Effect of Zataria multiflora Boiss. essential oil and nisin on Salmonella typhimurium and Staphylococcus aureus in a food model system and on the bacterial cell membranes

2008 ◽  
Vol 41 (10) ◽  
pp. 1050-1057 ◽  
Author(s):  
Mir-Hassan Moosavy ◽  
Afshin Akhondzadeh Basti ◽  
Ali Misaghi ◽  
Taghi Zahraei Salehi ◽  
Reza Abbasifar ◽  
...  
Author(s):  
Maria A. Schumacher ◽  
Tomoo Ohashi ◽  
Lauren Corbin ◽  
Harold P. Erickson

Bacterial cytokinesis is mediated by the Z-ring, which is formed by the prokaryotic tubulin homolog FtsZ. Recent data indicate that the Z-ring is composed of small patches of FtsZ protofilaments that travel around the bacterial cell by treadmilling. Treadmilling involves a switch from a relaxed (R) state, favored for monomers, to a tense (T) conformation, which is favored upon association into filaments. The R conformation has been observed in numerous monomeric FtsZ crystal structures and the T conformation in Staphylococcus aureus FtsZ crystallized as assembled filaments. However, while Escherichia coli has served as a main model system for the study of the Z-ring and the associated divisome, a structure has not yet been reported for E. coli FtsZ. To address this gap, structures were determined of the E. coli FtsZ mutant FtsZ(L178E) with GDP and GTP bound to 1.35 and 1.40 Å resolution, respectively. The E. coli FtsZ(L178E) structures both crystallized as straight filaments with subunits in the R conformation. These high-resolution structures can be employed to facilitate experimental cell-division studies and their interpretation in E. coli.


Molecules ◽  
2020 ◽  
Vol 25 (17) ◽  
pp. 3955 ◽  
Author(s):  
Xin Wang ◽  
Yi Shen ◽  
Kiran Thakur ◽  
Jinzhi Han ◽  
Jian-Guo Zhang ◽  
...  

Though essential oils exhibit antibacterial activity against food pathogens, their underlying mechanism is understudied. We extracted ginger essential oil (GEO) using supercritical CO2 and steam distillation. A chemical composition comparison by GC-MS showed that the main components of the extracted GEOs were zingiberene and α-curcumene. Their antibacterial activity and associated mechanism against Staphylococcus aureus and Escherichia coli were investigated. The diameter of inhibition zone (DIZ) of GEO against S. aureus was 17.1 mm, with a minimum inhibition concentration (MIC) of 1.0 mg/mL, and minimum bactericide concentration (MBC) of 2.0 mg/mL. For E. coli, the DIZ was 12.3 mm with MIC and MBC values of 2.0 mg/mL and 4.0 mg/mL, respectively. The SDS-PAGE analysis revealed that some of the electrophoretic bacterial cell proteins bands disappeared with the increase in GEO concentration. Consequently, the nucleic acids content of bacterial suspension was raised significantly and the metabolic activity of bacteria was markedly decreased. GEO could thus inhibit the expression of some genes linked to bacterial energy metabolism, tricarboxylic acid cycle, cell membrane-related proteins, and DNA metabolism. Our findings speculate the bactericidal effects of GEO primarily through disruption of the bacterial cell membrane indicating its suitability in food perseveration.


2020 ◽  
Vol 1 (1) ◽  
pp. 45-50
Author(s):  
Shova D.C. ◽  
Binita Maharjan ◽  
Timila Shrestha ◽  
Samjhana Bharati ◽  
Ram Lal Shrestha

Fruit part of Trachyspermum ammi (L.) Sprague was subjected to extraction of essential oil by hydrodistillation in Clevenger apparatus. So collected essential oil was analyzed by GC-MS for its composition and exhibited the presence of 10 different compounds. The most abundant were γ-terpinene (53.81%) and thymol (29.40%). Antibacterial activity was performed against six bacterial species and Staphylococcus aureus, Enterobacter cloaceae and Bacillus subtilis were the most susceptible to the essential oil showing zone of inhibition (ZOI) 1.4, 1.5 and 1.4 cm respectively. The IC50 value of the oil against DPPH was found to be 0.94 mg/mL. The LC50 value of essential oil of T. ammi against brine shrimp was found 26.2 μg/mL.


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