scholarly journals Antimicrobial activity of camphor tree silver nano-particles against foulbrood diseases and finding out new strain of Serratia marcescens as a secondary infection on honeybee larvae

Author(s):  
Saad Hamdy Daif Masry ◽  
Tarek Hosny Taha ◽  
William A. Botros ◽  
Hatem Mahfouz ◽  
Saad Naser Al-Kahtani ◽  
...  
Author(s):  
A. O. Akintola ◽  
A. M. Azeez ◽  
B. D. Kehinde ◽  
I. C. Oladipo

Silver nano particles (AgNPs) were green synthesized using Adansonia digitata leaf extract. The synthesized silver nano particles were characterized in terms of synthesis, size, shape, morphology and capping functionalities by UV-Visible Spectroscopy, Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). Antimicrobial activity of the synthesized silver nano particles was investigated by well diffusion method. The antibacterial activity of the nano particle was studied against Staphylococcus aureus, Escherichia coli, Bacillus subtilis, Pseudomonas aeurigunosa, Salmonella typhi and Klebsiella pneumonae while the antifungal activity was studied against Candida albicans, Aspergillus niger, Penicillum notatum and Rhizopus stolomifer. The synthesized AgNPs was active against all the studied microorganisms. Staphylococcus aureus was the most susceptible bacterium (inhibition zones ranging from 12.00 to 28.00 mm, MIC: 30 µl, MBC: 50 µl) while Aspergillus niger was the most susceptible fungi (inhibition zones ranging from 10.00 to 18.00 mm, MIC: 90 µl, MFC: 120 µl. In conclusion the synthesized silver nanoparticles was found to have antimicrobial activity against the pathogenic bacteria and fungi tested and hence has a great potential in biomedical application for the treatment of microbial infections.


2017 ◽  
Vol 199 (21) ◽  
Author(s):  
Lauren M. Petersen ◽  
Kaitlyn LaCourse ◽  
Tim A. Schöner ◽  
Helge Bode ◽  
Louis S. Tisa

ABSTRACT Hemolysins are important virulence factors for many bacterial pathogens, including Serratia marcescens. The role of the major hemolysin gene in the insect pathogen Serratia sp. strain SCBI was investigated using both forward and reverse-genetics approaches. Introduction of the major hemolysin gene into Escherichia coli resulted in a gain of both virulence and hemolytic activity. Inactivation of this hemolysin in Serratia sp. SCBI resulted in a loss of hemolysis but did not attenuate insecticidal activity. Unexpectedly, inactivation of the hemolysin gene in Serratia sp. SCBI resulted in significantly increased motility and increased antimicrobial activity. Reverse transcription-quantitative PCR (qRT-PCR) analysis of mutants with a disrupted hemolysin gene showed a dramatic increase in mRNA levels of a nonribosomal peptide synthetase gene, swrA, which produces the surfactant serrawettin W2. Mutation of the swrA gene in Serratia sp. SCBI resulted in highly varied antibiotic activity, motility, virulence, and hemolysis phenotypes that were dependent on the site of disruption within this 17.75-kb gene. When introduced into E. coli, swrA increases rates of motility and confers antimicrobial activity. While it is unclear how inactivation of the major hemolysin gene influences the expression of swrA, these results suggest that swrA plays an important role in motility and antimicrobial activity in Serratia sp. SCBI. IMPORTANCE The opportunistic Gram-negative bacteria of the genus Serratia are widespread in the environment and can cause human illness. A comparative genomics analysis between Serratia marcescens and a new Serratia species from South Africa, termed Serratia sp. strain SCBI, shows that these two organisms are closely related but differ in pathogenesis. S. marcescens kills Caenorhabditis nematodes, while Serratia sp. SCBI is not harmful and forms a beneficial association with them. This distinction presented the opportunity to investigate potential differences in regulation of common virulence mechanisms between these two species. With the emergence of antibiotic-resistant microorganisms, there is a widespread need to understand the regulation of pathogenesis. The significance of this study is the presentation of evidence for cross-pathway regulation of virulence factors and how the elimination of one mechanism may be compensated for by the upregulation of others.


RSC Advances ◽  
2014 ◽  
Vol 4 (29) ◽  
pp. 15022-15029 ◽  
Author(s):  
Totan Ghosh ◽  
Sandeep Kumar Dash ◽  
Prateeti Chakraborty ◽  
Averi Guha ◽  
Kenji Kawaguchi ◽  
...  

Two varieties of Co3O4 nano particles (Co3O4-I and Co3O4-II) have been synthesized from two different precursors using a pyrolytic technique and their magnetic and in vitro antimicrobial activity have been investigated.


Author(s):  
Volodymyr Toropin ◽  
Bohdan Murashevych ◽  
Dmytro Stepanskyi ◽  
Mykola Toropin ◽  
Henadii Kremenchutskiy ◽  
...  

