scholarly journals Novel magnetic organic–inorganic hybrids based on aromatic polyamides and ZnFe2O4 nanoparticles with biological activity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Reza Eivazzadeh-Keihan ◽  
Mostafa Ghafori Gorab ◽  
Hooman Aghamirza Moghim Aliabadi ◽  
Mohammad mahdavi ◽  
Ali Reza Akbarzadeh ◽  
...  
Keyword(s):  
Inhibitory Concentration ◽  
Aromatic Polyamide ◽  
Magnetic Core ◽  
Polymerization Process ◽  
Gram Negative Bacteria ◽  
Natural Polymers ◽  
Hemolytic Effect ◽  
Viability Percentage ◽  
First Time ◽  
Synthetic And Natural Polymers

AbstractMagnetic nanoparticles were creatively selected as stable, inexpensive, biodegradable, facile recoverable, and functionalizable supports for a variety of synthetic and natural polymers. Herein, for the first time, aromatic polyamide was synthesized on the magnetic core of zinc iron oxide (ZnFe2O4). Terephthaloyl chloride and derivations of phenylenediamine were employed as monomers in this polymerization process. The toxicity of the synthesized hybrid at the highest concentration (1000 μg/ml) is 13.65% and on the other hand, the cell viability percentage is 86.35%. So, the prepared hybrid is biocompatible and non-toxic to Hu02 cells. Also, it has antibacterial ability against gram-positive and gram-negative bacteria. Because the results show that the minimum inhibitory concentration (MIC) of the synthesized polymer for bacteria such as Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853 is in the range of 500–1000 µg/ml. Moreover, the hemolytic effect of ZnFe2O4 based hybrid was below 9% at the concentration of 1000 μg/ml. Therefore, it is compatible with red blood cells.

scholarly journals Antimicrobial and Antioxidant Activities of Plants from Northeast of Mexico

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Ricardo Salazar-Aranda ◽  
Luis Alejandro Pérez-López ◽  
Joel López-Arroyo ◽  
Blanca Alicia Alanís-Garza ◽  
Noemí Waksman de Torres
Keyword(s):  
Antioxidant Activity ◽  
Inhibitory Concentration ◽  
Antioxidant Activities ◽  
Scientific Information ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Time Activity ◽  
Gram Negative ◽  
Cyperus Alternifolius ◽  
First Time

Traditional medicine has a key role in health care worldwide. Obtaining scientific information about the efficacy and safety of the plants from our region is one of the goals of our research group. In this report, 17 plants were selected and collected in different localities from northeast Mexico. The dried plants were separated into leaves, flowers, fruit, stems, roots and bark. Each part was extracted with methanol, and 39 crude extracts were prepared. The extracts were tested for their antimicrobial activity using three Gram-negative bacterial strains (Pseudomonas aeruginosa,Klebsiella pneumoniaeandAcinetobacter baumannii), three Gram-positive bacterial strains (Enterococcus faecalisand twoStaphylococcus aureusstrains), and seven clinically isolated yeasts (Candida albicans,C. krusei,C. tropicalis,C. parapsilosisandC. glabrata); their antioxidant activity was tested using a DPPH free radical assay. No activity against Gram-negative bacteria was observed with any extract up to the maximum concentration tested, 1000 μg ml−1. We report here for the first time activity ofCeanothus coeruleusagainstS. aureus(flowers, minimal inhibitory concentration (MIC) 125 μg ml−1),C. glabrata(MICs 31.25 μg ml−1) andC. parapsilosis(MICs between 31.25 and 125 μg ml−1);Chrysanctinia mexicanaagainstC. glabrata(MICs 31.25μg ml−1);Colubrina greggiiagainstE. faecalis(MICs 250 μg ml−1) andCordia boissieriagainstC. glabrata(MIC 125μg ml−1). Furthermore, this is the first report about antioxidant activity of extracts fromCeanothus coeruleus,Chrysanctinia mexicana,Colubrina greggiiandCyperus alternifolius. Some correlation could exist between antioxidant activity and antiyeast activity against yeasts in the speciesCeanothus coeruleus,Schinus molle,Colubrina greggiiandCordia boissieri.

