Expression of late maturity α-amylase in wheat containing gibberellic acid insensitivity genes

Summary Two wheat cultivars, Spica and Lerma 52, which consistently produce high levels of mg src="/content/l381637p20m44327/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-amylase during the later stages of grain development (late maturity mg src="/content/l381637p20m44327/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-amylase), were crossed with a set of four near-isogenic lines carrying the tall (rht) allele or one of the dwarfing genes Rht1, Rht2 or Rht3 (GA-insensitive alleles). The F₁ and F₂ populations were developed and analysed for grain mg src="/content/l381637p20m44327/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-amylase and plant height. The Rht3 gene exhibited the strongest influence on plant height and strongly inhibited new mg src="/content/l381637p20m44327/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-amylase synthesis during the later part of grain ripening. By comparison, Rht1 and Rht2 had a less pronounced effect but still significantly reduced the expression of late maturity mg src="/content/l381637p20m44327/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-amylase. These observations suggest that gibberellic acid is involved either directly or indirectly in this phenomenon. The implications of the effect of dwarfing genes on expression of late maturity mg src="/content/l381637p20m44327/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-amylase are discussed in relation to cultivar improvement and to the identification and control of high mg src="/content/l381637p20m44327/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-amylase germplasm.     

Polymorphisms of α-amylase activity in barley landraces and cultivars from China

Summary mg src="/content/h14411r73128m01x/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-Amylase activity was assayed by measuring reducing power equivalent for 80 accessions of cultivated barley, Hordeum vulgare L., representing major barley growing areas of China. Replications were applied at two different levels of the experiment and enzyme activity was assayed on four consecutive days starting on the 6th day after germination. The area under the curve formed by connecting the four data points was integrated as the measurement of mg src="/content/h14411r73128m01x/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-amylase activity. The results established that there was extensive variation in mg src="/content/h14411r73128m01x/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-amylase activity in cultivated barley; about three-fold difference existed among accessions assayed. Comparisons were also made between six- and two-rowed, and between covered and naked barleys. The results showed that high mg src="/content/h14411r73128m01x/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-amylase activity was not necessarily associated with six-rowed type, and that covered barleys were slightly higher in mg src="/content/h14411r73128m01x/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-amylase activity than naked ones.     

猪m6A去甲基化酶FTO、ALKBH5基因表达水平与大肠杆菌F18感染抗性的关系分析

为了探讨猪6-甲基腺嘌呤（m⁶A）去甲基化酶mRNA表达水平与仔猪大肠杆菌F18抗性的关系,本研究运用实时荧光定量PCR方法检测m⁶A去甲基化酶FTO和ALKBH5基因在35日龄苏太猪断奶仔猪大肠杆菌F18抗性型和敏感型个体十二指肠和空肠组织中的mRNA表达差异,同时分别利用F18ab、F18ac大肠杆菌菌体刺激和内毒素LPS诱导猪小肠上皮细胞（IPEC-J2）,检测FTO、ALKBH5基因表达变化。结果表明,FTO、ALKBH5基因在抗性型个体十二指肠和空肠中的表达量均极显著或显著高于敏感型个体（P<0.01,P<0.05）;不同F18大肠杆菌菌体刺激IPEC-J2细胞后,FTO基因表达水平均无显著变化（P>0.05）,而ALKBH5基因在F18ac刺激后表达量显著上调（P<0.05）;LPS诱导4 h时,FTO和ALKBH5基因表达量均显著上调（P<0.05）。本研究在细胞和个体水平上初步验证并发现了m⁶A去甲基化酶FTO和ALKBH5基因表达水平与大肠杆菌感染仔猪密切相关,为今后深入研究RNA去甲基化修饰在仔猪细菌性腹泻调控中的作用机制提供了理论基础。     

