异爪蝗属及雏蝗属部分种类染色体核型及C带带型分析研究(直翅目,蝗总科)

分析研究异爪蝗属Euchorthippus Tarb.2种和雏蝗属Chorthippus Fieb.5种的染色体核型及C带带型.结果表明,2个属在染色体数目、染色体组式、异染色质含量等方面都有明显的差异.属下种间在染色体数目、染色体组式、性别决定机制、着丝粒C带等方面有相同的特征,在染色体相对长度、异染色质含量等方面有差异.     

L-肉碱的生理功能及其应用研究进展

L-肉碱是一种季铵化合物,在人类和动物的脂肪酸β-氧化过程中发挥重要作用.L-肉碱极强的生物可利用性使其倍受关注.然而在诸如婴儿、孕妇、血液透析病患者及一些慢性疾病等情况下L-内碱极易缺乏.因此目前L-肉碱被广泛应用于医药、食品及饲料添加荆等方面.本文综述了L-肉碱对婴儿、孕妇、中老年人、运动员、肥胖患者等的营养、保健功能及其在肾衰竭、和透析相关的并发症、心血管疾病、男科不育症、癌症、糖尿病、高血脂症等病症治疗中的应用.随着L-肉碱系列产品研究成为热点,其在保健品、医药及化妆品工业的应用将具有更美好的前景.     

表达谱基因芯片

表达谱基因芯片具有高通量、缩微、多参数、平行化等优点.在功能基因组学研究中正发挥越来越重要的作用.就其原理、应用、存在问题及解决策略等进行了综述.     

热休克蛋白gp96在恶性肿瘤中的研究进展

热休克蛋白90B1又称为糖蛋白96 (gp96). gp96属于热休克蛋白90家族,是一种高度保守且普遍存在的糖蛋白.作为一种内质网蛋白,gp96在维持内质网稳态、内质网应激、钙稳态等方面起着重要的调控作用,这些调控网络在肿瘤的发生发展过程中起着重要的作用. gp96作为分子伴侣在稳定和激活客户蛋白等方面有众多报道,其中包括HER2、整合素和Toll样受体等多个客户蛋白.大量研究表明,gp96在肝癌、乳腺癌、胃癌等不同类型的肿瘤中高表达,并在肿瘤的生长、侵袭和转移等方面起着重要的作用.本文从gp96的基本结构和功能及其在肿瘤发生发展中的作用等方面进行综述,并着重阐述细胞膜gp96相关的研究进展.最后,重点介绍基于胞膜gp96结构所设计的选择性小分子抑制剂、抗体和多肽等药物在肿瘤靶向治疗中的潜在应用.     

PAK5在凋亡级联反应中的调节作用

PAK5为PAKs家族中新近发现的成员. PAKs是一类通过与Rac和Cdc42结合而激活的高度保守的蛋白酶.PAKs在细胞骨架、神经生长、激素信号传导、基因转录等生理活动中起着重要的调控作用. PAK5在大脑组织中高度表达,在细胞中定位于线粒体. PAK5 与神经生长、增强微管的稳定性以及阻止细胞凋亡等活动密切相关.本文就PAK5的结构、表达部位和功能以及其在调控凋亡级联反应中的作用等方面做了简要综述.     

miRNAs的表达调控机制

microRNAs(miRNAs)是一类在转录后基因调控中发挥功能的非编码小RNAs,在发育、生长和分化等过程中发挥重要作用.至今已经在动物、植物和微生物等不同生物体中鉴定出来数千种miRNAs. miRNAs可以通过降解mRNA或抑制蛋白翻译的方式调节特异基因表达.生物体内约30%的基因都受miRNAs的调节.miRNAs的表达与功能受到转录因子、表观遗传学、多核苷酸多态性及其RNA编辑等多种因素的调节.此外,特异miRNA基因敲除的成功为研究miRNAs功能提供了有力的实验模型.     

湖泊生态系统动力学模型研究进展

从系统分析在湖泊生态系统动力学研究中的作用出发,对湖泊生态系统的动力学建模过程、方法和软件等进行了总结.在此基础上,综述了国内外湖泊生态系统动力学模型的发展.从1960年代至今,湖泊生态系统动力学模型从简单的零维模型发展到复杂的水质水动力学生态综合模型和生态结构动力学模型,如LakeWeb模型.中国的湖泊生态系统动力学模型研究始于20世纪80年代,主要集中在滇池、太湖、东湖和巢湖等富营养化严重的湖泊以及其他水体.目前,已经开发一些软件用于湖泊生态系统动力学模拟,主要有CEQUALICM、WASP、AQUATOX、PAMOLARE、CAEDYM等,以及用来模拟湖泊能流的软件ECOPATH.湖泊生态系统动力学模型还在监测、数据共享和模型结构、参数选取和不确定性分析等方面存在不足,需在今后的研究中加以改进.     

