Pathology of canine oral malignant melanoma with cartilage and/or osteoid formation

Of 197 cases of canine oral malignant melanoma, 29 cases with myxoid, cartilage, and osteoid formation were studied pathologically and immunohistochemically. Tumor tissues were classified into spindle cell type (13 cases), epithelioid cell type (1 case), and mixed type (15 cases). Myxoid matrixes (29 tumors) were formed mainly in the tissues of spindle cell type and were positive for Alcian blue (pH 2.5). Cartilaginous matrixes (12 tumors) were formed in the myxoid tumor tissues. The morphology of atrophied neoplastic cells, which were embedded in the cartilage cavities, significantly differed from that of spindle cells proliferating in surroundings. There were reticular areas in the process of transitioning from myxoid to cartilaginous matrixes. Osteoid matrixes were not continuous with myxoid or cartilaginous matrixes, and arose as eosinophilic trabeculae in the dense collagenous connective tissues. A calcified bone trabecula was present among the osteoid trabeculae in a case. Melanin-producing melanocytes were proliferating in the collagenous matrixes, while amelanotic cells were in the osteoid matrixes. Immunohistochemistry demonstrated proliferating neoplastic cells as melanocytes. All cells in/out of these three matrixes were positive for Melan-A, S-100 protein, NSE, and vimentin. From these results, it is suggested that cartilage and osteoid matrixes are produced by dedifferentiated melanocytes.     

Effect of shelter acclimation on the post-release movement and putative predation mortality of hatchery-reared black-spot tuskfish <Emphasis Type="Italic">Choerodon schoenleinii</Emphasis>, determined by acoustic telemetry

In this study, the effect of shelter acclimation on the post-release movement and putative predation mortality of hatchery-reared black-spot tuskfish Choerodon schoenleinii was examined using acoustic telemetry. We acclimated four 1-year-old fish to shelters in cages before release and compared their movements with six nonacclimated fish. Since it was not possible to compare the behavioral pattern between the former and the latter fish due to the short periods the latter fish were available to be monitored, we also compared their movements with those of large nonacclimated fish that were less likely to be preyed upon. Sixty-seven percent of the nonacclimated fish showed atypical movements before the signals ceased to be detected, a pattern that suggested a predation event had occurred, whereas none of the acclimated and large nonacclimated fish showed the atypical movements. In addition, the probability of detection cessation was about 13 times lower in the acclimated than nonacclimated fish. The signal detection patterns suggest that the acclimated fish utilized night-time shelters from the first night after release, while the large nonacclimated fish started to utilize shelters several days after release. Therefore, it is likely that the shelter acclimation enhanced the shelter utilization by tuskfish, possibly decreasing post-release predation mortality.     

Social rank modulates brain arginine vasotocin immunoreactivity in false clown anemonefish (<Emphasis Type="Italic">Amphiprion ocellaris</Emphasis>)

The brain nanopeptide arginine vasotocin (AVT) and its mammalian homolog arginine vasopressin are involved in the regulation of social and reproductive behavior. We investigated the relationship between social rank formation and the brain AVT system in the false clown anemonefish (Amphiprion ocellaris), which forms a social rank that leads to sex differentiation in higher-ranked individuals. Tanks of three sexually immature fish were kept for 90 days and each fish’s behavior was observed once a month. The social rank of each individual was distinguishable by behavior, but gonadosomatic index (GSI) did not differ significantly. The number of AVT neurons in the magnocellular layer in the preoptic area (POA) increased in subordinate individuals and declined with increasing hierarchical dominance. These results suggest that social rank formation modulates AVT production in the brain of the clown anemonefish and may influence their later sex differentiation.     

Analysis of Proton Generation and Consumption of Forest Surface Soils in Hokkaido, Northern Japan

We determined proton budgets of surface soils in a deciduous forest (Df) and a coniferous forest (Cf) of Volcanogenous Regosols in Tomakomai, Hokkaido of northern Japan. The total H⁺ source was 12.9 and 11.6 kmol_c ha^?1 y^?1 at Df and Cf respectively, and the external H⁺ was 1% at Df and 2% at Cf. The primary H⁺ sources were vegetation uptake of base cations and nitrification, while the major H⁺ sinks were release of base cations and NO₃ ⁺ uptake by vegetation. Leaching incubation experiments using A horizon soils including Df and Cf with NH₄ ⁺ solutions (5.3, 15.9 mg N L^?1) showed that H⁺ from nitrification was generally higher in the Df soil than Cf soil, and nitrification of Tomakomai Df soil was the highest in both treatments. Results of multiple regression analyses suggested that pH_kCl and exchangeable Ca²⁺ contributed to the H⁺ generation via nitrification. Leaching experiments with dilute HCl (pH 3.3) revealed that cation release (mainly Ca²⁺) occurred, and the proportion of release by decrease of exchangeable cations was higher than that by mineral weathering. Mineral weathering in the Tomakomai soil was higher than the other soils.     

<Emphasis Type="Italic">Ophiostoma</Emphasis> species associated with bark beetles infesting three <Emphasis Type="Italic">Abies</Emphasis> species in Nikko,Japan

Ophiostoma species were isolated from bark beetles and Abies mariesii, A. veitchii and A. homolepis attacked by the beetles in Nikko, Tochigi, central Honshu, Japan. One to two Ophiostoma species were frequently isolated from each species of bark beetle. Ophiostoma subalpinum was the most common associate of Cryphalus montanus. Ophiostoma sp. B as well as O. subalpinum was a common fungus associated with Polygraphus proximus. Ophiostoma europhioides was isolated from Dryocoetes hectographus and D. autographus as one of the common associates. Ophiostoma sp. J and Ophiostoma sp. S were frequently isolated from D. autographus and D. striatus, respectively. These fungi seem to have specific relationships with particular bark beetles. Ophiostoma sp. B, Ophiostoma sp. J and Ophiostoma sp. S have unique morphological characteristics and appear to be new species. Five trees of A. veitchii, approximately 43 years old, were inoculated with five Ophiostoma species to assess the relative virulence of the fungi. Ophiostoma subalpinum, Ophiostoma sp. B, and O. europhioides had relatively higher virulence than the other species studied.     

