3个群体方斑东风螺线粒体COI基因的遗传多样性分析

为优化方斑东风螺 (Babylonia areolata) 健康养殖技术,比较分析了方斑东风螺稚螺在5种底质环境下 (河砂、棕色陶粒、黑色陶粒、黄色陶粒、白色陶粒) 的生长、壳色及抗氧化性能差异。结果表明,河砂组中底质氨氮 (Babylonia areolata, we compared and analyzed its growth, shell color and antioxidant properties under five substrate environments (River sand, brown ceramsite, black ceramsite, yellow ceramsite, white ceramsite). The results indicat that the ammonia nitrogen content in the river sand group [(0.382±0.010) mg·L⁻¹] was significantly higher than that in the other groups (P<0.05). The highest survival rate was observed in brown ceramide group [(62.00±2.00)%], which was significantly higher than that of river sand group [(56.00±1.00)%], yellow ceramides group [(48.00±2.00)%] and white ceramides group [(42.50±3.00)%] (P<0.05). The shell height, shell width and body mass in river sand group were significantly higher than those in black, yellow and white ceramides groups (P<0.05). At the end of the experiment, the values of lightness, redness and yellowness of shell color in brown ceramide group were significantly higher than those in the other groups (P<0.05). The total antioxidant capacity (T-AOC) in brown ceramide group was significantly higher than that in the other groups (P<0.05). However, the catalase (CAT) activity and malonaldehyde (MDA) content were lower than those in the other groups, with (12.614±0.378) U·mg⁻¹ and (1.179±0.001) nmol·mg⁻¹, respectively. In conclusion, substrate environment can significantly affect the growth, shell color, and antioxidant performance of juvenile B. areolate, and brown ceramide can be selected to replace river sand as the substrate in its farming.     

不同引证主体的专利引文实证比较研究——以5G通信技术领域为例

[目的/意义]目前对专利引文数据的挖掘已被广泛研究应用,此类研究对了解产业演化规律,发现新兴技术机会均有重要意义.为此,本研究是基于对专利的引用主体、引用背景等要素的深入理解上进行.[方法/过程]以第五代移动通信技术(5G)的高被引专利为对象,在德温特专利数据库获取其审查员引文和申请人引文数据.利用定量分析和社会网络分...     

不同养殖水色对红螯螯虾稚虾存活、生长和体色的影响

以经过曝气的透明自来水为养殖水体作为实验对照组,通过添加人工色素调控养殖水色(黄色、蓝色、绿色),探究了养殖水色对红螯螯虾(Cherax quadricarinatus)稚虾存活、生长和体色的影响.结果显示,对照组、黄色和蓝色实验组的成活率均约50％,绿色实验组的较低(33.33％,P<0.05).绿色实验组的增重率、...     

Effects of low salinity exposure on immunological,physiological and growth performance in Litopenaeus vannamei

Growth, immunological and physiological parameters of white shrimp Litopenaeus vannamei reared at different salinity levels (1, 10, 15, 25 and 35 g/L) at stocking density of 214 shrimp/m³ were examined at 1, 30 and 63 days. Results showed that the total haemocyte count (THC) of shrimp decreased with time at all salinity levels, indicating a potential reduction in the resistance of shrimp against pathogens, since a low value of THC indicates a perturbation of the immune system. Glucose and protein values observed in the haemolymph throughout the study indicate that shrimp adapted well to low salinities (1, 10 and 15 g/L). Although of those shrimp reared at 10 g/L only 83.3% survived, at this salinity, shrimp depicted a higher glucose concentration in haemolymph at the beginning and end of the study.     

