1
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Ji C, Xu H, Yu H, Cui Z, Fan J, Zhai Z. An online monitoring device for measuring the concentration of four types of in-situ microorganisms by using the near-infrared band. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2024; 310:123895. [PMID: 38262294 DOI: 10.1016/j.saa.2024.123895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 01/12/2024] [Accepted: 01/13/2024] [Indexed: 01/25/2024]
Abstract
Using optical density at 600 nm (OD600) to measure the microbial concentration is a popular approach due to its advantages like quick response and non-destructive. However, the OD600 measurement might be affected by the metabolic pigment, and it would become invalid when the solution dilution is insufficient. To overcome these issues, we proposed to adopt a more robust wavelength at 890 nm to quantify the attenuation of transmission light. After selecting this light source, we designed the light path and the circuit of the online monitoring device. Meanwhile, the random forest algorithm was introduced for temperature compensation and improving the stability of the device. This device was verified by monitoring the microbial concentration of four strains (Yeast, Bacillus, Arthrobacter, and Escherichia coli). The experimental result suggested that the mean absolute percentage error reached 4.11 %, 4.28 %, 4.49 %, and 4.53 % respectively, which is helpful to improve the accuracy of microbial concentration measurement.
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Affiliation(s)
- Chengming Ji
- College of Artificial Intelligence, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Huanliang Xu
- College of Artificial Intelligence, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Hongfeng Yu
- College of Engineering, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Zhongli Cui
- College of Life Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Jiaqing Fan
- College of Plant Protection, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China
| | - Zhaoyu Zhai
- College of Artificial Intelligence, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China.
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2
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Viola RE, Parungao GG, Blumenthal RM. A growth-based assay using fluorescent protein emission to screen for S-adenosylmethionine synthetase inhibitors. Drug Dev Res 2024; 85:e22122. [PMID: 37819020 DOI: 10.1002/ddr.22122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 09/07/2023] [Accepted: 10/02/2023] [Indexed: 10/13/2023]
Abstract
The use of cell growth-based assays to identify inhibitory compounds is straightforward and inexpensive, but is also inherently insensitive and somewhat nonspecific. To overcome these limitations and develop a sensitive, specific cell-based assay, two different approaches were combined. To address the sensitivity limitation, different fluorescent proteins have been introduced into a bacterial expression system to serve as growth reporters. To overcome the lack of specificity, these protein reporters have been incorporated into a plasmid in which they are paired with different orthologs of an essential target enzyme, in this case l-methionine S-adenosyltransferase (MAT, AdoMet synthetase). Screening compounds that serve as specific inhibitors will reduce the growth of only a subset of strains, because these strains are identical, except for which target ortholog they carry. Screening several such strains in parallel not only reveals potential inhibitors but the strains also serve as specificity controls for one another. The present study makes use of an existing Escherichia coli strain that carries a deletion of metK, the gene for MAT. Transformation with these plasmids leads to a complemented strain that no longer requires externally supplied S-adenosylmethionine for growth, but its growth is now dependent on the activity of the introduced MAT ortholog. The resulting fluorescent strains provide a platform to screen chemical compound libraries and identify species-selective inhibitors of AdoMet synthetases. A pilot study of several chemical libraries using this platform identified new lead compounds that are ortholog-selective inhibitors of this enzyme family, some of which target the protozoal human pathogen Cryptosporidium parvum.
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Affiliation(s)
- Ronald E Viola
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio, USA
| | - Gwenn G Parungao
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, Ohio, USA
| | - Robert M Blumenthal
- Department of Medical Microbiology and Immunology, and Program in Bioinformatics, University of Toledo Health Sciences Campus, Toledo, Ohio, USA
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3
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Guo Y, Ma W, Song M, Wang W, Yin B, Gu R. Increase in Lactulose Content in a Hot-Alkaline-Based System through Fermentation with a Selected Lactic Acid Bacteria Strain Followed by the β-Galactosidase Catalysis Process. Foods 2023; 12:4317. [PMID: 38231767 DOI: 10.3390/foods12234317] [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: 10/17/2023] [Revised: 11/23/2023] [Accepted: 11/27/2023] [Indexed: 01/19/2024] Open
Abstract
In this study, lactic acid bacteria (LAB) fermentation and β-galactosidase catalysis methods were combined to increase the lactulose concentration and reduce the galactose and lactose content in a hot-alkaline-based system. The optimal conditions for chemical isomerization were 70 °C for 50 min for lactulose production, in which the concentration of lactulose was 31.3 ± 1.2%. Then, the selection and identification of LAB, which can utilize lactose and cannot affect lactulose content, were determined from 451 strains in the laboratory. It was found that Lactobacillus salivarius TM-2-8 had weak lactulose utilization and more robust lactose utilization. Lactobacillus rhamnosus grx.21 was weak in terms of lactulose utilization and strong in terms of galactose utilization. These two strains fermented the chemical isomerization system of lactulose to reduce the content of lactose and galactose. The results showed that the lactose concentration was 48.96 ± 2.92 g/L and the lactulose concentration was 59.73 ± 1. 8 g/L for fermentation lasting 18 h. The β-galactosidase was used to increase the content of lactulose in the fermented system at this time. The highest concentration of 74.89 ± 1.68 g/L lactulose was obtained at an enzymatic concentration of 3 U/mL and catalyzed at 50 °C for 3 h by β-galactosidase.
