Food-grade mulberry powder enriched with 1-deoxynojirimycin suppresses the elevation of postprandial blood glucose in humans

Mulberry 1-deoxynojirimycin (DNJ), a potent glucosidase inhibitor, has been hypothesized to be beneficial for the suppression of abnormally high blood glucose levels and thereby prevention of diabetes mellitus. However, DNJ contents in commercial mulberry products were as low as about 0.1% (100 mg/100 g of dry product), implying that the bioavailability of DNJ might not be expected. We carried out studies in two directions: (1) production of food-grade mulberry powder containing a maximally high DNJ content; (2) determination of the optimal dose of the DNJ-enriched powder for the suppression of the postprandial blood glucose through clinical trials. The following method was used: (1) DNJ concentrations in mulberry leaves from different cultivars, harvest seasons, and leaf locations were determined using hydrophilic interaction chromatography with evaporative light scattering detection. (2) Healthy volunteers received 0, 0.4, 0.8, and 1.2 g of DNJ-enriched powder (corresponding to 0, 6, 12, and 18 mg of DNJ, respectively), followed by 50 g of sucrose. Before and 30-180 min after the DNJ/sucrose administration, plasma glucose and insulin were determined. The following results were obtained: (1) Young mulberry leaves taken from the top part of the branches in summer contained the highest amount of DNJ. After optimization of the harvesting and drying processes for young mulberry leaves (Morus alba L. var. Shin ichinose), DNJ-enriched powder (1.5%) was produced. (2) A human study indicated that the single oral administration of 0.8 and 1.2 g of DNJ-enriched powder significantly suppressed the elevation of postprandial blood glucose and secretion of insulin, revealing the physiological impact of mulberry DNJ (effective dose and efficacy in humans). This study suggests that the newly developed DNJ-enriched powder can be used as a dietary supplement for preventing diabetes mellitus.     

Effects of the administration of growth hormone-releasing peptide-2 (GHRP-2) orally by gavage and in feed on growth hormone release in swine

The experiments were conducted to determine the effects of the administration of growth hormone-releasing peptide-2 (GHRP-2, also named KP102), both orally by gavage and in feed, on the release of growth hormone (GH) in swine and to investigate whether attenuation of the GH response occurs after short-term treatment with the peptide in feed. In the first experiment, saline or GHRP-2 at doses of 1, 4.5 and 9 mg/kg body weight (BW) was dissolved in 15 ml saline and administered orally as a bolus by gavage to cross-bred castrated male swine (n = 6). Orally administered GHRP-2 stimulated dose-related increases in peak concentrations of GH, with a return to basal by 120 min. After administering GHRP-2 orally, peak concentrations of GH and areas under the GH response curves (GH AUCs) for 180 min were higher (P < 0.05) than those in saline controls. In Experiment 2, GHRP-2 at doses of 0 (served as control), 1, 4.5 and 9 mg/kg BW was mixed in 150 g of feed and offered to cross-bred castrated male swine (n = 6) at 0900 hr and 1700 hr daily for a 3-d period. Administration of 1 mg/kg BW GHRP-2 to swine in feed failed to stimulate the release of GH, but GHRP-2 at doses of 4.5 and 9 mg/kg BW significantly (P < 0.05) increased plasma concentrations of GH after initial and final treatments at 0900 hr on Days 1 and 3 of treatment, respectively. Peak concentrations of GH and GH AUCs for 180 min after the initial and final treatments in the 4.5 and 9 mg/kg BW GHRP-2-treated swine were higher (P < 0.05) than those in controls. After 3 d of treatment with GHRP-2 in feed at doses of 4.5 and 9 mg/kg BW, GH responses to the peptide were maintained. The results of the present study indicate that the administration of GHRP-2 orally by gavage and in feed stimulates the release of GH in swine, and that the GH-releasing effect of the peptide does not become desensitized after short-term administration in feed.     

