Inhibitory effects of auxins and related substances on the activity of an Arabidopsis glutathione S-transferase isozyme expressed in Escherichia coli

Liquid smoke extracts have traditionally been used as flavoring agents, are known to possess antioxidant properties, and serve as natural alternatives to conventional antimicrobials. The antimicrobial efficacies of commercial liquid smoke samples may vary depending on their source and composition and the methods used to extract and concentrate the smoke. We investigated the MICs of eight commercial liquid smoke samples against Salmonella Enteritidis, Staphylococcus aureus, and Escherichia coli. The commercial liquid smoke samples purchased were supplied by the manufacturer as water-based or concentrated extracts of smoke from different wood sources. The MICs of the commercial smokes to inhibit the growth of foodborne pathogens ranged from 0.5 to 6.0% for E. coli, 0.5 to 8.0% for Salmonella, and 0.38 to 6% for S. aureus. The MIC for each liquid smoke sample was similar in its effect on both E. coli and Salmonella. Solvent-extracted antimicrobials prepared using pecan shells displayed significant differences between their inhibitory concentrations depending on the type of solvent used for extraction. The results indicated that the liquid smoke samples tested in this study could serve as effective natural antimicrobials and that their inhibitory effects depended more on the solvents used for extraction than the wood source.

Download Full-text

Synthesis Of Copper Nanometal Coupled With Vitamin-E And Investigating Its Potential To Control Oxidative Cell Damage And Microbial Spoilage In Seafood

Journal of University of Shanghai for Science and Technology ◽

10.51201/jusst/21/08456 ◽

2021 ◽

Vol 23 (08) ◽

pp. 678-693

Author(s):

Haris. V.T ◽

◽

Manohar. M ◽

Kuppannan Gobianand ◽

◽

...

Keyword(s):

Escherichia Coli ◽

Vitamin E ◽

Mtt Assay ◽

Cell Damage ◽

Green Emission ◽

Plate Count ◽

Diffusion Method ◽

Inhibitory Effects ◽

Microbial Spoilage ◽

Spoilage Bacteria

The metabolism of spoilage organism in the seafood is a major cause of fish spoilage. Lipid oxidation leads to production of intermediate peroxides causing bad odor and offflavour producing compounds. Hence, based on the hurdle technology method and applications of nanotechnology, the inhibitory effects of copper oxide nanoparticles coupled with vitamin-E (CuONPs+VE) was investigated with the aim of controlling the oxidative cell damage in seafood by estimating Reacting Oxygen Species (ROS) using 2’,7’- dichlorodihydrofluorescein diacetate (DCF) and preventing microbial spoilage by studying the cell viability using MTT assay in the present study. The MTT assay reveals that the CuONPs+VE inhibited the metabolic activity of spoilage bacteria which was confirmed from the inhibition percentage values against the test organisms. The CuONPs+VE exposed Escherichia coli reduced upto 86 ± 0.57% after enumerating the CFU in a Plate Count Agar media. Salmonella sp and Shigella sp exhibited 89 ± 1.04% and 85 ± 0.25% respectively. The qualitative inhibitory effect of Nanometal vitamin complex against three test bacteria, were evaluated by agar diffusion method. Among the four different concentrations of Nanometal vitamin complex, the higher concentration (4X – 40μg/ml) exhibited maximum inhibitory effects in terms of zone of clearance. Against Escherichia coli, 12.3 ± 1.25mm of inhibitory zones were found evident. Salmonella sp showed 15.6 ± 0.57mm of inhibitory zones and Shigella sp revealed the inhibition zone of about 16.6 ± 1.04mm. The anti-oxidative defence mechanisms operating in the cells for scavenging of ROS was performed using DCF. The cells which are pre-incubated with CuONPs+VE and then exposed to H2O2 show insignificant green emission indicating a clear advantage of the nanoparticle form of vitamin-E (CuONPs+VE) in preventing oxidative cell death.

Download Full-text