Quantitative source apportionment of dissolved organic matters in wet weather overflows of storm drainage systems based on degradation potential index and end member mixing model.

Dissolved organic matter (DOM) in wet weather overflows (WWFs) of storm drainage systems mainly originates from anthropogenic sources, such as paved runoff, illegally discharged domestic sewage and the retained sediment. This study provides a promising method to quantitatively apportion the WWF DOM of storm drainage systems using degradation potential index (DPI) and end member mixing (EMM) model. DPI is derived from excitation-emission matrix parallel factor analysis (EEM-PARAFAC), which can endow the end members and itself of WWF DOM with numerical features, and thus help quantify the source contributions of WWF DOM in EMM model. Findings show that (1) DPI was a reliable tool in the quantitative source apportionment of WWF DOM, owing to its features of small variance within source and large variances between sources; (2) DPI combined with EMM model could help identify the factors that induce significant impacts on the source contributions of WWF DOM, such as the storm pumping discharge and antecedent dry days in our case study; (3) the identified factors could guide the development of effective strategies for WWF DOM control, e.g. sediment management in our case.

In vitro digestion and fecal fermentation of highly resistant starch rice and its effect on the gut microbiota.

Highly resistant starch rice (HRSR) is of particular interest in terms of its capacity to deliver short-chain fatty acids (SCFAs) to the colon in the prevention of diabetes mellitus and obesity. In this study, HRSR was processed into cooked rice, rice milk, rice cake, and rice popcorn, and the in vitro digestion and fermentation processes were monitored. The results showed that the starch digestibility of the four samples conformed to a first-order two-phase equation, and the resistant starch content of rice cake was the highest (11.98%). Compared with inulin, rice cake had a slower fermentation rate, and the butyrate concentration increased by 67.85%. The abundances of Prevotellaceae, which promotes the synthesis of SCFAs, and anti-inflammatory Faecalibacterium increased. The abundances of Proteobacteria and Megamonas, markers of gut microbiota imbalance, decreased. The results might facilitate the design and production of functional food products for type 2 diabetic and obese patients and improving colonic health.

Complexing characteristics between Cu(â ¡) ions and dissolved organic matter in combined sewer overflows: Implications for the removal of heavy metals by enhanced coagulation.

Enhanced coagulation has been widely used in storm tanks to remove heavy metal ions (HMs) from combined sewer overflows (CSOs), but faces challenges on removing the HMs bound to dissolved organic matter (DOM) with small molecular weight (MW). DOM ubiquitously existing in CSOs generally contains a large distribution range of MW, which can significantly impact the MW distribution of HMs by complexing reaction, thereby adding uncertainties for the removal efficiency of coagulation. Therefore, realizing the potential MW distribution of the HMs bound to CSO-DOM is greatly important for cost-effectively removing HMs from CSOs in the coagulation process. This paper presents a comprehensive approach of ultrafiltration, fluorescence quenching titration, excitation-emission matrix parallel factor analysis, complexation model, and two-dimensional correlation fluorescence spectroscopy for exploring the MW-based complexing characteristics between Cu(II) ions and CSO-DOM components. Results show that: (1) Cu(II) ions that bound to the CSO-DOM were mainly distributed in the MW range of <5 kDa, which makes them very difficult to be removed from CSOs by coagulation technique. (2) Concentration effect and molecular composition exerted great impacts on the MW distribution of the Cu(II) ions bound to CSO-DOM. (3) The humic-like component of terrestrial origin with the MW range of 100 kDa∼0.45 µm possessed high binding stability, capacity, and priority with Cu(II) ions, and they could be used at a high concentration to promote the removal efficiency of coagulation for Cu(Ⅱ) ions of CSOs by competitive complexation and inter-molecular bridging.

[Start-up Performance of Low-substrate Anaerobic Ammonium Oxidation Under Different COD Concentrations].

