EP300 contributes to high-altitude adaptation in Tibetans by regulating nitric oxide production

The genetic adaptation of Tibetans to high altitude hypoxia likely involves a group of genes in the hypoxic pathway,as suggested by earlier studies.To test the adaptive role of the previously reported candidate gene EP300 (histone acetyltransferase p300),we conducted resequencing of a 108.9 kb gene region of EP300 in 80 unrelated Tibetans.The allele-frequency and haplotype-based neutrality tests detected signals of positive Darwinian selection on EP300 in Tibetans,with a group of variants showing allelic divergence between Tibetans and lowland reference populations,including Han Chinese,Europeans,and Africans.Functional prediction suggested the involvement of multiple EP300 variants in gene expression regulation.More importantly,genetic association tests in 226 Tibetans indicated significant correlation of the adaptive EP300 variants with blood nitric oxide (NO) concentration.Collectively,we propose that EP300 harbors adaptive variants in Tibetans,which might contribute to high-altitude adaptation through regulating NO production.     

Genetic diversity and relationship of Fritillaria thunbergii Miq. landraces and related taxa

Genetic diversity and differentiation of four landraces of Fritillaria thunbergii Miq. and two congeners Fritillaria cirrhosa D. Don and Fritillaria anhuiensis S. C. Chen et S. F. Yin were evaluated using ISSR markers. The results showed that the genetic diversity of F. thunbergii was high at the specie level but relatively lower at the landrace level. A high level of genetic differentiation among four F. thunbergii landraces was detected based on the gene differentiation coefficient and the AMOVA, in line with the low inter-landrace gene flow. MS-tree analysis showed that the four F. thunbergii landraces were clustered on adjacent positions of the tree, and that Kuanye (Ft-KY) landrace was relatively distantly related to other landraces. In line with the MS-tree analysis, PCoA revealed that the three species of Fritillaria can be divided into two groups and three subgroups, among which there occurred a remarkable genetic differentiation.     

Retrieval Intention Modulates the Effects of Directed Forgetting Instructions on Recollection

The neurocognitive basis of memory retrieval is often examined by investigating brain potential old/new effects, which are differences in brain activity between successfully remembered repeated stimuli and correctly rejected new stimuli in a recognition test. In this study, we combined analyses of old/new effects for words with an item-method directed-forgetting manipulation in order to isolate differences between the retrieval processes elicited by words that participants were initially instructed to commit to memory and those that participants were initially instructed to forget. We compared old/new effects elicited by to-be-forgotten (TBF) words with those elicited by to-be-remembered (TBR) words in both an explicit-memory test (a recognition test) and an implicit-memory test (a lexical-decision test). Behavioral results showed clear directed forgetting effects in the recognition test, but not in the lexical decision test. Mirroring the behavioral findings, analyses of brain potentials showed evidence of directed forgetting only in the recognition test. In this test, potentials from 450–650 ms (P600 old/new effects) were more positive for TBR relative to TBF words. By contrast, P600 effects evident during the lexical-decision test did not differ in magnitude between TBR and TBF items. When taken in the context of prior studies that have linked similar parietal old/new effects to the recollection of episodic information, these data suggest that directed-forgetting effects manifest primarily in greater episodic retrieval by TBR than TBF items, and that retrieval intention may be important for these directed-forgetting effects to occur.     

SD-RLK28 positively regulates pollen hydration on stigmas as a PCP-Bβ receptor in Arabidopsis thaliana

Pollen hydration on dry stigmas is strictly regulated by pollen–stigma interactions in Brassicaceae. Although several related molecular events have been described, the molecular mechanism underlying pollen hydration remains elusive. Multiple B-class pollen coat proteins(PCP-Bs) are involved in pollen hydration. Here, by analyzing the interactions of two PCP-Bs with three Arabidopsis thaliana stigmas strongly expressing S-domain receptor kinase(SD-RLK), we determined that SD-RLK28 directly intera...     

