优化细胞表面组分与结构以提高P.Putida 5-x细胞的重金属吸附能力

研究了生物吸附剂Pseudomonas putida 5-X细胞的最佳制备条件,以提高其对重金属的吸附能力。并用Pseudomonas putida 5-X细胞为生物吸附剂处理含铜离子城市污水。实验结果表明,在优化的条件下,Pseudomonas putida 5-x细胞对铜离子的吸附容量可达87．3mg／g,经生物吸附过程处理后,废水中Cu^2 的含量降低至微量级,而且该吸附剂可有效循环使用5次。     

Contributions to the Flora of Spitsbergen,especially of Red bay,from the Collections of W. S. Bruce,F.R.S.G.S., Naturalist to the Prince of Monaco's Expeditions of 1898 and 1899

Background: Prescribed burning in peatlands is controversial due to concerns over damage to their ecological functioning, particularly regarding their key genus Sphagnum. However, empirical evidence is scarce.

Aims: The aim of the article is to quantify Sphagnum recovery following prescribed burns.

Methods: We completed nine fires at a raised bog in Scotland, achieving a range of fire severities by simulating drought in some plots. We measured Sphagnum cover and chlorophyll fluorescence F_v/F_m ratio (an estimate of photosynthetic capacity) up to 36 months post-fire.

Results: Cover of dominant Sphagnum capillifolium was similar in unburnt and burnt plots, likely due to its high moisture content which prevented combustion. Burning decreased S. capillifolium F_v/F_m 5 months after fire from 0.67 in unburnt plots to 0.44 in low fire severity plots and 0.24 in higher fire severity (drought) plots. After 22 months, F_v/F_m in burnt plots showed a healthy photosynthetic capacity of 0.76 and no differences between severity treatments. Other Sphagnum species showed similar post-fire recovery though their low overall abundance precluded formal statistical analysis.

Conclusions: S. capillifolium is resilient to low–moderate fire severities and the same may be true for a number of other species. This suggests that carefully applied managed burning can be compatible with the conservation of peatland ecosystem function.     

Sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust enzymatic saccharification of hardwoods

This study demonstrates sulfite pretreatment to overcome recalcitrance of lignocellulose (SPORL) for robust bioconversion of hardwoods. With only about 4% sodium bisulfite charge on aspen and 30‐min pretreatment at temperature 180°C, SPORL can achieve near‐complete cellulose conversion to glucose in a wide range of pretreatment liquor of pH 2.0–4.5 in only about 10 h enzymatic hydrolysis. The enzyme loading was about 20 FPU cellulase plus 30 CBU β‐glucosidase per gram of cellulose. The production of fermentation inhibitor furfural was less than 20 mg/g of aspen wood at pH 4.5. With pH 4.5, SPORL avoided reactor corrosion problem and eliminated the need for substrate neutralization prior to enzymatic hydrolysis. Similar results were obtained from maple and eucalyptus. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009     

化学处理方法对木质纤维素降解效率的影响评述

纤维素乙醇是生物质能源的重要发展方向。为了提高纤维素和半纤维素的降解效率,以酸化、碱化、氧化、有机溶剂、离子液处理为代表的木质素去除方法成为近年来的研究热点。常温常压条件下有效去除木质素的化学方法,必将加速纤维素乙醇的产业化进程。     

Effect of the chemical and physical condition of the soil on Verticillium wilt of antirrhinum

Summary In vitro study showed thatVerticillium dahliae Kleb. grew well in a wide range of acid and alkaline media (viz. pH 3.5 to 10.5). The best growth of the fungus was observed in pH 5.5. Soil pH 3.5 was toxic for growing antirrhinum seedlings. Development of Verticillium wilt of antirrhinum was affected by soil pH. The severity of the disease was greater in alkaline soil conditions compared with acid conditions. Soil of pH 3.5 gave very good control of the symptom expression by the infected plants. Rhizosphere analysis results showed that fungal population with the exception ofPenicillium spp., was drastically reduced in the rhizosphere of the plants grown in acid soil. Although the overall population of fungi was reduced in theV. dahliae infected antirrhinum rhizosphere in acid soil, the population ofPenicillium spp. markedly increased. The antagonistic activity of thePenicillium spp. in the rhizosphere might also have reduced the disease severity. Since the seedlings did not grow properly in very dry and very wet soil, rhizosphere analysis of these soils was not possible. Disease severity was much less in wet soil compared with plants grown in medium moisture level and dry soil, but the plant growth was very poor. Dedicated to the memory of the late Prof. H. K. Baruah from whom I had the inspiration for research     

Association of chemerin levels in synovial fluid with the severity of knee osteoarthritis

Context: Chemerin has been implicated to be correlated with inflammation.

Objective: This study aims to determine the association of chemerin levels in serum and synovial fluid (SF) with the disease severity of patients with knee Osteoarthritis (OA).

Methods: 124 patients with knee OA and 76 healthy controls were enrolled in this study.

