(±)-Pheharmines A-B, two pairs of racemic alkaloids with a morpholino[4,3,2-hi]ß-carboline core, from the roots of Peganum harmala.

Two pairs of unprecedented ß-carboline-phenylpropanoid heterogeneous alkaloids, (±)-pheharmines A-B (1-4), characterized by a morpholino[4,3,2-hi]ß-carboline core with two chiral centers, were isolated from the roots of Peganum harmala. The structures, including their absolute configurations, were identified using spectroscopic analyses and electronic circular dichroism (ECD) calculations. The biosynthetic hypothesis for the formation of pheharmines A-B was proposed. Compounds 1-4 exhibited moderate cytotoxic activities against HL-60 cell lines.

Preparation of Monoclonal Antibody and Development of Indirect Competitive Enzyme-Linked Immunosorbent Assay and Fluorescence-Linked Immunosorbent Assay for Detecting 3-Amino-5-methylmorpholino-2-oxazolidinone (AMOZ) in Edible Animal Tissue.

To monitor the illegal used of furaltadone, a highly sensitive indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and fluorescence-linked immunosorbent assay (FLISA) based on a monoclonal antibody (mAb) were developed for the detection of 3-amino-5-methylmorpholino-2-oxazolidinone (AMOZ), the major metabolite of furaltadone in animal tissues. The highly specific mAb, which was very sensitive to a nitrophenyl derivative of AMOZ (2-NP-AMOZ) with IC50 values of 0.11 and 0.09 ng/mL for ic-ELISA and FLISA, respectively, was selected for the development of immunoassays. For both the ic-ELISA and FLISA for AMOZ-spiked experiments, acceptable recovery rates of 81.1-105.3% and coefficients of variation of 4.7-9.8% were obtained. In addition, results from both ic-ELISA and FLISA methods for spiked samples' data showed excellent correlation coefficients ranging from 0.9652 to 0.9927. Meanwhile, the proposed ic-ELISA and FLISA for thirty spiked samples were confirmed by standard LC-MS/MS with high correlation coefficients of 0.9911 and 0.9921, respectively. These results suggest that the developed ic-ELISA and FLISA are valid and cost-effective tools for high-throughput monitoring methods for AMOZ residues in animal tissues.

Detection of unique Ebola virus oligonucleotides using fluorescently-labeled phosphorodiamidate morpholino oligonucleotide probe pairs.

Here we identify a low-cost diagnostic platform using fluorescently-labeled phosphorodiamidate morpholino oligonucleotide (PMO) probe pairs, which upon binding target oligonucleotides undergo fluorescence resonance energy transfer (FRET). Using a target oligonucleotide derived from the Ebola virus (EBOV), we have derivatized PMO probes with either Alexa Fluor488 (donor) or tetramethylrhodamine (acceptor). Upon EBOV target oligonulceotide binding, observed changes in FRET between PMO probe pairs permit a 25 pM lower limit of detection; there is no off-target binding within a complex mixture of nucleic acids and other biomolecules present in human saliva. Equivalent levels of FRET occur using PMO probe pairs for single or double stranded oligonucleotide targets. High-affinity binding is retained under low-ionic strength conditions that disrupt oligonucleotide secondary structures (e.g., stem-loop structures), ensuring reliable target detection. Under these low-ionic strength conditions, rates of PMO probe binding to target oligonucleotides are increased 3-fold relative to conventional high-ionic strength conditions used for nucleic acid hybridization, with half-maximal binding occurring within 10 min. Our results indicate an ability to use PMO probe pairs to detect clinically relevant levels of EBOV and other oligonucleotide targets in complex biological samples without the need for nucleic acid amplification, and open the possibility of population screening that includes assays for the genomic integration of DNA based copies of viral RNA.

Surface Plasmon Resonance-Based Concentration Determination Assay: Label-Free and Antibody-Free Quantification of Morpholinos.

Surface plasmon resonance (SPR) is a physical process that allows label-free and real-time detection of biomolecular interactions. SPR provides a rapid and quantitative method for studying interactions of macromolecules such as proteins and nucleic acids. Antisense Morpholino oligomers are widely used to regulate gene expression and the US FDA has approved a Morpholino drug for treatment of Duchenne muscular dystrophy. Here, we describe an antibody-free, label-free, high-throughput, and walk-away SPR method for quantification of Morpholino compounds extracted from biological specimens. This provides a valuable way for determining pharmacokinetics and pharmacodynamics of Morpholino oligomers in biological matrices for research and therapeutic applications.

Structural elucidation of foldamers with no long range conformational order.

The synthesis and structural investigation of aromatic-aliphatic oligoamide foldamers reveals a zig-zag tape conformation with local conformational variability that precludes long range order.

Monoclonal antibody-based fluorescence polarization immunoassay for high throughput screening of furaltadone and its metabolite AMOZ in animal feeds and tissues.

A simple and fast homogeneous fluorescent polarization immunoassay (FPIA) was developed for the determination of furaltadone and its metabolite 3-amino-5-methylmorpholino-2-oxazolidinone (AMOZ). Monoclonal antibody with high cross-reactivity to furaltadone and the nitrophenyl derivative of AMOZ (NPAMOZ) were produced against a novel immunogen and the effects of several synthesized tracers on FPIA sensitivity studied. The proposed FPIA, using an optimum antibody and tracer pair, had an IC50 of 4.3 µg L⁻¹ and limit of detection at 0.6 µg L⁻¹ for furaltadone, and 2.7 µgL⁻¹ and 0.3 µg L⁻¹ for NPAMOZ. Recoveries of furaltadone from animal feeds by FPIA ranged from 79.6 to 87.7%, while recoveries of AMOZ from animal tissues ranged from 72.9 to 83.1%. Good correlation (R>0.99) between the results of this FPIA and a standard analytical method was obtained. The FPIA does not require separation or washing steps and the total time required for equilibrium of the antibody-tracer interaction is only 10 min. These results indicated that the proposed FPIA offers great potential and utility for the high throughput screening of furaltadone residues in animal feed and its metabolite AMOZ residues in animal tissues.