Transglycosylation of naringin by Bacillus stearothermophilusMaltogenic amylase to give glycosylated naringin.

Naringin, a bitter compound in citrus fruits, was transglycosylated by Bacillus stearothermophilus maltogenic amylase reaction with maltotriose to give a series of mono-, di-, and triglycosylnaringins. Glycosylation products of naringin were observed by TLC and HPLC. The major glycosylation product was purified by using a Sephadex LH-20 column. The sturcture was determined by using MALDI-TOF MS, methylation analysis, and (1)H and (13)C NMR. The major transglycosylation product was maltosylnaringin, in which the maltose unit was attached by an alpha-1-->6 glycosidic linkage to the D-glucose moiety of naringin. This product was 250 times more soluble in water and 10 times less bitter than naringin.     

Multiplication of isolate R-5 of <Emphasis Type="Italic">Streptomyces galbus</Emphasis> on rhododendron leaves and its production of cell wall-degrading enzymes

 An endophytic actinomycete, isolate R-5 of Streptomyces galbus Frommer, that has promising potential as a biocontrol agent was originally isolated from field-grown rhododendron. In this study, the mode of entry of R-5 into leaves of tissue-cultured seedlings of rhododendron was investigated in connection with its production of cell wall-degrading enzymes. Light and scanning electron microscopy (SEM) revealed that R-5 grew on leaf surfaces and entered leaf tissues via stomata and that the internal mycelia grew out of stomata after colonization in host tissues. Micromanipulation at the SEM level demonstrated a prominent depression in the host surface at the interfaces with the mycelia, suggesting that such a depression could be caused by degradation of cell wall components by hydrolytic enzymes secreted from R-5 mycelia. In subsequent plate assays, R-5 produced cellulase, pectinase, xylanase, and nonspecific esterase when cultured in liquid medium. Moreover, R-5 multiplied in mineral medium containing cellulose, pectin, or xylan as a single carbon source. Thus, R-5 mycelia could degrade host cell walls at contact sites and probably utilize the degradation products as carbon sources. Received: May 16, 2002 / Accepted: July 9, 2002     

The effect of 7.2% hypertonic saline solution with 6% dextran 70 on cardiac contractility as observed by an echocardiography in normovolemic and anesthetized dogs

We studied the effect of a small volume of 7.2% hypertonic saline solution (HSS) or HSS with 6% dextran 70 (HSD) on hemodynamic status, especially on cardiac contractility, in anesthetized dogs using the left ventricular end-systolic volume index (ESVI) and ejection fraction (EF), which can be obtained in noninvasive echocardiography. In the present study, the mean values of ESVI were unaffected by HSS and HSD infusion, whereas the left ventricular end-diastolic volume index (EDVI) was markedly and significant increased. As a result of the changes in EDVI but not in ESVI, EF increased transiently and significantly in the HSS and HSD group, whereas no such significant change was observed in the dogs that received isotonic saline solution. In addition, as a result of the increases in cardiac index but not arterial pressure, system vascular resistances (SVR) decreased transiently and significantly in the HSS and HSD groups, whereas no such significant change was observed in the ISS group. Therefore, the positive inotropic effects of HSS and HSD may be attributable to the increase in left ventricular preload and decreases in SVR rather than direct changes in myocardial contractility.     

Detection of SNPs in fish DNA: application of the fluorogenic ribonuclease protection (FRIP) assay for the authentication of food contents

The fluorogenic ribonuclease protection (FRIP) assay was used to detect single nucleotide polymorphisms (SNPs) in commercially produced fish products. By using fluorescence resonance energy transfer (FRET) between fluorophore and quencher labeled probes, the species-specific cleavage of sample RNA was detected by measuring the fluorescence intensity during the FRIP assay. We were able to discriminate raw and thermally processed eel and tuna species using the FRIP-based SNP detection method. Furthermore, the intensity of fluorescence was correlated with the mutant/wild-type ratio. These results suggest that the FRIP assay is a useful method for the in situ confirmation of labels of fishery foods during food production.     

Haplotype diversity and molecular evolution of the rice <Emphasis Type="Italic">Pikm</Emphasis> locus for blast resistance

Pikm-specific rice blast resistance is conferred by a combination of two genes that have a nucleotide-binding site and a leucine-rich repeat (LRR), Pikm1-TS and Pikm2-TS. To study the evolution of these genes, we investigated the allele diversity of their LRR regions in 16 elite rice cultivars and 35 landraces. Both phylogenetic trees were characterized by a deep bifurcation that separated two major clades of alleles. A high level of polymorphism was detected exclusively between these clades and not within each clade. This two-clade structure commonly observed for the two genes suggests that these genes have evolved together through bidirectional differentiation.     

