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Rhodopseudomonas palustris strain PS3, a phototrophic bacterium, was originally isolated from a paddy field located in Taipei city, Taiwan, and showed positive effects on the growth of leafy vegetables. The aim of this study was to clarify the mechanism of the beneficial effects exerted by PS3 on plants. An ineffective R. palustris strain, YSC3, isolated from a paddy field located in Yilan County, was used as the negative control for comparative analyses. We cultivated non-heading Chinese cabbage (Brassica rapa var. chinensis) in 1/2 strength Hoagland hydroponic solution, in which nitrate is the main nitrogen source. We evaluated various plant physiological responses to inoculation with different bacterial inoculants. The N use efficiency (NUE) of PS3-inoculated plants was dramatically higher than that of YSC3-inoculated plants. The nitrate uptake efficiency (NUpE) was significantly elevated in plants treated with PS3; however, no excess nitrate accumulation was observed in leaves. We also noticed that the endogenous indole-3-acetic acid (IAA) levels as well as the cell division rate in the leaves of PS3-inoculated plants were significantly higher than those in the leaves of YSC3-inoculated plants. We examined the bacterial transcription of some genes during root colonization, and found that the expression level of IAA synthesis related gene MAO was almost the same between these two strains. It suggests that the elevated endogenous IAA in the PS3-inoculated plants was not directly derived from the exogenous IAA produced by this bacterium. Taken together, we deduced that PS3 inoculation could promote plant growth by enhancing nitrate uptake and stimulating the accumulation of endogenous auxin in young expanding leaves to increase the proliferation of leaf cells during leaf development.

Understanding the environmental niche segregation of ammonia-oxidizing archaea (AOA) and bacteria (AOB) and its impact on their relative contributions to nitrification and nitrous oxide (N2O) production is essential for predicting N2O dynamics within an ecosystem. Here, we used ammonia oxidizer-specific inhibitors to measure the differential contributions of AOA and AOB to potential ammonia oxidization (PAO) and N2O fluxes over pH (4.0-9.0) and temperature (10-45 °C) gradients in five soils and three wetland sediments. AOA and AOB activities were differentiated using PTIO (2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide), 1-octyne, and acetylene. We used square root growth (SQRT) and macromolecular rate theory (MMRT) models to estimate cardinal temperatures and thermodynamic characteristics for AOA- and AOB-dominated PAO and N2O fluxes. We found that AOA and AOB occupied different niches for PAO, and soil temperature was the major determinant of niche specialization. SQRT and MMRT models predicted a higher optimum temperature for AOA-dominated PAO and N2O fluxes compared with those of AOB. Additionally, PAO was dominated by AOA in acidic conditions, whereas both AOA- and AOB-dominated N2O fluxes decreased with increasing pH. Consequently, net N2O fluxes (AOA and AOB) under acidic conditions were approximately one to three-fold higher than those observed in alkaline conditions. Moreover, structural equation and linear regression modeling confirmed a significant positive correlation (R2 = 0.45, p

Armillariella mellea is an edible mushroom which contains important nutritious properties including proteins, cellulose, fatty acids, and polysaccharides (PSs). PSs and sulfated polysaccharides (SPSs) were prepared and their anti-inflammatory activities were studied from cultured A. mellea . Fucose, galactose, glucose, and mannose were the major sugars of SPSs and non-SPSs. The area percentage of high-molecular-weight SPSs of 1358 kDa and low-molecular-weight SPSs of 13.4 kDa covered over half of the SPS mixture. Secretions of tumor necrosis factor (TNF-α) and interleukin (IL)-6 after lipopolysaccharide (LPS) stimulation were detected in RAW264.7 macrophages. Time-course study showed that PSs from 49-day-cultured mycelia exhibited maximal inhibition of TNF-α and IL-6 with respective values of 31.17% and 62.74%. Harvest time is an important factor to obtain bioactive PSs. SPSs exhibited more-effective inhibition of TNF-α and IL-6 secretions compared to those of non-sulfated PSs with respective values of 100% and 56.82% suppression. IκB degradation induced by LPS in macrophages was reversed by PS and SPS pretreatment. Suppression of NF-κB activation might be responsible for their anti-inflammatory effects.

