甜菜BvGSTU9基因的生物信息学及在镉胁迫下的表达分析

为了进一步研究甜菜谷胱甘肽转移酶BvGSTU9 (LOC104894060)在重金属胁迫过程中的功能。本研究以‘780016B/12优’为实验材料,对该基因序列特征、结构、功能进行预测分析,并利用qPCR检测该基因在不同浓度镉胁迫下的表达量变化。结果显示甜菜BvGSTU9基因全长925 bp,开放阅读框675 bp,编码了由224个氨基酸组成的不稳定膜外蛋白。BvGSTU9与菠菜、藜麦的氨基酸序列相似性较高,与系统发育进化树分析结果基本相符。二级和三级结构预测表明该基因主要由α-螺旋、β-折叠、延伸链及无规则卷曲组成。qPCR显示BvGSTU9基因在不同浓度的镉胁迫下均受到不同程度的诱导,因此可以推断甜菜BvGSTU9基因无论从结构还是功能上,与镉逆境胁迫存在着一定的应答关系。研究结果也为甜菜耐重金属镉机制研究提供参考依据。     

镉毒性研究进展

本文综述了动物生产领域对镉的研究结果。这些内容包括 :(1)镉的化学特性 ;(2)镉在自然界的分布 ;(3)镉的生物学作用 ;(4)镉在动物体内的吸收和排泄 ;(5)镉对动物的危害 ;(6)镉与其它物质之间的关系 ;(7)镉的需要量、中毒量及饲料中镉的最大允许量。     

Biovailability of ivermectin administered orally to dogs

The bioavailability of three formulations of ivermectin was determined following oral administration to dogs. The average peak plasma level (C _max) of ivermectin administered in the standard tablet formulation at 6 and 100 µg/kg of body weight was 2.97 and 44.31 ng/g, respectively. This suggest dose-dependent pharmacokinetics.C _max and total ivermectin bioavailability, as assessed from the area under the plasma curve (AUC), were similar between two tablet formulations of ivermectin administered at 100 µg/kg. Furthermore,C _max was similar following administration of radiolabelled ivermectin at 6 µg/kg in either a beef-based chewable formulation or in the standard tablet formulation.     

X射线荧光光谱法快速测定稻谷中的镉

探索了一种对稻谷中重金属镉的快速、直接的测定方法,以适用稻谷集中收购、存储和流通过程中快速检测的的需要。样品无需前处理,直接磨成粉状即可上机测定。该方法采用X射线荧光光谱分析的原理,样品中的待测元素受激产生特征X射线,并由高性能探测器接收,得到镉元素的信号强度,然后根据信号强度与浓度的比例关系,经过软件处理自动计算样品中镉的含量,20min内完成精确定量。检出限可达到0.034mg/kg,实物标样标准偏差为0.016。此方法简单快速,并且准确性高,重现性好,可广泛应用于稻谷中镉的快速检测。     

植物提取物超微粉体制备技术研究进展

植物提取物大都是脂溶性成分,因其水溶性差、生物利用度低,故其在临床上的推广应用受到了一定程度的限制。文章综述了有关能增强植物提取物水溶性的超临界流体技术、高压均质技术、液相可控沉淀技术、喷雾干燥技术、乳化溶剂扩散技术、机械研磨技术等超微粉体制备技术的研究进展。     

6种钝化剂对糙米镉含量及镉在水稻中的转移和富集的影响

旨在为合理使用钝化剂及水稻糙米镉(Cd)含量与Cd在水稻体内富集和转移的关系提供一定的理论依据。从6种钝化剂中筛选出能够抑制糙米Cd积累的材料,通过对不同超标程度水稻组的产量、糙米Cd含量、各个器官对Cd的富集系数和转移系数进行统计分析,探讨不同钝化剂对Cd在水稻体内转移和富集的影响。结果表明:与对照相比,低、中浓度C材料和FA材料能够降低糙米中Cd浓度;FB材料和中、高浓度FD材料会促使糙米中Cd的积累。水稻各器官对Cd富集能力,无超标水稻为根茎米叶糠,超标水稻为根茎米糠叶;Cd向糙米的转移途径中,在不超标水稻组中糠—米的转移能力最强,在超标水稻组中叶—米的转移能力最强。     