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Affiliation(s)
- Yaozu Guo
- College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, China
- Jiangsu Dairy Biotechnology Engineering Research Center, Kang Yuan Dairy Co., Ltd., Yangzhou University, Yangzhou 225127, China
| | - Wenlong Ma
- College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, China
| | - Manxi Song
- College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, China
| | - Wenqiong Wang
- College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, China
| | - Boxing Yin
- College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, China
- Jiangsu Dairy Biotechnology Engineering Research Center, Kang Yuan Dairy Co., Ltd., Yangzhou University, Yangzhou 225127, China
| | - Ruixia Gu
- College of Food Science and Engineering, Yangzhou University, Yangzhou 225127, China
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4
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Tiwari S, Nizet O, Dillon N. Development of a high-throughput minimum inhibitory concentration (HT-MIC) testing workflow. Front Microbiol 2023; 14:1079033. [PMID: 37303796 PMCID: PMC10249070 DOI: 10.3389/fmicb.2023.1079033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 04/24/2023] [Indexed: 06/13/2023] Open
Abstract
The roots of the minimum inhibitory concentration (MIC) determination go back to the early 1900s. Since then, the test has undergone modifications and advancements in an effort to increase its dependability and accuracy. Although biological investigations use an ever-increasing number of samples, complicated processes and human error sometimes result in poor data quality, which makes it challenging to replicate scientific conclusions. Automating manual steps using protocols decipherable by machine can ease procedural difficulties. Originally relying on manual pipetting and human vision to determine the results, modern broth dilution MIC testing procedures have incorporated microplate readers to enhance sample analysis. However, current MIC testing procedures are unable to simultaneously evaluate a large number of samples efficiently. Here, we have created a proof-of-concept workflow using the Opentrons OT-2 robot to enable high-throughput MIC testing. We have further optimized the analysis by incorporating Python programming for MIC assignment to streamline the automation. In this workflow, we performed MIC tests on four different strains, three replicates per strain, and analyzed a total of 1,152 wells. Comparing our workflow to a conventional plate MIC procedure, we find that the HT-MIC method is 800% faster while simultaneously boasting a 100% accuracy. Our high-throughput MIC workflow can be adapted in both academic and clinical settings since it is faster, more efficient, and as accurate than many conventional methods.
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Affiliation(s)
- Suman Tiwari
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX, United States
| | - Oliver Nizet
- La Jolla Country Day School, La Jolla, CA, United States
| | - Nicholas Dillon
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX, United States
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5
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Jeong Y, Vyas K, Irudayaraj J. Toxicity of per- and polyfluoroalkyl substances to microorganisms in confined hydrogel structures. JOURNAL OF HAZARDOUS MATERIALS 2023; 456:131672. [PMID: 37236111 DOI: 10.1016/j.jhazmat.2023.131672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 05/05/2023] [Accepted: 05/20/2023] [Indexed: 05/28/2023]
Abstract
Per- and polyfluoroalkyl substances (PFAS) as a group of environmentally persistent synthetic chemicals has been widely used in industrial and consumer products. Bioaccumulation studies have documented the adverse effects of PFAS in various living organisms. Despite the large number of studies, experimental approaches to evaluate the toxicity of PFAS on bacteria in a biofilm-like niche as structured microbial communities are sparse. This study suggests a facile approach to query the toxicity of PFOS and PFOA on bacteria (Escherichia coli K12 MG1655 strain) in a biofilm-like niche provided by hydrogel-based core-shell beads. Our study shows that E. coli MG1655 upon complete confinement in hydrogel beads exhibit altered physiological characteristics of viability, biomass, and protein expression, compared to their susceptible counterpart cultivated under planktonic conditions. We find that soft-hydrogel engineering platforms may provide a protective role for microorganisms from environmental contaminants, depending on the size or thickness of the protective/barrier layer. We expect our study to provide insights on the toxicity of environmental contaminants on organisms under encapsulated conditions that could potentially be useful for toxicity screening and in evaluating ecological risk of soil, plant, and mammalian microbiome.
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Affiliation(s)
- Yoon Jeong
- Department of Bioengineering, University of Illinois Urbana-Champaign, Urbana, IL, USA; Cancer Center at Illinois, University of Illinois Urbana-Champaign, Urbana, IL, USA; Biomedical Research Center, Mills Breast Cancer Institute, Carle Foundation Hospital, Urbana, IL, USA
| | - Khushali Vyas
- School of Molecular and Cellular Biology, University of Illinois Urbana-Champaign, Urbana, IL, USA
| | - Joseph Irudayaraj
- Department of Bioengineering, University of Illinois Urbana-Champaign, Urbana, IL, USA; Cancer Center at Illinois, University of Illinois Urbana-Champaign, Urbana, IL, USA; Biomedical Research Center, Mills Breast Cancer Institute, Carle Foundation Hospital, Urbana, IL, USA; Carle R. Woese Institute for Genomic Biology, Beckman Institute, Holonyak Micro and Nanotechnology Laboratory, Urbana, IL, USA.
