Interannual variability in stock abundance of the neon flying squid, Ommastrephes bartramii, in the North Pacific Ocean during 1979–1998: impact of driftnet fishing and oceanographic conditions

Variability in catch-per-unit-effort (CPUE) was examined for the autumn cohort of Ommastrephes bartramii collected with research driftnets during 1979–1998 along five longitudinal transects passing through the Subarctic, Transitional and Subtropical Domains in the North Pacific. CPUE was generally low during the period of intensive commercial driftnet fishing (1980–1992) and increased following the 1992 moratorium on the use of large-scale driftnets. However, CPUE levels were low for the cohorts hatched in 1992 and 1996 (captured in subsequent years owing to a one-year life of O. bartramii ) that experienced low sea surface temperatures from hatching to recruitment. Among similar-aged squid collected from 180° and 179°30'W in June, mantle lengths were significantly greater in 1997 than during 1995–96. These findings suggest that the driftnet fishery and sea surface temperatures from hatching to recruitment strongly affected stock abundance and possibly growth.     

A rat model for the energetic regulation of gonadotropin secretion: role of the glucose-sensing mechanism in the brain

Energy availability has been considered to regulate gonadal activity by modulating the release of gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) at various reproductive phases, such as lactation and puberty in domestic as well as wild animals. Experimental models with rats and sheep have demonstrated that fasting or glucoprivation suppresses pulsatile LH release. From those experiments, the information on energy deficiency is considered to be detected by specific central sensors and conveyed to the hypothalamus to regulate LH release as well as food intake. Noradrenergic neurons, originating in the medulla oblongata and projecting to the hypothalamic paraventricular nucleus (PVN), is reported to be one of the pathways mediating the response of LH release to energy deficiency. The other component is considered to be an energy-sensing mechanism in the brain. Glucose or other oxidizable fuels may function as a metabolic signal to regulate LH release. Previous studies suggest the presence of a glucose-sensing mechanism in the rat hindbrain. From our previous results in the rat, the ependymocytes lining the wall of the cerebroventricle could possibly serve as a glucose sensor to regulate GnRH/LH release. Greater understanding of the nature of the energy-sensing mechanism in the brain will contribute to the nutritional manipulation of reproductive performance in domestic animals in various conditions.     

Aloe ring spot,a new disease of aloe caused by <Emphasis Type="Italic">Haematonectria haematococca</Emphasis> (Berk. &; Broome) Samuels &; Nirenberg (anamorph: <Emphasis Type="Italic">Fusarium</Emphasis> sp.)

A ring spot disease of Aloe vera was found on leaves of potted seedlings of Aloe vera in Hachijojima and Chichijima Islands, Tokyo. From tissue of ring spot lesions, a fungus producing Fusarium-type conidia was consistently isolated. After 1 month, reddish perithecia of nectriaceous fungus had formed on the colonies of this isolate on PDA. These nectriaceous and Fusarium fungi were identified as Haematonectria haematococca and Fusarium sp., respectively. From a single ascospore isolation, the former was confirmed to be the teleomorph of the Fusarium sp. Typical ring spot lesions were reproduced by artificial inoculations using single ascospore and single conidium isolates. Inoculations of five species of genus Aloe revealed that they were highly susceptible except for A. arborescens. This is the first report of a disease on Aloe caused by H. haematococca (anamorph: Fusarium sp.) in Japan, and it was named aloe ring spot.     

Temporal and spatial dynamics of an old-growth beech forest in western Japan

Dendrochronological approaches enable us to understand forest stand dynamics by estimation of disturbance history and age structure. The present study was conducted in an old-growth beech forest in a forest reserve in western Japan. Increment cores were taken for tree ring analysis from all canopy trees in a 50 m × 130 m study plot. Radial growth release criteria were developed to identify significant growth releases in each tree ring series and to characterize the disturbance history of the study site. The age structure of the forest was indicative of continuous establishment by Fagus crenata and simultaneous establishment by Magnolia obovata. A variety of low-intensity disturbances were identified in each decade, especially after the 1900s, but the occurrence of high-intensity catastrophic disturbance was rare, and likely played an important role in maintaining species diversity in the existing forest canopy. The results also suggest that F. crenata regenerates gradually before and after both large- and small-scale disturbances, whereas M. obovata and Betula grossa regenerate only after large-scale catastrophic disturbances.     

Reddish coloration of Chinese quince (Pseudocydonia sinensis) procyanidins during heat treatment and effect on antioxidant and antiinfluenza viral activities

To investigate the effects of processing Chinese quince fruit on the denaturation of phenolics and their food functions, fruit phenolic extracts were heated together with organic acid for up to 12 h. Chinese quince phenolic (mostly procyanidins) solution subjected to heat treatment changed from almost colorless, pale yellow, to a reddish color. Before heat treatment, the absorption spectra of polymeric procyanidins were observed only around 280 nm; after heat treatment, absorption occurred between 400 and 600 nm, which is related to the reddish color appearance. Thioacidolysis of denatured reddish phenolics showed that (-)-epicatechin subunits decreased during heat treatment and, in contrast, cyanidin increased. In addition, novel substances that could not be degraded by thioacidolysis were formed. Meanwhile, antioxidant activities, assessed by linoleic acid peroxidation, 1,1-diphenyl-2-picrylhydrazyl (DPPH), Folin-Ciocalteu, and FRAP methods, increased during heat treatment. The antiinfluenza viral activity of denatured reddish phenolics was inferior to that of intact fruit phenolics; however, they retained moderate activity. These results indicate that red coloration of fruit products of Chinese quince was mainly due to the spectral (i.e. structural) changes of procyanidins accompanied with formation of cyanidin. Increasing the length of heat treatment increased the antioxidant capacity of phenolics, and the resultant reddish phenolics retained moderate antiinfluenza viral activity.     

cDNA cloning and characterization of the warm-temperature-acclimation-associated protein Wap65 from carp, Cyprinus carpio

We determined full-length cDNA of carp warm-temperature-acclimation-associated 65-kDa protein (Wap65). It encoded 439 amino acid residues with a signal peptide of 22 residues and showed an amino acid sequence identity of 88% to that of goldfish reported before (J. Biol. Chem. 1995. 270: 17087–17092). The number of potential N-linked glycosylation sites of carp Wap65 was two in contrast to three for goldfish. In addition, molecular mass determined by SDS-PAGE was apparently different from that of goldfish. These results suggest that the amount of oligosaccharide is different between the carp and goldfish protein. As in goldfish, carp Wap65 mRNA showed marked accumulation in hepatopancreas of the 30 °C- acclimated fish, which was 8-fold higher than that of the 10 °C-acclimated fish. Carp Wap65 showed 30% amino acid identity to mammalian hemopexins, which appeared to be considerably low in comparison with those among mammalian hemopexins (72 to 80%), or among carp Wap65 and rainbow trout hemopexin-like protein (70%). However, although mammalian hemopexins contain residues comprising the heme binding pocket, carp Wap65 lacked one of the two histidine residues to serve as heme axial ligands in hemopexins. Our data on carp protein substantiates the previous observation for goldfish and indicates that Wap65 might have some important functions in warm-temperature-acclimation of fish.