禾本红酵母Y－5对结晶紫、孔雀石绿的吸附

研究了培养时间、初始pH、温度对禾本红酵母Y-5吸附结晶紫、孔雀石绿的影响,并对吸附剂的解吸和循环利用等进行考察.结果表明： 在染料浓度为50 mg·L^-1、pH 7.0、摇床转速150 r·min^-1、30 ℃、吸附10 h时,红酵母对结晶紫、孔雀石绿的吸附率分别达峰值,为93.8%和87.7%;解吸后的菌体对结晶紫、孔雀石绿的吸附率分别为85.5%和78.5%,说明菌体对染料的吸附是可逆的,循环利用效果良好,菌体可再生和循环利用;禾本红酵母Y-5对结晶紫、孔雀石绿的脱色机理为吸附作用,染料多被吸附在红酵母表面的羟基（-OH）上,其吸附染料快速、高效、可逆,在染料废水处理上具有潜在的应用价值.     

外来湿地植物再力花适生性分析

通过修改过的澳大利亚杂草评估系统(Australia Weed Risk Assessment System),气候匹配模型(MaxEnt)以及越冬实验对外来湿地植物再力花(Thalia dealbata)的适生性进行了分析.澳大利亚评估系统的评分为18分,远超过系统本身阈值(6分).MaxEnt分布区预测结果表明,再力花可以在北京—郑州—西安—成都—丽江一线以东生长,江浙一带以及安徽省东南部尤其适合再力花的生长.冷冻实验表明,经过2个月0℃低温处理的再力花虽然在生物量及开花数量上与低温处理时间较短的植株存在显著差异,但是却依然可以完成整个生活史.结果表明,再力花在中国大部分区域都可以生长,可能具有入侵风险.     

再力花处理河涌和湖泊水样有机污染物及离子的特性

为了明确河涌和湖泊水样中COD、TP、TN和阴阳离子的植物处理效果,以及含氮污染物的植物转化规律,以前期研究中选育的再力花处理了广州市某河涌和暨南大学明湖水样.结果证明,再力花能有效地促进河涌和湖泊水样中TN、COD_Cr和TP的去除.处理144h后,河涌水样初始浓度为11.15mg·L^-1、45mg·L^-1和1.17mg·L^-1的TN、COD_Cr和TP分别降至3.21mg·L^-1、15.8mg·L^-1和0.53mg·L^-1;湖水初始浓度为4.50mg·L^-1、36mg·L^-1和0.25mg·L^-1的TN、COD_Cr和TP分别降至2.31mg·L^-1、11.7mg·L^-1和0.03mg·L^-1.水样中的微生物和再力花均能去除NH₄⁺,并引起水中还原态氮发生亚硝化和硝化,但是不会明显改变Cl^-、SO₄^2-、Na⁺、K⁺、Mg²⁺和Ca²⁺等离子的浓度.     

黑曲霉RAF106菌丝球形成的影响因素及对结晶紫的吸附作用

【背景】黑曲霉（Aspergillus niger）作为一种代表性丝状真菌已被广泛用于酶制剂、有机酸、抗生素等高价值代谢产物的工业生产、食品发酵、环境治理等行业,其代谢能力、发酵性能等与菌体形态密切相关。然而,黑曲霉对染料、重金属等的吸附能力与菌体形态的关系鲜有报道。【目的】探究黑曲霉菌丝球形成的影响因素及其对结晶紫的吸附作用。【方法】以从普洱茶分离的黑曲霉RAF106为研究对象,实时监测马铃薯葡萄糖培养液中黑曲霉菌丝球的形成过程;探究培养液的初始pH （4.0-10.0）、培养温度（25-45°C）、孢子接种量（5×10⁴-5×10⁶个/m L）、摇床转速（140-220 r/min）、碳源（葡萄糖、蔗糖、果糖、乳糖、醋酸钠）和氮源（硝酸钠、胰蛋白胨、酵母提取粉、氯化铵）对菌丝球形成的影响;以结晶紫为对象,研究不同菌体形态及菌丝球大小对黑曲霉吸附废水染料能力的影响。【结果】在黑曲霉RAF106中,孢子聚集、菌丝聚集均可形成菌丝球;菌丝球的大小与培养液初始p H、孢子接种量成反比,与摇床转速无关;当温度低于35°C时,菌丝球大小与温度成正比,...     

