硫营养对小麦籽粒淀粉合成及相关酶活性的影响

在田间条件下,研究了施硫对小麦籽粒淀粉合成及相关酶活性的影响.结果表明:在0～20 cm土层土壤有效硫含量为5.84 mg/kg的地块上施硫不仅提高了小麦籽粒中蔗糖的含量,而且催化蔗糖降解代谢的蔗糖合成酶(SS)活性提高,利于籽粒蔗糖的降解.施硫显著提高了灌浆期间籽粒可溶性淀粉合成酶(SSS)活性,并使腺苷二磷酸葡萄糖焦磷酸化酶(ADPGPPase)和束缚态淀粉合成酶(GBSS)活性在灌浆中、后期维持在较高水平,对直链和支链淀粉的合成都起促进作用, 使总淀粉积累增加,千粒重提高,产量增加.     

氮、磷、钾对豫麦50旗叶蔗糖和籽粒淀粉积累的影响

以豫麦50为对象,探讨了氮、磷、钾对小麦旗叶中蔗糖的积累及相关酶活性以及籽粒中淀粉含量和组分的影响.结果表明,施氮可以增加灌浆前期旗叶中的糖含量,施钾则提高了灌浆后期旗叶中的糖含量,而施磷则对旗叶中的糖含量影响不大.施氮、磷、钾均能增加蔗糖合成酶活性,但它们的作用时间不同：施氮活性增加在籽粒灌浆中期,施磷在灌浆前期,而施钾在灌浆前、中期.但氮亦可增加花后24 d的磷酸蔗糖合成酶活性,施磷增加了灌浆前、中期磷酸蔗糖合成酶活性,施钾则增加了灌浆后期旗叶磷酸蔗糖酶活性.施氮、磷、钾都提高了籽粒中总糖含量,增加籽粒中淀粉含量,其中施钾效果最为明显.施磷提高籽粒中直链淀粉的积累,而施钾则显著提高了籽粒中支链淀粉的含量.     

结实期土壤水分亏缺影响水稻籽粒灌浆的生理原因

通过分析结实期土壤水分亏缺对水稻(Oryza sativa)籽粒中蔗糖向淀粉合成的生理代谢中关键酶活性及籽粒灌浆的调节作用, 探讨土壤水分亏缺影响水稻籽粒灌浆的生理机制。结果表明, 适度土壤水分亏缺诱导了灌浆高峰期(花后15-20天)水稻籽粒中蔗糖合成酶、腺苷二磷酶葡萄糖焦磷酸化酶、可溶性淀粉合成酶及淀粉分支酶活性的增加, 提高了籽粒灌浆中前期(花后10-20天)籽粒中淀粉积累速率和籽粒灌浆速率。但在灌浆后期(花后20-30天)籽粒中, 上述关键酶活性下降较快, 籽粒活跃灌浆期明显缩短, 灌浆前中期灌浆速率的增加不能完全补偿灌浆期缩短带来的同化物积累损失, 导致水分亏缺处理水稻籽粒充实不良, 结实率、籽粒重和产量显著降低。研究认为, 灌浆期土壤水分亏缺引起的灌浆后期籽粒中蔗糖向淀粉合成代谢中一些关键酶活性快速下降和籽粒内容物的供应不足是籽粒淀粉积累总量减少、粒重降低的主要生理原因。     

钾对小麦旗叶蔗糖和籽粒淀粉积累的影响

 利用冬小麦品种‘鲁麦22’(Triticum aestivum cv. `Lumai 22’)在大田条件下研究了钾素对小麦旗叶蔗糖和籽粒淀粉积累及其有关酶活性的影响。结果表明,钾素有利于提高旗叶光合速率,增强开花后旗叶磷酸蔗糖合成酶活性,提高旗叶中蔗糖的含量;从而提高了灌浆期间籽粒中蔗糖的供应,增强了籽粒中蔗糖合成酶和腺苷二磷酸葡萄糖焦磷酸化酶的活性,加速了淀粉积累速率,提高了粒重和产量。     

