Enzyme activity changes in relation to internal browning of Raphanus roots sown early and late     

Nobuyuki Fukuoka 《The Journal of Horticultural Science and Biotechnology》2013,88(4):456-460

Summary

Early sown radish seedlings were subjected to heat stress from the middle to late growth stage. Roots exhibiting internal browning (IB) were more prevalent in the susceptible cultivars whose seeds were sown early in the summer compared with those which were sown late. However, IB occurrence in the resistant ones was not nearly so marked regardless of the sowing date. In the IB susceptible cultivars, higher levels of L-phenylalanine ammonia-lyase (PAL) and polyphenol oxidase (PPO) activities were detected in roots from the early sown plot (ESP), but these enyzme inductions did not occur to a significant extent in the resistant ones. Roots suffering internal browning were also detected to have pronounced increases in ascorbate peroxidase (APX) activity, but decreases in both dehydroascorbate reductase (DHAR) and glutathione reductase (GHAR) activities. These observations strongly suggest that a decline in H₂O₂ decomposing capacity of the ascorbate-glutathione cycle by heat stress is responsible for the activation of H₂O₂ detoxyifying pathway derived from PPO.  相似文献   

Mass production of rubusoside using a novel stevioside-specific β-glucosidase from Aspergillus aculeatus     

Ko JA  Kim YM  Ryu YB  Jeong HJ  Park TS  Park SJ  Wee YJ  Kim JS  Kim D  Lee WS 《Journal of agricultural and food chemistry》2012,60(24):6210-6216

Rubusoside (R) is a natural sweetener and a solubilizing agent with antiangiogenic and antiallergic properties. However, currently, its production is quite expensive, and therefore, we have investigated nine commercially available glycosidases to optimize an economically viable R-production method. A stevioside (ST)-specific β-glucosidase (SSGase) was selected and purified 7-fold from Aspergillus aculeatus Viscozyme L by a two-step column chromatography procedure. The 79 kDa protein was stable from pH 3.0 to pH 7.0 at 50-60 °C. Hydrolysis of ST by SSGase produced R and steviol monoglucosyl ester as determined by (1)H and (13)C nuclear magnetic resonance (NMR). Importantly, SSGase showed higher activity toward ST than other β-linked glucobioses. The optimal conditions for R production were 280 mM ST and 16.6 μL of SSGase at pH 5.1 and 63 °C. This is the first discussion detailing the production of R by enzymatic hydrolysis of ST and is useful for the food additive and pharmaceutical industries.  相似文献   

Influenza virus neuraminidase inhibitory activity of phlorotannins from the edible brown alga Ecklonia cava     

Ryu YB  Jeong HJ  Yoon SY  Park JY  Kim YM  Park SJ  Rho MC  Kim SJ  Lee WS 《Journal of agricultural and food chemistry》2011,59(12):6467-6473

Influenza A virus infections continue to pose a major threat to humans and several animal species. Neuraminidase (NA) is one of the most promising targets for the development of drugs against influenza viruses because of its critical role in the viral life cycle. During the course of a search for NA inhibitors from edible natural sources, we found that the ethyl acetate layer of ethanol extracts of Ecklonia cava showed extremely high NA-inhibitory activity (72.1% inhibition at 30 μg/mL). Bioactivity-guided fractionation of the ethyl acetate layer yielded five phlorotannins, identified as phloroglucinol (1), eckol (2), 7-phloroeckol (3), phlorofucofuroeckol (4), and dieckol (5). The inhibitory activities of these compounds (1-5) against NAs from group-1 (A/Bervig_Mission/1/18 [H1N1], A/PR/8/34 [H1N1]) and group-2 (A/Hong Kong/8/68 [H3N2], A/Chicken/Korea/MS96/96 [H9N2]) influenza A were evaluated to determine potencies and kinetic behavior. Analyses using various in vitro influenza A virus NA assays showed that all five phlorotannin derivatives were selective NA inhibitors. Of the phlorotannins, phlorofucofuroeckol (4) exhibited the most potent inhibitory activities toward group-1 NAs (IC?? values, 4.5 and 14.7 μM), whereas dieckol (5) potently inhibited group-2 NAs. Kinetic analyses indicated that compounds 1-5 were all noncompetitive. Notably, these noncompetitive inhibitors synergized with oseltamivir to enhance the NA-inhibitory effects of oseltamivir.  相似文献   

Tracking the structural and functional development of a perennial pepperweed (Lepidium latifolium L.) infestation using a multi-year archive of webcam imagery and eddy covariance measurements     

