Size exclusion chromatography for the removal of pigments from extracellular ligninolytic enzyme extracts from decayed wheat straw

Solid-state fermentation of wheat straw was carried out by a native white rot basidiomycete Daedaleopsis flavida strain 5A. Extract prepared from the 12-day decayed wheat straw contained extracellular ligninolytic enzymes like manganese peroxidase (MnP), manganese-independent peroxidase (MIP), lignin peroxidase (LiP) and laccase along with straw-degraded products and pigments. Sephacryl S-200 size exclusion chromatography in 16/100 column was used for the separation of these ligninolytic enzymes and straw-degraded products and pigments. Recovery of pigment-free ligninolytic enzyme activities as protein was 40% of the total proteins loaded and specific LiP activity increased 34 fold after size exclusion chromatography. Thus accurate estimation of LiP by veratryl alcohol oxidation assay was possible only after the removal of interfering pigments. The reproducibility of size exclusion chromatography is adjudged satisfactory from the consistent results obtained after seven repetitive uses of matrices.     

Effect of surfactants on Fenton's reagent-mediated degradation of Kraft black liquor

One of the limitations of the biodegradation of hydrophobic chemical compounds, like lignins, is their low solubility in the aqueous solution where this process takes place. To resolve this problem, surfactants have been used to improve the solubility of these hydrophobic compounds. In this investigation, we studied the effect of surfactants (anionic, cationic, and non-ionic) on the treatment of Kraft black liquor with Fenton's reagent. In the Fenton reaction, H2O2 (two different concentrations, 10 mM and 20 mM), FeCl2 (1 mM) and surfactant solution (10%) were used. Black liquor degradation was determined by UV/Visible spectrophotometry and by measuring phenolic groups. In the presence of Fenton's reagent, the optimum conditions for the oxidative degradation of black liquor were 10 mM H2O2, 1 microL of 10% solution of anionic surfactant (SDS). The importance of the use of surfactants for preparing black liquor for subsequent Fenton's reagent-mediated degradation was discussed.     

Chromatophorotropic neurohormones of the shrimp Crangon crangon. Partial purification of the red-pigment-concentrating hormone

Three chromatophorotropic neurohormones, present in the aqueous extract of acetone-dried and powdered eyestalk of the shrimp Crangon crangon (L.), were separated by gel filtration on a Sephadex G-25 column in 0.1 M acetic acid containing 1 mM mercaptoethanol (Fig. 1). Gel filtration was performed in a cold room at 4°C. The red-pigment-concentrating hormone, after gel filtration on Sephadex G-25 column, was pooled and freeze-dried. The increase in total activity of red-pigment-concentrating hormone after gel filtration through Sephadex G-25 as compared with the total activity of this hormone in aqueous extract (Table 1) was caused by removal of black-pigment-dispersing hormone. Purification of red-pigment-concentrating hormone was achieved by repeated gel filtration on a Sephadex G-15 column. Red-pigment-concentrating hormone appeared as a symmetrical peak (the fourth peak in Fig. 3) when the absorbance of effluent was measured at 235 nm. Red-pigment-concentrating-hormone purified on Sephadex G-15 column has a specific activity about 9000 times greater than in the initial material.     

Amelioration of arsenic toxicity by phosphate salts in mungbean seedlings

Sodium arsenate (Na2HAsO4.7H2O) is a potent inhibitor of mungbean seed germination and seedling growth. Germination is totally stopped at or above 50 microM Na2HAsO4.7H2O. Inhibition of seedling elongation started at a lower concentration of 5 microM As(V) and was drastically reduced at 20 microM As(V). Nutrients like salts of macroelements viz., NaH2PO4.2H2O, KH2PO4, K2SO4, MgSO4.7H2O, CaCl2.2H2O, (NH4)2SO4 NH4NO3 solutions at a concentration of 10mM and microelements viz., ZnSO4, CuSO4.5H2O, Na2MoO4.2H2O, MnCl2.4H2O, CoCl2.6H2O, FeSO4.7H2O solutions at a concentration of 1mM could help to ameliorate the toxic effects of As(V) to different degrees. Amelioration of As(V) toxicity was possible only when the mungbean seeds were pretreated with the above mentioned nutrients for 24 hr and then transferred to sodium arsenate. Simultaneous treatment of nutrients with As(V) or using nutrient solutions following As(V) treatment were of no help to reverse the toxic effects of sodium arsenate.     

