Testing plastomes and nuclear ribosomal DNA sequences as the next-generation DNA barcodes for species identification and phylogenetic analysis in Acer.

BACKGROUND: Acer is a taxonomically intractable and speciose genus that contains over 150 species. It is challenging to distinguish Acer species only by morphological method due to their abundant variations. Plastome and nuclear ribosomal DNA (nrDNA) sequences are recommended as powerful next-generation DNA barcodes for species discrimination. However, their efficacies were still poorly studied. The current study will evaluate the application of plastome and nrDNA in species identification and perform phylogenetic analyses for Acer. RESULT: Based on a collection of 83 individuals representing 55 species (c. 55% of Chinese species) from 13 sections, our barcoding analyses demonstrated that plastomes exhibited the highest (90.47%) species discriminatory power among all plastid DNA markers, such as the standard plastid barcodes matK + rbcL + trnH-psbA (61.90%) and ycf1 (76.19%). And the nrDNA (80.95%) revealed higher species resolution than ITS (71.43%). Acer plastomes show abundant interspecific variations, however, species identification failure may be due to the incomplete lineage sorting (ILS) and chloroplast capture resulting from hybridization. We found that the usage of nrDNA contributed to identifying those species that were unidentified by plastomes, implying its capability to some extent to mitigate the impact of hybridization and ILS on species discrimination. However, combining plastome and nrDNA is not recommended given the cytonuclear conflict caused by potential hybridization. Our phylogenetic analysis covering 19 sections (95% sections of Acer) and 128 species (over 80% species of this genus) revealed pervasive inter- and intra-section cytonuclear discordances, hinting that hybridization has played an important role in the evolution of Acer. CONCLUSION: Plastomes and nrDNA can significantly improve the species resolution in Acer. Our phylogenetic analysis uncovered the scope and depth of cytonuclear conflict in Acer, providing important insights into its evolution.

Impact of the climatic changes in the Pliocene-Pleistocene transition on Irano-Turanian species. The radiation of genus Jurinea (Compositae).

The Irano-Turanian region is one of the world's richest floristic regions and the centre of diversity for numerous xerophytic plant lineages. However, we still have limited knowledge on the timing of evolution and biogeographic history of its flora, and potential drivers of diversification remain underexplored. To fill this knowledge gap, we focus on the Eurasian genus Jurinea (ca. 200 species), one of the largest plant radiations that diversified in the region. We applied a macroevolutionary integrative approach to explicitly test diversification hypotheses and investigate the relative roles of geography vs. ecology and niche conservatism vs. niche lability in speciation processes. To do so, we gathered a sample comprising 77% of total genus richness and obtained data about (1) its phylogenetic history, recovering 502 nuclear loci sequences; (2) growth forms; (3) ecological niche, compiling data of 21 variables for more than 2500 occurrences; and (4) paleoclimatic conditions, to estimate climatic stability. Our results revealed that climate was a key factor in the evolutionary dynamics of Jurinea. The main diversification and biogeographic events that occurred during past climate changes, which led to colder and drier conditions, are the following: (1) the origin of the genus (10.7 Ma); (2) long-distance dispersals from the Iranian Plateau to adjacent regions (∼7-4 Ma); and (3) the diversification shift during Pliocene-Pleistocene Transition (ca. 3 Ma), when net diversification rate almost doubled. Our results supported the pre-adaptation hypothesis, i.e., the evolutionary success of Jurinea was linked to the retention of the ancestral niche adapted to aridity. Interestingly, the paleoclimatic analyses revealed that in the Iranian Plateau long-term climatic stability favoured old-lineage persistence, resulting in current high species richness of semi-arid and cold adapted clades; whereas moderate climate oscillations stimulated allopatric diversification in the lineages distributed in the Circumboreal region. In contrast, growth form lability and high niche disparity among closely related species in the Central Asian clade suggest adaptive radiation to mountain habitats. In sum, the radiation of Jurinea is the result of both adaptive and non-adaptive processes influenced by climatic, orogenic and ecological factors.

