Problems with BRL 100 bp ladder

[suihuang at usa1.com]

In article <416an9$fph at overload.lbl.gov>, dmh says...
>
>....  
>I have been experiencing problems recently with the 100 bp ladder from
>Gibco-BRL. ., has anyone lately
>experienced any problems with the ladder-- particularly in certain lot numbers?
>Second, has anyone noticed differences in the mobility/resolution due to added
>NaCl?
>Thanks in advance for your responses.
>Derek
>

In a reply, Christian Beltinger reported similar problems.

I also see a smear with a 100 bp ladder from Sybtrel, Inc., especially when using 
the more sensitive dye Sybr Green I.
With EtBr the smear appears only when the gel was stained separately after 
running. When using the "EtBr-in-gel-method" (put EtBr into gel before casting), 
no such smear is visible.
Thus it might  be just a question of changing sensitivity, whethet the smear is 
visible.