Search results for "Polycyclic compound"
showing 10 items of 391 documents
A closer look at the cholesterol sensor
2002
Abstract Transport of the sterol regulatory element-binding protein (SREBP) cleavage-activating protein (SCAP)–SREBP complex from the endoplasmic reticulum (ER) to the Golgi is the central event mediating the cholesterol-feedback process in mammalian cells. A conformational change in SCAP is a crucial step; when cholesterol levels are high, the conformation of SCAP enables the SCAP–SREBP complex to associate with an insulin-induced gene (INSIG) retention protein in the ER. By contrast, when cholesterol levels are low, SCAP switches to a conformation that enables the dissociation of the retention protein and the association of SCAP–SREBP with COP II vesicles.
Male breast cancer.
2010
Male breast cancer (MaleBC) is a rare disease, accounting for <1% of all male tumors. During the last few years, there has been an increase in the incidence of this disease, along with the increase in female breast cancer (FBC). Little is known about the etiology of MaleBC: hormonal, environmental and genetic factors have been reported to be involved in its pathogenesis. Major risk factors include clinical disorders carrying hormonal imbalances, radiation exposure and, in particular, a positive family history (FH) for BC, the latter suggestive of genetic susceptibility. Rare mutations in high-penetrance genes (BRCA1 and BRCA2) confer a high risk of BC development; low-penetrance gene mutati…
13C NMR study of some polychloro-isobutane and -isobutene compounds
1984
The 13C chemical shifts and the carbon–proton coupling constants have been determined for some chlorinated isobutane and isobutene compounds. The one-bond coupling constants in isobutane derivatives showed a regular increase with an increasing number of γ-chlorine substituents. The three-bond coupling constant of the methyl carbon decreased from 4.2 to 2.0 Hz as the number of chlorine substituents in the γ-position increased. In the isobutene compounds, the vicinal coupling of C-1 was larger to protons in a group that is trans with respect to a chlorine substituent on C-1 than to those in the corresponding group cis to the chlorine. The vicinal coupling constants between atoms in geminal gr…
The Biosynthesis of Rare Homo-Amino Acid Containing Variants of Microcystin by a Benthic Cyanobacterium
2019
Microcystins are a family of chemically diverse hepatotoxins produced by distantly related cyanobacteria and are potent inhibitors of eukaryotic protein phosphatases 1 and 2A. Here we provide evidence for the biosynthesis of rare variants of microcystin that contain a selection of homo-amino acids by the benthic cyanobacterium Phormidium sp. LP904c. This strain produces at least 16 microcystin chemical variants many of which contain homophenylalanine or homotyrosine. We retrieved the complete 54.2 kb microcystin (mcy) gene cluster from a draft genome assembly. Analysis of the substrate specificity of McyB1 and McyC adenylation domain binding pockets revealed divergent substrate specificity …
Lovastatin causes sensitization of HeLa cells to ionizing radiation‐induced apoptosis by the abrogation of G2 blockage
2003
To investigate the effect of inhibition of Ras/Rho-regulated signalling by 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) on radiation-induced cell killing and apoptosis.Different human cell lines were pretreated or not with lovastatin before exposure to gamma-rays. Afterwards, radiation-induced cell killing, formation and repair of double-strand breaks, activation of radiation-inducible signal mechanisms (i.e. p53, p21, extracellular-signal-related kinase (ERK), NF-kappaB), changes in cell cycle progression and apoptosis were analysed.As shown by a colony formation assay, lovastatin sensitized HeLa cells to gamma-radiation-induced cell killing. The lovastati…
d-Alanyl-d-Alanine Carboxypeptidase in the Bacterial Form and L-Form of Proteus mirabilis
1975
Membranes of the bacterial form and the stable and unstable L-forms of Proteus mirabilis contain LD and DD-carboxypeptidase. The DD-carboxypeptidase is inhibited non-competitively by penicillin G. The enzyme of the bacterial form is highly penicillin-sensitive (Ki - 4 X 10(-9) M penicillin G). Inhibition is only partly reversible by treatment with penicillinase or by dialysis against buffer. In contrast, the DD-carboxypeptidase of the unstable L-form, grown in the presence of penicillin, is 175-fold less penicillin-sensitive (Ki = 7 X 10(7) M penicillin G). Inhibition is completely reversed by penicillinase or dialysis. After inhibition by penicillin and subsequent reactivation the penicill…
Lovastatin protects human endothelial cells from the genotoxic and cytotoxic effects of the anticancer drugs doxorubicin and etoposide
2006
Background and purpose: 3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) are frequently used lipid-lowering drugs. Moreover, they exert pleiotropic effects on cellular stress responses and death. Here, we analysed whether lovastatin affects the sensitivity of primary human endothelial cells (HUVEC) to the anticancer drug doxorubicin. Experimental approach: We investigated whether pretreatment of HUVEC with low dose of lovastatin influences the cellular sensitivity to doxorubicin. To this end, cell viability, proliferation and apoptosis as well as DNA damage-triggered stress response were analysed. Key results: Lovastatin reduced the cytotoxic potency of doxorub…
Evaluation of the DNA microarray “AMR Direct Flow Chip Kit” for detection of antimicrobial resistance genes from Gram-positive and Gram-negative bact…
2019
Abstract Introduction The AMR Direct Flow Chip assay allows the simultaneous detection of a large variety of antibiotic resistance genetic markers. To assess this kit's performance, we use isolated colonies as starting material. The assay has been approved by the European Economic Area as a suitable device for in vitro diagnosis (CE IVD) using clinical specimens. Methods A total of 210 bacterial isolates harbouring either one or more antimicrobial resistance genes including plasmid-encoded extended-spectrum β-lactamases (SHV, CTX-M) and carbapenemases (GES, SME, KPC, NMC/IMI, SIM, GIM, SPM, NDM, VIM, IMP, and OXA), mecA, vanA and vanB, and 30 controls were included. Results The assay displa…
A novel VIM‐type metallo‐beta‐lactamase (VIM‐14) in a Pseudomonas aeruginosa clinical isolate from a neonatal intensive care unit
2011
AbstractA Pseudomonas aeruginosa highly resistant to carbapenems was isolated in a neonatal intensive care unit in Palermo, Italy. The strain was found to carry a novel VIM‐type enzyme, classified as VIM‐14. The novel enzyme differs from VIM‐4 in a G31S mutation. VIM‐14 was harboured in a class 1 integron with a new organization. The integron carried the genes aac7, blaVIM‐14, blaOXA‐20 and aac4 in that order.
Partitioning study of polycyclic aromatic hydrocarbons between water and some selected water-insoluble phases
2007
An investigation on the partitioning of naphthalene and phenanthrene between water and some water-insoluble phases has been carried out by Uv-vis-NIR spectrophotometry. The analysis of the experimental results emphasized the role of intermolecular interactions and structural features of the hosting phases as driving forces of the partitioning of these polycyclic aromatic hydrocarbons. The critical comparison of the resulting distribution constants allowed to evaluate the potentials of some extracting phases to set up sensitive analytical methods and/or effective environment remediation technologies.