Prevalence of hemoplasma infection among cattle in the western part of Japan

We have examined for hemoplasma infection among cattle in the Hiroshima and Miyazaki prefectures by using a sensitive real-time PCR, with SYBR Green I and with melting curve analysis, which allow to distinguish the two bovine hemoplasma species, Mycoplasma wenyonii and 'Candidatus M. haemobos'. We found 69.4% of 36 cattle in Hiroshima and 93.8% of 32 cattle in Miyazaki infected with either of these two hemoplasma species. High morbidity in western part of Japan may reflect the activity of arthropod vectors for hemoplasma transmission. We also demonstrated neonatal calves less than three months old affected with hemoplasmas without grazing in summer, suggesting a possibility of vertical transmission.     

Historical Profiles of Trace Element Concentrations in Mangrove Sediments from the Ba Lat Estuary,Red River,Vietnam

Historical profiles of trace element concentrations were reconstructed from two mangrove sediment cores collected within the Ba Lat Estuary (BLE), Red River, Vietnam. Chronologies of sediment cores were determined by the ²¹⁰Pb method, which showed that each respective sediment core from the south and north entrances of BLE provided a record of sediment accumulation spanning approximately 100 and 60 years. The profiles of Pb, Zn, Cu, Cr, V, Co, Sb, and Sn concentrations markedly increased from the years of the 1920s–1950s, and leveled out from 1950s–1980s, and then gradually decreased from 1980s to present. The profiles of Cd and Ag concentrations increased from 1920s–1940s, and then decreased from 1940s to present. The profile of Mo concentrations progressively increased from 1920s–1980s, then decreased to present. The Mn concentrations failed to show a clear trend in both sediment cores. Results from contamination factors, Pearson’s correlation, and hierarchical cluster analysis suggest that the trace elements were likely attributed to discharge of untreated effluents from industry, domestic sewage, as well as non-point sources. Pollution Load Index (PLI) revealed levels higher than other mangrove sediment studies, and the long-term variations in PLI matched significant socioeconomic shifts and population growth in Vietnam. Geoaccumulation Index showed that mangrove sediments were moderately polluted by Pb and Ag, and from unpolluted to moderately polluted by Zn, Cu, and Sb. The concentrations of Pb, Zn, Cu, Cr, and Cd exceeded the threshold effect levels and effect range low concentrations of sediment quality guidelines, implying that the sediments may be occasionally associated with adverse biological effects to benthic organisms.     

Changes in the stand structure of a pine forest after rapid growth of Quercus serrata Thunb.

We studied the species composition and stand structure of secondary pine forests affected by pine wilt disease, caused by epidemic attacks of the nematode Bursaphelenchus xylophilus, in western Japan. Based on the species composition, the vegetation was divided into four types: (1) Cladonia rangiferina, (2) Wikstroemia sikokiana, (3) Quercus glauca, and (4) Gleichenia japonica. The sequence of types from (1) to (3) represents a successional series in accordance with topographical position. The relative basal areas of Rhododendron reticulatum and Juniperus rigida in the C. rangiferina and W. sikokiana types were larger than in the Q. glauca type. The relative basal areas of Q. serrata, Clethra barbinervis, and Eurya japonica in the C. rangiferina and W. sikokiana types were less than in the Q. glauca type. The mortality of light-demanding trees was higher in the Q. glauca type than in the C. rangiferina and W. sikokiana types. In stands that were severely affected by pine wilt disease, light was reduced and soil became moist after rapid growth of Q. serrata and other species which are not affected by the disease. The numbers of species and components of evergreen broad-leaved natural forests were decreased, because pine forests in the study area had been cut frequently and the land had degraded. Pine wilt disease has shifted the dominance of pine forests from Pinus densiflora to deciduous oaks such as Q. serrata and physical conditions seemed to provide a safe site for shade-tolerant plant species, which are components of evergreen broad-leaved forests. Moreover, the seed dispersal of evergreen oaks appears to be an important factor in the succession to evergreen broad-leaved forest in degraded areas.     

Temporal and spatial change in phosphate–phosphorus concentration and modeling with land-use variation in Sengari reservoir basin,Japan

Paddy and Water Environment - Severe degradation of water quality from nutrient pollutants has increased eutrophication that affects aquatic ecosystems and increases the cost of water treatment....     

