scholarly journals Photodynamic Inactivation Using Natural Bioactive Compound Prevents and Disrupts the Biofilm Produced by Staphylococcus saprophyticus

Molecules ◽  
2021 ◽  
Vol 26 (16) ◽  
pp. 4713
Author(s):  
Wei Yang ◽  
Ziyuan Wang ◽  
Qing Li ◽  
Yating Jia ◽  
Shuimiao Song ◽  
...  
Keyword(s):  
Membrane Damage ◽  
Membrane Integrity ◽  
Bioactive Compound ◽  
Morphological Alteration ◽  
Photodynamic Inactivation ◽  
Limited Information ◽  
Staphylococcus Saprophyticus ◽  
Food Borne ◽  
Cellular Metabolic Activity ◽  
Structural Injury

Staphylococcus saprophyticus, the food-borne bacteria present in dairy products, ready-to-eat food and environmental sources, has been reported with antibiotic resistance, raising concerns about food microbial safety. The antimicrobial resistance of S. saprophyticus requires the development of new strategies. Light- and photosensitizer-based antimicrobial photodynamic inactivation (PDI) is a promising approach to control microbial contamination, whereas there is limited information regarding the effectiveness of PDI on S. saprophyticus biofilm control. In this study, PDI mediated by natural bioactive compound (curcumin) associated with LED was evaluated for its potential to prevent and disrupt S. saprophyticus biofilms. Biofilms were treated with curcumin (50, 100, 200 µM) and LED fluence (4.32 J/cm2, 8.64 J/cm2, 17.28 J/cm2). Control groups included samples treated only with curcumin or light, and samples received neither curcumin nor light. The action was examined on biofilm mass, viability, cellular metabolic activity and cytoplasmic membrane integrity. PDI using curcumin associated with LED exhibited significant antibiofilm activities, inducing biofilm prevention and removal, metabolic inactivation, intracellular membrane damage and cell death. Likewise, scanning electronic microscopy observations demonstrated obvious structural injury and morphological alteration of S. saprophyticus biofilm after PDI application. In conclusion, curcumin is an effective photosensitizer for the photodynamic control of S. saprophyticus biofilm.

scholarly journals Toyoncin—a novel leaderless bacteriocin produced by Bacillus toyonensis XIN-YC13 that specifically targets B. cereus and Listeria monocytogenes

2021 ◽  
Author(s):  
Juanjuan Wang ◽  
Haitao Xu ◽  
Shu Liu ◽  
Baolong Song ◽  
Hualin Liu ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Listeria Monocytogenes ◽  
Amino Acid ◽  
Cell Membrane ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Heat Stability ◽  
Important Food ◽  
Food Borne Pathogens ◽  
Food Borne

Bacteriocins have attracted increasing interest because of their potential as natural preservatives. Recent studies showed that the Bacillus cereus group is a prominent producer of bacteriocins. Using a laboratory-based screening strategy, we identified a strain in the B. cereus group, B. toyonensis XIN-YC13, with antimicrobial activity against B. cereus. A novel, 70-amino acid-long leaderless bacteriocin, toyoncin, was purified from the culture supernatant of strain XIN-YC13 and its molecular mass was found to be 7817.1012 Da. Toyoncin shares no similarity with any other known bacteriocins, and its N-terminal amino acid is formylmethionine rather than methionine. Toyoncin shows good pH and heat stability and exhibits specific antimicrobial activity against two important food-borne pathogens, B. cereus and Listeria monocytogenes. Additionally, toyoncin exerts bactericidal activity and induces cell membrane damage. Toyoncin can also inhibit the outgrowth of B. cereus spores. The preservation assays showed that toyoncin effectively suppressed or eradicated B. cereus and L. monocytogenes in pasteurized skim milk. These results suggest that toyoncin can be used as a new bio-preservative against B. cereus and L. monocytogenes in the food industry. Importance: We identified a novel leaderless bacteriocin, toyoncin, produced by B. toyonensis XIN-YC13. Toyoncin shows good pH and heat stability; has specific antimicrobial activity against, B. cereus and L. monocytogenes (two important food-borne pathogens), and destroys their cell membrane integrity. Toyoncin inhibited the outgrowth of B. cereus spores and effectively inhibited or eliminated B. cereus and L. monocytogenes in a milk model system. These results indicate the potential of toyoncin as a food preservative.

