A system dynamics urban water management model for Macau, China.

Urban water resources have been facing significant pressure from population growth, urbanization, and climate change. A system dynamics urban water management model was proposed to simulate the dynamic interactions between urban water demands and society, economy, climate, and water conservation. The residents' water conservation willingness was incorporated in the model and water-saving effects were quantified. The simulation results for Macau showed that population size was the main driving force for urban water demand. The change of temperature and precipitation has obvious effects on the landscape water demand. The water demand output is sensitive to the change in population, per capita demand, and temperature. Increased precipitation will reduce urban water demand and increased economic growth will increase water demand. By implementing integrated water conservation measures and improved water conservation willingness, water demand could be reduced by 17.5%.

Integrated water resources management for emergency situations: A case study of Macau.

Integrated urban water management (IUWM) is a useful tool that can be used to alleviate water resource shortages in developing regions like Macau, where 98% of the raw water comes from mainland China. In Macau, scarce water resources deteriorate rapidly in emergency situations, such as accidental chemical spills upstream of the supply reservoir or salty tides. During these times, only the water from the two freshwater reservoirs in Macau can be used. In this study, we developed urban water management optimization models that integrated the raw water supply from the two reservoirs with various proposed governmental policies (wastewater reuse, rainwater collection, and water saving). We then determined how various water resource strategies would influence the urban water supply in Macau in emergency situations. Our results showed that, without imported raw water, the water supply from only the two Macau reservoirs would last for 7.95days. However, when all the government policies were included in the model, the supply could be extended to 13.79days. Out of the three non-conventional water resources, wastewater reuse is the most beneficial for increasing the Macau water supply, and rainwater collection also has great potential.

The Transcriptome of the Zoanthid Protopalythoa variabilis (Cnidaria, Anthozoa) Predicts a Basal Repertoire of Toxin-like and Venom-Auxiliary Polypeptides.

Protopalythoa is a zoanthid that, together with thousands of predominantly marine species, such as hydra, jellyfish, and sea anemones, composes the oldest eumetazoan phylum, i.e., the Cnidaria. Some of these species, such as sea wasps and sea anemones, are highly venomous organisms that can produce deadly toxins for preying, for defense or for territorial disputes. Despite the fact that hundreds of organic and polypeptide toxins have been characterized from sea anemones and jellyfish, practically nothing is known about the toxin repertoire in zoanthids. Here, based on a transcriptome analysis of the zoanthid Protopalythoa variabilis, numerous predicted polypeptides with canonical venom protein features are identified. These polypeptides comprise putative proteins from different toxin families: neurotoxic peptides, hemostatic and hemorrhagic toxins, membrane-active (pore-forming) proteins, protease inhibitors, mixed-function venom enzymes, and venom auxiliary proteins. The synthesis and functional analysis of two of these predicted toxin products, one related to the ShK/Aurelin family and the other to a recently discovered anthozoan toxin, displayed potent in vivo neurotoxicity that impaired swimming in larval zebrafish. Altogether, the complex array of venom-related transcripts that are identified in P. variabilis, some of which are first reported in Cnidaria, provides novel insight into the toxin distribution among species and might contribute to the understanding of composition and evolution of venom polypeptides in toxiferous animals.

Friedmanniella endophytica sp. nov., an endophytic actinobacterium isolated from bark of Kandelia candel.

A coccus-shaped, non-spore-forming actinobacterium, designated strain 4Q3S-3T, was isolated from surface-sterilized bark of the mangrove plant Kandelia candel collected from Cotai Ecological Zones in Macao, China, and tested by a polyphasic approach to clarify its taxonomic position. This actinobacterium was Gram-stain-positive and aerobic. Neither substrate nor aerial mycelia were formed, and no diffusible pigments were observed on the media tested. Strain 4Q3S-3T grew optimally without NaCl at 28-30 °C, pH 7.0-8.0. Phylogenetic analysis based on 16S rRNA gene sequence showed that strain 4Q3S-3T belonged to the genus Friedmanniella and shared the highest 16S rRNA gene sequence similarity with Friedmanniellaflava W6T (96.57 %). The DNA G+C content of strain 4Q3S-3T was 69.5 mol%. The cell-wall peptidoglycan contained ll-2,6-diaminopimelic acid, and MK-9(H4) was the predominant menaquinone. The polar lipids comprised phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, unidentified glycolipid, amino lipids and two unidentified phospholipids. The predominant fatty acids were anteiso-C15 : 0, iso-C16 : 0 and iso-C15 : 0. Based on phylogenetic, phenotypic and chemotaxonomic data, strain 4Q3S-3T represents a novel species of the genus Friedmanniella, for which the name Friedmanniella endophytica sp. nov. is proposed. The type strain is 4Q3S-3T (=DSM 100723T=CGMCC 4.7307T).

