光肩星天牛的脑部结构

通过Mallory和HE染色,对光肩星天牛Anoplophora glabnpenn脑部显微结构进行了观察.结果表明,光肩星天牛的脑由前脑、中脑、后脑三部分组成.前脑叶髓层包括一对蕈形体、一个中央体、一个脑桥体和一对附叶,其中每个蕈形体仅有一个帽状的蕈体冠.中脑触角叶较大,由九簇放射状排列的触角神经束组成,中央的一束较粗,说明其嗅觉发达.后脑较小.     

莱克多巴胺核酸适配体电化学生物传感器的研制

莱克多巴胺(RAC)被大量非法用于畜牧生产,易在动物组织残留,对人体造成危害。因此,研发灵敏、快捷的检测RAC的新方法是有效控制RAC滥用的关键环节之一。通过等温滴定量热法筛选到了一条对莱克多巴胺有高亲和力(Kd=1.66×10-6mol/L)的核酸适配体,利用该适配体作为识别分子成功的构建了莱克多巴胺适配体电化学生物传感器。差分脉冲伏安法分析,在0.5~1.0×102ng/ml浓度范围内,峰电流值的差值ΔIp与莱克多巴胺浓度的对数呈现良好的线性关系,相关系数R2=0.977 0,检测限达到0.1 ng/ml,反应时间为15 min。对同一浓度的莱克多巴胺重复检测7次,其峰电流值的RSD值为3.8%;说明该传感电极具有良好的检测重现性。不仅如此,该适配体传感器还具有良好的选择性。     

美洲大蠊Per a 9的抗原表位特征及三维结构建模

Per a 9是美洲大蠊主要过敏原蛋白之一。通过生物信息学方法了解美洲大蠊过敏原蛋白Per a 9的结构特征,为蟑螂变态反应性疾病的诊断和治疗提供线索。BLAST得到Per a 9相似序列,构建同源进化树,结果显示美洲大蠊Per a 9与德国小蠊精氨酸激酶在进化上具有较近的亲缘关系。Per a 9主要为α＋β结构的亲水性蛋白,其主要抗原表位集中于33—46、55—74、89—117、123—135、199—217、235—243、251—266、286—354区域。Motif预测其具有1个鸟嘌呤磷酸转移酶活性位点,6个蛋白激酶C磷酸化位点,7个酪氨酸激酶II磷酸化位点和2个N豆蔻酰化位点。其预测的三维结构基本能反应Per a 9真实的空间构象,这将为今后进一步了解和掌握Per a 9结构和功能的关系打下理论基础。     

豆豉纤溶酶基因在大肠杆菌中的可溶性表达及纯化(英文)

豆豉纤溶酶是从豆豉中发现的新型纤溶酶.从枯草杆菌DC-12中提取总DNA,PCR法扩增pro-DFE基因.将pro-DFE基因插入载体pET-32a,构建表达质粒pET-pro-DFE,转化大肠杆菌BL21(DE3),对重组菌株进行变温诱导表达,重组菌株于37℃培养至OD600为0.6时,加入终浓度为0.4mmol/L的IPTG于24℃进行诱导,SDS-PAGE显示可溶性重组融合蛋白约占重组蛋白的60%.且少量融合重组蛋白发生自切割,形成成熟的豆豉纤溶酶,破菌上清中含有成熟的豆豉溶栓酶,纤溶活性为200IU/mL.重组酶经纯化后比酶活为1280IU/mg.     

