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Li Z, He Q, Xu F, Yin X, Guan Z, Song J, He Z, Yang X, Situ C. Exploring the Antibacterial Potential and Underlying Mechanisms of Prunella vulgaris L. on Methicillin-Resistant Staphylococcus aureus. Foods 2024; 13:660. [PMID: 38472772 DOI: 10.3390/foods13050660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Revised: 02/08/2024] [Accepted: 02/16/2024] [Indexed: 03/14/2024] Open
Abstract
Prunella vulgaris L. (PV) is a widely distributed plant species, known for its versatile applications in both traditional and contemporary medicine, as well as in functional food development. Despite its broad-spectrum antimicrobial utility, the specific mechanism of antibacterial action remains elusive. To fill this knowledge gap, the present study investigated the antibacterial properties of PV extracts against methicillin-resistant Staphylococcus aureus (MRSA) and assessed their mechanistic impact on bacterial cells and cellular functions. The aqueous extract of PV demonstrated greater anti-MRSA activity compared to the ethanolic and methanolic extracts. UPLC-ESI-MS/MS tentatively identified 28 phytochemical components in the aqueous extract of PV. Exposure to an aqueous extract at ½ MIC and MIC for 5 h resulted in a significant release of intracellular nucleic acid (up to 6-fold) and protein (up to 10-fold) into the extracellular environment. Additionally, this treatment caused a notable decline in the activity of several crucial enzymes, including a 41.51% reduction in alkaline phosphatase (AKP), a 45.71% decrease in adenosine triphosphatase (ATPase), and a 48.99% drop in superoxide dismutase (SOD). Furthermore, there was a decrease of 24.17% at ½ MIC and 27.17% at MIC in tricarboxylic acid (TCA) cycle activity and energy transfer. Collectively, these findings indicate that the anti-MRSA properties of PV may stem from its ability to disrupt membrane and cell wall integrity, interfere with enzymatic activity, and impede bacterial cell metabolism and the transmission of information and energy that is essential for bacterial growth, ultimately resulting in bacterial apoptosis. The diverse range of characteristics exhibited by PV positions it as a promising antimicrobial agent with broad applications for enhancing health and improving food safety and quality.
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Affiliation(s)
- Ziyin Li
- Food Safety and Health Research Center, NMPA Key Laboratory for Safety Evaluation of Cosmetics, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 500515, China
| | - Qiqi He
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast BT9 5DL, UK
| | - Feifei Xu
- Food Safety and Health Research Center, NMPA Key Laboratory for Safety Evaluation of Cosmetics, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 500515, China
| | - Xinxin Yin
- Food Safety and Health Research Center, NMPA Key Laboratory for Safety Evaluation of Cosmetics, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 500515, China
| | - Zhuofan Guan
- Food Safety and Health Research Center, NMPA Key Laboratory for Safety Evaluation of Cosmetics, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 500515, China
| | - Jia Song
- Food Safety and Health Research Center, NMPA Key Laboratory for Safety Evaluation of Cosmetics, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 500515, China
| | - Zhini He
- Food Safety and Health Research Center, NMPA Key Laboratory for Safety Evaluation of Cosmetics, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 500515, China
| | - Xingfen Yang
- Food Safety and Health Research Center, NMPA Key Laboratory for Safety Evaluation of Cosmetics, Guangdong Provincial Key Laboratory of Tropical Disease Research, School of Public Health, Southern Medical University, Guangzhou 500515, China
| | - Chen Situ
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast BT9 5DL, UK
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2
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Song E, Lee K, Kim J. Tetrazolium-Based Visually Indicating Bacteria Sensor for Colorimetric Detection of Point of Contamination. ACS APPLIED MATERIALS & INTERFACES 2022; 14:38153-38161. [PMID: 35946791 PMCID: PMC9415389 DOI: 10.1021/acsami.2c08613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2022] [Accepted: 08/02/2022] [Indexed: 06/15/2023]
Abstract
Protective equipment for detecting bacterial contamination has been in high demand with increasing interest in public health and hygiene. Herein, a fiber-based visually indicating bacteria sensor (VIBS) embedded with iodonitrotetrazolium chloride is developed for the general purpose of detecting live bacteria, and its chromogenic effectiveness is investigated for Gram-negative Escherichia coli and Gram-positive Micrococcus luteus. The developed color intensity is measured by the light absorption coefficient to the scattering coefficient (K/S) based on the Kubelka-Munk equation, and the colorimetric sensitivities of different membranes are examined by calculating the limit of detection (LOD) and the limit of quantification (LOQ). The results demonstrate that the interactions between VIBS and bacteria depend on the wetting properties of membranes. A hydrophobic membrane shows excessive interactions at high concentrations of Gram-negative E. coli bacteria, whose cell membrane is lipophilic. The membrane blended with hydrophobic and hydrophilic polymers displays linear colorimetric responses for both Gram-negative and Gram-positive bacteria strains, demonstrating a reliable sensing capability in the range of the tested bacteria concentration. This study is significant in that explorative experimentations are performed to conceive a proof of concept of a fiber-based bacteria sensor, which is readily applicable in various fields where bacteria pose a threat.
