金属矿区芒草脯安酸积累的一个有趣现象(英文)

植物的脯安酸含量与其对环境的耐受性有很大的关系。通过采集金属矿区(主要污染物为Zn、Cu、Pb、Cd)不同污染梯度、不同季节的芒草种群材料,测定其脯安酸含量,从脯安酸角度探讨受不同污染强度胁迫的种群的耐性变化。结果发现:①夏季芒草种群的脯安酸含量随土壤重金属含量的升高而升高,与体内Cu积累量呈显著的正相关关系;②冬季脯安酸含量呈现相反的趋势,即重度污染土壤的种群脯安酸含量降到最低,而受轻度污染样地的种群与清洁种群一样,脯安酸含量升到最高;③受中度污染种群的脯安酸含量变化与清洁种群相似。这一结果说明重度的重金属污染已引起芒草种群在脯安酸水平发生代谢变化,意味着这一芒草种群可能已获得较强的环境耐性,但这一猜测还有待于进一步研究。

采用垃圾准好氧填埋消除酸积累现象的试验研究

针对垃圾厌氧填埋渗滤液在直接回灌初期会出现严重的酸积累现象,分析研究了垃圾准好氧填埋与厌氧填埋的渗滤液直接回灌后的出水水质,发现采用准好氧垃圾填埋的体系内所含挥发性脂肪酸量和COD量比厌氧填埋柱低得多,不存在酸积累现象;从整个降解过程看,准好氧填埋加快了COD的降解速率,加速了垃圾体的稳定化进程;另外,环境温度对垃圾体的降解速率影响很大,较高的温度能够加速垃圾体的降解速度。

酸转运蛋白与果实酸积累关系的研究进展

苹果酸和柠檬酸是大多数成熟果实中酸度形成的主要贡献者。有机酸从细胞质进入液泡贮藏是一个复杂的过程,高度依赖大量的有机酸转运体和各种质子泵基因。本文重点综述了近年来园艺作物果实中有机酸积累与有机酸转运基因之间关系的研究进展,并对未来的研究方向提出了建议。

温度及有机负荷对高温高含固污泥厌氧消化启动期产甲烷特性影响研究

高含固热水解-高温厌氧消化工艺可有效提升城镇污水处理厂污泥厌氧消化负荷和能量利用率。当不同污泥厌氧消化工艺切换至高含固热水解-高温厌氧消化时,由于受到高氨氮、高温及高负荷的影响,易引发酸积累。为探讨不同工艺启动高温高含固率厌氧消化工艺的可行性,本研究使用稳定运行的中温常规含固率R1反应器[(35±1)℃,总固体(TS)含量为2%]、中温高含固率R2反应器[(35±1)℃,TS含量为10%]、高温常规含固率R3反应器[(55±1)℃,TS含量为2%]和中温高含固率R4反应器[(35±1)℃,TS含量为14%],并以高含固率(10%)热水解剩余污泥为基质开展高温高含固率厌氧消化反应器启动试验,分析启动过程中氢代谢速率、比产甲烷活性以及微生物群落结构变化,并探讨温度、含固率对产甲烷特性的影响。结果表明:由4种不同工况反应器启动高温高含固率反应器后,各组反应器的挥发性固体降解率为39.8%~41.6%,保持了较高的产甲烷性能。乙酸产甲烷活性相较于启动前下降了37.9%~73.4%,但氢利用速率从0.585~4.914 kPa/(g·h)增至6.76~18.25 kPa/(g·h)。氢营养型产甲烷菌Methanothermobacter和Methanoculleus成为高温高氨氮环境下的优势菌种,启动后其相对丰度提至57.84%~83.94%。高温常规含固率厌氧消化反应器在工况切换前初始氢利用速率达到4.914kPa/(g·h),表现出较高的稳定性。因此,由高温常规含固率反应器启动切换至高温高含固厌氧消化工艺是一种可行策略,关键是提升启动期的初始氢利用速率。

苹果果实中苹果酸代谢关键酶与苹果酸和可溶性糖积累的关系

以‘东光’ב富士’苹果杂交后代为试材,研究苹果果实中苹果酸代谢关键酶与苹果酸和可溶性糖积累的关系。结果表明,负责苹果酸合成的磷酸烯醇式丙酮酸羧化酶(PEPC)、细胞质NAD依赖的苹果酸脱氢酶(cyMDH)和负责苹果酸跨膜运输的H+-焦磷酸酶(VHP)在高、低酸苹果果实成熟过程中活性没有明显差异,而负责苹果酸跨膜运输的H+-ATPase酶(VHA)在高酸果实中有较高的活性,负责苹果酸降解的细胞质NADP依赖的苹果酸酶(cyME)和ATP依赖的磷酸烯醇式丙酮酸羧化激酶(PEP-CK)则在低酸果实中有较高的活性。还从苹果酸向可溶性糖转化的角度探讨了苹果酸代谢关键酶对可溶性糖积累的影响。

