Engineered cytochrome fused extracellular matrix enabled efficient extracellular electron transfer and improved performance of microbial fuel cell.

Microbial fuel cell (MFC) was a promising technology for energy harvesting from wastewater. However, inefficient bacterial extracellular electron transfer (EET) limited the performance as well as the applications of MFC. Here, a new strategy to reinforce the EET by engineering synthetic extracellular matrix (ECM) with cytochrome fused curli was developed. By genetically fusing a minimal cytochrome domain (MCD) with the curli protein CsgA and heterogeneously expressing in model exoelectrogen of Shewanella oneidensis MR-1, the cytochrome fused electroactive curli network was successfully constructed and assembled. Interestingly, the strain with the MCD fused synthetic ECM delivered about 2.4 times and 2.0 times higher voltage and power density output than these of wild type MR-1 in MFC. More impressively, electrochemical analysis suggested that this synthetic ECM not only introduced cytochrome of MCD, but also attracted more self-secreted electrochemically active substances, which might facilitate the EET and improve the MFC performance. This work demonstrated the possibility to manipulation the EET with ECM engineering, which opened up new path for exoelectrogen design and engineering.

Cytochrome C catalyzed oxygen tolerant atom-transfer radical polymerization.

Atom-transfer radical polymerization (ATRP) is a well-known technique for controlled polymer synthesis. However, the ATRP usually employed toxic heavy metal ionas as the catalyst and was susceptible to molecular oxygen, which made it should be conducted under strictly anoxic condition. Conducting ATRP under ambient and biocompatible conditions is the major challenge. In this study, cytochrome C was explored as an efficient biocatalyst for ATRP under biocompatible conditions. The cytochrome C catalyzed ATRP showed a relatively low polymer dispersity index of 1.19. More interestingly, the cytochrome C catalyzed ATRP showed superior oxygen resistance as it could be performed under aerobic conditions with high dissolved oxygen level. Further analysis suggested that the Fe(II) embed in the cytochrome C might serve as the catalytic center and methyl radical was responsible for the ATRP catalysis. This work explored new biocompatible catalyst for aerobic ATRP, which might open new dimension for practical ATRP and application of cytochrome C protein.

[Establishing potential habitats of Mytilopsis sallei with Maxent niche model]. / 应用Maxent建立沙筛贝潜在生境模型.

Mytilopsis sallei, an invasive alien species, has strong reproductive ability and high adaptability. It can severely endanger biodiversity of intertidal ecosystem after invasion. The intertidal zones and oyster breeding areas in some coastal areas of Guangdong Province have been severely invaded by M. sallei. To examine the potential habitat of M. sallei in China, we established a potential habitat prediction model of M. sallei using Maxent and ArcGIS method for China and global scales. The model was verified by the method of receiver operating characteristic curve (ROC) analysis and field investigation. The results showed that M. sallei could distribute with high probabili-ty in the area between North and South America, South India in Asia, Sri Lanka, the south coast of the Yangtze River in China, and in Van Dimen Bay of the southern hemisphere. In China, M. sallei mainly distributed in coastal provinces south of Shanghai. The main environmental factors affecting the suitable distribution areas for M. sallei were water vapor pressure, temperature, and solar radiation. After ROC detection, the AUC values of both the training and testing sets were 0.996, indicating that the prediction reached an excellent level. Our results provide theoretical basis for the risk assessment and management of M. sallei, and complement the potential habitat prediction of invasive species in China.

Tiny cystine stones in the gallbladder of a patient with cholecystolithiasis complicating acute cholecystitis: a case report.

Cystine stones, the main component of which is cystine, are very common urinary calculi, but are rare in the gall bladder. In animals, there has been only one report of cystine gallstones in tree shrews, and to our knowledge, this is the first report of cystine gallstones in humans.