scholarly journals Enhanced recovery of Salmonella Typhimurium DT104 from exposure to stress at low temperature

Microbiology ◽  
2011 ◽  
Vol 157 (4) ◽  
pp. 1103-1114 ◽  
Author(s):  
Suzanne Humphrey ◽  
Leann F. Clark ◽  
Tom J. Humphrey ◽  
Mark A. Jepson
Keyword(s):  
Low Temperature ◽  
Enhanced Recovery ◽  
Phage Type ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Disease Outbreaks ◽  
Additional Stress ◽  
Food Borne ◽  
Serovar Typhimurium ◽  
Developed World

Salmonella enterica serovar Typhimurium (S. Typhimurium) remains an important cause of food-borne infection in the developed world. In order to establish infection within a host, Salmonella must survive and recover from a range of environmental stresses. S. Typhimurium strain SL1344 is among the most extensively studied pathogenic Salmonella strains, while S. Typhimurium phage type DT104 is an important type that has been associated with pandemic spread and a high number of food-borne disease outbreaks over the last two decades. In this study, we have compared the abilities of these two S. Typhimurium types to recover from stress exposures commonly encountered in food production, including 685 mM NaCl, pH 3.8, low temperature (6 °C) and combinations thereof. Following removal from prolonged (8 days) stress, DT104 cultures that had been exposed to low temperature, with or without additional stress, resumed exponential growth more rapidly than SL1344 cultures exposed to the same conditions. SL1344 showed higher levels of filamentation than DT104 in response to NaCl exposure at low temperature. Further, SL1344 incurred higher levels of membrane damage in response to elevated NaCl and pH 3.8 at both temperatures compared with DT104. However, both strains recovered normal cell division and membrane integrity within 6 h when all stresses were removed. Expression of the Salmonella pathogenicity island 1 gene prgH, the first gene in the prg/org operon, was monitored using a chromosomal reporter in which gfp+ expression was driven by the prgH promoter. Recovery of prgH expression was comparable for SL1344 and DT104 exposed to stress at 22 °C. However, DT104 cultures exposed to pH 3.8 or combined NaCl and low-pH stress at low temperature resumed prgH expression more rapidly than SL1344. Both strains recovered maximal levels of prgH expression after 6 h recovery from all stresses and, interestingly, maximal levels of prgH expression were significantly higher in SL1344, consistent with prgH expression in late-exponential, non-stressed SL1344 and DT104 cultures. Together, these data show that S. Typhimurium is capable of rapid recovery from environmental and food-related stresses, and give insight into the enhanced ability of DT104 compared with SL1344 to adapt to such stresses, which may contribute to the success of this globally disseminated pathogenic phage type.

IMPACT OF SORBITOL- INDUCED OSMOTIC STRESS ON SOME BIOCHEMICAL TRAITS OF POTATO IN VITRO

2020 ◽  
Vol 51 (4) ◽  
pp. 1038-1047
Author(s):  
Mawia & et al.
Keyword(s):  
Ascorbic Acid ◽  
Osmotic Stress ◽  
Cytoplasmic Membrane ◽  
Genotypic Variation ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Culture Collection ◽  
Nutritive Medium ◽  
Starting Point

This study had as principal objective identification of osmotic-tolerant potato genotypes by using "in vitro" tissue culture and sorbitol as a stimulating agent, to induce water stress, which was added to the  culture nutritive medium in different concentration (0,50, 110, 220, 330 and 440 mM).  The starting point was represented by plantlets culture collection, belonging to eleven potato genotypes: Barcelona, Nectar, Alison, Jelly, Malice, Nazca, Toronto, Farida, Fabulla, Colomba and Spunta. Plantlets were multiplied between two internodes to obtain microcuttings (in sterile condition), which were inoculated on medium. Sorbitol-induced osmotic stress caused a significant reduction in the ascorbic acid, while the concentration of proline, H2O2 and solutes leakage increased compared with the control. Increased the proline content prevented lipid peroxidation, which played a pivotal role in the maintenance of membrane integrity under osmotic stress conditions. The extent of the cytoplasmic membrane damage depends on osmotic stress severity and the genotypic variation in the maintenance of membranes stability was highly associated with the ability of producing more amounts of osmoprotectants (proline) and the non-enzymic antioxidant ascorbic acid in response to osmotic stress level. The results showed that the genotypes Jelly, Nectar, Allison, Toronto, and Colomba are classified as highly osmotic stress tolerant genotypes, while the genotypes Nazca and Farida are classified as osmotic stress susceptible ones.

