Study On The Genetic Variation Characteristics Of Klebsiella Pneumoniae In Simulated Microgravity Environmen

As a kind of Gram-negative bacteria,Klebsiella pneumoniae(K.pneumoniae)is still one of the common pathogens in hospital,which seriously affects human health.The development of aerospace has led astronauts to explore space.Studies have shown that a variety of microbes can be detected inside spacecraft after spaceflight,including K.pneumoniae.The immune systems of astronauts are compromised in extraterrestrial space,making them more susceptible to microbial infections.Microgravity is the main mutagenic factor in space stations,and for this reason,the study of genetic variation patterns of microbes,especially highly resistant pathogens such as K.pneumoniae,in a microgravity environment has become one of the most pressing problems in the field of microbiology.Therefore,we have done the following studies: firstly,we successfully completed the culture of K.pneumoniae in a microgravity environment in rotating cell culture system,and studied the biological features of K.pneumoniae such as growth,morphology,biofilm formation and susceptibility to antibacterial drugs under simulated microgravity(SMG).Secondly,based on whole-genome sequencing,we systematically sequenced and analyzed the cultured samples of K.pneumoniae and detected the variant genes under SMG;Thirdly,based on RNA-Sequencing,we screened the differential gene expression of K.pneumoniae at different periods and identified the key biological pathways and differential gene expression of K.pneumoniae in response to the microgravity environment.pathways and differential gene expression.Our results showed that compared to the control group,K.pneumoniae under SMG had slower growth,thicker pods,increased biofilm formation,and altered susceptibility to various antimicrobial drugs;histological analysis showed that two metabolismrelated genes were mutated under SMG,several metabolism-related biological pathways were significantly regulated,and some genes were differentially expressed in bacterial secretion,quorum sensing,and biofilm formation.The alteration of biological features and the occurrence of genetic variation reflect the patterns and laws of genetic variation of K.pneumoniae under SMG,which is expected to provide relevant theoretical basis for safeguarding the health of astronauts and preventing underlying biosafety threats.