Immunological and mass spectrometry-based approaches to determine thresholds of the mutagenic DNA adduct O-methylguanine in vivo.

N-nitroso compounds are alkylating agents, which are widespread in our diet and the environment. They induce DNA alkylation adducts such as O-methylguanine (O-MeG), which is repaired by O-methylguanine-DNA methyltransferase (MGMT). Persistent O-MeG lesions have detrimental biological consequences like mutagenicity and cytotoxicity.

MyD88-dependent pro-interleukin-1β induction in dendritic cells exposed to food-grade synthetic amorphous silica.

Background: Dendritic cells (DCs) are specialized first-line sensors of foreign materials invading the organism. These sentinel cells rely on pattern recognition receptors such as Nod-like or Toll-like receptors (TLRs) to launch immune reactions against pathogens, but also to mediate tolerance to self-antigens and, in the intestinal milieu, to nutrients and commensals. Since inappropriate DC activation contributes to inflammatory diseases and immunopathologies, a key question in the evaluation of orally ingested nanomaterials is whether their contact with DCs in the intestinal mucosa disrupts this delicate homeostatic balance between pathogen defense and tolerance.

Iron phosphate nanoparticles for food fortification: Biological effects in rats and human cell lines.

Nanotechnology offers new opportunities for providing health benefits in foods. Food fortification with iron phosphate nanoparticles (FePO NPs) is a promising new approach to reducing iron deficiency because FePO NPs combine high bioavailability with superior sensory performance in difficult to fortify foods. However, their safety remains largely untested.

In-Gene Quantification of O(6)-Methylguanine with Elongated Nucleoside Analogues on Gold Nanoprobes.

Exposure of DNA to chemicals can result in the formation of DNA adducts, a molecular initiating event in genotoxin-induced carcinogenesis. O(6)-Methylguanine (O(6)-MeG) is a highly mutagenic DNA adduct that forms in human genomic DNA upon reaction with methylating agents of dietary, environmental, or endogenous origin. In this work, we report the design and synthesis of novel non-natural nucleoside analogues 1'-β-[1-naphtho[2,3-d]imidazol-2(3H)-one)]-2'-deoxy-d-ribofuranose and 1'-β-[1-naphtho[2,3-d]imidazole]-2'-deoxy-d-ribofuranose and their use for quantifying O(6)-MeG within mutational hotspots of the human KRAS gene.

Gold nanoprobes for detecting DNA adducts.

A colorimetric probe for the detection of a mutagenic DNA adduct within a sequence was created. The probe involves incorporation of a synthetic nucleoside that selectively pairs opposite a target DNA adduct into oligonucleotides conjugated to gold nanoparticles (AuNPs).

Reversible aggregation of DNA-decorated gold nanoparticles controlled by molecular recognition.

The programmable assembly of functional nanomaterials has been extensively addressed; however, their selective reversible assembly in response to an external stimulus has been more difficult to realize. The specificity and programmable interactions of DNA have been exploited for the rational self-assembly of DNA-conjugated nanoparticles, and here we demonstrate the sequence-controlled disaggregation of DNA-modified gold nanoparticles simply by employing two complementary oligonucleotides. Target oligonucleotides with perfectly matching sequence enabled dissociation of aggregated nanoparticles, whereas oligonucleotides differing by one nucleotide did not cause disassembly of the aggregated nanoparticles.

Dipstick test for DNA-based food authentication. Application to coffee authenticity assessment.

This paper reports DNA-based food authenticity assays, in which species identification is accomplished by the naked eye without the need of specialized instruments. Strongly colored nanoparticles (gold nanoparticles) are employed as reporters that enable visual detection. Furthermore, detection is performed in a low-cost, disposable, dipstick-type device that incorporates the required reagents in dry form, thereby avoiding multiple pipetting and incubation steps.

Quantitative bioluminometric method for DNA-based species/varietal identification in food authenticity assessment.

A method is reported for species quantification by exploiting single-nucleotide polymorphisms (SNPs). These single-base changes in DNA are particularly useful because they enable discrimination of closely related species and/or varieties. As a model, quantitative authentication studies were performed on coffee.

Screening for unknown mutations by a bioluminescent protein truncation test with homogeneous detection.

The protein truncation test (PTT) is important in screening for unknown mutations that cause premature termination of mRNA translation. PTT involves amplification of the interrogated sequence, in vitro transcription/translation, separation of the generated polypeptides, and detection. In this article, we report a bioluminescent protein truncation test, in which the detection of the nascent protein is performed directly in the expression mixture, within seconds, without the need for separation and purification.