Modeling nitrogen flow in a coastal city-A case study of Xiamen in 2015

Coastal cities, most of them experiencing growing population and rapid urbanization, are facing reactive nitrogen (Nr) pollution crisis and are considered as Nr hotspots worldwide. Increased human activities generate drastic effects on the nitrogen (N) flows of coastal cities. Nevertheless, the N flows of coastal cities are not clearly understood, and the existing city-scale N flow models cannot depict the detailed N flows in coastal cities. Here, we developed a NItrogen MOdel for COastal ciTy (NIMOCOT) which includes four processes and 14 subsystems and used the Material Flow Analysis (MFA) method to model detailed N flows by taking Xiamen as a case study. The results showed that total N inputs to and outputs from Xiamen in 2015 were 403.8 and 201.7 Gg respectively, with half of total N inputs accumulated in the city. The top two N inputs were N embodied in nonfood goods consumption by households and fossil fuel combustion, accounting for 48.5% and 38.5% of total N inputs to Xiamen respectively. After city internal consumption, 109.5 Gg NOx were emitted mainly from energy and industrial subsystems, accounting for 93.2% of total gaseous Nr emissions to the atmosphere. In the typical coastal city, shipping contributed to 34.0% of the total gaseous Nr emissions to the atmosphere in the transportation sector, ranked after highway (58.0%). Moreover, the largest Nr contributor to the hydrosphere came from riparian import (56.0%) which has a significant impact on the hydrosphere of Xiamen. Our results indicated that enhancing the remove ratio of NOx emissions during fossil fuel consumption, and strengthening watershed managements to low riparian N imports from upstream will be useful for reducing N contaminants in environment of Xiamen, and NIMOCOT model is suitable for tracking the key N pollutant sources and could help to make decisions on cutting associate pollutants in coastal cities.

Transboundary Environmental Footprints of the Urban Food Supply Chain and Mitigation Strategies

Food supply has been the central issue of human development for millennia and has become increasingly critical in an urbanizing world. However, the environmental footprints and associated mitigation strategies of food consumption have rarely been comprehensively characterized at urban or regional scales. Here, we analyze the water, carbon, reactive nitrogen, and phosphorus footprints of food consumption in Chinese urban regions and demonstrate how such information can help to formulate tailored mitigation strategies. The results show that in three of the largest urban regions of China, 44-93% of the four footprints are embodied in transboundary food supply. The size of the footprints and the effectiveness of mitigation measures in food supply chain vary across the environmental footprints and urban regions. However, targeting agriculture and food processing sectors in Hebei, Shandong, and Henan provinces can reduce these footprints by up to 47%. Our findings show that the analysis of the environmental footprints along the transboundary food supply chains could inform individualized and effective mitigation targets and strategies.

Prevalence and characteristics of Salmonella isolates recovered from retail raw chickens in Shaanxi Province, China

In this study, we evaluated the prevalence of Salmonella in retail raw chickens in Shaanxi Province, China, on a monthly basis. In addition, we studied the antibiotic susceptibility, serotype, and genotype of Salmonella isolates and explored their relationships with sampling time, location, market type, and chicken type. The results showed that Salmonella was more prevalent in chickens sampled during the spring and summer than during the autumn and winter. Thirty-nine serotypes were identified from 406 Salmonella isolates, of which Salmonella typhimurium (16.7%) was the most prevalent. Other prevalent serotypes included S. thompson (12.8%), S. essen (9.1%), S. infantis (6.9%), S. rissen (5.7%), and S. enteritidis (5.4%). Approximately 71.4% of the 406 isolates were resistant to 3 or more antibiotics, 11.8% to 12 or more, and 1.7% to all 14 antibiotics tested. The most frequently detected resistance was to trimethoprim/sulfamethoxazole (82.0%), followed by nalidixic acid (71.9%) and tetracycline (59.4%). The frequencies of resistance to ampicillin, chloramphenicol, and amoxicillin/clavulanic acid were moderately high (∼50% each). Resistance to kanamycin, ceftiofur, streptomycin, gentamicin, and ciprofloxacin was less common (<40% each). Serotype distribution and antibiotic susceptibility of Salmonella isolates were related to sampling time, location, chicken type, and market type. Isolates recovered from the same sampling time, market type, location, and chicken type commonly exhibited identical or similar genotypes and antibiotic resistance profiles. However, DNA profiles and antibiotic resistance phenotypes of isolates within some serotypes were diverse. Our results revealed that multiple Salmonella subtypes with antibiotic resistance were prevalent in retail raw chickens in Shaanxi Province. Our study findings provide information for developing preventive measures against contamination of retail foods with Salmonella.

