Three-dimensional nanoscale analysis of light-dependent organelle changes in Arabidopsis mesophyll cells

一つの植物細胞を丸ごと3次元で再現 --光依存的なオルガネラの変化をナノスケールで探る--. 京都大学プレスリリース. 2022-10-19.Different organelles function coordinately in numerous intracellular processes. Photorespiration incidental to photosynthetic carbon fixation is organized across three subcellular compartments: chloroplasts, peroxisomes, and mitochondria. Under light conditions, these three organelles often form a ternary organellar complex in close proximity, suggesting a connection with metabolism during photorespiration. However, due to the heterogeneity of intercellular organelle localization and morphology, organelles' responses to changes in the external environment remain poorly understood. Here we used array tomography by field emission scanning electron microscopy to image organelles inside the whole plant cell at nanometer resolution, generating a three-dimensional (3D) spatial map of the light-dependent positioning of chloroplasts, peroxisomes, nuclei, and vacuoles. Our results show, in light-treated cells, the volume of peroxisomes increased, and mitochondria were simplified. In addition, the population of free organelles decreased, and the ternary complex centered on chloroplasts increased. Moreover, our results emphasized the expansion of the proximity area rather than the increase in the number of proximity sites inter-organelles. All of these phenomena were quantified for the first time on the basis of nanoscale spatial maps. In summary, we provide the first 3D reconstruction of Arabidopsis mesophyll cells, together with nanoscale quantified organelle morphology and their positioning via proximity areas, and then evidence of their light-dependent changes

An autopsy case of familial amyotrophic lateral sclerosis and dementia with p.R487H VCP gene mutation

We described an autopsied case of amyotrophic lateral sclerosis (ALS)-dementia with p.R487H mutation in the VCP gene. TDP-43-positive neuronal cytoplasmic inclusions (NCI), neuronal intranuclear inclusions (NII) and glial cytoplasmic inclusions were observed in the brain. The frequency of NCI was small but equal to that of NII, an atypical finding for VCP-related disorders. In contrast, the findings in the spinal cord and brainstem closely resembled those of sporadic ALS

An autopsy case of granulocyte-colony-stimulating-factor-producing extrahepatic bile duct carcinoma

A 79-year-old man was referred to this department due to the presence of extrahepatic bile duct carcinoma with a tumor at the left chest wall. The lesion was suspected to be a metastasis of bile duct carcinoma to the left wall, however, computed tomography (CT) revealed no regional lymph node or liver metastases. In addition, cytological and pathological examinations did not show malignancy. At the time of admission, the white blood cell count was 21 460 cells/μL (neutrophils, 18 240 cells/μL) and this elevated to 106 040 before death. In addition, serum granulocyte colony-stimulating factor (G-CSF) was elevated. At 28 d after admission, the patient died. An autopsy showed a poorly differentiated adenocarcinoma with sarcomatous change, which had slightly invaded into the pancreas around the bile duct, and was found in the distal bile duct with multiple metastases to the chest wall, lung, kidney, adrenal body, liver, mesentery, vertebra and mediastinal and para-aortic lymph nodes, without locoregional lymph node and liver metastasis. The cancer cells showed positive immunohistochemical staining for anti-G-CSF antibody. This is believed to be the first report of an extrahepatic bile duct carcinoma that produces G-CSF. Since G-CSF-producing carcinoma and sarcomatous change of the biliary tract leads to poor prognosis, early diagnosis and treatment are needed. When infection is ruled out, the G-CSF in serum should be examined. In addition, examinations such as bone scintigraphy and chest CT should also be considered for distant metastasis