Matrix metalloproteinase-9 induces cardiac fibroblast migration, collagen and cytokine secretion: inhibition by salvianolic acid B from Salvia miltiorrhiza

Cardiac fibroblasts play the key role in cardiac function and matrix metalloproteinases-9 (MMP-9) is a well known contributor to the development of myocardial remodeling. However, the direct regulation of MMP-9 on the function of cardiac fibroblasts and the underlying mechanism are far from elucidation. In the present research, recombinant protein encoding catalytic domain of MMP-9 (MMP-9 CD) was constructed and the function of neonatal cardiac fibroblasts was investigated by cell proliferation assay, migration assay, picrosirius red assay, multiplex cytokine assay and fibroblast phenotype detection. 200 nM MMP-9 CD stimulated cardiac fibroblasts migration (169.4±22.5% versus 100±0%, p<0.01), increased collagen synthesis (1.5±0.2 fold, p<0.05), up-regulated the secretion of ICAM (574.0±40.1 versus 268.5±8.6pg/ml, p<0.01), TNF-α (192.6±11.0 versus 14.4±1.8pg/ml, p<0.001), IL-6 (1500.9±70.2 versus 323.4±40.6pg/ml, p<0.001) and sVCAM-1 (30.3±4.3 versus 7.0±0.1 pg/ml, p<0.05) and down-regulated VEGF (436.5±148.9 versus 1034.3±28.1 pg/ml, p<0.05) significantly with modest effects on proliferation. Accompanying with these regulations, transition of fibroblasts to myofibroblast was confirmed by immunofluorescent stain of α-smooth muscle actin (α-SMA) with MMP-9 CD treatment. Furthermore, salvianolic acid B (SalB) inhibited the effects of MMP-9 CD significantly. In conclusion, our results provide evidence for a direct influence of MMP-9 on cardiac fibroblast migration, collagen and cytokine secretion, which can be attenuated by SalB.     

Oxygen‐Deficient Blue TiO2 for Ultrastable and Fast Lithium Storage

Developing a titanium dioxide (TiO₂)‐based anode with superior high‐rate capability and long‐term cycling stability is important for efficient energy storage. Herein, a simple one‐step approach for fabricating blue TiO₂ nanoparticles with oxygen vacancies is reported. Oxygen vacancies can enlarge lattice spaces, lower charge transfer resistance, and provide more active sites in TiO₂ lattices. As a result, this blue TiO₂ electrode exhibits a highly reversible capacity of 50 mAh g^?1 at 100 C (16 800 mA g^?1) even after 10 000 cycles, which is attributable to the combination of surface capacitive process and remarkable diffusion‐controlled insertion revealed by the kinetic analysis. The strategy of employing oxygen‐deficient nanoparticles may be extended to the design of other robust semiconductor materials as electrodes for energy storage.     

二甲基亚砜和吐温80对钝齿棒杆菌产生赖氨酸影响的研究

以赖氨酸产生菌钝齿捧杆菌（Corynebacteriumcrenatum）E0.7－66（HS ,AECrr,TArr,ESr）为出发菌种,对菌体进行亚硝酸诱变处理,并且通过提高抗七叶苷[1,2]剂量,筛选得到高抗七叶苷突变株E0.8-26,其L-赖氨酸产量较出发菌株提高了13．1％．在发酵至28h时,加入0．2％的吐温80或0.5％的二甲基亚砜,分别又使L-赖氨酸产量提高12．8％和13．3％。因此通过使用表面活性剂来改变细胞质膜造性,可使产酸量大幅度提高,该途径是筛过高产菌株的良好方法．     

Ferrous Iron Induces Nrf2 Expression in Mouse Brain Astrocytes to Prevent Neurotoxicity

Free radical damage caused by ferrous iron is involved in the pathogenesis of secondary brain injury after intracerebral hemorrhage (ICH). NF‐E2‐related factor 2 (Nrf2), a major phase II gene regulator that binds to antioxidant response element, represents an important cellular cytoprotective mechanism against oxidative damage. We hypothesized that Nrf2 might protect astrocytes from damage by Fe²⁺. Therefore, we examined cytotoxicity in primary astrocytes induced by iron overload and evaluated the effects of Fe²⁺ on Nrf2 expression. The results demonstrated that 24‐h Fe²⁺ exposure exerted time‐ and concentration‐dependent cytotoxicity in astrocytes. Furthermore, Fe²⁺ exposure in astrocytes resulted in time‐ and concentration‐dependent increases in Nrf2 expression, which preceded Fe²⁺ toxicity. Nrf2‐specific siRNA further knocked down Nrf2 levels, resulting in greater Fe²⁺‐induced astrocyte cytotoxicity. These data indicate that induction of Nrf2 expression could serve as an adaptive self‐defense mechanism, although it is insufficient to completely protect primary astrocytes from Fe²⁺‐induced neurotoxicity.