Accumulation of paralytic shellfish poisoning toxin by the swimming crab <Emphasis Type="Italic">Charybdis japonica</Emphasis> in Kure Bay,Hiroshima Prefecture

The accumulation of paralytic shellfish poisoning (PSP) toxin in the crab Charybdis japonica was investigated in Kure Bay, when a bivalve Mytilus galloprovincialis, in the same water, showed toxicity caused by PSP toxin. In 2005, 17 specimens of the crab had PSP toxin over 4 MU/g in the hepatopancreas, and the highest toxicity was at 37.4 MU/g. Since the regulation limit of PSP for crab hepatopancreas was set in 2004, this is the first observation of regulatory level of PSP toxin in C. japonica. Unlike in the hepatopancreas of the crab, the hazardous level of the toxin was not detected in the muscle of the cephalothorax and the appendage. The toxin accumulation in the crab was also investigated by feeding toxic mussels to the crab. The crab retained the toxin mainly in the hepatopancreas, and the ratio of retention in the crab was from 12.9 to 24.6%. The toxin profiles, shown in the feeding experiments, suggest that the transformation of PSP toxin occurs in the crab because dcGTX2 and dcGTX3 was detected in all crab specimens despite the lack of these analogs in the mussels used as feed.     

Age validation,growth and annual reproductive cycle of chub mackerel <Emphasis Type="Italic">Scomber japonicus</Emphasis> off the waters of northern Kyushu and in the East China Sea

The age and growth of chub mackerel Scomber japonicus collected from the East China Sea and the northern waters off Kyushu between June 2000 and June 2001 were determined by observing the otolith surface after dipping it in xylene. The translucent and opaque zones on the otolith surface were identified, and the number of translucent zones was counted. Monthly changes in the frequency of fish with translucent zones on the otolith margin, and in the marginal increments, indicated that the translucent zones were formed between April and June. The seasonal pattern of annulus formation on the otolith became clear by observing the otoliths of fish with known ages, and the otolith formation in wild fish was consistent with that of fish with known ages. The mean gonadosomatic index of male and female fish was high from March to May, and spawning females were observed from mid-March to mid-May. The estimated ages were 1–5 years for males and 1–6 years for females. The von Bertalanffy growth parameters did not significantly differ between male and female. The model was obtained as FL _t=406×{1−exp[−0.372×(t+1.68)]     

Effect of feeding non-fibrous carbohydrate before grazing on intake and nitrogen utilization in dairy cows throughout the grazing season

Ten lactating cows were used to determine the effect of feeding non-fibrous carbohydrate (NFC) supplement before grazing on feed intake and nitrogen (N) utilization throughout a grazing season. The experiment was conducted from June to September. Cows grazed twice a day (2.5 h × 2) under a set stocking system and were fed NFC supplement (1 kg/4 kg of milk yield) 2 h before grazing (PRE) or immediately after grazing (POST). Cows were also fed a grass and corn silage mixture ad libitum. Herbage dry matter intake (DMI) was greater for PRE than for POST throughout the experiment and decreased from June to September. Conversely, silage DMI was less for PRE than for POST throughout the experiment and increased over the grazing season. Consequently, total DMI for PRE did not differ from that for POST. Milk urea-N concentration and urinary urea-N excretion in June did not differ between the treatments, whereas that after July was higher for PRE than for POST. Proportion of urinary N excretion to absorbed N intake in June was lower for PRE than for POST, but that after July was higher for PRE than for POST. Feeding NFC supplement before grazing would improve N utilization when cows eat large amounts of herbage high in N.     

Comparison of quantity and structures of hydroxyproline-containing peptides in human blood after oral ingestion of gelatin hydrolysates from different sources

We compared quantity and structures of food-derived gelatin hydrolysates in human blood from three sources of type I collagen in a single blind crossover study. Five healthy male volunteers ingested type I gelatin hydrolysates from fish scale, fish skin, or porcine skin after 12 h of fasting. Amounts of free form Hyp and Hyp-containing peptide were measured over a 24-h period. Hyp-containing peptides comprised approximately 30% of all detected Hyp. The total area under the concentration-time curve of the fish scale group was significantly higher than that of the porcine skin group. Pro-Hyp was a major constituent of Hyp-containing peptides. Ala-Hyp, Leu-Hyp, Ile-Hyp, Phe-Hyp, and Pro-Hyp-Gly were detected only with fish scale or fish skin gelatin hydrolysates. Ala-Hyp-Gly and Ser-Hyp-Gly were detected only with fish scale gelatin hydrolysate. The quantity and structure of Hyp-containing peptides in human blood after oral administration of gelatin hydrolysate depends on the gelatin source.     

