Objective To modify the mouse model of orthotopic left lung transplantation from different perspectives, aiming to establish a simpler, faster and stabler mouse model of lung transplantation. Methods Based on preliminary modified rat model of orthotopic left lung transplantation established by our team, varying extent of modifications were made regarding the tracheal intubation, cannula preparation and anastomosis procedures of orthotopic left lung transplantation in the recipient mice. Orthotopic left lung transplantation in 40 mice were performed by an operator with microsurgical experience. The dissection of the recipient's hilar structure was carried out at the plane of the hilar clamp model within the reverse-view, and the three branches (left main bronchus, pulmonary artery and pulmonary vein) of the pulmonary hilum were anastomosed in turn by the "pendulum" anastomosis method. The operation time of each procedure was recorded. The recipient mice were sacrificed at postoperative 2 weeks, and the incidence of postoperative complications was recorded. Results Lung transplantation was successfully completed in 40 mice, with no bronchial and vascular tearing or twisting, and no bleeding at the anastomosis site. The overall cardiopulmonary procurement time was (10.7±1.5) min, cannula preparation time was (16.2±1.5) min, cold ischemia time was (25.1±2.4) min, warm ischemia time was (19.4±1.6) min, and the total operation time was (57.2±2.9) min, respectively. During the follow-up from 6 to 14 days after surgery, one recipient mouse died of pleural effusion, probably caused by infection. No pneumothorax, thrombosis or atelectasis was found in the remaining recipient mice during postoperative follow-up. Conclusions The modified mouse model of orthotopic left lung transplantation based on "pendulum" anastomosis of the reverse-view plane possesses multiple advantages of short operation time, high success rate and few complications, which is expected to become an alternative model of studying pathological changes after lung transplantation and worthy of further application.

Lycopene plays a crucial role in the biosynthesis pathway of 2-methyl-derythritol-4-phosphate (MEP) and mevalonic acid (MVA). It is a representative product of isoprenoid family, and a typical product of multi-enzyme catalytic reaction in organism. In this paper, we first introduced the general regulation methods in multi-enzyme synthesis reaction, including the construction of multi gene co-expression plasmid, gene order regulation, promoter and ribosome binding site regulation, gene knockout and replacement, aiming at the optimization strategies of multi-enzyme catalytic reaction in lycopene synthesis pathway. Meanwhile, we introduced several new regulation methods in multi-enzyme reaction, including multi-fragment assembly technology, artificial scaffold self-assembly methods and so on. At last, we summarized the application of these multi-enzyme regulation methods in lycopene synthesis. These methods provide a great inspiration and research foundation for the construction of lycopene-producing strains with high yield.