立式连续干发酵装置的设计与产气特性

该研究设计的立式连续干发酵装置的几点特色包括搅拌升温调节罐、多点分布式进料、立式连续干发酵反应器和熟料回流混合过程,形成一种高固体浓度有机废弃物制取生物燃气的工艺方法及其发酵系统,可实现沼气工程的快速启动、厌氧发酵罐内无需搅拌、且节能,节水,减少沼液沼渣的排放量,保护环境,降低成本。采用上述设计的反应器进行发酵试验,研究熟料回流对产气特性的影响得出,应用回流的各组挥发性脂肪酸(volatile fatty acids,VFA)都有所降低,且回流比为1:7的VFA含量最低,氨氮没有累积,C/N接近25,产气效果最好。回流比1:9组,VFA含量累积最高,同时出现氨氮抑制产气的现象,所以得出熟料回流量过多,厌氧发酵系统就会受到抑制,且熟料回流对沼气中甲烷含量没有显著影响。

Citric Acid Accumulation in an Alkali_tolerant Plant Puccinellia tenuiflora Under Alkaline Stress

The accumulation of citric acid and associated correlative strain indexes were investigated in the seedlings of Puccinellia tenuiflora (Griseb.) Scribn. et Merr. stressed with 0-175 mmol/L Na 2CO 3. The results showed that the citric acid accumulation is a specific physiological respond of this plant to alkali_stress. On the contrary, the citric acid content decreased slightly in this plant stressed with 0-400 mmol/L neutral salt NaCl. The accumulation of citric acid increased with increasing strength of alkali_stress, the citric acid content increased gently when the strength was lower than 100 mmol/L Na 2CO 3, but increased obviously when the strength was higher than 100 mmol/L Na 2CO 3. The citric acid rapidly accumulated at early alkali_stress, an obvious raise can be mensurated after 4 h. About 48 h after treatment, the amount of citric acid accumulated nearly reached the maximum. In various parts of P. tenuiflora seedlings alkali_stressed for 144 h, the order of citric acid content from high to low is: old leaf, mature leaf, old leaf sheath, young leaf sheath, young stem, old stem, and young leaf. In the mature leaf, the citric acid content gradually increased with increasing strength of alkali_stress, while the citric acid content increased sharply in old leaf and sheath just for strength higher than 125 mmol/L. There was little change of citric acid content in stem, but no change in young leaf. The results of the experiment showed that citric acid was outstanding among accumulated organic acid caused by alkali_stress. The contribution of other organic acids was negligible.

草鱼肠道离体培养的适宜条件

取 1龄草鱼 (体长 2 0～ 2 5cm)肠道制成常规肠囊样本 ,分别使用Ringer’s液、山本液、今村液以及 1mmol/L亮氨酸 (Leu)溶液和 1uci/mlH3-Leu溶液进行体外培养 ,并设定培养条件分别为 :培养温度 2 0、2 5、30和 37℃ ,培养时间 5、10、30及 6 0min。测定在各条件下草鱼肠道碱性磷酸酶 (AKP)活性和Leu的吸收积累量。结果显示 ,1龄草鱼肠道离体培养最佳条件为 :培养液为山本液 (NaCl 0 .75 % ,KCl 0 .0 2 % ,Ca Cl2 0 .0 2 % ,NaHCO30 .0 0 2 % ) ,培养时间为 5min ,培养温度为 2 5℃。此时 ,草鱼肠道AKP活性为 5 1.6 1金氏单位 ,对Leu的吸收速率为 0 .0 4 72 μmol/ (g·min)。

Protective Effects of Glycinebetaine on Brassica chinensis Under Salt Stress

Brassica chinensis L. were foliarly applied with glycinebetaine (GB), as this species is unable to synthesis GB and sensitive to osmotic stress such as salt. The exogenous GB was easily absorbed and transported by the leaf of B. chinensis . Its application (0-20 mmol/L) enhanced the plant tolerance to salt stress. The treatment of 15 mmol/L GB significantly decreased the Na + accumulation in leaf and root under NaCl stress. This difference in accumulating Na + and K + is caused by higher selectivity of root absorption. Furthermore, GB increased H +_ATPase activity of root plasma membrane evidently. This result strongly suggested that in root the decreased Na + accumulation was caused by the GB accumulation that enhanced the extrusion of Na + from the cell in some way through plasma membrane transporter, e.g. Na +/H + antiport driven by H +_ATPase. The GB application was also found to stabilize the plasma membrane, to decrease the loss of chlorophyll, and to stimulate the osmosis induced proline response under salt stress.

