水稻RIL群体芽期耐冷性基因的分子标记定位

水稻芽期冷害是我国长江中下游的早稻种植区和东北、西北稻区及云贵高原的一季稻区水稻生产中的重要限制因子之一。研究中利用纸卷法测定1个水稻重组自交系群体对10℃低温的芽期耐冷性,结合1张高密度分子遗传图谱,进行QTL定位分析。检测到控制水稻芽期耐冷性的4个QTL,分别位于1、3、7和11号染色体上。其中,位于11号染色体上的QTL qSCT-11的效应最大,在10℃低温处理13d时,对性状的贡献率达26％～30％,被检测到的LOD值也高达16～19,其加性效应值为正,增效等位基因存在于亲本Lemont中,RM202为与QTL qSCT-11紧密连锁的SSR标记。该主效QTL的增效基因,可作为分子标记辅助选择的操作对象用于水稻芽期耐冷性的遗传改良。     

水稻低温发芽性QTL的分子标记定位

利用1个粳／籼交来源的重组自交系群体,采用纸卷法在15℃低温条件下进行发芽试验,在发芽培养的6～14d中每天观测统计1次发芽率(％)。结合一张含有198个DNA标记的连锁图谱,用复合区间作图法定位水稻低温发芽性QTL。共检测到7个主效应QTL,分别位于水稻1、3、5、6和8号染色体上,单个QTL对性状的贡献率为5％～16％。其中,位于3号染色体标记区间RM148-RM85的qLTG-3-2和位于8号染色体标记区间RM223-RM210的qLTG-8-1对性状的贡献率最大,分别达16％和14％。QTL qLTG-3-2在发芽培养6～10d中表达,其效应由强渐弱,对性状的贡献率由发芽培养6d时的16．4％逐渐降低为发芽11d时的5．1％;而QTL qLTG-8-1则在发芽培养9～14d中起作用,其效应值由小逐渐增大,对性状的贡献率由发芽9d时的8．6％逐渐上升为发芽13～14d的14％。尽管这2个QTL加性效应的大小在低温发芽过程中按一定趋势变化,但加性效应的方向始终是一致的。QTL qLTG-3-2的增效基因来源于亲本特青,而QTL qLTG-8-1的增效基因来自于亲本Lemont。这2个QTL的增效等位基因有望作为分子标记辅助育种的操作对象,用于水稻品种低温发芽性的遗传改良。     

水稻红莲型CMS育性恢复QTL分析

红莲型CMS是在我国杂交水稻生产中被广泛利用的雄性不育细胞质之一。为了同时定位红莲型CMS育性恢复主效和微效QTL,利用红莲型CMS不育系粤泰A(YTA)与“Lemont／特青”RIL群体测交,结合1张含有198个DNA分子标记的高密度遗传图谱,对测交F1群体的小穗育性和花粉育性进行复合区间作图。在对YTA的育性恢复性方面,该。RIL群体的2个亲本之间具有明显差异,特青的恢复性较强,其测交F1的小穗育性和花粉育性分别为72％和51％;而Lemont测交F1的小穗育性和花粉育性分别为32％和9％。复合区间作图定位到4个育性恢复QTL,分别位于水稻第1、2和10号染色体上,单个QTL的贡献率在5％～24％之间。其中,除1个QTL的增效基因来源于Lemont外,其余3个QTL的增效基因均来源于特青。效应最大的QTL为qRF-10-1,该QTL位于10号染色体RM258-C16标记区间,对小穗育性表型变异的贡献率为24％,对花粉育性的贡献率为17％,且该QTL被检测到的LOD值显著较高,因此是1个主效QTL,其增效基因来源于特青。除了主效QTLqRF-10-1外,其它3个QTL对性状的贡献率均在10％以下(5％～8％)。由此表明,该RIL群体对红莲型CMS的育性恢复由1个主效QTL控制,并受其它几个微效QTL的影响。该QTL定位结果与小穗育性在测交F1群体中呈连续的双峰分布的结果相一致。与主效QTL qRF-10-1紧密连锁的SSR标记为RM258,该主效QTL可作为分子标记辅助育种的操作目标之一,用于杂交稻分子育种中培育红莲型CMS的强恢复系。     

