In 1998, a amovie entitled "A Civil Action" was released. The movie described the Woburn case, begun in 1982 and concluded in 1990, one of the most famous cases of trichloroethylene pollution. In a small town near Boston, twelve children died of leukemia, which seemed attributable to trichloroethylene contamination of the drinking water. The victims, however, could not win the case, since evidence that the identified chemicals could cause leukemia and other human illnesses was rather sketchy. There have been many cases of trichloroethylene pollution in industrial nations including Japan, therefore, we reconsidered the missing link. Our conclusion is that the disease occurred not by a direct effect of the chemical hazard on biological macromolecules but by an indirect effect through the physiological system such as signal transduction and transcriptional regulation. In 1984, we reported a marked reduction in the regulatory heme pool by trichloroethylene exposure, however, the biological significance was not well understood. Recently, we found that the DNA binding activity of Bach1, a negative regulator of genes, is controlled by heme, the regulation of which seems to explain how leukemia develops. The heterodimer of Bach1 with MafK recognizes Maf recognition elements (MAREs) competing with the erythroid type positive regulator, a complex of NF-E2 with MafK. Bach1/MafK occupies MAREs under lower heme conditions, whereas MAREs are open to NF-E2/MafK along with increasing heme concentration. Since the NF-E2/MafK function is closely related to normal erythroid differentiation, of which disorders such as sideroblastic anemia are often related to neoplasia; i.e., a clonal disorder that can progress to leukemia. Thus, a marked decline in regulatory heme by trichloroethylene intoxication could be one of the pathways to leukemia.
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http://dx.doi.org/10.1265/ehpm.2002.103 | DOI Listing |
Plant Physiol Biochem
January 2025
Laboratory of Microbial Genetics, Department of Botany, Institute of Science, Banaras Hindu University, Varanasi, 221005, India. Electronic address:
Nitric oxide synthases (NOSs) are heme-based monooxygenases that catalyze the NADPH-dependent oxidation of L-arginine to produce NO and L-citrulline. Over the past five years, the identification and characterization of NOS homologs in cyanobacteria have significantly advanced our understanding of these enzymes. However, the precise mechanisms through which NOS-derived NO influences nitrogen metabolism remain incompletely elucidated.
View Article and Find Full Text PDFJ Integr Plant Biol
January 2025
Key Laboratory of Photobiology, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, China.
Plants, algae and photosynthetic bacteria convert light into chemical energy by means of photosynthesis, thus providing food and energy for most organisms on Earth. Photosynthetic pigments, including chlorophylls (Chls) and carotenoids, are essential components that absorb the light energy necessary to drive electron transport in photosynthesis. The biosynthesis of Chl shares several steps in common with the biosynthesis of other tetrapyrroles, including siroheme, heme and phycobilins.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Plant and Microbial Biology, University of Zurich, Zollikerstrasse 107, Zürich, 8008, Switzerland.
Burkholderia cenocepacia H111 is an obligate aerobic bacterium which has been isolated from a cystic fibrosis (CF) patient. In CF lungs the environment is considered micro-oxic or even oxygen-depleted due to bacterial activities and limited oxygen diffusion in the mucus layer. To adapt to low oxygen concentrations, bacteria possess multiple terminal oxidases.
View Article and Find Full Text PDFBone Res
January 2025
Department of Internal Medicine 3, Friedrich-Alexander-University Erlangen-Nürnberg (FAU) and Universitätsklinikum Erlangen, Erlangen, Germany.
Osteocytes are the main cells in mineralized bone tissue. Elevated osteocyte apoptosis has been observed in lytic bone lesions of patients with multiple myeloma. However, their precise contribution to bone metastasis remains unclear.
View Article and Find Full Text PDFJ Biochem Mol Toxicol
January 2025
Department of Medical Biochemistry, Faculty of Medicine, Aksaray University, Aksaray, Turkey.
Ovarian ischemia is a pathological condition that usually occurs due to ovarian torsion, resulting in the interruption of blood supply to the ovaries and oxygen deficiency. Silymarin (SLM) is a flavonoid complex of plant origin with pharmacological properties such as antioxidant, anti-inflammatory, and antiapoptotic effects. In this study, we investigated the effects of SLM through different pathways in rats subjected to experimental ovarian ischemia/reperfusion (I/R).
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