European shares turn lower as commodities, Portugal weigh

* FTSEurofirst 300 down 0.4 pct, Euro STOXX 50 down 0.5 pct

* Vodafone rises after strong results, Vallourec drops

* Portuguese stocks underperform on political uncertainty

By Danilo Masoni

MILAN, Nov 10 (Reuters) - European shares reduced gains toturn lower by mid-morning on Tuesday as losses among commoditystocks and political uncertainty in Portugal more than offset asolid earnings reports from Vodafone.

The pan-European FTSEurofirst 300 was down 0.4percent, giving up initial gains, and the euro zone's blue-chipEuro STOXX 50 index was down 0.5 percent.

Shares had opened higher on the back of a weaker euro, whichmakes investment in the region more attractive, but pared gainsas commodities stocks extended falls and U.S. futures indicate alower open at Wall Street.

The European mining index was the top sectoralfaller with a drop of 1.4 percent, as London copper prices movedcloser to a six-year low on Tuesday amid a firmer dollar andprolonged economic weakness in top metals consumer China.

Roberto Lottici, a fund manager at Italy's Ifigest, saidexpectations of central bank support was providing a floor toEuropean equities but suggested to be selective on single stocksand consolidate gains as the year end approaches.

Vallourec fell more than 9 percent after reportinga third-quarter loss against a backdrop of falling demand fromits oil and gas customers and said it did not expect marketconditions to improve in the short-term.

But Vodafone rose more than 4 percent after theBritish phone group reported a better-than-expected accelerationin second-quarter revenue growth, helping it nudge its annualexpectations towards the top of its guidance.

Dialog Semiconductor was another bright spot,rising 5.3 percent, after activist hedge fund Elliott discloseda 2.9 pct stake in the German chipmaker and opposed theacquisition of U.S. peer Atmel.

Portugal's PSI 20 index fell 2.3 percent asleftwing parties looked set to oust a minority centre-rightgovernment on Tuesday in a parliamentary vote, part of a driveto set up their own Socialist-led administration they hope willput an end to years of harsh austerity.

"Events unfolding in Portugal are especially closely watchedbecause their much larger neighbour Spain will also be holdingelections in late December which depending on the outcome couldpush the Eurozone back into a crisis," said Peregrine & Blacksales trader Markus Huber. (Reporting by Danilo Masoni; Editing by Tom Heneghan)