An estrogen-platinum terpyridine conjugate: DNA and protein binding and cellular delivery

A platinum metal complex in which terpyridine joins estradiol (via an ethynyl link) to a platinum with a labile ligand (chloride) has been designed, synthesised and its X-ray crystal structure determined. The aim of this work was to link a targeting motif (in this case estrogen) to a metal-based biomolecule recognition unit (the platinum moiety). The target molecule: 17alpha-[4'-ethynyl-2,2':6',2'-terpyridine]-17beta-estradiol platinum(II) chloride (PtEEtpy) has been shown to bind to both human and bovine serum albumin (SA) and to DNA. FTICR mass spectrometry shows that the bimolecular units are in each case linked through coordination to the platinum with displacement of the chloride ligand. Circular dichroism indicates that a termolecular entity involving PtEEtpy, SA and DNA is formed. A range of electrospray mass spectrometry experiments showed that the PtEEtpy complex breaks and forms coordination bonds relatively easily. A whole cell estrogen receptor assay in an estrogen receptor positive cell (MCF-7) confirms binding of both EEtpy and PtEEtpy to the estrogen receptor in cells. The work demonstrates the concept of linking a targeting moiety (in this case estrogen) to a DNA binding agent.     

Potential inhibitors of chemokine function: Analysis of noncovalent complexes of cc chemokine and small polyanionic molecules by ESI FT-ICR mass spectrometry

Chemokines play a critical role in inducing chemotaxis, extravasation, and activation of leukocytes both in routine immunosurveillance and autoimmune diseases. Traditionally, to disrupt chemokine function, strategies have focused on blockage of its interaction with the receptor. Recently, it has been demonstrated that binding to glycosaminoglycans (GAGs) is also required for the in vivo activity of many chemokines. Thus, interference with the GAG-binding of chemokines may offer an alternative, valid, anti-inflammatory strategy. However, the potential of using small polyanions to inhibit the interactions between chemokines and cell surface GAGs has not been fully explored. In this study, a mass spectrometry based filtration trapping assay was utilized to study the interactions between two CCR 2 ligands (MCP-1/CCL2 and MCP-3/CCL7) and a series of low molecular weight, polyanionic molecules. Findings were confirmed by using a hydrophobic trapping assay. The results indicated that Arixtra (fondaparinux sodium), sucrose octasulfate, and suramin were specific binders of the chemokines, while cyclodextrin sulfate, although the most highly sulfated molecule among the ones investigated, showed no binding. The binding stoichiometry of the small molecule ligand was determined from the measured molecular weight of the noncovalent complex. Furthermore, the dissociation constant between MCP-3 and Arixtra was determined by using electrospray ionization Fourier transform ion cyclotron resonance (ESI FT-ICR) mass spectrometry, which compared favorably with the result of the isothermal titration calorimetry (ITC) assay. The relative binding affinity of these ligands to MCP-3 was also determined using a competitive filtration trapping assay.     

A monoselective sphingosine-1-phosphate receptor-1 agonist prevents allograft rejection in a stringent rat heart transplantation model

FTY720 is an immunomodulator with demonstrated efficacy in a phase II trial of relapsing multiple sclerosis. FTY720-phosphate, the active metabolite generated upon phosphorylation in vivo, acts as a potent agonist on four of the five known sphingosine-1-phosphate (S1P(1)) receptors. AUY954, an aminocarboxylate analog of FTY720, is a low nanomolar, monoselective agonist of the S1P(1) receptor. Due to its selectivity and pharmacokinetic profile, AUY954 is an excellent pharmacological probe of S1P(1)-dependent phenomena. Oral administration of AUY954 induces a profound and reversible reduction of circulating lymphocytes and, in combination with RAD001 (Certican/Everolimus, an mTOR inhibitor), is capable of prolonging the survival of cardiac allografts in a stringent rat transplantation model. This demonstrates that a selective agonist of the S1P(1) receptor is sufficient to achieve efficacy in an animal model of transplantation.     

