Construction and optimization of squalene epoxide synthetic pathway in Escherichia coli / 生物工程学报

Triterpenoids are a class of natural products of great commercial value that are widely used in pharmaceutical, health care and cosmetic industries. The biosynthesis of triterpenoids relies on the efficient synthesis of squalene epoxide, which is synthesized from the NADPH dependent oxidation of squalene catalyzed by squalene epoxidase. We screened squalene epoxidases derived from different species, and found the truncated squalene epoxidase from Rattus norvegicus (RnSETC) showed the highest activity in engineered Escherichia coli. Further examination of the effect of endogenous cytochrome P450 reductase like (CPRL) proteins showed that overexpression of NADH: quinone oxidoreductase (WrbA) under Lac promoter in a medium-copy number plasmid increased the production of squalene epoxide by nearly 2.5 folds. These results demonstrated that the constructed pathway led to the production of squalene epoxide, an important precursor for the biosynthesis of triterpenoids.

A qualitative study of caregivers of patients with esophageal cancer on nutritional care / 中国实用护理杂志

Objective To understand caregivers concerning on the nutritional status of patients with esophageal cancer after operation and to provide reference for esophageal cancer patients with postoperative rehabilitation guidance, to help nurses providing targeted health education for esophageal cancer patients. Methods A phenomenological approach was used to conduct unstructured interviews with 8 caregivers of patients with esophageal cancer in the cancer hospital.Data Data were analyzed by Colaizzi's phenomenological procedure. Results Through reading, analysis, reflection, classification and extraction,there were 3 themes: lacking of esophageal cancer related nutrition knowledge, but the belief of active acquisition is strong and behavior compliance is poor. Caregivers are positive about dietary nutrition;Caregivers have poor compliance and professionalism on behavior of dietetic care. Conclusions Doctors and nurses need to carry out elaborate diet instruction for caregivers of patients with esophageal cancer, to meet their nutritional knowledge needs, to provide a variety of effective and authoritative counseling channels, and to supervise their care behavior and promote patients rehabilitation as soon as possible.