[Seed morphology and germination characteristics of Tripterygium wilfordii].

The seeds of Tripterygium wilfordii are characterized by dormancy and a long germination cycle under natural sowing conditions. In this study, we developed a method for rapid germination of T. wilfordii seeds by analyzing the size, morphology, thousand-grain weight, viability, moisture content, physicochemical properties, and seed germination rates under different germination conditions. The seeds of T. wilfordii were fine columnar with a thick and hard outer seed coat. They had the length of 6.69 mm, the width of 2.14 mm, the thickness of 1.68 mm, the thousand-grain weight of 8.99 g, the moisture content of 8.86%, the soluble sugar content of 21.3 mg·g~(-1), the starch content of 28.9 mg·g~(-1), the soluble protein content of 44.2 mg·g~(-1), and the seed viability of only 54.0%. The seeds were respectively treated with distilled water, ultrasonication, low-temperature storage, 50 ℃ water, 100 mg·L~(-1) 6-BA, 0.6% KMnO_4, 1% KNO_3, 50 mg·L~(-1) NAA, and 100 mg·L~(-1) GA_3 solution. The results showed that soaking the seeds in 100 mg·L~(-1) GA_3 solution significantly promoted the germination. Further, the seeds were soaked in 50, 100, 250, 500, and 1 000 mg·L~(-1) GA_3 solutions, which demonstrated that high concentration(500 mg·L~(-1), 1 000 mg·L~(-1)) of GA_3 solutions increased the germination rate and speed and shortened the germination cycle from more than 3 months to less than 15 days. The findings of this study are of great significance to the breeding of T. wilfordii and lay a foundation for the large-scale propagation of T. wilfordii seeds and the excavation of T. wilfordii germplasm resources.

Genotypic Heterogeneity of Orientia tsutsugamushi in Scrub Typhus Patients and Thrombocytopenia Syndrome Co-infection, Myanmar.

Serologic and molecular surveillance of serum collected from 152 suspected scrub typhus patients in Myanmar revealed Orientia tsutsugamushi of genotypic heterogeneity. In addition, potential co-infection with severe fever with thrombocytopenia syndrome virus was observed in 5 (3.3%) patients. Both scrub typhus and severe fever with thrombocytopenia syndrome are endemic in Myanmar.

Optimal Parameter Selection for Support Vector Machine Based on Artificial Bee Colony Algorithm: A Case Study of Grid-Connected PV System Power Prediction.

Predicting the output power of photovoltaic system with nonstationarity and randomness, an output power prediction model for grid-connected PV systems is proposed based on empirical mode decomposition (EMD) and support vector machine (SVM) optimized with an artificial bee colony (ABC) algorithm. First, according to the weather forecast data sets on the prediction date, the time series data of output power on a similar day with 15-minute intervals are built. Second, the time series data of the output power are decomposed into a series of components, including some intrinsic mode components IMFn and a trend component Res, at different scales using EMD. The corresponding SVM prediction model is established for each IMF component and trend component, and the SVM model parameters are optimized with the artificial bee colony algorithm. Finally, the prediction results of each model are reconstructed, and the predicted values of the output power of the grid-connected PV system can be obtained. The prediction model is tested with actual data, and the results show that the power prediction model based on the EMD and ABC-SVM has a faster calculation speed and higher prediction accuracy than do the single SVM prediction model and the EMD-SVM prediction model without optimization.

Ca2+ binding effects on the C2 domain conformation of human cytosolic phospholipase A2.

It has been reported that the cooperative binding of calcium ions indicated a local conformational change of the human cytosolic phospholipase A2 (cPLA2) C2 domain (Nalefski et al., (1997) Biochemistry 36, 12011-12018). However its structural evidence is less known (Malmberg et al., (2003) Biochemistry 42, 13227-13240). In this letter, life-time decay and fluorescence quenching techniques were employed to compare the calcium-induced conformational changes. The life-time decay parameters and fluorescence quenching constant changes were small between the apo- and holo-C2 domains when tryptophan residue was excited at 295 nm. In contrast, the quenching constant change was large, from 0.52 M(-1) for the apo-C2 to 8.8 M(-1) for the holo-C2 domain, when tyrosine residues were excited at 284 nm. Our results provide new information on amino acid side chain orientation change at calcium binding loop 3, which is necessary for Ca2+ binding regulated membrane targeting of human cytosolic phospholipase A2.

Sequential conformation changes of chinese hamster ovary dihydrofolate reductase at its active sites.

The local fluorescence probes, 2-(p-toluidino)-6-naphthalenesulfonic acid (TNS) and NADPH were employed to detect urea-induced conformation changes at each active site of dihydrofolate reductase (DHFR), respectively. The results indicate that local conformation change at DHF/TNS could be superimposed by the conformation change calculated from the enzyme activity change with a three-state model; while at NADPH site it is lagged in the first transition. This difference is further supported by the different relative changes of Michaelis constants at 0, 1 and 1.8 M urea for each substrate. Our results suggest that local conformation at DHF site is more flexible than that at NADPH site, and the urea-induced unfolding could be ascribed to a four-state transition.