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11.
Benedetta Fois Žiga Skok Prof. Dr. Tihomir Tomašič Prof. Dr. Janez Ilaš Prof. Dr. Nace Zidar Prof. Dr. Anamarija Zega Prof. Dr. Lucija Peterlin Mašič Petra Szili Gábor Draskovits Ákos Nyerges Dr. Csaba Pál Prof. Dr. Danijel Kikelj 《ChemMedChem》2020,15(3):265-269
The emergence of multidrug-resistant bacteria is a global health threat necessitating the discovery of new antibacterials and novel strategies for fighting bacterial infections. We report first-in-class DNA gyrase B (GyrB) inhibitor/ciprofloxacin hybrids that display antibacterial activity against Escherichia coli. Whereas DNA gyrase ATPase inhibition experiments, DNA gyrase supercoiling assays, and in vitro antibacterial assays suggest binding of the hybrids to the E. coli GyrA and GyrB subunits, an interaction with the GyrA fluoroquinolone-binding site seems to be solely responsible for their antibacterial activity. Our results provide a foundation for a new concept of facilitating entry of nonpermeating GyrB inhibitors into bacteria by conjugation with ciprofloxacin, a highly permeable GyrA inhibitor. A hybrid molecule containing GyrA and GyrB inhibitor parts entering the bacterial cell would then elicit a strong antibacterial effect by inhibition of both the GyrA and GyrB subunits of DNA gyrase and potentially slow bacterial resistance development. 相似文献
12.
V. M. Nace 《Journal of the American Oil Chemists' Society》1996,73(1):1-8
Previous studies have shown that polyoxybutylene surfactant hydrophobes are less polar than polyoxypropylene hydrophobes.
Polyoxyalkylene hydrophobes can be modified by ethoxylation to give terminal polyoxyethylene block hydrophilic groups. Polyoxybutylene/polyoxyethylene
copolymer surfactants exhibit differentiated interfacial tensions, and wetting and foaming properties when compared to structurally
equivalent polyoxypropylene/polyoxyethylene copolymers. There have been no reported comparisons, however, of polyoxybutylene/polyoxyethylene
copolymers and polyoxypropylene/polyoxyethylene analogues in terms of fundamental parameters, such as critical micelle concentration,
area per molecule at the interface, efficiency, and effectiveness. In one phase of this work, four polyoxybutylene/polyoxyethylene
block copolymer surfactants were compared to structurally analogous polyoxypropylene/polyoxyethylene materials. Findings showed
that polyoxybutylene/polyoxyethylene copolymers exhibited enhanced cotton wetting and lower surface and interfacial tensions
compared to polyoxypropylene/polyoxyethylene analogues. Polyoxybutylene-based surfactants were typically one order of magnitude
better in their ability to reduce surface tension at interface saturation. Polyoxybutylene/polyoxyethylene copolymers pack
more efficiently at the interface, as evidenced by a smaller area per molecule at the interface. Critical micelle concentration
values were also lower for polyoxybutylene/polyoxyethylene copolymers. A second phase of experiments focused on the surface
activity of polyoxypropylene/polyoxyethylene triblock copolymers with higher molecular weight hydrophobes. Enhanced surface
activity was found when compared to lower-molecular weight polyoxypropylene/polyoxyethylene copolymers. 相似文献
13.
V. M. Nace R. H. Whitmarsh M. W. Edens 《Journal of the American Oil Chemists' Society》1994,71(7):777-781
Block copolymer surfactants, made from 1,2-butylene oxide (BO), propylene oxide (PO) and ethylene oxide (EO), exhibit wide
ranges of properties and performance. In particular, BO/EO block copolymers exhibit improved surfactant performance with respect
to PO/EO analogs. One interesting difference between these two classes of surfactants is the EO capping efficiency of polyoxypropylene
(POP) vs. polyoxybutylene (POB) hydrophobe secondary hydroxyl groups. In this regard, nuclear magnetic resonance measurements
have shown that POP secondary diols react more readily with EO than POB diols. For the case of ethoxylated POB polymers, the
amount of unethoxylated secondary hydroxyl is proportional to the average length of the polyoxyethylene (POE) blocks. Differential
scanning calorimetry was used to observe crystallinity of POE blocks. For a given POB hydrophobe molecular weight and weight
percentage EO, surfactant performance properties can be augmented by affecting POE block length in the ethoxylation process. 相似文献
14.
