中度嗜盐菌Martelella sp. AD-3 降解菲过程中水杨酸-5-羟化酶的酶学性质

[目的]研究中度嗜盐菌Martelella sp.AD-3在降解菲过程中水杨酸-5-羟化酶的活性与菲降解效率的关系及其酶学性质.[方法]通过HPLC分析菲的降解效率和AD-3菌粗酶液催化水杨酸的产物,根据NADH在340 nm处的吸光度变化计算水杨酸-5-羟化酶的活性.[结果]水杨酸-5-羟化酶是一种诱导酶,在AD-3菌的对数生长期和稳定初期时活性较高,酶活力大小与该菌对菲的降解速率基本一致.在菲浓度为200 mg/L、生长盐度为3％、pH为9.0的培养条件下,AD-3菌株表达的水杨酸-5-羟化酶的活力最高,为132.8 nmol/(min·mg).水杨酸-5-羟化酶催化水杨酸降解时的最适温度、pH和盐度分别为30℃、7.5和3％,酶的最大反应速率为200 nmol/(min· mg)、米氏常数Km为8.7μmol/L.[结论]AD-3菌在降解菲的过程中表达水杨酸-5-羟化酶,该酶的活性与菲降解速率具有相关性.     

猪丹毒丝菌天然SpaA和重组SpaA-N免疫保护效果的评价

【目的】本试验以小鼠为动物模型,评估了猪丹毒丝菌重组表面保护性抗原A的N端保护区域(rSpaA-N)和天然SpaA的免疫保护效果。【方法】将猪丹毒丝菌C43311株SpaA-N以可溶形式表达在大肠杆菌BL21中,用GST Bind Resin纯化试剂盒纯化rSpaA-N,采用电洗脱法从猪丹毒丝菌C43311株NaOH提取抗原中纯化天然SpaA,将rSpaA-N、天然SpaA和NaOH提取抗原制成亚单位疫苗,同时设GST及生理盐水对照组,间隔2周分3次皮下免疫小鼠,第3次免疫后2周用100LD50猪丹毒丝菌C43065株进行腹腔攻毒,采用间接ELISA方法检测免疫组小鼠血清的抗体动态变化。【结果】SDS-PAGE结果显示,采用GST Bind Resin纯化试剂盒和电洗脱法纯化得到了66kDa的rSpaA-N和64kDa的天然SpaA,蛋白含量分别为1.34mg/mL和1.26mg/mL,而Western印迹结果表明rSpaA-N和纯化前后的SpaA具有良好的免疫反应性。保护试验结果表明,不同免疫剂量的rSpaA-N组、天然SpaA组和NaOH提取抗原组均能完全保护小鼠受强毒株C43065的致死性攻击,而GST组和生理盐水组小鼠攻毒后全部死亡。ELISA检测结果表明,在不同免疫剂量的rSpaA-N组、天然SpaA组和NaOH提取抗原组小鼠血清中的抗体效价之间无显著差异(P0.05)。【结论】本研究结果表明rSpaA-N具有良好的免疫保护作用,可以作为猪丹毒亚单位疫苗。     

Metabolic changes of the reduction of manganese intake in the hepatic encephalopathy rat: NMR- and MS-based metabolomics study

BioMetals - To investigate the metabolic changes in type C hepatic encephalopathy (CHE) rats after reducing manganese (Mn) intake. A total of 80 Sprague–Dawley rats were divided into control...     

A Key Role of microRNA-29b for the Suppression of Colon Cancer Cell Migration by American Ginseng

Metastasis of colon cancer cells increases the risk of colon cancer mortality. We have recently shown that American ginseng prevents colon cancer, and a Hexane extract of American Ginseng (HAG) has particularly potent anti-inflammatory and anti-cancer properties. Dysregulated microRNA (miR) expression has been observed in several disease conditions including colon cancer. Using global miR expression profiling, we observed increased miR-29b in colon cancer cells following exposure to HAG. Since miR-29b plays a role in regulating the migration of cancer cells, we hypothesized that HAG induces miR-29b expression to target matrix metalloproteinase-2 (MMP-2) thereby suppressing the migration of colon cancer cells. Results are consistent with this hypothesis. Our study supports the understanding that targeting MMP-2 by miR-29b is a mechanism by which HAG suppresses the migration of colon cancer cells.     

Granulation of activated sludge in a continuous flow airlift reactor by strong drag force

Most aerobic granule cultivation has been based on the sequencing batch reactor (SBR) and then the factors that affect aerobic granulations were developed in the SBR. However, little work has been done to cultivate aerobic granules in a continuous-flow bioreactor with simple structure that is realistic for engineering. This work is the first to cultivate aerobic granules in a continuous flow airlift fluidized bed reactor (CAFB) possesses a very simple structure and without settling time and starvation time controlling. The configuration of CAFB was the simplest continuous-flow aerobic granular bioreactor reported by now. The majority of granules could be formatted in the CAFB after 12 days cultivation. The effluent COD concentration maintained at 50 ± 10 mg/L for the variable COD loading rate of 3.5 g COD/L/d and 4.8 g COD/L/d, which confirmed that the CAFB performed good anti-shock abilities. CAFB performed good nitrification ability, however, little denitrification was found under the operating conditions of this study. The shear stress acting on the solid phase were hundreds of times stronger in the CAFB than in the SBR at the same aeration strength. It seems CAFB is very efficient for granulation due to the strong shear-force exertion, which is promising for continuous-flow aerobic granular bioreactor. Protein, positive to the hydrophobicity, was predominant in extracellular polymeric substances in the granules, and favored the granules formation in the CAFB combined with the polysaccharides. However, filamentous bulking always happened in 35 days operation of the CAFB, thus further study on the stability of this bioreactor is urgently necessary.     