玉米灌浆期水分差异供应对籽粒淀粉积累及其酶活性的影响

利用普通玉米(Zay mays)‘掖单22’和高油玉米‘高油115’,研究了灌浆期水分差异供应对籽粒淀粉及其组分积累、相关酶活性动态变化的影响。结果表明,两种类型玉米淀粉积累和酶活性动态变化趋势基本一致,但对水分的反应有差异。缺水提高了‘掖单22’籽粒中淀粉、支链淀粉含量,而直链淀粉含量下降,‘高油115’则是籽粒中的淀粉含量、支链淀粉和直链淀粉含量提高;充分供水使淀粉及其组分产量提高;叶片中蔗糖合成酶(SS)、磷酸蔗糖合成酶(SPS)活性随水分供应水平而提高,尤其在授粉后10~30 d增幅更加明显。充分供水明显提高籽粒中腺苷二磷酸葡萄糖焦磷酸化酶(ADPG-PPase)、尿苷二磷酸葡萄糖焦磷酸化酶(UDPG-PPase)、可溶性淀粉合成酶(SSS)和淀粉粒结合淀粉合成酶(GBSS)活性,缺水使籽粒中酶活性下降较早且迅速;SPS、ADPG-PPase、SSS酶活性对缺水反应比较敏感。     

He-Ne激光对UV-B辐射小麦幼苗糖代谢的影响

分别采用5 mW·mm-2 He-Ne激光辐照、10.08 kJ·m-2·d-1 增强UV-B辐射及二者组合对"晋麦8号"小麦幼苗进行处理,测定各处理幼苗叶片可溶性糖、还原性糖、蔗糖合成酶(SS)、蔗糖磷酸合成酶(SPS) 以及α,β-淀粉酶的变化.研究分析He-Ne激光对增强UV-B辐射引起小麦损伤的修复效应.结果表明:He-Ne激光辐照可使UV-B辐射后小麦幼苗可溶性糖含量升高,还原性糖含量降低,SS,SPS活力降低,α,β-淀粉酶活力升高.该结果同时表明可溶性糖、还原性糖、SS、SPS、α,β-淀粉酶的变化同小麦幼苗损伤修复的能力相关,一定剂量的He-Ne激光辐照可部分修复增强UV-B对小麦幼苗糖代谢的辐射损伤.     

小麦籽粒灌浆期冠层温度分异动态及其与源库活性的关系

选用18个小麦品种为材料,从开花期到乳熟末期,对品种间冠层温度进行比较,并对冠层温度与旗叶源活性指标(丙二醛含量、蔗糖磷酸合成酶活性、净光合速率、叶绿素含量、单茎有效绿叶数、顶三叶绿叶面积比率)和库活性指标(籽粒蔗糖合成酶活性、ADPG焦磷酸化酶活性、可溶性蛋白含量、籽粒淀粉积累速率)进行相关分析.结果表明:小麦品种间冠层温度在各生育时期均有显著性差异,且随灌浆进程的推进差异程度越来越大;从乳熟初期到乳熟末期,冠层温度与各源活性指标的相关系数均有增加的趋势,并在乳熟后期和末期均达到极显著水平;冠层温度与各库活性指标的相关系数在乳熟末期均达到显著水平.研究发现,小麦籽粒灌浆期品种间冠层温度差异随生育期推进而愈加显著,冠层温度与源库活性的关系以乳熟后期和末期最密切.     

糖代谢相关酶在灵武长枣叶片和果柄糖积累中的作用

以不同发育时期灵武长枣为试材,测定果实生长发育过程中叶片、果柄可溶性糖含量及蔗糖代谢相关酶活性的变化,探讨果实生长发育过程中叶片、果柄糖的积累与蔗糖代谢相关酶活性的关系。结果表明:(1)灵武长枣叶片、果柄均主要以积累蔗糖为主,叶片、果柄中葡萄糖和果糖含量的变化平缓且随果实发育略有上升,蔗糖含量则呈先下降后迅速上升的趋势,且蔗糖含量始终高于葡萄糖和果糖的含量。(2)在果实的整个发育期,叶片和果柄的酸性转化酶(AI)活性均远高于中性转化酶(NI),AI在前期升高后变化较平稳,而蔗糖合成酶(SS)和蔗糖磷酸合成酶(SPS)活性的变化各不相同。(3)SS分解方向酶活性(SSd)对叶片和果柄蔗糖的积累具有重要的调节作用。研究认为,蔗糖合成酶分解方向酶活性(SSd)对灵武长枣叶片和果柄蔗糖的积累起主要的调控作用。     

