一个潜在催化莱鲍迪D苷合成的新型糖基转移酶

尿苷二磷酸糖基转移酶(uridine diphosphate glycosyltransferases,UGTs)催化糖基转移反应,与植物次生代谢密切相关。本研究根据甜叶菊(Stevia rebaudiana)转录组数据库,克隆到一个催化莱鲍迪D苷(rebaudioside D,RD)合成的新型糖基转移酶候选基因,对其开展生物信息学分析。结果表明,该基因开放阅读框长1380 bp,编码459个氨基酸,等电点(pI)预测为5.54,理论分子量约49.66 kD,系统发育分析表明该基因与向日葵中的UGT89A2同源,故将其命名为SrUGT89A2。构建pET28a-SrUGT89A2原核表达载体,并在大肠杆菌(BL21(DE3))中诱导表达得到重组蛋白,HPLC检测表明粗酶液能催化甜叶菊提取液形成一个新的色谱峰,该峰保留时间与莱鲍迪D苷一致。经进一步纯化UGT89A2蛋白,添加不同甜菊糖苷标准品为催化底物,但未鉴定出该蛋白催化的具体糖苷。该潜在催化甜菊糖RD苷合成的新型糖基转移酶基因SrUGT89A2的发现,为RD苷的生物合成和甜菊糖苷的生物途径研究提供新的理论依据。     

Effect of Kechuanning on airway remodeling and protein level of p-ERK1/2 in lung tissues of asthmatic rats induced by virus

AIM:To investigate the effect of Kechuanning on airway remodeling and the protein level of p-ERK1/2 in lung tissues of asthmatic rats induced by virus. METHODS:The asthmatic rat model induced by respiratory syncytial virus was established. The experimental rats were divided into normal group, asthma model group, low dose (0.33 mL/kg), middle dose (3.0 mL/kg) and high dose (10 mL/kg) of Kechuanning groups, and PD98059 (3 mg/kg) group. The airway responsiveness of the rats was measured by animal ventilator. The pathological changes of the lung tissues were observed by HE staining. PAS staining and Masson staining were used to observe goblet epithelial cells metaplasia and airway collagen deposition. The expression of matrix metalloproteinases-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) in the lung tissues of the rats was detected by immunohistochemical staining. The protein levels of ERK1/2 and p-ERK1/2 were determined by Western blot. RESULTS:Compared with model group, the airway responsiveness of the rats in middle dose and high dose of Kechuanning groups was significantly decreased (P<0.01), the injury of lung tissues was significantly decreased, the goblet epithelial cells metaplasia and airway collagen deposition were significantly reduced (P<0.01), and the expression of MMP-9 and TIMP-1 in the lung tissues was also significantly decreased (P<0.01). In addition, the protein level of p-ERK1/2 in high dose of Kechuanning group was significantly decreased compared with model group (P<0.01). CONCLUSION:Kechuanning may treat asthma by regulating the expression of p-ERK1/2 in the lung tissues and improving the airway remodeling symptoms of asthmatic rats induced by virus.     

多酚类化合物协同抗氧化性研究进展

多酚类化合物是一种大量存在于植物体内的物质，因其具有优良的抗氧化、抗癌、抗衰老等 性能而受到研究者们的广泛关注。多项研究表明具有抗氧化性能的物质之间大多具有协同作用，两 种或两种以上的物质化合，其抗氧化能力往往强于单一物质的抗氧化能力。近年来，许多研究者将目 光聚焦到多酚类物质与小分子物质化合所具有的协同抗氧化能力的研究上并做出多项试验。本文论 述了多酚类化合物的抗氧化机理及协同抗氧化机理，并以茶多酚与维生素C、维生素E 化合为例对协 同抗氧化进行论述。     

MYB转录因子参与植物非生物胁迫响应与植物激素应答的研究进展

基因的时空表达受转录因子的精确调控。植物在面对不利环境因素比如高温、低温、干旱、盐碱等胁迫时其细胞生理生化会迅速地从“舒适”状态转变进入“胁迫响应”状态。这种快速响应的状态转变依赖于植物对胁迫信号的感知及传递、激素通路(脱落酸、茉莉酸等)的激发、转录因子的活化等复杂的过程;最终植物通过胁迫相关基因的表达、次生代谢转变、抗氧化物质的积累等实现胁迫条件下细胞内环境的再平衡从而获得生存。植物MYB(v-MYB avian myeloblastosis viral oncogene homolog)转录因子就是上述转变中的重要参与者。本文介绍了植物MYB转录因子的结构特征、分类,综述了近些年来MYB转录因子与非生物胁迫,以及植物激素应答过程相关的研究进展。     

Effect of Jieyuwan on depression-like behaviors and expression of BDNF in hippocampus and prefrontal cortex of WKY rats

AIM:To investigate the mechanism of depression and its development, and to study the expression of brain-derived neurotrophic factor (BDNF) in the hippocampus and prefrontal cortex of Wistar-Kyoto (WKY) rats treated with Jieyuwan. METHODS:Adult male WKY rats were used as an animal model of endogenous depression. Wistar rats of the same strain were selected as control group. WKY rats were randomly divided into model group, citalopram group and Jieyuwan group. After intragastric administration for 21 d, the changes of depression-like behaviors were observed by sucrose preference test and forced swimming test. Immunofluorescence and Western blot were used to detect the expression of BDNF in the hippocampus and prefrontal cortex. RESULTS:WKY rats showed significant depression-like behaviors, and the expression of BDNF was significantly decreased in the hippocampus and prefrontal cortex (P<0.01). The reduction of neuronal axons in hippocampus was also observed. After drug treatment, the depression-like behaviors of WKY rats were significantly attenuated, and the expression of BDNF and the number of axons were increased (P<0.01). CONCLUSION:Jieyuwan effectively attenuates the depression-like behaviors of WKY rats, and BDNF is a key factor in its antidepressant effect. Our findings further confirm the involvement of BDNF in the development of depression.     

