Organic matter degradation state affects dissimilatory nitrate reduction processes in Knysna estuarine sediment,South Africa

Journal of Soils and Sediments - The quality of organic matter influencing sediment nitrate (NO3?) reduction processes in estuarine zones is not well understood. This study aimed to assess...     

台湾西南部优势竹类箣竹根力之研究

箣竹为台湾西南部泥岩地区早期主要造林树种,约占该地区绿蔽率之80%,形成极优势之植物。近年来因竹材价格低落,竹林之经营管理减少,其更新造林及其对坡面之保育功能之评价渐受重视。因此本研究为针对箣竹其根力特性,特进行根系与根域范围调查、根段拉力与植株引拔试验等,推估其坡面保育功效。研究结果为箣竹之根段拉力强度(Y)与其直径(X)成指数正相关,而箣竹之引拔抗力(F)与其胸高直径(D)成指数正相关。     

鸭绿江流域跨国界地区水土保持功能时空格局研究

以跨境的鸭绿江流域为研究区,基于多源数据,采用遥感解译、InVEST模型等手段,定量分析1988—2018年鸭绿江流域水土保持功能的变化,探讨二者间权衡/协同关系。结果表明：林地及耕地为流域内主要用地类型,2018年中国一侧、朝鲜一侧林地覆盖率分别为76.78%和75.84%;而耕地覆盖率分别为20.02%和21.63%。近30年来,流域水田面积变化率最大,中国、朝鲜两侧分别增长了330.63 %和127.52%。1988—2018年间流域中国一侧产水量增加118.40×10⁸ mm,朝鲜一侧产水量增加33.76×10⁸ mm;1988—2018年间流域中国一侧土壤保持量增加111.71×10⁸ t,朝鲜一侧土壤保持量增加102.61×10⁸ t。流域中国一侧水土保持功能呈现明显的协同关系,朝鲜一侧水土保持功能呈现协同—权衡—协同的变化态势。本研究为流域生态系统服务功能提升、可持续发展提供重要数据支撑。     

中国二熟耕作区粮食生产现状、潜力与对策

二熟耕作区是我国粮食生产的重点区域，其产量占全国总产量的53．2％。1985年以来该区粮食生产形势及生产格局发生了巨大变化，黄淮与江淮地区粮食总产量分别增长47．63％和61．67％，四川与西南地区粮食总产量增长43．76％和10．32％。二熟耕作区未来粮食增长的重点应放在黄淮与江淮地区，其技术对策为主攻高产田，大力抓好中低产田改造；选用优良品种，提高水肥利用效率，以提高综合效益，降低成本。     

不同行距配比对玉米光合生理指标及茎秆特性的影响

以‘大丰30’为试验材料,在同一密度下(75000株/hm²)设置5种不同行距配比,研究不同行距配比对玉米光合生理指标及茎秆力学特性的影响。结果表明:行距配比为40 cm×80 cm时,棒三叶的叶绿素含量(SPAD)在灌浆期达到峰值;行距配比为30 cm×90 cm时,棒三叶净光合速率在灌浆期最高。大口期开始,行距配比为40 cm×80 cm时,叶面积指数(LAI)最高。单株干物质积累量以40 cm×80 cm最高。各行距配比的茎秆硬皮穿刺强度与茎秆弯曲性能随着节位的下降均呈逐渐增强的趋势,从大到小为40 cm×80 cm>50 cm×70 cm>30 cm×90 cm>60 cm×60 cm>20 cm×100 cm。穗长、穗粗、千粒重和穗粒数各处理间均有不同变化,行距配比为40 cm×80 cm时产量最高,比等行距60 cm×60 cm增产7.96%。由此可见,行距配比为40 cm×80 cm,有利于大穗型品种‘大丰30’的光合性能和茎秆强度的提高,从而达到抗倒伏增产的目的。     

辣椒胞质雄性不育（CMS）基因型的鉴定方法

利用材料与不育系测交,F1代不育则材料的基因型为N（msms）;F1代全恢复则材料的基因型为N（MsMs）或S（MsMs）,为进一步判断,分别以其为母本与基因型为N（msms）的材料杂交,F2代分离出不育株的则其基因型为S（MsMs）;F1代一半不育,自交后分离,后代出现1/4不育株则材料的基因型为S（Msms）,否则...     