Isoperoxidases show differing sensitivity to salicylic acid

The effects of salicylic acid (SA) on the activity of total peroxidase and the patterns of isoperoxidases of cultured tobacco cells were investigated. The total peroxidase activity of tobacco cells was inhibited by 70% when the cells were treated with 5 mM SA for one week. The peroxidase activity of tobacco cells is declined by 90% in the presence of 30 mM SA. Moreover, the activity of isoperoxidases C3, A1, and A3 decreased dramatically with increasing SA concentration, while, one of the anodic isoperoxidases, A2, was somewhat resistant to SA treatment. When isoperoxidase C3 was isolated, SA inhibited the activity of purified C3 in a concentration-dependent manner. The IC50 of isoperoxidase C3 was approximately 0.45 mM. However, the inhibition of isoperoxidase C3 activity was removed by the addition of Fe2+ ion. The possible mechanism of inhibition of peroxidase by SA is discussed.     

螺孢菌ZG9901的筛选及其产碱性果胶酶发酵条件研究

用筛选培养基从芦苇土壤中筛选到７株碱性果胶酶产生菌株,经初筛选和复筛得到产酶活性较高的一株菌株ＺＧ９９０１,初步鉴定为螺孢菌属Ｓｐｉｒｉｌｌｏｓｐｏｒａ ｓｐｐ．最适摇瓶产酶条件是：果胶２０ｇ／Ｌ,乳糖２０ｇ／Ｌ,蛋白胨３ｇ／Ｌ,酵母膏４ｇ／Ｌ,ＫＨ２ＰＯ４１ｇ／Ｌ,ＭｇＳＯ４．７Ｈ２Ｏ０．０４ｇ／Ｌ,ＭｇＣｌ２０．２ｇ／Ｌ,ｐＨ９．０,３２℃培养３６ｈ达到产酶高峰。     

Regulation of fructose-2,6-bisphosphate content in mantle tissue of the sea musselMytilus galloprovincialis

6-phosphofructo-2-kinase (PFK-2) from the mantle of the sea musselMytilus galloprovincialis Lmk, collected from the Ría de Arosa (NW Spain) in 1990, was purified 550-fold by extraction and sequential affinity chromatography on Affi-gel Blue and ATP-agarose columns. The enzyme was a dimer with a native molecular weight of 100 kilodaltons (KDa) and a subunitM _r of 53 KDa. PFK-2 activity is dependent on the presence of P_i. At physiological P_i concentrations, the enzyme exhibits hyperbolic kinetics with both ATP and Fru-6-P, withK _m values of 0.62 and 0.37 mM respectively. In vivo, PFK-2 activity is limited by the concentration of Fru-6-P which is low in comparison with theK _m for this substrate. Citrate and PEP inhibited PFK-2 activity.     

La(NO3)3浸种对盐碱胁迫下红小豆幼苗生长和抗氧化酶活性的影响

采用添加NaCl和Na2CO3模拟盐胁迫和碱胁迫的水培方式,研究了La(NO3),浸种对盐胁迫和碱胁迫下红小豆幼苗生长和抗氧化酶活性的影响.结果表明:(1)与无胁迫对照组相比,盐碱胁迫明显抑制了红小豆幼苗的生长;在Na+质量浓度相同的情况下,碱胁迫对红小豆幼苗生长的影响明显大于盐胁迫;(2)使用La(NO3)3浸种可缓解盐碱胁迫带来的不良影响,使受胁迫红小豆的株高、叶面积、总根长、总根数、叶绿素、根活力、SOD活性、POD活性及CAT活性增加,并显著降低幼苗MDA含量水平,且表现出在盐碱胁迫下变化幅度高于无胁迫处理的现象;(3)在本试验条件下,30 mg·L-1La(NO3)3浸种具有显著促进红小豆根系及地上部分生长的作用.     

Salt stress induced alteration in growth characteristics of a grass Pennisetum alopecuroides

Salinity is one of the major abiotic stresses that adversely affect crop productivity and quality. The present investigation was carried out to study the alterations in the growth characteristics of a grass species, Pennisetum alopecuroides under the influence of sodium chloride (NaCl) salinity. From the results it is clear that shoot length of Pennisetum alopecuroides was increased by 13.17% at 100 mM NaCl concentration while the root length was observed to be increased at 50 mM NaCI concentration by 26.93%.Maximum height of the plant was observed by 18.23% at 50 mM while shoot to root ratio was higher at 300 mM concentrations by 29.17% increase over the control. Moreover, the maximum percent increase in leaf area was recorded as 11.17% (100 mM). Fresh weight was increased by 50.92% at 100 mM while dry weight of the experimental grass was increased by 33.64% at the same concentration of salt to the rooting medium while moisture percentage was increased to a maximum by 24.61% at 50 mM. It appears that the grass species studied exhibit a moderate salinity tolerance as far as linear growth of plant is concerned.     

