Mechanisms of increase in content of water-soluble P in Hachirogata reclaimed soils after NaCl washing

Abstract

In some of the drainage waters in Hachirogata reclaimed land, a very high concentration of inorganic P (up to 2 mg P L^-1) has been recently detected (Sato et al. unpublished). The drainage waters flow into the Lake Hachirogata that surrounds the land. Since the lake is also a reservoir, the water circulates through a closed system. Recently, the eutrophication of the lake has been found to be significant (Akita Prefectural Government 1989) and drainage water has been incriminated as one of the P sources of eutrophication. Therefore, it would be important to analyze the mechanisms responsible for the increase of P release from Hachirogata reclaimed land.     

Micromorphology of a clayey Bs horizon in an ash-derived podzolic soil from shimokita peninsula in northeastern Japan

It is well known that most developed Podzols or Spodosols occur on coarse- textured materials with a low content of weatherable minerals (Duchaufour 1977; McKeague et al 1983). In the Podzols derived from such parent material*. the th and/or Bhs horizons show definite evidence of illuviation characterized by continuous cementation, presence of cracked coatings on sand grains, and/or distinct dark pellets, These features were, therefore, adopted as the morphological criteria for spodic horizons in the Soil Taxonomy (Soil Survey Stalt 1975). The problem is to determine whether such criteria can be applied to Podzolic soils derived from volcanic ash which consists of fine, weatherable minerals.     

Fundamental studies on the physiology of rotifers in mass culture—V. Dry Chlorella powder as a food for rotifers

The dietary value of dried, commercial Chlorella was compared with that of living marine Chlorella, and yeast, in relation to growth of the rotifer Brachionus plicatilis raised individually and by batch culture methods.A concentration of 50 μg/ml of dried Chlorella powder is near an optimal density for rotifer growth. The dried material in suspension is less effective for growth than living marine Chlorella, although it is much more effective than a suspension of yeast at the same density (50 μg/ml).In batch culture (12-l glass vessel), the rotifers grew from an initial inoculation of 13.2 individuals/ml to a density of 434 individuals/ml by the 16th day. About 10⁷ rotifers could be removed from one batch culture in five harvests in the 41-day experimental period.The results indicate that dried Chlorella powder is an effective food for the rotifer Brachionus plicatilis.     

Structure and possible function of <Emphasis Type="Italic">N</Emphasis>-glycans of an invertebrate C-type lectin from the acorn barnacle <Emphasis Type="Italic">megabalanus rosa</Emphasis>

ABSTRACT:   A C-type lectin (BRA-2) isolated from the acorn barnacle Megabalanus rosa , which was a glycoprotein having an N -linked sugar chain, was deglycosylated by N -glycopeptidase F. The structure of the released sugar chains was determined by a 2-D mapping method after derivatization with a fluorescent reagent, 2-aminopyridine, to be Manα1-6(Manα1-3)Manβ1-4GlcNAcβ1-4(Fucα1-6)GlcNAc and Manα1-6(GlcNAcβ1-2Manα1-3)Manβ1-4GlcNAcβ1-4(Fucα1-6)GlcNAc. The structures were confirmed by matrix-assisted laser desorption ionization mass spectrometry and a comparison with authentic sugar chains by high-pressure liquid chromatography. Various properties of BRA-2 were examined before and after deglycosylation. The susceptibility of BRA-2 to protease digestion was increased by deglycosylation. However, the inhibitory activity toward calcium carbonate crystallization as well as the hemagglutinating activity of deglycosylated BRA-2 was significantly decreased. These results suggest that the sugar chains of BRA-2 are important to both its structural stability and its function.     

