) and ethanol, two commonly used solvents in study of water-insoluble elicitors, were investigated in suspension cultures of Taxus cuspidata. The extracellular medium became alkalinized in the case of DMSO while the medium pH fluctuated upon the addition of ethanol. When the content of DMSO or ethanol was larger than 2% (v/v), the concentration of intracellular malonyl dialdehyde (MDA) increased remarkably at day 5 compared to that of the control, while that of the extracellular MDA less changed at a DMSO content of below 2% (v/v) and increased rapidly within 15 min at a DMSO content of 4% (v/v). The electrical conductivity (EC) decreased slightly when DMSO content was below 2% (v/v) but increased markedly at day 5 when DMSO content reached 4% (v/v). EC less varied when the content of ethanol was below 0.4% (v/v) but changed obviously when the ethanol content was larger than 1% (v/v). The cell membrane integrity hardly broke in the case of small concentration of DMSO (below 1%, v/v), but the presence of even small amount of ethanol (0.4%, v/v) caused cell membrane integrity lost partly, especially long time contact. It is thus concluded that DMSO is a more suitable solvent for water-insoluble elicitors compared to ethanol especially at low concentration levels.

Chemical Composition, Antibacterial Activity, and Mechanism of Action of the Essential Oil from Amomum kravanh

2014 ◽  
Vol 77 (10) ◽  
pp. 1740-1746 ◽  
Author(s):  
WEN-RUI DIAO ◽  
LIANG-LIANG ZHANG ◽  
SAI-SAI FENG ◽  
JIAN-GUO XU
Keyword(s):  
Antibacterial Activity ◽  
Chemical Composition ◽  
Essential Oil ◽  
Cell Membrane ◽  
Membrane Permeability ◽  
Foodborne Pathogens ◽  
Cell Membrane Permeability ◽  
Gas Chromatography Mass Spectrometry ◽  
E Coli ◽  
Transmission Electron

Amomum kravanh is widely cultivated and used as a culinary spice. In this work, the chemical composition of the essential oil obtained by hydrodistillation of A. kravanh fruits was analyzed by gas chromatography–mass spectrometry, and 34 components were identified. 1,8-Cineole (68.42%) was found to be the major component, followed by α-pinene (5.71%), α-terpinene (2.63%), and β-pinene (2.41%). The results of antibacterial tests showed that the sensitivities to the essential oil of different foodborne pathogens tested were different based on the Oxford cup method, MIC, and MBC assays, and the essential oil exhibited the best antibacterial activity against Bacillus subtilis, a gram-positive bacterium, and Escherichia coli, a gram-negative bacterium. Growth in the presence of Amomum kravanh at the MIC, as measured by monitoring optical density over time, demonstrated that the essential oil was bacteriostatic after 12 h to both B. subtilis and E. coli. Observations of cell membrane permeability, cell constituent release assay, and transmission electron microscopy indicated that this essential oil may disrupt the cell wall and cell membrane permeability, leading to leakage of intracellular constituents in both B. subtilis and E. coli.

Antimicrobial Effects of 7,8-Dihydroxy-6-Methoxycoumarin and 7-Hydroxy-6-Methoxycoumarin Analogues against Foodborne Pathogens and the Antimicrobial Mechanisms Associated with Membrane Permeability

2017 ◽  
Vol 80 (11) ◽  
pp. 1784-1790 ◽  
Author(s):  
Ji-Yeon Yang ◽  
Jun-Hwan Park ◽  
Myung-Ji Lee ◽  
Ji-Hoon Lee ◽  
Hoi-Seon Lee
Keyword(s):  
Antimicrobial Activity ◽  
Cell Membrane ◽  
Membrane Permeability ◽  
Foodborne Pathogens ◽  
Antimicrobial Agents ◽  
Functional Group ◽  
Membrane Integrity ◽  
Cell Membrane Permeability ◽  
Antimicrobial Effects ◽  
Structural Analogues