scholarly journals Plasma membrane integrity: implications for health and disease

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Dustin A. Ammendolia ◽  
William M. Bement ◽  
John H. Brumell
Keyword(s):  
Plasma Membrane ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Whole Body ◽  
Plasma Membrane Integrity ◽  
Plasma Membrane Damage ◽  
Cellular Environment ◽  
Health And Disease ◽  
Repair Pathways ◽  
The Impact

AbstractPlasma membrane integrity is essential for cellular homeostasis. In vivo, cells experience plasma membrane damage from a multitude of stressors in the extra- and intra-cellular environment. To avoid lethal consequences, cells are equipped with repair pathways to restore membrane integrity. Here, we assess plasma membrane damage and repair from a whole-body perspective. We highlight the role of tissue-specific stressors in health and disease and examine membrane repair pathways across diverse cell types. Furthermore, we outline the impact of genetic and environmental factors on plasma membrane integrity and how these contribute to disease pathogenesis in different tissues.

scholarly journals Fluorescent Chitosan Nanogels Developed for Targeting Endothelial Cells of Axillary Lymph Nodes

2020 ◽  
Vol 4 (1) ◽  
pp. 12
Author(s):  
Miruna-Silvia Stan ◽  
Ionela Cristina Nica ◽  
Juliette Moreau ◽  
Maïté Callewaert ◽  
Cyril Cadiou ◽  
...  
Keyword(s):  
Membrane Damage ◽  
Membrane Integrity ◽  
Simian Virus 40 ◽  
Cancer Diagnostics ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Microvascular Endothelial Cell ◽  
Axillary Lymph Nodes ◽  
Cell Periphery ◽  
Axillary Lymph

Nanogels are a novel class of three-dimensional cross-linked polymers able to retain high amounts of water in their network structure, with large potential applications in nanomedicine. In our study, the polymer matrix selected was chitosan, as this polysaccharide biopolymer composed of N-acetylglucosamine and glucosamine residues exhibits great biocompatibility and low toxicity. The preparation was performed by ionic gelation in the presence of hyaluronic acid and sodium tripolyphosphate, with rhodamine or fluorescein isothiocyanate molecules grafted on a chitosan backbone. In order to validate the possible usage of these chitosan-fluorophores conjugates for fluorescence imaging purposes in cancer diagnostics and therapy, their biological effect was assessed on SVEC4-10 cells (a simian virus 40-transformed mouse microvascular endothelial cell line). Cell viability, membrane integrity and nanogels uptake were examined following exposure for 6 and 24 h at concentrations up to 120 µg/mL. A good biocompatibility was obtained after both time intervals of incubation with nanogels, with no increase in cell death or membrane damage being noticed as compared to control. By examination on confocal laser scanning microscopy, both types of fluorescent nanogels agglomerated on the surface of the cell membrane, their cellular internalization being observed only for few cells, preferentially at the cell periphery. In conclusion, based on the biocompatibility of the nanogels, these can further incorporate gadolinium for an improved magnetic resonance imaging effect in nanomedicine.

Hydraulic consequences of enzymatic breakdown of grapevine pit membranes

2021 ◽  
Author(s):  
Ana Clara Fanton ◽  
Craig Brodersen
Keyword(s):  
Hydraulic Conductivity ◽  
Vascular System ◽  
Membrane Surface ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Biological Response ◽  
Plant Host ◽  
Important Species ◽  
Membrane Area ◽  
Pit Membrane