MicroRNA-146a抑制胶质瘤细胞增殖的研究

目的：检测胶质瘤中miR-146a的表达水平,并研究miR-146a对胶质瘤细胞增殖的影响。方法：应用实时定量PCR的方法检测胶质瘤组织和癌旁组织中miR-146a的表达水平,采用脂质体细胞转染miRNA模拟物的方式过表达miR-146a,MTT法检测转染后细胞的增殖率,利用在线软件targetScan预测miRNA可能的靶基因。结果：miR-146a在胶质瘤组织中表达明显降低（P〈0.01）,相对表达水平为癌旁组织的35%,细胞转染miR-146a模拟物后,miR-146a表达明显增加,癌细胞增殖率明显降低（P〈0.01）,仅为原细胞的47%。Notch1基因是miR-146a影响胶质瘤细胞增殖活力的可能靶基因。结论：miR-146a可能通过抑制Notch1基因的表达调控胶质瘤细胞的增殖。     

Pergolide Presynaptically Inhibits Calcium-Stimulated Release of γ-Aminobutyric Acid

The release of gamma-aminobutyric acid (GABA) in rat dorsolateral striatum was studied using in vivo microdialysis. Dialysis was conducted 2 days after probe implantation in awake, freely moving rats using a modified Ringer solution. Calcium induced a reversible increase in GABA release that was abolished by tetrodotoxin but was only slightly attenuated by a maximally effective dose of pergolide, a D2 receptor agonist. It was thus concluded that pergolide inhibits calcium-stimulated release of GABA presynaptically by a mechanism distinct from that of tetrodotoxin.     

携带siSPK1重组腺病毒的构建及其对N2a细胞凋亡的影响

应用AdMax腺病毒载体系统构建携带siSPK1基因的重组腺病毒,进一步研究SPK1基因对N2a细胞凋亡的影响。设计可形成小发夹结构的SPK1-siRNA模板cDNA序列,克隆至质粒pDC316-siRNA,构建SPK1-siRNA穿梭质粒pDC316-SPK1,经鉴定正确后,将pDC316-SPK1与辅助包装质粒（pBHG loxΔE1,3 Cre）共转染至HEK293细胞,包装纯化并扩增重组腺病毒颗粒,终点稀释法测定病毒滴度;病毒感染N2a细胞,Western blot法检测SPK1蛋白的表达;Hoechst33258染色检测SPK1基因对N2a细胞凋亡的影响。酶切后PCR分析、测序鉴定表明,pDC316-SPK1构建成功,病毒纯化后滴度为2.50E＋10 PFU/mL;重组病毒可在蛋白水平抑制SPK1的表达;SPK1基因抑制后,N2a细胞凋亡增加（P〈0.001）。上述结果表明,含有SPK1-siRNA的重组腺病毒构建成功,且具有抑制SPK1蛋白表达的功能,该基因沉默后,N2a细胞凋亡增加。     

The forensic use of luminol chemiluminescence to detect traces of blood inside motor vehicles.

The luminol test for blood was carried out on a set of interior fittings and surfaces inside three different makes of modern motor car. The surfaces and fittings provided little interference with the test for blood, although there was some detectable chemiluminescence when the test was applied to blood-free material from a seatbelt, a boot-lining and a gear-knob. The case with which haemoglobin samples could be washed off interior car surfaces was also examined for seat fabrics, carpets, roof-linings and various other plastic interior surfaces. A standard wash with water alone was not very effective and removed only ca. 50% of the haemoglobin. A standard wash with soapy water or with a proprietary multipurpose car cleaner removed ca. 90% of the haemoglobin from the tested surface. The effect of high car interior temperatures on haemoglobin samples that were subsequently used in the luminol test was also examined. It was shown that the sensitivity of the luminol test was not decreased but was increased by the prior heating of a haemoglobin sample. This effect was attributed to the thermal conversion of haemoglobin to the more brighter catalyst for chemiluminescence, methaemoglobin. The enthalpy of this conversion in the solid state was found to be 14.1 kJ/mol.     

