青藏高原典型冰川小流域土壤微生物生物量及胞外酶活性分布特征

土壤微生物释放的胞外酶是决定碳(C)、氮(N)、磷(P)生物地球化学循环的关键因素,为了阐明青藏高原典型小流域土壤微生物生物量和胞外酶活性沿海拔和土层的分布特征并揭示影响该分布格局的主要养分限制状况,于2021年8月采集了青藏高原廓琼岗日冰川小流域5个海拔梯度(4900 m; 5000 m; 5100 m; 5200 m; 5300 m)中4个土壤发生层(A层：腐殖质层、E层：淋溶层、B层：淀积层和C层：母质层)的土壤样品,定量分析了土壤基本理化性质、微生物生物量、胞外酶活性等指标。结果表明：1)微生物生物量碳氮磷的海拔差异变化规律不同,随着土层加深微生物生物量碳氮磷随海拔变化越小。同时,各海拔之间微生物生物量均有随土层加深而显著降低的趋势(P<0.05);2)四种酶活性的海拔间变化规律各异,但整体呈现随海拔升高而升高的趋势且在表层(A和E层)增长趋势更明显,而且随土层加深显著降低(P<0.05);3)该区域土壤微生物受到碳和磷共同限制,土层越深限制越高,而且海拔越高C限制越强,但P限制降低;4)青藏高原典型冰川小流域土壤微生物生物量和胞外酶活性在海拔和土层之间存在较明显的...     

青海湖岸带土壤与沉积物的地化特征与细菌群落对水位上升的响应

【目的】探究青海湖岸带土壤与沉积物的地化特征与细菌群落对水位扩张的响应。【方法】从岸上至岸下沿垂直青海湖岸带方向,采集距离湖面不同高度土壤(土壤：S1、S2)、岸边不同水深表层沉积物(过渡区：E0、E6、E17)及湖心表层沉积物(沉积物：D1、D2)样品,土壤与沉积物水深(土壤水深表示为负数)从小到大的变化表征岸边土壤被淹水转变为沉积物的过程。采用地球化学分析和16SrRNA基因高通量测序技术,探究岸带土壤与沉积物样品中的地化特征与微生物群落构成。【结果】青海湖水位上升导致的生境转变对岸带土壤与沉积物的理化性质、营养水平、有机碳类型等地化特征产生显著影响。具体表现为,随着水位升高,岸带土壤与沉积物的pH、矿物结合态有机碳含量显著升高,而碳氮比值、可溶性有机碳(dissolved organic carbon,DOC)、颗粒态有机碳含量显著下降。随着水位上升,青海湖岸带被淹没土壤的细菌群落多样性下降,且群落结构发生明显变化。这种变化与环境因子变化密切相关,具体表现为,细菌群落物种丰富度指数和香农多样性指数随着水位上升呈下降趋势;活性金属结合态有机碳含量与细菌群落多样性的变化密切相关;理化...     

酵母PHO2蛋白及其变异体与PHO5USA体外的相互作用

酵母ＰＨＯ２蛋白及其变异体与ＰＨＯ５ＵＳＡ体外的相互作用杨军,敖世洲（中国科学院上海生物化学研究所分子生物学国家重点实验室,２０００３１）关键词酵母;ＰＨＯ２;突变;ＤＮＡ结合ＰＨＯ２是酵母阻遏型酸性磷酸酯酶基因转录的正调控因子［１］,由５５９个氨基...     

Effects of ectomycorrhizal and vesicular-arbuscular mycorrhizal fungi on drought tolerance of four leguminous woody seedlings