皂化麦麸对锌的吸附性能

以麦麸制备生物吸附剂研究其对重金属Zn~(2+)的吸附作用。利用DPS软件进行回归正交试验,分析pH、麦麸生物吸附剂加入量、温度、初始Zn~(2+)浓度和吸附时间对吸附率影响,得出最佳吸附条件,与活性炭、麦麸纤维吸附效果作比较,对皂化麦麸进行解吸;同时研究等温吸附和吸附动力学,电镜和傅立叶红外光谱图研究吸附机理。吸附时间3 h、加入量0.2 g、pH值9、70℃、Zn~(2+)溶液浓度为80 mg/L时,吸附率达最大值,且低浓度时,麦麸生物吸附剂吸附效果优于活性炭与麦麸纤维,至少可以进行四次重复利用。麦麸生物吸附剂对Zn~(2+)吸附符合Freundich等温式,更适合拟二级动力学模型,即符合多分子层多位点物理化学混合吸附。SEM知皂化麦麸有明显褶皱,疏松多孔,表面积增大;FTIR分析出,麦麸生物吸附剂含-OH、-NH-、-C≡C-、-C≡N等多个官能团,对吸附过程起到很大的作用。     

再力花地下部水浸提液对几种水生植物幼苗的化感作用

采用砂培法研究了不同浓度再力花地下部水浸提液对荇菜、苦草、水田芥、芦苇和黄菖蒲幼苗的生长、光合速率、根系活力、叶绿素含量以及抗氧化保护酶活性的影响,并采用气相色谱-质谱(GC-MS)联用技术对再力花地下部水浸提液的化学成分进行了分析。结果表明:再力花地下部水浸提液对荇菜、苦草、水田芥、芦苇和黄菖蒲5种水生植物幼苗生长有明显的影响,其中使用50mg干重/mL再力花水浸提液处理5种水生植物幼苗,对其生长指标有着极显著的抑制作用(P<0.01),苦草、水田芥和黄菖蒲的净光合速率分别降低69.0%、63.7%和73.5%,荇菜、苦草、水田芥和黄菖蒲幼苗根系活力分别降低67.3%、65.4%、52.2%和46.7%,5种水生植物幼苗叶绿素含量分别下降59.7%、71.2%、35.2%、50.0%和76.5%。当处理浓度为5mg/mL时,对5种水生植物幼苗体内过氧化物酶(POD)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性有显著的促进作用;当浓度为50mg/mL时,对5种水生植物幼苗体内POD、SOD和CAT有显著的抑制作用,丙二醛(MDA)含量增加。分析显示,再力花地下部水浸提液中主要含有愈创木酚(78.93%)、邻苯二甲酸二丁基酯(7.13%)、邻苯二甲酸二乙氧基乙酯(1.48%)、香豆满(1.09%)、邻苯二甲酸二乙酯(0.98%)、松油醇(0.70%)、吲哚(0.65%)、二丁基羟基甲苯(0.64%),合计占到总量的91%以上。     

紫铆花素通过调节AMPK/GSK-3β信号通路抑制心肌缺血再灌注损伤

目的:研究紫铆花素对心肌缺血再灌注损伤的保护作用及其机制。方法:体外建立H9c2心肌细胞缺血再灌注模型,分为正常组、模型组、紫铆花素低、中和高剂量组(10,20和40μM)。检测细胞存活率,LDH释放水平,试剂盒检测MDA、SOD、IL-1和IL-6水平,蛋白印迹法检测Bax,Bcl-2蛋白的表达以及AMPK和GSK-3β磷酸化水平。结果:与模型组比较,紫铆花素能够提高细胞存活率,减少LDH水平,降低MDA、IL-1和IL-6,增加SOD水平。减少Bax,Caspase-3蛋白的表达,增加Bcl-2蛋白的表达,提高Bcl-2/Bax的比值(P0.05)。同时,紫铆花素能够剂量依赖性的促进AMPK和GSK-3β磷酸化。进一步研究发现,紫铆花素的保护作用以及对GSK-3β的促磷酸化被AMPK抑制剂Compound C抵消。结论:紫铆花素能减轻心肌缺血再灌注损伤,抑制心肌细胞凋亡,其作用机制可能通过激活AMPK/GSK-3β信号通路,减轻氧化应激水平有关。     

