A Hox gene mutation that triggers Nonsense-mediated RNA decay and affects alternative splicing during Drosophila development

Nonsense mutations are usually assumed to affect protein function by generating truncated protein products. Nonetheless, it is now clear that these mutations affect not just protein synthesis but also messenger RNA stability. The surveillance mechanism responsible for the detection and degradation of 'nonsense' RNA messages is termed nonsense-mediated RNA decay (NMD). Essential biochemical components of the NMD machinery have been defined in several species. Here we identify the Drosophila orthologue of one of these factors, Upf1, and document its expression during embryogenesis. To test whether NMD acts during Drosophila development, we make use of a mutation that introduces a stop codon into a variably spliced exon of the Hox gene Ultrabithorax (Ubx). Using real-time quantitative RT-PCR we demonstrate that Ubx transcripts containing the premature stop codon are expressed at lower levels than their wild type counterpart. Unexpectedly, we also find that the same mutation significantly increases the levels of a Ubx splicing isoform that lacks the exon containing the premature termination codon. These findings indicate that NMD is operational during Drosophila development and suggest that nonsense mutations may affect development by altering the spectrum of splicing products formed, as well as by reducing or eliminating protein synthesis

Odd-paired controls frequency doubling in Drosophila segmentation by altering the pair-rule gene regulatory network

The Drosophila embryo transiently exhibits a double-segment periodicity, defined by the expression of seven 'pair-rule' genes, each in a pattern of seven stripes. At gastrulation, interactions between the pair-rule genes lead to frequency doubling and the patterning of 14 parasegment boundaries. In contrast to earlier stages of Drosophila anteroposterior patterning, this transition is not well understood. By carefully analysing the spatiotemporal dynamics of pair-rule gene expression, we demonstrate that frequency-doubling is precipitated by multiple coordinated changes to the network of regulatory interactions between the pair-rule genes. We identify the broadly expressed but temporally patterned transcription factor, Odd-paired (Opa/Zic), as the cause of these changes, and show that the patterning of the even-numbered parasegment boundaries relies on Opa-dependent regulatory interactions. Our findings indicate that the pair-rule gene regulatory network has a temporally modulated topology, permitting the pair-rule genes to play stage-specific patterning roles.This work was supported by a BBSRC PhD studentship to Erik Clark

Inference of Temporally Varying Bayesian Networks

When analysing gene expression time series data an often overlooked but crucial aspect of the model is that the regulatory network structure may change over time. Whilst some approaches have addressed this problem previously in the literature, many are not well suited to the sequential nature of the data. Here we present a method that allows us to infer regulatory network structures that may vary between time points, utilising a set of hidden states that describe the network structure at a given time point. To model the distribution of the hidden states we have applied the Hierarchical Dirichlet Process Hideen Markov Model, a nonparametric extension of the traditional Hidden Markov Model, that does not require us to fix the number of hidden states in advance. We apply our method to exisiting microarray expression data as well as demonstrating is efficacy on simulated test data

Overcoming the shadow and achieving individuation through a Hero's journey in Tunku Halim's "A Sister's Tale"

In Jungian psychology, Individuation is the process of achieving psychological maturation wherein individuals are able to integrate their conscious and unconscious mind to create a balanced psyche. One aspect of the unconscious mind that needs to be integrated with the conscious is the Shadow, a psychological component consisting of all rejected and repressed aspects of one's personality. The process of dealing with the Shadow aspect is analogous to the journey of the Hero archetype, and the goal of this journey is Individuation, whereby one becomes connected to their Self, an archetype that represents wholeness and totality. In Tunku Halim's "A Sister's Tale" (1999), Jessica has been pulled into a Hero's journey because of an unaddressed repressed guilt that ultimately becomes her Shadow. This paper aims to examine Jessica's Heroic journey in attaining her Self through the integration of her unconscious component, the Shadow, with her consciousness. To achieve this objective, the text is analysed through Jungian's concept of the Shadow and Hero archetypes. The findings reveal that Jessica's Shadow had become too dense for a successful integration to occur and therefore, she failed to achieve Individuation

XX/XY System of Sex Determination in the Geophilomorph Centipede Strigamia maritima.

