Rhodococcus erythropolis IMET 7185 produces an inducible cholesterol oxidase (COD) which can easily be extracted by treatment of cells with 0.1% Triton X-100. The yield of the enzyme was 3.3 U/g wet wt from induced cells, which is about 5 times more than from non-induced cells. A study of the location of COD on intact cells and on ultrathin sections by means of immunogold electron microscopy revealed the following distribution, which corresponds with the biochemical results: (1) COD, which is extractable by the detergent, was localized in a distance up to 80 nm above the cell surface. It belongs to a surface layer, which only became visible after lysine/glutaraldehyde treatment and staining with ruthenium red, indicating a high carbohydrate content. (2) Non-extractable COD was found on the cell surface in a shorter distance to the cell wall as well as within the cell wall, in the cytoplasmic membrane and in the peripheral cytoplasm. In the latter clusters of gold particles on some places suggest the presence of larger amounts of insoluble enzyme.
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http://dx.doi.org/10.1016/0960-0760(92)90028-h | DOI Listing |
Hepatol Commun
December 2024
Department of Microbiology and Immunology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA.
Background: Sphingosine-1 phosphate (S1P) is a bioactive lipid molecule that modulates inflammation and hepatic lipid metabolism in MASLD, which affects 1 in 3 people and increases the risk of liver fibrosis and hepatic cancer. S1P can be generated by 2 isoforms of sphingosine kinase (SphK). SphK1 is well-studied in metabolic diseases.
View Article and Find Full Text PDFBiochem Biophys Res Commun
January 2025
Department of Gastroenterology, Juntendo University School of Medicine, Tokyo, Japan.
Lipid rafts are subdomains of the cell membrane that are rich in cholesterol and glycolipids, and they are involved in various cellular processes and pathophysiological mechanisms. However, the specific role of lipid rafts in hepatocyte dysfunction during the pathogenesis of metabolic dysfunction-associated steatotic liver disease (MASLD) is not fully understood. In this study, we investigated the impact of lipid rafts on insulin sensitivity and hepatocyte injury induced by saturated free fatty acids (sFFAs) using primary-cultured mouse hepatocytes.
View Article and Find Full Text PDFAdv Sci (Weinh)
December 2024
Zhejiang Key Laboratory of Imaging and Interventional Medicine, Zhejiang Engineering Research Center of Interventional Medicine Engineering and Biotechnology, The Fifth Affiliated Hospital of Wenzhou Medical University, Lishui, 323000, P. R. China.
The immunosuppressive residual tumor microenvironment (IRTM) is a key factor in the high recurrence and metastasis rates of hepatocellular carcinoma (HCC) after microwave ablation (MWA). Cholesterol-rich tumor fragments significantly contribute to IRTM deterioration. This study developed a cholesterol-targeted catalytic hydrogel, DA-COD-OD-HCS, to enhance the synergy between MWA and immune checkpoint inhibitors (ICIs) for HCC treatment.
View Article and Find Full Text PDFAdv Sci (Weinh)
November 2024
Key Laboratory of Microbial Pathogenesis and Interventions of Fujian Province University, Biomedical Research Center of South China, College of Life Sciences, Fujian Normal University, 1 Keji Road, Fuzhou, 350117, P. R. China.
The dysregulated cholesterol metabolism in breast cancer cells drives malignancy, invasion, and metastasis, emphasizing the significance of reducing abnormal cholesterol accumulation for effective cancer treatment and metastasis inhibition. Despite its promise, cholesterol oxidase (ChOx) encounters challenge due to limited catalytic efficiency and susceptibility to harsh conditions. To overcome these hurdles, biocompatible nanoplatforms (Cu-HPB/C) tailored for efficient cholesterol depletion are introduced.
View Article and Find Full Text PDFFree Radic Res
October 2024
Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology, Gwangju, Republic of Korea.
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