Synthesis and fungicidal activity of novel pyrazole derivatives containing 5-Phenyl-2-Furan

Pyrazole constitutes an important heterocyclic family covering a broad range of synthetic as well as natural products that exhibit numerous chemical, biological, agrochemical and pharmacological properties. In order to explore compounds with good fungicidal activity, a series of new pyrazole derivatives containing 5-phenyl-2-furan were designed and synthesized. In vitro and in vivo fungicidal activities were evaluated and the compound ethyl-1-(5-phenylfuran-2-carbonyl)-5-propyl-1H-pyrazole-3-carboxylate (I8) displayed significant fungicidal activity against various fungi, especially against P. infestans. The structures of the novel pyrazole derivatives were confirmed by ¹H NMR, ¹³C NMR, MS, elemental analysis and X-ray single crystal diffraction. Further study showed that compound I8 might act on the synthesis of cell walls from morphological and ultrastructural studies by SEM and TEM. The results also revealed that compound I8 could block the nutritional transportation leading to cells senescence and death. These results suggested that the novel pyrazole derivatives proved to be promising lead compounds.     

Linc01014 regulates gefitinib resistance in oesophagus cancer via EGFR‐PI3K‐AKT‐mTOR signalling pathway

This study aimed to explore the underlying mechanism of linc01014 in oesophagus cancer gefitinib resistance. Gefitinib‐resistant oesophagus squamous cell carcinoma (ESCC gefitinibR) cell lines were constructed by using different gefitinib treatment in FLO‐1, KYAE‐1, TE‐8 and TE‐5 cell lines and confirmed by MTS50 and proliferation assays. Expression of linc01014 was overexpressed/silenced in FLO‐1 cells followed by gefitinib treatment, and then, the apoptosis‐associated markers Bax and Bcl‐2, and PI3KCA in PI3K signalling pathway were determined using Western blotting. MST50 and morphology analyses showed that ESCC gefitinibR cell lines presented obvious gefitinib resistance than their parental ESCC cell lines. ESCC gefitinibR cell lines showed significantly higher proliferation abilities than their parental ESCC cell lines after treating with gefitinib. Overexpression of linc01014 significantly inhibited the apoptosis of FLO‐1 cells induced by gefitinib and silencing linc01014 obviously promoted the apoptosis of FLO‐1 cells induced by gefitinib. Silencing linc01014 could significantly increase the gefitinib chemotherapy sensitivity of oesophagus cancer via PI3K‐AKT‐mTOR signalling pathway.     

Estimates and Predictions of Coal Workers’ Pneumoconiosis Cases among Redeployed Coal Workers of the Fuxin Mining Industry Group in China: A Historical Cohort Study

This research was aimed at estimating possible Coal workers’ pneumoconiosis (CWP) cases as of 2012, and predicting future CWP cases among redeployed coal workers from the Fuxin Mining Industry Group. This study provided the scientific basis for regulations on CWP screening and diagnosis and labor insurance policies for redeployed coal workers of resource-exhausted mines. The study cohort included 19,116 coal workers. The cumulative incidence of CWP was calculated by the life-table method. Possible CWP cases by occupational category were estimated through the average annual incidence rate of CWP and males’ life expectancy. It was estimated that 141 redeployed coal workers might have suffered from CWP as of 2012, and 221 redeployed coal workers could suffer from CWP in the future. It is crucial to establish a set of feasible and affordable regulations on CWP screening and diagnosis as well as labor insurance policies for redeployed coal workers of resource-exhausted coal mines in China.     

Brassinosteroids promote development of rice pollen grains and seeds by triggering expression of Carbon Starved Anther,a MYB domain protein

Transport of photoassimilates from leaf tissues (source regions) to the sink organs is essential for plant development. Here, we show that a phytohormone, the brassinosteroids (BRs) promotes pollen and seed development in rice by directly promoting expression of Carbon Starved Anther (CSA) which encodes a MYB domain protein. Over‐expression of the BR‐synthesis gene D11 or a BR‐signaling factor OsBZR1 results in higher sugar accumulation in developing anthers and seeds, as well as higher grain yield compared with control non‐transgenic plants. Conversely, knockdown of D11 or OsBZR1 expression causes defective pollen maturation and reduced seed size and weight, with less accumulation of starch in comparison with the control. Mechanically, OsBZR1 directly promotes CSA expression and CSA directly triggers expression of sugar partitioning and metabolic genes during pollen and seed development. These findings provide insight into how BRs enhance plant reproduction and grain yield in an important agricultural crop.