Mutation of the rice AN1-type zinc-finger protein gene ASL4 causes chloroplast development defects and seedling lethality.

Plant zinc-finger proteins play a crucial role in biosynthesis and plant development. However, it is not known whether certain zinc-finger proteins play a role in rice chloroplast development. In this study, a novel rice zinc-finger protein mutant asl4 (albino seedling lethality4), which exhibits an albino lethal phenotype at the seedling stage, was used. Chlorophyll fluorescence analysis and TEM were used to investigate features of the asl4 mutant. The genetic behaviour and function of ASL4 gene were then analysed thorough map-based cloning, transgenic complement and subcellular localization. The albino lethal phenotype was caused by a single nucleotide (G*) deletion mutation on the exon of the ASL4 (LOC_Os09g21710) gene. The ASL4 gene encoded a novel zinc-finger protein containing two ZnF-AN1 domains, which was localized to the nucleocytoplasm. The ASL4 transcripts were highly expressed in all leaves but relatively less in other tissues, suggesting its tissue-specific expression. The transcript levels of associated genes for Chl biosynthesis, photosynthesis and chloroplast development were severely suppressed in asl4 mutants. In conclusion, the absence of ASL4 function caused a defect in chloroplast development and seedling lethality. This is the first published report on the importance of the ZnF-AN1 type zinc-finger protein gene in chloroplast development in rice.

Performance characterization and application of composite adsorbent LiCl@ACFF for moisture harvesting.

Freshwater scarcity is a global threat to modern era of human society. Sorption-based atmospheric water harvesting (AWH) is prospective to provide fresh water for remote water-stressed areas lacking in water and electricity. Adsorbent material plays a vital role in such AWH systems. Here, we report a solid adsorbent synthesized by impregnating hygroscopic salt lithium chloride (LiCl) into solidified activated carbon fiber felt (ACFF modified by silica sol). Composite samples immersed with different mass concentrations of silica sol are prepared and characterized for dynamic water uptake, equilibrium water uptake, textural and thermal properties. AS5Li30 (ACFF + 5 wt% silica gel + 30 wt% LiCl) exhibits an efficient water uptake of 2.1 g/g at 25 °C and 70% relative humidity (RH). The material further demonstrates a heat storage capacity of 5456 kJ/kg. Its low regeneration temperature (< 80 °C) and good cycle stability make it feasible to be used in practical water production applications, driven by solar energy and other low-grade energy. Estimation results show that water harvesting unit can produce 1.41 gH2O/gAS5Li30 under 25 °C and 75% RH.

DGCR8 promotes the metastasis in triple-negative breast cancer by epigenetically regulating TGF-ß.

OBJECTIVE: Breast cancer (BC) is one of the most ordinary fatal cancers. Recent studies have identified the vital role of genes in the development and progression of Tri-negative breast cancer (TNBC). In this research, DGCR8 was studied to identify how it functioned in the metastasis of TNBC. PATIENTS AND METHODS: DGCR8 expression of tissues was detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR) in 50 TNBC patients. Wound healing assay and transwell assay were used to observe the changes in the biological behaviors of TNBC cells through knockdown or overexpression of DGCR8. In addition, qRT-PCR and Western blot assay were performed to discover the potential target protein of DGCR8 in TNBC. RESULTS: DGCR8 expression level in TNBC samples was higher than that of adjacent ones. Besides, the migration ability and invasion ability of TNBC cells were inhibited after DGCR8 was silenced, while they were promoted after DGCR8 was overexpressed. In addition, TGF-ß was downregulated after silencing of DGCR8 in TNBC cells, while TGF-ß was upregulated after overexpression of DGCR8 in TNBC cells. Furthermore, TGF-ß was upregulated in TNBC tissues, which was positively associated with DGCR8. CONCLUSIONS: Our study uncovers a new oncogene in TNBC and suggests that DGCR8 can enhance TNBC cell migration and invasion via targeting TGF-ß, which provides a novel therapeutic target for TNBC patients.

[Advances in osteoradionecrosis of nasopharynx after radiotherapy for nasopharyngeal carcinoma].

Radiation therapy is the first choice for the treatment of nasopharyngeal carcinoma. However, it is inevitable that nasopharyngeal mucosa and tissue will be damaged after radiotherapy of nasopharyngeal carcinoma, which will cause corresponding complications. Nasopharyngeal osteonecrosis is a serious complication. Up to now, there are few reports about nasopharyngeal osteonecrosis, and the underlaying pathological mechanism remains unclear. The potential theories include radiotherapy damage, infection and trauma, but also the " three H" principle of hypoxic hypocellular hypovascular tissue, as well as the theory of radio induced fibrosis. It is controversial about the treatment of nasopharyngeal osteonecrosis. It takes comprehensive treatment, including local treatment, systemic treatment, surgical treatment and other treatments. Among them, local treatment as nasopharyngeal debridement usually is first choice. We reviewed the pathological mechanism and treatment methods of nasopharyngeal osteonecrosis, in order to provide a reference for better prevention and treatment of it.

Functional roles of valine 37 and glycine 38 in the mobile loop of porcine cytosolic aspartate aminotransferase.

The functional roles of Val37 and Gly38 in porcine cytosolic aspartate aminotransferase have been studied in the site-directed mutants V37A, G38A, and G38S where the size and hydrophobic character of these residues has been altered. Previous x-ray studies have shown that Val37 and Gly38, which are part of a flexible loop, interact directly with bound substrate. From x-ray and solution experiments we find that the V37A, G38A, and G38S mutations do not cause significant perturbations to the unliganded enzyme. Replacing Val37 with a less bulky alanine residue does not affect the maximal catalytic rate (kcat), but it does increase significantly the Michaelis constants for substrates in the overall transamination reaction between aspartate and 2-oxoglutarate. On the other hand, replacing Gly38 with alanine or serine results in striking decreases in kcat to 5 and 0.6%, respectively, of the value observed for the wild-type enzyme, as well as in considerable increases in Km values. Consequently, the catalytic competence, kcat/Km, decreases by 3 orders of magnitude for G38A and by 4 orders of magnitude for G38S. Single turnover reactions of G38A and G38S with four individual substrates (aspartate, glutamate, oxalacetate, and 2-oxoglutarate) are characterized by kinetic parameters that are largely consistent with those of the overall reaction. In addition, the mutations at position 38 impair more seriously the catalytic competence of the enzyme toward C5-substrates than toward C4-substrates. We conclude that Gly38 is probably required for proper function of the enzyme because it permits a high level of flexibility for the 36-39 peptide, which in turn allows the essential substrate-induced movement of the small domain.