We investigated the biogeographic history of Kalopanax septemlobus, one of the most widespread temperate tree species in East Asia, using a combined phylogeographic and palaeodistribution modelling approach. Range-wide genetic differentiation at nuclear microsatellites (G'(ST) = 0.709; 2205 samples genotyped at five loci) and chloroplast DNA (G(ST) = 0.697; 576 samples sequenced for 2055 bp at three fragments) was high. A major phylogeographic break in Central China corresponded with those of other temperate species and the spatial delineation of the two temperate forest subkingdoms of East Asia, consistent with the forests having been isolated within both East and West China for multiple glacial-interglacial cycles. Evidence for multiple glacial refugia was found in most of its current range in China, South Japan and the southernmost part of the Korean Peninsula. In contrast, lineage admixture and absence of private alleles and haplotypes in Hokkaido and the northern Korean Peninsula support a postglacial origin of northernmost populations. Although palaeodistribution modelling predicted suitable climate across a land-bridge extending from South Japan to East China during the Last Glacial Maximum, the genetic differentiation of regional populations indicated a limited role of the exposed sea floor as a dispersal corridor at that time. Overall, this study provides evidence that differential impacts of Quaternary climate oscillation associated with landscape heterogeneity have shaped the genetic structure of a wide-ranging temperate tree in East Asia.
This study was conducted to assess the antioxidant capacity and protective effect of the ethyl acetate fraction from persimmon (Diospyros kaki) (EFDK) on H2O2-induced hippocampal HT22 cells and trimethyltin chloride (TMT)-induced Institute of Cancer Research (ICR) mice. EFDK had high antioxidant activities and neuroprotective effects in HT22 cells. EFDK ameliorated behavioral and memory deficits in Y-maze, passive avoidance and Morris water maze tests. Also, EFDK restored the antioxidant system by regulating malondialdehyde (MDA), superoxide dismutase (SOD) and reduced gluthathione (GSH), and the cholinergic system by controlling the acetylcholine (ACh) level and acetylcholinesterase (AChE) activity and expression. EFDK enhanced mitochondrial function by regulating reactive oxygen species (ROS) production, mitochondrial membrane potential (MMP), and adenosine triphosphate (ATP). Ultimately, EFDK regulated the c-Jun N-terminal kinase (JNK)/protein kinase B (Akt) pathway and apoptotic pathway by suppressing the expression of tumor necrosis factor-alpha (TNF-α), phosphorylated insulin receptor substrate 1 (IRS-1pSer), phosphorylated JNK (p-JNK), phosphorylated tau (p-tau), phosphorylated nuclear factor kappa-light-chain-enhancer of activated B cells (p-NF-κB), Bcl-2-associated X protein (BAX) and cytosolic cytochrome c, and increasing the expression of phosphorylated Akt (p-Akt) and mitochondrial cytochrome c. This study suggested that EFDK had antioxidant activity and a neuroprotective effect, and ameliorated cognitive abnormalities in TMT-induced mice by regulating the JNK/Akt and apoptotic pathway.
The complete chloroplast genome sequence of Hibiscus syriacus L. is presented in this study. The genome is composed of 161 019 bp in length, with a typical circular structure containing a pair of inverted repeats of 25 745 bp of length separated by a large single-copy region and a small single-copy region of 89 698 bp and 19 831 bp of length, respectively. The overall GC content is 36.8%. One hundred and fourteen genes were annotated, including 81 protein-coding genes, 4 ribosomal RNA genes and 29 transfer RNA genes.
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