229 research outputs found
Methyl 3-hydroxy-4-(3-methylbut-2-enyloxy)benzoate
The title compound, C13H16O4, was isolated from culture extracts of the endophytic fungus Cephalosporium sp. The ester and ether substituents are twisted only slightly out of the benzene ring plane, making dihedral angles of 2.16 (2) and 3.63 (5)°, respectively. The non-H atoms of all three substituents are almost coplanar with the benzene ring, with an r.m.s. deviation of 0.0284 Å from the mean plane through all non-H atoms in the structure. A weak intramolecular O—H⋯O hydrogen bond contributes to this conformation. In the crystal structure, molecules are linked into a one-dimensional chain by intermolecular O—H⋯O hydrogen bonds. Weak non-classical C—H⋯π contacts are also observed in the structure
6,8-Dihydroxy-3-methylisocoumarin
The title compound, C10H8O4, was isolated from the fermentation culture of the endophytic fungus Cephalosporium sp. In the crystal structure, molecules are connected into a one-dimensional chain along [101] by intermolecular O—H⋯O hydrogen bonds involving the hydroxyl and carbonyl functionalities. The chains are linked by non-classical C—H⋯O interactions, forming extended two-dimensional layers approximately parallel to (11)
1,3-Bis(chloromethyl)-2-methyl-5-nitrobenzene
The title compound, C9H9Cl2NO2, is a natural product isolated from the endophytic fungus No. B77 of the mangrove tree from the South China Sea coast. In the crystal structure, the molecules lie on twofold axes and form offset stacks through face-to-face π–π interactions. Adjacent molecules in each stack are related by a centre of inversion and have an interplanar separation of 3.53 (1) Å, with a centroid–centroid distance of 3.76 (1) Å. Between stacks, there are C—H⋯O interactions to the nitro groups and Cl⋯Cl contacts of 3.462 (1) Å
3-Hydroxymethyl-6,8-dimethoxy-2H-chromen-2-one
The asymmetric unit of the title compound, C12H12O5, contains four independent molecules. In the crystal structure, intermolecular O—H⋯O hydrogen bonds link the molecules into one-dimensional infinite chains. They are arranged in a nearly parallel fashion along the b axis and stabilized by π–π interactions [3.443 (2) Å]
Organization of plastid genomes in the freshwater red algal order Batrachospermales (Rhodophyta)
Little is known about genome organization in members of the order Batrachospermales, and the infra-ordinal relationship remains unresolved. Plastid (cp) genomes of seven members of the freshwater red algal order Batrachospermales were sequenced, with the following aims: (i) to describe the characteristics of cp genomes and compare these with other red algal groups; (ii) to infer the phylogenetic relationships among these members to better understand the infra-ordinal classification. Cp genomes of Batrachospermales are large, with several cases of gene loss, they are gene-dense (high gene content for the genome size and short intergenic regions) and have highly conserved gene order. Phylogenetic analyses based on concatenated nucleotide genome data roughly supports the current taxonomic system for the order. Comparative analyses confirm data for members of the class Florideophyceae that cp genomes in Batrachospermales is highly conserved, with little variation in gene composition. However, relevant new features were revealed in our study: genome sizes in members of Batrachospermales are close to the lowest values reported for Florideophyceae; differences in cp genome size within the order are large in comparison with other orders (Ceramiales, Gelidiales, Gracilariales, Hildenbrandiales, and Nemaliales); and members of Batrachospermales have the lowest number of protein-coding genes among the Florideophyceae. In terms of gene loss, apcF, which encodes the allophycocyanin beta subunit, is absent in all sequenced taxa of Batrachospermales. We reinforce that the interordinal relationships between the freshwater orders Batrachospermales and Thoreales within the Nemaliophycidae is not well resolved due to limited taxon sampling
Observation of Majorana fermions with spin selective Andreev reflection in the vortex of topological superconductor
Majorana fermion (MF) whose antiparticle is itself has been predicted in
condensed matter systems. Signatures of the MFs have been reported as zero
energy modes in various systems. More definitive evidences are highly desired
to verify the existence of the MF. Very recently, theory has predicted MFs to
induce spin selective Andreev reflection (SSAR), a novel magnetic property
which can be used to detect the MFs. Here we report the first observation of
the SSAR from MFs inside vortices in Bi2Te3/NbSe2 hetero-structure, in which
topological superconductivity was previously established. By using
spin-polarized scanning tunneling microscopy/spectroscopy (STM/STS), we show
