Snout Shape in Extant Ruminants

Copyright: © 2014 Tennant, MacLeod. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. [4.0 license]. The attached file is the published version of the article

Duox, Flotillin-2, and Src42A Are Required to Activate or Delimit the Spread of the Transcriptional Response to Epidermal Wounds in Drosophila

The epidermis is the largest organ of the body for most animals, and the first line of defense against invading pathogens. A breach in the epidermal cell layer triggers a variety of localized responses that in favorable circumstances result in the repair of the wound. Many cellular and genetic responses must be limited to epidermal cells that are close to wounds, but how this is regulated is still poorly understood. The order and hierarchy of epidermal wound signaling factors are also still obscure. The Drosophila embryonic epidermis provides an excellent system to study genes that regulate wound healing processes. We have developed a variety of fluorescent reporters that provide a visible readout of wound-dependent transcriptional activation near epidermal wound sites. A large screen for mutants that alter the activity of these wound reporters has identified seven new genes required to activate or delimit wound-induced transcriptional responses to a narrow zone of cells surrounding wound sites. Among the genes required to delimit the spread of wound responses are Drosophila Flotillin-2 and Src42A, both of which are transcriptionally activated around wound sites. Flotillin-2 and constitutively active Src42A are also sufficient, when overexpressed at high levels, to inhibit wound-induced transcription in epidermal cells. One gene required to activate epidermal wound reporters encodes Dual oxidase, an enzyme that produces hydrogen peroxide. We also find that four biochemical treatments (a serine protease, a Src kinase inhibitor, methyl-ß-cyclodextrin, and hydrogen peroxide) are sufficient to globally activate epidermal wound response genes in Drosophila embryos. We explore the epistatic relationships among the factors that induce or delimit the spread of epidermal wound signals. Our results define new genetic functions that interact to instruct only a limited number of cells around puncture wounds to mount a transcriptional response, mediating local repair and regeneration

Changes in resource concentration and defence during leaf development in a tough-leaved (Nothofagus moorei) and soft-leaved (Toona ciliata) species

Developing leaves that are soft, with high concentrations of resources, can be particularly vulnerable to herbivore damage. Since a developing leaf cannot be very tough, given the constraints of cell expansion, the major form of protection is likely to be chemical defence. We investigated changes in concentration of herbivore resources (protein, carbohydrates and water) and putative defences (total phenolics, tannin activity, cyanogenic glycosides, alkaloids, cell wall, and leaf mechanics) across five leaf development stages of the soft-leaved Toona ciliata M. Roem. and the tough-leaved Nothofagus moorei (F. Muell.) Krasser. Chemical defences were predicted to be more highly developed in young than expanded leaves of both species, and to decline more in expanded leaves of N. moorei, which become tough and strong at maturity, than in the softer expanded leaves of T. ciliata. Resources and defences were dynamic within the developing leaves. Highest concentrations of protein were recorded in young leaves in both species, and highest levels of non-structural carbohydrate were recorded in young leaves of T. ciliata. Allocation to defence varied in both amount and type across leaf stages. In T. ciliata, there was an increase in chemical defence in expanded leaves (tannin activity, alkaloids). However, in N. moorei, increasing strength and toughness of developing leaves coincided with decreasing chemical defence, consistent with our hypothesis. For phenolics, this decrease was partly due to dilution by cell wall, but cyanogenic glycosides were present in young leaves and absent in fully mature leaves. These results are consistent with leaf toughness acting as an effective anti-herbivore defence, thereby reducing the need for investment in chemical defence

Wood properties and trunk allometry of co-occurring rainforest canopy trees in a cyclone-prone environment.

ACL-11-64International audience* Premise of study: New Caledonia commonly experiences cyclones, so trees there are expected to have enhanced wood traits and trunk allometry that confer resistance to wind damage. We ask whether there is evidence of a trade-off between these traits and growth rate among species. * Methods: Wood traits, including density, microfibril angle (MFA), and modulus of elasticity (MOE), ratio of tree height to stem diameter, and growth rate were investigated in mature trees of 15 co-occurring canopy species in a New Caledonian rainforest. * Key results: In contrast to some studies, wood density did not correlate negatively with growth increment. Among angiosperms, wood density and MOE correlated positively with diameter-adjusted tree height, and MOE correlated positively with stem-diameter growth increment. Tall slender trees achieved high stiffness with high efficiency with respect to wood density, in part by low MFA, and with a higher diameter growth increment but a lower buckling safety factor. However, some tree species of a similar niche differed in whole-tree resistance to wind damage and achieved wood stiffness in different ways. * Conclusions: There was no evidence of a growth-safety trade-off in these trees. In forests that regularly experience cyclones, there may be stronger selection for high wood density and/or stiffness in fast-growing trees of the upper canopy, with the potential growth trade-off amortized by access to the upper canopy and by other plant traits. Furthermore, decreasing wood density does not necessarily decrease resistance to wind damage, resistance being influenced by other characteristics including cell-level traits (e.g., MFA) and whole-plant architecture

Post-User-Selection Quantization and Estimation of Correlated Frobenius and Spectral Channel Norms

This paper considers quantization and exact minimum mean square error (MMSE) estimation of the squared Frobenius norm and the squared spectral norm of a Rayleigh fading multiple-input multiple-output (MIMO) channel with one-sided spatial correlation. The Frobenius and spectral norms are of great importance when describing the achievable capacity of many wireless communication systems; in particularly, they correspond to the signal-to-noise ratio (SNR) of space-time block coded and maximum ratio combining transmissions, respectively. Herein, a general quantization framework is presented, where the quantization levels are determined to maximize the feedback entropy. Quantization based on the post-user-selection distribution is discussed, and analyzed for a specific scheduler. Finally, exact results on MMSE estimation of the capacity and the SNR, conditioned on a quantized channel norm, are presented.© 2008 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. QC 20110411</p