scholarly journals Essential Metal Uptake in Gram-negative Bacteria: X-ray Fluorescence, Radioisotopes, and Cell Fractionation

10.3791/57169 ◽  
2018 ◽  
Author(s):  
Christopher D. Radka ◽  
Lauren L. Radford ◽  
Adriana V.F. Massicano ◽  
Lawrence J. DeLucas ◽  
Suzanne E. Lapi ◽  
...  
Keyword(s):  
Metal Uptake ◽  
Gram Negative Bacteria ◽  
Cell Fractionation ◽  
Gram Negative ◽  
Essential Metal ◽  
X Ray

scholarly journals Rational Design of Ag/ZnO Hybrid Nanoparticles on Sericin/Agarose Composite Film for Enhanced Antimicrobial Applications

2020 ◽  
Vol 22 (1) ◽  
pp. 105
Author(s):  
Wanting Li ◽  
Zixuan Huang ◽  
Rui Cai ◽  
Wan Yang ◽  
Huawei He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Antimicrobial Activity ◽  
Composite Film ◽  
Water Absorption ◽  
Rational Design ◽  
Hybrid Nanoparticles ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
X Ray

Silver-based hybrid nanomaterials are receiving increasing attention as potential alternatives for traditional antimicrobial agents. Here, we proposed a simple and eco-friendly strategy to efficiently assemble zinc oxide nanoparticles (ZnO) and silver nanoparticles (AgNPs) on sericin-agarose composite film to impart superior antimicrobial activity. Based on a layer-by-layer self-assembly strategy, AgNPs and ZnO were immobilized on sericin-agarose films using the adhesion property of polydopamine. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray powder diffraction spectroscopy were used to show the morphology of AgNPs and ZnO on the surface of the composite film and analyze the composition and structure of AgNPs and ZnO, respectively. Water contact angle, swelling ratio, and mechanical property were determined to characterize the hydrophilicity, water absorption ability, and mechanical properties of the composite films. In addition, the antibacterial activity of the composite film was evaluated against Gram-positive and Gram-negative bacteria. The results showed that the composite film not only has desirable hydrophilicity, high water absorption ability, and favorable mechanical properties but also exhibits excellent antimicrobial activity against both Gram-positive and Gram-negative bacteria. It has shown great potential as a novel antimicrobial biomaterial for wound dressing, artificial skin, and tissue engineering.

Synthesis and Characterization of Cadmium with Titanium Oxide (Cd-TiO2) Nanocomposite: Testing its Antibacterial Effect

2021 ◽  
Vol 12 (4) ◽  
pp. 2523-2529
Author(s):  
Daniel Sam N ◽  
Anish C I ◽  
Sabeena G ◽  
Rajaduraipandian S ◽  
Manobala ◽  
...  
Keyword(s):  
Sol Gel ◽  
Gram Negative Bacteria ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Gram Negative ◽  
X Ray ◽  
Weight Percentage ◽  
Inhibition Concentration ◽  
Xrd Patterns

Sol gel methods were used for the study of the antimicrobial activity of Cd-TiO2 against gram-negative and positive bacteria. These Cd-TiO2 have been characterized by various optical and techniques. They have been exhibited by X-ray diffraction, scanning electron microscopy, ultraviolet spectroscopy, and infrared spectroscopy. The structures of the various XRD patterns indicate that the product has a structure. The particle size of Cd-TiO2 is 35nm. The SEM images confirm the spherical appearance of the sample. The energy X-ray spectra have been confirmed as well and then C, O, Ti, Cd, Pt element are present in Cd-TiO2. The weight percentage of Cadmium is 5.8%, Ti is 51.03%, C is 5.13% and O is 31.75% in Cd-TiO2. BET image shows that the major pore size distribution of Cd-TiO2 is ranged from 2.24 nm. The Cd-TiO2 that the antibacterial activity when tested against the pathogens only gram-negative bacteria such as Pseudomonas. The zone of minimum inhibition concentration was measured in a range of 20mm in 25μl and 30mm in 100μl.

