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Comprehensive Summary: Chemical investigation of Fritillaria verticillata Willd. led to the isolation of eight novel isosteroidal alkaloids (1—4, 6, 9—11) and four known alkaloids (5, 7—8, 12), including three unprecedented cis‐fused D/E (13α, 17α) cevanine alkaloids (1—3), one rarely cis‐fused E/F (22α) cevanine alkaloid (6), and one uncommon 5β‐jervine‐type isosteroidal alkaloid featuring a cis‐fused A/B ring moiety (11). In order to establish the structures of 1, the calculated NMR with DP4+ evaluation was applied from the plausible structure candidates. The characteristic proton signals for distinguishing D/E conjunction of cevanine alkaloids were summarized. In addition, some proton and carbon signals α to nitrogen in 6 and 7 are unobservable due to the 14N nuclear quadrupolar relaxation, based on the NMR experiments in different solvents, calculated NMR method and X‐ray technology, their structures were determined. The NMR characteristics of cevanine alkaloids to distinguish orientation of long‐pair on nitrogen atom with β‐hydroxyl at C‐20 were also concluded. The anti‐inflammatory effects of compounds 1 and 4 were evaluated in LPS‐activated RAW 264.7 macrophages. Compound 4 decreased LPS‐induced releases of IL‐1β and IL‐17α in RAW264.7 cells in a dose‐dependent manner. Further mechanistic study revealed that 4 suppressed the phosphorylation of IκBα and p65 subunit to regulate the NF‐κB signaling pathway. [ABSTRACT FROM AUTHOR]

Cerasus serrulata (Rosaceae) is an important flowering cherry resource which is valuable for developing new cultivars of flowering cherries. It is broadly distributed and possesses abundant variations. In this study, phylogeographic analysis was conducted to reveal the evolutionary history to better understand the genetic diversity and genetic structure of C. serrulata so as to provide more accurate molecular insights into better conservation and utilization of the germplasm resources. A total of 327 individuals from 18 wild populations were collected. Three chloroplast DNA (cpDNA) fragments (matK, trnD‐E, and trnS‐G) and the nuclear internal transcribed spacer (ITS) were utilized. The results showed a high genetic diversity at both species level and population level of C. serrulata. High genetic differentiation and the existence of the phylogeographic structure were detected. No significant expansion events were discovered. Two geographic lineages were inferred. One was confined to the Qinling Mountains and the Taihang Mountains. The other was from the Wuling Mountains to the Jiangnan Hilly Regions and then went northeast to the coast of Asia. In addition, some taxonomic treatments of the C. serrulata complex are discussed and reconsidered. Conservation and utilization strategies of wild C. serrulata germplasm resources were recommended. [ABSTRACT FROM AUTHOR]

Impending climate warming is expected to influence plant growth and distribution, and the distribution range limit of tree species is extremely sensitive to climate change. However, synchronous comparisons of responses of different tree species with overlapping ecological niches to climate at their distribution range limit in the same region have received little attention. In the present study, we assessed the discrepancy in radial growth responses of two dominant oak species to climate at their distribution range limit (southern range limit for Quercus mongolica, northern range limit for Quercus variabilis) in Beijing, China. Furthermore, growth-climate relationships were examined using linear mixed-effects models, and growth trends up to the year 2100 were forecast based on future climate scenarios (RCP2.6 and RCP8.5). Our results indicated that there were no significant differences in the growth response to climate between Q. variabilis at its northern limit and Q. mongolica at its southern limit, and the growth of the two tree species was positively correlated with the minimum temperature and negatively correlated with the climatic moisture deficit of autumn. However, the growth response to climate variables varied at different sites. Additionally, the model forecast showed an increase in radial growth of Q. variabilis at its northern limit and Q. mongolica at its southern limit up to the end of the present century. [ABSTRACT FROM AUTHOR]

Enterotoxigenic Escherichia coli (ETEC), a major global cause of diarrhea, initiates the pathogenic process via fimbriae-mediated attachment to the small intestinal epithelium. A common prototypic ETEC fimbria, colonization factor antigen I (CFA/I), consists of a tip-localized minor adhesive subunit CfaE and the stalk-forming major subunit CfaB, both of which are necessary for fimbrial assembly. To elucidate the structure of CFA/I at atomic resolution, three recombinant proteins were generated consisting of fusions of the minor and major subunits (CfaEB) and of two (CfaBB) and three (CfaBBB) repeats of the major subunit. Crystals of CfaEB diffracted X-rays to 2.1 Å resolution and displayed the symmetry of space group P21. CfaBB exhibited a crystal diffraction limit of 2.3 Å resolution and had the symmetry of space group P21212. CfaBBB crystallized in the monoclinic space group C2 and diffracted X-rays to 2.3 Å resolution. These structures were determined using the molecular-replacement method. [ABSTRACT FROM AUTHOR]

Abstract Rotavirus gastroenteritis is an important pediatric disease in China. In a survey of rotavirus infection at two sentinel hospitals in China (Beijing Friendship Hospital and Changchun Children’s Hospital), 296 cases were detected. A total of 283 (95.6%) cases of rotavirus infection occurred in children under 5 years of age. Serotype G1 (62%) was most prevalent followed by G2 (28.5%), G3 (5%) and G4 (2%). Mixed infections (n=8, 3%) were rare, and 16 isolates (5.5%) remained non-typeable. A consistent epidemic occurred during the winter. Rotavirus was responsible for about 61.8% of diarrhea-related hospitalizations in children under 5 years of age, with a mean hospital stay of 5.6 days (1.0–21 days). The estimated rate of rotavirus-attributed hospitalizations was 16/1000 children under 5 years of age per year. Rotavirus-related death is rare in Changchun and Beijing. The present findings suggest that a rotavirus vaccine for the prevention of severe disease and a reduction of treatment costs would be of significant benefit to China. [ABSTRACT FROM AUTHOR]

Enterotoxigenic Escherichia coli (ETEC) represents a formidable food and waterborne diarrheal disease threat of global importance. The first step in ETEC pathogenesis is bacterial attachment to small-intestine epithelial cells via adhesive fimbriae, many of which are genetically related to the prototype colonization factor antigen I (CFA/I). The minor fimbrial subunit CfaE is required for initiation of CFA/I fimbrial assembly and mediates bacterial attachment to host cell-surface receptors. A donor-strand complemented variant of CfaE (dscCfaE) was expressed with a hexahistidine tag, purified to homogeneity and crystallized using the hanging-drop vapor-diffusion method. X-ray diffraction data sets were collected to 2.4 A resolution for both native and derivatized crystals and showed the symmetry of space group P6(2)22, with unit-cell parameters a = b = 142.9, c = 231.9 A. Initial phases were derived from the SIRAS approach and electron density showed two molecules in the crystallographic asymmetric unit. Sequence assignments were aided by anomalous signals from the selenium of an SeMet-derivatized crystal and from S atoms of a native crystal.