Phylogeny, origin, and dispersal of Dubyaea (Asteraceae) based on Hyb-Seq data.

Dubyaea DC. is a small genus of Asteraceae that is almost exclusively endemic to the Pan-Himalayan region. Within Dubyaea, phylogenetic relationships remain poorly understood. Here, our well-supported phylogeny based on Hyb-Seq data shows that all samples of Dubyaea in this study belong to a monophyletic group, which is sister to the clade of Soroseris, Syncalathium, and Nabalus. Dubyaea (s. str.) can be divided into three major clades, which are supported by flower color as well as morphological features of the stems and basal leaves. Based on our phylogenetic results, we performed biogeographic analyses and inferred that Dubyaea arose in the late Miocene in Hengduan Mountains and its eastern areas. Following its evolutionary origin, Dubyaea underwent diversification in situ as well as spread to the Himalayas.

Phylogeny, origin and dispersal of Saussurea (Asteraceae) based on chloroplast genome data.

Saussurea is one of the largest genera of the tribe Cardueae of Asteraceae, comprising about 460 species from the Northern Hemisphere with most species distributed in QTPss and adjacent areas. Here, we established a well-supported phylogenetic framework for Saussurea based on whole chloroplast genomes of 136 taxa plus 16 additional taxa of Cardueae using Bayesian inference and Maximum Likelihood. Our phylogenetic results are inconsistent with previous subgeneric classifications of Saussurea. We nearly completely delimited subgen. Eriocoryne, and found that subgen. Theodorea, subgen. Saussurea section Laguranthera and Rosulascentes are closely related to each other. Based on our phylogenetic results, we performed biogeographic analyses and inferred that the genus Saussurea arose during early-middle Miocene within the Hengduan Mountains. We expect that landscape heterogeneity within the QTPss and adjacent areas, such as the Hengduan Mountains, played an important role in the evolution of Saussurea. Following its evolutionary origin, the genus underwent rapid diversification in situs and dispersed northwards in several migrational patterns. Both continuous uplift of the QTPss and adjacent areas as well as global cooling since mid-Miocene probably led to geographic expansion and diffusion of Saussurea, with the latter, in particular, resulting in the northward dispersal.

Interface Effects on Magnetic Flux Pinning in La0.7Sr0.3MnO3/YBa 2Cu3O7-x Bilayers.

The magnetic pinning properties of a ferromagnet/superconductor hybrid structure consisting of a La0.7Sr0.3MnO3(LSMO) layer with various thicknesses on top of a fixed thickness YBa2Cu3O7-x (YBCO) layer are investigated in this article. The existence of a weakly magnetic layer was identified at the interface between YBCO and LSMO by a ferromagnetic resonance (FMR) study. Magnetic moment and anisotropy of the interfacial layer were probed using the angular-dependent FMR study. This layer gives rise to an additional flux pinning contribution to the bulk magnetic pinning from the LSMO layer. Our study provides insight into the complex interface physics in the LSMO/YBCO bilayer system, promoting a new pathway for the development of novel flux pinning-related functionality.

Correlation of grain orientations and the thickness of gradient MoS2 films.

In this study, we synthesized gradient MoS2 films with a home-made suspended mask and characterized them by transmission electron microscopy (TEM) and Raman spectroscopy. The advantage of using gradient films is to simultaneously produce numerous samples under the same growth condition but with different thicknesses. The cross-sectional TEM images and their Fourier transform spectra revealed the thickness dependency of the grain orientations for synthetic MoS2 films. Combining the TEM results and the data of Raman A1g and E1 2g peaks, we found the correlation between the grain orientation and the A1g/E1 2g peak area ratio. We demonstrated the potential of using the non-polarized Raman Spectroscopy to characterize the grain structures of synthetic MoS2 films.

2-Methyl-3-nitro-benzyl cyanide.

The title compound, C(9)H(8)N(2)O, was prepared from o-xylene by nitration, oxidation, hydrolysis, reduction, chlorination and cyanation. There are two mol-ecules in the asymmetric unit with a dihedral angle of 20.15 (7)° between their aromatic rings.

