Geotropism and the lateral transport of auxin in the corn mutant amylomaize

Summary In coleoptiles of the amylomaize corn mutant (AM), the amyloplasts are much reduced in size in comparison with the wild type corn (WT), permitting a comparison of geotropic responsiveness as related to lateral displacement of amyloplasts and lateral transport of auxin. The amyloplasts of AM showed 30–40% lesser lateral redistribution in response to horizontal exposure in comparison with WT. With geotropic stimulation, the lateral transport of auxin in the direction of growth was 40–80% less, and the geotropic curvature by the coleoptiles was also significantly less in the mutant as compared with WT. These correlations support the hypothesis that the starch plastids serve as gravity sensors in the geotropic responses of coleoptiles.     

Gene expression patterns in anterior pituitary associated with quantitative measure of oestrous behaviour in dairy cows

Intensive selection for high milk yield in dairy cows has raised production levels substantially but at the cost of reduced fertility, which manifests in different ways including reduced expression of oestrous behaviour. The genomic regulation of oestrous behaviour in bovines remains largely unknown. Here, we aimed to identify and study those genes that were associated with oestrous behaviour among genes expressed in the bovine anterior pituitary either at the start of oestrous cycle or at the mid-cycle (around day 12 of cycle), or regardless of the phase of cycle. Oestrous behaviour was recorded in each of 28 primiparous cows from 30 days in milk onwards till the day of their sacrifice (between 77 and 139 days in milk) and quantified as heat scores. An average heat score value was calculated for each cow from heat scores observed during consecutive oestrous cycles excluding the cycle on the day of sacrifice. A microarray experiment was designed to measure gene expression in the anterior pituitary of these cows, 14 of which were sacrificed at the start of oestrous cycle (day 0) and 14 around day 12 of cycle (day 12). Gene expression was modelled as a function of the orthogonally transformed average heat score values using a Bayesian hierarchical mixed model on data from day 0 cows alone (analysis 1), day 12 cows alone (analysis 2) and the combined data from day 0 and day 12 cows (analysis 3). Genes whose expression patterns showed significant linear or non-linear relationships with average heat scores were identified in all three analyses (177, 142 and 118 genes, respectively). Gene ontology terms enriched among genes identified in analysis 1 revealed processes associated with expression of oestrous behaviour whereas the terms enriched among genes identified in analysis 2 and 3 were general processes which may facilitate proper expression of oestrous behaviour at the subsequent oestrus. Studying these genes will help to improve our understanding of the genomic regulation of oestrous behaviour, ultimately leading to better management strategies and tools to improve or monitor reproductive performance in bovines.     

Range maps and species richness patterns: errors of commission and estimates of uncertainty

Range maps are often combined into “range overlap maps” to estimate spatial variation in species richness. Range maps are, in most cases, designed to represent a species’ maximum geographical extent and not patterns of occupancy within the range. As a consequence, range maps overestimate occupancy by presenting false occupancy (errors of commission) within the interior of the range. To assess the implications of errors of commission when developing and applying range overlap maps, we used neutral landscapes to simulate range maps and patterns of occupancy within ranges. We explored several scenarios based on combinations of six parameters defining biogeographical and cartographic factors typically encountered by investigators. Our results suggest that, in general, uncertainty is lowest when map resolutions are moderately fine, the majority of species have geographically restricted ranges, species occur throughout their range, patterns of occupancy within the range are not correlated among species, and geographically local and widespread species tend to occupy different regions. Several of these outcomes are associated with broad geographical extents, the scale at which range overlap maps are typically applied. Thus, under most circumstances, reasonably accurate and precise representation of species richness patterns can be achieved. However, these representations can be improved by enhancing occupancy data for widespread species – a primary source of uncertainty – and selecting a map resolution that captures relevant biological and environmental heterogeneity. Hence, by determining where a study is situated within the scenarios examined in our simulations, uncertainty and its sources and implications can be ascertained. With this knowledge, research goals, methods, and data sources can be reassessed and refined and, in the end, conclusions and recommendations can be qualified. Alternatively, unique regional, taxonomic, or cartographic factors could be included in future simulations to provide direct assessments of uncertainty.     

An urbilaterian origin of the tripartite brain: developmental genetic insights from Drosophila

Studies on expression and function of key developmental control genes suggest that the embryonic vertebrate brain has a tripartite ground plan that consists of a forebrain/midbrain, a hindbrain and an intervening midbrain/hindbrain boundary region, which are characterized by the specific expression of the Otx, Hox and Pax2/5/8 genes, respectively. We show that the embryonic brain of the fruitfly Drosophila melanogaster expresses all three sets of homologous genes in a similar tripartite pattern. Thus, a Pax2/5/8 expression domain is located at the interface of brain-specific otd/Otx2 and unpg/Gbx2 expression domains anterior to Hox expression regions. We identify this territory as the deutocerebral/tritocerebral boundary region in the embryonic Drosophila brain. Mutational inactivation of otd/Otx2 and unpg/Gbx2 result in the loss or misplacement of the brain-specific expression domains of Pax2/5/8 and Hox genes. In addition, otd/Otx2 and unpg/Gbx2 appear to negatively regulate each other at the interface of their brain-specific expression domains. Our studies demonstrate that the deutocerebral/tritocerebral boundary region in the embryonic Drosophila brain displays developmental genetic features similar to those observed for the midbrain/hindbrain boundary region in vertebrate brain development. This suggests that a tripartite organization of the embryonic brain was already established in the last common urbilaterian ancestor of protostomes and deuterostomes.     

