An AIEgen as an Intrinsic Antibacterial Agent for Light‐Up Detection and Inactivation of Intracellular Gram‐Positive Bacteria

2021 ◽  
pp. 2100885
Author(s):  
Tianjiao Dai ◽  
Bingpeng Guo ◽  
Guobin Qi ◽  
Shidang Xu ◽  
Cheng Zhou ◽  
...  
Keyword(s):  
Antibacterial Agent ◽  
Gram Positive ◽  
Gram Positive Bacteria

scholarly journals A phytomass-inspired carbon and its importance as an antibacterial agent against human pathogens

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
N. Anvarsha ◽  
P. Kalyani
Keyword(s):  
Activated Carbon ◽  
Elemental Analysis ◽  
Antibacterial Agent ◽  
Low Cost ◽  
Diffusion Method ◽  
Vitex Negundo ◽  
Human Pathogens ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Abstract Background Imprudent use of antimicrobial drugs has resulted in the microbial resistance among the known microbes and hence we foresee a pressing need towards the development of novel, low-cost, and high potent antimicrobials which should be munificent by nature. In the pursuit of the above, phosphoric acid activated low-cost carbon was produced from a renewable phytomass precursor viz., leaves of Vitex negundo L. plant and explored for its antibacterial efficacy against four human pathogens viz., S. aureus, S. pyogenes (Gram-positive bacteria), and E. coli, P. aeruginosa (Gram-negative bacteria) by adopting well diffusion method. Carbon yield, burn-off, phase purity, elemental composition, particle morphology, and surface functionalities have been studied by ultimate elemental analysis, X-ray diffractometry, elemental analysis, scanning electron microscopy, and Fourier transform infrared spectrophotometry respectively. Minimal inhibition concentration (MIC) was also followed. Plausible mechanism of killing the pathogens by the above activated carbon was also provided. Results Vitex negundo leaves derived activated carbon (VNLAC) was found to contain large number of O-, S- and N-containing surface groups which are supposedly responsible for bestowing antibacterial properties to the carbon derived from Vitex negundo leaves. It has emerged as a potential antibacterial agent for many Gram-negative as well as Gram-positive bacteria. The inhibition zone of mean diameters ranged from 9 to 25 mm against all the pathogens was significantly (p < 0.05) less than that of the control viz., ciprofloxacin. Thus, the fundamental experimental results may extend the limits of carbon sources but also the conventional idea of obtaining active carbon to apply in technologies where carbon is inevitable. Conclusion The work not only demonstrates the promising potential of VNLAC as an efficient antibacterial agent but also presents a feasible mechanism of action of removing pathogens. Vitex negundo-derived carbon may become a cheap substitute for cost-prohibitive drugs. The findings of the work illustrate an easy choice as an antibacterial for topical application at infected sites.

Influence of Cell Wall Composition on the Fossilisation of Bacteria and the Implications for the Search for Early Life Forms

1997 ◽  
Vol 161 ◽  
pp. 491-504 ◽  
Author(s):  
Frances Westall
Keyword(s):  
Cell Wall ◽  
Life Forms ◽  
Cation Binding ◽  
Positive Bacterium ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Transmission Electron ◽  
Hydrothermal Sediments ◽  
Identification Of Bacteria ◽  
The Difference

AbstractThe oldest cell-like structures on Earth are preserved in silicified lagoonal, shallow sea or hydrothermal sediments, such as some Archean formations in Western Australia and South Africa. Previous studies concentrated on the search for organic fossils in Archean rocks. Observations of silicified bacteria (as silica minerals) are scarce for both the Precambrian and the Phanerozoic, but reports of mineral bacteria finds, in general, are increasing. The problems associated with the identification of authentic fossil bacteria and, if possible, closer identification of bacteria type can, in part, be overcome by experimental fossilisation studies. These have shown that not all bacteria fossilise in the same way and, indeed, some seem to be very resistent to fossilisation. This paper deals with a transmission electron microscope investigation of the silicification of four species of bacteria commonly found in the environment. The Gram positiveBacillus laterosporusand its spore produced a robust, durable crust upon silicification, whereas the Gram negativePseudomonas fluorescens, Ps. vesicularis, andPs. acidovoranspresented delicately preserved walls. The greater amount of peptidoglycan, containing abundant metal cation binding sites, in the cell wall of the Gram positive bacterium, probably accounts for the difference in the mode of fossilisation. The Gram positive bacteria are, therefore, probably most likely to be preserved in the terrestrial and extraterrestrial rock record.

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.

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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