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Ceramic ball (CB) and cast iron ball (CIB) media were used in the grinding of chalcopyrite and pyrite (1:1) to investigate the influence of grinding media on flotation separation. The selectivity indexe values were 2.65 (CB) and 1.58 (CIB) under the optimal conditions. In the CB system, the concentrations of Cu2+, SO42−, dissolved oxygen, and pH in the slurry were slightly higher. The root-mean-square roughness (Rq) values of the CB and CIB systems ground products were 9.02 nm and 74.80 nm, respectively. Moreover, a large amount of FeOOH was formed on the surface of the CIB ground products owing to the electrochemical interaction between the minerals and the media. Density functional theory (DFT) calculations indicated that FeOOH was adsorbed preferentially on the surfaces of chalcopyrite and pyrite, thus severely hindering the adsorption of butyl xanthate. Therefore, the CB medium is beneficial for enhancing the flotation performance of chalcopyrite and pyrite.

In plants, the accumulation of carotenoids can maintain the balance of the photosystem and improve crop nutritional quality. Therefore, the molecular mechanisms underlying carotenoid synthesis and accumulation should be further explored. In this study, carotenoid accumulation differed significantly among parental Brassica rapa. Genetic analysis was carried out using the golden inner leaf ‘1900264′ line and the light−yellow inner leaf ‘1900262′ line, showing that the golden inner leaf phenotype was controlled by a single dominant gene. Using bulked−segregant analysis sequencing, BraA09g007080.3C encoding the ORANGE protein was selected as a candidate gene. Sequence alignment revealed that a 4.67 kb long terminal repeat insertion in the third exon of the BrGOLDEN resulted in three alternatively spliced transcripts. The spatiotemporal expression results indicated that BrGOLDEN might regulate the expression levels of carotenoid−synthesis−related genes. After transforming BrGOLDEN into Arabidopsis thaliana, the seed−derived callus showed that BrGOLDENIns and BrGOLDENDel lines presented a yellow color and the BrGOLDENLdel line presented a transparent phenotype. In addition, using the yeast two−hybrid assay, BrGOLDENIns, BrGOLDENLdel, and Brgoldenwt exhibited strong interactions with BrPSY1, but BrGOLDENDel did not interact with BrPSY1 in the split−ubiquitin membrane system. In the secondary and 3D structure analysis, BrGOLDENDel was shown to have lost the PNFPSFIPFLPPL sequences at the 125 amino acid position, which resulted in the α−helices of BrGOLDENDel being disrupted, restricting the formation of the 3D structure and affecting the functions of the protein. These findings may provide new insights into the regulation of carotenoid synthesis in B. rapa.

By constructing an F

Serpentine, a typically magnesium phyllosilicate gangue mineral, is often associated with chalcopyrite. In the process of flotation, serpentine is easy to get into the concentrate together with use...

Background The discovery of male sterile materials is of great significance for the development of plant fertility research. Wucai (Brassica campestris L. ssp. chinensis var. rosularis Tsen) is a variety of non-heading Chinese cabbage. There are few studies on the male sterility of wucai, and the mechanism of male sterility is not clear. In this study, the male sterile mutant MS7–2 and the wild-type fertile plant MF7–2 were studied. Results Phenotypic characteristics and cytological analysis showed that MS7–2 abortion occurred at the tetrad period. The content of related sugars in the flower buds of MS7–2 was significantly lower than that of MF7–2, and a large amount of reactive oxygen species (ROS) was accumulated. Through transcriptome sequencing of MS7–2 and MF7–2 flower buds at three different developmental stages (a–c), 2865, 3847, and 4981 differentially expressed genes were identified in MS7–2 at the flower bud development stage, stage c, and stage e, respectively, compared with MF7–2. Many of these genes were enriched in carbohydrate metabolism, phenylpropanoid metabolism, and oxidative phosphorylation, and most of them were down-regulated in MS7–2. The down-regulation of genes involved in carbohydrate and secondary metabolite synthesis as well as the accumulation of ROS in MS7–2 led to pollen abortion in MS7–2. Conclusions This study helps elucidate the mechanism of anther abortion in wucai, providing a basis for further research on the molecular regulatory mechanisms of male sterility and the screening and cloning of key genes in wucai.

Chinese cabbage, which is a cold season crop, can still be damaged at an overly low temperature. It is crucial to study the mechanism of the resistance to low temperature of Chinese cabbage. In this study, the Chinese cabbage ‘XBJ’ was used as the material, and nine different low temperatures and control samples were treated. Using RNA-seq and lignin content determination, we analyzed 27 samples, and the stained sections of them were observed. A total of 8845 genes were screened for the WGCNA analysis, yielding 17 modules. The GO and KEGG analyses of the modules was highly associated with a low-temperature treatment. The pathways such as ‘starch and sucrose metabolism’ and ‘plant hormone signal transduction’ were enriched in modules related to low temperature. Interestingly, L-15DAT-associated MEcoral2 was found to have 14 genes related to the ‘lignin biosynthetic process’ in the GO annotation. The combination of the determination of the lignin content and the treatment of the stained sections showed that the lignin content of the low-temperatures samples were indeed higher than that of the control. We further explored the expression changes of the lignin synthesis pathway and various genes and found that low temperature affects the expression changes of most genes in the lignin synthesis pathway, leading to the speculation that the lignin changes at low temperature are a defense mechanism against low temperatures. The 29 BrCOMT gene sequence derived from the RNA-seq was non-conserved, and eight BrCOMT genes were differentially expressed. This study provides a new insight into how lignin is affected by low temperature.