亚热带常绿阔叶林结构、树种多样性和土壤特性的研究(英文)

采用样地调查法,对日本冲绳岛北部的亚热带常绿阔叶林的林分结构,树种组成以及土壤特性等进行了调查分析。结果表明,该亚热带林具有林冠低矮、小径木多等特点。林分的平均林冠高度仅10m,平均立木密度达5400株·hm2(≥3.0cmDBH),其中胸径小于10cm的立木占64%。林分胸高断面积为54.4m2·hm-2。30个调查样地共出现树种数(≥3.0cmDBH)达80种,分属31个科。根据树种的重要值,Castanopsis sieboldii和Schima wallichii分别为优势树种和亚优势树种。树种多样性指数(H’)平均达3.63,均衡度指数(J’)为0.71,丰富度指数(S’)为4.72。这些多样性指数都随着优势树种重要值的增加而显著降低。土壤养分测定结果表明,该森林的土壤肥力低,异质性大,并可能存在Al毒害。由相关分析知,林分密度和优势树高均与土壤pH值呈显著正相关关系;多样性指数则与土壤交换性K ,Ca2 以及Ca2 /Al3 比呈显著的正相关,而与土壤有机碳,全氮和磷呈显著的负相关。这些结果说明土壤性质是影响冲绳亚热带常绿阔叶林林分结构和树种组成多样性的重要因素。图3表4参38。     

玉米自交系对低钾胁迫耐性的差异

采用耐低钾的玉米自交系T和一般的自交系C,以4水平钾浓度的水培方法进行对照研究。结果表明,在高钾情况下,两自交系干重几乎相同,随着钾浓度的下降,自交系T的干重明显大于自交系C:;随钾浓度的下降,自交系C缺钾症状加重,而自交系T除一K处理外均无缺钾症状;缺乏钾素。自交系C的主根伸长增加及冠/根比下降程度比自交系T明     

Effect of water temperature on gonadal development and emaciation of Japanese common squid <Emphasis Type="Italic">Todarodes pacificus</Emphasis> (Ommastrephidae)

ABSTRACT:   In this study, the site of spawning ground and the relationship between oceanographic conditions and gonadal development and emaciation of the Japanese common squid Todarodes pacificus were examined based on data from research cruises. The research cruises were conducted in the south-western part of the Sea of Japan and the East China Sea in the winter of 1999. Sea surface temperature (SST) ranged 12.7–23.2°C in the survey area. Mature females concentrated on the continental shelf of the East China Sea, suggesting a major spawning ground was formed in this area. Gonadal development of the collected squid was examined using ovary somatic index (OSI) and oviduct somatic index (ODSI) in females, and emaciation was examined using mantle muscle somatic index (MI) and hepatosomatic index (HSI). Mean OSI and ODSI increased with SST at the stations where SST was greater than 15°C, particularly where SST ranged between 15 and 18°C. In contrast, mean MI and HSI decreased with increase in SST at the stations where SST was above 15°C. These results indicate that female gonads develop rapidly at SST above 15°C, and at the same time adult squids tend to be emaciated at this temperature condition.     

Assessing bottom structure influence on fish abundance in a marine hill by using conjointly acoustic survey and geographic information system

ABSTRACT:   Acoustic survey and a geographic information system (GIS) were used conjointly to estimate the significance of bottom substrate to explain fish abundance distribution in the complex topography context of a marine hill. The survey was conducted in the Hachirigase hill, off south-western Honshu Island in the Sea of Japan. Analysis of acoustic data focused on a 10-m thick layer beginning at the bottom, assuming that bottom influence does not exceed this distance. Area backscattering strength ( S _a ) values were rescaled in order to reflect real differences before being analyzed. Results show that the influence of the different parameters taken into account (bottom depth, bottom substrate and water temperature) varies widely from one place to another. Bottom substrate is above all important in the zone located to the west of the peak. The kriging and stratification methods were applied to the S _a distribution for estimating the total S _a in the hill. Differences between results are discussed. Conjoint use of acoustic survey and GIS is an effective method for analyzing and estimating fish abundance distribution in a marine hill.     

Spatiotemporal change in growth of two populations of Asian chum salmon in relation to intraspecific interaction

Spatiotemporal changes in growth patterns of chum salmon Oncorhynchus keta that returned to the Ishikari (Japan) and Namdae (Korea) rivers in 1984–1998 were investigated using scale analysis. Juvenile chum salmon from both populations left coastal marine areas after spring at a size of over 8 cm fork length (FL). In summer, juvenile salmon from the Namdae River entered the Okhotsk Sea at a larger FL than did Ishikari River juveniles. There were no significant differences in annual growth between populations of 1-, 2-, and 4-year-old fish. For 3-year-old fish, however, Namdae River salmon had significantly higher synchronous and sympatric growth than did Ishikari River salmon. Mean FL of adults was also larger in Namdae River salmon than in Ishikari River salmon. Analysis of covariance (ANCOVA) results showed (1) negative linear relations between FL and catch, (2) homogeneous slopes of those relations at regional and species levels, and (3) nonhomogeneous slopes at the population level, indicating that density-dependent effects on growth were most significant at this level. We concluded that growth of chum salmon was concurrently influenced by stronger effects of intrapopulation competition and weaker effects of inter- and intraspecific interactions in the Bering Sea.