Hydraulic control apparatus includes a belt-drive CVT, a pressure regulator valve regulating the oil pressure produced by an oil pressure source, a controller programmed to develop a transmission control signal, a transmission actuator driven based on the signal, and a transmission control valve actuated by the actuator. The disclosure can protect the amplifiers which are connected downstream thereof or the electronic evaluation system from overloading. The present invention provides a luciferin in which the benzothiazole ring moiety has been modified at the 7-position, a luciferin analog in which the benzene ring moiety has been modified at the 6-position, and a luciferin analog in which the 6–2-naphthalenyl moiety has been modified at the 5-position.