(ShareCast News) - The FTSE 250 was down 0.57% as oil companies continued to feel the pain of the impact of lower prices on the bottom line.With FTSE 100 index heavweight BP reporting a slump in profits, oil and gas producers in the midcap index fell sharply in sympathy as they prepare for a long period in a lower oil price environment.Leading the fallers was Evraz, which is challenging a rescue plan of its South African steel maker, Evraz Highveld Steel and Vanadium. The court challenge could scupper the sale of Highveld to Hong Kong-based International Resources. Evraz shares were down 7.42% on the news.Nostrum Oil and Gas fell after lowering its full-year production guidance due to unexpected repair work on a pipeline overrunning and reported a fall in production during the first nine months of 2015 that also will see revenue almost halve.Shares in Vedanta Resources fell, as the group continued to be hampered by the worlwide weakness in oil and gas prices.In the three months to the end of September, the FTSE 250 group said its pre-tax profit tumbled 40.9% year-on-year to 9.74bn rupees (£97.7m), while net sales slumped 16% to 163.49bn rupees.On the positive side, shares in internet and phone group TalkTalk rose after the company said there was little chance customers' money could be taken after its computer systems were hacked. News that a 15 year-old boy has also been arrested in connection with the incident cheered investors.Packaging group DS Smith rose after the company said trading for the half year ending 31 October has been in line with its expectations, with good volume growth, while margins, return on average capital employed and earnings per share continue to show strong growth.FTSE 250 - RisersTalkTalk Telecom Group (TALK) 257.50p +14.29%AO World (AO.) 162.00p +3.71%OneSavings Bank (OSB) 370.70p +2.66%Smith (DS) (SMDS) 394.30p +2.20%CLS Holdings (CLI) 1,841.00p +2.11%Ted Baker (TED) 3,000.00p +1.97%UDG Healthcare Public Limited Company (UDG) 467.00p +1.46%Dignity (DTY) 2,294.00p +1.37%Just Retirement Group (JRG) 163.80p +1.36%Cineworld Group (CINE) 592.00p +1.28% FTSE 250 - FallersEvraz (EVR) 81.75p -7.42%Nostrum Oil & Gas (NOG) 449.60p -6.16%Hunting (HTG) 362.80p -5.69%Premier Oil (PMO) 68.20p -5.54%Petra Diamonds Ltd.(DI) (PDL) 81.60p -5.39%Vedanta Resources (VED) 473.50p -5.00%Drax Group (DRX) 266.00p -4.90%Weir Group (WEIR) 1,039.00p -4.77%Tullow Oil (TLW) 195.30p -4.50%Amec Foster Wheeler (AMFW) 709.50p -4.25%