The Study Of Experimental Method For C.elegans Space In-orbit Culture

Caenorhabditis elegans(C.elegans)is a model organism widely used in the research of environmental toxicology,and is also a model animal commonly used in the field of space biology because its genome research is clear and some key genes are highly homologous to humans.C.elegans is fed on microorganisms under normal culture conditions and has a short life span(14-18 days).The samples obtained in the past spaceflights were mixed for several generations when analyzed after return,it was difficult to distinguish the contemporary stress effect on the space environment.We designed a method of separation and control of single nematode based on microfluidic chips,which can achieve in-orbit development and injury monitoring in space.To achieve this function,it is necessary to analyze the life support conditions of nematodes in liquid culture environment,and propose parameters for designing the in-orbit automatic control system.This study established the sterile liquid nematode culture method to meet the microfluidic chip microchannel drive requirements.The liquid culture medium was used for domestication of nematodes,and stable growth of nematodes with a life span of more than 30 days were obtained.20? was determined as the temperature for in-orbit culture,and 12?was used as the control temperature before launch.The detection standards of growth index,movement,oviposition and life span were established in the liquid culture medium.The study further analyzed the nematode's sensitivity to light and found that the cold light source was more suitable for nematode growth and development requirements.The input parameters were provided for the design of microfluidic automatic control system.In order to ensure the collection quality of nematodes in-orbit after returning to the ground,this study established the process of using cell culture bags to collect nematode progeny that would be connected to microfluidic chips,the results showed the process can support the survival and sterility needs of nematode collection during 30-day culture,and the quality of the nematode RNA obtained under this condition meets the requirements of "omics" sequencing.In order to guide the application of dauer stage nematodes in orbit to achieve long-term on-orbit culture,this study further established a method for inducing dauer stage nematodes in liquid culture system.The above research provided life-limiting parameters for realizing long-term in-orbit exposure of nematodes at different development stages in space and the development of equipment.Quality control standatds for the entire process had also been established for spaceflight launch,on-orbit and return.