表观遗传修饰介导的植物胁迫记忆

植物因其固着生长的方式, 已经进化出各类特殊的机制来适应多变的外界环境。为提高自身的存活率, 植物进化出一类胁迫记忆机制, 以适应环境和保护自己。表观遗传修饰不仅能调控植物的正常生长发育, 而且参与植物对各种非生物或生物胁迫的响应。近年的研究表明, 表观遗传修饰在植物胁迫记忆调控中也发挥重要作用。例如, DNA甲基化、组蛋白甲基化及乙酰化等表观遗传修饰参与并维持特定的胁迫记忆。该文主要对表观遗传修饰介导的植物胁迫记忆最新进展进行综述, 并展望未来的重点和热点研究方向。     

Two closely linked tomato HKT coding genes are positional candidates for the major tomato QTL involved in Na+/K+ homeostasis

The location of major quantitative trait loci (QTL) contributing to stem and leaf [Na⁺] and [K⁺] was previously reported in chromosome 7 using two connected populations of recombinant inbred lines (RILs) of tomato. HKT1;1 and HKT1;2, two tomato Na⁺‐selective class I‐HKT transporters, were found to be closely linked, where the maximum logarithm of odds (LOD) score for these QTLs located. When a chromosome 7 linkage map based on 278 single‐nucleotide polymorphisms (SNPs) was used, the maximum LOD score position was only 35 kb from HKT1;1 and HKT1;2. Their expression patterns and phenotypic effects were further investigated in two near‐isogenic lines (NILs): 157‐14 (double homozygote for the cheesmaniae alleles) and 157‐17 (double homozygote for the lycopersicum alleles). The expression pattern for the HKT1;1 and HKT1;2 alleles was complex, possibly because of differences in their promoter sequences. High salinity had very little effect on root dry and fresh weight and consequently on the plant dry weight of NIL 157‐14 in comparison with 157‐17. A significant difference between NILs was also found for [K⁺] and the [Na⁺]/[K⁺] ratio in leaf and stem but not for [Na⁺] arising a disagreement with the corresponding RIL population. Their association with leaf [Na⁺] and salt tolerance in tomato is also discussed.     

The depth of Sooty Shearwater Ardenna grisea burrows varies with habitat and increases with competition for space

The Sooty Shearwater Ardenna grisea, an abundant but declining petrel, is one of many seabird species that construct breeding burrows, presumably because these confer protection from predators and the elements. Little is known about the causes of variation in Sooty Shearwater burrow architecture, which can differ markedly both within and between breeding sites. We hypothesize that burrow architecture varies in response to habitat type and competition for space. To address these hypotheses, we recorded Sooty Shearwater burrow dimensions on Kidney Island, the largest Sooty Shearwater colony in the Falkland Islands, South Atlantic, and modelled these as functions of burrow density (a proxy for competition) and habitat indices. Our models suggest that Sooty Shearwaters burrow further underground in response to competition for breeding space, and that soil underlying dense tussac grass Poa flabellata is more easily excavated than other substrates, indicating how vegetation restoration could aid the conservation of this species.     

我国若干地区蜡样芽孢杆菌723株噬菌体分型的初步报告

四年来,作者由水中获取蜡样芽孢杆菌噬菌体13株,旨在试作噬菌体分型。待检菌株共723株,由国内16个地区提供(其中食物中毒株121株;食品株602株)。分型结果显示:C29、C30、C24、C27、C19和A_4等型别占优势。中毒株     

Inhibition of the amino‐acid transporter LAT1 demonstrates anti‐neoplastic activity in medulloblastoma

Most cases of medulloblastoma (MB) occur in young children. While the overall survival rate can be relatively high, current treatments combining surgery, chemo‐ and radiotherapy are very destructive for patient development and quality of life. Moreover, aggressive forms and recurrences of MB cannot be controlled by classical therapies. Therefore, new therapeutic approaches yielding good efficacy and low toxicity for healthy tissues are required to improve patient outcome. Cancer cells sustain their proliferation by optimizing their nutrient uptake capacities. The L‐type amino acid transporter 1 (LAT1) is an essential amino acid carrier overexpressed in aggressive human cancers that was described as a potential therapeutic target. In this study, we investigated the therapeutic potential of JPH203, a LAT1‐specific pharmacological inhibitor, on two independent MB cell lines belonging to subgroups 3 (HD‐MB03) and Shh (DAOY). We show that while displaying low toxicity towards normal cerebral cells, JPH203 disrupts AA homeostasis, mTORC1 activity, proliferation and survival in MB cells. Moreover, we demonstrate that a long‐term treatment with JPH203 does not lead to resistance in MB cells. Therefore, this study suggests that targeting LAT1 with JPH203 is a promising therapeutic approach for MB treatment.     

Microwave‐assisted solid‐phase peptide synthesis of neurosecretory protein GL composed of 80 amino acid residues

We recently identified a novel cDNA encoding a small secretory protein of 80 amino acid residues, termed neurosecretory protein GL (NPGL), from the chicken hypothalamus. Homologs of NPGL have been reported to be present in mammals, such as human and rat. NPGL is amidated at its C‐terminus, contains an intramolecular disulfide bond, and is hydrophobic in nature. In this study, we have optimized the synthesis of the entire 80‐amino acid peptide sequence of rat NPGL by microwave‐assisted solid‐phase peptide synthesis. NPGL was obtained with a 10% yield when the coupling reactions were performed using 1‐[Bis(dimethylamino)methylene]‐1H‐1,2,3‐triazolo[4,5‐b]pyridinium‐3‐oxid hexafluorophosphate (HATU) at 50 °C for 5 min, and Fmoc deprotections were performed using 40% piperidine containing 0.1 M HOBt. Furthermore, the disulfide bond of NPGL was formed with 20% yield with the use of glutathione‐containing redox buffer and 50% acetonitrile. Copyright © 2015 European Peptide Society and John Wiley & Sons, Ltd.     

海南地区与环渤海湾美人鱼发光杆菌美人鱼亚种水产动物分离株的表型与遗传特征分析

美人鱼发光杆菌美人鱼亚种(Photobacterium damselae subsp.damselae,PDD)是一种广泛分布于海洋环境内的重要病原菌,可导致多种海洋生物患病死亡,近年来在我国不同养殖区域内均有发现和报道.[目的]通过生理代谢表型、毒力基因分布和分子遗传分析,系统比较我国海南地区和环渤海湾不同株系PDD...