Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hydroxyapatite (HAP: Ca10(PO4)6(OH)2) is a widely used biocompatible material; however, information on the reaction mechanism between HAP and microorganisms is insufficient. This study aimed to identify a stable reference gene for studying the antibacterial activity of HAP. The half maximal inhibitory concentration (C50) and gene expression of a human symbiotic Escherichia coli strain TOP10, was investigated at various concentrations of HAP. Our uniformly sized HAP nanoparticles (HANPs) had a high surface area and an estimated IC50 of 75 mg/mL. The expressions of genes, including those of DNA polymerase I (poIA), DNA polymerase II (poIB), cytochrome d complex (cyd), glucan biosynthesis protein G (mdoG), D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH), and 16S ribosomal RNA (16S rRNA), were analyzed by performing quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and using reported and newly designed primers. The changes in the copy numbers compared to non-HANPs-treated conditions for polB, cyd, mdoG, GAPDH, and 16S rRNA were 50%-381%, 0.7%-66.3%, 1.1%-7.8%, 1.6%-86.3%, and 0.3%-8.1%, respectively. The expressions of polA remained stable under all conditions (62.8%-88.4%). Therefore, we identified polA as a suitable reference gene. Moreover, the expressions of cyd and mdoG were inhibited, indicating that the antibacterial activity of HANPs is related to cell membrane or cell wall proteins. Our findings provide a thorough understanding of HAP-microorganism interactions for potential biomedical applications.
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PMID:Gene polA as a Suitable Reference for Studying Antibacterial Effect of Hydroxyapatite. 2634 2

We report the discovery that strains of Staphylococcus epidermidis produce 6-N-hydroxyaminopurine (6-HAP), a molecule that inhibits DNA polymerase activity. In culture, 6-HAP selectively inhibited proliferation of tumor lines but did not inhibit primary keratinocytes. Resistance to 6-HAP was associated with the expression of mitochondrial amidoxime reducing components, enzymes that were not observed in cells sensitive to this compound. Intravenous injection of 6-HAP in mice suppressed the growth of B16F10 melanoma without evidence of systemic toxicity. Colonization of mice with an S. epidermidis strain producing 6-HAP reduced the incidence of ultraviolet-induced tumors compared to mice colonized by a control strain that did not produce 6-HAP. S. epidermidis strains producing 6-HAP were found in the metagenome from multiple healthy human subjects, suggesting that the microbiome of some individuals may confer protection against skin cancer. These findings show a new role for skin commensal bacteria in host defense.
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PMID:A commensal strain of Staphylococcus epidermidis protects against skin neoplasia. 3153 21