Homology modelling and virtual screening of 3-deoxy-D-manno-octulosonic acid transferase of Aeromonashydrophilaas a potential target for novel natural inhibitory compounds

Author(s):  
P.S. Payal ◽  
Shrinivas Jahageerdar ◽  
Sanath H. Kumar ◽  
Burra V.L.S Prasad

Background: The fish pathogen Aeromonashydrophilais fast acquiringresistance to commonly employed antibiotics in aquaculture. This development has compelled the aquaculture sector to identify and develop new therapeutics to manage the pathogen. Methods: In this study, the protein 3-deoxy-d-manno-2-octulosonic acid (Kdo) transferase of A. hydrophilainvolved in the biosynthesis of the cell wall was studied in-silico as a potential drug target to control this pathogen. The three-dimensional structure of Kdo transferase was predicted by homology modelling using the Modellar 9.15. A total of 7682 natural compounds and 55 known Gram-negative bacterial inhibitors were virtually screened. Laboratory evaluation of inhibitory effects of identified inhibitors against A. hydrophilawas performed using extracts from tea leaves and Astragalus, respectively, by standard disc diffusion method. Results: A molecular model of putative virulence factor Kdowas derived by homology modelling. Eleven compounds were found to be potential inhibitors of Kdo. Among natural compounds, L-Arabinose and Flavan-3,4-diol were identified as the putative therapeutic agents. In the disc diffusion test, the zones of inhibition were observed at 2mg/ml concentrations for tea leaves extracts and 8 mg/ml for Astragalus,suggesting the inhibitory effects of theseextracts. Conclusion: The study shows the utility of essential enzymes such as the protein Kdotransferase asa putative drug target and the potential application of natural compounds in the control of pathogens in aquaculture without the need to use synthetic antimicrobial compounds.

2007 ◽  
Vol 4 (s1) ◽  
pp. 17-20 ◽  
Author(s):  
Nenad Vukovic ◽  
Tanja Milosevic ◽  
Slobodan Sukdolak ◽  
Slavica Solujic

This study was designed to examine the chemical composition of essential oil and thein vitroantimicrobial activities of essential oil and methanol extract ofTeucrium montanum. The inhibitory effects of essential oil and methanol extracts ofT. montanumwere tested against 13 bacterial and three fungal species by using disc-diffusion method. GC/MS analyses revealed that essential oil contains mainly δ-cadinene (17.19%), β-selinene (8.16%) α-calacorene (4.97%), 1,6-dimethyl-4-(1-methylethyl)-naphthalene (4.91%), caryophyllene (4.35%), copaene (4.23%), torreyol (3.91%), 4-terpineol (3.90%), cadina-1,4-diene (3.39%), β-sesquiphellandrene (3.34%), τ-cadinol (3.12%) and γ-curcumene (3.18%). The essential oil has antibacterial as well as antifungal effect.


2008 ◽  
Vol 73 (3) ◽  
pp. 299-305 ◽  
Author(s):  
Nenad Vukovic ◽  
Tanja Milosevic ◽  
Slobodan Sukdolak ◽  
Slavica Solujic

This study was designed to examine the chemical composition of the essential oil and the in vitro antibacterial activities of the essential oil and methanol extract of Teucrium montanum. The inhibitory effects of the essential oil and the methanol extracts of Teucrium montanum were tested against thirteen bacterial species using the disc-diffusion method. GC/MS analyses revealed that the essential oil contained mainly sesquiterpenes, such as ?-cadinene (17.19 %), ?-selinene (8.16 %) and ?-calacorene (4.97 %). The highest activities were obtained with the essential oil of Teucrium montanum against K. pneumoniae, B. subtilis, B. mycoides, E. cloaceae and A. chlorococcum. In addition, comparison of the antibacterial activities of the essential oil and the methanol extract showed that the essential oil exhibited the stronger antibacterial activities.


Author(s):  
Sushma Vashisht ◽  
Manish Pal Singh ◽  
Viney Chawla

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.