Detection of plasmid-mediated tigecycline-resistant gene tet(X4) in Escherichia coli from pork, Sichuan and Shandong Provinces, China, February 2019

The plasmid-mediated high-level tigecycline resistance gene, tet(X4), was detected in seven Escherichia coli isolates from pork in two Chinese provinces. Two isolates belonged to the epidemic spreading sequence type ST101. Tet(X4) was adjacent to ISVsa3 and concurrent with floR in all seven isolates. In addition to IncFIB, the replicon IncFII was found to be linked to tet(X4). This report follows a recent detection of tet(X3)/(X4) in E. coli from animals and humans in China.

Diet shift: Considering environment, health and food culture

Most studies have suggested that dietary choices have effects on both the environment and human health; however, they have ignored food culture, which is both an "independent variable" and a "dependent variable" of diet choice. The purpose of this study is to explore a diet optimization path that meets nutritional needs and has little impact on the environment, while respecting the local food culture to a large extent. We took China's Xinjiang Uygur autonomous region (hereinafter referred to as "Xinjiang") as the case area because Xinjiang is a multiethnic region with a unique food culture characterized by a high proportion of mutton in meat. According to the study's calculation, the current diet in Xinjiang has a high carbon footprint (CF), water footprint (WF) and ecological footprint (EF) and does not present the nutritional structure of a balanced diet. Considering the trade-offs among environmental carrying capacity, health and food culture is the challenge of changing the local food structure. With the method of multi-objective optimization, we propose "optimal diets", which show potential for mitigating environmental impacts and improving the state of health. Most importantly, one of the optimized diets is most desirable because it considers the preservation of the existing food culture. This study demonstrates the feasibility of providing a route for diet transformation that has double benefits regarding the environment and health, or even triple benefits regarding the environment, health and cultural acceptability.

THU0243 HSA_CIRC_0123190 FUNCTIONS AS A COMPETITIVE ENDOGENOUS RNA TO REGULATE APLNR EXPRESSION BY SPONGING HSA-MIR-483-3P IN LUPUS NEPHRITIS

Background:

Lupus nephritis (LN) is one of the most severe complications of systemic lupus erythematosus (SLE). Circular RNAs(circRNAs) can act as competitive endogenous RNAs (ceRNAs) to regulate gene transcription, which is involved in mechanism of many diseases, such as, autoimmunity diseases. However, the role of circRNA in lupus nephritis has been rarely reported.

Objectives:

In this study, we aim to investigate the clinical value of circRNAs and explore the mechanism of circRNA involvement in the pathogenesis of LN.

Methods:

Renal tissues from three untreated LN patients and three normal controls (NCs) were used to identify differently expressed circRNAs by RNA sequencing (RNA-seq). Validated assays were used by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Correlation analysis and receiver operating characteristic (ROC) curve were used to reveal the clinical value of selected circRNA, miRNA and mRNA. The interactions between circRNA and miRNA, or miRNA and mRNA were further determined by luciferase reporter assay. The degrees of renal fibrosis between the two groups were compared by Masson-trichome staining and immunohistochemistry staining.

