scholarly journals Use of Aerial Roots of Ficus benghalensis for Green Synthesis of Silver Nanoparticles with Enhanced Antibacterial Activity

2021 ◽  
pp. 257-267
Author(s):  
Tarannum Rashid Patave ◽  
Aquil-Ur Rahim Siddiqui
Keyword(s):  
Staphylococcus Aureus ◽  
Silver Nanoparticles ◽  
High Resolution ◽  
High Speed ◽  
Bacterial Infections ◽  
Research Work ◽  
Silver Ions ◽  
Ficus Benghalensis ◽  
Aerial Roots

Basically, nanosubstances are developed by a variety of chemical methods which are not environmentally providential. Aim: The present research work deals with the synthesis of silver nanoparticles using the aerial root of Ficus benghalensis extract. The absolute reduction of silver ions was observed after 48 h of reaction when extact combine with aqueous solution of Silver nitrate. The visual colour changes were observed during the reduction of silver ion into the silver nanoparticles in the reaction mixture allows producing dark brown colour. The formed silver nanoparticles was purified by high speed centrifugation, collected and stored for further characterization. Methodology: The formation of silver nanoparticles was confirmed by UV-Visible spectroscopy, and characterised by X-Ray Diffraction (XRD) pattern, FTIR, High Resolution Transmission Electron Microscopy (HRTEM), Zeta potentiometry, ICP-AES. Results: The results showed that UV peak at 437.5 nm, the silver content estimation by ICP-AES was found to be 413.06 µg/mL and images were recorded by using High resolution TEM. Synthesized AgNPs were found to be effective against micro-organisms responsible for bacterial infections like Staphylococcus aureus, Pseudomonas aeruginosa, E. coli and Methicillin resistant Staphylococcus Aureus (MRSA). Further In-vitro cytocompatibility studies showed lack of toxicity at even higher concentration.  Conclusion: Still, these Silver Nanoparticles are cytotoxic in nature and could serve as a good green method for synthesis of silver nanoparticle by using plant extract. 

Antimicrobial Activity of PET-Silver Nanocomposite Filaments

2018 ◽  
Vol 930 ◽  
pp. 212-217
Author(s):  
Marcos Antônio Guerra ◽  
Jeferson Prado Swerts ◽  
Mei Abe Funcia ◽  
Maria Gabriela Nogueira Campos
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Silver Nanoparticles ◽  
Silver Ions ◽  
Dermal Fibroblasts ◽  
Klebsiella Pneumonia ◽  
Dyeing Process ◽  
Colony Forming Units ◽  
Silver Nanocomposite

This study evaluated the antimicrobial activity of PET-Silver nanocomposite filaments at different concentrations (0, 0.180%, 0.135%, 0.090%, 0.045% and 0.022% w/w) of silver nanoparticles in order to determine the minimum inhibitory concentration and minimum bactericidal concentration of silver incorporated in the PET matrix. The in vitro antibacterial activity was evaluated by the AATCC standard 100: 2012 method, against Staphylococcus aureus ATCC 6538, and Klebsiella pneumonia ATCC 4532. The filaments were tested after one and twenty-one months of preparation to evaluate the effect of time on the antimicrobial activity of the nanocomposites. Moreover, the antimicrobial activity was also evaluated after dyeing the filaments. The silver-free PET filaments have not demonstrated antimicrobial activity and cytotoxicity against human dermal fibroblasts. Nevertheless, excepted for the filament with 0.022% of silver nanoparticles, all PET-Silver nanocomposites reduced more than 99% the colony-forming units (CFU) of Staphylococcus aureus and Klebsiella pneumonia after one and twenty-one months of preparation. This suggests that the MIC of silver nanoparticles incorporated in the PET matrix is lower than 220 ppm (w/w) and the MBC is between 0.022 and 0.045% (w/w). However, after the dyeing process, no antimicrobial activity was observed for any PET-Silver nanocomposite filaments. This may be attributed to the release of silver from the PET matrix during the dyeing process or to the reaction/inactivation of the silver ions by the salts used in this chemical treatment.

