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971.
Torreya Arn., a small genus of Taxaceae, consists of six species occurring in North America and eastern Asia. Several phylogenetic studies have previously been undertaken to reveal relationships within this genus, although only a few DNA segments or species were used. In the present study, we sequenced five Torreya plastomes and combined these with two existing plastomes from the genus to investigate plastome evolution and phylogenetic relationships within Torreya. All sequenced Torreya plastomes shared the same complement of 82 protein‐coding genes, 4 ribosomal RNA genes, and 31 transfer RNA genes. Phylogenetic inference using a maximum likelihood framework consisted of an 82‐gene, 17‐taxon dataset, including all species of Torreya, resolved Torreya as a monophyletic clade. Strongly supported relationships within the genus include the position of the early diverging T. jackii Chun, the two sister pairs T. fargesii Franch.–T. nucifera (L.) Siebold & Zucc. and T. grandis Fortune ex Lindl.–T. californica Torr., and the monophyly of the clade including T. fargesii var. yunnanensis, T. fargesii, and T. nucifera. In addition to the inference of species relationships, divergence time estimation and biogeographical analysis were carried out. The diversification of Torreya was estimated to be approximately 8.9 Ma. Ancestral state reconstruction of the geographical area suggested China/eastern North America as the most likely ancestral region for the six extant Torreya species.  相似文献   
972.
宋恒  王长泉 《植物学报》2013,48(4):461-469
茉莉酸是植物伤反应的特异激素, 在植物伤反应中具有核心作用, 其下游调控机制已经比较清晰。在番茄(Lycopersicon esculentum)伤反应中, 系统素和茉莉酸协同启动相关基因的表达, 行使系统性防御功能。拟南芥(Arabidopsis thaliana)信号肽是新发现的一类信号物质, 可以激活植物的初始免疫反应, 但其在伤反应中的作用机制有待进一步研究。脱落酸位于茉莉酸上游, 单独或者协同茉莉酸参与植物的防御反应。另外, 植物中还存在以核糖核酸酶为代表的且不依赖于茉莉酸的伤反应信号转导途径。该文对植物伤反应的防御机制和信号转导做了详细概述。  相似文献   
973.
目的:探讨N-乙酰半胱氨酸(NAC)对犬心房快速起搏电重构的影响。方法:取16只犬,随机分为对照组和NAC干预组。NAC组按照15mg/kg/d剂量给予NAC口服6周时间。在犬右房置入电极,快速起搏右心房,诱发房颤并维持2小时。在起搏前后分别测定有效不应期(AERP)。结果:房颤后对照组AERP显著缩短,AERP频率适应性下降(P<0.05);而NAC组房颤前后AERP和AERP频率适应性均无明显变化。结论:在心房快速起搏致房颤2h的模型中,NAC对心房电重构具有明显的保护作用。  相似文献   
974.
A comparative reaserch of the assembly of different porphyrin molecules on graphene oxide (GO) and reduced graphene oxide (RGO) was carried out, respectively. Despite the cationic porphyrin molecules can be assembled onto the surfaces of graphene sheets, including GO and RGO, to form complexes through electrostatic and π-π stacking interactions, the more obvious fluorescence quenching and the larger red-shift of the Soret band of porphyrin molecule in RGO-bound states were observed than those in GO-bound states, due to the differenc of molecular flattening in degree. Further, more interesting finding was that the complexes formed between cationic porphyrin and GO, rather than RGO sheets, can facilitate the incorporation of iron (III) ions into the porphyrin moieties, due to the presence of the oxygen-contained groups at the basal plane of GO sheets served as auxiliary coordination units, which can high-efficiently obstruct the electron transfer from excited porphyrin to GO sheets and result in the occurrence of fluorescence restoration. Thus, a fluorescence sensing platform has been developed for iron (III) ions detection in this contribution by using the porphyrin/GO nanohybrids as an optical probe, and our present one exhibited rapid and sensitive responses and high selectivity toward iron (III) ions.  相似文献   
975.
