scholarly journals Microbubble-Mediated Ultrasound Enhances the Lethal Effect of Gentamicin on PlanktonicEscherichia coli

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Han-Xiao Zhu ◽  
Xun-Zi Cai ◽  
Zhong-Li Shi ◽  
Bin Hu ◽  
Shi-Gui Yan
Keyword(s):  
Cell Membranes ◽  
Inhibitory Concentration ◽  
Acoustic Cavitation ◽  
Lethal Effect ◽  
Average Intensity ◽  
E Coli ◽  
Low Intensity ◽  
Transmission Electron ◽  
Low Intensity Ultrasound ◽  
Number Of Bacteria

Previous research has found that low-intensity ultrasound enhanced the lethal effect of gentamicin on planktonicE. coli. We aimed to further investigate whether microbubble-mediated low-intensity ultrasound could further enhance the antimicrobial efficacy of gentamicin. The planktonicE. coli(ATCC 25922) was distributed to four different interventions: control (GCON), microbubble only (GMB), ultrasound only (GUS), and microbubble-mediated ultrasound (GMUS). Ultrasound was applied with 100 mW/cm2(average intensity) and 46.5 KHz, which presented no bactericidal activity. After 12 h, plate counting was used to estimate the number of bacteria, and bacterial micromorphology was observed with transmission electron microscope. The results showed that the viable counts ofE. coliinGMUSwere decreased by 1.01 to 1.42 log10 CFU/mL compared withGUS(P<0.01). The minimal inhibitory concentration (MIC) of gentamicin againstE. coliwas 1 μg/mL in theGMUSandGUSgroups, lower than that in theGCONandGMBgroups (2 μg/mL). Transmission electron microscopy (TEM) images exhibited more destruction and higher thickness of bacterial cell membranes in theGMUSthan those in other groups. The reason might be the increased permeability of cell membranes for gentamicin caused by acoustic cavitation.

scholarly journals New Bacteriocins from Lacticaseibacillus paracasei CNCM I-5369 Adsorbed on Alginate Nanoparticles Are Very Active against Escherichia coli

2020 ◽  
Vol 21 (22) ◽  
pp. 8654
Author(s):  
Yanath Belguesmia ◽  
Noura Hazime ◽  
Isabelle Kempf ◽  
Rabah Boukherroub ◽  
Djamel Drider
Keyword(s):  
Escherichia Coli ◽  
High Performance ◽  
Hplc Analysis ◽  
Inhibitory Concentration ◽  
Culture Supernatant ◽  
Gram Negative Bacteria ◽  
E Coli ◽  
Highly Active ◽  
Transmission Electron ◽  
Intracellular Proteins

Lacticaseibacillus paracasei CNCM I-5369, formerly Lactobacillus paracasei CNCM I-5369, produces bacteriocins that are remarkably active against Gram-negative bacteria, among which is the Escherichia coli-carrying mcr-1 gene that is involved in resistance to colistin. These bacteriocins present in the culture supernatant of the producing strain were extracted and semi-purified. The fraction containing these active bacteriocins was designated as E20. Further, E20 was loaded onto alginate nanoparticles (Alg NPs), leading to a highly active nano-antibiotics formulation named hereafter Alg NPs/E20. The amount of E20 adsorbed on the alginate nanoparticles was 12 wt.%, according to high-performance liquid chromatography (HPLC) analysis. The minimal inhibitory concentration (MIC) values obtained with E20 ranged from 250 to 2000 μg/mL, whilst those recorded for Alg NPs/E20 were comprised between 2 and 4 μg/mL, which allowed them to gain up to 500-fold in the anti-E. coli activity. The damages caused by E20 and/or Alg NPs/E20 on the cytology of the target bacteria were characterized by transmission electron microscopy (TEM) imaging and the quantification of intracellular proteins released following treatment of the target bacteria with these antimicrobials. Thus, loading these bacteriocins on Alg NPs appeared to improve their activity, and the resulting nano-antibiotics stand as a promising drug delivery system.

