Identification of a Bacteria-produced Benzisoxazole with Antibiotic Activity against Multi-drug Resistant Acinetobacter baumannii

The emergence of multi-drug resistant pathogenic bacteria represents a serious and growing threat to national healthcare systems. Most pressing is an immediate need for the development of novel antibacterial agents to treat Gram-negative multi-drug resistant infections, including the opportunistic, hospital-derived pathogen, Acinetobacter baumannii. Herein we report a naturally occurring 1,2-benzisoxazole with minimum inhibitory concentrations as low as 6.25 μg ml−1 against clinical strains of multi-drug resistant A. baumannii and investigate its possible mechanisms of action. This molecule represents a new chemotype for antibacterial agents against A. baumannii and is easily accessed in two steps via de novo synthesis. In vitro testing of structural analogs suggest that the natural compound may already be optimized for activity against this pathogen. Our results demonstrate that supplementation of 4-hydroxybenzoate in minimal media was able to reverse 1,2-benzisoxazole’s antibacterial effects in A. baumannii. A search of metabolic pathways involving 4-hydroxybenzoate coupled with molecular modeling studies implicates two enzymes, chorismate pyruvate-lyase and 4-hydroxybenzoate octaprenyltransferase, as promising leads for the target of 3,6-dihydroxy-1,2-benzisoxazole

Оптимизация конструкции захвата для детали «Барабан»

Грузозахватные приспособления обычно применяются при производстве работ по подъему и перемещению грузов с применением грузоподъемных машин. Использование приспособлений позволяет реализовать максимальное удобство и безопасность производственного процесса. Грузозахватные приспособления конструируются для определенного этапа технологического процесса, для конкретного изделия. При проектировании таких приспособлений необходимо учитывать основные показатели оптимальности конструкции: прочность, надежность, простота, удобство и безопасность при эксплуатации, эргономичность. Кроме того, нужно стремиться к наименьшей массе и, соответственно, металлоемкости захвата. Конструкция грузозахватного приспособления, в основном, будет зависеть от назначенных технологом поверхностей, за которые можно крепиться и от максимальной высоты подъема крюка крана. В статье описана задача по конструированию захвата для детали «Барабан¬ в новом технологическом процессе. Рассмотрена конструкция существующего захвата, взятого за прототип. Приведен анализ различных вариантов конструктивных решений, созданных в процессе проектирования. Выбран вариант конструкции захвата, который в наибольшей степени соответствует требованиям технического задания. Конструкция этого модернизированного приспособления представляет собой захват с тремя лапами, удерживающими деталь, и подвес в виде траверсы. Разработанная конструкторская документация утверждена производством и отделом промышленной безопасности

Magnetocapacitance in La0.7Sr0.3MnO3/Pb(Zr0.2Ti0.8)O3/La0.7Sr0.3MnO3 multiferroic heterostructures

Measurements of the magnetocapacitance effect in epitaxial La0.7Sr0.3MnO3/Pb(Zr0.2Ti0.8)O3/La0.7Sr0.3MnO3 heterostructures have been performed using a quasi-static method. Through capacitance-voltage measurements carried out under variable magnetic field it has been found that the magneto-capacitance depends on the orientation of the ferroelectric polarization. The value of magneto-capacitance can be as high as 1% in the voltage range near the ferroelectric coercive field. This has been attributed to a variation of the apparent built-in voltage of the PZT-LSMO Schottky barriers on applied magnetic field

5-Bromo-4-(3,5-dibromo-2-hydroxyphenyl)-2-(piperidin-1-yl)-1,3-dithiol-2-ylium bromide

In the title salt, C14H13Br3NOS2+·Br−, synthesized by bromination of mesoionic 2-[2-(piperidin-1-yl)-1,3-dithiol-2-ylium-4-yl]phenolate in glacial acetic acid, the dihedral angle between the 1,3-dithiolium ring and the phenolic substituent ring is 45.9 (3)° due to the steric influence of the ortho-Br group on the 1,3-dithiolium ring. The piperidine ring adopts a chair conformation. In the crystal, the cation and anion are linked by an O—H...Br hydrogen bond

New Lanthanide Alkynylamidinates and Diiminophosphinates

This contribution reports the synthesis and structural characterization of several new lithium and lanthanide alkynylamidinate complexes. Treatment of PhC≡CLi with N,N′-diorganocarbodiimides, R–N=C=N–R (R = iPr, Cy (cyclohexyl)), in THF or diethyl ether solution afforded the lithium-propiolamidinates Li[Ph–C≡C–C(NCy)2] S (1: R = iPr, S = THF; 2: R = Cy, S = THF; 3: R = Cy, S = Et2O). Single-crystal X-ray diffraction studies of 1 and 2 showed the presence of typical ladder-type dimeric structures in the solid state. Reactions of anhydrous LnCl3 (Ln = Ce, Nd, Sm or Ho) with 2 in a 1:3 molar ratio in THF afforded a series of new homoleptic lanthanide tris(propiolamidinate) complexes, [Ph–C≡C–C(NCy)2]3Ln (4: Ln = Ce; 5: Ln = Nd; 6: Ln = Sm; 7: Ln = Ho). The products were isolated in moderate to high yields (61%–89%) as brightly colored, crystalline solids. The chloro-functional neodymium(III) bis(cyclopropylethynylamidinate) complex [{c-C3H5–C≡C–C(NiPr)2}2Ln(µ-Cl)(THF)]2 (8) was prepared from NdCl3 and two equiv. of Li[c-C3H5–C≡C–C(NiPr)2] in THF and structurally characterized. A new monomeric Ce(III)-diiminophosphinate complex, [Ph2P(NSiMe3)2]2Ce(µ-Cl)2Li(THF)2 (9), has also been synthesized in a similar manner from CeCl3 and two equiv. of Li[Ph2P(NSiMe3)2]. Structurally, this complex resembles the well-known “ate” complexes (C5Me5)2Ln(µ-Cl)2Li(THF)2. Attempts to oxidize compound 9 using trityl chloride or phenyliodine(III) dichloride did not lead to an isolable cerium(IV) species

4-Bromo-2-[5-methyl-2-(morpholin-4-yl)-1,3-thiazol-4-yl]phenol

In the title compound, C14H15BrN2O2S, synthesized by the reaction of the corresponding phenacyl thiocyanate with morpholine, the dihedral angle between the 1,3-thiazole ring and the phenolic substituent ring is 23.46 (10)° as a result of the steric influence of the ortho-methyl group on the thiazole ring. A strong intramolecular phenolic O—H...N hydrogen bond is present in the molecule. In the crystal, a weak C—H...Ophenol hydrogen bond gives rise to chains lying parallel to [20-1]. A short intermolecular Br...Omorpholine interaction is also present [3.1338 (19) Å]