Study on the Bactriostasis of Nano-Silver against Four Strains of Bacteria

2014 ◽  
Vol 1051 ◽  
pp. 3-11 ◽  
Author(s):  
Lu Qiu ◽  
Hai Han Yang ◽  
Jia Yan Lv ◽  
Shu Guo Fan ◽  
Mei Hua Xie ◽  
...  

Through a comparative study of the bacteriostatic effect of nanosilver of different species and concentrations against bacteria, it is found that nanosilver have significant bacteriostatic effect against bacteria. Bateriostatic effect of nanosilve 15# against B. thuringiensis is significantly better than E.coli, s. aureus and B. subtillis. The optimal concentrations of 15# for inhabiting E. coli, S. aureus, B. subtillis and B. thuringiensis respectively are: 20 mg/L, 10 mg/L, 1 mg/L, 40 mg/L. nanosilvers of 13#, 14# and 15# have no significant differences in the bacteriostatic effect against E.coli, but are all significantly better than the bacteriostats of lincomycin hydrochloride and streptomycin sulfate. Antibacterial principle of nanosilver is damaging the cell membrane permeability.

2014 ◽  
Vol 1051 ◽  
pp. 62-69
Author(s):  
Lu Qiu ◽  
Mei Hua Xie ◽  
Jia Yan Lv ◽  
Shu Guo Fan ◽  
Jian Hui Gao

15# nanosilvehas significantly bateriostatic effect against Penicillium, The minimal inhibitory concentrations of 15# nana silve for inhabiting Penicillium is 1 mg/L. Through a comparative study of the bacteriostatic effect of different nanosilver and other bacteriostatic agents against Penicillium, it is found that the bacteriostatic effect of nanosilver against penicillium is very significantly better than lincomycin hydrochloride and streptomycin sulfate, in which, the bacteriostatic effect of nanosilver 14# nanosilve against penicillium is significantly better than 13# nanosilve, and 13# nanosilve is very significantly better than that of 15# nanosilve.It provides a new way for the prevention and control of Penicillium.


2014 ◽  
Vol 77 (10) ◽  
pp. 1740-1746 ◽  
Author(s):  
WEN-RUI DIAO ◽  
LIANG-LIANG ZHANG ◽  
SAI-SAI FENG ◽  
JIAN-GUO XU

Amomum kravanh is widely cultivated and used as a culinary spice. In this work, the chemical composition of the essential oil obtained by hydrodistillation of A. kravanh fruits was analyzed by gas chromatography–mass spectrometry, and 34 components were identified. 1,8-Cineole (68.42%) was found to be the major component, followed by α-pinene (5.71%), α-terpinene (2.63%), and β-pinene (2.41%). The results of antibacterial tests showed that the sensitivities to the essential oil of different foodborne pathogens tested were different based on the Oxford cup method, MIC, and MBC assays, and the essential oil exhibited the best antibacterial activity against Bacillus subtilis, a gram-positive bacterium, and Escherichia coli, a gram-negative bacterium. Growth in the presence of Amomum kravanh at the MIC, as measured by monitoring optical density over time, demonstrated that the essential oil was bacteriostatic after 12 h to both B. subtilis and E. coli. Observations of cell membrane permeability, cell constituent release assay, and transmission electron microscopy indicated that this essential oil may disrupt the cell wall and cell membrane permeability, leading to leakage of intracellular constituents in both B. subtilis and E. coli.


2008 ◽  
Vol 74 (16) ◽  
pp. 5015-5022 ◽  
Author(s):  
Haiqing Sheng ◽  
Ji Youn Lim ◽  
Maryann K. Watkins ◽  
Scott A. Minnich ◽  
Carolyn J. Hovde

ABSTRACT Escherichia coli O157:H7 causes hemorrhagic colitis and the life-threatening hemolytic-uremic syndrome in humans and transiently colonizes healthy cattle at the terminal rectal mucosa. To investigate the role of the O antigen in persistence and colonization in the animal host, we generated an E. coli O157:H7 mutant defective in the synthesis of the lipopolysaccharide side chain (O antigen) by deletion of a putative perosamine synthetase gene (per) in the rfb cluster. The lack of O antigen was confirmed by using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and anti-O157 antibody. The growth rate and cell membrane permeability of the Δper mutant were similar to the growth rate and cell membrane permeability of the wild type. Changes in membrane and secreted proteins were observed, but the expression of intimin, EspA, and EspB, implicated in bacterial intestinal colonization, was not altered, as determined by immunoblotting and reverse transcription-PCR. Similar to other O-antigen deletion mutants, the Δper mutant was pleiotropic for autoaggregation and motility (it was FliC negative as determined by immunoblotting and flagellum negative as determined by electron microscopy). The abilities of the mutant and the wild type to persist in the murine intestine and to colonize the bovine terminal rectal mucosa were compared. Mice fed the Δper mutant shed lower numbers of bacteria (P < 0.05) over a shorter time than mice fed the wild-type or complemented strain. After rectal application in steers, lower numbers of the Δper mutant than of the wild type colonized the rectoanal junction mucosa, and the duration of the colonization was shorter (P < 0.05). Our previous work showed that flagella do not influence E. coli O157:H7 colonization at the bovine terminal rectal mucosa, so the current findings suggest that the O antigen contributes to efficient bovine colonization.


