Pre-treatment with exogenous dopamine restores normal locomotion to <i>cat-2</i> but not <i>dop-3</i> or <i>goa-1</i> mutants.

<p>The average (A) standard deviations of speed measurements within individual tracks, (B) magnitude (root mean square) of accelerations, and (C) acceleration peaks for animals on a bacterial lawn. The average (D) standard deviations of speed measurements within individual tracks, (E) magnitude (root mean square) of accelerations, and (F) acceleration peaks for DA pre-treated animals on a bacterial lawn. p-values for differences between dopamine-treated and untreated animals of the same genotype were calculated using two-way ANOVA. Tracks were first grouped by average speed. Each bin is 0.03 mm/sec wide. Error bars, SEMs. (wild-type n = 120 no dopamine, 131 DA pretreated animal tracks; <i>cat-2(n4547)</i> n = 107, 139; <i>dop-3(vs106)</i> n = 122, 128; <i>goa-1(n1134)</i> n = 162, 150; all tracks >30 sec)</p

While mutations in <i>dop-1</i> fail to suppress <i>dop-3</i> speed fluctuations, <i>dop-3</i> genomic constructs do, regardless of the promoter used.

<p>The average standard deviations of speed measurements within individual tracks for (A) wild-type animals, mutant animals, and (B) transgenic strains on a bacterial lawn. p-values for differences between standard deviation curves for each genotype were calculated using two-way ANOVA. Tracks were first grouped by average speed. Error bars, SEMs. (A: wild-type n = 934 tracks; <i>dop-3(vs106)</i> n = 941; <i>dop-1(vs100)</i> n = 1045; <i>dop-1(vs100) dop-3(vs106)</i> n = 887. B: wild-type n = 934 tracks, <i>dop-3</i> cDNA transgenic n = 853, <i>dop-3</i> genomic transgenic n = 861, P<i>_{unc-17::dop-3}</i> genomic transgenic n = 791, P<i>_unc-47dop-3</i> genomic transgenic n = 911, P<i>_tax-4::dop-3</i> genomic transgenic n = 1005, P<i>_gcy-5::dop-3</i> genomic transgenic n = 917. all tracks >30 sec).</p

Wild-type <i>C. elegans</i> locomotion assayed using an automated locomotion tracking system.

<p>(A) A speed recording of an individual worm. (B) Frequency distributions of instantaneous speed recordings of animals in the off-bacteria, well-fed on-bacteria, and food-deprived on-bacteria conditions. Each bin is 0.006 mm/sec wide. (C) Average speeds of animals in each condition. (D) Average speeds of animals as measured by manually counting body bends over 20 sec intervals. Average (E) standard deviations and (F) coefficients of variation of speed measurements within individual tracks for well-fed and food-deprived animals. p-values for differences between well-fed and food-deprived data curves were calculated using two-way ANOVA. Tracks were first grouped by average speed. Each bin is 0.0075 mm/sec wide. Error bars, SEM. (B, C, E, F: n = 1510 off-food, 1174 well-fed, 967 food-deprived animal tracks, mean track length was 53 sec in the automated assay; D: n = 528 off-food, 508 well-fed, 642 food-deprived animals assayed manually).</p

Mutation of <i>mod-5</i> suppresses the hyperactivity but not the large speed fluctuations of <i>cat-2</i> mutants.

<p>(A) Average speeds of wild-type and mutant animals tested in the well-fed on-bacteria and food-deprived on-bacteria conditions. (B) The average standard deviations of speed measurements within individual tracks for animals on a bacterial lawn. p-values for difference in average speeds were calculated using Student's T-test. p-values for differences between standard deviation curves for each genotype were calculated using two-way ANOVA. Tracks were first grouped by average speed. Error bars, SEMs. (A: wild-type n = 120 well-fed, 109 food-deprived tracks; <i>cat-2(e1112)</i> n = 123, 96; <i>mod-5(n3314)</i> n = 58, 53; <i>mod-5(n3314) cat-2(e1112)</i> n = 83, 51; B: wild-type n = 233 tracks; <i>cat-2(e1112)</i> n = 131; <i>mod-5(n3314)</i> n = 219; <i>mod-5(n3314) cat-2(e1112)</i> n = 90, all tracks >30 sec)</p

<i>cat-2</i> mutants achieve greater peak acceleration, resulting in large fluctuations in the speed within tracks.

