Sulfur dioxide enhance drought tolerance of wheat seedlings through H2S signaling.

Drought is one of the most common factors that limit plant growth and productivity. Sulfur dioxide (SO2) has recently been found to play a benefical role in protection of plants against environmental stress. In this study, we investigated the effect of SO2 on the physiological and molecular response of wheat seedlings to drought stress. Pretreatment with 10 mg/m3 SO2 significantly increased the survival rate and relative water content (RWC) of wheat seedlings under drought stress, indicating that pre-exposure to appropriate level of SO2 could enhance drought tolerance of plants. These responses were related to the enhanced proline accumulation in the drought-treated wheat seedlings that induced by SO2 pretreatment. Meanwhile, SO2 pretreatment increased the activities of superoxide dismutase (SOD) and peroxidase (POD), and effectively reduced the content of hydrogen peroxide (H2O2) and malondialdehyde (MDA) in drought-treated wheat seedlings, suggesting SO2 could alleviate drought-induced oxidative damage by enhancing antioxidant defense system in plants. Expression analysis of transcription factor genes also showed that SO2 pretreatment decreased the expression of TaNAC69, but the expression of TaERF1 and TaMYB30 changed slightly and maintained at higher levels in wheat seedlings in response to drought stress. Furthermore, SO2 pretreatment triggered marked accumulation of hydrogen sulfide (H2S) in wheat seedlings under drought stress. When scavenged H2S by spraying Hypotaurine (HT), the activities of antioxidant enzymes and the expression of transcription factor genes were decreased, and the content of H2O2 and MDA increased to the level of drought treatment alone, suggesting a regulatory role of SO2-induced H2S in plant adaptation to drought stress. Together, this study indicated that SO2 enhanced drought tolerance of wheat seedlings through H2S signaling, and provided new strategy for enhancing plant tolerance to drought stress.

Arsenic and sulfur dioxide co-exposure induce renal injury via activation of the NF-κB and caspase signaling pathway.

Although emerging evidence suggests positive association of arsenic (As) or sulfur dioxide (SO2) exposure with human diseases, reports concerning the effects of co-exposure of As and SO2 are lacking. Moreover, there is insufficient information in the literature about As and SO2 co-exposure to renal injury. In this study, we focus on the environmental problems of excessive As and SO2 that co-exist in many coal consumption areas. We used both C57BL/6 mice and 293T cells to detect toxicities of As and SO2 exposure alone or in combination. Our results showed that co-exposure significantly increased the hazard compared with exposure to As or SO2 alone. Mouse kidney tissue slices showed that co-exposure caused more severe diffuse sclerosing glomerulonephritis than As and SO2 exposure alone. Meanwhile experiments showed that apoptosis was aggravated by co-exposure of As and SO2 in 293T cells. Because As and SO2 cause cell toxicity through increasing oxidative stress, next we detected ROS and other oxidative stress parameters, and the results showed oxidative stress was increased by co-exposure compared with the other three groups. The expression levels of downstream genes in the NF-κB and caspase pathways were higher in the co-exposure group than in the groups of As or SO2 exposure alone in mice and 293T cells. Based on the above results, co-exposure could induce higher toxicity in vitro and in vivo compared with single exposure to As or SO2, indicating that people living in places that contaminated by As and SO2 may have higher chance to get renal injury.

[Research progress of ellagitannin intestinal metabolite urolithins].

Ellagitannins is a kind of phenolic compounds with many biological activities. Recent studies have found that the effective ingredients of these compounds have close relationship with their colon-derived bacteria metabolites, that is urolithins. The objective of this study was to review the structure characteristics, types and distribution of urolithins, improvement in diseases related to prostate, breast and colon, as well as anti-cancer, anti-oxidation, anti-inflammation and other biological activities. The present review will lay the foundation for development and utilization of urolithins.