Identification of a peptide in enzymatic hydrolyzate of cheese that inhibits ovalbumin permeation in Caco-2 cells

Because the first step in the triggering of food allergy is the permeation of the allergen through the intestine, enhancement of the intestinal barrier function is thought to be effective for preventing food allergy. In this study, a peptide that inhibits ovalbumin (OVA) permeation in an in vitro Caco-2 cell model was isolated from enzymatic hydrolyzate of cheese (EHC). Amino acid sequence analysis identified the active peptide as GPIVLNPWDQ, a sequence identical to amino acids 102-111 of alphas2-casein. The decapeptide significantly inhibited OVA permeation at a concentration of 10(-6) M. In addition, it was found that a pentapeptide half, NPWDQ, is essential for the inhibitory activity because NPWDQ but not GPIVL had nearly the same inhibitory activity as GPIVLNPWDQ. The possibility exists that EHC and/or peptides possessing the NPWDQ sequence can be practically applied to the prevention of food allergy.     

Absorption,translocation, and assimilation of foliar-applied urea compared with nitrate and ammonium in tomato plants

To evaluate the use of foliar application of N fertilizer and the occurrence of leaf injury in tomato plants (Lycopersicon esculentum Mill., cv. Momotaro), the effects of the form and concentration of N and solution pH on the leaf injury were studied in the first experiment (Expt. 1). The effects of solution pH and leaf surface on the absorption, translocation, and assimilation of urea were compared with those of nitrate and ammonium in the second experiment (Expt. 2). In Expt. 1, no leaf injury was observed regardless of N sources applied at the N concentration of 1.0 g L^-1. Compared with nitrate or ammonium, the index of leaf injury was the lowest in the leaf to which urea had been applied (hereafter referred to as “urea-applied leaf”), when the N level increased from 2.0 to 10.0 g L^-1. Leaf injury was not affected by the solution pH in the case of urea, but it increased in the case of ammonium and decreased when nitrate was applied with increasing solution pH. In Expt. 2, the absorption of nitrate and ammonium by a leaf within 4 d was 34% and 74% of that of urea, respectively. N absorption at the lower leaf surface was much greater than that at the upper leaf surface for each N source. No apparent effect of solution pH on the absorption of urea was detected. With increasing solution pH, however, the absorption of nitrate decreased. The absorption of ammonium was the greatest at solution pH 7.5. Total-¹⁵N translocation from applied leaf to other plant parts within 4 d was the largest in the urea-applied plants. Effects of solution pH and leaf surface on ¹⁵N distribution were not appreciable. ¹⁵N assimilation was the quickest in the urea-applied plants. Two days after application, ¹⁵N assimilation in the whole plant was up to 76.9% in the urea-applied plants, but only 33.7% and 43.0% in the nitrate- and ammonium-applied plants, respectively. Urea was an appropriate foliar N source due to the low ability to injure foliage because of the rapid absorption and translocation, fast assimilation, and the wide and suitable range of solution pH. Foliar application of N to the lower leaf surface was recommended.     

EDEM as an acceptor of terminally misfolded glycoproteins released from calnexin

Terminally misfolded proteins in the endoplasmic reticulum (ER) are retrotranslocated to the cytoplasm and degraded by proteasomes through a mechanism known as ER-associated degradation (ERAD). EDEM, a postulated Man8B-binding protein, accelerates the degradation of misfolded proteins in the ER. Here, EDEM was shown to interact with calnexin, but not with calreticulin, through its transmembrane region. Both binding of substrates to calnexin and their release from calnexin were required for ERAD to occur. Overexpression of EDEM accelerated ERAD by promoting the release of terminally misfolded proteins from calnexin. Thus, EDEM appeared to function in the ERAD pathway by accepting substrates from calnexin.     

Fisheries resource management of the daggertooth pike conger,Muraenesox cinereus,using existing limited datasets in the western Seto Inland Sea,Japan

The daggertooth pike conger, Muraenesox cinereus (Forsskål), has become an important fish resource in the western Seto Inland Sea, Japan, since the 1990s. However, introducing sustainable fisheries resource management for this species is difficult in this region because stock assessments have not been performed, and official fisheries statistics for this stock were discontinued after 2007. This study used existing limited data sets to compile the first report for fisheries resource management for this M. cinereus stock. Yield‐per‐recruit analyses showed that increasing fishing pressure above current levels would provide only a minimal increase in expected catch levels. Hence, the current harvest level is considered to represent the upper limit of fishing pressure. Age composition in a given year could potentially be used to forecast landing abundance for the following 2 years. This study provides a basis for establishing effective fisheries resource management strategies for M. cinereus.     

