Experimental infection of pigs with different doses of the African swine fever virus Armenia 07 strain by intramuscular injection and direct contact

We experimentally infected pigs with the African swine fever virus (ASFV) Armenia 07 strain (genotype II) to analyze the effect of different dose injections on clinical manifestations, virus-shedding patterns, histopathology, and transmission dynamics by direct contact. Each three pigs and four pigs were injected intramuscularly with 0.1 fifty percent hemadsorbing doses (HAD₅₀)/ml, 10¹ HAD₅₀/ml and 10⁶ HAD₅₀/ml of ASFV Armenia 07 strain, respectively. Each two of three pigs injected with 0.1 HAD₅₀/ml and 10¹ HAD₅₀/ml died by 10 days post inoculation. All pigs had a gross lesion of splenomegaly. Perigastric and renal lymph nodes were enlarged and resembled blood clots in nine of ten pigs. It was revealed that 0.1 HAD₅₀/ml of this ASFV was sufficient to infect healthy pigs by intramuscular injection and caused sub-acute lethal disease. For the transmission study, two 8-week-old pigs were injected intramuscularly with 10³ HAD₅₀/ml of the same virus. Each of the experimentally inoculated pigs was co-housed with two 8-week-old naive pigs. All contact pigs exhibited clinical manifestations at 6 or 7 days after the experimentally inoculated pigs developed pyrexia. These findings suggest that this strain may spread slowly within a herd. Histologically, lymph nodes resembled blood clots were formed by severe blood absorption and followed hemorrhage result of disruption of the lymphoid sinus filling with absorbed red blood cells. The severity of the gross and histological lesions depended on duration after infection, regardless of the difference of injection doses in this study.     

A novel blast resistance locus in a rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) cultivar,Chumroo, of Bhutan

The rice cultivar ‘Chumroo’ is commonly cultivated in the mid- and high-altitude areas of Bhutan. This cultivar has shown durable blast resistance in that area, without evidence of breakdown, for over 20 years. Chumroo was inoculated with 22 blast isolates selected from the race differential standard set of Japan. The cultivar showed resistance to all the isolates. To identify the resistance gene(s), Chumroo was crossed with a susceptible rice cultivar, Koshihikari. The F₁ plants of the cross showed resistance. Segregation analyses of 300 F₃ family lines fitted the segregation ratio of 1:2:1 and indicated that a single dominant gene controls the resistance to a blast isolate Ao 92-06-2 (race 337.1). The Chumroo resistance locus (termed Pi46(t)) was mapped between two SSR markers, RM6748 and RM5473, on the terminal region of the long arm of chromosome 4, using linkage analysis with SSR markers. The nearest marker, RM5473, was linked to the putative resistance locus at a map distance of 3.2 cM. At the chromosomal region, no true resistance genes were identified, whereas two field resistance genes were present. Therefore, we designated Pi46(t) as a novel blast resistance locus.     

Changes in esculeoside A content in different regions of the tomato fruit during maturation and heat processing

We previously demonstrated that esculeogenin A, a new aglycone of the tomato sapogenol esculeoside A, inhibits both acyl coenzyme A:cholesterol acyl-transferase (ACAT)-1 and -2 and ameliorates the pathogenesis of atherosclerosis in apoE deficient mice. Although we believe that daily intake of esculeoside A from tomato products can play a beneficial role in preventing the pathogenesis of atherosclerosis, the compound is not being used for preventive medicine due to the lack of information on methods for quantitative analysis and the content and stability of the compound in tomato products. In the present study, we report the development of a high-performance liquid chromatography (HPLC) method using an instrument equipped with a refractive index (RI) detector for esculeoside A quantification. We used this method to measure the changes in esculeoside A content during maturation, its distribution in the fruit body, and its stability during the heating process. The contents of esculeoside A in cherry tomatoes and Momotaro tomatoes were 21- and 9-fold, respectively, higher than that of lycopene, which is the most well-known compound in tomatoes. Furthermore, the esculeoside A content in pericarp wall was higher than in the whole tomato fruit and increased in a time-dependent manner during maturation. Although the melting point of purified esculeoside A was 225 °C, the esculeoside A in crude tomato extract decreased in a temperature-dependent manner. Degradation due to the heating process was inhibited under a pH of 9. These results demonstrated that the esculeoside A content differs in the various types of tomatoes, during maturation, and during the heating process used for preservation.     