An anaerobic sequencing batch reactor(ASBR)was used to treat low-substrate simulated wastewater with NH4+-N and NO2--N concentrations of (25.00±0.40) mg·L-1 and (33.00±0.60) mg·L-1, respectively. The COD concentrations were controlled at 5.00, 15.00, 30.00, and 50.00 mg·L-1 by adding sodium acetate, and its effects on start-up of anaerobic ammonia oxidation (ANAMMOX) were investigated under the temperature of 30℃. The results showed that ① The start-up of ANAMMOX could be achieved successfully after 74, 94, 106, and 129 days. The nitrogen removal efficiency was optimum when the COD concentration was between 15.00 and 30.00 mg·L-1. In the steady phase, the average effluent concentrations of NH4+-N were 1.98 and 1.89 mg·L-1, the average effluent concentrations of NO2--N were below 0.62 mg·L-1, and the average effluent concentrations of TN were 2.37 and 2.28 mg·L-1. ② The average contribution of heterotrophic denitrification to nitrogen removal decreased to 4.78%, 9.59%, 10.21%, and 36.50%, respectively, during start-up process. The average contribution of ANAMMOX to nitrogen removal gradually increased to 95.22%, 90.41%, 89.79%, and 63.50%, respectively. ③ The activities of ANAMMOX exceeded denitrification activities at 44, 76, 86, and 114 days, respectively, which finally reached 0.700, 0.690, 0.670, and 0.510 mg·(g·h)-1, and the denitrification activities were 0.110, 0.130, 0.240 and 0.410 mg·(g·h)-1, respectively. Thus, the research results have provided references for the application of ANAMMOX to engineering.

[Simultaneous Nitrification and Denitrifying Phosphorus Removal in Continuous Flow Reactor with Intermittent Aeration].

A continuous flow reactor (TCFR) with 10 compartments was used to treat domestic sewage. The anaerobic compartments of TCFR were kept at 3. The anoxic compartments of TCFR were reduced from 2 to 0. Therefore, the aerobic compartments of TCFR were increased gradually from 5 to 7. The aerobic compartments were set to continual aeration in Run1 and intermittent aeration from Run2 to Run4. The aeration/non-aeration ratios were 40 min/20 min,40 min/30 min, and 40 min/40 min, respectively. The nitrification liquid reflux ratios were reduced gradually from 150% to 0%. When the average influent concentrations of COD, NH4+-N, TN, and PO43--P were 259.34, 60.26, 64.42, and 6.10 mg·L-1, respectively, the corresponding effluent concentrations were 26.40, 1.03, 5.84, and 0.3 mg·L-1, respectively in Run4. The nitrogen removal amounts increased gradually from 192.30 mg·h-1 in Run1 to 244.00 mg·h-1 in Run4, and the corresponding removal rates increased from 65.40% to 95.30%. The activity of denitrifying phosphorus accumulating organisms (DPAOs) and phosphorus accumulating organisms (PAOs) increased from 36.05% and 38.20% in Run1 to 140.50% and 133.40% in Run4, respectively. Simultaneous nitrification and denitrifying phosphorus removal was achieved in TCFR by adopting intermittent aeration, which provided a reference for the reformation of sewage treatment plants.

Evaluation of the MiSeq FGx system for use in forensic casework.

Capillary electrophoresis (CE) is widely used in forensic genetics to study short tandem repeats (STRs). Recently, next-generation sequencing (NGS) platforms have facilitated the development of new strategies for forensic DNA typing. Several studies have shown that NGS successfully analyzes challenging samples. However, because NGS is complicated and time-consuming, it remains unclear whether NGS platforms offer significant advantages over CE for all forensic cases. Here, the MiSeq FGx system was used to test some cases that had previously been analyzed using CE. These cases included paternity test cases in which some samples exhibited locus inconsistencies; samples with off-ladder (OL) alleles; samples with triallelic patterns; and samples with amelogenin test abnormalities. The results generated by MiSeq FGx were compared to those previously generated by CE. The MiSeq FGx and CE results were consistent with the exception of three samples, where inconsistencies were observed at the Penta D locus. For all three incongruent samples, the MiSeq FGx results were correct. Sequence analysis indicated that, in two cases, mismatches were due to undetected alleles rather than mutations. In two additional cases, mutation sources were identified, and in a fifth case, mutation step size was reconsidered. MiSeq FGx was used to identify OL alleles and samples with amelogenin test abnormalities. For cases where verification was required via CE analysis, the simultaneous NGS amplification of several types of multiple genetic markers improved testing efficiency. In addition, we identified additional sequence variants at autosomal, Y chromosomal, and X chromosomal STR loci in the Han Chinese population from northern China. Our results will be useful for future forensic analyses of STR genotypes in Chinese populations. It is likely that NGS would be more widely used in forensic genetics if costs and procedure complexity were reduced.

