ABSTRACT
Cancer and cardiovascular diseases are the two major causes of death worldwide. The application of anti-tumor drugs has significantly improved the prognosis of patients, the cardiovascular toxicity caused by the application of them has become an important factor affecting the survival and prognosis of cancer patients. Therefore, the prevention and treatment of cardiovascular toxicity related to cancer treatment is increasingly important. The cardiovascular toxicity associated with anti-tumor drugs exhibits different clinical manifestations and involves multiple pathological mechanisms. This article reviews the current research progress from the perspective of the characteristics, molecular mechanisms and prevention and treatment strategies of cardiovascular toxicity caused by cancer drugs.
ABSTRACT
Saponin is a kind of complex compounds with triterpenoid or spiral aglycones.Natural saponins are used as substrates,and many novel compounds are obtained by biotransformation technology. Especially, converted products of saponins with strong activities provide valuable lead compounds for the research and development of new drugs. Saponins can be divided into triterpenoid saponin and steroidal saponin according to the structure of the mother nucleus. There are about 89 reported saponin components,including 56 triterpenoid saponins and 33 steroidal saponins. Biological enzyme catalysis,microbial transformation and intestinal microflora transformation are the main bioconversion technologies and key development directions of saponins. The research and optimization technology of biological enzyme and microbial transformation of saponins are the effective methods to prepare active secondary saponins. The biotransformation reaction of saponins mainly includes hydrolysis,redox and rearrangement,resulting in the formation of aglycones,secondary glycosides and their derivatives. The hydrolysis of saponin sugar chains was the main biological transformation pathway, and could generate a number of secondary saponins with less glycosyl groups. The secondary saponins could be absorbed into blood and become real active ingredients in body. Preparation of rare secondary saponins,discovery of lead compounds and development of new drugs are the main directions of biotransformation of saponins. The studies on the metabolism and mechanism of natural saponins by microbial and intestinal microbial biotransformation will also become hotspots. According to relevant papers at home and abroad,the researches on transformation technique,transformation approach and transformation reaction of saponins from natural products in the past thirty years were summarized, and the prospects of research and development were also analyzed to provide scientific basis for further study and comprehensive utilization of these conversion products.
ABSTRACT
The tandem expression vector can effectively increase the expression level and structure stability of the target peptides(protein)with small size of molecular,and avoid toxicity towards host cell from some toxic peptides product,therefore,this approach is widely applied in biotechnology.The four construction methods of tandem expression plasmid including asymmetric and complementary cohesive ends,directional adapter,isocaudarners,and tandem expression cassette were reviewed in terms of protocol,characteristic and applicable field.In addition,selection principles from various construction methods of tandem plasmid were reviewed in terms of efficiency,accuracy and product cleavage.
ABSTRACT
The structure, reaction mechanism and molecular biology of Leuconostoc mesnteroides dextransucrase are reviewed.