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Affiliation(s)
- Eugene Song
- Department
of Textiles, Merchandising and Fashion Design, Seoul National University, Seoul 08826, Korea
| | - Kyeongeun Lee
- Department
of Textiles, Merchandising and Fashion Design, Seoul National University, Seoul 08826, Korea
- Reliability
Assessment Center, FITI Testing & Research
Institute, Seoul 07791, Korea
| | - Jooyoun Kim
- Department
of Textiles, Merchandising and Fashion Design, Seoul National University, Seoul 08826, Korea
- Research
Institute of Human Ecology, Seoul National
University, Seoul 08826, Korea
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3
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Guo C, Ke Y, Chen B, Zhang S, Liu H. Making comparable measurements of bacterial respiration and production in the subtropical coastal waters. MARINE LIFE SCIENCE & TECHNOLOGY 2022; 4:414-427. [PMID: 37073168 PMCID: PMC10077172 DOI: 10.1007/s42995-022-00133-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 05/02/2022] [Indexed: 05/03/2023]
Abstract
Accurate estimates of bacterial carbon metabolic rates are indispensable for understanding the regulation of carbon fluxes in aquatic environments. Here, changes in bacterial growth, production, and cell volume in both pre-filtered and unfiltered seawater during 24 h incubation were monitored. The methodological artifacts during Winkler bacterial respiration (BR) measurements in subtropical Hong Kong coastal waters were assessed. Bacterial abundance increased by 3- and 1.8-fold in the pre-filtered and unfiltered seawater after incubation, respectively. Bacterial production (BP) and cell volume also showed significant enhancement. Compared with the BR measurements obtained by the Winkler method, the instantaneous free-living BR measurements, after correction, decreased by ~ 70%. The time-integrated free-living BR and BP during 24 h incubation in the pre-filtered sample provided an improved estimate of bacterial growth efficiency, which increased by ~ 52% compared to the common estimations using the noncomparable measurements of integrated free-living BR and instantaneous total BP. The overestimation of BR also exaggerated the contribution of bacteria to community respiration, affecting the understanding on the metabolic state of the marine ecosystems. Furthermore, the BR estimates by the Winkler method may be more biased in environments with a higher bacterial growth rate and tightly coupled grazing mortality, as well as in those with higher nutrient concentrations. These results reveal obvious problems associated with the BR methodology and raise a warning for caution when comparing BP and BR, as well as when making estimations of carbon flow through the complex microbial networks in aquatic ecosystems. Supplementary Information The online version contains supplementary material available at 10.1007/s42995-022-00133-2.
