Serum is a commonly used nutrient substance when culturing cells, and the quality of serum is directly related to the growth status of cells. Sometimes we will find that there are flocculent sediments in the square petg media bottles. In fact, there is no need to be too nervous when this happens. These sediments are mainly the following three types of substances:
1. Fibrin: It is a relatively large precipitate that often appears, which can reach 1-2mm and can be observed with the naked eye. Because serum is collected and processed quickly at low temperatures, some fibrinogen (the soluble precursor to flocculent fibrin) remains dissolved during processing and will Fibrin precipitates from clotting in serum bottles.
2. Calcium phosphate: It is also a common precipitate, which usually makes the serum appear turbid, and it will increase when cultured at 37°C. This deposit looks like tiny black dots under an inverted microscope, which are often mistaken for microbial contamination because they appear to be mobile due to Brownian motion.
3. Cholesterol, fatty acid esters, and some proteins: they are also common causes of precipitates in serum.
The above are the three common sediments in square petg media bottles. Generally, the sediments will not affect the cell culture, but if the cells have special needs for nutrients, the components in the sediments cannot be absorbed by the cells, which may cause the cells to grow poorly.
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.