scholarly journals Nano-curcumin Capped Au/ZnO Nanocomposite: A Promising Approach to Protect from Staphylococcus Aureus Infection through Inhibits Production of α-Hemolysin

Author(s):  
Majid Jabir ◽  
Majid Jabir ◽  
Taha M. Rashid ◽  
Uday M. Nayef ◽  
Duha A. Kadhim

Abstract Gold with Zinc Oxide nanoparticles (Au@ZnO NPs) were prepared by laser ablation then capped with Curcumin nanoparticles. The ability of Nano-curcumin-Au/ZnO nanocomposite as a promising antibacterial agent was tested against Staphylococcus aureus. Cur-Au@ZnO NPs were characterized by TEM, FTIR spectroscopy, and Uv-spectroum. TEM image of Au@ZnO NPs has grain size almost 27–38 nm and it increased after capped Nano-curcumin to 72–113 nm. Agar well diffusion method was used to evaluate the antibacterial activity of Cur-Au@ZnO against S.aureus. The activity of Cur-Au@ZnO NPs was determined via detection of (ROS) using (AO/EtBr) staining assay. The bacterial cytoplasmic membrane and nucleic acid were penetrated by tested nanoparticles, resulting in bacterial strain destruction. The results showed that Cur-Au@ZnO NPs as a novel DNA-mediated antibacterial agent. The Cur-Au@ZnO were observed to destroy the bacterial cells by permeating the bacterial nucleic acid and cytoplasmic membrane, resulting in the loss of cell-wall integrity, nucleic acid damage, and increased cell-wall permeability. Furthermore, in the present study we investigated the activity of Cur-Au@ZnO NPs against bacterial α-Hemolysin toxin. Western blot were used to measure the effect of Cur-Au@ZnO NPs on α-Hemolysin produced by S. aureus. The effectiveness of Cur-Au@ZnO NPs against human alveolar epithelial cell injury by α-Hemolysin was tested using live ⁄ dead staining. Also, we demonstrated the role of Cur-Au@ZnO NPs against S. aureus through histopathology examination in a mouse model. Taken together, Cur-Au@ZnO NPs is a potent inhibitor of α-hemolysin secreted by S. aureus. So, Cur-Au@ZnO NPs mediated inhibition of α-Hemolysin production may offer a new strategy in combating pathogen infections. The Cur-Au@ZnO could serve as a potential antibacterial agent in future for biomedical and pharmaceutical applications.

2019 ◽  
Vol 26 (10) ◽  
pp. 1950079 ◽  
Author(s):  
WALEED K. ABDUL KADHIM ◽  
UDAY M. NAYEF ◽  
MAJID S. JABIR

Magnetite (Fe3O4) nanoparticles (MPs) capped with polyethylene glycol (PEG) were prepared by a hydrothermal method, and their antibacterial activity was examined against Staphylococcus aureus, Escherichia coli and Psudomonas aeruginosa. The functionalized NPs were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), Fourier transform infrared (FTIR) spectroscopy, and Thermogravimetry (TG). The average size of the Fe3O4 was in the range 9–20[Formula: see text]nm, while the functionalized PEG–Fe3O4 had an average size of 5–15[Formula: see text]nm. The PEG–Fe3O4 exhibited superparamagnetism and high saturation magnetization at room temperature. The antibacterial activity of the Fe3O4 and PEG–Fe3O4 were evaluated against E. coli, S. aureus, and P. aeruginosa using the agar well diffusion method. The changes in the morphology of the studied bacterial species were observed via SEM, while the mode of action of the studied agents was determined via the detection of reactive oxygen species (ROS) using Acridine orange-ethidium bromide (AO/EtBr) staining method. The results showed that PEG-functionalized magnetic (Fe3O4) NPs as a novel DNA-mediated antibacterial agent. The PEG–Fe3O4 NPs were observed to destroy the bacterial cells by permeating the bacterial nucleic acid and cytoplasmic membrane, resulting in the loss of cell-wall integrity, nucleic acid damage, and increased cell-wall permeability. The PEG–Fe3O4 NPs could serve as a potential antibacterial agent in future biomedical and pharmaceutical applications.