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6
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Pratap Singh D, Packirisamy G. Biopolymer based edible coating for enhancing the shelf life of horticulture products. FOOD CHEMISTRY. MOLECULAR SCIENCES 2022; 4:100085. [PMID: 35415673 PMCID: PMC8991528 DOI: 10.1016/j.fochms.2022.100085] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 01/02/2022] [Accepted: 02/04/2022] [Indexed: 12/16/2022]
Abstract
Silk-fibroin based edible coating to enhance the shelf-life of perishable food This edible coating iscost-effective, biodegradable, and non-toxic. Coating can be prepared in two ways: nanofiber-based coating and dip-coating. Coating maintainstexture,stiffness and nutrient content of food for longtime.
As per the report of the United Nations, half of the fruits and vegetables loses annually. Industries are trying to reduce the postharvest loss by using coatings. Wax coating is the most preferred way to preserve fruits and veggies. Sometimes wax is mixed with some chemical compounds that are known to be carcinogenic. Recently many edible films have been developed using natural polymers to enhance the shelf life of food. The edible films act as a barrier between the food and the external environment to prevent the direct interaction of food with atmospheric gases and microbes, which reduce the rate of respiration, keeping the food fresh for an extended period. But, the cost of edible biofilms is high and restricted at the industrial level; the local fruits and vegetable vendors are not able to buy such costly biofilms. We have developed the solution for dip-coating and nanofiber coating using a blend of silk fibroin, PVA, honey and curcumin, which is a cost-effective method for fruits and vegetable vendors. The material used for coating is FDA approved. The techniques utilized for synthesizing the biofilm are electrospinning and dip-coating. Coating found to increase the shelf-life of fruits and vegetables.
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Affiliation(s)
- Dravin Pratap Singh
- Nanobiotechnology Laboratory, Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
| | - Gopinath Packirisamy
- Nanobiotechnology Laboratory, Centre for Nanotechnology, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India.,Department of Biosciences and Bioengineering, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
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7
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Biofilm Detection by a Fiber-Tip Ball Resonator Optical Fiber Sensor. BIOSENSORS 2022; 12:bios12070481. [PMID: 35884284 PMCID: PMC9313161 DOI: 10.3390/bios12070481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2022] [Revised: 06/29/2022] [Accepted: 06/29/2022] [Indexed: 11/16/2022]
Abstract
Bacterial biofilms are one of the most important challenges that modern medicine faces due to the difficulties of diagnosis, antibiotic resistance, and protective mechanisms against aggressive environments. For these reasons, methods that ensure the inexpensive and rapid or real-time detection of biofilm formation on medical devices are needed. This study examines the possibilities of using optical- and fiber-based biosensors to detect and analyze early bacterial biofilms. In this study, the biofilm-forming model organism Pseudomonas aeruginosa was inoculated on the surface of the optical sensor and allowed to attach for 2 h. The biosensors were made by a fiber-tip ball resonator, fabricated through a CO2 laser splicer on a single-mode fiber, forming a weak reflective spectrum. An optical backscatter reflectometer was used to measure the refractive index detected by the sensors during different growth periods. The early biofilm concentration was determined by crystal violet (CV) binding assay; however, such a concentration was lower than the detection limit of this assay. This work presents a new approach of biofilm sensing in the early attachment stage with a low limit of detection up to 10−4 RIU (refractive index units) or 35 ± 20 × 103 CFU/mL (colony formed units).
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8
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Scott TJ, Queller DC, Strassmann JE. Context dependence in the symbiosis between
Dictyostelium discoideum
and
Paraburkholderia. Evol Lett 2022; 6:245-254. [PMID: 35784451 PMCID: PMC9233174 DOI: 10.1002/evl3.281] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 02/22/2022] [Accepted: 04/01/2022] [Indexed: 01/13/2023] Open
Affiliation(s)
- Trey J. Scott
- Department of Biology Washington University in St. Louis St. Louis Missouri 63130
| | - David C. Queller
- Department of Biology Washington University in St. Louis St. Louis Missouri 63130
| | - Joan E. Strassmann
- Department of Biology Washington University in St. Louis St. Louis Missouri 63130
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9
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Jiang S, Li Q, Jia W, Wang F, Cao X, Shen X, Yao Z. Expanding the application of ion exchange resins for the preparation of antimicrobial membranes to control foodborne pathogens. CHEMOSPHERE 2022; 295:133963. [PMID: 35167836 DOI: 10.1016/j.chemosphere.2022.133963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 02/09/2022] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
Although ion exchange resins (IERs) have been extensively adopted in water treatment, there are no reports on the application thereof for synthesizing antibacterial materials against pathogenic bacteria. The present study is the first in which the ion exchange characteristic of IERs was utilized to introduce silver ions that possess efficient antibacterial properties. The resulting antibacterial materials were incorporated into polylactic acid (PLA) and/or polybutylene adipate terephthalate (PBAT) to prepare antibacterial membranes. XPS spectra revealed the occurrence of in-situ reduction of silver ions to metallic silver, which was preferable since the stability of silver in the materials was improved. EDS mapping analysis indicated that the distribution of silver was consistent with the distribution of sulfur in the membranes, verifying the ion exchange methodology proposed in the present study. To investigate the antibacterial performance of the prepared membranes, zone of inhibition tests and bacteria-killing tests were performed. The results revealed that neither bare polymeric membranes of PLA and PBAT nor IER-incorporated polymeric membranes exhibited noticeable antibacterial activities. In comparison, the antibacterial membranes demonstrated effective and sustainable antibacterial activities against pathogenic bacteria Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). The prepared antibacterial membranes exhibited potential in food-related applications such as food packaging to delay food spoilage due to microbial growth.
