. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 298 DONALD P. COSTELLO. FIGURE 4. Diagram of cross-section of a 9 + 2 flagellum, showing direction of doublet bending for a planar wave. augurated in the first doublet. The stiffness of the central singlets of a flagellum must persist in any given region for the duration of the active cycle of the wave- length. As in cilia, basal activation of doublet # 1 of the 9 + 2 flagellum will again be ineffective in producing bending, and for the same reasons. Activation of doublets #2, #3 and #4, successively, will result in the prop
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 298 DONALD P. COSTELLO. FIGURE 4. Diagram of cross-section of a 9 + 2 flagellum, showing direction of doublet bending for a planar wave. augurated in the first doublet. The stiffness of the central singlets of a flagellum must persist in any given region for the duration of the active cycle of the wave- length. As in cilia, basal activation of doublet # 1 of the 9 + 2 flagellum will again be ineffective in producing bending, and for the same reasons. Activation of doublets #2, #3 and #4, successively, will result in the propagation of bending waves out the axoneme and produce its movement in one direction (Figs. 4 and 5). Re- sistance to lateral bending of doublets #5 and #6 is then encountered as they are activated, due to their attachment to each other, and to the continuing stiffness, etc., of the central singlets. Now, however, because of the continuing length of the flagellar microtubules, the stiffening and bending waves do not terminate at the half-wavelength point, but continue moving out along the microtubules by which they are being propagated, for the full length of the axoneme. At the basal plate of the flageKar axoneme, 1/9 cycle after the activation of doub- let #6, a bending wave is initiated in doublet #7, then successively in doublets #8 and #9, reversing the direction of the beat. With the singlets still stiff, these three doublets produce a planar return stroke. So, instead of an effec- tive stroke and a recovery stroke, we have a complete planar wave propagated out the flagellum. The singlets may then relax, for the brief period between the activation of doublet #9, and the completion of the movement of the commutator around into position under doublet #1. Now, as the central singlets and doublets #l-#9, in order, are again successively activated at the base of the axoneme, a sec- ond wave, with the same characteristics, will be sent after the first. And, with the number presen
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
