The tertiary stratigraphy and echinoid palaeontology of Gozo, Malta

The following succession of Tertiaiy rocks is established on the Maltese island of Gozo (youngest "beds first): Upper Coralline Limestone, over 290 feet; Transitional Greensand, 0 to 40 feet J Blue Clay, 0 to 200 feet; Upper Globigerina Limestone, 40 to l10-feet; Middle Globigerina Limestone, 0 to 60 feet; Lower Globigerina Limestone, 17 to 75 feet; Scutella Bed, ½ to 20 feet; Lower Coralline Limestone, over 450 feet. The algal and foraminiferal Lower Coralline Limestone was probably deposited in shallow water. The prominent Scutella Bed resembles a near-surface shell bank. Two phosphatic nodule beds, possibly marking stagnant periods, separate the Globigerina Limestones. The lower and upper divisions are formed of pelagic foraminifera with lamellibranchs and neritic echinoids. The middle division, a marly limestone, may be a deep of water deposit but has an upper, coarser facies in south-west Gozo. The Lower and Middle Globigerina Limestones thin eastward and the latter is absent over much of the eastern area where the nodule beds coalesce. The Upper Globigerina Limestone— Blue Clay boundary, despite sane previous opinions, is always sharp. The two beds have faunal similarities, their lithological differences are probably caused by a sudden onset of mud deposition. Variations in, thickness of the Blue Clay are considered to have an erosional origin. There is a gradual passage through the glauconitic Transitional Greensand, which varies in thickness and lithology and has a thick-shelled fauna suggesting a shallow water origin, to the Upper Coralline Limestone, which has a soft, lower division and a hard upper one, complicated by lateral variation and later recementation. The echinoids from the above succession are listed and the following ten species are described and figured: Scutella subrotunda, Scutella sp. nov., Hemiaster scillae, Hemiaster cotteaui, Fericosmus latus, Gregoiyaster lorioli, Schizaster eurynotus, Schizaster parkinsoni, Eupatagus dekonincki, Echinolampas lucae

Genetically Encoded Whole Cell Biosensor for Drug Discovery of HIF-1 Interaction Inhibitors

The heterodimeric transcription factor, hypoxia inducible factor-1 (HIF-1), is an important anticancer target as it supports the adaptation and response of tumors to hypoxia. Here, we optimized the repressed transactivator yeast two-hybrid system to further develop it as part of a versatile yeast-based drug discovery platform and validated it using HIF-1. We demonstrate both fluorescence-based and auxotrophy-based selections that could detect HIF-1α/HIF-1β dimerization inhibition. The engineered genetic selection is tunable and able to differentiate between strong and weak interactions, shows a large dynamic range, and is stable over different growth phases. Furthermore, we engineered mechanisms to control for cellular activity and off-target drug effects. We thoroughly characterized all parts of the biosensor system and argue this tool will be generally applicable to a wide array of protein-protein interaction targets. We anticipate this biosensor will be useful as part of a drug discovery platform, particularly when screening DNA-encoded new modality drugs

ATRX, a member of the SNF2 family of helicase/ATPases, is required for chromosome alignment and meiotic spindle organization in metaphase II stage mouse oocytes

AbstractATRX is a centromeric heterochromatin binding protein belonging to the SNF2 family of helicase/ATPases with chromatin remodeling activity. Mutations in the human ATRX gene result in X-linked α-thalassaemia with mental retardation (ATRX) syndrome and correlate with changes in methylation of repetitive DNA sequences. We show here that ATRX also functions to regulate key stages of meiosis in mouse oocytes. At the germinal vesicle (GV) stage, ATRX was found associated with the perinucleolar heterochromatin rim in transcriptionally quiescent oocytes. Phosphorylation of ATRX during meiotic maturation is dependent upon calcium calmodulin kinase (CamKII) activity. Meiotic resumption also coincides with deacetylation of histone H4 at lysine 5 (H4K5 Ac) while ATRX and histone H3 methylated on lysine 9 (H3K9) remained bound to the centromeres and interstitial regions of condensing chromosomes, respectively. Inhibition of histone deacetylases (HDACs) with trichostatin A (TSA) disrupted ATRX binding to the centromeres of hyperacetylated chromosomes resulting in abnormal chromosome alignments at metaphase II (MII). Similarly, while selective ablation of ATRX by antibody microinjection and RNA interference (RNAi) had no effect on the progression of meiosis, it had severe consequences for the alignment of chromosomes on the metaphase II spindle. These results suggest that genome-wide epigenetic modifications such as global histone deacetylation are essential for the binding of ATRX to centromeric heterochromatin. Moreover, centromeric ATRX is required for correct chromosome alignment and organization of a bipolar meiotic metaphase II spindle

Towards an integrated experimental-theoretical approach for assessing the mechanistic basis of hair and feather morphogenesis

In his seminal 1952 paper, ‘The Chemical Basis of Morphogenesis’, Alan Turing lays down a milestone in the application of theoretical approaches to understand complex biological processes. His deceptively simple demonstration that a system of reacting and diffusing chemicals could, under certain conditions, generate spatial patterning out of homogeneity provided an elegant solution to the problem of how one of nature's most intricate events occurs: the emergence of structure and form in the developing embryo. The molecular revolution that has taken place during the six decades following this landmark publication has now placed this generation of theoreticians and biologists in an excellent position to rigorously test the theory and, encouragingly, a number of systems have emerged that appear to conform to some of Turing's fundamental ideas. In this paper, we describe the history and more recent integration between experiment and theory in one of the key models for understanding pattern formation: the emergence of feathers and hair in the skins of birds and mammals

