Synthesis of polyacrylamide/polystyrene interpenetrating polymer networks and the effect of textural properties on adsorption performance of fermentation inhibitors from sugarcane bagasse hydrolysate.

Economical removal of fermentation inhibitors from lignocellulosic hydrolysate plays a considerable role in bioconversion of lignocellulose biomass. In this work, the textural properties of polyacrylamide/polystyrene interpenetrating polymer networks (PAM/PS IPNs) on adsorption of fermentation inhibitors from sugarcane bagasse hydrolysate (SCBH) were investigated for the first time. The results showed that, the specific surface area, pore diameter and surface polarity had important influence on its adsorption performance towards sugars, organic acids, furans and acid-soluble lignin. The PAM/PS IPNs under the optimal copolymerization situation achieved the high selectivity coefficients of 4.07, 14.9, 21.2 and 25.8 with respective to levulinic acid, furfural, hydroxymethylfurfural (HMF) and acid-soluble lignin, and had a low total sugar loss of 2.09%. Overall, this research puts forward a design and synthetic strategy for adsorbent to remove fermentation inhibitors from lignocellulosic hydrolysate.

Adsorption Study of Acid Soluble Lignin Removal from Sugarcane Bagasse Hydrolysate by a Self-Synthesized Resin for Lipid Production.

An adsorption resin CX-6 was synthesized and used for acid soluble lignin (ASL) removal from sugarcane bagasse hydrolysate (SCBH). The adsorption conditions of pH value, amount of adsorbent, initial ASL concentration, and temperature on ASL adsorption were discussed. The results showed the adsorption capacity of ASL was negatively affected by increasing temperature, solution pH, and adsorbent dose, and was positively affected by increasing initial concentration. The maximum adsorption capacity of ASL was 135.3 mg/g at initial ASL concentration 6.46 g/L, adsorption temperature 298 K, and pH 1. Thermodynamic study demonstrated that the adsorption process was spontaneous and exothermic. Equilibrium and kinetics experiments were proved to fit the Freundlich isotherm model and pseudo-second-order model well, respectively. Fermentation experiment showed that the SCBH after combined overliming with resin adsorption as fermentation substrate for microbial lipid production by Trichosporon cutaneum and Trichosporon coremiiforme was as better as that of SCBH by combined overliming with active charcoal adsorption, and more efficient than that of SCBH only by overliming. Moreover, the regeneration experiment indicated that the CX-6 resin is easy to regenerate and its recirculated performance is stable. In conclusion, our results provide a promising adsorbent to detoxify lignocellulose hydrolysate for further fermentation.

Ecophysiological response of native and exotic salt marsh vegetation to waterlogging and salinity: Implications for the effects of sea-level rise.

The ecophysiological characteristics of native Phragmites australis and exotic Spartina alterniflora grown under waterlogging and salinity were investigated to explore their adaptation potential to sea level rise. The seasonal course of phenotypic traits, photosynthetic activity and chlorophyll fluorescence parameters of P. australis did not change remarkably under shallow flooding, whereas these variables were sensitive to increasing salinity. Waterlogging exacerbated the negative effects of salinity on shoot growth and photosynthetic activity of P. australis, and the combined stresses led to an absence of tassel and reproductive organs. By contrast, S. alterniflora performed well under both stresses and showed an obvious adaptation of salt secretion with increasing salinity. Light salinity was the optimal condition for S. alterniflora, and the tassel growth, chlorophyll content and fluorescence characters under moderate stresses did not differ notably. The Na+ and Cl- concentrations in leaves of both species increased, and the K+ content decreased in response to salinity. Under moderate and high saline levels, the ion concentrations in S. alterniflora were maintained at relatively consistent levels with increased salt secretion. We expect the degradation of P. australis and further colonization of S. alterniflora under prolonged flooding and saltwater intrusion from sea level rise on the coastline of China.

[Alternative stable states in coastal intertidal wetland ecosystems of Yangtze estuary, China]. / 长江口滨海湿地潮间带生态系统的多稳态特征.