铅离子的生物吸附动力学及吸附热力学研究

目的：研究非活性深红酵母（Rhodotorula rubra）对重金属离子Pb^2＋的生物吸附热力学和动力学特性。方法：采用恒温摇床振荡吸附的实验方法,研究Pb^2＋生物吸附的动力学和热力学,并以适当的数学模型对实验数据进行拟合;对吸附前后的酵母进行红外光谱及X射线光电子能谱分析。结果：在20℃～45℃温度范围内,吸附5min时即达到了饱和吸附量的80%以上,2h左右达到平衡;深红酵母对Pb^2＋的生物吸附过程适宜用Elovich方程来描述;由二级动力学方程计算的生物吸附活化能为21.56kJ/mol;生物吸附平衡可用Langmuir等温式、Freundlich等温式及Dubinin-Radushkevich等温式来描述,拟合相关系数均接近0.99;Langmuir方程计算所得ΔH^0为13.93kJ/mol。结论：深红酵母对Pb^2＋的生物吸附是非均相的扩散过程,由快速吸附和慢速吸附两个阶段组成,以物理吸附为主,并伴随有化学吸附。     

大孔吸附树脂对金银花叶茎藤总黄酮的吸附性能

从金银花叶茎藤中提取总黄酮并用D-101大孔吸附树脂进行纯化,研究了D-101大孔吸附树脂对总黄酮的吸附及解吸附特性。结果表明,D-101树脂对金银花叶茎藤总黄酮分离纯化的最佳工艺参数为:上样液黄酮浓度0.538 mg/mL,静置吸附时间80 min,料液比1∶5(g∶mL),pH 2,流速为2 mL/min,以60 mL 75%的乙醇溶液洗脱,黄酮解吸率为94.5%,纯化后黄酮纯度为84.5%,是粗提液黄酮含量(16.8%)的5倍。金银花叶茎藤总黄酮在D-101树脂上的吸附等温线符合Langmuir等温吸附方程。吸附热力学参数表明吸附过程为自发、放热过程,吸附动力学可用Pseudo-second-order模型较好地拟合,30℃时其表观吸附速率常数为1.034×10-2g/mg.min。     

三氯蔗糖在大孔吸附树脂SP825上的吸附热动力学

采用静态吸附法,系统研究了三氯蔗糖在大孔吸附树脂SP825上的吸附热力学和动力学特性,为后续三氯蔗糖提取工艺的设计提供基础数据。实验结果表明:在283.15、293.15和303.15 K温度下,树脂SP825对三氯蔗糖的最大吸附量(每克湿树脂)分别为0.146、0.151和0.156 g。树脂SP825对三氯蔗糖的吸附平衡数据符合Lang-muir吸附等温方程,吸附过程为自发的物理吸附过程;并运用准二阶动力学模型描述了动力学过程,确定在实验条件范围内,吸附受颗粒内部传质速率的影响。     

In vitro cytotoxicity of Acanthamoeba spp. isolated from contact lens containers in Korea by crystal violet staining and LDH release assay

In order to observe the cytotoxicity of Acanthamoeba spp., which were isolated from contact lens containers as ethiological agents for the probable amoebic keratitis in Korea, the crystal violet staining method and LDH release assay were carried out. In the crystal violet staining method, among eight contact lens container isolates, isolate 3 (Acanthamoeba KA/LS5) showed 83.6% and 81.8% of cytotoxicity, and isolate 7 (Acanthamoeba KA/LS37) showed 28.2% and 25.1% of cytotoxicity, in 1 mg/ml and 0.5 mg/ml lysate treatments, respectively. Acanthamoeba culbertsoni and A. healyi showed 84.0% and 82.8% of cytotoxicity. Similar results were observed in A. castellanii and A. hatchetti which showed 83.6% and 75.5% of cytotoxicity. Acanthamoeba royreba and A. polyphaga showed 9.0% and 1.7% of cytotoxicity. In the LDH release assay, isolate 3 (20.4%) showed higher cytotoxicity than other isolates in 1 mg/ml lysate treatment. The results provide that at least isolate 3 has the cytotoxic effect against CHO cells and seems to be the pathogenic strain.     

