Interactions of chiral molecules with an (r)-n-(3,5-dinitrobenzoyl) phenylglycine HPLC stationary phase

Forty different chiral molecules were studied by liquid chromatography with a Pirkle-type, (R)-N-(3,5-dinitrobenzoyl) phenylglycine (DNBPG), chiral stationary phase column. The dramatic effect of a small molecular change on chiral recognition was demonstrated using DL-amino acid derivatives. The inductive effect on chiral recognition was also studied using trifluoro-, trichloro-, dichloro-, monochloroacetyl, and acetyl derivatives of four different chiral amines. The study of the enantiomer separation of 11 different crown ethers of 2,2′-binaphthyldiyl showed that the rigidity of the chiral center can be an additional parameter in chiral recognition for the DNBPG phase but not for a β-cyclodextrin bonded chiral phase. It is apparent from this study that steric effects, inductive effects, and molecular rigidity play important roles in chiral recognition with DNBPG chiral stationary phases.     

A Study on the Morphology of Foliar Trichomes of Evergreen Oaks (Quercus) in China and Its Implication in Taxonomy

Most of the evergreen oaks (Quercus L.) are endemic to China and distributed in a large moutainous area of southwestern China at an altitude of 2600-4000m. The delimitation of sections and species in the group has not been satisfactorily solved. The foliar trichomes are very an important character in identifying species of oaks. As a result of observation on 17 species and 2 varieties of evergreen oaks in China under scanning electron microscope, ten types of foliar trichomes are recognized: Simpleuniseriate, Simple-branched, Bulbous, Rosulate, Solitary, Stipitate-fasciculate, Fasciculate, Multiradiate, Stellate and Fused-stellate. The first four types fall into glandular trichomes and the last six non-glandular trichomes. The taxa examined have a combination of various types of the trichomes. All the evergreen oaks have non-glandular trichomes on their foliar epidermis, but glandular trichomes occur solely in certain taxa. These two types of foliar trichomes are obviously different in structure and function, which represent different adular trichomes and the last six non-glandular en oaks are divided into two groups: the glandular group and the non-glandular group according to the types of foliar trichomes and it is reasonable to divide the evergreen oaks into two sections: Sect. Suber (Reichenb.) Spach and Sect. Englerianae (A. Camus) Hsu et Jen. Foliar trichomes of the evergreen oaks show a continuity in density from species predominately with glandular trichomes at a high altitude to species solely with non-glandular trichomes at a low elevation. The characters of branching of foliar trichomes, especially the number of branches, can imply to some extent the evolutionary position of a given evergreen species. Considering the types, density and branches of foliar trichomes combined the evolutionary relationships among the evergreen oaks in China are proposed. Q. gilliana is the startpoint, from where evolution took place in two directions: glandular and non-glandular. In the glandular direction envolved are Q. aquifolioides, Q. longispica and Q. guyavaefolia. Q. pannosa is a species with the most types and highest number of glandular trichomes. In non-glandular line aligned are Q. spinosa, Q. senescens, Q. senescens var. muliensis, Q. monimotricha with the reduction of glandular trichomes and increase of non-glandular trichomes. After Q. tungmaiensis no glandular trichomes appear and it solely depends on non-glandular trichomes to protect itself. Q. granchetii is the climax in the non-glandular line with the highest density and number of branches of foliar trichomes. And then some species, such as Q. engleriana, Q. phillyraeoides, have few or no trichomes. Q. dolicholepis, Q. baronii and Q. baronii var. capitata show the close re-lationships because they share fused-stellate trichomes.     

Genetic differentiation of Pseudoregma bambucicola population based on mtDNA COII gene

mtDNA COII gene sequences were identified and analyzed using different types of software, namely, MEGA5.0, DNAMAN, and DnaSP5.0 in four Chinese provinces, namely, Sichuan, Zhejiang, Guizhou and Shanghai. Analysis of molecular genetic variation and its genetic structure and differentiation, combined with NJ tree, MP tree analysis and analysis of molecular variance (AMOVA), at Fst = 0.0582 conclude that the genetic differentiation is low, gene flow is Nm = 8.0911, and gene exchange is sufficient. However, for the geographic populations of Pseudoregma bambucicola in the four provinces, their gene exchange is relatively weak at Nm = 0.8284, whereas the genetic differentiation is high at Fst = 0.3764. Based on the data, total nucleotide diversity between the populations is 0.00158 ± 0.00021. The results showed that the total population of Tajima’s D and Fu’s Fs results are D = ?0.885 and Fs = 0.226, respectively. The experimental numerical results showed that this total population is not significant (P > 0.10), indicating that nine different geographic populations are short-term. No expansion occurred in the internal population. This study provided a theoretical and practical basis for the comprehensive prevention and control of P. bambucicola.     