Study on Effect of Low Frequency and Low Intensity Ultrasound on Leukemic Cell Lines K562 and Human Hematopoietic Cells.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4420-4420
Author(s):  
Bao-An Chen ◽  
Yan Ma ◽  
Chong Gao ◽  
Jia-Hua Ding ◽  
Yun-Yu Sun ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Cell Lines ◽  
Exposure Time ◽  
Transmission Electron Microscope ◽  
Caspase 3 ◽  
Hematopoietic Cells ◽  
Low Frequency ◽  
Low Intensity ◽  
Transmission Electron ◽  
Low Intensity Ultrasound

Abstract Objective: To investigate the effect of low frequency and low intensity ultrasound on leukemia cell lines K562 and to clarify the role of Caspase-3 in the effect and to study the effect of low frequency and low intensity ultrasound on human hematopoietic cells. Methods: K562 cells in log phase were divided into 2 groups: control group and experimental group. The tensity of low frequency(20kHz) and low intensity ultrasound were 0.03W/m2 0.1W/m2 and 0.25W/m2 respectively. The exposure time were 30s and 60s respectively. K562 cells were incubated in 24-well culture plates for different time periods (6h,24h,48h) after sonication and the number of vital cells was tested by MTT assay. The morphology of apoptosis were analyzed by Wright’s stain and transmission electron microscope. The pencentage of apoptosis were studied by flow cytometry (FCM). The activation of Caspase-3 were tested by Caspase-3 kit with spectrophotometric method. All the hematopoietic cells were classified to two groups: control and experimental groups. The intensity of low frequency(20kHz) and low intensity ultrasound were 0.03W/m2 0.1W/m2 and 0.25W/m2 respectively. The exposure time were 30s and 60s respectively. The cells were incubated in 24-well culture plates for different time periods (6h, 24h, 48h) after sonication and the number of vital cells were tested by typhan blue exclusion. The ratio of apoptosis and morphology of apoptosis were analyzed by FCM, Wright’s stain and transmission electron microscope. Results: The absorbance value of MTT decreased significantly after exposure. The highest apoptosis was found in 0.25W group after 30-s sonication and 6-h incubation. Morphological alterations observed in cells after exposure to ultrasound included: cell shrinkage, membrane blebbing, chromatin condensation, nuclear fragmentation, and apoptotic body formation. The result of FCM included: control 7.6%; 0.03W,30s,6h 11.57%; 0.1W,30s,6h 35.95%;0.25W,30s,6h 38.87%. There were no significant difference of activation of Caspase-3 between control and experimental group(0.25W group after 30-s sonication and 6-h incubation). The result of typhan blue exclusion was: the difference between each group was not significant. FCM, Wright’s stain and transmission electron microscope did not find apoptosis in each group. Conclusions: Low frequency and low intensity ultrasound can induce apoptosis in K562 cell lines after exposure. The effect went significantly when the intensity of ultrasound increase, without relation to the exposure time. The low frequency and low intensity ultrasound has no significant effect on human hematopoietic cells.

Hepatocellular carcinoma cell apoptosis induced by low-intensity ultrasound with polylactic acid-polyethylene glycol nanometer microspheres loaded with sodium cantharidin: An in vitro study

2020 ◽  
Vol 10 (6) ◽  
pp. 883-891
Author(s):  
Ting Luo ◽  
Kaiyuan Zhang ◽  
Luyan Zhao ◽  
Tianlin Su ◽  
Bingshe Yang
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Cycle ◽  
Intracellular Calcium ◽  
Hepg2 Cells ◽  
Calcium Concentration ◽  
Combination Group ◽  
Inhibition Rate ◽  
Low Intensity ◽  
Transmission Electron ◽  
Low Intensity Ultrasound