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Affiliation(s)
- Cui Guo
- College of Marine Life Sciences, Institute of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System, Ocean University of China, Qingdao, 266003 China
| | - Ying Ke
- Division of Life Science, The Hong Kong University of Science and Technology, Hong Kong, SAR China
| | - Bingzhang Chen
- Department of Mathematics and Statistics, University of Strathclyde, Glasgow, G1 1XH UK
- Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Hong Kong University of Science and Technology, Hong Kong, SAR China
| | - Shuwen Zhang
- College of Life Science, South China Normal University, Guangzhou, 510631 China
| | - Hongbin Liu
- Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Hong Kong University of Science and Technology, Hong Kong, SAR China
- Department of Ocean Science, Hong Kong University of Science and Technology, Hong Kong, SAR China
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4
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Deng H, Cao J, Wang D, Zhu J, Ma L. Effects of high hydrostatic pressure on inactivation, morphological damage, and enzyme activity of
Escherichia coli
O157:H7. J Food Saf 2022. [DOI: 10.1111/jfs.12998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Haotian Deng
- College of Food Science Shenyang Agricultural University Shenyang Liaoning Province China
| | - Jijuan Cao
- Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education Dalian Minzu University Dalian Liaoning Province China
| | - Dianfu Wang
- Eastern Liaoning University Dandong Liaoning Province China
| | - Jinyan Zhu
- College of Food Science Shenyang Agricultural University Shenyang Liaoning Province China
- Food Inspection Monitoring Center of Zhuanghe Dalian Liaoning Province China
| | - Lidan Ma
- Dandong Customs of the People's Republic of China Dandong Liaoning Province China
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5
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Wei XF, Zhu QS, Guo JD, Shang JK. Obtaining ultra-high throwing power in Cu electroplating of flexible printed circuit by fast consumption of a suppressor. J Solid State Electrochem 2021. [DOI: 10.1007/s10008-021-05055-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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6
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Philus CD, Mahanty B. Dynamic modelling of tetrazolium-based microbial toxicity assay-a parametric proxy of traditional dose-response relationship. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2021; 28:45390-45401. [PMID: 33866499 DOI: 10.1007/s11356-021-13870-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 04/06/2021] [Indexed: 06/12/2023]
Abstract
Microbial toxicity of test substances in tetrazolium assay is often quantified while referring to their IC50 values. However, the implication of such an estimate is very limited and can differ across studies depending on prevailing test conditions. In this work, a factorial design-based end-point microbial toxicity assay was performed, which suggests a significant interaction (P= 0.041) between inoculum and tetrazolium dose on formazan production. Subsequently, a dynamic model framework was utilized to capture the nonlinearities in biomass, substrate, formazan profiles and to project the toxicant inhibition parameter as a robust alternative to IC50 value. Microbial growth, glucose uptake and formazan production in the presence or absence of toxicant (Cu2+) from designed batch experiments were used for sequential estimation of model parameters, and their confidence intervals. A logistic growth model with multiplicative inhibition terms for formazan content and toxicant concentration fits the experimental data reasonably well (R2>0.96). Dynamic relative sensitivity analysis revealed that both microbial growth and formazan production profiles were sensitive to toxicant inhibition parameter. The modelling framework not only provides a better insight into the underlying toxic effect but also offers a stable toxicity index for the test substances that can be extended to design a versatile, robust in vitro assay system.
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Affiliation(s)
- Chris Daniel Philus
- Department of Biotechnology, Karunya Institute of Technology and Sciences, Coimbatore, Tamil Nadu, 641114, India
| | - Biswanath Mahanty
- Department of Biotechnology, Karunya Institute of Technology and Sciences, Coimbatore, Tamil Nadu, 641114, India.
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7
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Mori F, Umezawa Y, Kondo R, Nishihara GN, Wada M. Potential oxygen consumption and community composition of sediment bacteria in a seasonally hypoxic enclosed bay. PeerJ 2021; 9:e11836. [PMID: 34434647 PMCID: PMC8362671 DOI: 10.7717/peerj.11836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 07/01/2021] [Indexed: 01/04/2023] Open
Abstract
The dynamics of potential oxygen consumption at the sediment surface in a seasonally hypoxic bay were monitored monthly by applying a tetrazolium dye (2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride [INT]) reduction assay to intact sediment core samples for two consecutive years (2012–2013). Based on the empirically determined correlation between INT reduction (INT-formazan formation) and actual oxygen consumption of sediment samples, we inferred the relative contribution of biological and non-biological (chemical) processes to the potential whole oxygen consumption in the collected sediment samples. It was demonstrated that both potentials consistently increased and reached a maximum during summer hypoxia in each year. For samples collected in 2012, amplicon sequence variants (ASVs) of the bacterial 16S rRNA genes derived from the sediment surface revealed a sharp increase in the relative abundance of sulfate reducing bacteria toward hypoxia. In addition, a notable shift in other bacterial compositions was observed before and after the INT assay incubation. It was Arcobacter (Arcobacteraceae, Campylobacteria), a putative sulfur-oxidizing bacterial genus, that increased markedly during the assay period in the summer samples. These findings have implications not only for members of Delta- and Gammaproteobacteria that are consistently responsible for the consumption of dissolved oxygen (DO) year-round in the sediment, but also for those that might grow rapidly in response to episodic DO supply on the sediment surface during midst of seasonal hypoxia.