水稻籼粳交DH群体苗期耐冷性基因的分子标记定位

水稻苗期低温冷害导致的烂秧现象是水稻生产中重要的限制因素之一。以一个水稻籼粳交(圭630／02428)DH群体为材料,在幼苗3叶1心时用10℃低温处理3d,随后恢复培养,以恢复培养5d后的秧苗成活率(％)为指标,鉴定该DH群体的苗期耐冷性。利用已构建的RFLP连锁图谱和基于混合线性模型的定位软件QTLMapper1.0对水稻苗期耐冷性进行QTL分析,检测到控制水稻苗期耐冷性的3个QTLs,分别位于第3、11、12染色体上,贡献率分别为7．9％、18．3％和24.4％,其增效等位基因均来自于亲本“02428”。同时检测到控制水稻苗期耐冷性的上位性互作位点8个,分散分布于第2、7、8、9、11染色体上,其中有2对互作的贡献率在15％左右,这2对互作的增效基因型均为来自2个亲本的重组基因型。苗期耐冷性在2个亲本间差异很大,在DH群体中呈现出连续变异,有明显的超亲分离。这些结果表明,水稻苗期耐冷性是受多基因控制的数量性状,基因的上位性互作是其重要的遗传基础之一。     

水稻芽期耐冷性的QTL分析

本研究以98个Nipponbare/Kasalath//Nipponbare回交重组自交家系(backcross-inbred lines,BILs)组成的群体为材料,进行水稻芽期耐冷性数量性状基因座的检测和遗传效应分析.25℃正常条件下水稻发芽7 d,芽长5～10 cm,5℃低温处理10d,之后升温至25℃,缓苗10d,调查活苗率,并以活苗率作为芽期耐冷性的表型值,分析亲本和98个BILs的芽期耐冷性表现.采用Windows QTL Cartographer 1.13a软件的复合区间作图法,共检测到4个苗期耐冷性数量性状基因座(quantative trait locus,QTL),分别位于第3、第7和第12染色体上,命名为qSCT-3-1、qSCT-3-2、qSCT-7和qSCT-12.4个QTL的加性效应分别为11.16、11.14、-8.8和-14.59,可解释表型变异的12.11%,12.66%,6.82%和15.86%.     

两种肥力水平下水稻苗高QTL的比较分析

利用一个来源于粳／籼交组合的水稻重组自交系群体进行盆栽试验,设正常肥力(对照CK)和低肥力(不施肥)2个处理,分别在播种后25d(时期Ⅰ)和50d(时期Ⅱ)取样测定秧苗的苗高。结合一张含有198个标记的高密度分子遗传图谱,对性状进行复合区间作图。共检测到8个水稻苗高QTL,分别位于第1、3、5、6、8和10号染色体上,各QTL对性状的贡献率为4％～12％。通过对2种肥力水平下水稻苗高QTL的比较分析,发现大多数QTL只在1种肥力水平下表达,QTL与不同肥力水平之间存在着显著的互作。唯一一个在2种肥力水平下均能稳定起作用、而且加性效应的方向一致的QTL是qSH-3-2,该QTL位于3号染色体标记区间RM156-RM16,其加性效应值为正,增效基因来自于亲本Lemont。此外,有3个QTL(qSH-1、qSH-3-3和qSH-5)在2个抽样时期均起作用,且加性效应的方向一致。对利用分子标记辅助选择改良水稻品种的耐低肥特性的育种策略进行了讨论。     