Results:

159 circRNAs were significantly dysregulated in LN patients compared with NC group. The expression of hsa_circ_0123190 was significantly decreased in renal tissues of patients with LN (p=0.014), as same as the sequencing results. The area under the ROC curve of hsa_circ_0123190 in renal tissues was 0.820. Bio-informatic analysis and luciferase reporter assay illustrated that hsa_circ_0123190 can act as a sponge for hsa-miR-483-3p which was also validated to interact with APLNR mRNA. APLNR mRNA expression was positively related with chronicity index (CI) of LN (R2=0.452,p=0.033). Finally, the factors of renal fibrosis, especially TGF-β (p=0.018), were more pronounced in the LN group.

Conclusion:

Hsa_circ_0123190 could function as a ceRNA to regulate APLNR expression involved in renal fibrosis by sponging hsa-miR-483-3p in LN

References:

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Disclosure of Interests:

None declared

Spatio-temporal dynamics of nitrogen use efficiencies in the Chinese food system, 1990-2017

Understanding the influence factors of nitrogen (N) use efficiencies (NUEs) in different stages of the food system at the provincial scale is critical to achieving cleaner food production while ensuring food security. Nevertheless, they are not well understood. Here we comprehensively analyzed NUE and its influence factors at different stages of the provincial food system. The results showed that per unit agricultural land N input increased by 5-92% in 27 provinces, during 1990-2010, resulting in a low NUE for the crop system when N input per unit agricultural land exceeded about 400 kg N ha^-1. This situation has brought some positive changes, as N input decreased by 3-271 kg N ha^-1 in 77% of the provinces in 2017, relative to that of 2010, but 10 provinces were still over 450 kg N ha^-1 in 2017. Animal food production is expected to continue to expand because 35% and 68% of provinces' urban and rural households, respectively, were still below the recommended minimum animal food N consumption recommendation in 2017, posing great challenges for reducing environmental N pollution. An exciting result is that the NUE of the animal system can be improved by increasing the share of animal food contributed by poultry, eggs, milk and fish, to align with the diets recommended by the Chinese Nutrition Society. NUEs of the provincial food systems excluding Inner Mongolia, Xinjiang, Qinghai and Tibet, would increase by 13% if the net imported food N increased by 1 kg capita^-1. Nevertheless, virtual NUE-including N input for imported food in the calculation of NUE-should be considered for accurate comparison of the NUEs of the provincial food systems, especially in highly urbanized areas, while N input for non-food animals should be excluded for accurate evaluation of the NUE in pastoral areas, considering their special production systems and feeding structures.

Genes and Proteomes Associated With Increased Mutation Frequency and Multidrug Resistance of Naturally Occurring Mismatch Repair-Deficient Salmonella Hypermutators

The emergence of antibiotic-resistant Salmonella through mutations led to mismatch repair (MMR) deficiency that represents a potential hazard to public health. Here, four representative MMR-deficient Salmonella hypermutator strains and Salmonella Typhimurium LT2 were used to comprehensively reveal the influence of MMR deficiency on antibiotic resistance among Salmonella. Our results indicated that the mutation frequency ranged from 3.39 × 10^–4 to 5.46 × 10^–2 in the hypermutator. Mutation sites in MutS, MutL, MutT, and UvrD of the four hypermutators were all located in the essential and core functional regions. Mutation frequency of the hypermutator was most highly correlated with the extent of mutation in MutS. Mutations in MMR genes (mutS, mutT, mutL, and uvrD) were correlated with increased mutation in antibiotic resistance genes, and the extent of antibiotic resistance was significantly correlated with the number of mutation sites in MutL and in ParC. The number of mutation sites in MMR genes and antibiotic resistance genes exhibited a significant positive correlation with the number of antibiotics resisted and with expression levels of mutS, mutT, and mutL. Compared to Salmonella Typhimurium LT2, a total of 137 differentially expressed and 110 specifically expressed proteins were identified in the four hypermutators. Functional enrichment analysis indicated that the proteins significantly overexpressed in the hypermutators primarily associated with translation and stress response. Interaction network analysis revealed that the ribosome pathway might be a critical factor for high mutation frequency and multidrug resistance in MMR-deficient Salmonella hypermutators. These results help elucidate the mutational dynamics that lead to hypermutation, antibiotic resistance, and activation of stress response pathways in Salmonella.