有害因子胁迫对人支气管上皮细胞SO2生物合成的影响

为了探讨有害因子胁迫与二氧化硫(SO2)细胞生物合成的关系,采用体外培养实验方法研究了不同浓度H2O2(0.1、1、10mmol·L-1)以及不同pH值(6.8、7.2、8.0)培养液对人支气管上皮细胞(BEP2D)SO2产生量(以胞内SO32-含量代表)的影响.结果表明:1)培养液过酸(pH6.8)和过碱(pH8.0)均可使BEP2D细胞SO2产生量显著增加(与对照相比,p<0.05);2)H2O2胁迫也可使BEP2D细胞SO2产生量增加,当H2O2浓度≥1mmol·L-1时,与对照相比,差异达到显著(p<0.05).以上结果提示:人支气管上皮细胞在有害因子的胁迫下可产生内源性SO2;SO2可能是一种生物气体应激分子,能像应激蛋白那样提高生物体对有害因子的抵御能力.     

盐胁迫条件下三角滨藜叶片中盐分的积累与分配

用扫描电镜和能谱仪测定不同浓度NaCl胁迫2wk后的三角滨藜幼叶和成熟叶中Na 在细胞外和细胞内的分布情况,并利用原子吸收分光光度计测定叶片中Na 的积累量,同时还观测了盐囊泡及其与盐的积累、分泌之间的关系.结果表明,在盐胁迫下,三角滨藜叶片中的Na 积累量随根外溶液盐浓度的升高而增加,而盐囊泡的含盐量并无显著变化.同时发现,叶片中的Na 主要积累在细胞内.因此,可以认为,三角滨藜主要靠吸收并在细胞内积累Na 来降低渗透势,保证植株的水分吸收,而三角滨藜的盐囊泡在盐分分泌与抗盐中并无实质性作用.图2表3参12     

培养条件对产酸克雷伯氏菌SG-11生物合成IAA影响的研究

研究了产酸克雷伯氏菌（Ｋｌｅｂｉｓｅｌｌａ ｏｘｙｔｏｃａ）ＳＧ－１１菌株的培养条件对其ＩＡＡ生物合成的影响。结果表明：该菌生长到稳定期时才开始大量产生ＩＡＡ;在基本培养基中,该菌对不同氮源的利用有别,在以（ＮＨ４）２ＳＯ４为氮源时,ＩＡＡ的产量最高,作为碳源的葡萄糖当加入浓度为６ｇ／Ｌ时,游离态ＩＡＡ的产量最高;在ＬＢ培养基中,当ｐ（Ｏ２）由正常值降低１／４时,ＩＡＡ的产生量陡然下降,灭菌前,把     

纳米氧化铜(CuO NPs)对紫花苜蓿幼苗根系活性氧(ROS)、抗氧化酶活性和根系活力的影响

根系通常是植物直接受到外界环境物质(如重金属离子和纳米金属氧化物)毒害的主要器官。本研究以紫花苜蓿的幼苗为实验材料,探讨了CuO NPs胁迫对紫花苜蓿幼苗根系的活性氧(ROS)积累、抗氧化酶活性和根系活力的影响。研究结果表明:(1)不同浓度的CuO NPs对紫花苜蓿幼苗根系H_2O_2和O-2·含量具有显著影响。随CuO NPs浓度增大,紫花苜蓿幼苗根系中H_2O_2和O-2·整体上呈现先增大后减少的趋势,除了0.00125 mol·L~(-1)CuO NPs浓度下紫花苜蓿幼苗根系中H_2O_2含量比对照减少外,其他浓度下的H_2O_2和O-2·的含量都比对照有所增加,并且H_2O_2和O-2·的含量都是在0.0125 mol·L~(-1)CuO NPs浓度下达到最大值。(2)不同浓度的CuO NPs对紫花苜蓿幼苗根系抗氧化酶活性具有显著影响。随CuO NPs浓度增大,紫花苜蓿幼苗根系中SOD、POD、APX和CAT酶的活性都呈现先增大后减少的趋势,其中,SOD和POD、APX、CAT酶的活性分别是在0.00625、0.0125、0.0625 mol·L~(-1)CuO NPs处理下达到最大,表明这些抗氧化酶在清除根系中的活性氧方面表现出较强的协同性和补偿性。(3)不同浓度的CuO NPs对紫花苜蓿幼苗根系活力具有显著的影响。随着CuO NPs浓度的增加,紫花苜蓿幼苗根系活力逐步升高,这是一种生物适应性应激响应的体现。     