ANTIMICROBIAL ACTIVITY OF COPPER KAOLINITE AND SURFACTANT MODIFIED COPPER KAOLINITE AGAINST GRAM POSITIVE AND GRAM NEGATIVE BACTERIA

2016 ◽  
Vol 78 (3-2) ◽  
Author(s):  
Nor Syafawani Sarah Md Saad ◽  
Nik Ahmad Nizam Nik Malek ◽  
Chun Shiong Chong
Keyword(s):  
Antimicrobial Activity ◽  
Synergistic Effects ◽  
Wide Spectrum ◽  
Copper Nitrate ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
X Ray ◽  
Gram Positive Bacteria ◽  
Diffusion Technique

The aim of this research was to determine the antimicrobial activity of kaolinite modified with antimicrobial compounds against Gram positive and Gram negative bacteria. Copper kaolinite (Cu-kaolinite) was prepared by loading raw kaolinite with copper nitrate trihydrate (CuNO3) while surfactant modified Cu-kaolinite (SM-Cu-kaolinite) was prepared by adding cationic surfactants hexadecyltrimethyl ammonium (HDTMA) on Cu-Kaolinite. Samples was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) analyzer. The antimicrobial activity of the samples was tested against Gram negative bacteria (Escherichia coli ATCC 11229 and Pseudomonas aeruginosa ATCC 15442), and Gram positive bacteria (Staphylococcus aureus ATCC 6538 and Enterococcus faecalis ATCC 29212) through disc diffusion technique (DDT) and minimum inhibition concentration (MIC). The results showed that the antimicrobial activity of Cu-kaolinite increased after modified with HDTMA due to the synergistic effects of Cu ions and HDTMA molecules on the kaolinite. The antimicrobial activity for surfactant modified Cu-kaolinite was greater for Gram positive bacteria compared to Gram negative bacteria. In conclusion, the attachment of HDTMA on Cu-kaolinite contributed to the enhanced antimicrobial activity against wide spectrum of bacteria (Gram positive and Gram negative bacteria).

Mannich Reaction Product of Quinolin-8-ol (Oxine) and its Antibacterial Activity

1997 ◽  
Vol 50 (8) ◽  
pp. 861 ◽  
Author(s):  
Shaheen Faizi ◽  
Bina Shaheen Siddiqui ◽  
Rubeena Saleem ◽  
Farzana Akhtar ◽  
Khursheed Ali Khan ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Single Crystal ◽  
Mannich Reaction ◽  
Gram Negative Bacteria ◽  
X Ray Diffraction ◽  
Gram Positive ◽  
Gram Negative ◽  
Antimicrobial Screening ◽  
X Ray

Quinolin-8-ol (1) on reaction with 2,6-dichloroaniline and m-nitrobenzaldehyde afforded 7-(α-hydroxy- m-nitrobenzyl)quinolin-8-ol (2), which is an unusual Mannich reaction product. The structure of (2) was determined by spectroscopic and single-crystal X-ray diffraction studies. Preliminary antimicrobial screening showed that (1) and (2) have activity against a large number of Gram-positive and Gram-negative bacteria.

Nitric Oxide Inhibitory Activity of Xanthones from the Green Fruits of Cratoxylum formosum ssp. pruniflorum

2010 ◽  
Vol 63 (11) ◽  
pp. 1550 ◽  
Author(s):  
Nawong Boonnak ◽  
Achjana Khamthip ◽  
Chatchanok Karalai ◽  
Suchada Chantrapromma ◽  
Chanita Ponglimanont ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Antibacterial Activity ◽  
Inhibitory Activity ◽  
Spectroscopic Methods ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
X Ray ◽  
X Ray Crystallography ◽  
Ic50 Values ◽  
Mic Value

Three new xanthones, pruniflorone M-O (1–3), and a new xanthonolignoid, 3-methoxy-5′-demethoxycadensin G (4), were isolated from the green fruits of Cratoxylum formosum ssp. pruniflorum along with three known xanthones (5–7) and a known flavonoid (8). Their structures were elucidated by spectroscopic methods and the structure of 1 was also determined by X-ray crystallography. Compounds 2 and 7 showed potent nitric oxide inhibitory activity with IC50 values of 4.4 and 4.3 μM, respectively. Moreover, 7 also showed strong antibacterial activity against both Gram-positive and Gram-negative bacteria with an MIC value of 4.67 μg mL–1.

scholarly journals The atypical thiol-disulfide exchange protein α-DsbA2 from Wolbachia pipientis is a homotrimeric disulfide isomerase

2018 ◽  
Author(s):  
Patricia M. Walden ◽  
Premkumar Lakshmanane ◽  
Maria Halili ◽  
Begoña Heras ◽  
Gordon J. King ◽  
...  
Keyword(s):  
Disulfide Bonds ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Disulfide Isomerase ◽  
Wolbachia Pipientis ◽  
X Ray ◽  
Disulfide Exchange ◽  
E Coli ◽  
Master Regulators ◽  
X Ray Scattering