A study conducted in 2006 showed that over 100 ha of rice paddies in Beitou, Taiwan, irrigated over the years using water mixed with hot spring, was heavily polluted by arsenic. Thus, the objective of the present study is to measure arsenic content in different parts of rice and paddy soils, and eventually explain the arsenic distribution in ratoon rice, including its relationship to the soil. Arsenic levels of rice in grains, straws, roots, and soils were obtained from 15 rice paddies, selected based on different arsenic soil concentrations ranging from 67 to 438 mg kg−1 (n = 15). The mean arsenic content in grains was measured at 0.20 mg kg−1 (n = 60) and the highest grain arsenic of the survey was at 1.183 mg kg−1. Meanwhile, the mean total arsenic levels were 244 mg kg−1 (n = 28) in root and 4.4 mg kg−1 (n = 28) in straw. In comparison, regression of topsoil arsenic levels with rice grains (r2 = 0.00) and straws (r2 = 0.56) were less significant compared to that with rice roots (r2 = 0.93), and the mean arsenic level in rice from root to grain was also shown to have a decreasing trend. Though concentrations of arsenic in compositive rice grain each field did not exceed food hygiene concentration limit, arsenic level in root strongly depended on arsenic concentrations of soil suggesting that the high arsenic concentration may have the potential for translocation from root to grain which ultimately effects on the human health.

Synthesis of heat shock proteins (HSPs) in response to heat shock (HS) is essential for thermotolerance. The effect of a Ca(2+) chelator, EGTA, was investigated before a lethal HS treatment in soybean (Glycine max) seedlings with acquired thermotolerance induced by preheating. Such seedlings became non-thermotolerant with EGTA treatment. The addition of Ca(2+), Sr(2+) or Ba(2+) to the EGTA-treated samples rescued the seedlings from death by preventing the increased cellular leakage of electrolytes, amino acids, and sugars caused by EGTA. It was confirmed that EGTA did not affect HSP accumulation and physiological functions but interfered with the recovery of HS-released Ca(2+) concentration which was required for thermotolerance. Pectin methylesterase (PME, EC 3.1.1.11), a cell wall remodelling enzyme, was activated in response to HS, and its elevated activity caused an increased level of demethylesterified pectin which was related to the recovery of the HS-released Ca(2+) concentration. Thus, the recovery of HS-released Ca(2+) in Ca(2+)-pectate reconstitution through PME activity is required for cell wall remodelling during HS in soybean which, in turn, retains plasma membrane integrity and co-ordinates with HSPs to confer thermotolerance.

This research involved a magnetic resonance imaging (MRI) technique that was applied to examine water distribution and migration in single rice kernels during the tempering process. The imaging experiments were performed in a Bruker 9.4T MRI system. Three-dimensional spin-echo (SE) imaging sequences were optimized by adjusting the scanning parameters of echo time (TE) and repetition time (TR) to obtain images with maximum contrast. The MR images showed that the moisture distribution in the rice kernel is non-uniform and compartmental. The embryo region exhibited much higher MR signal intensity than the starchy endosperm portion. The tempering process was analyzed with spatial-temporal signal intensities of the endosperm following the drying process of the rice kernel. The transient change of the signal intensities in the endosperm was well fitted with a double exponential function suggesting that both convection and diffusion contributed to the reduction of the moisture gradient within the rice kernel during tempering. This hypothesis was further supported by the experimental data of the insulated rice kernel whose convective mass transfer was excluded. The experimental results revealed that MR imaging of rice kernels could be used as an efficient tool to examine the mechanisms of moisture migration within cereal grains.

Sulfated polysaccharides (SPSs) of Antrodia cinnamomea were extracted by an exhaustive papain digestion and characterized, and their biological functions were evaluated. In this study, we demonstrated the existence of SPSs in the medicinal fungus, A. cinnamomea . Since no SPSs had previously been identified in any fungal organism, we attempted to characterize those from A. cinnamomea . SPSs from A. cinnamomea inhibited in vitro Matrigel tube formation, in an angiogenesis model, in a dose-dependent manner. Furthermore, using serum deprivation-induced apoptosis in neuronal-like PC12 cells as a stress model, the SPSs of A. cinnamomea were effective in preventing serum-deprived apoptosis. Compositional analysis revealed that myo-inositol, fucose, galactose, and glucose were the neutral sugars in SPSs of A. cinnamomea , and these SPSs had a high sulfate content. The sulfation degree paralleled their antiangiogenic and neuroprotective activities. In this work, we report novel data on the structure, antiangiogenic, and neuroprotective effects of these fungal SPSs.