O. Sonnentag  M. Detto  R. Vargas  Y. Ryu  B.R.K. Runkle  M. Kelly  D.D. Baldocchi 《Agricultural and Forest Meteorology》2011,151(7):916-926

The continued spread of invasive weeds is threatening ecosystem health throughout North America. Understanding the relationships between invasive weeds’ key phenological phases and structural and/or functional canopy development is an essential step for making informed decisions regarding their management. We analyzed a three-year image archive obtained from an inexpensive webcam overlooking a perennial pepperweed (Lepidium latifolium L.) infestation in California to explore the ability of red (R)-green (G)-blue (B) color space information to track the structural and functional development of the pepperweed. We characterized structural and functional canopy development through surface roughness length (z_0m; a proxy for canopy height and leaf area index) and canopy photosynthesis (F_A), respectively, both of which we derived from eddy covariance measurements. Here we demonstrate the use of cross-correlation functions to determine the temporal lags between chromatic coordinates and two color indices, all calculated from RGB brightness levels, with z_0m and F_A. We found that these color metrics fail to represent the structural and/or functional state of the canopy. In contrast, relative luminance (CIE Y) appears to be a better indicator for z_0m and especially for F_A. We calculated CIE Y from pepperweed RGB brightness levels in relation to hypothetical horizontal reference RGB brightness levels. We obtained the latter by applying the ratio between horizontally measured and hypothetical incoming solar radiation on a vertical surface to RGB brightness levels of a vertically oriented reference of invariant light-grey color. We conclude that webcam image archives may provide an inexpensive tool for making informed decisions regarding the timing but not for assessing the effectiveness of invasive plant control measures such as mowing.  相似文献   

Effects of different application timings of methane fermentation digested liquid to paddy plots on soil nitrogen and rice yield     

Satoko Watanabe  Kimihito Nakamura  Chan Seok Ryu  Michihisa Iida  Shigeto Kawashima 《Soil Science and Plant Nutrition》2013,59(2):224-237

Treatment of animal and food wastes using a methane fermentation technique is drawing considerable public attention as a suitable option for the utilization of biomass resources. The application of a fermentation byproduct (methane fermentation digested liquid) as an agricultural fertilizer has been investigated. Determining the appropriate timing required for applying digested liquid on a rice (Oryza sativa L.) paddy plot is important. The concentrations of soil nitrogen (N) components and rice yield should be considered because digested liquid contains both inorganic and organic N. This study compares the N transformation and the rice yield and growth at different application times over a period of 3 y. The effects of the timing of basal application on soil N were different and the timing that maximized the rice yield was different in each year. Days before ponding (DBP) affected soil N before mid-summer drainage, and rice growth rates at the panicle formation stage and the ear emergence stage. The effects of DBP disappeared before harvest. The results indicated that sufficient potentially mineralizable N existed regardless of DBP, and the effect of DBP lessened after the mid-summer drainage, which coincides with the period when N uptake is most active.  相似文献   

Physiological and Mineralogical Properties of Arsenic-Induced Chlorosis in Barley Seedlings Grown Hydroponically     

Molla Rahman Shaibur  Nobuyuki Kitajima  Reiko Sugawara  Toshihito Kondo  S. M. Imamul Huq  Shigenao Kawai 《Journal of plant nutrition》2013,36(2):333-353

The experiment was carried out to investigate the effects of arsenic (As) on the physiological and mineralogical properties of barley (Hordeum vulgare L. cv. ‘Minorimugi’). The plants were grown in nutrient solution treated with 0, 6.7, 33.5, and 67 μ M As (0, 0.5, 2.5, and 5 ppm As, respectively) in the phytotron. Dry matter yield of shoots and roots decreased significantly with the As treatments, indicating that barley plants are As-sensitive and As-toxicity depends on the As concentration in the rooting medium. Necrosis in older leaves and chlorosis symptoms (whitish color) in the fully developed young leaves were observed at the 33.5 and 67 μ M As treatments. Arsenic concentration, accumulation, and translocation increased with the increase of As concentration in the rooting medium. Arsenic was mostly concentrated in roots and a little amount was moved to shoots, indicating that As was not easily translocated to shoots of barley seedlings. Concentrations and accumulations of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), manganese (Mn), zinc (Zn), and copper (Cu) decreased significantly in shoots for 33.5 and 67 μ M As treatments as compared to the 0 μ M As treatment. Concentrations of P, K, Ca, Mg, Mn, and Cu decreased in roots, but Zn concentration increased in roots at 67 μ M As treatment. Accumulations of P, K, Ca, Mg, Mn, Zn, and Cu in roots also decreased significantly at 67 μ M As treatment. Accumulation of P and the cations showed negative relationship with As. Concentration of Fe decreased in shoots at 33.5 and 67 μ M As treatments where chlorosis was induced in the young leaf but increased in roots at 33.5 and 67 μ M As treatments. It was suggested that As might induce iron (Fe)-chlorosis in the plants. Among the micronutrients, Fe translocation was more affected than others by As. Phytosiderophore (PS) accumulation in roots, which is a symptom of Fe-deficiency in grasses, did not change significantly between 0 and 33.5 μ M As treatments; indicating that As-induced chlorosis did not enhance PS accumulation in roots and decreased due to As-toxicity at 67 μ M As treatment.  相似文献   