Identification of marker genes for intestinal immunomodulating effect of a fructooligosaccharide by DNA microarray analysis

Prebiotic fructooligosaccharides are noted for their intestinal immunodulating effects, and the identification of markers for the effects is a matter of great concern. This study aimed to identify marker genes for physiological effects of a particular fructooligosaccharide (FOS) on a host animal and also to define the target of its function in the small intestine. DNA microarray technology was used to screen candidate marker genes, and comprehensive changes in gene expressions in the ileum of mice fed with FOS were investigated. One of the major physiological effects of FOS was intestinal immunomodulation. Marker genes were then identified for major histocompatibility complex classes I and II, interferon, and phosphatidylinositol metabolites. Also, the ileum was segmented into Peyer's patch (PP) and the other ileal organ (DeltaPP), and these were analyzed by quantitative RT-PCR method, with the result that the site for recognizing the FOS function was the DeltaPP rather than the PP. This is the first paper showing the markers for the physiological effects of FOS in the small intestine at gene expression level. Applying these marker genes would make it possible to clarify the mechanisms of how the administration of dietary FOS and associated changes in the intestinal environment are recognized by host organisms as well as how its immunomodulating effects are expressed in the body.     

Effects of age, egg-laying activity, and Salmonella-inoculation on the expressions of gallinacin mRNA in the vagina of the hen oviduct

Gallinacins (Gal) are antimicrobial peptides that play significant roles in innate immunity in chickens. The aim of this study was to examine whether age of birds and egg-laying activity (laying and non-laying caused by feed-regulation) affect the mRNA expression of Gal-1, -2, and -3 in the vagina of hens, and whether their expressions are changed in response to the stimulation with Salmonella enteritidis (SE) and lipopolysaccharide (LPS). White Leghorn hens were divided into groups of young and old laying hens, and groups of laying and non-laying hens after feed-regulation. Vaginal cells were cultured and stimulated with SE or LPS. Expressions of Gal-1, -2, and -3 mRNA in their vaginal mucosa and cultured cells were examined by quantitative real-time RT-PCR. The expressions of Gal-1, -2, and -3 of the vaginal mucosa were significantly greater in old birds than in young birds. Expression of these Gals in the vagina were decreased in the regressed oviduct of non-laying birds compared with laying birds. The expressions of Gal-1, -2, and -3 in the cultured vaginal cells were increased by stimulation with SE or LPS within 24 h. These results suggest that the mRNA expressions of Gal-1, -2 and -3 in the vagina of laying hens increased with age, whereas they decreased in the regressed oviduct during the non-laying phase. Also, synthesis of these antimicrobial peptides in the vagina may increase in response to SE and LPS to eliminate SE bacteria.     

Characterization of monoclonal antibodies directed against the canine distemper virus nucleocapsid protein

We have established four monoclonal antibodies (MAbs) against the nucleocapsid protein (NP) of canine distemper virus (CDV). A competitive binding assay has revealed that the MAbs are directed against two antigenic domains. An immunofluorescence assay using a series of deletion clones of the NP and an immunoprecipitation assay using the NP have revealed that two of the MAbs recognize the C-terminal region of the NP while the other two recognize the tertiary structure of the N-terminal domain. These MAbs reacted with all eight strains of CDV used in this study, but showed different reactivities against measles virus and rinderpest virus.     

Nephrocalcinosis formation by soy isoflavones in male rats

Isoflavones (IFs), found in the form of both aglycones and glucosides in soybean foods, induce weak estrogenic activities. Although IFs have a number of health benefits, it was previously reported that IFs cause nephrocalcinosis (NC) in the kidney of male Fischer 344 (F344) rats. The present study aims to elucidate the safety of IFs by focusing on IF-induced NC formation in rats. Fermented soybean extract (FSE) containing 420 mg/g isoflavone aglycones was orally administered to male F344 and Sprague-Dawley (SD) rats for 28 days. FSE induced NC formation in the kidney of F344 rats, but not in SD rats. However, absorption of IFs did not differ between F344 and SD rats. NC formation and its severity of FSE were histologically compared with those of soybean extract (SE) containing 518 mg/g isoflavone glucosides in F344 rats. There were no differences in the number of NC formations and the extent of calcium deposit between FSE and SE groups. To examine the dose effect of FSE on NC formation, doses of 20, 140, or 1000 mg/kg FSE were administered to F344 rats for 90 days. NC formation was observed in the 140 and 1000 mg/kg groups. These results indicated that a high dose of oral administration of IFs induced NC formation depending on the strain of rat.