Femtomolar bradykinin-induced relaxation of isolated bovine coronary arteries, mediated by endothelium-derived nitric oxide

We reported previously that bradykinin induces endothelium-dependent relaxation at nanomolar (n M ) concentrations in isolated bovine coronary arteries with an intact endothelium. Recently we have found that in the presence of 10 μ m indomethacin, femtomolar (f M ) concentrations of bradykinin induce endothelium-dependent relaxation in some bovine coronary arteries (≈ 10% of the coronary arteries examined). The present study was designed to characterize the relaxation induced by f M bradykinin. Relaxation was completely abolished by repeated application of f M bradykinin, by 100 μ m N^ω- nitro- l - arginine methyl ester and by 10 μ m methylene blue. Relaxation induced by n M bradykinin was partly affected by these treatments. Relaxation induced by both concentrations of bradykinin was inhibited by a B₂-kinin receptor antagonist, [Thi^5,8, D-Phe⁷]-bradykinin, in a concentration-dependent manner, but not by a B₁-kinin receptor antagonist, des-Arg⁹, [Leu⁸]-bradykinin. In the presence of 10 μ m captopril, an angiotensin-converting enzyme (ACE) inhibitor, all coronary arteries examined in this experiment showed endothelium-dependent relaxation to f M bradykinin. These results show that some bovine coronary arteries relax in response to f M bradykinin, and this response is mediated predominantly by the release of nitric oxide via stimulation of endothelial B₂-kinin receptors. The relaxation may be dependent on ACE activity.     

Detection of a bovine group C rotavirus from adult cows with diarrhea and reduced milk production

Only two strains (Shintoku and porcine-like WD534tc) of group C rotavirus (GCR) from cattle have been reported to date. A GCR designated the Yamagata strain was the only pathogen detected in an outbreak of adult cow diarrhea accompanied by a decrease in milk production. The nucleotide sequences of the VP6 and VP7 genes from strain Yamagata were determined. Comparative sequence analysis showed that the sequence identities between strains Yamagata and Shintoku were markedly high in both VP6 gene (98.1%) and VP7 gene (93.5%), and that these strains belonged to the same clusters which were distinguished from GCRs from different host species in phylogenetic trees of these genes. These results suggested strongly that cattle species is one of the natural hosts of GCR infection, and that GCRs are a cause of adult cow diarrhea.     

Carotenoid Profile of Edible Japanese Seaweeds: An Improved HPLC Method for Separation of Major Carotenoids

An improved multi-step gradient reverse phase high performance liquid chromatography (HPLC) method to simultaneously separate major carotenoids from natural as well as food samples was developed. Quantitative profiling of carotenoid compounds was carried out on three edible brown seaweeds (Sargassum horneri, Cystoseira hakodatensis, and Undaria pinnatifida) and three red seaweeds (Gracilaria vermiculophylla, Grateloupia asiatica, and Grateloupia livida). Fucoxanthin (Fx) was detected in all the brown seaweeds with quantities (mg g^?1 dry weight [dwt]) ranging from 1.3 ± 0.3 in C. hakodatensis to 2.4 ± 0.1 in S. horneri. U. pinnatifida, commonly known as wakame, had a Fx content of 2.3 ± 0.1 mg g^?1 dwt. In the case of red seaweeds, zeaxanthin (Zx) was the major carotenoid, and G. vermiculophylla had the highest Zx content (80.2 μg g^?1 dwt) among the red seaweeds apart from small amounts of Fx (9.1 μg g^?1 dwt). Similarly, the other two species of red seaweeds, G. asiatica and G. livida, contained (μg g^?1 dwt) lutein (Lut), Fx, and Zx as the major carotenoids (G. asiatica: Lut 10.4, Fx 1.5, Zx 1.1; G. livida: Lut 9.3, Fx 3.5, Zx 1.0). The results suggest the usefulness of edible varieties (barring wakame) of seaweeds as dietary sources of carotenoids.     