特殊饮料──温开水

特殊饮料──温开水温开水，是新鲜开水凉至２０至２５度的［白开水］，它具有的某些特异生理活性，是许多高级饮料无法比拟的。美国生理学家博士约翰发现，温开水比较容易透过细胞膜，促进新陈代谢，增加血液中血红蛋白含量，因而有利于改善人的免疫功能。习惯喝温开水，...

Effects of Amino Acids Replacing Nitrate on Growth,Nitrate Accumulation,and Macroelement Concentrations in Pak-choi (Brassica chinensis L.)

A hydroponic experiment was carried out to determine the influence of replacing 20% of nitrate-N in nutrient solutions with 20 individual amino acids on growth, nitrate accumulation, and concentrations of nitrogen （N）, phosphorus （P）, and potassium （K） in pak-choi （Brassica chinensis L.） shoots. When 20% of nitrate-N was replaced with arginine （Arg） compared to the full nitrate treatment, pak-choi shoot fresh and dry weights increased significantly （P ≤ 0.05）, but when 20% of nitrate-N was replaced with alanine （Ala）, valine （Val）, leucine （Leu）, isoleucine （Ile）, proline （Pro）, phenylalanine （Phe）, methionine （Met）, aspartic acid （Asp）, glutamic acid （Glu）, lysine （Lys）, glycine （Gly）, serine （Ser）, threonine （Thr）, cysteine （Cys）, and tyrosine （Tyr）, shoot fresh and dry weights decreased significantly （P ≤ 0.05）. After replacing 20% of nitrate-N with asparagine （Asn） and glutamine （Gin）, shoot fresh and dry weights were unaffected. Compared to the full nitrate treatment, amino acid replacement treatments, except for Cys, Gly, histidine （His）, and Arg, significantly reduced （P ≤0.05） nitrate concentrations in plant shoots. Except for Cys, Leu, Pro, and Met, total N concentrations in plant tissues of the other amino acid treatments significantly increased （P ≤ 0.05）. Amino acids also affected total P and K concentrations, but the effects differed depending on individual amino acids. To improve pak-choi shoot quality, Gln and Asn, due to their insignificant effects on pak-choi growth, their significant reduction in nitrate concentrations, and their increase in macroelement content in plants, may be used to partially replace nitrate-N.

Nitrite Accumulation during the Denitrification Process in SBR for the Treatment of Pre-treated Landfill Leachate

The nitrite accumulation in the denitrification process is investigated with sequencing batch reactor （SBR） treating pre-treated landfill leachate in anoxic/anaerobic up-flow anaerobic sludge bed I（UASB）. Nitrite accumulates obviously at different initial nitrate concentrations （64.9,54.8,49.3 and 29.5 mg·L^-1 ） and low temperatures, and the two break points on the oxidation-reduction potential （ORP） profile indicate the completion of nitrate and nitrite reduction. Usually, the nitrate reduction rate is used as the sole parameter to characterize the denitrification rate, and nitrite is not even measured. For accuracy, the total oxidized nitrogen （nitrate ＋ nitrite） is used as a measure, though details characterizing the process may be overlooked. Additionally, batch tests are conducted to investigate the effects of C/N ratios and types of carbon sources on the nitrite accumulation during the denitrification. It is observed that carbon source is sufficient for the reduction of nitrate to nitrite, but for further reduction of nitrite to nitrogen gas, is deficient when C/N is below the theoretical critical level of 3.75 based on the stoichiometry of denitrification. Five carbon sources used in this work, except for glucose, may cause the nitrite accumulation. From experimental results and cited literature, it is concluded that Alcaligene species may be contained in the SBR activated-sludge system.

