Rapid Detection of the Antibiotic Sulfamethazine in Pig Body Fluids by Paper Spray Mass Spectrometry

We report herein a practical method for nonlethal detection of the antibiotic sulfamethazine in pig body fluids via the combination of simple extraction and paper spray mass spectrometry (PS-MS). This method requires minimal sample preparation while still providing high sensitivities and accuracies in complex matrices including pig whole blood (LOD = 7.9 μg/L; recovery = 95.4–103.7%), pig serum (LOD = 11.5 μg/L; recovery = 103.2–106.2%), and synthetic urine (LOD = 11.2 μg/L; recovery = 99.1–103.2%). Given a known correlation between the level of sulfamethazine in body fluids and edible tissues, this method shows great promise as a practical and nonlethal solution for rapid testing of the drug, which can substantially aid managerial decision in the livestock industry

Fluorogenic PNA probes

Fluorogenic oligonucleotide probes that can produce a change in fluorescence signal upon binding to specific biomolecular targets, including nucleic acids as well as non-nucleic acid targets, such as proteins and small molecules, have applications in various important areas. These include diagnostics, drug development and as tools for studying biomolecular interactions in situ and in real time. The probes usually consist of a labeled oligonucleotide strand as a recognition element together with a mechanism for signal transduction that can translate the binding event into a measurable signal. While a number of strategies have been developed for the signal transduction, relatively little attention has been paid to the recognition element. Peptide nucleic acids (PNA) are DNA mimics with several favorable properties making them a potential alternative to natural nucleic acids for the development of fluorogenic probes, including their very strong and specific recognition and excellent chemical and biological stabilities in addition to their ability to bind to structured nucleic acid targets. In addition, the uncharged backbone of PNA allows for other unique designs that cannot be performed with oligonucleotides or analogues with negatively-charged backbones. This review aims to introduce the principle, showcase state-of-the-art technologies and update recent developments in the areas of fluorogenic PNA probes during the past 20 years

Pyrrolidinyl Peptide Nucleic Acid Homologues: Effect of Ring Size on Hybridization Properties

The effect of ring size of four- to six-membered cyclic β-amino acid on the hybridization properties of pyrrolidinyl peptide nucleic acid with an alternating α/β peptide backbone is reported. The cyclobutane derivatives (acbcPNA) show the highest <i>T</i>_m and excellent specificity with cDNA and RNA

Pyrrolidinyl peptide nucleic acid with α/β-peptide backbone: A conformationally constrained PNA with unusual hybridization properties

We describe herein a new conformationally constrained analog of PNA carrying an alternating α/β amino acid backbone consisting of (2′R,4′R)-nucleobase-subtituted proline and (1S,2S)-2-aminocyclopentanecarboxylic acid (acpcPNA). The acpcPNA has been synthesized and evaluated for DNA, RNA and self-pairing properties by thermal denaturation experiments. It can form antiparallel hybrids with complementary DNA with high affinity and sequence specificity. Unlike other PNA systems, the thermal stability of acpcPNA·DNA hybrid is largely independent of G+C contents, and is generally higher than that of acpcPNA·RNA hybrid with the same sequence. Thermodynamic parameters analysis suggest that the A·T base pairs in the acpcPNA·DNA hybrids are enthalpically stabilized over G·C pairs. The acpcPNA also shows a hitherto unreported behavior, namely the inability to form self-pairing hybrids. These unusual properties should make the new acpcPNA a potentially useful candidate for various applications including microarray probes and antigene agents