Effect of piperacillin on morphology and viability of gram-negative bacteria

1984 ◽  
Vol 42 ◽  
pp. 218-219
Author(s):  
R. H. Liss
Keyword(s):  
Inhibitory Concentration ◽  
Cytoplasmic Membrane ◽  
Drug Binding ◽  
Gram Negative Bacteria ◽  
Bacterial Cells ◽  
Drug Induced ◽  
Penicillin Binding Proteins ◽  
Lactam Antibiotic ◽  
Drug Free ◽  
Tube Dilution

Piperacillip (PIP) is b-[D(-)-α-(4-ethy1-2,3-dioxo-l-piperzinylcar-bonylamino)-α-phenylacetamido]-penicillanate. The broad spectrum semisynthetic β-lactam antibiotic is believed to effect bactericidal activity through its affinity for penicillin-binding proteins (PBPs), enzymes on the bacterial cytoplasmic membrane that control elongation and septation during cell growth and division. The purpose of this study was to correlate penetration and binding of 14C-PIP in bacterial cells with drug-induced lethal changes assessed by microscopic, microbiologic and biochemical methods.The bacteria used were clinical isolates of Escherichia coli and Pseudomonas aeruginosa (Figure 1). Sensitivity to the drug was determined by serial tube dilution in Trypticase Soy Broth (BBL) at an inoculum of 104 organisms/ml; the minimum inhibitory concentration of piperacillin for both bacteria was 1 μg/ml. To assess drug binding to PBPs, the bacteria were incubated with 14C-PIP (5 μg/0.09 μCi/ml); controls, in drug-free medium.

Antimicrobial and cytotoxic activity of Macrophomina phaseolina isolated from gummosis infected citrus reticulata

2013 ◽  
pp. 125-133
Author(s):  
Rubal C Das ◽  
Rajib Banik ◽  
Robiul Hasan Bhuiyan ◽  
Md Golam Kabir
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Brine Shrimp ◽  
Inhibitory Concentration ◽  
Lethal Dose ◽  
Macrophomina Phaseolina ◽  
Chloroform Extract ◽  
Citrus Reticulata ◽  
Gram Negative Bacteria ◽  
Gram Negative

Macrophomina phaseolina is one of the pathogenic organisms of gummosis disease of orange tree (Citrus reticulata). The pathogen was identified from the observation of their colony size, shape, colour, mycelium, conidiophore, conidia, hyaline, spore, and appressoria in the PDA culture. The crude chloroform extracts from the organism showed antibacterial activity against a number of Gram positive and Gram-negative bacteria. The crude chloroform extract also showed promising antifungal activity against three species of the genus Aspergillus. The minimum inhibitory concentration (MIC) of the crude chloroform extract from M. phaseolina against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Shigella sonnie were 128 ?gm, 256 ?gm, 128 ?gm and 64 ?gm/ml respectively. The LD50 (lethal dose) values of the cytotoxicity assay over brine shrimp of the crude chloroform extract from M. phaseolina was found to be 51.79 ?gm/ml. DOI: http://dx.doi.org/10.3329/cujbs.v5i1.13378 The Chittagong Univ. J. B. Sci.,Vol. 5(1 &2):125-133, 2010

scholarly journals The antimicrobial potential of cannabidiol

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Mark A. T. Blaskovich ◽  
Angela M. Kavanagh ◽  
Alysha G. Elliott ◽  
Bing Zhang ◽  
Soumya Ramu ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Modern Medicine ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
New Class ◽  
Clostridioides Difficile ◽  
Excellent Activity ◽  
Induce Resistance ◽  
First Time

AbstractAntimicrobial resistance threatens the viability of modern medicine, which is largely dependent on the successful prevention and treatment of bacterial infections. Unfortunately, there are few new therapeutics in the clinical pipeline, particularly for Gram-negative bacteria. We now present a detailed evaluation of the antimicrobial activity of cannabidiol, the main non-psychoactive component of cannabis. We confirm previous reports of Gram-positive activity and expand the breadth of pathogens tested, including highly resistant Staphylococcus aureus, Streptococcus pneumoniae, and Clostridioides difficile. Our results demonstrate that cannabidiol has excellent activity against biofilms, little propensity to induce resistance, and topical in vivo efficacy. Multiple mode-of-action studies point to membrane disruption as cannabidiol’s primary mechanism. More importantly, we now report for the first time that cannabidiol can selectively kill a subset of Gram-negative bacteria that includes the ‘urgent threat’ pathogen Neisseria gonorrhoeae. Structure-activity relationship studies demonstrate the potential to advance cannabidiol analogs as a much-needed new class of antibiotics.

scholarly journals Structure of the master regulator Rns reveals an inhibitor of enterotoxigenic Escherichia coli virulence regulons

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Charles R. Midgett ◽  
Kacey Marie Talbot ◽  
Jessica L. Day ◽  
George P. Munson ◽  
F. Jon Kull
Keyword(s):  
Escherichia Coli ◽  
Small Molecules ◽  
Family Member ◽  
Shigella Flexneri ◽  
Decanoic Acid ◽  
Enterotoxigenic Escherichia Coli ◽  
Gram Negative Bacteria ◽  
Enteric Infections ◽  
First Time ◽  
Arac Family

