The paper discusses the implementation of Hong Kong's tailor-made sewage surveillance programme led by the Government, which has demonstrated how an efficient and well-organized sewage surveillance ...system can complement conventional epidemiological surveillance to facilitate the planning of intervention strategies and actions for combating COVID-19 pandemic in real-time. This included the setting up of a comprehensive sewerage network-based SARS-CoV-2 virus surveillance programme with 154 stationary sites covering 6 million people (or 80 % of the total population), and employing an intensive monitoring programme to take samples from each stationary site every 2 days. From 1 January to 22 May 2022, the daily confirmed case count started with 17 cases per day on 1 January to a maximum of 76,991 cases on 3 March and dropped to 237 cases on 22 May. During this period, a total of 270 “Restriction-Testing Declaration” (RTD) operations at high-risk residential areas were conducted based on the sewage virus testing results, where over 26,500 confirmed cases were detected with a majority being asymptomatic. In addition, Compulsory Testing Notices (CTN) were issued to residents, and the distribution of Rapid Antigen Test kits was adopted as alternatives to RTD operations in areas of moderate risk. These measures formulated a tiered and cost-effective approach to combat the disease in the local setting. Some ongoing and future enhancement efforts to improve efficacy are discussed from the perspective of wastewater-based epidemiology. Forecast models on case counts based on sewage virus testing results were also developed with R2 of 0.9669–0.9775, which estimated that up to 22 May 2022, around 2,000,000 people (~67 % higher than the total number of 1,200,000 reported to the health authority, due to various constraints or limitations) had potentially contracted the disease, which is believed to be reflecting the real situation occurring in a highly urbanized metropolis like Hong Kong.
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•Hong Kong successfully applied Sewage Surveillance for real-time COVID-19 tracking.•The success came from the synergy among government, academic and private sectors.•Sewage data provided early warning with 2–4 days lead time to enhance preparedness.•Robust regression models were developed to estimate actual infection numbers.•City-scale sewage data informed planning of preventive measures to combat COVID-19.
Sewage discharge could be a major source of polycyclic aromatic hydrocarbons （PAHs） in the coastal waters. Stonecutters Island and Shatin Sewage Treatment Works （SCISTW and STSTW） in Hong Kong, ...adopted chemically enhanced primary treatment and biological treatment, respectively. This study aimed at （1） determining the removal efficiencies of PAHs, （2） comparing the capabilities in removing PAHs, and （3） characterizing the profile of each individual PAHs, in the two sewage treatment plants （STPs）. Quantification of 16 PAHs was conducted by a Gas Chromatography. The concentrations of total PAHs decreased gradually along the treatment processes （from 301 ± 255 and 307 ± 217 ns/L to 14.9 ± 12.1 and 63.3 ± 54.1 ng/L in STSTW and SCISTW, respectively）. It was noted that STSTW was more capable in removing total PAHs than SCISTW with average total removal effidency 94.4% ± 4.12% us. 79.2% ± 7.48% （p 〈 0.05）. The removal of PAHs was probably due to sorption in particular matter, confirmed by the higher distribution coefficient of individual and total PAHs in solid samples （dewatered sludge contained 92.5% and 74.7% of total PAHs in SCISTW and STSTW, respectively） than liquid samples （final efffluent-total contained 7.53% and 25.3% of total PAHs in STSTW and SCISTW, respectively）. Despite the impressive capability of STSTW and SCISTW in removing PAHs, there was still a considerable amount of total PAHs （1.85 and 39.3 ks/year, respectively for the two STPs） being discharged into Hone Kon coastal waters, which would be an environmental concern.
