Effects of microtopography and erosion on seedling colonisation and survival in the volcano Usu,northern Japan,after the 1977–78 eruptions

The effects of microtopographical characteristics of the thick accumulation of ash and pumice, which were produced from 1977–78 eruptions, on seedling emergence and survival were monitored on the volcano Usu, northern Japan, 10 years after the eruptions. The characteristics included microtopography, texture of volcanic deposits on ground surface, volcanic‐deposit movements, water content on ground surface and chemical nature of volcanic deposits (ignition loss, P, K and pH). Polygonum sachalinense showed a higher seed germination percentage on finer‐particle ground surface under lab conditions, and Petasites japonicus var. giganteus germinated well on the ground surface with any particle sizes. However, in the field, the seedling densities of those two species and Anaphalis margaritacea var. angustior (three dominant species in this region) were higher on the sites with coarse particles and/or the rill inside the crater basin. The seedling germination timing and space overlapped among these species in the field. Those facts suggested that the seedling colonisation pattern was influenced more by the topographical characteristics of ground surface rather than the germination abilities. The amount of organic matter in the volcanic deposits was very low, even 11 years after the eruptions, and was not related to microtopography, suggesting that the effects of organic matter on seedling emergence did not differ along microtopographical characteristics. Inside of rills, higher water content seemed to be more advantageous for seed germination of those species. Volcanic deposits were physically stable in summer, but were heavily eroded after winter due to snowmelt. Most seedlings did not overwinter in the inside of rills with pumice where the volcanic deposits eroded intensively, indicating that the patterns of land degradation by melting snow should be mentioned carefully even with narrow scale. Copyright © 2007 John Wiley & Sons, Ltd.     

Plot location errors of National Forest Inventory: related factors and adverse effects on continuity of plot data

Plot location errors (distance between recorded and true coordinates) of National Forest Inventory (NFI) cause a mismatch between plot data and remotely sensed data and might prevent re-measurement because plots with large location errors are hard to find. However, few studies have examined the detailed distribution of errors and related factors, and no studies have verified whether the large errors prevent re-measurement. This study analyzed data related to 101 plots in central Japan that had been established by the First NFI (1999–2003) on a 4-km grid. Plot location errors of these plots were measured by revisiting. Selective Availability (SA) of the Global Positioning System, which degraded location accuracy until May 2000, was the most important factor in increasing plot location errors. The mean errors were 58.6 and 15.0 m, with and without SA, respectively. In 12 plots with large plot location errors (the mean error was 84.6 m), re-measurement in the Second NFI (2004–2008) was not conducted because plot locations could not be found. In these situations, alternative new plots were established; however, their species compositions were significantly different from the initial NFI plots. Plot location errors of NFI adversely affect the continuity of plot data as well as the analysis with remotely sensed data.     

Rapid and convenient method for preparing aurapten-enriched product from hassaku peel oil: implications for cancer-preventive food additives

Aurapten (7-geranyloxycoumarin) has been reported to be an effective inhibitor of chemical carcinogenesis in some rodent models. In the present study, a method for preparing an aurapten-enriched agricultural product has been established. Out of 17 Rutaceae varieties, the aurapten content in hassaku (Citrus hassaku Hort ex Y. Tanaka) fruit peel was marked, as well as that in natsumikan (C. natsudaidai) and grapefruit (C. paradisi). The aurapten content in hassaku peel was most abundant in April. Hassaku fruit peel oil, which was dissolved by heating precipitates including aurapten which had formed after freezing the peel oil at -20 degrees C, was used. After adsorbing aurapten from peel oil onto synthetic adsorbent SP70, the adsorbent was washed with 40% (v/v) ethanol in water to remove essential oils and pigments remaining on the adsorbent. Aurapten was then eluted with 80% (v/v) ethanol. In a laboratory-scale test, the recovery rates of aurapten and total carotenoids from the eluates were 74.3 and 4.6%, respectively. In a pilot-scale test, the recovery rate of aurapten in the aurapten-enriched preparation from dissolved hassaku oil was 91.0%, and its concentration was 64.1% (w/w). When stored for 180 days under sunlight, aurapten in powder form remained at 88.0-89.0% of the initial level, but only 31.3-43.8% in ethanol. The stability of aurapten in the aurapten-enriched preparation was higher than that of purified aurapten. These results suggest that aurapten is readily recovered from hassaku peel oil using SP70, and thus may be used as a food additive.     

Changes in Chemical Species of Copper Added to Brown Forest Soil in Japan

Heavy metals are present as various chemical species in soil environments. Chemical species of heavy metals determinate their behavior in soil, so they must be more important concern than total contents in treating problems about heavy metal polluted soil. Microbial activity is thought to be one of the factors that affect chemical speciation of heavy metals. Although some possible microbial mechanisms have been suggested, their effects on heavy metals have not previously been thoroughly studied. In this study, we investigated whether microorganisms contribute to the fractionation of Cu in a forest soil. Copper-enriched, sterilized forest soil samples were buried at their places of origin, and subsamples were collected for analysis 3, 10, 17, 30, 60, and 90 days after burial. Tessier’s sequential extraction was employed to analyse Cu fractionation. Until two months after burial, the added Cu remained nearly unchanged. But a dramatic change was found in soil subsamples after three months. In both the A and B horizons, the carbonate fraction of Cu increased and the residual fraction decreased. We also found that clay minerals and persistent organic matter are important binding substances of Cu in the residual fraction. The change from residual to carbonate fraction could be caused by microbial activity.     