Changes in proline-14C metabolism in barley seedlings germinating at low temperature     

Nobuyuki Shiomi  Shiro Hori 《Soil Science and Plant Nutrition》2013,59(1):121-129

Changes in the metabolic pattern of proline-¹⁴C were examined in barley seedlings germinated at the low temperature of 2°C (LT) and compared with those germinated at 25°C (HT). In the LT shoots. proline-¹⁴C incorporation was higher in the cationic fraction and lower in the acid-neutral fraction than that of HT, respectively. More proline-¹⁴C of LT was converted to other amino acids, especially to acidic amino acids in free amino acid state, than was the HT proline-¹⁴C which had a comparatively wide distribution.

In the LT protein fractions. more proline-¹⁴C was incorporated into the cytoplasmic protein than into the cell wall protein. On the contrary, the radioactivity of the lIT cell wall increased more distinctively. proline-¹⁴C in the two proteins of LT was a little less converted to other amino acids than in those of HT. A little higher radioactivity was found in the aspartate and glutamate of the LT protein hydrolysates. The hydroxyproline which is closely related with proline had a little lower level of radioactivity in the LT cell wall.  相似文献   

Formation and properties of hydroxy iron(iii) oligomer-citrate complex     

Shin-Ichiro Wada  Takashi Ryu 《Soil Science and Plant Nutrition》2013,59(3):725-728

Instantaneous neutralization of Fe (III) chloride dissolved in N a citrate by powdery NaHC03 gave stable clear brown sols. The sol particles separated by dialysis and freeze-drying showed a single diffraction peak at 2 nm and a citrate/Fe molar ratio of about 0.2 irrespective of the composition of the starting solutions. This indicates that the product may be a novel phase of Fe (III) citrate.  相似文献   

The Use of Bacillus Licheniformis HA1 To Accelerate Composting of Organic Wastes     

Kiyohiko Nakasaki  Nobuyuki Uehara  Minoru Kataoka  Hiroshi Kubota 《Compost science & utilization》2013,21(4):47-51

The effect of Bacillus licheniformis HA1 cell density on the acceleration of organic waste composting was tested in a bench-scale composting system utilizing a process limit temperature of 60°C. Variables measured during composting were CO₂ evolution rate, conversion of substrate carbon and pH. When an initial cell density of 2.0×10⁴ cfu/g-dry solid was used, the strain HA1 increased in number and prevented the decrease in pH during the early stage of composting. This resulted in enhanced populations of other thermophiles and increased the rate of organic matter decomposition. By contrast, no effect was observed at a lower cell density of HA1. It was found that the minimum cell density of HA1 to accelerate organic decomposition was around 10⁴-10⁵ cfu/g dry solid of raw material.  相似文献   

Seaweeds and Their Natural Products for Preventing Cardiovascular Associated Dysfunction     

Bomi Ryu  Young-Sang Kim  You-Jin Jeon 《Marine drugs》2021,19(9)

Cardiovascular disease (CVD), which involves the onset and exacerbation of various conditions including dyslipidemia, activation of the renin–angiotensin system, vascular endothelial cell damage, and oxidative stress, is a leading cause of high mortality rates and accounts for one-third of deaths worldwide. Accordingly, as dietary changes in daily life are thought to greatly reduce the prevalence of CVD, numerous studies have been conducted to examine the potential use of foods and their bioactive components for preventing and treating CVD. In particular, seaweeds contain unique bioactive metabolites that are not found in terrestrial plants because of the harsh environment in which they survive, leading to in vitro and in vivo studies of their prevention and treatment effects. This review summarizes studies that focused on the beneficial effects of seaweeds and their natural products targeting markers involved in a cascade of mechanisms related to CVD pathogenesis. The purpose of this review is to describe the potential of seaweeds and their natural products for preventing and treating CVD based on in vivo and in vitro studies. This review provides a basis for future research in the field of marine drugs.  相似文献