miR-145与肿瘤相关研究及其临床应用

microRNAs(miRs)是一类长约22核苷酸的内源性非编码单链RNA分子,对生长发育、细胞增殖、凋亡乃至肿瘤发生发展等生命过程具有重要作用.其中,miR-145是研究最多的miRs之一,研究发现其在多种肿瘤组织中表达下调.通过与多种靶分子,如OCT4、MUC1等相互作用,miR-145可影响肿瘤细胞的增殖、转移及凋亡等过程.在临床应用方面,多项研究发现,miR-145表达水平与肿瘤患者的诊断及预后具有良好的相关性.此外,其表达水平还与卵巢癌等多种肿瘤的化疗耐药性相关.本文就miR-145对肿瘤的发生发展的作用及影响,以及在临床上诊断、治疗和预后等方面的应用前景做一综述.     

白藜芦醇代谢物的研究进展

白藜芦醇是一些植物在受到生物和非生物胁迫时产生的一种植物抗毒素.它在植物体内会迅速被代谢而生产紫檀芪、云杉新苷、viniferins等代谢物.这些代谢物与白藜芦醇一样具有抗菌、消炎、抗血小板凝集、防止细胞癌变等一系列的生物活性,且有些代谢物的选择性、稳定性远远大于白藜芦醇.本文对白藜芦醇代谢物中几种主要代谢物的合成途径、生物活性、代谢调控、检测方法等进行了综述.     

PDGF 及其受体介导的信号转导与妇科肿瘤关系研究进展

血小板衍生生长因子(Platelet-Derived Growth Factor,PDGF)是一类与生长、发育、癌症发生等密切相关的细胞因子,由多种细胞分泌产生,具有广泛的生物学活性,涉及多种疾病.目前关于PDGF分子结构、表达调控、生物学活性等已有较为深入的研究,本文在介绍上述研究成果的同,对PDGF在妇科肿瘤中的病理生理作用进一步综合分析.PDGF参与卵泡的发生;PDGF与子宫肌瘤、宫颈、卵巢癌等疾病相关联.PDGF在妇科肿瘤的发生、发展中起着重要的作用.     

Comparison of application methods for suppressing the pecan weevil (Coleoptera: Curculionidae) with Beauveria bassiana under field conditions

The pecan weevil, Curculio caryae (Horn), is a key pest of pecans. The entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin is pathogenic to C. caryae. One approach to managing C. caryae may be application of B. bassiana directed toward adult weevils as they emerge from the soil to attack nuts in the tree canopy. Our objective was to compare different application methods for suppression of C. caryae adults. Treatments included direct application of B. bassiana (GHA strain) to soil under the tree canopy, soil application followed by cultivation, soil application in conjunction with a cover crop (Sudan grass), direct application to the tree trunk, and application to the trunk with an UV radiation-protecting adjuvant. The study was conducted in a pecan orchard in Byron, GA, in 2005 and 2006. Naturally emerging C. caryae adults, caught after crawling to the trunk, were transported to the laboratory to determine percentage mortality and signs of mycosis. When averaged over the 15-d sampling period, weevil mortality and signs of mycosis were greater in all treatments than in the nontreated control in 2005 and 2006; >75% average mortality was observed with the trunk application both years and in the trunk application with UV protection in 2005. Results indicated trunk applications can produce superior efficacy relative to ground application, particularly if the ground application is followed by cultivation. Efficacy in the cover crop treatment, however, did not differ from other application approaches. Future research should focus on elucidating the causes for treatment differences we observed and the extent to which B. bassiana-induced C. caryae mortality reduces crop damage.     

Costs of emission-reducing manure application

Favourable economics of handling and application of manure are of fundamental importance to encourage the implementation of emission-reducing application techniques. The economics of manure application depend on the costs of the equipment and the time to carry out the field operation. In this study the costs of application techniques designed to reduce ammonia losses were assessed and compared with the costs of conventional broadcast spreading across a range of farm characteristics. A model was developed to calculate the costs and time requirements of manure application. Data on factors affecting the costs were used from different countries in Europe. The calculations showed that for a range of farm characteristics with a manure production of 1000-3000 m(3)y(-1), the costs of manure application by trailing hose, trailing foot, shallow injector and arable land injector were approximately 2 m(-3) higher than for broadcast spreading. The cost difference between broadcast spreading and the other application techniques decreased with farm size. The average additional costs of manure application by a trailing foot or a shallow injector decreased by 15% on small extensive farms to more than 50% on intensive farms, when the fertiliser value of the nitrogen was taken into account. The field application itself took less than 50% of the operating time in the process of the manure handling and application. With an increasing application rate, the relative contribution of the time for field application decreased.     

