Vancomycin recognition and induced-aggregation of the Au nanoparticles through freeze-thaw for foodborne pathogen Staphylococcus aureus detection

2021 ◽  
pp. 339253
Author(s):  
Ruimeng Sun ◽  
Hangjin Zou ◽  
Yang Zhang ◽  
Xinming Zhang ◽  
Lixia Chen ◽  
...  
Pharmaceutics ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 52
Author(s):  
Atanu Naskar ◽  
Sohee Lee ◽  
Kwang-sun Kim

Antibiotic therapy is the gold standard for bacterial infections treatment. However, the rapid increase in multidrug-resistant (MDR) bacterial infections and its recent use for secondary bacterial infections in many COVID-19 patients has considerably weakened its treatment efficacy. These shortcomings motivated researchers to develop new antibacterial materials, such as nanoparticle-based antibacterial platform with the ability to increase the chances of killing MDR strains and prevent their drug resistance. Herein, we report a new black phosphorus (BP)-based non-damaging near-infrared light-responsive platform conjugated with ZnO and Au nanoparticles as a synergistic antibacterial agent against Staphylococcus aureus species. First, BP nanosheets containing Au nanoparticles were assembled in situ with the ZnO nanoparticles prepared by a low-temperature solution synthesis method. Subsequently, the antibacterial activities of the resulting Au–ZnO–BP nanocomposite against the non-resistant, methicillin-resistant, and erythromycin-resistant S. aureus species were determined, after its photothermal efficacy was assessed. The synthesized nanocomposite exhibited excellent anti-S. aureus activity and good photothermal characteristics. The non-resistant S. aureus species did not produce drug-resistant bacteria after the treatment of multiple consecutive passages under the pressure of the proposed nanoantibiotic, but rapidly developed resistance to erythromycin. This work clearly demonstrates the excellent photothermal antibacterial properties of Au–ZnO–BP nanocomposite against the MDR S. aureus species.


2002 ◽  
Vol 65 (6) ◽  
pp. 1008-1015 ◽  
Author(s):  
ODDUR VILHELMSSON ◽  
KAREN J. MILLER

The effects of different humectants (sodium chloride, sucrose, and glycerol) on the growth of and compatible solute (glycine betaine, proline, and carnitine) uptake by the osmotolerant foodborne pathogen Staphylococcus aureus were investigated. While growth in the presence of the impermeant humectants sodium chloride and sucrose induced the accumulation of proline and glycine betaine by cells, growth in the presence of the permeant humectant glycerol did not. When compatible solutes were omitted from low-water-activity media, growth was very poor in the presence of impermeant humectants. In contrast, the addition of compatible solutes had essentially no effect on growth when cells were grown in low-water-activity media containing glycerol as the humectant. Carnitine was found to accumulate to high intracellular levels in osmotically stressed cells when proline and glycine betaine were absent, making it a potentially important compatible solute for this organism.


2020 ◽  
Vol 21 (15) ◽  
pp. 5552
Author(s):  
Liyi Chen ◽  
Yajun Sun ◽  
Yun Liu ◽  
Yongdong Zou ◽  
Jianzi Huang ◽  
...  

Late embryogenesis abundant (LEA) group 1 (LEA_1) proteins are intrinsically disordered proteins (IDPs) that play important roles in protecting plants from abiotic stress. Their protective function, at a molecular level, has not yet been fully elucidated, but several studies suggest their involvement in membrane stabilization under stress conditions. In this paper, the soybean LEA_1 protein PM1 and its truncated forms (PM1-N: N-terminal half; PM1-C: C-terminal half) were tested for the ability to protect liposomes against damage induced by freeze-thaw stress. Turbidity measurement and light microscopy showed that full-length PM1 and PM1-N, but not PM1-C, can prevent freeze-thaw-induced aggregation of POPC (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine) liposomes and native thylakoid membranes, isolated from spinach leaves (Spinacia oleracea). Particle size distribution analysis by dynamic light scattering (DLS) further confirmed that PM1 and PM1-N can prevent liposome aggregation during freeze-thaw. Furthermore, PM1 or PM1-N could significantly inhibit membrane fusion of liposomes, but not reduce the leakage of their contents following freezing stress. The results of proteolytic digestion and circular dichroism experiments suggest that PM1 and PM1-N proteins bind mainly on the surface of the POPC liposome. We propose that, through its N-terminal region, PM1 functions as a membrane-stabilizing protein during abiotic stress, and might inhibit membrane fusion and aggregation of vesicles or other endomembrane structures within the plant cell.


Langmuir ◽  
2000 ◽  
Vol 16 (23) ◽  
pp. 8789-8795 ◽  
Author(s):  
Andrew N. Shipway ◽  
Michal Lahav ◽  
Rachel Gabai ◽  
Itamar Willner

2021 ◽  
pp. 152-160
Author(s):  
Adnan Shahid ◽  
Afsheen Rafiq

Staphylococcus aureus (S. aureus) is gram positive, catalase positive cocci which belongs to the family of Staphylococcaceae and is long known as clinical and foodborne pathogen. The emergence of multidrug resistance strain of S. aureus which is methicillin resistant S. aureus (MRSA) challenges the health care system because it can cause wide variety of hospital and community acquired skin and soft tissue infections which are difficult to treat. The virulence of S. aureus is because of different factors which includes toxins, enzymes and superantigens. S. aureus produce variety of exotoxins, enterotoxins and exfoliative toxins which contributes to the virulence of S. aureus. Hemolysin toxins produce by S. aureus strains are associated with different skin and soft tissue infections (SSTIs) and can cause the lysis of RBCs. Hemolysins are regulated by accessory gene regulator (agr) and is required for the enhanced expression of virulence factors secreted by S. aureus. Hemolysins have leucolytic activity and can help in iron scavenging from host. The most important toxin is alpha hemolysin which can induce the apoptosis and cause the lysis of epithelial cells, erythrocytes and keratinocytes. Human immune cells are affected by beta hemolysin and gamma hemolysin is a biocomponent toxin. Delta hemolysin is low molecular weight exotoxin which belongs to the class of phenol soluble modulins. Keywords: MRSA, Exotoxins, Hemolysins, SSTIs


2019 ◽  
Vol 476 (7) ◽  
pp. 1121-1135 ◽  
Author(s):  
Fanny Yuen ◽  
Matthew Watson ◽  
Robert Barker ◽  
Isabelle Grillo ◽  
Richard K. Heenan ◽  
...  

Abstract Late embryogenesis abundant (LEA) proteins comprise a diverse family whose members play a key role in abiotic stress tolerance. As intrinsically disordered proteins, LEA proteins are highly hydrophilic and inherently stress tolerant. They have been shown to stabilise multiple client proteins under a variety of stresses, but current hypotheses do not fully explain how such broad range stabilisation is achieved. Here, using neutron reflection and surface tension experiments, we examine in detail the mechanism by which model LEA proteins, AavLEA1 and ERD10, protect the enzyme citrate synthase (CS) from aggregation during freeze–thaw. We find that a major contributing factor to CS aggregation is the formation of air bubbles during the freeze–thaw process. This greatly increases the air–water interfacial area, which is known to be detrimental to folded protein stability. Both model LEA proteins preferentially adsorb to this interface and compete with CS, thereby reducing surface-induced aggregation. This novel surface activity provides a general mechanism by which diverse members of the LEA protein family might function to provide aggregation protection that is not specific to the client protein.


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