Combinations of Hd2 and Hd4 genes determine rice adaptability to Heilongjiang Province,northern limit of China

Heading date is a key trait in rice domestication and adaption, and a number of quantitative trait loci (QTLs) have been identified. The rice (Oryza sativa L.) cultivars in the Heilongjiang Province, t...     

25S rDNA在杨属植物染色体上的定位

利用荧光原位杂交技术对杨属(Populus)植物五个组中二倍体(2n=2x=38)代表种:毛白杨(P.tomentosa)、箭杆杨(P.nigravar.thevestina)、大叶杨(P.lasiocarpa)、小青杨(P.pseudo-simonii)、胡杨(P.euphratica);以及所发现的白杨组和黑杨组天然三倍体(2n=3x=57):毛白杨(P.tomentosa)、武黑1号(P.euramericana cv.Wuhei-1)进行了25S rDNA的染色体定位。二倍体毛白杨、箭杆杨、小青杨和大叶杨都具有4个25S rDNA位点,而胡杨只有2个较大的25S rDNA定位于1对小的染色体上,白杨和黑杨天然三倍体的两个种各有6个25S rDNA位点。同时作者还将杨属植物25S rDNA的分布变化与常规核型分析结果进行了比较。     

A generalization of Poisson-Sujatha distribution and its applications to ecology

A generalization of Poisson Sujatha distribution(AGPSD),which includes Poisson-Lindley distribution(PLD)and Poisson-Sujatha distribution(PSD)as particular cases,has been proposed and studied.Its moments and moments-based measures including coefficient of variation,skewness,kurtosis and index of dispersion have been obtained and their behaviors have been discussed.The estimation of its parameters has been discussed with maximum likelihood estimation.The applications of the proposed distribution has been explained through two examples of count data from ecology and the goodness of fit of the distribution has been compared with Poisson distribution,PLD and PSD.     

蜀葵种油的脂肪酸组成分析

The seed oil from Althaea rosea (L.) Caven was extracted with Hexane.After saponification and formation,the oil was determined by Capillary GC-MS.16 compounds have been determined and its unsaturation is 72.59%,Among them the content of linoleic acid is 69.24%.     

五个杨树品种生长、光合生理及根尖离子流速特性比较分析

通过比较不同品种杨树(Populus)的生长、光合生理及根尖离子流速特性差异，为速生适应性强品种的早期选育提供参考。以渤丰3号杨(P.×euramericana ‘Bofeng 3’)、渤丰1号杨(P.×euramericana ‘Bofeng 1’)、西雄1号杨(P.×euramericana ‘Xixiong 1’)、中雄7号杨(P.×euramericana ‘Zhongxiong 7’)和中雄4号杨(P. deltoides×P. suaveolens cl.‘Zhongxiong 4’)5个杨树品种1年生苗为研究对象，于正常培养条件下的试验开始和试验结束(30 d)时分别测定株高、地径等生长指标，并于10、20、30 d时分别测定幼苗的叶片数量、单叶面积、叶长、叶宽、瞬时净光合速率(Pn)、胞间CO2摩尔浓度(Ci)、气孔导度(Gs)、蒸腾速率(Tr)、叶绿素相对含量以及根尖K⁺、Ca²⁺、H⁺流速等指标，经过30 d的正常管理，5个品种的株高生长量之间的差异达到显著水平，由高到低依次为中雄4号杨、西雄1号杨、...     

Structure of intact human MCU supercomplex with the auxiliary MICU subunits

Dear Editor,Mitochondrial Ca2+homeostasis regulates energy production,cell division,and cell death.The basic properties of mitochondrial Ca2+uptake have been firmly established.The Ca2+influx is mediated by MCU,driven by membrane potential and using a uniporter mechanism(Vasington and Murphy,1962).Patch-clamp analysis of MCU currents demonstrated that MCU is a channel with exceptionally high Ca2+selectivity(Kirichok et al.,2004).     

