Revealing the effects of ligands of silver nanoclusters on the interactions between them and ctDNA: Abstraction to visualization

Silver nanoclusters (AgNCs) have been widely applied in the field of biology, drug therapy and cell imaging in the last decade. In order to study the biosafety of AgNCs, GSH-AgNCs and DHLA-AgNCs were synthesized using glutathione (GSH) and dihydrolipoic acid (DHLA) as ligands, and their interactions with calf thymus DNA (ctDNA) from abstraction to visualization were studied. The results of spectroscopy, viscometry and molecular docking demonstrated that GSH-AgNCs mainly bound to ctDNA in a groove mode, while DHLA-AgNCs were both groove and intercalation binding. Fluorescence experiments suggested that the quenching mechanism of both AgNCs to the emission of ctDNA-probe were both in static mode, and thermodynamic parameters demonstrated that the main forces between GSH-AgNCs and ctDNA were hydrogen bonds and van der Waals forces, while hydrogen bonds and hydrophobic forces contributed to the binding of DHLA-AgNCs to ctDNA. The binding strength demonstrated that DHLA-AgNCs bound to ctDNA more strongly than that of GSH-AgNCs. The results of circular dichroism (CD) spectroscopy reflected small effects of both AgNCs on the structure of ctDNA. This study will support the theoretical foundation for the biosafety of AgNCs and have a guiding significance for the preparation and application of AgNCs.

Prevalence and correlates of alcohol use and subsequent sexual activity among adult males in a rural community of ethnic minorities in Yunnan Province, China

This community-based cross-sectional study examined alcohol use and HIV risks among a sample of predominantly ethnic males in Yunnan Province, China. Information about alcohol use, sexual behavior, sex after drinking, and HIV infection was collected using face-to-face interviews and blood testing. Out of 497 potential male participants, 382 males agreed to participate in this study. Of these males, 70% were ethnic minorities, 74.1% were currently married, 95.5% were sexually experienced, 27.5% had used drugs, and 6% were HIV-infected. Over 81% were current drinkers and 55.7% started drinking before the age of 18. Among current drinkers, 44.5% drank daily and 31.9% had drunk heavily in the past 30 days. Baijiu (a Chinese liquor distilled from sorghum with an ethanol content of at least 40%) was the preferred drink of choice. Excessive alcohol use was associated with being an ethnic Jingpo (OR = 1.96), being a smoker (OR = 2.09) and having multiple lifetime sex partners (OR = 1.55). Over 21% reported having ever engaged in sex after drinking. Those who were aged 26 to 35 (OR = 3.80), started drinking before age 18 (OR = 2.14), who were heavy drinkers (OR = 1.99), or who had ever used drugs (OR = 2.00) were more likely to have ever engaged in sex after drinking. Health education programs for alcohol abuse and unwanted outcomes, particularly the risk of HIV, are urgently needed for ethnic males in Yunnan.