Alternative stable states phenomenon widely exists in a variety of ecosystems and is closely related to ecosystem health and sustainable development. Although alternative stable states research has become the focus and hotspot of the ecology researches, only a few empirical evidences supported its behavior and mechanisms in coastal wetland ecosystems up to now. In our study, ta-king the intertidal wetland ecosystem in Chongming Dongtan Nature Reserve as study area, we aimed to: 1) test the existence of alternative stable states based on judgment conditions (bimodal characteristic and threshold effect) and determine the relative stable state types; 2) explore the formation mechanisms of alternative stable states by monitoring hydrological conditions, sediment accretion dynamics as well as vegetation growth parameters and analyzing the positive feedbacks between saltmarsh vegetation and sedimentary geomorphology. Our results showed that: 1) Normalized difference vegetation index (NDVI) frequentness distribution revealed obvious bimodality at saltmarsh pioneer zone. Propagule biomass threshold limited the establishment of plant patches representing the "saltmarsh" state. The presence of bimodality and biomass threshold demonstrated there are "mudflat" stable state and "saltmarsh" stable state with distinct structure and function in intertidal wetland ecosystem. 2) Current velocities, turbidities and direction perpendicular to the vegetation zone were the most important factors responsible for the sediments rapid accretion at saltmarsh pioneer zone in spring and summer. Sediments accretion significantly promoted the growth of saltmarsh plant. The positive feedbacks between plant growth and sediments accretion resulted in the formation of alternative stable states. 3) The expansion pattern of saltmarshes in the Chongming Dongtan intertidal wetland ecosystem also suggested that increases of sediments accretion could trigger the formation of "mudflat" stable state and "saltmarsh" stable state on landscape scale. The results from this study could enrich regime shift mechanisms researches and provide the scientific supports for coastal zone protection, restoration and comprehensive management, which could have important theoretical and practical meaning.

Responses of eastern Chinese coastal salt marshes to sea-level rise combined with vegetative and sedimentary processes.

The impacts of sea-level rise (SLR) on coastal ecosystems have attracted worldwide attention in relation to global change. In this study, the salt marsh model for the Yangtze Estuary (SMM-YE, developed in China) and the Sea Level Affecting Marshes Model (SLAMM, developed in the U.S.) were used to simulate the effects of SLR on the coastal salt marshes in eastern China. The changes in the dominant species in the plant community were also considered. Predictions based on the SLAMM indicated a trend of habitat degradation up to 2100; total salt marsh habitat area continued to decline (4-16%) based on the low-level scenario, with greater losses (6-25%) predicted under the high-level scenario. The SMM-YE showed that the salt marshes could be resilient to threats of SLR through the processes of accretion of mudflats, vegetation expansion and sediment trapping by plants. This model predicted that salt marsh areas increased (3-6%) under the low-level scenario. The decrease in the total habitat area with the SMM-YE under the high-level scenario was much lower than the SLAMM prediction. Nevertheless, SLR might negatively affect the salt marsh species that are not adapted to prolonged inundation. An adaptive strategy for responding to changes in sediment resources is necessary in the Yangtze Estuary.

[Application of locomotor activity test to evaluate functional injury after global cerebral ischemia in C57BL/6 mice].

OBJECTIVE: To evaluate the application of locomotor activity test in functional injury after global cerebral ischemia (GCI) in C57BL/6 mice. METHODS: GCI was induced by bilateral carotid arteries occlusion for 30 min in C57BL/6 mice. Mice were divided into sham group, GCI group and minocycline group. Saline or minocycline (45 mg/kg) was i.p. injected once daily for 6 d after ischemia. At Day 6 after ischemia, locomotor activity was recorded for 1 h in open field test. Total distance, central distance, central distance ratio, periphery distance, periphery distance ratio, central time and periphery time were used to evaluate the behavior characteristics of locomotor activity in C57BL/6 mice after ischemia. The survival neuron density was detected by Nissl staining in hippocampus, cortex and striatum. RESULTS: Compared with sham group, total distance, central distance and central time increased and periphery time decreased in C57BL/6 mice after GCI (Ps<0.05). However, minocycline significantly reduced the central distance and central time and increased the periphery time (Ps<0.05). Neurons were damaged in hippocampus, cortex and striatum after GCI, which manifested by decreased neurons and the most serious damage in hippocampal CA1 region. Minocycline significantly improved the neuron appearance and increased the neuron number in hippocampus and striatum (P<0.001 or P<0.05). CONCLUSION: Locomotor activity in open field test can objectively evaluate the behavior injury after GCI in mice. Central distance and central time can be used as indexes of quantitative assessment.

[Vulnerability assessment on the coastal wetlands in the Yangtze Estuary under sea-level rise].

