Tokyo stocks opened lower Monday as investors locked in gains following the benchmark Nikkei index’s sharp jump late last week on expectations of smaller interest rate hikes in the United States. In the first 15 minutes of trading, the 225-issue Nikkei Stock Average fell 128.00 points, or 0.45 percent, from Friday to 28,135.57. The broader Topix index was down 10.32 points, or 0.52 percent, at 1,967.44. On the top-tier Prime Market, decliners were led by construction, information and communication, and precision instrument issues. At 9 a.m., the dollar fetched 139.59-62 yen compared with 139.0…