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Bacterial catalytic processes for transformation of metals.

Microorganisms actively participate in the transformation of metals and metalloids by various processes including adsorption, absorption, alkylation, oxidation and reduction reactions. Bacteria of the genera Thiobacillus and Sulfolobus have a chemolithotrophic mode of metabolism and catalyze various metal transformations. These bacteria are primarily involved in oxidation-reduction reactions of metals. Metal sulfides can be either directly oxidized by the microbes or oxidized by ferric iron, an end-product of microbial metabolism. These processes result in solubilization of iron, copper, molyb…

Production of macrophage-derived cytotoxic factor by N-[3-[(carbamoylmethyl)thio]propionylated] neoglycoproteins.

6-Phosphomannosylated bovine serum albumin (Man6P-BSA), a neoglycoprotein endocytosed by macrophages, bearing either 3-(2-pyridyldithio)propionyl or 3-[(carbamoylmethyl)thio]propionyl residues coming from alkylation of thiol residues by iodoacetamide were prepared and tested for their immunomodulator properties. The supernatants of mouse peritoneal macrophages incubated with Man6P-BSA bearing 3-[(carbamoylmethyl)thio]propionyl groups, and by a lesser extent 3-(2-pyridyldithio)propionyl groups, were cytotoxic to L929 cells, suggesting the presence of a tumor necrosis factor like compound. This …

Complex formed by complementary RNA stem-loops and its stabilization by a protein: function of CoIE1 Rom protein.

A small plasmid-specified RNA (RNA I) inhibits formation of the RNA primer for CoIE1 DNA replication by binding to its precursor (RNA II). B … ir loops, forming an RNAase V1-sensitive structure. Rom protects the complex from cleavage and from alkylation of phosphate groups by ethyinitrosourea. A single dimer of Rom binds to the complex by recognizing the structure rather than its exact nucleotide sequence. Rom enhances complex formation by decreasing the rate of dissociation of the complex. Structu …

Dermatitis herpetiformis: 'pH optimum' for the release of potentially antigen-binding IgA fragments from papillary dermis of uninvolved skin by peptic digestion.

In preparations of papillary dermis taken from clinically normal skin of patients with dermatitis herpetiformis (DH), the disappearance of g … ere analysed by sodium-dodecylsulphate (SDS)-polyacrylamide gel electrophoresis after reduction and alkylation followed by electrophoretic transfer to nitrocellulose membranes and subsequent immunochemical detection, IgA-like material corresponding to the alpha-chain part of F (ab)' fragments was found in preparations from DH patients but not in those from c …

Dermatitis herpetiformis: biochemical properties of the granular deposits of IgA in papillary dermis. Characterization of SDS-soluble IgA-like material and potentially antigen-binding IgA fragments released by pepsin.

Granular deposits of IgA in radioactively labeled thin slices of papillary dermis from 4-mm punch biopsies of clinically normal skin from pa … upon immunoprecipitation but could not be deaggregated to alpha- and light chains by reduction and alkylation, suggesting that it was present as irreversible aggregates with itself or with other proteins. Peptic digestion at pH 4.5 released fragments which were precipitated by antibodies to human alpha-chains and had molecular weights similar to the proteol …

Artificial siderophores. 1. Synthesis and microbial iron transport capabilities.

Several di- and trihydroxamate analogues of natural microbial iron chelators have been prepared. The syntheses involved linkage of core stru … 3CN followed by deprotection of the Boc group. The pentyl derivatives 16 and 21 were made by direct alkylation with either benzyl acetohydroxamate or N-carbobenzoxy-O-benzylhydroxylamine. In Escherichia coli RW193 most of the analogues behaved nutritionally as ferrichrome. However, in E. coli AN193, a mutant lacking the ferrichrome receptor, capacity to use …

endo-beta-N-acetilglucosamindase F: эндогликосидаза из Флавобактериума менингосептика, которая кливетирует как высокомантозу, так и сложные гликпротеины.

Мы обнаружили эндогликосидазу, производящуюся флавобактериум менингосептиков. Этот фермент, названный эндо Ф, кликанирует как высокомантозы, так и сложные типы, связанные через апарагин с белковым позвоночником. Данные свидетельствуют о том, что декольте происходит через гидролиз гликозидной связи структуры ядра N, N'-диацетилкитобиозы, прилегающей к апарагину, аналогично тому, как это происходит с эндо H и эндо D. Была отмечена экстремальная вариативность наличия этого участка декольтеинов у связанных с N гликпротеинов. Гликопротеины ретровируса, лимфоцитного хориоменингита, вируса Пичинда и

Совпадение в аннотации оригинала
We have detected an endoglycosidase activity produced by Flavobacterium meningosepticum. This enzyme, named endo F, cleaves glycans of both … in, immunoglobulin G, and influenza virus hemagglutinin became susceptible only after reduction and alkylation or when cleavage was performed in the presence of 1% 2-mercaptoethanol. Endo F should prove useful in the study of glycans and protein backbones as discrete entities and for defining the nature of the glycan-protein interface.