Effect of Sludge Retention Time on Nitrite Accumulation in Real-time Control Biological Nitrogen Removal Sequencing Batch Reactor

In this study,four sequencing batch reactors(SBR),with the sludge retention time(SRT)of 5,10,20 and 40 d,were used to treat domestic wastewater,and the effect of SRT on nitrite accumulation in the biological nitrogen removal SBR was investigated.The real-time control strategy based on online parameters,such as pH,dissolved oxygen(DO)and oxidation reduction potential(ORP),was used to regulate the nitrite accumulation in SBR. The model-based simulation and experimental results showed that with the increase of SRT,longer time was needed to achieve high level of nitritation.In addition,the nitrite accumulation rate(NAR)was higher when the SRT was relatively shorter during a 112-day operation.When the SRT was 5 d,the system was unstable with the mixed liquor suspended solids(MLSS)decreased day after day.When the SRT was 40 d,the nitrification process was significantly inhibited.SRT of 10 to 20 d was more suitable in this study.The real-time control strategy combined with SRT control in SBR is an effective method for biological nitrogen removal via nitrite from wastewater.

Cloning and nucleotide sequence of D-hydantoinase gene of marine polyphosphate-accumulating bacterium, Halomonas sp. YSR-3

Hydantoinase is involved in the production of optically pure amino acids from racemic 5-mono-substituted hydantoins. We measured the D-hydantoinase activity in marine Halomonas sp. YSR-3 and amplified the D-hydantoinase gene by PCR. The gene was inserted into vector pGM-T and transformed into E. coli TOP10. The positive transformants with the D-hydantoinase gene were sequenced. The sequenced fragment comprises 1 510 base pairs. The D-hydantoinase gene from YSR-3 is 77% similar to that from Pseudomonas entornophila L4 by searching against the NCBI databse. The protein product of the YSR-3 D-hydantoinase gene is 75%, 73%, and 70% similar to those from Pseudomonasfluorescens Pf-5, Marinornonas sp. MED121, and Burkholderia vietnamiensis G4, respectively. The difference of the D-hydantoinase gene between marine Halornonas sp. YSR-3 and other terrestrial organisms is distinct.

Effect of Salinity Stress on Capsicum annuum Callus Growth, Regeneration and Callus Content of Capsaicin, Phenylalanine, Proline and Ascorbic Acid

The present research was conducted to study salinity effect on callus growth and regeneration from the local Chilli pepper cultivar as well as calli content of capsaicin, phenylalanine, proline and ascorbic acid. The results showed that the Pericarp gave the highest fresh and dry weight of 511.6 mg and 56.95 mg respectively at 9 dSm-1 compared with other interactions. Moreover the lowest fresh and dry weight was recorded for the root calli grown at 12 dSm-1. The highest regeneration percentage was 87.20% at 3 dSm-1 and the lowest was 6.70% at 9 dSm-1. For explant effect on regeneration, the highest percentage was 71.1% for shoot tips and the lowest was 23.30 % from the pericarp. However no plants were regenerated at 12 dSm-1 from all explants and at 9 dSm-1 from calli induced from roots, placenta and pericarps. Calli induced from Pericarp contain significantly higher Proline amount at 12 dSm-1 which was 34.65 μg/g and the lowest was 2.57 μg/g at 3 dSml. Moreover Phenylalanine ranged from 28.23 μg/g at 3 dSml and 41.50μg/g at 12 dSm1. While a wide range between the explants in the Ascorbic acid amount was recorded. The highest was 47.21 μg/g from the Placenta calli and the lowest was 0.98 μg/g from the Shoot tip calli. On the other hand calli produced from Placenta gave the highest amount of Capsaicin 53.11 μg/g at 9 dSm-1 which was not significantly different than the placenta and the pericarp at 12 dSml and the shoot tips, placenta and the pericarp at 9 μg/g. In conclusion Chili pepper callus tolerated salinity via the accumulation of Ascorbic acid, Proline, Phenylalanine and Capsaicin. Moreover Chili Pepper grown In vitro under salt stress contained high amount of Capsaicin the important pharmaceutical compound. Finally pepper plants were regenerated from salt stressed calli might be salt tolerant under field conditions.

