scholarly journals Resistance of L. monocytogenes and S. Typhimurium towards Cold Atmospheric Plasma as Function of Biofilm Age

2018 ◽  
Vol 8 (12) ◽  
pp. 2702 ◽  
Author(s):  
Marlies Govaert ◽  
Cindy Smet ◽  
Maria Baka ◽  
Branimir Ećimović ◽  
James L. Walsh ◽  
...  

The biofilm mode of growth protects bacterial cells against currently applied disinfection methods for abiotic (food) contact surfaces. Therefore, innovative methods, such as Cold Atmospheric Plasma (CAP), should be investigated for biofilm inactivation. However, more knowledge is required concerning the influence of the biofilm age on the inactivation efficacy in order to comment on a possible application of CAP in the (food) processing industry. L. monocytogenes and S. Typhimurium biofilms with five different ages (i.e., 1, 2, 3, 7, and 10 days) were developed. For the untreated biofilms, the total biofilm mass and the cell density were determined. To investigate the biofilm resistance towards CAP treatment, biofilms with different ages were treated for 10 min and the remaining cell density was determined. Finally, for the one-day old reference biofilms and the most resistant biofilm age, complete inactivation curves were developed to examine the influence of the biofilm age on the inactivation kinetics. For L. monocytogenes, an increased biofilm age resulted in (i) an increased biomass, (ii) a decreased cell density prior to CAP treatment, and (iii) an increased resistance towards CAP treatment. For S. Typhimurium, similar results were obtained, except for the biomass, which was here independent of the biofilm age.

Foods ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 157 ◽  
Author(s):  
Marlies Govaert ◽  
Cindy Smet ◽  
Annika Graeffe ◽  
James L. Walsh ◽  
Jan F. M. Van Impe

Previous (biofilm) inactivation studies using Cold Atmospheric Plasma (CAP) focused on helium (with or without the addition of oxygen) as feeding gas since this proved to result in a stable and uniform plasma. In industry, the use of helium gas is expensive and unsafe for employees. Ambient air is a possible substitute, provided that similar inactivation efficacies can be obtained. In this research, 1 and 7 day-old (single/dual-species) model biofilms containing L. monocytogenes and/or S. typhimurium cells were treated with an air-based Surface Barrier Discharge (SBD) plasma set-up for treatment times between 0 and 30 min. Afterwards, cell densities were quantified via viable plate counts, and predictive models were applied to determine the inactivation kinetics and the efficacy. Finally, the results were compared to previously obtained results using a helium-based SBD and DBD (Dielectric Barrier Discharge) system. This study has demonstrated that the efficacy of the air-based CAP treatment depended on the biofilm and population type, with log-reductions ranging between 1.5 and 2.5 log10(CFU/cm2). The inactivation efficacy was not significantly influenced by the working gas, although the values were generally higher for the air-based system. Finally, this study has demonstrated that the electrode configuration was more important than the working gas composition, with the DBD electrode being the most efficient.


Biomedicines ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1259
Author(s):  
Dayun Yan ◽  
Alisa Malyavko ◽  
Qihui Wang ◽  
Kostya (Ken) Ostrikov ◽  
Jonathan H. Sherman ◽  
...  

Cold atmospheric plasma (CAP) is a near-room-temperature, partially ionized gas composed of reactive neutral and charged species. CAP also generates physical factors, including ultraviolet (UV) radiation and thermal and electromagnetic (EM) effects. Studies over the past decade demonstrated that CAP could effectively induce death in a wide range of cell types, from mammalian to bacterial cells. Viruses can also be inactivated by a CAP treatment. The CAP-triggered cell-death types mainly include apoptosis, necrosis, and autophagy-associated cell death. Cell death and virus inactivation triggered by CAP are the foundation of the emerging medical applications of CAP, including cancer therapy, sterilization, and wound healing. Here, we systematically analyze the entire picture of multi-modal biological destruction by CAP treatment and their underlying mechanisms based on the latest discoveries particularly the physical effects on cancer cells.