PCR扩增试验的动力学数学模型

PCR技术已日趋成熟,但因为影响因素较多、反应过程比较复杂,直到目前PCR技术已创立近二十年,尚未能给出较好的描述PCR 反应的数学方法。我们根据它的基本原理提出了能够描述其反应过程的动力学方程：Wamp=［Ntarg×(1+P)n1+0.5×Cenz×U×P×Ceactiv×(n-n1)-Ntarg× (1+n×P)］×Cu×M,准确地描述了PCR反应的产物积累规律,建立了PCR反应的动力学数学模型。用动力学数学模型预测的PE 7700仪器的CT值与仪器的实际数值一致。动力学数学模型配合适当的监测设备可以构成自动化的PCR 定量仪器。PE 7700 仪器使用本动力学模型处理、分析数据,定量结果的准确性会更好。各实验室可根据各自的实验条件,由模型估算PCR产物数量,为PCR后产物继续处理提供较准确的数量信息。本模型阐明了PCR反应在多次循环后必然由指数扩增转变为线性扩增的分子基础,为定量PCR 提供了准确的计算方法。 Abstract:The PCR technique has been set up for nearly twenty years and is becoming more and more ripe.But because of the multiple influencing factors and complicated reaction procedures,no mathematical method that can describe the PCR reaction has been given.On the basis of its elementary principle,we suggested a kinetic equation to describe the reaction procedure,Wamp=［Ntarg×(1+P)n1+0.5×Cenz×U×P×Ceactive×(n-nl)-Ntarg×(1+n×P)］×Cu×M.This equation can describe correctly the accumulation rule of PCR product and thus build up the kinetic-mathematical model of PCR reaction.The predicted CT value of PE 7700 by the kinetic-mathematical model was in accordance with the real value detected by the machine.This kinetic-mathematical model accompanied by proper detecting equipment and computer could make an automatic PCR instrument,which would produce much better result.A laboratory can predict the amount of PCR product by this model and provide accurate information for further handling of PCR product according to its own condition.In this model,the molecular basis that PCR reaction is doomed to change from exponential amplification to linear amplification had been clarified.     

Identification of Immunodominant Th1-type T cell Epitopes from Schistosoma japonicum 28 kDa Glutathione-S-transferase,a Vaccine Candidate

Th1-type cytokines produced by the stimulation of Th1-type epitopes derived from definedschistosome-associated antigens are correlated with the development of resistance to the parasite infection.Schistosoma mansoni 28 kDa glutathione-S-transferase(Sm28GST),a major detoxification enzyme,hasbeen recognized as a vaccine candidate and a phase Ⅱ clinical trial has been carried out.Sheep immunizedwith recombinant Schistosoma japonicum 28GST(Sj28GST)have shown immune protection against theparasite infection.In the present study,six candidate peptides(P1,P2,P3,P4,P7 and P8)from Sj28GSTwere predicted,using software,to be T cell epitopes,and peptides P5 and P6 were designed by extendingfive amino acids at the N-terminal and C-terminal of P1,respectively.The peptide 190-211 aa in Sj28GSTcorresponding to the Th1-type epitope(190-211 aa)identified from Sm28GST was selected and named P9.The nine candidate peptides were synthesized or produced as the fusion protein with thioredoxin in thepET32c(+)/BL21(DE3)system.Their capacity to induce a Th1-type response in vitro was measured usinglymphocyte proliferation,cytokine detection experiments and flow cytometry.The results showed that P6(73-86 aa)generated the strongest stimulation effect on T cells among the nine candidate peptides,and drovethe highest level of IFN-γ and IL-2.Therefore,P6 is a functional Th1-type T cell epitope that is differentfrom that in Sm28GST,and will be useful for the development of effective vaccines which can triggeracquired immunity against S.japonicum.Moreover,our strategy of identifying the Th1-type epitope by acombination of software prediction and experimental confirmation provides a convenient and cost-savingalternative approach to previous methods.     

