Dissociation of zinc phthalocyanine aggregation on bacterial surface is key for photodynamic antimicrobial effect

2018 ◽  
Vol 22 (09n10) ◽  
pp. 925-934 ◽  
Author(s):  
Dafeng Liu ◽  
Linsen Li ◽  
Jincan Chen ◽  
Zhuo Chen ◽  
Longguang Jiang ◽  
...  

Antimicrobial photodynamic therapy (aPDT) is an effective mean for killing bacteria in this era of increasing multi-antibiotic resistance, and possesses a number of unique advantages. Much effort has been devoted to the development a key component of aPDT photosensitizers (PSs). We synthesized a series of PSs with different positive charges (ZnPc(Lys)[Formula: see text], where [Formula: see text] 3, 5, 7, and studied their antibacterial activities and mechanisms against Escherichia coli (E. coli). Interestingly, the ZnPc(Lys)[Formula: see text] derivative showed stronger antibacterial effect (MIC = 25.3 [Formula: see text]M) than the other two PSs (MICs = 50.6 [Formula: see text]M), even though this PS did not have the highest uptake on bacteria among these PSs. It was ZnPc(Lys)[Formula: see text] that possessed the highest bacterial uptake. ZnPc(Lys)[Formula: see text] was found to have the highest monomeric fractions (62.0%) on bacteria surface than the other two PSs (37.9% for [Formula: see text] 3 and 33.9% [Formula: see text] = 7). These results clearly demonstrate that PS conformation on bacterial surface as a key parameter determining antibacterial efficacy of PSs. Other mechanistic aspects of photodynamic effects, including PS binding kinetics, bacterial surface hydrophobicity, zeta potential of bacteria, membrane permeability and bacterial signaling pathways were also studied.

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Marta Bregón-Villahoz ◽  
Maria-Dolores Moragues ◽  
Inés Arrieta-Aguirre ◽  
Mikel Azkargorta ◽  
Lucía Lainz ◽  
...  

Purpose. Some microbiota patterns have been associated with favorable IVF prognosis and others with pathological conditions. The endometrial fluid aspirate (EFA) contains antibacterial proteins that are enriched in implantative IVF cycles, but the antimicrobial effect of EFA has not been addressed. We aimed to evaluate the antimicrobial activity of the human endometrial fluid during the natural cycle. Methods. EFA was obtained through an embryo transfer catheter in 38 women, aged 18-40 years, with regular cycles attending to a fertility clinic. The antimicrobial activity of EFAs was tested against two strains of Staphylococcus aureus; one strain each of Streptococcus agalactiae, Enterococcus faecalis, Escherichia coli, and Klebsiella pneumoniae; and three yeasts (Candida albicans, Candida glabrata, and Candida krusei). Results. All samples exhibited antibacterial activity against S. aureus. In addition, 32.4% of EFAs were active against one of the other microorganisms assayed, 16.2% against two, and 5.4% against four of them. In contrast, none exhibited antibacterial activity against E. coli or K. pneumoniae. The antimicrobial activity differs considerably between EFA samples, and we failed to observe a cycle-related pattern. Conclusions. EFA presented two antimicrobial activity patterns: (a) one common to all the samples, exhibiting activity against S. aureus and lack of activity against E. coli and K. pneumoniae, and (b) an individualized pattern, showing activity against some of the other microorganisms tested. The intensity of antibacterial activity differs between EFA samples. Our data suggest that the uterine microbiota is controlled by means of endometrial fluid components.


2021 ◽  
Vol 2021 ◽  
pp. 1-5
Author(s):  
Frank Mayta-Tovalino ◽  
Alicia Fernández-Giusti ◽  
Joyce Del Pino ◽  
Daniel Alvitez-Temoche ◽  
Roman Mendoza ◽  
...  

Aim. To formulate and develop a new experimental polishing paste based on Coturnix coturnix eggshell and to evaluate its abrasive, remineralizing, and antibacterial activities. Materials and Methods. The research was experimental, longitudinal, comparative, and prospective. To measure the antibacterial efficacy, analysis units consisted of wells were made. The microorganisms S. aureus, E. coli, E. faecalis, C. albicans, and S. mutans were inoculated with experimental paste (Coturnix coturnix quail eggshell base) and control paste (Universal Polishing and Diamond Excel) consisting of n = 12 for each group. Results. It was found that, among the strains inoculated, the quail paste presented with the highest antimicrobial effectiveness to C. albicans and S. mutans with an average of 8.70 ± 0.14 and 11.65 ± 0.15 mm, respectively. On the other hand, the Universal Polishing paste only had an average of 7.00 ± 0.11 and 8.71 ± 0.11 mm for C. albicans and S. mutans, respectively. Significant differences were observed only in these two strains p < 0.001 . Conclusions. The quail paste demonstrated antimicrobial efficacy against C. albicans and S. mutans compared to control paste, Diamond Excel, and Universal Polishing according to the time and type of microorganism.