Effect of CHOP expression knock-down on apoptosis of renal tubular epithelial cells

AIM:To study the effect of C/EBP homologous protein (CHOP) on the apoptosis of renal tubular epithelial HK2 cells. METHODS:The serum mRNA levels of CHOP in the patients with acute kidney injury and healthy controls were detected by qPCR. In vitro, renal tubular epithelial HK2 cells were divided into control group, negative group (transfected with negative control siRNA), si-CHOP group (transfected with CHOP siRNA), and induced by transforming growth factor-β1 (TGF-β1). The viability of the cells was measured by MTT assay, and the apoptotic rate was analyzed by flow cytometry. The protein levels of nuclear antigen Ki-67, proliferating cell nuclear antigen (PCNA), caspase-3 and cleaved caspase-3 were determined by Western blot. RESULTS:Compared with the healthy controls, the serum mRNA levels of CHOP in the patients with acute kidney injury were increased significantly (P<0.05). Transfection with CHOP siRNA significantly decreased the expression of CHOP in the renal tubular epithelial HK2 cells (P<0.05). Knock-down of CHOP expression by siRNA significantly increased the viability of renal tubular epithelial HK2 cells (P<0.05), decreased the apoptotic rate (P<0.05), increased the expression of Ki-67 and PCNA (P<0.05), and down-regulated the protein level of cleaved caspase-3 (P<0.05). CONCLUSION:The serum mRNA levels of CHOP were increased in the patients with acute kidney injury. Knock-down of CHOP expression inhibits the apoptosis of renal tubular epithelial cells by regulating the expression of proliferation-and apoptosis-related proteins.     

低温驯化对菜豆内源多胺含量及其合成分解基因表达的影响

以7个菜豆品种为试材,采用对冷害指数以及相对电解质渗透率进行测定的方式,筛选出耐低温型菜豆品种和低温敏感型菜豆品种,并对其低温驯化过程中内源多胺含量进行测定,研究了腐胺、亚精胺和精胺在响应低温驯化过程中含量的变化,以及对多胺合成分解酶基因表达量的影响,以期为今后菜豆外施多胺缓解低温胁迫提供参考依据.结果 表明:在低温驯化过程中2个品种叶片中腐胺和亚精胺的含量有明显增加,而精胺含量变化规律不明显.在低温驯化过程多胺合成酶基因ADC表达量上升,ODC表达量变化不明显,SAMDC表达量升高,SPDS和SPMS在2个品种中表现不一致;多胺分解酶基因DAO和PAO表达量上升,SMO在2个品种中表现不一致.综上所述,腐胺和亚精胺在植物体内的积累可能与提高菜豆苗期耐低温性有较大关系,并且它们的积累可能与ADC、SAMDS、DAO和PAO的表达水平有关.     

Effectiveness and pathologic changes of transplantation of human mesenchymal stem cells in SOD1-G93A mouse model of familial amyotrophic lateral sclerosis

AIM: To study intravenous transplantation of human mesenchymal stem cells (hMSCs) on the life span and pathological change of SOD1-G93A amyotrophic lateral sclerosis (ALS) mice. METHODS: hMSCs were cultured and expanded from heparinized bone marrow cells from healthy donors and the purity and features were identified with FCM. hMSCs (3×106) resuspended in 0.3 mL DMEM or 0.3 mL DMEM only were injected into the tail vein of genotyped SOD1-G93A ALS mice. The mice were evaluated for signs of motor deficit with 4-point scoring system according to Weydt and the onset and life span were assessed. The pathological change was observed with Nissl staining and number of motor neuron was counted. RESULTS: The onset symptoms in untreated SOD1-G93A ALS mice appeared at (156.6±3.6) d of age and the average life span was (188.3±3.5) d. hMSCs transplantation delayed the onset of ALS type symptoms about 14 d and prolonged the life span about 18 d compared to the untreated SOD1-G93A littermates. The loss of motor neurons in untreated mice was much faster and severer than that in hMSCs transplanted mice. At 16 th week and 20 th week, motor neurons of untreated mice were significantly fewer than those of transplanted mice. β-globin gene in brain was detected in transplanted ALS mice. CONCLUSION: hMSCs migrate to central nervous system after intravenous transplantation, prolong the life span and delay the onset and motor neuron loss in SOD1-G93A ALS mice.