利用RAPD标记构建美洲黑杨×欧美分子标记连锁图谱

本文利用RAPD标记和美洲黑杨(Populus deltoides)×欧美杨(P.euramericana)的F1群体,构建了美洲黑杨×欧美杨的分子标记连锁图谱。实验过程中对1040个寡核苷酸随机引物进行了重复筛选,共选出127个引物用于作图群体(包括双亲共92个无性系)的随机扩增,这127个引物产生229个多态基因座,其中符合“拟测交”1∶1分离的有214个。利用多点连锁分析,形成19个连锁群及6个三连体和14个连锁对。由19个连锁群构成的图谱含标记129个,总图距为1914.2cM,覆盖杨树基因组约73.62％。标记间的平均间距为14.84cM。本研究获得了中等密度的美洲黑杨×欧美杨的一个连锁框架。 Abstract:A molecular linkage map was constructed for the parents of a P.deltoides × P.euramericana F1 family based on random amplified polymorphic DNA(RAPD)markers.A set of 1040 random oligonucleotide primers were screened and 127 primers were selected to generate RAPD markers within a sample of 90 F1 progenies.A total of 229 segregating loci were identified.Among the 229 loci,15 loci were found distorted from the normal 1∶1 ratio.Using multiple analysis,the 214 markers formed 19 main Linkage groups (including 129 markers)and b triples and 14 pairs.The resulting Linkage map of Populus deltoides × P.euramericana (including 129 markers)spanned 1914.2cM(73.62％ coverage of genome length)with an average distance of 14.84cM between markers.     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Coiled-coil nanomechanics and uncoiling and unfolding of the superhelix and alpha-helices of myosin

The nanomechanical properties of the coiled-coils of myosin are fundamentally important in understanding muscle assembly and contraction. Force spectra of single molecules of double-headed myosin, single-headed myosin, and coiled-coil tail fragments were acquired with an atomic force microscope and displayed characteristic triphasic force-distance responses to stretch: a rise phase (R) and a plateau phase (P) and an exponential phase (E). The R and P phases arise mainly from the stretching of the coiled-coils, with the hinge region being the main contributor to the rise phase at low force. Only the E phase was analyzable by the worm-like chain model of polymer elasticity. Restrained molecular mechanics simulations on an existing x-ray structure of scallop S2 yielded force spectra with either two or three phases, depending on the mode of stretch. It revealed that coiled-coil chains separate completely near the end of the P phase and the stretching of the unfolded chains gives rise to the E phase. Extensive conformational searching yielded a P phase force near 40 pN that agreed well with the experimental value. We suggest that the flexible and elastic S2 region, particularly the hinge region, may undergo force-induced unfolding and extend reversibly during actomyosin powerstroke.     

放牧对牧草光合作用、呼吸作用和氮、碳吸收与转运的影响

研究放牧对草地植物生理活动的影响,对于揭未草地放牧演替的生理机制有重要意义,大量研究表明,家畜放牧对牧草光合作用、呼吸作用以及C和N吸收与转运的影响,可以分为生理伤害和生理恢复2个阶段,放牧通过改变草地冠层结构影响牧草光合作用,净光合作用速率短期内迅速下降,随着叶面积指数增加又逐渐上升,呼吸作用有相似的变化趋势,牧草放牧后再生长所需的C和N最初主要来自根系和留茬中的贮藏物质,此后随着牧草生长恢复逐渐由同化作用供给,C代谢与土壤N水平负相关,放牧后牧草生理活动变化与牧草遗传特性、种间竞争、家畜放牧特征、非生物环境等因素密切相关。     

Synthesis of hapten and conjugates of coumestrol and development of immunoassay

3-O-Carboxymethylcoumestrol was prepared as the hapten for immunoassay by a partial alkylation of coumestrol with ethyl chloroacetate in acetone alkalized with potassium carbonate. 3-O-Ethoxycarbonylmethylcoumestrol was separated by column chromatography and finally was hydrolyzed with formic acid. 1H and 13C NMR data (APT, COSY, HMQC, and HMBC) revealed that the reaction was regioselective, as 3-O-ethoxycarboxymethylcoumestrol was the only monosubstituted derivative. The hapten was then conjugated to bovine serum albumin and used for immunization of rabbits. A radioimmunoassay (RIA) system was established based on the polyclonal antiserum and a 125I-labeled hapten-tyrosine methyl ester conjugate as the radioligand. Parameters of the RIA: sensitivity: 12 pg per tube, 50% intercept: 140 pg per tube, working range: 20-4000 pg per tube. The cross-reactivity of a panel isoflavonoid and lignan phytoestrogens was either negligible (e.g. formononetin 0.07%; biochanin A 0.06%) or not detectable at all. The major immunoreactive peak in HPLC fractions from an alfalfa extract had the same retention time as coumestrol standard and represented 94.8% of the signal. The remaining 5.2% of immunoreactivity was distributed between five minor peaks. We conclude that after the validation for particular matrices, the method will be a useful tool for analysis of coumestrol, especially in low volume and low concentration samples.     

