(Adds O2 Czech, RWE,Vivendi )
Feb 27 (Reuters) - The following bids, mergers, acquisitions and disposals were reported by 2100 GMT on Friday:
** Nikon Corp, the 98-year-old Japanese company best known for its cameras, has agreed to buy British retinal imaging firm Optos Plc for 259.3 million pounds ($400 million) as it moves into the medical sector.
** O2 Czech Republic’s board of directors agreed to spin off its telecommunications infrastructure assets into a $1.9 billion firm, the fixed and mobile service operator said.
** German utility RWE said that closure of the sale of its oil and gas unit DEA to Russian tycoon Mikhail Fridman is imminent, after a media report said the date for completion will be March 1.
** In its latest effort to slash costs as commodity prices fall, Rio Tinto is letting go its energy chief and rolling its coal and uranium businesses into two other units, a move that could signal its intention to divest its coal assets.
** Australia’s Newcrest Mining Ltd said it has sold just over half of its stake in fellow Australian gold producer Evolution Mining Ltd for A$106 million ($83 million) to help it pay down debt.
** South Korean retail giant Shinsegae Group said it would not bid for a majority stake in Kumho Industrial Co Ltd , the parent of Asiana Airlines Inc, without identifying a reason for the change in plan.
** Troubled Finnish nickel miner Talvivaaran Kaivososakeyhtio Oyj said talks with potential buyers continued, but added there was “substantial uncertainty” that a deal could be found that would keep its mine running in the Northern Finland.
** Petróleo Brasileiro SA denied that it has hired JPMorgan Chase & Co to handle the sale of oil exploration licenses in deep-sea areas off the coast this year. (Compiled by Amrutha Gayathri and Kshitiz Goliya in Bengaluru)