Author(s):  
Kyoung- Sun Seo ◽  
Seong Woo Jin ◽  
Seongkyu Choi ◽  
Kyeong Won Yun

The antibacterial activity of three Cupressaceae plants (Thujaoccidentalis,ThujaorientalisandChamaecyparisobtusa) was tested against three bacteria using the agar diffusion method. The ether and ethylacetate fraction of crude methanol extract from the three plants showed potent antibacterial activity against the tested microorganisms. The result showed that Staphylococcus aureus revealed the most sensitivity among the tested bacteria. Thujaoccidentalisether fraction and Thujaorientalis hexane fraction exhibited the highest antibacterial activity against Staphylococcus aureus. E. coli was shown the highest MIC values compared to the other two tested bacteria, which indicates the lowest antibacterial activity against the bacterium. This study promises an interesting future for designing a potentially active antibacterial agent from the three Cupressaceae plants.


2020 ◽  
Vol 8 (12) ◽  
pp. 1991
Author(s):  
Alina Grigor’eva ◽  
Alevtina Bardasheva ◽  
Anastasiya Tupitsyna ◽  
Nariman Amirkhanov ◽  
Nina Tikunova ◽  
...  

Antimicrobial peptides, including synthetic ones, are becoming increasingly important as a promising tool to fight multidrug-resistant bacteria. We examined the effect of cationic peptides H2N-Arg9-Phe2-C(O)NH2 and H2N-(Lys-Phe-Phe)3-Lys-C(O)NH2 on Staphylococcus aureus, which remains one of the most harmful pathogens. Antiseptic chlorhexidine served as reference preparation. We studied viability of S. aureus and examined its ultrastructure under treatment with 100 µM of R9F2 or (KFF)3K peptides or chlorhexidine using transmission electron microscopy of ultrathin sections. Bacterial cells were sampled as kinetic series starting from 1 min up to 4 h of treatment with preparations. Both peptides caused clearly visible damage of bacteria cell membrane within 1 min. Incubation of S. aureus with R9F2 or (KFF)3K peptides led to cell wall thinning, loss of cytoplasm structure, formation of mesosome-derived multimembrane structures and “decorated fibers” derived from DNA chains. The effect of R9F2 peptides on S. aureus was more severe than the effect of (KFF)3K peptides. Chlorhexidine heavily damaged the bacteria cell wall, in particular in areas of septa formation, while cytoplasm kept its structure within the observation time. Our study showed that cell membrane damage is critical for S. aureus viability; however, we believe that cell wall disorders should also be taken into account when analyzing the effects of the mechanisms of action of antimicrobial peptides (AMPs).


2015 ◽  
Vol 2 (2) ◽  
pp. 190
Author(s):  
Yefrida ◽  
Farrah Aprilina ◽  
Indri Ticel Leone ◽  
Refilda

 ABSTRAK Antibacterial agent is a compound that prevent the growth and reproduction of bacteria. Antibacterial activity of liquid smoke is caused by acid and fenolic compound. In this research, we determined antibacterial activity of liquid smoke from stem sweet wood  and nut shell by using diffusion method. Both of liquid smoke have antibacterial activity to Staphylococcus aureus  Eschericia coli population. Their activity almost the same to chloramphenicol, but less than formalin. Keywords : antibacterial activity, liquid smoke, diffusion method    


2021 ◽  
Vol 17 (3) ◽  
pp. e1009468
Author(s):  
Joshua A. F. Sutton ◽  
Oliver T. Carnell ◽  
Lucia Lafage ◽  
Joe Gray ◽  
Jacob Biboy ◽  
...  