Treatment patterns and outcomes of patients with relapsed or refractory follicular lymphoma receiving three or more lines of systemic therapy (LEO CReWE): a multicentre cohort study.

BACKGROUND: Novel therapies for relapsed or refractory follicular lymphoma are commonly evaluated in single-arm studies without formal comparison with other treatments or historical controls. Consequently, rigorously defined treatment outcomes informing expectations for novel therapeutic strategies in this population are sparse. To inform outcome expectations, we aimed to describe treatment patterns, survival outcomes, and duration of response in patients with relapsed or refractory follicular lymphoma receiving three or more lines of systemic therapy. METHODS: In this multicentre cohort stud

Ifosfamide-Induced Encephalopathy in a Very Young Child With Rhabdomyosarcoma: Case Report and Literature Review.

PURPOSE: Ifosfamide is an alkylating agent used against a variety of pediatric solid tumors; ifosfamide-induced encephalopathy (IIE) is a potential life-threatening event that may occur within 24 to 48 hours after its administration. Hepatic bioactivation of ifosfamide is mediated by CYP3A4 and CYP2B6; their genetic polymorphisms may alter its metabolism, thereby promoting IIE. METHODS: Here we report our experience of a 14-month-old baby affected by rhabdomyosarcoma of the bladder, who developed a severe neurotoxicity after the first dose of ifosfamide and successfully recovered after prompt

Design and Synthesis of Bendamustine-Carbonic Anhydrase Inhibitors with Antiproliferative Effects in Clear Cell Renal Cell Carcinoma.

Human carbonic anhydrase IX (hCA IX) is markedly overexpressed in clear cell renal cell carcinoma and plays a key role in establishing an acidic tumor microenvironment associated with intrinsic chemoresistance. Extracellular acidification limits the uptake and efficacy of several cytotoxic agents, including bendamustine, a bifunctional alkylating agent whose activity depends on intracellular accumulation and DNA cross-link formation. Herein, we report the design and synthesis of novel bendamustine-carbonic anhydrase inhibitor (CAI) hybrids aimed at combining CA IX targeting with DNA-damaging a

P-Chiral Organophosphorus Compounds: Synthesis, Mechanism, and Applications.

The enantioselective synthesis of P-stereogenic compounds has emerged as a central focus in modern asymmetric catalysis, driven by their piv … c substitution at P(V) centers, cyclization, C-H activation (CHA), phenolic -OH activation, and P-O alkylation/arylation. Mechanistic insights into these transformations have been discussed, along with the derivatization of P-chiral products and their applications in catalysis, L design, and bioactive molecule synthesis. This comprehensive overview shall ser …

Catalytic Enantioselective Friedel-Crafts Allenylation.

The first enantioselective Friedel-Crafts (FC) allenylation reaction for the creation of central chirality is developed under cooperative Ir … benzylic stereocenter. Judicious synthetic elaborations not only lead to formal enantioselective FC alkylation products of less electron-rich arenes but also of substituted arenes in ortho- and even meta-selective fashion. An intramolecular version of this FC allenylation is shown to proceed with promising enantioselectivity under the same catalytic conditio …

A Modular Dual-Catalytic Aryl-Chlorination of Alkenes.

Alkyl chlorides are a class of versatile building blocks widely used to generate C(sp3)-rich scaffolds through transformation such as nucleophilic substitution, radical addition reactions and metal-catalyzed cross-coupling processes. Despite their utility in the synthesis of high-value functional molecules, distinct methods for the preparation of alkyl chlorides are underrepresented. Here, we report a visible-light-mediated dual catalysis strategy for the modular synthesis of highly functionalized and structurally diverse arylated chloroalkanes via the coupling of diaryliodonium salts, alkenes

Photo-on-Demand In Situ One-Pot Synthesis of Carbonate Esters from Tetrachloroethylene.