Shikonin reverses HGF-induced resistance to gefitinib in lung cancer cells HCC827

AIM: To investigate the effect of shikonin on reversing hepatocyte growth factor(HGF)-induced resistance to gefitinib in lung cancer HCC827 cells, and to explore its possible mechanisms.METHODS: The gefitinib-resistant HCC827 cells induced by HGF were treated with shikonin and gefitinibthe alone or in combination. The inhibition rates of cell viability were determined by MTT assay. The invasive ability of HCC827 cells with HGF-induced resistance to gefitinib was determined by Transwell assay. The protein levels of epithelial-mesenchymal transition (EMT) and related signaling pathway in the HCC827 cells were detected by Western blot.RESULTS: The results of MTT assay showed that the cell activity of HCC827 cells was significantly inhibited by shikonin in a dose dependent manner. The IC₅₀ of shikonin in HCC827 cells was 3.06 μmol/L. And the IC₅₀ of gefitinib in HCC827 cells was 0.51 μmol/L. Under the condition of combined treatment with shikonin and gefitinib in the presence of HGF (20 μg/L), the IC₅₀ of gefitinib was 7.36 μmol/L, significantly lower than that treated with gefitinib alone (P<0.01), so did the result of the cell migration (P<0.01). HGF induced EMT, while shikonin reversed this effect. The protein expression level of p-AKT was significantly up-regulated by HGF, while markedly down-regulated treatment with shikonin and gefitinib compared with gefitinib alone (P<0.01).CONCLUSION: Shikonin reverses HGF-induced resistance to gefitinib in lung cancer HCC827 cells, and the mechanism may be likely related to the preventon of EMT and the inhibition of HGF-induced activation of p-AKT signaling pathway.     

法氏囊活性肽在大肠杆菌中的克隆与表达

法氏囊活性肽（Bursin,BS)作为一种免疫增强剂，临床应用广泛，为了大量制备BS，按大肠杆菌惯用密码子合成BS基因。并用色氨酸将5个BS基因串联，克隆于质粒pU57的SmaI位点，经测序证明序列正确后，以PCR扩增，克隆于表达载体pBV220的EcoRI,HinDⅢ位点，温敏诱导表达，其表达水平占全菌总蛋白的13.4%。     

鸡传染性贫血病毒VP1、VP2基因在杆状病毒表达系统中的表达

将鸡传染性贫血病毒M9905株VP1、VP2基因分别或同时克隆到杆状病毒转移载体pFastBacDUAL中，然后转化到DHIOBAC感受态细胞中与Bacmid杆状病毒穿梭载体进行转座重组，最后将重组子转染Sf9昆虫细胞，得到分别或同时含VP1、VP2基因的重组杆状病毒rBacVP1、rBacVP2及rBacVP1—2。PCR扩增结果证实VP1、VP2基因重组到杆状病毒基因组中；SDS-PAGE电泳分析和间接免疫荧光试验结果表明VP1、VP2基因在重组病毒中得到了表达。     

Impact of postovulatory food deprivation on the ova transport, hormonal profiles and metabolic changes in sows.

The effect of food deprivation on ova transport, hormonal profiles and metabolic changes was studied in 20 crossbred multiparous sows during their second oestrus after weaning. To determine the time of ovulation, transrectal ultrasonographic examination was performed. The sows were divided into 2 groups, one control group (C-group), which was fed according to Swedish standards, and one experimental group (E-group). The E-group sows were deprived of food from the first morning meal after ovulation until slaughter. Blood samples were collected every second hour from about 12 h before expected ovulation in the second oestrus after weaning until slaughter and were analysed for progesterone, prostaglandin F2 alpha-metabolite, insulin, glucose, free fatty acids and triglycerides. All sows were slaughtered approximately 48 h after ovulation and the genital tract was recovered. The isthmic part of the oviduct was divided into 3 equally long segments and flushed separately with phosphate buffered saline (PBS). Uterine horns were also flushed with PBS. A significantly greater number of ova were found in the first and second part of the isthmus in the E-group (p = 0.05) while in the C-group most of the ova were found in the third part of the isthmus or the uterus (p = 0.01). The level of prostaglandin F2 alpha-metabolite was significantly higher in the E-group compared with the C-group. The concentration of progesterone increased in both groups after ovulation but there were no significant differences between the groups. The other blood parameters showed that the food-deprived sows were in a catabolic state. The 48 h period of fasting results, directly or indirectly in an delayed ova transport, which may be due to a delayed relaxation in the smooth circular muscle layer of the isthmus.     

小麦品种鄂恩一号和7023生期规律的对比观察与分析

通过对豫南小麦当家品种鄂恩一号和种植多年的7023的对比观察,找出二者在生育规律上的差异,进而分析在栽培措施上的异同。与7023相比,鄂恩一号出叶速度快,容易形成壮苗;抽穗后绿叶保持时间较长,有利后期光合作用;年前分蘖数比例大,总分蘖及成穗数没有7023多;幼穗分化开始早,进程快,小穗数及穗粒数比较少;开花早,灌浆时间长,灌浆强度大,子粒大,千粒重高。基于这些特点,提出了十月下旬播种,三叶期、药隔形成期追肥,四分子期根外喷肥,加强后期管理等针对该品种特性的栽培措施。