2-Amino-6-nitro-1H-benzoimidazol-3-ium chloride.

In the cation of the title compound, C(7)H(7)N(4)O(2) (+)·Cl(-), the benzimidazole ring system is planar with a maximum deviation of -0.019 (3) Å. In the crystal structure, C-H⋯Cl, N-H⋯Cl, and N-H⋯Cl inter-actions link the mol-ecules into a two-dimensional network. π-π contacts between benzimidazole rings [centroid-centroid distances = 3.928 (1) and 3.587 (1) Å] may further stabilize the structure.

(2-Methyl-3-nitro-phen-yl)methanol.

The asymmetric unit of the title compound, C(8)H(9)NO(3), contains two crystallographically independent mol-ecules, whose aromatic rings are oriented at a dihedral angle of 83.29 (3)°. In the crystal structure, inter-molecular O-H⋯O hydrogen bonds link the mol-ecules into chains.

[Studies on the lowering blood sugar substances from agrimony].

OBJECTIVE: To isolate and identify the chemical constituents from the active section lowering blood sugar of agrimony. METHODS: The compounds were separated by repeated silica gel, Sephadex LH-20 and HPLC chromatographies. The structures of compounds isolated were identified by analysis of their spectral data and chemical properties. RESULTS: Nine compounds were isolated from the active section with lowering blood sugar of agrimony and their structures were identified as apigenin-7-O-3-D-glucopyranoside (1), catechin (2), quercetin (3), rutin (4), kaempferol-3-O-alpha-L-rhamnoside (5), Kampferol-3-O-beta-D-glucopyranoside (6), lutcolin-7-O-beta-D-glucopyranosidc (7), 19alpha, 24-dihydroxy ursolic acid (8), 3,3'-di-O-mcthyl ellagic acid4-O-beta-D-glucopyranoside (9). CONCLUSION: Compounds 1, 7, 8, 9 are isolated from thia plant for the first time.

Novel oxazabicycles as a new class of photochromic colorants.

A new photochromic colorant with an oxazabicyclic moiety has been synthesized by an efficient method. It turns pale red upon UV irradiation and undergoes reverse reaction while being heated. This work may open an exciting new avenue for future development of the photochromic dyes with novel molecular structures.

4-Bromo-2,6-dimethyl-anilinium bromide monohydrate.

In the title compound, C(8)H(11)BrN(+)·Br(-)·H(2)O, a network of N-H⋯O, N-H⋯Br and O-H⋯Br hydrogen bonds helps to consolidate the crystal packing.

Five novel prenylated xanthones from Resina Garciniae.

Fourteen prenylated xanthone derivatives were isolated from gamboge, the dry latex of Garcinia hanburyi, and their structures were elucidated by a detailed spectroscopic analysis. Five of them, isogambogenic acid (1), desoxymorellinin (2), 10-methoxygambogenic acid (3), 10-methoxygambogic acid (4) and 10-ethoxy gambogic acid (5), are new compounds. All of them showed potent cytotoxicity against HL-60, SMMC-7721 and BGC-83 cells.

Enzyme inhibition potency enhancement by active site metal chelating and hydrogen bonding induced conformation-restricted cyclopropanecarbonyl derivatives.

Two cyclopropanecarbonyl derivatives were independently found to be 15 and 14 times more potent than the corresponding isopropylcarbonyl analogues as inhibitors of 4-hydroxyphenylpyruvate dioxygenase and dihydroorotate dehydrogenase, respectively. A thorough examination of the co-crystal structures of available enzyme inhibitor complexes and the conformation of X-ray crystal structures of several synthesized cyclopropanecarbonyl derivatives revealed that this enhancement by one order of magnitude of inhibition potency exhibited by cyclopropanecarbonyl derivatives in both enzymes is probably caused by respective metal chelating and hydrogen bonding interactions at the ligand-receptor binding site. These specific interactions subsequently cause the cyclopropyl group of the molecules to adopt a fixed bisected conformation, which is unavailable for isopropylcarbonyl derivatives.