English
Cell contamination is a headache for every researcher. When using cell culture flasks to culture cells, a little carelessness will cause contamination, resulting in the failure of previous efforts. Among many pollution sources, mycoplasma pollution is a common one. After this kind of pollution occurs, it will generally have the following manifestations:
1. The shape of the cells may not change significantly, the mycoplasma can coexist with the cells, the cell fluid will not die after contamination, and the medium generally does not become turbid;
2. Using mycoplasma-contaminated cells for experiments will seriously affect the results of the experiments, because mycoplasma inhibits cell growth; causes chromosomal aberrations; changes in cell membrane antigenicity; reduces cell viability after recovery, etc.
3. Affect the metabolism and function of the cells in the cell culture flask: the arginine in the culture medium is consumed by mycoplasma in large quantities, causing the synthesis of cellular proteins, DNA, rRNA, and mRNA obstacles; the activity of mycoplasma changes the composition of the culture medium (such as fermentation Mycoplasma degrades sugars to produce acidic substances) and affects cellular metabolism.
4. During the culture process, the cells are broken more, the pH of the medium changes obviously, and the fresh medium needs to be replaced frequently;
5. After the cells are contaminated by mycoplasma, a symbiotic system will be formed, resulting in the continuous expansion of the contamination.
There are many reasons for mycoplasma contamination in cell culture flasks, such as cross-contamination between cells; operator's mouth, skin, etc.; contamination of working environment or experimental equipment; contamination of culture medium, etc. For mycoplasma contamination, we must focus on prevention and strictly implement aseptic operations in all links.
The FAI climbed 5.9 percent year-on-year in the first 11 months of 2018, quickening from the 5.7-percent growth in Jan-Oct, the National Bureau of Statistics (NBS) said Friday in an online statement.
The key indicator of investment, dubbed a major growth driver, hit the bottom in August and has since started to rebound steadily.
In the face of emerging economic challenges home and abroad, China has stepped up efforts to stabilize investment, in particular rolling out measures to motivate private investors and channel funds into infrastructure.
Friday's data showed private investment, accounting for more than 60 percent of the total FAI, expanded by a brisk 8.7 percent.
NBS spokesperson Mao Shengyong said funds into weak economic links registered rapid increases as investment in environmental protection and agriculture jumped 42 percent and 12.5 percent respectively, much faster than the average.
In breakdown, investment in high-tech and equipment manufacturing remained vigorous with 16.1-percent and 11.6-percent increases respectively in the first 11 months. Infrastructure investment gained 3.7 percent, staying flat. Investment in property development rose 9.7 percent, also unchanged.