Effective use of glucose rather than starch in formulated semimoist diets of common octopus (Octopus vulgaris)

The aim of the present work was to test the capacity of Octopus vulgaris to use carbohydrates supplied in three diets: a diet without added carbohydrates (diet C0: 500 g kg^?1 water, 200 g kg^?1 gelatine, 100 g kg^?1 egg yolk powder, 50 g kg^?1 freeze‐dried Sardinella aurita and 150 g kg^?1 freeze‐dried Todarodes sagittatus) and two obtained by substituting 50 g kg^?1 of T. sagittatus by glucose (diet GLU50) or by starch (diet STA50). The most stable and best‐accepted diet was STA50 (SFR 1.26%BW day^?1) although there were no significant differences in the growth rates obtained with the three diets: 10.12 g day^?1, 9.37 g day^?1 and 11.22 g day^?1 for C0, GLU50 and STA50, respectively (P > 0.05). The feed efficiency indices were better for GLU50, of particular note being the protein productive value of 71.88% and a feed conversion ratio lower than 1. Protein and lipid digestibility were similar in all the three diets (96–98% for proteins and 85–94% for lipids), whereas carbohydrate digestibility was higher in GLU50 (98%) than in C0 (84%) and STA50 (0.33%). The content of carbohydrates increased in muscle and the digestive gland as a consequence of the increased carbohydrates intake.     

生物质及其衍生糖类制备乳酸的研究进展

生物质资源是地球上产量最多、分布最广的可再生资源,利用农业废弃物等各种生物质制备高附加值平台化合物对解决能源危机和环境问题具有重要的意义。本文在相关研究现状的基础上,简要总结了发酵法、化学催化法等以生物质及其衍生糖类为底物制备乳酸的工艺方法,并对相应体系进行了分析,提出了这一领域中近期的热点及发展趋势,以期对后续研究提供参考。     

白羊草光合特性及非结构性碳水化合物含量对 CO2 浓度倍增和干旱胁迫的响应

【目的】 探明 CO₂ 浓度倍增对干旱胁迫下白羊草光合特性及非结构性碳水化合物含量的影响,为未来大气 CO₂ 浓度升高以及干旱、半干旱地区水分亏缺等逆境下白羊草的生长提供理论依据和技术参数。 【方法】 盆栽试验采用裂区设计,研究了黄土丘陵区典型草本植物白羊草光合特性和非结构性碳水化合物 (NSC) 及其组分 (可溶性糖和淀粉) 的含量对不同 CO₂ 浓度 (400 μmol/mol 和 800 μmol/mol) 和不同水分处理 [35%～40% FC (重度干旱胁迫)、55%～60% FC (轻度干旱胁迫) 和 75%～80% FC (对照)] 的响应。 【结果】 CO₂ 浓度倍增和干旱胁迫对白羊草光合–光响应曲线参数和 NSC 及其组分含量有显著影响,但 2 个因素之间没有显著的交互作用。CO₂ 浓度倍增显著提高了白羊草叶片最大净光合速率 (P_max )、表观量子效率 (AQY)、光饱和点 (LSP) 和光补偿点 (LCP)(P < 0.01),而干旱胁迫则显著降低了P_max 、AQY 和LSP (P < 0.01)。CO₂ 浓度倍增和干旱胁迫均提高了白羊草地上部分可溶性糖含量。在正常 CO₂ 浓度条件下,与对照相比,轻度干旱胁迫和重度干旱胁迫均显著降低了白羊草地上部分和根系部分淀粉含量。CO₂ 浓度倍增使对照、轻度干旱胁迫和重度干旱胁迫处理下白羊草地上部分淀粉含量分别提高了 17.4%、44.2% 和 18.7%,根系部分淀粉含量分别提高了 17.3%、88.4% 和 54.4%。轻度和重度干旱胁迫均显著降低了正常 CO₂ 浓度条件下白羊草根系部分 NSC 含量。CO₂ 浓度倍增显著提高了对照处理和轻度干旱胁迫处理下白羊草地上部分以及轻度干旱胁迫处理和重度干旱胁迫处理下白羊草根系部分 NSC 含量。在正常 CO₂ 浓度下,轻度和重度干旱胁迫导致白羊草地上部分和根系部分可溶性糖含量与总 NSC 含量比值的显著提高。在倍增 CO₂ 浓度下,重度干旱胁迫显著提高了白羊草地上部分可溶性糖含量与总 NSC 含量的比值,而对照处理和轻度干旱胁迫处理无显著差异。 【结论】 干旱胁迫促进了白羊草体内淀粉向可溶性糖的转化,导致可溶性糖含量的升高和淀粉含量的降低。CO₂ 浓度倍增促进了白羊草地上部分和根系部分淀粉和 NSC 含量的积累,为干旱胁迫下白羊草生理代谢活动所需可溶性糖提供了来源。CO₂ 浓度升高能够缓解干旱胁迫造成的不利影响,提高了白羊草的抗旱性。      

