202 research outputs found
The Ecological Restoration of Heavily Degraded Saline Wetland in the Yellow River Delta
As a result of discontinuous water flow, agriculture, and increasing urban use of fresh water affecting the natural wetlands of the Yellow River Delta, these areas have experienced significant degradation in the past two decades, ultimately diminishing the overall natural wetland land area in the region. This study aimed to address the issue of decreasing fresh water in the Yellow River Delta by studying the effects of three different approaches to restoration on long-term wetland recovery. The results of the study demonstrated that soil salt and available Na contents significantly decreased in response to all three restoration treatments. Impacts of the restoration treatments were more significant in 2009 than in 2010, as shown by the high rate of activity in the reed debris group. The highest phosphatase activity of the experimental period was also observed in the reed debris group. Meanwhile, a marked variation in soil nutrient elements (total carbon (TC), total nitrogen (TN), available phosphorus, and available potassium) was observed in the restoration treatment plots throughout the experimental period. TC and TN contents were generally higher in the restoration treatment groups than in the control group. Moreover, urease and phosphatase activity levels were highly correlated with one another, as well as with soil nutrient elements. In 2009, the yield of the Suaeda salsa plant was highest in the reed debris treatment group and lowest in the ploughing treatment group. The S. salsa plant did show a positive response to all of the different restoration treatments. Taken together, these results suggest that restoration approaches that implement ploughing techniques aided in the restoration of degraded saline wetlands.As a result of discontinuous water flow, agriculture, and increasing urban use of fresh water affecting the natural wetlands of the Yellow River Delta, these areas have experienced significant degradation in the past two decades, ultimately diminishing the overall natural wetland land area in the region. This study aimed to address the issue of decreasing fresh water in the Yellow River Delta by studying the effects of three different approaches to restoration on long-term wetland recovery. The results of the study demonstrated that soil salt and available Na contents significantly decreased in response to all three restoration treatments. Impacts of the restoration treatments were more significant in 2009 than in 2010, as shown by the high rate of activity in the reed debris group. The highest phosphatase activity of the experimental period was also observed in the reed debris group. Meanwhile, a marked variation in soil nutrient elements (total carbon (TC), total nitrogen (TN), available phosphorus, and available potassium) was observed in the restoration treatment plots throughout the experimental period. TC and TN contents were generally higher in the restoration treatment groups than in the control group. Moreover, urease and phosphatase activity levels were highly correlated with one another, as well as with soil nutrient elements. In 2009, the yield of the Suaeda salsa plant was highest in the reed debris treatment group and lowest in the ploughing treatment group. The S. salsa plant did show a positive response to all of the different restoration treatments. Taken together, these results suggest that restoration approaches that implement ploughing techniques aided in the restoration of degraded saline wetlands
Interplay between multiple charge-density waves and the relationship with superconductivity in PdHoTe
HoTe, a member of the rare-earth tritelluride (Te) family, and
its Pd-intercalated compounds, PdHoTe, where superconductivity (SC)
sets in as the charge-density wave (CDW) transition is suppressed by the
intercalation of a small amount of Pd, are investigated using angle-resolved
photoemission spectroscopy (ARPES) and electrical resistivity. Two
incommensurate CDWs with perpendicular nesting vectors are observed in
HoTe at low temperatures. With a slight Pd intercalation ( = 0.01),
the large CDW gap decreases and the small one increases. The momentum
dependence of the gaps along the inner Fermi surface (FS) evolves from
orthorhombicity to near tetragonality, manifesting the competition between two
CDW orders. At = 0.02, both CDW gaps decreases with the emergence of SC.
