Роль органічних речовин води Нафтуся у її фізіологічній активності

В экспериментах на крысах, а также ex vivo, используя воду Нафтуся из различных скважин и в разные периоды ее мониторинга, а также выделенные из Нафтуси ее гидрофобные и гидрофильные органические вещества, выявлено 5 различающихся между собой кластеров физиологических эффектов, обусловленных количественными и качественными различиями органической компоненты Нафтуси.In experiments on rats, and also ex vivo, using water Naftussya from various chinks and in the different periods of her monitoring, and also allocated from Naftussya her hydrophobic and hydrophyle organic substances, is revealed 5 differing among themselves clusters of physiological effects caused by quantitative and qualitative distinctions organic components Naftussya

A KDM4A-PAF1-mediated epigenomic network is essential for acute myeloid leukemia cell self-renewal and survival

Epigenomic dysregulation is a common pathological feature in human hematological malignancies. H3K9me3 emerges as an important epigenomic marker in acute myeloid leukemia (AML). Its associated methyltransferases, such as SETDB1, suppress AML leukemogenesis, whilst H3K9me3 demethylases KDM4C is required for mixed-lineage leukemia rearranged AML. However, the specific role and molecular mechanism of action of another member of the KDM4 family, KDM4A has not previously been clearly defined. In this study, we delineated and functionally validated the epigenomic network regulated by KDM4A. We show that selective loss of KDM4A is sufficient to induce apoptosis in a broad spectrum of human AML cells. This detrimental phenotype results from a global accumulation of H3K9me3 and H3K27me3 at KDM4A targeted genomic loci thereby causing downregulation of a KDM4A-PAF1 controlled transcriptional program essential for leukemogenesis, distinct from that of KDM4C. From this regulatory network, we further extracted a KDM4A-9 gene signature enriched with leukemia stem cell activity; the KDM4A-9 score alone or in combination with the known LSC17 score, effectively stratifies high-risk AML patients. Together, these results establish the essential and unique role of KDM4A for AML self-renewal and survival, supporting further investigation of KDM4A and its targets as a potential therapeutic vulnerability in AML

A new perspective on fungal metabolites:Identification of bioactive compounds from fungi using zebrafish embryogenesis as read-out

There is a constant need for new therapeutic compounds. Fungi have proven to be an excellent, but underexplored source for biologically active compounds with therapeutic potential. Here, we combine mycology, embryology and chemistry by testing secondary metabolites from more than 10,000 species of fungi for biological activity using developing zebrafish (Danio rerio) embryos. Zebrafish development is an excellent model for high-throughput screening. Development is rapid, multiple cell types are assessed simultaneously and embryos are available in high numbers. We found that 1,526 fungal strains produced secondary metabolites with biological activity in the zebrafish bioassay. The active compounds from 39 selected fungi were purified by liquid-liquid extraction and preparative HPLC. 34 compounds were identified by a combination of chemical analyses, including LCMS, UV-Vis spectroscopy/ spectrophotometry, high resolution mass spectrometry and NMR. Our results demonstrate that fungi express a wide variety of biologically active compounds, consisting of both known therapeutic compounds as well as relatively unexplored compounds. Understanding their biological activity in zebrafish may provide insight into underlying biological processes as well as mode of action. Together, this information may provide the first step towards lead compound development for therapeutic drug development

The role of the disulfide bond in the interaction of islet amyloid polypeptide with membranes

Human islet amyloid polypeptide (hIAPP) forms amyloid fibrils in pancreatic islets of patients with type 2 diabetes mellitus. It has been suggested that the N-terminal part, which contains a conserved intramolecular disulfide bond between residues 2 and 7, interacts with membranes, ultimately leading to membrane damage and β-cell death. Here, we used variants of the hIAPP1–19 fragment and model membranes of phosphatidylcholine and phosphatidylserine (7:3, molar ratio) to examine the role of this disulfide in membrane interactions. We found that the disulfide bond has a minor effect on membrane insertion properties and peptide conformational behavior, as studied by monolayer techniques, 2H NMR, ThT-fluorescence, membrane leakage, and CD spectroscopy. The results suggest that the disulfide bond does not play a significant role in hIAPP–membrane interactions. Hence, the fact that this bond is conserved is most likely related exclusively to the biological activity of IAPP as a hormone

Structure of glycosylated and unglycosylated gag and gag-pol precursor proteins of Moloney murine leukemia virus.

Precursor polyproteins containing translational products of the gag gene of Moloney murine leukemia virus were purified by gel electrophoresis and cleaved into large fragments by hydroxylamine, mild acid hydrolysis, or cyanogen bromide. The hydroxylamine cleavage method (specific for asparagine-glycine bonds) was adapted especially for this study. The electrophoretic mobility and antigenicity of the fragments and, in some cases, the presence or absence of [35S]methionine revealed detailed information on the structure of Pr65gag, gPr80gag, and Pr75gag (the unglycosylated variant of gPr80gag formed in vivo in the presence of tunicamycin or in vitro in a reticulocyte cell-free system). When compared with Pr65gag, gPr80gag contains 7,000 daltons of additional amino acids, presumably as, or as part of, a leader sequence at or very close to its N terminus. We present evidence that this leader may have replaced part of the p15 sequence. Furthermore, gPr80gag contains three separate carbohydrate groups. One is attached to the presumed leader sequence or to the p15 domain, and two are attached to the p30 domain. Each of the Moloney murine leukemia virus gag precursor proteins Pr65gag, gPr80gag, and Pr75gag corresponds with a read-through product into the pol gene. We designated these products Pr180gag-pol, gPr200gag-pol, and Pr190gag-pol (the unglycosylated variant of gPr200gag-pol), respectively. gPr200gag-pol contains all of the extra amino acids and carbohydrate groups present in gPr80gag and at least one carbohydrate group in its pol sequences

