scholarly journals A-Ring-Modified Triterpenoids and Their Spermidine–Aldimines with Strong Antibacterial Activity

Molbank ◽  
10.3390/m1078 ◽  
2019 ◽  
Vol 2019 (3) ◽  
pp. M1078 ◽  
Author(s):  
Kazakova ◽  
Brunel ◽  
Khusnutdinova ◽  
Negrel ◽  
Giniyatullina ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Antimicrobial Properties ◽  
Antimicrobial Activities ◽  
Amide Bond ◽  
Gram Negative Bacteria ◽  
Human Pathogens ◽  
Gram Negative ◽  
Weak Minimum

Synthesis of A-ring-modified lupane, oleanane and ursane type triterpenoid conjugates with spermidine through an aldimine linkage or diethylentriamine via an amide bond is described. These derivatives were evaluated for their in vitro antimicrobial properties against human pathogens. Except for derivatives 1 and 7, all compounds have moderate to weak minimum inhibitory concentrations (MICs) against Gram-positive Staphylococcus aureus bacteria, with MICs varying from 3.125 to 200 µM. Compound 11 is efficient against Escherichia coli and Pseudomonas aeruginosa, with MICs of 25 and 50 µM, respectively, while all other derivatives do not possess important antimicrobial activities against these Gram-negative bacteria.

scholarly journals In VitroCytotoxic, Antioxidant, and Antimicrobial Activities ofMesua beccariana(Baill.) Kosterm.,Mesua ferreaLinn., andMesua congestifloraExtracts

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Soek Sin Teh ◽  
Gwendoline Cheng Lian Ee ◽  
Siau Hui Mah ◽  
Yoke Keong Yong ◽  
Yang Mooi Lim ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Bacillus Cereus ◽  
Antioxidant Activities ◽  
Human Cancer ◽  
Antimicrobial Activities ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Methanol Extracts

Thein vitrocytotoxicity tests on the extracts ofMesua beccariana,M. ferrea, andM. congestifloraagainst Raji, SNU-1, HeLa, LS-174T, NCI-H23, SK-MEL-28, Hep-G2, IMR-32, and K562 were achieved using MTT assay. The methanol extracts ofMesua beccarianashowed its potency towards the proliferation of B-lymphoma cell (Raji). In addition, only the nonpolar to semipolar extracts (hexane to ethyl acetate) of the threeMesuaspecies indicated cytotoxic effects on the tested panel of human cancer cell lines. Antioxidant assays were evaluated using DPPH scavenging radical assay and Folin-Ciocalteu method. The methanol extracts ofM. beccarianaandM. ferreashowed high antioxidant activities with low EC50values of 12.70 and 9.77 μg/mL, respectively, which are comparable to that of ascorbic acid (EC50 = 5.62 μg/mL). Antibacterial tests were carried out using four Gram positive and four Gram negative bacteria onMesua beccarianaextracts. All the extracts showed negative results in the inhibition of Gram negative bacteria. Nevertheless, methanol extracts showed some activities against Gram positive bacteria which areBacillus cereus, methicillin-sensitiveStaphylococcus aureus(MSSA), and methicillin-resistantStaphylococcus aureus(MRSA), while the hexane extract also contributed some activities towardsBacillus cereus.

scholarly journals Reactions of tin- and triorganotin(IV) isopropoxides with thymol derivative: Synthesis, characterization and in vitro antimicrobial screening

2013 ◽  
Vol 78 (9) ◽  
pp. 1323-1333 ◽  
Author(s):  
Garima Matela ◽  
Robina Aman ◽  
Chetan Sharma ◽  
Smita Chaudhary
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Nuclear Magnetic Resonance ◽  
Antibacterial Activity ◽  
Gram Negative Bacteria ◽  
Carboxylate Group ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
1H Nuclear Magnetic Resonance

