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Representative (from triplicate experiment) matrix-assisted laser desorption/ionization–time-of-flight mass spectrometry (MALDI-TOF MS) spectra of E. coli in MH medium obtained using the “DIRECT” and “EXTRACTION” procedure.
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Escherichia coli and salivary Klebsiella oxytoca and Staphylococcus saccharolyticus were subjected to different concentrations of silver nanoparticles (AgNPs), namely: 12.5, 50, and 100 µg mL-1. Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) spectra were acquired after specified periods: 0, 1, 4, and 12...
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Citations
... 48 This attraction may lead to enhanced antibacterial activity against Gram-negative bacteria. [48][49][50][51] Furthermore, antibiotic-resistant bacteria pose a significant threat to public health worldwide. Biogenic nanoparticles offer a promising alternative to conventional antibiotics for combating resistant strains. ...
The application of nanotherapeutics is being considered as one of the most sought-after strategies to combat the threat posed by drug resistant bacteria. One promising type of nanotherapeutic is biogenic silver nanoparticles (bAgNPs) generated through exploiting the reducing potential of plant extracts. Herein, bAgNPs were synthesized at pH 7.4 (bAgNPs) and pH 10 (bAgNPs@pH) through green chemistry approaches using an extract of Phyllanthus emblica fruit as a source of reducing agent. The physicochemical properties, antibacterial potential, and biocompatibility of the as-synthesized bAgNPs were determined. The average size of bAgNPs and bAgNPs@pH was 15.3 and 20.1 nm, respectively, and both types of nanoparticles were negatively charged (i.e., ∼−25 mV). The as-synthesized bAgNPs exhibited excellent antibacterial activity against different bacterial strains such as Bacillus subtilis RBW, Escherichia coli DH5a, Salmonella typhi, Hafnia alvei, enteropathogenic E. coli, Vibrio cholerae, and Staphylococcus aureus. The most effective antibacterial activity of bAgNPs and bAgNPs@pH was observed against Hafnia alvei, a Gram-negative bacterium, with a zone of inhibition (ZOI) of ∼24 and 26 mm in diameter, respectively. The nanoparticles exhibited antibacterial activity through damaging the bacterial cell wall, oxidizing the membrane fatty acids, and interacting with cellular macromolecules to bring about bacterial death. Furthermore, bAgNPs showed excellent hemocompatibility against human red blood cells, and there was no significant toxicity observed in rat serum ALT, AST, γ-GT, and creatinine levels. Thus, bAgNPs synthesized using Phyllanthus emblica fruit extract hold great promise as nanotherapeutics to combat a broad spectrum of pathogenic bacteria. Future directions may involve further exploration of the potential applications of biogenic silver nanoparticles in clinical settings, including studies on long-term efficacy, extensive in vivo toxicity profiles, and scalable production methods for clinical use.
... 65 On the other hand, AgNPs, as vital components of AgLTF complex, act against bacteria in the following manner: (i) damage of the membrane and alteration of transport activity, (ii) inhibition of cell wall formation, (iii) modulation of the cellular signal system and induction of oxidative stress, (iv) prevention of replication of DNA, cell division and respiratory chain processes, and (v) inhibition of cell growth caused by dephosphorylation of protein substrates. 16 Our previous studies have presented metabolic changes in bacteria upon treatment with silver ions and AgNPs with a focus on alternations in volatile profiles and protein signatures and depicted bacterial pathways supposed to be involved in the formation of metabolites. 14, 16 2.5. ...
... 16 Our previous studies have presented metabolic changes in bacteria upon treatment with silver ions and AgNPs with a focus on alternations in volatile profiles and protein signatures and depicted bacterial pathways supposed to be involved in the formation of metabolites. 14, 16 2.5. Protein and Metabolic Profiles Assessed using MALDI−TOF MS. ...
A diverse silver−lactoferrin (AgLTF) complex, comprising silver ions (Ag +) and silver nanoparticles, displayed a synergistic antibacterial effect while being almost five times more lethal than LTF alone. Gas chromatography−mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry�in linear (LP) and reflectron (RP) positive modes�were used to comprehensively analyze metabolites and proteins profiles of bacteria (Staphylococcus aureus (SA), Pseudomonas aeruginosa (PA) and Enterococcus faecalis (EF)) treated using AgLTF complex versus exclusively Ag +. Although both agents resulted in similar metabolic shifts in bacteria, AgLTF significantly triggered the production of sulfides (related to bacterial stress resistance), ethanol, 2-butanol (indicating exhaustion of cell respiration), decanoic acid, and nonane (suggesting ongoing oxidative stress). Keto acids formation and fermentation pathways were enhanced by AgLTF and suppressed by Ag +. Furthermore, AgLTF appears to interact with proteins fraction of bacteria in a concentration-dependent manner. EF molecular profiles showed less changes between treated and untreated bacteria. On the other hand, SA and PA proteins and metabolic patterns were the most differentiated from untreated bacteria. In conclusion, our study may provide valuable insights regarding the molecular mechanisms involved in AgLTF antimicrobial action.
