Systemic spindle-cell proliferative disease in broiler chickens

The major organs and tissues of 24 broiler chickens (70 or 71 days old) suspected of spindle-cell proliferative disease (SPD) because of showing the tumorous lesions distributed throughout the body at meat inspection were collected for histopathological and immunohistochemical examination. Macroscopically, liver, spleen and cecal tonsil showed severe enlargement and white nodules or plaques were observed in the liver, spleen, kidney, intestine and bone marrow of the femur. All chickens were diagnosed with SPD based on the histopathological examination. The lesions of SPD were observed in the liver, spleen, kidney, heart, lung, pancreas, proventriculus, gizzard, duodenum, jejunum, ileum, rectum, cecal tonsil, bursa of Fabricius, bone marrow of the femur and skin. Hemangioma was observed in the lung of 1 bird. Eight 1-day-old specific pathogen-free chicks were inoculated intraperitoneally with 0.25 ml of a 20% homogenate of the affected spleens of three naturally occurring cases. One inoculated bird, necropsied at 10 weeks of age, macroscopically had a white nodule in the kidney and histopathologically had spindle-cell proliferative lesions, a pattern similar to that seen in the naturally occurring cases, in the liver, spleen, kidney, heart, lung, pancreas, proventriculus, duodenum, cecal tonsil and bone marrow of the femur, and was diagnosed with SPD. Immunohistochemically, significant positive reactions with a rabbit antiserum against avian leukosis virus antigens were detected in all spindle cells in the proliferative lesions of all examined SPD cases and in tumor cells of the hemangioma of a field case.     

Development of a numerical model for evaluating the effect of litter layer on evaporation

A numerical model (LITEM) to evaluate the effect of the litter layer on evaporation was developed and used to estimate evaporation, soil temperature and soil water content. This model includes a sub-model to estimate the resistance of the litter layer to evaporation with its thickness and volumetric water content. The resistance of the litter layer to evaporation increases as volumetric water content of the litter layer decreases and as its thickness increases. Evaporation data in a deciduous broad-leaved forest measured using microlysimeter was simulated by the LITEM. The simulation showed good agreement with the measurement, and sound performance of the sub-model in simulation was also certified. According to the measurement for 2 days, evaporation from soil of 1.5 cm and 2 cm litter layers to that from bare soil was reduced to 47% and 61%, respectively. Loss of soil water content in three soils (bare soil, 1.5 cm litter layer and 2 cm litter layer) by evaporation was simulated by the LITEM, and the LITEM reasonably expressed the trend of volumetric soil water content. The simulated soil temperatures also showed good agreement with the field data.     

Derivation of a yearly transition probability matrix for land-use dynamics and its applications

Transition matrices have often been used in landscape ecology and GIS studies of land-use to quantitatively estimate the rate of change. When transition matrices for different observation periods are compared, the observation intervals often differ because satellite images or photographs of the research site taken at constant time intervals may not be available. If the observation intervals differ, the transition probabilities cannot be compared without calculating a transition matrix with the normalized observation interval. For such calculation, several previous studies have utilized a linear algebra formula of the power root of matrices. However, three difficulties may arise when applying this formula to a practical dataset from photographs of a research site. We examined the first difficulty, namely that plural solutions could exist for a yearly transition matrix, which implies that there could be multiple scenarios for the same transition in land-use change. Using data for the Abukuma Mountains in Japan and the Selva el Ocote Biosphere Reserve in Mexico, we then looked at the second difficulty, in which we may obtain no positive Markovian matrix and only a matrix partially consisting of negative numbers. We propose a way to calibrate a matrix with some negative transition elements and to estimate the prediction error. Finally, we discuss the third difficulty that arises when a new land-use category appears at the end of the observation period and how to solve it. We developed a computer program to calculate and calibrate the yearly matrices and to estimate the prediction error.     

Influence of Sulfur and Nitrogen Content of Rice Grains on Flavor in Stored Sake

The influence of nitrogen and sulfur compounds in rice grains on changes in flavor in stored sake was investigated using Japanese rice cultivars for sake making. Nitrogen content exhibited a significant positive correlation with sulfur content. Based on the molar ratio of nitrogen to sulfur in the rice grain, the sulfur compounds appeared to be derived from protein‐associated sulfur‐containing amino acids, as reported previously. The higher the protein content of the rice, the greater the amount of nitrogen and sulfur compounds found in both the digest of steamed rice grains and in the sake. Physicochemical changes were investigated in the stored sake to confirm the influence of total sulfur content. Polysulfides in the stored sake appeared to be higher when made from rice grains of high total sulfur content. Staling of stored sake was affected by levels of protein‐associated sulfur‐containing amino acids in the rice.     

