involvement of host-derived signals in the regulation of non-autonomous xylem vessel differentiation and suggest that its connection to the host xylem during the haustorium development activates a set of key genes for differentiation into xylem vessel cells.Keywords: stem parasitic plant, plant-plant interspecific interaction, haustorium development, xylem vessel differentiation, transcriptome analysis Kaga et al.

Calreticulin (CRT), a chaperone typically located in the endoplasmic reticulum (ER), is known to translocate to the cell surface in response to anticancer drugs. Cell surface CRT (ecto-CRT) on apoptotic or pre-apoptotic cells serves as an “eat me” signal that can promote phagocytosis. In this study, we observed the biphasic (early transient and late sustained) increase of ecto-CRT on HT-29 cells after treatment with oxaliplatin (L-OHP). To investigate the role of ecto-CRT that accumulates in the early and late phases as “eat me” signals, we examined the phagocytosis of HT-29 cells by macrophage-like cells and dendritic cell (DC) -like cells prepared from THP-1 cells. The results indicated that the early ecto-CRT-expressed cells were phagocytosed by immature DC-like cells, and the late ecto-CRT-expressed cells were phagocytosed primarily by macrophage-like cells, while mature DC-like cells did not respond to the either class of ecto-CRT-expressed cells. Both types of phagocytotic events were inhibited by CRT Blocking Peptide, suggesting that such events depended on the ecto-CRT. Our results suggested that the early increase of ecto-CRT is related to phagocytosis as part of immunogenic cell death (ICD), while the late increase of ecto-CRT is related to the removal of apoptotic cells by macrophages.

Recently, ultra-low eld MRI (ULF-MRI) has attracted attention as a medical imaging technique. In ULF-MRI, because nuclear magnetization is very weak, hyperpolarized nuclear magnetization is expected to increase the intensity of MR signals. The use of hyperpolarized xenon gas, which has substantially larger polarization ratio than protons, has been proposed. However, MR signals decay rapidly when a large gradient eld is used in MR signal detection. Meanwhile, the sweep imaging with Fourier transformation (SWIFT) approach, which utilizes an adiabatic radio frequency pulse with amplitude and frequency modulations and small gradient eld, has been proposed. In this study, we evaluated the in uence of the parameters used in the SWIFT approach on hyperpolarized xenon imaging in ULF-MRI. To simulate signal reconstruction of hyperpolarized xenon with the SWIFT approach, we calculated motions of magnetization according to the Bloch equation using a fourth-order Runge-Kutta method. Two pyramidal pro les with widths of 25 and 75 mm were simulated as nuclear magnetization density proles. The motions of magnetization and the acquired MR signals caused by magnetization were subsequently computed using various parameters comprising sampling points, bandwidth, and duration of excitation. The signals were nally reconstructed using a cross-correlation method. The results indicated that reconstructed signals could be calculated from the MR signals acquired by the SWIFT approach at a bandwidth of 1, 10 or 100 kHz and a matrix size of 100, 200 or 400. However, signals reconstructed using a bandwidth of 1 kHz or a matrix size of 100 were distorted near the position where the signal changed. These results suggest that a wide bandwidth (≥10 kHz) and a large matrix size (≥200) should be used for better signal reconstruction from the MR signals acquired by the SWIFT approach, and that the Larmor frequency of ULF-MRI should be greater than 10 kHz to achieve wide bandwidth. In addition, DC component distortions in the reconstructed signals increased when distribution of nuclear magnetization density in the eld-of-view (FOV) was large. Therefore, a wide FOV should be selected to reduce DC component distortions.