Effects of a meal rich in 1,3-diacylglycerol on postprandial cardiovascular risk factors and the glucose-dependent insulinotropic polypeptide in subjects with high fasting triacylglycerol concentrations

It was previously reported that compared to triacylglycerol (TAG) oil, diacylglycerol (DAG) oil improves postprandial lipid response. However, the effects of DAG oil on postprandial hyperglycemia and incretin response have not yet been determined. In this study, the effects of DAG oil on both postprandial hyperlipidemia and hyperglycemia and the response to the glucose-dependent insulinotropic polypeptide (GIP) were studied. This randomized, double-blind, crossover study analyzed data for 41 individuals with high fasting triacylglycerol concentrations. The subjects ingested test meals (30.3 g of protein, 18.6 g of fat, and 50.1 g of carbohydrate) containing 10 g of DAG oil (DAG meal) or TAG oil (TAG meal) after fasting for at least 12 h. Blood samples were collected prior to and 0.5, 2, 3, 4, and 6 h after ingestion of the test meal. Postprandial TAG concentrations were significantly lower after the DAG meal compared with the TAG meal. Postprandial TAG, insulin, and GIP concentrations were significantly lower after the DAG meal compared with the TAG meal in 26 subjects with fasting serum TAG levels between 1.36 and 2.83 mmol/L. DAG-oil-based meals, as a replacement for TAG oil, may provide cardiovascular benefits in high-risk individuals by limiting lipid and insulin excursions.     

Accumulation mechanism of γ-aminobutyric acid in tomatoes (Solanum lycopersicum L.) under low O2 with and without CO2

The storage of ripe tomatoes in low-O(2) conditions with and without CO(2) promotes γ-aminobutyric acid (GABA) accumulation. The activities of glutamate decarboxylase (GAD) and α-ketoglutarate-dependent GABA transaminase (GABA-TK) were higher and lower, respectively, following storage under hypoxic (2.4 or 3.5% O(2)) or adjusted aerobic (11% O(2)) conditions compared to the activities in air for 7 days at 25 °C. GAD activity was consistent with the expression level of mRNA for GAD. The GABA concentration in tomatoes stored under hypoxic conditions and adjusted aerobic conditions was 60-90% higher than that when they are stored in air on the same day. These results demonstrate that upregulation of GAD activity and downregulation of GABA-TK activity cause GABA accumulation in tomatoes stored under low-O(2) conditions. Meanwhile, the effect of CO(2) on GABA accumulation is probably minimal.     

Stimulation of gamma-aminobutyric acid production in vine-ripe tomato (Lycopersicon esculentum Mill.) fruits under modified atmospheres

Stimulation of gamma-aminobutyric acid (GABA) production under low O2 and high CO2 conditions (adjusted aerobic atmosphere) under which ethanol fermentation could be avoided was studied. Vine-ripe tomato fruits were stored under hypoxia conditions and adjusted aerobic atmospheres as well as in the air at 15 degrees C for 13 days and at 30 degrees C for 6 days. At 30 degrees C tomato fruit GABA concentration under the adjusted aerobic atmosphere (O2 11%, CO2 9%) was significantly higher by 48% than that in air after 6 days from the start of storage. Increased accumulation of alanine under the adjusted aerobic atmosphere supports the observation that this atmosphere stimulates GABA production. The results demonstrate that the concentration of GABA as a beneficial substance for antihypertensive effects and so on can be increased by storing tomato fruits under adjusted aerobic atmospheres for the first time.     

Changes of multi-drug resistance pattern in Salmonella enterica subspecies enterica serovar typhimurium isolates from food-producing animals in Japan

A total of 153 isolates of Salmonella Typhimurium derived from food-producing animals in Japan between 2002 and 2005 were investigated for antimicrobial resistance and phage types related to definitive phage type 104 (DT104). The predominant resistance type was resistance to ampicillin, dihydrostreptomycin, kanamycin, and oxytetracycline in bovine (45.2%, 48/104) and resistance to dihydrostreptomycin and oxytetracycline in porcine isolates (58.7%, 27/48). DT104-related phage type was found in 32 of 104 bovine isolates, two of 48 porcine isolates, and one of eight isolates from poultry, showing that the proportion of the phage type in S. Typhimurium isolates from cattle and pigs significantly (P<0.01) decreased from 71.9% and 31.4% in 1999-2001 to 30.8% and 4.1% in 2002-2005, respectively.     

3维图像处理系统在稻米品质检测中的应用研究

利用微切片3维图像处理系统对稻米的品质特性进行了探索性的研究。结果表明，借助于3维可视化技术，可以对稻谷的外观品质、营养品质及蒸煮品质等进行更为直观且客观的观察与测定。尤其是在营养成分分布密度的评价、心白米内部组织的分析、蒸煮过程中组织结构变化的观测等方面，取得了传统研究方法难以获得的结果。利用该系统对垩白度的定量化测定，为食品的定量形态学研究开辟了一条新的研究途径。