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Affiliation(s)
- Shanxue Jiang
- School of Ecology and Environment, Beijing Technology and Business University, Beijing, 100048, China; State Environmental Protection Key Laboratory of Food Chain Pollution Control, Beijing Technology and Business University, Beijing, 100048, China
| | - Qirun Li
- School of Ecology and Environment, Beijing Technology and Business University, Beijing, 100048, China; State Environmental Protection Key Laboratory of Food Chain Pollution Control, Beijing Technology and Business University, Beijing, 100048, China
| | - Wenting Jia
- School of Ecology and Environment, Beijing Technology and Business University, Beijing, 100048, China; State Environmental Protection Key Laboratory of Food Chain Pollution Control, Beijing Technology and Business University, Beijing, 100048, China
| | - Fang Wang
- School of Ecology and Environment, Beijing Technology and Business University, Beijing, 100048, China; State Environmental Protection Key Laboratory of Food Chain Pollution Control, Beijing Technology and Business University, Beijing, 100048, China
| | - Xinyue Cao
- School of Ecology and Environment, Beijing Technology and Business University, Beijing, 100048, China; State Environmental Protection Key Laboratory of Food Chain Pollution Control, Beijing Technology and Business University, Beijing, 100048, China
| | - Xianbao Shen
- School of Ecology and Environment, Beijing Technology and Business University, Beijing, 100048, China; State Environmental Protection Key Laboratory of Food Chain Pollution Control, Beijing Technology and Business University, Beijing, 100048, China
| | - Zhiliang Yao
- School of Ecology and Environment, Beijing Technology and Business University, Beijing, 100048, China; State Environmental Protection Key Laboratory of Food Chain Pollution Control, Beijing Technology and Business University, Beijing, 100048, China.
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10
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KAREENA A, SIRIPONGVUTIKORN S, USAWAKESMANEE W, WICHIENCHOT S. In vitro evaluation of probiotic bacteria and yeast growth, pH changes and metabolites produced in a pure culture system using protein base products with various added carbon sources. FOOD SCIENCE AND TECHNOLOGY 2022. [DOI: 10.1590/fst.18321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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11
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Harhala M, Gembara K, Miernikiewicz P, Owczarek B, Kaźmierczak Z, Majewska J, Nelson DC, Dąbrowska K. DNA Dye Sytox Green in Detection of Bacteriolytic Activity: High Speed, Precision and Sensitivity Demonstrated With Endolysins. Front Microbiol 2021; 12:752282. [PMID: 34759903 PMCID: PMC8575126 DOI: 10.3389/fmicb.2021.752282] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 09/24/2021] [Indexed: 12/03/2022] Open
Abstract
Introduction: Increasing number of deaths from multi-drug resistant bacterial infections has caused both the World Health Organization and the Centers for Disease Control and Prevention to repeatedly call for development of new, non-traditional antibacterial treatments. Antimicrobial enzymes, including those derived from bacteriophages, known as endolysins or enzybiotics, are considered promising solutions among the emerging therapies. These naturally occurring proteins specifically destroy bacterial cell walls (peptidoglycan) and as such, are capable of killing several logs of bacteria within minutes. Some endolysins cause lysis of a wide range of susceptible bacteria, including both Gram-positive and Gram-negative organisms, whereas other endolysins are species- or even strain-specific. To make wide use of endolysins as antibacterial agents, some basic research issues remain to be clarified or addressed. Currently available methods for testing endolysin kinetics are indirect, require large numbers of bacteria, long incubation times and are affected by technical problems or limited reproducibility. Also, available methods are focused more on enzymatic activity rather than killing efficiency which is more relevant from a medical perspective. Results: We show a novel application of a DNA dye, SYTOX Green. It can be applied in comprehensive, real-time and rapid measurement of killing efficiency, lytic activity, and susceptibility of a bacterial population to lytic enzymes. Use of DNA dyes shows improved reaction times, higher sensitivity in low concentrations of bacteria, and independence of bacterial growth. Our data show high precision in lytic activity and enzyme efficiency measurements. This solution opens the way to the development of new, high throughput, precise measurements and tests in variety of conditions, thus unlocking new possibilities in development of novel antimicrobials and analysis of bacterial samples.