2019 ◽  
Vol 16 (1) ◽  
pp. 0151 ◽  
Author(s):  
Atta Et al.

baumannii is an aerobic gram negative coccobacilli, it is considered multidrug resistance pathogen (MDR) and causes several infections that are difficult to treat. This study is aims to employ physical methods in sterilization and inactivation of A. baumannii, as an alternative way to reduce the using of drugs and antibiotics.             Cold Atmospheric Plasma was generated by one electrode at 20KV, 4 power supply and distance between electrode and sample was fixed on 1mm. A. baumannii (ATCC 19704 and HHR1) were exposed to  Dielectric Barrier Discharge type of Cold Atmospheric Plasma (DBD-CAP) for several periods of time (15, 30, 45, and 60 sec.) . After sterilization test, several methods were done to analyze the effect of DBD-CAP on bacterial morphology, proteins and DNA. Change in morphology was assessed by cover slid method. Damaged DNA was investigated by PCR technique, and DNA sequencing. The impact of DBD-CAP on the entity of proteins was detected by SDS-PAGE. The observed inactivation of bacterial colony on agar plates has been quantified by measuring the inactivation diameter. The important conclusion that HHR1 more resistance to DBD-CAP than ATCC 17904 because it is more virulence than standard strain; thus, the growth of both strains is largely affected by plasma and this influence is increased by increasing the time of exposure, also the plasma affects the DNA especially on standard strain as it is explained in sequencing result, so it causes more deletion in DNA sequence. In addition, plasma also has been showed to damage proteins and morphology thus, the bacterial cells transform from cocco-bacillus to bacillus.


2019 ◽  
Vol 16 (1(Suppl.)) ◽  
pp. 0151 ◽  
Author(s):  
Atta Et al.

baumannii is an aerobic gram negative coccobacilli, it is considered multidrug resistance pathogen (MDR) and causes several infections that are difficult to treat. This study is aims to employ physical methods in sterilization and inactivation of A. baumannii, as an alternative way to reduce the using of drugs and antibiotics.             Cold Atmospheric Plasma was generated by one electrode at 20KV, 4 power supply and distance between electrode and sample was fixed on 1mm. A. baumannii (ATCC 19704 and HHR1) were exposed to  Dielectric Barrier Discharge type of Cold Atmospheric Plasma (DBD-CAP) for several periods of time (15, 30, 45, and 60 sec.) . After sterilization test, several methods were done to analyze the effect of DBD-CAP on bacterial morphology, proteins and DNA. Change in morphology was assessed by cover slid method. Damaged DNA was investigated by PCR technique, and DNA sequencing. The impact of DBD-CAP on the entity of proteins was detected by SDS-PAGE. The observed inactivation of bacterial colony on agar plates has been quantified by measuring the inactivation diameter. The important conclusion that HHR1 more resistance to DBD-CAP than ATCC 17904 because it is more virulence than standard strain; thus, the growth of both strains is largely affected by plasma and this influence is increased by increasing the time of exposure, also the plasma affects the DNA especially on standard strain as it is explained in sequencing result, so it causes more deletion in DNA sequence. In addition, plasma also has been showed to damage proteins and morphology thus, the bacterial cells transform from cocco-bacillus to bacillus.


2011 ◽  
Vol 13 (2) ◽  
pp. 201-171
Author(s):  
Nāṣir Al-Dīn Abū Khaḍīr

The ʿUthmānic way of writing (al-rasm al-ʿUthmānī) is a science that specialises in the writing of Qur'anic words in accordance with a specific ‘pattern’. It follows the writing style of the Companions at the time of the third caliph, ʿUthmān b. ʿAffān, and was attributed to ʿUthmān on the basis that he was the one who ordered the collection and copying of the Qur'an into the actual muṣḥaf. This article aims to expound on the two fundamental functions of al-rasm al-ʿUthmānī: that of paying regard to the ‘correct’ pronunciation of the words in the muṣḥaf, and the pursuit of the preclusion of ambiguity which may arise in the mind of the reader and his auditor. There is a further practical aim for this study: to show the connection between modern orthography and the ʿUthmānic rasm in order that we, nowadays, are thereby able to overcome the problems faced by calligraphers and writers of the past in their different ages and cultures.