Impact of wind direction on diurnal and seasonal changes in wind profiles

We explored the relationship between directional variation (changes in direction from a reference point) in vegetation and wind profiles, and propose an empirical wind profile model that may reproduce the wind profile within the canopy (such as secondary wind maximum) and reduce calculation loads. Based on the results of our observations in secondary broad-leaved forest, we clarified the variation in secondary wind maximum and aerodynamic parameters in wind direction, and assessed the influence of forest structural heterogeneity on the wind profile. Wind blew from specific directions depending on the time of day and season, and secondary wind maxima were observed in particular wind directions. Outlier estimations of aerodynamic parameters were determined for wind directions of 45°, 120–210°, and 300°, and these did not show a logarithmic distribution. Our proposed model reproduced the wind profile within and above the canopy, closely resembling K-theory and closure models, and reduced the required number of calculations and observations. The influence of forest structural heterogeneity was greatest in the upper part of the canopy (9.14 m), and reproducibility of the wind profile was improved by 0.05 m/s (3.4% on average) by changing the forest structural parameters of the model according to the wind direction. It was clear that forest structural heterogeneity did not cause critical errors in estimation of the wind profile, even at our study site, which had complex forest structure.     

Application of a compact magnetic resonance imaging system for toxicologic pathology: evaluation of lithium-pilocarpine-induced rat brain lesions

Magnetic resonance imaging (MRI) is a useful noninvasive tool used to detect lesions in clinical and veterinary medicine. The present study evaluated the suitability of a new easy-to-use compact MRI platform (M2 permanent magnet system, Aspect Imaging, Shoham, Israel) for assisting with preclinical toxicologic pathology examination of lesions in the rat brain. In order to induce brain lesions, male Sprague-Dawley rats were treated once with lithium chloride (127 mg/kg, intraperitoneal [i.p.]) followed by pilocarpine (30 mg/kg, i.p.). One week after dosing, the perfused, fixed brains were collected, analyzed by the MRI system and examined histopathologically. MRI of the brain of treated rats revealed areas of high T1 and middle to low T2 signals, when compared with the controls, in the piriform cortex, lateral thalamic nucleus, posterior paraventricular thalamic nucleus and posterior hypothalamic nucleus of the cerebrum. The altered MRI signal areas were consistent with well-circumscribed foci of neuronal cell degeneration/necrosis accompanied by glial cell proliferation. The present data demonstrated that quick analysis of fixed organs by the MRI system can detect the presence and location of toxicologic lesions and provide useful temporal information for selection of appropriate sections for histopathologic examination before routine slide preparation, especially in complex and functionally heterogeneous organs such as the brain.     

Trophodynamic structure of a swampy Bog at the climax stage of limnological succession IV. Vertical migration and demersal behaviour of large zooplankton

The diel vertical migration and the demersal behaviour of crustacean zooplankton were studied throughout the year at Matsumi-ike Bog. Population densities of the predominant species of crustacean zooplankton within the water column were much smaller during the morning than during the night. Most of their migration was directed to the bottom layer during the morning unlike at night. The population density of zooplankton inside the ooze sediment increased significantly in the morning. In a shallow area where the diel vertical migration of zooplankton is insufficient to escape from the predation of visually oriented planktivorous fish, demersal behaviour appears to be an important adaptation for the survival of zooplankton.     

A PCR-based assay for differentiating A- and A*-type strains of Xanthomonas citri subsp. citri, the causal agent of Asiatic citrus canker

By applying A- and A*-type strains of Xanthomonas citri subsp. citri (Xcc) in a repetitive sequence-based polymerase chain reaction (rep-PCR), two DNA amplicons, one unique to each strain, were evaluated as a probe against the DNA of Xcc strains. Two pairs of primers derived from these amplicons were tested in a PCR analysis. The results confirmed that primers Ms⁺/Ms^? are useful for differentiating A-type from A*-type strains of Xcc. Also, a multiplex PCR with both set of primers can be used to distinguish three groups in Xcc populations: A-type strains and two subgroups of A* strains including Iranian and Thai A* strains.     

Prevalence of Salmonella spp. in pet reptiles in Japan

From November 2000 to July 2002, 112 fecal samples from pet reptiles, including 18 turtles, 71 lizards and 23 snakes, sold at a pet shop were examined for the prevalence of Salmonella spp. in Japan. Salmonella spp. were isolated from 83 (74.1%) of 112 samples, and a total of 112 Salmonella isolates were identified as subspecies I to IV. The majority of isolates (62.5%) belonged to subspecies I and 54 isolates could be identified as any of 28 serovars. The predominant serovars were found to be S. Bardo, S. Newport and S. Panama, which cause human salmonellosis. These results indicate that pet reptiles may be a potential infectious source of human salmonellosis in Japan.