2022 ◽  
Author(s):  
Ehsan Aliakbari ◽  
Reza Eghdam Zamiri ◽  
Mehri Mahdavi ◽  
Vahid Yousefi

Abstract Due to the significance of drug delivery, the design of novel progressive nanomaterials for targeting drug delivery is a significant role in pharmacotherapy, as this method is supposed to reach a more exact target. One of the most distinguished materials by researchers is the poly ionic liquid (PIL), which have been used as anticancer drugs carriers and notably improve the antitumor effect and half-life. In this work, an efficient and stable nanocarrier containing silver nanoparticle, which were well distributed throughout the ionic liquid-based copolymer network (PILP-Ag), was reported for the drug delivery with antimicrobial effect. PILP was synthesized by radical silver nanoparticles was anchored into PIL voids by in-situ reduction, which enrich the adsorption capability of drug and antimicrobial effect of the nanocarrier. The synthesized nanomaterials were characterized by various techniques such as BET, TGA, SEM, TEM, AAS and FT-IR spectroscopy. The antibacterial activities of the silver-containing PIL against both S. aureus and E. coli were studied by determination of the minimum inhibitory concentration and Minimum Bactericidal Concentration.


2002 ◽  
Vol 65 (7) ◽  
pp. 1093-1099 ◽  
Author(s):  
DIKE O. UKUKU ◽  
WILLIAM F. FETT

The cantaloupe melon has been associated with outbreaks of Salmonella infections. It is suspected that bacterial surface charge and hydrophobicity may affect bacterial attachment and complicate bacterial detachment from cantaloupe surfaces. The surface charge and hydrophobicity of strains of Salmonella, Escherichia coli (O157:H7 and non-O157:H7), and Listeria monocytogenes were determined by electrostatic and hydrophobic interaction chromatography, respectively. Initial bacterial attachment to cantaloupe surfaces and the ability of bacteria to resist removal by washing with water were compared with surface charge and hydrophobicity. Whole cantaloupes were submerged in inocula containing individual strains or in cocktails containing Salmonella, E. coli, and L. monocytogenes, either as a mixture of strains containing all three genera or as a mixture of strains belonging to a single genus, for 10 min. Inoculated cantaloupes were dried for 1 h in a biosafety cabinet and then stored for up to 7 days at 4°C. Inoculated melons were washed with water, and bacteria still attached to the melon surface, as well as those in the wash water, were enumerated. Initial bacterial attachment was highest for individual strains of E. coli and lowest for L. monocytogenes, but Salmonella exhibited the strongest attachment on days 0, 3, and 7. When mixed-genus cocktails were used, the relative degrees of attachment of the three genera ware altered. The attachment of Salmonella strains was the strongest, but the attachment of E. coli was more extensive than that of L. monocytogenes on days 0, 3, and 7. There was a linear correlation between bacterial cell surface hydrophobicity (r2 = 0.767), negative charge (r2 = 0.738), and positive charge (r2 = 0.724) and the strength of bacterial attachment to cantaloupe surfaces.


1996 ◽  
Vol 40 (6) ◽  
pp. 1422-1425 ◽  
Author(s):  
R S Dykhuizen ◽  
R Frazer ◽  
C Duncan ◽  
C C Smith ◽  
M Golden ◽  
...  

Dietary intake of nitrate generates salivary nitrite, which is acidified in the stomach, leading to a number of reactive intermediates of nitrogen, among which are the potentially carcinogenic N-nitrosamines. Acidified nitrite, however, also has antimicrobial activity which coincides with the formation of nitric oxide. The present study examines the antimicrobial effect in vitro of acidified nitrite on Salmonella enteritidis, Salmonella typhimurium, Yersinia enterocolitica, Shigella sonnei, and Escherichia coli O157. First-order regression plots showed a linear inverse relationship of log-transformed proton and nitrite concentrations with MICs and MBCs after 30 min, 2 h, and 24 h of exposure (P < 0.001 for all antibacterial activities). Susceptibility to the acidified nitrate solutions ranked as follows: Y. enterocolitica > S. enteritidis > S. typhimurium = Shigella sonnei > E. coli O157 (P < 0.05). Addition of SCN-, but not that of CI-, increased the antibacterial activity (paired t testing, P < 0.001). Generation of salivary nitrite from dietary nitrate may provide significant protection against gut pathogens in humans.


