scholarly journals Evaluation of Ultrasound-Induced Damage to Escherichia coli and Staphylococcus aureus by Flow Cytometry and Transmission Electron Microscopy

2016 ◽  
Vol 82 (6) ◽  
pp. 1828-1837 ◽  
Author(s):  
Jiao Li ◽  
Juhee Ahn ◽  
Donghong Liu ◽  
Shiguo Chen ◽  
Xingqian Ye ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Transmission Electron Microscopy ◽  
Flow Cytometry ◽  
Cytoplasmic Membrane ◽  
Ultrasound Treatment ◽  
Cellular Damage ◽  
Content Type ◽  
Transmission Electron

ABSTRACTAs a nonthermal sterilization technique, ultrasound has attracted great interest in the field of food preservation. In this study, flow cytometry and transmission electron microscopy were employed to investigate ultrasound-induced damage toEscherichia coliandStaphylococcus aureus. For flow cytometry studies, single staining with propidium iodide (PI) or carboxyfluorescein diacetate (cFDA) revealed that ultrasound treatment caused cell death by compromising membrane integrity, inactivating intracellular esterases, and inhibiting metabolic performance. The results showed that ultrasound damage was independent of initial bacterial concentrations, while the mechanism of cellular damage differed according to the bacterial species. For the Gram-negative bacteriumE. coli, ultrasound worked first on the outer membrane rather than the cytoplasmic membrane. Based on the double-staining results, we inferred that ultrasound treatment might be an all-or-nothing process: cells ruptured and disintegrated by ultrasound cannot be revived, which can be considered an advantage of ultrasound over other nonthermal techniques. Transmission electron microscopy studies revealed that the mechanism of ultrasound-induced damage was multitarget inactivation, involving the cell wall, cytoplasmic membrane, and inner structure. Understanding of the irreversible antibacterial action of ultrasound has great significance for its further utilization in the food industry.

scholarly journals Structure-Function Relationship of Antibacterial Synthetic Peptides Homologous to a Helical Surface Region on Human Lactoferrin against Escherichia coli Serotype O111

1998 ◽  
Vol 66 (6) ◽  
pp. 2434-2440 ◽  
Author(s):  
Daniel S. Chapple ◽  
David J. Mason ◽  
Christopher L. Joannou ◽  
Edward W. Odell ◽  
Vanya Gant ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Transmission Electron Microscopy ◽  
Flow Cytometry ◽  
Antibacterial Activity ◽  
Synthetic Peptides ◽  
Membrane Integrity ◽  
E Coli ◽  
Transmission Electron ◽  
Helical Region

ABSTRACT Lactoferricin includes an 11-amino-acid amphipathic alpha-helical region which is exhibited on the outer surface of the amino-terminal lobe of lactoferrin. Synthetic peptides homologous to this region exhibited potent antibacterial activity against a selected range of both gram-negative and gram-positive bacteria. An analog synthesized with methionine substituted for proline at position 26, which is predicted to disrupt the helical region, abolished antibacterial activity against Escherichia coli and considerably reduced antibacterial activity against Staphylococcus aureus and anAcinetobacter strain. The mode of action of human lactoferrin peptide (HLP) 2 against E. coli serotype O111 (NCTC 8007) was established by using flow cytometry, surface plasmon resonance, and transmission electron microscopy. Flow cytometry was used to monitor membrane potential, membrane integrity, and metabolic processes by using the fluorescent probes bis-1,3-(dibutylbarbituric acid)-trimethine oxonol, propidium iodide, and carbonyl cyanide m-chlorophenylhydrazone, respectively. HLP 2 was found to act at the cell membrane, causing complete loss of membrane potential after 10 min and of membrane integrity within 30 min, with irreversible damage to the cell as shown by rapid loss of viability. The number of particles, measured by light scatter on the flow cytometer, dropped significantly, showing that bacterial lysis resulted. The peptide was shown to bind toE. coli O111 lipopolysaccharide by using surface plasmon resonance. Transmission electron microscopy revealed bacterial distortion, with the outer membrane becoming detached from the inner cytoplasmic membrane. We conclude that HLP 2 causes membrane disruption of the outer membrane, resulting in lysis, and that structural considerations are important for antibacterial activity.