杭州地区田间稻纵卷叶螟对不同组分雌性外激素的趋性

 :1998～ 1999年 ,分别用日本、菲律宾和印度种群雌性外激素组分特征的性诱剂在中国浙江省杭州进行了稻纵卷叶螟 ( Cnphalocrocismedinalis)的性诱剂田间诱捕试验。研究发现 ,具有日本种群雌性激素组分特征的性诱剂对雄性稻纵卷叶螟的诱集效果好 ,其他性诱剂与之相比差异显著     

Quantitative relationship between soil properties and adsorption of dissolved organic matter onto volcanic ash and non-volcanic ash soils

The formation of soil organo-mineral complexes is a key reaction in the carbon cycle in soil, since organic materials acquire a resistance to decomposition due to the formation of the complexes. Adsorption of dissolved organic matter (DOM) onto soil minerals provides a model of this important process. Adsorption of DOM onto samples from Andisols, Inceptisols, and Entisols in batch experiments was compared in terms of the quantitative relationship between the soil properties and the adsorption behavior of DOM. Adsorption behavior was effectively described by a linear initial mass (IM) isotherm, indicating that the adsorption efficiency did not appreciably decline in the range studied even though a large amount of DOM was applied to the soil samples. Samples from Andisols showed a particularly high efficiency of adsorption compared with those from other soils which contained a comparable amount of organic carbon. Explanatory variables useful to predict the efficiency parameter were investigated in 2 steps: firstly the degree of carbon accumulation in the soil samples was examined, and next an index for the amount of ligand exchange sites was examined in combination with the former indices. As a result, an index comprising the total carbon/clay (or total carbon/specific surface area) ratio and the amount of hydroxy ions in the soil extracts with NaF solution was eventually detected. The former represents the degree of carbon occupation on the soil surface, and the latter the amount of ligand exchange sites on labile aluminum. Although the mechanisms involved in the adsorption varied among soils, the selected index was significantly correlated with the adsorption efficiency.     

Early dispersal of ayu during marine stages as inferred from geographic variation in the number of vertebrae

ABSTRACT:   Marine environments often allow interbreeding of individuals over the species range, and analyses using neutral molecular markers may lose extant genetic boundaries laid between geographic majorities. Ayu Plecoglossus altivelis has a typical amphidromous life history, migrating between rivers and the sea. In order to clarify reproductive elements of the species, migrants from 64 rivers and streams sampled over a wide latitudinal range were examined for their vertebral number (VN) and dorsal pterygiophore number (DPN) as morphological markers to estimate the temperature history. The irregular variability in VN without a geographic cline suggests that the ascending schools of fish are composed of conspecifics sharing incubation temperature or hatching site. The intersample difference in DPN indicates that larvae and juveniles of ayu spend their marine life inside a water body with a distinct temperature. Site tenacity during the marine stage may be helpful to enhance the opportunity to return to the river where they hatched. Each assemblage of fish ascending to rivers and streams is deemed to mostly represent a reproductive element, and therefore, each acts as an evolutionarily significant unit within a metapopulational structure.     

Effect of introducing wild paternity on stock performance of hatchery-reared ayu

The domestication of ayu Plecoglossus altivelis, in which breeding has been carried out for multiple generations without the introduction of exotic broodstock (purebred-styled cultivation), causes rapid loss of genetic variability, and is problematic for resource management programs. The introduction of wild paternity to enhance genetic variability was examined for its effects on the performance of the newly hybridized stock using the Gunma population (hatchery strain), which has been inbred for 29 generations since its origin. Principal component analysis showed that hybridization could modify the stock performance, moderately affecting behavior and morphometrics. Reinforcement of aggressiveness as well as transformation to a long-nosed shape in the hybrid population contribute drevised performance that was acceptable to sports fishers as an artificial stock. To reduce genetic stress for native ayu populations, the introduction of wild paternity is proposed through sperm from wild caught specimens to hybridize with eggs from the pure-bred hatchery population.