Search results for "MOLECULE"

Overcoming of P-glycoprotein-mediated multidrug resistance of tumors in vivo by drug combinations

2014

Summary Inhibition of P-glycoprotein represents an attractive possibility to modulate resistance of cancer cells to anticancer drugs. One major strategy to overcome P-glycoprotein-mediated multidrug resistance (MDR) of tumors is to increase intracellular concentrations of anticancer drugs. This can be achieved by blocking of P-glycoprotein-mediated drug efflux using synthetic or natural small molecules or monoclonal antibodies, which bind to various parts of the efflux channel. Another possibility to increase intracellular drug concentrations can be reached by nanoparticles. A further major strategy to overcome MDR involves the downregulation of P-glycoprotein expression either by therapeut…

Self-assembly of monodisperse oligonucleotide-elastin block copolymers into stars and compound micelles.

2010

The Origin of Metazoan Complexity: Porifera as Integrated Animals

2011

SYNOPSIS. Sponges [Porifera] are the phylogenetically oldest metazoan phylum still extant today; they share the closest relationship with the hypothetical common metazoan ancestor, the Urmetazoa. During the past 8 years cDNAs coding for proteins involved in cell-cell- and cell-tissue interaction have been cloned from sponges, primarily from Suberites domuncula and Geodia cydonium and their functions have been studied in vivo as well as in vitro. Also, characteristic elements of the extracellular matrix have been identified and cloned. Those data confirmed that all metazoan phyla originate from one ancestor, the Urmetazoa. The existence of cell adhesion molecules allowed the emergence of a c…

Connection between Absorption Properties and Conformational Changes in Deinococcus radiodurans Phytochrome

2014

Phytochromes consist of several protein domains and a linear tetrapyrrole molecule, which interact as a red-light-sensing system. In this study, size-exclusion chromatography and light-scattering techniques are combined with UV-vis spectroscopy to investigate light-induced changes in dimeric Deinococcus radiodurans bacterial phytochrome (DrBphP) and its subdomains. The photosensory unit (DrCBD-PHY) shows an unusually stable Pfr state with minimal dark reversion, whereas the histidine kinase (HK) domain facilitates dark reversion to the resting state. Size-exclusion chromatography reveals that all phytochrome fragments remain as dimers in the illuminated state and dark state. Still, the elut…

Tetra-urea calix[4]arenes 1,3-bridged at the narrow rim.

2009

The synthesis of special tetra-urea calix[4]arene derivatives is described. Two propyl ether groups in 1,3-position and a 5-iodo-isophthalamide bridge connecting two aminopropylether residues in 2,4-position at the narrow rim keep the molecule fixed in the cone conformation. The aryl urea residues are substituted by decyloxy groups in p-position to increase the solubility in apolar solvents, while the iodo substituent allows further functionalization. Two single crystal X-ray structures of 3 and 4 show a strongly pinched cone conformation in which the bridged phenol units are bent outwards, while the phenol units bearing the propyl ether groups are nearly parallel. The molecules are flexibl…

The C-12 and C-20 configurations of some neo-clerodane diterpenoids isolated from Teucrium species

1986

Abstract A convenient and conclusive method for determining the C-12 stereochemistry of neo-clerodan-20,12-olide derivatives, even when only one epimer is available, is by 1H NMR NOE measurements. The C-12 configuration of 26 neo-clerodane diterpenoids isolated from Teucrium species has been re-examined by using this type of experiment. The results indicated that all the previous assignments were correct, except for teupyreinin, where the previously assigned C-12(S) configuration must be amended to C-12(R). This was confirmed by chemical transformations and additional 1H and 13C NMR studies. Furthermore, the NOE experiments allowed the assignment of a C-20(S) configuration for teuflavin, th…

Virulent and nonvirulent Flavobacterium columnare colony morphologies: characterization of chondroitin AC lyase activity and adhesion to polystyrene

2011

Aims:  Colony morphology variants of fish pathogenic Flavobacterium columnare were studied to clarify the role of colony morphology change in the virulence of the bacterium. Typical rhizoid colony (Rz) variants are virulent and moderately adherent, nonrhizoid rough (R) colony variants are nonvirulent and highly adherent, and soft colony (S) variants are nonvirulent and poorly adherent. Methods and Results:  Chondroitin AC lyase activity, adhesion to polystyrene at different temperatures and after modification of bacterial surface, and lipopolysaccharide (LPS) profiles of the variants were studied. The chondroitinase activity was significantly higher in the virulent, rhizoid variants than in…

Novel structural insights into F-actin-binding and novel functions of calponin homology domains.

2008

Tandem calponin homology (CH) domains are well-known actin filaments (F-actin) binding motifs. There has been a continuous debate about the details of CH domain-actin interaction, mainly because atomic level structures of F-actin are not available. A recent electron microscopy study has considerably advanced our structural understanding of CH domain:F-actin complex. On the contrary, it has recently also been shown that CH domains can bind other macromolecular systems: two CH domains from separate polypeptides Ncd80, Nuf2 can form a microtubule-binding site, as well as tandem CH domains in the EB1 dimer, while the single C-terminal CH domain of alpha-parvin has been observed to bind to a alp…

Mildronate as a Regulator of Protein Expression in a Rat Model of Parkinson’s Disease

2011

Background. Mildronate (3-[2,2,2-trimethylhydrazinium] propionate dihydrate) traditionally is a well-known cardioprotective drug. However, our recent studies convincingly demonstrated its neuroprotective properties. The aim of the present study was to evaluate the influence of mildronate on the expression of proteins that are involved in the differentiation and survival of the nigrostriatal dopaminergic neurons in the rat model of Parkinson’s disease (PD). The following biomarkers were used: heat shock protein 70 (Hsp70, a molecular chaperone), glial cell line-derived nerve growth factor (GDNF, a growth factor promoting neuronal differentiation, regeneration, and survival), and neural cell …

Study of [2-(2’-pyridyl)imidazole] complexes to confirm two main characteristic thermoanalytical behaviors of transition metal complexes based on imi…

2016

Abstract Imidazole derivative ligands are recognized as useful models for biomimetic complexes. Among the inorganic–organic hybrid complexes, those with derivatives of imidazole heterocyclic N-donor ligands are interesting for their framework. In previous studies of complexes with imidazole derivative ligands, our group reported two main thermally induced decomposition behaviors supporting two different systematic decomposition trends. In this work, one of these characteristic decomposition mechanisms was again found. The final goal of these serial studies is the possibility to provide, by the experimental evidences, a prediction model of thermal stability and decomposition typical behavior…