Further increasing the content of Pd for = 0.04 will completely suppress
the CDW instabilities and give rise to the maximal SC order. The evolution of
the electronic structures and electron-phonon couplings (EPCs) of the multiple
CDWs upon Pd intercalation are carefully scrutinized. We discuss the interplay
between multiple CDW orders, and the competition between CDW and SC in detail.Comment: 6 pages, 5 figure
N 2
Using static chambers and gas chromatography, nitrous oxide (N2O) fluxes from an apple orchard soil in the Bohai Bay region of China were measured from February 2010 to February 2011. In this study, two nitrogen (N) fertilizer treatments were designed—without (CK) or with (SN) synthetic N fertilizers (800 kg N ha−1). The annual cumulative N2O emissions from CK and SN were 34.6 ± 3.0 (mean ± standard error) and 44.3 ± 6.0 kg N2O–N ha−1, respectively. Such high emissions resulted from the intensive N fertilization in the experimental and previous years. The direct emission factor (EFd) of N2O induced by the applied synthetic N fertilizers was 1.2%. The EFd is within the range of previous studies carried out in other croplands, which suggests that it is reasonable to estimate regional N2O emissions from apple orchards using the EFd obtained in other croplands. In addition, significant positive correlations existed between N2O fluxes and soil temperatures or soil dissolved organic carbon contents
Effects of salt stress and nitrogen application on growth and ion accumulation of Suaeda salsa plants
Suaeda salsa is a typical pioneer species which can grow well in high salt environmental conditions. The objective of this study is to evaluate the effect of different levels of salinity (5.25, 10.5 and 21g NaCl per kg soil) and nutrient supply (0, 0.3, 0.6 and 1.2g urea per kg soil) on plant morphology, biomass, accumulation of ions and C/N ratio in leaves of S. salsa. The results showed that the plant height, number of branches, length of branches and diameter of shoot were significantly affected by salt stress, and the nitrogen released the negative effects of salt. The nitrogen treatment increased the biomass ofleaf, shoot and root. Leaf water content was significantly affected by the interaction of salt stress andnitrogen treatment. The content of Na + and Cl- increased significantly as increasing of salt, the content ofK+, Ca2+, Mg2+ and SO 42- decreased simultaneously to keep ion balance. The C/N ratio decreased significantly as increasing of nitrogen treatment. The content of proline increased significantly with the increasing of salt and nitrogen treatments. The results together indicated that at different saltenvironment, different amount of nitrogen supply can be used to improve the population growth of S.salsa plants, and the restoration of degraded wetland could be accelerated by nutrient supply reasonably. 
Variations in Soil Bacterial Composition and Diversity in Newly Formed Coastal Wetlands
Coastal ecosystems experience some of the most active land–ocean interactions in the world, and they are characterized by high primary productivity and biological diversity in the sediment. Given the roles of microorganisms in soil biogeochemical cycling and their multifaceted influence on soil ecosystems, it is critical to understand the variations and drivers of soil microbial communities across coastal ecosystems. Here, we studied soil bacterial community dynamics at different sites (from seawater to freshwater) in the Yellow River Delta, China. Bacterial community composition and diversity over four seasons were analyzed through 16S rRNA genes. Notably, the bacterial community near the ocean had the lowest alpha-diversity when compared with the other sites. No significant differences in bacterial communities among seasons were found, indicating that seasonal variation in temperature had little influence on bacterial community in the newly formed wetlands in the Yellow River Delta. Bacterial community structure changed substantially along the salinity gradient, revealing a clear ecological replacement along the gradual transformation gradient from freshwater to seawater environment. Redundancy analysis revealed that salinity was the main driver of variations in bacterial community structure and explained 17.5% of the variability. Our study provides a better understanding of spatiotemporally determined bacterial community dynamics in coastal ecosystems
Hydrogen Sulfide Maintains Mesenchymal Stem Cell Function and Bone Homeostasis via Regulation of Ca2+ Channel Sulfhydration
Gaseous signaling molecules such as hydrogen sulfide (H2S) are produced endogenously and mediate effects through diverse mechanisms. H2S is one such gasotrasmitter which regulates multiple signaling pathways in mammalian cells, and abnormal H2S metabolism has been linked to defects in bone homeostasis. Here, we demonstrate that bone marrow mesenchymal stem cells (BMMSCs) produce H2S to regulate their self-renewal and osteogenic differentiation, and H2S deficiency results in defects in BMMSC differentiation. H2S deficiency causes aberrant intracellular Ca2+ influx, due to reduced sulfhydration of cysteine residues on multiple Ca2+ TRP channels. This decreased Ca2+ flux downregulates PKC/Erk-mediated Wnt/β-catenin signaling which controls osteogenic differentiation of BMMSCs. Consistently, H2S-deficient mice display an osteoporotic phenotype, which can be rescued by small molecules which release H2S. These results demonstrate H2S regulates BMMSCs, and restoring H2S levels via non-toxic donors may provide treatments for diseases such as osteoporosis which can arise from H2S deficiencies
Responses of Seed Germination, Seedling Growth, and Seed Yield Traits to Seed Pretreatment in Maize (Zea mays L.)
