scholarly journals Conjugated polymer nanostructures displaying high photoactivated antimicrobial and antibiofilm functionalities

2021 ◽  
Author(s):  
Srabanti Ghosh ◽  
Marta Elena Gonzalez Mosquera ◽  
Georgiana Amariei ◽  
Roberto Rosal
Keyword(s):  
Conjugated Polymer ◽  
Antimicrobial Compounds ◽  
Gram Positive ◽  
Gram Negative ◽  
Polymer Nanostructures

This work report the use of conjugated polymer nanostructures (CPNs) as photoactivated antimicrobial compounds against gram-positive and gram-negative microorganisms. Two representative CPNs of polythiophene (PEDOT) and polyaniline (PANI) were prepared...

scholarly journals Correlation between the Antimicrobial Activity and Metabolic Profiles of Cell Free Supernatants and Membrane Vesicles Produced by Lactobacillus reuteri DSM 17938

2020 ◽  
Vol 8 (11) ◽  
pp. 1653
Author(s):  
Alessandro Maccelli ◽  
Simone Carradori ◽  
Valentina Puca ◽  
Francesca Sisto ◽  
Paola Lanuti ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Lactobacillus Reuteri ◽  
Membrane Vesicles ◽  
Metabolic Profiles ◽  
Ion Cyclotron Resonance ◽  
Antimicrobial Compounds ◽  
Ionization Source ◽  
Gram Positive ◽  
Gram Negative ◽  
Broth Microdilution Method

The aim of the work is to assess the antimicrobial activities of Cell Free Supernatants (CFS) and Membrane Vesicles (MVs), produced by Lactobacillus reuteri DSM 17938, versus Gram-positive and Gram-negative bacteria and investigate their metabolic profiles. The Minimum Inhibitory Concentration was determined through the broth microdilution method and cell proliferation assay while the Minimum Bactericidal Concentration was determined by Colony Forming Units counts. The characteristics of the antimicrobial compounds were evaluated by pH adjustments, proteinase treatment, and size fractionation of the CFS. The cytotoxicity of CFS was tested on two human cell lines. A detailed snapshot of the L. reuteri metabolism was attained through an untargeted metabolic profiling by means of high resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) coupled with Electrospray Ionization Source (ESI). The results showed (i) a greater efficacy of CFS and its fractions towards Gram-negative compared to Gram-positive bacteria; (ii) an antimicrobial effect related to pH-dependent compounds but not to MVs; (iii) a molecular weight < 3 KDa as well as an a non-proteinaceous nature of the antimicrobial compounds; and (iv) more than 200 and 500 putative metabolites annotated in MVs and supernatants, covering several classes of metabolites, including amino acids, lipids, fatty and organic acids, polyalcohols, nucleotides, and vitamins. Some putative compounds were proposed not only as characteristic of specific fractions, but also possibly involved in antimicrobial activity.

scholarly journals Chemical Profiling of Antimicrobial Metabolites from Halophilic Actinomycete Nocardiopsis_sp. Al-H10-1 (KF384482) Isolated from Alang, Gulf of Khambhat, India

2021 ◽  
Author(s):  
Jignasha T. Thumar ◽  
Nisha Trivedi
Keyword(s):  
Drug Resistance ◽  
Saline Water ◽  
Multiple Drug Resistance ◽  
World Health ◽  
Multiple Drug ◽  
Gram Negative Bacteria ◽  
Antimicrobial Compounds ◽  
Gram Positive ◽  
Gram Negative ◽  
Halophilic Actinomycete

The overuse of antibiotics has resulted in the development of drug resistant, a major problem in disease curing processes i.e. development of drug resistance. The World Health Organization (WHO) released its first list of the most concerning pathogens for human health in 2017 which suggested that there are total 12 bacterial families which have developed multiple drug resistance and for which novel antibiotics are required immediately (WHO 2017). There is a requirement to explore some novel compounds to overcome this issue. Thus our study aimed at exploration of marine actinomycetes as a valuable resource for novel products with antimicrobial properties. The halophilic actinomycete Nocardiopsis_sp. Al-H10-1 (KF384482) was isolated from saline water (20 m away from shore) of Alang coast (Gulf of Khambhat), Bhavnagar, Gujarat, India. The isolate Al-H10-1 was identified as Nocardiopsis sp. through rigorous morphological and cultural characteristics; the species was confirmed through 16s rRNA phylogenetic analysis. The antimicrobial potential of Nocardiopsis sp. Al-H10-1 was assessed against a range of Gram-positive and Gram-negative bacteria as well as three fungi, there it demonstrated antimicrobial activity against four Gram negative bacteria and one Gram positive bacteria. Further active antimicrobial compounds present in ethyl acetate extract was identified using Gas Chromatography-Mass Spectroscopy (GC-MS). GC-MS analysis showed the presence of 17 compounds which included antimicrobial compounds like 2, 4-bis (1, 1-dimethylethyl)-Phenol, Dibutyl phthalate as well as various types of alkanes and their derivatives.

