Diversity of transposable elements and repeats in a 600 kb region of the fly Calliphora vicina.

RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.BACKGROUND: Transposable elements (TEs) are a very dynamic component of eukaryotic genomes with important implications (e.g., in evolution) and applications (e.g., as transgenic tools). They also represent a major challenge for the assembly and annotation of genomic sequences. However, they are still largely unknown in non-model species. RESULTS: Here, we have annotated the repeats and transposable elements present in a 600 kb genomic region of the blowfly Calliphora vicina (Diptera: Calliphoridae) which contains most of the achaete-scute gene complex of this species. This is the largest genomic region to be sequenced and analyzed in higher flies outside the Drosophila genus. We find that the repeat content spans at least 24% of the sequence. It includes 318 insertions classified as 3 LTR retrotransposons, 21 LINEs, 14 cut-and-paste DNA transposons, 4 helitrons and 33 unclassified repeats. CONCLUSIONS: This is the most detailed description of TEs and repeats in the Calliphoridae to date. This contribution not only adds to our knowledge about TE evolution but will also help in the annotation of repeats on Dipteran whole genome sequences

Requirement for Dynamin during Notch Signaling inDrosophilaNeurogenesis

AbstractSingling out of a unique neural precursor from a group of equivalent cells, duringDrosophilaneurogenesis, involves Notch-mediated lateral signaling. During this process, activation of the Notch signaling pathway leads to repression of neural development. Disruption of this signaling pathway results in the development of an excess of neural cells. The loss of activity of dynamin, which is encoded by the geneshibireand is required for endocytosis, results in a similar phenotype. Here we have investigated the requirement ofshibirefunction for Notch signaling during the segregation of sensory bristles on the notum of the fly. Overexpression of different constitutively active forms of Notch inshibiremutant flies indicates thatshibirefunction is not necessary for transduction of the signal downstream of Notch, even when the receptor is integrated in the plasma membrane. However, when wild-type Notch is activated by its ligand Delta, dynamin is required in both signaling and receiving cells for normal singling out of precursors. This suggests an active role of the signaling cell for ligand-mediated receptor endocytosis in the case of transmembrane ligands. We discuss the possible implications of these results for normal functioning of Notch-mediated lateral signaling

Paediatric acute lymphoblastic leukaemia and caesarean section : A report from the United Kingdom Childhood Cancer Study (UKCCS)

BACKGROUND: Reports have suggested that children born by caesarean initiated before labour onset may be at increased risk of developing acute lymphoblastic leukaemia (ALL). However, with most data being derived from case-control study interviews, information on the underpinning reasons for caesarean section is sparse, and evidence is conflicting. OBJECTIVES: Use clinical records compiled at the time of delivery to investigate the association between childhood ALL and caesarean delivery; examining timing in relation to labour onset, and reasons for the procedure. METHODS: Data are from the UK Childhood Cancer Study, a population-based case-control study conducted in the 1990s, when caesarean section rates were relatively low, in England, Scotland, and Wales. Children with ALL were individually matched to two controls on sex, date of birth, and region of residence. Information on mode of delivery and complications was abstracted from obstetric records. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using logistic regression models adjusted for matching variables and relevant covariates. RESULTS: Around 75% of the 1034 cases and 1914 controls were born through unassisted vaginal delivery. Caesarean delivery was as frequent in cases and controls (OR 1.07, 95% CI 0.84, 1.36). No association was observed between ALL and caesarean delivery either during or before labour, with adjusted ORs of 1.08 (95% CI 0.78, 1.48) and 1.09 (95% CI 0.78, 1.53), respectively. For B-cell ALL, the ORs were 1.14 (95% CI 0.81, 1.59) for caesarean during labour and 1.21 (95% CI 0.85, 1.72) for prelabour. The underpinning reasons for caesarean delivery differed between cases and controls; with preeclampsia, although very rare, being more common amongst cases born by caesarean (OR 8.91, 95% CI 1.48, 53.42). CONCLUSIONS: Our obstetric record-based study found no significant evidence that caesarean delivery increased the risk of childhood ALL, either overall or when carried out before labour

The bristle patterning genes hairy and extramacrochaetae regulate the development of structures required for flight in Diptera.

The distribution of sensory bristles on the thorax of Diptera (true flies) provides a useful model for the study of the evolution of spatial patterns. Large bristles called macrochaetes are arranged into species-specific stereotypical patterns determined via spatially discrete expression of the proneural genes achaete-scute (ac-sc). In Drosophila ac-sc expression is regulated by transcriptional activation at sites where bristle precursors develop and by repression outside of these sites. Three genes, extramacrochaetae (emc), hairy (h) and stripe (sr), involved in repression have been documented. Here we demonstrate that in Drosophila, the repressor genes emc and h, like sr, play an essential role in the development of structures forming part of the flight apparatus. In addition we find that, in Calliphora vicina a species diverged from D. melanogaster by about 100 Myr, spatial expression of emc, h and sr is conserved at the location of development of those structures. Based on these findings we argue, first, that the role emc, h and sr in development of the flight apparatus preceded their activities for macrochaete patterning; second, that species-specific variation in activation and repression of ac-sc expression is evolving in parallel to establish a unique distribution of macrochaetes in each species