This study aimed at investigating the removal efficiencies of perfluorooctanoate (PFOA), perfluorooctane sulfonate (PFOS) and bisphenol A (BPA) of two major sewage treatment works in Hong Kong: ...Stonecutters Island STW (SCISTW) which adopts chemically enhanced primary treatment (CEPT) process and Sha Tin STW (STSTW) which employs biological treatment. Liquid portion (LP) and particulate matter (PM) of liquid sewage samples and sludge samples were collected and followed by liquid chromatograph system. It was found that BPA (44.6 ± 35.1%) generally achieved higher TRE than the two other chemicals (PFOS (−18.8 ± 34.8%) and PFOA (−104 ± 86.8%)) in STSTW (p < 0.05). Most of the PFOA, PFOS and BPA was discharged through final effluent (PFOA: 95.6 ± 1.00% and 94.5 ± 3.13%; PFOS: 77.7 ± 1.48% and 72.6 ± 6.07%; BPA: 99.2 ± 0.950% and 92.8 ± 7.25%, respectively) rather than stored in the sludge/cake (PFOA: 4.45 ± 1.00% and 5.47 ± 3.13%, PFOS: 22.3 ± 1.48% and 27.4 ± 6.07%, BPA: 0.844 ± 0.950% and 7.20 ± 7.25%, respectively). After the sewage purification process, the two STW released considerable amounts of PFOA, PFOS and BPA in the final effluent (PFOA: 0.638 ± 0.227 kg/year; PFOS: 0.409 ± 0.126 kg/year; BPA: 10.4 ± 3.83 kg/year in STSTW; PFOA: 3.08 ± 1.415 kg/year; PFOS: 2.13 ± 0.452 kg/year; BPA: 714 ± 768 kg/year in SCISTW) and in the sludge (PFOA: 0.0360 ± 0.0250 kg/year; PFOS: 0.149 ± 0.00100 kg/year; BPA: 1.09 ± 1.47 kg/year in STSTW; PFOA: 0.139 ± 0.0670 kg/year; PFOS: 0.606 ± 0.0780 kg/year; BPA: 3.05 ± 3.95 kg/year in SCISTW). This study may help to provide crucial information for further development of municipal sewage system in treating synthetic emerging chemicals.
•Wastewater treatment processes (WTP) were not effective in removing PFOA/PFOS.•Majority of PFOA, PFOS and BPA presented in the effluent rather than in the sludge.•Substantial amount of PFOA/S and BPA discharged into the Victoria Harbor, Hong Kong.
This study was to investigate removal efficiencies and profiles of 14 polybrominated diphenyl ether (PBDE) congeners by two different types of sewage treatment work (STW) in Hong Kong: Stonecutters ...Island STW (SCISTW) which uses chemically enhanced primary treatment (CEPT) process and Sha Tin STW (STSTW) which adopts biological treatment. The results indicated that both SCISTW and STSTW had a high total removal efficiency for BDE-47, BDE-99 BDE-209 and total PBDEs (SCISTW: 71.6±15.8, 84.7±12.3, 96.0±2.62 and 87.4±8.02%, respectively; STSTW: 74.8±9.5, 90.7±9.14, 96.2±2.41 and 89.3±2.62%, respectively) and PBDEs were chiefly removed by sorption. However, the profile of PBDEs demonstrated that the relative proportions of BDE-28 and BDE-47 in total PBDEs markedly increased, while that of BDE-209 decreased in the effluent samples of the two sewage treatment works, especially in STSTW. The percentage of BDE-209 in total PBDEs in effluent (49.3%) of SCISTW was 21.2% lower than that in influent (70.5%), and the percentage of BDE-209 in total PBDEs in effluent (13.8%) of STSTW was 34.1% reduced from influent (47.9%). Despite overall removal, the percentage of BDE-47 in total PBDEs in effluent (17.6%) of SCISTW was 6.85% higher than that in influent (10.7%), and the percentage of BDE-47 in total PBDEs in effluent (33.5%) of STSTW was 18.1% increased from influent (16.8%). The increase in proportion of BDE-47 in the effluent might raise environmental and public health concerns. Our study is a first attempt in reporting the PBDE congener profiles in different phases of sewage treatment.
•Wastewater treatment processes (WTP) were very effective in removing PBDEs.•BDE-209 was degraded to BDE-28 and BDE-47 in wastewater treatment processes.•BDE-28 and BDE-47 were the dominant congeners detected in effluent of WTP.
Many enzymes are subject to allosteric control, often with inhibitors and activators binding to the same effector site. Phosphofructokinase in Escherichia coli is such an enzyme, being inhibited by ...phosphoenolpyruvate (PEP) and activated by ADP and GDP. How do individual interactions with effectors affect the balance between activation and inhibition, especially when both ligands share aspects of the same binding site? We find that mutation of a single residue in the effector site, Glu---Ala 187, leads to PEP being an activator rather than an inhibitor. With low concentrations of the substrate fructose-6-phosphate, the mutant enzyme is more than one hundred times more active than wild-type enzyme at millimolar concentrations of PEP. The classical Monod-Wyman-Changeux two-state model is too simple to account for the properties of the mutant enzyme.