scholarly journals Antimicrobial activity of ethanolic and aqueous extracts of medicinally used tree ferns Alsophila cuspidata and Cyathea microdonta

2018 ◽  
Vol 42 (1) ◽  
pp. 119-123
Author(s):  
Charlie Longtine ◽  
Adrian Tejedor
Keyword(s):  
Antimicrobial Activity ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Aqueous Extracts ◽  
Antimicrobial Compounds ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Neotropical Tree ◽  
Tree Ferns

Medicinal plants are important components of traditional medicine and sources of novel antimicrobial compounds against drug resistance pathogen strains. This study tested the antimicrobial activity of ethanolic and aqueous extracts of medicinally used Neotropical tree ferns Cyathea microdonta and Alsophila cuspidata against gram positive bacteria and gram negative bacteria using the Kirby-Bauer disc diffusion method. Highest antimicrobial activity was observed in ethanolic extracts, and extracts were more active against gram positive bacteria than gram negative bacteria. No difference was observed in antimicrobial activity between species or between extracts made from the leaves, stipe, or caudex. These results suggest that the traditional use of tree fern mucilage as a topical agent for cuts and leishmaniasis lesions may reduce risk of secondary infection with skin bacteria such as Staphylococcus aureus, and that Neotropical Cyatheaceae are a potential source of novel antimicrobial compounds.

scholarly journals Sulfoxides, Analogues of L-Methionine and L-Cysteine As Pro-Drugs against Gram-Positive and Gram-Negative Bacteria

Acta Naturae ◽  
2015 ◽  
Vol 7 (4) ◽  
pp. 128-135 ◽  
Author(s):  
N. V. Anufrieva ◽  
E. A. Morozova ◽  
V. V. Kulikova ◽  
N. P. Bazhulina ◽  
I. V. Manukhov ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
High Reactivity ◽  
Antimicrobial Compounds ◽  
Gram Positive ◽  
Antimicrobial Drugs ◽  
Clostridium Sporogenes ◽  
Gram Negative ◽  
Tautomeric Forms ◽  
Elimination Reactions

The problem of resistance to antibiotics requires the development of new classes of broad-spectrum antimicrobial drugs. The concept of pro-drugs allows researchers to look for new approaches to obtain effective drugs with improved pharmacokinetic and pharmacodynamic properties. Thiosulfinates, formed enzymatically from amino acid sulfoxides upon crushing cells of genus Allium plants, are known as antimicrobial compounds. The instability and high reactivity of thiosulfinates complicate their use as individual antimicrobial compounds. We propose a pharmacologically complementary pair: an amino acid sulfoxide pro-drug and vitamin B6 - dependent methionine -lyase, which metabolizes it in the patients body. The enzyme catalyzes the - and -elimination reactions of sulfoxides, analogues of L-methionine and L-cysteine, which leads to the formation of thiosulfinates. In the present work, we cloned the enzyme gene from Clostridium sporogenes. Ionic and tautomeric forms of the internal aldimine were determined by lognormal deconvolution of the holoenzyme spectrum and the catalytic parameters of the recombinant enzyme in the - and -elimination reactions of amino acids, and some sulfoxides of amino acids were obtained. For the first time, the possibility of usage of the enzyme for effective conversion of sulfoxides was established and the antimicrobial activity of thiosulfinates against Gram-negative and Gram-positive bacteria in situ was shown.

scholarly journals Antimicrobial activity of ethanolic and aqueous extracts of medicinally used tree ferns Alsophila cuspidata and Cyathea microdonta

2018 ◽  
Vol 42 ◽  
pp. 119
Author(s):  
Charlie Longtine ◽  
Adrian Tejedor
Keyword(s):  
Antimicrobial Activity ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Aqueous Extracts ◽  
Antimicrobial Compounds ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Neotropical Tree ◽  
Tree Ferns

Medicinal plants are important components of traditional medicine and sources of novel antimicrobial compounds against drug resistance pathogen strains. This study tested the antimicrobial activity of ethanolic and aqueous extracts of medicinally used Neotropical tree ferns Cyathea microdonta and Alsophila cuspidata against gram positive bacteria and gram negative bacteria using the Kirby-Bauer disc diffusion method. Highest antimicrobial activity was observed in ethanolic extracts, and extracts were more active against gram positive bacteria than gram negative bacteria.  No difference was observed in antimicrobial activity between species or between extracts made from the leaves, stipe, or caudex.  These results suggest that the traditional use of tree fern mucilage as a topical agent for cuts and leishmaniasis lesions may reduce risk of secondary infection with skin bacteria such as Staphylococcus aureus, and that Neotropical Cyatheaceae are a potential source of novel antimicrobial compounds.   

