First report of ophidiomycosis in Asia caused by Ophidiomyces ophiodiicola in captive snakes in Japan

Ophidiomycosis is an emerging infectious disease caused by the fungus Ophidiomyces ophiodiicola, which has been affecting wild and captive snakes in North America, Europe, and Australia. We report 12 cases of suspected ophidiomycosis in captive colubrid snakes in Japan. Pathological and microbiological examinations were performed, and the results confirmed the diagnosis of ophidiomycosis in two snakes, which indicated that the remaining sympatrically raised snakes also had ophidiomycosis since they exhibited similar lesions. This is the first report of ophidiomycosis in Asia caused by O. ophiodiicola. To prevent the expansion of ophidiomycosis in the natural environment in Japan, there is a need to evaluate the ophidiomycosis carrier status of imported snakes, the pathogenicity of the infection in native snakes, and the prevalence and distribution of O. ophiodiicola in wild and captive snakes. Measures also must be taken to prevent endemicity globally.     

Effect of flexible and rigid roughness elements on aeolian sand transport

In developing countermeasures to reduce the negative effects of strong dust events, the fundamental relationship between surface conditions and sand transport remains problematic. We conducted field observations and wind tunnel experiments to examine the effect on sand transport efficiency of actual frontal area when using flexible roughness elements (artificial grass) and rigid roughness elements (tufts of stiff wire). In the field observations, the sand trap ratio approached a limit as the frontal area of artificial grass, measured as the Actual Frontal Area Index (AFAI), approached 25%, equivalent to a vegetation cover of 20%. The wind tunnel experiments showed that the height of deposited sediment decreased downwind with both roughness elements, due to their reduction of both shear velocity and sand transport rates. The sediment flux decreased as the AFAI increased, and the rigid roughness element trapped more sand particles than the flexible one except at higher wind speeds and lower AFAI values. The sand trapping efficiency was greater for rigid roughness elements than for flexible ones, probably due to their high aerodynamic resistance, and thus wire tufts were more effective for trapping sand than artificial grass at higher AFAI values.     

Frequent use of colistin-based drug treatment to eliminate extended-spectrum beta-lactamase-producing <Emphasis Type="Italic">Escherichia coli</Emphasis> in backyard chicken farms in Thai Binh Province,Vietnam

Reports of livestock infections with extended-spectrum beta-lactamase-producing Escherichia coli (ESBL-E) are increasing. Based on interviews conducted over a 6-month period, we found that veterinarians in the Vietnamese province of Thai Binh prefer to prescribe colistin-based drugs (CBD) in chicken farms. We aimed to clarify whether CBD use selects for strains of colistin-resistant ESBL-E. With the cooperation of seven local households, we detected ESBL-E in chickens’ feces after treating chickens with CBD. Phylogenetic groupings and the presence of CTX-M/AmpC genes were determined, and the multi-antibiotic susceptibility of isolates was analyzed. Our results showed that ESBL-E presented in seven chickens’ feces from two households. Seventy-two percent of ESBL-E isolates harbored CTX-M9 and the phylogenetic group A; the colistin minimum inhibitory concentration (MIC) of all isolated ESBL-E ranged from 0.064 to 1 μg mL^?1. Moreover, ESBL-E isolates were used to experimentally select for colistin resistance, and the effect of commercial CBD on ESBL-E was investigated. The results showed that an ESBL-E strain with a colistin MIC of 4 μg mL^?1 was able to grow in media with CBD. Although CBD treatment was effective, in vitro experiments demonstrated that ESBL-E can easily acquire colistin resistance. Therefore, restrictions on colistin use are necessary to prevent the emergence of colistin-resistant bacteria.     

