Activiteit

This method can measure DNA damage with a detection limit as low as 1.1 × 10-16 M, and it can distinguish DNA damage at low abundance down to 1.3 × 10-4%. Importantly, it can provide information about the occurrence of DNA damage in a specific gene and ascertain the DNA damage level in different cancer cell lines, offering a new approach for studying the physiological function of various DNA damages in human diseases.In this study, a novel method for the direct coupling of metal probe microextraction (MPME) and a dielectric barrier discharge ionization (DBDI) source with mass spectrometry (MS) is reported. Analytes adsorbed on a tungsten needle were directly transferred to the DBDI source via rapid thermal desorption, which resulted in a limit of detection as low as 8 pg/mL. This is in part due to the “active capillary” configuration of the plasma ion source, where the efficiency of ion transfer to the MS is ∼100%. Specialty gases to maintain the plasma and carry analytes to the MS are not required. In contrast to direct one-step ionization of molecular adsorbates, the complete separation of the analyte desorption from the probe and the ionization event in our experimental setup greatly enhanced the sensitivity and detection reproducibility (RSD of 8.3%). We show detection of pyrimethamine, a first-line drug for the treatment and prevention of Plasmodium falciparum malaria all over the world, by this MPME/DBDI/MS method. The detection of drug residues in live fish and paramecium was achieved without the need for any sample pretreatment. The relative concentration of the drug in different organs of the fish was determined. This simple and convenient method has the potential for the analysis of chemicals even in single-cell organisms.Abnormally increased reactive oxygen species (ROS) are intimately related to the development and metastasis of cancer. Since hydrogen peroxide (H2O2) is a major component of ROS, molecular imaging and selective treatment in response to high H2O2 are intriguing for the management of cancers. Herein, we report novel self-assembly luminescent nanoparticles, which can be activated by H2O2, thereby serving as an effective nanotheranostics for luminescence imaging and in situ photodynamic therapy (PDT) of tumors with high H2O2. This functional nanomedicine was assembled from an amphiphilic conjugate (defined as CLP) based on chlorin e6 (Ce6) simultaneously conjugated with luminol and poly(ethylene glycol), exhibiting a well-defined core-shell nanostructure. Upon triggering by pathologically relevant levels of H2O2, CLP nanoparticles produced luminescence due to the luminol unit and simultaneous excitation of Ce6 by chemiluminescence resonance energy transfer, enabling in vitro and in vivo imaging of tumors with highly expressed H2O2. In addition, excited Ce6 can produce singlet oxygen (1O2) for in situ PDT of H2O2-high tumors and inhibiting lung metastasis, which was demonstrated by in vitro and in vivo experiments. Furthermore, preliminary studies revealed the biosafety of CLP nanoparticles. Consequently, the self-illuminating nanoparticles are promising for noninvasive imaging and therapy of tumors with high expression of H2O2.Corky ringspot (CRS) is a widespread potato tuber necrotic disease caused by Tobacco rattle virus (TRV) infection. In the Pacific Northwest, this virus is transmitted by the stubby root nematode (SRN) within the genus Paratrichodorus. Remediating CRS affected fields is a major challenge that can be mitigated by growing plant varieties that are resistant to TRV infection. Growing alfalfa has been shown to reduce TRV levels in CRS infested fields over time but the development of a potato cultivar with these same capabilities would be of great economic benefit to potato growers. Castle Russet is a new potato clone that does not develop symptoms of CRS disease. ML385 concentration To assess its ability to reduce soil virus load, Castle Russet, tobacco var. “Samsun NN”, alfalfa var. “Vernema”, and Russet Burbank potato were grown for a period of 1 to 3 months in soils containing viruliferous SRN populations at two different inoculation pressures (60 nematodes/pot and 1060 nematodes/pot) in greenhouse pot experiments. SRN population size and the presence of TRV were assessed over several months post inoculation. Results indicate that plant host and length of exposure significantly influence SRN population dynamics, whereas the TRV infection status of bait plants was significantly affected by both of these factors as well as inoculation pressure. These results suggest that both alfalfa var. “Vernema” and Castle Russet are resistant to TRV infection and may potentially be used to eliminate the virus from fields affected by CRS.SIGNIFICANCE Photobiomodulation is a well-established therapeutic modality. However, the mechanism of action is poorly understood, due to lack of research in the causal relationship between the near-infrared (NIR) light irradiation and its specific biological effects, hindering broader applications of this technology. AIM Since biological chromophores typically show several absorption peaks, we determined whether specific effects of photobiomodulation are induced with a combination of two wavelengths at a certain range of irradiance only, rather than a single wavelength of NIR light. APPROACH In order to analyze a wide array of combinations of multispectral NIR light at various irradiances efficiently, we developed a new optical platform equipped with two distinct wavelengths of NIR lasers by high-throughput multiple dosing for single-cell live imaging. Two wavelengths of 1064 and 1270 nm were selected based on their photobiomodulatory effects reported in the literature. RESULTS A specific combination of wavelengths at low irradiances (250 to 400  mW  /  cm2 for 1064 nm and 55 to 65  mW  /  cm2 for 1270 nm) modulates mitochondrial retrograde signaling, including intracellular calcium and reactive oxygen species in T cells. The time-dependent density functional theory computation of binding of nitric oxide (NO) to cytochrome c oxidase indicates that the illumination with NIR light could result in the NO release, which might be involved in these changes. CONCLUSIONS This optical platform is a powerful tool to study causal relationship between a specific parameter of NIR light and its biological effects. Such a platform is useful for a further mechanistic study on not only photobiomodulation but also other modalities in photomedicine.