Deciphering repair pathways of clustered DNA damage in human TK6 cells: insights from atomic force microscopy direct visualization.

Ionizing radiation induces various types of DNA damage, and the reparability and lethal effects of DNA damage differ depending on its spatial density. Elucidating the structure of radiation-induced clustered DNA damage and its repair processes will enhance our understanding of the lethal impact of ionizing radiation and advance progress toward precise therapeutics. Previously, we developed a method to directly visualize DNA damage using atomic force microscopy (AFM) and classified clustered DNA damage into simple base damage clusters (BDCs), complex BDCs and complex double-strand breaks (DSBs).

A Supramolecular Biosensor for Rapid and High-Throughput Quantification of a Disease-Associated Niacin Metabolite.

Metabolic abnormalities play a pivotal role in various pathological conditions, necessitating the quantification of specific metabolites for diagnosis. While mass spectrometry remains the primary method for metabolite measurement, its limited throughput underscores the need for biosensors capable of rapid detection. Previously, we reported that pillar[6]arene with 12 carboxylate groups (P6AC) forms host-guest complexes with 1-methylnicotinamide (1-MNA), which is produced in vivo by nicotinamide -methyltransferase (NNMT).

Case Report: Recent Case Reports of Levant Blunt-Nosed Viper Macrovipera lebetina obtusa Snakebites in Iran.

Envenomation and death resulting from snakebites represent a significant public health problem worldwide, particularly in tropical and subtropical regions. The WHO has defined snakebite as a neglected tropical health concern. Bites from Macrovipera lebetina obtusa usually cause life-threatening systemic hemodynamic disturbances, reduced functionality of the kidneys, and other serious symptoms, including hypotension shock, edema, and tissue necrosis, at the bite site.

Participation of TDP1 in the repair of formaldehyde-induced DNA-protein cross-links in chicken DT40 cells.

Proteins are covalently trapped on DNA to form DNA-protein cross-links (DPCs) when cells are exposed to DNA-damaging agents. Aldehyde compounds produce common types of DPCs that contain proteins in an undisrupted DNA strand. Tyrosyl-DNA phosphodiesterase 1 (TDP1) repairs topoisomerase 1 (TOPO1) that is trapped at the 3'-end of DNA.

Comparative study of the in vivo toxicity and pathophysiology of envenomation by three medically important Egyptian snake venoms.

Snakebite envenomation is a serious medical problem in many developing tropical and subtropical countries. Envenomation is registered by the World Health Organization as a neglected tropical disease due to critical shortages in the production of antivenom. Envenomation causes more than 100,000 deaths annually.

DNA-protein cross-links: Formidable challenges to maintaining genome integrity.

DNA is associated with proteins that are involved in its folding and transaction processes. When cells are exposed to chemical cross-linking agents or free radical-generating ionizing radiation, DNA-associated proteins are covalently trapped within the DNA to produce DNA-protein cross-links (DPCs). DPCs produced by these agents contain cross-linked proteins in an undisrupted DNA strand.

Radiation-induced DNA-protein cross-links: Mechanisms and biological significance.

Ionizing radiation produces various DNA lesions such as base damage, DNA single-strand breaks (SSBs), DNA double-strand breaks (DSBs), and DNA-protein cross-links (DPCs). Of these, the biological significance of DPCs remains elusive. In this article, we focus on radiation-induced DPCs and review the current understanding of their induction, properties, repair, and biological consequences.

Aldehydes with high and low toxicities inactivate cells by damaging distinct cellular targets.

Aldehydes are genotoxic and cytotoxic molecules and have received considerable attention for their associations with the pathogenesis of various human diseases. In addition, exposure to anthropogenic aldehydes increases human health risks. The general mechanism of aldehyde toxicity involves adduct formation with biomolecules such as DNA and proteins.

Induction of DNA-protein cross-links by ionizing radiation and their elimination from the genome.

Ionizing radiation produces various types of DNA lesions, such as base damage, single-strand breaks, double-strand breaks (DSBs), and DNA-protein cross-links (DPCs). Of these, DSBs are the most critical lesions underlying the lethal effects of ionizing radiation. With DPCs, proteins covalently trapped in DNA constitute strong roadblocks to replication and transcription machineries, and hence can be lethal to cells.

Translocation and stability of replicative DNA helicases upon encountering DNA-protein cross-links.

DNA-protein cross-links (DPCs) are formed when cells are exposed to various DNA-damaging agents. Because DPCs are extremely large, steric hindrance conferred by DPCs is likely to affect many aspects of DNA transactions. In DNA replication, DPCs are first encountered by the replicative helicase that moves at the head of the replisome.

Detection of DNA-protein crosslinks (DPCs) by novel direct fluorescence labeling methods: distinct stabilities of aldehyde and radiation-induced DPCs.

Proteins are covalently trapped on DNA to form DNA-protein crosslinks (DPCs) when cells are exposed to DNA-damaging agents. DPCs interfere with many aspects of DNA transactions. The current DPC detection methods indirectly measure crosslinked proteins (CLPs) through DNA tethered to proteins.

Repair and biochemical effects of DNA-protein crosslinks.

Genomic DNA is associated with various structural, regulatory, and transaction proteins. The dynamic and reversible association between proteins and DNA ensures the accurate expression and propagation of genetic information. However, various endogenous, environmental, and chemotherapeutic agents induce DNA-protein crosslinks (DPCs), and hence covalently trap proteins on DNA.

Ultrastructural changes in the muscles, midgut, hemopoietic organ, imaginal discs and Malpighian tubules of the mosquito Aedes aegypti larvae infected by the fungus Coelomomyces stegomyiae.

Fungi belonging to the genus Coelomomyces can infect mosquito larvae and develop within the larval hemocoel. To examine fungal development, Aedes aegypti larvae infected with Coelomomyces stegomyiae Keilin were fixed, embedded and sectioned for both light and electron microscopy. While fungal hyphae of C.