Salt Stress Effects on Germination, Plant Growth and Accumulation of Metabolites in Five Leguminous Plants

The investigation was conducted to determine physiological criteria of early selection for salt tolerant leguminous plants. Plants were subjected to 5 levels of salt stress at the roots （0, 50, 100,150 and 200 mM NaCI）. Results showed that sodium chloride had an underrating effect on growth of stems and seed germination of the species studied. The germination rates of seeds of Glycine max and Phaseolus vulgaris （sensitive glyeophytes） were affected from 3 g/L of NaCl, with critical thresholds at 9 and 12 g/L respectively. In contrast, critical thresholds with Mucunapoggei （facultative halophyte）, Vigna unguiculata （moderately tolerant glycophyte） and P. adenanthus （natural halophyte） was found to be above 21 g/L. The reduction of stems growth rate were not significant in P. adenanthus whereas in M. poggei and V. unguiculata this inhibition was observed just when nutritive solutions were enriched with 200 mM. The lipid contents were reduced in all the species under salt stress, whereas proteins and proline contents in the leaves were substantially increased in tolerant species （M. poggei, P. adenanthus and V. unguiculata）. In contrast, proteins and leaf proline contents were negatively affected by salt concentration to G. max and P. vulgaris. Seed germination, proteins and proline could be used as physiological criteria of early selection for salt tolerant leguminous plants.

Storage and Subsequent Reactivation of Phosphate-Accumulating Aerobic Granules

Phosphate-accumulating aerobic granules cultivated in a sequencing batch reactor were composed of inner rod-shaped bacteria aggregates and outer twining filamentous bacteria. The influence of two-month storage under dif- ferent conditions on the storage and subsequent reactivation performance of aerobic granules was investigated. After two-month storage the granules sealed at 4 ~C in distilled water or normal saline （named granules A and granules B, respectively） could maintain their characteristics as before, while the granules idled in the reactor at room temperature （named granules C） exhibited decreased properties. During reactivation, granules A and granules B presented almost identical recovery performance, faster than granules C, in terms of phosphorus removal efficiency, mixed liquor sus- pended solids （MLSS）, phosphate release and accumulating ability. The results suggest that hermetical storage at low temperature promoted the maintenance of the granular properties and the reviving behaviors of phosphateaccumulating aerobic granules, and storage medium had little influence on the storage and recovery perfomlance.

Cloning and Characterization of a Lycium chinense Carotenoid Isomerase Gene Enhancing Carotenoid Accumulation in Transgenic Tobacco

Carotenoid isomerase （CRTISO）is a key enzyme that catalyzes the conversion of cis-lycopene to all- trans tycopene. In this study, we isolated and characterized the CRTISO gene from Lycium chinense （LcCRTISO） for the first time. The open reading flame of LcCRTISO was 1 815 bp encoding a protein of 604 amino acids with a molecular mass of 66.24 kDa. Amino acid sequence analysis revealed that the LcCRTISO had a high level of simi- larity to other CRTISO. Phylogenetic analysis displayed that LcCRTISO kept a closer relationship with the CRTISO of plants than with those of other species. Semi-quantitative PCR analysis indicated that LcCRTISO gene was expressed in all tissues tested with the highest expression in maturing fruits. The overexpression of LcCRTISO gene in transgenic tobacco resulted in an increase of total carotenoids in the leaves with [3-carotene and lutein being the predominants. The results obtained here clearly suggested that the LcCRTISO gene was a promising candidate for carotenoid production.

Variation in Rubisco and other photosynthetic parameters in the life cycle of Haematococcus pluvialis

Cells of Haematococcus pluvialis Flot. et Will were collected in four different growth phases. We quantified the initial and total enzyme activity of ribulose-1,5-bisphosphate carboxylase （Rubiseo） in crude extracts, and the relative expression of large-subunit ribulose-1,5-bisphosphate caboxylase / oxygenase （rbcL） mRNA. We measured the ratio of photosynthetic rate to respiration rate （P/R）, maximal effective quantum yield of photosystem II （Fv/Fm）, electron transport rate （ETR）, actual photochemical efficiency of PSI1 in the light （ФPSII）, and non-photochemical quenching （NPQ）. Green vegetative cells were found to be in the most active state, with a relatively higher P/R ratio. These cells also displayed the lowest NPQ and the highest Fv/Fm, ETR, and ФPSII, indicating the most effective PSII. However, both Rubisco activity and rbcL mRNA expression were the lowest measured. In orange resting cysts with relatively lower P/R and NPQ, Rubisco activity and rbcL expression reached a peak, while Fv/Fm, ETR, and ФPSII were the lowest measured. Taking into account the methods of astaxanthin induction used in industry, we suggest that Rubisco may participate in astaxanthin accumulation in H. pluvialis. A continuous and sufficient supply of a carbon source such as CO2 may therefore aid the large scale production of astaxanthin.