Modeling the yield of activated sludge in the presence of 2,4-dinitrophenol

In this work, a model was developed to evaluate the yield of activated sludge in the presence of 2,4-dinitrophenol (dNP). Experimental results show that the presence of dNP substantially reduced the sludge yield at all solid retention times tested, but that it had no negative effect on the bioactivity and settleability of activated sludge. With the established model, the maximum observed sludge yield (Y^′_max) and specific endogenous respiration rate (k_d) for the sludge without dNP dose were estimated as 0.79 g-MLSS/g-COD and 0.042 d⁻¹, respectively, whereas for the sludge dosed with dNP the corresponding values were calculated as 0.56 g-MLSS/g-COD and 0.056 d⁻¹, respectively. In the presence of dNP at 5 mg/l, the energy uncoupling coefficient was calculated as 0.29.     

利用荧光共振能量转移检测外源信号分子对拟南芥ATP水平的影响

本研究使用ATP特异性荧光共振能量转移(Fluorescence resonance energy transfer,FRET)为基础的荧光蛋白传感器(Ateam1.03-nD/nA),分析了4种外源信号分子(细胞外ATP、Ca²⁺、H₂O₂和NO)对拟南芥(Arabidopsis thaliana(L.)Heynh.)幼苗叶绿体和细胞质中ATP水平的影响。结果显示,细胞质ATP水平整体高于叶绿体,在4种不同浓度的信号分子处理下,叶绿体Ateam1.03-nD/nA的FRET比值仅在1.2 ~ 1.8波动;细胞质Ateam1.03-nD/nA 的FRET比值仅在2.2 ～ 3.0之间波动,未产生显著变化。结果表明在以上外源信号分子的作用下,植物细胞质和叶绿体ATP均维持在较为稳定的水平。     

Biological hydrogen production in a UASB reactor with granules. II: Reactor performance in 3-year operation

The experiment was conducted to evaluate the performance of an upflow anaerobic sludge blanket (UASB) with granules for H(2) production from a sucrose-rich synthetic wastewater at various substrate concentrations (5.33-28.07 g-COD/L) and hydraulic retention times (HRTs) (3-30 h) for over 3 years. The kinetics of H(2) production was evaluated, and the sludge yield and endogenous decay coefficient of the H(2)-producing granules were estimated to be 0.334 g-VSS/g-COD and 0.004/h, respectively. Based on Gibbs free energy calculations, the formation thermodynamics of caproate, an important aqueous product, were analyzed. Experimental results show that the H(2) partial pressure in biogas decreased with increasing substrate concentration, but was not sensitive to the variation of HRT in a range of 6-22 h. The H(2) production rate increased with increasing substrate concentration, but decreased with increasing HRT. The H(2) yield was in the range of 0.49-1.44 mol-H(2)/mol-glucose. Acetate, butyrate, caporate, and ethanol were the main aqueous products in the reactor, and their concentrations were dependent on both substrate concentration and HRT. An elevated substrate concentration resulted in a shift of fermentation from butyrate- to caporate-type in the reactor and the formation of caproate was dependent on the H(2) partial pressure. The 3-year experimental results demonstrate that H(2) could be produced continuously and stably from the acidogenic-granule-based UASB reactor.     

Quorum sensing unveils the sludge floccule-assisted stabilization of aerobic granules in granule-dominated sequencing batch reactors

Floccules are another major form of microbial aggregates in aerobic granular sludge systems. Previous studies mainly attributed the persistence of floccules to their relatively faster nutrient uptake and higher growth rate over aerobic granules; however, they failed to unravel the underlying mechanism of the long-term coexistence of these two aggregates. In this work, the existence and function of the floccules in an aerobic granule-dominated sequencing batch reactor were investigated from the view of quorum sensing (QS) and quorum quenching (QQ). The results showed that though the floccules were closely associated with the granules in terms of similar community structures (including the QS- and QQ-related ones), they exhibited a relatively higher QQ-related activity but a lower QS-related activity. A compatible proportion of floccules might be helpful to maintain the QS-related activity and keep the granules stable. In addition, the structure difference was demonstrated to diversify the QS- and QQ-related activities of the floccules and the aerobic granules. These findings could broaden our understanding of the interactions between the coexistent floccules and granules in aerobic granule-dominated systems and would be instructive for the development of the aerobic granular sludge process.     

Controlling pathogenic risks of water treatment biotechnologies at the source by genetic editing means

Antimicrobial-resistant pathogens in the environment and wastewater treatment systems, many of which are also important pollutant degraders and are difficult to control by traditional disinfection approaches, have become an unprecedented treat to ecological security and human health. Here, we propose the adoption of genetic editing techniques as a highly targeted, efficient and simple tool to control the risks of environmental pathogens at the source. An ‘all-in-one’ plasmid system was constructed in Aeromonas hydrophila to accurately identify and selectively inactivate multiple key virulence factor genes and antibiotic resistance genes via base editing, enabling significantly suppressed bacterial virulence and resistance without impairing their normal phenotype and pollutant-degradation functions. Its safe application for bioaugmented treatment of synthetic textile wastewater was also demonstrated. This genetic-editing technique may offer a promising solution to control the health risks of environmental microorganisms via targeted gene inactivation, thereby facilitating safer application of water treatment biotechnologies.     