铵态氮和氨基酸态氮配施对甜菜生长特性及碳代谢的影响

采用甜菜(Beta vulgaris L.)为试验材料,在盆栽条件下,施以无机氮(铵态氮)和有机氮(氨基酸态氮)不同比例(有机氮分别占总施氮量33%和67%)配施,分析了甜菜不同生育阶段叶片叶绿素含量、块根和茎叶全氮含量、干物质、叶片蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS)、转化酶、可溶性糖、蔗糖、还原糖以及甜菜产量、含糖率和产糖量的变化规律,探讨了不同氮素形态比例对甜菜生长特性和碳代谢的影响。结果表明,无机氮(铵态氮)和有机态氮(氨基酸态氮)不同比例配施在不同的生育时期,对甜菜的生长特性和碳代谢的影响不同。不同比例有机态氮的处理可以增加甜菜地上和地下的干物质积累,在收获期之前,有机氮(占总施氮量67%)处理明显促进甜菜生长,到收获期之后有机氮(占总施氮量33%)处理的甜菜干物质量积累最多;在全生育期,不同有机氮(占总施氮量33%和67%)处理均增加甜菜叶片的叶绿素含量;在糖分增长期之后,有机态氮处理的甜菜块根和叶片氮积累量均大于无机氮处理,说明氨基酸态氮也可以成为良好氮源;不同比例有机态氮的处理可以在甜菜不同生育期提高甜菜叶片蔗糖磷酸合成酶(SPS)、蔗糖合成酶(SS)活性和转化酶活力;随有机态氮比例的增加,块根中可溶性糖、蔗糖含量明显增加,还原糖含量降低,对块根蔗糖的积累有促进作用;块根中含糖率有机态氮比例的增加而增加,但块根产量和产糖量以有机态氮占总施氮量33%时最高。     

龙柚果肉糖积累与蔗糖代谢相关酶活性的研究

本文探讨龙柚果实发育过程中果肉糖积累与蔗糖代谢相关酶活性的变化。结果表明,在龙柚果实发育过程中,3种可溶性糖含量同步上升,在果实膨大期和成熟期,以蔗糖积累为主。在龙柚糖积累过程中,蔗糖合成酶(SS)和蔗糖磷酸合成酶(SPS)活性较高;而蔗糖中性转化酶(NI)活性则随着蔗糖的积累而降低。     

白蚁与动物及微生物的共生类型及其机制

综述了白蚁螱客的主要种类、共生关系及相关机制的研究进展。白蚁螱客中,已报道的动物种类达170种。在与动物的共生关系中存在偏利共生（宾主共栖和异种共栖）、互利共生和无关共生三种;在与微生物的共生关系中,存在与内生菌（原生动物、细菌、真菌和放线菌）和外生菌（蚁巢伞菌等）间的互利关系。指出了白蚁与螱客研究中存在的问题,给出了解决方案,并提出了今后可能的研究热点或方向,为白蚁的综合利用（如纤维素酶）及今后研究物种间的协同进化提供了基础资料。     

New amino-dithiaphospholanes and phosphoramidodithioites and their rhodium and iridium complexes

New sulfur derivatives of phosphoramidite ligands were synthesized and the impact of the sulfur unit on the spectroscopic properties of their rhodium and iridium complexes was investigated. The new ligands Bn₂NPSCH₂CH₂S^a(P-S^a) (Bn = benzyl, 4), Bn₂NPSCHCHS^a(CH₂)₃C^aH₂(P-S^a)(C^a-S^a) (6) and Bn₂NP(4-XC₆H₄OMe)₂ (X = S, 7a; X = O, 7b) were converted to the rhodium and iridium complexes trans-[Rh(CO)Cl(L)₂] (L = 4, 6, 7), [RhCl(COD)(L)] (L = 4, 6, 7), [IrCl(COD)(7a)] and [IrCl₂Cp∗(6)]. For comparison, some phosphoramidite complexes of these formulations also were synthesized. The new metal complexes were spectroscopically analyzed. For the carbonyl complexes, the ν_CO IR stretching frequencies were lower than for the corresponding phosphite and phosphoramidite ligands. The ¹J_PRh coupling constants for the rhodium complexes with the new ligands were also smaller than for the respective phosphoramidite and phosphite complexes. Finally, the ¹J_PSe coupling constants of the selenides of the new ligands were lower than those of the phosphoramidite ligands but higher than for PPh₃. The spectroscopic data reveal that the new thio ligands 4, 6 and 7a are more electron donating than phosphites and phosphoramidites but less electron donating than PPh₃.     