大豆下胚轴可溶性蛋白中钙激活的蛋白激酶

大豆（Ｇｌｙｃｉｎｅ ｍ ａｘ Ｌ．） 下胚轴可溶性蛋白提取液进行自磷酸化,以ＳＤＳ－ＰＡＧＥ电泳分析其标记产物时发现,当有较高浓度的Ｃａ２＋ 存在于反应液中时,有一条１８ ｋＤ蛋白带被高强度标记,同时也可观察到另一条标记强度不高的６７ ｋＤ蛋白带． 当反应时间延长到１５ 或３０ｍ ｉｎ 时,它们的标记强度都逐渐减弱,最终从放射自显影底片上消失;在反应液中加入钙螯合剂ＥＧＴＡ 时,则只有６７ ｋＤ 被高强度标记;在磷酸化反应过程中加入非标记ＡＴＰ,蛋白中的３２Ｐ逐渐被非标记磷取代,表明反应体系处于磷酸化－脱磷酸化的平衡过程中,并有结果显示这一过程是钙依赖性的． 组蛋白Ｈ１ 可以使反应进程加快,表明提取液中的蛋白激酶可以利用它作为底物． 综合结果表明,１８ ｋＤ和６７ ｋＤ蛋白可能是具有自磷酸化能力且对Ｃａ２＋ 敏感的蛋白激酶,它们对Ｃａ２＋ 的不同反应,使得钙信号的传递更具可控性     

具有生物活性的川牛膝果聚糖的结构

从传统中药川牛膝(Cyathula offcinalis kuan)中分离提取到了一种具有生物活性的多糖RCP.核磁共振、甲基化分析、还原裂解和GC-MS分析揭示了RCP是一高度分支的果聚糖,它以(2→1)连接为骨架,其上有大量的(2→6)连接的分支,且属于新蔗果三糖系列.在93.17%果糖残基中,24.15%是末端果糖,26.24%是1-连接果糖,20.46%是6-连接果糖.在6.83%的葡萄糖残基中,2.14%是末端葡萄糖,4.69%是6-连接葡萄糖.RCP的平均聚合度是15.     

Female-induced sexual arousal in male mice and rats: behavioral and testosterone response

Exposure of a male mouse to a female mouse separated from it by a holed partition induced specific behavior and an increase in blood testosterone in the male. The male made more approaches to the partition and spent more time at it. The time spent by the male mouse over the first 10 min at the partition, behind which an estrus female was placed, was increased sixfold compared to the time spent by a male mouse exposed to the vacant neighboring compartment; and 1.5-fold compared to that spent by a male mouse exposed to a nonreceptive female or a male. Increased blood testosterone level was detected at 20 min of exposure to a receptive female in winter and at 40 min in summer. No variation in blood testosterone levels in the male mouse exposed to a nonreceptive female or a male was observed. Similar response to a receptive female placed in the neighboring compartment was shown in a male rat. The time spent by the male rat at the partition was 12 times higher when there was an estrus female behind it than in control. Blood testosterone in the male rat increased in response to a female rat and did not change in response to a male rat indicating female-induced motivation. It was concluded that the partition time might serve as a quantitative measure of sexual motivation in the males and that the model of female-induced sexual arousal used was suitable for studying both motivational and hormonal components of sexual arousal in male mice and rats.     

Hydrolysis of triglyceride by the whole cell of Pseudomonas putida 3SK in two-phase batch and continuous reactors systems

Batch and continuous hydrolysis of olive oil in an organic-aqueous two-phase system using the live whole cell of Pseudomonas putida 3SK as a source of a lipase is investigated. The strain was not only fully viable and grown well, but also produced extracellular lipase simultaneously. The degree of hydrolysis, depending on olive oil concentration in the solvents, was maximal at 13.5% (w/v) and decreased with the increase of the substrate concentration. At the optimal condition, a degree of hydrolysis higher than 95% was achieved with 24 h at 30 degrees C when the reaction was carried out in a two-phase batch stirred reactor. For long-term operation a continuous stirred reactor was designed. When the reaction was carried out in a continuous stirred reactor, the degree was hydrolysis reached 86% at a dilution rate of 0.2 h(-1). Satisfactory performance of a two-phase bioreactor was obtained in a long-term continous operation, which lasted for at least 30 days by feeding organic solvent containing olive oil and aqueous media separately. (c) 1994 John Wiley & Sons, Inc.     

