Kekst, the PR agency that made its name advising on takeovers, was on the receiving end today as it sold out to French advertising firm Publicis. Founded by Gershon Kekst in 1970, the firm is famed for advising on deals like the lenghty, frenzied battle for RJR Nabisco, the leveraged buyout in the 1980s which was immortalized in Barbarians at the Gate (Kekst’s client in that deal was buyout giant Kohlberg Kravis Roberts).

Barbarians authors Bryan Burrough and John Helyar put Kekst’s influence this way in the book:

“For years Wall Street public relations has been dominated by a single firm, Kekst & Co., and its well-connected founder, Gershon Kekst. Kekst spokespeople can be found in every major takeover, dishing dirt on that day’s enemy alongside their formal, routine press releases. It was on Gershon Kekst’s advice that Kohlberg Kravis managed to stay out of the headlines for nearly a decade.”

The Publicis/Kekst deal size wasn’t disclosed, but that’s hardly surprising. Better known for what he doesn’t say than what he does, Gershon Kekst was described in a lengthy 1996 profile by Institutional Investor as having “an aura of mystery. His firm does not trade on its roster of clients or even talk about them. Even competitors who have worked opposite his firm on deals know little about Kekst. “Have you seen him?” one asks. “What does he look like?”.

According to the latest figures from M&A research firm Mergermarket, Kekst is indeed still the most powerful advisor on Wall Street, advising on 67 deals in the US worth $108 billion.

The Wall Street Journal leads with a piece saying Microsoft is preparing a new bid for Yahoo’s search business that could bring on board media giants Time Warner and News Corp and effectively lead to Yahoo’s breakup. The talks are preliminary and unlikely to result in a deal with Yahoo, the paper said, and although it all seems whimsical, Yahoo shares jumped more than 6 percent in early trade. Yahoo rejected a $47.5 billion takeover offer by Microsoft, and earlier this week questioned whether the software maker was ever serious about a full-scale merger. Carl Icahn, who is running a slate of directors to replace Yahoo’s board and has called for the removal of Chief Executive Jerry Yang, has met with Microsoft, which is encouraging him to press his proxy contest as a way to keep pressure on Yahoo to enter into a deal that would lift its share price, the paper said, citing people familiar with the matter.

British events organizer and publisher Informa said it was considering a 2.15 billion pound ($4.3 billion) bid approach from a consortium of private equity firms, sending its shares 10 percent higher. Informa said in a statement that Providence Equity, The Carlyle Group and Hellman & Friedman had made a bid proposal of 506 pence a share on June 26. “Discussions continue to be at an early stage and there can be no certainty that an offer will be made,” it said. When news emerged last month that the equity firms were working on a bid for the media company, the shares showed only modest gains as analysts questioned whether a deal would succeed in the current tight credit markets.

The markets took down another deal yesterday. Blaming grim market conditions Blockbuster abandoned its $1.3 billion offer to buy electronics retailer Circuit City. Shares of the video rental chain jumped more than 7 percent in extended trade after the news while Circuit City’s shares fell 1.6 percent, after declining nearly 12 percent at Tuesday’s close — hitting their lowest point in two decades. Speculation that a potential deal with Blockbuster would not happen gained ground after Circuit City posted a wider quarterly loss and cut its dividend in June.

France Telecom said it was seeking acquisitions that would be smaller than its failed $40 billion bid for TeliaSonera but declined to comment on a possible cash return to shareholders. France Telecom has repeatedly said it is aiming to make acquisitions in emerging markets in Africa and Asia. After becoming a majority shareholder in Kenya Telecom, the French operator is eyeing stakes in Ghana Telecom, Algerie Telecom and Vietnam’s Mobifone. “The matter is closed and definitely closed,” France Telecom Chief Executive Didier Lombard told a telecoms conference organized by Les Echos newspaper, referring to its failed bid for Nordic operator TeliaSonera. “We will make more modest things in the coming months,” he said.

More deals of the day:

* Biotechnology firm Maxygen said a unit of Germany’s Bayer AG has agreed to buy its hemophilia program assets in a deal valued at $120 million, including a potential milestone payment of $30 million.

* Glenmark Pharmaceuticals has bought seven drug brands in Poland from Iceland’s Actavis and its Polish affiliate Biovena, expanding the Indian firm’s presence in Europe.

* British Airways has agreed to buy small French business airline l’Avion for 68 million euros ($107.3 million) and it will become part of its new OpenSkies unit, they said in a joint statement.

* Auto parts maker Amtek Auto is in preliminary talks to buy German light metal castings maker KSM Castings to consolidate its business in the European market, a source close to the development told Reuters.

* Jiuquan Iron and Steel Group, China’s No. 16 steelmaker, plans to inject assets worth 30 billion yuan ($4.38 billion) into a joint venture with a Kazakhstan iron miner, Jiugang’s listed unit said.

* Diversified manufacturer Johnson Controls said it would form a joint venture to acquire the interior products assets of bankrupt auto parts maker Plastech Engineered Products.

* Chesapeake Energy and Plains Exploration & Production said they have entered into a joint venture in north Louisiana and east Texas.

* Microsoft said it had agreed to buy Powerset, a start-up that is working on a new class of Web search that relies on insights from linguistics rather than simple keyword strings.