Spontaneous iron accumulation in hepatocytes of a 7-week-old female rat

Spontaneous iron accumulation in hepatocytes was observed in a 7-week-old female Han Wistar GALAS rat. Very fine yellowish brown pigments, which showed a positive reaction with Berlin Blue stain, were apparent in the cytoplasm close to the bile canaliculi, with a diminishing periportal-to-centrilobular gradient. There were also differences in distribution between and within lobes. Transmission electron microscopy revealed cytosolic ferritin and pericanalicular siderosomes in hepatocytes. No degeneration or necrotic changes were observed, and non-hepatocyte cells did not demonstrate any obvious accumulation of iron. There were no abnormalities in the animal other than this finding in the liver.     

Development and evaluation of event-specific qualitative PCR methods for genetically modified Bt10 maize

In 2005 it was reported that the genetically modified (GM) maize strain or "event" called Bt10 had been distributed inadvertently in the United States over the previous 4 years. In order to ensure that grain for food and feed production did not contain trace amounts of Bt10 maize and complied with the applicable regulation, highly sensitive and specific detection of Bt10 maize was required. Accordingly, we developed a novel qualitative PCR system for specific detection of Bt10 maize. Moreover, we amply evaluated the performance characteristics of two PCR systems, our own and the one provided by the developer of Bt10, Syngenta Co. Ltd. It was confirmed that both of the qualitative PCR systems can specifically detect Bt10 maize, and the results of a single-laboratory examination suggested that the limit of detection was approximately less than 0.05% for both methods. To evaluate the reproducibility of the methods, we organized an interlaboratory study with the participation of 6 laboratories and analysis of 240 blind test samples. In this paper, we report, for the first time, the statistical analysis of the qualitative PCR data obtained from the interlaboratory study. The results of this analysis also revealed that there was no significant difference in the sensitivity between the two aforementioned methods and that the limit of detection of both the methods was less than 0.05%. Thus, we conclude that both of the methods are equally suitable for correct identification and sensitive detection of the unapproved GM maize Bt10 event in test samples.     

Distribution of <Emphasis Type="Italic">Typhula ishikariensis</Emphasis> Biotype A Isolates Belonging to a Predominant Mycelial Compatibility Group

The distribution pattern and frequency of isolates of a snow mold fungus, Typhula ishikariensis biotype A belonging to a predominant MCG (mycelial compatibility group, referred to as super MCG), were surveyed throughout its habitat from northern Honshu to eastern Hokkaido. About 38 and 14% of isolates examined belonged to super MCG in eastern and central Hokkaido, respectively ; however, super MCG was never found in southern Hokkaido or northern Honshu. These findings imply that T. ishikariensis biotype A consists of two populations in Japan, i.e., one that is distributed in Honshu and southern Hokkaido and lacks super MCG isolates, and the other that includes super MCG isolates and exists in central and eastern Hokkaido. The difference in distribution pattern of the two populations is discussed in terms of geological history during the Pleistocene (2 million to 10 thousand years ago). The tendency of global warming, which alleviates freezing damage, was considered to be responsible for the outbreak of this fungus in eastern Hokkaido. Received 6 December 1999/ Accepted in revised form 9 December 1999     

Stand parameter estimation of artificial evergreen conifer forests using airborne images: An evaluation of seasonal difference on accuracy and best wavelength

The relationship between the stand parameters (top layer height (H1) and volume/ha (Vha)) and digital number (DN) were evaluated for evergreen conifer stands using three airborne images with 4-m spatial resolution, which were taken in June 1995, September 1993, and October 1994 using the Compact Airborne Spectrographic Imager (CASI). Estimation accuracy of the stand parameters, their seasonal changes, and suitable wavelength were analyzed using correlation coefficients and a regression analysis. The minimum DN of stands, which showed the darkness of a canopy shadow, had a higher correlation with H1 than the average and maximum DN while the average DN had a higher correlation with Vha. The green channels gave the highest correlation coefficients with H1 and Vha, which exceeded — 0.9 for the September and October images. However, the red channels had a consistently high correlation with the stand parameters for the three images. The near infrared channels gave poor correlations with H1 and Vha for the June image. Spectral variations among trees may affect the relationship between DN and the stand parameters in the leaf maturation period in June. Consequently, the late growing season was better at giving consistent results for the stand parameter studies. There was a linear relationship between the measured and the estimated stand parameters for the validation plots especially for the H1 case of September with sufficient accuracy. Nadir viewing images, which had high spatial resolution and a wide dynamic range such as the CASI images, were necessary to estimate the stand parameters accurately. This study was also partly supported by the research project, ‘A Study of Accurate Biomass Estimation using Airborne Imagery,’ of the Science and Technology Agency of Japan. Comments from the editors helped improve the contents of the paper.     

The genetic variability and population structure of the marbled rockfish Sebastiscus marmoratus in western Japan,as inferred by microsatellite DNA markers

Fisheries Science - Identification of the population structure of harvested species is the first step in the management of wild fisheries. Although the marbled rockfish Sebastiscus marmoratus is a...     