... Therefore, NPs are more easily absorbed by Gram-negative bacteria, followed by the transfer of reactive oxygen species (ROS) to bacteria through diffusion. Moreover, the greater effect of fabricated NPs on Gram-negative bacteria can be ascribed to the existence of a more substantial peptidoglycan layer in Gram-positive bacteria (Devanesan and AlSalhi, 2021;Monedeiro et al., 2019;Sharifi-Rad et al., 2020;Zare-Bidaki et al., 2023). Previous investigations have demonstrated that the antibacterial potency of green AgNPs is determined by morphology, surface chemistry, size, existence charge on their surface, surface coating, and nature of particles (Bekele and Alamnie, 2022;Zare-Bidaki et al., 2023). ...
... This is because AgNPs possess a positive charge that could attach better and penetrate through the cell wall membrane. 45 Furthermore, the binding of AgNPs to the bacterial cell wall proteins causes a reduction in the membrane's permeability and leakage of intracellular components, which nally leads to bacterial death. 46 In addition to the cell membrane damage, nanoparticles alter the cell function by interacting with amino acids and enzymes, causing the generation of reactive oxygen species (ROS) and misfolding of bacterial DNA. ...
In this study, Retama monosperma extract (RME) was used for the green synthesis of silver nanoparticles (RME-AgNPs). RME's phenolic profile was identified by liquid chromatography coupled to mass spectroscopy (LC-ESI/MS/MS) technique. A tentative identification of 21 phenolic metabolites from the extract was performed. The produced RME-AgNPs showed UV absorbance at 443 nm. FTIR spectroscopy confirmed the presence of RME functional groups. In addition, XRD analysis confirmed the crystallography of RME-AgNPs via exhibiting peaks with 2θ values at 38.34°, 44.29°, and 64.65°. RME-AgNPs were spherical with particle sizes ranging from 9.87 to 21.16 nm, as determined by SEM and HR-TEM techniques. The zeta potential determined the particle's charge value as −15.25 mv. RME-AgNPs exhibited significantly higher antibacterial activity against Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Serratia marcescens, and Klebsiella pneumoniae) and Gram-positive bacteria (Bacillus subtilis and Staphylococcus aureus) compared to RME. Moreover, the SEM images of green-synthesized nanoparticles revealed severe damage and deformation in the bacterial cell wall of the different strains subjected to the current investigation. The bioinformatics study identified 266 targets, among which only 41 targets were associated with bacterial infections. The PI3K-Akt and Relaxin signaling pathways were the top KEGG signaling pathways. Molecular docking was also performed for the 21 identified compounds at the TNF-α active site; kaempferol-3-O-robinoside-7-O-rhamnoside had a higher binding energy (−6.8084). The findings of this study warrant the use of green-synthesized AgNPs from Retama monosperma as potential antibacterial agents.
... 14) on gram-negative bacteria with MIC about 31.25 lg/ml, and Streptococcus mitis and Enterococcus faecalis showed the lower effect on grampositive bacteria with MIC around 250 lg/ml. The difference between gram-positive and gram-negative bacteria is the existence of a thicker peptidoglycan layer in gram-positive cell wall and maybe the main reason influencing the more effect of AgNPs@PCS on gram-negative bacteria (Monedeiro et al., 2019). Furthermore, gram-negative bacteria have a lipopolysaccharide layer that has a positive charge, but AgNPs@PCS has a negative surface charge, which causes more accumulation of nanoparticles on the surface of gram-negative bacteria (Sharifi-Rad et al., 2020). ...