Microanatomy of the Periplasm of Bacillus Licheniformis

1971 ◽  
Vol 29 ◽  
pp. 262-263
Author(s):  
B.K. Ghosh
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Bacillus Licheniformis ◽  
External Environment ◽  
Permeability Barrier ◽  
Periplasmic Space ◽  
Modified Technique ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Periplasm of bacteria is the space outside the permeability barrier of plasma membrane but enclosed by the cell wall. The contents of this special milieu exterior could be regulated by the plasma membrane from the internal, and by the cell wall from the external environment of the cell. Unlike the gram-negative organism, the presence of this space in gram-positive bacteria is still controversial because it cannot be clearly demonstrated. We have shown the importance of some periplasmic bodies in the secretion of penicillinase from Bacillus licheniformis.In negatively stained specimens prepared by a modified technique (Figs. 1 and 2), periplasmic space (PS) contained two kinds of structures: (i) fibrils (F, 100 Å) running perpendicular to the cell wall from the protoplast and (ii) an array of vesicles of various sizes (V), which seem to have evaginated from the protoplast.

Rapid demonstration of septic or infectious arthritis due to Gram-negative bacteria

1992 ◽  
Vol 50 (1) ◽  
pp. 686-687
Author(s):  
Jacob S. Hanker ◽  
Paul R. Gross ◽  
Beverly L. Giammara
Keyword(s):  
Chronic Arthritis ◽  
Blood Cultures ◽  
Gram Negative Bacteria ◽  
Infectious Arthritis ◽  
Bacterial Arthritis ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Blood cultures are positive in approximately only 50 per cent of the patients with nongonococcal bacterial infectious arthritis and about 20 per cent of those with gonococcal arthritis. But the concept that gram-negative bacteria could be involved even in chronic arthritis is well-supported. Gram stains are more definitive in staphylococcal arthritis caused by gram-positive bacteria than in bacterial arthritis due to gram-negative bacteria. In the latter situation where gram-negative bacilli are the problem, Gram stains are helpful for 50% of the patients; they are only helpful for 25% of the patients, however, where gram-negative gonococci are the problem. In arthritis due to gram-positive Staphylococci. Gramstained smears are positive for 75% of the patients.

In-vitro Antioxidant and Antibacterial Activity of Methanolic Extract of Shorea robusta Gaertn. F. Resin

2016 ◽  
Vol 6 (4) ◽  
pp. 68
Author(s):  
Sushma Vashisht ◽  
Manish Pal Singh ◽  
Viney Chawla
Keyword(s):  
Antibacterial Activity ◽  
Methanolic Extract ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Disc Diffusion ◽  
Gram Positive ◽  
Gram Negative ◽  
Shorea Robusta ◽  
Dose Dependent ◽  
Resin Extract

The methanolic extract of the resin of Shorea robusta was subjected to investigate its antioxidant and antibacterial properties its utility in free radical mediated diseases including diabetic, cardiovascular, cancer etc. The methanol extract of the resin was tested for antioxidant activity using scavenging activity of DPPH (1,1-diphenyl-2-picrylhydrazil) radical method, reducing power by FeCl3 and antibacterial activity against gram positive and gram negative bacteria using disc diffusion method. The phytochemical screening considered the presence of triterpenoids, tannins and flavoniods. Overall, the plant extract is a source of natural antioxidants which might be helpful in preventing the progress of various oxidative stress mediated diseases including aging. The half inhibition concentration (IC50) of resin extract of Shorea robusta and ascorbic acid were 35.60 µg/ml and 31.91 µg/ml respectively. The resin extract exhibit a significant dose dependent inhibition of DPPH activity. Antibacterial activity was observed against gram positive and gram negative bacteria in dose dependent manner.Key Words: Shorea robusta, antioxidant, antibacterial, Disc-diffusion, DPPH.

Antibacterial activity of magnesium oxide nanoparticles prepared by Calcination method

2019 ◽  
Vol 10 (03) ◽  
Author(s):  
Elaf Ayad Kadhem ◽  
Miaad Hamzah Zghair ◽  
Sarah , Hussam H. Tizkam, Shoeb Alahmad Salih Mahdi ◽  
Hussam H. Tizkam ◽  
Shoeb Alahmad
Keyword(s):  
Antibacterial Activity ◽  
Magnesium Oxide ◽  
Diffusion Method ◽  
Oxide Nanoparticles ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Magnesium Oxide Nanoparticles ◽  
Agar Disc

magnesium oxide nanoparticles (MgO NPs) were prepared by simple wet chemical method using different calcination temperatures. The prepared NPs were characterized by Electrostatic Discharge (ESD), Scanning Electron Microscope (SEM) and X-ray Diffraction (XRD). It demonstrates sharp intensive peak with the increase of crystallinty and increase of the size with varying morphologies with respect to increase of calcination temperature. Antibacterial studies were done on gram negative bacteria (E.coli) and gram positive bacteria (S.aureus) by agar disc diffusion method. The zones of inhibitions were found larger for gram positive bacteria than gram negative bacteria, this mean, antibacterial MgO NPs activity more active on gram positive bacteria than gram negative bacteria because of the structural differences. It was found that antibacterial activity of MgO NPs was found it has directly proportional with their concentration.

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