Genome-guided Investigation of Antibiotic Substances produced by Allosalinactinospora lopnorensis CA15-2(T) from Lop Nor region, China.

Microbial secondary metabolites are valuable resources for novel drug discovery. In particular, actinomycetes expressed a range of antibiotics against a spectrum of bacteria. In genus level, strain Allosalinactinospora lopnorensis CA15-2(T) is the first new actinomycete isolated from the Lop Nor region, China. Antimicrobial assays revealed that the strain could inhibit the growth of certain types of bacteria, including Acinetobacter baumannii and Staphylococcus aureus, highlighting its clinical significance. Here we report the 5,894,259 base pairs genome of the strain, containing 5,662 predicted genes, and 832 of them cannot be detected by sequence similarity-based methods, suggesting the new species may carry a novel gene pool. Furthermore, our genome-mining investigation reveals that A. lopnorensis CA15-2(T) contains 17 gene clusters coding for known or novel secondary metabolites. Meanwhile, at least six secondary metabolites were disclosed from ethyl acetate (EA) extract of the fermentation broth of the strain by high-resolution UPLC-MS. Compared with reported clusters of other species, many new genes were found in clusters, and the physical chromosomal location and order of genes in the clusters are distinct. This study presents evidence in support of A. lopnorensis CA15-2(T) as a potent natural products source for drug discovery.

Nakamurella endophytica sp. nov., a novel endophytic actinobacterium isolated from the bark of Kandelia candel.

A Gram-stain-positive, aerobic, coccus-shaped, non-spore-forming actinobacterium, designated strain 2Q3S-4-2T, was isolated from the surface-sterilized bark of Kandelia candel, collected from Cotai Ecological Zones in Macao, PR China. It was tested using a polyphasic approach to determine its taxonomic position. Strain 2Q3S-4-2T grew optimally without NaCl at 28-30 °C and at pH 7.0. Substrate mycelia and aerial mycelia were not formed and no diffusible pigments were observed on the media tested. Phylogenetic analysis, based on 16S rRNA gene sequences, suggested that strain 2Q3S-4-2T belonged to the genus Nakamurella, sharing highest 16S rRNA gene sequence similarity with Nakamurella flavida DS-52T (96.76 %). The DNA G+C content of strain 2Q3S-4-2T was 67.8 mol%. The cell-wall peptidoglycan contained meso-diaminopimelic acid and MK-8(H4) was the predominant menaquinone. The predominant polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, unidentified aminophospholipids and phosphatidylinositol. The major fatty acids were iso-C16 : 0, anteiso-C15 : 0, anteiso-C17 : 0 and C16 : 0. On the basis of the phylogenetic, phenotypic and chemotaxonomic analysis, strain 2Q3S-4-2T represents a novel species of the genus Nakamurella, for which the name Nakamurella endophytica sp. nov. is proposed. The type strain is 2Q3S-4-2T ( = DSM 100722T = CGMCC 4.7308T).

Is urban development an urban river killer? A case study of Yongding Diversion Channel in Beijing, China.

The high population and concrete environment alter urban areas by changing temperature, rainfall runoff, and water resource utilization activities. This study was conducted to investigate the water quality features of the Yongding Diversion Channel in Beijing, China, and its relationship with rainfall and urban development. Monthly water quality data were obtained from April to October of 2004 at monitoring sites of Sanjiadian, Gaojing, Luodaozhuang, and Yuyuangtan. The monthly water quality grades from 2007 to 2011 were also investigated and compared with those of other rivers. Dissolved oxygen and pH showed greater decreases after one or two moderate rainfall events than several light rainfall events. The potassium permanganate index (CODMn), ammonia nitrogen (NH3-N) and total phosphorus (TP) increased more after several light rainfall events than after one or two moderate or heavy rainfall events. Pollutant concentrations (CODMn, NH3-N, TP) in downstream regions showed greater changes than those in upstream areas after heavy rainfall events. Intense human activities around the channel greatly influenced the water quality of the channel in rainy season because of runoff pollution; however, heavy rainfall had a strong dilution effect on the pollutant concentrations in rivers. Overall, urban development has obviously deteriorated the water quality of the Yongding Diversion Channel as indicated by an increase in the water quality index from 3.22 in 2008 to 4.55 in 2010. The Pearson correlation between monthly rainfall and water quality indices from 2007 to 2011 ranged from 0.1286 to 0.6968, generally becoming weaker as rainfall and rainfall runoff became more random and extreme.

Occurrence and possible sources of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) along the Chao River, China.

