Embedded within the meristem of all Angiosperm roots is a population of slowly dividing cells designated the quiescent center (QC). In maize roots the QC can constitute upwards of 800-1200 cells, most of which spend an extended period of time (180-200 hours) in the G 1 phase of the cell cycle. How the QC forms and is maintained is not known. Here we report that cells of the QC are characterized by their highly oxidized status. Glutathione and ascorbic acid occur predominately in the oxidized forms in the QC. This is contrasted with the status of these redox intermediates in adjacent, rapidly dividing cells in the root meristem, in which the reduced forms of these two species are favored. Using a redox sensitive fluorescent dye we were able to visualize an overall oxidizing environment in the QC, and we also made comparisons with the adjacent, rapidly dividing cells in the root meristem. Altering the distribution of auxin and the location of the auxin maximum in the root tip activates the QC, and cells leave G1 and enter mitosis. Commencement of relatively more rapid cell division in the QC is preceded by changes in the overall redox status of the QC, which becomes less oxidizing. We discuss how the position of the auxin maximum may influence the redox status of the QC and thereby modulate the cell cycle.

The SID1 transmembrane family member 2 (sidt2) deficient mouse model was used to investigate the function of sidt2 in lysosomal membrane permeabilization and lipid metabolism of liver tissue. The mouse model was established by Cre/LoxP technology. Enzymatic methods were used to analyze the sidt2−/− mouse serum lipids, aspartate transaminase, alanine transaminase and serum bilirubin, compared with sidt2+/+ mice. Defective lipid metabolism and damaged liver functions were observed in the sidt2−/− mice. By using hematoxylin and eosin and Oil Red O staining, changes of morphology were observed in sidt2−/− mice with optical microscopy. Transmission electron microscopy was also used. Hepatic steatosis and partial liver tissue apoptosis were observed. The tissue distribution of sidt2 protein and mRNA was measured in knockout mice. The results indicated that negligible sidt2 mRNA and protein expression were observed in sidt2−/− mice, and that sidt2−/− mice had abnormal liver functions. Transmission electron microscopy revealed membrane lipid droplets in the liver cell cytoplasm, and some apoptotic body formation. These results demonstrated that absence of the lysosomal membrane protein sidt2 led to changes in lysosomal membrane permeabilization and lipid metabolism.

Anti-inflammatory component (AIC) known as an important constituent of artificial musk exhibits bioactive effects on many pharmacological models. This study describes an immunochemical assay for the quality control of artificial musk in traditional Chinese medicine using an enzyme-linked immunosorbent assay. A polyclonal antibody against AIC was produced by rabbit. The method, at an effective measuring range of 3.13-200 ng/ml of AIC, 3 ng/ml limit of detection, and no cross-reaction with natural musk, successfully detected artificial musk in many traditional Chinese prescriptions containing artificial musk. The results demonstrated that a novel and reliable assay system for detection of artificial musk was generated.

The purpose of this study was to compare the metabolic properties of maintenance hemodialysis patients treated with glucose-containing and glucose-free dialysate using metabonomics. Pre- and post-dialysis serum samples from group G (−) using glucose-free dialysate, and group G (+) using glucose-added dialysate (glucose levels were 5.5 mmol/L) were analyzed and tested with high performance liquid chromatography quadrupole time-of-flight mass spectrometry. Orthogonal signal correction–partial least squares discriminate analysis revealed a significant difference in the post-dialysis metabolic properties between samples from the G (−) and G (+) groups, and concentrations of leucine and dihydroxyprostaglandin F2α were higher in the G (+) group than in the G (−) group. However, markers of reactive lipid mobilization and amino acid release, such as bile acids, aspartate, and valine, were lower in the G (+) group than in the G (−) group. There were no significant differences in excitatory neurotransmitters aspartate and phosphorylated anandamide. Use of liquid chromatography-tandem mass spectrometry metabonomics indicated that using glucose-added dialysate was superior to glucose-free dialysate in the protection of the central nervous system of maintenance hemodialysis patients, but had potential risks in stimulating oxidative stress.