ctive: The development of a fast and reliable method for the quantitative evaluation of steroid hormones is very relevant for scientific and clinical research. The goal of this study was to develop a new universal method for the synthesis of fluorescent tracers from carbonyl-containing biomolecules by oxime ligation. Methods: A method for the synthesis of ketosteroid oxime conjugates with a fluorescein (6-FAM) derivative connected via a short bifunctional aminooxypropyl linker is proposed. Oxime stereoisomers were separated by preparative RP TLC and HPLC. The conjugates were used as tracers for the fluorescence polarization immunoassay (FPIA) method with monoclonal antibodies. Results and Discussion: Parameters of the binding of the tracers with monoclonal antibodies (mAbs) to progesterone were studied. The tracers demonstrated high efficiency for the measurement of steroid hormone concentration, with the detection limit of progesterone being lower than that for a previously described analog. The Z -isomer was found to be more sensitive in FPIA compared to the E -isomer. Conclusions: Thus, we have developed an effective and universal approach to the synthesis of fluorescent conjugates with a linker length optimal for immunoassay, which improves their analytical characteristics and simplifies their preparation. The synthesized compounds have potential for practical use in clinical diagnostics and the analysis of environmental objects.

The persisting presence of opportunistic pathogens like Pseudomonas aeruginosa poses a significant threat to many immunocompromised cancer patients with pulmonary infections. This review highlights the complexity of interactions in the host’s defensive eicosanoid signaling network and its hijacking by pathogenic bacteria to their own advantage. Human lipoxygenases (ALOXs) and their mouse counterparts are integral elements of the innate immune system, mostly operating in the pro-inflammatory mode. Taking into account the indispensable role of inflammation in carcinogenesis, lipoxygenases have counteracting roles in this process. In addition to describing the structure-function of lipoxygenases in this review, we discuss their roles in such critical processes as cancer cell signaling, metastases, death of cancer and immune cells through ferroptosis, as well as the roles of ALOXs in carcinogenesis promoted by pathogenic infections. Finally, we discuss perspectives of novel oncotherapeutic approaches to harness lipoxygenase signaling in tumors.

A method for the synthesis of ketosteroid oxime conjugates with a fluorescein (6-FAM) derivative connected via a short bifunctional aminooxypropyl linker is proposed. The conjugates were used as tracers for fluorescence polarization immunoassay (FPIA) with monoclonal antibodies. Stereoisomers by the oxime group were separated by preparative RP TLC and HPLC and tested in the FPIA method. Binding parameters of of tracers with monoclonal antibodies (mAbs) to progesterone were studied. Tracers showed high efficiency in the analysis of steroid hormones, the detection limit of progesterone being lower than that for a previously described analog. The Z-isomer was found to be more sensitive in the FPIA analysis compared to the E-isomer.

Eine neue Familie von Lipoglycopeptid-Antibiotika mit einzigartigen strukturellen Merkmalen und ausgeprägter Aktivität gegen Gram-positive Bakterien wird von Stanislav S. Terekhov, Zakhar O. Shenkarev, Vladimir A. Korshun et al. in ihrem Forschungsartikel auf S. 18842 vorgestellt. Gausemycine sind intrinsisch fluoreszierende Verbindungen mit einem einzigartigen Modus der antibakteriellen Wirkung. Die Analyse des Biosynthese-Genclusters entschlüsselte eine ungewöhnliche Enzymologie, die an der Bildung einer bisher unbekannten nicht-proteinogenen Aminosäure beteiligt ist.

We report a novel family of natural lipoglycopeptides produced by Streptomyces sp. INA-Ac-5812. Two major components of the mixture, named gausemycins A and B, were isolated, and their structures were elucidated. The com-pounds are cyclic peptides with a unique peptide core and several remarkable structural features, including unusual posi-tions of D-amino acids, lack of the Ca2+-binding Asp-X-Asp-Gly (DXDG) motif, tyrosine glycosylation with arabinose, presence of 2-amino-4-hydroxy-4-phenylbutyric acid (Ahpb) and chlorinated kynurenine (ClKyn), N-acylation of the or-nithine side chain. These major components of the peptide antibiotic family have pronounced activity against Gram-positive bacteria. The mechanism of action of gausemycins was explored by a number of methods, showing significant differences compared to glycopeptides and related lipopeptides. Gausemycins exhibit only slight Ca2+-dependence of an-timicrobial activity and induce no pore formation at low concentrations. Moreover, there is no detectable accumulation of cell wall biosynthesis precursors under treatment with gausemycins.