1999 ◽  
Vol 43 (3) ◽  
pp. 454-459 ◽  
Author(s):  
William J. Weiss ◽  
Peter J. Petersen ◽  
Nilda V. Jacobus ◽  
Yang-I Lin ◽  
Panayota Bitha ◽  
...  

ABSTRACT CL 188,624, CL 190,294, and CL 191,121 are novel aminomethyl tetrahydrofuranyl (THF)-1β-methylcarbapenems. The in vitro antibacterial activities of these THF carbapenems were evaluated and compared with those of biapenem, imipenem, and meropenem against 554 recent clinical isolates obtained from geographically distinct medical centers across North America. The antibacterial activities of the THF carbapenems were equivalent to that of biapenem, and the THF carbapenems were slightly more active than imipenem and less active than meropenem against most of the members of the family Enterobacteriaceae but lacked significant activity against Pseudomonasisolates. In general, CL 191,121 was two- to fourfold more active than CL 188,624 and CL 190,294 against the staphylococcal and enterococcal isolates tested. CL 191,121 was twofold less active than imipenem against methicillin-susceptible staphylococci and was as activity as imipenem against Enterococcus faecalis isolates. Biapenem and meropenem were two- and fourfold less active than CL 191,121, respectively, against the methicillin-susceptible staphylococci andE. faecalis. All the carbapenems displayed equivalent good activities against the streptococci. Biapenem was slightly more active than the other carbapenems againstBacteroides fragilis isolates. Time-kill curve studies demonstrated that the THF carbapenems were bactericidal in 6 h against Escherichia coli andStaphylococcus aureus isolates. The postantibiotic effect exerted by CL 191,121 was comparable to or slightly longer than that of imipenem against isolates of S. aureus, E. coli, and Klebsiella pneumoniae.


Author(s):  
J.L. Carrascosa ◽  
G. Abella ◽  
S. Marco ◽  
M. Muyal ◽  
J.M. Carazo

Chaperonins are a class of proteins characterized by their role as morphogenetic factors. They trantsiently interact with the structural components of certain biological aggregates (viruses, enzymes etc), promoting their correct folding, assembly and, eventually transport. The groEL factor from E. coli is a conspicuous member of the chaperonins, as it promotes the assembly and morphogenesis of bacterial oligomers and/viral structures.We have studied groEL-like factors from two different bacteria:E. coli and B.subtilis. These factors share common morphological features , showing two different views: one is 6-fold, while the other shows 7 morphological units. There is also a correlation between the presence of a dominant 6-fold view and the fact of both bacteria been grown at low temperature (32°C), while the 7-fold is the main view at higher temperatures (42°C). As the two-dimensional projections of groEL were difficult to interprete, we studied their three-dimensional reconstruction by the random conical tilt series method from negatively stained particles.


2019 ◽  
Vol 10 ◽  
pp. 1864-1872
Author(s):  
Prof. Teodora P. Popova

The effect of ionized aqueous solutions (anolytes and catholyte) in the processing of fruits (cherries, morellos, and strawberries) for decontamination has been tested. Freshly prepared analytes and catholyte without the addition of salts were used, as well as stored for 7 months anolytes, prepared with 0.5% NaCl and a combination of 0.5% NaCl and 0.5% Na2CO3. The anolyte prepared with a combination of 0.5% NaCl and 0.5% Na2CO3, as well as the anolyte obtained with 0.5% NaCl, exhibit high antimicrobial activity against the surface microflora of strawberries, cherries, and sour cherries. They inactivate E. coli for 15 minutes. The other species of the fam. Enterobacteriaceae were also affected to the maximum extent, as is the total number of microorganisms, especially in cherries and sour cherries. Even stored for 7 months, they largely retain their antimicrobial properties. Anolyte and catholyte, obtained without the addition of salts, showed a lower effect on the total number of microorganisms, but had a significant effect on Gram-negative bacteria, and especially with regard to the sanitary indicative E. coli.


Author(s):  
Kyoung- Sun Seo ◽  
Seong Woo Jin ◽  
Seongkyu Choi ◽  
Kyeong Won Yun

The antibacterial activity of three Cupressaceae plants (Thujaoccidentalis,ThujaorientalisandChamaecyparisobtusa) was tested against three bacteria using the agar diffusion method. The ether and ethylacetate fraction of crude methanol extract from the three plants showed potent antibacterial activity against the tested microorganisms. The result showed that Staphylococcus aureus revealed the most sensitivity among the tested bacteria. Thujaoccidentalisether fraction and Thujaorientalis hexane fraction exhibited the highest antibacterial activity against Staphylococcus aureus. E. coli was shown the highest MIC values compared to the other two tested bacteria, which indicates the lowest antibacterial activity against the bacterium. This study promises an interesting future for designing a potentially active antibacterial agent from the three Cupressaceae plants.


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