This study examines the synergistic inhibitory effect of two drugs on hepatocellular carcinoma cells using polylactic acid-polyethylene glycol (PLA-PEG) nanoparticles loaded with sodium cantharidin (SCA) combined with low-intensity ultrasound. We sought to provide an experimental basis for the cytological level of SCA combined with low-intensity ultrasound tumor treatment. The study consisted of four treatment groups: HepG2 cells treated with 2.5 g/mL SCA for 30 min then irradiated with 0.5 w/cm2 low-intensity ultrasound for 8 s (combination group), HepG2 cells treated with SCA alone (SCA group), HepG2 cells randomly irradiated with low-intensity ultrasound (ultrasound group), and HepG2 cells without intervention (control group). After each treatment, the cells were cultured for 6 h, and then the cell proliferation inhibition rate, apoptosis cycle, and intracellular calcium concentration were detected using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry and Fluo-3 AM detection. Intracellular ultrastructural changes were observed using transmission electron microscopy. The results showed that the proliferation inhibition rate of cells in the combination group was significantly higher than that in the SCA and ultrasound groups. Annexin V-FITC and propidium iodide staining revealed that the apoptosis rate of the combination group significantly increased compared with that of the other groups. There was no significant difference in cell cycle among the different treatments after 6 h of cell culture. However, cell cycle arrest occurred in HepG2 cells at G0/G1 stage after 12 h of cell culture. Fluo-3 AM showed that the intracellular calcium concentration in the combined group was significantly higher than that in the other groups at 6 h after treatment. Transmission electron microscopy showed that apoptotic bodies and mitochondrial and endoplasmic reticulum swelling were present in the combined group after treatment. We conclude that low-intensity ultrasound (0.5 w/cm2) combined with SCA (2.5 μg/mL) synergistically induce apoptosis of hepatocellular carcinoma HepG2 cells, block cell cycle at G0/G1 phase, and disrupt intracellular calcium homeostasis. PLA-PEG can be loaded with SCA to improve drug targeting and drug concentration in the affected area.

scholarly journals Innovative Perspectives on Biofilm Interactions in Poultry Drinking Water Systems and Veterinary Antibiotics Used Worldwide

Antibiotics ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 77
Author(s):  
Friederike Hahne ◽  
Simon Jensch ◽  
Gerd Hamscher ◽  
Jessica Meißner ◽  
Manfred Kietzmann ◽  
...  
Keyword(s):  
Drinking Water ◽  
Inhibitory Concentration ◽  
Exposure Period ◽  
Antibiotic Use ◽  
Coli Strain ◽  
Veterinary Antibiotics ◽  
E Coli ◽  
Effective Evaluation ◽  
Veterinary Antibiotic ◽  
Number Of Bacteria

Prudent use of antibiotics in livestock is widely considered to be important to prevent antibiotic resistance. This study aimed to evaluate the interactions between biofilms and veterinary antibiotics in therapeutic concentrations administrated via drinking water through a standardized experimental setup. In this context, two biofilms formed by pseudomonads (Pseudomonas (P.) aeruginosa or P. fluorescens) and a susceptible Escherichia (E.) coli strain were developed in a nutrient-poor medium on the inner surface of polyvinyl chloride pipe pieces. Subsequently, developing biofilms were exposed to sulfadiazine/trimethoprim (SDZ/TMP) or tylosin A (TYL A) in dosages recommended for application in drinking water for 5 or 7 days, respectively. Various interactions were detected between biofilms and antibiotics. Microbiological examinations revealed that only TYL A reduced the number of bacteria on the surface of the pipes. Additionally, susceptible E. coli survived both antibiotic treatments without observable changes in the minimum inhibitory concentration to 13 relevant antibiotics. Furthermore, as demonstrated by HPLC-UV, the dynamics of SDZ/TMP and TYL A in liquid media differed between the biofilms of both pseudomonads over the exposure period. We conclude that this approach represents an innovative step toward the effective evaluation of safe veterinary antibiotic use.

An Ultrastructural Study of Chronic Pyelonephritis in Macaca Arctoides

1976 ◽  
Vol 34 ◽  
pp. 310-311
Author(s):  
T.W. Smith ◽  
J.A. Roberts ◽  
B.J. Martin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ultrastructural Study ◽  
Effective Means ◽  
Chronic Pyelonephritis ◽  
Macaca Arctoides ◽  
Left Ureter ◽  
E Coli ◽  
Transmission Electron ◽  
Sizeable Number

Chronic pyelonephritis is one of the most common diseases of the kidney and accounts for a sizeable number of cases of renal insufficiency in man, however its pathogenesis requires further elucidation. Transmission electron microscopy may serve as a uniquely effective means of observing details of the nature of this disease. The present paper describes preliminary results of an ultrastructural study of chronic pyelonephritis in Macaca arctoides (stumptail monkey).The infection was induced in these experiments in a retrograde fashion by means of a unilateral catheterization of the left ureter whereby an innoculum of 10 cc of broth containing approximately 2 billion E. coli per cc and radio-opaque dye were injected under pressure (mimicing vesico-ureteric reflux).