Plasma biochemical reference values in clinically healthy captive bearded dragons (Pogona vitticeps) and the effects of sex and season

Background: Bearded dragons are one of the most popular pet lizard species, and biochemical reference values are useful for health management of these reptiles. Objectives: The objectives of this study were to measure plasma biochemical values in healthy captive bearded dragons, determine reference values, and evaluate the effects of sex and season on the results. Methods: Blood samples were collected from 100 captive healthy bearded dragons in Tokyo during the summer and winter. Plasma biochemical measurements were performed using a dry‐slide automated biochemical analyzer. The data were then compared based on sex and season using 2‐way ANOVA. Results: Globulin, cholesterol, and calcium concentrations of females were higher in both summer and winter compared with the values obtained for males. Both males and females had higher uric acid concentrations in winter than in summer. When compared with males, females had a higher chloride concentration in summer and a higher total protein concentration and aspartate aminotransferase activity in winter. Potassium concentration in males was lower in winter than in summer, whereas in females cholesterol concentration was lower in winter than in summer. Conclusions: Biochemical values that differed based on sex and season in bearded dragons were similar to those in other lizards. These differences reflect physiologic differences in reproductive status in females and seasonal changes in temperature and hydration status. Plasma biochemical values established for bearded dragons in this study will be useful in the diagnostic assessment of captive animals.     

Methane production and its fate in paddy fields

Abstract

Oxidation of methane and total water soluble organic carbon (TOC) in the subsoil, which percolated from the plow layer, was investigated in a column experiment. The amounts of both methane and TOC in the leachate decreased by percolation in the subsoil.

Fe²⁺ percolated from the plow layer was nearly completely retained in the subsoil. The decomposition of methane and TOC in the subsoil was considered to result in the coupling with the formation of Fe²⁺. Methane was estimated to contribute ca. 19–21% to the total amount of Fe²⁺ formed in the subsoil by the organic materials in the leachate.     

Response of differentiated and degenerated spikelets to top-dressing,shading and day/night temperature treatments in rice cultivars with large panicles

The presence of large panicles enables to reach a sufficient number of surviving spikelets per unit area for further increase of rice yield. However, the response of differentiated and degenerated spikelets to environmental factors in terms of number in cultivars with large panicles has not been elucidated. By applying top-dressing at different rates and frequencies, shading, and day/night temperature treatments in pot experiments, we observed the response of the main stem in two cultivars with large panicles: Yangdao 4 (Chinese indica) and Akenohoshi (Japanese japonica-indica hybrid). The results showed that top-dressing increased the number of differentiated spikelets per panicle and decreased the percentage of degenerated spikelets. Consequently, the number of surviving spikelets per panicle increased. Shading increased the percentage of degenerated spikelets, resulting in the decrease of the number of surviving spikelets per panicle. Higher day/night temperature treatments led to a higher percentage of degenerated spikelets. The treatments affected mainly the spikelets on the secondary branches, while the number of spikelets on the primary branches did not change appreciably, irrespective of the presence of differentiated, degenerated, and surviving spikelets. The influence on the number of surviving spikelets per panicle depended on the number of differentiated spikelets. Shading effect on the percentage of degenerated spikelets also depended on the number of differentiated spikelets per panicle. The decrease of the percentage of degenerated spikelets was associated with the increase of the shoot dry weight (SDW) at heading and the ratio of SDW-differentiated spikelets. The SDW and N absorption at heading affected more significantly the number of surviving spikelets compared to the ratio of surviving spikelets-SDW and surviving spikelets-N, respectively. The above results were similar in Akenohoshi and Yangdao 4. In Akenohoshi, the percentage of degenerated spikelets responded much more conspicuously to the change of SDW or the ratio of SDW -differentiated spikelets than that in Yangdao 4. So did the number of surviving spikelets to SDW and N absorption at heading. Akenohoshi showed a higher ratio of surviving spikelets-N than Yangdao 4. These differences may account for the fact that Akenohoshi showed a larger number of surviving spikelets per panicle than Yangdao 4, even at the same levels of SDW and N absorption.     