Selecting a suitable depressant that strongly depresses the pyrite flotation but has little effect on the floatability of chalcopyrite is of great significance for selectively separate chalcopyrite from pyrite. In this study, galactomannan (GM) was used to replace traditional depressants for depression of pyrite. The depression performance and adsorption mechanism of it on the pyrite surface were investigated by micro-flotation tests, zeta potential measurements, Fourier transform infrared spectroscopy (FTIR) measurements, and X-ray photoelectron spectroscopy (XPS) analyses. The results showed that, compared with guar gum, polyacrylamide (PAM), dextrin, carboxymethylcellulose (CMC), sodium hexametaphosphate (SHMP), GM had the optimum depression effect on pyrite, but had a negligible effect on chalcopyrite. A satisfactory separation of chalcopyrite and pyrite was achieved at weakly alkaline condition (pH 8), at which the flotation recovery of chalcopyrite was 86.11% and that of pyrite was only 13.85%. The results of surface analyses confirmed that GM could be selectively chemisorbed on pyrite surface through the Fe sites and impede the further adsorption of sodium butyl xanthate (SBX). The use of GM as a depressant, therefore, enabled the effective separation of chalcopyrite from pyrite.

Xanthate is widely used as a beneficiation reagent in mineral processing and plays an important role in subsequent wastewater disposal. Considering that kaolinite (Kaol) is a common gangue mineral in mining, understanding its interaction with xanthate is necessary. Herein, batch experiments involving Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), molecular dynamics (MD) simulation, and density function theory (DFT) are conducted to investigate the interactions between xanthate and Kaol surfaces. Results show that xanthate adsorption onto the Kaol surfaces fits well with the pseudo-first-order (PFO) and Langmuir models. The FTIR and XPS analyses suggest that xanthate interacts with Kaol surfaces through noncovalent interaction, and the MD simulations indicate that the xanthate molecule adsorbs onto the Kaol surfaces in a single layer. Moreover, the DFT results reveal that xanthate is more likely to be adsorbed onto the Kaol (0 0 1) surface than the (00ī) surface. Therefore, the presence of xanthate can influence the interaction between Kaol and the flocculant (i.e., polyacrylamide) during wastewater treatment because xanthate can occupy some of the active sites on the Kaol surface.

Soybean is a major crop species providing valuable feedstock for food, feed and biofuel. In recent years, considerable progress has been made in developing genomic resources for soybean, including on-going efforts to sequence the genome. These efforts have identified a large number of soybean genes, most with unknown function. Therefore, a major research priority is determining the function of these genes, especially those involved in agronomic performance and seed traits. One means to study gene function is through mutagenesis and the study of the resulting phenotypes. Transposon-tagging has been used successfully in both model and crop plants to support studies of gene function. In this report, we describe efforts to generate a transposon-based mutant collection of soybean. The Ds transposon system was used to create activation-tagging, gene and enhancer trap elements. Currently, the repository houses approximately 900 soybean events, with flanking sequence data derived from 200 of these events. Analysis of the insertions revealed approximately 70% disrupted known genes, with the majority matching sequences derived from either Glycine max or Medicago truncatula sequences. Among the mutants generated, one resulted in male-sterility and was shown to disrupt the strictosidine synthase gene. This example clearly demonstrates that it is possible to disrupt soybean gene function by insertional mutagenesis and to derive useful mutants by this approach in spite of the tetraploid nature of the soybean genome.

The dopaminergic and sympathetic systems interact to regulate blood pressure. Our previous studies show the regulation of dopamine receptor on α 1 -adrenergic receptor function. Due to the regulation of renalase on sympathetic tone, we hypothesize that dopamine receptor, especially D 1 -like receptor, might regulate renalase in kidney. The effect of D 1 -like receptor on renalase expression and function was checked in immortalized renal proximal tubule (RPT) cells from Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHRs). It resulted that D 1 -like receptor agonist, fenoldopam (10 -7 -10 -5 M), increased renalase protein expression and function in WKY RPT cells, in contrast, decreased it in SHR cells. These effects were blocked by D 1 -like receptor antagonist SCH 23390 (10 -6 M). Fenoldopam increased renalase mRNA level in WKY RPT cells, but not in SHR cells. Fenoldopam increased the degradation of renalase protein in both WKY and SHR cells. However, the degradation degree was higher in SHR cells than in WKY cells. The regulation of D 1 -like receptor on renalase was mainly via D 5 receptor, because inhibition of D 5 , not D 1 receptor, by antisense blocked inhibitory effect of D 1 -like receptor on renalase in WKY cells. Moreover, inhibition of PKC, by PKC inhibitor 19-31, blocked the effect of fenoldopam on renalase expression; stimulation of PKC, by PKC agonist (PMA), inhibited renalase expression and function, indicating that PKC is involved in the process. Consistent with the in-vitro study, renalase expression was lower in kidney from SHRs than in WKY rats. It indicated that D 1 -like receptor, via D 5 receptor, regulates renalase expression and function in RPT cells, aberrant regulation of D 5 receptor on renalase might be involved in the pathogenesis of hypertension.