Stimulation of avermectin B1a biosynthesis in Streptomyces avermilitis by feeding glucose and propionate

The biosynthetic ability of avermectin B1a in Streptomyces avermilitis was improved with propionate addition and glucose feeding. The results showed that B1a production was increased by 12.8–13.8% through supplement of 0.8% propionate at 24 h of cultivation. A stronger stimulation on B1a biosynthesis in S. avermilitis was observed by 3.0% glucose feeding at 5 d of cultivation. The B1a biosynthesis could be further enhanced by repeated glucose fed-batch process in a 10-l bench-top fermentor. A maximal B1a concentration of 780.0 mg/l was obtained by repeated 1.0% glucose addition on 4 d, 5 d and 6 d, which was 2.1-fold higher than that in a control fermentation. Corresponding with this, an additional 6.8% increase of B1a proportion was observed in comparison with the control process. This stimulation on avermectin B1a production was obvious even in a 2000-l fermentor under suitable control of aeration.     

Expression, purification, and characterization of a novel methyl parathion hydrolase

The mpd gene coding for a novel methyl parathion hydrolase (MPH) was previously reported and its putative open reading frame was also identified. To further confirm its coding region, the intact region encoding MPH was obtained by PCR and expressed in Escherichia coli as a hexa-His C-terminal fusion protein. The fusion protein was purified to homogeneity by metal-affinity chromatography. The enzyme activity and zymogram assay showed that the fusion protein was functional in degrading methyl parathion. The amino terminal sequencing of the purified recombinant MPH indicated that a signal peptide of the first 35 amino acids was cleaved from its precursor to form active MPH. A rat polyclonal antiserum was raised against the purified mature fusion protein. The results of Western blot and zymogram demonstrated that mature MPH in native Plesiomonas sp. strain M6 was also processed from its precursor by cleavage of a putative signal peptide at the amino terminus. The production of active MPH in E. coli was greatly improved after the coding region for the signal peptide was deleted. HPLC gel filtration of the purified mature recombinant MPH revealed that the MPH was a monomer.     

Purification and some properties of camel carboxypeptidase B

A carboxypeptidase B-like enzyme was purified 116-fold with a recovery of activity of 29% from a crude extract of camel pancreas by a four-step procedure consisting of two anion exchange chromatographies in succession, gel filtration and hydrophobic interaction chromatography. The enzyme was homogeneous on SDS and non-denaturing gel electrophoresis and on gel isoelectric focusing. Its molecular mass was found to be 31.5 kDa and its isoelectric point was estimated as 6.1. It was active towards a number of substrates that are cleaved by carboxypeptidases B from other species and was also susceptible to inhibition by inhibitors of such enzymes. The camel enzyme showed a pH optimum of 8.0 and it was seen to be a relatively potent kinase in vitro. The enzyme purified in this study was very similar to carboxypeptidases B isolated from other species in size, charge, substrate specificity and susceptibility to inhibition and thus it can be identified as camel carboxypeptidase B.     

Inter-plot competition in yield trials of potatoes (Solanum tuberosum L.) with single-drill plots

An experiment was carried out to assess the significance of inter-plot competition in a yield trial of potato cultivars. Seventeen cultivars were deliberately chosen and assessed for yield in single-drill and four-drill plots. Inter-plot competition for fresh-weight yield was a significant factor in the single-drill plots. It was modelled using a common competition coefficient with a covariate based on neighbour fresh-weight yields. In contrast, there was no statistically significant inter-plot competition for specific gravity. After adjustment for inter-plot competition, varietal ranking in estimated monoculture yield differed little from that based on unadjusted means. However, there was a reduction in the range of yield estimates, and a closer agreement with the observed pure-stand yields from the inner two drills of the four-drill plots. The adjustment for monoculture performance was most pronounced for the higher and lower yielding varieties, as expected from the assumption that the performance of high yielding varieties was enhanced in a competitive environment at the expense of low yielding ones. A general and flexible method of estimating competition coefficients in variety trials, together with a suitable algorithm, was developed and is explained in an appendix. It was used to check for inter-plot competition in a number of potato trials with single-drill plots and a large number of entries. Competition was found in some trials but not in others. Thus, where potato tubers are grown in single-drill plots for assessment of fresh-weight yield, adjustment should be made for inter-plot competition when evidence of inter-drill competition is found.     

