Determination of the water-use patterns for two xerophyte shrubs by hydrogen isotope offset correction.

The stable hydrogen and oxygen isotope technique is typically used to explore plant water uptake; however, the accuracy of the technique has been challenged by hydrogen isotope offsets between plant xylem water and its potential source water. In this study, the soil hydrogen and oxygen isotope waterline was used to correct the hydrogen isotope offsets for Salix psammophila and Caragana korshinskii, two typical shrub species on the Chinese Loess Plateau. Five different types of isotopic data [(i) δ18O, (ii) δ2H, (iii) combination δ18O with δ2H, (iv) corrected δ2H and (v) combination δ18O with corrected δ2H] were separately used to determine the water-use patterns of the two shrubs. The δ2H offset values of S. psammophila and C. korshinskii did not show significant temporal variation among the sampling months (May, July and September) but showed notable differences between the two shrubs (-0.4 ± 0.5‰ in S. psammophila vs -4.3 ± 0.9‰ in C. korshinskii). The obtained water absorption proportion (WAP) of S. psammophila in the different soil layers (0-20, 20-60 and 60-200 cm) did not differ significantly among the five different input data types. However, compared with the input data types (iii) and (v), the data types (i), (ii) and (iv) overestimated the WAP of C. korshinskii in the 0-20 cm soil layer and underestimated that in the 60-200 cm layer. The data type (iii) overestimated the WAP of C. korshinskii in 0-20 cm soil layer (25.9 ± 0.8%) in July in comparison with the WAP calculated based on data type (v) (19.1 ± 1.1%). The combination of δ18O and corrected δ2H, i.e., data type (v), was identified as the best data type to determine the water use patterns of C. korshinskii due to the strong correlation between the calculated WAP and soil water content and soil sand content. In general, S. psammophila mainly used (57.9-62.1%) shallow soil water (0-60 cm), whereas C. korshinskii mainly absorbed (52.7-63.5%) deep soil water (60-200 cm). We confirm that the hydrogen isotope offsets can cause significant errors in determining plant water uptake of C. korshinskii, and provide valuable insights for accurately quantifying plant water uptake in the presence of hydrogen isotope offsets between xylem and source water. This study is significant for facilitating the application of the stable hydrogen and oxygen isotope technique worldwide, and for revealing the response mechanism of shrub key ecohydrological and physiological processes to the drought environment in similar climate regions.

Monsoonal control on a delayed response of sedimentation to the 2008 Wenchuan earthquake.

Infrequent extreme events such as large earthquakes pose hazards and have lasting impacts on landscapes and biogeochemical cycles. Sediments provide valuable records of past events, but unambiguously identifying event deposits is challenging because of nonlinear sediment transport processes and poor age control. Here, we have been able to directly track the propagation of a tectonic signal into stratigraphy using reservoir sediments from before and after the 2008 Wenchuan earthquake. Cycles in magnetic susceptibility allow us to define a precise annual chronology and identify the timing and nature of the earthquake's sedimentary record. The grain size and Rb/Sr ratio of the sediments responded immediately to the earthquake. However, the changes were muted until 2 years after the event, when intense monsoonal runoff drove accumulation of coarser grains and lower Rb/Sr sediments. The delayed response provides insight into how climatic and tectonic agents interact to control sediment transfer and depositional processes.

Upregulated circular RNA circ_0025033 promotes papillary thyroid cancer cell proliferation and invasion via sponging miR-1231 and miR-1304.

Recent evidence revealed that circular RNAs (circRNAs) are key regulators for tumorigenesis. However, their roles in papillary thyroid cancer (PTC) is not fully understood. In the current work, the differentially expressed circRNAs between PTC tissues and adjacent noncancerous tissue samples were screened by circRNA microarray. We further selected the highest expressed circRNA (circ_0025033) in tumorous tissues for the study. qRT-PCR was used to measure the level of circ_0025033 in PTC tissue samples and cell lines. Gain/loss of function assays were carried out to determine the effect of circ_0025033 on cell viability, clone-forming, apoptosis, migration and invasion. Dual-luciferase reporter assays were conducted to investigate the mechanisms of circ_0025033 in PTC. The data showed that circ_0025033 aggravated cell proliferation, migration and invasion and inhibited cell apoptosis. Additionally, circ_0025033 could directly sponge miR-1231 and miR-1304 in PTC cells. Furthermore, the oncogenic role of circ_0025033 is dependent on its suppression of miR-1231 and miR-1304. Collectively, this work uncovers a novel signal of circ_0025033/miR-1231/miR-1304 involved in PTC initiation and progression.

Overexpression of a protein disulfide isomerase-like protein from Methanothermobacter thermoautotrophicum enhances mercury tolerance in transgenic rice.

MTH1745, from thermophilic archaea Methanothermobacter thermoautotrophicum, is a protein disulfide isomerase-like protein (PDIL) with a chaperone function and disulfide isomerase activity. Mercuric cations have a high affinity for sulfhydryl groups and consequently inhibit plant growth. Disulfide compounds (e.g., copper-zinc superoxide dismutase, Cu/Zn SOD) and sulfhydryl compounds (e.g., glutathione, phytochelatins, and metallothioneins) play important roles in mercury (Hg) response. To study the relationship between Hg detoxification and PDILs, we overexpressed MTH1745 in Oryza sativa L. cv. Nipponbare by Agrobacterium-mediated transformation. The transgenic rice seedlings displayed Hg tolerance with obvious phenotypes and more effective photosynthesis compared to wild-type plants. Furthermore, lower levels of superoxide anion radicals, hydrogen peroxide, and malondialdehyde were observed in leaves or roots of transgenic plants. Antioxidant enzyme activities of superoxide dismutase and peroxidase were notably higher in transgenic seedlings under different concentrations of mercuric chloride. Moreover, increased content of non-protein thiols, reduced glutathione (GSH), and GSH/GSSG (GSSG, oxidized glutathione) ratio were also observed in the detoxification of Hg. These results indicated that heterologous expression of a PDIL from extremophiles in rice could protect the synthesis, increase stability of proteins, and enhance Hg tolerance in rice.