In your lecture about gel electrophoresis with protein gels, as well as online, the anode is labeled with a (+) and the cathode is labeled with a (-). Is it a typing error, or is a different convention being used?
In an electrolytic cell, the positive electrode is the anode. That is the terminology we are following. In any case, we will always try to specify the positive electrode or negative electrode in addition to or instead of using the words anode or a cathode.