Non-peptidic antagonists of the CGRP receptor, BIBN4096BS and MK-0974, interact with the calcitonin receptor-like receptor via methionine-42 and RAMP1 via tryptophan-74

The receptor for calcitonin gene-related peptide (CGRP) has been the target for the development of novel small molecule antagonists for the treatment of migraine. Two such antagonists, BIBN4096BS and MK-0974, have shown great promise in clinical trials and hence a deeper understanding of the mechanism of their interaction with the receptor is now required. The structure of the CGRP receptor is unusual since it is comprised of a hetero-oligomeric complex between the calcitonin receptor-like receptor (CRL) and an accessory protein (RAMP1). Both the CLR and RAMP1 components have extracellular domains which interact with each other and together form part of the peptide-binding site. It seems likely that the antagonist binding site will also be located on the extracellular domains and indeed Trp-74 of RAMP1 has been shown to form part of the binding site for BIBN4096BS. However, despite a chimeric study demonstrating the role of the N-terminal domain of CLR in antagonist binding, no specific residues have been identified. Here we carry out a mutagenic screen of the extreme N-terminal domain of CLR (residues 23-63) and identify a mutant, Met-42-Ala, which displays 48-fold lower affinity for BIBN4096BS and almost 900-fold lower affinity for MK-0974. In addition, we confirm that the Trp-74-Lys mutation at human RAMP1 reduces BIBN4096BS affinity by over 300-fold and show for the first time a similar effect for MK-0974 affinity. The data suggest that the non-peptide antagonists occupy a binding site close to the interface of the N-terminal domains of CLR and RAMP1

Electronic hand hygiene monitoring systems can be well-tolerated by health workers: Findings of a qualitative study

Background: Electronic hand hygiene monitoring overcomes limitations associated with manual audit but acceptability to health workers varies and may depend on culture of the ward and the nature of the system. Objectives: Evaluate the acceptability of a new fifth type electronic monitoring system to frontline health workers in a National Health Service trust in the UK. Methods: Qualitative interviews with 11 informants following 12 months experience using an electronic monitoring system. Results: Informants recognised the importance of hand hygiene and embraced technology to improve adherence. Barriers to hand hygiene adherence included heavy workload, dealing with emergencies and ergonomic factors related to placement of alcohol dispensers. Opinions about the validity of the automated readings were conflicting. Some health workers thought they were accurate. Others reported problems associated with differences in the intelligence of the system and their own clinical decisions. Opinions about feedback were diverse. Some health workers thought the system increased personal accountability for hand hygiene. Others ignored feedback on suboptimal performance or ignored the data altogether. It was hard for health workers to understand why the system registered some instances of poor performance because feedback did not allow omissions in hand hygiene to be related to the context of care. Conclusion: Electronic monitoring can be very well tolerated despite some limitations. Further research needs to explore different reactions to feedback and how often clinical emergencies arise. Electronic and manual audit have complementary strengths

A multifaceted approach to investigating pre-task planning effects on paired oral test performance

Despite the growing popularity of paired format speaking assessments, the effects of pre-task planning time on performance in these formats are not yet well understood. For example, some studies have revealed the benefits of planning but others have not. Using a multifaceted approach including analysis of the process of speaking performance, the aim of this paper is to investigate the effect of pre-task planning in a paired format. Data were collected from 32 students who carried out two decision-making tasks in pairs, under planned and unplanned conditions. The study used analyses of rating scores, discourse analytic measures, and conversation analysis (CA) of test-taker discourse to gain insight into co-constructing processes. A post-test questionnaire was also administered to understand the participants’ perceptions toward planned and unplanned interactions. The results from rating scores and discourse analytic measures revealed that planning had limited effect on performance, and analysis of the questionnaires did not indicate clear differences between the two conditions. CA, however, identified the possibility of a contrastive mode of discourse under the two planning conditions, raising concerns that planning might actually deprive test-takers of the chance to demonstrate their abilities to interact collaboratively

CGRP, adrenomedullin and adrenomedullin 2 display endogenous GPCR agonist bias in primary human cardiovascular cells.

Agonist bias occurs when different ligands produce distinct signalling outputs when acting at the same receptor. However, its physiological relevance is not always clear. Using primary human cells and gene editing techniques, we demonstrate endogenous agonist bias with physiological consequences for the calcitonin receptor-like receptor, CLR. By switching the receptor-activity modifying protein (RAMP) associated with CLR we can "re-route" the physiological pathways activated by endogenous agonists calcitonin gene-related peptide (CGRP), adrenomedullin (AM) and adrenomedullin 2 (AM2). AM2 promotes calcium-mediated nitric oxide signalling whereas CGRP and AM show pro-proliferative effects in cardiovascular cells, thus providing a rationale for the expression of the three peptides. CLR-based agonist bias occurs naturally in human cells and has a fundamental purpose for its existence. We anticipate this will be a starting point for more studies into RAMP function in native environments and their importance in endogenous GPCR signalling

Engineering a Model Cell for Rational Tuning of GPCR Signaling.

G protein-coupled receptor (GPCR) signaling is the primary method eukaryotes use to respond to specific cues in their environment. However, the relationship between stimulus and response for each GPCR is difficult to predict due to diversity in natural signal transduction architecture and expression. Using genome engineering in yeast, we constructed an insulated, modular GPCR signal transduction system to study how the response to stimuli can be predictably tuned using synthetic tools. We delineated the contributions of a minimal set of key components via computational and experimental refactoring, identifying simple design principles for rationally tuning the dose response. Using five different GPCRs, we demonstrate how this enables cells and consortia to be engineered to respond to desired concentrations of peptides, metabolites, and hormones relevant to human health. This work enables rational tuning of cell sensing while providing a framework to guide reprogramming of GPCR-based signaling in other systems.BBSR