A systematic study by site-directed mutagenesis has been conducted on the effector site of phosphofructokinase from Escherichia coli to delineate the role of side chains in binding the allosteric ...activator, GDP, and inhibitor, PEP, and to search for key residues in the allosteric transtion. Target residues were identified from the crystal structure of the enzyme-nucleoside diphosphate complex. It is found that both activator and inhibitor bind to the same set of amino acid side chains. Deletion of positively charged groups (Arg21, Arg25, Arg54, Arg154, and Lys213 mutated to alanine) weakens binding of both effectors by 2-3 kcal/mol, consistent with the disruption of charged hydrogen bonds. Residue Glu187, which is known from the crystal structure to bind the coordinated Mg2+ ion of GDP, is found to have a unique behavior on mutation and appears to be crucial in triggering the allosteric transition. All other residues mutated simply weaken binding of both PEP and GDP in a parallel manner. However, mutation of Glu---Ala187 reverses the roles of GDP and PEP, causing GDP to become an allosteric inhibitor and PEP an activator. Mutation of Glu---Gln187 has only a small effect on the binding of PEP, and both PEP and GDP are inhibitors. Studies are described in which mutations in different subunits of a tetrameric complex complement each other. The effector site is composed of residues from two subunits. In particular, Arg21 and Lys213 in each site are from different subunits. Mutations of either one of these residues abolishes activation by GDP of the homotetramer.
A new vector for the expression of phosphofructokinase (pfk-1) was constructed with pEMBL, which allows reliable, inducible, high-expression, and facile mutagenesis of the gene. Two mutants in the ...effector site of the enzyme were produced by site-specific mutagenesis of residue Tyr-55 to assess the role of its side chain in binding an allosteric inhibitor, phosphoenolpyruvate (PEP), and an activator, guanosine 5'-diphosphate (GDP): Tyr-55---Phe-55 and Try-55---Gly-55. The dissociation constant of PEP from the T state is unaffected by the mutations. Mutation of Tyr-55---Phe-55 only slightly increases the dissociation constant of GDP from the R state, indicating a minimal involvement of the hydroxyl group in binding. A 5.5-fold increase in the dissociation constant of GDP on the mutation of Tyr-55---Gly-55 suggests a small hydrophobic interaction of the aromatic ring of the tyrosine residue with guanine of GDP.
Two-dimensional nuclear magnetic resonance spectroscopy has been used to study the bacterial ribonuclease barnase (MW 12,382). Resonance assignments have been made for protons in all of the 110 ...residues. Analysis of medium- and long-range contacts in NOESY spectra has demonstrated that the major elements of secondary structure in barnase in solution are essentially identical with those found in the crystal structure.
Emerging evidence shows that the efficacy of chemotherapeutic drugs is reliant on their capability to induce immunogenic cell death (ICD), thus transforming dying tumor cells into antitumor vaccines. ...We wanted to uncover potential therapeutic strategies that target ovarian cancer by having a better understanding of the standard-of-care chemotherapy treatment. Here, we showed in ovarian cancer that paclitaxel induced ICD-associated damage-associated molecular patterns (DAMP, such as CALR exposure, ATP secretion, and HMGB1 release)
and elicited significant antitumor responses in tumor vaccination assays
Paclitaxel-induced TLR4 signaling was essential to the release of DAMPs, which led to the activation of NF-κB-mediated CCL2 transcription and IkappaB kinase 2-mediated SNARE-dependent vesicle exocytosis, thus exposing CALR on the cell surface. Paclitaxel induced endoplasmic reticulum stress, which triggered protein kinase R-like ER kinase activation and eukaryotic translation initiation factor 2α phosphorylation independent of TLR4. Paclitaxel chemotherapy induced T-cell infiltration in ovarian tumors of the responsive patients; CALR expression in primary ovarian tumors also correlated with patients' survival and patient response to chemotherapy. These findings suggest that the effectiveness of paclitaxel relied upon the activation of antitumor immunity through ICD via TLR4 and highlighted the importance of CALR expression in cancer cells as an indicator of response to paclitaxel chemotherapy in ovarian cancer.
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