Please help me with the phrase "take on"

That’s the question Forbes has been asking for five years. Forbes, whose mother is Chilean, heads an activist group called the Council for United Latinos. It’s a tiny operation run on a shoestring out of a small office in East Los Angeles.

Forbes is a staunch conservative who once was Pat Buchanan's press secretary. The group he runs now may be small, but it’s had a big impact: He has taken on — and embarrassed — major hospital chains all over the country for using tough tactics on the uninsured.

What's the meaning of take on? 

Question 1:

Does that mean that make other people accept major hospital chains all over the country for using tough tactics on the uninsured.

I

Question 2:

Who is embarrassed?

The hospitals???????

Thanks for your help.

Mister Micawber wrote:

1-- No.  Take on = contend against an opponent in a sport, game, or battle. 2-- the hospital chain companies

Oh, I see.

Thanks a lot.