Factors determining the distribution of a keystone understory taxon, dwarf bamboo of the section Crassinodi, on a national scale: application to impact assessment of climate change in Japan

The objective of this study was to identify climatic factors determining the distribution of a keystone understory taxon, section Crassinodi of the genus Sasa, and assess the impacts of climate change on the taxon. Relationships between the distribution of sect. Crassinodi and five climatic variables were explored using classification tree analysis. Potential habitats under current climate and future climate in 2081–2100 were predicted. Potential habitats were further divided into suitable and marginal habitats. The predictive accuracy of the model was assessed using receiver operating characteristic analysis and by comparing model predictions with an independent dataset. The model was reasonably accurate. It showed that the warmth index (WI) and snow cover were the most important climatic variables for Crassinodi distribution. Potential habitats were limited to cooler regions with WI <102.7°C month. Suitable habitats were limited to even cooler regions with WI <84.8°C month. The model also showed that areas with deeper snow than previously reported would provide suitable habitats for Crassinodi under some climatic conditions. In 2081–2100, 37.4% of current potential habitats are predicted to become non-habitats because of increases in WI. Most currently suitable habitats are predicted to vanish from western Japan by 2081–2100. Meanwhile, Hokkaido and high-elevation areas of eastern Honshu will sustain suitable habitats. Sect. Crassinodi, which is adapted to less snowy climates, is predicted to be more affected by climate change than sect. Sasa and Macrochlamys, which are adapted to snowy climates.     

Detection of a bovine group C rotavirus from adult cows with diarrhea and reduced milk production

Only two strains (Shintoku and porcine-like WD534tc) of group C rotavirus (GCR) from cattle have been reported to date. A GCR designated the Yamagata strain was the only pathogen detected in an outbreak of adult cow diarrhea accompanied by a decrease in milk production. The nucleotide sequences of the VP6 and VP7 genes from strain Yamagata were determined. Comparative sequence analysis showed that the sequence identities between strains Yamagata and Shintoku were markedly high in both VP6 gene (98.1%) and VP7 gene (93.5%), and that these strains belonged to the same clusters which were distinguished from GCRs from different host species in phylogenetic trees of these genes. These results suggested strongly that cattle species is one of the natural hosts of GCR infection, and that GCRs are a cause of adult cow diarrhea.     

A case of spontaneous Zymbal’s gland carcinoma with lung metastasis in an aged Fischer 344 rat

Zymbal’s gland neoplasms are induced in rats through the administration of various carcinogens, but spontaneous neoplasia is rare. This report describes a spontaneous Zymbal’s gland carcinoma with lung metastasis found in an aged male Fischer 344 rat. Macroscopically, the dome-like tumor nodule, approximately 30 mm in diameter with ulceration, was located near the ear canal of the rat. No healthy tissue or structure of Zymbal’s gland was identified on the corresponding side, while the normal salivary glands and a lacrimal gland were observed. Histologically, a large part of the tumor mass was occupied by poorly differentiated neoplastic cells, the shapes of which were oval to polygonal or fusiform. Additionally, clusters of sebaceous-like foamy cells and squamous metaplasia with prominent keratinization were observed. Tumor cells were found to metastasize to the lung; these cells displayed histological similarities, including a sebaceous gland-like pattern, to those in the primary site. The tumor cells were immunohistochemically positive for cytokeratin AE1/AE3 or vimentin but negative for CD68, S100, α-smooth muscle actin, von Willebrand factor, and desmin. Our results indicate that the tumor was a poorly differentiated Zymbal’s gland carcinoma with lung metastasis.     

What controls the distribution of the Japanese endemic hemlock, Tsuga diversifolia? Footprint of climate in the glacial period on current habitat occupancy

Plant distributions are thought to be controlled by climate at large scales, and by non-climatic factors including soil conditions, topography and biotic interactions at smaller scales. However, not all plant distributions are explained by the current environment. Lags between current plant distributions and suitable environment for them are suggested to exist, which is often called empty habitat. To identify the existence and cause of lags between current climate and the distribution of Tsuga diversifolia, climatic conditions for the species distribution were clarified and potential habitats under current and the last glacial maximum (LGM; 21 ka) climates have been projected. The relationships between T. diversifolia distribution and climatic variables were explored using a classification tree model and a generalized additive model based on high-resolution (ca. 1 km) climatic data and a nationwide distribution database. The models were highly accurate. We revealed that T. diversifolia requires high summer precipitation even in humid Japanese environments. Areas with cool and wet summers were classified as potential habitat. Empty habitat for the focal species was identified in Hokkaido. Meanwhile, no potential habitat was projected in Hokkaido under the LGM. Additional experiments that varied temperature and summer precipitation during the LGM showed that the potential habitat was projected in Hokkaido irrespective of temperature decrease if summer precipitation increased nearly equal to the current climate. These results suggest that T. diversifolia vanished from Hokkaido, where fossil evidence indicated its occurrence until the late Neogene, during the glacial periods of the Pleistocene because of increased summer dryness.     

