The initiator caspase Dronc is the only Drosophila caspase that contains a caspase activation and recruitment domain (CARD). Although Dronc has been implicated as an important effector of apoptosis, the genetic function of dronc in normal development is unclear because dronc mutants have not been available. In an EMS mutagenesis screen,we isolated four point mutations in dronc that recessively suppress the eye ablation phenotype caused by eye-specific overexpression of hid. Homozygous mutant dronc animals die during pupal stages; however, at a low frequency we obtained homozygous adult escapers. These escapers have additional cells in the eye and wings that are less transparent and slightly curved down. We determined that this is due to lack of apoptosis. Our analyses of dronc mutant embryos suggest that dronc is essential for most apoptotic cell death during Drosophila development, but they also imply the existence of a dronc-independent cell death pathway. We also constructed double mutant flies for dronc and the apoptosis inhibitor diap1. dronc mutants can rescue the ovarian degeneration phenotype caused by diap1 mutations, confirming that dronc acts genetically downstream of diap1.

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Caspases are essential components of the apoptotic machinery in both vertebrates and invertebrates. Here, we report the isolation of a mutant allele of the Drosophila effector caspase drICE as a strong suppressor of hid-(head involution defective-) induced apoptosis. This mutant was used to determine the apoptotic role of drICE. Our data are consistent with an important function of drICE for developmental and irradiation-induced cell death. Epistatic analysis suggests that drICE acts genetically downstream of Drosophila inhibitor of apoptosis protein 1 (Diap1). However, although cell death is significantly reduced in drICE mutants in all assays, it is not completely blocked. A double-mutant analysis between drICE and death caspase-1 (dcp-1), another effector caspase, reveals that some cells (type I) strictly require drICE for apoptosis, whereas other cells (type II) require either drICE or dcp-1. Thus, these data demonstrate a barely appreciated complexity in the apoptotic pathway, and are consistent with current models about effector caspase regulation in both vertebrates and invertebrates.

A macroporous silica with azimuthally shifted double-diamond frameworks has been synthesized by the self-assembly of an amphiphilic ABC triblock terpolymer poly(tert-butyl acrylate)-b-polystyrene-b-poly(ethylene oxide) and silica source in a mixture of tetrahydrofuran and water. The structure of the macroporous silica consists of a porous system separated by two sets of hollow double-diamond frameworks shifted 0.25c along ⟨001⟩ and adhered to each other crystallographically due to the loss of the mutual support in the unique synthesis, forming a tetragonal structure (space group I4 1 /amd). The unit cell parameter was changed from a = 168 to ∼240 nm with c = √2a by tuning the synthesis condition and the wide edge of the macropore size was ∼100 to ∼140 nm. Electron crystallography was applied to solve the structure. Our studies demonstrate electron crystallography is the only way to solve the complex structure in such length scale. Besides, this structure exhibits structural color that ranged from violet to blue from different directions with the bandgap in the visible wavelength range, which is attributed to the structural feature of the adhered frameworks that have lower symmetry. Calculations demonstrate that this is a new type of photonic structure. A complete gap can be obtained with a minimum dielectric contrast of 4.6, which is inferior to the single diamond but superior to the single gyroid structure. A multilayer core−shell bicontinuous microphase templating route was speculated for the formation of the unique macroporous structure, in which common solvent tetrahydrofuran in hydrophobic shell and selective solvent water in hydrophilic core to enlarge each microphase sizes.

Programmed cell death, or apoptosis, is a highly conserved cellular process that has been intensively investigated in nematodes, flies and mammals. The genetic conservation, the low redundancy, the feasibility for high-throughput genetic screens and the identification of temporally and spatially regulated apoptotic responses make Drosophila melanogaster a great model for the study of apoptosis. Here, we review the key players of the cell death pathway in Drosophila and discuss their roles in apoptotic and non-apoptotic processes.