Antibiotics produced by symbiotic microorganisms were previously shown to be of crucial importance for ecological communities, including ants. Previous works on ant–actinobacteria symbiosis are mainly focused on farming ants, which use antifungal microbial secondary metabolites to control pathogens in their fungal gardens. In this work, we studied microorganisms associated with carpenter ant Camponotus vagus. Pronounced antifungal activity of isolated actinobacteria strain A10 was found to be facilitated by biosynthesis of the antimycin A complex, consisting of small hydrophobic depsipeptides with high antimicrobial and cytotoxic activity. The actinomycete strain A10 was identified as Streptomyces albidoflavus. We studied the antagonistic activity of strain A10 against several entomopathogenic microorganisms. The antifungal activity of this strain potentially indicates a defensive symbiosis with the host ant, producing antimycins to protect carpenter ants against infections. The nature of this ant-microbe association however remains to be established.

The study of an archived sample of crystallomycin complex using HPLC, ESI HRMS, and 2D NMR showed that two major components of the antibiotic, compounds 1 and 2, are lipopeptides having the same peptide core, Asp1-cyclo(Dab2-Pip3-MeAsp4-Asp5-Gly6-Asp7-Gly8-Dab9-Val10-Pro11-), N-acylated either with Δ3-iso-tetradecenoyl or Δ3-anteiso-pentadecenoyl that are identical to aspartocins C and B, respectively. According to the 2D NMR study, compound 2 in DMSO solution exists as a mixture of four conformers. The producing strain was identified as Streptomyces griseorubens. Compounds 1 and 2 have considerable Ca2+-dependent activity against Gram-positive bacteria including five MRSA strains.

The review will cover main classes of 3,4-dihydroisocoumarin-derived natural and bioactive compounds with main focus on antibiotics, amicoumacins and xenocoumacins. The 3,4-dihydroisocoumarin natural compounds were reviewed many years ago (Hill, 1986 [2]; McInerney and Taylor, 1995 [7]). The recent short account on amicoumacins is in Chinese and does not contain any synthetic data (Han et al., 2013 [23]). Amicoumacins A, B, and C, although discovered in the early 1980s, recently attracted attention of researchers again. These compounds have antibacterial, antiinflammatory, antiulcer (gastroprotective), herbicidal, and cytotoxic activity. Their potent antiulcerogenic action without any anticholinergic and antihistaminergic effects is the most attractive feature of this unique class of drugs. Recently, the researchers made insight into 3,4-dihydroisocoumarin and amicoumacin biosynthesis (Li et al., 2012, 2015 , ; Reimer et al., 2011 [46]; Sun et al., 2012 [80]). An impressive progress is achieved in the chemical synthesis of 3,4-dihydroisocoumarin antibiotics (Enomoto and Kuwahara, 2009, 2009 , ; Rao et al., 2014 [99]; Suzuki et al., 2015 [100]). New amicoumacin-related bioactive compounds are isolated and characterized (Bai et al., 2014 [45]; Liu et al., 2013 [42]). Recent biochemical studies revealed that amicoumacin belongs to a new class of protein synthesis inhibitors that binds to the ribosome (Lama et al., 2012 [51]; Polikanov et al., 2014 [81]). Thus, studies on amicoumacin family members undergo a renaissance, and an account on their recent chemistry and biology would be useful and well timed.

Two new natural compounds, astolides A,B, were isolated from Streptomyces hygroscopicus collected from the alkaline soil obtained from Saratov region, Russia. The structures were elucidated by interpretation of UV spectroscopic, MS, 1D and 2D NMR data. The relative configurations were determined by analysis of NOESY/ROESY spectra and coupling constants. The isolated compounds were evaluated for their inhibitory activity against bacteria, fungi and yeasts and showed pronounced antifungal activity. Both compounds are noticeably cytotoxic, being active against doxorubicin-resistant human leukemia cell line.

The synthesis of phosphoramidite reagents and solid-phase supports based on hydroxyprolinol for the introduction of the residues of biotin, lipoic acid, amino groups, and terminal acetylene groups at different positions of the oligonucleotide chain has been described. The efficiency of the reagents and supports has been confirmed by the synthesis of the corresponding modified oligonucleotides.

1-Phenylethynylpyrene fluorophore (1-PEPy) has long-wavelength shifted emission and higher photostability compared to pyrene, retaining, however, pyrene's ability to form excimers. Here we report the synthesis of 2′-O-[3(and 4)-(pyren-1-ylethynyl)benzyl]-uridines and their tandem incorporation into deoxyribo- and 2′-O-Me-ribo-oligonucleotide probes. Excimer forming probes of type NN … NNXXNN … NN (X = 2′-O-[meta(or para)-(pyren-1-ylethynyl)-benzyl]uridine) containing two adjacent fluorescent nucleosides within an oligonucleotide are available in four types (meta-meta; para-meta; meta-para; para-para). Both DNA (N = deoxyribonucleotides) and 2′-O-Me-RNA (N = 2′-O-Me-ribo-nucleotides) probes were synthesized and their hybridization with complementary and singly mismatched DNA and RNA was studied. Several probes show a dramatic response of their excimer-to-monomer intensity ratio upon hybridization. Remarkably, most spectacular fluorescence changes were demonstrated for probes with para-meta and meta-para combination within 2′-O-Me-ribo-oligonucleotides. Using excimer forming probes, three natural SNP in Helicobacter pylori 23S RNA gene (A2144G, A2143G, A2143C) and the wild type gene can be distinguished.