Thoracic aortic aneurysm (TAA), a serious cardiovascular disease that causes morbidity and mortality worldwide. At present, few biomarkers can accurately diagnose the appearance of TAA before dissection or rupture. Our research has the intention to investigate the developing applicable biomarkers for TAA promising clinically diagnostic biomarkers or probable regulatory targets for TAA. In our research, we built correlation networks utilizing the expression profile of peripheral blood mononuclear cell obtained from a public microarray data set (GSE9106). Furthermore, we chose the turquoise module, which has the strongest significance with TAA and was further analyzed. Fourteen genes that overlapped with differentially expressed proteins in the medial aortic layer were obtained. Subsequently, we verified the results applying quantitative polymerase chain reaction (Q-PCR) to our clinical specimen. In general, the Q-PCR results coincide with the majority of the expression profile. Fascinatingly, a notable change occurred in CLU, DES, MYH10, and FBLN5. In summary, using weighted gene coexpression analysis, our study indicates that CLU, DES, MYH10, and FBLN5 were identified and validated to be related to TAA and might be candidate biomarkers or therapeutic targets for TAA.  相似文献   
976.
张衡  樊伟  张健 《动物学研究》2009,30(1):109-112
2008年5月在崇明岛西端潮间带水域进行鱼类调查时,发现一尾长江河口及上海地区的鱼类新记录种——长身鳜,隶属鲈形目鮨科。主要特征如下:体较细长,近似圆筒形;头长,稍平扁。吻尖。口裂大,下颌明显突出;上颌达眼下方。前鳃盖骨后缘有10枚细锯齿,腹缘有向前倾斜的鳃盖骨棘2枚。鳃盖后端有1枚扁平棘,其上端有较小的短棘1枚。体黄褐色,头背和体侧具不规则的黑点和黑斑。近数十年来由于过度捕捞和水环境污染等原因,导致其资源量急剧减少,已被我国列入濒危动物红皮书。目前,关于长身鳜的资源状况研究十分薄弱,尤其是其繁殖习性、食性和发育等生物学特征研究还未见报道。因此,亟待开展此方面的研究和保护工作。  相似文献   
977.
ObjectiveHypothyroidism (HO) can induce significant metabolic dysfunction and increase cardiovascular disease risk. In the present study, we investigated the relationship between homocysteine (Hcy) and insulin resistance (IR) in patients with HO or subclinical hypothyroidism (SHO).MethodsA total of 270 subjects were enrolled. All subjects were divided into the following three groups: HO, SHO and control. Plasma levels of Hcy were measured, and each patient’s homeostatic index of insulin resistance (HOMA-IR) was calculated. Statistical analyses were carried out to evaluate the correlations among groups and to determine the predictors of IR in patients with HO or SHO.ResultsThe HOMA-IR value was significantly higher in the HO group than in the SHO and control groups. Plasma levels of Hcy were markedly increased in the HO group compared with those of the SHO group and controls. In addition, plasma levels of Hcy were positively correlated with the HOMA-IR values in both the HO and SHO groups. Multiple linear regression models showed that plasma levels of Hcy and free thyroxine (FT4) were the only predictors of HOMA-IR in patients with HO or SHO.ConclusionsPlasma levels of Hcy and HOMA-IR were increased in patients with HO or SHO. Our results suggest that HO and SHO may increase the risk for atherogenesis and cardiovascular disease by increased IR. The increased IR induced by hyperhomocysteinemia in patients with HO or SHO may partially explain this adverse effect.  相似文献   
978.
979.
梯棱羊肚菌Morchella importuna是一种可以大田覆土栽培的珍稀食用菌,而土壤重金属污染状况日益严重,对梯棱羊肚菌菌丝生长和子实体产品质量安全构成了潜在的威胁。本研究先采用镉离子胁迫处理梯棱羊肚菌菌丝体,RT-PCR检测发现候选基因ATX1的表达量显著下调。克隆梯棱羊肚菌ATX1基因,对ATX1p蛋白结构进行功能预测,发现ATX1p可能与铜离子转运及重金属胁迫相关。然后分别构建ATX1的超表达和RNAi基因沉默载体,采用农杆菌介导的转化方法,将其转入梯棱羊肚菌同核体菌株A50中,分别筛选到4个ATX1表达显著上调的超表达转化子和4个ATX1表达显著下调的RNAi基因沉默转化子,镉敏感性检测发现ATX1的RNAi基因沉默转化子表现为镉抗性增强,而ATX1超表达转化子则表现为镉抗性减弱。结果表明,梯棱羊肚菌ATX1基因表达与镉抗性呈负相关,ATX1p可能在梯棱羊肚菌镉胁迫响应过程中发挥着某种重要作用。  相似文献   
980.
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