scholarly journals Bacteriocins of Non-aureus Staphylococci Isolated from Bovine Milk

2017 ◽  
Vol 83 (17) ◽  
Author(s):  
Domonique A. Carson ◽  
Herman W. Barkema ◽  
Sohail Naushad ◽  
Jeroen De Buck
Keyword(s):  
Staphylococcus Aureus ◽  
Bacterial Infections ◽  
Genome Mining ◽  
Bovine Milk ◽  
Gene Clusters ◽  
Antibiotic Use ◽  
Content Type ◽  
Treatment And Prevention ◽  
Whole Genomes

ABSTRACT Non-aureus staphylococci (NAS), the bacteria most commonly isolated from the bovine udder, potentially protect the udder against infection by major mastitis pathogens due to bacteriocin production. In this study, we determined the inhibitory capability of 441 bovine NAS isolates (comprising 26 species) against bovine Staphylococcus aureus. Furthermore, inhibiting isolates were tested against a human methicillin-resistant S. aureus (MRSA) isolate using a cross-streaking method. We determined the presence of bacteriocin clusters in NAS whole genomes using genome mining tools, BLAST, and comparison of genomes of closely related inhibiting and noninhibiting isolates and determined the genetic organization of any identified bacteriocin biosynthetic gene clusters. Forty isolates from 9 species (S. capitis, S. chromogenes, S. epidermidis, S. pasteuri, S. saprophyticus, S. sciuri, S. simulans, S. warneri, and S. xylosus) inhibited growth of S. aureus in vitro, 23 isolates of which, from S. capitis, S. chromogenes, S. epidermidis, S. pasteuri, S. simulans, and S. xylosus, also inhibited MRSA. One hundred five putative bacteriocin gene clusters encompassing 6 different classes (lanthipeptides, sactipeptides, lasso peptides, class IIa, class IIc, and class IId) in 95 whole genomes from 16 species were identified. A total of 25 novel bacteriocin precursors were described. In conclusion, NAS from bovine mammary glands are a source of potential bacteriocins, with >21% being possible producers, representing potential for future characterization and prospective clinical applications. IMPORTANCE Mastitis (particularly infections caused by Staphylococcus aureus) costs Canadian dairy producers $400 million/year and is the leading cause of antibiotic use on dairy farms. With increasing antibiotic resistance and regulations regarding use, there is impetus to explore bacteriocins (bacterially produced antimicrobial peptides) for treatment and prevention of bacterial infections. We examined the ability of 441 NAS bacteria from Canadian bovine milk samples to inhibit growth of S. aureus in the laboratory. Overall, 9% inhibited growth of S. aureus and 58% of those also inhibited MRSA. In NAS whole-genome sequences, we identified >21% of NAS as having bacteriocin genes. Our study represents a foundation to further explore NAS bacteriocins for clinical use.

scholarly journals Staphylococcus aureus growth delay after exposure to low fluencies of blue light (470 nm)

2020 ◽  
Author(s):  
I. D. C. Galo ◽  
B. E. De Lima ◽  
T. G. Santos ◽  
A. Braoios ◽  
R. P. Prado ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Blue Light ◽  
Bacterial Infections ◽  
Growth Delay ◽  
Control Group ◽  
Prolonged Incubation ◽  
Bacterial Cultures ◽  
Experimental Approaches ◽  
Prolonged Hospital

Abstract Antibiotic resistance is one of the greatest challenges to treat bacterial infections worldwide, leading to increase in medical expenses, prolonged hospital stay and increased mortality. The use of blue light has been suggested as an innovative alternative to overcome this problem. In this study we analyzed the antibacterial effect of blue light using low emission parameters on Staphylococcus aureus cultures. In vitro bacterial cultures were used in two experimental approaches. The first approach included single or fractionated blue light application provided by LED emitters (470 nm), with the following fluencies: 16.29, 27.16 and 54.32 J/cm2. For the second approach a power LED (470 nm) was used to deliver 54.32 J/cm2 fractionated in 3 applications. Our results demonstrated that bacterial cultures exposed to fractionated blue light radiation exhibited significantly smaller sizes colonies than the control group after 24 h incubation, however the affected bacteria were able to adapt and continue to proliferate after prolonged incubation time. We could conclude that the hypothetical clinical use of low fluencies of blue light as an antibacterial treatment is risky, since its action is not definitive and proves to be ineffective at least for the strain used in this study.

