TABLE 3.
Locomotor responses to shifts from 12:12 LD cycles to <24- or >24-hr cycles
| Behavioral categories after shift to 9:9 LD, mean period(s) ± SEM
|
|||||
|---|---|---|---|---|---|
| Genotype | N rhy/N tested (% rhy) | One periodic component: ∼24hr | One periodic component: ∼8 hr | Two periodic components | Ambiguous |
| norpAP24 | 39/44 (89) | NA | 18.1 ± 0.1 | NA | NA |
| cry01,02, or03 | 54/60 (90) | 23.5 ± 0.1 (11% of rhy) | 18.4 ± 0.2 (63% of rhy) | 18.0 ± 0.0 and 22.6 ± 0.3 (19% of rhy) | NA (7% of rhy) |
| norpAP24 cry01,02, or03 | 104/107 (97) | 23.6 ± 0.0 (69% of rhy) | 18.0 ± 0.9 (4% of rhy) | 19.8 ± 0.2 and 23.6 ± 0.1 (15% of rhy) | NA (12% of rhy) |
| Behavioral categories after shift to 13:13 LD, mean period(s) ± SEM
| |||||
|---|---|---|---|---|---|
| Genotype | N rhy/N tested (% rhy) | One periodic component: ∼24 hr | One periodic component: ∼26 hr | Two periodic components | Ambiguous |
| norpAP24 | 20/21 (95) | NA | 26.0 ± 0.0 (100% of rhy) | NA | NA |
| cry01or02 | 43/43 (100) | NA | 25.8 ± 0.0 (100% of rhy) | NA | NA |
| norpAP24 cry01or02 | 38/38 (100) | 24.2 ± 0.1 (42% of rhy) | 25.6 ± 0.1 (18% of rhy) | 22.4 ± 0.1 and 25.1 ± 0.2 (13% of rhy) | NA (26% of rhy) |
| Behavioral categories after shift to 14:14 LD, mean period(s) ± SEM
| ||||||
|---|---|---|---|---|---|---|
| Genotype | N rhy/N tested (% rhy) | One periodic component ∼24 hr | One periodic component ∼28 hr | Two periodic components | One periodic component with phase shift | Ambiguous |
| norpAP24 | 19/21 (91) | NA | 27.8 ± 0.1 (100% of rhy) | NA | NA | NA |
| cry01,02, or03 | 22/23 (96) | NA | 27.7 ± 0.1 (100% of rhy) | NA | NA | NA |
| norpAP24 cry01,02, or03 | 122/129 (95) | 24.2 ± 0.1 (20% of rhy) | 27.0 ± 0.0 (3% of rhy) | 23.5 ± 0.1 and 26.1 ± 0.1 (28% of rhy) | 25.7 ± 0.1 (13% of rhy) | NA (36% of rhy) |
Flies were exposed to 12:12 LD cycles for 5 days, then shifted to the novel LD cycles indicated for 7–8 days, followed by monitoring locomotion in DD (data from the latter condition not tabulated, but see Figure 4). Each postshift locomotor record was subjected to observer-blind analysis to evaluate its periodic component(s), if any, including whether or not the fly had resynchronized to the new cycle duration. Periods were determined by the straight-edge slope procedure noted in materials and methods.
Examples of behavioral responses in the 12:12 →14:14 test are in Figure 4. The “one periodic component with phase shift” outcome refers to the following: flies that displayed one periodic component, running with a certain period (always <28 hr) until the time when such individual flies “should” be active in the dark if their behavior continued with the same period; but starting at that point, an individual behaving in this category was not active during the entire 14 hr of DD; after lights-on, locomotion commenced again and continued to be periodic, although this new component was shifted relatively to the first such component (see Figure 4F).
Ambiguous, referring either to (i) locomotor patterns that were so messy (involving, for example, three putatively separate rhythmic components per actogram) that no proper categorization was possible; or (ii) to solid and simple periodic postshift outcomes that were judged not to be near enough to either 24 hr or to the novel LD cycle durations; specifically, in the 9:9 test, 3 of the 12 NA flies gave 22.5-hr periods; in 13:13, 7 of 10 NA's gave 25-hr periods; in 14:14 out of 44 NA's 1 fly gave a 25-hr period, 3 gave a 25.5-hr period, 19 gave a 26-hr period, and 12 gave a 26.5-hr period; NA, not applicable (meaning either that no behavioral outcomes fell into that category or that some did, but a particular period value could not be specified because of ambiguities among individuals); rhy, rhythmic; SEM, standard error of the mean.