Comparison of the surface coat proteins of the pine wood nematode appeared during host pine infection and in vitro culture by a proteomic approach

Pine wilt disease, caused by the pine wood nematode (PWN), Bursaphelenchus xylophilus, has become of worldwide quarantine concern in recent years. Here, we disclosed the surface coat (SC) proteins of the PWN which are thought to be one of the key components in pine wilt development. This is the first report that focused on the SC proteins and thoroughly identified those proteins of a plant-parasitic nematode using the proteomic approach. In this study, SC protein profiles were compared for PWNs grown on the fungus Botrytis cinerea and in host pine seedlings. The results demonstrated that the gross amount of PWN SC proteins drastically increased during infection of the host pine. Thirty-seven protein bands showed significant quantity differences between fungus-grown and host-origin PWNs, and were used for identification by matrix-assisted laser desorption ionization time of flight mass spectrometry analysis. These included several proteins that are presumed to be involved in the host immune response; for example, regulators of reactive oxygen species (ROS) and a ROS scavenger. These results might suggest that the PWN SC proteins are crucial in modulating or evading host immune response. Our data provide a new insight into the mechanism of pine wilt disease and the biological role of the SC proteins of plant-parasitic nematodes.     

Changes in fructooligosaccaride composition and related enzyme activities of burdock root during low-temperature storage

Changes in the composition of fructooligosaccarides (FOSs) and related enzyme activities of burdock root during low-temperature storage (1 °C) were measured. Burdock root is composed of monosaccharides, such as glucose and fructose, disaccharides, such as sucrose, and FOS in the extracted carbohydrates. The composition was the highest in fructose, followed by sucrose, FOS, and glucose. The FOS composition was the highest in 1-kestose, followed by nystose and 1-fructofuranosyl nystose. The fructose and glucose contents in burdock root during storage at 1 °C decreased significantly, whereas the sucrose content increased sharply. In contrast, the 1-kestose, nystose, and 1-fructofuranosyl nystose contents significantly increased. The activities of sucrose:sucrose 1-fructosyl transferase (1-SST) and fructan:fructan 1-fructosyl transferase (1-FFT) increased sharply and then gradually decreased, and they were closely related to the changes in FOS content. However, the activity of fructan 1-exohydrolase (1-FEH) was constant. These results indicate that changes in the FOS composition and related enzyme activities of burdock root might be related to low temperature during long term storage.     

Influences of nitrogen and phosphorus addition on polyphenol oxidase activity in a forested Andisol

Increased atmospheric N deposition could suppress plant litter decomposition, due to the P limitation for soil microorganisms in Japanese forested Andisols with a high P sorption capacity. To explore this possibility, we used a laboratory incubation experiment to study the influence of N addition on β-d-glucosidase and polyphenol oxidase activities, which are important for cellulose and lignin degradation, respectively, in an Andisol with larch (Larix kaempferi) leaf litter. The addition of N increased the β-d-glucosidase activity, whereas it decreased the polyphenol oxidase activity in the soil. However, the addition of both N and P increased the polyphenol oxidase activity in the soil, suggesting the possibility of; (1) an inferior competitive ability of polyphenol oxidase-producing microorganisms under nutrient-rich conditions and; of (2) their P limitation through competition in the Andisol.     

Why do trees decline or dieback after a strong wind? Water status of Hinoki cypress standing after a typhoon

We examined the water status of Hinoki cypress, Chamaecyparis obtusa (Siebold & Zucc.) Endl., trees after a severe typhoon to determine possible causes of the decline and dieback that can occur in what appear, at first, to be healthy trees in typhoon-damaged forest stands. We found that in apparently healthy trees in a storm-damaged stand, the water conducting area of the trunk cross section was greatly reduced compared with that of similarly sized trees in a nearby undamaged stand. Although leaf specific hydraulic resistance (Wl) from soil to leaf and from trunk to leaf was higher in trees from the storm-damaged than the undamaged stand, Wl values from soil to root were similar. Diurnal patterns in the rates of change in trunk diameter differed between trees in the damaged and the undamaged stand. We conclude that increased aboveground hydraulic resistance caused by a reduction in trunk water conducting area could be a major reason for the decline and dieback of apparently healthy trees in typhoon-damaged stands.     

Suitability of Japanese codling as a raw material for surimi-based products revealed by primary sequence analysis of myosin heavy chain and thermal gel properties

Fisheries Science - Complementary DNA encoding a part of myosin heavy chain was cloned from fast skeletal muscle of Japanese codling Physiculus japonicus. Japanese codling, a frequent catch off the...     

Spatiotemporal variations in nutritional status and feeding habits of immature female bighand thornyhead <Emphasis Type="Italic">Sebastolobus macrochir</Emphasis> off the Pacific coast of northern Honshu,Japan

Nutritional status and feeding habits of immature female bighand thornyhead Sebastolobus macrochir were assessed based on Fulton’s condition factor K, hepatosomatic index (HSI), and stomach observations. Fish were obtained from bottom trawl samples taken seasonally during 2006/2007 in the Tohoku area, off the Pacific coast of northern Honshu, Japan. Results of the generalized linear model (GLM) indicated that fish condition deteriorated with depth, and small fish had a lower K, HSI, and percent stomach content index (SCI) than larger specimens. The empty stomach rate was higher in deeper waters in northern Tohoku (except for small fish from spring to autumn) and in southern Tohoku (spring/summer). Changes in the index of relative importance (%IRI) showed that the main prey items changed from nutritionally high to low prey items with depth. This suggests that deeper waters, where fish with the lowest condition values occur, are a poorer quality habitat for immature bighand thornyhead and that small fish are subordinate to larger fish. The effect on growth, due to variations in nutritional status and feeding habits, produced by the distributional changes in bighand thornyhead is also discussed.     

