Early postnatal exposure to di(2-ethylhexyl) phthalate causes sex-specific disruption of gonadal development in pigs.

Di(2-ethylhexyl) phthalate (DEHP) is a chemical commonly used as a plasticizer to render polyvinyl chloride products more durable and flexible. Although exposure to DEHP has raised many health concerns due to the identification of DEHP as an endocrine disruptor, it is still used in consumer products, including polyvinyl chloride plastics, medical tubing, car interiors, and children's toys. To investigate the impact of early life exposure to DEHP on the ovary and testes, newborn piglets were orally dosed with DEHP (20 or 200 mg/kg/day) or vehicle control (tocopherol-stripped corn oil) for 21 days.

Non-fluorescent quantification of single mRNA with transient absorption microscopy.

Single molecule detection is confounded by the background signals from the biological environment, such as autofluorescence, Rayleigh scattering, or turbidity in cells and tissues. In this article, we report on the utilization of gold nanoparticles (AuNPs) as an orthogonal probe for non-fluorescence detection of single molecules with a transient absorption microscopy (TAM). The developed system and concepts were validated by quantitative evaluation of human epidermal receptor 2 (Her2) mRNA in cancer cells and tissues at single copy sensitivity.

Point-of-care test for cervical cancer in LMICs.

Cervical cancer screening using Papanicolaou's smear test has been highly effective in reducing death from this disease. However, this test is unaffordable in low- and middle-income countries, and its complexity has limited wide-scale uptake. Alternative tests, such as visual inspection with acetic acid or Lugol's iodine and human papillomavirus DNA, are sub-optimal in terms of specificity and sensitivity, thus sensitive and affordable tests with high specificity for on-site reporting are needed.

Rapid and unbiased extraction of chromatin associated RNAs from purified native chromatin.

An ultra fast and unbiased method that uses salicylic acid coated magnetic nanoparticles (SAMNPs) and magnetophoretic chromatography is developed to extract chromatin associated RNAs (CARs). The SAMNPs were first used for enriching cells from the cell culture media and further used for capturing chromatin after cells were lysed. The formed SAMNPs-chromatin complexes were transferred to a viscous polyethylene glycol (PEG) solution stored in a 200-μl pipette tip.

Kinase phosphorylation monitoring with i-motif DNA cross-linked SERS probes.

We propose an ultrasensitive SERS-based peptide biosensor platform to monitor phosphorylation catalyzed by kinase in a dynamic format. The developed SERS strategy has a short response time with potential to monitor phosphorylation in live cells.

Single-cell screening and quantification of transcripts in cancer tissues by second-harmonic generation microscopy.

Fluorescence-based single molecule techniques to interrogate gene expression in tissues present a very low signal-to-noise ratio due to the strong autofluorescence and other background signals from tissue sections. This report presents a background-free method using second-harmonic generation (SHG) nanocrystals as probes to quantify the messenger RNA (mRNA) of human epidermal growth receptor 2 (Her2) at single molecule resolution in specific phenotypes at single-cell resolution directly in tissues. Coherent SHG emission from individual barium titanium oxide (BTO) nanoprobes was demonstrated, allowing for a stable signal beyond the autofluorescence window.

Trichloroethylene sensing in water based on SERS with multifunctional Au/TiO2 core-shell nanocomposites.

Herein we report on a rapid and highly sensitive scheme to detect trichloroethylene (TCE), an environmental contaminant, by surface enhanced Raman scattering (SERS) with multifunctional Au/TiO2 core-shell nanocomposites as SERS substrates. A facile approach to fabricate TiO2 shell around gold core nanocomposites is proposed as sensors for TCE detection by SERS. During detection, TCE was first oxidized due to the photocatalytic activity of the TiO2 shell and the increase in SERS intensity due to the product of TCE photooxidation can be used to determine the concentration of TCE.

Nanoscale histone localization in live cells reveals reduced chromatin mobility in response to DNA damage.

