RT-PCR electrophorasis - (Dec/27/2015 )

              Sample cDNA’s                                         Primer pairs

1.    Ladder

2.    MM6   + (M-MLV; cDNA)                                         (GAPDH)

3.    MM6   + (M-MLV; cDNA)                                         (TNF)

4.    MM6   -  (M-MLV; no cDNA)                                   (GAPDH)

5.    MM6   -  (M-MLV; no cDNA)                                   (TNF)

6.    MM6 LPS  + (M-MLV; cDNA)                                 (GAPDH)

7.    MM6 LPS  + (M-MLV; cDNA)                                 (TNF)

8.    MM6 LPS  - (M-MLV; no cDNA)                            (GAPDH)

9.    MM6 LPS  - (M-MLV; no cDNA)                            (TNF)

10. Test cDNA positive control   (if available)           (GAPDH)

11. Test cDNA positive control   (if available)           (TNF)

12. PCR without any cDNA (negative control)         (GAPDH)

 ( see the attach file for electrophoresis results)

can any on explain the following:

1) ladder is not clear

2) in lane 4 GAPDH is expressed

3) in Lane (7.8,9.10, 11) TNF and DAPDH expressed

One word: contamination!