ABSTRACT The antimicrobial effects of 7,8-dihydroxy-6-methoxycoumarin and 7-hydroxy-6-methoxycoumarin isolated from Fraxinus rhynchophylla bark and of their structural analogues were determined in an attempt to develop natural antimicrobial agents against the foodborne pathogens Escherichia coli, Bacillus cereus, Staphylococcus intermedius, and Listeria monocytogenes. To elucidate the relationship between structure and antimicrobial activity for the coumarin analogues, isolated constituents and their structural analogues were evaluated against foodborne pathogens. Based on the culture plate inhibition zones and MICs, 6,7-dimethoxycoumarin, 7,8-dihydroxy-6-methoxycoumarin, 7-hydroxy-6-methoxycoumarin, and 7-methoxycoumarin, containing a methoxy functional group on the coumarin skeleton, had the notable antimicrobial activity against foodborne pathogens. However, 7-hydroxycoumarin and 6,7-dihydroxycoumarin, which contained a hydroxyl functional group on the coumarin skeleton, had no antimicrobial activity against these pathogens. An increase in cell membrane permeability was confirmed by electron microscopy observations, and release of extracellular ATP and cell constituents followed treatment with the ethyl acetate fraction of F. rhynchophylla extract. These findings indicate that F. rhynchophylla extract and coumarin analogues have potential for use as antimicrobial agents against foodborne pathogens and that the antimicrobial mechanisms are associated with the loss of cell membrane integrity.

Alternative to Nitrites as Antibacterial Agents Against Clostridium sporogenes

2018 ◽  
Vol 17 (3) ◽  
pp. 242-248
Author(s):  
Zhang Zhi-Guo ◽  
Sun Di ◽  
Wang Mei-Lin
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Normal Growth ◽  
Food Preservation ◽  
Cell Membrane Permeability ◽  
Nitroso Compounds ◽  
Wall Structure ◽  
Ion Leakage ◽  
Bacterial Cells ◽  
Clostridium Sporogenes

Microbial spoilage is one of the key challenges to food preservation and safety. Sodium nitrite, the commonly used antibacterial, is associated with the generation of nitroso compounds known to impose a number of health risks including cancer. In this article, we report a comparison of a number of food-grade antibacterials, not known to generate nitroso compounds, for the inhibition of Clostridium sporogenes. These include e-poly-lysine, potassium cinnamate, chitosan, and glycerol monolaurate. We examined the effects of these agents alone and in combination on cell morphology, cell wall, cell membrane permeability, and bacterial proteins of C. sporogenes. The results show that these agents primarily act to inhibit C. sporogenes growth during log phase. Further analysis with flow cytometry and scanning electron microscopy revealed that the compound can induce changes to the morphology of C. sporogenes cells and, more significantly, to the internal structure of the cells. Treatment of C. sporogenes with the compound inhibited the normal growth of bacterial cells by damaging their wall structure and increasing their wall permeability. The changing pattern of electric conductivity indicated that the compound destroyed cytoplasmic membranes and resulted in ion leakage. Sodium dodecyl sulfate polyacrylamide gel electrophoresis analysis of soluble proteins concluded that the compound can destroy bacterial cells by altering their proteins.

scholarly journals The Effect of Saturated Fatty Acids on Methanogenesis and Cell Viability ofMethanobrevibacter ruminantium

Archaea ◽  
2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Xuan Zhou ◽  
Leo Meile ◽  
Michael Kreuzer ◽  
Johanna O. Zeitz
Keyword(s):  
Fatty Acids ◽  
Cell Membrane ◽  
Cell Viability ◽  
Membrane Permeability ◽  
Production Rate ◽  
Methane Production ◽  
Saturated Fatty Acids ◽  
Cell Membrane Permeability ◽  
Potassium Efflux ◽  
Methane Production Rate