Generation of medial and lateral dorsal body domains by the pannier gene of Drosophila

The pannier (pnr) gene encodes a GATA transcription factor and acts in several developmental processes in Drosophila, including embryonic dorsal closure, specification of cardiac cells and bristle determination. We show that pnr is expressed in the mediodorsal parts of thoracic and abdominal segments of embryos, larvae and adult flies. Its activity confers cells with specific adhesion properties that make them immiscible with non-expressing cells. Thus there are two genetic domains in the dorsal region of each segment: a medial (MED) region where pnr is expressed and a lateral (LAT) region where it is not. The homeobox gene iroquois (iro) is expressed in the LAT region. These regions are not formed by separate polyclones of cells, but are defined topographically. We show that ectopic pnr in the wing induces MED thoracic development, indicating that pnr specifies the identity of the MED regions. Correspondingly, when pnr is removed from clones of cells in the MED domain, they sort out and apparently adopt the LAT fate. We propose that (1) the subdivision into MED and LAT regions is a general feature of the Drosophila body plan and (2) pnr is the principal gene responsible for this subdivision. We argue that pnr acts like a classical selector gene but differs in that its expression is not propagated through cell divisions.Dirección General de Investigación Científica y Técnica and the Fundación Ramón ArecesPeer Reviewe

A novel two-laser interface for coupling capillary electrochromatography with ion-trap time-of-flight mass spectrometry

An interface has been developed for the hyphenation of capillary electrochromatography (CEC) with mass spectrometry (MS). Chromatographic eluate vaporization and selective analyte ionization occur within a quadrupole ion-trap, which permits significant instrument simplification when compared with the atmospheric pressure interfaces typically used for CEC-MS. Vaporization is achieved using laser desorption at 1064 nm while ionization is accomplished through UV photoionization. This two-step approach, through ionization laser wavelength selection, can provide ultratrace analysis with high selectivity. The mass spectrometer is a hybrid ion-trap time-of-flight (TOF) instrument in which the ion-trap is used in radio frequency-only mode, with DC-pulse ejection, to provide decoupling of the different timescales required for CEC separation and TOF mass analysis. The ion-trap is capable of accumulating ions over multiple laser shots. The mass resolution of the demonstration instrument was circa 1500. Preliminary CEC-MS runs have been recorded for mixtures containing polycyclic aromatic hydrocarbons. A concentration detection limit of 500 nM, for naphthalene in acetonitrile, has been determined for the interface

Allergy and Risk of Childhood Leukaemia: Results from the UKCCS

We investigated the relationship between childhood leukaemia and preceding history of allergy. A nationwide case-control study of childhood cancers was conducted in the United Kingdom with population-based sampling of cases (n = 839) and controls (n = 1,337), matched on age, sex and region of residence. Information about clinically diagnosed allergies was obtained from primary care records. More than a third of subjects had at least one allergy diagnosed prior to leukaemia diagnosis (cases) or pseudo-diagnosis (controls). For both total acute lymphoblastic leukaemia (ALL) and common-ALL/precursor B-cell ALL (c-ALL), a history of eczema was associated with a 30% significant reduction in risk: the odds ratios (OR) and 95% confidence intervals (CI) were 0.70 (0.51-0.97) and 0.68 (0.48-0.98), respectively. Similar associations were observed for hayfever (OR = 0.47; 95% CI: 0.26-0.85 and OR = 0.62; 95% CI: 0.33-1.16 for ALL and c-ALL, respectively). No such patterns were seen either for asthma and ALL, or for any allergy and acute myeloid leukaemia. A comparative analysis of primary care records with parents recall of allergy revealed only moderate agreement with contemporaneous clinical diagnoses for both cases and controls - confirming the unreliability of parental report at interview. Our finding of a reciprocal relationship between allergy and ALL in children is compatible with the hypothesis that a dysregulated immune response is a critical determinant of childhood ALL

Perinatal outcomes after admission with COVID-19 in pregnancy:a UK national cohort study

There are few population-based studies of sufficient size and follow-up duration to have reliably assessed perinatal outcomes for pregnant women hospitalised with SARS-CoV-2 infection. The United Kingdom Obstetric Surveillance System (UKOSS) covers all 194 consultant-led UK maternity units and included all pregnant women admitted to hospital with an ongoing SARS-CoV-2 infection. Here we show that in this large national cohort comprising two years’ active surveillance over four SARS-CoV-2 variant periods and with near complete follow-up of pregnancy outcomes for 16,627 included women, severe perinatal outcomes were more common in women with moderate to severe COVID-19, during the delta dominant period and among unvaccinated women. We provide strong evidence to recommend continuous surveillance of pregnancy outcomes in future pandemics and to continue to recommend SARS-CoV-2 vaccination in pregnancy to protect both mothers and babies