直播水稻茎鞘非结构碳水化合物积累与转运的遗传剖析

为了揭示水稻（Oryza sativa）茎鞘非结构碳水化合物（nonstructural carbohydrate, NSC）积累与转运的遗传基础, 在大田直播条件下, 利用来源于Lemont/特青的重组自交系群体, 对5个相关性状进行了QTL定位。始穗期和成熟期共检测到3个茎鞘NSC含量QTL, 分别位于第1、9和12染色体上, 贡献率分别为13%、7%和7%, 增效等位基因均来自特青。检测到的2个NSC转运率QTL均位于第12染色体上, 贡献率分别为8%和14%。检测到的结实率和千粒重QTL分别为3个和4个, 3个结实率QTL的贡献率分别为9%、24%和6%, 4个千粒重QTL的贡献率分别为14%、11%、12%和13%。进一步的分析表明,来自Lemont的等位基因降低成熟期茎鞘NSC含量的同时却能提高NSC转运率、结实率和千粒重, 而来自特青的等位基因对NSC转运率和结实率均有增效作用, 这为性状间表型相关提供了重要的遗传解释。     

直播水稻茎鞘非结构碳水化合物积累与转运的遗传剖析

为了揭示水稻(Oryza sativa)茎鞘非结构碳水化合物(nonstructural carbohydrate, NSC)积累与转运的遗传基础, 在大田直播条件下, 利用来源于Lemont/特青的重组自交系群体, 对5个相关性状进行了QTL定位。始穗期和成熟期共检测到3个茎鞘NSC含量QTL, 分别位于第1、9和12染色体上, 贡献率分别为13%、7%和7%, 增效等位基因均来自特青。检测到的2个NSC转运率QTL均位于第12染色体上, 贡献率分别为8%和14%。检测到的结实率和千粒重QTL分别为3个和4个, 3个结实率QTL的贡献率分别为9%、24%和6%, 4个千粒重QTL的贡献率分别为14%、11%、12%和13%。进一步的分析表明,来自Lemont的等位基因降低成熟期茎鞘NSC含量的同时却能提高NSC转运率、结实率和千粒重, 而来自特青的等位基因对NSC转运率和结实率均有增效作用, 这为性状间表型相关提供了重要的遗传解释。     

直播条件下水稻6个穗部性状的QTL分析

在大田直播条件下,利用来源于＂Lemont/特青＂的重组自交系群体,对水稻6个穗部性状及其相互间遗传相关的分子基础进行了QTL分析,共检测到19个QTL,各性状QTL数为2～4个,单个QTL贡献率为4%～22%。共检测到3个染色体区段能同时影响多个穗部性状,其中第1染色体RM212-RM104和第2染色体RM263-RM221区段的QTL能同时影响单株产量、每穗颖花数、着粒密度和二次枝梗数中的3个或4个性状,且这2个区段的QTL对各性状的效应方向相同,增效等位基因均来自‘特青’,为各性状间表型正相关提供了重要的遗传解释。第11染色体RG1022附近的QTL对着粒密度的效应值为负,来自‘特青’的等位基因增加性状值,而对穗长的效应值为正,来自‘特青’的等位基因降低性状值,为这2个性状间表型负相关也提供了一定的遗传解释。此外,对水稻穗部性状QTL在多种环境和遗传背景下的稳定表达及其在分子标记辅助育种中的应用进行了讨论。     

水稻苗期低温失绿的遗传分析及基因定位

在早季低温条件下, 籼稻品种Dular的幼苗表现出白化失绿, 而粳稻品种Lemont幼苗表现正常绿色。以Lemont和Dular作亲本构建一个F2群体,通过该群体在早季低温条件下性状的表现,发现Lemont和Dular苗期耐冷性的差异受单个主基因控制,低温下白化失绿等位基因为隐性。将该基因暂时命名为cisc(t)。利用该F2群体,采用集团分离分析(BSA)法将cisc(t)定位在9号染色体上。经过对F2群体中100个典型的白化单株的简单序列长度多态性分析,将该基因定位在5.5 cM的区间内,分别与微卫星标记RM257和RM242相距3.9 cM和1.6 cM。     

