Background Aedes albopictus is an indigenous primary vector for dengue and Zika viruses in China. Compared with its insecticide resistance, biology and vector competence, little is known about its genetic variation, which corresponds to environmental variations. Thus, the present study examines how Ae. albopictus varies among different climatic regions in China and deciphers its potential dispersal patterns. Methods The genetic variation and population structure of 17 Ae. albopictus populations collected from three climatic regions of China were investigated with 11 microsatellite loci and the mitochondrial coxI gene. Results Of 44 isolated microsatellite markers, 11 pairs were chosen for genotyping analysis and had an average PIC value of 0.713, representing high polymorphism. The number of alleles was high in each population, with the ne value increasing from the temperate region (3.876) to the tropical region (4.144). Twenty-five coxI haplotypes were detected, and the highest diversity was observed in the tropical region. The mean Ho value (ca. 0.557) of all the regions was significantly lower than the mean He value (ca. 0.684), with nearly all populations significantly departing from HWE and displaying significant population expansion (p value < 0.05). Two genetically isolated groups and three haplotype clades were evaluated via STRUCTURE and haplotype phylogenetic analyses, and the tropical populations were significantly isolated from those in the other regions. Most genetic variation in Ae. albopictus was detected within populations and individuals at 31.40 and 63.04%, respectively, via the AMOVA test, and a relatively significant positive correlation was observed among only the temperate populations via IBD analysis (R2 = 0.6614, p = 0.048). Recent dispersions were observed among different Ae. albopictus populations, and four major migration trends with high gene flow (Nm > 0.4) were reconstructed between the tropical region and the other two regions. Environmental factors, especially temperature and rainfall, may be the leading causes of genetic diversity in different climatic regions. Conclusions Continuous dispersion contributes to the genetic communication of Ae. albopictus populations across different climatic regions, and environmental factors, especially temperature and rainfall, may be the leading causes of genetic variation. Graphical abstract

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Solvothermal reactions of 2,3,5,6-tetraIJ2-pyridyl)pyrazine (tppz) and sodium azide with different cadmium salts including CdCl 2 •2.5H 2 O, Cd(NO 3 ) 2 and Cd(CH 3 COO) 2 •2H 2 O at 80 °C produce three new coordination, respectively. Single-crystal X-ray diffraction analysis reveals that the anions of the Cd(II) salts all participate in coordination in compounds 1-3. Compound 1 features an infinite one-dimensional (1D) chain with loops-and-rods topology, compound 2 exhibits a 1D ladder-like chain, while compound 3 possesses a 2D honeycomb-like network structure with (6,3) topology. The low-dimensional structures of compounds 1-3 are further stabilized by diverse supramolecular interactions such as hydrogen bonds and π⋯π stacking. Interestingly, when the temperature is increased to 100 °C, similar reactions of tppz and sodium azide ligands with CdCl 2 •2.5H 2 O, Cd(NO 3 ) 2 and Cd(CH 3 COO) 2 •2H 2 O lead to three other novel 3D Cd(II) coordination polymers formulated as [Cd 3 (N 3 ) 6 (tppz)] n (4), {[Cd 2 (N 3 ) 2 (tppz)(NO 3 ) 2 ]•MeOH} n (5) and [Cd 4 (N 3 ) 6 (tppz)(CH 3 COO) 2 ] n (6), respectively. The anions of the Cd(II) salts again take part in coordination in compounds 5 and 6 but disappear in the final structure of 4. Compound 4 displays a rare sxd-type 3D framework with the Schläfli symbol of (3 3 •4 6 •5 5 •6) if each V-shaped trinuclear [Cd 3 (μ 1,1 -N 3 ) 4 ] secondary building unit (SBU) is regarded as a 6-connected node. In compound 5, both the Cd1 and Cd2 atoms serve as 3-connected nodes to construct an uncommon binodal (3,3)-connected 3D framework with (6•10 2 )(6 2 •10) topology. Compound 6 contains another type of V-shaped trinuclear [Cd 3 (μ 1,1 -N 3 ) 2 (μ 3 -CH 3 COO)] SBU, which acts as a 7-connected node to fabricate a unique uninodal 7-connected 3D framework with a completely new topology of (3 6 •4 2 •5 10 •6 3 ). The present results reveal that both anions and temperature play essential roles in the structural and topological diversity of such six new Cd(II) coordination polymers.Moreover, the IR spectra, thermogravimetric analysis curves, and solid-state luminescence properties of all the compounds have been also investigated. Compared with the free tppz ligand, compounds 1-6 exhibit superior luminescence properties with largely enhanced emission, indicating that they may be good candidates for optical materials.

Baeckea frutescens is an aromatic shrub used as ornamentals and as food flavor spices in the southern part of P. R. China. Two novel C-methylated biflavonoids named baeckeins J (1) and K (2) were isolated from the roots of B. frutescens, which possessed the unique carbon skeleton conjugated of a flavonol and one isoflavanonol molecule via the linkages of C(2)-C(8*) and C(3)-O-C(7*). The structures of compounds 1 and 2 were elucidated by analysis of 1D-and 2D-NMR, and HR-ESI-MS spectral data, and the absolute configuration for chiral C-atoms C(2) and C(3) were assigned by CD spectrometry combined with quantum chemical calculations. In the bioassay, baeckeins J and K exhibited strong cytoprotective effects on H 2 O 2induced oxidative cell death in PC12 cells.

Background:Aedes albopictus is an indigenous primary vector for Dengue and Zika viruses in China. Compared with its insecticide resistance, biology, and vector competence, little is known about its genetic variation, which corresponds to environmental variations. Thus, the present study examines how Ae. albopictus varies among different climatic regions in China and deciphers its potential dispersal patterns.Methods:The genetic variation and population structure of 17 Ae. albopictus populations collected from three climatic regions of China were investigated with 11 microsatellite loci and the mitochondrial coxI gene.Results:Of 44 isolated microsatellite markers, 11 pairs were chosen for genotyping analysis and had an average PIC value of 0.713, representing high polymorphism. The number of alleles was high in each population, with the ne value increasing from the temperate region (3.876) to the tropical region (4.144). Twenty-five coxI haplotypes were detected, and the highest diversity was observed in the tropical region. The mean Ho value (ca. 0.557) of all the regions was significantly lower than the mean He value (ca. 0.684), with nearly all populations significantly departing from HWE and displaying significant population expansion (p-value < 0.05). Two genetically isolated groups and three haplotype clades were evaluated via STRUCTURE and haplotype phylogenetic analyses, and the tropical populations were significantly isolated from those in the other regions. Most genetic variation in Ae. albopictus was detected within populations and individuals at 31.40% and 63.04%, respectively, via the AMOVA test, and a relatively significant positive correlation was observed among only the temperate populations via IBD analysis (R2 = 0.6614, p = 0.048). Recent dispersions were observed among different Ae. albopictus populations, and four major migration trends with high gene flow (Nm>0.4) were reconstructed between the tropical region and the other two regions. Environmental factors, especially temperature and rainfall, may be the leading causes of genetic diversity in different climatic regions.Conclusions:Continuous dispersion contributes to the genetic communication of Ae. albopictus populations across different climatic regions, and environmental factors, especially temperature and rainfall, may be the leading causes of genetic variation.