Such bonds shall be signed in the corporate name of the university by the chairman of the board of trustees of the university, under the corporate seal of the university attested by the secretary of the board of trustees. Interest coupons attached to the bonds shall be signed by the facsimile signatures of such officers. Such bonds may be issued notwithstanding that any of the officials signing them or whose facsimile signatures appear on the coupons shall have ceased to hold office at the time of such issue or at the time of the delivery of such bonds to the purchaser.