Astrocytes and Synaptosomes Transport and Metabolize Lactate and Acetate Differently

Astrocytes transport the monocarboxylate acetate, but synaptosomes do not. The reason for this is unknown, because both preparations express monocarboxylate transporters (MCT). The transport and metabolism of lactate, another monocarboxylate, was examined in these two preparations, and the results were compared to those for acetate. Lactate transport is more rapid in astrocytes than in synaptosomes, but of lower affinity (Kms of 17 and 4 mM, respectively). Lactate (0.2 mM) is metabolized to CO2 more rapidly in synaptosomes than in astrocytes (rates of 0.37 and 0.07 nmol x mg protein(-1) x min(-1), respectively). The reason for this is unclear, but cellular differences in lactate dehydrogenase isotype expression may be involved. Acetate is metabolized to CO2 more rapidly in astrocytes than in synaptosomes (rates of 0.43 and 0.02 nmol x mg protein(-1) x min(-1), respectively). This is likely due to cellular differences in the expression of monocarboxylate transporter subtypes.     

Rapporteur report: Basics and technology and metrology and standards

The first and second sessions of the Workshop focussed on the basics of ultrasound and infrasound, their applications in both industry and medicine, and metrology and protection standards for ultrasound applications.     

Relative and combined effects of ethanol and protein deficiency on strontium and barium bone content and fecal and urinary excretion

To elucidate accumulation of minerals in human iliac arteries with aging, the content of minerals was analyzed by inductively coupled plasma atomic emission spectrometry. Bilateral common, internal, and external iliac arteries of 16 men and 8 women, ranging ages from 65 to 93 yr, were examined. It was found that an extremely high accumulation of calcium and phosphorus occurred in the common iliac artery at old age, being higher than that of the internal and external iliac arteries. It should be noted that the accumulation of calcium and phosphorus is the highest in the common iliac artery among the human arteries examined to date. Regarding sexual differences, the content of calcium and phosphorus in the common and internal iliac arteries was higher in women than in men, whereas their content in the external iliac artery was lower in women than in men.     

Prostaglandin and thromboxane production by human and guinea-pig macrophages and leucocytes

The ability of partially purified human and guinea-pig haematogenous cell populations, when cultured in vitro, to metabolise arachidonic acid (AA) has been studied. Supernatants from 24 hour cell culture have been subjected to analysis for products of AA metabolism by gas chromatography with electron-capture detection.The cell types studied were human peripheral blood monocytes (both glass adherent and non-adherent), neutrophils, eosinophils and leukemic leucocytes; thoracic duct lymphocytes and lung alveolar macrophages. From the guinea-pig, induced and non-induced macrophage or neutrophil enriched peritoneal exudate populations, lymph node cells, peritoneal eosinophils and peripheral blood platelets were examined. Supernatants were assayed for the presence of PGE₂, PGD₂, PGF_2α, TXB₂ and 6-keto-PGF_1α. In all types studied PGE₂ and TXB₂ were the major products formed. The identification of PGE₂ and TXB₂ was confirmed by GC/MS with multiple ion monitoring.The results have been compared with other reports and their possible significance discussed in relation to the proposed role of prostaglandins as mediators and modulators in immunopathology.     

Chemokines and cytokines: axis and allies in asthma and allergy

Allergic asthma can be precipitated by many factors. For the atopic person, fungus, pollen, dust mites, cockroach antigens, and diesel exhaust are all agents that may trigger an allergic attack. Cytokines and chemokines are integral mediators of fungal asthma. From the earliest time points, they recruit and activate the cells required for the clearance of fungus as well as being critical factors involved in the immunopathology of this disease. In the final analysis, it is clear that these mediators can act to the benefit or the detriment of the host.     

Oxidation and nitration of ribonuclease and lysozyme by peroxynitrite and myeloperoxidase

In spite of the many studies on protein modifications by reactive species, knowledge about the products resulting from the oxidation of protein-aromatic residues, including protein-derived radicals and their stable products, remains limited. Here, we compared the oxidative modifications promoted by peroxynitrite and myeloperoxidase/hydrogen peroxide/nitrite in two model proteins, ribonuclease (6Tyr) and lysozyme (3Tyr/6Trp). The formation of protein-derived radicals and products was higher at pH 5.4 and 7.4 for myeloperoxidase and peroxynitrite, respectively. The main product was 3-nitro-Tyr for both proteins and oxidants. Lysozyme rendered similar yields of nitro-Trp, particularly when oxidized by peroxynitrite. Hydroxylated and dimerized products of Trp and Tyr were also produced, but in lower yields. Localization of the main modified residues indicates that peroxynitrite decomposes to radicals within the proteins behaving less specifically than myeloperoxidase. Nitrogen dioxide is emphasized as an important protein modifier.