The involvement of ethylene and 1-aminocyclopropane-1-carboxylic acid (ACC) in shade-induced kernel abortion at an early kernel growth stage was investigated. Changes in levels of glucose, sucrose, starch, ACC and ethylene were measured during the first 6 days after pollination (DAP) at sampling intervals of 12 or 24 h. In response to shading treatment, dry weight accumulation of apical kernels ceased within 96 h after pollination (HAP). Glucose levels in shaded kernels 12 HAP were significantly higher than in control kernels, while sucrose and starch levels were similar until 48 HAP. In the shade treatment ACC and ethylene levels increased rapidly around 24 HAP in both apical and basal kernels. When ACC was applied to ears at 32 HAP and 5 DAP, dry weight accumulation was significantly reduced only in apical kernels of 32 HAP. Significant reduction in endosperm nuclei number was also found in both shaded and ACC-treated kernels. The results of the present study suggest that ethylene may be involved in the processes leading to kernel abortion in maize. Kernels at the very early developmental stages seem to be most sensitive to ethylene.

Fomitopsis pinicola is used as a medicinal fungus in Asia. Polysaccharides extracted from 35-day-cultured fungus and its ethanolic extract showed no toxicity to endothelial cells (ECs). Extracted polysaccharides had a strong inhibitory effect on vascular endothelial growth factor (VEGF)-induced tube formation in ECs in a dose-dependent manner. Furthermore, the ethanolic extract dose-dependently suppressed production of the interferon (IFN)-γ-induced inflammation marker, IP-10. High-molecular-weight of 5367 and 1056 kDa accounted for 19.6% and 19.3% of the total polysaccharides, and a low-molecular-weight one of 14.7 kDa accounted for 53.6% of the total polysaccharides. Chemical analyses of the polysaccharides revealed that myo-inositol, fucose, galactose, glucose, mannose, and fructose were neutral sugars in the polysaccharide. Six nucleoside-type compounds including cytidine, adenosine monophosphate (AMP), adenosine diphosphate (ADP), adenosine, inosine, and thymidine were identified in the ethanolic extract. These results suggest that different extracts from F. pinicola play different roles in regulating the angiogenic process and inflammation.

Carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranol-N-methylcarbamate) and carbaryl (1-naphthyl-N-methylcarbamate) are insecticides widely used in tea plantations. The objective of the present study was to evaluate the dissipation of carbofuran and carbaryl during the growth periods of Oolong tea, processing and roasting. Analysis of the residual insecticides was carried out using high-pressure liquid chromatography with a post-column fluorescence detector. Results showed that in the tea field carbofuran dissipated faster then carbaryl. Manufacturing processes of Oolong tea further reduced the carbofuran and carbaryl contents. The persistence of carbofuran and carbaryl was decreased with increasing roasting temperature. From the results, we conclude that the presence of carbofuran and carbaryl in tea can be reduced by proper field management, manufacturing and roasting processes.

Kernel abortion in maize (Zea mays L.) can cause significant reductions in yield. Abortion usually commences early in development and frequently occurs because of stresses such as water deficit or low light. Polyamines have been implicated in development processes of fruits and seeds, but in maize the changes of polyamine levels during kernel growth are still unclear. The objectives of this study were to investigate the roles of polyamines in the early stages of kernel growth and kernel abortion. Two single-cross hybrids with different kernel abortion characteristics were grown in a greenhouse with shade treatment. During early development of normal, naturally aborting, and shade-induced aborting kernels, temporal changes in the concentrations of endogenous putrescine (PUT), spermidine (SPD) and spermine (SPM) and their free, perchloric acid (PCA)-soluble conjugated, and PCA-insoluble bound forms, were measured. Changes in DNA content and the number of endosperm nuclei were also measured. Total polyamine levels in normal kernels rapidly increased 4 to 6 d after pollination (DAP), and peaked during active endosperm cell division. The most abundant polyamines were, in order, PCA-soluble conjugated PUT, PCA-soluble conjugated SPD, and free PUT. Aborting kernels had significantly lower levels of polyamines than normal kernels after 4 DAP. The low polyamine levels were temporally associated with a low number of endosperm nuclei and low DNA content. The results suggest that polyamines may be involved in the regulation of early endosperm development in maize.