<p>The average (A) standard deviations of speed measurements within individual tracks, (B) magnitude (root mean square) of accelerations, (C) duration of accelerations, and (D) acceleration peaks for animals on a bacterial lawn. p-values for differences between data curves for each genotype were calculated using two-way ANOVA. Tracks were first grouped by average speed. Each bin is 0.03 mm/sec wide. Error bars, SEMs. (wild-type n = 358 tracks; <i>cat-2(n4547)</i> n = 262 tracks, all tracks >30 sec)</p

The locomotion rates of <i>cat-2</i> mutants were more variable than those of wild-type animals.

<p>(A) Frequency distributions of instantaneous speed recordings of <i>cat-2(n4547)</i> mutants in each condition. Each bin is 0.006 mm/sec wide. Wild-type frequency distribution outlines are overlaid for comparison. The standard deviations of speed recordings in the well-fed and food-deprived conditions were 0.037 and 0.029 mm/sec for wild-type animals and 0.054 and 0.061 mm/sec for <i>cat-2</i> mutants. (B) Frequency distributions of average speeds of individual animals in the well-fed on-bacteria and food-deprived on-bacteria conditions. Each bin is 0.015 mm/sec wide. The standard deviations of average speeds of individual animals in the well-fed and food-deprived conditions were 0.031 and 0.023 mm/sec for wild-type animals and 0.047 and 0.054 mm/sec for <i>cat-2</i> mutants. (C) The 15 longest wild-type and <i>cat-2(n4547)</i> speed traces with average velocities of 0–0.06 mm/sec and 0.12–0.18 mm/sec overlaid. (A–B: wild-type n = 204 well-fed on-bacteria, 201 food-deprived on-bacteria animal tracks; <i>cat-2</i> n = 198, 158, all tracks >20 sec)</p

<i>n4547</i> is a deletion allele of the tyrosine hydroxylase gene <i>cat-2.</i>

<p><i> n4547</i> contains a 1007 bp deletion that removes the first, second, and third exons of the <i>cat-2</i> gene</p

The distribution of mass densities of populations of <i>C.elegans</i> can be measured through isopycnic centrifugation in linear Percoll™ gradients.

<p>(A) Image of a typical Percoll™ centrifugation medium, with density-standard beads. (B) Plot of the height of the beads versus their intrinsic densities. Each point in the plot is an average of seven measurements, error bars are within the size of the points on the graph. (C) Typical image of cold-immobilized worms, (here, immediately after the L4/adult molt), after centrifugation in the gradient. (D) Distribution of densities of the worms in (C). The red line shows a Gaussian fit to the data.</p

Changes in the distribution of mass densities of adult <i>C.elegans</i> subjected to caloric restriction.

<p>Each panel shows the distribution of densities of well-fed and starved worms at the indicated times. 0 hour corresponds to the time point immediately after the L4/adult molt. The red lines are Gaussian fits to the data and the numbers indicate the location of the peak(s) in the distributions.</p

Demonstration of a density-based assay.

<p>(A) Worms grown on agar plates without drugs (control). The distribution of densities was unimodal. (B) Worms grown on agar plates with one lawn of bacteria containing Ivermectin. The distribution of densities after six hours was bimodal. Red lines are Gaussian fits to the data. (C) Composition of the worms extracted from the lower band (not exposed to drug) and upper band (exposed to drug). Worms in the lower band had approximately half the glycogen content of worms in the upper band, consistent with a starvation-like response.</p