Author(s):  
Mubarak A. Alamri ◽  
Ahmed D. Alafnan ◽  
Obaid Afzal ◽  
Alhumaidi B. Alabbas ◽  
Safar M. Alqahtani

Background: The STE20/SPS1-related proline/alanine-rich kinase (SPAK) is a component of WNKSPAK/OSR1 signaling pathway that plays an essential role in blood pressure regulation. The function of SPAK is mediated by its highly conserved C-terminal domain (CTD) that interacts with RFXV/I motifs of upstream activators, WNK kinases, and downstream substrate, cation-chloride cotransporters. Objective: To determine and validate the three-dimensional structure of the CTD of SPAK and to study and analyze its interaction with the RFXV/I motifs. Methods: A homology model of SPAK CTD was generated and validated through multiple approaches. The model was based on utilizing the OSR1 protein kinase as a template. This model was subjected to 100 ns molecular dynamic (MD) simulation to evaluate its dynamic stability. The final equilibrated model was used to dock the RFQV-peptide derived from WNK4 into the primary pocket that was determined based on the homology sequence between human SPAK and OSR1 CTDs. The mechanism of interaction, conformational rearrangement and dynamic stability of the binding of RFQV-peptide to SPAK CTD were characterized by molecular docking and molecular dynamic simulation. Results: The MD simulation suggested that the binding of RFQV induces a large conformational change due to the distribution of salt bridge within the loop regions. These results may help in understanding the relation between the structure and function of SPAK CTD and to support drug design of potential SPAK kinase inhibitors as antihypertensive agents. Conclusion: This study provides deep insight into SPAK CTD structure and function relationship.


2017 ◽  
Vol 10 (2) ◽  
pp. 152-157 ◽  
Author(s):  
Grazielle Millo ◽  
Apa Juntavee ◽  
Ariya Ratanathongkam ◽  
Natsajee Nualkaew ◽  
Peerapattana, Jomjai ◽  
...  

ABSTRACT Aim This study evaluated the in vitro antibacterial effects of the formulated Punica granatum (PG) gel against Streptococcus mutans, Streptococcus sanguinis, and Lactobacillus casei. Materials and methods The PG extract was dissolved in water at 500 mg/mL. High performance liquid chromatography (HPLC) was used for identification and quantification of chemical marker punicalagin. Minimum bactericidal concentration (MBC) and time-kill assay (TKA) were investigated. Antibacterial activities of the formulated PG gel, 2% chlorhexidine (CHX) gel and blank gel were tested by measuring the zones of inhibition through agar well diffusion method. Results The HPLC results showed presence of punicalagin at 2023.58 ± 25.29 μg/mL in the aqueous PG extract and at 0.234% (w/w) in the formulated PG gel. The MBC for S. mutans, S. Sanguinis, and L. casei were 250, 125, and 500 mg/mL respectively. The TKA of 500 mg/mL aqueous PG extract showed total inhibition of S. mutans, S. Sanguinis, and L. casei at 6, 1, and 24 hours contact time respectively. Agar well diffusion revealed that for S. mutans, CHX gel > PG gel > blank gel; for S. sanguinis, CHX gel = PG gel > blank gel; for L. casei, CHX gel > PG gel = blank gel. Comparison of the PG gel potency showed that S. sanguinis = S. mutans > L. casei. Conclusion The PG gel equivalent to 0.234% punicalagin (w/w) inhibited S. mutans and S. sanguinis but not L. casei within 24 hours incubation period and has the potential to be used for caries prevention. How to cite this article Millo G, Juntavee A, Ratanathongkam A, Nualkaew N, Peerapattana J, Chatchiwiwattana S. Antibacterial Inhibitory Effects of Punica Granatum Gel on Cariogenic Bacteria: An in vitro Study. Int J Clin Pediatr Dent 2017;10(2):152-157.


2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
A. Arul Prakash ◽  
S. Balasubramanian ◽  
G. Gunasekaran ◽  
M. Prakash ◽  
P. Senthil Raja

In the present study, effort has been made to find the antimicrobial activity of haemolymph collected from freshwater crab, Paratelphusa hydrodromous. The haemolymph collected was tested for antimicrobial assay by disc diffusion method against clinical pathogens. Five bacterial species, namely, Escherichia coli, Klebsiella pneumonia, Proteus mirabilis, Pseudomonas aeruginosa, Staphylococcus aureus, and five fungal strains, namely and Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Rhizopus sp., and Mucor sp., were selected for the study. The result shows a strong response of haemolymph against the clinical pathogens which confirms the immune mechanism of the freshwater crab.


