大棚草莓斜纹夜蛾的空间分布型

斜纹夜蛾Spodoptera litura(Fabricius)是大棚草莓生长初期的重要害虫。为明确斜纹夜蛾在草莓上的时空动态,连片调查了草莓上低龄幼虫数、中高龄幼虫数、受害叶片数以及叶片受害率,利用聚集度指标法、Taylor幂法则和IwaoM-m的回归法进行分析。结果表明低龄幼虫呈明显的聚集分布,中高龄幼虫则呈随机分布或均匀分布,受害叶片和受害率呈明显的聚集分布;通过聚集均数(λ)判断低龄幼虫高密度时λ>2,聚集由于成虫产卵块、初孵幼虫成聚集危害引起;低龄幼虫低密度时λ<2,聚集由植株间距等影响初孵幼虫的扩散因子引起;中高龄幼虫呈随机分布的田块的λ<2。*     

Binding of phenthoate to bovine serum albumin and reduced inhibition on acetylcholinesterase

Organophosphorus pesticides (OPs) are of environmental significance due to their high toxicity to animals. Binding to plasma proteins may effective influence the toxicological properties of xenobiotics. In an attempt to evaluate the affinity of phenthoate (PTA) to bovine serum albumin (BSA) and inhibitory ability of bound PTA to acetylcholinesterase (AChE), we investigated the interactions between phenthoate (PTA) and bovine serum albumin (BSA) using tryptophan fluorescence quenching and subsequent inhibition on AChE activity by PTA. The results showed that PTA caused the fluorescence quenching of BSA because of the formation of a PTA-BSA complex. Quenching constants (K_sv), determined using the Sterns-Volmer equation to provide a measure of the binding affinity between PTA and BSA at 303, 306, 310 and 313 K were (3.4295 ± 0.0763) × 10⁻⁴, (3.2446 ± 0.0635) × 10⁻⁴, (3.0434 ± 0.0856) × 10⁻⁴ and (2.8262 ± 0.0569) × 10⁻⁴ M⁻¹, respectively. The thermodynamic parameters, ΔH and ΔS were −25.04 kJ mol⁻¹ and 168.94 J mol⁻¹ K⁻¹, respectively, which indicated that the electrostatic interactions played a major role in PTA-BSA association. The presence of BSA consistently reduced the inhibitory ability of PTA on AChE, with the relative activity being increased from 46.98 to 61.71% for the concentration range of BSA between 0 and 4.0 g L⁻¹.     

mLIF、bFGF和SCF对鸡精原干细胞体外增殖的影响

采用MTT法分别检测mLIF、bFGF和SCF 3种细胞因子在单独添加和联合使用时对体外培养条件下的SSCs增殖的影响。结果表明:①3种细胞因子分别单独添加时,各实验组增殖效应与对照组比较差异显著(P<0.05);②3种因子联合使用时,低剂量组合共同促进SSCs的增殖,高剂量组合则抑制SSCs的增殖;③SCF、bFGF和mLIF的适宜剂量分别为10～20、10～20和10～15 ng/mL。     

用放射免疫法检测家蚕雌蛾体中雌二醇的含量

为了便于对大量家蚕雌蛾粉及其制品样本中雌二醇的含量进行快速测定,研究了家蚕雌蛾体中雌二醇含量的测定方法。以0.1 mol/L HCl为处理液,乙醚为提取溶剂,振荡重复抽提3次,可有效地提取家蚕雌蛾体中雌二醇。以90 g/L牛血清白蛋白Tris缓冲液为测定溶剂,采用均相竟争的放射免疫法,可精确、稳定地测定出家蚕雌蛾体中雌二醇含量。     

Simulated rain addition modifies diurnal patterns and temperature sensitivities of autotrophic and heterotrophic soil respiration in an arid desert ecosystem

The timing and magnitude of rainfall events in arid and semiarid regions are expected to change dramatically in future decades, which will likely greatly affect regional carbon cycles. To understand how increases in rainfall affect the diurnal patterns and temperature sensitivities (Q₁₀) of soil respiration (R_S) and its key components (i.e. heterotrophic respiration (R_H) and autotrophic respiration (R_A)), we conducted a manipulative field experiment in a desert ecosystem of Northwest China. We simulated five different scenarios of future rain regimes (0%, 25%, 50%, 75% and 100% increase over local annual mean precipitation) each month from May to September in 2009. We measured R_S and R_H every three hours on 6 and 16 days after the rain addition, and estimated R_A by calculating the difference between R_S and R_H. We found that rain addition significantly increased the daily mean R_S and its components on the two measurement days during the growing season. However, the diurnal pattern was different between the two respiration components. Rain addition significantly increased the daily Q₁₀ value of R_H but suppressed that of R_A on Day 6. Rain addition had no influence on daily Q₁₀ value of both respiration components on Day 16 when soil moisture was lower. In addition, we observed significantly higher daily Q₁₀ of R_H than R_A under all five rain addition treatments, indicating that microbial respiration is more temperature sensitive than root respiration in a short-time scale in this desert ecosystem. Thus, partitioning soil respiration into its two components, and analyzing the differential responses of R_H and R_A to future climate changes should be considered for more accurate predictions of soil respiration and regional carbon cycle in these arid and semiarid regions.     

MrMYB1-MrbHLH1:一个有潜力的园艺植物转基因可视化报告基因

将杨梅果实中参与花色苷生物合成的转录因子编码基因MrMYB1和MrbHLH1同时搭载到双元表达载体的多克隆位点内,重组成双价表达载体,通过农杆菌介导的叶盘法将其分别转入烟草、番茄和森林草莓,成功转化MrMYB1-MrbHLH1的烟草、番茄和森林草莓不定芽因大量积累花色苷而呈红色,与野生型或假阳性不定芽相比,表型差异明显;转化35S::MrMYB1-MrbHLH1的烟草和番茄植株中可显著积累花色苷呈红色,且该性状可稳定遗传。MrMYB1-MrbHLH1在3种园艺植物具有调控花色苷积累而使阳性转化植物部分组织器官呈现红色的功能,是1个有潜力的遗传转化可视化报告基因。     

生物酶在茶叶提取加工技术中的应用研究

茶是一种广受欢迎的软饮料,其中滋味醇浓且茶乳酪少的茶饮是最受青睐的。现代生物技术将外源生物酶应用于茶叶提取中,有利于茶叶细胞壁的浸渍、蛋白质的水解和茶乳酪的转溶,增加茶叶中茶多酚、茶黄素和氨基酸等的得率,改善茶叶色、香、味等品质。本文详细介绍了纤维素酶、果胶酶、单宁酶和蛋白酶等生物水解酶,并对这些酶在茶叶提取中的应用进行综述,同时对复合酶系在茶叶提取加工中的发展趋势进行了展望。     

Moisture loss is the major cause of firmness change during postharvest storage of blueberry

Blueberry softening is known to be influenced by cell wall modifications accompanying ripening but these changes appear to be largely complete by the time of harvest. In this study postharvest storage conditions were controlled so only the extent of water loss varied between treatments. A linear relationship between weight loss and loss of firmness (as assessed by a non-destructive compression test) was demonstrated. This relationship did not hold at very low weight loss, where instead, firming of blueberries during storage was found. Magnetic resonance imaging of berries confirmed significant shrinkage and loss of water in berries which had high weight loss, compared with more subtle effects on sub-epidermal water content in berries with very low weight loss. Treatments which restrict blueberry water loss to below 8% are likely to be beneficial in retaining acceptable berry firmness for up to three weeks’ storage.