Except as otherwise provided by act of the legislature, the state educational institutions are separate state agencies and state institutions and shall be controlled by and operated and managed under the supervision of the board of regents. For such control, operation, management or supervision, the board of regents may make contracts and adopt orders, policies or rules and regulations and do or perform such other acts as are authorized by law or are appropriate for such purposes, except that no state educational institution, or campus thereof, shall be closed, combined or merged with any other state educational institution, for administrative or management or other purposes, except as specifically authorized by appropriations or other act of the legislature.