Silver nanoparticles used to counter Monilinia fructicola fungicide-resistance and reduce fungicide environmental footprint 

2021 ◽  
Author(s):  
Constantinos Chrysikopoulos ◽  
Anastasios A. Malandrakis ◽  
Nektarios Kavroulakis ◽  
Anthi Stefanarou
Keyword(s):  
Silver Nanoparticles ◽  
Control Plant ◽  
Resistance Mutation ◽  
Silver Ions ◽  
Apple Fruit ◽  
Ag Nps ◽  
Gene Target ◽  
Benzimidazole Fungicides

<div><span>The potential of silver nanoparticles (Ag-NPs) to control plant pathogen <em>Monilia</em><em>fructicola </em>and to deter environmental contamination by reducing fungicide doses was evaluated <em>in vitro </em>and <em>in vivo. </em> </span>F<span>ungitoxicity screening </span>of <em><span>M. fructicola </span></em><span>isolates resulted in the detection of 18 benzimidazole-resistant (BEN-R) isolates with reduced sensitivity to fungicides  thiophanate methyl (TM)  and carbendazim. All resistant isolates caried the E198A resistance mutation in their </span><em><span>β</span>-</em>tubulin gene, target site of the benzimidazole fungicides. <span>Ag-NPs could effectively control both sensitive (BEN-S) and resistant isolates while the combination of Ag-NPs with TM significantly enhanced their fungitoxic effect both <em>in vitro </em>and in apple fruit tests. The positive correlation observed between Ag-NPs and TM+Ag-NPs treatments indicates a mixture-enhanced Ag-NPs activity/availability as a possible mechanism of synergy. No correlation between Ag-NPs  and AgNO<sub>3 </sub>could  be found suggesting difference(s) in the fungitoxic mechanism of action between Nps and their bulk/ionic counterparts. Indications of the involvement of energy (ATP) metabolism in the mode of action of Ag-NPs were also evident by the synergy observed between Ag-NPs and the </span>oxidative phosphorylation<span>-uncoupler fluazinam (FM) against both BEN-R and BEN-S phenotypes. The role of silver ions release on the inhibitory action of Ag-NPs against the fungusis probably limited since the AgNPs/NaCl combination enhanced fungitoxicity, a fact that could not be justified by the expected binding of silver with chlorine ions. Concluding, Ag-NPs can be effectively used as a means of controlling both BEN-S and BEN-R <em>M. </em><em>fructicola </em>isolates </span>while <span>their combination with conventional fungicides should aid anti-resistant strategies and reduce the environmental impact of synthetic fungicides by reducing effective doses to the control the pathogen.</span></div>

scholarly journals Efficacy of Bacteriophages Against Staphylococcus aureus Isolates from Bovine Mastitis

2020 ◽  
Vol 13 (3) ◽  
pp. 35 ◽  
Author(s):  
Isabel Titze ◽  
Tatiana Lehnherr ◽  
Hansjörg Lehnherr ◽  
Volker Krömker
Keyword(s):  
Staphylococcus Aureus ◽  
Host Range ◽  
Bacterial Infections ◽  
Plaque Assay ◽  
Bovine Milk ◽  
Bovine Mastitis ◽  
Raw Milk ◽  
Pasteurized Milk

The lytic efficacy of bacteriophages against Staphylococcus aureus isolates from bovine milk was investigated in vitro, regarding possible applications in the therapy of udder inflammation caused by bacterial infections (mastitis). The host range of sequenced, lytic bacteriophages was determined against a collection of 92 Staphylococcus (S.) aureus isolates. The isolates originated from quarter foremilk samples of clinical and subclinical mastitis cases. A spot test and a subsequent plaque assay were used to determine the phage host range. According to their host range, propagation and storage properties, three phages, STA1.ST29, EB1.ST11, and EB1.ST27, were selected for preparing a bacteriophage mixture (1:1:1), which was examined for its lytic activity against S. aureus in pasteurized and raw milk. It was found that almost two thirds of the isolates could be lysed by at least one of the tested phages. The bacteriophage mixture was able to reduce the S. aureus germ density in pasteurized milk and its reduction ability was maintained in raw milk, with only a moderate decrease compared to the results in pasteurized milk. The significant reduction ability of the phage mixture in raw milk promotes further in vivo investigation.