To study the response of coastal wetlands to climate change, assess the impacts of climate change on the coastal wetlands and formulate feasible and practical mitigation strategies are the important prerequisite for securing coastal ecosystems. In this paper, the possible impacts of sea level rise caused by climate change on the coastal wetlands in the Yangtze Estuary were analyzed by the Source-Pathway-Receptor-Consequence (SPRC) model and IPCC definition on the vulnerability. An indicator system for vulnerability assessment was established, in which sea-level rise rate, subsidence rate, habitat elevation, inundation threshold of habitat and sedimentation rate were selected as the key indicators. A quantitatively spatial assessment method based on the GIS platform was established by quantifying each indicator, calculating the vulnerability index and grading the vulnerability index for the assessment of coastal wetlands in the Yangtze Estuary under the scenarios of sea-level rise. The vulnerability assessments on the coastal wetlands in the Yangtze Estuary in 2030 and 2050 were performed under two sea-level rise scenarios (the present sea-level rise trend over recent 30 years and IPCC A1F1 scenario). The results showed that with the projection in 2030 under the present trend of sea-level rise (0.26 cm x a(-1)), 6.6% and 0.1% of the coastal wetlands were in the low and moderate vulnerabilities, respectively; and in 2050, 9.8% and 0.2% of the coastal wetlands were in low and moderate vulnerabilities, respectively. With the projection in 2030 under the A1F1 scenario (0.59 cm x a(-1)), 9.0% and 0.1% of the coastal wetlands were in the low and moderate vulnerabilities, respectively; and in 2050, 9.5%, 1.0% and 0.3% of the coastal wetlands were in the low, moderate and high vulnerabilities, respectively.

[Distribution of soil carbon storage in different saltmarsh plant communities in Chongming Dongtan wetland].

Abstract: The high productivity of saltmarsh vegetation in coastal wetlands plays an important role on the formation of soil carbon pool. This paper studied the biomass difference, the spatiotemporal dynamics and vertical distribution of soil carbon storage in three dominant saltmarsh plant communities, i. e., Phragmites australis, Spartina alterniflora and Scirpus mariqueter in the Chongming Dongtan wetland, in the Yangtze Estuary. The results indicated that the gross biomass in the three saltmarsh plant communities was in the order of S. alterniflora (5750.7 g x m(-2)) > P. australis (4655.1 g x m(-2)) > S. mariqueter (812.7 g x m(-2)). The aboveground biomass was the highest in summer and autumn, and the underground biomass was the highest in winter. The soil carbon storage (0-50 cm) was the lowest in spring, gradually increased, and was the highest in winter. The annual increment of soil carbon storage decreased from the high tidal zone to the low tidal zone, and was in the order of P. australis community (711. 8 g x m(-2)) > S. alterniflora community (646.2 g x m(-2)) > S. mariqueter community (185.3 g x m(-2)) > bare mudflat (65.6 g x m(-2)). The highest value was in the 25-30 cm, 10-15 cm, 30-35 cm and 30-40 cm soil layers for bare mudflat and the S. mariqueter, S. alterniflora and P. australis communities, respectively. There was a significant linear relationship between the soil carbon storage and the underground biomass in the different saltmarsh communities.

[Responses of photosynthetic pigments of Spartina alterniflora and Phragmites australis to durative waterlogging].

With the invasive plant Spartina alterniflora and indigenous plant Phragmites australis in Chongming Dongtan Nature Reserve of Shanghai as test objects, the responses of their photosynthetic pigmentsto durative waterlogging were studied during the growth season in 2008. The basic composition and the content of the pigments differed with plant species, and their responses to durative waterlogging also differed. Under durative waterlogging stress, S. alterniflora had the decreased contents of chlorophyll a, b and carotenoid but the increased chlorophyll a/b and carotenoid/chlorophyll ratios, whereas P. australis had the increased pigment contents and rather constant chlorophyll a/b and carotenoid/chlorophyll ratios. After the waterlogging stress relieved, the pigment contents of S. alterniflora increased and its chlorophyll a/b and carotenoid/chlorophyll ratios decreased to the levels of the control, whereas the pigment contents of P. australis were significantly higher than the control. Both S. alterniflora and P. australis showed a compensatory effect after the stress relieved. P. australis could better adapt to the waterlogging stress than S. alterniflora, being able to be used as a substitutive plant for the restoration of coastal wetlands.