A series of seed priming experiments were conducted to test the effects of different pretreatment methods to seed germination, seedling growth, and seed yield traits inmaize (Zeamays L.). Results indicated that the seeds primed by gibberellins (GA), NaCl, and polyethylene glycol (PEG) reagents showed a higher imbibitions rate compared to those primed with water. The final germination percentage and germination rate varied with different reagents significantly (P < 0.05). The recommended prime reagents were GA at 10 mg/L, NaCl at 50 mM, and PEG at 15% on account of germination experiment. 15% PEG priming reagent increased shoot and root biomass of maize seedling. The shoot biomass of seedlings after presoaking the seeds with NaCl reagent was significantly higher than the seedlings without priming treatment. No significant differences of plant height, leaf number, and hundred-grain weight were observed between control group and priming treatments. Presoaking with water, NaCl (50 mM), or PEG (15%) significantly increased the hundred-grain weight of maize. Therefore, seed pretreatment is proved to be an effective technique to improve the germination performance, seedling growth, and seed yield of maize. However, when compared with the two methods, if immediate sowing is possible, presoaking is recommended to harvest better benefits compared to priming method
Transcriptomics-based analysis of genes related to lead stress and their expression in the roots of Pogonatherum crinitum
Revealing plants’ tolerance and transport genes to heavy metal stress play an important role in exploring the potential of phytoremediation. Taking the heavy metal lead (Pb) hyperaccumulator plant Pogonatherum crinitum (Thunb.) Kunth as the research object, a hydroponic simulation stress experiment was set up to determine the physiological indicators such as antioxidant enzymes and non-enzymatic antioxidants in the roots of P. crinitum under different Pb concentrations (0, 300, 500, 1000, 2000 mg·L-1). RNA-Seq was performed, the Unigenes obtained by transcriptome sequencing were enriched and annotated by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, and the differential expression genes (DEGs) of root were screened and verified by quantitative real-time polymerase chain reaction (qRT-PCR). The results are as follows: with the increase of Pb concentration, superoxide dismutase (SOD), catalase (CAT), and ascorbic acid (AsA) content increased. Peroxidase (POD), malondialdehyde (MDA), and ascorbic acid–glutathione (AsA-GSH) cycles showed low promotion with high inhibition. A total of 38.21 Gb of bases were obtained by transcriptome sequencing, and the base quality of each sample reached Q20 and Q30, accounting for 90%, making the sequencing results reliable. Combined with transcriptome sequencing, functional annotation, and qRT-PCR validation results, 17 root Pb-tolerant genes of P. crinitum were screened out, which were related to antioxidation, transportation, and transcription functions. Moreover, qRT-PCR verification results under different Pb stress concentrations were consistent with the transcriptome sequencing results and changes in physiological indicators. In brief, the root of P. crinitum can adapt to the Pb stress environment by up-regulating the expression of related genes to regulate the physiological characteristics
Cell division cycle 42 effector protein 4 inhibits prostate cancer progression by suppressing ERK signaling pathway
Prostate cancer (PCa) is the most common malignancy among men worldwide. The cell division cycle 42 effector protein 4 (CDC42EP4) functions downstream of CDC42, yet its role and molecular mechanisms in PCa remain unexplored. This study aimed to elucidate the role of CDC42EP4 in the progression of PCa and its underlying mechanisms. Bioinformatical analysis indicated that CDC42EP4 expression was significantly lower in PCa tissue compared to normal prostate tissue. Cellular phenotyping analysis suggested that CDC42EP4 markedly inhibited the proliferation, migration, and invasion of PCa cells. Xenograft tumor assays further demonstrated that CDC42EP4 suppressed the growth of PCa cells in vivo. Mechanistically, the study established that CDC42EP4 inhibited the ERK pathway in PCa cells. Additionally, the ERK pathway inhibitor PD0325901 was employed, revealing that PD0325901 significantly nullified the effects of CDC42EP4 on PCa cell proliferation, migration, and invasion. Collectively, our findings demonstrate that CDC42EP4 acts as a critical tumor suppressor gene, inhibiting PCa cell proliferation, migration, and invasion through the ERK pathway, thereby presenting potential targets for PCa therapy
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