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Affiliation(s)
- Marek Harhala
- Laboratory of Phage Molecular Biology, Department of Phage Therapy, Hirszfeld Institute of Immunology and Experimental Therapy, Wrocław, Poland.,Research and Development Centre, Regional Specialist Hospital in Wrocław, Wrocław, Poland
| | - Katarzyna Gembara
- Laboratory of Phage Molecular Biology, Department of Phage Therapy, Hirszfeld Institute of Immunology and Experimental Therapy, Wrocław, Poland.,Research and Development Centre, Regional Specialist Hospital in Wrocław, Wrocław, Poland
| | - Paulina Miernikiewicz
- Laboratory of Phage Molecular Biology, Department of Phage Therapy, Hirszfeld Institute of Immunology and Experimental Therapy, Wrocław, Poland
| | - Barbara Owczarek
- Bacteriophage Laboratory, Department of Phage Therapy, Hirszfeld Institute of Immunology and Experimental Therapy, Wrocław, Poland
| | - Zuzanna Kaźmierczak
- Laboratory of Phage Molecular Biology, Department of Phage Therapy, Hirszfeld Institute of Immunology and Experimental Therapy, Wrocław, Poland.,Research and Development Centre, Regional Specialist Hospital in Wrocław, Wrocław, Poland
| | - Joanna Majewska
- Laboratory of Phage Molecular Biology, Department of Phage Therapy, Hirszfeld Institute of Immunology and Experimental Therapy, Wrocław, Poland
| | - Daniel C Nelson
- Institute for Bioscience and Biotechnology Research, University of Maryland, Rockville, MD, United States
| | - Krystyna Dąbrowska
- Laboratory of Phage Molecular Biology, Department of Phage Therapy, Hirszfeld Institute of Immunology and Experimental Therapy, Wrocław, Poland.,Research and Development Centre, Regional Specialist Hospital in Wrocław, Wrocław, Poland
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12
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Bormans S, Oudebrouckx G, Vandormael P, Vandenryt T, Wagner P, Somers V, Thoelen R. Pulsed Thermal Method for Monitoring Cell Proliferation in Real-Time. SENSORS (BASEL, SWITZERLAND) 2021; 21:2440. [PMID: 33916287 PMCID: PMC8036761 DOI: 10.3390/s21072440] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/26/2021] [Accepted: 03/30/2021] [Indexed: 11/16/2022]
Abstract
The study of cell proliferation is of great importance for medical and biological research, as well as for industrial applications. To render the proliferation process accurately over time, real-time cell proliferation assay methods are required. This work presents a novel real-time and label-free approach for monitoring cell proliferation by continuously measuring changes in thermal properties that occur at the sensor interface during the process. The sensor consists of a single planar resistive structure deposited on a thin foil substrate, integrated at the bottom of a cell culture reservoir. During measurement, the structure is excited with square wave current pulses. Meanwhile, the temperature-induced voltage change measured over the structure is used to derive variations in the number of cells at the interface. This principle is demonstrated first by performing cell sedimentation measurements to quantify the presence of cells at the sensor interface in the absence of cell growth. Later, cell proliferation experiments were performed, whereby parameters such as the available nutrient content and the cell starting concentration were modified. Results from these experiments show that the thermal-based sensor is able to accurately measure variations in the number of cells at the interface. Moreover, the influence of the modified parameters could be observed in the obtained proliferation curves. These findings highlight the potential for the presented thermal method to be incorporated in a standardized well plate format for high-throughput monitoring of cell proliferation.
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Affiliation(s)
- Seppe Bormans
- Institute for Materials Research (IMO), Hasselt University, 3500 Hasselt, Belgium; (G.O.); (T.V.); (R.T.)
- IMEC vzw, Division IMOMEC, 3590 Diepenbeek, Belgium
| | - Gilles Oudebrouckx
- Institute for Materials Research (IMO), Hasselt University, 3500 Hasselt, Belgium; (G.O.); (T.V.); (R.T.)
- IMEC vzw, Division IMOMEC, 3590 Diepenbeek, Belgium
| | - Patrick Vandormael
- Biomedical Research Institute (BIOMED), School of Life Sciences, Hasselt University, 3500 Hasselt, Belgium; (P.V.); (V.S.)
| | - Thijs Vandenryt
- Institute for Materials Research (IMO), Hasselt University, 3500 Hasselt, Belgium; (G.O.); (T.V.); (R.T.)
- IMEC vzw, Division IMOMEC, 3590 Diepenbeek, Belgium
| | - Patrick Wagner
- Laboratory for Soft Matter and Biophysics, KU Leuven, 3001 Leuven, Belgium;
| | - Veerle Somers
- Biomedical Research Institute (BIOMED), School of Life Sciences, Hasselt University, 3500 Hasselt, Belgium; (P.V.); (V.S.)
| | - Ronald Thoelen
- Institute for Materials Research (IMO), Hasselt University, 3500 Hasselt, Belgium; (G.O.); (T.V.); (R.T.)