2021 ◽  
Vol 37 (2) ◽  
pp. 54-64
Author(s):  
D.V. Barabash ◽  
I.A. Butorova

The possibility of using simple and available methods for analyzing deodorants/antiperspirants has been studied. The gravimetric method was shown to have acceptable metrological characteristics under repeatability conditions when evaluating antiperspirant activity. A decrease in the number of microorganisms (CFU) on the axilla skin was observed in a rinse test experiment 4 h and 8 h after the application of deodorants/antiperspirants. The microbial population data were inversely proportional to the antiperspirant activity values of the tested compositions. The sweat secretion reducing decreases the amount of nutrients required for microbial development, which makes it possible to use the rinse test to indirectly evaluate deodorant activity in research and development of personal care products. However, due to its laboriousness and the need for volunteers, the method cannot be recommended for large-scale testing. It was shown that the disc diffusion method (DDM) used to detect Staphylococcus aureus, Pseudomonas aeruginosa and Bacillus subtilis cannot be applied to the assessment of the intrinsic antimicrobial activity of the tested cosmetic compositions. This indicates the necessity of additional studies to select test microorganisms typical for the armpit area. In addition, DDM is useful if the deodorant effect of the composition is created by the addition of low-volatile antibacterial compounds. Therefore, microbiological methods have limited applications and are not suitable for widespread use. deodorant action; antiperspirant action, gravimetry, disc diffusion method, rinse test; deodorant; antiperspirant; cosmetic; efficiency; consumer properties, functional properties This work was supported by MUCTR (project no. K-2020-007).


10.5219/1695 ◽  
2021 ◽  
Vol 15 ◽  
pp. 1112-1119
Author(s):  
Hana Ďúranová ◽  
Veronika Valková ◽  
Lucia Galovičová ◽  
Jana Štefániková ◽  
Miroslava Kačániová

Fungal food spoilage plays a key role in the deterioration of food products, and finding a suitable natural preservative can solve this problem. Therefore, antifungal activity of green mandarin (Citrus reticulata) essential oil (GMEO) in the vapor phase against the growth of Penicillium (P.) expansum and P. chrysogenum inoculated on wheat bread (in situ experiment) was investigated in the current research. The volatile compounds of the GMEO were analyzed by a gas chromatograph coupled to a mass spectrometer (GC–MS), and its antioxidant activity was determined by testing free radical-scavenging capacity (DPPH assay). Moreover, the disc diffusion method was used to analyze the antifungal activity of GMEO in in vitro conditions. The results demonstrate that the Citrus reticulata EO consisted of α-limonene as the most abundant component (71.5%), followed by γ-terpinene (13.9%), and β-pinene (3.5%), and it displayed the weak antioxidant activity with the value of inhibition 5.6 ±0.7%, which corresponds to 103.0 ±6.4 µg TEAC.mL-1. The findings from the GMEO antifungal activity determination revealed that values for the inhibition zone with disc diffusion method ranged from 0.00 ±0.00 (no antifungal effectiveness) to 5.67 ±0.58 mm (moderate antifungal activity). Finally, exposure of Penicillium strains growing on bread to GMEO in vapor phase led to the finding that 250 μL.L-1 of GMEO exhibited the lowest value for mycelial growth inhibition (MGI) of P. expansum (-51.37 ±3.01%) whose negative value reflects even supportive effect of the EO on the microscopic fungus growth. On the other hand, GMEO at this concentration (250 μL.L-1) resulted in the strongest inhibitory action (MGI: 54.15 ±1.15%) against growth of P. chrysogenum. Based on the findings it can be concluded that GMEO in the vapor phase is not an effective antifungal agent against the growth of P. expansum inoculated on bread; however, its antifungal potential manifested against P. chrysogenum suggests GMEO to be an appropriate alternative to the use of chemical inhibitors for bread preservation.


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