落叶松人工林细根动态与土壤资源有效性关系研究

树木细根在森林生态系统C和养分循环中具有重要的作用。由于温带土壤资源有效性具有明显的季节变化, 导致细根生物量、根长密度 (Rootlengthdensity, RLD) 和比根长 (Specificrootlength, SRL) 的季节性变化。以 17年生落叶松 (Larixgmelini) 人工林为研究对象, 采用根钻法从 5月到 10月连续取样, 研究了不同土层细根 (直径≤ 2mm) 生物量、RLD和SRL的季节动态, 以及这些根系指标动态与土壤水分、温度和N有效性的关系。结果表明 :1) 落叶松细根年平均生物量 (活根 +死根 ) 为 189.1g·m-2 ·a-1, 其中 5 0 %分布在表层 (0~ 10cm), 33%分布在亚表层 (11~ 2 0cm), 17%分布在底层 (2 1~ 30cm) 。活根和死根生物量在 5~ 7月以及 9月较高, 8月和 10月较低。从春季 (5月 ) 到秋季 (10月 ), 随着活细根生物量的减少, 死细根生物量增加 ;2 ) 土壤表层 (0~ 10cm) 具有较高的RLD和SRL, 而底层 (2 1~ 30cm) 最低。春季 (5月 ) 总RLD和SRL最高, 分别为 10 6 2 1.4 5m·m-3 和 14.83m·g-1, 到秋季 (9月 ) 树木生长结束后达到最低值, 分别为 2 198.2 0m·m-3 和 3.77m·g-1;3) 细根生物量、RLD和SRL与土壤水分、温度和有效N存在不同程度的相关性。从单因子分析来看, 土壤水分和有效N对细根的影响明显大于温度, 对活根的影响大于死根。由于土壤资源有效性的季节变化, 使得C的地下分配格局发生改变。各土层细根与有效性资源之间的相关性反映了细根功能季节性差异。细根 (生物量、RLD和SRL) 的季节动态 (5 8%~ 73%的变异 ) 主要由土壤资源有效性的季节变化引起。     

植物着丝粒结构及进化的研究进展

植物着丝粒是染色体重要结构域,介导动粒装配。不同物种间着丝粒重复序列快速趋异进化,着丝粒功能保守,确保有丝分裂和减数分裂过程中染色体正确分离和准确传递。伴随染色质免疫共沉淀技术(Chromatin immunoprecipitation, ChIP)、ChIP 与高密度芯片相结合技术(ChIP-chip)、ChIP 与高通量测序相结合技术(ChIP-seq)的应用,植物着丝粒研究获得里程碑式进展:某些模式植物着丝粒DNA 序列、蛋白质结构、功能获得大量新认识;着丝粒基本蛋白质组蛋白H3 被用来界定着丝粒大小和边界;某些非着丝粒区域被激活为新着丝粒,在世代传递中保持稳定性。本文对植物着丝粒结构、功能、进化研究进行了综述,并探讨了植物着丝粒研究存在的问题。     

光敏核不育水稻61kD特异性蛋白质的纯化和N—端序列分析

用制备型聚丙烯酰胺凝胶电泳和制备型等电聚焦纯化了曾报道的光敏核不育水稻 (Oryza sativa)农垦 58S叶绿体的特异性蛋白质 P2 ,得到 SDS- PAGE和等电聚焦 (IEF )纯的 P2。经 SDS- PAGE和 IEF测定 ,该纯蛋白质的分子量是 61 k D,等电点是 5.8。现称 P2为 P61。氨基酸序列分析表明 P61的 N-端氨基酸序列与水稻和大麦叶绿体 ATPaseβ亚基的 N-端氨基酸序列同源。     

Specific molecular marker of the genes controlling linolenic acid content in rapeseed

In rapeseed, which is an agronomically important oilseed, variation in the linolenic acid content of the oil has been obtained through chemical mutagenesis treatment. Conventional breeding of this quantitative trait, however requires specific molecular markers. By means of biochemical experiments, we have established that the induced variation in linolenic acid content is associated with the fad3 gene encoding the microsomal ¹⁵ desaturase. Using a pair of primers specific to this gene and a doubled haploid progeny derived from a low linolenic x high linolenic acid F₁hybrid, we have identified a polymorphism of the fad3 alleles between the low- and the high-linolenic acid genotypes. The structure exon/intron of the fad3 DNA sequence seems to be very similar to that of the Arabidopsis fad3 gene. The choice of the primer pair allows specific amplification of one of the two rapeseed fad3 genes. The value and contribution of specific markers to conventional plant breeding is discussed.     

槟榔核心资源品质鉴定和特异种质筛选

为培育槟榔(Areca catechu)优良新品种,对10份核心资源品质进行鉴定和相关性分析.结果表明,不同种质资源的品质性状存在显著差异,9个性状的变异系数为7.00％～190.13％,其中,表儿茶素含量的变异系数最大,鲜果横径的最小.相关性分析表明,鲜果纵径与槟榔碱含量呈极显著正相关,与没食子酸含量呈显著负相关.基...     