Orbital influence on Earth's magnetic field: 100,000-year periodicity in inclination

A continuous record of the inclination and intensity of Earth's magnetic field, during the past 2.25 million years, was obtained from a marine sediment core of 42 meters in length. This record reveals the presence of 100,000-year periodicity in inclination and intensity, which suggests that the magnetic field is modulated by orbital eccentricity. The correlation between inclination and intensity shifted from antiphase to in-phase, corresponding to a magnetic polarity change from reversed to normal. To explain the observation, we propose a model in which the strength of the geocentric axial dipole field varies with 100,000-year periodicity, whereas persistent nondipole components do not.     

Ascophyllan Purified from Ascophyllum nodosum Induces Th1 and Tc1 Immune Responses by Promoting Dendritic Cell Maturation

Marine-derived sulfated polysaccharides have been shown to possess certain anti-virus, anti-tumor, anti-inflammatory and anti-coagulant activities. However, the in vivo immunomodulatory effects of marine-derived pure compounds have been less well characterized. In this study, we investigated the effect of ascophyllan, a sulfated polysaccharide purified from Ascophyllum nodosum, on the maturation of mouse dendritic cells (DCs) in vitro and in vivo. Ascophyllan induced up-regulation of co-stimulatory molecules and production of pro-inflammatory cytokines in bone marrow-derived DCs (BMDCs). Moreover, in vivo administration of ascophyllan promotes up-regulation of CD40, CD80, CD86, MHC class I and MHC class II and production of IL-6, IL-12 and TNF-α in spleen cDCs. Interestingly, ascophyllan induced a higher degree of co-stimulatory molecule up-regulation and pro-inflammatory cytokine production than fucoidan, a marine-derived polysaccharide with well-defined effect for promoting DC maturation. Ascophyllan also promoted the generation of IFN-γ-producing Th1 and Tc1 cells in the presence of DCs in an IL-12-dependent manner. Finally, myeloid differentiation primary response 88 (MyD88) signaling pathway was essential for DC maturation induced by ascophyllan. Taken together, these results demonstrate that ascophyllan induces DC maturation, and consequently enhances Th1 and Tc1 responses in vivo. This knowledge could facilitate the development of novel therapeutic strategies to combat infectious diseases and cancer.     

Induction of Apoptotic Cell Death in Human Leukemia U937 Cells by C18 Hydroxy Unsaturated Fatty Acid Isolated from Red Alga Tricleocarpa jejuensis

Our previous studies have found that (±)-(E)-12-hydroxyoctadec-10-enoic acid (HOEA) isolated from the red alga Tricleocarpa jejuensis showed cytotoxic effects on various living organisms including harmful microalgae, Gram-positive bacteria, and mammalian tumor cells. Since natural products with apoptosis-inducing ability can be promising anti-cancer agents, in this study, we investigated the cytotoxic mechanism of HOEA on U937 cells focusing on apoptosis induction. HOEA showed much stronger cytotoxic and cytolytic effects on U937 cells than elaidic acid, which has similar structure but no 12-hydroxy group, suggesting that hydroxy group is important for the cytotoxicity of HOEA. HOEA induced apoptotic nuclear morphological changes, DNA fragmentation, and decrease in mitochondrial membrane potential. Furthermore, time-dependent increase in annexin V+/PI+ cell population in HOEA-treated U937 cells was detected. Among the apoptosis-related reagents, caspase-family inhibitor almost completely inhibited HOEA-induced DNA fragmentation. In the analyses using specific caspase-substrates, extremely high cleavage activity toward caspase-3/7/8 substrate was observed in HOEA-treated U937 cells, and weak activities of caspase-1 and -3 were detected. Analyses using specific caspase inhibitors suggested that caspase-3 and caspase-8 might be predominantly responsible for the cleavage activity. Activation of these caspases were also confirmed by western blotting in which significant levels of cleaved forms of caspase 3, caspase 8, and PARP were detected in HOEA-treated U937 cells. Our results suggest that HOEA is capable of inducing apoptosis in U937 cells in which caspase-3 and caspase-8 might play important roles. Since the cytotoxic effect of HOEA is not strictly specific to tumor cells, development of appropriate drug delivery system for selective tumor targeting is necessary for the clinical applications to reduce the possible side effects.     