Identification and Quantification of Nonviable Lactobacillus pentosus Cells in a Health Food Product

BACKGROUND

The lack of formal protocol to verify the nonviable cell probiotic product authenticity blocks its registration and supervision process.

OBJECTIVE

To develop a protocol for identification, enumeration, and purity determination of a Lactobacillus pentosus nonviable cell product.

METHODS

The 16S ribosomal RNA (rRNA) sequencing, 16S rRNA metagenomic analysis, whole-genome sequencing, matrix-assisted laser desorption ionization-time of flight MS (MALDI-TOF-MS), and FACSMicroCount™ system were applied to establish a protocol of identification, enumeration and purity determination of a Lactobacillus pentosus nonviable cell product.

RESULTS

The 1530 bp of 16S rRNA sequence could only identify the bacteria at genus level, but the MALDI-TOF-MS could identify both the nonviable cell and fresh culture to species level with high confidence. Metagenomic analysis of the 16S rRNA amplicon could recognize Lactobacillus as the dominant genus in the nonviable cell product. The total number of matching k-mers between the nonviable cell product and the L. pentosus BGM48 in the GenBank was the highest. The 95% confidence interval of the nonviable cell concentration in the product was determined as 4.31-4.68 × 1010 cells/g through the BD FACSMicroCount system.

CONCLUSIONS

This validation protocol offers an executable approach that can verify microbial contents in nonviable cell products and ensure the compliance with label claims.

HIGHLIGHTS

The established validation protocol could determine the nonviable cell species through MALDI-TOF-MS, the concentration through FACSMicroCount system, and the purity and strain level identification through metagenomic analysis of 16S rRNA and the genomic deoxyribonucleic acid.

Effects of early nutritional intervention on oral mucositis in patients with radiotherapy for head and neck cancer

BACKGROUND

To observe the effect of early nutritional intervention on radiation-induced oral mucositis and nutritional status in patients with head and neck cancer (HNC).

METHODS

A total of 54 HNC patients were divided into early (28 cases) and late (26 cases) nutritional intervention groups. The early group received enteral nutrition at the beginning of radiotherapy (RT), while the late group received enteral nutrition after restricted feeding. Operators reported and assessed the timing and extent of oral mucositis and nutritional status during treatment. The nutritional status assessment indicators included body weight; body mass index (BMI); Patient-Generated-Subjective Global Assessment (PG-SGA) score; levels of albumin, hemoglobin and pre-albumin and total lymphocyte count.

RESULTS

The incidence of high-grade oral mucositis was significantly lower in the early group than that in the late group (P < 0.05). Nutritional status assessments showed more significant weight and BMI losses in the late group than in the early group at weeks 4 and 7 after RT (P < 0.01). The albumin decreased in the late group at week 7 after RT was more significant than that in the early group (P < 0.05). Albumin, hemoglobin and pre-albumin levels and total lymphocyte count decreased significantly in both groups (P > 0.05). During therapy, more patients in the early group were well-nourished and fewer were malnourished according to PG-SGA scores (P < 0.05).

CONCLUSION

Early nutritional intervention can reduce the incidence of high-grade oral mucositis during RT in patients with HNC and improve the nutritional status during treatment, which has important clinical significance.