Imaging sub-micron objects with light microscopy: Visualization of the T-4 bacteriophage

1989 ◽  
Vol 47 ◽  
pp. 834-835
Author(s):  
Malcolm Brown ◽  
Reynolds M. Delgado ◽  
Michael J. Fink
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Focal Plane ◽  
Phase Contrast ◽  
Dark Field ◽  
E Coli ◽  
Polystyrene Beads ◽  
Television Camera ◽  
Transmission Electron ◽  
Universal Microscope

While light microscopy has been used to image sub-micron objects, numerous problems with diffraction-limitations often preclude extraction of useful information. Using conventional dark-field and phase contrast light microscopy coupled with image processing, we have studied the following objects: (a) polystyrene beads (88nm, 264nm, and 557mn); (b) frustules of the diatom, Pleurosigma angulatum, and the T-4 bacteriophage attached to its host, E. coli or free in the medium. Equivalent images of the same areas of polystyrene beads and T-4 bacteriophages were produced using transmission electron microscopy.For light microscopy, we used a Zeiss universal microscope. For phase contrast observations a 100X Neofluar objective (N.A.=1.3) was applied. With dark-field, a 100X planachromat objective (N.A.=1.25) in combination with an ultra-condenser (N.A.=1.25) was employed. An intermediate magnifier (Optivar) was available to conveniently give magnification settings of 1.25, 1.6, and 2.0. The image was projected onto the back focal plane of a film or television camera with a Carl Zeiss Jena 18X Compens ocular.

In Vitro Antibacterial activity of ethanolic extract of Myrsine africana against laboratory Strains of Pathogenic Organisms

2016 ◽  
Vol 5 (04) ◽  
pp. 4512
Author(s):  
Jackie K. Obey ◽  
Anthoney Swamy T* ◽  
Lasiti Timothy ◽  
Makani Rachel
Keyword(s):  
Antibacterial Activity ◽  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Ethanolic Extract ◽  
Ethanol Extract ◽  
E Coli ◽  
Zones Of Inhibition ◽  
In Vitro Antibacterial Activity ◽  
Myrsine Africana

The determination of the antibacterial activity (zone of inhibition) and minimum inhibitory concentration of medicinal plants a crucial step in drug development. In this study, the antibacterial activity and minimum inhibitory concentration of the ethanol extract of Myrsine africana were determined for Escherichia coli, Bacillus cereus, Staphylococcus epidermidis and Streptococcus pneumoniae. The zones of inhibition (mm±S.E) of 500mg/ml of M. africana ethanol extract were 22.00± 0.00 for E. coli,20.33 ±0.33 for B. cereus,25.00± 0.00 for S. epidermidis and 18. 17±0.17 for S. pneumoniae. The minimum inhibitory concentration(MIC) is the minimum dose required to inhibit growth a microorganism. Upon further double dilution of the 500mg/ml of M. africana extract, MIC was obtained for each organism. The MIC for E. coli, B. cereus, S. epidermidis and S. pneumoniae were 7.81mg/ml, 7.81mg/ml, 15.63mg/ml and 15.63mg/ml respectively. Crude extracts are considered active when they inhibit microorganisms with zones of inhibition of 8mm and above. Therefore, this study has shown that the ethanol extract of M. africana can control the growth of the four organisms tested.

Low-intensity ultrasound to induce proliferation and collagen Ι expression of adipose-derived mesenchymal stem cells and fibroblast cells in co-culture

Measurement ◽  
2021 ◽  
Vol 167 ◽  
pp. 108280
Author(s):  
Zeinab Hormozi-Moghaddam ◽  
Manijhe Mokhtari-Dizaji ◽  
Mohammad-Ali Nilforoshzadeh ◽  
Mohsen Bakhshandeh
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Fibroblast Cells ◽  
Low Intensity ◽  
Low Intensity Ultrasound
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