Effects of habitat fragmentation on genetic diversity and gene flow among the Homidia socia (Collembola: Entomobryidae) populations in the Thousand Island Lake

In the present study, partial sequences of the mitochondrial cytochrome oxidase subunit I (COI) gene of 22 island populations of the springtail Homidia socia in the Thousand Island Lake were sequenced. Across all sequences, 37 haplotypes were identified for the 510‐bp mitochondrial (mt) DNA COI gene. Haplotype 2 was the most common, and was distributed in the most of the 22 island populations. Haplotype diversity ranged from 0.065 to 0.733, and the total genetic diversity was 0.56216. The genetic characteristics of the 22 island populations were analyzed using the fixation index and gene flow, with values of 0.00043–0.94900 and 0.02703–703.72540, respectively. Comparison between (island area and isolations) with population genetic diversity revealed that there were no significant correlations between them, except for a significant correlation between the number of haplotypes and island area. Mantel tests showed that there was no significant correlation between geographic distance and genetic distance among various groups. All the results indicated that there were no obvious relationships between island characteristics and the genetic diversity of the springtails. We consider that the low dispersal capacity of springtails and the island patches surrounded by water in the Thousand Island Lake are the major factors affecting the genetic diversity of H. socia.     

Phylogenomics using low‐depth whole genome sequencing: A case study with the olive tribe

Species trees have traditionally been inferred from a few selected markers, and genome‐wide investigations remain largely restricted to model organisms or small groups of species for which sampling of fresh material is available, leaving out most of the existing and historical species diversity. The genomes of an increasing number of species, including specimens extracted from natural history collections, are being sequenced at low depth. While these data sets are widely used to analyse organelle genomes, the nuclear fraction is generally ignored. Here we evaluate different reference‐based methods to infer phylogenies of large taxonomic groups from such data sets. Using the example of the Oleeae tribe, a worldwide‐distributed group, we build phylogenies based on single nucleotide polymorphisms (SNPs) obtained using two reference genomes (the olive and ash trees). The inferred phylogenies are overall congruent, yet present differences that might reflect the effect of distance to the reference on the amount of missing data. To limit this issue, genome complexity was reduced by using pairs of orthologous coding sequences as the reference, thus allowing us to combine SNPs obtained using two distinct references. Concatenated and coalescence trees based on these combined SNPs suggest events of incomplete lineage sorting and/or hybridization during the diversification of this large phylogenetic group. Our results show that genome‐wide phylogenetic trees can be inferred from low‐depth sequence data sets for eukaryote groups with complex genomes, and histories of reticulate evolution. This opens new avenues for large‐scale phylogenomics and biogeographical analyses covering both the extant and the historical diversity stored in museum collections.     

Dysregulated expression of ACTN4 contributes to endothelial cell injury via the activation of the p38-MAPK/p53 apoptosis pathway in preeclampsia

Journal of Physiology and Biochemistry - Preeclampsia (PE) is a hypertensive disease associated with increased endothelial cell dysfunction caused by systemic oxidative stress. Alpha-actinin-4...     

Microbial community responses reduce soil carbon loss in Tibetan alpine grasslands under short‐term warming

Changes in labile carbon (LC) pools and microbial communities are the primary factors controlling soil heterotrophic respiration (R_h) in warming experiments. Warming is expected to initially increase R_h but studies show this increase may not be continuous or sustained. Specifically, LC and soil microbiome have been shown to contribute to the effect of extended warming on R_h. However, their relative contribution is unclear and this gap in knowledge causes considerable uncertainty in the prediction of carbon cycle feedbacks to climate change. In this study, we used a two‐step incubation approach to reveal the relative contribution of LC limitation and soil microbial community responses in attenuating the effect that extended warming has on R_h. Soil samples from three Tibetan ecosystems—an alpine meadow (AM), alpine steppe (AS), and desert steppe (DS)—were exposed to a temperature gradient of 5–25°C. After an initial incubation period, soils were processed in one of two methods: (a) soils were sterilized then inoculated with parent soil microbes to assess the LC limitation effects, while controlling for microbial community responses; or (b) soil microbes from the incubations were used to inoculate sterilized parent soils to assess the microbial community effects, while controlling for LC limitation. We found both LC limitation and microbial community responses led to significant declines in R_h by 37% and 30%, respectively, but their relative contributions were ecosystem specific. LC limitation alone caused a greater R_h decrease for DS soils than AMs or ASs. Our study demonstrates that soil carbon loss due to R_h in Tibetan alpine soils—especially in copiotrophic soils—will be weakened by microbial community responses under short‐term warming.     

