翠竹及菲白竹LEA3同源基因的克隆及序列分析

竹类植物在中国有着非常悠久的栽培历史,并被广泛应用于园林、造林、庭院以及食品等行业。本研究以翠竹和菲白竹为材料提取其叶片总DNA,采用PCR方法获得翠竹SpLEA3基因与菲白竹SfLEA3-1、SfLEA3-2基因;其中SpLEA3全长804 bp,编码195个氨基酸,GC含量为68.4%;SfLEA3-1全长803 bp,编码195个氨基酸,GC含量为68.2%;SfLEA3-2全长557 bp,编码144个氨基酸,GC含量为67.8%。通过ProtParamy等生物软件分析,SpLEA3、SfLEA3-1和SfLEA3-2与贵州悬竹LEA3基因同源性高达61%以上,且3个基因编码蛋白均属于亲水性蛋白。源自2个竹种LEA3基因均包含一个完整的开放阅读框,其编码的氨基酸含有4~6个由11个氨基酸组成的保守基元序列。本研究不仅为深入了解竹类植物抗旱的分子机理研究提供了基础数据,也为竹类植物的抗旱育种后续研究提供了科学依据。     

60Co-γ射线对9种庭院月季扦插苗的辐射效应研究

为探讨⁶⁰Co-γ射线对不同庭院月季品种扦插苗的辐射诱变效应,以粉扇、金凤凰、梅朗口红、紫袍玉带、安吉拉、粉色达芬奇、你的眼睛、香槟和九重香9个庭院月季品种的扦插苗为研究对象,⁶⁰Co-γ射线为辐照源,设置不同剂量(0、25、45、60、80 Gy)进行辐射处理,测定了死亡率、萌芽率、变异率和主要的形态指标。结果表明,随着辐射剂量增加,月季扦插苗平均死亡率逐渐增加,从33.61%(0 Gy)上升至79.71%(80 Gy);植株生长受到显著抑制,植株变异率呈先升高后降低的趋势,辐射剂量为45 Gy时,植株变异率达到最高,占总体变异率(4.20‰)的64.70%。此外,不同品种月季对⁶⁰Co-γ射线辐射的敏感性不同,半致死辐射剂量也存在差异,其有效值介于26~55 Gy之间。综合⁶⁰Co-γ射线对月季扦插苗死亡率、生长势和变异率的影响,推荐庭院月季扦插苗的最适辐射剂量为45 Gy,这为月季辐射育种提供了理论基础。     

60Co-γ射线对睡莲生物学效应的影响

为探究辐射对睡莲的生物学效应,对2个睡莲品种弗吉尼亚(Nymphaea Virginia)和奥毛斯特(N.Almost black)的块茎进行不同剂量的⁶⁰Co-γ射线辐射处理。结果表明,2个睡莲品种的存活率均随辐射剂量的增加而下降,半致死剂量分别为24.342和27.671 Gy。5~10 Gy 剂量⁶⁰Co-γ辐射处理使睡莲叶面积和浮叶数显著增加,20~40 Gy剂量⁶⁰Co-γ辐射处理使叶面积和浮叶数显著减少。2个睡莲品种的开花时间均随辐射剂量的增加而延迟,但整个花期长度无显著变化。10~40 Gy剂量⁶⁰Co-γ辐射处理显著降低了睡莲花径,但对睡莲开花率无显著影响。辐射处理导致2个睡莲品种的叶片均出现红棕色斑块、锯齿、皱缩、小孔、卷曲、黄化等变异,且红棕色斑块的面积随着辐射剂量的增加而增大。辐射处理使黑红色花品种奥毛斯特出现普遍的褪色现象,而白色花品种弗吉尼亚的花色未发生变异。此外,经⁶⁰Co-γ射线辐射处理后2个睡莲品种均出现了花型变异的现象。本研究结果为利用辐射诱变技术选育睡莲新品种奠定了基础。     

TRMM在海河流域南系的降水估算精度评价及其对SWAT模型的适用性

准确估算区域降水对水文过程评价和水资源管理意义重大。为评估TRMM 3B42V7降水产品在海河流域南系的估算精度及其在土壤和水评估模型(Soil and Water Assessment Tool,SWAT)中的适用性,利用28个气象站降水观测数据(2007-2016年)和101个雨量站观测数据(2010-2016年)开展研究。研究表明:站点尺度上,3B42V7降水产品对月降水估算的均方根误差小于15 mm,平均误差小于8.5 mm;在湿润季节的估算精度更好。流域尺度上,日降水估算精度较差,相关系数小于0.6。分区尺度上,3B42V7能够很好地捕捉到不同等级降水强度,但对微量降雨有所低估;山区和平原的年降水量均出现高估现象,平原区较为突出;此外,3B42V7能够较好地捕捉到研究区内极端降水的时间和空间分布。分2种情景进行水文模拟,利用月平均流量对模型进行校准和验证,在情景Ⅰ中,验证期模拟结果较好,决定系数在0.56~0.96之间,纳什效率系数在-11.09~0.94之间。TRMM 3B42V7可为海河流域及其类似区域的水资源管理提供参考。     