Tuning of electronic properties of one-dimensional cyano-bridged Cu-Ni, Cu-Pd, and Cu-Pt bimetallic assemblies by stereochemistry of ligands

Preparations, XPS and electronic spectroscopy, and magnetism of seven new one-dimensional cyano-bridged coordination polymers, chiral [Cu(RR-chxn)₂][Pd(CN)₄] · 2H₂O (1), [Cu(trans-chxn)₂][M(CN)₄] · 2H₂O (2, 4, and 6 for M = Pd, Ni, and Pt), and [Cu(cis-chxn)₂][M(CN)₄] · 2H₂O (3, 5, and 7 for M = Pd, Ni, and Pt) (RR-chxn = cyclohexane-(1R,2R)-diamine, trans-chxn = racemic trans-cyclohexane-(1,2)-diamine, and cis-chxn = racemic cis-cyclohexane-(1,2)-diamine) have been reported in view of tuning of their electronic properties by stereochemistry of chxn ligands and metal-substitution. Comparison of Cu 2p_1/2 and 2p_3/2 peaks of XPS and broad d-d bands around 18 000 cm⁻¹ of electronic spectra are described systematically for 1-7. Variable-temperature magnetic measurement shows that complexes 1-7 indicate weak antiferromagnetic interactions via cyano-bridges. Because of semi-coordination coupled with pseudo Jahn-Teller elongation and electrostatic interaction for 1, the axial Cu-N coordination bond distances of 2.330(7) and 3.092(8) Å are considerably longer than those of equatorial ones in the range from 2.016(6) to 2.030(6) Å. The former bond distances of 1 are intermediate values among the related Ni (2.324(6) and 3.120(8) Å) and Pt (2.34(1) and 3.09(1) Å) complexes.     

多马胺能药物对鲇鱼促性腺激素（GtH）分泌活动的影响

以珠江流域鲇鱼（silurus asotus)为实验材料,研究了多巴胺（DA）能药物（DA及其D－2型受体拮抗物 ,DOM）对鲇鱼促性腺激素（GtH)释放的影响,结果表明,在性腺发育的各个时期,单独注射DOM（5ug/g)均不能显著提高鲇鱼血液基础GtH水平,当DOM与LHRH－A联合注射时能显著增强LHRH－A刺激GtH释放的作用;DA只能抑制GnRH诱导的GtH释放,对基础GtH释放无抑制作用,这种生殖内分泌调节方式与鲇形目的革胡子鲇（Clarias gariepinus)和大鳍Hu（Mystus macropterus)相似,而与鲤形目的鲁科（Cyrpindiae)鱼类不同。     

Influence of Fluoride on Rat Kidney Antioxidant System: Effects of Methionine and Vitamin E

The aim of the study has been to determine and compare the influence upon the kidney antioxidative system, exercised by administration of vitamin E, and vitamin E in combination with methionine, under conditions of oxidative stress induced by sodium fluoride. The experiment was carried out on Wistar FL rats (adult males) that, for 35 days, were administered water, NaF, NaF with vitamin E, or vitamin E with methionine (doses: 10 mg NaF/kg of body mass/24 h, 3 mg vitamin E per 10 μl per rat for 24 h, 2 mg methionine per rat for 24 h). The influence of administered sodium fluoride and antioxidants upon the antioxidative system in kidney was examined by analyzing the concentration of malondialdehyde (MDA) and the activity of the most important antioxidative enzymes (SOD, total and both its isoenzymes, GPX, GST, GR, and CAT). The studies carried out confirmed the disadvantageous effect of the administered dose of NaF upon the antixodiative system in rats (increase in the concentration MDA, decrease activity of all antioxidative enzymes). The administration of vitamin E increased the activity of studied enzymes with the exception of glutathione reductase GR; it also reduced the procesess of lipid peroxidation. It has been found that combined doses of vitamin E and methionine were most effective in inhibiting lipid peroxidation processes. The results confirmed the antioxidative properties of methionine.     