Atomic force microscopy of thermally treated myosin filaments

Heat-induced morphological change in myosin filaments was observed using atomic force microscope. The thickness of fixed native myosin filament was estimated to be 95 +/- 5 nm. When myosin filaments in 0.1 M NaCl at pH 6.0 were heated at 40, 55, and 70 degrees C for 10 min, the particulate structure appeared spirally on the surface of the filament at 40 degrees C, and the thickness of the filament was 75 +/- 10 nm. When myosin filaments were treated at 55 degrees C, several filaments were formed associated with side-by-side interaction through projected myosin heads to form a strand. The surface of the strand looked knobby. The thickness of thermally denatured filaments at 55 degrees C was 48 +/- 5 nm, and that of strands was about 80-110 nm, indicating the involvement of several filaments in a strand. The strands became to be rope-like at 70 degrees C, and the individual filaments in a strand were not distinguishable.     

Climatic controls of a keystone understory species, <Emphasis Type="Italic">Sasamorpha borealis</Emphasis>, and an impact assessment of climate change in Japan

Introduction   

The aims of this study were to identify the climatic conditions controlling the distribution of Sasamorpha borealis and to assess the impact of climate change on the species in Japan.     

Determination of Mugineic Acid, 2′-Deoxymugineic Acid, 3-Hydroxymugineic Acid,and Their Iron Complexes by Ion-Pair HPLC and Colorimetric Procedures

Extract

Under iron (Fe)-deficient conditions like in calcareous and/or high pH soils, mugineic acid family phytosiderophores (MAs: mugineic acid (MA), 2′-deoxymugineic acid (DMA), 3-hydroxymugineic acid (HMA) etc.) are secreted from graminaceous plants and solubilize the slightly soluble Fe in soil as MAs-Fe complexes (Takagi 1976, 1993). Due to their high availability to higher plants (Roemheld and Marschner 1986), the behavior of MAs and their Fe complexes in the soil environment is of interest in connection with the iron nutrition of these plants.     

Mineralogical properties of andisols of the Kitakami mountain range,Northeastern Japan

We studied the mineralogical properties of Andisols of the Kitakami mountain range. Soils of the northern and central parts of the mountain range contained higher levels of acid oxalate extractable silicon (Si_o), aluminum (A1_o), and iron (Fe_o) but smaller amounts of sodium pyrophosphate-extractable aluminum (Al_p), iron (Fe_p), and carbon (C_p) than those of the southern part. Consequently, the soils of the northern and central parts of the mountain range contained large amounts of allophane and ferrihydrite whereas in the soils of the southern part A1 (Fe)-humus complexes and 2:1 and 2:1:1 clays predominated. The amount of sand (20-2,000 μm) in the soils tended to decrease sharply from the north to the south of the mountain range. The soils of the northern and central parts of the mountain range contained larger amounts of heavy minerals in their fine sand fraction (20-200 μm). The soils of the southern part, on the other hand, contained larger amounts of fine-grained quartz (2-20 μm). All the soils of the mountain range contained substantial amounts of volcanic glass in their sand fraction. However, on a total soil basis, the amount of volcanic glass in the soils decreased from the north to the south of the mountain range and the trend was parallel to that of the sand content of the soils. From these results, we concluded that (i) the soils of the northern and central parts of the mountain range were derived mainly from tephras and (ii) the soils of the southern part were strongly influenced by long-range eolian dust.     

Retention of mercury by soils

During the past one and a half decades there has been a marked increase in the total amount of mercury applied to the crop for control of agricultural pests particularly rice blight. It seems likely that the accumulation of mercury in agricultural products and soils has been increased. FURUTANI and OSAJIMA (3.4.5) investigated the content of mercury in rice, fruits, and vegetables and inferred that the mercury in fond products is partly the residue of fungicides sprayed on crops, and partly due to absorption from the soil by plant roots.