Differential responses of grain yield,grain protein,and their associated traits to nitrogen supply in soft red winter wheat

Increased application of nitrogen fertilizers has significantly raised grain yield and protein concentration in wheat. However, only 30–50% of applied fertilizer nitrogen are usually utilized by the plant. In this study, four soft red winter wheat genotypes (Triticum aestivum L., IL07‐4415, MD05W10208‐11‐8, OH06‐150‐57 and Sisson) were grown under three different nitrogen regimes (high, medium, and low) in a greenhouse, and grain yield, grain protein concentration, nitrogen use efficiency (NUE) and their associated traits were evaluated. Among the four genotypes, a high‐yielding cultivar, Sisson, exhibited superior performance in terms of grain weight plant⁻¹ and NUE for yield (NUEY) at low nitrogen due to maintained grain number spike⁻¹ and harvest index. Significant yield losses due to nitrogen limitation were attributable to reduced spike number plant⁻¹ and grain number spike⁻¹ in the other genotypes. Interestingly, a linear relationship between NUEY and NUE for grain protein (NUEP) was detected at high (R ² = 0.67) and low (R ² = 0.42) nitrogen; both of these traits were positively correlated with grain number spike⁻¹, 1000‐seed weight, and harvest index under nitrogen‐limited conditions (R ² = 0.35–0.48). These results suggest that simultaneous improvement of NUEY and NUEP could be achieved through the selection of the three yield components (grain number spike⁻¹, 1000‐seed weight, and harvest index) at low nitrogen.     

紫花苜蓿主根内非结构性碳水化合物累积及其与抗寒性的关系

以国内外5个不同紫花苜蓿品种为试验材料,测定当年植株人工冷冻胁迫处理前后的非结构性碳水化合物(NSC)累积情况,以人工控温后的再生长率为衡量指标,研究NSC累积情况与抗寒性的关系及冷冻前后的NSC累积情况。结果表明,秋季主根内可溶性糖积累浓度显著正相关于各品种的冻后再生长率(R=0.936,P0.01);淀粉浓度则与抗寒性间呈显著负相关(R=-0.880,P0.05),且根部淀粉累积总量显著负相关于其抗寒性(R=-0.923,P0.05);人工冷冻过程中伴随各苜蓿品种主根内淀粉浓度下降糖浓度升高,两者存在动态平衡。在苜蓿冷冻后返青生长过程中,主根内总非结构性碳水化合物(TNC)浓度下降。     

Impact of frost and plant age on compensatory growth in timothy and perennial ryegrass during winter

Two cultivars of each of two contrasting grass species, timothy ( Phleum pratense L.) and perennial ryegrass ( Lolium perenne L.), sown either in May or July, were sampled for dry matter (DM) weight of roots and herbage in late October (end of main growing season) and examined for regrowth when exposed to a frost treatment (−8 to −10°C in darkness for 48 h) in late January, early March and late April. The frost treatment caused compensatory root and herbage growth, and regrowth of roots in March and April was greater than regrowth of herbage. Early-sown plants had higher DM weights of roots and herbage than late-sown plants in October but had the lowest survival rate when exposed to the frost treatment in April. Compensatory growth of root and herbage in response to moderate frosts occurred in January and March in all cultivars, and in the most frost-resistant timothy cultivar in April. Concentration of total carbohydrates increased from October to March with the greatest increase in the most winter-hardy cultivar of each species, and then decreased in April. An indirect correlation between concentration of total carbohydrates and tolerance to moderate frost was indicated, and plant survival and ability for compensatory growth were also associated with differences in adaptation related to winter survival in the cultivars tested.     