[Characteristics of Denitrifying Phosphorus Removal by A2/O-BAF at Low Temperatures].

Low C/N domestic sewage was treated by an A2/O-biological aerated filter (BAF) system at low temperatures (11-14℃). The characteristics of pollutant removal, the ratio of denitrifying phosphorus to nitrogen (ΔPO43-/ΔNO3-N) and effects of aeration flow and effective packing height on nitrification in BAF were studied. The results showed that when the average influent concentrations of COD, NH4+-N, TN and PO43- were 193.1, 58.6, 60.3 and 5.1 mg·L-1 respectively, their effluent concentrations were 46.3, 2.5, 13.4 and 0.3 mg·L-1 respectively, which met the first level A criteria specified in the discharge standard of pollutants for municipal wastewater treatment plant (GB 18918-2002). The linear fitting of ΔPO43-/ΔNO3--N was between 0.47 and 1.75. The normal distribution of mathematical statistics was applied-and the average standard deviation for ΔPO43-/ΔNO3--N were 1.20 and 0.29 respectively. When the aeration flows were 60 L·h-1 and 100 L·h-1, the effluent concentration of NH4+-N was less than 5.0 mg·L-1, corresponding to the effective packing heights in the BAF of 1.8 m and 1.0 m respectively. However, when the aeration flow was increased to 120 L·h-1, the air-water flow led to biofilm detachment, which caused the effluent concentration of NH4+-N to increase beyond 5.0 mg·L-1.

[Effect of HRT on Nitrogen Removal Using ANAMMOX and Heterotrophic Denitrification].

Real domestic sewage was first treated in SBR and partial nitrification was achieved. When average concentrations of NH4+-N, NO2--N, and COD were 37.27, 39.97, and 120 mg·L-1, respectively, the effluent was delivered as influent of an anaerobic ammonia oxidation reactor (ASBR). The effect of different HRTs (36 h, 33 h, 30 h, 27 h) on nitrogen removal of ANAMMOX and heterotrophic denitrification were investigated under conditions of temperature of 24℃ and pH of 7.2±0.2. Results showed that 1 nitrogen removal efficiency was optimum with HRT of 33 h. The average total nitrogen load rate(TNLR)and total nitrogen removal rate(TNRR)were 0.056 kg·(m3·d)-1and 0.050 kg·(m3·d)-1, respectively. The average effluent concentrations of NH4+-N, NO2--N, and COD were 1.36, 0.47, and 49.79 mg·L-1, and removal rates were 96.30%, 98.83%, and 56.17%, respectively. △NO2--N/△NH4+-N and △NO3--N/△NH4+-N were 1.17 and 0.15, 0.15 and 0.11 less than theoretical ANAMMOX values (1.32, 0.26) due to heterotrophic denitrification. 2 The contribution of ANAMMOX to nitrogen removal decreased; however, the contribution of heterotrophic denitrification to nitrogen removal gradually increased with decreasing HRT. This provides a point of reference for ANAMMOX in engineering applications.

[Effect of Step Feed on Denitrifying Phosphorus and Nitrate Removal in a Modification of the Two Sludge A2/O-BAF System].

A modification of the two sludge A2/O-BAF system was used to treat low C/N real domestic sewage. In order to improve the utilization of the carbon source, the effects of two step feeds (pre-anoxic zone and anoxic zone) on denitrifying phosphorus and nitrate removal were studied. According to the formula of material balance for COD, the utilization of carbon source was analyzed and evaluated under different ratios of step feed, simultaneously. The results showed that when the ratio of step feed was 7:3 and the influent concentrations of COD, NH4+-N, TN, and TP were 174.99, 58.19, 59.10, and 5.15 mg·L-1, respectively, their effluent concentrations were 29.48, 4.07, 14.10, and 0.40 mg·L-1, and the removal rates were 82.12%, 92.76%, 75.45%, and 91.20%, respectively. It was found that when the ratio of the denitrifying phosphorus accumulation organisms to the phosphorus accumulation organisms(DPAOs/PAOs) was 98.81%, the efficiencies of denitrifying phosphorus and nitrate removal were optimum. By optimizing step feed, the carbon source was utilized effectively, and the efficiencies of nitrogen and phosphorus removal were improved simultaneously. The theoretical basis has thus been provided for the modification of the two sludge A2/O-BAF system to treat low C/N waste water.