Author(s):  
M. Ashraf ◽  
L. Landa ◽  
L. Nimmo ◽  
C. M. Bloor

Following coronary artery occlusion, the myocardial cells lose intracellular enzymes that appear in the serum 3 hrs later. By this time the cells in the ischemic zone have already undergone irreversible changes, and the cell membrane permeability is variably altered in the ischemic cells. At certain stages or intervals the cell membrane changes, allowing release of cytoplasmic enzymes. To correlate the changes in cell membrane permeability with the enzyme release, we used colloidal lanthanum (La+++) as a histological permeability marker in the isolated perfused hearts. The hearts removed from sprague-Dawley rats were perfused with standard Krebs-Henseleit medium gassed with 95% O2 + 5% CO2. The hypoxic medium contained mannitol instead of dextrose and was bubbled with 95% N2 + 5% CO2. The final osmolarity of the medium was 295 M osmol, pH 7. 4.


2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Chunlan Shan ◽  
Shushu Miao ◽  
Chaoying Liu ◽  
Bo Zhang ◽  
Weiwei Zhao ◽  
...  

Abstract Background Pyroptosis plays a pivotal role in the pathogenesis of many inflammatory diseases. The molecular mechanism by which pyroptosis is induced in macrophages following infection with pathogenic E. coli high pathogenicity island (HPI) will be evaluated in our study. Results After infection with the HPI+/HPI− strains and LPS, decreased macrophage cell membrane permeability and integrity were demonstrated with propidium iodide (PI) staining and the lactate dehydrogenase (LDH) assay. HPI+/HPI−-infection was accompanied by upregulated expression levels of NLRP3, ASC, caspase-1, IL-1β, IL-18 and GSDMD, with significantly higher levels detected in the HPI+ group compared to those in the HPI− group (P < 0.01 or P < 0.05). HPI+ strain is more pathogenic than HPI− strain. Conclusion Our findings indicate that pathogenic E. coli HPI infection of Saba pigs causes pyroptosis of macrophages characterized by upregulated expression of pyroptosis key factors in the NLRP3/ASC/caspase-1 signaling pathway, direct cell membrane pore formation, and secretion of the inflammatory factor IL-1β and IL-18 downstream of NLRP3 and caspase-1 activation to enhance the inflammatory response.


2015 ◽  
Vol 25 (17) ◽  
pp. 3610-3615 ◽  
Author(s):  
Junsuke Hayashi ◽  
Tomoko Hamada ◽  
Ikumi Sasaki ◽  
Osamu Nakagawa ◽  
Shun-ichi Wada ◽  
...  

1974 ◽  
Vol 64 (6) ◽  
pp. 706-729 ◽  
Author(s):  
W. R. Redwood ◽  
E. Rall ◽  
W. Perl

The permeability coefficients of dog red cell membrane to tritiated water and to a series of[14C]amides have been deduced from bulk diffusion measurements through a "tissue" composed of packed red cells. Red cells were packed by centrifugation inside polyethylene tubing. The red cell column was pulsed at one end with radiolabeled solute and diffusion was allowed to proceed for several hours. The distribution of radioactivity along the red cell column was measured by sequential slicing and counting, and the diffusion coefficient was determined by a simple plotting technique, assuming a one-dimensional diffusional model. In order to derive the red cell membrane permeability coefficient from the bulk diffusion coefficient, the red cells were assumed to be packed in a regular manner approximating closely spaced parallelopipeds. The local steady-state diffusional flux was idealized as a one-dimensional intracellular pathway in parallel with a one-dimensional extracellular pathway with solute exchange occurring within the series pathway and between the pathways. The diffusion coefficients in the intracellular and extracellular pathways were estimated from bulk diffusion measurements through concentrated hemoglobin solutions and plasma, respectively; while the volume of the extracellular pathway was determined using radiolabeled sucrose. The membrane permeability coefficients were in satisfactory agreement with the data of Sha'afi, R. I., C. M. Gary-Bobo, and A. K. Solomon (1971. J. Gen. Physiol. 58:238) obtained by a rapid-reaction technique. The method is simple and particularly well suited for rapidly permeating solutes.


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