- IMEC vzw, Division IMOMEC, 3590 Diepenbeek, Belgium
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13
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Zhang P, Zhang Y, Zhao Y, Song Y, Niu C, Sui Z, Wang J, Yang R, Wei D. Calibration of an Upconverting Phosphor-Based Quantitative Immunochromatographic Assay for Detecting Yersinia pestis, Brucella spp., and Bacillus anthracis Spores. Front Cell Infect Microbiol 2020; 10:147. [PMID: 32391285 PMCID: PMC7192967 DOI: 10.3389/fcimb.2020.00147] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 03/19/2020] [Indexed: 12/14/2022] Open
Abstract
Yersinia pestis, Brucella spp., and Bacillus anthracis are pathogens that can cause infectious zoonotic diseases with high mortality rates. An upconverting phosphor-based quantitative immunochromatographic (UPT-LF) assay, a point-of-care testing method suitable for resource-limited areas, was calibrated to quantitatively detect pathogenic bacteria. The bacterial purity or activity were ensured via staining methods and growth curves, respectively. Growth assays showed that the classic plate-counting method underestimated bacterial numbers compared with the bacterial counting method recommended by the reference material of the National Institutes for Food and Drug Control, China. The detection results of the UPT-LF assay differed significantly between the bacterial cultures in liquid and solid media and between different strains. Accelerated stability assessments and freeze-thaw experiments showed that the stability of the corresponding antigens played an important role in calibrating the UPT-LF assay. In this study, a new calibration system was developed for quantitative immunochromatography for detecting pathogenic bacteria. The results demonstrated the necessity of calibration for standardizing point-of-care testing methods.
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Affiliation(s)
- Pingping Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,Beijing Key Laboratory of POCT for Bioemergency and Clinic, Beijing, China
| | - Yuanyuan Zhang
- Division of Tuberculosis Vaccines, National Institutes for Food and Drug Control, Beijing, China
| | - Yong Zhao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,Beijing Key Laboratory of POCT for Bioemergency and Clinic, Beijing, China
| | - Yajun Song
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,Beijing Key Laboratory of POCT for Bioemergency and Clinic, Beijing, China
| | - Chunyan Niu
- Center for Advanced Measurements Science, National Institutes of Metrology, Beijing, China
| | - Zhiwei Sui
- Center for Advanced Measurements Science, National Institutes of Metrology, Beijing, China
| | - Jing Wang
- Center for Advanced Measurements Science, National Institutes of Metrology, Beijing, China
| | - Ruifu Yang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China.,Beijing Key Laboratory of POCT for Bioemergency and Clinic, Beijing, China
| | - Dong Wei
- Division of Tuberculosis Vaccines, National Institutes for Food and Drug Control, Beijing, China
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14
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Przekwas J, Wiktorczyk N, Budzyńska A, Wałecka-Zacharska E, Gospodarek-Komkowska E. Ascorbic Acid Changes Growth of Food-Borne Pathogens in the Early Stage of Biofilm Formation. Microorganisms 2020; 8:E553. [PMID: 32290491 PMCID: PMC7232495 DOI: 10.3390/microorganisms8040553] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Revised: 04/01/2020] [Accepted: 04/09/2020] [Indexed: 12/22/2022] Open
Abstract
Since bacterial biofilm may contribute to the secondary contamination of food during the manufacturing/processing stage there is a need for new methods allowing its effective eradication. Application of food additives such as vitamin C already used in food industry as antioxidant food industry antioxidants may be a promising solution. The aim of this research was evaluation of the impact of vitamin C (ascorbic acid), in a range of concentrations 2.50 µg mL-1-25.0 mg mL-1, on biofilms of Staphylococcus aureus, Escherichia coli, and Listeria monocytogenes strains isolated from food. The efficacy of ascorbic acid was assessed based on the reduction of optical density (λ = 595 nm). The greatest elimination of the biofilm was achieved at the concentration of vitamin C of 25.0 mg mL-1. The effect of the vitamin C on biofilm, however, was strain dependent. The concentration of 25.0 mg mL-1 reduced 93.4%, 74.9%, and 40.5% of E. coli, L. monocytogenes, and S. aureus number, respectively. For E. coli and S. aureus lower concentrations were ineffective. In turn, for L. monocytogenes the biofilm inhibition was observed even at the concentration of 0.25 mg mL-1. The addition of vitamin C may be helpful in the elimination of bacterial biofilms. Nonetheless, some concentrations can induce growth of the pathogens, posing risk for the consumers' health.