230 GENERATION OF PUTATIVE RABBIT EMBRYONIC STEM CELLS

2007 ◽  
Vol 19 (1) ◽  
pp. 231
Author(s):  
S. Wang ◽  
X. Tang ◽  
Y. Niu ◽  
H. Chen ◽  
T. Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Embryonic Stem Cells ◽  
High Speed ◽  
Es Cells ◽  
Research Work ◽  
Embryonic Stem ◽  
Morphological Characteristics ◽  
Mouse Escs

The rabbit, as a laboratory animal model, has several advantages in the study of human physiological disorders. In this study, stable putative pluripotent rabbit embryonic stem cells (rESCs) were derived from in vivo-fertilized and in vitro-cultured blastocysts. The rabbit ICMs were obtained by 0.05% trypsin–0.008% EDTA treatment and mechanical separation; the ES-like cell colonies seen several days later. ICM-derived outgrowths which were treated with 5 mg/mL-1 dispase, followed by 0.05% trypsin–0.008% EDTA, were mechanically disaggregated into small clumps and reseeded on MEFs. The putative ES cell lines maintained expression of pluripotent cells markers and normal XY karyotype for long periods of culture (>1 month). The putative rESCs expressed alkaline phosphatase, transcription factor Oct-4, stage-specific embryonic antigens (SSEA-1, SSEA-3, and SSEA-4), and tumor-related antigens (TRA-1-60 and TRA-1-81). The morphological characteristics of the putative ESCs are closer to those of human ESCs; their high speed of proliferation, however, is closer to that of mouse ESCs. Putative rabbit ESCs were induced to differentiate into many cell types including trophoblast cells, similar to primate ESCs, in vitro, and formed teratomas with derivatives of the 3 major germ layers in vivo when injected into SCID mice. Using RT-PCR measurement, but with some differences in ligands and inhibitors, and comparing with human and mouse ESCs, the putative rabbit ESCs expressed similar genes related to pluripotency (Oct-4, Nanog, SOX2, and UTF-1) and similar genes of FGF, WNT, and TGF signaling pathways related to the proliferation and self-renewal. Our further research work showed that TGF beta and FGF pathways cooperate to maintain pluripotency of rabbit ESCs similar to those of human ES cells.

scholarly journals INVESTIGATION OF PHARMACOGNOSTICAL, PHYTOCHEMICAL, AND PHARMACOLOGICAL ACTIVITY OF AERIAL ROOTS OF FICUS BENGHALENSIS LINN

2018 ◽  
Vol 11 (10) ◽  
pp. 279
Author(s):  
Kamalika Mazumder ◽  
Himangshu S Maji ◽  
Nripendra N Bala
Keyword(s):  
Antioxidant Activity ◽  
Ethyl Acetate ◽  
Analgesic Activity ◽  
Ethyl Acetate Extract ◽  
Microscopic Investigation ◽  
Tail Flick ◽  
Ficus Benghalensis ◽  
Aerial Roots