Validation of daily increment formation in otoliths of immature and adult Japanese anchovy <Emphasis Type="Italic">Engraulis japonicus</Emphasis>

In order to validate daily increment formation in otoliths of immature and adult Japanese anchovy Engraulis japonicus, three rearing experiments using chemical marking of otoliths were conducted on adult anchovy in summer 2004 and immature anchovy in summer 2005 and in winter 2006. In the two experiments conducted in summer, the number of otolith microincrements between alizarin complexone (ALC) marks showed that microincrements were formed daily. In the summer 2005 experiment, immature anchovy under conditions of reduced daily food rations also showed daily microincrement formation. Average increment width was 0.9 μm in adults and 1.8–3.1 μm in immature anchovy. In contrast, no clear increments were observed between ALC marks on the otoliths from the experiment in winter 2006, and scanning electron microscope (SEM) observations failed to confirm clear increment formation. We consider that low water temperatures (<13–14°C) restricted otolith growth and lowered the contrast between the discontinuous and the incremental zones of the otolith increments. For age estimation of Japanese anchovy, clear increments wider than about 1 μm in the otolith can be regarded as daily increments. However, daily age estimation of immature and adult anchovy that experience low water temperatures in winter may be difficult due to the obscurity of the increments.     

In situ growth and mortality of juvenile Acropora over 2 years following mass spawning in Sekisei Lagoon,Okinawa (24°N)

The growth of Acropora in Sekisei Lagoon was investigated in situ using ceramic coral settlement devices (CSDs) and marine blocks (MBs) with small holes on their surfaces that were deployed prior to a mass spawning event. Acropora that had settled in 10-mm holes on the upper surface of the MBs were found to have grown inwards after 348 days post-mass spawning. After 733 days, the colonies had grown outwards, encrusting the blocks and attaining a maximum diameter of 21.5 mm (3.7 mm). CSDs that had been stacked above each other on frames were separated and observed in situ on 405 and 764 days after mass spawning. After 405 days, the maximum diameter of the encrusting Acropora was 7.6 mm (±2.4 mm), which increased to 19.4 mm (±5.5 mm) after 764 days, with 30% of colonies extending short branches. The length of the branches of Acropora grown on the CSDs fixed to the MBs 3 months after the mass spawning event exceeded the size of the encrusting portion of the colony 629 days after spawning. The mortality of colonies between 1 and 2 years was slight, with the temperatures conducive to coral bleaching that occurred during the study also having only a slight effect.     

Seasonal changes in otolith and somatic growth in age-0 Pacific saury <Emphasis Type="Italic">Cololabis saira</Emphasis>

We evaluated the seasonal changes in otolith and somatic growth of age-0 Pacific saury Cololabis saira in 223 fish collected between June and November 2002. We calculated the age in days of each individual by measuring otolith growth increments under a scanning electron microscope. The age was correlated with body length and otolith radius. We also observed seasonal changes in the rate of increase in body length and otolith radius and in the pattern of otolith growth. Until August, both body length and otolith radius increased with age. Thereafter, the otolith radius continued to increase, whereas the rate of somatic growth decreased. As a result, the ratio of otolith radius to body length increased. After August, the percentage of otoliths with unreadable increments on their edge increased due to the formation of hyaline zones. Otoliths grew both radially and in thickness until July, but gradually stopped growing in thickness after August. Beginning in October, more than 80% of otoliths only grew radially. After August, the otolith not only continued growing but the morphological growth pattern also changed.     

Plasmodium (Bennettinia) juxtanucleare infection in a captive white eared-pheasant (Crossoptilon crossoptilon) at a Japanese zoo

An adult male white eared-pheasant (Crossoptilon crossoptilon) at a Japanese zoo exhibited lethargy and emaciation. Microscopic examination of a blood smear revealed a haemosporidian parasitic infection. Based on the morphological characteristics and molecular analysis of the parasite, it was identified as Plasmodium (Bennettinia) juxtanucleare. This is the first report of P. juxtanucleare infection in bird species belonging to the genus Crossoptilon. Caution against avian malaria infection is required for the conservation of endangered bird species in zoos.     

Expression of podoplanin in various types of feline tumor tissues

Podoplanin is expressed in various human tumors where it promotes tumor progression, epithelial-mesenchymal transition, and distant metastasis. Podoplanin is also expressed in cancer-associated fibroblasts and induces tumor malignancy. The objective of this study was to evaluate podoplanin expression in various types of feline tumor tissues. Immunohistochemical analysis revealed that podoplanin was expressed in cells of 13/15 (87%) squamous cell carcinomas and 5/19 (26%) fibrosarcomas. Moreover, cancer-associated fibroblasts expressed podoplanin in most tumor types, including 18/21 (86%) mammary adenocarcinoma tissues. Our findings demonstrate that various types of feline tumor tissues expressed podoplanin, indicating the importance of the comparative aspects of podoplanin expression, which may be used as a novel research model for podoplanin biology.