Testing the responses of four wheat crop models to heat stress at anthesis and grain filling

Higher temperatures caused by future climate change will bring more frequent heat stress events and pose an increasing risk to global wheat production. Crop models have been widely used to simulate future crop productivity but are rarely tested with observed heat stress experimental datasets. Four wheat models (DSSAT‐CERES‐Wheat, DSSAT‐Nwheat, APSIM‐Wheat, and WheatGrow) were evaluated with 4 years of environment‐controlled phytotron experimental datasets with two wheat cultivars under heat stress at anthesis and grain filling stages. Heat stress at anthesis reduced observed grain numbers per unit area and individual grain size, while heat stress during grain filling mainly decreased the size of the individual grains. The observed impact of heat stress on grain filling duration, total aboveground biomass, grain yield, and grain protein concentration (GPC) varied depending on cultivar and accumulated heat stress. For every unit increase of heat degree days (HDD, degree days over 30 °C), grain filling duration was reduced by 0.30–0.60%, total aboveground biomass was reduced by 0.37–0.43%, and grain yield was reduced by 1.0–1.6%, but GPC was increased by 0.50% for cv Yangmai16 and 0.80% for cv Xumai30. The tested crop simulation models could reproduce some of the observed reductions in grain filling duration, final total aboveground biomass, and grain yield, as well as the observed increase in GPC due to heat stress. Most of the crop models tended to reproduce heat stress impacts better during grain filling than at anthesis. Some of the tested models require improvements in the response to heat stress during grain filling, but all models need improvements in simulating heat stress effects on grain set during anthesis. The observed significant genetic variability in the response of wheat to heat stress needs to be considered through cultivar parameters in future simulation studies.     

IL-33-Dependent Endothelial Activation Contributes to Apoptosis and Renal Injury in Orientia tsutsugamushi-Infected Mice

Endothelial cells (EC) are the main target for Orientia tsutsugamushi infection and EC dysfunction is a hallmark of severe scrub typhus in patients. However, the molecular basis of EC dysfunction and its impact on infection outcome are poorly understood. We found that C57BL/6 mice that received a lethal dose of O. tsutsugamushi Karp strain had a significant increase in the expression of IL-33 and its receptor ST2L in the kidneys and liver, but a rapid reduction of IL-33 in the lungs. We also found exacerbated EC stress and activation in the kidneys of infected mice, as evidenced by elevated angiopoietin (Ang) 2/Ang1 ratio, increased endothelin 1 (ET-1) and endothelial nitric oxide synthase (eNOS) expression. Such responses were significantly attenuated in the IL-33^-/- mice. Importantly, IL-33^-/- mice also had markedly attenuated disease due to reduced EC stress and cellular apoptosis. To confirm the biological role of IL-33, we challenged wild-type (WT) mice with a sub-lethal dose of O. tsutsugamushi and gave mice recombinant IL-33 (rIL-33) every 2 days for 10 days. Exogenous IL-33 significantly increased disease severity and lethality, which correlated with increased EC stress and activation, increased CXCL1 and CXCL2 chemokines, but decreased anti-apoptotic gene BCL-2 in the kidneys. To further examine the role of EC stress, we infected human umbilical vein endothelial cells (HUVEC) in vitro. We found an infection dose-dependent increase in the expression of IL-33, ST2L soluble ST2 (sST2), and the Ang2/Ang1 ratio at 24 and 48 hours post-infection. This study indicates a pathogenic role of alarmin IL-33 in a murine model of scrub typhus and highlights infection-triggered EC damage and IL-33-mediated pathological changes during the course of Orientia infection.     

A transgenic plant cell‐suspension system for expression of epitopes on chimeric Bamboo mosaic virus particles

We describe a novel strategy to produce vaccine antigens using a plant cell‐suspension culture system in lieu of the conventional bacterial or animal cell‐culture systems. We generated transgenic cell‐suspension cultures from Nicotiana benthamiana leaves carrying wild‐type or chimeric Bamboo mosaic virus (BaMV) expression constructs encoding the viral protein 1 (VP1) epitope of foot‐and‐mouth disease virus (FMDV). Antigens accumulated to high levels in BdT38 and BdT19 transgenic cell lines co‐expressing silencing suppressor protein P38 or P19. BaMV chimeric virus particles (CVPs) were subsequently purified from the respective cell lines (1.5 and 2.1 mg CVPs/20 g fresh weight of suspended biomass, respectively), and the resulting CVPs displayed VP1 epitope on the surfaces. Guinea pigs vaccinated with purified CVPs produced humoral antibodies. This study represents an important advance in the large‐scale production of immunopeptide vaccines in a cost‐effective manner using a plant cell‐suspension culture system.     

元谋古猿下颌臼齿三维立体特征

采用欧氏距离矩阵分析（EDMA）方法对72枚元谋古猿及作为对比样本的10枚禄丰古猿、现生大猿类和人类下颌臼齿齿冠13个测量标志点三维测量数据的统计分析显示：元谋古猿在下颌臼齿齿冠三维形态测量特征上与禄丰古猿最为接近。与现生大猿类及人类相比,元谋古猿和禄丰古猿均与人类之间呈现出非常显著的差异,而与猿类较为接近。它们两者及生大猿类均与人类之间具有许多共同的差异表现特点。元谋古猿在下颌臼齿三维测量特征方面与三种现生大猿类各自之间的差别表现相似。其中,元谋古猿与猩猩之间的牙齿形态特征上似乎更为接近。但目前对这些特征相似差异的含义尚难以确定。