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Affiliation(s)
- Fumiaki Mori
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Nagasaki, Japan.,Institute for East China Sea Research, Organization for Marine Science and Technology, Nagasaki University, Nagasaki, Nagasaki, Japan.,Kochi Institute for Core Sample Research, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Kochi, Japan
| | - Yu Umezawa
- Department of Environmental Science on Biosphere, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Ryuji Kondo
- Department of Marine Science and Technology, Fukui Prefectural University, Fukui, Japan
| | - Gregory N Nishihara
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Nagasaki, Japan.,Institute for East China Sea Research, Organization for Marine Science and Technology, Nagasaki University, Nagasaki, Nagasaki, Japan
| | - Minoru Wada
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, Nagasaki, Japan
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8
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Braissant O, Astasov-Frauenhoffer M, Waltimo T, Bonkat G. A Review of Methods to Determine Viability, Vitality, and Metabolic Rates in Microbiology. Front Microbiol 2020; 11:547458. [PMID: 33281753 PMCID: PMC7705206 DOI: 10.3389/fmicb.2020.547458] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 10/08/2020] [Indexed: 12/21/2022] Open
Abstract
Viability and metabolic assays are commonly used as proxies to assess the overall metabolism of microorganisms. The variety of these assays combined with little information provided by some assay kits or online protocols often leads to mistakes or poor interpretation of the results. In addition, the use of some of these assays is restricted to simple systems (mostly pure cultures), and care must be taken in their application to environmental samples. In this review, the necessary data are compiled to understand the reactions or measurements performed in many of the assays commonly used in various aspects of microbiology. Also, their relationships to each other, as metabolism links many of these assays, resulting in correlations between measured values and parameters, are discussed. Finally, the limitations of these assays are discussed.
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Affiliation(s)
- Olivier Braissant
- Department of Biomedical Engineering, Faculty of Medicine, University of Basel, Allschwil, Switzerland
| | | | - Tuomas Waltimo
- Department Research, University Center for Dental Medicine, University of Basel, Basel, Switzerland
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9
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Baños I, Montero MF, Benavides M, Arístegui J. INT Toxicity over Natural Bacterial Assemblages from Surface Oligotrophic Waters: Implications for the Assessment of Respiratory Activity. MICROBIAL ECOLOGY 2020; 80:237-242. [PMID: 31915852 DOI: 10.1007/s00248-019-01479-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 12/22/2019] [Indexed: 06/10/2023]
Abstract
Plankton community respiration (R) is a major component of the carbon flux in aquatic ecosystems. However, current methods to measure actual respiration from oxygen consumption at relevant spatial scales are not sensitive enough in oligotrophic environments where respiration rates are very low. To overcome this drawback, more sensitive indirect enzymatic approaches are commonly used as R proxies. The in vivo electron transport system (ETSvivo) assay, which measures the reduction of (2-(4-iodophenyl)-3-(4-nitrophenyl)-5-phenyl tetrazolium chloride salt, INT) to INT-formazan in the presence of natural substrate levels, was recently proposed as an indirect reliable estimation of R for natural plankton communities. However, under in vivo conditions, formazan salts could be toxic to the cells. Here, we test the toxicity of 0.2 mM of final INT concentration, widely used for ETSvivo assays, on natural bacterial assemblages collected in coastal and oceanic waters off Gran Canaria (Canary Islands, subtropical North Atlantic), in eight independent experiments. After 0.5 h of incubation, a significant but variable decline in cell viability (14-49%) was observed in all samples inoculated with INT. Moreover, INT also inhibited leucine uptake in less than 90 min of incubation. In the light of these results, we argue that enzymatic respiratory rates obtained with the ETSvivo method need to be interpreted with caution to derive R in oceanic regions where bacteria largely contribute to community respiration. Moreover, the variable toxicity on bacterial assemblages observed in our experiments questions the use of a single R/ETSvivo relationship as a universal proxy for regional studies.
