scholarly journals Menaquinone biosynthesis inhibition: a review of advancements toward a new antibiotic mechanism

RSC Advances ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 5099-5105 ◽  
Author(s):  
M. Boersch ◽  
S. Rudrawar ◽  
G. Grant ◽  
M. Zunk
Keyword(s):  
Electron Transport ◽  
Antibacterial Action ◽  
Gram Negative Bacteria ◽  
Biosynthesis Pathway ◽  
Gram Positive ◽  
Gram Negative ◽  
Atp Generation ◽  
Bacteria Inhibition

Menaquinone is essential in electron transport and ATP generation in all Gram-positive, and anaerobically respiring Gram-negative bacteria. Inhibition of menaquinone production at different steps of the biosynthesis pathway has shown promising novel antibacterial action.

PHLORETIN: AN ANTIBACTERIAL SUBSTANCE OBTAINED FROM APPLE LEAVES

1952 ◽  
Vol 30 (4) ◽  
pp. 486-489 ◽  
Author(s):  
Russell E. MacDonald ◽  
Charles J. Bishop
Keyword(s):  
Bacterial Cell ◽  
Antibacterial Action ◽  
Gram Negative Bacteria ◽  
Antibacterial Substance ◽  
Gram Positive ◽  
Gram Negative ◽  
Apple Leaves

A crystalline antibacterial substance isolated from apple leaves has been identified as phloretin. It has been shown to inhibit the growth of a number of Gram-positive and Gram-negative bacteria. The activity of the compound is bacteriostatic in nature and is shown in concentrations as low as 30 p.p.m. Its antibacterial action may be related to inhibition of the uptake of phosphorus by the bacterial cell.

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.

In-vitro Antioxidant and Antibacterial Activity of Methanolic Extract of Shorea robusta Gaertn. F. Resin

2016 ◽  
Vol 6 (4) ◽  
pp. 68
Author(s):  
Sushma Vashisht ◽  
Manish Pal Singh ◽  
Viney Chawla
Keyword(s):  
Antibacterial Activity ◽  
Methanolic Extract ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Disc Diffusion ◽  
Gram Positive ◽  
Gram Negative ◽  
Shorea Robusta ◽  
Dose Dependent ◽  
Resin Extract

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.

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.

Antimicrobial Activity of Iron-Halide Complexes Against Gram-Positive and Gram-Negative Bacteria

2020 ◽  
Author(s):  
Nusrat Abedin ◽  
Abdullah Hamed A Alshehri ◽  
Ali M A Almughrbi ◽  
Olivia Moore ◽  
Sheikh Alyza ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Resistance ◽  
Extracellular Dna ◽  
Antibiofilm Activity ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
Antimicrobial Substances ◽  
Mammalian Cell Lines

Antimicrobial resistance (AMR) has become one of the more serious threats to the global health. The emergence of bacteria resistant to antimicrobial substances decreases the potencies of current antibiotics. Consequently, there is an urgent and growing need for the developing of new classes of antibiotics. Three prepared novel iron complexes have a broad-spectrum antimicrobial activity with minimum bactericidal concentration (MBC) values ranging from 3.5 to 10 mM and 3.5 to 40 mM against Gram-positive and Gram-negative bacteria with antimicrobial resistance phenotype, respectively. Time-kill studies and quantification of the extracellular DNA confirmed the bacteriolytic mode of action of the iron-halide compounds. Additionally, the novel complexes showed significant antibiofilm activity against the tested pathogenic bacterial strains at concentrations lower than the MBC. The cytotoxic effect of the complexes on different mammalian cell lines show sub-cytotoxic values at concentrations lower than the minimum bactericidal concentrations.

BAKTERI PADA KARANG SCLERACTINIA DI KAWASAN PERAIRAN BUNAKEN, MOROTAI DAN RAJA AMPAT

2020 ◽  
Vol 8 (1) ◽  
pp. 122
Author(s):  
Eghbert Eghbert Elvan Eghbert Elvan Ampou ◽  
Iis Iis Triyulianti ◽  
Nuryani Widagti ◽  
Suciadi Catur Nugroho ◽  
Yuli Pancawati
Keyword(s):  
Scleractinian Coral ◽  
Gram Negative Bacteria ◽  
Hard Coral ◽  
Field Sampling ◽  
Bacterial Isolation ◽  
Gram Positive ◽  
Coral Mucus ◽  
Gram Negative ◽  
Gram Positive Bacteria

