IKK phosphorylates Huntingtin and targets it for degradation by the proteasome and lysosome

Expansion of the polyglutamine repeat within the protein Huntingtin (Htt) causes Huntington's disease, a neurodegenerative disease associated with aging and the accumulation of mutant Htt in diseased neurons. Understanding the mechanisms that influence Htt cellular degradation may target treatments designed to activate mutant Htt clearance pathways. We find that Htt is phosphorylated by the inflammatory kinase IKK, enhancing its normal clearance by the proteasome and lysosome. Phosphorylation of Htt regulates additional post-translational modifications, including Htt ubiquitination, SUMOylation, and acetylation, and increases Htt nuclear localization, cleavage, and clearance mediated by lysosomal-associated membrane protein 2A and Hsc70. We propose that IKK activates mutant Htt clearance until an age-related loss of proteasome/lysosome function promotes accumulation of toxic post-translationally modified mutant Htt. Thus, IKK activation may modulate mutant Htt neurotoxicity depending on the cell's ability to degrade the modified species

Rates of species introduction to a remote oceanic island

The introduction of species to areas beyond the limits of their natural distributions has a major homogenizing influence, making previously distinct biotas more similar. The scale of introductions has frequently been commented on, but their rate and spatial pervasiveness have been less well quantified. Here, we report the findings of a detailed study of pterygote insect introductions to Gough Island, one of the most remote and supposedly pristine temperate oceanic islands, and estimate the rate at which introduced species have successfully established. Out of 99 species recorded from Gough Island, 71 are established introductions, the highest proportion documented for any Southern Ocean island. Estimating a total of approximately 233 landings on Gough Island since first human landfall, this equates to one successful establishment for every three to four landings. Generalizations drawn from other areas suggest that this may be only one-tenth of the number of pterygote species that have arrived at the island, implying that most landings may lead to the arrival of at least one alien. These rates of introduction of new species are estimated to be two to three orders of magnitude greater than background levels for Gough Island, an increase comparable to that estimated for global species extinctions (many of which occur on islands) as a consequence of human activities

Diversität in der F5 von dynamisch evolvierenden Weizen Composite Cross Populationen

Three winter wheat composite cross (CC) populations were created in 2001 in the UK consisting either of 20 modern wheat parents (called A Population), a subset of 12 high quality parents (Q), or a subset of 9 high yielding parents (Y). Seed of the F4 was transferred to the University of Kassel in 2005 and the populations were grown since then under organic and conventional conditions in well separated large (>100m2) plots in two parallel sets (12 populations total) without conscious selection applied. In the conventional system fungicides and insecticides were not applied to expose the populations to natural pest and disease pressure. Morphological diversity, diseases, and yield were assessed in the field every season. The parents and a total of 1379 single plants of 23 single seed progenies of the F5 were tested in the laboratory for their combined resistance to three brown rust isolates. Only one progeny was homogenous in reaction, all others were mixtures of two to eight three-locus genotypes. Despite the supposed inbreeding structure of wheat one association in the Q progenies was random suggesting recent out-crossing. Thus, diversity and heterogeneity was still high in the F6 with evidence that out-crossing still played a role and contributed to this heterogeneity

Reactions of the excited state of polypyridyl chromium(III) ions

The quenching of the [superscript]2E state of CrL[subscript]3[superscript]3+ (where L = 2,2[superscript]\u27-bipyridine, 1,10-phenanthroline and their substituted analogues) by oxalate ions and by the organochromium complexes L[superscript]\u27CrR[superscript]2+ (where L[superscript]\u27 = (15) aneN[subscript]4 and R = primary alkyl, secondary alkyl, arylalkyl) was studied. Also investigated was the reactions of the organochromiums with Ru(bpy)[subscript]3[superscript]3+. Both formation of CrL[subscript]3[superscript]2+ and the loss of [superscript]\*CrL[subscript]3[superscript]3+ can be monitored conveniently enabling the determination of the kinetics as well as the products of the reaction;The reaction of oxalate ions at neutral pH with the excited chromium polypyridyl complexes is an electron transfer process as shown by the trend in rate constants with the one electron reduction potentials of the various [superscript]\*CrL[subscript]3[superscript]3+ species. The quenching reaction apparently proceeds via an ion-pairing pathway. A reactive species is produced in the quench which either produces another equivalent of electron transfer products or a secondary transient depending on the identity of the chromium polypyridyl complex;Reaction of the [superscript]\*CrL[subscript]3[superscript]3+ with the organochromiums appears to be an electron transfer process based on the reactivity pattern in varying the chromium polypyridyl (and consequently the potential) as well as the trend in varying the organic moiety of the L[superscript]\u27CrR[superscript]2+. This last reactivity pattern is that observed in the reactions of the organochromiums and the good outer sphere electron transfer agent, Ru(bpy)[subscript]3[superscript]3+. One electron oxidation of L[superscript]\u27CrR[superscript]2+ produces an unstable species which may undergo a one electron reduction (back electron transfer) or homolyze producing organic radicals