Effects of timing of sulphur application on yield,S-uptake and quality of barley

The effect of N application (four levels) and time of S application (from sowing to the middle of heading) on yield and quality of spring barley (Hordeum vulgare L.) was investigated in pot experiments. Also, a no S treatment was included. At the two lowest N levels grain yield was unaffected by S application, but with increasing N level there was an increasing yield response to S application. Deficiency symptoms were observed from the beginning of tillering onwards at the highest levels of N application. Sulphur applied when the flag leaf was first visible eliminated the symptoms and prevented yield reductions. Mineralised soil organic S fulfilled the S requirements of plants grown at the lowest N rate and sustained plants at the higher N levels until the late S application. The effectiveness of a late S application may be lower under field conditions because of poor mobility of S in the soil under dry conditions. Late S application caused the percentage of fertiliser-derived S in grain to decrease at all N levels. Without S application the concentrations of the S-containing amino acids cysteine and methionine decreased on both dry weight and protein basis, especially at the highest N levels. Late S application even at the middle of heading prevented this reduction of S-containing amino acids. This indicates that adequate protein quality may be achieved by delayed S application despite yield reductions.     

基于APSIM模型的旱地春小麦产量对施氮量和施氮深度的响应模拟

氮是限制黄土高原旱农区作物水分生产潜力提升的重要因素,而氮肥适度深施是旱地作物提效增产的有效措施.本研究利用甘肃省陇中地区1990-2020年气象观测数据,基于APSIM模型模拟了不同施氮量和施氮深度的春小麦产量,以期为优化陇中旱农区小麦施肥策略提供理论依据.结果表明:模型模拟的春小麦产量、生物量和生育期0～200 c...     

Ultrastructural changes in the neural tube of 10-day-old mouse embryos exposed to colchicine and hydroxyurea

The ultrastructural changes in the neural tube of 10-day-old mouse embryos were investigated between 1.5 hr and 4 hr after application of either 1 mg/kg colchicine (Col) or 500 mg/kg hydroxyurea (HU) or simultaneous application of both substances. During the investigated period, the shape of the nuclei of the neuroepithelial cells had changed from elongated to round after Col application. The chromatin in the nuclei was condensed and arranged in clusters. A breakdown of polysomes into ribosomes and an enlargement of the rough ER was observed in the cytoplasm. At the luminal surface, bleb-like cytoplasmic processes of the neuroepithelial cells containing monoribosomes protruded into the lumen. No cell necroses were visible in the neural tube after Col application. A condensation of chromatin in the nuclei of some neuroepithelial cells was visible 1.5 hr after HU application. Shortly thereafter, cell necroses appeared in the neural tube and 4 hr after HU application the entire spinal cord was strongly damaged. After simultaneous application of Col and HU, the ultrastructural changes in the neuroepithelial cells of the neural tube did not differ from the results obtained after Col application alone. In contrast to the results obtained after HU application alone, no necroses occurred after simultaneous application of Col and HU.     

等量分次施氮对冬枣15N和13C利用与分配特性的影响

以4年生盆栽冬枣为试材,采用¹³C、¹⁵N双标记示踪技术,在果实发育期研究了等氮量分次追施氮肥对冬枣植株¹⁵N和¹³C吸收、利用、积累和分配的影响.结果表明: 至果实采收期,冬枣各器官Ndff值(植株器官从肥料中吸收分配到的¹⁵N量对该器官全氮量的贡献率)随追氮次数的增多而显著增大.生殖器官(果实)和营养器官(叶片、枣吊、新生枣头枝和细根)的¹⁵N分配率以4次追氮处理最高,1次追氮处理最低,贮藏器官(主干、多年生枝和粗根)¹⁵N分配率的趋势相反;4次追氮处理¹⁵N利用率分别比1次和2次追氮处理高27.4%和15.5%.追氮次数越多,植株总氮量和¹⁵N吸收量越大;随时间的推移,1次追氮处理土壤¹⁵N丰度和总氮含量持续降低,2次追氮处理呈先升高后降低的趋势,4次追氮处理变化相对最为平稳,至处理后期显著高于其他处理;果实白熟至采收期,叶片叶绿素、氮含量和净光合速率均表现为4次追氮>2次追氮>1次追氮.不同处理¹³C同化物积累与分配不同.4次追氮处理¹³C固定总量分别是1次和2次追氮处理的1.1和1.2倍.增加追氮次数,促进了¹³C同化物向果实和贮藏器官的转移,而减少了向当年生营养器官的分配.综上,果实发育期4次追氮通过保证根层稳定、充足的氮素供应,提高了对氮素的吸收和利用,进而维持了较高的净光合速率,促进并优化了光合同化物的积累和分配,最有利于冬枣树体的生长及产量和品质的提高.     