Ozone is one of the major gaseous pollutants detrimental to crop growthand metabolism. The objective of this research was to study how ABA amelioratesthe effects of ozone on rice seedlings. Seedlings of two rice cultivars withdifferent sensitivities to ozone (Tainung 67, tolerant; and Taichung Native 1,sensitive) were treated with 400 ppb of ozone or ABA and 400ppb of ozone to determine their effect on growth, stomatalmovement, chlorophyll characteristics, and the activity of antioxidant enzymes.Activities of the enzymes SOD, APOD, GR and POD were significantly higher inthesensitive cultivar, TN 1, than in the tolerant cultivar, TNG 67. Seedlings ofthe sensitive cultivar pretreated with ABA (10 μM) weresignificantly more tolerant of ozone than control seedlings. Pretreatment withABA effectively reduced stomatal conductance and the degree of injury. Abscisicacid also increased ascorbate peroxidase and glutathione reductase activity.Ozone increased peroxidase activity in sensitive seedlings, but ABA decreasedperoxidase activity. The sensitive cultivar had a higher density of stomata onits leaves than the tolerant cultivar. The results suggest that ABA inducedtolerance to ozone may be more associated with its effects on stomatal movementthan on the modulation of antioxidant enzyme activity.

Soluble acidity has been used as one of major indexes to reflect the changes of rice (Oryza sativa L.) grain quality during storage. The acidity is in general visually examined by pH dye indicators or directly measured by a pH meter. By combining the characteristics of pH dye indicator, 96-well microplate, and microplate reader, we have developed a procedure capable of effectively measuring the pH value of rice grains at a single-grain level. First, from a pH-dye system prepared with methyl red and bromothymol blue, we scanned the spectral response to pH and determined that a wavelength of 630 nm showed the maximum response to pH changes with storage age of rice grains. By means of a 96-well microplate and plate reader, a pH standard curve was then constructed with a series of pH standard buffers and absorbance at 630 nm. The pH value of a single grain in a microplate well can be measured by incubating the grain with dye solution and reading absorbance. The proposed procedure offers an efficient means of measuring the change of soluble acidity in rice grains during storage on an individual-grain basis. The method may also rapidly detect the uniformity or blending status of fresh/old grains in a sample.

We have investigated the role of abscisic acid (ABA) in the regulation of polyamine biosynthesis in rice (Oryza sativa L.) seedlings exposed to chilling (5°C). In a chilling-tolerant cultivar (cv. Tainung 67, TNG.67), levels of free putrescine and activity of arginine decarboxylase (ADC, EC 4.1.1.19) in both shoots and roots, and levels of free spermidine/spermine and activity of S-adenosylmethionine decarboxylase (SAMDC, EC 4.1.1.50) in shoots increased after exposure to chilling. In a chilling-sensitive cultivar (cv. Taichung Native 1, TN.1), level of free putrescine and activity of ADC in shoots increased slightly after exposure to chilling while those in roots decreased. Activity of ornithine decarboxylase (ODC, EC 4.1.1.17) in both cultivars remained unchanged after exposure to chilling. α-Difluoromethylarginine (DFMA), an irreversible inhibitor of ADC, but not α-difluoromethylornithine (DFMO), an irreversible inhibitor of ODC, at 0.5 mM inhibited free putrescine accumulation in chilled TNG.67 and resulted in a decrease in chilling tolerance; a decrease in survival and an increase in electrolyte leakage. The effects of DFMA were partially reversed by the addition of 0.5 mM putrescine. In TNG.67, chilling induced an increase of free ABA levels first, then ADC activity and finally free putrescine levels. Fluridone, an inhibitor of ABA synthesis, at 0.5 mM inhibited the increase of free ABA levels, ADC activity and free putrescine levels in chilled TNG.67, and resulted in a less tolerance of TNG.67 to chilling; these effects could be reversed by the pre-chilling treatment of 10 μM ABA. Application of 10 μM ABA for 48 h before chilling not only rendered TN.1 tolerant to chilling but also induced a change of polyamine pattern to be similar to chilled TNG.67. It seems that, for the materials used in this study, one of strategies of rice seedlings to resist chilling stress is to raise ABA levels and, in turn, one of ABA's functions is to enhance the ADC-mediated putrescine synthesis.