AbstractEnteric infections caused by the gram-negative bacteria enterotoxigenic Escherichia coli (ETEC), Vibrio cholerae, Shigella flexneri, and Salmonella enterica are among the most common and affect billions of people each year. These bacteria control expression of virulence factors using a network of transcriptional regulators, some of which are modulated by small molecules as has been shown for ToxT, an AraC family member from V. cholerae. In ETEC the expression of many types of adhesive pili is dependent upon the AraC family member Rns. We present here the 3 Å crystal structure of Rns and show it closely resembles ToxT. Rns crystallized as a dimer via an interface similar to that observed in other dimeric AraC’s. Furthermore, the structure of Rns revealed the presence of a ligand, decanoic acid, that inhibits its activity in a manner similar to the fatty acid mediated inhibition observed for ToxT and the S. enterica homologue HilD. Together, these results support our hypothesis that fatty acids regulate virulence controlling AraC family members in a common manner across a number of enteric pathogens. Furthermore, for the first time this work identifies a small molecule capable of inhibiting the ETEC Rns regulon, providing a basis for development of therapeutics against this deadly human pathogen.

scholarly journals Prevalence and Carbapenem Resistance of Acinetobacter baumannii and Other Than A. baumannii Isolates From Intensive Care Units (ICUs) and non-ICUs

2020 ◽  
Vol 41 (S1) ◽  
pp. s356-s357
Author(s):  
Tomasz Kasperski ◽  
Biophage Pharma S.A. Kraków ◽  
Agnieszka Chmielarczyk ◽  
Monika Pomorska-Wesolowska ◽  
Dorota Romaniszyn ◽  
...  
Keyword(s):  
Intensive Care ◽  
Inhibitory Concentration ◽  
Carbapenem Resistance ◽  
Diagnostic Methods ◽  
Clinical Settings ◽  
Gram Negative Bacteria ◽  
Carbapenem Resistant ◽  
Therapeutic Problem ◽  
Hospital Associated Infections ◽  
Very High

Background:Acinetobacter spp are gram-negative bacteria that have emerged as a leading cause of hospital-associated infections, most often in the intensive care unit (ICU) setting. This is particularly important in Poland, where the prevalence of A. baumannii in various types of infections, including bloodstream infection (BSI), pneumonia, skin and soft-tissue infection (SSTI), and urinary tract infection (UTI) is higher than in neighboring countries. Recently, other Acinetobacter spp, including A. lwoffii or A. ursingii, have been found to be clinically relevant. In Poland, we have also observed a very rapid increase in antimicrobial resistance, significantly faster for A. baumannii than for other nosocomial pathogens. Methods: A study was conducted in 12 southern Polish hospitals, including 3 ICUs, from January 1 to December 31, 2018. Only adult hospitalized patients were included. Strains were identified using the MALDI-TOF method. Carbapenem resistance was determined using the minimum inhibitory concentration (MIC). Results: During the study, 194 strains belonging to the Acinetobacter genus were isolated. A. baumannii was the dominant species, 88.1% (n = 171), and 23 isolates (11.9%) were other Acinetobacter spp: A. ursingii (n = 5), A. lwofii (n = 4), A. haemolyticus (n = 4), A. junii (n = 3), A. radioresistens (n = 2), A. bereziniae (n = 2), and A. johnsonii (n = 2). Moreover, 15 Acinetobacter strains were collected from ICUs. The most Acinetobacter strains were isolated from SSTIs (n = 115) from non-ICU settings. Non–A. baumannii strains were also most frequently isolated from SSTIs; they constituted 11.3% of all Acinetobacter strains from this type of infection (n = 13). The total Acinetobacter prevalence was 2.6%, whereas the prevalence in the ICU setting was 7%. Acinetobacter prevalence in SSTIs was 10.4%. In pneumonia, Acinetobacter prevalence was 18.6% for ICUs (n = 13) and 2.7% for non-ICUs (n = 46). Strains from UTIs were isolated only with the non-ICU setting, and their prevalence was 0.7% (n = 14). More than half of the tested strains (52.1%) were resistant to carbapenems, but all non–A. baumannii strains were susceptible. The highest resistance to carbapenems was among strains from pneumonia cases in ICUs (58.3%) and resistance among all strains isolated from ICU was 50%. However, even higher resistance was noted among SSTI strains from non-ICUs (61.7%). Conclusions: Increasingly, more than A. baumannii, other species among Acinetobacter strains are isolated from patients hospitalized in Polish hospitals. To assess the significance of non–A. baumannii spp in clinical settings, precise species identification is needed. Therefore, the diagnostic methods used must be improved. Carbapenem-resistant A. baumannii infections are the biggest problem in pneumonia patients in ICUs and in SSTI patients in other hospital departments. Carbapenem resistance occurs in a very high percentage of A. baumannii strains; among non–A. baumannii strains it is not yet a therapeutic problem.Funding: NoneDisclosures: None