黑豆—油菜与大豆—油菜轮作模式土壤镉修复能力比较

通过设置黑豆-油菜、大豆-油菜的轮作模式在湖南醴陵进行大田试验,结果发现黑豆表现出较强的镉富集能力,其根、茎、叶及果壳中镉含量分别为2.14、2.63、4.10及1.34 mg/kg,富集系数均在1以上。油菜各个部位镉含量较高的分别为叶与茎,达到了7.13和4.73 mg/kg。黑豆各部位镉转运系数均高于大豆,各油料作物提取的重金属主要集中在茎与叶。大豆叶的镉富集系数为2.06,茎的镉富集系数为0.86,明显低于黑豆同部位的富集能力。每公顷土地经过一轮黑豆-油菜、大豆-油菜轮作分别能够从土壤中提取73.52 g和51.68 g的镉,对土壤重金属镉的修复效率约为3%。     

Reduction in cadmium accumulation in japonica rice grains by CRISPR/Cas9-mediated editing of OsNRAMP5

Cadmium (Cd) intake is harmful to human health and Cd contamination in rice grains represents a severe threat to those consuming rice as a staple food. Knockout of Cd transporters is a promising strategy to reduce Cd accumulation in rice grains. OsNRAMP5 is the major transporter for Cd and manganese (Mn) uptake in rice. Nevertheless, it is uncertain whether knockout of OsNRAMP5 is applicable to produce low Cd rice without affecting plant growth and grain yield. In this study, we adopted CRISPR/Cas9-based gene editing technology to knock out OsNRAMP5 in two japonica varieties. We generated three independent transgene-free osnramp5 mutants and investigated the effect of osnramp5 mutations on Cd accumulation and plant growth. Hydroponic experiments showed that plant growth and chlorophyll content were significantly reduced in osnramp5 mutants at low Mn conditions, and this defective growth in the mutants could be fully rescued by supply of high levels of Mn. Cd and Mn accumulation in both roots and shoots was markedly reduced in the mutants compared to that in wild-type plants. In paddy field experiments, although Cd in flag leaves and grains was greatly reduced in osnramp5 mutants, some agronomic traits including plant height, seed setting rate, and grain number per panicle were affected in the mutants, which ultimately caused a mild reduction in grain yield. The reduced plant growth in the mutants can be attributed to a marked decrease in Mn accumulation. Our results reveal that the manipulation of OsNRAMP5 should be treated with caution: When assessing the applicability of osnramp5 mutants, soil pH and soil water content in paddy fields need to be taken into consideration, since they might affect the levels of available Mn in the soil and consequently determine the effect of the mutation on grain yield.     

硒肥与钝化材料组配对土壤Cd钝化及稻米Cd消减效果

为了探讨不同硒肥施用方式联合钝化材料对土壤镉钝化和稻米镉消减的效果,采用盆栽试验的方式,选用亚硒酸钠作为硒肥,钙镁磷肥和硅藻土作为钝化材料,设置基施硒肥+钙镁磷肥+硅藻土和叶面喷施硒肥+钙镁磷肥+硅藻土2种方式,研究其不同用量对镉污染酸性稻田土壤修复与安全利用的影响。结果表明：随着施用量的增加,稻米产量增加,基施硒肥产量略高于叶面喷施硒肥,产量差为 2.115 g/pot,与对照(CK)相比,基施0.28%钙镁磷肥+0.12%硅藻土+0.004‰硒(T3)能够提高1.68倍的稻米产量;随着施用量的增加,pH升高,有效Cd降低,有机质与CEC变化不大;基施硒肥与叶面喷施硒肥处理对土壤pH、有机质与CEC差异不显著,但基施硒肥处理有效Cd含量略低于叶面喷施硒肥处理,T3对土壤Cd的钝化效果最佳;随着基施硒肥用量的增加,稻米Cd含量降低,随着叶面喷施硒肥用量的增加,稻米Cd含量先降低后升高,基施硒肥处理对稻米Cd的消减程度强于叶面喷施硒肥处理,相差 0.021 mg/kg,与对照(CK)相比,T3处理稻米Cd降低0.063 mg/kg。可见,硒对调控稻米镉累积具有重要作用,且基施硒肥强于叶面喷施。综上所述,基施0.28%钙镁磷肥+0.12%硅藻土+0.004‰硒对土壤Cd钝化与稻米Cd消减的效果最佳,值得在镉污染稻田推广应用。