Fig. 2. uif mutant first instar larvae have defects in tracheal inflation and damaged tracheal tubes.

(A–D) Brightfield photomicrographs of (A)w¹¹¹⁸, (B) uif^2B7, (C, D) btl-Gal4/UAS-uifRNAi, (E) UAS-uifRNAi/+; da-Gal4/+, (F) en-Gal4/UAS-uifRNAi newly hatched first instar larvae. All animals are depicted with anterior to the left. Refracted light makes the inflated trachea clearly visible in the wild type larva and shows that the tracheae of uif mutant animals are partially to completely uninflated. The boundary of inflated/uninflated trachea are marked by arrows in B, C and E. Note that en>uifRNAi larvae have normally inflated tracheae (F). (G–J) Differential Interference Contrast micrographs of dorsal tracheal trunks in w¹¹¹⁸ (G) and uif^2B7 (H–J) newly hatched first instar larvae. Note the regular diameter of the inflated dorsal trunk in the wild type larva as it gradually tapers towards the anterior over 6 segments, and contrast that to uif mutant tracheae that appear twisted or crushed and show discontinuous regions that are uninflated. Scale bars = 50µm.