AbstractDiSulfide Bond (DSB) oxidative folding enzymes are master regulators of virulence localized to the periplasm of many Gram-negative bacteria. The archetypal DSB machinery from Escherichia coli K12 has a dithiol oxidizing redox relay pair (DsbA/B), a disulfide isomerizing redox relay pair (DsbC/D) and specialist reducing enzymes DsbE and DsbG that also interact with DsbD. By contrast the Gram-negative bacterium Wolbachia pipientis encodes just three DSB enzymes. Two of these α-DsbA1 and α-DsbB form a redox relay pair analogous to E. coli DsbA/B. The third enzyme α-DsbA2 incorporates a DsbA-like sequence but does not interact with α-DsbB. In comparison with other DsbA enzymes, α-DsbA2 has ∼50 extra N-terminal residues. The crystal structure of α-DsbA2ΔN, the N-terminally truncated form in which these residues are removed confirms the DsbA-like nature of this domain. However, α-DsbA2 does not have DsbA-like activity: it is structurally and functionally different as a consequence of its N-terminal residues. First, α-DsbA2 is a powerful disulfide isomerase and a poor dithiol oxidase – ie its role is to shuffle rather than introduce disulfide bonds. Moreover, small-angle X-ray scattering of α-DsbA2 reveals a homotrimeric arrangement. Our results allow us to draw conclusions about the factors required for functionally equivalent enzymatic activity across structurally diverse protein architectures.

scholarly journals Structure and Stoichiometry of the Ton Molecular Motor

2020 ◽  
Vol 21 (2) ◽  
pp. 375 ◽  
Author(s):  
Herve Celia ◽  
Nicholas Noinaj ◽  
Susan K Buchanan
Keyword(s):  
Outer Membrane ◽  
Mode Of Action ◽  
Molecular Motor ◽  
Proton Gradient ◽  
Gram Negative Bacteria ◽  
Periplasmic Space ◽  
Inner Membrane ◽  
Gram Negative ◽  
X Ray ◽  
X Ray Crystallography

The Ton complex is a molecular motor that uses the proton gradient at the inner membrane of Gram-negative bacteria to generate force and movement, which are transmitted to transporters at the outer membrane, allowing the entry of nutrients into the periplasmic space. Despite decades of investigation and the recent flurry of structures being reported by X-ray crystallography and cryoEM, the mode of action of the Ton molecular motor has remained elusive, and the precise stoichiometry of its subunits is still a matter of debate. This review summarizes the latest findings on the Ton system by presenting the recently reported structures and related reports on the stoichiometry of the fully assembled complex.

scholarly journals Gram-negative trimeric porins have specific LPS binding sites that are essential for porin biogenesis

2016 ◽  
Vol 113 (34) ◽  
pp. E5034-E5043 ◽  
Author(s):  
Wanatchaporn Arunmanee ◽  
Monisha Pathania ◽  
Alexandra S. Solovyova ◽  
Anton P. Le Brun ◽  
Helen Ridley ◽  
...  
Keyword(s):  
Binding Sites ◽  
Calcium Ion ◽  
Gram Negative Bacteria ◽  
Core Oligosaccharide ◽  
Gram Negative ◽  
X Ray ◽  
Cross Links ◽  
Phosphate Groups ◽  
Positively Charged ◽  
Lps Binding

The outer membrane (OM) of gram-negative bacteria is an unusual asymmetric bilayer with an external monolayer of lipopolysaccharide (LPS) and an inner layer of phospholipids. The LPS layer is rigid and stabilized by divalent cation cross-links between phosphate groups on the core oligosaccharide regions. This means that the OM is robust and highly impermeable to toxins and antibiotics. During their biogenesis, OM proteins (OMPs), which function as transporters and receptors, must integrate into this ordered monolayer while preserving its impermeability. Here we reveal the specific interactions between the trimeric porins of Enterobacteriaceae and LPS. Isolated porins form complexes with variable numbers of LPS molecules, which are stabilized by calcium ions. In earlier studies, two high-affinity sites were predicted to contain groups of positively charged side chains. Mutation of these residues led to the loss of LPS binding and, in one site, also prevented trimerization of the porin, explaining the previously observed effect of LPS mutants on porin folding. The high-resolution X-ray crystal structure of a trimeric porin–LPS complex not only helps to explain the mutagenesis results but also reveals more complex, subtle porin–LPS interactions and a bridging calcium ion.

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