Effect of Slightly Acidic Electrolyzed Water for Inactivating Escherichia coli O157:H7 and Staphylococcus aureus Analyzed by Transmission Electron Microscopy

2010 ◽  
Vol 73 (12) ◽  
pp. 2211-2216 ◽  
Author(s):  
SONGJIAN NAN ◽  
YONGYU LI ◽  
BAOMING LI ◽  
CHAOYUAN WANG ◽  
XIAODONG CUI ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Transmission Electron Microscopy ◽  
Treatment Time ◽  
Escherichia Coli O157 ◽  
Electrolyzed Water ◽  
E Coli ◽  
Transmission Electron ◽  
And Staphylococcus Aureus

The use of different available chlorine concentrations (ACCs) of slightly acidic electrolyzed water (SAEW; 0.5 to 30 mg/liter), different treatment times, and different temperatures for inactivating Escherichia coli O157:H7 and Staphylococcus aureus was evaluated. The morphology of both pathogens also was analyzed with transmission electron microscopy. A 3-min treatment with SAEW (pH 6.0 to 6.5) at ACCs of 2 mg/liter for E. coli O157:H7 and 8 mg/liter for S. aureus resulted in 100% inactivation of two cultures (7.92- to 8.75-log reduction) at 25°C. The bactericidal activity of SAEW was independent of the treatment time and temperature at a higher ACC (P > 0.05). E. coli O157:H7 was much more sensitive than S. aureus to SAEW. The morphological damage to E. coli O157:H7 cells by SAEW was significantly greater than that to S. aureus cells. At an ACC as high as 30 mg/liter, E. coli O157:H7 cells were damaged, but S. aureus cells retained their structure and no cell wall damage or shrinkage was observed. SAEW with a near neutral pH may be a promising disinfectant for inactivation of foodborne pathogens.

Flow Cytometry and Electron Microscopy Study of Staphylococcus aureus and Escherichia coli Treated with Mdc-Hly

2015 ◽  
Vol 21 (2) ◽  
pp. 351-357 ◽  
Author(s):  
Xuemei Lu ◽  
Xiaobao Jin ◽  
Jiayong Zhu
Keyword(s):  
Electron Microscopy ◽  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Flow Cytometry ◽  
Foodborne Pathogens ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Antibacterial Mechanism ◽  
Transmission Electron ◽  
Clinical Environments

AbstractIn our previous study, a novel hybrid protein combining human lysozyme (Hly) with Musca domestica cecropin (Mdc) was successfully constructed. The broad antibacterial activity against various foodborne pathogens of Mdc-hly suggests its scope as a food preservative. The aim of the present study was to investigate the antibacterial mechanism of the recombinant Mdc-hly. The damage induced by Mdc-hly on Staphylococcus aureus and Escherichia coli was investigated using flow cytometry (FC), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results of FC showed that Mdc-hly causes bacterial membrane permeabilization. SEM and TEM studies revealed that Mdc-hly is capable of damaging both the membrane and the wall of bacteria, resulting in efflux of essential cytoplasmic contents. Both FC and EM revealed that the effects of Mdc-hly were greater than its parental peptides. Understanding the antibacterial mechanism of Mdc-hly is of a great interest in further utilization of its use in treatment of food and in clinical environments.

Characterization of cellular development and fatty acid accumulation in thraustochytrid Aurantiochytrium strains of Taiwan

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Natarajan Velmurugan ◽  
Yesupatham Sathishkumar ◽  
Shashanka Sonowal ◽  
Ka-Lai Pang ◽  
Yang Soo Lee
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Flow Cytometry ◽  
Cell Growth ◽  
Intracellular Lipid ◽  
Fatty Acid Accumulation ◽  
Transmission Electron ◽  
Intracellular Lipid Accumulation ◽  
High Level

Abstract Long-chain saturated and polyunsaturated fatty acids of two new thraustochytrid isolates cultured from Taiwan mangroves, Aurantiochytrium sp. IMB169 and Aurantiochytrium sp. IMB171, were characterized through their cell growth and development in relation to their intracellular lipid accumulation using transmission electron microscopy. Flow cytometry in combination with the lipophilic fluorescent dye BODIPY 505/515 was used to stain and characterize intracellular lipid bodies in the two isolates. The transmission electron microscopy and flow cytometry analyses revealed a progressive accumulation of lipid products in IMB169 and IMB171. Further, selective BODIPY stained cells were successfully separated and enriched using flow cytometry at single cell level. Among the two isolates, IMB169 was found to produce a high level of docosahexaenoic acid. The qualitative and analytical results obtained using electron microscopy and flow cytometry studies were validated by gas chromatography (GC). In addition, a quantitative baseline was established using cell growth, flow cytometry and GC analyses for developing an efficient bioprocessing methodology to selectively enrich thraustochytrids phenotypes with desirable characteristics.

scholarly journals Endlicheria bracteolata (Meisn.) Essential Oil as a Weapon Against Leishmania amazonensis: In Vitro Assay

Molecules ◽  
2019 ◽  
Vol 24 (14) ◽  
pp. 2525 ◽  
Author(s):  
Mariana Margatto Rottini ◽  
Ana Claudia Fernandes Amaral ◽  
José Luiz Pinto Ferreira ◽  
Edinilze Souza Coelho Oliveira ◽  
Jefferson Rocha de Andrade Silva ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Flow Cytometry ◽  
Essential Oil ◽  
Cutaneous Leishmaniasis ◽  
Leishmania Amazonensis ◽  
Vitro Assay ◽  
Transmission Electron ◽  
Biological Potential ◽  
Intracellular Amastigote