2018 ◽  
Vol 18 (6) ◽  
pp. 784-804 ◽  
Author(s):  
Georg Bauer

Background: Application of cold atmospheric plasma to medium generates “plasma-activated medium” that induces apoptosis selectively in tumor cells and that has an antitumor effect in vivo. The underlying mechanisms are not well understood. Objective: Elucidation of potential chemical interactions within plasma-activated medium and of reactions of medium components with specific target structures of tumor cells should allow to define the active principle in plasma activated medium. Methods: Established knowledge of intercellular apoptosis-inducing reactive oxygen/nitrogen species-dependent signaling and its control by membrane-associated catalase and SOD was reviewed. Model experiments using extracellular singlet oxygen were analyzed with respect to catalase inactivation and their relevance for the antitumor action of cold atmospheric plasma. Potential interactions of this tumor cell-specific control system with components of plasma-activated medium or its reaction products were discussed within the scope of the reviewed signaling principles. Results: None of the long-lived species found in plasma-activated medium, such as nitrite and H2O2, nor OCl- or .NO seemed to have the potential to interfere with catalase-dependent control of apoptosis-inducing signaling of tumor cells when acting alone. However, the combination of H2O2 and nitrite might generate peroxynitrite. The protonation of peroxnitrite to peroxynitrous acid allows for the generation of hydroxyl radicals that react with H2O2, leading to the formation of hydroperoxide radicals. These allow for singlet oxygen generation and inactivation of membrane-associated catalase through an autoamplificatory mechanism, followed by intercellular apoptosis-inducing signaling. Conclusion: Nitrite and H2O2 in plasma-activated medium establish singlet oxygen-dependent interference selectively with the control system of tumor cells.


2018 ◽  
Vol 18 (6) ◽  
pp. 769-775 ◽  
Author(s):  
Dayun Yan ◽  
Jonathan H. Sherman ◽  
Michael Keidar

Background: Over the past five years, the cold atmospheric plasma-activated solutions (PAS) have shown their promissing application in cancer treatment. Similar as the common direct cold plasma treatment, PAS shows a selective anti-cancer capacity in vitro and in vivo. However, different from the direct cold atmospheric plasma (CAP) treatment, PAS can be stored for a long time and can be used without dependence on a CAP device. The research on PAS is gradually becoming a hot topic in plasma medicine. Objectives: In this review, we gave a concise but comprehensive summary on key topics about PAS including the development, current status, as well as the main conclusions about the anti-cancer mechanism achieved in past years. The approaches to make strong and stable PAS are also summarized.


Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 249
Author(s):  
Zhitong Chen ◽  
Richard Obenchain ◽  
Richard E. Wirz

Conventional plasma jets for biomedical applications tend to have several drawbacks, such as high voltages, high gas delivery, large plasma probe volume, and the formation of discharge within the organ. Therefore, it is challenging to employ these jets inside a living organism’s body. Thus, we developed a single-electrode tiny plasma jet and evaluated its use for clinical biomedical applications. We investigated the effect of voltage input and flow rate on the jet length and studied the physical parameters of the plasma jet, including discharge voltage, average gas and subject temperature, and optical emissions via spectroscopy (OES). The interactions between the tiny plasma jet and five subjects (de-ionized (DI) water, metal, cardboard, pork belly, and pork muscle) were studied at distances of 10 mm and 15 mm from the jet nozzle. The results showed that the tiny plasma jet caused no damage or burning of tissues, and the ROS/RNS (reactive oxygen/nitrogen species) intensity increased when the distance was lowered from 15 mm to 10 mm. These initial observations establish the tiny plasma jet device as a potentially useful tool in clinical biomedical applications.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Olivia Jones ◽  
Xiaoqian Cheng ◽  
Saravana R. K. Murthy ◽  
Lawan Ly ◽  
Taisen Zhuang ◽  
...  

AbstractCholangiocarcinoma (CCA) is a rare biliary tract cancer with a low five-year survival rate and high recurrence rate after surgical resection. Currently treatment approaches include systemic chemotherapeutics such as FOLFIRINOX, a chemotherapy regimen is a possible treatment for severe CCA cases. A limitation of this chemotherapy regimen is its toxicity to patients and adverse events. There exists a need for therapies to alleviate the toxicity of a FOLFIRINOX regimen while enhancing or not altering its anticancer properties. Cold atmospheric plasma (CAP) is a technology with a promising future as a selective cancer treatment. It is critical to know the potential interactions between CAP and adjuvant chemotherapeutics. In this study the aim is to characterize the efficacy of FOLFIRINOX and CAP in combination to understand potential synergetic effect on CCA cells. FOLFIRINOX treatment alone at the highest dose tested (53.8 µM fluorouracil, 13.7 µM Leucovorin, 5.1 µM Irinotecan, and 3.7 µM Oxaliplatin) reduced CCA cell viability to below 20% while CAP treatment alone for 7 min reduced viability to 3% (p < 0.05). An analysis of cell viability, proliferation, and cell cycle demonstrated that CAP in combination with FOLFIRINOX is more effective than either treatment alone at a lower FOLFIRINOX dose of 6.7 µM fluorouracil, 1.7 µM leucovorin, 0.6 µM irinotecan, and 0.5 µM oxaliplatin and a shorter CAP treatment of 1, 3, or 5 min. In conclusion, CAP has the potential to reduce the toxicity burden of FOLFIRINOX and warrants further investigation as an adjuvant therapy.


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