奥运会男子400m跑的周期性研究

以历届奥运会400m跑前3名的成绩为研究对象,将奥运会男子400m跑整个发展历程分成4个不同的历史阶段,对影响奥运会男子400m跑的绝对速度能力、速度耐力能力两个重要因素进入深入分析,研究结果表明：在奥运会的整个发展历程中,男子400m跑成绩整体呈上升的发展趋势,经历了快、慢、快、慢4个发展周期,下一个将是快速上升发展周期;绝对速度能力整体呈上升的发展趋势,与男子400m跑成绩的发展周期基本相同,速度耐力能力整体呈缓慢上升的发展趋势,与男子400m跑成绩、绝对速度能力的发展周期不同步;绝对速度能力是奥运会男子400m跑的整个发展历程中的主导因素,并影响着前3个阶段的发展趋势,而在1988－2012阶段中,速度耐力能力转变成了主导因素;男子400m跑将进入以速度耐力能力为核心的发展周期,应强调发展运动员的速度耐力能力。     

Incorporation of yolk fatty acids into body lipids of goldfish (Carassius auratus L.) larvae raised at two different temperatures

In five separate experiments, eggs from a single female goldfish were fertilized at 20&amp;deg;C. They were incubated at 22&amp;deg;C for 6 hours, after which some of the eggs were transferred to 13&amp;deg;C. When a defined post-hatch developmental stage was reached, lipid extracts were prepared from larvae, both with yolk sacs intact and after removal of the yolk sac by dissection. Other larvae were sampled at yolk exhaustion. Gas chromatographic analysis of fatty acid profiles revealed that larvae incorporated 16:0, 18:0, 20:4 (n&amp;#x2013;6) and 22:6 (n&amp;#x2013;3) into their tissues in proportions higher than those present in the eggs from which they were derived. At 22&amp;deg;C, these trends were particularly apparent at yolk exhaustion. At 13&amp;deg;C, proportions of polyunsaturated fatty acids in the bodies of newly hatched larvae were higher than those in the 22&amp;deg;C larval bodies. Monounsaturated fatty acids were preferentially depleted during development, especially in larvae from high quality eggs. No dependence of egg quality, as assessed by larval viability at 22&amp;deg;C, on total egg lipid mass or fatty acid composition was found. Larvae from the lowest quality eggs showed a reduced preference for incorporation of (n&amp;#x2013;3) polyunsaturated fatty acids into their tissues.     

Oxidative metabolism in a teleost,Anabas testudineus Bloch: effect of testosterone and estradiol-17β on hepatic enzyme activities

Testosterone (T) administration to maleAnabas testudineus significantly stimulated the activities of cytochrome oxidase, mg src="/content/m78315427121t6h4/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-glycerophosphate dehydrogenase (mg src="/content/m78315427121t6h4/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-GPDH) and Mg²⁺ adenosine triphosphatase (Mg²⁺ ATPase) and inhibited lactate dehydrogenase (LDH), cytosolic and mitochondrial malate dehydrogenases (MDH). The activities of succinate dehydrogenase (SDH), glucose-6-phosphate dehydrogenase (G-6-PDH) and catalase were unaffected by testosterone treatment. Administration of estradiol-17mg src="/content/m78315427121t6h4/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0"> (E2) in female fish, significantly stimulated cytochrome oxidase activity, inhibited Mg²⁺ ATPase, SDH, catalase and cytosolic and mitochondrial MDH activity, and was without effect on other enzymes studied.The simultaneous injections of actinomycin D or chloramphenicol and T or E2 prevented the hormonal influence on hepatic enzyme activities. The present study demonstrates that inA. testudineus sex steroids influence hepatic oxidative metabolism by a mechanism sensitive to the action of inhibitors of protein synthesis.     

Partial or total replacement of fish meal byplant protein affects gonadal development and plasma17 β-estradiol levels in female Nile tilapia

