Wall Street Roundup: The curious case of Rajat Gupta. Turning to Twitter.

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Gold: Trading now at $1,434 per ounce, unchanged from Monday. Dow Jones industrial average: Trading now at 12,167.27, up 0.6% from Monday.

On your marks. The highly anticipated trial of Raj Rajaratnam gets underway Tuesday with jury selection -- potential jurors are being asked about their attitudes toward Wall Street.

The curious case of Rajat Gupta. Andrew Ross Sorkin points out some of the oddities in the government’s pursuit of Rajat Gupta in its insider-trading investigation. Nonetheless, Gupta, the former head of McKinsey & Co., has now stepped down from two more board seats.

Bankers winning back trust. The Russian government is turning to the heads of American banks to help it drum up investments in Russian companies; meanwhile, the Bank of England has hired an old Goldman Sachs hand, suggesting that the bank’s toxic reputation may be fading.

Turning to Twitter. As commodities prices skyrocket, traders and farmers are using social-networking tools such as Twitter to keep up with the latest developments.

-- Nathaniel Popper in New York