Uptake of orally administered polystyrene latex and poly(D,L-lactic/glycolic acid) microspheres into intestinal lymphoid tissues in chickens.

Fluorescein-labeled microspheres were orally administered to chickens and their distribution in intestinal lymphoid tissues was investigated. Polystyrene latex microspheres were observed in Peyer's patches, and also in the Meckel's diverticulum and the jejunum. Their density, however, seemed to be lower than that in Peyer's patches. Microspheres were rarely observed in the other intestinal tissues examined, including the bursa of Fabricius. Of note is that, although microspheres were present in the lumen, few, if any, were observed in the lamina propria of the caecal tonsil and caecum. Polystyrene latex microspheres of diameter 2.0 microm or 4.5 microm were also observed in Peyer's patches, but their density seemed to be lower as compared with the 0.75 microm microspheres. Poly(D,L-lactic/glycolic acid) (PLGA) microspheres were prepared using PLGAs of various molecular weights (MW) and their uptake into Peyer's patches was compared. Microspheres prepared with PLGA of average MW of 20000 were not taken up into Peyer's patches, but those prepared with PLGA of average MW of 61000 or 99 800 were taken up into Peyer's patches.     

Geographical variations in the trophic structure of the plankton community along a eutrophic–mesotrophic–oligotrophic transect

The geographical variations in trophic structure of the plankton community, as defined by total and relative carbon biomass of phytoplankton (PP), bacteria (BA), heterotrophic nanoflagellates (HNF), microzooplankton (MZ), and herbivorous (HNZ) and carnivorous net-zooplankton (CNZ), were investigated along an inshore–offshore transect from the innermost part of Osaka Bay to the Pacific Ocean off Kii Channel, Japan, in June 1991. Based on physico-chemical properties of the water and topographical features, the transect was divided into three trophic areas, i.e. eutrophic, mesotrophic and oligotrophic ones. The average carbon biomass of the total plankton community was highest (438 mg m⁻³) in the inshore eutrophic area, and declined steeply offshore (141 and 26.6 mg m⁻³ in the mesotrophic and oligotrophic areas, respectively). In the offshore oligotrophic area, the relative biomass of BA to PP and the relative biomass of small heterotrophs (i.e. BA, HNF and MZ) to the total heterotrophs were higher than in the other areas, indicating that the microbial food chain predominated. In the mesotrophic area, the biomass of HNZ (primarily copepods) was conspicuously high, even higher than that of PP, suggesting that the traditional grazing food chain prevailed. Because of this short food chain, a productive fishing ground is formed there. In the eutrophic area, the biomass of HNZ was much smaller relative to the enormous biomass of PP, indicating that a considerable amount of primary production was not utilized directly by the metazoan zooplankton. However, the relative contribution of the small heterotrophs to the total heterotrophs' biomass was higher in this area, as in the oligotrophic area.     

常规籼稻与杂交籼稻氮素利用效率的差异

在盆栽条件下 ,研究 1 9个常规籼稻和 1 6个杂交籼稻代表性品种 (组合 )的氮素利用效率的差异。结果表明 :1常规籼稻与杂交籼稻氮的干物质生产效率 (NUEp)及籽粒生产效率 (NUEg)在品种 (组合 )间的变化幅度均较大 ,两者的变异系数均较大 ,但杂交籼稻的变化幅度低于常规籼稻。2无论是常规籼稻还是杂交籼稻 ,NUEp在抽穗至成熟这段时间内均有较大幅度的提高 ,两类籼稻分别提高 2 8.2 %和 1 3 .3 %。 3杂交籼稻的 NUEp在抽穗期高于常规籼稻 ,成熟期则低于常规籼稻 ;而杂交籼稻的 NUEg则比常规籼稻高。4随品种 (组合 )产量水平的提高 ,杂交籼稻及常规籼稻的氮利用效率 (包括 NUEp及 NUEg)下降 ,且变化幅度减小 ,而氮收获指数 (NHI)则有所提高。 5杂交籼稻的产量、物质生产量与抽穗前的吸氮量的相关关系未达显著水平 ,与总吸氮量呈极显著的正相关 ;而常规籼稻的产量及物质生产量与抽穗前的吸氮量及总吸氮量均呈极显著的正相关     

The differences in behavioral responses to a net obstacle between day and night in captive manatees; does entanglement happen at night?

Entanglement in fishing gear occurs in endangered manatees and may result in serious injury or death. Such incidents may happen more frequently at night when the animal’s visual sense is limited. In this study, we examined the differences in behavioral response of captive manatees to a net obstacle during light (day) and dark (night) periods. We used a plastic net as the obstacle, and video-recorded the manatees’ behavior. The experiments showed that captive manatees avoided the obstacle during the day more frequently than at night, which suggests that the manatees can perceive the obstacle more readily during light periods. However, there was no difference in the frequency of bumping or actively touching the obstacle between light and dark periods. The results suggest that the manatees can recognize the net obstacle even at night by purposely touching it, but they avoid it less frequently, and that entanglement during light periods may occur during accidental bumping, rather than from a failure to recognize it altogether.