Milk vetch dwarf virus infection in the Solanaceae and Caricaceae families in Southeast Asia

Milk vetch dwarf virus (MDV) is an important member of the genus Nanovirus and is transmitted by the aphid Aphis craccivora. MDV has multiple single-stranded DNA genome components, each approximately 1 kb, and two or three alpha-satellite molecules. It mainly infects plants of the legume family Fabaceae. Recently, papaya (Carica papaya) collected in Yesan, South Korea, displaying symptoms of leaf yellowing and dwarfism, was identified as a new host for MDV. To examine the geographical distribution of MDV, papaya samples with symptoms were harvested in South Korea, Vietnam, and Taiwan in August 2018, along with tomato and pepper samples grown in adjacent fields in Vietnam. The results revealed the presence of MDV not only in papaya but also in pepper and tomato. This MDV infection in members of the Solanaceae family was confirmed by Southern blot hybridization performed using a PCR product of segment S as a probe. Based on sequence analysis of three MDV components (M, S, and C3), we verified the presence of three different isolates of MDV in these three countries and homology between sequences of isolates from papaya and from members of the Solanaceae from Vietnam. Taken together, our results clearly demonstrate MDV infection in Vietnam and Taiwan for the first time and confirm that MDV can infect economically important pepper and tomato.     

The origin of the turtle body plan: bridging a famous morphological gap

A restudy of pareiasaurs reveals that these primitive reptiles are the nearest relatives of turtles. The two groups share numerous derived characters, such as a reduced presacral count, an acromion process, and a trochanter major, which are absent in other basal amniotes. Many traits long thought specific to chelonians also occur in pareiasaurs and must have evolved before the distinctive turtle shell appeared. Evidence uniting captorhinid or procolophonoids with turtles is shown to be weak. The phylogeny proposed here also suggests that certain features of the earliest turtle (Proganochelys) that have been interpreted as specializations, such as the large supratemporal and robust metacarpals, are primitive for turtles. In pareiasaurs, the osteoderms represent the precursors of the chelonian shell and the morphology of the anterior region is consistent with the idea that the shoulder girdle in turtles has migrated posteriorly into the rib cage.     

Fish population and behavior revealed by instantaneous continental shelf-scale imaging

Until now, continental shelf environments have been monitored with highly localized line-transect methods from slow-moving research vessels. These methods significantly undersample fish populations in time and space, leaving an incomplete and ambiguous record of abundance and behavior. We show that fish populations in continental shelf environments can be instantaneously imaged over thousands of square kilometers and continuously monitored by a remote sensing technique in which the ocean acts as an acoustic waveguide. The technique has revealed the instantaneous horizontal structural characteristics and volatile short-term behavior of very large fish shoals, containing tens of millions of fish and stretching for many kilometers.     

The electron-pairing mechanism of iron-based superconductors

The past three years have witnessed the discovery of a series of novel high-temperature superconductors. Trailing behind the cuprates, these iron-based compounds are the second-highest-temperature superconducting material family known to date. Despite the marked differences in the chemical composition, these materials share many properties with the cuprates and offer the hope of finally unveiling the secret of high-temperature superconductivity. The main theme of this review is the electron-pairing mechanism responsible for their superconductivity. We discuss the progress in this young field and point out the open issues.     

利用卫星遥感进行加拿大花旗松林虫害监测的研究

森林虫害监测是森林经营管理中的一个重要内容,为此作者利用陆地卫星第5号的主题成图仪数据,在加拿大不列颠哥伦比亚省卡奇河试验区对花旗松林被云杉茅卷蛾危害的状况进行了监测。试验表明,在直方均衡的基础上进行比值处理和最大概似分类,其图象处理效果比较理想。利用直升飞机航空目视调查所勾绘的虫害分布图进行对照检验,其位置和形状基本吻合,面积也达到一定的精度。这种分析方法所取得的结果,可作为虫害防治的依据。     

丹参抗氧化成分及其分布特征

借助超声波萃取法，以反相高效液相色谱（RP－HPLC－DAD）为分析检测手段，研究了丹参6种抗氧化成分的提取方法和分离定量条件，并对这些成分在全株丹参不同部位中的含量分布特征进行了探讨，结果表明：常温下的超声波萃取可避免热解作用给丹参酮类化合物带来的损失，布辅助的加热处理可使原儿茶醛获得较高的提取率，两种操作方法简单可行，6种化学成分在丹参不同部位及不同等级中的分布有较大差异，丹参酮类化合物主要分布在根部皮层，而叶子中丹参素的含量却较为丰富，可为丹参品质鉴定和质量标准研究及该资源的综合利用奠定理想基础。     

Radiation-Induced Breeding in Camelina Sativa

Journal of Crop Science and Biotechnology - The ionizing radiation methods, including X-rays, gamma rays, and neutrons to create variation is well established and used in major crops. Many...     

Mechanical properties and water purification characteristics of natural jute fiber-reinforced non-cement alkali-activated porous vegetation blocks

This study reports the effects of the volume fraction of natural jute fiber and the content of the alkali activator on the physical and mechanical properties, sulfate ion resistance, and water purification characteristics of non-cement porous vegetation blocks. The volume fractions of the natural jute fiber were 0.0, 0.1, and 0.2 %, and the alkali activator was applied by replacing 5, 6, 7, 8, 9, and 10 % by weight of the blast-furnace slag. Void ratio, compressive strength, sulfate resistance, and water purification characteristics were characterized. The results indicate that increasing natural jute fiber and the alkali activator content increased the void ratio and improved compressive strength and sulfate resistance. pH was not affected by natural jute fiber content but increased with alkali activator content. At alkali activator contents of 9–10 %, the observed compressive strength was similar to that of cement blocks, whereas mixes with alkali activator contents of 8–10 % showed similar or greater void ratios than those of cement blocks. The compressive strength of the cement blocks decreased following immersion in sulfate solutions; however, the compressive strength of the mixes with the alkali activator and blast-furnace slag increased following exposure to sulfates. Water purification characteristics were examined by allowing water to filter through the blocks; the non-cement porous vegetation blocks reduced the suspended solids, 5-day biological oxygen demand, chemical oxygen demand, total nitrogen, and total phosphorous in the water by >40 %.