that the zero-bias peak of the tunneling differential conductance at the vortex
center is substantially higher when the tip polarization and the external
magnetic field are parallel than anti-parallel to each other. Such strong spin
dependence of the tunneling is absent away from the vortex center, or in a
conventional superconductor. The observed spin dependent tunneling effect is a
direct evidence for the SSAR from MFs, fully consistent with theoretical
analyses. Our work provides definitive evidences of MFs and will stimulate the
MFs research on their novel physical properties, hence a step towards their
statistics and application in quantum computing.Comment: 4 figures 15 page
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A Refined Study of FCRL Genes from a Genome-Wide Association Study for Graves’ Disease
To pinpoint the exact location of the etiological variant/s present at 1q21.1 harboring FCRL1-5 and CD5L genes, we carried out a refined association study in the entire FCRL region in 1,536 patients with Graves’ disease (GD) and 1,516 sex-matched controls by imputation analysis, logistic regression, and cis-eQTL analysis. Among 516 SNPs with P<0.05 in the initial GWAS scan, the strongest signals associated with GD and correlated to FCRL3 expression were located at a cluster of SNPs including rs7528684 and rs3761959. And the allele-specific effects for rs3761959 and rs7528684 on FCRL3 expression level revealed that the risk alleles A of rs3761959 and C of rs7528684 were correlated with the elevated expression level of FCRL3 whether in PBMCs or its subsets, especially in B cells and T subsets. Next, the combined analysis with 5,300 GD cases and 4,916 control individuals confirmed FCRL3 was a susceptibility gene of GD in Chinese Han populations, and rs3761959 and rs7528684 met the genome-wide association significance level ( = 2.27× and 7.11×, respectively). Moreover, the haplotypes with the risk allele A of rs3761959 and risk allele C of rs7528684 were associated with GD risk. Finally, our epigenetic analysis suggested the disease-associated C allele of rs7528684 increased affinity for NF-KB transcription factor. Above data indicated that FCRL3 gene and its proxy SNP rs7528684 may be involved in the pathogenesis of GD by excessive inhibiting B cell receptor signaling and the impairment of suppressing function of Tregs
Seaweed diversification driven by Taiwan’s emergence and the Kuroshio Current: insights from the cryptic diversity and phylogeography of Dichotomaria (Galaxauraceae, Rhodophyta)
Ocean currents play a role in both facilitating and impeding connectivity of marine organisms’ populations, serving as key drivers and potential barriers. The emergence of Taiwan around five million years ago (Mya) impacted the Kuroshio Current which later shaped the distribution of marine organisms. In this study, we examined how the Kuroshio Current influenced the distribution and population divergence of the marine red alga Dichotomaria elegans (Galaxauraceae, Nemaliales). Through phylogenetic analysis, species delimitation, and morphological comparison of Taiwanese species, we determined its phylogenetic position relative to other species within the D. marginata complex of the genus Dichotomaria. We uncovered the hidden cryptic diversity within the D. marginata complex in Taiwan and proposed the new combinations D. elegans and D. latifolia based on Galaxaura elegans and G. latifolia. Genetic analysis based on three loci (mitochondrial cox2-3 and cox1, and plastid rbcL) from 32 locations across the Philippines, Taiwan, and Japan revealed three allopatric lineages within D. elegans. The first lineage is restricted to the northern Philippines and southern Taiwan, while the second has a broader latitudinal range along the Kuroshio Current. The third lineage is found in southeast Luzon, Philippines, close to the bifurcation of the North Equatorial Current, near the start of the Kuroshio Current. The divergence of the first two lineages during the mid-Pliocene (~3.7 Mya) coincided with the emergence of Taiwan, with the current dynamics accentuating their separation. The Kuroshio Current exhibited a dual impact on the biogeography of D. elegans: promoting the dispersal of the second lineage towards higher latitudes and preventing the first lineage from moving northward. Principal component analysis showed that habitat conditions and morphologies differed between the two D. elegans lineages. This study provides insights into the cryptic diversity of Dichotomaria in Taiwan, as well as the genetic divergence, biogeographical patterns, and ecological associations of D. elegans, highlighting the interplay of island formation and currents shaping the diversification of seaweeds in the Northwest Pacific Ocean
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