Objective: Ficus benghalensis Linn. (Moraceae family) is commonly known as banyan tree in English, which is used traditionally in India. The literature survey showed that the aerial roots of this plant are yet to be explored. Our main interest is to evaluate its pharmacognostic and phytochemical character by the standard monograph and to explore its in vitro antioxidant and in vivo analgesic activity study with ethyl acetate extract.Methods: Pharmacognostic evaluation and phytochemical screening have been done using standard monograph. An in vitro antioxidant activity using ethyl acetate extract has been done using four different methods. In vivo analgesic activity of the ethyl acetate extract has been evaluated by acetic acid-induced writhing test in mice and tail flick method.Results: Aerial roots of F. benghalensis have been found the rich source of steroidal glycosides, cardiac glycosides, flavonoids, tri-terpenoids, and phenols. The presence of phellem, phellogen, xylem, and phloem has been found after microscopic investigation. All the pharmacognostic parameters proved its purity. Results showed the absence of heavy metals. The ethyl acetate extract has shown potent antioxidant activity at 100 μg/ml concentration and higher analgesic activity at the concentration of 400 mg/kg than 200 mg/kg.Conclusion: Pharmacognostic characteristics and phytochemical properties revealed in this study could be used for the pharmacopoeial standard. Ethyl acetate extract showed potent antioxidant and analgesic activity.

scholarly journals Formulation of pH-Responsive Quatsomes from Quaternary Bicephalic Surfactants and Cholesterol for Enhanced Delivery of Vancomycin against Methicillin Resistant Staphylococcus aureus

Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1093
Author(s):  
Daniel Hassan ◽  
Calvin A. Omolo ◽  
Victoria Oluwaseun Fasiku ◽  
Ahmed A Elrashedy ◽  
Chunderika Mocktar ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
High Resolution ◽  
Antimicrobial Resistance ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Human Beings ◽  
Ph Responsive ◽  
Methicillin Resistant ◽  
13C Nuclear Magnetic Resonance

Globally, human beings continue to be at high risk of infectious diseases caused by methicillin-resistant Staphylococcus aureus (MRSA); and current treatments are being depleted due to antimicrobial resistance. Therefore, the synthesis and formulation of novel materials is essential for combating antimicrobial resistance. The study aimed to synthesize a quaternary bicephalic surfactant (StBAclm) and thereof to formulate pH-responsive vancomycin (VCM)-loaded quatsomes to enhance the activity of the antibiotic against MRSA. The surfactant structure was confirmed using 1H, 13C nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FT-IR), and high-resolution mass spectrometry (HRMS). The quatsomes were prepared using a sonication/dispersion method and were characterized using various in vitro, in vivo, and in silico techniques. The in vitro cell biocompatibility studies of the surfactant and pH-responsive vancomycin-loaded quatsomes (VCM-StBAclm-Qt1) revealed that they are biosafe. The prepared quatsomes had a mean hydrodynamic diameter (MHD), polydispersity index (PDI), and drug encapsulation efficiency (DEE) of 122.9 ± 3.78 nm, 0.169 ± 0.02 mV, and 52.22 ± 8.4%, respectively, with surface charge switching from negative to positive at pH 7.4 and pH 6.0, respectively. High-resolution transmission electron microscopy (HR-TEM) characterization of the quatsomes showed spherical vesicles with MHD similar to the one obtained from the zeta-sizer. The in vitro drug release of VCM from the quatsomes was faster at pH 6.0 compared to pH 7.4. The minimum inhibitory concentration (MIC) of the drug loaded quatsomes against MRSA was 32-fold and 8-fold lower at pH 6.0 and pH 7.4, respectively, compared to bare VCM, demonstrating the pH-responsiveness of the quatsomes and the enhanced activity of VCM at acidic pH. The drug-loaded quatsomes demonstrated higher electrical conductivity and a decrease in protein and deoxyribonucleic acid (DNA) concentrations as compared to the bare drug. This confirmed greater MRSA membrane damage, compared to treatment with bare VCM. The flow cytometry study showed that the drug-loaded quatsomes had a similar bactericidal killing effect on MRSA despite a lower (8-fold) VCM concentration when compared to the bare VCM. Fluorescence microscopy revealed the ability of the drug-loaded quatsomes to eradicate MRSA biofilms. The in vivo studies in a skin infection mice model showed that groups treated with VCM-loaded quatsomes had a 13-fold decrease in MRSA CFUs when compared to the bare VCM treated groups. This study confirmed the potential of pH-responsive VCM-StBAclm quatsomes as an effective delivery system for targeted delivery and for enhancing the activity of antibiotics.

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