Search

Objective To develop an MATLAB algorithm for the automated measurement of motor neuron (MN) neurites and apply this algorithm to evaluate the organophosphate flame retardant tris (2-chloroethyl) phosphate (TCEP) on the growth of MN neurites. Methods Human embryonic stem cells were induced to gradually differentiate into MN. After the neurites were labelled with βⅢ-tubulin for fluorescence image processing, an image process algorithm was developed to automatically analyze the neurite and changes in neurite network area after pollutant treatment. During MN differentiation, the cells were treated with different concentrations of TCEP (0, 25, 50 and 100 μmol/L). Results MNs were successfully induced with the expression of choline acetyltransferase. The developed image recognition algorithm could analyze images in batches, and calculate the pixel area occupied by neural network, and reserve weak neurites by optimizing neurite retention threshold to improve the accuracy of measurement. The quantification data from image process algorithm showed that TCEP significantly decreased the percentage of neurite network area since the dose started from 50 μmol/L (P < 0.05). Conclusion An image process algorithm is successfully developed for automated measurement of neurites based on the human MN neurite model. Moreover, this algorithm can be applied to the toxicity assessment of TCEP.

Malignant tumors are common diseases that threaten human health. Early diagnosis and complete resection can significantly improve the prognosis of patients with malignant tumors. At present, the imaging techniques used clinically for malignant tumor detection have problems such as poor sensitivity and temporal-spatial resolution, long scanning time, etc., which cannot achieve early diagnosis and meet the requirements of surgical navigation. As a new imaging technology with excellent imaging characteristics, fluorescence imaging can perform real-time imaging of the structure and function of biological tissues and organs. It can realize the accurate detection of malignant tumors by designing fluorescent probes with high sensitivity, high selectivity and specificity. The sensitivity of fluorescence imaging mainly depends on the fluorophore of the probe, and the selectivity and specificity mainly depend on whether the probe adopts an effective targeting strategy. Studies have shown that near infrared fluorophores with emission wavelengths in the near infrared window, especially those in the near infrared Ⅱ window, have excellent optical properties, which can effectively improve the sensitivity of fluorescence imaging of malignant tumors; at the same time, based on the unique structure and metabolic features of malignant tumors, various targeting strategies have been developed to design "always-on" fluorescent probes and "turn-on" fluorescent probes, which significantly improved the selectivity and specificity of fluorescent imaging of malignant tumors. In this paper, the newly developed near infrared fluorophores and the strategies of fluorescent probes targeting malignant tumors are reviewed.

Valproic acid (VPA), a clinically approved small molecule, has been reported to activate Wnt signalling that is critical for dorsal–ventral (DV) patterning of neural tube. However, little is known about the impact of VPA on DV patterning process. Here, we show that even though VPA has a negative impact on the early formation of human neural tube organoids (hNTOs), it significantly enhances the efficiency of ventrally patterned hNTOs, when VPA is added during the entire differentiation process. RNA sequencing and RT‐qPCR analysis demonstrates VPA activates endogenous Wnt signalling in hNTOs. Surprisingly, transcriptome analysis also identifies upregulation of genes for degradation of GLI2 and GLI3 proteins, whose truncated fragment are transcriptional repressors of Shh signalling. The Western‐blot analysis confirms the increase of GLI3R proteins after VPA treatment. Thus, VPA might enhance ventral patterning of hNTOs through both activating Wnt, which can antagonise Shh signalling by inducing GLI3 expression, and/or inhibiting Shh signalling by inducing GLI protein degradation. We further obtain results to show that VPA still increases patterning efficiency of hNTOs with a weak influence on their early formation when the initiation time of VPA is delayed and its duration is reduced. Taken together, this study demonstrates that VPA enhances the generation of more reproducible hNTOs with ventral patterning, opening the avenues for the applications of hNTOs in developmental biology and regenerative medicine. [ABSTRACT FROM AUTHOR]

Nanotoxicology on plants has raised great concerns about the prevalence of nanoparticles (NPs) in ecosystems, and the most fundamental aspect is to assess the fate of NPs in plants. Nonetheless, the lack of high-sensitivity tracking techniques in vivo constraints intensive research on NP distribution in plants. Herein, we have overcome this limitation by first introducing persistent luminescent nanoparticles (PLNPs) as an imaging probe, which can detect the distribution of NPs in whole plants with high sensitivity by completely eliminating interference from autofluorescence. We synthesized two differently surface-charged PLNPs with excellent biosafety and then exposed these NPs to plants in the hydroponic medium. Persistent luminescence (PersL) images visually showed the disparate accumulation of PLNPs in plants. PersL signals of positively charged PLNPs were observed in the whole exposed portion of the plant roots, while negatively charged PLNPs were mainly in the root collars instead of the exposed portion. With prolonged exposure, the presence of PersL signals in leaves indicated the long-distance translocation of differently charged PLNPs from roots to leaves via hypocotyls. For further confirmation of imaging results, the distribution of NPs in plants was investigated using electron microscopy. Based on their unique optical properties, PLNPs provide a promising strategy for tracking NP's fate in plants. [ABSTRACT FROM AUTHOR]