CeO2添加比例对Fe基催化剂催化纤维素气化制氢的影响

为研究CeO2添加对生物质催化气化制氢特性的影响，该研究采用分级气化系统分析了不同CeO2/Fe2O3比例（Ce∶Fe摩尔比为0∶1、3∶7、5∶5、7∶3、1∶0）双金属催化剂对纤维素水蒸气催化重整制氢气体产物产量、组成以及催化剂的结构演变特性的影响。结果表明，CeO2/Fe2O3催化剂在制氢反应中的催化性能明显优于纯CeO2或Fe2O3催化剂，当Ce∶Fe摩尔比为3∶7时，在800℃下氢气的最大产率为21.63 mmol/g（以纤维素计，下同）；当温度大于等于800℃时，催化剂氧化还原反应后可生成CeFeO3，且CeFeO3的存在对纤维素水蒸气气化过程有促进作用。CeO2的引入提高了催化剂的氧化性能和稳定性，提高了使用寿命。该研究对生物质气化机制的深入理解具有一定的指导意义。     

Intensive organic vegetable production increases soil organic carbon but with a lower carbon conversion efficiency than integrated management

Intensive vegetable production in greenhouses has rapidly expanded in China since the 1990s and increased to 1.3 million ha of farmland by 2016, which is the highest in the world. We conducted an 11‐year greenhouse vegetable production experiment from 2002 to 2013 to observe soil organic carbon (SOC) dynamics under three management systems, i.e., conventional (CON), integrated (ING), and intensive organic (ORG) farming. Soil samples (0–20 and 20–40 cm depth) were collected in 2002 and 2013 and separated into four particle‐size fractions, i.e., coarse sand (> 250 µm), fine sand (250–53 µm), silt (53–2 µm), and clay (< 2 µm). The SOC contents and δ¹³C values of the whole soil and the four particle‐size fractions were analyzed. After 11 years of vegetable farming, ORG and ING significantly increased SOC stocks (0–20 cm) by 4008 ± 36.6 and 2880 ± 365 kg C ha^?1 y^?1, respectively, 8.1‐ and 5.8‐times that of CON (494 ± 42.6 kg C ha^?1 y^?1). The SOC stock increase in ORG at 20–40 cm depth was 245 ± 66.4 kg C ha^?1 y^?1, significantly higher than in ING (66 ± 13.4 kg C ha^?1 y^?1) and CON (109 ± 44.8 kg C ha^?1 y^?1). Analyses of ¹³C revealed a significant increase in newly produced SOC in both soil layers in ORG. However, the carbon conversion efficiency (CE: increased organic carbon in soil divided by organic carbon input) was lower in ORG (14.4%–21.7%) than in ING (18.2%–27.4%). Among the four particle‐sizes in the 0–20 cm layer, the silt fraction exhibited the largest proportion of increase in SOC content (57.8% and 55.4% of the SOC increase in ORG and ING, respectively). A similar trend was detected in the 20–40 cm soil layer. Over all, intensive organic (ORG) vegetable production increases soil organic carbon but with a lower carbon conversion efficiency than integrated (ING) management.     

Biochar addition mitigates nitrogen loss induced by straw incorporation and nitrogen fertilizer application

Biochar has been shown to be potentially beneficial for enhancing yields and soil properties, and diminishing nitrogen (N) losses. However, it remains unclear how biochar regulates soil carbon (C) and N to mitigate N losses induced by straw mixing with N fertilizer in dryland soils. Therefore, we investigated the effects of straw mixing (S₁), S₁ with biochar (SB) and no straw inputs (S₀), and routine urea application rates (N₁) and 70% of routine rates (N_0.7) on yields and N losses, and identify the relationship between N losses and soil C and N compounds. Results showed that N_0.7 and N₁ were suitable for the maize and wheat seasons, respectively, contributing to mitigating N losses without reducing crop yields. Moreover, in the maize season, N_0.7-SB significantly mitigated the straw-induced NH₃-N and N₂O-N emissions by 106% and 81%, respectively. In the wheat season, N₁-SB reduced the straw-induced NH₃-N and N₂O-N emissions by 35% and 66%, respectively. In addition, N_0.7-SB sharply reduced soil inorganic N (SIN) storage in the maize season. Furthermore, the NH₃-N and N₂O-N emission rates were negatively correlated with dissolved organic carbon/SIN content (0–20 cm) (DOC/SIN_0-20). N losses (N₂O-N and NH₃-N emissions and SIN storage) were positively correlated with SIN_0-20, but negatively correlated with soil organic carbon / SIN_0-20 (SOC/ SIN_0-20). This study provides further evidence that biochar with an appropriate N application rate decreased SIN_0-20 and increased DOC/SIN_0-20, thus reducing SIN storage and the straw-induced gaseous N emissions without decreasing crop yields.     

