Extracellular polymeric substances excreted by anammox sludge act as a barrier for As(III) invasion: Binding property and interaction mechanism

AbstractThe specific roles of extracellular polymeric substances (EPS) and how factors influenced EPS’s roles during U(VI) immobilization are still unclear. In this study, high content of U with the main form of nanoparticles was detected in EPS, accounting for 10–42% of total U(VI) removal. EPS might be utilized as energy source or even as electron donors when external carbon source was unavailable. The influencing degree of each experimental parameter to uranium (U) removal process was elucidated. The influential priority to U(IV)/U(VI) ratios in sludge was as follows: acetate, U(VI), and nitrate. The influential priority to total EPS contents was as follows: U(VI), nitrate and acetate. The complex interaction mechanism between U(VI) and EPS in the U immobilization process was proposed, which might involve three ways including biosorption, bioreduction and bioprecipitation. These results indicate important and various roles of EPS in U(VI) immobilization.

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Optimization for extracellular polymeric substances extraction of microbial aggregates

Water Science & Technology ◽

10.2166/wst.2015.043 ◽

2015 ◽

Vol 71 (7) ◽

pp. 1106-1112 ◽

Cited By ~ 6

Author(s):

Liang Zhu ◽

Haitian Yu ◽

Yimei Liu ◽

Hanying Qi ◽

Xiangyang Xu

Keyword(s):

Humic Acid ◽

Extracellular Polymeric Substances ◽

Three Dimensional ◽

Interaction Mechanism ◽

Extraction Methods ◽

Aerobic Granules ◽

Excitation Emission Matrix ◽

Cation Exchange Resins ◽

Heat Method ◽

Exchange Resins

The extracellular polymeric substances (EPS) are important macromolecular components in microbial aggregates. The three EPS extraction methods – ultrasound + cation exchange resins (CER) + sulfide, ultrasound + formamide + NaOH, and ultrasound + heat – were investigated in the study, and the component differences of extracted EPS from the loose flocs and dense aerobic granules were compared using chemical analysis and three-dimensional excitation-emission matrix (3D-EEM). Results showed that the contents of EPS were extracted effectively by ultrasound + formamide + NaOH and ultrasound + heat methods, and the ultrasound + CER + sulfide method did not extract the polysaccharides (PS) or protein (PN) contents from the sludge samples. The 3D-EEM analysis indicated that the nature of peak B/D, peak C/E/F, and peak A/G were attributed to PN-like, humic acid-like and fulvic acid-like fluorophores. All fluorophores can be detected from the EPS extracted through the ultrasound + heat method. Hopefully this will provide more information about the EPS interaction mechanism of microbial aggregates.

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Response of extracellular polymeric substances to the toxicity of 2,4-dichlorophenol in aerobic granular sludge system: production and interaction mechanism

RSC Advances ◽

10.1039/c5ra03076e ◽

2015 ◽

Vol 5 (42) ◽

pp. 33016-33022 ◽

Cited By ~ 12

Author(s):

Yifan Wang ◽

Dong Wei ◽

Kai Li ◽

Bingfeng Wang ◽

Li Shi ◽

...

Keyword(s):

Extracellular Polymeric Substances ◽

Interaction Mechanism ◽

Granular Sludge ◽

Aerobic Granular Sludge ◽

System P

The objective of this study was to investigate the response of extracellular polymeric substances (EPS) to the toxicity of 2,4-dichlorophenol (2,4-DCP) in an aerobic granular sludge system.

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Distributed Cooperative Control Based on Dynamic Following Interaction Mechanism for UUV Swarm

2020 39th Chinese Control Conference (CCC) ◽

10.23919/ccc50068.2020.9189328 ◽

2020 ◽

Author(s):

Hongtao Liang ◽

Ning Qiang

Keyword(s):

Cooperative Control ◽

Interaction Mechanism ◽

Distributed Cooperative Control

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Process Description of an Unconventional Biofilm Formation by Bacterial Cells Autoagglutinating Through Sticky, Long, and Peritrichate Nanofibers

10.26434/chemrxiv.10001924.v1 ◽

2019 ◽

Author(s):

Yoshihide Furuichi ◽

Shogo Yoshimoto ◽

Tomohiro Inaba ◽

Nobuhiko Nomura ◽

Katsutoshi Hori

Keyword(s):

Formation Process ◽

Biofilm Formation ◽

Extracellular Polymeric Substances ◽

Waste Treatment ◽

Large Cell ◽

Dlvo Theory ◽

Bacterial Cells ◽

Chemical Production ◽

Discontinuous Surface ◽

Cell Cell

Biofilms are used in environmental biotechnologies including waste treatment and environmentally friendly chemical production. Understanding the mechanisms of biofilm formation is essential to control microbial behavior and improve environmental biotechnologies. Acinetobacter sp. Tol 5 autoagglutinate through the interaction of the long, peritrichate nanofiber protein AtaA, a trimeric autotransporter adhesin. Using AtaA, without cell growth or the production of extracellular polymeric substances, Tol 5 cells quickly form an unconventional biofilm. In this study, we investigated the formation process of this unconventional biofilm, which started with cell–cell interactions, proceeded to cell clumping, and led to the formation of large cell aggregates. The cell–cell interaction was described by DLVO theory based on a new concept, which considers two independent interactions between two cell bodies and between two AtaA fiber tips forming a virtual discontinuous surface. If cell bodies cannot collide owing to an energy barrier at low ionic strengths but approach within the interactive distance of AtaA fibers, cells can agglutinate through their contact. Cell clumping proceeds following the cluster–cluster aggregation model, and an unconventional biofilm containing void spaces and a fractal nature develops. Understanding its formation process would extend the utilization of various types of biofilms, enhancing environmental biotechnologies.