Results: Chemerin levels in serum were significant higher with regard to paired SF. Chemerin levles in SF of knee OA patients were correlated with disease severity evaluated by KL grading criteria.

Conclusion: Chemerin levels may be involved in the pathophysiology of the development and progression of OA.     

Selection and optimization of a suitable pretreatment method for miscanthus and poplar raw material

Miscanthus and poplar are very promising second‐generation feedstocks due to the high growth rates and low nutrient demand. The aim of the study was to develop a systematic approach for choosing suitable pretreatment methods evaluated with the modified severity factor (log ). Optimal pretreatment results in a high delignification grade, low cellulose solubilization and increased accessibility for enzymatic hydrolysis while revealing minimal log values. In order to do so, several reaction approaches were compared. Acid‐catalyzed organosolv processing carried out for miscanthus and poplar revealed the highest delignification grade leading to a relatively high glucose yield after enzymatic saccharification. In both cases, a design of experiments approach was used to study the influence of relevant parameters. Modeling the data resulted in the identification of optimum pretreatment conditions for miscanthus with concentrations of 0.16% H₂SO₄ and 50% EtOH at 185°C for a retention time of 60 min. Experimental validation of these conditions revealed an even higher delignification degree (88%) and glucose yield (85%) than predicted. 0.19% H₂SO₄ and 50% EtOH were determined as optimum concentrations, 182°C and 48 min identified as optimum pretreatment conditions for poplar; the delignification degree was 84% and the resulting glucose yield 70%.     

Mild hypothermia pretreatment protects hepatocytes against ischemia reperfusion injury via down-regulating miR-122 and IGF-1R/AKT pathway

BackgroundMild hypothermia has been well known as an effective way to reduce ischemia reperfusion injury (IRI), while the mechanisms are still unclear. More and more evidences have indicated that miRNAs should been involved in the regulation of IRI and expecially some miRNAs have shown temp-responsiveness for temperature variation. Therefore, the role of miR-122 in mild hypothermia pretreatment after IRI was investigated.MethodsWe established a LO2 cell anoxia-reoxygenation injury model to simulate liver IRI. Five groups of differently pretreated L02 cells were studied. ALT, AST and LDH as well as cell viability were measured. Flow cytometric analysis was used to evaluate the apoptosis. The expression of miR-122 was quantified by qRT-PCR. Insulin-like growth factor 1 receptor (IGF-1R), protein kinase B (p-AKT), AKT, forkhead box O3a (p-FOXO3a) and Caspase3 were examined using western blot analysis.ResultsWe found that mild hypothermia pretreatment could reduce the hepatocellular injury and induce a significant down-regulation in miR-122 expression after IRI. However, those effects of protection were attenuated by overexpressed miR-122 blockade. We further demonstrated that down-regulation of miR-122 promoted IGF-1R translation and AKT activity, suppressed FOXO3a activity and Caspase3 expression after mild hypothermia pretreatment, which was abrogated by miR-122 mimic.ConclusionOur data clearly demonstrate that mild hypothermia pretreatment can down-regulate miR-122 to protect hepatocytes against IRI through activation IGF-1R/AKT signaling pathway and inhibit cells apoptosis.     

Analysis of exposed cellulose surfaces in pretreated wood biomass using carbohydrate‐binding module (CBM)–cyan fluorescent protein (CFP)

In enzymatic saccharification of lignocellulosics, the access of the enzymes to exposed cellulose surfaces is a key initial step in triggering hydrolysis. However, knowledge of the structure–hydrolyzability relationship of the pretreated biomass is still limited. Here we used fluorescent‐labeled recombinant carbohydrate‐binding modules (CBMs) from Clostridium josui as specific markers for crystalline cellulose (CjCBM3) and non‐crystalline cellulose (CjCBM28) to analyze the complex surfaces of wood tissues pretreated with NaOH, NaOH–Na₂S (kraft pulping), hydrothermolysis, ball‐milling, and organosolvolysis. Japanese cedar wood, one of the most recalcitrant softwood species was selected for the analysis. The binding analysis clarified the linear dependency of the exposure of crystalline and non‐crystalline cellulose surfaces for enzymatic saccharification yield by the organosolv and kraft delignification processes. Ball‐milling for 5–30 min increased saccharification yield up to 77%, but adsorption by the CjCBM–cyan fluorescent proteins (CFPs) was below 5%. Adsorption of CjCBM–CFPs on the hydrothermolysis pulp were less than half of those for organosolvolysis pulp, in coincidence with low saccharification yields. For all the pretreated wood, crystallinity index was not directly correlated with the overall saccharification yield. Fluorescent microscopy revealed that CjCBM3–CFP and CjCBM28–CFP were site‐specifically adsorbed on external fibrous structures and ruptured or distorted fiber surfaces. The assay system with CBM–CFPs is a powerful measure to estimate the initiation sites of hydrolysis and saccharification yields from chemically delignified wood pulps. Biotechnol. Bioeng. 2010; 105: 499–508. © 2009 Wiley Periodicals, Inc.