Physiological and biochemical changes related to methyl jasmonate (MeJA)-induced chilling tolerance of rice (Oryza sativa L. cv. Taichung Native 1) seedlings were investigated. Treatment of whole plants with 10 mmol m -3 MeJA for 48 h before chilling (5 °C) was optimal for the induction of chilling tolerance. MeJA greatly improved the survival ratio of chilled seedlings and ameliorated chilling injury such as demolition of membrane structure (estimated by electrolyte leakage). MeJA also prevented water loss in chilled seedlings by reducing the opening of stomata and decreasing the root bleeding rate. Putrescine and spermine levels in shoots increased but spermidine levels decreased on exposure to MeJA. In roots, putrescine levels also increased and spermidine levels increased transiently on exposure to MeJA. Activities of arginine decarboxylase (ADC ; EC 4.1.1.19) and S-adenosylmethionine decarboxylase (SAMDC ; EC 4.1.1.50) in both shoots and roots increased on exposure to MeJA, while the activity of ornithine decarboxylase (ODC ; EC 4.1.1.17) remained unchanged. The MeJA-induced putrescine increase was inhibited by 50 mmol m -3 α-difluoromethylarginine (DFMA), an irreversible inhibitor of ADC, but not by 50 mmol m -3 α-difluoromethylornithine (DFMO), an irreversible inhibitor of ODC. The effect of MeJA on the induction of chilling tolerance was also reduced by 50 mmol m -3 DFMA. The effects of DFMA were partly prevented by 1 mol m -3 putrescine. This indicates that putrescine accumulation is required for the induction of chilling tolerance of rice seedlings by MeJA.

Changes of internal ABA levels in relation to anoxia- or ethylene-induced growth alterations were determined in etiolated rice ( Oryza sativa L. cv. Taichung Native 1) seedlings. An inverse relationship between ABA levels and growth was observed at the early growth stages of rice seedlings. When rice seedlings were exposed to anoxia or 10 μl/l ethylene, coleoptile elongation was enhanced while growth of roots and leaves was inhibited. In contrast, anoxia or ethylene induced a decrease of ABA levels in coleoptiles but an increase in roots and leaves, especially after 48 h of treatment. In addition, the anoxia- or ethylene-enhanced coleoptile elongation was inhibited by ABA ranging from 10 −7 M to 10 −4 M. Thus,results presented here indicate that ABA is an inhibitory modulator in the anoxia- or ethylene-induced morphological changes of etiolated rice seedlings.

Summary The role of abscisic acid (ABA), ethylene and polyamines in leaf senescence of tobacco exposed to flooding was investigated. Senescence of tobacco leaves was followed by measuring the decrease of protein. Flooding significantly promoted senescence of tobacco leaves and resulted in a higher ABA content than the controls throughout the entire 4-day experimental duration. Ethylene production in flooding-treated leaves was much higher than that in control leaves during the first day of the experiment. Putrescine and spermidine, but not spermine, were present in tobacco leaves throughout the experimental duration. Flooded leaves had higher levels of putrescine and spermidine than untreated leaves. It is concluded that ethylene, but neither ABA nor polyamines, is possibly involved in the regulation of flooding-promoted senescence of tobacco leaves.

The timing of developmental events and regulatory roles of auxin were examined in maize (Zea mays L.) endosperms. Zeatin, zeatin riboside, and indole-3-acetic acid (IAA) levels were determined by enzyme-linked immunosorbent (ELISA). Zeatin and zeatin riboside increased to maximal concentrations at an early stage (9 d after pollination [DAP]), corresponding to the stage when cell division rate was maximal. In contrast, IAA concentration was low at 9 DAP and abruptly increased from 9 to 11 DAP, thus creating a sharp decline in the cytokinin to auxin ratio. Coincident with the increase in IAA was an increase in DNA content per nucleus, attributed to postmitotic DNA replication via endoreduplication. Exogenous application of 2,4-dichlorophenoxyacetic acid (2,4-D) at 5 or 7 DAP hastened the time course of DNA accumulation per nucleus and increased the average nuclear diameter, whereas 2-(para-chlorophenoxy)isobutyric acid delayed such development. Exogenously applied 2,4-D hastened the accumulation of the zein polypeptides of apparent molecular masses of 12, 14, and 16 kD and the expression of mRNA hybridizing with a zein DNA probe. We conclude that an abrupt increase in auxin induces cellular differentiation events in endosperm, including endoredupliction and expression of particular zein storage proteins.