Polyglycol nonionic surfactants are widely used in industrial and consumer products. Two classes of these surfactants, made
from selected combinations of 1,2-butylene oxide, propylene oxide and ethylene oxide, were compared to alcohol ethoxylate
(AE) and nonyl phenol ethoxylate nonionic surfactants in this study. Polyglycol copolymers consisted of either a polypropylene
glycol (PPG) or polybutylene glycol (PBG) central hydrophobe. Ethoxylation of the hydrophobes produced polyethylene glycol
hydrophilic blocks. Differences in hydrophobe polarity were determined by inverse gas chromatography (IGC). IGC is a useful
analytical method by which the physical and chemical characteristics of a material are studied. The stationary surfactant
material under study was coated onto an inert support and used as the packing for the column. A probe mixture, containing
simple organic molecules of varying polarity, was injected, and the retention characteristics were measured. The retention
characteristics of the standard probe mixture were used to reveal relative polarity information about the stationary surfactant
coatings. Polarities of the four hydrophobes were (in decreasing order): PPG, PBG, nonyl phenyl and fatty alkyl. Comparisons
were then made between the calculated hydrophile-lipophile balance values and polarity indices of the hydrophobes and their
ethoxylates. The effects of hydroxyl groups on polarity were also studied and quantified. 相似文献
15.
Dritan Nace Linh Nhat Doan Olivier Klopfenstein Alfred Bashllari 《Computers & Operations Research》2008
In this paper, we provide a study of Max–Min Fair (MMF) multi-commodity flows and focus on some of their applications to multi-commodity networks. We first present the theoretical background for the problem of MMF and recall its relations with lexicographic optimization as well as a polynomial approach for achieving leximin maximization. We next describe two applications to telecommunication networks, one on routing and the second on load-balancing. We provide some deeper theoretical analysis of MMF multi-commodity flows, show how to solve the lexicographically minimum load network problem for the link load functions most frequently used in telecommunication networks. Some computational results illustrate the behavior of the obtained solutions and the required CPU time for a range of random and well-dimensioned networks. 相似文献
16.
Tihomir Tomašić Nace Zidar Andreja Kovač Dr. Samo Turk Mihael Simčič Didier Blanot Dr. Manica Müller‐Premru Prof. Dr. Metka Filipič Prof. Dr. Simona Golič Grdadolnik Prof. Dr. Anamarija Zega Prof. Dr. Marko Anderluh Prof. Dr. Stanislav Gobec Prof. Dr. Danijel Kikelj Prof. Dr. Lucija Peterlin Mašič Prof. Dr. 《ChemMedChem》2010,5(2):286-295
Mur ligases participate in the intracellular path of bacterial peptidoglycan biosynthesis and constitute attractive, although so far underexploited, targets for antibacterial drug discovery. A series of hydroxy‐substituted 5‐benzylidenethiazolidin‐4‐ones were synthesized and tested as inhibitors of Mur ligases. The most potent compound 5 a was active against MurD–F with IC50 values between 2 and 6 μm, making it a promising multitarget inhibitor of Mur ligases. Antibacterial activity against different strains, inhibitory activity against protein kinases, mutagenicity and genotoxicity of 5 a were also investigated, and kinetic and NMR studies were conducted. 相似文献
17.
In this work we study a routing scheme combined with an end-to-end rerouting procedure. We focus in particular on a new rerouting strategy called Shared Robust Rerouting (ShRR). This strategy combines three other restoration techniques, namely path diversity, end-to-end rerouting with stub release and global rerouting, in order to achieve cost-effectiveness. Computational results on the bandwidth overhead required by the proposed scheme are provided, as well as a comparison with some conventional restoration schemes. 相似文献
18.
In this paper, we consider the max-min fair resource allocation problem as applied to elastic flows. We are interested in computing the optimal max-min fair rate allocation. The proposed approach is a linear programming based one and allows the computation of optimal routing paths with regard to max-min fairness, in stable and known traffic conditions. We consider non-bounded access rates, but we show how the proposed approach can handle the case of upper-bounded access rates. A proof of optimality and some computational results are also presented 相似文献
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20.
Viviana Gatta Prof. Tihomir Tomašič Prof. Janez Ilaš Prof. Nace Zidar Prof. Lucija Peterlin Mašič Michaela Barančoková Prof. Rok Frlan Prof. Marko Anderluh Prof. Danijel Kikelj Prof. Päivi Tammela 《Chembiochem : a European journal of chemical biology》2020,21(13):1918-1922
Quorum sensing (QS), a bacterial communication strategy, has been recognized as one of the control mechanisms of virulence in bacteria. Thus, targeting QS offers an interesting opportunity to impair bacterial pathogenicity and develop antivirulence agents. Aiming to enhance the discovery of QS inhibitors, we developed a bioreporter Escherichia coli JW5505 pET-Plsrlux and set up a cell-based assay for identifying inhibitors of autoinducer-2 (AI-2)-mediated QS. A comparative study on the performance of target- versus cell-based assays was performed, and 91 compounds selected with the potential to target the ATP binding pocket of LsrK, a key enzyme in AI-2 processing, were tested in an LsrK inhibition assay, providing 36 hits. The same set of compounds was tested by the AI-2-mediated QS interference assay, resulting in 24 active compounds. Among those, six were also found to be active against LsrK, whereas 18 might target other components of the pathway. Thus, this AI-2-mediated QS interference cell-based assay is an effective tool for complementing target-based assays, yet also stands as an independent assay for primary screening. 相似文献