Recent advances in bioimaging equipment have allowed for the significant and rapid acquisition of biological images. Consequently, new methods are energetically being developed to quantitatively and objectively evaluate the biological features of many bioimages. Recently, we described the application of the CARTA (Clustering-Aided Rapid Training Agent) image classification framework, which can be used to obtain highly accurate classifications of a wide variety of biomedical images. However, the efficacy of this technology in association with transmission electron microscopy (TEM) images has not been evaluated. We herein report the automatic classification of chloroplast TEM images of chloroplasts of wild-type Arabidopsis thaliana and four kinds of mutants impaired in chloroplast-targeted proteins. CARTA successfully classified the TEM images based on their genetic backgrounds. As previously reported with fluorescent microscopic and magnetic resonance images, CARTA reduced the annotation cost while maintaining accuracy. Furthermore, using images obtained with different accelerating voltages resulted in biologically meaningless classifications, suggesting that TEM settings are critical for chloroplast morphological classification. CARTA is expected to be useful for future computational inspections of the ultrastructure visualized with TEM.

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The folding of β-lactoglobulin was monitored according to the stopped-flow technique coupled with circular dichroism and fluorescence at –30℃ in the presence of a ternary solvent system (ethylene glycol 25% - methanol 20% - buffer 55%). We observed three phases, as noted in the binary solvent system (ethylene glycol 45% - buffer 55%) (Qin et al., 2001, FEBS lett., 507, 299-302). The fastest phase within the dead time of the stopped-flow apparatus (10 ms) and the second phase (3.8 s at –30℃) resulted in an increased α-helix content. The ternary solvent system is advantageous due to its lower viscosity. However, the results should be critically examined, as this system is more favorable for α-helix formation.

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Klotho is an anti-aging protein as well as a tumor suppressor. Current studies have indicated that klotho causes apoptosis by affecting the p53/p21 pathway in oxidative stress-induced cancer cells. However, the detailed cellular dynamics underlying the actions of klotho under conditions of oxidative stress in human cells are poorly understood. In this study, we examined the mechanisms and roles of klotho in oxidation-induced human lung cancer cells using immunofluorescence methods. It was incidentally found that klotho forms unique granules, which are also observed in another human lung cancer cell line and different types of human cancer cells. Additionally, the most important and multifunctional tumor-suppressor factor p53 was identified to be essential for the formation of klotho granules.

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