Abstract Xylella fastidiosa (Xf) is the xylem-dwelling bacterial agent associated with Pierce’s Disease (PD), which leads to significant declines in productivity in agriculturally important species like grapevine (Vitis vinifera). Xf spreads through the xylem network by digesting the pit membranes between adjacent vessels, thereby potentially changing the hydraulic properties of the stem. However, the effects of Xf on water transport varies depending on the plant host and the infection stage, presenting diverse outcomes. Here, we investigated the effects of polygalacturonase, an enzyme known to be secreted by Xf when it produces biofilm on the pit membrane surface, on stem hydraulic conductivity and pit membrane integrity. Experiments were performed on six grapevine genotypes with varying levels of PD resistance, with the expectation that pit membrane resistance to degradation by polygalacturonase may play a role in PD-resistance. Our objective was to study a single component of this pathosystem in isolation to better understand the mechanisms behind reported changes in hydraulics, thereby excluding the biological response of the plant to the presence of Xf in the vascular system. Pit membrane damage only occurred in stems perfused with polygalacturonase. Although the damaged pit membrane area was small (2-9% of the total pit aperture area), membrane digestion led to significant changes in the median air-seeding thresholds, and most importantly, shifted frequency distribution. Finally, enzyme perfusion also resulted in a universal reduction in stem hydraulic conductivity, suggesting the development of tyloses may not be the only contributing factor to reduced hydraulic conductivity in infected grapevine.

scholarly journals Effects of freezing and activation on membrane quality and DNA damage in Xenopus tropicalis and Xenopus laevis spermatozoa

2017 ◽  
Vol 29 (8) ◽  
pp. 1556 ◽  
Author(s):  
S. Morrow ◽  
J. Gosálvez ◽  
C. López-Fernández ◽  
F. Arroyo ◽  
W. V. Holt ◽  
...  
Keyword(s):  
Xenopus Laevis ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Subsequent Development ◽  
Xenopus Tropicalis ◽  
Model Organisms ◽  
Sperm Chromatin ◽  
Dna Integrity ◽  
Sperm Cryopreservation ◽  
Sperm Plasma Membrane

There is growing concern over the effect of sperm cryopreservation on DNA integrity and the subsequent development of offspring generated from this cryopreserved material. In the present study, membrane integrity and DNA stability of Xenopus laevis and Xenopus tropicalis spermatozoa were evaluated in response to cryopreservation with or without activation, a process that happens upon exposure to water to spermatozoa of some aquatic species. A dye exclusion assay revealed that sperm plasma membrane integrity in both species decreased after freezing, more so for X. laevis than X. tropicalis spermatozoa. The sperm chromatin dispersion (SCD) test showed that for both X. tropicalis and X. laevis, activated frozen spermatozoa produced the highest levels of DNA fragmentation compared with all fresh samples and frozen non-activated samples (P < 0.05). Understanding the nature of DNA and membrane damage that occurs in cryopreserved spermatozoa from Xenopus species represents the first step in exploiting these powerful model organisms to understand the developmental consequences of fertilising with cryopreservation-damaged spermatozoa.

scholarly journals Proposed mechanism of antibacterial mode of action of Caesalpinia bonducella seed oil against food-borne pathogens

2016 ◽  
Vol 11 (1) ◽  
pp. 257
Author(s):  
Shruti Shukla ◽  
Rajib Majumder ◽  
Laxmi Ahirwal ◽  
Archana Mehta
Keyword(s):  
Electrical Conductivity ◽  
Mode Of Action ◽  
Seed Oil ◽  
Membrane Integrity ◽  
Extracellular Atp ◽  
Potassium Ions ◽  
Food Borne ◽  
Absorbing Materials ◽  
Caesalpinia Bonducella ◽  
Relative Electrical Conductivity

<p class="Abstract">The antibacterial mechanism of action of <em>Caesalpinia bonducella</em> seed oil on membrane permeability of <em>Listeria monocytogenes</em> NCIM 24563 (MIC: 2 mg/mL) and <em>Escherichia coli</em> ATCC 25922 (MIC: 4 mg/mL) was determined by measuring the extracellular ATP concentration, release of 260-nm absorbing materials, leakage of potassium ions and measurement of relative electrical conductivity of the bacterial cells treated at MIC concentration. Its mode of action on membrane integrity was confirmed by release of extracellular ATP (1.42 and 1.33 pg/mL), loss of 260-nm absorbing materials (4.36 and 4.19 optical density), leakage of potassium ions (950 and 1000 mmol/L) and increase in relative electrical conductivity (12.6 and 10.5%) against food-borne pathogenic bacteria <em>L. monocytogenes</em> and <em>E. coli</em>, respectively. These findings propose that <em>C. bonducella</em> oil compromised its mode of action on membrane integrity, suggesting its enormous food and pharmacological potential.</p><p> </p>

scholarly journals Biofilm Formation and Methylene Blue-mediated Photodynamic Inactivation of Vibrio Parahaemolyticus in the Sea Food Industry

