Daily growth increment formation and its lunar periodicity in otoliths of the myctophid fish Myctophum asperum (Pisces: Myctophidae)

ABSTRACT: The surface-migratory myctophid fish, Myctophum asperum , of the western North Pacific was found to have daily growth increments of its sagittal otolith, which also exhibited lunar periodicity in the deposition of increments. Daily deposition of the otolith increments was verified because the width of the marginal increment increased during the night and early morning between 20.00 h and 08.00 h and its growth stopped during the day. An autocorrelation analysis of the increment widths, which were measured consecutively in 11 specimens covering 33 synodic months, also showed a lunar periodicity in increment deposition. The mean increment widths during five days around the time of a full moon were significantly narrower than those around a new moon in 18 of the 33 full moon cases ( P < 0.01: Student's t -test) and, on average, tended to be narrow in 29 cases. The cause of this tendency is thought to be slower growth caused by staying in deeper and colder habitat due to the suppression of diel vertical migration and/or lower food availability resulting from the possible dispersion of zooplankton during the full moon period.     

Histochemical identification of oestrogen target cells in the medullary bone of laying hens

1. Oestrogen target cells in the medullary bone of laying hens were examined using a histochemical method with fluorescein isothiocyanate labelled oestradiol. 2. Specific fluorescence was found to occur strongly in osteoblasts and weakly in osteoclasts on the medullary bone surface. 3. This study suggests that osteoblasts on the medullary bone surface are oestrogen target cells.     

Identification of tropomyosin as a major allergen in the octopus Octopus vulgaris and elucidation of its IgE-binding epitopes

ABSTRACT: The major allergen (named Oct v 1) in the muscle of the octopus Octopus vulgaris was purified by gel filtration on Sephacryl S-300, anion-exchange fast protein liquid chromatography on Mono Q and reverse-phase high-pressure liquid chromatography on TSKgel Octadecyl-4PW. In addition to the molecular mass, amino acid composition and cross-reactivity with Tur c 1 (turban shell Turbo cornutus allergen), the determined partial amino acid sequence clearly demonstrated that Oct v 1 is tropomyosin, similar to the known molluscan and crustacean allergens. Using peptide fragments isolated from the lysylendopeptidase digest of Oct v 1, competitive enzyme-linked immunosorbant assay inhibition experiments showed that IgE-binding epitopes of Oct v 1 are contained in two peptides (77–112 and 148–160) in the central region and one peptide (269–281) in the C-terminal region. In the peptide 77–112, the same sequence as the IgE-binding epitope proposed for Cra g 1 (oyster Crassostrea gigas allergen) is recognized at 92-105. Moreover, the peptide 148-160 partly overlaps with the IgE-binding epitopes suggested for Pen i 1 (shrimp Penaeus indicus allergen) and Pen a 1 (shrimp Penaeus aztecus allergen), and the peptide 269–281 with those for Tur c 1 and Pen a 1.     

Survey of coccidial oocysts and parasite eggs in feces of free-ranging Grus japonensis

Fecal survey of Eimeria oocysts and parasite eggs was conducted for 219 fecal samples of free-ranging Grus japonensis in Kushiro district in Hokkaido in April 2003. Positive rate and mean oocysts (or eggs) per gram in positive samples were 26% (57/219) and 8.8 (0.2-136) in oocysts of Eimeria reichenowi, 18.3% (40/219) and 320 (100-1,000) in trematode eggs, 0.1% (2/219) and 0.2 (0.2-0.3) in eggs of Nematoda A, and 4.1% (9/219) and 0.8 (0.2-3.6) in eggs of Nematoda B, respectively.     

Influence of weed management measures on glyphosate resistance and endophyte infection in naturalized Italian ryegrass (Lolium multiflorum)

Recently, glyphosate‐resistant Italian ryegrass (Lolium multiflorum Lam.) was found on rice paddy levees in a western region of Shizuoka Prefecture, Japan. Naturalized populations of Italian ryegrass are frequently infected with fungal Epichloë endophytes. Endophytes often confer benefits to their host grasses. This study investigated the influence of five weed management treatments on glyphosate resistance and endophyte infection in Italian ryegrass that was growing on paddy levees where glyphosate‐resistant individuals were dominant. The weed management treatments were: (i) mowing once before the grass flowered; (ii) mowing once during flowering; (iii) mowing twice during flowering; (iv) glyphosate application before flowering; and (v) no treatment. The seeds were collected from the treatment plots in 2013 and 2014. The seeds were examined for endophyte infection and the seedlings that had been grown from the seeds were tested for the frequency of glyphosate resistance. The seedlings that had been derived from the glyphosate treatment showed higher frequencies of glyphosate resistance than those seedlings that had been derived from all the other treatments. Endophytes were found in all populations of the seeds from the paddy levees, with higher infection rates in the seeds that had been derived from the glyphosate treatment and the twice‐mowed treatment. There was a significant relationship between the endophyte infection frequency in the seeds and glyphosate resistance in the seedlings that had been grown from the same populations. The results indicate that where glyphosate herbicides are frequently used, selection for glyphosate‐resistant Italian ryegrass occurs, and along with this, the frequency of endophyte infection also increases.