Identifying the trade-offs between climate change mitigation and adaptation in urban land use planning: An empirical study in a coastal city

Cities play a significant role in climate change mitigation and adaptation. Urban land planning shapes the urban form and is considered to be an effective approach for climate change mitigation and adaptation. Yet, there is little knowledge about what urban forms can reduce both greenhouse gas (GHG) emissions and climate stresses while considering trade-offs between them. Here, we investigate the role of urban land use in both climate change mitigation and adaptation. In particular, we assess quantitatively the competition between strategies for mitigation and adaptation and identify potential win-win solutions in land use responses. Using a coastal city as a case study, we find that the land use strategies for unilateral mitigation or adaptation can cause contradicting consequences with respect to the reductions in GHG emissions and climate stresses, i.e. reductions in GHGs could increase climate stresses or vice versa. Poorly integrated strategies potentially may compromise international efforts to meet the Climate Action in the Sustainable Development Goals. Properly integrated mitigation and adaptation strategies, or climate-sensitive land use planning, however, can lead to win-win outcomes and eventually achieve co-benefits. Yet, any co-benefits will gradually diminish if there is a delay in climate-sensitive land use planning, implying growing GHGs and intensified climate stresses. Our analysis indicates that integrating climate change mitigation and adaptation in urban land use needs to be enacted as soon as possible: any delays in implementation reduce the window to act to maximize the co-benefits.

Determination of Total Dietary Fiber (CODEX Definition) by Enzymatic-Gravimetric Method and Liquid Chromatography: Collaborative Study

A method for the determination of total dietary fiber (TDF), as defined by the CODEX Alimentarius, was validated in foods. Based upon the principles of AOAC Official MethodsSM 985.29, 991.43, 2001.03, and 2002.02, the method quantitates high- and low-molecular-weight dietary fiber (HMWDF and LMWDF, respectively). In 2007, McCleary described a method of extended enzymatic digestion at 37C to simulate human intestinal digestion followed by gravimetric isolation and quantitation of HMWDF and the use of LC to quantitate low-molecular-weight soluble dietary fiber (LMWSDF). The method thus quantitates the complete range of dietary fiber components from resistant starch (by utilizing the digestion conditions of AOAC Method 2002.02) to digestion resistant oligosaccharides (by incorporating the deionization and LC procedures of AOAC Method 2001.03). The method was evaluated through an AOAC collaborative study. Eighteen laboratories participated with 16 laboratories returning valid assay data for 16 test portions (eight blind duplicates) consisting of samples with a range of traditional dietary fiber, resistant starch, and nondigestible oligosaccharides. The dietary fiber content of the eight test pairs ranged from 11.57 to 47.83. Digestion of samples under the conditions of AOAC Method 2002.02 followed by the isolation and gravimetric procedures of AOAC Methods 985.29 and 991.43 results in quantitation of HMWDF. The filtrate from the quantitation of HMWDF is concentrated, deionized, concentrated again, and analyzed by LC to determine the LMWSDF, i.e., all nondigestible oligosaccharides of degree of polymerization 3. TDF is calculated as the sum of HMWDF and LMWSDF. Repeatability standard deviations (sr) ranged from 0.41 to 1.43, and reproducibility standard deviations (sR) ranged from 1.18 to 5.44. These results are comparable to other official dietary fiber methods, and the method is recommended for adoption as Official First Action.

Development of a Method for the Detection of -Lactamases in Milk Samples

With the rapid growth of the dairy industry and the establishment of strict antimicrobial residue limits in the People's Republic of China's (PRC) milk supply, a -lactamase product known as antimicrobial destroyer was introduced into dairy production without regulatory review. We developed a method for detecting this product in milk samples based on a modified cylinder plate method. The presence of -lactamase is defined as a difference between the inhibitory zones of the test samples (supplemented with 25 g/mL sulbactam plus 0.5 g/mL penicillin G) and control samples (supplemented only with 0.5 g/mL penicillin G) 3 mm. Using this method, 77 individually packaged milk samples were randomly collected from 5 retail stores in 3 cities over a 4-month period (May to August 2006). Of the 77 samples, 49 were found to be -lactamase-positive. In 2 undiluted milk samples showing extremely high -lactamase activity, 25 g/mL sulbactam could not inhibit penicillin G activity. Because there is a lack of safety data on -lactamases in milk products, these data indicated a potentially serious safety concern for the dairy industry in the PRC.

