Temporal and topographic profiles of tissue hypoxia following transient focal cerebral ischemia in rats

Intravascular accumulation of blood cells after brain ischemia-reperfusion can cause obstruction of cerebral blood flow and tissue hypoxia/ischemia as a consequence. In the present study, we examined temporal and topographic changes of tissue hypoxia/ischemia after occlusion of the middle cerebral artery (MCA) for 60 min in rats with immunohistochemical staining for hypoxia (2-nitroimidazole hypoxia marker: hypoxyprobe-1 adducts). Our results showed that tissue hypoxia expressed as positive staining for hypoxyprobe-1 adducts preceded neuronal degeneration. Platelets and granulocytes were detected close to the hypoxyprobe-1 adducts positive area. These results suggested that the hypoxic environment could persist even after reperfusion of MCA, because of vascular obstruction with accumulation of platelets and granulocytes.     

Object-based forest biomass estimation using Landsat ETM+ in Kampong Thom Province, Cambodia

Information about forest biomass distribution is important for sustainable forest management and monitoring fuelwood supply. The objective of this study is to develop an accurate forest biomass map for Kampong Thom Province, Cambodia. We used a new technique (object-based approach) and a conventional technique (pixel-based approach) for the estimation of forest biomass using Landsat Enhanced Thematic Mapper Plus (ETM+). The object-based approach created segments of images, and calculated statistical and textural attributes. Our results showed that estimation accuracy of the object-based approach, with the use of band 1 and an exponential fit, was the best (R ² = 0.76), and this accuracy was comparable to that of the pixel-based approach (R ² = 0.67). Although several textural variables were related to forest biomass, they did not contribute significantly to improvement of estimation accuracy. However, the object-based method can be used for image segmentation so that the image objects are spectrally more homogeneous within individual regions than with their neighbors. Hence, they can be regarded as management units for policy-related spatial decisions. Therefore, it is possible to select either of the two methods depending upon what the situation demands.     

Coordination of crown structure, leaf plasticity and carbon gain within the crowns of three winter-deciduous mature trees

We examined the vertical profiles of leaf characteristics within the crowns of two late-successional (Fagus crenata Blume and Fagus japonica Maxim.) and one early-successional tree species (Betula grossa Sieb. et Zucc.) in a Japanese forest. We also assessed the contributions of the leaves in each crown layer to whole-crown instantaneous carbon gain at midday. Carbon gain was estimated from the relationship between electron transport and photosynthetic rates. We hypothesized that more irradiance can penetrate into the middle of the crown if the upper crown layers have steep leaf inclination angles. We found that such a crown has a high whole-crown carbon gain, even if leaf traits do not change greatly with decreasing crown height. Leaf area indices (LAIs) of the two Fagus trees (5.26-5.52) were higher than the LAI of the B. grossa tree (4.50) and the leaves of the F. crenata tree were more concentrated in the top crown layers than were leaves of the other trees. Whole-crown carbon gain per unit ground area (micromol m(-2) ground s(-1)) at midday on fine days in summer was 16.3 for F. crenata, 11.0 for F. japonica, and 20.4 for B. grossa. In all study trees, leaf dry mass (LMA) and leaf nitrogen content (N) per unit area decreased with decreasing height in the crown, but leaf N per unit mass increased. Variations (plasticity) between the uppermost and lowermost crown layers in LMA, leaf N, the ratio of chlorophyll to N and the ratio of chlorophyll a to b were smaller for F. japonica and B. grossa than for F. crenata. The light extinction coefficients in the crowns were lower for the F. japonica and B. grossa trees than for the F. crenata tree. The leaf carbon isotope ratio (delta(13)C) was higher for F. japonica and B. grossa than for F. crenata, especially in the mid-crown. These results suggest that, in crowns with low leaf plasticity but steep leaf inclination angles, such as those of F. japonica and B. grossa trees, irradiance can penetrate into the middle of the crowns, thereby enhancing whole-crown carbon gain.     

First report of whisker mold,a postharvest disease on citrus caused by <Emphasis Type="Italic">Penicillium ulaiense</Emphasis> (in Japan)

In March 2006, stored fruits of the medium-to-late-ripening citrus variety Shiranuhi ([Citrus unshiu × C. sinensis] × C. reticulata) were found to have a disease similar to blue mold. The fungus causing this disease differed distinctly from the well-known, blue mold agent, Penicillium italicum, because it formed whisker-like coremia measuring 1–8 mm. On the basis of the morphological characteristics and the phylogenetic analysis based on the nucleotide sequence of the β-tubulin gene, the fungus was identified as P. ulaiense. This is the first report of citrus whisker mold caused by P. ulaiense in Japan.     

Sooty spot caused by Cladosporium cladosporioides in postharvest Satsuma mandarin grown in heated greenhouses

In June 2006, a large number of small black spots containing a branching network of black hyphae developed on shipped Satsuma mandarin fruits grown in greenhouses, which markedly decreased their commercial value. The fungus that was frequently isolated from the damaged fruits was identified as Cladosporium cladosporioides. Inoculation of fruits with the fungus caused the same symptoms, and the fungus was reisolated from the diseased fruits. The disease caused by this fungus has not been previously documented in citrus fruits; we name this new disease “sooty spot” on the basis of its symptoms.     

