[Microbial Diversity of Filamentous Sludge Bulking at Low Temperature].

To investigate the characteristics of microbial diversity during filamentous bulking at low temperature, the induction of sludge bulking was successfully carried out using a low-temperature sequencing batch reactor(SBR). With the help of Illumina MiSeq high-throughput sequencing technology, the overall changes in the microbial community structure of activated sludge, the characteristics of each specific microbial community, and the specific genera were all investigated under different sludge sedimentation performances. The results showed that filamentous bulking can be successfully induced after the system operating temperature drops to (14±1)℃, and the COD and TN removal rates can still be maintained at approximately 90% and 86%, respectively, with the sludge volume index deteriorating to 663.99 mL·g-1. The occurrence of sludge bulking at low temperature will not only reduce the overall diversity and uniformity of microorganisms in the system and increase the abundance of filamentous bacteria from 0.49% to 26.04% but also cause the abundance of denitrifying bacteria to reduce from 21.04% to 13.99% and that of dephosphorization bacteria to reduce from 4.25% to 1.93%. Of the five filamentous genera founded, the abundances of three filamentous bacteria represented by Thiothrix increased, whereas only that of the Haliscomenobacter decreased. Of the 19 denitrifier genera founded, the abundances of five species represented by Nitrosomonas increased, whereas those of seven species represented by Nitrospira decreased. Moreover, the abundances of Pseudomonas and Tetrasphaera increased out of the eight phosphorus-removing bacteria genera, whereas the abundances of the five bacteria genera represented by Candidatus_Competibacter decreased. Although sludge bulking has a significant impact on the structure of the microbial community, the 477 operational taxonomic units and 227 bacterial species that are always present in the different sludge samples indicate that the main microorganisms in the reactor are still relatively stable during the bulking process.

Gas/particle partitioning, particle-size distribution of atmospheric polybrominated diphenyl ethers in southeast Shanghai rural area and size-resolved predicting model.

A size-segregated gas/particle partitioning coefficient KPi was proposed and evaluated in the predicting models on the basis of atmospheric polybrominated diphenyl ether (PBDE) field data comparing with the bulk coefficient KP. Results revealed that the characteristics of atmospheric PBDEs in southeast Shanghai rural area were generally consistent with previous investigations, suggesting that this investigation was representative to the present pollution status of atmospheric PBDEs. KPi was generally greater than bulk KP, indicating an overestimate of TSP (the mass concentration of total suspended particles) in the expression of bulk KP. In predicting models, KPi led to a significant shift in regression lines as compared to KP, thus it should be more cautious to investigate sorption mechanisms using the regression lines. The differences between the performances of KPi and KP were helpful to explain some phenomenon in predicting investigations, such as PL0 and KOA models overestimate the particle fractions of PBDEs and the models work better at high temperature than at low temperature. Our findings are important because they enabled an insight into the influence of particle size on predicting models.

Occurrences, composition profiles and source identifications of polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in ship ballast sediments.

The aim of this study was to investigate the levels of persistent organic pollutants (POPs) including polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in ship ballast sediments. The ballast sediment samples were collected from six merchant ships docked in 2015 in Jiangyin City, China. Ballast sediments represent a potential vector for the transport of POPs and invasive species between marine environments. An attempt was also made to determine the sources of these compounds in the ballast sediment. The results indicated ballast sediments generally contain greater amounts of BDE-209 and comparable amounts of PAHs, PBDEs (exclusive of BDE-209) and PCBs compared to those in marine surface sediments. Based on the sediment quality guidelines, PAHs and PCBs in ballast sediments were estimated to have median or high potential of posing ecological risks, respectively, to marine life if ballast sediments were disposed without specific treatment. POPs in ballast sediments were derived from multiple sources with atmospheric deposition being an important origin. Ship activities including diesel exhaust and illegal oil sewage discharge were considerable contributors of certain individual POPs to ballast sediments. Our study is important because it represents the first report on levels, health risk assessment and source apportionments of POPs in ballast sediments and is a first step in the implementation of specific ballast sediment management measures.

Laboratory study of the particle-size distribution of Decabromodiphenyl ether (BDE-209) in ambient air.

Laboratory measurements for particle-size distribution of Decabromodiphenyl ether (BDE-209) were performed in a 0.5 m(3) sealed room at 25 °C. BDE-209 was manually bounded to ambient particles. An electrostatic field-sampler was employed to collect particles. The number of collected particles (n(i,j), i and j was the class of particle diameter and applied voltage on electrostatic field-sampler sampler, respectively) and the corresponding mass of BDE-209 in collected particles (m(∑i,j)) were determined in a series of 6 experiments. The particle-size distribution coefficient (ki) was calculated through equations related to n(i,j) and m(∑i,j), and the particle-size distribution of BDE-209 was determined by ki·n(i,j). Results revealed that BDE-209 distributed in particles of all size and were not affiliated with fine particles as in field measurements. The particle size-fraction should be taken into account when discussing the particle-size distribution of BDE-209 in ambient air due to the normalized coefficients (normalized to k1) and were approximately in the same order of magnitude for each diameter class. The method described in the present study was deemed feasible in determining the particle-size distribution of BDE-209 from vaporization sources and helpful to understanding the instinct rule of particle-size distribution of BDE-209, and potentially feasible for other SVOCs.

