Light-induced reduction of silver ions to silver nanoparticles in aquatic environments by microbial extracellular polymeric substances (EPS)

Zhang, Xin; Yang, Cheng-Ao; Yu, Han‐Qing; Sheng, Guo‐Ping

doi:10.1016/j.watres.2016.10.004

Cited by 107 publications

(46 citation statements)

References 54 publications

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“…Effect of FNR or RcsDB inactivation on extracytoplasmic polysaccharides (mainly containing K capsules and colanic acids) biosynthesis in serum under low oxygen tension after 8h incubation. The absorbance at 520nm was measured to quantify the extractants of indicated strains (Cheng et al, 2010;Zhang et al, 2016). Statistical significance analysis was performed using a one-way ANOVA (**P < 0.01, *P < 0.05).…”

Section: Discussionmentioning

confidence: 99%

“…Bacterial capsules (mainly containing K capsules and colanic acids) were extracted using the previously described method with minor modifications (Blumenkrantz and Asboe-Hansen, 1973;Cheng et al, 2010;Zhang et al, 2016). Briefly, 800 µl eight-hours grown bacteria in low oxygen serum was mixed with 100 µl of 1% Zwittergent 3-14 (Sigma-Aldrich, St. Louis, MO, USA) in 100mM citric acid (pH 2.0) and then incubated at 50°C for 20 min.…”

Section: Extraction and Quantification Of Extracytoplasmic Polysacchamentioning

confidence: 99%

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Extraintestinal pathogenic Escherichia coli increase extracytoplasmic polysaccharide biosynthesis for serum resistance in response to bloodstream signals

Jiang

et al. 2018

Molecular Microbiology

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Extraintestinal pathogenic Escherichia coli (ExPEC) is one of the leading causes of bloodstream infections. Characteristically, these organisms exhibit strong resistance to the bactericidal action of host serum. Although numerous serum resistance factors in ExPEC have been identified, their regulatory mechanisms during in vivo infection remain largely unknown. Here, RNA sequencing analyses together with quantitative reverse-transcription PCR revealed that ExPEC genes involved in the biosynthesis of extracytoplasmic polysaccharides (ECPs) including K-capsule, lipopolysaccharide (LPS), colanic acid, peptidoglycan and Yjb exopolysaccharides were significantly upregulated in response to serum under low oxygen conditions and during bloodstream infection. The oxygen sensor FNR directly activated the expression of K-capsule and colanic acid and also indirectly modulated the expression of colanic acid, Yjb exopolysaccharides and peptidoglycan via the known Rcs regulatory system. The global regulator Fur directly or indirectly repressed the expression ofECP biosynthesis genes in iron replete media, whereas the low iron conditions in the bloodstream could relieve Fur repression. Using in vitro and animal models, FNR, Fur and the Rcs system were confirmed as contributing to ExPEC ECP production, serum resistance and virulence. Altogether, these findings indicated that the global regulators FNR andFur and the signaling transduction system Rcs coordinately regulated the expression of ECP biosynthesis genes leading to increased ExPEC serum resistance in response to low oxygen and low iron levels in the bloodstream.

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Section: Discussionmentioning

confidence: 99%

Section: Extraction and Quantification Of Extracytoplasmic Polysacchamentioning

confidence: 99%

Extraintestinal pathogenic Escherichia coli increase extracytoplasmic polysaccharide biosynthesis for serum resistance in response to bloodstream signals

Jiang

et al. 2018

Molecular Microbiology

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“…The former can be done by using the cell biomass, where the reducing agents are secreted by the cells and the nanoparticles formed might be attached to the bacterial wall (which can possibly extend the purification process). In contrast, using a bacterial supernatant/cell-free extract has the advantage of facilitating the downstream process and purification procedures by utilizing a sterile biomolecule-rich mixture to synthesize the nanoparticles, often with the aid of microwave [ 83 ] or light irradiation [ 84 ]. Conversely, the intracellular AgNPs synthesis takes place inside the cell, often in the periplasmic space [ 85 ].…”

Section: Biogenic Agnps As a Weapon Against Multidrug-resistant Bamentioning

confidence: 99%

Biogenic Nanosilver against Multidrug-Resistant Bacteria (MDRB)

et al. 2018

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Multidrug-resistant bacteria (MDRB) are extremely dangerous and bring a serious threat to health care systems as they can survive an attack from almost any drug. The bacteria’s adaptive way of living with the use of antimicrobials and antibiotics caused them to modify and prevail in hostile conditions by creating resistance to known antibiotics or their combinations. The emergence of nanomaterials as new antimicrobials introduces a new paradigm for antibiotic use in various fields. For example, silver nanoparticles (AgNPs) are the oldest nanomaterial used for bactericide and bacteriostatic purposes. However, for just a few decades these have been produced in a biogenic or bio-based fashion. This review brings the latest reports on biogenic AgNPs in the combat against MDRB. Some antimicrobial mechanisms and possible silver resistance traits acquired by bacteria are also presented. Hopefully, novel AgNPs-containing products might be designed against MDR bacterial infections.

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“…Zhang et al ., first described that light intensity could influence silver nanoparticle formation by biofilms of S . oneidensis 27 , but the effect of photo-induction including light intensity and wavelength in bio-fabrication of NPs has remained mysterious. To the best of our knowledge, the effect of light intensity on the biosynthesis of Au@NPs by S .…”

Section: Introductionmentioning

confidence: 99%

Mechanism study of photo-induced gold nanoparticles formation by Shewanella oneidensis MR-1

Huang

Chang

et al. 2019

Sci Rep

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Shewanella oneidensis MR-1, a bioelectricity generating bacterium, is broadly used in bioremediation, microbial fuel cell and dissimilatory reduction and recovery of precious metals. Herein, we report for the first time that photo induction as a trigger to stimulate gold nanoparticles (Au@NPs) formation by MR-1, with wavelength and light intensity as two key variables. Results indicated that sigmoidal model is the best fit for Au@NPs formation at various wavelengths (with R 2 > 0.97). Light intensity in terms of photosynthetic photon flux density (PPFD) critically influences the rate constant in the low-light intensity region (PPFD < 20), while wavelength controls the maximum rate constant in the high-light region (PPFD > 20). By deletion of Mtr pathway genes in MR-1, we proposed the mechanism for light induced Au@NP formation is the excitation effect of light on certain active groups and extracellular polymeric substances (EPS) on the cell surface. Also, the release of electrons from proteins and co-enzyme complexes enhance electron generation. To the best of our knowledge, this is the first-attempt to explore the effect of photo-induction on Au@NPs production by MR-1, which provides an alternative cost-effective and eco-friendly process in green chemical industry.

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Light-induced reduction of silver ions to silver nanoparticles in aquatic environments by microbial extracellular polymeric substances (EPS)

Cited by 107 publications

References 54 publications

Extraintestinal pathogenic Escherichia coli increase extracytoplasmic polysaccharide biosynthesis for serum resistance in response to bloodstream signals

Extraintestinal pathogenic Escherichia coli increase extracytoplasmic polysaccharide biosynthesis for serum resistance in response to bloodstream signals

Biogenic Nanosilver against Multidrug-Resistant Bacteria (MDRB)

Mechanism study of photo-induced gold nanoparticles formation by Shewanella oneidensis MR-1

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