Saturated fatty acids (SFAs) are known to suppress ruminal methanogenesis, but the underlying mechanisms are not well known. In the present study, inhibition of methane formation, cell membrane permeability (potassium efflux), and survival rate (LIVE/DEAD staining) of pure ruminalMethanobrevibacter ruminantium(DSM 1093) cell suspensions were tested for a number of SFAs. Methane production rate was not influenced by low concentrations of lauric (C12; 1 μg/mL), myristic (C14; 1 and 5 μg/mL), or palmitic (C16; 3 and 5 μg/mL) acids, while higher concentrations were inhibitory. C12and C14were most inhibitory. Stearic acid (C18), tested at 10–80 μg/mL and ineffective at 37°C, decreased methane production rate by half or more at 50°C and ≥50 μg/mL. Potassium efflux was triggered by SFAs (C12= C14> C16> C18= control), corroborating data on methane inhibition. Moreover, the exposure to C12and C14decreased cell viability to close to zero, while 40% of control cells remained alive after 24 h. Generally, tested SFAs inhibited methanogenesis, increased cell membrane permeability, and decreased survival ofM. ruminantiumin a dose- and time-dependent way. These results give new insights into how the methane suppressing effect of SFAs could be mediated in methanogens.

scholarly journals Mycoplasma suis Invades Porcine Erythrocytes

2008 ◽  
Vol 77 (2) ◽  
pp. 576-584 ◽  
Author(s):  
K. Groebel ◽  
K. Hoelzle ◽  
M. M. Wittenbrink ◽  
U. Ziegler ◽  
L. E. Hoelzle
Keyword(s):  
Laser Scanning ◽  
Fluorescent Labeling ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Bacterial Cells ◽  
Mycoplasma Suis ◽  
Transmission Electron ◽  
Blood Smears ◽  
Hemotrophic Mycoplasma ◽  
First Time

ABSTRACT Mycoplasma suis belongs to the hemotrophic mycoplasma group and causes infectious anemia in pigs. According to the present state of knowledge, this organism adheres to the surface of erythrocytes but does not invade them. We found a novel M. suis isolate that caused severe anemia in pigs with a fatal disease course. Interestingly, only marginal numbers of the bacteria were visible on and between the erythrocytes in acridine orange-stained blood smears for acutely diseased pigs, whereas very high loads of M. suis were detected in the same blood samples by quantitative PCR. These findings indicated that M. suis is capable of invading erythrocytes. By use of fluorescent labeling of M. suis and examination by confocal laser scanning microscopy, as well as scanning and transmission electron microscopy, we proved that the localization of M. suis was intracellular. This organism invades erythrocytes in an endocytosis-like process and is initially surrounded by two membranes, and it was also found floating freely in the cytoplasm. In conclusion, we were able to prove for the first time that a member of the hemotrophic mycoplasma group is able to invade the erythrocytes of its host. Such colonization should protect the bacterial cells from the host's immune response and hamper antibiotic treatment. In addition, an intracellular life cycle may explain the chronic nature of hemotrophic mycoplasma infections and should serve as the foundation for novel strategies in hemotrophic mycoplasma research (e.g., treatment or prophylaxis).

Effect of CuO Nanoparticles on the Cell Membrane Permeability of A549 and its Exclusion

2011 ◽  
Vol 343-344 ◽  
pp. 77-80
Author(s):  
Xiao Yan Xie ◽  
Li Li Xu ◽  
Dong Mei Gao
Keyword(s):  
Cell Membrane ◽  
Membrane Permeability ◽  
Membrane Integrity ◽  
Cuo Nanoparticles ◽  
Cell Membrane Permeability ◽  
Lung Cells ◽  
Cuo Nps ◽  
Dose Dependent ◽  
Human A549 ◽  
A549 Lung

This study was conducted to explore the effect of CuO nanoparticles (NPs) on the cell membrane permeability and its exclusion from cells. Human A549 lung cells were exposed to 5mg/L and 15mg/L CuO NPs. Cell membrane permeability was evaluated in 2h and 4h. After 4 hours exposure, the membrane was damaged. Exclusion of copper from cells after 24h exposure with 5mg/L and 15 mg/L CuO NPs are time and dose dependent. And the cell viability was resumed gradually. It is concluded that CuO NPs could induce cytotoxicity, and destroy the membrane integrity. One detoxify mechanism was the exclusion of excessive copper from cells themselves.

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