Reorientation of Microfibrils and Microtubules at the Outer Epidermal Wall of Maize Coleoptiles During Auxin-Mediated Growth

Auxin-mediated elongation growth of isolated subapical coleoptile segments of maize (Zea mays L.) is controlled by the extensibility of the outer cell wall of the outer epidermis (Kutschera et al., 1987). Here we investigate the hypothesis that auxin controls the extensibility of this wall by changing the orientation of newly deposited microfibrils through a corresponding change in the orientation of cortical microtubules. On the basis of electron micrographs it is shown that cessation of growth after removal of the endogenous source of auxin is correlated with a relative increase of longitudinally orientated microfibrils and microtubules at the inner wall surface. Conversely, reinduction of growth by exogenous auxin is correlated with a relative increase of transversely orientated microfibrils and microtubules at the inner wall surface. These changes can be detected 30–60 min after the removal and addition of auxin, respectively. The functional significance of directional changes of newly desposited wall microfibrils for the control of elongation growth is discussed.     

Combination of dihydromyricetin and ondansetron strengthens antiproliferative efficiency of adriamycin in K562/ADR through downregulation of SORCIN: A new strategy of inhibiting P-glycoprotein

Though the advancement of chemotherapy drugs alleviates the progress of cancer, long-term therapy with anticancer agents gradually leads to acquired multidrug resistance (MDR), which limits the survival outcomes in patients. It was shown that dihydromyricetin (DMY) could partly reverse MDR by suppressing P-glycoprotein (P-gp) and soluble resistance-related calcium-binding protein (SORCIN) independently. To reverse MDR more effectively, a new strategy was raised, that is, circumventing MDR by the coadministration of DMY and ondansetron (OND), a common antiemetic drug, during cancer chemotherapy. Meanwhile, the interior relation between P-gp and SORCIN was also revealed. The combination of DMY and OND strongly enhanced antiproliferative efficiency of adriamycin (ADR) because of the increasing accumulation of ADR in K562/ADR-resistant cell line. DMY could downregulate the expression of SORCIN and P-gp via the ERK/Akt pathways, whereas OND could not. In addition, it was proved that SORCIN suppressed ERK and Akt to inhibit P-gp by the silence of SORCIN, however, not vice versa. Finally, the combination of DMY, OND, and ADR led to G2/M cell cycle arrest and apoptosis via resuming P53 function and restraining relevant proteins expression. These fundamental findings provided a promising approach for further treatment of MDR.     

Structure and function of S-adenosylhomocysteine hydrolase

In mammals, S-adenosylhomocysteine hydrolase (AdoHcyase) is the only known enzyme to catalyze the breakdown of S-adenosylhomocysteine (AdoHcy) to homocysteine and adenosine. AdoHcy is the product of all adenosylmethionine (AdoMet)-dependent biological transmethylations. These reactions have a wide range of products, and are common in all facets of biometabolism. As a product inhibitor, elevated levels of AdoHcy suppress AdoMet-dependent transmethylations. Thus, AdoHcyase is a regulator of biological transmethylation in general. The three-dimensional structure of AdoHcyase complexed with reduced nicotinamide adenine dinucleotide phosphate (NADH) and the inhibitor (1′R, 2′S, 3′R)-9-(2′,3′-dihyroxycyclopenten-1-yl)adenine (DHCeA) was solved by a combination of the crystallographic direct methods program, SnB, to determine the selenium atom substructure and by treating the multiwavelength anomalous diffraction data as a special case of multiple isomorphous replacement. The enzyme architecture resembles that observed for NAD-dependent dehydrogenases, with the catalytic domain and the cofactor binding domain each containing a modified Rossmann fold. The two domains form a deep active site cleft containing the cofactor and bound inhibitor molecule. A comparison of the inhibitor complex of the human enzyme and the structure of the rat enzyme, solved without inhibitor, suggests that a 17° rigid body movement of the catalytic domain occurs upon inhibitor/substrate binding.     