A new series of diisopropyloxytin- and triorganotin(IV) complexes of H2hbgl (1) of the general formula Sn(OPri)2(hbgl) (2), Sn(OPri)2(Hhbgl)2 (3), Ph3Sn(Hhbgl) (4), Bu3Sn(Hhbgl) (5) and Me3Sn(Hhbgl) (6), [where H2hbgl= a ligand of thymol derivative namely, N-(2-hydroxy-3-isopropyl-6-methyl benzyl)Glycine] were synthesized by reacting tin- and triorganotin(IV) chloride with the ligand, with the aid of sodium iso-propoxide in appropriate stiochiometric ratios (1:1 and 1:2). These complexes were characterized by elemental analysis, IR, 1H nuclear magnetic resonance. The spectral data suggest that the carboxylate group, in complexes 2-5, was bonded in a bidentate manner, while a unidentate bonding was observed in complex 6. All five complexes were tested in vitro for their antibacterial activity against Gram-positive bacteria namely, Staphylococcus aureus MTCC 96, Bacillus subtilis MTCC 121 and two Gram-negative bacteria namely, Escherichia coli MTCC 1652 and Pseudomonas aeruginosa MTCC 741. All the five complexes were also tested against three pathogenic fungal strains namely, Aspergillus niger, A. flavus and Penicillium sp.

scholarly journals One-Pot Synthesis of Some Novel N-Aryl-1,4-Dihydropyridines Derivatives Bearing Nitrogen Mustard

2015 ◽  
Vol 48 ◽  
pp. 61-67 ◽  
Author(s):  
P.M. Singala ◽  
Viresh H. Shah
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Streptococcus Pyogenes ◽  
Nitrogen Mustard ◽  
Gram Negative Bacteria ◽  
Aspergillus Clavatus ◽  
One Pot ◽  
Gram Negative ◽  
Gram Positive Bacteria

The synthesis of a novel dihydropyridine, bearing carbethoxy groups at C(3) and C(5), respectively, has been achieved by applying three component Hantzsch-type condensation. The products were assayed for their in vitro biological assay antibacterial activity against with two Gram-positive bacteria Staphylococcus aureus MTCC-96, Streptococcus pyogenes MTCC 443, two Gram-negative bacteria Escherichia coli MTCC 442, Pseudomonas aeruginosa MTCC 441 and three fungal strains Candida albicans MTCC 227, Aspergillus Niger MTCC 282, Aspergillus clavatus MTCC 1323 taking ampicillin, chloramphenicol, ciprofloxacin, norfloxacin, nystatin, and griseofulvin as standard drugs.

Antimicrobial and cytotoxic activity of Macrophomina phaseolina isolated from gummosis infected citrus reticulata

2013 ◽  
pp. 125-133
Author(s):  
Rubal C Das ◽  
Rajib Banik ◽  
Robiul Hasan Bhuiyan ◽  
Md Golam Kabir
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Brine Shrimp ◽  
Inhibitory Concentration ◽  
Lethal Dose ◽  
Macrophomina Phaseolina ◽  
Chloroform Extract ◽  
Citrus Reticulata ◽  
Gram Negative Bacteria ◽  
Gram Negative

Macrophomina phaseolina is one of the pathogenic organisms of gummosis disease of orange tree (Citrus reticulata). The pathogen was identified from the observation of their colony size, shape, colour, mycelium, conidiophore, conidia, hyaline, spore, and appressoria in the PDA culture. The crude chloroform extracts from the organism showed antibacterial activity against a number of Gram positive and Gram-negative bacteria. The crude chloroform extract also showed promising antifungal activity against three species of the genus Aspergillus. The minimum inhibitory concentration (MIC) of the crude chloroform extract from M. phaseolina against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Shigella sonnie were 128 ?gm, 256 ?gm, 128 ?gm and 64 ?gm/ml respectively. The LD50 (lethal dose) values of the cytotoxicity assay over brine shrimp of the crude chloroform extract from M. phaseolina was found to be 51.79 ?gm/ml. DOI: http://dx.doi.org/10.3329/cujbs.v5i1.13378 The Chittagong Univ. J. B. Sci.,Vol. 5(1 &2):125-133, 2010

Cefotaxime and amikacin: results of in vitro and in vivo studies against Gram-negative bacteria and Staphylococcus aureus

1980 ◽  
Vol 6 (suppl A) ◽  
pp. 55-61 ◽  
Author(s):  
J. Klastersky ◽  
H. Gaya ◽  
S. H. Zinner ◽  
C. Bernard ◽  
J-C. Ryff ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
In Vivo Studies ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
And Staphylococcus Aureus

scholarly journals In Vitro Anti-Helicobacter pyloriActivities of New Rifamycin Derivatives, KRM-1648 and KRM-1657