Ontogeny of swim bladder inflation and caudal fin aspect ratio with reference to vertical distribution in Pacific bluefin tuna Thunnus orientalis larvae

It is necessary to understand the processes involved in sinking death in Pacific bluefin tuna Thunnus orientalis aquaculture in order to develop methods to prevent or minimize this problem. We observed the nighttime vertical distribution of Pacific bluefin tuna in the water column on 2–9 DAH and the morphological characteristics of the larvae, in order to clarify the processes involved in sinking death. A cuboid tank (height 300 cm) was used to measure vertical distribution. The number of larvae was counted in each of 4 regions in the observation tank: upper layer (water depth 0–100 cm), middle layer (100–200 cm), lower layer (200–300 cm), and bottom area. The distribution of larvae in these regions at 4 days after hatching was polarized to the upper layer and bottom area. Individuals with inflated swim bladders were observed in the upper layer 3 days after hatching. No larvae with inflated swim bladders were observed in the bottom area on any day after hatching. Total body length and caudal fin aspect ratio of larvae with both inflated and un-inflated swim bladders were greater in the upper layer than those of larvae in the bottom area. Larvae with un-inflated swim bladders that failed to develop sufficiently for swimming sank to the tank bottom and died. Swim bladder development and caudal fin swimming ability are strongly related to sinking death.     

Electroretinography using contact lens electrode with built-in light source in dogs

Electroretinography (ERG) is an effective method for the diagnosis of retinal disease. In the dog, dependable ERG recording is difficult without the use of an expensive device like a Ganzfeld full-field stimulator. The International Society for Clinical Electrophysiology of Vision has defined the standard flash stimulus condition (SF) and evaluation of the retina using the b/a ratio in humans. In dogs, evaluation using the b/a ratio has not been reported, whereas the intensity of SF has been defined. In this study, we performed a convenient ERG recording method using a contact lens electrode with a built-in light source (LED-electrode), and confirmed SF as reported previously. ERG recordings were performed on 15 healthy beagle dogs under sedation. We performed bilateral ERG at 12 different intensities after 30 min dark adaptation. After 10 min light adaptation, we recorded single flash cone and flicker cone response using the SF determined in this study. In this study, SF of 3.0 cd/m(2)/sec (6,000 cd/m(2), 0.5 msec) resulted in b/a=2. The intensity for rod response that recorded only the b-wave was 0.0096 cd/m(2)/sec (80 cd/m(2), 0.12 msec). We could achieve ERG for each response easily and smoothly under sedation, and without general anesthesia. Using an LED-electrode, we could perform more quantitative and reproducible ERG examinations than with traditional methods. We propose that the b/a ratio is the most useful parameter in ERG reporting for evaluating retinal function.     

Establishment of feather follicle stem cells as potential vehicles for delivering exogenous genes in birds

The present study was performed to develop a culture system for feather keratinocyte stem cells to enable the genetic manipulation of endangered avian species. The feather follicle cells were isolated from growing feathers of adult White Leghorn chicken. Leukemia inhibitory factor (LIF) was used to maintain the characterization of the keratinocyte colony-forming cells (KCFCs). The EGFPN1 plasmid DNA retroviral vector was used to deliver Green Fluorescent Protein (GFP) gene, which was introduced to the KCFCs by lipofection. After removal of the fibroblast-like cells, the feather KCFCs attached to the substrate within 24 h of seeding. The cells continued to proliferate for at least 30 days in the presence of LIF. The cell-adhesion molecules such as integrin beta1 and CD49c were immunocytochemically positive in the cells. The KCFCs differentiated into barbular cells and pennaceous feather vane in the LIF-free medium. The GFP gene-transfected KCFCs stably expressed GFP. The present results indicate that the KCFCs derived from feather follicles are closely related to multipotent stem cells. In addition, gene manipulation of such stem cells may be useful for the production of chimera in avian species.     

Changes of proximate composition and extractive components in narezushi, a fermented mackerel product, during processing

ABSTRACT:   During the processing of mackerel narezushi , the fish body was strongly dehydrated by permeation of salt, the low pH of fish meat, and pressure applied to the fish and rice mixture. In the proximate components, moisture, protein and lipid flowed out from the fish meat into the rice mixture, and sugar permeated from the rice mixture into the fish meat. That the total amount of outflow was larger than that of permeation into the fish is thought to contribute to the decrease in fish body weight during processing. In the extractive components, although the nucleotides completely decomposed, free amino acids and peptides increased remarkably because of the decomposition of proteins in fish meat during processing. Especially, six kinds of free amino acid, Glu, Asp, Gly, Ala, Leu, and Ile, which are thought to be the taste components in marine resources, increased. Organic acid increased remarkably because of the fermentation of rice and permeation into the fish meat. The marked increase of the extractive components is thought to contribute to the umami taste and the sour taste of narezushi .