A new rapid colourimetric method for testing Mycobacterium tuberculosis susceptibility to isoniazid and rifampicin: a crystal violet decolourisation assay

The aim of this study was to investigate the performance of a new and accurate method for the detection of isoniazid (INH) and rifampicin (RIF) resistance among Mycobacterium tuberculosis isolates using a crystal violet decolourisation assay (CVDA). Fifty-five M. tuberculosis isolates obtained from culture stocks stored at -80ºC were tested. After bacterial inoculation, the samples were incubated at 37ºC for seven days and 100 µL of CV (25 mg/L stock solution) was then added to the control and sample tubes. The tubes were incubated for an additional 24-48 h. CV (blue/purple) was decolourised in the presence of bacterial growth; thus, if CV lost its colour in a sample containing a drug, the tested isolate was reported as resistant. The sensitivity, specificity, positive predictive value, negative predictive value and agreement for INH were 92.5%, 96.4%, 96.1%, 93.1% and 94.5%, respectively, and 88.8%, 100%, 100%, 94.8% and 96.3%, respectively, for RIF. The results were obtained within eight-nine days. This study shows that CVDA is an effective method to detect M. tuberculosis resistance to INH and RIF in developing countries. This method is rapid, simple and inexpensive. Nonetheless, further studies are necessary before routine laboratory implementation.     

Microwave-assisted preparation and adsorption performance of activated carbon from biodiesel industry solid reside: influence of operational parameters

Preparation of activated carbon has been attempted using KOH as activating agent by microwave heating from biodiesel industry solid residue, oil palm empty fruit bunch (EFBAC). The significance of chemical impregnation ratio (IR), microwave power and activation time on the properties of activated carbon were investigated. The optimum condition has been identified at the IR of 1.0, microwave power of 600 W and activation time of 7 min. EFBAC was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and nitrogen adsorption isotherm. The surface chemistry was examined by zeta potential measurement, determination of surface acidity/basicity, while the adsorptive property was quantified using methylene blue as dye model compound. The optimum conditions resulted in activated carbon with a monolayer adsorption capacity of 395.30 mg/g and carbon yield of 73.78%, while the BET surface area and total pore volume were corresponding to 1372 m²/g and 0.76 cm³/g, respectively.     

Conformational change from antiparallel beta-sheet to alpha-helix in a series of depsipeptide, -(Leu-Leu-Lac)(n)-: syntheses, spectroscopic studies, and crystal structures of Boc-Leu-Lac-OEt and Boc-(Leu-Leu-Lac)(n)-OEt (n = 1, 2)

The depsipeptides Boc-Leu-Lac-OEt (1) and Boc-(Leu-Leu-Lac)(n)-OEt (n = 1, 2) (2 and 3, respectively) (Boc = tert-butyloxycarbonyl, Lac = L-lactic acid residue) has been synthesized and studied by crystallographic, CD spectroscopic, and ESI-MS analyses. In the packing cells, those three compounds adopt beta-strand conformations. Each molecule is linked into a dimer (1) or an infinite assembly (2 and 3) by tight hydrogen bonds of the type NH...O==C. Interestingly, the hexamer, 3 shows the first example of antiparallel pleated beta-sheet crystal structure for a depsipeptide molecule. In the packing cells, especially for 3, the ester groups O--C==O are perpendicularly oriented to the amide groups NH--C==O and beta-sheet planes to avoid the interaction between --O--(ester) and O==C. Therefore, when the chain length become longer, the O...O==C repulsion interaction works as a beta-sheet breaker and hence promotes an alpha-helical structure as observed for Boc-(Leu-Leu-Lac)(3)-Leu-Leu-OEt (4) (Oku et al. Biopolymers 2004, 75, 242-254) and Boc-(Leu-Leu-Lac)(n)-OEt (n = 4-6) (5-7) (Katakai et al., Biopolymers 1996, 38, 285-290), in which the O...O==C repulsion does not cause significant structural changes in alpha-helical main chains. Therefore from the structural and spectroscopic analyses, we have found governing factors for the specificity in the beta-sheet and alpha-helix decision in this series of depsipeptides, -(Leu-Leu-Lac)(n)-.