1999 ◽  
Vol 43 (5) ◽  
pp. 1072-1076 ◽  
Author(s):  
Junko K. Akada ◽  
Mutsunori Shirai ◽  
Kenji Fujii ◽  
Kiwamu Okita ◽  
Teruko Nakazawa
Keyword(s):  
Helicobacter Pylori ◽  
Cell Lysis ◽  
Antimicrobial Activities ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Bactericidal Activities ◽  
H Pylori ◽  
Time Kill

ABSTRACT The new rifamycin derivatives KRM-1657 and KRM-1648 were evaluated for their in vitro antimicrobial activities against 44 strains ofHelicobacter pylori. Although the drugs were not very active against other gram-negative bacteria, the MICs at which 90% of isolates are inhibited for these drugs were lower (0.002 and 0.008 μg/ml, respectively) than those of amoxicillin and rifampin forH. pylori. Time-kill studies revealed that the bactericidal activities of these agents were due to cell lysis. The results presented here indicate that these new rifamycin derivatives may be useful for the eradication of H. pylori infections.

Functional analysis of the lysis genes of Staphylococcus aureus phage P68 in Escherichia coli

Microbiology ◽  
2005 ◽  
Vol 151 (7) ◽  
pp. 2331-2342 ◽  
Author(s):  
Marian Takáč ◽  
Angela Witte ◽  
Udo Bläsi
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Functional Analysis ◽  
Transmembrane Domains ◽  
Class I ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Reading Frame ◽  
Double Stranded Dna ◽  
A Cell

Double-stranded DNA phages of both Gram-positive and Gram-negative bacteria typically use a holin–endolysin system to achieve lysis of their host. In this study, the lysis genes of Staphylococcus aureus phage P68 were characterized. P68 gene lys16 was shown to encode a cell-wall-degrading enzyme, which causes cell lysis when externally added to clinical isolates of S. aureus. Another gene, hol15, was identified embedded in the −1 reading frame at the 3′ end of lys16. The deduced Hol15 protein has three putative transmembrane domains, and thus resembles class I holins. An additional candidate holin gene, hol12, was found downstream of the endolysin gene lys16 based on two predicted transmembrane domains of the encoded protein, which is a typical trait of class II holins. The synthesis of either Hol12 or Hol15 resulted in growth retardation of Escherichia coli, and both hol15 and hol12 were able to complement a phage λ Sam mutation. The hol15 gene has a dual start motif beginning with the codons Met1-Lys2-Met3…. Evidence is presented that the hol15 gene encodes a lysis inhibitor (anti-holin) and a lysis effector (actual holin). As depolarization of the membrane converted the anti-holin to a functional holin, these studies suggested that hol15 functions as a typical dual start motif class I holin. The unusual arrangement of the P68 lysis genes is discussed.

Survival of some non-starter bacteria in naturally ripened and enzyme-accelerated Cheddar cheese

1988 ◽  
Vol 55 (4) ◽  
pp. 597-602 ◽  
Author(s):  
Lydia Bautista ◽  
Rohan G. Kroll
Keyword(s):  
Escherichia Coli ◽  
Staphylococcus Aureus ◽  
Enterococcus Faecalis ◽  
Enzyme System ◽  
Cheddar Cheese ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Ripening Period ◽  
Gram Positive Bacteria

SummaryEffects of the addition of a proteinase (Neutrase 1–5S) and a peptidase (aminopeptidase DP-102) as agents for accelerating the ripening of Cheddar cheese on the survival of some non-starter bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coliand aSalmonellasp.) were studied throughout a 4-month ripening period. The enzymes were found to have no significant effect on the survival of the Gram-positive bacteria but some significant effects were observed, at some stages of the ripening period, with the Gram-negative bacteria in that lower levels were recovered from cheeses treated with the enzyme system.