The difficulties encountered and the numerous side effects present in the treatment of cutaneous leishmaniasis have encouraged the research for new compounds that can complement or replace existing treatment. The growing scientific interest in the study of plants, which are already used in folk remedies, has led our group to test Endlicheria bracteolata essential oil against Leishmania amazonensis. Several species of the Lauraceae family, or their compounds, have relevant antiprotozoal activities Therefore, the biological potential on L. amazonensis forms from the essential oil of Endlicheria bracteolata leaves was verified for the first time in that work. The antileishmanial activity was evaluated against promastigotes and intracellular amastigotes, and cytotoxicity were performed with J774.G8, which were incubated with different concentrations of E. bracteolata essential oil. Transmission electron microscopy and flow cytometry were performed with E. bracteolata essential oil IC50. Promastigote forms showed E. bracteolata essential oil IC50 of 7.945 ± 1.285 µg/mL (24 h) and 6.186 ± 1.226 µg/mL (48 h), while for intracellular amastigote forms it was 3.546 ± 1.184 µg/mL (24 h). The CC50 was 15.14 ± 0.090 µg/mL showing that E. bracteolata essential oil is less toxic to macrophages than to parasites. Transmission electron microscopy showed that E. bracteolata essential oil treatment is capable of inducing mitochondrial damage to promastigote and intracellular amastigote forms, while flow cytometry showed ΔѰm disruption in treated parasites. These results could bring about new possibilities to develop products based on E. bracteolata essential oil to treat cutaneous leishmaniasis, especially for people who cannot receive the conventional therapy.

scholarly journals In VitroEffects of Novel Ruthenium Complexes in Neospora caninum and Toxoplasma gondii Tachyzoites

2013 ◽  
Vol 57 (11) ◽  
pp. 5747-5754 ◽  
Author(s):  
Fabienne Barna ◽  
Karim Debache ◽  
Carsten A. Vock ◽  
Tatiana Küster ◽  
Andrew Hemphill
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Toxoplasma Gondii ◽  
Neospora Caninum ◽  
Ruthenium Complexes ◽  
Term Treatment ◽  
Content Type ◽  
Transmission Electron ◽  
Long Term Treatment

ABSTRACTUpon the screening of 16 antiproliferative compounds againstToxoplasma gondiiandNeospora caninum, two hydrolytically stable ruthenium complexes (compounds 16 and 18) exhibited 50% inhibitory concentrations of 18.7 and 41.1 nM (T. gondii) and 6.7 and 11.3 nM (N. caninum). To achieve parasiticidal activity with compound 16, long-term treatment (22 to 27 days at 80 to 160 nM) was required. Transmission electron microscopy demonstrated the rapid impact on and ultrastructural alterations in both parasites. These preliminary findings suggest that the potential of ruthenium-based compounds should thus be further exploited.

scholarly journals Ultrastructural Study of Elaeis guineensis (Oil Palm) Leaf and Antimicrobial Activity of its Methanol Extract against Staphylococcus Aureus

2016 ◽  
Vol 12 (3) ◽  
pp. 419-423 ◽  
Author(s):  
Amala Rajoo ◽  
Sreenivasan Sasidharan ◽  
Subramanion L Jothy ◽  
Surash Ramanathan ◽  
Sharif M Mansor
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Staphylococcus Aureus ◽  
Transmission Electron Microscopy ◽  
Antimicrobial Activity ◽  
Methanol Extract ◽  
Elaeis Guineensis ◽  
Transmission Electron ◽  
Inhibition Concentration ◽  
Scanning Electron

Purpose: To evaluate the antimicrobial activity of the methanol extract of Elaeis guineensis leaf against Staphylococcus aureus and to determine the effect of extract treatment on the microstructure of the microbeMethods: The antimicrobial activity of the methanol leaf extract of the plant against S. aureus was examined using disc diffusion and broth dilution methods. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were carried out to determine the major alterations in the microstructure of S. aureus after treatment with the extract.Results: The extract showed a good antimicrobial activity against S. aureus with a minimum inhibition concentration (MIC) of 6.25 mg/mL and for Chloramphenicol was 30.00 ìg/mL. The main changes observed under SEM and TEM were structural disorganization of the cell membrane which occurred after 12 h and total collapse of the cell 36 h after exposure to the extract.Conclusion: We concluded that the methanolic extract of E. guineensis leaf exhibited good antimicrobial activity against S. aureus and this is supported by SEM and TEM.Keywords: Antimicrobial activity, Elaeis guineensis, Staphylococcus aureus, Scanning electron microscopy, Transmission electron microscopy

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