Research on hard coral (Scleractinian coral) contaminated with bacteria is still not much done, especially in Indonesian waters. This study took samples of coral mucus in 2010 at 3 (three) different locations, namely Bunaken (May); Morotai (September) and Raja Ampat (November), which focused on the analysis of Research on hard coral (Scleractinian coral) contaminated with bacteria is still not much done, especially in Indonesian waters. This study took samples of coral mucus in 2010 at 3 (three) different locations, namely Bunaken (May); Morotai (September) and Raja Ampat (November), which focused on the analysis of gram-positive and gram-negative bacteria. The method used for field sampling is time swim, which is by diving at a depth of 5-10 meters for ± 30 minutes and randomly taking samples of coral mucus using siring or by taking directly on corals (reef branching). Mucus samples were analyzed by bacterial isolation in the laboratory. The result shows that there were differences between gram-positive and gram-negative bacteria in the three research sites and that gram-positive bacteria were higher or dominant. Further research that can identify the bacteria species and explain its relationship to the ecosystem is highly recommended.Keywords: Bacteria, Scleractinian coral, gram-positive and -negative, Bunaken, Morotai, Raja Ampat  AbstrakPenelitian tentang karang keras (Scleractinian coral) yang terkontaminasi bakteri masih belum banyak dilakukan, terutama di perairan Indonesia. Penelitian ini mengambil sampel mucus karang pada tahun 2010 di 3 (tiga) lokasi berbeda, yakni Bunaken (Mei); Morotai (September) dan Raja Ampat (November), yang difokuskan pada analisis bakteri gram postif dan gram negatif. Metode yang digunakan untuk pengambilan sampel di lapangan adalah time swim, yaitu dengan penyelaman pada kedalaman 5-10 meter selama ±30 menit dan mengambil sampel mucus karang secara acak menggunakan siring atau dengan mengambil langsung pada karang (fraksi cabang). Sampel mucus dianalisis dengan cara isolasi bakteri di laboratorium. Hasil analisis menunjukkan bahwa ada perbedaan antara bakteri gram positif dan gram negative di tiga lokasi survei dan bakteri gram positif lebih tinggi atau dominan. Penelitian lebih lanjut yang dapat menentukan jenis bakteri serta menjelaskan hubungannya dengan ekosistem sangat disarankan untuk dilakukan.Kata Kunci : Bakteri, Scleractinian coral, gram positif dan negatif, Bunaken, Morotai, Raja Ampat

SDS-NaOH solution for rapid discrimination of Gram-positive and Gram-negative bacteria in urine

2014 ◽  
Vol 35 (8) ◽  
pp. 907
Author(s):  
Hu LI ◽  
Ming-kun CHEN ◽  
Hui WANG ◽  
Yan CHEN ◽  
Xian-hao SU ◽  
...  
Keyword(s):  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Naoh Solution ◽  
Rapid Discrimination

Structure-Activity Relationship and Antimicrobial Evaluation of N-Phenylpyrazole Curcumin Derivatives

2020 ◽  
Vol 16 (4) ◽  
pp. 481-488
Author(s):  
Heli Sanghvi ◽  
Satyendra Mishra
Keyword(s):  
Antibacterial Activity ◽  
Gram Negative Bacteria ◽  
Pyrazole Derivatives ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Curcumin Derivatives ◽  
Structure Activity ◽  
Electron Donating Groups ◽  
Derivatives Of

Background: Curcumin, one of the most important pharmacologically significant natural products, has gained significant consideration among scientists for decades since its multipharmacological activities. 1, 3-Dicarbonyl moiety of curcumin was found to be accountable for the rapid degradation of curcumin molecule. The aim of present work is to replace 1, 3-dicarbonyl moiety of curcumin by pyrazole and phenylpyrazole derivatives with a view to improving its stability and to investigate the role of substitution in N-phenylpyrazole curcumin on its antibacterial activity against both Gram-positive as well as Gram-negative bacteria. Methods: Pyrazole derivatives of curcumin were prepared by heating curcumin with phenyhydrazine/ substituted phenyhydrazine derivatives in AcOH. The residue was purified by silica gel column chromatography. Structures of purified compounds were confirmed by 1H NMR and Mass spectroscopy. The synthesized compounds were evaluated for their antibacterial activity by the microdilution broth susceptibility test method against gram positive (S. aureus) and gram negative (E. coli). Results: Effects of substitution in N-phenylpyrazole curcumin derivatives against S. aureus and E. coli were studied. The most active N-(3-Nitrophenylpyrazole) curcumin (12) exhibits twenty-fold more potency against S. aureus (MIC: 10μg/mL)) and N-(2-Fluoroophenylpyrazole) curcumin (5) fivefold more potency against E. coli (MIC; 50 μg/mL) than N-phenylpyrazole curcumin (4). Whereas, a remarkable decline in anti-bacterial activity against S. aureus and E. coli was observed when electron donating groups were incorporated in N-phenylpyrazole curcumin (4). Comparative studies of synthesized compounds suggest the effects of electron withdrawing and electron donating groups on unsubstituted phenylpyrazole curcumin (4). Conclusion: The structure-activity relationship (SAR) results indicated that the electron withdrawing and electron donating at N-phenylpyrazole curcumin played key roles for their bacterial inhibitory effects. The results of the antibacterial evaluation showed that the synthesized pyrazole derivatives of curcumin displayed moderate to very high activity in S. aureus. In conclusion, the series of novel curcumin derivatives were designed, synthesized and tested for their antibacterial activities against S. aureus and E. coli. Among them, N-(3-Nitrophenylpyrazole curcumin; 12) was most active against S. aureus (Gram-positive) and N-(2-Fluoroophenylpyrazole) curcumin (5) against E. coli (Gram-negative) bacteria.

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