Evolution of different oligomeric glycyl-tRNA synthetases

There are two oligomeric types of glycyl-tRNA synthetases (GlyRSs) in genome, the alpha2beta2 tetramer and alpha2 dimer. Here, we showed that the anticodon-binding domains (ABDs) of dimeric and tetrameric GlyRSs are non-homologous, although their catalytic central domains (CCDs) are homologous. The dimeric GlyRS_ABD is fused to the C-terminal of CCD in alpha-subunit, but the tetrameric GlyRS_ABD is to the C-terminal in beta-subunit during evolution. Generally, one species only contains one oligomeric type of GlyRS, but the both oligomeric GlyRSs with the multiple homologous domains can be observed in Magnetospirillum magnetotacticum genome, nevertheless, these homologous domains are probably from different genomes.     

Plasmodium berghei: lack of antimalarial activity of an analogue of folate precursor, 2,4-diamino-6-hydroxymethylpteridine in a mouse model

It was earlier hypothesized that the malarial parasite may convert precursors of folate analogues to synthesize de novo inhibitors toxic to itself, but not to the mammalian cell. It was suggested that one such analogue, 2,4-diamino-6-hydroxymethylpteridine (DAP) may be converted to aminopterin (AMP), a known dihydrofolate reductase inhibitor. In the present study, we evaluated the ability of DAP to inhibit proliferation of Plasmodium berghei NK65 in mice, with(out) folinic acid rescue. Cumulative dosages of DAP ranging from 0.1 to 20 mg/kg bw. administered either orally or intraperitoneally showed no suppression of parasite growth, or gave mild activities that were not statistically significant (P > 0.05). Our findings do not seem to support the hypothesis of selective de novo metabolism of DAP to AMP by the malarial parasite.     

围隔藻类水华演替过程中二甲基硫化物的含量动态

于2005年6月至7月,研究了海洋围隔不同藻类水华演替过程中二甲基硫化物的含量动态,并考察了相关环境参数对二甲基硫化物含量的影响。2个围隔实验组均出现未知藻水华-硅藻水华-甲藻水华的演替过程,这3次不同藻类水华分别对应了二甲基硫化物含量的3次高峰,表明藻类水华对二甲基硫化物含量有重要贡献。不同藻类水华的贡献有较大差异,甲藻水华的贡献最大,硅藻次之,未知藻类水华的贡献最小。实验结果还表明PO4^3-、NO2^-和NH4^＋主要通过影响藻类生长状态,进而影响DMSP和DMSO的含量;NO2^-和NH4^＋亦可能通过调节DMSP和DMSO在藻细胞内的生理功能,影响DMSP和DMSO的含量;PO4^3-、NO2^-和NH4^＋与DMS含量无显著相关。     

Land,livestock, and livelihoods: Changing dynamics of gender,caste, and ethnicity in a Nepalese Village

Over the past 10 years, Ghusel VDC, Lalitpur District has moved from primarily subsistence agriculture into the wider cash economy aided by the Small Farmers' Development Program (SFDP), which provides credit to farmers mainly for the purchase of buffalo for milk production, and by the National Dairy Corporation, which supports local dairy cooperatives. Analysis reveals that buffalo-keeping and milk sales are increasing the well-being of many households, while at the same time creating new inequalities in gender roles and responsibilities, greater inequities between Brahmin and Tamang residents in Ghusel, and placing pressures on the ecosystem for increased supplies of fodder and fuelwood. Evidence suggests that there is critical, need for attention to the social, and particularly gender-based, implications of maintaining livestock for milk sales and to the ecological underpinnings of this livelihood system.