Effect of dexamethasone on the expression of atrogin‐1/MAFbx in chick skeletal muscle

Expression of atrogin‐1/MAFbx, a muscle‐specific E3 ubiquitin ligase, is high under catabolic conditions, that result in muscle atrophy. Messenger RNA (mRNA) expression of atrogin‐1/MAFbx is increased by the glucocorticoid dexamethasone in mammalian skeletal muscle. This study investigated the effects of dexamethasone on expression of atrogin‐1/MAFbx in skeletal muscle of neonatal chicks and in chick myotubes. Chicks were given a single intraperitoneal injection of dexamethasone at a concentration of 10 mg/kg body weight. Twenty‐four hours after dexamethasone administration, the Pectoralis muscle weight of chicks was decreased. mRNA expression of atrogin‐1/MAFbx in skeletal muscle of chicks was significantly increased by dexamethasone administration. Expression of other proteolytic‐related genes (20S proteasome C2 subunit, m‐calpain large subunit, and cathepsin B) in skeletal muscle of chicks was not increased by dexamethasone administration. Chick myotubes were incubated with dexamethasone (1, 10 or 100 µmol/L) for 6 h. Expression of atrogin‐1/MAFbx mRNA in chick myotubes was increased in the presence of all concentrations of dexamethasone. However, expression of other proteolytic‐related genes (20S proteasome C2 subunit, m‐calpain large subunit and cathepsin B) in chick myotubes was not affected by dexamethasone treatment. These results indicate that dexamethasone enhances atrogin‐1/MAFbx expression in chick skeletal muscle, resulting in increased muscle atrophy.     

Genotyping of isolates ofTaylorella equigenitalis from thoroughbred brood mares in Japan

Profiles of the genomic DNA of 104 strains ofT. equigenitalis isolated from brood mares with contagious equine metritis in Hokkaido during the breeding seasons from 1980 to 1993, as well as those of five strains (SS28, EQ56, EQ59, EQ70 and HH139) previously isolated in Japan were examined after restriction digestion and crossed-field gel electrophoresis. These profiles were essentially identical to each other and the various isolates and strains appeared to have a common genotype, designated genotype J, with respect to two restriction enzymes,ApaI andNotI. These results suggest a common source for all these isolates obtained over the course of more than 10 years in Japan.Abbreviations CEM contagious equine metritis - CFGE crossed-field gel electrophoresis - PFGE pulsed-field gel electrophoresis     

Ultrastructure of fibroblasts from the comb of the cockerel

1. Fibroblasts in the intermediate layer of comb dermis of intact single‐combed White Leghorn cocks and testosterone‐injected capons, all 82 days of age, were divided into three types, namely A, B and C, according to the ultrastructure of these cells. All the fibroblasts in the same tissue from capons were type C.

2. The Golgi complex and the rough endoplasmic reticulum were well developed in type A and type B fibroblasts. The latter organelle in type A fibroblasts was in the form of long parallel cisternae spaced a uniform distance apart, while that in type B fibroblasts was extremely distended, branched and anastomosed, containing flocculent material in the cisternae. In type C fibroblasts, both the Golgi complex and the rough endoplasmic reticulum were poor.     

Progressive Langerhans' cell histiocytosis in a puppy

A 8-month-old, female miniature Dachshund dog was presented for the complaint of pruritic, generalized, multiple nodules and plaques. Two months previously, a nodule on the left pinna was excised and diagnosed as a cutaneous histiocytoma. One month post-excision, a nodule reappeared at the same site and, shortly thereafter, additional nodules developed. Histopathological examination revealed a diffuse proliferation of histiocytic cells, which reacted strongly to antibodies for vimentin and lysozyme. Immunophenotypic analysis showed that most of the cells expressed CD1a, CD1c, CD11c, CD18, CD45 and MHC class II markers. Electron microscopic examination revealed cytoplasmic filopodia and paracrystalline structures. These findings indicated that the cells originated from Langerhans' cell. The disease progressed despite glucocorticoid therapy and griseofulvin was administered as an immunomodulating drug. All lesions resolved completely after 7 weeks of griseofulvin treatment. The dog, however, died three months later after discontinuation of griseofulvin therapy and a necropsy was not performed. It is considered that the present canine dermatosis corresponds with a severe form of Langerhans' cell histiocytosis in humans rather than canine cutaneous histiocytoma.     