[Evaluation on a demonstration project of ecological restoration of ditches at Qianwei Village of Chongming County, Shanghai].

By using biological slope-protection techniques, oxidation pond system, and zeolite treatment system, a demonstration project of ecological restoration of ditches at the Qianwei Village of Chongming County in Shanghai was implemented, and an evaluation on the project was made via a runoff simulation experiment and the measurements of the parameters soil shear strength, biodiversity, and ditch water quality. The results showed that covering the dich slopes with shrub could significantly increase soil shear strength, compactness and moisture content, and the formed vegetation had significant effects on retarding runoff and removing TSS (P < 0.05). Applying live fascines could significantly increase soil shear strength and TSS removal rate (P < 0.05), but its effects on increasing soil compactness and moisture content and retaining runoff were not significant. After the implement of the demonstration project, the total N and P concentrations in ditch water decreased significantly, habitat quality and aesthetic value of ditch slope improved, and biodiversity enhanced greatly. The integration of the biological techniques with other ecological restoration measures could stabilize ditch slope, improve ditch habitat quality, and restore the ecological environment of the ditches.

[Population expansion of Spartina alterniflora and Phragmites australis at Jiuduansha, Shanghai based on cellular automata model].

Based on the field survey and the interpretation and analysis of satellite images about the population expansion patterns of Spartina alterniflora and Phragmites australis at Jiuduansha shoals in 1997-2004, and combined with 3S techniques, a cellular automata (CA) model was built to simulate the population dynamics of plants adaptable to salt marsh. The results showed that the model could well simulate the population expansion pattern and trend of S. alterniflora and P. australis at Jiuduansha, and strongly supported the hypothesis of space pre-emption and range expansion with simple advancing wave fronts of these two species. The native species P. australis shared the same niche with the exotic species S. alterniflora, but the range expansion rate of S. alterniflora was 2-4 times faster than that of P. australis. With the accretion of the Jiuduansha shoals, a rapid range expansion of S. alterniflora was predicted to last for a long period in the future. The CA model built in this study could gain valuable insights into the relationships between population expansion pattern and its ecological processes of exotic plant species, and was of significance for wetland biodiversity conservation and resources management.

[Maize transformation using xylose isomerase gene as a selection marker].

The xylA gene, encoding xylose isomerase, was cloned as a 1342-bp BamHI/SacI fragment from the E. coli. As a selection marker, the xylA gene was fused between the enhanced CaMV 35S promoter (E35S) and terminator (35St) in pBAC413 (Fig.2). pBAC413 was constructed to prevent the expression of sbeIIb in maize. PDS1000/He was used to bombard maize calli, which were induced to form by the elite inbred lines. The selection was carried out on the media containing concentrations of xylose from 0 to 100%. The results showed that the media containing 50% to 100% D-xylose were better, but differed with the genotype of maize (Tables 1 and 2). Successful integration of xylA gene into the maize genome was confirmed by DNA dot blotting, PCR and PCR-Southern hybridization (Figs.4 to 6). A method was established in which transformed maize cells were successively screened on a medium containing xylose instead of antibiotic and herbicide for bio-safety.

Induced expression of DREB transcriptional factor and study on its physiological effects of drought tolerance in transgenic wheat.

Expression vector pBAC128F, which carries DREB transcriptional factor gene driven by drought inducing promoter rd29B and bar gene driven by CaMV 35S promoter and maize Adh1 gene first intron, was transferred into the explants of immature inflorescence and immature embryos of hexaploid winter wheat cv. 8901, 5-98, 99-92 and 104 by particle bombardment. More than 70 resistant transgenic plants were obtained. Genomic PCR and RNA dot blotting analyses showed that DREB gene had been integrated into wheat genome of the transgenic plants (T0 and T1) and was well expressed in offspring seed of different transgenic lines. The content of proline in leaves and seeds of T2 transgenic lines was analyzed. Among 16 tested transgenic lines, 10 transgenic lines exhibited more than two fold of proline level in leaves as compared with CK plants. Under drought condition, after stopping water for 15 days the leaves of transgenic lines were still green, while CK were faded. After rewatering for 10 days, the leaves of transgenic lines maintained their green, while all CK plants were dead. Our research suggested that introducing a novel DREB transcriptional factor into wheat is an effective way to improve its drought-tolerance ability.