Decreasing resilience of China's coupled nitrogen-phosphorus cycling network requires urgent action.

The coupled nature of the nitrogen (N) and phosphorus (P) cycling networks is of critical importance for sustainable food systems. Here we use material flow and ecological network analysis methods to map the N-P-coupled cycling network in China and evaluate its resilience. Results show a drop in resilience between 1980 and 2020, with further decreases expected by 2060 across different socio-economic pathways. Under a clean energy scenario with additional N and P demand, the resilience of the N-P-coupled cycling network would suffer considerably, especially in the N layer. China's socio-economic system may also see greater N emissions to the environment, thus disturbing the N cycle and amplifying the conflict between energy and food systems given the scarcity of P. Our findings on scenario-specific synergies and trade-offs can aid the management of N- and P-cycling networks in China by reducing chemical fertilizer use and food waste, for example.

How nitrogen sources influence Mortierella alpina aging: From the lipid droplet proteome to the whole-cell proteome and metabolome.

Arachidonic acid (ARA) is a valuable polyunsaturated fatty acid produced by Mortierella alpina. Although some strategies such as nitrogen supplementation have shown the potential to affect the aging of M. alpina in ways which enable it to produce more ARA, the underlying mechanism remains elusive. Herein, we conducted a systematical analysis of the lipid droplet proteome, as well as the whole-cell proteome and metabolome, in order to elucidate how and why two different nitrogen sources (KNO3 and urea) affect the aging of M. alpina and the corresponding ARA concentration. We found that KNO3 promoted the ARA concentration, while urea accelerated lipid consumption and stimulated the decomposition of mycelia. Although both KNO3 and urea activated carbohydrate metabolic pathways, KNO3 exerted a stronger promoting effect on the pentose phosphate pathway and induced the lipid droplets to participate in the citrate-pyruvate cycle. The activities of malic enzyme and isocitrate dehydrogenase were also promoted more by KNO3. These pathways provided additional substrates and reducing power for ARA synthesis and ROS elimination. Accordingly, since urea showed a weaker promotion of the related pathways, it caused a depression of the antioxidant system and a consequent increase of ROS. These findings facilitate the design of nitrogen supplementation strategies to achieve higher ARA concentrations, and provide guidance for deciphering the mechanisms of similar aging phenomena in other oleaginous microorganisms. SIGNIFICANCE: Polyunsaturated fatty acids such as arachidonic acid (ARA) are valuable nutrients, which play important roles in preventing numerous diseases and facilitating development. Although it has been found for years that ARA production will be increased in the aging process of Mortierella alpina (M. alpina) and nitrogen sources are involved in this process, the underlying mechanism for this phenomenon remains unknown. In this work, we used the subcellular proteomics, whole-cell proteomics and metabolomics methods to explore the mechanisms by which two different nitrogen (KNO3 and urea) affected the aging process of M. alpina. Finally, we gave some new insights for the mechanisms mentioned above. This finding will fuel the technology developments for the ARA production using microbes.

Evaluating the evolution of the Heihe River basin using the ecological network analysis: Efficiency, resilience, and implications for water resource management policy.

One of the most critical challenges in the anthropocentric age is the sustainable management of the planet's increasingly strained water resources. In this avenue, there is a need to advance holistic approaches and objective tools which allow policy makers to better evaluate system-level properties and trade-offs of water resources. This research contributes to the expanding literature in this area by examining the changes to system-level network configurations of the middle reaches of the Heihe River basin from 2000 to 2009. Specifically, through the ecological network analysis (ENA) approach, this research examines changes to the system-level properties of efficiency, redundancy, and evaluates the trade-offs to the resiliency of ecosystem water services of the middle reaches of the Heihe River basin. Our results indicate that while the efficiency of the middle reaches has increased from 2000 to 2009 by 6% and 78% more water is released to the lower reaches, the redundancy of the system has also decreased by 6%. The lower level of redundancy, particularly due to the changes in the groundwater body levels, has critical long-term consequences for the resilience of the water ecosystem services of the middle reaches. In consideration of these holistic trade-offs, two hypothetical alternative scenarios, based on water recycling and saving strategies, are developed to improve the long-term health and resilience of the water system.

The Chemical and Genetic Characteristics of Szechuan Pepper (Zanthoxylum bungeanum and Z. armatum) Cultivars and Their Suitable Habitat.

Szechuan peppers, famous for their unique sensation and flavor, are widely used as a food additive and traditional herbal medicine. Zanthoxylum bungeanum and Z. armatum are both commonly recognized as Szechuan peppers, but they have different tastes and effects. The chemical components, genetic characteristics, and suitable habitat of six cultivars were analyzed in this study. The results indicated that Z. armatum contained a larger proportion of volatile oil, whereas Z. bungeanum produced a more non-volatile ether extraction. The average content of volatile oil and non-volatile ether extract of Z. armatum were 11.84 and 11.63%, respectively, and the average content of volatile oil and non-volatile ether extract of Z. bungeanum were 6.46 and 14.23%, respectively. Combined with an internal transcribed spacer 2 (ITS2) sequence characters and chemical PCA results, six cultivars were classified into their own groups, for the two species in particular. The temperature in January and July were the most significant ecological factors influencing the contents of the Z. armatum volatile oil. However, annual precipitation, temperature in January and relevant humidity had a significant positive correlation with the content of non-volatile ether extract in Z. bungeanum. Thus, the most suitable areas for producing Z. bungeanum cultivars ranged from the Hengduan Mountains to the Ta-pa Mountains, and the regions suitable for Z. armatum cultivars were found to be in the Sichuan Basin and Dalou-Wu mountains. The predicted suitable habitat could be used as a preliminary test area for Szechuan pepper cultivar production.

[Identification of atractylodis macrocephalae rhizoma and atractylodis rhizoma from their adulterants using DNA barcoding].

Atractylodis Macrocephalae Rhizoma and Atractylodis Rhizoma were widely used in strengthening spleen under different disease conditions, and were easily and often misused each other. Therefore, DNA barcode was used to distinguish Atractylodis Macrocephalae Rhizoma and Atractylodis Rhizoma from their adulterants to ensure the safe use. The sequence lengths of ITS2 of Atractylodes macrocephala, Atractylodis Rhizoma (A. lancea, A. japonica and A. coreana) were both 229 bp. Among the ITS2 sequences of A. macrocephala, only one G/C transversion was detected at site 98, and the average GC content was 69.42%. No variable site was detected in the ITS2 sequences of A. lancea. The maximum K2P intraspecific genetic distances of both A. japonica and A. coreana were 0.013. The maximum K2P intraspecific genetic distances of A. macrocephala, A. lancea, A. japonica and A. coreana were less than the minimum interspecific genetic distance of adulterants. The ITS2 sequences in each of these polytypic species were separated into pairs of divergent clusters in the NJ tree. DNA barcoding could be used as a fast and accurate identification method to distinguish Atractylodis Macrocephalae Rhizoma, Atractylodis Rhizoma, from their adulterants to ensure its safe use.