Assessing Agricultural Livelihood Vulnerability to Climate Change in Coastal Bangladesh

The adverse impacts of climate change exert mounting pressure on agriculture-dependent livelihoods of many developing and developed nations. However, integrated and spatially specific vulnerability assessments in less-developed countries like Bangladesh are rare, and insufficient to support the decision-making needed for climate-change resilience. Here, we develop an agricultural livelihood vulnerability index (ALVI) and an integrated approach, allowing for (i) mapping out the hot spots of vulnerability distribution; (ii) identifying key factors of spatially heterogeneous vulnerability; and (iii) supporting intervention planning for adaptation. This study conceptualized vulnerability as a function of exposure, sensitivity, and adaptive capacity by developing a composite index from a reliable dataset of 64 indicators comprising biophysical, agro-ecological, and socioeconomic variables. The empirical studies of coastal Bangladesh revealed that Bhola, Patuakhali, and Lakshmipur districts, around the mouth of the deltaic Meghna estuaries, are the hot spot of vulnerability distribution. Furthermore, the spatially heterogeneous vulnerability was triggered by spatial variation of erosion, cyclones, drought, rain-fed agriculture, land degradation, soil phosphorus, crop productivity, sanitation and housing condition, infant mortality, emergency shelters, adoption of agro-technology. The integrated approach could be useful for monitoring and evaluating the effectiveness of adaptation intervention by substituting various hypothetical scenarios into the ALVI framework for baseline comparison.

Transforming nitrogen management of the urban food system in a food-sink city

Nitrogen flows in urban food systems are attracting increasing concern. However, characteristics of nitrogen flow and systematic measures to reduce reactive nitrogen losses in the food systems of consumption-oriented cities in developing countries have not been well understood, especially in a quantitative way. This study empirically investigates the transforming nitrogen flows of an urban food system in a food-sink city in China, with a nitrogen metabolism model. Three types of nitrogen loads transfer are identified: from production to consumption side, between different environmental media, and from areas within to areas beyond the city boundary. By integrating sensitivity analysis into the metabolism model, increases in the sewage treatment rate, the sewage nitrogen removal rate, and the ratio of animal excreta returned to field are found to contribute the most to the water nitrogen load reduction, and reducing food waste at the consumer level is the most influential measure for lowering soil nitrogen loads, under the existing nitrogen flow regime. Additionally, a three-tier template framework is proposed to streamline city strategies (prevention, abatement, recycling, regional cooperation, etc.) for reducing the N loads of urban food systems, providing references for sustainable nutrient management in urban ecosystems.

[The expression of VHL/HIF signaling pathway in the erythroid progenitor cells with chronic mountain sickness]

Objective: To investigate the expression and interaction of VHL/HIF-α pathways including HIF-1α, HIF-2α as well as VHL in erythroid progenitor cells of bone marrow from chronic mountain sickness (CMS) patients. Methods: A total of 25 patients with CMS and 21 healthy controls were recruited for this study. The CD71(+)CD235a(+) cells in bone marrow mononuclear cells, marked as erythroid progenitor cells, were isolated using MACS separation technology. The expression levels of HIF-1α, HIF-2α and VHL in erythroid progenitor cells were detected by Western blotting and real-time fluorescence quantitative PCR. Results: The mRNA levels of HIF-2α were higher in erythroid progenitor cells of CMS than in healthy controls [1.68 (0.81, 2.22) vs 0.98 (0.60, 1.19), P<0.05], while HIF-1α and VHL mRNA levels were similar between the two groups (P>0.05). Spearman analyses indicated that HIF-2α mRNA was positively associated with hemoglobin (Hb) levels in the erythroid progenitor cells of CMS (ρ=0.504, P<0.05). Furthermore, the mRNA level of HIF-2α was correlated with the mRNA level of VHL in the erythroid progenitor cells of CMS (ρ=0.647, P<0.05).The protein levels of HIF-2α in the erythroid progenitor cells of CMS were higher than that of healthy controls [0.94(0.68, 3.30) vs 0.59(0.30, 0.88), P<0.05], but the protein levels of HIF-1α and VHL were similar between the two groups (P>0.05). Conclusions: The abnormal increased expression of HIF-2α in the erythroid progenitor cells of CMS patients leads to the abnormal expression of hypoxia sensitive genes downstream, participating in the occurrence and development of CMS.