Peptidoglycan is the major structural component of the Staphylococcus aureus cell wall, in which it maintains cellular integrity, is the interface with the host, and its synthesis is targeted by some of the most crucial antibiotics developed. Despite this importance, and the wealth of data from in vitro studies, we do not understand the structure and dynamics of peptidoglycan during infection. In this study we have developed methods to harvest bacteria from an active infection in order to purify cell walls for biochemical analysis ex vivo. Isolated ex vivo bacterial cells are smaller than those actively growing in vitro, with thickened cell walls and reduced peptidoglycan crosslinking, similar to that of stationary phase cells. These features suggested a role for specific peptidoglycan homeostatic mechanisms in disease. As S. aureus penicillin binding protein 4 (PBP4) has reduced peptidoglycan crosslinking in vitro its role during infection was established. Loss of PBP4 resulted in an increased recovery of S. aureus from the livers of infected mice, which correlated with enhanced fitness within murine and human macrophages. Thicker cell walls correlate with reduced activity of peptidoglycan hydrolases. S. aureus has a family of 4 putative glucosaminidases, that are collectively crucial for growth. Loss of the major enzyme SagB, led to attenuation during murine infection and reduced survival in human macrophages. However, loss of the other three enzymes Atl, SagA and ScaH resulted in clustering dependent attenuation, in a zebrafish embryo, but not a murine, model of infection. A combination of pbp4 and sagB deficiencies resulted in a restoration of parental virulence. Our results, demonstrate the importance of appropriate cell wall structure and dynamics during pathogenesis, providing new insight to the mechanisms of disease.


Author(s):  
Sri Atun ◽  
Sri Handayani ◽  
Melia Aliffiana ◽  
Hajar Nur Afifah ◽  
Anna Rakhmawati

The antibacterial activity of three Cupressaceae plants (Thujaoccidentalis,ThujaorientalisandChamaecyparisobtusa) was tested against three bacteria using the agar diffusion method. The ether and ethylacetate fraction of crude methanol extract from the three plants showed potent antibacterial activity against the tested microorganisms. The result showed that Staphylococcus aureus revealed the most sensitivity among the tested bacteria. Thujaoccidentalisether fraction and Thujaorientalis hexane fraction exhibited the highest antibacterial activity against Staphylococcus aureus. E. coli was shown the highest MIC values compared to the other two tested bacteria, which indicates the lowest antibacterial activity against the bacterium. This study promises an interesting future for designing a potentially active antibacterial agent from the three Cupressaceae plants.


mBio ◽  
2018 ◽  
Vol 9 (6) ◽  
Author(s):  
Katja Schlatterer ◽  
Christian Beck ◽  
Dennis Hanzelmann ◽  
Marco Lebtig ◽  
Birgit Fehrenbacher ◽  
...  

ABSTRACT The innate immune system uses Toll-like receptor (TLR) 2 to detect conserved bacterial lipoproteins of invading pathogens. The lipid anchor attaches lipoproteins to the cytoplasmic membrane and prevents their release from the bacterial cell envelope. How bacteria release lipoproteins and how these molecules reach TLR2 remain unknown. Staphylococcus aureus has been described to liberate membrane vesicles. The composition, mode of release, and relevance for microbe-host interaction of such membrane vesicles have remained ambiguous. We recently reported that S. aureus can release lipoproteins only when surfactant-like small peptides, the phenol-soluble modulins (PSMs), are expressed. Here we demonstrate that PSM peptides promote the release of membrane vesicles from the cytoplasmic membrane of S. aureus via an increase in membrane fluidity, and we provide evidence that the bacterial turgor is the driving force for vesicle budding under hypotonic osmotic conditions. Intriguingly, the majority of lipoproteins are released by S. aureus as components of membrane vesicles, and this process depends on surfactant-like molecules such as PSMs. Vesicle disruption at high detergent concentrations promotes the capacity of lipoproteins to activate TLR2. These results reveal that vesicle release by bacterium-derived surfactants is required for TLR2-mediated inflammation. IMPORTANCE Our study highlights the roles of surfactant-like molecules in bacterial inflammation with important implications for the prevention and therapy of inflammatory disorders. It describes a potential pathway for the transfer of hydrophobic bacterial lipoproteins, the major TLR2 agonists, from the cytoplasmic membrane of Gram-positive bacteria to the TLR2 receptor at the surface of host cells. Moreover, our study reveals a molecular mechanism that explains how cytoplasmic and membrane-embedded bacterial proteins can be released by bacterial cells without using any of the typical protein secretion routes, thereby contributing to our understanding of the processes used by bacteria to communicate with host organisms and the environment.