Attributes of stand-age-dependent forest determine technosol fertility of Atlantic forest re-growing on mining tailings in Mariana,Brazil

Understanding how soil fertility changes due to environmental conditions and stand-age-dependent for-est attributes is important for local-scale forest restoration.We evaluated the effects of stand-age-dependent forest attributes (plant community composition and litter stock)on soil and technosol fertility across two second-growth Atlantic forests (SGF) after the deposition of mining tail-ings in Mariana,southeastern Brazil.We hypothesized that technosol fertility in the SGF tailings is positively affected by plant community composition variability,stand age,and litter stock.We used total exchangeable bases and organic matter as fertility indicators for technosol and soil,and spe-cies composition and litter stock as stand-age-dependent forest attributes.Our results showed significant differences in the stand-age-dependent forest attributes and soil chemi-cal properties between the two forest patches (SGF tailing and SGF non-tailing) evaluated.Thus,there was a marked gradient of litter storage and fertility between soil and tech-nosol that can be important forest recovery indicators for the affected plant communities.Furthermore,according to the tested models,we corroborated the hypothesis that techno-sol fertility is positively affected by stand age,plant com-munity composition variability,and litter stock,which may contribute considerably to forest recovery on tailings.Our results demonstrate that the fertility predictors analyzed to explain the forest recovery on tailings can also be considered as ecological indicators for assessing forest restoration in areas impacted by mining tailings in Mariana.     

Hemolytic activity of Akabane virus

Akabane virus was shown to lyse as well as to agglutinate pigeon erythrocytes. The hemolytic activity of the virus was markedly enhanced by repeated freeze-thawing, but its hemagglutinating activity was not affected. Hemolysis (HL) with the virus, like its hemagglutination, was affected by the NaCl concentration as well as by the pH of the diluent. HL was markedly affected by the incubation temperature, but hemagglutination (HA) was not; HL activity was highest at 37°C, somewhat lower at 25°C, very low at 4°C, and did not occur at 0°C. While pigeon erythrocytes were positive for both HL and HA, goose erythrocytes were positive for HA but negative for HL. Erythrocytes from cattle, sheep, rabbits, guinea pigs, mice and day-old chickens were tested for HA as well as for HL activity with negative results. A linear relationship was shown, in a wide range of the virus concentrations, between the percent HL and the virus concentration, as expressed on a logarithmic scale. Based on these findings we developed an assay method for Akabane virus hemolysin. Analysis by CsCl equilibrium density gradient centrifugation indicated the hemolytic as well as the hemagglutinating activity to be structurally associated with the virion. Scanning electron microscopy of pigeon erythrocytes undergoing HL with the virus revealed the appearance of a depressed area with a hole on the cell surface. The hemolytic activity of the virus was specifically inhibited by antisera to the virus and an HL-inhibition test was developed.     

Isolation and characterization of Shiga toxin-producing Escherichia coli O157:H7 from beef,pork and cattle fecal samples in Changchun,China

Meat samples and fecal specimens from adult cattle were collected in Changchun, China and were examined for presence of Shiga toxin-producing Escherichia coli (STEC) serogroup O157. STEC O157 strains were isolated from 2 (5%) of 40 beef, 1 (3.3%) of 30 pork, and 3 (1.7%) of 176 adult cattle fecal samples. The strains belonged to phage types (PT) 4, 8, or 47. Two beef strains and a strain previously isolated from a patient in Shandong, China, were PT-4 and showed a similar PFGE pattern, suggesting the possibility of food-borne transmission. It is suggested that cattle are a reservoir of STEC O157:H7 and meat products are contaminated by this pathogen in Changchun, China as well as in other countries.     

Effects of epidermal growth factor on placental amino acids uptake in pregnant rats

To evaluate the effects of epidermal growth factor (EGF) on placental amino acids uptake, transport activities for L-proline, L-leucine, and L-alanine were kinetically examined in placental microvillous vesicles(PMV) obtained from pregnant rats administered with EGF(100 and 200 microg/kg/day) from day 18 to 21 of pregnancy. The Vmax of Na(+)-dependent proline uptake remarkably increased with a dose-dependent manner of EGF, while Km did not change. In contrast, Vmax and Km values of Na(+)-dependent and -independent alanine, and Na(+)-independent leucine uptake were not affected. These results suggested that EGF enhanced proline transport activity in placental microvillous membranes, resulting in an increase of proline concentration in the fetal blood. The selective up-regulation of proline uptake was considered to contribute to fetal growth by EGF.