Composition of the proteinaceous gel secretion from the skin of the Arabian Gulf catfish (Arius thallasinus)

The Arabian Gulf catfish Arius thallasinus excretes copious amounts of proteinaceous gel from epidermal cells when threatened or injured. As a means of investigating its biological role, this gel material has been examined to determine the nature of the secretion and its associated biological activities. Over 85% of the dry weight of the gel material is protein with small amounts of lipids, carbohydrates and nucleic acid components. Most of the protein exists as a high molecular weight aggregate of predominantly 13 500 molecular weight monomeric units. Several lytic enzyme activities are found in the gel secretion, one of which catalyzes lysis of red blood cells. Other factors induce clotting in citrate treated plasma and agglutination of red blood cells. The enzymic properties of the gel secretion resemble those of some animal venoms.     

Seed pre-soaking with 24-epibrassinolide reduces the imidacloprid pesticide residues in green pods of Brassica juncea L.

The effect of 24-epibrassinolide seed soaking on imidacloprid residues in green pods and mature seeds of Brassica juncea L. plants was investigated. The activities of the antioxidative enzymes glutathione-S-transferase, glutathione peroxidase, glutathione reductase, ascorbate peroxidase and guaiacol peroxidase, and the content of glutathione were determined. Imidacloprid residues in green pods were analyzed and quantified by gas chromatography-mass spectrometry, revealing that 24-epibrassinolide treatment resulted in a decrease of residues by almost 30%. In mature seeds, no pesticide residues were detected. Activities of all the antioxidative enzymes and glutathione content were found to be high in plants grown in soil amended with 300 mg imidacloprid kg^?1 soil, but pre-soaking with 100 nmol L^?1 24-epibrassinolide further enhanced the activities of all these enzymes and the glutathione content.     

Intervention research on influence of biomass briquette on human health

Raw coal (RC) is the main fuel in many, especially rural parts of China. Biomass briquette (BB), which has less SO₂ emission, was developed as a cleaner alternative for RC. In this research, the cooking fuel of a group of countrywomen was switched from RC to BB and studied for health effects. Five biological indices percent of comet cell (COMET), lysozyme saliva (LYS), malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX) were chosen. All indices were measured three times during the 18-month experiment. Statistical analysis shows that there are significant changes in the indices. Using BB as a cooking fuel improves the function of anti-oxidation system and the nonspecific immune system, and reduces the DNA damage, which is negatively related to LYS and SOD.     

The influence of suspension density and temperature on the filtration rate of Hiatella arctica

The rate of filtering Phaeodactylum tricornutum and Isochrysis galbana was measured in Hiatella arctica (L.) by the indirect suspension depletion method monitored by optical density measurement. The filtration rate of H. arctica was found to be 1.412×10^–2 l/h/g wet weight at a temperature of 15°C when fed with P. tricornutum, at average cell concentrations up to 3.5×10⁶ cells/ml. The filtration rate dropped almost to zero when the concentration of P. tricornutum reached 11×10⁶ cells/ml. The filtration rate of I. galbana diminished at a much lower cell concentration of 1×10⁶ cells/ml, and almost ceased at 3 to 4×10⁶ cells/ml. In mixed cultures of I. galbana and P. tricornutum, the filtration rate ratio was 0.37 to 1.00, and this was believed to be due to a proportion of the smaller former cells passing through the ostia. However, when resuspended in sea water, I. galbana cells were taken at a rate slightly less than P. tricornutum. The medium in which the I. galbana cells had been grown was inhibitory to the filtering activity of H. arctica, since, when cells of either alga were resuspended in the medium, the filtration rate was considerably reduced. No inhibitory factor existed in either of the original nutrient media. Hence, the importance of using low cell concentrations and of eliminating any inhibitory metabolic products when measuring filtration rates of bivalves is stressed. H. arctica shows a typical activity temperature eurve for a boreo-arctic species, with a steady rise from 0°C to a maximum between 15° and 17°C, and a sharp fall in activity to about zero at 25°C. The rates of filtration of various species at temperatures approaching the optimum were compared after allowance was made for fall in filtration rate with increasing body weight. The results suggested that the Mytilacea had the highest filtration rates and that H. arctica possesses one of the lowest filtration rates recorded.     