Author(s):  
Melisa Selly Liswandari

UJI AKTIVITAS ANTIBAKTERI ALGA HIJAU (Ulva sp.) DARI PANTAI SORIDO BIAK TERHADAP BAKTERI Escherichia coli  DAN Staphylococcus aureus Melisa Selly Liswandari1), Daniel Lantang2), Septriyanto Dirgantara1)1)Program Studi Farmasi, Fakultas MIPA Universitas Cenderawasih, Jayapura2)Jurusan Biologi, Fakultas MIPA Universitas Cenderawasih, Jayapura, Kampus UNCEN Waena. Jl Perumnas III Waena Jayapura 99351 PapuaEmail*: [email protected]  ABSTRACT The green algae (Ulva sp.) are potentially as antibacterial agent because it contains triterpenoids, flavonoids, and saponins. The objective of this research are to know antibacterial activity of green algae (Ulva sp.) extracts using different levels of solvent polarity and the most effective concentration inhibits the growth of bacterial Escherichia coli and Staphylococcus aureus. Green algae (Ulva sp.) extracted by stratified soxletation method using solvent, eq diethyl ether, ethyl acetate, and ethanol 96%. Test antibacterial activity using the disc diffusion method. This research using the of CRD (Completely Randomize Design) with 7 treatments was concentration of 100 ppm, 250 ppm, 500 ppm, 750 ppm, 1000 ppm, positive control (ciprofloxacin 5µg) and negative control (aquades steril) with 3 repetitions. The data was analyzed using ANOVA and continued by HSD (Honestly Significant Difference) test with 95% confidence level. The result was demonstrated that extract green algae (Ulva sp.) the most effective to inhibits the growth of bacterial Escherichia coli is ethyl acetate extract with concentration 250 ppm (9,26 mm) and bacterial Staphylococcus aureus is ethanol 96% extract with concentration 750 ppm (9,57 mm). Keywords : Ulva sp., antibacterial agent, Escherichia coli, Staphylococcus aureus. ABSTRAK             Alga hijau (Ulva sp.) berpotensi sebagai antibakteri karena mengandung triterpenoid, flavonoid, dan saponin. Tujuan dari penelitian ini adalah untuk mengetahui aktivitas antibakteri ekstrak alga hijau (Ulva sp.) yang menggunakan tingkat kepolaran pelarut berbeda dan konsentrasi yang paling efektif dalam menghambat pertumbuhan bakteri Escherichia coli dan Staphylococcus aureus. Alga hijau (Ulva sp.) diekstraksi dengan metode sokletasi bertingkat menggunakan pelarut dietil eter, etil asetat, dan etanol 96%. Uji aktivitas antibakteri menggunakan metode difusi cakram. Penelitian ini menggunakan RAL dengan 7 perlakuan yaitu konsentrasi 100 ppm, 250 ppm, 500 ppm, 750 ppm, 1000 ppm, kontrol positif (ciprofloxasin 5µg) dan kontrol negatif (akuades steril) dengan 3 pengulangan. Data analisis menggunakan ANOVA dan dilakukan uji lanjut BNJ dengan tingkat kepercayaan 95%. Hasil penelitian menunjukkan bahwa ekstrak alga hijau (Ulva sp.) yang paling efektif untuk menghambat pertumbuhan bakteri Escherichia coli adalah ekstrak etil asetat dengan konsentrasi 250 ppm (9,26 mm) dan bakteri Staphylococcus aureus adalah ekstrak etanol 96% dengan konsentrasi 750 ppm (9,57 mm). Kata kunci : Ulva sp., antibakteri, Escherichia coli, Staphylococcus aureus. 


