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The reserves of nitrate (NO3-) mineral resources in the Turpan-Hami Basin in Xinjiang rank second after those in the Atacama Desert in Chile, South America. Considerable attention has been devoted to nitrogen (N) sources of NO3- deposits in recent years due to the increase in demand for NO3- fertilizers in agriculture and chemical industries. However, although the potassium nitrate (KNO3) deposits in the Uyunbulak salt lake in the Kumish basin, Xinjiang, China, have received increasing attention from numerous researchers in recent years, they all focused on the study of nitrate sources and agreed that the nitrate source in the Kumish basin is mainly atmospheric sedimentation. Studies on their water sources are scarce; for salt lake nitrate deposits, water supply also plays a crucial role in the genesis of the deposit. As a sensitive indicator, a boron isotope is often used to indicate water bodies from different sources. However, the presence of NO3- ions in water will interfere with the determination of boron isotopes, so the research on boron isotopes in nitrate salt lakes has been hindered. In this study, the three-step ion exchange method published by Ma et al. (2020) was used to eliminate the influence of NO3- ions in water on boron isotope determination, so as to reveal the water supply of Uyunbulak Salt Lake in Kumish basin by using boron isotopes which are more sensitive to water types. In this study, ice and snow meltwater, fissure water, groundwater, and surface water samples were collected from the Kumish basin and analyzed for the determination of boron (B) isotopic and hydrochemical compositions during the migration process of water bodies to reveal the recharge relationship between the water bodies from the northwestern margin of the basin and the study area. The obtained hydrochemical composition results showed a gradual increase in the salinity of the water body from 556 to 7372 mg/L from the northwestern to the southeastern parts of the basin, resulting in a gradual change in the hydrochemical facies type of Uyunbulak salt lake to NaCl. This finding suggested that the water body migrates from the northwestern to southeastern parts of the basin. The results of B isotope composition indicated two types of water bodies from different sources, namely, the ice and snow meltwater of the Southern part of the Tianshan Mountains and groundwater of the basin, exhibiting B isotope composition ranges of 26.66–27.26‰ and 12.75–15.19‰, respectively. These two types of water bodies are mixed at the Uzong spring (Q1). The ice and snow meltwater in the mixed water accounted for 46%, while the groundwater accounted for 54%. The mixed water continues to recharge the Uyunbulak Salt Lake in the southeastern part of the basin. [ABSTRACT FROM AUTHOR]

The Gas Hure Salt Lake (GHSL) in the northwestern Qaidam Basin, western China, is rich in boron (B) resources, but its B‐resource origin is hardly known. Hydrochemical compositions and B isotope characteristics of different waters were collected around the GHSL, including the river water, stream water, spring water, salt‐lake brine, intercrystalline brine, well water, drilling brine, and solar pond brine. The hydrochemical signatures suggest that silicates, carbonates and evaporates are the main B‐bearing rocks during the water dynamic. The reservoir estimation of B resources shows that the Kulamulekesay River (KLMR) and the Atekan River (ATKR) contribute annually 18.3 tons and 22.84 tons of B, respectively, with a total amount of 11.72 × 104 tons of B during the past 5.7 ka. In comparison with the known B reservoir (32.96 × 104 tons) in the GHSL, a significant amount of B in the GHSL was probably recharged from deep fluids and sediments around the GHSL. The B concentration and B‐enrichment degree are shaped by the evaporation process, which are highly elevated at the carnallite and bischofite stages. [ABSTRACT FROM AUTHOR]

Eukaryotic expression systems are used widely and have the advantages of protein processing, proteolytic cleavage, disulfide bond formation, and posttranslational modification in contrast to the prokaryotic expression system. In the present study, peptide gene (olive flounder beta‐defensin or hepcidin) was inserted into the vector of pPIC9K, which involved the secretion signal and promoter AOX1. The colonies with high copy numbers of the target gene for high‐level expression were selected by G418. Approximately 30 mg/L for beta‐defensin and 25 mg/L for hepcidin was obtained from the culture medium supernatant. An ammonium sulfate salting‐out method was used for purification; this one‐step purification simplified the procedures, and the purification effect was good in terms of the purity and yield. The proteins from yeast itself could be isolated easily using the ammonium sulfate salting‐out method. [ABSTRACT FROM AUTHOR]

Peptides containing multiple disulfide bonds are usually problematic when expressed in Escherichia coli. We conducted the expression of β-defensin with three disulfide bonds, hepcidin with four disulfide bonds, and DkTx with six disulfide bonds using a small leader protein mosaic expression in the periplasm of E. coli, and purified them by affinity chromatography and characterized them by mass spectroscopy. The result showed that the expression level was high. A large amount of the pure recombinant peptide was also recovered after purification with a Ni2+ affinity column. The mass results by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry ( MALDI-TOF MS) indicated that the recombinant peptides had a folding structure, with the native status of all of the cysteines participating in disulfide bond formation. Moreover, after removing the tags, the result was identical to its natural form as well. We thus provide a method for producing large amounts of soluble peptides containing multiple disulfide bonds in E. coli. [ABSTRACT FROM AUTHOR]