Spinosad represents a new class of insecticides produced by Saccharopolyspora spinosa. To understand the transcription of the spinosad biosynthetic gene cluster, two promoter detection plasmids based on different reporter genes were constructed and used to detect 9 promoters in the spinosad biosynthetic gene cluster. In addition, the temporal transcriptional profiles of the corresponding genes controlled by the 9 promoters, together with 4 genes outside of the spinosad cluster but are required for the synthesis of sugars in spinosad, were examined by real-time PCR. The results indicate that the 9 spinosad biosynthetic genes were highly expressed at the stationary phase, which coincides with the accumulation of spinosad in the fermentation broth. Of particular note is that the transcription of the 4 sugar synthetic genes showed higher level at the exponential phase, suggesting the expression of sugar synthetic genes is not correlated with the spinosad synthetic genes. The data suggest that spinosad biosynthesis could be improved by engineering the expression pattern of the sugar synthetic genes that lie outside the spinosad gene cluster.
Drug Combinations ; Insecticides ; metabolism ; Macrolides ; metabolism ; Multigene Family ; Plasmids ; Promoter Regions, Genetic ; Real-Time Polymerase Chain Reaction ; Saccharopolyspora ; genetics ; metabolism

Objective:To investigate the effect of enteral nutrition on hematological complications in children with malignant solid tumors during chemotherapy.Methods:A total of 103 children with malignant solid tumor admitted to our hospital from March 2020 to December 2020 were enrolled in the study. The children were randomly divided into enteral nutrition group ( n=51) and control group ( n=52). Children in enteral nutrition group were given enteral nutrition support on the basis of routine diet, while children in control group were only given routine diet. The levels of leukocytes, neutrophils, hemoglobin and platelets in peripheral blood of children during chemotherapy were analyzed. The incidence of infection and the transfusion of red blood cells and platelets after chemotherapy were documented and compared between two groups. Results:The levels of white blood cells, neutrophils, hemoglobin and platelets before chemotherapy were significantly higher than those after chemotherapy both in enteral nutrition group ( Z=-5.91, -5.59, -5.54, -5.66, all P<0.05) and in control group ( Z=-6.14, -5.84, -5.75, -4.75, all P<0.05). The overall hemoglobin levels in enteral nutrition group before and after chemotherapy was significantly higher than those in control group ( t=5.68, 5.62, P<0.05), and there were no significant differences in the levels of white blood cells, neutrophils and platelets between the two groups before chemotherapy ( Z=-0.71, -0.12, -1.29, all P>0.05) and after chemotherapy ( Z=-0.39, -0.86, -0.94, all P>0.05). Compared with the control group, the degree of anemia during chemotherapy was significantly improved in enteral nutrition group (χ2=10.45,6.12, all P<0.05), but there was no significant difference in the reduction degree of white blood cells, neutrophils and platelets between the two groups (before chemotherapy: χ2=1.17, 0.10, 0.49; after chemotherapy: χ2=0.18, 1.10, 0.97, all P>0.05). The number of children receiving red blood cell transfusion in enteral nutrition group was significantly lower than that in control group (χ2=14.06, P<0.05), and there was no significant difference in the number of children with infection and platelet transfusion between the two groups (χ2=1.20, 0.29, all P>0.05).There was no significant difference in the duration of neutrophil deficiency between enteral nutrition group and control group ( t=-1.75, P>0.05). Conclusion:Enteral nutrition support can significantly improve the hemoglobin level in children during chemotherapy, effectively alleviate the severity of anemia, and reduce the incidence of red blood cell transfusion after chemotherapy, which has high clinical application value.