米糠多糖的提取纯化及其成分结构和活性分析

研究米糠多糖（ｒｉｃｅ ｂｒａｎ ｐｏｌｙｓａｃｃｈａｒｉｄｅ,ＲＢＳ）的提取纯化方法,并对其进行组成成分,化学结构和物理性质分析以及活性测定,热水抽提法从稻糠中制取粗制ＲＢＳ多糖,层析分离纯化得到精制多糖,对精制多糖进行元素分析、糖和蛋白含量测定、红外特征吸收光谱测定和碳谱磁共振测定,以及对Ｂａｌｂ／ｃ小鼠同源Ｍｅｔｈ－Ａ纤维肉瘤抑瘤活性测定等。测定结果显示ＲＢＳ多糖为一种以α－１,４和α－１,     

The purification and characterization of a novel D(−)-specific carbamoylase enzyme from an Agrobacterium sp.

A carbamoylase enzyme was purified from a cell-free extract of Agrobacterium sp. with an overall yield of 81%. It was judged to be homogenous on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with a subunit molecular weight of 38,000 daltons. Further studies on the native enzyme suggested that the active enzyme was present as a dimer, with a pI of 5.5. It was able to cleave a variety of N-carbamoyl substrates, but was strictly D(−) specific. It was found to have a K_m of 0.82 m and a V_max of 31 U mg⁻¹ for D(−) N-carbamoyl hydroxyphenylglycine in the presence of 10 m dithiothreitol. It showed no metal ion requirements but was inhibited by iodoacetic acid and iodoacetamide, both thiol reagents. The N-terminal amino acid sequence of the enzyme was elucidated.     

嵌套式回归建立树木生物量模型

 该文介绍了一种建立树木生物量模型的简单快速方法——嵌套式回归。基本原理是以枝轴为基本单位, 逐级拟合。过程是把枝条分解成枝轴, 从枝轴到枝条, 再到单株, 拟合不同层次或尺度的生物量模型。建立枝轴生物量方程, 估计各级枝轴生物量, 将枝轴生物量(实测值或模拟值)总和起来便得到枝条生物量。由于样本单元之间有包含关系, 实际测定的样本很小, 具有快速实用的特点。检验结果显示, 模型预测值和实测值具有较高的一致性。     

抗菌肽Cec4a的重组表达和抗菌活性研究*

目的:构建Cec4a的原核重组表达体系,通过诱导表达、酶切纯化获得重组蛋白,并检测产物的抗菌活性。方法:基于Cec4a的序列设计引物,克隆Cec4a基因的DNA片段。利用原核表达载体(pCold-SUMO)构建重组原核表达质粒,并将其转化到大肠杆菌C41(DE3)等感受态细胞,使用IPTG进行诱导表达。通过Ni-NTA亲和层析柱纯化,获得含有His-SUMO标签的重组Cec4a融合蛋白。在SUMO蛋白酶酶切后,再次使用Ni-NTA亲和层析纯化,得到目的蛋白,最后用鲍曼不动杆菌(ATCC19606)作为指示菌检测表达产物的抗菌活性。结果:成功构建pCold-SUMO-Cec4a原核表达质粒,测序分析其序列与预期结果一致。Cec4a融合蛋白表达量为42.8mg/L,纯化后的Cec4a重组蛋白对鲍曼不动杆菌的MIC为4 μg/mL。结论:通过原核表达,并经Ni-NTA亲和层析纯化,获得了具有抗菌活性的重组蛋白Cec4a,为研究Cec4a的生物活性、抗菌机制及应用奠定了基础。