A new spore precipitator with polarized dielectric insulators for physical control of tomato powdery mildew

ABSTRACT In an attempt to physically protect greenhouse tomato plants from the powdery mildew fungus Oidium neolycopersici, we developed a new electrostatic spore precipitator in which a copper wire conductor is linked to an electrostatic generator and covered with a transparent acrylic cylinder (insulator). The conductor was negatively charged by the generator, and the electrostatic field created by the conductor was used to dielectrically polarize the insulator cylinder. The dielectrically polarized cylinder also produced an electrostatic force without a spark discharge. This force was directly proportional to the potential applied to the conductor and was used to attract conidia of the pathogen. The efficacy of this spore precipitator in protecting hydroponically cultured tomato plants from powdery mildew was evaluated in the greenhouse. The hydroponic culture troughs were covered with a cubic frame installed with the spore precipitator, and the disease progress on precipitator-guarded and unguarded seedlings was traced after the conidia were disseminated mechanically from inoculum on tomato plants. Seedlings in the guarded troughs remained uninfected during the entire experiment, in spite of rapid spread of the disease to all leaves of the unguarded seedlings.     

Depth perception from image defocus in a jumping spider

The principal eyes of jumping spiders have a unique retina with four tiered photoreceptor layers, on each of which light of different wavelengths is focused by a lens with appreciable chromatic aberration. We found that all photoreceptors in both the deepest and second-deepest layers contain a green-sensitive visual pigment, although green light is only focused on the deepest layer. This mismatch indicates that the second-deepest layer always receives defocused images, which contain depth information of the scene in optical theory. Behavioral experiments revealed that depth perception in the spider was affected by the wavelength of the illuminating light, which affects the amount of defocus in the images resulting from chromatic aberration. Therefore, we propose a depth perception mechanism based on how much the retinal image is defocused.     

Nutrient availability and response of sago palm (Metroxylon sago Rottb.) to controlled release N fertilizer on coastal lowland peat in the tropics

Sago palms (Metroxylon sagu Rottb.) growing on peat soils were found to grow more slowly and to show a lower production than palms growing on mineral soils. This difference was related to the physical and chemical constraints of peat soils, which include low bulk density, high acidity, and low N, P, K, Ca, Zn, and Cu levels. In coastal lowland peat soils, the distance from the sea has been found to be an important determinant of soil elemental composition. We predicted that a sufficient supply of N at the rosette stage would improve sago palm growth and that the availability of N in soil to which controlled release N fertilizer was applied might be higher than that in soil treated with soluble fertilizer. To investigate the changes in the nutrient composition of peat soils at various distances from the sea and the effect on sago palm growth, we studied sago palm areas in Indonesia and Malaysia. To observe the influence of N on the growth performance, we also conducted a fertilizer experiment on coastal lowland peat soil in Indonesia. Distance from the sea had no significant effect on the cation concentration in the soil solution (with the exception of Mg) or on the levels of soil-exchangeable cations. No significant differences were observed between the concentrations of exchangeable cations in surface peat soils and those in mature leaves. However, the concentrations of K, Na, and Ca in mature leaves increased significantly with their concentrations in the soil solution. This finding implies that the concentrations of cations in sago palm leaves depend directly on the concentrations of cations in the soil solution. No significant effect of N fertilizers on plant height and leaf formation was observed. N fertilizers applied twice a year did not affect appreciably the foliar concentration of N determined in December 1998 (5 months after the initial application) and December 1999. In June 2000, we detected a significantly higher concentration of N (p < 0.01) in young leaves of the palms treated with LP-100 or urea than in control leaves. However, no significant difference was detected between the LP-100 and urea treatments in the concentration of N in both mature and young leaves. This finding indicated that the concentration of N in sago palm leaves increased with the level of soil-applied N, regardless of whether N was applied as controlled release fertilizer or in the soluble form. We anticipate that a significant difference in the effects of these N fertilizers may occur during the next rainy season, when there should be a considerable loss of soluble N.