纳米氧化锌对羊角月牙藻毒性效应及其在藻细胞内外的分布

为研究纳米氧化锌(ZnO NP)的毒性效应及其在细胞内外分布,以羊角月牙藻(Selenastrum capricornutum)为模型藻类,研究了不同浓度ZnO NP对羊角月牙藻生长、叶绿素含量、可溶性蛋白含量、超氧化物岐化酶(SOD)及过氧化物酶(POD)活性、丙二醛(MDA)含量及细胞内外ZnO NP含量变化。结果表明,ZnO NP对羊角月牙藻的生长抑制与处理浓度呈现正相关。在45 mg·L~(-1)ZnO NP暴露24 h后,其生长抑制率已达到95%。当ZnO NP处理藻细胞72 h后,羊角月牙藻细胞的叶绿素含量与处理浓度之间存在剂量-效应关系。低浓度(0.5 mg·L~(-1))ZnO NP处理后藻细胞可溶性蛋白质含量、SOD和POD活性明显下降,MDA含量升高,其产生的毒性效应高于高浓度组(5 mg·L~(-1)、45 mg·L~(-1))。细胞培养液溶出Zn2+量及藻细胞外吸附的ZnO NP量与ZnO NP处理浓度成正比,但是藻细胞内ZnO NP量与ZnO NP浓度没有相关性,胞内积累量基本维持不变。研究表明,各浓度组对藻细胞毒性的差异,不仅与细胞内Zn2+量有关,还与细胞外粘附的ZnO NP有关。     

Antioxidant enzymes in the digestive gland of the common musselMytilus edulis

Antioxidant enzymes function to remove deleterious reactive oxygen species, including the superoxide anion radical and H₂O₂. Subcellular distributions and optimal and other properties of catalase (EC. 1.11.1.6), superoxide dismutase (SOD; EC. 1.15.1.1), selenium-dependent glutathione peroxidase (Se-GPX; EC. 1.11.1.9) and total glutathione peroxidase (GPX) activities were determined in the digestive gland of the common musselMytilus edulis L. by spectrophotometric and cytochemical/electron microscopic (catalase) techniques. Assay conditions for Se-GPX and total GPX activities were determined which optimized the difference between the non-enzymic and enzymic rates of reaction. General peroxidase activity (guaiacol as substrate) (EC. 1.11.1.7) was not detectable in any subcellular fraction. Catalase was largely, if not totally, peroxisomal, whereas SOD and GPX activities were mainly cytosolic. Distinct mitochondrial (Mn-SOD) and cytosolic (CuZn-SOD) SOD forms were indicated. Catalase properties were consistent with a catalase, rather than a catalase-peroxidase. The pH-dependence and temperature-dependence of GPX activity were different with H₂O₂ or CHP as substrate, and these and other observations indicate the existence of a distinct Se-GPX. Under saturating or optimal (GPX) assay conditions, the apparent Michaelis constantsK _m (mM) were: catalase, 48 to 68 (substrate, H₂O₂); Se-GPX, 0.11 (H₂O₂) and 2.0 (glutathione); and total GPX, 2.2 (eumene hydroperoxide) and 1.2 (glutathione). Calculated catalase activity was 2 to 4 orders of magnitude greater than Se-GPX activity over an [H₂O₂] of 1 to 1000 M. The results are discussed in relation to theoretical calculations of in vivo oxyradical production and phylogenetic differences in antioxidant enzyme activities.     

邻苯二甲酸二丁酯的酶促降解性的研究

测定了Ｐｓｅｕｄｏｍｏｎａｓ ｆｌｕｏｒｅｓｃｅｎｓ ＦＳ１的邻苯二甲酸酯降解酶对邻苯二甲酸二丁酯的降解特性;提出了邻苯二甲酸二丁酯酶促降解的途径,Ｐｓｅｕｄｏｍｏｎａｓ ｆｌｕｏｒｅｓｃｅｎｓ ＦＳ１细胞中的颗粒部分、溶液部分对邻苯二甲酸二丁酯都具有降解作用,Ｐｓｅｕｄｏｍｏｎａｓ ｆｌｕｏｒｅｓｃｅｎｓ ＦＳ１的邻苯二甲酸酯降解酶尾胞内酶;Ｐｓｅｕｄｏｍｏｎａｓ ｆｌｕｏｒｅｓｃｅｎｓ ＦＳ１