Structure and function in the spermatozoon of Bacillus rossius. The spermatozoon of arthropoda. XIX.

Abstract

Summary The spermatozoon of Bacillus rossius is peculiar in many respects. The acrosome bears only the two outer layers, and the Golgi complex is involved in the building up of a large number of flagellar structures. In fact, it has been observed that a group of Golgi-derived cisternae analogous to the proacrosomal ones become arranged around the original 9+9+2 axoneme forming the two laminated accessory bodies and also supplying the nine outer tubules with carbohydrates. Other cisternae that migrated peripherally partially replace some plasma membrane areas. Furthermore, the Bacillus sperm represents a unique model by virtue of other characteristics more directly involved in the problematics of metabolism and motility, which are closely interdependent. These characteristics are as follows: 1. Absence of mitochondria and presence of anaerobic glycolysis alone. 2. Different categories of organelles endowed with ATPase activity cytochemically identified. These organelles are the postcentriolar region, the doublet arms, the central sheath, coarse fibers (corresponding to the zones intervening between accessory tubules), accessory laminated bodies (characteristic of the spermatozoon in Phasmoidea alone, located in the position occupied as a rule by the mitochondrial derivatives). Demonstration of ATPase activity and the morphological changes of all these structures that are protein in nature, during the different torsion states of the spermatozoon suggest that they may be endowed in some way with contractile activity. 3. The anterior region of axoneme as origin of the motion. 4. Propagation of two superimposed wave systems of different amplitude and frequencies. This phenomenon is explained as the occurrence of two different flagellar components, each responsible for the propagation of a wave system. The different frequencies are imagined to be a consequence of the ATPase catalytic characteristics; the amplitudes derive from the mechanical properties of the propagation structures. The evidence presented above suggests that the axoneme and the laminated bodies are responsible, respectively, for the propagation of the high-frequency and the low-frequency waves. As to general features of wave propagation, the involvement of contractile as well as of elastic structures has been postulated. The contractile structures are to be identified in ATPase-reacting organelles; the elastic ones may be of less definite location.