2020 ◽  
Vol 10 (3) ◽  
Author(s):  
Xiaoting Zhang ◽  
Qian Wu ◽  
Shuze Tang ◽  
William W Riley ◽  
Zhenqiang Chen
Keyword(s):  
Methylene Blue ◽  
Crystal Violet ◽  
Biofilm Formation ◽  
Vibrio Parahaemolyticus ◽  
Food Industry ◽  
Membrane Integrity ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Photodynamic Inactivation ◽  
Log Reduction

This study was conducted to better understand the mechanism of Vibrio Parahaemolyticus biofilm formation and to assess the inactivation effects of methylene blue-mediated photodynamic inactivation (PDI) technology as a preventative measure. Optical microscopy, following crystal violet staining, was used to observe the kinetics of V. parahaemolyticus biofilm formation. The crystal violet-based assay was performed in microtiter plates, and it was employed to determine which factors were most influential in the formation of the biofilms. Colony counting and confocal laser scanning microscopy (CLSM) were used to test the inactivation effect of methylene blue-mediated photodynamic technology on the biofilms. V. parahaemolyticus has the ability to form biofilms, as evidenced by their immediate adherence to glass surfaces and rapid maturity, within 24 h. High (7%) or low (0.5%) salinity was not conducive to the formation of biofilms, and rotational speed greater than 130 rpm also inhibited the process. A 4.05 log reduction in the concentration of viable biofilm cells was obtained with 100 μg/mL methylene blue and 20 min irradiation (24.996 J/cm2), but planktonic cells were more susceptible to the methylene blue-mediated photodynamic reaction (5.46 log reduction). The results presented here show that the methylene blue-mediated PDI technology is an effective means to inactivate V. parahaemolyticus by disrupting its membrane integrity and to inhibit the pathogen’s formation of protective biofilms. This technology is a valid tool that can be used to enhance food safety in the sea food industry.

scholarly journals New techniques for real-time monitoring of reverse osmosis membrane integrity for virus removal

2018 ◽  
Vol 13 (4) ◽  
pp. 947-957 ◽  
Author(s):  
V. S. Frenkel ◽  
Y. Cohen
Keyword(s):  
Real Time ◽  
Reverse Osmosis ◽  
Health Hazard ◽  
Membrane Damage ◽  
Membrane Integrity ◽  
Enteric Viruses ◽  
Water Stream ◽  
Potential Health ◽  
Integrity Monitoring ◽  
Virus Removal

Abstract This paper presents methodology, concept and results of the WateReuse Foundation project WFR – 09 – 06b when developing a high pressure membrane, reverse osmosis (RO) and nanofiltration (NF) online membrane integrity testing (MIT) technique. The use of pressure-driven membrane processes, particularly RO, has grown significantly over the past few decades in water treatment and reuse applications to safeguard water supplies against harmful pathogens and impurities. In principle, RO membranes should provide a complete physical barrier to the passage of nanosize pathogens (e.g., enteric viruses). However, in the presence of imperfections and/or membrane damage, membrane breaches as small as 20 to 30 nm can allow enteric viruses to pass through the membrane and contaminate the product water stream, thereby posing a potential health hazard that is of particular concern for potable water production. This project was focused on evaluating a pulsed-marker membrane integrity monitoring (PM-MIMo) approach for RO processes on the basis of the use of a fluorescent marker. The monitoring approach employs pulsed dosing (via a precision metering pump) of a marker into the RO feed stream coupled with online marker concentration monitoring in the RO permeate by an inline spectrofluorometer. Membrane integrity is then inferred on the basis of real-time analysis of the marker permeate time − profile concentration in response. The basic concept of the PM-MIMo approach for detecting membrane breaches was successfully demonstrated, by comparing intact and damaged membranes, in a series of experiments using a diagnostic plate-and-frame RO system and spiral-wound RO pilot system. Results of the developed technique are presented in the project report to allow the industry to consider adopting this technique for RO/NF online integrity monitoring.

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