等量分次施氮对冬枣15N和13C利用与分配特性的影响

以4年生盆栽冬枣为试材,采用¹³C、¹⁵N双标记示踪技术,在果实发育期研究了等氮量分次追施氮肥对冬枣植株¹⁵N和¹³C吸收、利用、积累和分配的影响.结果表明: 至果实采收期,冬枣各器官Ndff值(植株器官从肥料中吸收分配到的¹⁵N量对该器官全氮量的贡献率)随追氮次数的增多而显著增大.生殖器官(果实)和营养器官(叶片、枣吊、新生枣头枝和细根)的¹⁵N分配率以4次追氮处理最高,1次追氮处理最低,贮藏器官(主干、多年生枝和粗根)¹⁵N分配率的趋势相反;4次追氮处理¹⁵N利用率分别比1次和2次追氮处理高27.4%和15.5%.追氮次数越多,植株总氮量和¹⁵N吸收量越大;随时间的推移,1次追氮处理土壤¹⁵N丰度和总氮含量持续降低,2次追氮处理呈先升高后降低的趋势,4次追氮处理变化相对最为平稳,至处理后期显著高于其他处理;果实白熟至采收期,叶片叶绿素、氮含量和净光合速率均表现为4次追氮>2次追氮>1次追氮.不同处理¹³C同化物积累与分配不同.4次追氮处理¹³C固定总量分别是1次和2次追氮处理的1.1和1.2倍.增加追氮次数,促进了¹³C同化物向果实和贮藏器官的转移,而减少了向当年生营养器官的分配.综上,果实发育期4次追氮通过保证根层稳定、充足的氮素供应,提高了对氮素的吸收和利用,进而维持了较高的净光合速率,促进并优化了光合同化物的积累和分配,最有利于冬枣树体的生长及产量和品质的提高.     

A Framework for Automatic Adaptation of Tunable Distributed Applications

Increased platform heterogeneity and varying resource availability in distributed systems motivate the design of resource-aware applications, which ensure a desired performance level by continuously adapting their behavior to changing resource characteristics. In this paper, we describe an application-independent adaptation framework that simplifies the design of resource-aware applications. This framework eliminates the need for adaptation decisions to be explicitly programmed into the application by relying on two novel components: (1) a tunability interface, which exposes adaptation choices in the form of alternate application configurations while encapsulating core application functionality; and (2) a virtual execution environment, which emulates application execution under diverse resource availability enabling off-line collection of information about resulting behavior. Together, these components permit automatic run-time decisions on when to adapt by continuously monitoring resource conditions and application progress, and how to adapt by dynamically choosing an application configuration most appropriate for the prescribed user preference. We evaluate the framework using an interactive distributed image visualization application and a parallel image processing application. The framework permits automatic adaptation to changes in execution environment characteristics such as available network bandwidth or data arrival pattern by choosing a different application configuration that satisfies user preferences of output quality and timeliness.     

Effect of staking, nitrogen and potassium on growth and development in lesser yams: Dioscorea esculenta

Dry-matter accumulation was greater in staked than in unstaked plants of the lesser yam (Dioscorea esculenta). Staking, N and K application tended to increase the proportion of dry matter diverted into the tubers. Staking was the most important factor in increasing total tuber production, which was one and a half times greater in staked than in unstaked plants. Leaf-area development was closely and positively related to vine growth, and since staking and N application encouraged vine growth these treatments therefore led to the production of plants with greater leaf area. Leaf-area duration was increased by staking and N application and was closely and positively related to tuber yield. Staking and N application increased tuber number per plant while K application increased the size of individual tubers. Staking and K application increased bulking rate and both treatments increased the period of bulking by causing earlier tuber initiation.     

施磷对稻田土壤及田面水磷浓度影响的模拟

通过施用不同剂量磷肥稻田土壤淹水培养试验,研究了施磷对稻田土壤及田面水磷浓度的影响.结果表明,土壤速效磷（Olsen-P）浓度在施磷后迅速下降,60 d后趋于稳定.随施磷量的增加,土壤速效磷和缓效磷库量均递增,Olsen-P与施磷量呈正相关关系(y=21.49+0.086x),表明该土壤有很高的固磷潜力.施磷后田面水中全磷浓度呈先迅速上升后又缓慢下降趋势,施磷120 d后,田面水中全磷浓度与施磷量呈指数相关关系(y=0.3 72e^0.0022x),施磷量在400～800 kg·hm^-2之间田面水全磷浓度加速增长,如果施磷量达到或超过800 kg·hm^-2,则磷容易进入田面水并导致流失,低于该施磷量时,则磷进入田面水中的量较少.利用分段回归模型模拟土壤Olsen-P与水面全磷关系,预测出导致田面水中磷激增的土壤Olsen-P浓度“突变点”为82.7 mg·kg^-1,即施磷量为712 kg·hm^-2.因此,土壤Olsen-P浓度可作为预测田面水中磷损失程度的指标.