Improvements in a simple harmonic analysis of groundwater time series based on error analysis on simulated data of specified lengths

Tidal response method is an efficient technique for investigating hydraulic properties of an aquifer in insular and coastal areas of highly permeable geological settings. The present study extends a simple and straightforward harmonic-analysis technique recently introduced as part of a tidal response method applied to a freshwater-lens aquifer. This simple analysis technique was examined with artificially synthesized time series composed of multiple realistic tidal components. The analysis outputs of major diurnal and semidiurnal components are sufficiently accurate if the analyzed time-series length is appropriately restricted. Limitations of the simple harmonic analysis in the applicable time-series length arise from tidal-component interference that occurs in analyses over a finite length. Definitively recommended simple harmonic-analysis technique with appropriate combinations of time-series lengths and extractable tidal components are convenient for investigating hydraulic properties of an aquifer, such as on a remote island where the freshwater lens is the only freshwater resource.     

Effects of tillage and irrigation on the occurrence and establishment of native wetland plant species in fallow paddy fields

Traditional weed management, such as tillage and irrigation, has led to an enhanced maintenance of wetland plant species in fallow paddy fields. Recent herbicide usage and improvements in irrigation and drainage systems however have caused habitat loss of these species, especially in fields on open lowlands. We conducted experiments in three fallow paddy fields situated on the alluvial Echigo Plain in central Japan with an aim to restore the habitat of native wetland plant species. The three experimental fields were managed under different irrigation regimes, (1) perennially flooded with water, (2) intermittent irrigation, and (3) temporary irrigation. Half the area of each experimental field was tilled before irrigation. Detrended correspondence analysis revealed obvious floristic differences between experimental and control fields with no irrigation. The proportion of wetland plant species in the experimental fields increased corresponding to the irrigation period, ranging 60–86%, and was relatively greater than that in control fields. In the experimental fields, differences in both tillage and irrigation affected the occurrence of plant species. Tillage restricted the occurrence of many non-wetland plant species, and had a positive effect on the establishment of several annual wetland plant species. In addition, a longer duration of irrigation is not necessarily suitable for the occurrence of all wetland plant species. We concluded that fallow paddy fields provide a possible habitat for the restoration of native wetland plant species through appropriate tillage and irrigation.     

Distribution patterns of larval myctophid fish assemblages in the subtropical–tropical waters of the western North Pacific

We examined larval myctophid fish assemblages and their distribution patterns, based on discrete depth sampling. Samples were collected at 19 stations along a transect that crossed the subtropical–tropical waters of the western North Pacific. In total, we collected 27 189 larvae of 40 myctophid species or types, belonging to 15 genera. Three assemblages were recognized, based on their species composition: Kuroshio Axis (KuA), Kuroshio Countercurrent (KCC), and Subtropical Countercurrent–North Equatorial Current (SCC–NEC) assemblages. The distributions of these assemblages were well defined by the positions of the KuA and the Subtropical Convergence. Each species had a specific distribution depth, and none showed diel vertical migration. Larvae of the subfamily Lampanyctinae were distributed in shallower waters (0–50 m) than larvae of the subfamily Myctophinae (50–150 m). Larvae of the same species were distributed at lower depths in the SCC–NEC area than in the KCC area. This corresponded to the abundance of chlorophyll a, which would reflect abundance of prey organisms such as copepod nauplii and copepodites.     

National-scale variations in the stable isotopic compositions of irrigation-pond and spring waters across Japan

Paddy and Water Environment - The national-scale variations and regional characteristics of the stable isotopic compositions of irrigation ponds, which are small reservoirs for irrigating paddy...     

Preparation of nori Pyropia yezoensis enriched with free amino acids by aging the culture with nori koji

Koji is commonly used in manufacturing Japanese fermented products and promotes enzymatic degradation. In recent years, a seaweed koji has been developed by culturing Aspergillus oryzae on nori Pyropia yezoensis. In the present study, we prepared nori koji by culturing A. oryzae on high- and low-quality noris and then mixing this preparation with additional dried nori. Suitable fermentation conditions for increasing the taste-active components of the nori mixed with nori koji were investigated. The mixture of nori and koji prepared from high-quality nori, with added water, cultured for 120 days at 10 °C, provided the greatest increase (7 times) in free amino acids. The changes in taste after culturing the nori and koji mixture were evaluated using a taste-sensing system. The sourness score of the nori and koji mixture increased significantly, but the scores for other attributes such as bitterness and umami richness did not increase after culture. The present study has demonstrated a clear increase in the free amino acid content of nori and a modification in the taste score by aging the culture with nori koji. These results will encourage the development of ‘aged seaweed,’ a novel value-added product with nutritional and taste elements modified using seaweed koji.