The search for new effective means for combating pathogenic microorganisms is one of the most important tasks of modern medicine. The main reason for the need for such studies is the obvious tendency to increase of the resistance of pathogenic microorganisms to the compounds used for these purposes, observed over the past few decades. Leading international organizations recognize the problem of the evolution of «superbacteria» as a global threat to humanity. Compounds of active chlorine are extremely effective biocidal agents. However, for the number of reasons, classic chlorine-active drugs (solutions of sodium hypochlorite, hypochlorous acid, chloramines, etc.) have limited use in medicine. This work is aimed at the study of the properties of new forms of active chlorine. Technology has been developed for the chemical immobilization of active chlorine donor groups on granular and fibrous polymer carriers. Polymers have been obtained, which contain 5-20 % of the active chlorine and are highly stable. It was shown that upon contact of such polymers with a medium containing ammonium salts or impurities of protein structure, emission of active chlorine occurs in an amount equivalent to the quantity of such impurities. Methods have been developed for the express manufacture of high-purity solutions of active chlorine (hypochlorous acid, chlortaurin) by activating these polymers with special activators. High antimicrobial activity of such solutions has been proved. It was shown that the polymers themselves also exhibit high microbicidal activity. The possibility of using fibrous forms of chlorine-active polymers as an antimicrobial component of a wound dressing has been investigated. The absence of toxicity of such dressings has been proved. It has been shown that the application of dressings on uninfected wounds speeds up the healing process. The application of dressings on infected wounds prevents the progress of inflammatory processes and significantly reduces the number of pathogenic microorganisms in wound secretions. Thus, synthesized polymers with immobilized active chlorine may be promising for use in water and air disinfection systems, for detoxification of hospital effluents, the rapid production of antimicrobial solutions, as well as for the manufacture of prolonged-action antiseptic wound dressings that protect wounds from secondary infection, that is especially important for military and disaster medicine. Keywords: disinfection, antiseptics, active chlorine, immobilization, antiseptic solutions, antimicrobial activity, reparative activity, wound dressings. For citation: Toropin VM, Murashevych BV, Stepanskyi DO, Toropin MV, Kremenchutskiy HM., Burmistrov KS. New forms of immobilized active chlorine and its potential applications in medicine. Journal of the National Academy of Medical Sciences of Ukraine. 2019;25(3):340–52


2017 ◽  
Vol 13 (3) ◽  
pp. 6065-6075
Author(s):  
Manikandan Kandasamy

  In this research work, the effect of Tungsten-doping on the crystal structure, morphology and antimicrobial of titanium dioxide nanoparticles were studied. The pure and different weight % of tungsten doped TiO2 nanoparticles were synthesized by sol–gel method and calcinated at 600°C for 5 hours. The synthesised products have been characterized by X-ray Diffraction studies (XRD), Field Emission Scanning Electron Microscopy (FE-SEM), Elemental analysis (EDXA), Ultra Violet Visible Spectroscopy (UV-Vis), Photoluminescence Spectra (PL), High Resolution Transmission Spectroscopy (HRTEM) and Fourier Transform Infra Red Spectroscopy (FT-IR). XRD pattern of pure TiO2 and 1 weight % W-doped TiO2nanoparticles confirms the anatase structure and increase in the W-doping changes the phase of TiO2 to rutile. Average crystallite size of synthesized nanoparticles was determined using the Debye–Scherrer formula. The crystallite size obtained for pure TiO2 is in the range from 29 nm to 39 nm and W-doped TiO2 is varied from 28 to 34 nm. The SEM images show the agglomerated particles of spherical-like morphology. Optical property and direct bandgap of pure and W-doped TiO2nanoparticles also further characterised by UV–Vis Spectroscopy. The images of HRTEM clearly confirm that particles present in the W-doped TiO2 powdered sample is nanosized particles. The Kirby Bauer Agar Well Diffusion Assay  method was employed to explore antimicrobial activity of nanosized pure and W-doped TiO2 colloidal suspension against the test microorganisms two Gram positive bacteria(Staphylococcus aureus, Bacillus subtilis),two Gram negative Bacteria(Escherichia coli, Pseudomonas aeruginosa),and two fungi(Candida albicans, Aspergillus niger). It shows that the W- doped TiO2 nanoparticles inhibited the multiplication and growth of the above mentioned test bacteria and fungi. Antimicrobial activity was found against all tested microorganisms which confirmed that W-doped TiO2 nanoparticles possess high antimicrobial activity compared to pure TiO2 nanoparticles.   


2017 ◽  
Vol 6 (3) ◽  
pp. 297-304 ◽  
Author(s):  
Sabita Singh ◽  
Kunal Biswas ◽  
Sanhita Chowdhury ◽  
Yugal Kishore Mohanta ◽  
Jaya Bandyopadhyay

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