数学形态学在昆虫分类学上的应用研究.Ⅰ.在目级阶元上的应用研究

根据昆虫图像,对半翅目（Hemiptera）、鳞翅目（Lepidoptera）、鞘翅目（Coleoptera）的34种昆虫提取形状参数、叶状性、球状性等7项数学形态特征进行了统计分析,从而论证了各项数学形态特征在目级昆虫分类阶元上作为分类特征的可行性和可靠性,并从数学形态学角度对所涉及到的同阶元昆虫类群的亲缘关系做了描述。结果表明,在作为目级阶元分类特征时,各项特征的可靠性依次为：(似圆度、偏心率、亮斑数)＞(叶状性、球状性、圆形性)＞形状参数。由这些特征的差异显著性可知,从数学形态特征角度讲,3个目的亲缘关系远近大小依次为：半翅目与鞘翅目＞半翅目与鳞翅目＞鳞翅目与鞘翅目。     

Studies on the Development of Male and Female Gametophytes in Sinojakia xylocarpa

Observed in this paper was the development of the microspore and megaspore, male and female gametophytes in Sinojakia xylocarpa, which is endemic to China. The anther comprises four microsporangia. Microspore wall forms simultaneously after meiotic division in PMCs. The arrangment of microspore in a tetrad is tetrahedral. Bicel lular pollen grains appear at the shedding stage. ‘They are 3-colporate, with irregular min ute-faveolate exine sculpture. The anther wall development is of the dicotyledonous type, and its endothecitum develops slight fibrous thickenings, which also form on some epidermal cells. The tapetum is glandular. The pistil with hollow style is composed of three carpels, and its ovary contains several anatropous ovules. The ovule is unitegmic, tenuinucellar, but no obturator was observed. The archesporial cell functions directly as the megaspore mother cell which forms a linear tetrad, but T-shaped tetrad was found in a few ovules. A Polygonum type embryo sac forms from the functional chalazal megaspore. In the mature embryo sac, the synergids are elongate with a large vacuole at the chalazal end, but the distrihution of vacuoles in the egg cell appears random. Two polar nuclei remain in contact with each other for a spell before the fertilization and the 3 antipodal cells may persist into early postfertilzation stages. Numerous starch gra ins occur in the embryo sac. According to the present embryological studies on Sinojakia xylocarpa and the works on embryogenesis by some early embryologist, authors consider that Styracaceae, Symplocaceae, Sapotaceae and Ebenaceae are rather closely related, and we alsoconsider it reasonable to put the 4 families mentioned above in Ebenales.     

Physicochemical characteristics of anaerobic H2-producing granular sludge

Granule-based biological H₂ production processes are gaining great popularity in recent years. An efficient and stable operating of such systems relies heavily on the performance of the H₂-producing granules (HPGs), which possess many unique properties compared with floc sludge and methanogenic granules. Hence, a full understanding of the sludge characteristics is essential. Especially, the physicochemical properties of HPGs may provide useful information for effective evaluation of system status. This review offers a systematical introduction of the physicochemical properties of HPGs, including size, morphology, settling velocity, permeability, rheology, surface charge, hydrophobicity and extracellular polymeric substances (EPS). We also analyze the relationships between these physicochemical factors and the system performance, and discuss the remaining challenges and future implications for sludge characterization and process monitoring. This work may facilitate a better understanding of granule-based biological H₂ production processes and offer a basis for timely process monitoring and manipulation.     

胞外三磷酸腺苷对铅胁迫下植物细胞损伤和过氧化氢及其清除酶水平的调节

细胞外三磷酸腺苷（extracellular adenosine-5'-triphosphate）是植物细胞的重要信号分子。以烟草悬浮细胞BY-2（Nicotiana tabacum L.cv.Bright Yellow-2）为材料,探讨了胞外三磷酸腺苷对铅胁迫下细胞损伤、H₂O₂（过氧化氢）含量及H₂O₂清除酶活性的影响。结果显示,随着Pb（NO₃）₂浓度的不断提高（30~400 μmol·L^-1）,细胞外三磷酸腺苷含量呈现出逐渐下降的趋势,但胞内三磷酸腺苷含量及细胞的受损伤程度逐渐增大;同时,H₂O₂含量和过氧化氢酶的活性均有所上升,并在200 μmol·L^-1 Pb（NO₃）₂处理下达到最大值,而过氧化物酶的活性则不断降低。较之Pb（NO₃）₂胁迫下的细胞,对Pb（NO₃）₂胁迫的细胞加入外源三磷酸腺苷使得细胞受损伤程度显著降低,H₂O₂含量减少,过氧化氢酶活性减弱,而过氧化物酶活性增强。实验结果表明,Pb（NO₃）₂胁迫诱导的植物细胞损伤和H₂O₂及其清除酶水平的变化能受到细胞外三磷酸腺苷水平的调节。     

大齿山芹根的精油成分

大齿山芹根的精油成分薛怡琛,鲜启鸣,张涵庆（江苏省植物研究所,中国科学院植物研究所,南京２１００１４）关键词伞形科;大齿山芹;精油ＣｈｅｍｉｃａｌｃｏｎｓｔｉｔｕｅｎｔｓｏｆｔｈｅｅｓｓｅｎｔｉａｌｏｉｌｆｒｏｍｔｈｅｒｏｏｔｏｆＯｓｔｅｒｉｃｕｍｇ...