Ultrastructural studies of Chlamydia psittaci 6BC variant strains. I. Ultrastructure of the surface layers of egg-passaged 6BC strain

1973 ◽  
Vol 19 (8) ◽  
pp. 887-894
Author(s):  
Linda Poffenroth ◽  
J. W. Costerton ◽  
Nonna Kordová ◽  
John C. Wilt
Keyword(s):  
Chick Embryo ◽  
Microscopic Examination ◽  
Electron Microscopic Examination ◽  
Chlamydia Psittaci ◽  
Gram Negative Bacteria ◽  
Surface Layers ◽  
Electron Microscopic ◽  
Gram Negative ◽  
Ultrastructural Studies ◽  
First Time

Electron microscopic examination of a semipurified Chlamydia psittaci 6BC strain attenuated in chick embryo yolk sac revealed for the first time two morphologically distinct small elementary bodies which differ both in the ultrastructure of their surface layers and in their buoyant densities in sucrose gradients. Also, the morphology of the surface layers of the larger reticulate forms in cell-free systems is described for the first time. Many points of difference between the surface envelopes and internal structure of chlamydial particles and those of Gram-negative bacteria are discussed.

scholarly journals Topographical and Biomechanical Guidance of Electrospun Fibers for Biomedical Applications

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2896
Author(s):  
Sara Ferraris ◽  
Silvia Spriano ◽  
Alessandro Calogero Scalia ◽  
Andrea Cochis ◽  
Lia Rimondini ◽  
...  
Keyword(s):  
Surface Modification ◽  
Biomedical Applications ◽  
Biomedical Application ◽  
Electrospun Fibers ◽  
Natural Polymers ◽  
Polymeric Fibers ◽  
Biological Phenomena ◽  
Proper Design ◽  
Synthetic And Natural Polymers ◽  
Selection Of

Electrospinning is gaining increasing interest in the biomedical field as an eco-friendly and economic technique for production of random and oriented polymeric fibers. The aim of this review was to give an overview of electrospinning potentialities in the production of fibers for biomedical applications with a focus on the possibility to combine biomechanical and topographical stimuli. In fact, selection of the polymer and the eventual surface modification of the fibers allow selection of the proper chemical/biological signal to be administered to the cells. Moreover, a proper design of fiber orientation, dimension, and topography can give the opportunity to drive cell growth also from a spatial standpoint. At this purpose, the review contains a first introduction on potentialities of electrospinning for the obtainment of random and oriented fibers both with synthetic and natural polymers. The biological phenomena which can be guided and promoted by fibers composition and topography are in depth investigated and discussed in the second section of the paper. Finally, the recent strategies developed in the scientific community for the realization of electrospun fibers and for their surface modification for biomedical application are presented and discussed in the last section.

scholarly journals Evaluation of antimicrobial activity of the endophytic actinomycete R18(6) against multiresistant Gram-negative bacteria

2016 ◽  
Vol 88 (1) ◽  
pp. 155-163 ◽  
Author(s):  
Tiele Carvalho ◽  
Sueli Van Der Sand
Keyword(s):  
Antimicrobial Activity ◽  
Inhibitory Concentration ◽  
Proteolytic Enzymes ◽  
Gram Negative Bacteria ◽  
Bacteriostatic Activity ◽  
Submerged Cultures ◽  
Gram Negative ◽  
Endophytic Actinomycete ◽  
Endophytic Actinomycetes ◽  
Antimicrobial Substances

Endophytic actinomycetes are promising sources of antimicrobial substances. This study evaluates the activity of metabolites produced by the endophytic actinomycete R18(6) against Gram-negative bacteria multiresistant to antimicrobials. R18(6) isolate was grown in submerged cultures under different conditions: carbon source, temperature, pH and incubation time to optimize antimicrobials production. The actinomycete grown in base medium supplemented with 1% glucose, pH 6.5 and incubation at 30 ºC for 96 h with shaking at 100 rpm, exhibited the highest activity against the used Gram-negative bacteria. Minimum inhibitory concentration (MIC) of the crude extract produced by the microorganism varied between 1/32 and 1/256. It had bactericide or bacteriostatic activity, depending on the Gram-negative organism. The active extract was stable at high temperatures, and unstable in medium containing proteolytic enzymes. Micromorphology of R18(6) was investigated by optical and scan microscopy, revealing that it was morphologically similar to the genusStreptomyces.

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