To provide insight into the regulatory roles of auxin and cytokinin in endosperm development, defective kernel ( dek ) mutants of maize ( Zea mays L.) were examined. The mutants dek 6, dek 18 and dek 26 had substantially lower indole-3-acetic acid (IAA) levels than wild-type counterparts while dek 8, dek 12 dek 24 had higher IAA levels than wild-type counterparts. The mutant dek 6 had a somewhat lower zeatin level than its wild-type counterpart. The mutation-induced changes in IAA levels and effects of exogenously-applied auxin were not consistently related to changes in numbers of nuclei per endorsperm; however, there was a correspondence between auxin level in endosperm and nuclear diameter, which is proportional to the extent of post-mitotic DNA synthesis (endoreduplication). We conclude that auxin may be involved in stimulating endoreduplication.

Changes of ABA levels in chilled rice (Oryza sativa L.) seedlings of two varieties were determined. On exposure to chilling, ABA concentration rapidly increased in the chilling-tolerant cultivar (cv. Tainung 67, TNG.67) but not in the chilling-sensitive cultivar (cv. Taichung Native 1, TN.1). Both detached shoots and roots of TNG.67 seedlings showed a significant ABA increase after exposure to chilling. TN.1 seedlings could not accumulate ABA under low temperature but well-watered status. Exogenous application of the ABA biosynthetic inhibitor, fluridone, reduced ABA accumulation, as well as survival ratio of chilled TNG.67 seedlings. Electrolyte leakage and leaf conductance were also increased by the inhibitor and the effects could be reversed by exogenously applied ABA. ABA concentrations in xylem sap of TNG.67 seedlings increased within 4 h after chilling, and this was temporally coincident with the reduction of leaf conductance. The roles of endogenous ABA in the tolerance of rice seedlings to chilling on a whole plant basis are discussed and suggested.

The present study was performed to understand the effects of high temperature (HT) during filling on the expression of storage proteins and the quality of rice grains. HT (35/30 °C day/night) reduced the weight, amylose content, and flour gel consistency of grains. It increased the accumulation of all classes of storage proteins at early filling stage but decreased the accumulation of prolamins at maturation. For albumins, the expressions of cyclophilin 2, peroxiredoxin, and HSP16.9 were differentially enhanced by HT. For globulins, HT decreased the accumulation of globulin but increased that of glyoxalase I and peroxiredoxin. HT enhanced the transcription of genes for glutelins, prolamins, globulins, and protein disulfide isomerase at early filling stage but decreased the expression of these genes at a later stage. Low amounts of prolamins and globulins, as well as low pH value, were found in sound, immature, and dead kernels grown under HT. The relationships among HT, storage proteins, and grain quality are discussed.

A multiresidue method was developed to determine 19 carbamate pesticides in tea samples. Optimizations of different parameters, such as the type of extraction solvents, clean-up cartridges, and elution solvents were carried out. The developed method used acetonitrile as extraction solvent, amino cartridge for adsorbents and acetone-n-hexane as the eluting solution. Nineteen carbamate residues were then analyzed by high-pressure liquid chromatography (HPLC) with fluorescence detector. The present results showed good linearity by correlation coefficients of more than 0.9999 for all analyses. Limits of detection and quantification varied from 0.0005-0.023 mg L(- 1), 0.008-0.077 mg L(- 1), respectively. Recoveries of sixteen carbamate pesticides ranged from 65% to 135% at the spiked level of 0.5, 1.0 and 2.0 mg L(- 1). The relative standard deviations were lower than 20% and coefficient of variations were lower than 15%. The results indicate that the proposed method provides an effective multi and trace level screening determination of carbamate pesticides residues for tea samples.