Influence of lipids on membrane assembly and stability of the potassium channel KcsA

A novel antibacterial peptide, moricin, isolated from the silkworm Bombyx mori, consists of 42 amino acids. It is highly basic and the amino acid sequence has no significant similarity to those of other antibacterial peptides. The 20 structures of moricin in methanol have been determined from two-dimensional 1H-nuclear magnetic resonance spectroscopic data. The solution structure reveals an unique structure comprising of a long alpha-helix containing eight turns along nearly the full length of the peptide except for four N-terminal residues and six C-terminal residues. The electrostatic surface map shows that the N-terminal segment of the alpha-helix, residues 5-22, is an amphipathic alpha-helix with a clear separation of hydrophobic and hydrophilic faces, and that the C-terminal segment of the alpha-helix, residues 23-36, is a hydrophobic alpha-helix except for the negatively charged surface at the position of Asp30. The results suggest that the amphipathic N-terminal segment of the alpha-helix is mainly responsible for the increase in permeability of the membrane to kill the bacteria.     

Insulin-stimulated ribosomal protein synthesis in maize embryonic axes during germination

Addition of insulin to maize seed ( Zea mays L. cv. Chalqueño) was found to accelerate germination and seedling growth. Insulin-stimulated maize axes showed enhancement of 35 S-methionine incorporation into ribosomal proteins (rp) and mobilization of S₆ rp mRNA into polysomes. Increase in S₆ rp phosphorylation of the small ribosomal subunit (40S) was observed in 32 P-orthophosphate pulse-labeled experiments when maize axes were stimulated by insulin. Application of either wortmannin or rapamycin, inhibitors of protein kinases of the insulin transduction pathway, abolished the insulin stimulatory effect on S₆ rp phosphorylation and on ribosomal protein synthesis. The above data are interpreted as an indication of the existence of an insulin-stimulated signal transduction pathway in maize tissues that is involved in the regulation of translation.     

Association between APOC1 Polymorphism and Alzheimer’s Disease: A Case-Control Study and Meta-Analysis

Background

Previous association studies examining the relationship between the APOC1 polymorphism and susceptibility to Alzheimer’s disease (AD) have shown conflicting results, and it is not clear if an APOC1 variant acts as a genetic risk factor in AD etiology across multiple populations.

Methods

To confirm the risk association between APOC1 and AD, we designed a case-control study and also performed a meta-analysis of previously published studies.

Results

Seventy-nine patients with AD and one hundred fifty-six unrelated controls were included in case-control study. No association was found between the variation of APOC1 and AD in stage 1 of our study. However, our meta-analysis pooled a total of 2092 AD patients and 2685 controls. The APOC1 rs11568822 polymorphism was associated with increased AD risk in Caucasians, Asians and Caribbean Hispanics, but not in African Americans. APOE ε4 carriers harboring the APOC1 insertion allele, were more prevalent in AD patients than controls (χ² = 119.46, OR = 2.79, 95% CI = 2.31–3.36, P<0.01).

Conclusions

The APOC1 insertion allele, in combination with APOE ε4, likely serves as a potential risk factor for developing AD.     

Is EEG-biofeedback an Effective Treatment in Autism Spectrum Disorders? A Randomized Controlled Trial

EEG-biofeedback has been reported to reduce symptoms of autism spectrum disorders (ASD) in several studies. However, these studies did not control for nonspecific effects of EEG-biofeedback and did not distinguish between participants who succeeded in influencing their own EEG activity and participants who did not. To overcome these methodological shortcomings, this study evaluated the effects of EEG-biofeedback in ASD in a randomized pretest–posttest control group design with blinded active comparator and six months follow-up. Thirty-eight participants were randomly allocated to the EEG-biofeedback, skin conductance (SC)-biofeedback or waiting list group. EEG- and SC-biofeedback sessions were similar and participants were blinded to the type of feedback they received. Assessments pre-treatment, post-treatment, and after 6 months included parent ratings of symptoms of ASD, executive function tasks, and 19-channel EEG recordings. Fifty-four percent of the participants significantly reduced delta and/or theta power during EEG-biofeedback sessions and were identified as EEG-regulators. In these EEG-regulators, no statistically significant reductions of symptoms of ASD were observed, but they showed significant improvement in cognitive flexibility as compared to participants who managed to regulate SC. EEG-biofeedback seems to be an applicable tool to regulate EEG activity and has specific effects on cognitive flexibility, but it did not result in significant reductions in symptoms of ASD. An important finding was that no nonspecific effects of EEG-biofeedback were demonstrated.