To analyze the possible influence of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) on Miyun Reservoir, 14 soil samples and 1 water sample were collected along the Chao River, which is the main upstream source of the reservoir. A total of 24 kinds of OCPs and 12 kinds of dioxin-like PCBs were measured. Results showed that the ∑OCPs concentration ranged from 0.8145 to 16.8524 ng g(-1), and the ∑PCBs ranged from 0.0039 to 0.0365 ng g(-1). Dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) were the three dominant kinds of OCPs in this region, and the majority component of the PCBs was PCB-118 in both water and soil samples. The OCP ratios suggest that new inputs of lindane exist. DDTs mainly come from old technical inputs. HCHs might come from a new application of lindane, which highlights the importance of prohibited pesticide control. OCP concentrations were higher in corn fields and orchards and lower in forest lands and grasslands, which indicated that OCPs were very much influenced by human activities. The proportion of PCB components in this study area suggested that they mainly came from atmospheric deposition.

Modeling single and repeated dose pharmacokinetics of PFOA in mice.

Perfluorooctanoic acid (PFOA) displays complicated pharmacokinetics in that serum concentrations indicate long half-lives despite which steady state appears to be achieved rapidly. In this study, serum and tissue concentration time-courses were obtained for male and female CD1 mice after single, oral doses of 1 and 10 mg/kg of PFOA. When using one- and two-compartment models, the pharmacokinetics for these two dosages are not consistent with serum time-course data from female CD1 mice administered 60 mg/kg, or with serum concentrations following repeated daily doses of 20 mg/kg PFOA. Some consistency between dose regimens could be achieved using the saturable resorption model of Andersen et al. In this model PFOA is cleared from the serum into a filtrate compartment from which it is either excreted or resorbed into the serum by a process presumed transporter mediated with a Michaelis-Menten form. Maximum likelihood estimation found a transport maximum of T(m) = 860.9 (1298.3) mg/l/h and half-maximum concentration of K(T) = 0.0015 (0.0022) mg/l where the estimated standard errors (in parentheses) indicated large uncertainty. The estimated rate of flow into and out of the filtrate compartment, 0.6830 (1.0131) l/h was too large to be consistent with a biological interpretation. For these model parameters a single dose greater than 40 mg/kg, or a daily dose in excess of 5 mg/kg were necessary to observe nonlinear pharmacokinetics for PFOA in female CD1 mice. These data and modeling analyses more fully characterize PFOA in mice for purposes of estimating internal exposure for use in risk assessment.

Substrate uptake tests and quantitative FISH show differences in kinetic growth of bulking and non-bulking activated sludge.

The competition between filaments and floc formers in activated sludge has been historically described using kinetic selection. However, recent studies have suggested that bacterial storage may also be an important factor in microbial selection, since the dynamic nature of substrate flows into wastewater treatment plants elicit transient responses from microorganisms. Respirometry-based kinetic selection should thus be reevaluated by considering cell storage, and a more reliable method should be developed to include bacterial storage in the analysis of growth of filaments and floc formers in activated sludge. In this study, we applied substrate uptake tests combined with metabolic modeling to determine the growth rates, yields and maintenance coefficients of bulking and non-bulking activated sludge developed in lab scale reactors under feast and famine conditions. The results of quantitative fluorescence in situ hybridization (FISH) showed that the filaments Eikelboom Type 1851, Type 021N, and Thiothrix nivea were dominant in bulking sludge, comprising 42.0 % of mixed liquor volatile suspended solids (MLVSS), with 61.6% of the total filament length extending from flocs into bulk solution. Only low levels of Type 1851 filament length (4.9% of MLVSS) occurred in non-bulking sludge, 83.0% of which grew inside the flocs. The kinetic parameters determined from the substrate uptake tests were consistent with those from respirometry and showed that filamentous bulking sludge had lower growth rates and maintenance coefficients than non-bulking sludge. These results provide support for growth kinetic differences in explaining the competitive strategy of filamentous bacteria.

Relationship of species-specific filament levels to filamentous bulking in activated sludge.

To examine the relationship between activated-sludge bulking and levels of specific filamentous bacteria, we developed a statistics-based quantification method for estimating the biomass levels of specific filaments using 16S rRNA-targeted fluorescent in situ hybridization (FISH) probes. The results of quantitative FISH for the filament Sphaerotilus natans were similar to the results of quantitative membrane hybridization in a sample from a full-scale wastewater treatment plant. Laboratory-scale reactors were operated under different flow conditions to develop bulking and nonbulking sludge and were bioaugmented with S. natans cells to stimulate bulking. Instead of S. natans, the filament Eikelboom type 1851 became dominant in the reactors. Levels of type 1851 filaments extending out of the flocs correlated strongly with the sludge volume index, and extended filament lengths of approximately 6 x 10(8) micro m ml(-1) resulted in bulking in laboratory-scale and full-scale activated-sludge samples. Quantitative FISH showed that high levels of filaments occurred inside the flocs in nonbulking sludge, supporting the "substrate diffusion limitation" hypothesis for bulking. The approach will allow the monitoring of incremental improvements in bulking control methods and the delineation of the operational conditions that lead to bulking due to specific filaments.