Except as otherwise herein provided, no member or employee of the board shall have any direct interest in the income, gains or profits of any investments made by the board, or receive any pay or emolument for services in connection with any investment. No member or employee of the board shall become an endorser or surety, or in any manner an obligor for money loaned or borrowed from the system. A violation of any of these restrictions shall constitute a Class 4 felony.