A Limited Role for Suppression in the Central Field of Individuals with Strabismic Amblyopia.

yesBackground: Although their eyes are pointing in different directions, people with long-standing strabismic amblyopia typically do not experience double-vision or indeed any visual symptoms arising from their condition. It is generally believed that the phenomenon of suppression plays a major role in dealing with the consequences of amblyopia and strabismus, by preventing images from the weaker/deviating eye from reaching conscious awareness. Suppression is thus a highly sophisticated coping mechanism. Although suppression has been studied for over 100 years the literature is equivocal in relation to the extent of the retina that is suppressed, though the method used to investigate suppression is crucial to the outcome. There is growing evidence that some measurement methods lead to artefactual claims that suppression exists when it does not. Methodology/Results: Here we present the results of an experiment conducted with a new method to examine the prevalence, depth and extent of suppression in ten individuals with strabismic amblyopia. Seven subjects (70%) showed no evidence whatsoever for suppression and in the three individuals who did (30%), the depth and extent of suppression was small. Conclusions: Suppression may play a much smaller role in dealing with the negative consequences of strabismic amblyopia than previously thought. Whereas recent claims of this nature have been made only in those with micro-strabismus our results show extremely limited evidence for suppression across the central visual field in strabismic amblyopes more generally. Instead of suppressing the image from the weaker/deviating eye, we suggest the visual system of individuals with strabismic amblyopia may act to maximise the possibilities for binocular co-operation. This is consistent with recent evidence from strabismic and amblyopic individuals that their binocular mechanisms are intact, and that, just as in visual normals, performance with two eyes is better than with the better eye alone in these individuals

Long-Term Survival of Hydrated Resting Eggs from Brachionus plicatilis

Several organisms display dormancy and developmental arrest at embryonic stages. Long-term survival in the dormant form is usually associated with desiccation, orthodox plant seeds and Artemia cysts being well documented examples. Several aquatic invertebrates display dormancy during embryonic development and survive for tens or even hundreds of years in a hydrated form, raising the question of whether survival in the non-desiccated form of embryonic development depends on pathways similar to those occurring in desiccation tolerant forms

Enhancing abiotic stress tolerance in plants by modulating properties of stress responsive transcription factors

Drought, heat and other abiotic stresses negatively impact growth, development, yield and seed quality of plants. The perception of stress and later adaptation to it occurs via signal transduction pathways that regulate expression of stress-responsive genes. Products of these genes include proteins that are directly involved in plant protection and those that fulfill regulatory function. The latter group includes transcription factors (TFs) and other transcription-related proteins that are investigated using the tools of forward and reverse genetics. Genomics analyses also revealed the importance of other proteins such as protein kinases and phosphatases, enzymes involved in metabolism of phospholipids, signalling molecules, etc. Once the stress response pathways are described, the role of key players in these pathways can be optimised through allele mining, selection and genetic engineering. These approaches offer alternatives to classical breeding and marker-assisted selection. During plant responses to drought, a set of basic leucine zipper (bZIP), homeodomain-leucine zipper (HD-Zip) and WRKY TFs are transcriptionally or post-translationally activated via abscisic acid (ABA)-dependent signal transduction pathways. Despite a surge of data on the significance of plant bZIP, HD-Zip and WRKY TFs in the regulation of drought responses, the three-dimensional (3D) structures of these classes of TFs have been poorly defined. This structural information can be used for rational design of variant TFs that can help in understanding their oligomerisation and post-translational modification patterns, as well as their abilities to recognise target DNA sequences. In turn, this knowledge would permit the commercial application of genetically engineered TFs in agricultural biotechnology, by expression of TF variants and using the wild-type or modified promoter regions of stress-responsive genes. To this end, the aim of this review is to discuss strategies for improving tolerance of cereals to drought and other environmental stresses using molecular variants of the abiotic stress responsive TFs.Maria Hrmova and Sergiy Lopat