RESILIENCE IN ADOLESCENT AMERICAN STUDENTS

The current study sought to determine if any meaningful relationship existed between perceived mental, emotional/behavioral, and academic resilience and overall resilience in adolescent American students. The current quantitative study was conducting using convenience sampling though a national school counselors’ website. Respondents were asked to respond to a modified version of the ARS-30 resiliency questionnaire as well as respond to a few demographic questions. The findings of the study demonstrated that each aspect of adolescent student resilience (mental, emotional/behavioral, and academic) were statistically significant predictors of overall student resilience; with academic resilience being the most statistically significant predictor of perceived overall resilience in adolescent American students. The findings of the current study give a starting point in measuring American adolescent resilience in the wake of the COVID-19 pandemic. Additionally, the findings of the current study support previous research about the positive outcomes of resilience in students in academic settings

Locomotion of circular robots with diametrically translating legs: Design, analysis, and fabrication

This work develops an analytical basis for designing the locomotion of mobile robots with a circular core and equispaced diametral legs which actuate linearly. Two elementary regimes of motion are first developed using the intrinsic geometry of the mechanism, then combined for fluid motion. The first and primary gait has a path trajectory defined by its kinematic constraints. Dynamics are explored to assist actuator design and understand the mechanism\u27s constraint forces. Simulation results are provided in support of the design concept and geometric optimization. The proposed robot, or Locomotive Amoebic Device (LAD), bears resemblance with certain cellular locomotion, and thus miniaturization is a possibility. A prototype of LAD is constructed which supports the design theory and simulation by executing the primary motion regime with appropriate speed and current settings. Future work is promising for extending the design to a spherical concept, generalizing the theory in terms of the number of legs, creating a variety of control schemes for maneuvers such as dampening phase transitions or pure rolling, equipping and justifying the design for applications such as Planetary Exploration or Medical Procedures, and potentially creating a millimeter scale version or smaller of spherical LAD. This thesis theorizes a unique mode of locomotion and proffers simulation and experimental support

Quantum Effects in Neural Networks

We develop the statistical mechanics of the Hopfield model in a transverse field to investigate how quantum fluctuations affect the macroscopic behavior of neural networks. When the number of embedded patterns is finite, the Trotter decomposition reduces the problem to that of a random Ising model. It turns out that the effects of quantum fluctuations on macroscopic variables play the same roles as those of thermal fluctuations. For an extensive number of embedded patterns, we apply the replica method to the Trotter-decomposed system. The result is summarized as a ground-state phase diagram drawn in terms of the number of patterns per site, $\alpha$, and the strength of the transverse field, $\Delta$. The phase diagram coincides very accurately with that of the conventional classical Hopfield model if we replace the temperature T in the latter model by $\Delta$. Quantum fluctuations are thus concluded to be quite similar to thermal fluctuations in determination of the macroscopic behavior of the present model.Comment: 34 pages, LaTeX, 9 PS figures, uses jpsj.st

Effects of patch size and density on flower visitation and seed set of wild plants: a pan-European approach

1. Habitat fragmentation can affect pollinator and plant population structure in terms of species composition, abundance, area covered and density of flowering plants. This, in turn, may affect pollinator visitation frequency, pollen deposition, seed set and plant fitness. 2. A reduction in the quantity of flower visits can be coupled with a reduction in the quality of pollination service and hence the plants’ overall reproductive success and long-term survival. Understanding the relationship between plant population size and⁄ or isolation and pollination limitation is of fundamental importance for plant conservation. 3. Weexamined flower visitation and seed set of 10 different plant species fromfive European countries to investigate the general effects of plant populations size and density, both within (patch level) and between populations (population level), on seed set and pollination limitation. 4. Wefound evidence that the effects of area and density of flowering plant assemblages were generally more pronounced at the patch level than at the population level. We also found that patch and population level together influenced flower visitation and seed set, and the latter increased with increasing patch area and density, but this effect was only apparent in small populations. 5. Synthesis. By using an extensive pan-European data set on flower visitation and seed set we have identified a general pattern in the interplay between the attractiveness of flowering plant patches for pollinators and density dependence of flower visitation, and also a strong plant species-specific response to habitat fragmentation effects. This can guide efforts to conserve plant–pollinator interactions, ecosystem functioning and plant fitness in fragmented habitats