Evaluating and Improving a Learning Trajectory for Linear Measurement in Elementary Grades 2 and 3: A Longitudinal Study

We examined children's development of strategic and conceptual knowledge for linear measurement. We conducted teaching experiments with eight students in grades 2 and 3, based on our hypothetical learning trajectory for length to check its coherence and to strengthen the domain-specific model for learning and teaching. We checked the hierarchical structure of the trajectory by generating formative instructional task loops with each student and examining the consistency between our predictions and students' ways of reasoning. We found that attending to intervals as countable units was not an adequate instructional support for progress into the Consistent Length Measurer level; rather, students must integrate spaces, hash marks, and number labels on rulers all at once. The findings have implications for teaching measure-related topics, delineating a typical developmental transition from inconsistent to consistent counting strategies for length measuring. We present the revised trajectory and recommend steps to extend and validate the trajectory.     

Designing Hardware for the Boundary Condition Round Robin Challenge

Qualification of products to their vibration and shock requirements in a laboratory setting consists of two basic steps. The first is the quantification of the product’s mechanical environment in the field. The second is the process of testing the product in the laboratory to ensure it is robust enough to survive the field environment. The latter part is the subject of the “Boundary Condition for Component Qualification” challenge problem. This paper describes the challenges in determining the appropriate boundary conditions and input stimulus required to qualify the product. This paper also describes the step sand analyses that were taken to design a set of hardware that demonstrates the issue and can be used by round robin challenge participants to investigate the problem.     

Design of low-frequency ultrasonic sensors for the analysis of the draining stage of cheese production

This work presents a new ultrasonic system with a transmission mode in the 100-200 kHz frequency range. The system, composed of ultrasonic point sources, is used to monitor the mechanical properties of cheese during the early phases of production. First, our specialized sensor system is presented, and then the results obtained with the system model are compared to the results of actual experiments using the system to monitor the evolution of the medium during draining. The results of a rheological compliance test and shock pulse ultrasonic amplitude measurements agree and correspond quite accurately to the mechanical properties of the evolving physical state of the medium. This method could be used in the future to study the effect on the final cheese quality of the process parameters that interfere with cheese grain consolidation during the draining process.     

Synthesis and characterization of Zinc Oxide nanoparticles using marine Streptomyces sp. with its investigations on anticancer and antibacterial activity

Research on Chemical Intermediates - Synthesis of zinc oxide nanoparticles (ZnONPs) by an ecological approach using Streptomyces sp. as reducing agent is reported. ZnONPs were synthesized from...     

Analogues of the 2-carboxyl-6-hydroxyoctahydroindole (CHOI) unit from diverging Pd-catalyzed allylations: Selectivity as a function of the double bond position

Pd-catalyzed allylations of cyclic bis-allylic substrates, carried out either as two separate steps or in a pseudo-domino fashion, can generate 2-carboxyl-hexahydroindoles bearing an unsaturation in different positions. Sequential homologation, and epoxidation or syn-dihydroxylation steps were investigated to access analogues of the bicyclic 2-carboxyl-6-hydroxyoctahydroindole motif of aeruginosins, a family of peptides displaying serine protease inhibitor activity.     

Reactions of difluoroenoxysilanes with glycosyl donors: synthesis of difluoro-C-glycosides and difluoro-C-disaccharides

Difluoroenoxysilanes, prepared from acylsilanes and trifluoromethyltrimethylsilane under fluoride activation, were glycosylated with some glycosyl donors (acylglycosides, glycals) to yield difluoro-C-glycosides with a difluoromethylene group in the place of the anomeric oxygen. This reaction strongly depends on the substituent in the 2-position of the glycosyl donor. Application of this methodology to a xylose-derived acylsilane led to the formation of difluoro-C-disaccharides as an isosteric O-glycosyl mimetic.