Characterization of an Oxacillin-Susceptible mecA-Positive Staphylococcus aureus Isolate from an Imported Meat Product

Methicillin-resistant Staphylococcus aureus (MRSA) isolates that carry mecA but are oxacillin susceptible (OS-MRSA; oxacillin minimum inhibitory concentration [MIC] ≤2 μg/mL) are increasingly reported worldwide in the past decade. In this study, an OS-MRSA isolate FC1102921 from an imported meat sample was characterized and the oxacillin resistance mutation frequency and mutant prevention concentration (MPC) to oxacillin was determined. Isolate FC1102921 was pvl negative and contained SCCmec V (5C2&5), the sequence type and spa type were identified as ST398-t034. The MPCs of isolate FC1102921 to oxacillin was 16 μg/mL. The resistance mutation frequency of isolate FC1102921 to oxacillin was 0.036%. The expression of mecA in isolate FC1102921 was detectable, but the mecA expression in the mutant isolate FC1102921m increased 13.8-folds. Our data indicated that S. aureus FC1102921 was not a hypermutator, and the high-resistance mutation frequency of S. aureus FC1102921 was specific to oxacillin and penicillin. SCCmec V region of isolate FC1102921 and FC1102921m was identical, functional blaI and blaR1 were identified in SCCmec region of both isolates, and no plasmid loss was identified in mutant isolate FC1102921m. To the best of our knowledge, this is the first report of the resistance mutation frequency and MPC study of an OS-MRSA ST398-t034 isolate. The high oxacillin MPC value and high oxacillin resistance mutation frequency was not related to a curable plasmid as previously reported, which further highlighted that an in-depth study should be carried out to clarify the mechanism and role of the OS-MRSA isolates in the emergence and transmission of MRSA ST398-t034.

Driving forces of nitrogen flows and nitrogen use efficiency of food systems in seven Chinese cities, 1990 to 2015

The effects of population growth (PG), dietary changes (DC), native rural-to-urban migration (NM), migration from regions distant from the cities (M), and agricultural patterns and practices (AP) on N use in food systems and the food trade, and on apparent and virtual nitrogen (N) and N use efficiencies (NUE), at the city scale, are not well understood. Here we selected seven Chinese cities as the study subjects, analyzed the food trade effects on apparent and virtual N inputs and NUE, and quantified the relative magnitudes of these factors on N inputs to cities' food systems during 1990-2015, by designing several scenarios. Our results show that food-sink cities are relying more and more on external food and feed, but in 2015 they transferred 33.8-74.9% of their N input for food or feed productions to areas outside their boundaries, and the food trade showed different effects on the virtual N cost of food N consumption. Apparent NUEs of food systems were 33.1-74.9% higher than those calculated from virtual N costs in Beijing, Tianjin, Shanghai, Lanzhou and Xiamen in 2015. But in cities that export large amounts of food and feed-for example, Chongqing and Changchun-apparent NUE was underestimated by 4.0-46.4% relative to virtual NUE. Native PG, DC, NM, M, and AP accounted for 1.2-14.1%, -6.6-30.0%, 0.6-8.2%, -7.7-131.0%, and -43.8-12.8%, respectively, of the increase in virtual N inputs associated with cities' food systems in 2015, compared to 1990. Our study concludes that M, DC, and AP changes should be considered for mitigating N input in these Chinese cities, and virtual N exports induced by the food trade should also be included if the city is a net food exporter. Selective food trade could help improve the NUE of cities' food systems, and virtual NUE should be used as an indicator, rather than apparent NUE.