Kinetics and thermodynamics of peroxidase- and laccase-catalyzed oxidation of N-substituted phenothiazines and phenoxazines

N -substituted phenothiazines (PTs) and phenoxazines (POs) catalyzed by fungal Coprinus cinereus peroxidase and Polyporus pinsitus laccase were investigated at pH 4–10. In the case of peroxidase, an apparent bimolecular rate constant (expressed as k _cat/K _m) varied from 1 ×10⁷M⁻¹s⁻¹to 2.6×10⁸M⁻¹s⁻¹ at pH 7.0. The constants for PO oxidation were higher in comparison to PT. pH dependence revealed two or three ionizable groups with pK _a values of 4.9–5.7 and 7.7–9.7 that significantly affected the activity of peroxidase. Single-turnover experiments showed that the limiting step of PT oxidation was reduction of compound II and second-order rate constants were obtained which were consistent with the constants at steady-state conditions. Laccase-catalyzed PT and PO oxidation rates were lower; apparent bimolecular rate constants varied from 1.8×10⁵M⁻¹s⁻¹ to 2.0×10⁷M⁻¹s⁻¹ at pH 5.3. PO constants were higher in comparison to PT, as was the case with peroxidase. The dependence of the apparent bimolecular constants of compound II or copper type 1 reduction, in the case of peroxidase or laccase, respectively, was analyzed in the framework of the Marcus outer-sphere electron-transfer theory. Peroxidase-catalyzed reactions with PT, as well as PO, fitted the same hyperbolic dependence with a maximal oxidation rate of 1.6×10⁸M⁻¹s⁻¹ and a reorganization energy of 0.30 eV. The respective parameters for laccase were 5.0×10⁷M⁻¹s⁻¹ and 0.29 eV. Received: 20 September 1999 / Accepted: 24 February 2000     

白术同源四倍体的诱导和鉴定及其与二倍体过氧化物酶的比较

以白术（Atractylodes macrooephala Koidz.）二倍体组培苗为材料,对其四倍体诱导方法进行研究,共获得45个白术同源四倍体株系,为优良株系的选育提供了材料。此外,还分析比较了其中8个白术四倍体株系与二倍体的过氧化物酶同工酶（POD）的酶谱差异,发现四倍体各株系过氧化物酶同工酶谱比二倍体的均多了Rf0.310的谱带,且总过氧化物酶比活力也发生了很大改变,对探讨白术四倍体优良株系的生理生化机理具有一定的参考价值。     

Morphology and putative function of the colon and cloaca of marine and freshwater snakes

Among tetrapods, evidence for postrenal modification of the urine by the distal digestive tract (including the colon and cloaca) is highly variable. Birds and bladderless reptiles are of interest because the colon and cloaca represent the only sites from which water and ions can be reclaimed from the urine secreted by the kidney. For animals occupying desiccating environments (e.g., deserts and marine environments), postrenal modification of the urine may directly contribute to the maintenance of hypo‐osmotic body fluids. We compared the morphology and distribution of key proteins in the colon, cloaca, and urogenital ducts of watersnakes from marine (Nerodia clarkii clarkii) and freshwater (Nerodia fasciata) habitats. Specifically, we examined the epithelia of each tissue for evidence of mucus production by examining the distribution of mucopolysaccharides, and for evidence of water/ion regulation by examining the distribution of Na⁺/K⁺‐ATPase (NKA), Na⁺/K⁺/Cl^? cotransporter (NKCC), and aquaporin 3 (AQP3). NKCC localized to the basolateral epithelium of the colon, urodeal sphincter, and proctodeum, consistent with a role in secretion of Na⁺, Cl^?, and K⁺ from the tissue, but NKA was not detected in the colon or any compartment of the cloaca. Interestingly, NKA was detected in the basolateral epithelium of the ureters, suggesting the urothelium may play a role in active ion transport. AQP3 was detected in the ureters and coprodeal complex, consistent with a role in urinary and fecal dehydration or, potentially, in the production of the watery component of the mucus secreted by the coprodeal complex. Since no differences in general cloacal morphology, production of mucus, or the distribution of ion transporters/water channels were detected between the two species, cloacal osmoregulation may either be regulated by proteins not examined in this study or may not be responsible for the differential success of N. c. clarkii and N. fasciata in marine habitats. J. Morphol. 2011. © 2011 Wiley Periodicals, Inc.