Seedlings ofAcacia auriculiformis A. Cunn. ex. Benth.,Albizia lebbeck (L.) Benth.,Gliricidia sepium (Jac.) Walp andLeucaena leucocephala (Lam.) de Wit. were inoculated with an ectomycorrhizal (Boletus suillus (l. ex. Fr.) or indigenous vesicular-arbuscular mycorrhizal (VAM) fungi in a low P soil. The plants were subjected to unstressed (well-watered) and drought-stressed (water-stressed) conditions. InGliricidia andLeucaena, both mycorrhizal inoculations stimulated greater plant growth, P and N uptake compared to their non-mycorrhizal (NM) plants under both watering regimes. However, inAcacia andAlbizia, these parameters were only stimulated by either ectomycorrhiza (Acacia) or VA mycorrhiza (Albizia). Growth reduction occurred as a result of inoculation with the other type of mycorrhiza. This was attributed to competition for carbon betweenAcacia and VA mycorrhizas and parasitic association betweenAlbizia and ectomycorrhiza. Drought-stressed mycorrhizal and NMLeucaena, and drought-stressed mycorrhizalAcacia tolerated lower xylem pressure potentials and larger water losses than the drought-stressed mycorrhizal and NMAlbizia andGliricidia. These latter plants avoided drought by maintaining higher xylem pressure potentials and leaf relative water content (RWC). All the four leguminous plants were mycorrhizal dependent. The higher the mycorrhizal dependency (MD), the lower the drought tolerance expressed in terms of drought response index (DRI). The DRI may be a useful determinant of MD, as they are inversely related.     

Effects of different states of sheep fetal fibroblasts as donor cells on the early development in vitro of reconstructed sheep embryos

To investigate the effects of different states of donor cells on the development of reconstructed sheep embryos, we designed five treatments of donor cells, including cell passage, cell size, serum starvation,colchicine treatment and gene transfection. Results are as follows: ( Ⅰ ) Compared with 16-18 passage cells, the morula/blastocyst rate of 5-7 passage cells as donor nuclei was significantly higher (17.3%vs. 4.9%, P＜0.05), suggesting the advantage of short-time cultured cells in supporting the development of reconstructed embryos. (Ⅱ) The morula/blastocyst rate of reconstructed embryos derived from medium cells (15-25 μm) as donor nuclei was higher than that from large cells (25-33 μm) and small cells (8-15 μm)( 20.0% vs. 8.0%, 9.7%), indicating that reconstructed embryos from medium cells had a greater potentiality to develop into morula/blastocysts than those from small or large ones. (Ⅲ) The morula/blastocyst rate of reconstructed embryos from donor cells of SS (serum starvation) was lower than that from donor cells of NSS (non-serum starvation), but no significant difference was detected between SS and NSS( 11.8% vs. 18.6%, P＞0.05). (Ⅳ) Fetal fibroblasts treated with 0.05 μmol/L colchicine exhibited a higher morula/blastocyst rate of reconstructed embryos than those treated with 0.10 μmol/L colchicine and untreated ones (27.5% vs. 12.1%, 17.1%), however, no significant difference among the three treatments was detected (P＞0.05). (Ⅴ) The morula/blastocyst rate of reconstructed embryos from fetal fibroblasts transfected with GFP gene only was 3.1%, significantly lower than that from non-transgenic cells (3.1% vs. 20.4%, P＜0.05). In conclusion, our results demonstrated that fetal fibroblasts of fewer passages, medium size could ensure a higher morula/blastocyst rate of reconstructed embryos. Serum starvation of donor cells might be unnecessary to the development of reconstructed embryos. Donor cells treated with 0.05 μmol/L colchicine could facilitate the development of reconstructed embryos. Additionally, as cells transfected with GFP gene were used as donor nuclei, adverse effect on the development of reconstructed embryos was observed. Therefore, the developmental efficiency of reconstructed embryos could be improved if proper treatments to donor cells were used.     

蓝藻有机无机复混肥对几种作物的增效试验

研究了几种专用蓝藻有机无机复混肥,并对农作物进行了田间肥效试验。结果表明,施用蓝藻有机无机复混肥与普通N、P、K复合肥相比较,对烟草,西芹,韭菜,康乃馨等都有增产和改良土壤的效果。烟草试验表明,蓝藻复混肥的施用量以900kg/hm2效果最好,烟草产量、产值、上等烟比例分别比对照增加7.28%,5.04%,19.81%;西芹试验表明,施用蓝藻有机无机复混肥的各处理比对照高,其中以900kg/hm2和1200kg/hm2最高;其次是600kg/hm2;分别比对照高17.1%、16.3%和9.5%;而施用蓝藻有机无机复混肥900kg/hm2和1200kg/hm2,韭菜的株高、叶宽和产量比对照分别提高了12.21%和13.32%;康乃馨产花量则以施肥量为1200kg/hm2的最高,产花量为4865枝/100m2,比对照高11.6%。韭菜和土壤样品中未检测出藻毒素含量,表明使用蓝藻有机无机复混肥对植物和土壤是安全的。利用水华蓝藻生产有机无机复混肥,既解决了富营养化湖泊大量暴发的水华蓝藻的巨大生物量处置难题,又达到了改善环境、增加了经济和社会效益。       

