Unsuccessfull DNA extraction - Extraction of Gram + bacteria (Sep/15/2004 )

I have extracted DNA from Oenococcus oeni and When I've measured O.D. I got realyy good values but when I made it run in an agarose gel I realized I didn't have DNA (except for one sample) ¿What am I measuring with my 260 O.D.?

Genomic DNA will typically not run on a gel (it's far too large), but rather show as a bright regions in or near the wells where it is loaded. That might be your problem.

Another possibility is that you have used a phenol chloroform extraction, and are measuring contaminating phenol at 260 nm.