Effects of melophlins on colony formation of Chinese hamster V79 cells and IL-8 production in PMA-stimulated HL-60 cells

We have recently isolated four new melophlins P (1), Q (2), R (3), and S (4) together with seven known melophlins A (5), D (6), E (7), G (8), H (9), I (10), and O (11) from two marine sponges of the genus Melophlus collected in Palau. In this study, the influence of these compounds on the colony formation of Chinese hamster V79 cells and the production of IL-8 in PMA-stimulated HL-60 cells were examined. These 11 compounds did not show any effect on IL-8 production. The EC₅₀ values of compounds 2, 3, 4, 5, 7, 9, 10, and 11 against V79 cells were 44.0, 13.3, 16.7, 27.2, 19.8, 8.5, 23.1, and 9.6 μM, respectively. The linear-chain-type compounds (1, 6, and 8) were not active against V79 cells at 50 μM. Although the growth inhibitory activity of these melophlins was not remarkable, some structure-activity relationships of these compounds against V79 and murine leukemia L1210 cells were observed.     

Isolation of Araguspongine M,a New Stereoisomer of an Araguspongine/Xestospongin alkaloid,and Dopamine from the Marine Sponge Neopetrosia exigua Collected in Palau

A new stereoisomer of an araguspongine/xestospongin alkaloid, named araguspongine M (1), has been isolated together with 12 known compounds, araguspongines B (2) and D (3), dopamine, three galactosyl diacylglycerols, 24-methyl cholesterol, 5,6-dihydrocholesterol, β-sitosterol, and three 5α,8α-epidioxy sterols (11–13), from the marine sponge Neopetrosia exigua (formerly Xestospongia exigua) collected in Palau. The structure of 1 was assigned on the basis of its spectral data analysis. This is the first report on the isolation of dopamine from a marine sponge. This compound may be produced by an endosymbiotic Synechococcus-like cyanobacterium. Compounds 1–3 and 11–13 showed cytotoxicity against HL-60 at IC₅₀’s of 5.5, 5.5, 5.9, 22.4, 9.5, and 9.6 μM, respectively. The possible biosynthesis origin of the isolated metabolites is discussed.     

Characteristics of developmental changes in the kinetics of glucose and urea in Japanese Black calves: comparison with Holstein calves

The current study was conducted to clarify the characteristics of glucose and urea kinetics in male Japanese Black calves, using a glucose and urea dilution method with stable isotopes, at preweaning (3 wk of age) and postweaning (13 and 26 wk of age) stages, in comparison with the kinetics of glucose and urea in male Holstein calves. Six Japanese Black and 6 Holstein calves were arranged in a 2 (breed) x 3 (stage) factorial block design. These 12 suckling calves were fed only whole milk, offered concentrate and or chardgrass hay after 3 wk of age, and weaned at 6 wk of age. Under steady-state conditions, glucose challenges (1.0 mg/kg of BW; [U-13C]d-glucose) and urea challenges (both 2.2 mg/kg of BW; [13C]urea and [15N2]urea) were performed at the 3 stages examined. There were no significant differences in plasma glucose concentrations between Japanese Black and Holstein calves at any stage, but the glucose concentrations at 3 wk of age were greater (P <0.05) than those at 13 wk of age in both breeds. The glucose pool size in Japanese Black calves was smaller (P <0.05) than that in Holstein calves at all stages. Within each breed, there were no significant differences between the glucose pool sizes at 3 and 13 wk of age, but the glucose pool size was larger (P <0.05) at 26 wk of age. Moreover, Japanese Black calves had greater glucose irreversible loss rates (P <0.01) than Holstein calves at 3 wk of age, and the glucose irreversible loss rates were less (P <0.05) on and after 13 wk of age in both breeds. Japanese Black calves had greater plasma urea N concentrations (P <0.05) than Holstein calves at all stages, and in both breeds, the urea N concentrations increased (P <0.05) with age. The urea pool size was smaller (P <0.01) in Japanese Black calves than in Holstein calves at all stages, and in both breeds, the urea pool size increased (P <0.05) with age. In comparison with Holstein calves, Japanese Black calves had greater urea irreversible loss rates (P <0.05) on and after 13 wk of age and greater urea recycling rates (P <0.05) at 26 wk of age. In addition, in both breeds, urea irreversible loss rates and urea recycling rates increased (P <0.05) with age. We conclude that Japanese Black calves have partially different glucose and urea kinetics from Holstein calves and that the kinetics of these metabolites in both Japanese Black and Holstein calves are strongly influenced by weaning.