Hybridization between Crassostrea hongkongensis and Crassostrea ariakensis at Different Salinities

To evaluate the survival and growth performance of hybrid larvae and juveniles, we conducted hybridization experiments between Crassostrea hongkongensis and Crassostrea ariakensis at three salinities (15, 23, and 30 ppt). Hybrid fertilization occurred in one direction (C. hongkongensis ♀ and C. ariakensis ♂), and the fertilization rates did not differ significantly among the three trial salinities. Molecular genetics analysis revealed that hybrid progenies were true hybrids. Hybrid juveniles survived better than C. hongkongensis juveniles at a salinity of 30 ppt. Hybrid larvae and juveniles showed intermediate growth between C. hongkongensis and C. ariakensis progenies. The growth of hybrid juveniles was significantly greater than that of C. hongkongensis juveniles at a salinity of 30 ppt. Overall, C. hongkongensis has a high economic value but favorable hatchery and farm of this species is restricted to lower salinity sites. Because the hybrids were shown to have greater growth and survival characteristics at high salinity, hybrids may be a more desirable candidate to be cultured in those areas of China with higher salinities, such as the Bohai Sea of China where the salinity is usually 30 ppt.     

新型鸭呼肠孤病毒DH13株结构蛋白σB的原核表达及免疫原性分析

本研究旨在利用原核表达系统表达新型鸭呼肠孤病毒（NDRV） DH13株重组σB蛋白,并检测其免疫原性,为NDRV基因工程疫苗研制等提供物质材料。采用RT-PCR方法扩增获得NDRV σB基因,构建原核表达重组质粒pET-30a-σB和pET-32a-σB,将2个重组质粒转化大肠杆菌BL21（DE3）感受态细胞,利用IPTG诱导获得相应的重组蛋白,通过SDS-PAGE分析重组蛋白的表达形式。纯化无His的σB蛋白,并以此蛋白作为免疫原免疫新西兰白兔,制备兔源多克隆抗体。利用Ni²⁺柱亲和层析法纯化含His的σB蛋白,以此蛋白作为检测原,通过间接ELISA方法测定兔源多克隆抗体效价;Western blotting鉴定多克隆抗体与重组蛋白的特异性识别能力。结果显示,PCR扩增获得大小约为1 100 bp的σB基因片段。SDS-PAGE结果显示,高效表达出了2种重组σB蛋白,大小分别约为41和46 ku,均以包涵体形式存在。间接ELISA结果显示,制备的多克隆抗体效价达1∶204 800,能特异性地识别原核表达的重组蛋白,表明重组无His的σB蛋白具有良好的免疫原性。Western blotting特异性鉴定结果显示,含His的σB蛋白和无His的σB蛋白均与制备的兔源多克隆抗体发生特异性反应,表明原核表达得到的重组σB蛋白具备良好的反应原性。本试验利用原核表达系统成功地表达出了重组σB蛋白,并证实了重组NDRV σB蛋白具有良好的免疫原性及反应原性,该结果将有助于后续对NDRV σB蛋白生物学功能的鉴定、NDRV诊断用抗原的制备及NDRV新型疫苗的研制。     

依朗芷硬胶在广州石化厂矿区的生长表现分析

1989年3月,引入依朗芷硬胶在广州石化厂矿区作抗污染与行道树种种植,16年的试种结果和 4年育苗试验表明:该树种生长良好,每年都能开花结实,叶色翠绿,终年不凋,自然整枝良好,树冠近球形, 喜温暖和阳光充足环境,对土壤要求不严,对肥水要求不高,耐土壤瘠薄,耐干旱,无病虫害,抗污染能力强, 种子繁殖出苗率高,苗期生长速度也较快。该树种适应广州地区的气候条件,可广泛应用于行道树、厂矿区绿化、庭园绿化、森林公园和风景林建设等。     

上海市水产品比较优势研究

改革开放以来，上海渔业经济的发展取得了巨大成就，但上海也为此付出了巨大代价：一是许多宝贵的水产资源逐渐衰竭；二是水产养殖导致了环境污染。上海如果要实现渔业的可持续发展，就必须注意搞好渔业产业结构的布局，发展自己的比较优势产业。文章针对如何确定上海渔业比较优势的问题详细介绍了用国内资源成本测定水产品比较优势的方法，并运用该方法测算了上海主要水产品的比较优势，旨在为上海市渔业生产结构的调整提供一定的参考和依据。     

新疆能源消费与经济增长的定量关系分析

运用灰色关联分析法和统计软件,分析了新疆能源消费总量、三次产业能源消费量、能源消费结构、能源利用率与经济增长之间的定量关系,结果表明:新疆能源消费与经济增长存在高度关联,其中能源消费总量与经济增长的关联度最高,达0.6899,其他各项指标与经济增长的关联度也大部分在0.6以上.新疆经济增长模式还属于粗放型,仍然依赖能源...     