Phytotoxin produced by Streptomyces sp. causing potato russet scab in Japan

A phytotoxin isolated from the Stretomyces sp. causing potato russet scab in Japan (Kamenoko-byo in Japanese) was identified as a 16-membered macrolide, FD-891. It induced necrosis in potato tuber slices above 50 µg/disk, which is about 1/100 the activity of thaxtomin A. The phytotoxin was detected in potatoes infected by the pathogen and was produced by other pathogenic strains with different geographic origins.     

Plasma concentration of vitamin C in dogs with a portosystemic shunt

Most mammals, including dogs, synthesize vitamin C in the liver. We measured the plasma concentration of vitamin C to assess the body vitamin C status in 15 dogs with a portosystemic shunt (PSS). The plasma biochemical parameters indicated liver abnormalities in all the dogs. In contrast, the plasma concentration of vitamin C ranged from 2.21 to 9.03 mg/L in the 15 dogs and was below the reference range (3.2 to 8.9 mg/L) in only 2 dogs. These findings suggest that vitamin C status is not impaired in dogs with PSS.     

Ecological characterization of three different phylogenetic groups belonging to the cellulolytic bacterial species Fibrobacter succinogenes in the rumen

To study the group‐dependent ecology of Fibrobacter succinogenes in the rumen, real‐time polymerase chain reaction assays for two phylogenetic groups (groups 2 and 3) of F. succinogenes were newly established and applied to rumen samples. Both the assays targeting the bacterial 16S rDNA were sensitive and accurate, showing wide quantifiable ranges (10⁴?10⁹ and 10²?10⁹ copies of 16S rDNA) and high recoveries of known amounts of added DNA (96.9 and 98.0%). The quantity of group 1 was confirmed to be numerable by subtracting assay values of groups 2 and 3 from that of F. succinogenes species (groups 1–3). By using the developed assays and the above subtractive calculation, the quantities of all three groups were evaluated in solid and liquid fractions of the rumen content and also on hay stems. In the solid fraction, groups 1 and 2 were abundantly present, compared with group 3 (P < 0.05). On untreated hay stems, group 1 was dominant throughout 48 h. In addition, group 1 showed growth even on the cellulase‐treated hay stems, unlike the other two groups. These results suggest that F. succinogenes group 1 greatly contributes to rumen fiber digestion, even for less degradable materials.     

Root response to aerobic conditions in rice,estimated by Comair root length scanner and scanner-based image analysis

Precise evaluation of root system architecture is important for understanding how rice plants are adapted to non-puddled and non-flooded conditions in aerobic culture. The objective of this study was to compare estimates of root length by the Comair root length scanner and a flat bed scanner and image analysis software in rice grown in aerobic, near-saturated and flooded fields. Fine roots (diameter < 0.2 mm) accounted for >80% of root length in all hydrological conditions. The Comair root length scanner detected fewer fine roots than the software; root length estimated by the Comair scanner was between that of roots wider than 0.1 mm and roots wider than 0.2 mm estimated by image analysis software. Importantly, total root length under aerobic and near-saturated conditions was 10–30% of that under flooding by image analysis software, but not by the Comair scanner. Digital image analysis detected genotypic differences in fine root development in the subsurface layer in aerobic culture that the Comair root length scanner would have missed. Although root length measurement by image analysis software is still under development, this new tool will facilitate the phenotyping of root system architecture and shed light on the roles of fine roots in water-saving rice cultivation.     

Comparative observations of the growth changes of the histochemical properties and collagen architecture of the iliotibialis lateralis muscle from Silky, layer and meat type cockerels

Growth‐related changes in the histochemical property and collagen architecture of the iliotibialis lateralis muscle were compared among Silky, layer and meat cockerels. Histochemical and immunohistochemical methods were employed to observe the collagen architecture. The total intramuscular collagen was also determined. The muscle consisted of type IIA, IIB and IIC myofibers, of which type IIB occurred at the highest frequency. The diameter of type IIB myofibers in each week was largest in the layer, followed by the meat, and was smallest in the Silky. The total amount of collagen reached 3.38 mg/g in the meat bird, 3.03 mg/g in the layer and 2.71 mg/g in the Silky by 30 weeks of age, respectively. In the perimysium, the collagen bundles increased in size and density of fibrils with growth. At 30 weeks of age the layer had compact collagen platelets while the Silky had loose collagen bundles. In the meat bird, the collagen bundles were moderately compact. The endomysial collagen network had a large mesh size at 1 week and thereafter accumulated many collagen fibrils to form a felt‐like fabric of fibrils at 30 weeks of age. From these results it appears that growth‐related changes in the iliotibialis lateralis muscle are not necessarily causally affected by the different growth rates of chicken breeds.