2(5)-Substituted 4-hydroxy-3,4-diphenylcyclopent-2-en-1-ones easily react with 2.5 molar excess of maleic anhydride to give 1(4)-substituted 7,8-diphenylbicyclo[2.2.2] oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydrides containing alkyl groups at bridgehead of the bicycle. The stereochemistry of the obtained bicyclic bis-anhydrides was determined to be syn-syn.

Molecular beacons carrying JOE dye (4′,5′-dichloro-2′,7′-dimethoxy-6-carboxyfluorescein) on a rigid or flexible linker and one or two BHQ1 quenchers have been prepared and tested in real-time PCR using Fusarium avenaceum elongation factor 1α DNA template. The probes were different in their structures (loop size and stem length), linkers for dye attachment (6-aminohexanol or trans-4-aminocyclohexanol), quencher composition (single and double BHQ1) to elucidate the influence of all these features. Fluorogenic properties of the probes were studied and compared to those of FAM (fluorescein)-based probes. All the factors – stem length, JOE vs FAM, rigid vs flexible linker, single vs double quencher – appeared to play a considerable role in the probe's fluorescent properties and determine the usability of the probe at two different temperatures of fluorescence detection (55°С and 64°С).

Branching points in DNA nanostructures are usually 3- or 4-way junctions maintained by Watson-Crick non-covalent interactions. However, covalently bound DNA stars could improve the diversity, strength and integrity of DNA nanoscale constructions. We report here the convenient synthesis of 3- and 4-fold pentaerythritol-based azides and their use for the assembly of branched conjugates containing the same or different oligonucleotides (ODNs) and/or fluorescent dyes by stoichiometry controlled copper (I) catalyzed azide alkyne cycloaddition (CuAAC) functionalization.

Detection of aminoglycoside antibiotics by MS or HPLC is complicated, because a) carbohydrate molecules have low ionization ability in comparison with other organic molecules (particularly in MALDI-MS), and b) the lack of aromatics and/or amide bonds in the molecules makes common HPLC UV-detectors useless. Here, we report on the application of a previously developed method for amine derivatization with tris(2,6-dimethoxyphenyl)carbenium ion to selective modification of aminoglycoside antibiotics. Only amino groups bound to primary carbons get modified. The attached aromatic residue carries a permanent positive charge. This makes it easy to detect aminoglycoside antibiotics by MS-methods and HPLC, both as individual compounds and in mixtures.

A concentrate with the antimicrobial activity has been isolated from the culture broth of Streptomyces roseoflavus INA-Ac-5812. Its further fractionation by reversed-phase HPLC has resulted in six fractions. It has been established by MALDI-TOF and ESI-MS n precision mass-spectrometry methods that the main components of the complex antibiotic are several closely related compounds, presumably of a glycopeptide nature. The fraction containing an individual component with a mass of 1845.788 Da has been characterized by UV/Vis absorbance and fluorescence spectra, amino acid analysis, and derivatization with tris(2,6-dimethoxyphenyl)methyl cation. The activity of fractions against pathogenic microbes has been studied. The results allow the supposition that the INA-5812 antibiotic complex is a glyco- or lipoglycopeptide antibiotic of a new type, which is very promising for further study.

Convenient preparation of fluorogenic hairpin DNA probes (molecular beacons) carrying a pair of FAM fluorophores (located close to 5'-terminus of the probe) or a pair of BHQ1 quenchers on 3'-terminus (with (BHQ1)2 or BHQ1-BHQ1 composition) is reported. These probes were used for the first time in a real-time PCR assay and showed considerable improvements in fluorogenic properties (the total fluorescence increase or signal-to-background ratio) in assay conditions vs. conventional one-FAM-one-BHQ1 molecular beacon probes as well as vs. hydrolyzable one-FAM-one-BHQ1 TaqMan probes. At the same time, such multiple modifications of the probe do not influence its Cq (a fractional PCR cycle used for quantification). The probe MB14 containing a BHQ1-BHQ1 pair showed a PCR fluorescence/background value of 9.6 which is more than two times higher than that of a regular probe MB2 (4.6). This study demonstrates prospects for the design of highly fluorogenic molecular beacon probes suitable for quantitative real-time PCR and for other potential applications (e.g. intracellular RNA detection and SNP/mutation analysis).