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Affiliation(s)
- Isabel Baños
- Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - María F Montero
- Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain
| | - Mar Benavides
- Aix-Marseille Université, Université de Toulon, CNRS, IRD, Mediterranean Institute of Oceanography (MIO), UM 110, 13288, Marseille, France
| | - Javier Arístegui
- Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria, Las Palmas de Gran Canaria, Spain.
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10
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García-Martín EE, Seguro I, Robinson C. INT reduction is a valid proxy for eukaryotic plankton respiration despite the inherent toxicity of INT and differences in cell wall structure. PLoS One 2019; 14:e0225954. [PMID: 31821369 PMCID: PMC6903736 DOI: 10.1371/journal.pone.0225954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 11/16/2019] [Indexed: 11/23/2022] Open
Abstract
The reduction of 2-para (iodophenyl)-3(nitrophenyl)-5(phenyl) tetrazolium chloride (INT) is increasingly being used as an indirect method to measure plankton respiration. Its greater sensitivity and shorter incubation time compared to the standard method of measuring the decrease in dissolved oxygen concentration, allows the determination of total and size-fractionated plankton respiration with higher precision and temporal resolution. However, there are still concerns as to the method’s applicability due to the toxicity of INT and the potential differential effect of plankton cell wall composition on the diffusion of INT into the cell, and therefore on the rate of INT reduction. Working with cultures of 5 marine plankton (Thalassiosira pseudonana CCMP1080/5, Emiliania huxleyi RCC1217, Pleurochrysis carterae PLY-406, Scrippsiella sp. RCC1720 and Oxyrrhis marina CCMP1133/5) which have different cell wall compositions (silica frustule, presence/absence of calcite and cellulose plates), we demonstrate that INT does not have a toxic effect on oxygen consumption at short incubation times. There was no difference in the oxygen consumption of a culture to which INT had been added and that of a replicate culture without INT, for periods of time ranging from 1 to 7 hours. For four of the cultures (T. pseudonana CCMP1080/5, P. carterae PLY-406, E. huxleyi RCC1217, and O. marina CCMP1133/5) the log of the rates of dissolved oxygen consumption were linearly related to the log of the rates of INT reduction, and there was no significant difference between the regression lines for each culture (ANCOVA test, F = 1.696, df = 3, p = 0.18). Thus, INT reduction is not affected by the structure of the plankton cell wall and a single INT reduction to oxygen consumption conversion equation is appropriate for this range of eukaryotic plankton. These results further support the use of the INT technique as a valid proxy for marine plankton respiration.
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Affiliation(s)
- E Elena García-Martín
- Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, Norfolk, United Kingdom
| | - Isabel Seguro
- Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, Norfolk, United Kingdom
| | - Carol Robinson
- Centre for Ocean and Atmospheric Sciences, School of Environmental Sciences, University of East Anglia, Norwich, Norfolk, United Kingdom
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11
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ε-Polylysine Inhibits Shewanella putrefaciens with Membrane Disruption and Cell Damage. Molecules 2019; 24:molecules24203727. [PMID: 31623152 PMCID: PMC6832906 DOI: 10.3390/molecules24203727] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Revised: 10/10/2019] [Accepted: 10/14/2019] [Indexed: 12/22/2022] Open
Abstract
ε-Polylysine (ε-PL) was studied for the growth inhibition of Shewanella putrefaciens (S. putrefaciens). The minimal inhibitory concentration (MIC) of ε-PL against S. putrefaciens was measured by the broth dilution method, while the membrane permeability and metabolism of S. putrefaciens were assessed after ε-PL treatment. Additionally, growth curves, the content of alkaline phosphatase (AKP), the electrical conductivity (EC), the UV absorbance and scanning electron microscope (SEM) data were used to study cellular morphology. The impact of ε-PL on cell metabolism was also investigated by different methods, such as enzyme activity (peroxidase [POD], catalase [CAT], succinodehydrogenase [SDH] and malic dehydrogenase [MDH]) and cell metabolic activity. The results showed that the MIC of ε-PL against S. putrefaciens was 1.0 mg/mL. When S. putrefaciens was treated with ε-PL, the growth of the bacteria was inhibited and the AKP content, electrical conductivity and UV absorbance were increased, which demonstrated that ε-PL could damage the cell structure. The enzyme activities of POD, CAT, SDH, and MDH in the bacterial solution with ε-PL were decreased compared to those in the ordinary bacterial solution. As the concentration of ε-PL was increased, the enzyme activity decreased further. The respiratory activity of S. putrefaciens was also inhibited by ε-PL. The results suggest that ε-PL acts on the cell membrane of S. putrefaciens, thereby increasing membrane permeability and inhibiting enzyme activity in relation to respiratory metabolism and cell metabolism. This leads to inhibition of cell growth, and eventually cell death.