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Filtration resistance induced by ammonia oxidizers accumulating on the rotating membrane disk

Water Science & Technology ◽

10.2166/wst.1998.0690 ◽

1998 ◽

Vol 38 (4-5) ◽

pp. 443-452

Author(s):

Katsuki Kimura ◽

Yoshimasa Watanabe ◽

Naoki Ohkuma

Keyword(s):

Membrane Filtration ◽

Extracellular Polymeric Substances ◽

Drinking Water Treatment ◽

Treatment Method ◽

Operating Conditions ◽

Transmembrane Pressure ◽

Ammonia Oxidizers ◽

Filtration Resistance ◽

Rotating Membrane Disk ◽

Membrane Disk

Membrane filtration and oxidation of ammonia were simultaneously performed by using a rotating membrane disk module. Nitrification performance, composition of the accumulated cakes on the membrane and the filtration resistances were investigated under five different operating conditions. The filtration resistance due to the accumulated cake on the membrane was found to be dominant in this treatment method, compared to the resistance due to the micropore plugging or irreversible adherence. The cake consisted mainly of iron, humic substances and bacteria. The possibility that extracellular polymeric substances were related to the cake resistance was also shown. The composition of the cake depended on the length and the condition of operation. Accumulation of ammonia oxidizers caused by oxidation of low concentrations of ammonia (less than 1 mg/l) did not increase transmembrane pressure significantly. Therefore, the application of this treatment method for drinking water treatment is feasible. Filtration resistance due to the micropore plugging or irreversible adherence to the membrane was caused by organic substances.

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Antibiotics Application Strategies to Control Biofilm Formation in Pathogenic Bacteria

Current Pharmaceutical Biotechnology ◽

10.2174/1389201020666191112155905 ◽

2020 ◽

Vol 21 (4) ◽

pp. 270-286 ◽

Cited By ~ 2

Author(s):

Fazlurrahman Khan ◽

Dung T.N. Pham ◽

Sandra F. Oloketuyi ◽

Young-Mog Kim

Keyword(s):

Biofilm Formation ◽

Pathogenic Bacteria ◽

Extracellular Polymeric Substances ◽

Quorum Quenching ◽

Resistance Mechanisms ◽

Bacterial Biofilm ◽

Bacterial Cells ◽

High Concentration ◽

Biofilm Inhibition ◽

Abiotic Surfaces

Background: The establishment of a biofilm by most pathogenic bacteria has been known as one of the resistance mechanisms against antibiotics. A biofilm is a structural component where the bacterial community adheres to the biotic or abiotic surfaces by the help of Extracellular Polymeric Substances (EPS) produced by bacterial cells. The biofilm matrix possesses the ability to resist several adverse environmental factors, including the effect of antibiotics. Therefore, the resistance of bacterial biofilm-forming cells could be increased up to 1000 times than the planktonic cells, hence requiring a significantly high concentration of antibiotics for treatment. Methods: Up to the present, several methodologies employing antibiotics as an anti-biofilm, antivirulence or quorum quenching agent have been developed for biofilm inhibition and eradication of a pre-formed mature biofilm. Results: Among the anti-biofilm strategies being tested, the sub-minimal inhibitory concentration of several antibiotics either alone or in combination has been shown to inhibit biofilm formation and down-regulate the production of virulence factors. The combinatorial strategies include (1) combination of multiple antibiotics, (2) combination of antibiotics with non-antibiotic agents and (3) loading of antibiotics onto a carrier. Conclusion: The present review paper describes the role of several antibiotics as biofilm inhibitors and also the alternative strategies adopted for applications in eradicating and inhibiting the formation of biofilm by pathogenic bacteria.

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Cytotoxic Activity and DNA Binding Property of New Aminopyrimidine Derivatives

Letters in Drug Design & Discovery ◽

10.2174/1570180816666190712102119 ◽

2020 ◽

Vol 17 (5) ◽

pp. 640-654

Author(s):

Hamidreza Akrami ◽

Bibi Fatemeh Mirjalili ◽

Omidreza Firuzi ◽

Azadeh Hekmat ◽

Ali Akbar Saboury ◽

...

Keyword(s):

Cell Lines ◽

Anticancer Agents ◽

Lymphoblastic Leukemia ◽

Cd Spectroscopy ◽

Myelogenous Leukemia ◽

Breast Adenocarcinoma ◽

Binding Property ◽

Anticancer Compounds ◽

Calf Thymus ◽

Dna Binding Property

Background: Chromene and anilinopyrimidine heterocyclics are attractive anticancer compounds that have inspired many researchers to design novel derivatives bearing improved anticancer activity. Methods: A series of pyrimidine-fused benzo[f]chromene derivatives 6a-x were synthesized as anticancer hybrids of 1H-benzo[f]chromenes and anilinopyrimidines. The inhibitory activity of the synthesized compounds 6a-x against cell viability of human chronic myelogenous leukemia (K562), human acute lymphoblastic leukemia (MOLT-4) and human breast adenocarcinoma (MCF-7) cell lines was evaluated using MTT assay. The interaction of the most promising compound with calf-thymus DNA was also studied using spectrometric titrations and Circular Dichroism (CD) spectroscopy. Results: Most compounds showed promising activity against tested cell lines. Among them, 2,4- dimethoxyanilino derivative 6g exhibited the best profile of activity against tested cell lines (IC50s = 1.6-6.1 μM) with no toxicity against NIH3T3 normal cell (IC50 >200 μM). The spectrometric studies exhibited that compound 6g binds to DNA strongly and may change DNA conformation significantly, presumably via a groove binding mechanism. Conclusion: The results of this study suggest that the prototype compound 6g can be considered as a novel lead compound for the design and discovery of novel anticancer agents.

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