Synthesis and in vitro Biological Activity of New 4,6-Disubstituted 3(2H)-Pyridazinone-acetohydrazide Derivatives

2012 ◽  
Vol 67 (5-6) ◽  
pp. 257-265
Author(s):  
Murat Sukuroglu ◽  
Tijen Onkol ◽  
Fatma Kaynak Onurdağ ◽  
Gulsen Akalın ◽  
M. Fethi Şahin
Keyword(s):  
Biological Activity ◽  
Antimicrobial Activities ◽  
Cytotoxic Activities ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
E Coli ◽  
Preliminary Results ◽  
H Nmr ◽  
Pyridazinone Derivatives

New 3(2H)-pyridazinone derivatives containing a N’-benzyliden-acetohydrazide moiety at position 2 were synthesized. The structures of these newly synthesized compounds were confi rmed by IR, 1H NMR, and MS data. These compounds were tested for their antibacterial, antifungal, antimycobacterial, and cytotoxic activities. The compounds 2-[4-(4-chlorophenyl)- 6-(morpholin-4-yl)-3-oxo-(2H)-pyridazin-2-yl]-N’-(4-tert-butylbenzyliden)acetohydrazide and 2-[4-(4-chlorophenyl)-6-(morpholin-4-yl)-3-oxo-(2H)-pyridazin-2-yl]-N’-(4-chlorobenzyliden) acetohydrazide exhibited activity against both Gram-positive and Gram-negative bacteria. Most of the compounds were active against E. coli ATCC 35218. The preliminary results of this study revealed that some target compounds exhibited promising antimicrobial activities

scholarly journals Membrane Protein Complex ExbB4-ExbD1-TonB1from Escherichia coli Demonstrates Conformational Plasticity

2015 ◽  
Vol 197 (11) ◽  
pp. 1873-1885 ◽  
Author(s):  
Aleksandr Sverzhinsky ◽  
Jacqueline W. Chung ◽  
Justin C. Deme ◽  
Lucien Fabre ◽  
Kristian T. Levey ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Iron Acquisition ◽  
Proton Translocation ◽  
Three Dimensional ◽  
Structural Data ◽  
Structural Features ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Content Type

ABSTRACTIron acquisition at the outer membrane (OM) of Gram-negative bacteria is powered by the proton motive force (PMF) of the cytoplasmic membrane (CM), harnessed by the CM-embedded complex of ExbB, ExbD, and TonB. Its stoichiometry, ensemble structural features, and mechanism of action are unknown. By panning combinatorial phage libraries, periplasmic regions of dimerization between ExbD and TonB were predicted. Using overexpression of full-length His6-taggedexbB-exbDand S-taggedtonB, we purified detergent-solubilized complexes of ExbB-ExbD-TonB fromEscherichia coli. Protein-detergent complexes of ∼230 kDa with a hydrodynamic radius of ∼6.0 nm were similar to previously purified ExbB4-ExbD2complexes. Significantly, they differed in electronegativity by native agarose gel electrophoresis. The stoichiometry was determined to be ExbB4-ExbD1-TonB1. Single-particle electron microscopy agrees with this stoichiometry. Two-dimensional averaging supported the phage display predictions, showing two forms of ExbD-TonB periplasmic heterodimerization: extensive and distal. Three-dimensional (3D) particle classification showed three representative conformations of ExbB4-ExbD1-TonB1. Based on our structural data, we propose a model in which ExbD shuttles a proton across the CM via an ExbB interprotein rearrangement. Proton translocation would be coupled to ExbD-mediated collapse of extended TonB in complex with ligand-loaded receptors in the OM, followed by repositioning of TonB through extensive dimerization with ExbD. Here we present the first report for purification of the ExbB-ExbD-TonB complex, molar ratios within the complex (4:1:1), and structural biology that provides insights into 3D organization.IMPORTANCEReceptors in the OM of Gram-negative bacteria allow entry of iron-bound siderophores that are necessary for pathogenicity. Numerous iron-acquisition strategies rely upon a ubiquitous and unique protein for energization: TonB. Complexed with ExbB and ExbD, the Ton system links the PMF to OM transport. Blocking iron uptake by targeting a vital nanomachine holds promise in therapeutics. Despite much research, the stoichiometry, structural arrangement, and molecular mechanism of the CM-embedded ExbB-ExbD-TonB complex remain unreported. Here we demonstratein vitroevidence of ExbB4-ExbD1-TonB1complexes. Using 3D EM, we reconstructed the complex in three conformational states that show variable ExbD-TonB heterodimerization. Our structural observations form the basis of a model for TonB-mediated iron acquisition.

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