Today, wound healing is an important clinical problem that is often affected by microbial infection and not paying attention to this problem can cause irreparable damage to people. Biosynthesis of metal nanoparticles (NPs) has created a huge revolution in the field of nanomedicine due to their non-toxic, biocompatible, and stable characteristics. For this purpose, in this study, Petroselinum crispum seed extract (PCS) was applied to preparation of silver nanoparticles (AgNPs@PCS). The optimization of the silver nanoparticle synthesis involved adjusting the concentration of the silver salt, as well as the time and temperature parameters. After identifying the fabricated nanoparticles by FESEM, XRD, FT-IR, UV–Vis, TEM and EDS, their biological activity (like antibacterial, antifungal, antioxidant, anticancer, and wound treatment) was determined. The green synthesis of AgNPs was confirmed by several characteristics, including the surface plasmon response with a peak around 420 nm, the presence of both regular and heterogeneous sizes in the sample, and the observed color change from a clear solution to a brown color. The antimicrobial properties of the biofabricated AgNPs were investigated against fungal and various bacteria. The anticancer property of AgNPs@PCS was demonstrated by an IC50 value of 200 µg/ml after a 24-hour exposure on the MCF-7 cell line. Also, a dose-dependent antioxidant performance of AgNPs was found against the DPPH free radical. Histopathological evaluations of AgNPs@PCS ointment illustrated significant decrease in inflammatory cells. The results showed that vaseline ointment containing AgNPs@PCS prevented inflammation in the wound area and increased the number of fibroblast cells, which led to accelerated wound healing. Furthermore, in-vivo investigation showed the higher percentage of wound closure on days 7 and 14 was than the control group (Vaseline). Interestingly, the wound was completely closed after 21 days. Thus, we concluded that Petroselinum crispum-mediated silver nanoparticles show potential biological activity which can be used as nano-drug in clinical treatment.
... The synthesized NiO NPs exhibited a higher inhibition against Shigella flexneri followed by Proteus vulgaris, E. coli, S. typhi, Streptococcus epidermis, Pseudomonas aeruginosa, and Klebsiella pneumonia, methicillin-resistant Staphylococcus aureus, and Bacillus cereus while the MEPM showed significant inhibition in a decreasing order against S. typhi, Klebsiella pneumonia, Pseudomonas aeruginosa, Bacillus cereus, Streptococcus epidermis, methicillin-resistant Staphylococcus aureus, Proteus vulgaris, Shigella flexneri, and E. coli. However, the NiO NPs exhibited higher activity in Gram-negative bacteria due to their positive relative charge that resulted in the penetration of the cell surface via attachment to the negatively charged components (liposacccharides) [47]. On entering the cells into the bacteria cytoplasm, the NiO NPs, might intermingle with macromolecules such as DNA, RNA, enzymes, proteins, and ribosomes, causing deterioration and eventual release of the cellular contents resulting in damage to the intracellular structures and finally leading to bacterial death [48]. ...
... NiO-NPs at 500 μg/mL against the Gram-negative bacterial strains (E. coli, S. typhi, Shigella flexneri, Pseudomonas aeruginosa, Proteus vulgaris, and Klebsiella pneumonia) and the Gram-positive bacterial strains (Bacillus cereus, Staphylococcus aureus, and Streptococcus epidermis) using [47]. On entering the cells into the bacteria cytoplasm, the NiO-NPs, might intermingle with macromolecules such as DNA, RNA, enzymes, proteins, and ribosomes, causing deterioration and eventual release of the cellular contents resulting in damage to the intracellular structures and finally leading to bacterial death [48]. ...
... Out of the 35 compounds that significantly decreased in the breath samples after tooth brushing, 33 have been connected in earlier reports to the oral bacteria [3,[4][5][6][7][8][25][26][27]. The two exceptions are isoprene and vinyl methacrylate. ...
... Summary of the compounds that significantly decreased in the breath of healthy individuals after tooth brushing and that have also been connected to different oral niches in vitro. In total, 33 compounds were found for cariogenic bacteria (Streptococcus mutans, Lactobacillus salivarius, Propionibacterium acidifaciens) [6], salivary bacteria (Klebsiella oxytoca, Staphylococcus saccharolyticus) [7,25] and saliva headspace [8,26], tongue scrape [5,27], and subgingival anaerobes (P. gingivalis, Treponema denticola, P. intermedia, P. nigrescens, T. forsythia) [3,5]. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 A c c e p t e d M a n u s c r i p t 9 ...
... For example, several sulfur compounds previously proven to cause morning breath and halitosis [9][10][11][12][13][14][15][16][17][18], were found in increased amounts from our mixed breath samples before tooth brushing. Also, 33 of the 35 compounds that significantly decreased in our study after tooth brushing have been connected to oral bacteria in literature [3,[4][5][6][7][8][25][26][27]. In our opinion, these findings prove that the mixed breath samples used in this study represent the morning breath sufficiently well. ...