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Affiliation(s)
- Jana Przekwas
- Department of Microbiology, Nicolaus Copernicus University in Toruń, Ludwik Rydygier Collegium Medicum, 9 Maria Skłodowska-Curie Street, 85-094 Bydgoszcz, Poland
| | - Natalia Wiktorczyk
- Department of Microbiology, Nicolaus Copernicus University in Toruń, Ludwik Rydygier Collegium Medicum, 9 Maria Skłodowska-Curie Street, 85-094 Bydgoszcz, Poland
| | - Anna Budzyńska
- Department of Microbiology, Nicolaus Copernicus University in Toruń, Ludwik Rydygier Collegium Medicum, 9 Maria Skłodowska-Curie Street, 85-094 Bydgoszcz, Poland
| | - Ewa Wałecka-Zacharska
- Department of Food Hygiene and Consumer Health, Wrocław University of Environmental and Life Sciences, 31 C.K. Norwida St., 50-375 Wrocław, Poland
| | - Eugenia Gospodarek-Komkowska
- Department of Microbiology, Nicolaus Copernicus University in Toruń, Ludwik Rydygier Collegium Medicum, 9 Maria Skłodowska-Curie Street, 85-094 Bydgoszcz, Poland
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15
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Li P, Tian Y, Ke XM, Tan QC, Han X, Ma HY, Pei J, Lin JZ, Xu RC, Han L, Yang M, Zhang DK. Amphiphilic Block Copolymers: A Novel Substance for Bitter-Masking in Aqueous Solutions. Mol Pharm 2020; 17:1586-1595. [PMID: 32186879 DOI: 10.1021/acs.molpharmaceut.9b01296] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
It is a challenging task to suppress the bitterness of liquid preparations, especially for children. Bitter molecules are highly dispersible in liquids, leading to a strong and instant stimulation of the bitter receptors. At present, there is no effective way to correct this issue except for adding sweeteners, resulting in an unsatisfying taste. Based on the three-point contact theory, which is a universally accepted mechanism of bitterness formation, a new idea and application of amphiphilic block copolymers (ABCs) for bitterness suppression was proposed for the first time. We found that ABCs could widely inhibit the bitterness of four typical bitter substances. The mechanism is that ABCs self-assemble to form association colloids, which attract bitter components and reduce their distribution in the molecular form in solution. The bitter components were demonstrated to automatically embed in the spiral hydrophobic cavity of the hydrophobic chain of the ABCs, and their special interaction dispersed the positive electrostatic potential of bitter groups. The combination did not affect the pharmacokinetic parameters and pharmacodynamics of bitter drugs. These findings highlight the novel application of ABCs for the inhibition of bitterness and illuminate the underlying inhibition mechanisms.
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Affiliation(s)
- Pan Li
- State Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Yin Tian
- State Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Xiu-Mei Ke
- State Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China.,School of Basic Medical Sciences, Jiujiang University, Jiujiang 332005, China
| | - Qing-Chu Tan
- State Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Xue Han
- Shool of Pharmacy, Chengdu Medical College, Chengdu 610083, China
| | - Hong-Yan Ma
- State Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Jin Pei
- State Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Jun-Zhi Lin
- Central Laboratory, The Teaching Hospital of Chengdu University of Traditional Chinese Medicine, Chengdu 610072, China
| | - Run-Chun Xu
- State Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Li Han
- State Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
| | - Ming Yang
- Jiangxi University of Traditional Chinese Medicine, Nanchang 330004, China
| | - Ding-Kun Zhang
- State Key Laboratory Breeding Base of Systematic Research, Development and Utilization of Chinese Medicine Resources, School of Pharmacy, Chengdu University of Traditional Chinese Medicine, Chengdu 611137, China
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16
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A rapid method to quantify the biomass of viable Acidithiobacillus ferrooxidans in iron-based bioleaching matrix of sewage sludge. Biochem Eng J 2019. [DOI: 10.1016/j.bej.2019.107360] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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17
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Lucidi M, Marsan M, Pudda F, Pirolo M, Frangipani E, Visca P, Cincotti G. Geometrical-optics approach to measure the optical density of bacterial cultures using a LED-based photometer. BIOMEDICAL OPTICS EXPRESS 2019; 10:5600-5610. [PMID: 31799033 PMCID: PMC6865109 DOI: 10.1364/boe.10.005600] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Revised: 09/09/2019] [Accepted: 10/02/2019] [Indexed: 05/11/2023]
Abstract
We develop a suitable geometrical-optics approach and demonstrate that it is possible to measure the optical density (OD) of bacterial cultures using a light emitting diode (LED)-based photometer. We measure both attenuation and spot-size variation, and we compensate for diffraction and stray-light impairment related to the incoherent source and large detection area. The approach is validated for different concentrations of two bacterial species, Escherichia coli and Staphylococcus aureus, that present different shapes and clustering organization.