[The generation of H2O2 in wheat hypersensitive reaction induced by leaf rust fungus].

H2O2 burst in the defense responses of Wheat (Triticum aestivum L.) infected with compatible and incompatible leaf rust fungus races (Puccinia recondita f.sp. tritici) was investigated firstly. Cytofluorimetric analysis using the fluorescent probe DCFHDA scrutinized the generation of H2O2 in wheat primary leaves. The results indicated that H2O2 burst could be induced by either compatible or incompatible leaf rust fungus. However, the kinetics of H2O2 burst in incompatible interaction were biphasic, and the peak of phase II (20h after inoculation) was much higher than that of phase I (12h after inoculation), whereas, there only existed the weak and transient phase I H2O2 accumulation at 12h after inoculation in compatible interactions. In addition, pharmacological experiments were carried out. Antioxidants (AsA, DTT) and inhibitors of the mammalian neutrophil NADPH oxidase (DPI, imidazole) were separately injected into wheat primary leaves before inoculation to study their effects on hypersensitive reaction (HR) and H2O2 production in incompatible interaction. It was observed that treatments of wheat leaves with AsA, DTT, DPI or imidazole obviously suppressed the two peaks of intracellular H2O2 burst, whereas the second peak was inhibited much more. Moreover, the area of hypersensitively dead cells was decreased in the four treatments. These results suggested that NADPH oxidase may play an important role in H2O2 generation during wheat-leaf rust fungus interaction, and H2O2 burst may be involved in HR caused by leaf rust invading.

[Ultracytochemical localization of enzymes and DNA analysis during the development of garlic].

It is believed that during storage, the parenchyma cells of garlic (Allium sativum L.) bulb would wither and fade gradually, and nutrients released inside the cells become available for the germination and growth of the young bud. In this study, The distributions of acid phosphatase (APase) and Adenosine Triphosphatase (ATPase) during germination were analyzed based on the method of lead precipitation at the electron microscopic level. It was found that their activities presenting in plasma membrane, cell wall and plasmodesma increased along the different developmental periods during storage. The fact that the most intensive enzymatic activity of APase and ATPase appeared at germination indicates that degradation, transformation and exportation of cell matrix are helpful in complete translocation of nutrient to new bud. The DNA in the degrading parenchyma cells was analyzed using the agarose electrophoresis. Results clearly showed a typical DNA ladder on the gel, indicating that gene-controlled, programmed cell death may contribute to the degradation of garlic parenchyma cells.

[Histological observation on programmed cell death in wheat-leaf rust fungus intreaction].

The biochemical character of PCD in different interaction between wheat and Puccinia recondita f. sp tritici was observed using DNA agarose gel electrophoresis and end labeling in situ (Terminal Deoxynucleotidyl Transferase-mediated dUTP Nick End TUNEL). The DNA ladder, which is the typical character of programmed cell death(PCD), was observed in incompatible combination (cv.lorvin10 x race 162) and the positive reaction in wheat leaves of incompatible combination since 12h after inoculation also appeared. The results, coupled with the previous study, indicated that HR was a typical form of PCD in incompatible combination between wheat and wheat leaf fungus.

[Studies on the change of intercellular connection and the appearance and function of ectodesmata-like structure in garlic clove during the dormancy development].

The characteristics of intercellular connection have been observed during the dormancy development of garlic by the transmission electron microscope (TEM). The results indicated that the appearances of the different states of intercellular connection were physiological adaptation to the development of garlic clove during storage. Ectodesmata-like existed at the wall boundary between the declining tissue and the living cells in the garlic during germination period. By Confocal Laser Scanning Microscopy (CLSM) combined with fluorescence probe, 457Da Lucifer Yellow (LYCH) which was impermeable to the membrane, could enter the living parenchyma cell through symplastic route. The result proved that ectodesmata-like structure, which may be recognized as the modified plasmodesata, still retained physiological activity during a certain time and function as the channels of the symplastic transport of nutrient.

[Histological observation on programmed cell death in wheat--leaf rust fungus intreactioin].

The ultrastructural features of mesophyll cell surrounding the fungus in different interaction between wheat and Puccinia recondita f. sp tritici were observed with transmission electron microscopy. In incompatible combination(cv. lorvin 10 x race 162), the nuclei gradually became irregular with highly condensed chromatin towards the nuclear envelope, while the chloroplast became swelling since 12 h to 24 h after inoculation(a.i.). At 48 h a.i., the condensation of the chromatin became more prominent and the chloroplast began to disintegrate. Finally, when some mitochondria started to degrade at 72 h a.i., the nuclei and the chloroplast became disruption completely. During the process, endoplasmic reticulum and vesicles did play a vital role in the further degeneration of other organelles and protoplasmic components just similar to the lysosome acting in the animal cells. These results suggest that the ultrastructural feature of cell death is a form of programmed cell death (PCD). In compatible combination (cv. lorvin 10 x race 165), ultrastructural of mesophyll cell exhibited different features from incompatible combination. At 24 h a.i., the plasmic membrane showed sunken and the chloroplast slightly exhibited swelling. Since 48 h to 72 h a.i., most of the swelling chloroplasts were observed while the other organelles still remained unaltered. At the same time, the hypha and haustorium mother cell in the intracellular space also could be observed.