Development of an emulsion prepared with lipophilized gelatin and its application for hormone administration in the Japanese eel Anguilla japonica

A new water-in-oil-in-water (W/O/W) type emulsion using lipophilized gelatin (LG) and cotton-seed oil was developed for a novel method of hormone administration in fishes. LG was prepared by attaching palmitic anhydride to gelatin. The best conditions for preparing stable emulsions were determined where the final concentrations of LG in the emulsion and the volume ratio of LG solution to cotton-seed oil were 2% and 1:2, respectively. Hormone releasing properties of LG emulsion were compared with a water-in-oil (W/O) type emulsion prepared with Freund's incomplete adjuvant (FIA) and saline solution by monitoring plasma profiles of salmon gonadotropin (sGtH) II in the Japanese eel. sGtH II is gradually released from the LG emulsion. LG emulsion had hormone-releasing properties different from those of the saline solution and the FIA emulsion. Immature female Japanese eel (BW, 566 to 1017 g) received a weekly intramuscular injections (total of 10 injections) of the LG emulsion, the FIA emulsion or the saline solution, each of which contained sGtH fraction. The LG emulsion was found to be more effective in inducing ovarian maturation. In mature eel, final maturation and ovulation could be induced by simultaneous administration of sGtH fraction and 17-hydroxyprogesterone using LG W/O/W emulsion.     

Retrospective surveillance of metabolic parameters affecting reproductive performance of Japanese Black breeding cows

This retrospective study was conducted to confirm the relationship between pre- and postpartum metabolic parameters and postpartum reproductive performance and to clarify seasonal characteristics of the metabolic parameters by using our metabolic profile test (MPT) database of Japanese Black breeding herds. In evaluation 1, MPT databases of blood samples from multiparous cows collected prepartum and postpartum were divided into two groups according to calving interval, and each MPT parameter was compared. In evaluation 2, the same MPT databases used in evaluation 1 were divided into two groups according to the sampling period. Significant differences were found in the prepartal total protein and postpartal γ-glutamyltransferase in evaluation 1. In evaluation 2, significant differences were found in the prepartal and postpartal total protein, albumin/globulin ratio, and glucose. Clear seasonal differences in MPT results emphasized the usefulness of the MPT in breeding cattle herds fed home-pasture roughage and suggest that unsatisfactory reproductive performance during hot periods reflects inadequate nutritional content of the diet and possible reduced feed intake due to heat stress.     

Effect of cashew nut shell liquid on metabolic hydrogen flow on bovine rumen fermentation

Effect of cashew nut shell liquid (CNSL), a methane inhibitor, on bovine rumen fermentation was investigated through analysis of the metabolic hydrogen flow estimated from concentrations of short‐chain fatty acids (SCFA) and methane. Three cows were fed a concentrate and hay diet without or with a CNSL‐containing pellet. Two trials were conducted using CNSL pellets blended with only silica (trial 1) or with several other ingredients (trial 2). Methane production was measured in a respiration chamber system, and energy balance and nutrient digestibility were monitored. The estimated flow of metabolic hydrogen demonstrated that a part of metabolic hydrogen was used for hydrogen gas production, and a large amount of it flowed into production of methane and SCFA in both trial 1 and 2, when CNSL was administered to the bovine rumen. The results obtained by regression analyses showed that the effect of CNSL supply on methane reduction was coupled with a significant (P < 0.01) decrease of acetate and a significant (P < 0.01) increase of propionate and hydrogen gas. These findings reveal that CNSL is able to reduce methane and acetate production, and to increase hydrogen gas and propionate production in vivo.     

Effects of the estrous cycle on the efficacy of oocyte collection and in vitro embryo production in Duroc‐breed

Collection efficacy and in vitro embryo developmental ability of oocytes obtained from Duroc‐breed ovary donors at different stages of the estrous cycle (days 6, 12 and 16 after estrus) were performed. The numbers of collected oocytes did not differ significantly among the different estrous cycle groups (total 72–90 oocytes per gilt). However, the blastocyst rates of oocytes collected on days 12 and 16 (9.2% and 19.4%, respectively) were significantly higher than those on day 6 (1.1%). More oocytes were obtained on day 16 from small follicles (<2 mm in diameter; 85.3 oocytes per gilt) than from medium‐sized (≥2–<6 mm) and large (≥6 mm) follicles (17.5 and 12.8 oocytes, respectively). The blastocyst rates in both the medium‐sized and large follicle groups (20.0% and 19.2%, respectively) were significantly higher than that in the small follicle group (6.3%). The blastocyst cell numbers in both the medium‐sized and large follicle groups (39.4 and 43.3 cells, respectively) were significantly higher than that in the small follicle group (30.6 cells). The results suggest that oocyte collection from cycling Duroc pigs can be carried out efficiently from the late luteal to follicular stage. Those oocytes collected from medium‐sized and large follicles show better embryo development.