[Development on DNA detection kit of fox and its application in common meat products].

OBJECTIVE: To develop a kind of DNA extraction and detection kit for identification of fox source composition. METHODS: Using the modern DNA fingerprint technology, the DNA extraction method was improved, and DNA extraction and detection reagent was developed to obtain the fox polymerase chain reaction( PCR)detection kit. The performance parameters of the kit were evaluated. Finally, 42 samples of fox meat and its mixture with commercial meat products were detected. RESULTS: The kit was proved effective after 20 times of the repeated frozen-thaw and it could be stored at-20 ℃ for 1 year. The specificity test confirmed that fox source composition were detected from 42 samples of fox meat and its mixture with commercial meat. The specificity of the kit was 100%. The minimum detection limit of DNA was 0. 1 ng/µL. CONCLUSION: The fox DNA detection kit could be applied in rapid detection commonmeat of fox source composition, which are good specificity, high sensitivity and good stability.

Increased dominance of terrestrial component in dissolved organic matter in Chinese lakes.

The source composition of chromophoric dissolved organic matter (CDOM) in lakes is closely related to regional environmental changes, human activities, and the carbon cycle. The spectral slope ratio (SR) is an important parameter of CDOM optical components, and combined with remote sensing technology, the source composition of CDOM can be tracked comprehensively and efficiently in large regions. Here, we proposed a CDOM source tracking remote sensing model (CDOM-SR) based on the hue angle (α) to assess the spatial pattern and long-term trend of the CDOM source composition in Chinese lakes (surface area ≥ 1 km2) from 1986 to 2021. Validation results show that the CDOM-SR model has a good SR estimation performance with a median absolute percentage difference, root mean square deviation, median ratio, and median deviation of 17.91 %, 0.23, 1.02, and 0.03, respectively. We found that the average SR of Chinese lakes presents an obvious spatial pattern of high in the west and low in the east due to the difference in human activity intensity and the natural geographical environment. Additionally, we found that the average SR of Chinese lakes from 1986 to 2021 decreased at a rate of - 0.06/10 years, of which 64.37 % of lakes decreased significantly, 15.42 % of lakes had no significant change, and only 20.20 % of lakes increased. The widespread decrease in the average SR indicates that the increasing human activity discharge of terrestrial organic matter has had an important impact on the source composition of the CDOM in Chinese lakes. Our results provide a new resource for remote sensing monitoring of CDOM sources and important insights into lake carbon cycling under the influence of ongoing human activities.

Variations in the concentration, inventory, source, and ecological risk of polycyclic aromatic hydrocarbons in sediments of the Lake Chaohu.

In this study, the ecological risk assessment of PAHs pollution, the existing S-T model was improved and applied to this PAHs pollution assessment in surface sediment in Lake Chaohu. The potential sources and contributions of PAHs in the surface sediment were estimated by molecular diagnostic ratio (MDR) and positive matrix factorization (PMF). The results showed that the average concentration of 16 priority PAHs in the surface sediment was 718.16 ng/g in 2009 and 334.67 ng/g in 2020. In 2020, PAHs concentration has decreased compared to 2009 and the dominant composition has changed from high- to low-molecular-weight PAHs. The estimated PAHs mass inventory of the top 2 cm surface sediment was 2712 tons in 2009 and 1263 tons in 2020. Ecosystem risk assessment by improved S-T models suggested that the overall ecosystem risk of the studied regions was acceptable.

Variations in the concentration, source and flux of polycyclic aromatic hydrocarbons in sediments of the Pearl River Estuary: Implications for anthropogenic impacts.

Variations in the distribution, source composition, mass inventory and burial flux of polycyclic aromatic hydrocarbons (PAHs) in surface sediments from the Pearl River Estuary (PRE) collected in 2011 and 2019 were analyzed to investigate the influence of the anthropogenic activities. Total concentrations of 16 priority PAHs in 2019 (200.40 ± 188.86 ng g-1 dry weight on average) were at the medium level among global bays/estuaries/coastal areas. In 2019, PAH concentrations have decreased by about 50% compared to 2011 and the dominant composition has changed from low- to high-molecular-weight PAHs. The qualitative and quantitative source apportionment analysis indicates that the dominant source of PAHs has shifted from petroleum (40.33%) in 2011 to traffic emission (44.17%) in 2019. The source variation in the PRE can be attributed to the transformation of the energy source structure from petrogenic to pyrogenic in the Pearl River Delta. The estimated PAH mass inventory of the top 5-cm sediment was 38.70 metric tons in 2019, which was about 41 metric tons lower than that in 2011. The average deposition fluxes have dropped from 418.91 ± 261.02 ng cm-2 yr-1 in 2011 to 215.52 ± 246.63 ng cm-2 yr-1 in 2019. The decreasing PAH concentration is related to the sediment coarsening and decline of total organic carbon. These findings in the PRE can be applied to other estuarine environments influenced by anthropogenic activities.

Enhancing microalgae growth and product accumulation with carbon source regulation: New perspective for the coordination between photosynthesis and aerobic respiration.

The coordination between photosynthesis and aerobic respiration under mixotrophic cultivation can make a difference to the growth and biochemical composition of microalgae. However, the response of carbon metabolism to carbon source composition under mixotrophic microalgae cultivation has not been well studied. In this study, the synergistic effects of inorganic carbon (IC) and organic carbon (OC) supply on the growth and carbon metabolism of Chlorella vulgaris under mixotrophic cultivation were investigated. The increase of the proportion of HCO3- had a positive effect on the expression of ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), which promoted the biomass production and carbon fixing. The activity of citrate synthase was attenuated with the increase of IC/OC ratio, indicating that the energy needed for the biomass production in groups with high IC/OC ratio was contributed by photoreaction. Biochemical analysis showed that CO32- was more efficient than HCO3- for carbohydrate and lipid accumulation of Chlorella vulgaris, and the highest amount of carbohydrate (30.2%) and lipid (35.8%) was recorded with the combined use of CO32- and glucose. The results could provide a new perspective on carbon metabolism and enzyme regulation in mixotrophic microalgae cultivation.

[Source Composition Spectrum of Volatile Organic Compounds in Typical Industries in Sichuan].

In this study, typical industries that act as sources of volatile organic compound (VOCs) emission in Sichuan, including automobile manufacturing, wooden furniture, wood-based panel manufacturing, and paint production, were selected and GC-MS national standard analysis to study the organized emission VOC components of every procedure. The spectra of VOCs in the automobile industry were obtained by means of total emission normalization. The results showed that the VOC components of automobile manufacturing, wooden furniture, and oil paint manufacturing enterprises were mainly aromatic hydrocarbons and oxygen-containing compounds, accounting for more than 70% of total VOCs; the emissions from automobile part manufacturing enterprises were mainly aromatic hydrocarbons, with a ratio of over 90%. The proportion of oxygen-containing compounds in the wood-based panel manufacturing industry was found to be up to 97%, mainly caused by the emission of formaldehyde, which accounts for 75%, followed by isopropanol, acetone, and other substances. The proportion of aromatic hydrocarbon and olefin in synthetic resin enterprises is relatively high at over 80%. The olefin species are mainly 1,3-butadiene and 1-butene. Although there are some differences in emission species between different industries, they are mainly composed of aromatic hydrocarbons and oxygenates. Therefore, it is necessary to improve the identification and control of components with high concentration, activity, and toxicity for aromatic hydrocarbons and oxygenates. The source, process, and end process control should be monitored to achieve the effect of total emission reduction.