基因芯片技术在病原细菌检测中的应用

基因芯片技术具有快速、高通量、平行化等优点,在病原细菌检测中有广泛的应用前景,选择细菌适宜的靶基因是芯片制备的关键之一。用细菌核糖体基因做靶基因的芯片技术,虽然应用广泛,但仍存在一些不足,随着基因组信息及基因功能的深入研究,包括毒力基因、耐药基因等具有较好种属特异性的细菌基因不断被发现,为芯片技术检测病原细菌提供了更多特异的靶基因,使检测结果更加灵敏、准确,在病原细菌研究中将发挥更大的作用。     

Cell cycle phase dependent productivity of a recombinant Chinese hamster ovary cell line

A Chinese Hamster Ovary cell line, CHO1-15₅₀₀, producing recombinant human tissue type plasminogen activator (tPA) via the dihydrofolate reductase (DHFR) amplification system, was studied in batch culture. In this system both DHFR and tPA are under the control of the strong constitutive viral SV40 early promoter. Employing the cumulative viable cell-hour approach, the specific productivity of tPA had maxima in the lag (0.065 pg cell⁻¹ h⁻¹) and early decline (0.040 pg cell⁻¹ h⁻¹) population growth phases. The viable population was assigned into four subpopulations (G1, S, G2/M phase, and Apoptotic cells) using flow cytometric analysis. As expected, intracellular DHFR was maximally expressed during the S cell cycle phase. The production of tPA, however, was found to be a direct linear function of the G1 phase, with a subpopulation specific productivity of 0.080 pg c-h⁻¹. Productivity maxima in the lag and early decline corroborate the flow cytometric data, indicative that this recombinant tPA production occurs primarily in the G1 cell cycle phase, not the S phase. This suggests that endogenous regulatory mechanisms are important controlling influences on the production of recombinant tPA in this ovarian cell line. Productivity from recombinant cell lines cannot be inferred from either the plasmid construct or the host cell alone. Elucidation of the relationship between expression of recombinant protein and the cell cycle phases of the host cell is a major component of the characterization of the animal cell production system. This information facilitates rational process design, including operating mode, modelling and control, and medium formulation.     

Optimization of free ammonia concentration for nitrite accumulation in shortcut biological nitrogen removal process

A shortcut biological nitrogen removal (SBNR) utilizes the concept of a direct conversion of ammonium to nitrite and then to nitrogen gas. A successful SBNR requires accumulation of nitrite in the system and inhibition of the activity of nitrite oxidizers. A high concentration of free ammonia (FA) inhibits nitrite oxidizers, but unfortunately decreases the ammonium removal rate as well. Therefore, the optimal range of FA concentration is necessary not only to stabilize nitrite accumulation but also to achieve maximum ammonium removal. In order to derive such optimal FA concentrations, the specific substrate utilization rates of ammonium and nitrite oxidizers were measured. The optimal FA concentration range appeared to be 5–10 mg/L for the adapted sludge. The simulated results from the modified inhibition model expressed by FA and ammonium/nitrite concentrations were shown very similar to the experimental results.     

Development of specific PCR primers for the detection of Rhizoctonia solani AG 2-2 LP from the leaf sheaths exhibiting large-patch symptom on zoysia grass

Detection of Rhizoctonia solani AG 2-2 LP isolates causing large-patch disease on zoysia grass was done using polymerase chain reaction (PCR). Specific primers were designed based on an amplified region using random amplified polymorphic DNA (RAPD)-PCR. Fifteen primers and three cultural types of R. solani AG 2-2 (types IIIB, IV and LP) were used for RAPD-PCR. The banding patterns by RAPD-PCR showed that the three cultural types were clearly distinguishable. A dendrogram constructed from the results of RAPD-PCR showed that the three cultural types of AG 2-2 clustered separately. The sequence of one PCR-amplified region which appeared only in LP isolates using primer A09 was selected for designing specific primers. Primer pair A091-F/R gave a single product from pure fungal DNA of LP isolates but not from those of the other two types (IIIB and IV), R. solani AG 1, 2-1, 2-3, 2-tulip, 3-10 and BI isolates and other turfgrass fungal pathogens. Primer pair A091-F/R also gave a single product from diseased leaf sheaths and this product was in accordance with those of pure fungal DNA of LP isolates. Primer pair A091-F/R did not yield PCR product from healthy leaf sheaths. The frequencies of detection of LP isolates from leaf sheaths of zoysia grass using PCR with primer pair A091-F/R were higher than those of the conventional isolation technique. These results showed that the PCR-based technique using specific primers A091-F/R is useful for the rapid detection of LP isolates from leaf sheaths of zoysia grass exhibiting large-patch symptoms.     

脑血康胶囊联合巴曲酶对急性脑梗死患者血清 MBP、NSE水平的影响

摘要 目的：研究脑血康胶囊联合巴曲酶对急性脑梗死患者血清髓鞘碱性蛋白(myebin bosic protein,MBP)、神经元特异性烯醇化酶(neuron-specific enolase,NSE)水平的影响。方法：选择2018年3月～2019年3月我院收治的161例急性脑梗死患者,将其随机分为两组。对照组静脉滴注巴曲酶,首次给予10 BU,隔日给予5 BU,每两天给药1次;观察组在巴曲酶的基础上联合口服脑血康胶囊,每天3 次,每次3粒。观察和比较两组治疗总有效率、治疗前后血清MBP、NSE、全血黏度(whole blood viscosity,WBV)、红细胞压积(hematocrit,HCT)、血浆黏度(plasma viscosity,PV)和纤维蛋白原(fibrinogen,FIB)水平及NHISS和BI评分的变化。结果：治疗后,观察组的有效率为91.25 %,明显高于对照组(64.2%,P<0.05);两组血清MBP、NSE、WBV、HCT、PV和FIB水平均较治疗前明显降低(P<0.05),且观察组的以上指标明显低于对照组(P<0.05);两组的BI评分明显升高(P<0.05),NHISS评分明显降低(P<0.05),观察组BI评分明显高于对照组,而NHISS评分明显低于对照组(P<0.05)。结论：脑血康胶囊联合巴曲酶对急性脑梗死有显著的疗效,能明显降低患者血清MBP、NSE水平,促进神经功能的恢复。