Real microgravity condition promoted regeneration capacity of induced pluripotent stem cells during the TZ‐1 space mission

Induced pluripotent stem cells (iPSCs) are reprogrammed somatic cells that gained self‐renewal and differentiation capacity similar to embryonic stem cells. Taking the precious opportunity of the TianZhou‐1 spacecraft mission, we studied the effect of space microgravity (µg) on the self‐renewal capacity of iPSCs. Murine iPSCs carrying pluripotency reporter Oct4‐GFP were used. The Oct4‐EGFP‐iPSCs clones were loaded into the bioreactor and exposed to μg in outer space for 14 days. The control experiment was performed in identical device but on the ground in earth gravity (1 g). iPSCs clones were compact and highly expressed Oct4 before launch. In μg condition, cells in iPSC clones spread out more rapidly than those in ground 1 g condition during the first 3 days after launch. However, in 1 g condition, as the cell density increases, the Oct4‐GFP signal dropped significantly during the following 3 days. Interestingly, in μg condition, iPSCs originated from the spread‐out clones during the first 3 days appeared to cluster together and reform colonies that activated strong Oct4 expression. On the other hand, iPSC clones in 1 g condition were not able to recover Oct4 expression after overgrown. Our study for the first time performed real‐time imaging on the proliferation process of iPSCs in space and found that in μg condition, cell behaviour appeared to be more dynamic than on the ground.     

Design,synthesis and algicides activities of thiourea derivatives as the novel scaffold aldolase inhibitors

By using a new Fragment-Based Virtual Screen strategy, two series of novel FBA-II inhibitors (thiourea derivatives) were de novo discovered based on the active site of fructose-1, 6-bisphosphate aldolase from Cyanobacterial (CyFBA). In comparison, most of the N-(2-benzoylhydrazine-1-carbonothioyl) benzamide derivatives (L14～L22) exhibit higher CyFBA-II inhibitory activities compared to N-(phenylcarbamothioyl) benzamide derivatives (L1～L13). Especially, compound L14 not only shows higher CyFBA-II activity (K_i?=?0.65?μM), but also exhibits most potent in vivo activity against Synechocystis sp. PCC 6803 (EC₅₀?=?0.09?ppm), higher (7-fold) than that of our previous inhibitor (EC₅₀?=?0.6?ppm). The binding modes of compound L14 and CyFBA-II were further elucidated by jointly using DOX computational protocol, MM-PBSA and site-directed mutagenesis assays. The positive results suggest that strategy adopted in this study was promising to rapidly discovery the potent inhibitors with novel scaffolds. The satisfactory algicide activities suggest that the thiourea derivatives is very likely to be a promising lead for the development of novel specific algicides to solve Cyanobacterial harmful algal blooms (CHABs).     

Investigation of B,C-ring truncated deguelin derivatives as heat shock protein 90 (HSP90) inhibitors for use as anti-breast cancer agents

On the basis of deguelin, a series of the B,C-ring truncated surrogates with N-substituted amide linkers were investigated as HSP90 inhibitors. The structure activity relationship of the template was studied by incorporating various substitutions on the nitrogen of the amide linker and examining their HIF-1α inhibition. Among them, compound 57 showed potent HIF-1α inhibition and cytotoxicity in triple-negative breast cancer lines in a dose-dependent manner. Compound 57 downregulated expression and phosphorylation of major client proteins of HSP90 including AKT, ERK and STAT3, indicating that its antitumor activity was derived from the inhibition of HSP90 function. The molecular modeling of 57 demonstrated that 57 bound well to the C-terminal ATP-binding pocket in the open conformation of the hHSP90 homodimer with hydrogen bonding and pi-cation interactions. Overall, compound 57 is a potential antitumor agent for triple-negative breast cancer as a HSP90 C-terminal inhibitor.