Crystalline, thermal and swelling properties of starches from single-segment substitution lines with different Wx alleles in rice (Oryza sativa L.).

BACKGROUND: In rice, five common Wx alleles, wx, Wxt , Wxg1 , Wxg2 and Wxg3 , have been identified according to their apparent amylose content (AAC) phenotypes. Previous studies revealed that this Wx allelic variation may also affect other starch properties. However, so far, to what extent the five Wx alleles influence the crystalline structure, thermal and swelling properties of rice starch is still unclear. For this purpose, a set of single-segment substitution lines (SSSLs) harboring five different Wx alleles, varying widely in AAC, was used for comparative studies. RESULTS: The crystalline structure, thermal properties and swelling behavior of starches from the SSSLs varied widely depending on Wx genotype. Effects of different Wx alleles on relative crystallinity followed the order wx > Wxt > Wxg1 = Wxg2 > Wxg3 . The glutinous and Wxt genotype starches showed higher gelatinization temperatures and enthalpy compared with other Wx genotypes. The order for swelling power was wx > Wxt > Wxg1 > Wxg2 > Wxg3 , while the order for degree of solubility was Wxg3 > Wxg1 > Wxg2 > Wxt = wx. Correlation analysis indicated that AAC was significantly and negatively correlated with relative crystallinity (r = -0.996, P < 0.01) and swelling power (r = -0.982, P < 0.01). CONCLUSION: The present results provide new knowledge about the influence of different Wx alleles on the structural and physicochemical properties of rice starch. © 2016 Society of Chemical Industry.

Swine manure treatment by anaerobic membrane bioreactor with carbon, nitrogen and phosphorus recovery.

Swine manure wastewater was treated in an anaerobic membrane bioreactor (AnMBR) that combined a continuous stirred tank reactor (CSTR) and a hollow-fiber ultrafiltration membrane, and the feasibility of ammonia and phosphorus recovery in the permeate was investigated. The AnMBR system was operated steadily with a high mixed liquor suspended solids (MLSS) concentration of 32.32 ± 6.24 g/L for 120 days, achieving an average methane yield of 280 mL/gVSadded and total chemical oxygen demand removal efficiency of 96%. The methane yield of the AnMBR is 83% higher than that of the single CSTR. The membrane fouling mechanism was examined, and MLSS and the polysaccharide contents of the extracellular polymeric substances were found to be the direct causes of membrane fouling. The effects of the permeation/relaxation rate and physical, chemical cleaning on membrane fouling were assessed for membrane fouling control, and results showed that a decrease in the permeation/relaxation rate together with chemical cleaning effectively reduced membrane fouling. In addition, a crystallization process was used for ammonia and phosphorus recovery from the permeate, and pH 9 was the optimal condition for struvite formation. The study has an instructive significance to the industrial applications of AnMBRs in treating high strength wastewater with nutrient recovery.

Simultaneous production of high-frequency synthetic apomixis with high fertility and improved agronomic traits in hybrid rice.

The current apomixis system used in fixing heterozygosity suffers from the problems of low fertility and limited apomixis induction rate. This study implies that egg-cell-specific expression of dandelion's PAR combined with MiMe in hybrid rice can efficiently trigger highly fertile synthetic apomixis for effective clonal propagation of hybrids.

Effects of pH on ex-situ biomethanation with hydrogenotrophic methanogens under thermophilic and extreme-thermophilic conditions.

Ex-situ biogas upgrading based on hydrogenotrophic methanogenic process has attracted much attention with the depletion of fossil fuels. Consumption of CO2 leads to the pH increase in the mixed cultures of biogas upgrading system. The hydrogenotrophic methanogens were enriched at pH 5.5-6.0, 7.0-7.5, and 8.5-9.0 and at 55°C and 70°C. The methane production activity and microbial community structure were evaluated. Semi-continuous experimental results showed that stable and similar methane production was obtained at pH 7.0-7.5 and 8.5-9.0. In addition, pH 8.5-9.0 presented higher maximum methane production rate compared to pH 7.0-7.5. pH below 6 obtained the longest lag phase time of about 17.4 h, more than twice the values at pH 7.0-7.5 (8.8 h) and pH 8.5-9.0 (6.9 h) at 55°C. The predominant methanogen was the genus Methanothermobacter, a hydrogenotrophic methanogen at higher temperatures. Methanobacterium became predominant at pH 8.5-9.0 and the abundance increased to 83.6% at 55°C. Coprothermobacter and Caldanaerobacter were identified as the core functional bacteria under alkaline condition and were likely involved in syntrophic acetate oxidation with hydrogenotrophic methanogens.

Anti-inflammatory properties of uvaol on DSS-induced colitis and LPS-stimulated macrophages.