Comprehensive Environmental Assessment of Potato as Staple Food Policy in China

The Chinese government projected 30% of total consumed potatoes as a staple food (PSF) by 2020. We comprehensively assessed the potential impacts of PSF on rice and flour consumption, rice and wheat planting, energy and nutrient supply, irrigation-water, chemical nitrogen (N), phosphorus pentoxide (P₂O₅) and potassium oxide (K₂O) fertilizer inputs and total greenhouse gases (GHG) emission for potatoes, rice and wheat, by assuming different proportions of potato substitutes for rice and flour. The results showed that per capita, 2.9 ± 0.3 and 4.7 ± 0.5 kg more potatoes per year would enter the Chinese staple-food diet, under the government’s target. PSF consumed are expected to reach 5.2 ± 0.7 Tg yr⁻¹, equivalent to substituting potatoes for 4.2 ± 0.8–8.5 ± 0.8 Tg yr⁻¹ wheat and 5.1 ± 0.9–10.1 ± 1.8 Tg yr⁻¹ rice under different scenarios. While this substitution can increase the nutrient supply index by 63% towards nutrient reference values, it may induce no significant effect on staple-food energy supply with lower chemical fertilizer (except for K₂O) and irrigation-water inputs and GHG emissions in different substitution scenarios than the business as usual scenario. The reduction in rice and wheat demands lead to wheat in the North China Plain and early rice decrease by 6.1–11.4% and 12.1–24.1%, respectively. The total GHG reduction is equal to 1.1–9.0% of CO₂ equivalent associated with CH₄ and N₂O emitted from the Chinese agroecosystem in 2005. The saved irrigation water for three crops compared to 2012 reaches the total water use of 17.9 ± 4.9–21.8 ± 5.9 million people in 2015. More N fertilizer, irrigation-water, and GHG can be reduced, if the PSF ratio is increased to 50% together with potato yield improves to the optimal level. Our results implied that the PSF policy is worth doing not only because of the healthier diets, but also to mitigate resource inputs and GHG emissions and it also supports agricultural structure adjustments in the areas of irrigated wheat on the North China Plain and early rice across China, designed to increase the adaptability to climate change.

An optimized TaqMan real-time PCR method for authentication of ASINI CORII COLLA (donkey-hide gelatin)

In this study, probe/primers of high specificity and sensitivity were selected to analyze donkey-hide gelatin for donkey DNA and to look for horse, ox, and pig DNA as possible adulterants. The mitochondrial CO I genes in donkey, horse, and ox were selected as target sequences for design and synthesis of three pairs of specific probes and primers. In addition, eight pairs of probe/primers were obtained via literature search. Out of these eleven groups of probe/primers, those with the highest specificity and sensitivity were selected, which was fulfilled by the screening firstly with animal hide samples then the hide-glue samples. Other parameters that might affect detection specificity and efficiency-such as the amount of sampling and final concentration of primers-were also optimized. Replication tests were also conducted. The results showed that the selected probe/primers could accurately detect donkey DNA and horse, ox, and pig DNA in gelatin samples with good reproducibility. Analysis of four samples of on-market gelatin using this assay showed that two of the four samples indeed contained only donkey DNA, whereas the other two samples contained both donkey and horse DNA, indicating adulteration of these samples with horse hide. These results indicate that the TaqMan probe real-time PCR method can be used for identifying the purity of donkey DNA in gelatin samples, and can provide technical support for identifying adulterations in the gelatin market.