[Performance of the Removal of Nitrogen During Anaerobic Ammonia Oxidation Using Different Operational Strategies].

The effects of low substrate ratio, cooling methods, and pH on nitrogen removal performance were studied in a laboratory-scale anaerobic ammonium oxidation reactor (ASBR) while treating simulated domestic waste water. The results illustrated that the average removal efficiencies of NH4+-N and NO2--N increased from 54.4% and 65.3% to 95.8% and 92.5%, respectively, at a temperature of 30℃ and an influent concentration of NO2--N of (30±0.2)mg·L-1. The substrate ratio (NO2--N/NH4+-N) increased from 0.9 to 1.4.However, the removal efficiency of NH4+-N was affected negligibly, and the average removal efficiency of NO2--N decreased to 54.6% when the substrate ratio was increased to 1.6, suggesting that the nitrogen removal performance of anaerobic ammonium oxidation was best when the substrate ratio was close to the theoretical value of 1.32.The average removal efficiencies of NH4+-N and NO2--N decreased from 97.5% and 98.5% to 35.2% and 40.1%, respectively, when the temperature of the reactor dropped from 30℃ to 15℃ at one time. The average removal efficiencies of NH4+-N and NO2--N dropped from 97.7% and 98.6% to 52.7% and 62.4%, respectively, when the ladder cooling method(30℃→25℃→20℃→15℃) was used. The average removal efficiencies of NH4+-N and NO2--N increased initially and then decreased when the pH was increased gradually from 7.7 to 8.5.The highest nitrogen removal efficiency was achieved when the pH was controlled at 8.3 with a substrate ratio of NO2--N/NH4+-N equal to 1.4.

Functional characterization of rice CW-domain containing zinc finger proteins involved in histone recognition.

Histone recognition is important for understanding the mechanisms of histone modification, which play a pivotal role in transcriptional regulation during plant development. Here, we identified three cysteine-tryptophan (CW)-domain containing zinc finger (ZF) proteins involved in histone recognition, namely OsCW-ZF3, OsCW-ZF5 and OsCW-ZF7. Protein sequence analysis showed that they have two unknown motifs in addition to the CW domain. All three OsCW-ZFs were expressed in aerial tissues, with relatively high levels in developing panicles. Subcellular localization revealed that the OsCW-ZFs target the cell nucleus and CW domains are not necessary for their nuclear localization. In contrast to OsCW-ZF3 and OsCW-ZF5 where the CW domains bind histone H3 lysine 4 with different methylated forms (H3K4me), the CW domain from OsCW-ZF7 recognizes only trimethylated histone H3 lysine 4 (H3K4me3). Analysis of mutant suggested that three conserved tryptophan residues in the CW domain are essential for binding to H3K4me. Further study found that OsCW-ZF7 interacts with TAFII20, a transcription initiation factor TFIID 20kDa subunit. Knockout of OsCW-ZF7 caused defective development of awns. This study provides new insights into our understanding of the CW domain and lays a foundation for further investigation of its roles in rice.

OsHSD1, a hydroxysteroid dehydrogenase, is involved in cuticle formation and lipid homeostasis in rice.

Cuticular wax, a hydrophobic layer on the surface of all aerial plant organs, has essential roles in plant growth and survival under various environments. Here we report a wax-deficient rice mutant oshsd1 with reduced epicuticular wax crystals and thicker cuticle membrane. Quantification of the wax components and fatty acids showed elevated levels of very-long-chain fatty acids (VLCFAs) and accumulation of soluble fatty acids in the leaves of the oshsd1 mutant. We determined the causative gene OsHSD1, a member of the short-chain dehydrogenase reductase family, through map-based cloning. It was ubiquitously expressed and responded to cold stress and exogenous treatments with NaCl or brassinosteroid analogs. Transient expression of OsHSD1-tagged green fluorescent protein revealed that OsHSD1 localized to both oil bodies and endoplasmic reticulum (ER). Dehydrogenase activity assays demonstrated that OsHSD1 was an NAD(+)/NADP(+)-dependent sterol dehydrogenase. Furthermore, OsHSD1 mutation resulted in faster protein degradation, but had no effect on the dehydrogenase activity. Together, our data indicated that OsHSD1 plays a specialized role in cuticle formation and lipid homeostasis, probably by mediating sterol signaling. This work provides new insights into oil-body associated proteins involved in wax and lipid metabolism.