The effects of growth hormone-releasing peptide-2 (GHRP-2) on the release of growth hormone and growth performance in swine

The effects of GHRP-2 (also named KP102), a new growth hormone-releasing peptide, on the release of growth hormone (GH) and growth performance were examined in swine. The single intravenous (i. v.) injection of GHRP-2 at doses of 2, 10, 30 and 100 microg/kg body weight (BW) to cross-bred castrated male swine stimulated GH release in a dose-dependent manner, with a return to the baseline by 120 min. The peak GH concentrations and GH areas under the response curves (GH AUCs) for 180 min after the injections of GHRP-2 were higher (P < 0.05) than those after the injection of saline. The GH responses to repeated i.v. injections of GHRP-2 (30 microg/kg BW) at 2-h intervals for 6 h were decreased after each injection. The chronic subcutaneous (s.c.) administration of GHRP-2 (30 microg/kg BW) once daily for 30 days consistently stimulated GH release. The GH AUCs for 300 min after the injections on d 1, 10 and 30 of treatment in GHRP-2-treated swine were higher than those in saline-treated swine. However, chronic administration of GHRP-2 caused a partial attenuation of GH response between d 1 and 10 of treatment. The chronic s.c. administration of GHRP-2 also increased average daily gain for the entire treatment period by 22.35% (P < 0.05) and feed efficiency (feed/gain) by 20.64% (P < 0.01) over the saline control values, but did not significantly affect daily feed intake. These results indicate that GHRP-2 stimulates GH release and enhancing growth performance in swine.     

New multilocus genotypes of <Emphasis Type="Italic">Phytophthora infestans</Emphasis> in Japan

Twelve isolates of Japanese Phytophthora infestans, which differed from the major genotypes US-1, JP-1, JP-2, and JP-3, were analyzed for RG57 fingerprints, mtDNA haplotypes, two allozyme genotypes, and mating types. Genotypes JP-1.1, JP-2.1, JP-2.2, JP-3.1, and JP-4 were newly defined. JP-1.1 and JP-2.1 were isolated discontinuously from potato fields in several years, and JP-1.1 was found in Hokkaido and Kagoshima. These results show that some minor genotypes can overwinter and disperse from their original site.     

Burkholderia gladioli associated with symptoms of bacterial grain rot and leaf-sheath browning of rice plants

Rice plants with bacterial leaf-sheath browning and grain rot were observed in Fukuoka Prefecture in Japan during the autumn seasons of 1995 and 1996. Burkholderia spp. were consistently isolated from the infected leaf sheaths and grains. These isolates were pathogenic and induced symptoms of seedling rot, grain rot, and leaf-sheath browning in rice plants, as well as in some orchidaceous plants (cymbidium, dendrobium, and oncidium leaves), gladiolus leaves, and onion bulbs. On the basis of morphological, physiological and pathological tests, and species-specific polymerase chain reaction, the isolates were identified as belonging to either Burkholderia glumae or Burkholderia gladioli. B. gladioli, as well as B. glumae, attacked rice plants after artificial inoculation and reproduced the symptoms similar to those after natural infections. We confirmed that rice is an additional natural host of B. gladioli. It is clarified that bacterial grain rot of rice is caused not only by B. glumae but also by B. gladioli.     

Atomic-level observation of disclination dipoles in mechanically milled, nanocrystalline Fe

Plastic deformation of materials occurs by the motion of defects known as dislocations and disclinations. High-resolution transmission electron microscopy was used to directly reveal the individual dislocations that constitute partial disclination dipoles in nanocrystalline, body-centered cubic iron that had undergone severe plastic deformation by mechanical milling. The mechanisms by which the formation and migration of such partial disclination dipoles during deformation allow crystalline solids to fragment and rotate at the nanometer level are described. Such rearrangements are important basic phenomena that occur during material deformation, and hence, they may be critical in the formation of nanocrystalline metals by mechanical milling and other deformation processes.     

Evaporative light-scattering analysis of sulforaphane in broccoli samples: Quality of broccoli products regarding sulforaphane contents

Broccoli sulforaphane has received attention as a possible anticarcinogen. Sulforaphane analysis is difficult due to the lack of a chromophore for spectrometric detection. Hence, we developed a method for determining sulforaphane by using high-performance liquid chromatography (HPLC) coupled with an evaporative light-scattering detector (ELSD). Sulforaphane was extracted from acid-hydrolyzed broccoli samples, followed by solid-phase extraction and reversed-phase HPLC. Sulforaphane was detected by ELSD and concurrently identified by electrospray ionization time-of-flight mass spectrometry. The recovery of sulforaphane from broccoli samples was above 95%. The detection limit was 0.5 mug. The present method was sensitive enough to determine sulforaphane in mature broccoli, broccoli sprouts, and commercial broccoli products. Sulforaphane concentration in broccoli sprout (1153 mg/100 g dry weight) was about 10 times higher than that of mature broccoli (44-171 mg/100 g dry weight). Therefore, the broccoli sprout is recommended as a source of sulforaphane-rich products. In contrast, we found that sulforaphane could not be detected in most of broccoli products, suggesting present commercial broccoli products having low quality.