Effect of isotonic and hypotonic lactated ringer's solutions with dextrose intravenously administered to dehydrated heifers

To determine the effects of rapid infusion of essential fluids in a volume of hypotonic lactated Ringer's solution, the central venous pressure (CVP) and acid-base equilibrium were investigated in to mildly dehydrated heifers. Mild dehydration was induced in 9 Holstein heifers by withholding food and water until 7.0+/-5.7% of plasma volume had been lost. The heifers were randomly assigned to the ILG (lactated Ringer's + 5% dextrose), HLG (1/2 lactated Ringer's + 2.2% dextrose) or HRG (1/2 Ringer's + 2.5% dextrose) groups with 3 heifers in each group. Heifers received 30 ml/kg of one of the fluids, at a flow rate of 20 ml/kg/hr. The rapid intravenous (IV) infusions of HLG and HRG used in this study were found to be safe and effective in increasing plasma volume without increasing CVP, even though the infusion was given to the jugular vein at a dosage of 30 ml/kg. However, ILG infusion induced progressive increases in CVP, reaching 9.0+/-2.0 mmHg. No clinical signs, such as moist rales on auscultation, moist cough, jugular vein congestion, ophthalmoptosis, salivation or arrhythmia, were observed throughout the fluid infusion. The relative changes in base excess (rBE) for the ILG and HRG groups were significantly decreased until the end of fluid infusion. As for the HLG group, rBE slightly decreased until the end of the fluid infusion. Then the values significantly increased and exceeded the pre-infusion value at the end of the experiment. While IV infusion of HLG inhibited acidification caused by dilution, HRG infusion induced diluted acidification. It is suggested that HLG infusion should be examined as a treatment for cattle with dehydration and moderate metabolic acidosis, since rapid infusion of HLG may be more beneficial for rehydrating cattle with metabolic acidosis than current treatment.     

Determination of a novel bitter amino acid, pulcherrimine, in the gonad of the green sea urchin Hemicentrotus pulcherrimus

SUMMARY: A novel bitter amino acid, pulcherrimine was analyzed by reverse-phase high-performance liquid chromatography using a linear gradient elution consisting of methanol/aqueous/acetic acid and methanol/acetic acid mixture, after being labeled with dimethylaminoazobenzenesulfonyl chloride (Dabs-Cl). Linearity of the calibration curve for pulcherrimine was high ( r = 0.994) in the tested range from 0 to 4 μg/mL. By this method, the pulcherrimine content in the ovary and testis of the green sea urchin Hemicentrotus pulcherrimus , collected in the sea off Iwaki in November 1998, was analyzed. The mean pulcherrimine content in the ovary was 1.37 mg/100 g. In contrast, no pulcherrimine was detected in all testes examined. Correlation between the bitterness and the pulcherrimine content was statistically significant. These results strongly support that pulcherrimine is a bitter principle in the green sea urchin ovaries.     

Genetic diversity of African wild rice (Oryza longistaminata Chev. et Roehr) at the edge of its distribution

Ethiopia is at the edge of the distribution for African wild rice, Oryza longistaminata. Here, chloroplast (cp) and simple sequence repeat (SSR) markers were applied to wild rice accessions in Ethiopia to evaluate how they differ from control O. longistaminata, O. barthii and O. glaberrima accessions which originated from African countries. Based on the cp genomes of African wild rice species, maternally inherited cpINDEL markers were developed. The cp indels helped to elucidate 20 plastid types. African cultivated rice shared a particular plastid type with one of annual O. barthii. Parts of northern wild rice in Ethiopia shared Type 6 with control O. longistaminata. The north group shared another type with parts of the south group. The 16 SSR markers amplified a total of 155 alleles in 215 rice accessions, with mean allelic richness of 9.688 per locus, observed heterozygosity of 0.241, expected heterozygosity of 0.724, polymorphic information content of 0.700, and a significant genetic differentiation of 0.215. Both cpINDEL and nuclear markers analyses suggested that wild rice in Ethiopia belongs to O. longistaminata. However, they carry both a unique plastid type and different population structure from control O. longistaminata collected from other areas in Africa. We concluded that the edge of its distribution maintains unique variation. These populations are regarded as valuable genetic resources for future rice breeding.

     

Photosynthetic traits and growth of Quercus mongolica var. crispula sprouts attacked by powdery mildew under free-air CO2 enrichment

To predict the performance of coppice forests with Japanese oak (Quercus mongolica var. crispula) in future changing environment, we studied the growth, photosynthesis, and powdery mildew (Erysiphe alphitoides) infection of sprouts of Japanese oak under free-air CO₂ enrichment. Elevated CO₂ reduced powdery mildew infection in both leaves of the shoot emerged in spring (1st flush) and the lammas and proleptic shoots (2nd flush) of sprouts. We observed significant increase in the net photosynthetic rate at growth CO₂ concentration (i.e., 370 and 500 μmol mol^?1 for ambient and elevated CO₂ treatments, respectively) in both 1st and 2nd flush leaves of sprouts grown under elevated CO₂. On the other hand, no significant increase in net photosynthetic rate under elevated CO₂ was found before cutting. The photosynthetic activity of 2nd flush leaves in the sprouts under ambient condition was greatly reduced by severe infection to powdery mildew. Growth of sprouts was enhanced in the elevated CO₂ condition. We conclude the growth enhancement in Japanese oak sprouts under elevated CO₂ in the present study was achieved not only by physiological response (i.e., photosynthetic stimulation) but also by disease interaction.