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12
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Villegas-Mendoza J, Cajal-Medrano R, Maske H. The Chemical Transformation of the Cellular Toxin INT (2-(4-Iodophenyl)-3-(4-Nitrophenyl)-5-(Phenyl) Tetrazolium Chloride) as an Indicator of Prior Respiratory Activity in Aquatic Bacteria. Int J Mol Sci 2019; 20:ijms20030782. [PMID: 30759783 PMCID: PMC6387158 DOI: 10.3390/ijms20030782] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Revised: 02/02/2019] [Accepted: 02/10/2019] [Indexed: 11/16/2022] Open
Abstract
In the ocean, the prokaryote respiration rates dominate the oxidation of organics, but the measurements may be biased due to pre-incubation size filtration and long incubation times. To overcome these difficulties, proxies for microbial respiration rates have been proposed, such as the in vitro and in vivo estimation of electron transport system rates (ETS) based on the reduction of tetrazolium salts. INT (2-(4-Iodophenyl)-3-(4-Nitrophenyl)-5-(Phenyl) Tetrazolium Chloride) is the most commonly applied tetrazolium salt, although it is toxic on time scales of less than 1 h for prokaryotes. This toxicity invalidates the interpretation of the rate of in vivo INT reduction to formazan as a proxy for oxygen consumption rates. We found that with aquatic bacteria, the amount of reduced INT (F; µmol/L formazan) showed excellent relation with the respiration rates prior to INT addition (R; O₂ µmol/L/hr), using samples of natural marine microbial communities and cultures of bacteria (V. harveyi) in batch and continuous cultures. We are here relating a physiological rate with the reductive potential of the poisoned cell with units of concentration. The respiration rate in cultures is well related to the cellular potential of microbial cells to reduce INT, despite the state of intoxication.
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Affiliation(s)
- Josué Villegas-Mendoza
- Facultad de Ciencias Marinas. UABC, Carretera Tijuana-Ensenada km 106, Ensenada, Baja California, CP 22860, Mexico.
| | - Ramón Cajal-Medrano
- CICESE, Carretera Tijuana-Ensenada No. 3918, Ensenada, Baja California, CP 22860, Mexico.
| | - Helmut Maske
- CICESE, Carretera Tijuana-Ensenada No. 3918, Ensenada, Baja California, CP 22860, Mexico.
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13
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Antibacterial effect and mechanism of anthocyanin rich Chinese wild blueberry extract on various foodborne pathogens. Food Control 2018. [DOI: 10.1016/j.foodcont.2018.07.012] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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14
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Tetrazolium salts and formazan products in Cell Biology: Viability assessment, fluorescence imaging, and labeling perspectives. Acta Histochem 2018; 120:159-167. [PMID: 29496266 DOI: 10.1016/j.acthis.2018.02.005] [Citation(s) in RCA: 363] [Impact Index Per Article: 51.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 02/14/2018] [Accepted: 02/14/2018] [Indexed: 01/11/2023]
Abstract
For many years various tetrazolium salts and their formazan products have been employed in histochemistry and for assessing cell viability. For the latter application, the most widely used are 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT), and 5-cyano-2,3-di-(p-tolyl)-tetrazolium chloride (CTC) for viability assays of eukaryotic cells and bacteria, respectively. In these cases, the nicotinamide-adenine-dinucleotide (NAD(P)H) coenzyme and dehydrogenases from metabolically active cells reduce tetrazolium salts to strongly colored and lipophilic formazan products, which are then quantified by absorbance (MTT) or fluorescence (CTC). More recently, certain sulfonated tetrazolium, which give rise to water-soluble formazans, have also proved useful for cytotoxicity assays. We describe several aspects of the application of tetrazolium salts and formazans in biomedical cell biology research, mainly regarding formazan-based colorimetric assays, cellular reduction of MTT, and localization and fluorescence of the MTT formazan in lipidic cell structures. In addition, some pharmacological and labeling perspectives of these compounds are also described.
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