Ultrastructure of the compound eye of the diploid female beetle,Xyleborus ferrugineus

Summary The compound eye of female (diploid) Xyleborus ferrugineus beetles was examined with scanning and transmission electron microscopy. The eye is emarginate, and externally consists of roughly 70–100 facets. Each ommatidium is composed of a thickly biconvex lenslet with about 50 electron dense and rare layers. The lens facet overlies a crystalline cone of the acone type which is roughly hourglass-shaped. Pigment cells envelop the entire ommatidium, and pigment granules also are abundant throughout the cytoplasm of the 8 retinular cells. The rhabdomeres of 2 centrally situated photoreceptor cells effectively fuse into a rhabdom that extends from the base of the crystalline cone deeply into the ommatidium. Six distal peripheral retinular cells encircle the 2 central cells, and their rhabdomeres join laterally to form a rhabdomeric ring around the central rhabdom. The rhabdom and rhabdomeric ring are effectively separated by the cytoplasm of the two central retinular cells which contains the usual organelles and an abundance of shielding pigment granules. Eight axons per ommatidium gather in a tracheae-less fascicle before exiting the eye through the fenestrate basement membrane. No tracheation was observed among the retinular cells. Each Semper cell of each observed crystalline cone contained an abundance of virus-like particles near the cell nucleus. The insect is laboratory reared, and the visual system seems very amenable to photoreceptor investigations.This research was supported by the Director of the Research Division, C.A.L.S., University of Wisconsin, Madison; and in part by research grant No. RR-00779 from the Division of Research Resources, National Institutes of Health and by funds from the Schoenleber Foundation, Milwaukee, WI to D.M.N.     

ZAKβ antagonizes and ameliorates the cardiac hypertrophic and apoptotic effects induced by ZAKα

ZAK (sterile alpha motif and leucine zipper containing kinase AZK), a serine/threonine kinase with multiple biochemical functions, has been associated with various cell processes, including cell proliferation, cell differentiation, and cardiac hypertrophy. In our previous reports, we found that the activation of ZAKα signaling was critical for cardiac hypertrophy. In this study, we show that the expression of ZAKα activated apoptosis through both a FAS‐dependent pathway and a mitochondria‐dependent pathway by subsequently inducing caspase‐3. ZAKβ, an isoform of ZAKα, is dramatically expressed during cardiac hypertrophy and apoptosis. The interaction between ZAKα and ZAKβ was demonstrated here using immunoprecipitation. The results show that ZAKβ has the ability to diminish the expression level of ZAKα. These findings reveal an inherent regulatory role of ZAKβ to antagonize ZAKα and to subsequently downregulate the cardiac hypertrophy and apoptosis induced by ZAKα.     

Variation in the transition from inside to outside work in the red harvester ant Pogonomyrmex barbatus

Summary. In laboratory colonies of the red harvester ant, Pogonomyrmex barbatus, we observed the sequence of tasks performed by marked individuals. Observations of about 760 ants in three laboratory colonies indicate that ants often move from inside to outside work. However, there was a great deal of variation in the sequence. If trends in sequence were weak because ants do move from inside to outside work but the duration of our observations was too short to see the transition, ants should be observed to stay either inside or outside. There was no significant tendency for ants to persist in inside or outside work, indicating the variability in sequence is real. Ants tended to perform midden work before they died. Foraging activity is low in laboratory colonies, and it may be that ants that would be foragers in the field end up as midden workers in the laboratory. High variability in task sequence, in uniform laboratory conditions, contrasts with the apparently more consistent sequence from inside to outside work in the field. This suggests that requirements imposed by variable external conditions and colony needs in the field have a strong influence on task sequence.Received 7 May 2004; revised 11 November 2004; accepted 18 November 2004.     

Global phylogeny of Hadrosauridae (Dinosauria: Ornithopoda) using parsimony and Bayesian methods

The late Cretaceous hadrosaurids were the most specialized and diverse clade of ornithopod dinosaurs. Parsimony and Bayesian methods were implemented to elucidate the phylogenetic relationships of all hadrosaurid species. Traditional and geometric morphometrics were applied to discover patterns of variation containing phylogenetic information. In total, 286 phylogenetically informative characters (196 cranial and 90 postcranial) were defined and documented: the most extensive character data set ever constructed for hadrosaurid dinosaurs. Of these, 136 characters were used for the first time in phylogenetic analysis of these ornithopods, and 93 were modified from those of other authors. Parsimony and the Bayesian analysis (using the Mk model without the gamma parameter) confirmed the split of hadrosaurids into Saurolophinae and Lambeosaurinae. Saurolophines included a major clade composed of the Prosaurolophus–Saurolophus and the Kritosaurus–Gryposaurus–Secernosaurus subclades. Edmontosaurus and Shantungosaurus were recovered outside the major clade of saurolophines. The Brachylophosaurus clade was recovered as the most basal clade of saurolophines in the parsimony analysis, whereas following the Bayesian analysis it was recovered as the sister clade to the Kritosaurus–Gryposaurus–Secernosaurus clade. These two analyses resulted in a Lambeosaurinae composed of a succession of Eurasian sister taxa to two major clades: the Parasaurolophus clade and the Hypacrosaurs altispinus–Corythosaurus clade. In contrast, the Bayesian analysis using the Mk model with the gamma parameter included, resulted in an unbalanced hadrosauroid tree, with a paraphyletic Saurolophinae, and with the Prosaurolophus clade, Edmontosaurus, and Shantungosaurus as successively closer sister taxa to Lambeosaurinae. Based on the strict reduced consensus tree derived from the parsimony analysis, Hadrosauridae was redefined as the clade stemming from the most recent common ancestor of Hadrosaurus foulkii and Parasaurolophus walkeri. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 159 , 435–502.     

Mutation glass-like of Drosophila melanogaster Suppresses Expression of mini-white Transgenes Depending on Their Genomic Environment

Pleiotropic recessive mutation glass-like (gl-l) found in region 8C10–8E of the X chromosome was shown to cause glass-like eyes having no boundaries between facets and a nonuniform pigment distribution determined by the endogenous white. The gl-lmutation completely inhibited expression of the mini-white transgene contained in several constructs, but the effect depended on the site of construct insertion in the genome. The mutation had no effect on the expression of the white transgene having the enhancer and flanked by insulators. The gl-l mutation did not affect the extent of mosaic eye pigmentation when a construct with mini-white was inserted in the telomeric or pericentric region. However, in most cases it completely inhibited the mosaic mini-white expression when cloned heterochromatic repeats were adjacent to the reporter gene in a construct. The gl-l gene was assumed to play a role in the formation of the chromatin structure, because the effect of its mutation on expression of the white transgene depended on the transgene insertion site, the presence of insulators or an enhancer in the vicinity of the transgene, and on the adjacent heterochromatic repeats.