2018 ◽  
Vol 6 (2) ◽  
pp. 212
Author(s):  
Elok Dea Orens Ubung Wisnu ◽  
Indah Purnama Sary ◽  
Dwi Koko Pratoko

N-phenylbenzamide is benzamide derivatives, which is potential as an antibacterial agent. N-phenyl-4-chlorobenzamide is N-phenylbenzamide derivative that substitued by chloro to the para position and it was expected to enhance the antibacterial activity. N-phenyl-4-chlorobenzamide was synthesized by reacting 1,3-diphenyilthiourea and 4-chlorobenzoil chloride. This compound has been purified and provided 53% of product with crystal shape, white color, and melting point of 195-197 oC. The purification of this compound was confirmed by TLC and the structure was identified by 1H-NMR, 13C-NMR, and FTIR spectroscopy. This compound was tested for its activity against gram positive bacteria Staphylococcus aureus and gram negative bacteria Pseudomonas aeruginosa, evaluated by well diffusion method and the result showed no activity against both Staphylococcus aureus and Pseudomonas aeruginosa.   Keywords: N-phenyl-4-chlorobenzamide, synthesis, antibacterial activity


mBio ◽  
2015 ◽  
Vol 6 (4) ◽  
Author(s):  
Richard Wheeler ◽  
Robert D. Turner ◽  
Richard G. Bailey ◽  
Bartłomiej Salamaga ◽  
Stéphane Mesnage ◽  
...  

ABSTRACTMost bacterial cells are enclosed in a single macromolecule of the cell wall polymer, peptidoglycan, which is required for shape determination and maintenance of viability, while peptidoglycan biosynthesis is an important antibiotic target. It is hypothesized that cellular enlargement requires regional expansion of the cell wall through coordinated insertion and hydrolysis of peptidoglycan. Here, a group of (apparent glucosaminidase) peptidoglycan hydrolases are identified that are together required for cell enlargement and correct cellular morphology ofStaphylococcus aureus, demonstrating the overall importance of this enzyme activity. These are Atl, SagA, ScaH, and SagB. The major advance here is the explanation of the observed morphological defects in terms of the mechanical and biochemical properties of peptidoglycan. It was shown that cells lacking groups of these hydrolases have increased surface stiffness and, in the absence of SagB, substantially increased glycan chain length. This indicates that, beyond their established roles (for example in cell separation), some hydrolases enable cellular enlargement by making peptidoglycan easier to stretch, providing the first direct evidence demonstrating that cellular enlargement occurs via modulation of the mechanical properties of peptidoglycan.IMPORTANCEUnderstanding bacterial growth and division is a fundamental problem, and knowledge in this area underlies the treatment of many infectious diseases. Almost all bacteria are surrounded by a macromolecule of peptidoglycan that encloses the cell and maintains shape, and bacterial cells must increase the size of this molecule in order to enlarge themselves. This requires not only the insertion of new peptidoglycan monomers, a process targeted by antibiotics, including penicillin, but also breakage of existing bonds, a potentially hazardous activity for the cell. UsingStaphylococcus aureus, we have identified a set of enzymes that are critical for cellular enlargement. We show that these enzymes are required for normal growth and define the mechanism through which cellular enlargement is accomplished, i.e., by breaking bonds in the peptidoglycan, which reduces the stiffness of the cell wall, enabling it to stretch and expand, a process that is likely to be fundamental to many bacteria.


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