Effects of PAH-Contaminated Soil on Rhizosphere Microbial Communities

Bacterial associations with plant roots are thought to contribute to the success of phytoremediation. We tested the effect of addition of a polycyclic aromatic hydrocarbon contaminated soil on the structure of the rhizosphere microbial communities of wheat (Triticum aestivum), lettuce (Lactuca sativa var. Tango), zucchini (Cucurbita pepo spp. pepo var. Black Beauty), and pumpkin (C. pepo spp. pepo var. Howden) 16S rDNA terminal restriction fragment length polymorphism (T-RFLP) profiles of rhizosphere microbial communities from different soil/plant combinations were compared with a pairwise Pearson correlation coefficient. Rhizosphere microbial communities of zucchini and pumpkin grown in the media amended with highest degree of contaminated soil clustered separately, whereas communities of these plants grown in unamended or amended with lower concentrations of contaminated soil, grouped in a second cluster. Lettuce communities grouped similarly to cucurbits communities, whereas wheat communities did not display an obvious clustering. The variability of 16S rDNA T-RFLP profiles among the different plant/soil treatments were mostly due to the difference in relative abundance rather than presence/absence of T-RFLP fragments. Our results suggest that in highly contaminated soils, the rhizosphere microbial community structure is governed more by the degree of contamination rather than the plant host type.     

Comparison of three dielectric moisture sensors for measurement of water in saline sandy soil

The number of sensor types available for measuring soil water content has increased but investigations to compare their performance in saline soils needs clarification. In this study the performance of commercially available, low-cost soil moisture sensors [time domain reflectometry (TDR), PR1 and WET], all measuring changes in the dielectric constant of the soil water, was evaluated under laboratory conditions in a saline sandy soil. The three sensors were also tested in the same sandy soil growing drip irrigated sorghum ( Sorghum bicolor L. cv. Moench) in a greenhouse. Plants were irrigated daily with either saline water (ECw: 9.4 dS/m) or fresh water (0.11 dS/m). The volume of irrigation was equivalent to 100% of the pan evaporation. The results showed that measurement accuracy was strongly dependent on the salinity of the soil. The PR1 sensor overestimated volumetric water content ( θ ) when the salinity level exceeded 4 dS/m [root mean square of the standard error (RMSE) = 0.009 cm³/cm³]. The WET sensor significantly overestimated θ irrespective of the salinity level (RMSE = 0.014 cm³/cm³). The TDR sensor estimated θ with more accuracy (RMSE = 0.007   cm³/cm³) and thus can be considered as more reliable than the other two sensors. The calibrations were strongly affected by the salinity level of the water, so we recommend that calibration equations are modified to take account of salinity.     

Genetic diversity and phylogenic relationships in date-palms (Phoenix dactylifera L.) as assessed by random amplified microsatellite polymorphism markers (RAMPOs)

Random amplified microsatellite polymorphisms (RAMPOs) were used to assess genetic diversity among 30 date-palm cultivars and 10 male trees. Using 18 primers combinations, 197 bands were scored and 186 were polymorphic suggesting the high level of polymorphism among studied cultivars. Moreover, taking into account the high percentage of polymorphic bands (ppb), the resolving power (R_p) together with the polymorphism information content (PIC) scored values, all the tested primer sets contribute strongly in the discrimination of date-palm genotypes. In addition, the topology of the derived UPGMA dendrogram exhibited cultivars’ clustering made independently both from the geographical origin and/or from the sex of trees. The present data support the Mesopotamian origin of the date-palm domestication. Thus we assume that the used method is efficient to assess genetic diversity within date-palm cultivars. Data are discussed in relation with the opportunity of the RAMPO method to provide additional molecular markers suitable in the improvement of the date-palms germplasm characterisation.     

Real‐time quantitative PCR‐based detection of Coxiella burnetii in unpasteurized cow's milk sold for human consumption

Coxiella burnetii is a zoonotic pathogen with a worldwide distribution that is responsible for Q fever in humans. It is a highly infectious bacterium that can be transmitted from cattle to humans through the consumption of unpasteurized milk. We report the molecular identification of C. burnetii in raw cow's milk being sold directly for human consumption in Brazil without official inspection or pasteurization. One hundred and twelve samples of raw milk were analysed by real‐time quantitative PCR (qPCR), and C. burnetii was detected in 3.57% (4/112) of the samples at a concentration ranging from 125 to 404 bacteria per millilitre. The identification of this zoonotic pathogen in raw milk sold directly for human consumption is a public health concern since C. burnetii can be transmitted through the oral route. This result indicates that health education and other preventive measures should be officially implemented in Brazil to prevent the spread of infection. To our knowledge, this is the first qPCR‐based detection of C. burnetii in raw milk samples from cows sold in Brazil that do not undergo official inspection or pasteurization.