We have measured the composition of volatile organic compounds (VOCs) in the morning breath of 30 healthy individuals before and after tooth brushing. The concentrations of VOCs in the breath samples were measured with proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) and further identification was performed with a combination of solid phase microextraction (SPME) and offline gas chromatography–mass spectrometry (GC-MS). We hypothesize that compounds, whose concentrations significantly decreased in the breath after tooth brushing are largely of microbial origin. In this study, we found 35 such VOCs. Out of these, 33 have been previously connected to different oral niches, such as salivary and subgingival bacteria. We also compared the concentrations of the 35 VOCs found in increased amounts in the morning breath to their respective odor thresholds to evaluate their ability to cause odor. Compounds that could contribute to the breath odor include many volatile sulfur compounds, such as methanethiol, hydrogen sulfide, dimethyl sulfide, and 2-methyl-1-propanethiol, but also other VOCs, such as acetic acid, butyric acid, valeric acid, acetaldehyde, octanal, phenol, indole, ammonia, isoprene, and methyl methacrylate.
... Ong et al. [15] refined the chitosan dressing by combining a coagulant (polyphosphate) and Ag nanoparticles (NPs) to achieve hemostatic and antimicrobial effects. However, Ag NPs are cytotoxic [16][17][18] i.e. they cause cell membrane damage [19], DNA damage [20], oxidative stress [21], and the formation of reactive oxygen species (ROS) [22]. Staphylococcus aureus (S. aureus) is the most common type of bacterium that causes skin infection [23,24]. ...
Prevention of bacterial infection and reduction of haemorrhage, the primary challenges posed by pre-hospital trauma, are essential steps in prolonging the patient’s life until they have been transported to a trauma centre. Extracellular matrix hydrogel is a promising biocompatible material for accelerating wound closure. However, due to the lack of antibacterial properties, this hydrogel is difficult to be applied to acute contaminated wounds. This study formulates an injectable dermal extracellular matrix hydrogel (porcine acellular dermal matrix (ADM)) as a scaffold for skin defect repair. The hydrogel combines vancomycin, an anti-microbial agent for inducing haemostasis, expediting anti-microbial activity, and promoting tissue repair. The hydrogel possesses a porous structure beneficial for the adsorption of vancomycin. The anti-microbial agent can be timely released from the hydrogel within an hour, which is less than the time taken by bacteria to infest an injury, with a cumulative release rate of approximately 80%, and thus enables a relatively fast bactericidal effect. The cytotoxicity investigation demonstrates the biocompatibility of the ADM hydrogel. Dynamic coagulation experiments reveal accelerated blood coagulation by the hydrogel. In vivo anti-bacterial and haemostatic experiments on a rat model indicate the healing of infected tissue and effective control of haemorrhaging by the hydrogel. Therefore, the vancomycin-loaded ADM hydrogel will be a viable biomaterial for controlling haemorrhage and preventing bacterial infections in trauma patients.
... In the present study it was observed that the approach employing extraction was better for differentiation of bacteria with MALDI-TOF MS, which confirmed previous findings [36]. Better differentiation between the species in MH medium was achieved using "EXTRACTION" method when compared to "DIRECT" protocol: 5 ion clusters were obtained instead of only 3 ( Fig. 4b and d). ...
Culture medium composition influences the quality of bacterial protein profiles obtained using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The study aim was to investigate the influence of three liquid media that differed by carbon source abundance on the differentiation capability of computationally processed mass spectrum (MS) profiles of thirteen human-derived bacteria in positive linear and reflectron (RP) ionization modes. Direct ("intact cell") and sample extraction protocols were also compared. Unsupervised methods (principal component analysis and hierarchical cluster analysis) allowed observing profile distribution modulated according to the used medium. Optical density results and data analysis approaches showed that Mueller Hinton Broth medium was the most suitable considering both adequate bacterial growth and acquisition of bacteria-specific MS profiles. As it enabled better differentiation among species, extraction was superior to direct ("intact cell") method. Four machine learning algorithms were tested, aiming at simultaneous classification of bacteria. Random forest model presented the best performance, providing 100% accuracy in multiclass prediction. RP mode analysis provided more diverse MS profiles, displaying also a potential to be used for identification purposes. Additionally, canonical correlation analysis showed that linear and RP modes showed correlation, suggesting that linear mode profiles may be reflected on RP MS patterns.