Adhesion inhibition of F1C-fimbriated escherichia coli and pseudomonas aeruginosa PAK and PAO by multivalent carbohydrate ligands

In order to evaluate their inhibition of bacterial adhesion, the carbohydrate sequences GalNAcβ1→4Gal and GalNAcβ1→4Galβ1→4Glc were synthesized. The disaccharide was conjugated to dendrons based on the 3,5-di-(2-aminoethoxy)-benzoic acid branching unit to yield di- and tetravalent versions of these compounds. A divalent compound was also prepared that had significantly longer spacer arms. Relevant monovalent compounds were prepared for comparison. Their anti-adhesion properties against F1C-fimbriated uropathogenic Escherichia coli were evaluated in an ELISA-type assay by using a recombinant strain and also by using Pseudomonas aeruginosa strains PAO and PAK. Adhesion inhibition was observed in all cases, and multivalency effects of up to one order of magnitude were observed. The combination of spacer and multivalency effects led to a 38-fold increase in the potency of a divalent inhibitor with long spacer arms towards the PAO strain when compared with the free carbohydrate

The alphaM1 transmembrane segment of the nicotinic acetylcholine receptor interacts strongly with model membranes

The transmembrane domain of the nicotinic acetylcholine receptor (nAChR) plays a role in the regulation of the activity of this important ligand-gated ion channel. The lipid composition of the host membrane affects conformational equilibria of the nAChR and several classes of inhibitors, most notably anaesthetics, interact directly or indirectly with the four transmembrane M-segments, M1-M4, of the nAChR subunits. It has proven difficult to gain insight into structure-function relationships of the M-segments in the context of the entire receptor and the biomembrane environment. However, model membrane systems are well suited to obtain detailed information about protein-lipid interactions. In this solid-state NMR study, we characterized interactions between a synthetic M1 segment of the T. californica nAChR and model membranes of different phosphatidylcholine (PC) lipids. The results indicate that M1 interacts strongly with PC bilayers: the peptide orders the lipid acyl chains and induces the formation of small vesicles, possibly through modification of the lateral pressure profile in the bilayer. The multilamellar vesicle morphology was stabilized by the presence of cholesterol, implying that either the rigidity or the bilayer thickness is a relevant parameter for M1-membrane interactions, which also has been suggested for the entire nAChR. Our results suggest that the model systems are to a certain extent sensitive to peptide-bilayer hydrophobic matching requirements, but that the lipid response to hydrophobic mismatch alone is not the explanation. The effect of M1 on different PC bilayers may indicate that the peptide is conformationally flexible, which in turn would support a membrane-mediated modulation of the conformation of transmembrane segments of the nAChR. <br/

The alphaM1 segment of the nicotinic acetylcholine receptor exhibits conformational flexibility in a membrance environment

The transmembrane domain of the nicotinic acetylcholine receptor (nAChR) is predominantly ?-helical, and of the four distinctly different transmembrane M-segments, only the helicity of M1 is ambiguous. In this study, we have investigated the conformation of a membrane-embedded synthetic M1 segment by solid-state nuclear magnetic resonance (NMR) methods. A 35-residue peptide representing the extended ?M1 domain 206–240 of the Torpedo californica nAChR was synthesized with specific 13C- and 15N-labelled amino acids, and was incorporated in different phosphatidylcholine model membranes. The chemical shift of the isotopic labels was resolved by magic angle spinning (MAS) NMR and could be related to the secondary structure of the ?M1 analog at the labelled sites. Our results show that the membrane-embedded ?M1 segment forms an unstable ?-helix, particularly near residue Leu18 (?Leu223 in the entire nAChR). This non-helical tendency was most pronounced when the peptide was incorporated in fully hydrated phospholipid bilayers, with an estimated 40–50% of the peptides having an extended conformation at position Leu18. We propose that the conserved proline residue at position 16 in the ?M1 analog imparts a conformational flexibility on the M1 segments that could enable membrane-mediated modulation of nAChR activity

Azide–alkyne cycloaddition affording enzymatically tunable bisubstrate based inhibitors of histone acetyltransferase PCAF

A novel strategy to prepare bisubstrate based inhibitors for histone acetyltransferases is presented. To obtain these, azido peptides derived from histone H3 incorporating either a serine or a phosphoserine residue were connected to a propargyl coenzyme A derivative through copper catalyzed click chemistry. The resulting inhibitors were tested with therapeutically relevant acetyltransferase PCAF. Increased potency of the phosphoserine containing inhibitor was observed. The synthetic strategy presented may be used for developing bisubstrate based inhibitors against any acetyltransferase

Interference with protein-protein interactions involved in protease inhibitor complex formation

No abstract available