Uncovering the mechanisms of how corn steep liquor and microbial communities minimize cadmium translocation in Chinese cabbage.

Corn steep liquor-assisted microbial remediation has been proposed as a promising strategy to remediate cadmium (Cd)-contaminated soil. In this study, we determined Bacillus subtilis (K2) with a high cadmium (Cd) accumulation ability and Cd resistance. However, studies on this strategy used in the Cd uptake of Chinese cabbage are lacking, and the effect of the combined incorporation of corn steep liquor and K2 on the functions and microbial interactions of soil microbiomes is unclear. Here, we study the Cd uptake and transportation in Chinese cabbage by the combination of K2 and corn steep liquor (K2 + C7) in a Cd-contaminated soil and corresponding microbial regulation mechanisms. Results showed that compared to inoculant K2 treatment alone, a reduction of Cd concentration in the shoots by 14.4% and the dry weight biomass of the shoots and the roots in Chinese cabbage increased by 21.6% and 30.8%, respectively, under K2 + C7 treatment. Meanwhile, hydrogen peroxide (H2O2) and malondialdehyde (MDA) levels were decreased by enhancing POD and SOD activity, thereby reversing Cd-induced oxidative damage. Importantly, inoculation of K2 would decrease the diversity of the microbial community while enhancing the abundance of dominant species. These findings provide a promising strategy for reducing the Cd accumulation in Chinese cabbage and recovering soil ecological functions.

Amino acid application inhibits root-to-shoot cadmium translocation in Chinese cabbage by modulating pectin methyl-esterification.

The exogenous application of amino acids (AAs) generally alleviates cadmium (Cd) toxicity in plants by altering their subcellular distribution. However, the physiological mechanisms underlying AA-mediated cell wall (CW) sequestration of Cd in Chinese cabbage remain unclear. Using two genotypes of Chinses cabbage, Jingcui 60 (Cd-tolerant) and 16-7 (Cd-sensitive), we characterized the root structure, subcellular distribution of Cd, CW component, and related gene expression under the Cd stress. Cysteine (Cys) supplementation led to a reduction in the Cd concentration in the shoots of Jingcui 60 and 16-7 by 65.09 % and 64.03 %, respectively. Addition of Cys alleviated leaf chlorosis in both cultivars by increasing Cd chelation in the root CW and reducing its distribution in the cytoplasm and organelles. We further demonstrated that Cys supplementation mediated the downregulation of PMEI1 expression and improving the activity of pectin methyl-esterase (PME) by 17.98 % and 25.52 % in both cultivars, respectively, compared to the Cd treatment, resulting in an approximate 12.00 %-14.70 % increase in Cd retention in pectin. In contrast, threonine (Thr) application did not significantly alter Cd distribution in the shoots of either cultivar. Taken together, our results suggest that Cys application reduces Cd root-to-shoot translocation by increasing Cd sequestration in the root CW through the downregulation of pectin methyl-esterification.

Identification of lethal species in amanita section Phalloideae based on nucleotide signature and specific TaqMan-MGB probe and primer.

Amanita section Phalloideae consists of lethal toxic mushroom species, causing many fatal poisoning incidents worldwide. Molecular techniques of nucleotide signatures and single nucleotide polymorphism (SNP) detection could be used to develop a specific method for identifying lethal section (sect.) Phalloideae species. A comparison of 38 sequenced and 228 validated sequences from sect. Phalloideae species showed a 17-base pair nucleotide signature and an SNP site between the lethal and non-lethal species. A specific minor groove binder probe was designed based on them. The results indicated that this method exhibited excellent specificity for the lethal subgroup, good detection in samples subjected to simulated gastric digestion (60 min boiling and 120 min digestion), and a 10 pg./µL detection limit. This method enables accurate detection of target species in samples under complex conditions and can provide evidence for poisoning incidents caused by lethal sect. Phalloideae species to assist in targeted treatment strategies.

[The secreted level of REIC protein in gastric carcinoma and its role of proliferation inhibition].

AIM: To detect secretory REIC content in serum from the patients with gastric carcinoma and cell culture medium of gastric carcinoma cell lines, and determine the effects of recombinant REIC on proliferation of gastric carcinoma cells. METHODS: ELISA was employed to determine REIC content in serum and supernatant, and WST-8 to detect the proliferation of gastric carcinoma cells. RESULTS: The secretion level of REIC was obviously decreased in serum form gastric carcinoma, compared with healthy individuals (P<0.05) and inversely correlated with the tumor size of gastric carcinomas (P<0.05). The REIC content was lower in supernatant from gastric carcinoma cells than that in epithelial cells (P<0.05). After the transfection of REIC-expressing plasmid, the concentration of REIC was increased in supernatant from AGS (P<0.05). The proliferation of AGS and BGC-823 could be inhibited by recombinant REIC (P<0.05). CONCLUSION: REIC expression of secretion type decreased in gastric carcinoma cells, and inhibited the proliferation of gastric carcinoma cells. REIC protein might be employed as a good marker or target for the early diagnosis, biological and gene therapy of gastric carcinoma.