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Affiliation(s)
- Massimiliano Lucidi
- Engineering Department, University Roma Tre, via Vito Volterra 62, 00146 Rome, Italy
| | - Marco Marsan
- Engineering Department, University Roma Tre, via Vito Volterra 62, 00146 Rome, Italy
| | - Francesco Pudda
- Engineering Department, University Roma Tre, via Vito Volterra 62, 00146 Rome, Italy
| | - Mattia Pirolo
- Department of Science, University Roma Tre, viale Marconi 446, 00146 Rome, Italy
| | - Emanuela Frangipani
- Department of Biomolecular Sciences, University of Urbino Carlo Bo, Urbino, Italy
| | - Paolo Visca
- Department of Science, University Roma Tre, viale Marconi 446, 00146 Rome, Italy
| | - Gabriella Cincotti
- Engineering Department, University Roma Tre, via Vito Volterra 62, 00146 Rome, Italy
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18
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Meyers A, Furtmann C, Gesing K, Tozakidis IEP, Jose J. Cell density-dependent auto-inducible promoters for expression of recombinant proteins in Pseudomonas putida. Microb Biotechnol 2019; 12:1003-1013. [PMID: 31237428 PMCID: PMC6680623 DOI: 10.1111/1751-7915.13455] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 06/05/2019] [Accepted: 06/05/2019] [Indexed: 02/06/2023] Open
Abstract
Inducible promoters such as Plac are of limited usability for industrial protein production with Pseudomonas putida. We therefore utilized cell density-dependent auto-inducible promoters for recombinant gene expression in P. putida KT2440 based on the RoxS/RoxR Quorum Sensing (QS) system of the bacterium. To this end, genetic regions upstream of the RoxS/RoxR-regulated genes ddcA (PR ox132 ) and PP_3332 (PR ox306 ) were inserted into plasmids that mediated the expression of superfolder green fluorescent protein (sfGFP) and surface displayed mCherry, confirming their promoter functionalities. Mutation of the Pribnow box of PR ox306 to the σ70 consensus sequence (PR ox3061 ) resulted in a more than threefold increase of sfGFP production. All three promoters caused cell density-dependent expression, starting transcription at optical densities (OD578 ) of approximately 1.0 (PR ox132 , PR ox306 ) or 0.7 (PR ox3061 ) as determined by RT-qPCR. The QS dependency of PR ox306 was further shown by cultivating P. putida in media that had already been used for cultivation and thus contained bacterial signal molecules. The longer P. putida had grown in these media before, the earlier protein expression in freshly inoculated P. putida appeared with PR ox306 . This confirmed previous findings that a bacterial compound accumulates within the culture and induces protein expression.
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Affiliation(s)
- Annika Meyers
- Institut für Pharmazeutische und Medizinische ChemieWestfälische Wilhelms‐Universität MünsterPharmaCampus, Corrensstr. 4848149MünsterGermany
| | - Christoph Furtmann
- Institut für Pharmazeutische und Medizinische ChemieWestfälische Wilhelms‐Universität MünsterPharmaCampus, Corrensstr. 4848149MünsterGermany
| | - Katrin Gesing
- Institut für Pharmazeutische und Medizinische ChemieWestfälische Wilhelms‐Universität MünsterPharmaCampus, Corrensstr. 4848149MünsterGermany
| | - Iasson E. P. Tozakidis
- Institut für Pharmazeutische und Medizinische ChemieWestfälische Wilhelms‐Universität MünsterPharmaCampus, Corrensstr. 4848149MünsterGermany
| | - Joachim Jose
- Institut für Pharmazeutische und Medizinische ChemieWestfälische Wilhelms‐Universität MünsterPharmaCampus, Corrensstr. 4848149MünsterGermany
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19
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Wu R, Chen G, Pan S, Zeng J, Liang Z. Cost-effective fibrinolytic enzyme production by Bacillus subtilis WR350 using medium supplemented with corn steep powder and sucrose. Sci Rep 2019; 9:6824. [PMID: 31048760 PMCID: PMC6497689 DOI: 10.1038/s41598-019-43371-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 04/23/2019] [Indexed: 01/24/2023] Open
Abstract
The goal of this study was to develop a cheap and simple medium and to optimize fermentation parameters for fibrinolytic enzyme production by Bacillus subtilis WR350. A low-cost medium containing 35 g/L sucrose, 20 g/L corn steep powder and 2 g/L MgSO4·7H2O was developed via single-factor and orthogonal experiments. A cheap nitrogen source, corn steep powder, was used to replace the soy peptone present in the initial medium. The highest fibrinolytic activity of 5865 U/mL was achieved using the optimized medium in a 100-L fermenter with an aeration rate of 1.0 vvm and an agitation speed of 200 rpm. The resulting enzyme yield was among the highest described in the literature with respect to fibrinolytic activity, as determined by the fibrin plate method. Techno-economic evaluation indicated that the cost of the optimized medium was only 8.5% of the cost of the initial medium, and the total fermentation cost of fibrinolytic enzyme production using the optimized medium was 23.35% of the cost of using the initial medium.
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Affiliation(s)
- Rui Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Microorganism and Enzyme Research Center of Engineering Technology; College of Life Science and Technology; Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Guiguang Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Microorganism and Enzyme Research Center of Engineering Technology; College of Life Science and Technology; Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Shihan Pan
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Microorganism and Enzyme Research Center of Engineering Technology; College of Life Science and Technology; Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Jingjing Zeng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Microorganism and Enzyme Research Center of Engineering Technology; College of Life Science and Technology; Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China
| | - Zhiqun Liang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, Guangxi Microorganism and Enzyme Research Center of Engineering Technology; College of Life Science and Technology; Guangxi University, 100 Daxue Road, Nanning, 530004, Guangxi, China.
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