CUDC-907 induces DNA damage and autophagy in glioma cells

AIM:To investigate the effect of CUDC-907, a dual histone deacetylase (HDAC) and phosphatidylinositol 3-kinase (PI3K) inhibitor, on the DNA damage, cell cycle distribution and autophagy in human glioma U251 cells. METHODS:U251 cells were treated with CUDC-907 of different concentrations, and the cell viability was detected by MTT assay. The quantitative γ-H2AX foci were determined by laser scanning confocal microscopy. The cell cycle distribution of U251 cells was examined by flow cytometry. The protein expression was determined by Western blot analysis. RESULTS:CUDC-907 inhibited the cell viability and the phosphorylation of Akt and p70 ribosomal protein S6 kinase (p70s6K) in the U251 cells (P<0.05). In CUDC-907-treated cells, the number of γ-H2AX foci and protein expression of γ-H2AX were increased significantly (P<0.05). CUDC-907 also induced cell arrest in the G₂/M phase by up-regulating the expression of p21, and inhibiting the protein level of cyclin B1 and the phosphorylation of cell division cycle protein 2 (Cdc2). In addition, CUDC-907 triggered cell autophagy, and inhibition of autophagy increased CUDC-907-induced DNA damage of U251 cells. CONCLUSION:CUDC-907 significantly inhibits PI3K/Akt signaling pathway, induces DNA damage and arrests cell cycle in G₂/M phase. Blockage of autophagy promotes CUDC-907-induced DNA damage of U251 cells.     

Effect of FGFR1 expression knock-down on biological characteristics of infantile hemangioma endothelial cells

AIM: To study the effect of fibroblast growth factor receptor 1 (FGFR1) expression knock-down on the viability, apoptosis, invasion and migration of infantile hemangioma endothelial cells (HemECs). METHODS: FGFR1 was down-regulated by FGFR1 small interfering RNA (si-FGFR1) transfection. The viability of the cells was measured by CCK-8 assay. The apoptotic rate was analyzed by flow cytometry and the invasion and migration abilities were determined by Transwell assay. The protein levels of phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), and phosphorylated AKT (p-AKT) were examined by Western blot. RESULTS: Transfection of si-FGFR1 into HemECs had significant effects on inhibiting cell viability (P<0.05), promoting apoptosis (P<0.05), and decreasing cell invasion and migration abilities (P<0.05). The results of Western blot showed that knockdown of FGFR1 gene expression in the cells reduced the protein levels of PI3K and p-AKT (P<0.05), and had no significant effect on AKT protein level. CONCLUSION: Knock-down of FGFR1 expression changes the biological characteristics of endothelial cells in infantile hemangiomas by regulating PI3K/AKT signaling pathway.     

Doxycycline upregulates autophagy to modulate the levels of inflammatory cytokines in LPS-stimulated THP-1 cells

AIM:To analyze the effect of autophagy on inflammatory response regulated by doxycycline in lipopolysaccharide (LPS)-stimulated THP-1 cells and to investigate its molecular mechanism. METHODS:A human monocyte/macrophage cell line THP-1 was stimulated with LPS to establish an cell model of inflammatory response, and the cells were treated with doxycycline. The cytokines, such as tumor necrosis factor-α (TNF-α) and interleukin-8 (IL-8), in cell culture supernatant were measured by ELISA for evaluating the inflammatory levels. For determining the level of autophagy and its effect on inflammatory cell signaling pathways, the protein levels of LC3B, nuclear factor κB (NF-κB) and phosphorylated mammalian target of rapamycin (p-mTOR) were determined by Western blot. 3-Methyladenine (3-MA), an autophagy inhibitor, and rapamycin, an autophagy inducer, were used to study the effect of autophagy on inflammatory response regulated by doxycycline in LPS-stimulated THP-1 cells. RESULTS:The levels of TNF-α and IL-8 were increased rapidly and peaked at 12 h in LPS-stimulated THP-1 cells (P<0.05). Doxycycline significantly inhibited LPS-induced cytokine production in the THP-1 cells. Doxycycline up-regulated LPS-induced autophagy in THP-1 cells and doxycycline itself was an autophagy inducer. The protein levels of p-mTOR was up-regulated by LPS and down-regulated by doxycycline, suggesting that doxycycline induced autophagy via mTOR-dependent pathway while LPS through mTOR-independent pathway. Further studies showed that the combination of LPS, rapamycin and doxycycline inhibited the protein levels of NF-κB, and rapamycin increased the inhibitory effect of doxycycline on cytokine releases. Conversely, 3-MA, the autophagy inhibitor, attenuated the inhibitory effect of doxycycline on NF-κB and cytokine production. CONCLUSION:Autophagy is involved in the process of doxycycline modulating LPS-induced inflammatory response in the THP-1 cells.