假俭草抗寒性与体内碳水化合物、脯氨酸、可溶性蛋白含量的关系

为了阐述假俭草(Eremochloa ophiuroides(Munro.)Hack.)的抗寒性与碳水化合物、脯氨酸、可溶性蛋白含量季节动态变化之间的关系,于2008年10月-2009年5月,研究了在自然温度变化过程中,假俭草E126匍匐茎中碳水化合物、脯氨酸、可溶性蛋白的季节性动态变化及其与半致死温度(LT₅₀)变化的关系。结果表明:在越冬前后假俭草E126匍匐茎LT₅₀呈现先降低后升高的季节变化趋势,可溶性总糖、蔗糖、果糖含量,可溶性总糖淀粉比率以及脯氨酸含量伴随田间气温变化均呈现先升高后降低的趋势,可溶性蛋白、淀粉含量则呈现出先降低又升高的趋势。假俭草E126匍匐茎LT₅₀季节变化与可溶性总糖、蔗糖、果糖含量,可溶性总糖淀粉比率季节变化之间存在极显著负相关(P<0.01),而与淀粉含量、脯氨酸含量、可溶性蛋白含量的季节变化间相关性不显著。因此,可溶性总糖含量、蔗糖含量、果糖含量、可溶性总糖淀粉比率对其冬季抗寒性增强有重要作用。     

Sequence and phylogenetic analysis of the non-structural 3A and 3B protein-coding regions of foot-and-mouth disease virus subtype A Iran 05

The A Iran 05 foot-and-mouth disease virus (FMDV) subtype was detected in Iran during 2005 and has proven to be highly virulent. This study was undertaken to focus on molecular and phylogenetic analysis of 3A and 3B coding-regions in the A Iran 05 field isolate. To assess the genetic relatedness of A Iran 05 isolate the nucleotide and predicted amino acid sequences of the 3AB region of type A FMDV isolates were compared with twenty previously described type A FMDV isolates. The phylogenetic tree based on the 672 bp 3AB gene sequences of type A FMDV from thirteen different locations clustered them into five distinct lineages. The A Iran 05 isolate clustered in lineage A along with four type A variants and was closely matched with viruses isolated in Turkey and Pakistan during 2005~2006. The number of protein sequence differences exhibited by each of the isolates revealed that A Iran 05 isolate contains three amino acid substitutions at positions 47 and 119 of 3A and 27 of the 3B coding region. The nucleotide identity between A Iran 05 and the other four isolates of lineage A was estimated to be 98%.     

甲型流感病毒多功能蛋白质NS1的研究进展

近年来大量的研究结果表明,甲型流感病毒的非结构蛋白质1(NS1)是在感染病毒期间具有多个辅助功能的毒力因子,为揭示该人畜共患病毒的致病性机理提供重要参考价值。这篇文章综述了该病毒蛋白质一些最新研究进展,包括NS1的合成、结构、亚细胞定位及在病毒复制机制、宿主天然免疫应答或/和适应性免疫应答、细胞信号传导中发挥各种作用。作者重点阐述了NS1-RNA之间和NS1-蛋白质之间的相互作用,因为它们都是上述功能和过程的基础。同时突出不同毒株NS1蛋白可能特有的特性,鉴于此,也讨论了NS1对人和动物甲型流感病毒致病性的某些作用。最后概述NS1可能应用于流感疫苗的研制、新抗病毒药物的研发等。同时比较了乙、丙型流感病毒NS1研究新进展。     

Effect of different girdling dates on tree growth,fruit characteristics and reserve accumulation in a late-maturing persimmon

Trunks of 8-year-old vigorous ‘Fuyu’ persimmon (Diospyros kaki Thunb.) were girdled to a 1 cm width on April 20 and June 10 2004. Tree growth and fruit characteristics were monitored for two years, with special emphasis on the carry-over effect in 2005. Girdling reduced trunk and shoot growth especially of April-girdled trees over two consecutive years. However, the most significant effect of girdling was in the occurrence of water sprouts: a control tree had 29.5 in 2004 and 27.3 in 2005, whereas the April-girdled trees had only 0.3 and 5.3, respectively. Girdling increased fruit set by nearly 50% and enhanced fruit colour in 2004 only. Girdling date did not significantly affect fruit size and soluble solids for two years. Fruit flesh of girdled trees in 2004, especially in the April-girdled trees, had lower N and P concentrations. The levels of starch, soluble sugars, and inorganic elements in flower-bearing distal buds measured just before new growth in 2005 were not significantly altered by the girdling in 2004.