This study was conducted to evaluate theeffect of plant proteinmg src="/content/m8w2g4161336683u/xxlarge8208.gif" alt="dash" align="MIDDLE" BORDER="0">based diets on gonadaldevelopment and plasma 17 mg src="/content/m8w2g4161336683u/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-estradiol (E2) levelin female Nile tilapia Oreochromis niloticus.Fish with a mean body weight of 6.7 (0.1) g were fedfour different diets with the same digestible protein(DP) and digestible energy (DE) containing gradedlevels of a mixture of plant ingredients as partial ortotal replacement of fish meal protein for 20 weeks.The control diet (D0) was based on fish meal, twodiets containing 33% (D33) and 66% (D66) of plantprotein, and one diet containing only plant protein(D100). Fish were sampled at 12 and 20 weeks. Nosignificant differences were found in different stagesof oocyte development and plasma E2 levels betweentilapia fed diets D0 and D100 at 12 weeks. Eight weekslater tilapia fed diet D0 showed a higher (P < 0.05)level of E2 than the D100 group. This difference andthe reduced proportion of vitellogenic and matureoocytes demonstrated that diets containing only plantprotein are less efficient in terms of tilapia growthand consequently ovarian development.     

Land-use legacy of historical tree harvesting for charcoal production in a semi-arid woodland

Historical processes may have longer lasting effects in arid forest and woodlands because of slow rates of succession. We investigated the influence of historical tree harvesting upon contemporary spatial dynamics of pinyon-juniper woodland in the western United States. Despite intensive and widespread harvesting of woodland by the charcoal industry during the late 19th century, the role of afforestation has seldom been addressed as a potential mechanism for the dramatic expansion of pinyon-juniper woodlands over the past century. Spatial models of disturbance processes are one way to ascertain effects of such historical influences. We developed a process-based spatial model to estimate the historical tree harvest pressure according to a parsimonious set of rules and constraints. The model used a convection-diffusion approach that incorporated the influences of topography, transportation, and mining production. We used a combination of field-surveyed, archaeological, historical, and GIS data sets to calibrate, validate, and compare the alternative mathematical models. Model results were consistent with the historical harvest evidence (AUC&amp;#xA0;&amp;gt;&amp;#xA0;0.66), with high harvest intensity closer to the mining districts, quickly decreasing at the maximum distance of influence. Performance was improved by including the local terrain. Harvesting initially showed radial patterns emanating from the significant mining districts, and then gradually expanded northward with development of the railway system. Our spatial modeling approach provides a means to assess the pattern and magnitude of historical tree harvesting in semi-arid woodlands. The general approach can be applied to explore the importance of other historical disturbance and cultural processes, whose effects may no longer be evident, in forests and woodlands worldwide.     

间套作条件下作物根系数量与活性的空间分布及变化规律研究 Ⅱ.间作早春玉米根系数量与活性的空间分布及变化规律

本文在冬小麦‖早春玉米 /夏玉米条件下 ,研究了麦田间作地膜覆盖早春播种玉米 (简称早春玉米 )根系数量与活性的空间分布及变化规律 ,主要结果 :(1)间作地膜覆盖早春玉米拔节期根深 10 0cm左右 ,大口期 140 cm左右 ,乳熟期达到最大根深 160 cm左右。 (2 )随生育进程推进 ,根量与根重密度基本呈小→大→小变化 ;根系数量及重量密度在垂直土体中呈“T”型分布 ,0～ 2 0 cm为高密度层 ,2 0～ 4 0、 4 0～ 80 cm为中密度层 ,80～ 12 0 cm为低密度层 ,12 0～ 160 cm为稀密度层。根系相对稳定后 ,约有 75 %的根干重分布在 0～ 2 0 cm土层 ,85 %左右在 4 0 cm以上 ,95 %左右在 80 cm以上。 (3)根系含水率在垂直空间呈上低下高趋势 ,随生育期推进 ,含水率呈下降趋势。 (4 )根系活性与根量相反呈倒“T”型分布 ,根系活性随生育进程推进 ,呈减低趋势 ,且活力高位点又呈下移变化 ,拔节期 2 0～ 4 0cm根系活性较高 ,大口期 4 0 cm以下较高 ,乳熟期和成熟期以 80 cm以下较高。 (5 )根系 TTC还原总量及总量密度随生育进程推进呈低→高→低变化 ,以大口期为高。上下又呈“T”型分布 ,0～ 2 0 cm为高量高密度区 ,2 0～ 80 cm为中量中密度区 ,80～ 12 0 cm为低量低密度区 ,12 0～ 160 cm为稀量稀密度区。 (6)成熟期 2 0