Nuclear functions including gene expression, DNA replication and genome maintenance intimately rely on dynamic changes in chromatin organization. The movements of chromatin fibers might play important roles in the regulation of these fundamental processes, yet the mechanisms controlling chromatin mobility are poorly understood owing to methodological limitations for the assessment of chromatin movements. Here, we present a facile and quantitative technique that relies on photoactivation of GFP-tagged histones and paired-particle tracking to measure chromatin mobility in live cells.

Epitaxial superlattices with titanium nitride as a plasmonic component for optical hyperbolic metamaterials.

Titanium nitride (TiN) is a plasmonic material having optical properties resembling gold. Unlike gold, however, TiN is complementary metal oxide semiconductor-compatible, mechanically strong, and thermally stable at higher temperatures. Additionally, TiN exhibits low-index surfaces with surface energies that are lower than those of the noble metals which facilitates the growth of smooth, ultrathin crystalline films.

NuMA promotes homologous recombination repair by regulating the accumulation of the ISWI ATPase SNF2h at DNA breaks.

Chromatin remodeling factors play an active role in the DNA damage response by shaping chromatin to facilitate the repair process. The spatiotemporal regulation of these factors is key to their function, yet poorly understood. We report that the structural nuclear protein NuMA accumulates at sites of DNA damage in a poly[ADP-ribose]ylation-dependent manner and functionally interacts with the ISWI ATPase SNF2h/SMARCA5, a chromatin remodeler that facilitates DNA repair.

Single-molecule tools elucidate H2A.Z nucleosome composition.

Although distinct epigenetic marks correlate with different chromatin states, how they are integrated within single nucleosomes to generate combinatorial signals remains largely unknown. We report the successful implementation of single molecule tools constituting fluorescence correlation spectroscopy (FCS), pulse interleave excitation-based Förster resonance energy transfer (PIE-FRET) and fluorescence lifetime imaging-based FRET (FLIM-FRET) to elucidate the composition of single nucleosomes containing histone variant H2A.Z (Htz1p in yeast) in vitro and in vivo.

Proliferating cell nuclear antigen (PCNA) is required for cell cycle-regulated silent chromatin on replicated and nonreplicated genes.

In Saccharomyces cerevisiae, silent chromatin is formed at HMR upon the passage through S phase, yet neither the initiation of DNA replication at silencers nor the passage of a replication fork through HMR is required for silencing. Paradoxically, mutations in the DNA replication processivity factor, POL30, disrupt silencing despite this lack of requirement for DNA replication in the establishment of silencing. We tested whether pol30 mutants could establish silencing at either replicated or non-replicated HMR loci during S phase and found that pol30 mutants were defective in establishing silencing at HMR regardless of its replication status.

Adenosine A(2A) receptors assemble into higher-order oligomers at the plasma membrane.

Oligomerization of G protein-coupled receptors (GPCRs) is known to play important roles in regulating receptor pharmacology and function. Whereas many bivalent GPCR interactions have been described, the stoichiometry and localization of GPCR oligomers are largely unknown. We have used bimolecular fluorescence complementation (BiFC) to study adenosine A(2A) receptor (A(2A)R) oligomerization.

Identification and quantification of industrial grade glycerol adulteration in red wine with fourier transform infrared spectroscopy using chemometrics and artificial neural networks.

Fourier transform infrared (FT-IR) single bounce micro-attenuated total reflectance (mATR) spectroscopy, combined with multivariate and artificial neural network (ANN) data analysis, was used to determine the adulteration of industrial grade glycerol in selected red wines. Red wine samples were artificially adulterated with industrial grade glycerol over the concentration range from 0.1 to 15% and calibration models were developed and validated.

Floral classification of honey using mid-infrared spectroscopy and surface acoustic wave based z-Nose Sensor.

Fourier transform infrared spectroscopy (FTIR) and z-Nose were used as screening tools for the identification and classification of honey from different floral sources. Honey samples were scanned using microattenuated total reflectance spectroscopy in the region of 600-4000 cm(-1). Spectral data were analyzed by principal component analysis, canonical variate analysis, and artificial neural network for classification of the different honey samples from a range of floral sources.