The present study reports a novel one-pot synthesis of carbonate esters with photo-oxidized tetrachloroethylene (TCE). Acyclic and cyclic alkyl carbonate esters could be synthesized through base-promoted condensation reactions of alcohols with the photo-oxidized TCE that was prepared by irradiation with UV-C or visible light under O2 or O2/Cl2 (∼4%) bubbling, respectively. Cyclic carbonate esters could also be synthesized from a solution of TCE and the ethylene glycol derivative by irradiation of UV-C light under O2 bubbling. With respect to the reaction mechanism, the photochemical oxidation

A general copper-catalysed enantioconvergent C(sp3)-S cross-coupling via biomimetic radical homolytic substitution.

Although α-chiral C(sp3)-S bonds are of enormous importance in organic synthesis and related areas, the transition-metal-catalysed enantioselective C(sp3)-S bond construction still represents an underdeveloped domain probably due to the difficult heterolytic metal-sulfur bond cleavage and notorious catalyst-poisoning capability of sulfur nucleophiles. Here we demonstrate the use of chiral tridentate anionic ligands in combination with Cu(I) catalysts to enable a biomimetic enantioconvergent radical C(sp3)-S cross-coupling reaction of both racemic secondary and tertiary alkyl halides with highl

Solvent-free visible-light-mediated α-phosphorylation and Csp3-H activation of tertiary and secondary amines at room temperature in the presence of cadmium sulfide nanophotocatalyst.

Recently, the synthesis of organic compounds via Csp3-H activation is an important target for organic and medicinal chemists. On the other hand, visible-light-mediated organic synthesis is an attractive method, which is dependent on the capability of the reagent or photocatalyst to take up solar energy. Thus, the discovery and development of novel, Milde, simple, and effective manners using visible-light-induced photocatalysts have gained great interest in synthetic organic chemistry. Herein, cadmium sulfide (CdS) nanophotocatalyst has been successfully used for the reaction of tertiary and se

Synthesis, Characterization, and Reactivity of Tris(imido)chromium(VI) Complexes.

Multiple tris(imido)chromium(VI) complexes, including neutral and ionic compounds, have been synthesized and characterized. (tBuN)2Cr(NHtBu)Cl can be deprotonated by KN(SiMe3)2, yielding K[(tBuN)3CrCl]. This tris(imido) anion undergoes nucleophilic substitution by PPh3 and tBuNH2 to form (tBuN)3Cr(PPh3) and (tBuN)2Cr(NHtBu)2, respectively. (tBuN)2Cr(NHtBu)2 loses one amido proton to form K[(tBuN)3Cr(NHtBu)] upon reaction with KN(SiMe3)2. The imido ligands of K[(tBuN)3CrCl] and (tBuN)3Cr(PPh3) are attacked by the electrophile MeI to produce (tBuN)2Cr(NMetBu)Cl and (tBuN)2Cr(NMetBu)I, respective

Direct Correlation of Surface Tension and Surface Composition of Ionic Liquid Mixtures-A Combined Vacuum Pendant Drop and Angle-Resolved X-ray Photoelectron Spectroscopy Study.

We investigated the surface tension and surface composition of various mixtures of the two ionic liquids (ILs) 1-methyl-3-octyl-imidazolium hexafluorophosphate [C8C1Im][PF6] and 1,3-bis(polyethylene glycol)imidazolium iodide [(mPEG2)2Im]I in the temperature range from 230 to 370 K under ultraclean vacuum conditions. The surface tension was measured using a newly developed apparatus, and the surface composition was determined by angle-resolved X-ray photoelectron spectroscopy (ARXPS). In the pure ILs, the alkyl chains of [C8C1Im][PF6] and the PEG chains of [(mPEG2)2Im]I are enriched at the IL/v

Facile Synthesis of Functionalised Hyperbranched Polymers for Application as Novel, Low Viscosity Lubricant Formulation Components.

A novel, previously unreported, method for synthesising hyperbranched (HB) materials is detailed. Their use as additives to produce lubricant formulations that exhibit enhanced levels of wear protection and improved low-temperature oil viscosity and flow is also reported. The lubricant formulations containing HB additives were found to exhibit both significantly lower viscosities and improved in-use film-forming properties than the current industry standard formulations. To achieve this, alkyl methacrylate oligomers (predominantly dimers and trimers) were synthesised using catalytic chain tran

A DFT/TDDFT Investigation on Fluorescence and Electronic Properties of Chromone Derivatives.

The development of quick and precise detection technologies for active compounds in vivo is critical for disease prevention, diagnosis and pathological investigation. The fluorescence signal of the fluorophore usually defines the probe's sensitivity to the chemical being examined. Many natural compounds containing flavone and isoflavone scaffolds exhibit a certain amount fluorescence, albeit with poor fluorescence quantum yields. Therefore, we used density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations to investigate the fluorescence characteristics o