Spatio-Temporal Patterns and Impacts of Sediment Variations in Downstream of the Three Gorges Dam on the Yangtze River, China

Spanning the Yangtze River of China, the Three Gorges Dam (TGD) has received considerable concern worldwide with its potential impacts on the downstream side of the dam. This work investigated the spatio-temporal variations of suspended sediment concentration (SSC) at the downstream section of Yichang-to-Chenglingji from 2002 to 2015. A random forest model was developed to estimate SSC using MODIS ground reflectance products, and the spatio-temporal distributions of SSC were retrieved with this model to investigate the characteristics of water-silt variation. Our results revealed that, relatively, SSC before 2003 was evenly distributed in the downstream Yangtze River, while this spatial distribution pattern changed ce 2003 when the dam started storing water. Temporally, the SSC demonstrated a W-shaped curve of seasonal variation as one peak occurred in September and two troughs in March and November, and showed a significantly decreasing trend after three-stage impoundment. After official operation of the TGD in 2009, the SSC was reduced by over 40% than before 2003. Spatially, the most significant changes occurred in the upper Jingjiang section, where the SSC dropped by 45%. During all stages of impoundment, the water impoundment to 135 m in 2003 had the most significant impact on suspended sediment. The decreased SSC has led to emerging risks of bank failure, aggravated erosion of water front and aggressive down-cutting erosion along the downstream of the dam, as well as other ecological and environmental issues that require urgent attention by the government

Flooding Depth and Flooding Duration with the Zonation of Riparian Plant Communities in the Three Gorges Reservoir of China

The hydraulics of flows, especially the flooding process, influence the patterns of riparian plant zonation. Different characteristics of the flooding process should be analyzed to correlate plant zonation with flooding due to their different effect modes. The effects of flooding characteristics on riparian plants have yet to be studied, especially in the field. Thus, two elements of the flow regime, flooding duration and depth, were analyzed in relation to the riparian plants of the Three Gorges Reservoir. The taxonomic indices and the functional diversity of the riparian plants in three seasons in 2019 and the corresponding inundation character were surveyed. Our results showed that the riparian plant diversity and functional diversity varied by season. A significant negative relationship between plant diversity and flooding depth was observed, while flooding duration was not a significant predictor in different seasons. The greater explanatory capacity of flooding depth than that of flooding duration suggests that flooding depth could be a better indicator of the zonation of the riparian vegetation in this area. Concerning the vital component of flow hydraulics, growing opportunities to study flooding depth and strategies that consider both flooding time and flooding depth in a reservoir should be offered, as they will assist in refining process-based river restoration

Characterization of Sin1 Isoforms Reveals an mTOR-Dependent and Independent Function of Sin1γ.

Sin1 or MAPKAP1 is a key component of mTORC2 signaling complex which is necessary for AKT phosphorylation at the S473 and T450 sites, and also for AKT downstream signaling as well. A number of Sin1 splicing variants have been reported that can produce different Sin1 isoforms due to exon skipping or alternative transcription initiation. In this report, we characterized four Sin1 isoforms, including a novel Sin1 isoform due to alternative 3' termination of the exon 9a, termed Sin1γ. Sin1γ expression can be detected in multiple adult mouse tissues, and it encodes a C-terminal truncated protein comparing to the full length Sin1β isoform. In contrast to Sin1β, Sin1γ overexpression in Sin1 deficient mouse embryonic fibroblasts has no significant impact on mTORC2 activity or mTORC2 subunits protein level, although it still can interact with mTORC2 components. More interestingly, Sin1γ was detected in a specific cytosolic location with a distinct feature in structure, and its localization was transiently disrupted during cell cycle. Therefore, Sin1γ is a novel Sin1 isoform and may have distinct properties in cell signaling and intracellular localization from other Sin1 isoforms

Low Iodine Intake May Decrease Women’s Fecundity: A Population-Based Cross-Sectional Study

Salt iodization is one of the most cost-effective strategies to eliminate iodine deficiency disorders (IDD). However, China’s dismantling of salt monopoly has reduced the availability of iodized salt in the susceptible population in pregnancy, which might cause IDD and have adverse health effects on both themselves and their offspring. The aim of our study was therefore to explore the association between IDD and women’s reproductive health. This is a population-based cross-sectional study conducted in 2018 in Zhejiang Province, China. A total of 1653 pregnant women participated in this study. Median urinary iodine concentration (UIC) in the population was used to assess iodine intake. Cox regression analyses were used to estimate the association between iodine intake and time to pregnancy, which was indicated with fecundability ratio (FR) and 95% confidence interval (CI). The percentage of participants with iodine deficiency who had been waiting longer than 13 months to get pregnant (20%; median UIC 119.6 μg/L) was significantly higher than those with iodine sufficiency (14%; median UIC 147.1 μg/L). A significant decrease in fecundity was observed in participants with iodine deficiency (FR, 0.820; 95% CI, 0.725−0.929) than those with iodine sufficiency. These findings indicate the importance of ongoing monitoring of iodine nutrition in women of reproductive age. Keeping a safe and optimal level of iodine nutrition during pregnancy should be emphasized

Characterization of Sin1 isoforms.

<p>A. Schematic map representing of the human Sin1 gene and transcript variants described in this study. There are five Sin1 transcript variants generating four distinct protein isoforms. Two transcript variants encode for Sin1δ. The green and red solid regions represent start and stop codon respectively. B. Sin1 isoforms are widely express in mouse tissues. Total RNA extracted from mice tissues were analyzed by RT-PCR using either Sin1γ specific primers or primers recognized all four isoforms, 18s RNA were used as loading control. Amplified products were separated by electrophoresis in a 2% agarose gel stained with gel red, demonstrating that all four Sin1 isoforms are widely expressed in mice tissues.</p

Restoration of Sin1-/- MEFs with GFP-Sin1 expression vectors.

<p>A. Sin1 isoforms exert distinct functions in restoration of mTORC2 signaling. Sin1-/- MEF cells transfected with GFP empty vector, GFP-Sin1α, GFP-Sin1β, GFP-Sin1γ, GFP-Sin1δ respectively were grown in starved, or starved then restimulated with insulin or serum for 15min. Total cell lysates were analyzed for indicated proteins by immunoblotting. B. The MAPK pathway is not altered in Sin1 isoform-rescued Sin1-/- MEF cells. Sin1-/- MEF cells transfected with GFP empty vector, GFP-Sin1α, GFP-Sin1β, GFP-Sin1γ, GFP-Sin1δ respectively were grown in starved, or starved then restimulated with insulin or serum for 15min. Total cell lysates were analyzed for indicated proteins by immunoblotting. Single-letter abbreviations for the treatments are as follows: S, starvation for 12hr, I, insulin for 15min after starvation, F, FBS for 15min after starvation. C. The quantifications analysis of the phosphor-PKC band are shown.</p

Sin1 isoforms except Sin1δ form mTORC2 complex.

<p>A. Rictor pulled down Sin1α, Sin1β, Sin1γ, but not Sin1δ. HEK-293T cells were transiently transfected for 24h with HA-Sin1 isoform plasmids. Cell lysates (left-hand side) and rictor immunoprecipitates (right-hand side) were analyzed for mTOR, rictor and HA by western blotting. B. Sin1α, Sin1β, Sin1γ, but not Sin1δ could pull down rictor and mTOR. HEK-293T cells were transiently transfected for 24h with HA-Sin1 isoform plasmid respectively. Cell lysates (left-hand side) and HA immunoprecipitates (right-hand side) were analyzed for mTOR, rictor and HA by western blotting. All experiments were repeated for three times with the same results.</p