不同佐剂制备的H9N2亚型禽流感(SS株)灭活疫苗的免疫效果和安全性评价

利用8种不同佐剂制备了16种H9N2亚型禽流感(SS株)灭活疫苗,对疫苗的物理性状、安全性、免疫效力及疫苗吸收情况进行检验,结果表明:疫苗外观、剂型、黏度均符合国家标准,物理性状稳定;接种SPF鸡后3周,16种疫苗HI抗体效价均超过11log2;剖检显示,大多数疫苗残留较少.     

低压配变台区三相负荷不平衡调节系统及装置研究

将终端分支箱及其出线作为一个整体进行研究,采用交换电源出线负荷的换相方式,通过简单实用的计算方法得出最优换相方案;同时,换相方式采用开关桥接结构和分时复用的方式,大大提高了开关器件的利用率。此外,利用电压锁相信息,对开关动作时间精准把控,达到换相过程负荷电压无跳变、负荷电流无断流的效果。     

Nitrapyrin affects the abundance of ammonia oxidizers rather than community structure in a yellow clay paddy soil

Purpose

Yellow clay paddy soil (Oxisols) is a low-yield soil with low nitrogen use efficiency (NUE) in southern China. The nitrification inhibitor nitrapyrin (2-chloro-6- (tricholoromethyl)-pyridine, CP) has been applied to improve NUE and reduce environmental pollution in paddy soil. However, the effects of nitrapyrin combined with nitrogen fertilizers on ammonia oxidizers in yellow clay paddy soil have not been examined.

Materials and methods

A randomized complete block design was set with three treatments: (1) without nitrogen fertilizer (CK), (2) common prilled urea (PU), and (3) prilled urea with nitrapyrin (NPU). Soil samples were collected from three treatments where CK, PU, and NPU had been repeatedly applied over 5 years. Soil samples were analyzed by quantitative PCR and 454 high-throughput pyrosequencing of the amoA gene to investigate the influence of nitrapyrin combined with nitrogen on the abundance and community structure of ammonia oxidizers in yellow clay paddy soil.

Results and discussion

The potential nitrification rate (PNR) of the soil was significantly correlated with the abundances of both ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB). Application of urea significantly stimulated AOA and AOB growth, whereas nitrapyrin exhibited inhibitory effects on AOA. Phylogenetic analysis showed that the most dominant operational taxonomic units (OTUs) of AOA and AOB were affiliated with the Nitrosotalea cluster and Nitrosospira cluster 12, respectively. AOA and AOB community structures were not altered by urea and nitrapyrin application.

Conclusions

Nitrogen fertilization stimulated nitrification and increased the population sizes of AOA and AOB. Nitrapyrin affected the abundance, but not community structure of ammonia oxidizers in yellow clay soil. Our results suggested that nitrapyrin improving NUE and inhibiting PNR was attributable to the inhibition of AOA growth.

     

Iron fertilizers applied to calcareous soil on the growth of peanut in a pot experiment

A greenhouse pot experiment was conducted with peanuts (Arachis hypogaea L., Fabceae) to evaluate iron compound fertilizers for improving within-plant iron content and correcting chlorosis caused by iron deficiency. Peanuts were planted in containers with calcareous soil fertilized with three different granular iron nitrogen, phosphorus and potassium (NPK) fertilizers (ferrous sulphate (FeSO₄)–NPK, Fe–ethylendiamine di (o-hydroxyphenylacetic) (EDDHA)–NPK and Fe–citrate–NPK). Iron nutrition, plant biomass, seed yield and quality of peanuts were significantly affected by the application of Fe–citrate–NPK and Fe–EDDHA–NPK to the soil. Iron concentrations in tissues were significantly greater for plants grown with Fe–citrate–NPK and Fe–EDDHA–NPK. The active iron concentration in the youngest leaves of peanuts was linearly related to the leaf chlorophyll (via soil and plant analyzer development measurements) recorded 50 and 80 days after planting. However, no significant differences between Fe–citrate–NPK and Fe–EDDHA–NPK were observed. Despite the large amount of total iron bound and dry matter, FeSO₄–NPK was less effective than Fe–citrate–NPK and Fe–EDDHA–NPK to improve iron uptake. The results showed that application of Fe–citrate–NPK was as effective as application of Fe–EDDHA–NPK in remediating leaf iron chlorosis in peanut pot-grown in calcareous soil. The study suggested that Fe–citrate–NPK should be considered as a potential tool for correcting peanut iron deficiency in calcareous soil.