Evaluation of translocation impacts on genetic patterns in farmed and naturalized populations of Mytilus galloprovincialis along the China coast: clues from mitochondrial cytochrome c oxidase I sequences

As an introduced species, Mytilus galloprovincialis has developed into self-sustaining naturalized populations and has been widely cultivated in northern China. The M. galloprovincialis aquaculture industry wholly depends on the movement of naturalized juveniles onto farms. It is, therefore, necessary to understand the genetic effect of continuous spats’ translocation. This study divided 12 localities of M. galloprovincialis along the China coast into three types of populations—farmed, naturalized adjacent farmed, and isolated—to investigate the genetic variation and differentiation. The genetic variability is reflected by haplotype diversity, nucleotide diversity, and the mean number of pairwise differences expressed as farmed populations > naturalized adjacent farmed populations > isolated populations. The Hierarchical analyses and Mantel-test indicated slight divergence between farmed and naturalized populations, northern and southern populations. The farmed and naturalized populations clustered into two separate categories in the neighbor-joining tree except two anthropogenically intervened localities. The present results suggest that the translocation practice positively affected genetic variability and played a vital role in shaping genetic composition. The information obtained in this study provides new insights into the impacts of the translocation culture model of marine mollusks

Decipher the sensitivity of urban canopy air temperature to anthropogenic heat flux with a forcing-feedback framework

The sensitivity of urban canopy air temperature (Ta) to anthropogenic heat flux (QAH) is known to vary with space and time, but the key factors controlling such spatiotemporal variabilities remain elusive. To quantify the contributions of different physical processes to the magnitude and variability of ∆Ta/∆QAH (where ∆ represents a change), we develop a forcing-feedback framework based on the energy budget of air within the urban canopy layer and apply it to diagnosing ∆Ta/∆QAH simulated by the Community Land Model Urban (CLMU) over the contiguous United States (CONUS). In summer, the median ∆Ta/∆QAH is around 0.01 K (W m-2)-1over CONUS. Besides the direct effect of QAH on Ta, there are important feedbacks through changes in the surface temperature, the atmosphere-canopy air heat conductance (ca), and the surface-canopy air heat conductance. The positive and negative feedbacks nearly cancel each other and ∆Ta/∆QAH is mostly controlled by the direct effect in summer. In winter, ∆Ta/∆QAH becomes stronger, with the median value increased by about 20% due to weakened negative feedback associated with ca. The spatial and temporal (both seasonal and diurnal) of ∆Ta/∆QAH and the nonlinear response of ∆Ta to ∆QAH are strongly related to the variability of ca, highlighting the importance of correctly parameterizing convective heat transfer in urban canopy models

Comparative studies on flavor substances of leaves and pericarps of Zanthoxylum bungeanum Maxim. at different harvest periods

Purpose: To study the transformation of the aroma components and pungent constituents of Zanthoxylum bungeanum Maxim. (ZBM) leaves and pericarps at different periods, and to provide a basis for selecting an appropriate harvest time for the pericarps and leaves.Methods: Quantitative analysis of the pungent components of ZBM leaves and pericarps was performed by high performance liquid chromatography (HPLC) while their aroma constituents were analyzed by headspace solid phase micro-extraction combined with gas chromatography-mass spectrometry (HS-SPME-GC-MS).Results: HPLC analysis revealed that hydroxy-α-sanshool was the predominant pungent component in both the leaves and pericarps of different parts of ZBM at different harvest periods, followed by hydroxy- γ-sanshool and hydroxy-β-sanshool. During the growth of ZBM, the contents of pungent substances in the leaves declined gradually, while pungent substances in the pericarps increased. The results of HSSPME- GC-MS analysis showed that linalyl acetate, linalool and limonene were the major aroma components of the leaves and pericarps of ZBM at different harvest periods. During the growth of ZBM, the contents of monoterpenes in the leaves decreased gradually, whereas monoterpenes in the pericarps increased.Conclusion: These results suggest that the pungent and aroma components produced in ZBM at early developmental stages are stored in the leaves, and are gradually transferred to the pericarps at the final developmental stages. Thus, the leaves of ZBM can be used as a new source of food and medicine.Keywords: Zanthoxylum bungeanum Maxim., Pericarp, Pungent components, Aroma component

Inhibitory Effect of Allyl Isothiocyanate on Clostridium perfringens and Its Application of Cooked Pork

The study aimed to investigate the inhibitory activity and mechanism of action of allyl isothiocyanate (AITC) against Clostridium perfringens (C. perfringens). Firstly, the inhibitory effect of AITC on C. perfringens was evaluated by determining the minimum inhibitory concentration (MIC) and plotting the growth curve. Secondly, the effect of AITC on C. perfringens cell membranes was assessed by scanning electron microscopy to observe cell morphology and by measuring cell membrane integrity with a propidium iodide staining assay. In addition, the impact of AITC on the metabolism of C. perfringens was investigated using SDS-PAGE profile and an ATPase activity assay. Finally, the inhibitory effect of AITC on C. perfringens in cooked ground pork was examined. The experimental results showed that AITC could effectively inhibit the growth of C. perfringens, and the MIC of AITC was determined to be 0.1 μL/mL. AITC was able to induce cell membrane deformations, such as rupture and depression, resulting in the loss of C. perfringens cell membrane integrity, and the degree of membrane damage increased with AITC concentration. Meanwhile, AITC could reduce the protein content and ATPase activity of C. perfringens, which had an impact on normal cellular metabolism. Furthermore, the addition of 0.1%~0.4% AITC significantly inhibited the growth of C. perfringens in cooked ground pork (P<0.05). In conclusion, AITC could achieve bacterial inhibition by disrupting the cell membrane of C. perfringens and interfering with protein metabolism, and this study offered a theoretical foundation for the use of natural bacterial inhibitors in the meat industry