BACKGROUND: Apocynum venetum leaves are used as a kind of phytomedicine and the main ingredient in some traditional Chinese medicine products for the relief of colitis. To understand the bioactive constituents of A. venetum L., we did a phytochemistry study and investigated anti-Inflammatory effects of compounds and explored the underlying mechanisms. METHODS: We isolated compounds from ethanol extract of A. venetum L. leaf and detected the most effective compound by NO inhibition assay. We investigated anti-Inflammatory effects on dextran sulfate sodium (DSS)-induced colitis mice and lipopolysaccharide (LPS)-stimulated RAW264.7 cells. The disease activity index was determined by scores of body weight loss, diarrhea and rectal bleeding; histological damage was analyzed by H&E staining; macrophages change in the colon were analyzed by immunohistochemistry (IHC); myeloperoxidase activity was measured by myeloperoxidase assay kits; levels of proinflammatory cytokines were determined by qPCR and ELISA; protein production such as COX-2, iNOS, STAT3 and ERK1/2 were determined by western blotting. RESULTS: We isolated uvaol from ethanol extract of A. venetum L. leaf and found uvaol has excellent potential of inhibiting NO production. We further found uvaol could attenuate disease activity index (DAI), colon shortening, colon injury, and colonic myeloperoxidase activity in DSS-induced colitis mice. Moreover, uvaol significantly reduces mRNA expression and production of pro-inflammatory cytokines (TNF-α, IL-6, IL-1ß, and MCP-1) and infiltration of macrophages in colonic tissues of colitis mice. Studies on LPS challenged murine macrophage RAW246.7 cells also revealed that uvaol reduces mRNA expression and production of pro-inflammatory cytokines and mediators. Mechanically, uvaol inhibits the pro-inflammatory ERK/STAT3 axis in both inflamed colonic tissues and macrophages. CONCLUSIONS: A. venetum leaf contains uvaol and uvaol has potent anti-inflammatory effects on DSS-induced experimental colitis and LPS-stimulated RAW264.7 macrophage cells. These results suggest uvaol is a prospective anti-inflammatory agent for colonic inflammation.

The calcium sensor OsCBL1 modulates nitrate signaling to regulate seedling growth in rice.

Nitrate signaling integrates and coordinates gene expression and plant growth; however, the underlying molecular mechanisms involved remain poorly understood. Our previous study revealed that rice calcineurin B-like protein 1 (OsCBL1) modulates lateral root elongation by affecting auxin biosynthesis. Here, we report that OsCBL1 also modulates nitrate signaling to regulate rice seedlings growth. Compared with wild-type seedlings, seedlings of OsCBL1-knockdown (OsCBL1-KD) plants showed a suppressed growth phenotype, which included reduced root and shoot fresh weights and shorter radicles, crown roots, and lateral roots, when grown in nitrogen-free conditions. Although the growth defects of OsCBL1-KD plants could be partially rescued by the addition of nitrate to the growth conditions, the nitrate uptake capability of the OsCBL1-KD plants did not differ from that of wild-type plants as assessed via nitrate content and 15NO3- influx experiments. The nitrate-regulated expression of nitrate signal sentinel genes (OsNRT2.1 and OsNRT2.2) was affected in the OsCBL1-KD plants under both long- and short-term nitrate treatments. Overall, our results showed a novel role for OsCBL1 in the regulation of nitrate signaling and nitrate-mediated rice growth.

Impaired Magnesium Protoporphyrin IX Methyltransferase (ChlM) Impedes Chlorophyll Synthesis and Plant Growth in Rice.

Magnesium protoporphyrin IX methyltransferase (ChlM) catalyzes the formation of magnesium protoporphyrin IX monomethylester (MgPME) from magnesium protoporphyrin IX (MgP) in the chlorophyll synthesis pathway. However, no ChlM gene has yet been identified and studied in monocotyledonous plants. In this study, a spontaneous mutant, yellow-green leaf 18 (ygl18), was isolated from rice (Oryza sativa). This mutant showed yellow-green leaves, decreased chlorophyll level, and climate-dependent growth differences. Map-based cloning of this mutant identified the YGL18 gene LOC_Os06g04150. YGL18 is expressed in green tissues, especially in leaf organs, where it functions in chloroplasts. YGL18 showed an amino-acid sequence similarity to that of ChlM from different photosynthetic organisms. In vitro enzymatic assays demonstrated that YGL18 performed ChlM enzymatic activity, but ygl18 had nearly lost all ChlM activity. Correspondingly, the substrate MgP was largely accumulated while the product MgPME was reduced in ygl18 leaves. YGL18 is required for light-dependent and photoperiod-regulated chlorophyll synthesis. The retarded growth of ygl18 mutant plants was caused by the high light intensity. Moreover, the higher light intensity and longer exposure in high light intensity even made the ygl18 plants be more susceptible to death. Based on these results, it is suggested that YGL18 plays essential roles in light-related chlorophyll synthesis and light intensity-involved plant growth.

[Inheritance and expression of the maize pepc gene in progenies of transgenic rice bred by crossing].

By cross breeding, the maize pepc gene in the pepc transgenic rice was successfully incorporated into the parents of two-, three-line hybrid rice, including sterile lines (Peiai64S, 2302S, 2304S, 2306S and Shuangjiu A) and restorer lines (5129, 02428 and Wanjing97) to breed the high-photosynthetic efficiency parents of hybrid rice and utilize heterosis between C4 and C4/C3 rice. Some lines of pepc transgenic rice (LPTR) have been developed. The study on the generations of LPTR suggests the following: (1) The segregation observed in F2 and BC1 progenies demonstrated that pepc transgene inherited as a single dominant gene in the progenies of LPTR. (2) The maize pepc gene is actively expressed at high level in LPTR, and changes of pepc gene expression in the progenies of LPTR may be related to position effect, difference of gene copy number and environmental factors. (3) Through the selection method of soaking seeds into hygromycin solution to germinate, tracing the pepc gene by PCR analysis, evaluating the performance of the rice plants in the field and examining PEPC activities, the segregation of the pepc transgene in LPTR was controlled effectively. Based on the above strategy three pepc transgene lines, H1596, H1597 and Y1470, have been selected. The result suggests that it is possible to breed practical, stable and high-expression pepc transgenic rice by conventional crossing.