Construction of a Ginseng Root-Meristem Sensor and a Sensing Kinetics Study on the Main Nitrogen Nutrients.

Severe continuous cropping obstacles exist in ginseng cultivation. In order to assess these obstacles, a "sandwich" ginseng root tissue sensor was developed for the kinetic determination of five nitrogen nutrients. The results showed that the sensing parameters of the sensor reached an ultrasensitive level (limit of detection up to 5.451 × 10-24 mol/L) for the five nitrogen nutrients, and exhibited good stability and reproducibility. In the order of two-, four-, and six-year-old ginseng plants, the sensitivity to inorganic nitrogen nutrients (sodium nitrate and urea) showed an upward trend following an initial decline (the interconnected allosteric constant Ka values acted as the parameter). The fluctuations in sensor sensitivity to organic nitrogen nutrients, specifically nucleotides (disodium inosinate and disodium guanylate), were relatively small. The sensor sensitivity of two-, four-, and six-year-old ginseng plants to sodium glutamate was 9.277 × 10-19 mol/L, 6.980 × 10-21 mol/L, and 5.451 × 10-24 mol/L, respectively. Based on the survival rate of the seedlings and mortality rate of the ginseng in each age group, a Hardy-Weinberg equilibrium analysis was carried out. The results showed that the sensing ability of the root system to sodium glutamate may be an important factor affecting its survival under continuous cropping obstacles with increasing age.

R-lipoic acid overdosing affects platelet life span via ROS mediated autophagy.

R-lipoic acid (ALA), a powerful antioxidant valuable for the treatment of diabetes and its complications, has been reported to exhibit an antiplatelet activity in vitro. The aim of this study was to investigate the effect and mechanism of ALA on platelets in vivo. Sprague-Dawley (SD) male rats were intravenously administered with low-dose ALA (20 mg/kg/d), high-dose ALA (80 mg/kg/d) and saline, respectively. Platelets count and bone marrow smear were evaluated and the expressions of markers related to apoptosis and autophagy were measured. Platelet clearance analysis was conducted out on mice. The results showed that high-dose ALA administration could significantly decrease platelet count by 43% compared with control group, whereas, megakaryocytes showed no difference in the number. Moreover, high-dose ALA administration led to significant reduction in half-life of circulating platelets, indicative of enhanced rate of platelet clearance. Interesting, high-dose ALA administration could increase the level of reactive oxygen species (ROS) in platelets and induce autophagy without affecting apoptosis. Our finding also showed that high ALA-induced autophagy in platelets was mediated by class III PtdIns3K activity, which could be reversed by 3-methyladenine (3-MA). Moreover, AKT and MAPK/ERK pathways were also observed to be involved in the regulation of autophagy in platelets. Thus, high-dose ALA could induce autophagy in platelets through modulating the activity of class III PtdIns3K, which was associated with decreased count of circulating platelets and shortened lifespan of platelets.

Isolation of mono-caffeoylquinic acids from tobacco waste using continuous resin-based pre-separation and preparative HPLC.

Three isomers of mono-caffeoylquinic acid, specifically, 3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid and 5-O-caffeoylquinic acid, were successfully isolated from a crude extract of tobacco (Nicotiana tobaccum L.) wastes using continuous resin-based pre-separation and preparative high-performance liquid chromatography (HPLC). The extract of tobacco wastes was continuously pre-separated by resin-based columns packed with D101 and XAD-4, yielding total mono-caffeoylquinic acids with a purity of 67.71% and a recovery rate of 90.06%. Variables affecting resolution and productivity of three mono-caffeoylquinic acid isomers in preparative HPLC (i.e. mobile-phase composition, pH, flow rate and loading amount) were studied. The optimum chromatographic conditions were determined to be a mobile phase consisting of 15% (v/v) methanol and aqueous acetic acid with a pH of 4.5, a flow rate of 4.0 mL/min, a loading amount of 4 mL and a detection wavelength of 360 nm. From 300 mg of loading sample, 56.3 mg of 3-O-caffeoylquinic acid, 92.8 mg of 5-O-caffeoylquinic acid and 73.1 mg of 4-O-caffeoylquinic acid were obtained in a single run, each with a purity of over 98% by HPLC. The structures of the isolated compounds were elucidated by ESI-MS, (1) H-NMR and (13) C-NMR spectral data.