We show that the geophilomorph centipede Strigamia maritima possesses an XX/XY system of sex chromosomes, with males being the heterogametic sex. This is, to our knowledge, the first report of sex chromosomes in any geophilomorph centipede. Using the recently assembled Strigamia genome sequence, we identified a set of scaffolds differentially represented in male and female DNA sequence. Using quantitative real-time PCR, we confirmed that three candidate X chromosome-derived scaffolds are present at approximately twice the copy number in females as in males. Furthermore, we confirmed that six candidate Y chromosome-derived scaffolds contain male-specific sequences. Finally, using this molecular information, we designed an X chromosome-specific DNA probe and performed fluorescent in situ hybridization against mitotic and meiotic chromosome spreads to identify the Strigamia XY sex-chromosome pair cytologically. We found that the X and Y chromosomes are recognizably different in size during the early pachytene stage of meiosis, and exhibit incomplete and delayed pairing.This work was in part funded by Wellcome Trust (wellcome.ac.uk) Ph.D. studentship WT089615MA to JEG. Cytological experiments by MD and FM were funded by Grant IAA600960925 of the Grant Agency of The Czech Academy of Sciences (until 2013; gaav.cz) and by Grant 14- 22765S of the Czech Science Foundation (since 2014; gacr.cz). KS was supported by JSPS Excellent Young Researchers Overseas Visit Program (21– 7147; jsps.go.jp).This is the final version of the article. It first appeared from the Public Library of Science (PLOS) via https://doi.org/10.1371/journal.pone.015029

Does visual flicker phase at gamma frequency modulate neural signal propagation and stimulus selection?

Oscillatory synchronization of neuronal populations has been proposed to play a role in perceptual integration and attentional processing. However, some conflicting evidence has been found with respect to its causal relevance for sensory processing, particularly when using flickering visual stimuli with the aim of driving oscillations. We tested psychophysically whether the relative phase of gamma frequency flicker (60 Hz) between stimuli modulates well-known facilitatory lateral interactions between collinear Gabor patches (Experiment 1) or crowding of a peripheral target by irrelevant distractors (Experiment 2). Experiment 1 assessed the impact of suprathreshold Gabor flankers on detection of a near-threshold central Gabor target (“Lateral interactions paradigm”). The flanking stimuli could flicker either in phase or in anti-phase with each other. The typical facilitation of target detection was found with collinear flankers, but this was unaffected by flicker phase. Experiment 2 employed a “crowding” paradigm, where orientation discrimination of a peripheral target Gabor patch is disrupted when surrounded by irrelevant distractors. We found the usual crowding effect, which declined with spatial separation, but this was unaffected by relative flicker phase between target and distractors at all separations. These results imply that externally driven manipulations of gamma frequency phase cannot modulate perceptual integration in vision

Simulation of heat transfer efficiency for novel air cooling channels of a fuel cell bipolar plate / Wimi Akam

This study focused on designing and simulating a suitable air cooling for fuel cell bipolar plate with power rating of 3kW. For 3kW application, normally the fuel cells uses water as a medium to remove the heat generated. Instead of using water, air is to be used as a cooling medium. Simulation works are conducted to determine which design will gives the better result of heat transfer rate using air cooling. Two of the alternative design are zigzaged and inclined 2 degree channels. The lower the temperature at outlet will result in higher heat tansfer effeciency of the fuel cells. To obtain the result, two dimension steady state computational fluid dynamic analysis using two equation turbulence model ( k-c model). The work uses Star Design; an CFD software to estimate the temperature distribution at the surface of the bipolar plate. The result shows that design 2 which is having slightly inclined of 2 degree gives the most highest heat transfer rate

Stories in Motion: Integrating Creative Dance in a Language Arts Classroom

As learning gaps have widened in the wake of the COVID-19 pandemic, there has been an increased need for research-based strategies to improve student academic achievement and engagement. This study explored the integration of creative dance as a form of storytelling in a kindergarten language arts classroom. Students were introduced to an element of dance and used it to create short dance phrases in a unit on retelling. Both qualitative and quantitative data was collected using pre/post tests and student interviews measuring students’ engagement and enjoyment. Students involved in this study showed significant growth in their ability to orally retell a story (p \u3c .05) and analysis of student interviews suggested that students were highly engaged in the unit

The European Court of Human Rights: achievements and challenges

Respect for human rights and fundamental freedom is anchored on the sanctity of life and dignity of man. It is an expression of equality of men. It is the core principle of the constitution of every democratic society. Today, the principles have been documented with solemn declaration and undertaking to respect and observe same at national, regional and world over. This work is limited to the European Court of Human Rights, its successes and failures and a call for reform to enhance its productivity in the attainment of the core objectives for which it was established in 1953.The research employs critical content analysis of relevant legislation. It found that the regional court system has enhanced respect for human rights in the region and calls for stiffer sanction for disobedience to the decision of the court.Keywords: European, court, human, human right