Semi-automatic algorithm for construction of the left ventricular area variation curve over a complete cardiac cycle

Background  

Two-dimensional echocardiography (2D-echo) allows the evaluation of cardiac structures and their movements. A wide range of clinical diagnoses are based on the performance of the left ventricle. The evaluation of myocardial function is typically performed by manual segmentation of the ventricular cavity in a series of dynamic images. This process is laborious and operator dependent. The automatic segmentation of the left ventricle in 4-chamber long-axis images during diastole is troublesome, because of the opening of the mitral valve.     

甘草酸的提取及其抑菌活性研究

本文对甘草酸的各种提取方法进行了对比研究。结果表明,超声提取与传统搅拌提取、酶解提取及反复冻溶提取相比,是较适于从甘草中快速高效提取甘草酸的新方法,其最优条件为用20倍量0.7%氨水超声处理2次,每次20min。此外,探讨了提取的甘草酸的体外抑菌活性,其对金黄色葡萄球菌,大肠埃希氏杆菌,绿脓杆菌和枯草杆菌的最小抑菌浓度(MIC)分别为:0.0625,0.125,0.25,0.03125mg/mL,表明其具有较好的抑菌活性。     

肺病患者呼吸道曲霉随机扩增多态性DNA基因型分析

目的：了解肺病患者呼吸道曲霉基因分型状况,寻找肺部曲霉感染的可能来源,为曲霉感染的防治提供参考。方法：选择有呼吸道症状的患者925例作受试对象,收集其鼻腔、咽部分泌物及支气管肺泡灌洗液（bronchoal veolar lavage fluid,BALF）进行真菌培养、鉴定及随机扩增多态性DNA（random amplified polymorphic DNA,RAPD）基因分型分析。结果：在烟曲霉、黄曲霉和黑曲霉的RAPD带形图中,扩增条带数在1～11条之间,片断大小在150bp～2kb不等,不同菌株之间扩增条带的数量和扩增片断的大小均存在差异,即使带型完全一致的菌株,有些片断也存在亮度的差异。对分离自同一患者呼吸道不同部位的同种曲霉种内相似性比较的结果显示：虽然来自同一患者呼吸道不同部位的同种曲霉的形态学特征相同,但是基因型特征却存在差异。结论：通过呼吸作用进入肺组织内部的曲霉与患者鼻腔定植的同种曲霉存在差异,提示肺部曲霉的感染可能来源于患者周围的环境中,有效的控制环境中曲霉的污染程度是预防肺部曲霉感染的最有利的手段。     

两株链霉菌对非洲菊生长和生理生化指标的影响

本研究以非洲菊(Gerbera jamesonii)为试材,采用不同浓度的脱叶链霉菌FT05W和深蓝链霉菌ZEA17I孢子悬浮液浇灌盆栽非洲菊,筛选出非洲菊的最佳施用浓度,探索两株链霉菌对非洲菊生长和生理生化指标的影响,为非洲菊生产上科学合理施用链霉菌提供理论依据。结果表明: 脱叶链霉菌FT05W和深蓝链霉菌ZEA17I不同浓度孢子悬浮液均能有效促进非洲菊的生长,前者对非洲菊的作用效果优于后者,以浓度为1×10⁹ CFU·mL^-1的脱叶链霉菌FT05W效果最好。与蒸馏水对照相比,该处理显著促进了非洲菊株高(30.2%)和冠幅(41.5%)的生长,并在一定程度上促进了花茎的增长和增粗;能显著提高非洲菊植株叶片的叶绿素含量(65.2%)、根系活力(103.3%)和超氧化物歧化酶活性(84.4%),使丙二醛含量维持在较低的水平。因此在一定的浓度范围内,脱叶链霉菌FT05W和深蓝链霉菌ZEA17I均能有效促进非洲菊的生长,有利于非洲菊植株体内同化物的转运和积累,增强非洲菊植株抗逆性,特别是脱叶链霉菌FT05W具有在未来作为生物肥料解决非洲菊连作障碍的应用潜力。