Prevalence and pathogenicity of anoplocephala perfoliata in a horse population in South Auckland

A survey of the prevalence of A noplocephala perfoliata in 65 horses is described. An overall prevalence rate of 82% was found for A. perfoliata infection and 77% of infected horses exhibited ulcerative pathology in the ileo-caecal region directly associated with this parasite. Anoplocephela magna and Paranoplocephala mamillana were not recovered.     

Natural occurrence of fumonisins B(1) and B(2) in domestic maize of Taiwan.

Samples of maize grown in various districts of Taiwan were collected and analyzed for the presence of fumonisin B(1) (FB(1)) and fumonisin B(2) (FB(2)) using high-performance liquid chromatography. Forty-nine (44.5%) and 2 (1.8%) of 110 samples were found to contain FB(1) (109-1148 ng/g) and FB(2) (222-255 ng/g), respectively. The frequency of detection and also the maximum FB(1) concentration were found in samples from Penton (2/2, 262 ng/g), followed by Chiayi (18/26, 264 ng/g), Tainan (8/16, 160 ng/g), Hualinen (5/14, 1148 ng/g), Taitung (7/20, 109 ng/g), and Yunlin (9/26, 361 ng/g). Of the 110 samples examined, only 2 samples from Hualinen had been detected containing FB(2). During an analysis of the distribution pattern of FB(1), it became apparent that >79% of tested samples had FB(1) concentrations <100 ng/g, whereas 2.7% (or 3 samples) contained FB(1) >300 ng/g. These results clearly illustrated that domestically produced maize for human consumption is frequently contaminated with FB(1).     

冬小麦性状遗传力的初步研究

本试验采用遗传变量和表现型变量的比值来估算性状的广义遗传力。估算结果以抽穗期的遗传力最高,达72.04%,一株穗数最低,仅25.57%。穗长、株高、千粒重的遗传力分别为69.21%,66.45%和57.55%。其他性状的遗传力则较低。根据遗传力的估值,对各组合的生产力进行了鉴定。试验指出双亲之一如对当地环境条件很不适应,则遗传力误差很大。双亲如均能适应当地环境条件,则遗传力又可能随双亲的差距而递增。利用变异系数的平方代替相应的变量来估算广义遗传力可以起到一定的矫正作用。     

Proteomic study of biocontrol mechanisms of Trichoderma harzianum ETS 323 in response to Rhizoctonia solani

To elucidate the entire range of proteins that are secreted by Trichoderma harzianum ETS 323 in its antagonism with Rhizoctonia solani, an in vivo interaction between them was mimicked and not only the secreted cell wall-degrading enzymes (CWDEs) but also all of the proteome were investigated. Seven CWDEs, chitinase, cellulase, xylanase, beta-1,3-glucanase, beta-1,6-glucanase, mannanase, and protease,were revealed by activity assay, in-gel activity stain, 2-DE, and LC-MS/MS analysis. Extracellular protein extracts from media that contained R. solani exhibited much higher CWDE activities than media that did not contain R. solani. Cellulase and mannanase activity, however, were insignificant. Activity stain also revealed that beta-1,3-glucanase, beta-1,6-glucanase, and xylanase activity occurred exclusively in media that contained R. solani. Furthermore, 35 of the 43 excised spots on the 2-DE gel were successfully analyzed by LC-MS/MS, and eight proteins were identified. They were two glycoside hydrolases, two proteases, two beta-glucosidases, one endochitinase and, interestingly, one amino acid oxidase. Additionally, a possible mechanism was proposed to elucidate how the cell walls of R. solani are systematically enveloped and disintegrated.     

Spin-torque switching with the giant spin Hall effect of tantalum

Spin currents can apply useful torques in spintronic devices. The spin Hall effect has been proposed as a source of spin current, but its modest strength has limited its usefulness. We report a giant spin Hall effect (SHE) in β-tantalum that generates spin currents intense enough to induce efficient spin-torque switching of ferromagnets at room temperature. We quantify this SHE by three independent methods and demonstrate spin-torque switching of both out-of-plane and in-plane magnetized layers. We furthermore implement a three-terminal device that uses current passing through a tantalum-ferromagnet bilayer to switch a nanomagnet, with a magnetic tunnel junction for read-out. This simple, reliable, and efficient design may eliminate the main obstacles to the development of magnetic memory and nonvolatile spin logic technologies.     

Vine cuttings as possible initial inoculum sources of Ralstonia solanacearum race 1 biovar 4 on vegetable sweet potato in fields

Ralstonia solanacearum, which consists of five races/biovars, is considered a “species-complex” and is an important phytopathogen that causes wilt disease in more than 200 plant species. R. solanacearum race 1 biovar 4 (R1bv4) has caused yield losses of 30–80 % in the vegetable sweet potato (VSP) in the last decade in Taiwan. To identify the source of the initial inoculum of R1bv4 in VSP fields, soil and cuttings from these fields were examined from 2009 to 2010. The results of the investigation indicated that the population of R1bv4 was generally distributed throughout the natural soil of VSP fields at a density ranging from 1.3?×?10² to 9.5?×?10⁵ cfu/g soil; however, the incidence of bacterial wilt was not significantly associated with the density of the R1bv4 population in soils (R²?=?0.084). In contrast, densities of R1bv4 ranging from 2.3?×?10³ to 5.9?×?10⁵ cfu/g tissue were detected in the vine tissue of asymptomatic plants in the fields. Additional experiments demonstrated that R1bv4-free VSP cuttings without visible symptoms planted in infested soils in the greenhouse setting could carry approximately 3.1?×?10⁵ R1bv4 cfu/g tissue, which suggests the existence of a latent period for R1bv4 in VSP plants. The results of a BIO-PCR analysis showed that R1bv4 was detected in 2.0 to 98.0 % of the VSP cuttings used for propagation in fields; in addition, the percentage of VSP cuttings carrying R1bv4 and the incidence of bacterial wilt in fields were positively correlated (R²?=?0.909). The inoculation experiments conducted in greenhouses and in fields showed that the cutting inoculum (CI) contributed more to the incidence of bacterial wilt in VSP plants than the soil inoculum (SI). In the field experiments conducted in 2010, an incidence of disease of 27.1 to 38.5 % was detected in healthy field cuttings 8 months after transplantation; in contrast, the incidence of disease in field cuttings carrying R1bv4 was 49.0 to 68.8 %. The incidence of disease was significantly lower in healthy cuttings than in cuttings carrying R1bv4 (p?=?0.05).     

Genetic Diversity Among Brazilian Cultivars and Landraces of Tomato Lycopersicon Esculentum Mill. Revealed by RAPD Markers

Random amplified polymorphic DNA markers (RAPD) were used to estimate the variability of 35 tomato accessions (Lycopersicon esculentum Mill.). A total of 257 reproducibly scorable bands were obtained from 20 primers, 78.6% of which were polymorphic. The percentage distribution of RAPD markers shows a bimodal distribution, and the frequency of rare alleles is similar in commercial and landrace accessions. Genetic distances among accessions were calculated and a dendrogram showing the genetic relationships among them was constructed allowing for the separation of four groups. Twenty out of 23 Brazilian landraces fell within one group, whereas commercial cultivars were distributed in the four groups. AMOVA analysis of RAPD data showed that, despite the high within Brazilian landraces and commercial cultivars variation, these two groups are significantly different, indicating that landraces can be a source of variation for breeding programs.