Lentiviral vectors with amplified beta cell-specific gene expression.

An important goal of gene therapy is to be able to deliver genes, so that they express in a pattern that recapitulates the expression of an endogenous cellular gene. Although tissue-specific promoters confer selectivity, in a vector-based system, their activity may be too weak to mediate detectable levels in gene-expression studies. We have used a two-step transcriptional amplification system to amplify gene expression from lentiviral vectors using the human insulin promoter. In this system, the human insulin promoter drives expression of a potent synthetic transcription activator (the yeast GAL4 DNA-binding domain fused to the activation domain of the Herpes simplex virus-1 VP16 activator), which in turn activates a GAL4-responsive promoter, driving the enhanced green fluorescent protein reporter gene. Vectors carrying the human insulin promoter did not express in non-beta-cell lines, but expressed in murine insulinoma cell lines, indicating that the human insulin promoter was capable of conferring cell specificity of expression. The insulin-amplifiable vector was able to amplify gene expression five to nine times over a standard insulin-promoter vector. In primary human islets, gene expression from the insulin-promoted vectors was coincident with insulin staining. These vectors will be useful in gene-expression studies that require a detectable signal and tissue specificity

Novel 16S rRNA methyltransferase RmtE3 in acinetobacter baumannii ST79.

Introduction. The 16S rRNA methyltransferase (16S RMTase) gene armA is the most common mechanism conferring high-level aminoglycoside resistance in Acinetobacter baumannii, although rmtA, rmtB, rmtC, rmtD and rmtE have also been reported.Hypothesis/Gap statement. The occurrence of 16S RMTase genes in A. baumannii in the UK and Republic of Ireland is currently unknown.Aim. To identify the occurrence of 16S RMTase genes in A. baumannii isolates from the UK and the Republic of Ireland between 2004 and 2015.Methodology. Five hundred and fifty pan-aminoglycoside-resistant A. baumannii isolates isolated from the UK and the Republic of Ireland between 2004 and 2015 were screened by PCR to detect known 16S RMTase genes, and then whole-genome sequencing was conducted to screen for novel 16S RMTase genes.Results. A total of 96.5 % (531/550) of isolates were positive for 16S RMTase genes, with all but 1 harbouring armA (99.8 %, 530/531). The remaining isolates harboured rmtE3, a new rmtE variant. Most (89.2 %, 473/530) armA-positive isolates belonged to international clone II (ST2), and the rmtE3-positive isolate belonged to ST79. rmtE3 shared a similar genetic environment to rmtE2 but lacked an ISCR20 element found upstream of rmtE2.Conclusion. This is the first report of rmtE in A. baumannii in Europe; the potential for transmission of rmtE3 to other bacterial species requires further research

Estimating the furrow infiltration characteristic from a single advance point

Management and control of surface irrigation, in particular furrow irrigation, is limited by spatio-temporal soil infiltration variability as well as the high cost and time associated with collecting intensive field data for estimation of the infiltration characteristics. Recent work has proposed scaling the commonly used infiltration function by using a model infiltration curve and a single advance point for every other furrow in an irrigation event. Scaling factors were calculated for a series of furrows at two sites and at four points down the length of the field (0.25 L, 0.5 L, 0.75 L and L). Differences in the value of the scaling factor with distance were found to be a function of the shape of the advance curves. It is concluded that use of points early in the advance results in a substantial loss of accuracy and should be avoided. The scaling factor was also strongly correlated with the furrow-wetted perimeter suggesting that the scaling is an appropriate way of both predicting and accommodating the effect of the hydraulic variability

Non Abelian Geometrical Tachyon

We investigate the dynamics of a pair of coincident D5 branes in the background of $k$ NS5 branes. It has been proposed by Kutasov that the system with a single probing D-brane moving radially in this background is dual to the tachyonic DBI action for a non-BPS Dp brane. We extend this proposal to the non-abelian case and find that the duality still holds provided one promotes the radial direction to a matrix valued field associated with a non-abelian geometric tachyon and a particular parametrization for the transverse scalar fields is chosen. The equations of motion of a pair of coincident D5 branes moving in the NS5 background are determined. Analytic and numerical solutions for the pair are found in certain simplified cases in which the U(2) symmetry is broken to $U(1) \times U(1)$ corresponding to a small transverse separation of the pair. For certain range of parameters these solutions describe periodic motion of the centre of mass of the pair 'bouncing off' a finite sized throat whose minimum size is limited by the D5 branes separation.Comment: 18 pages, 2 figures, PdfLatex: references added.accepted for publication in JHE

Production of hybrid granitic magma at the advancing front of basaltic underplating: Inferences from the Sesia Magmatic System (south-western Alps, Italy)

The Permian Sesia Magmatic System of the southwestern Alps displays the plumbing system beneath a Permian caldera, including a deep crustal gabbroic complex, upper crustal granite plutons and a bimodal volcanic field dominated by rhyolitic tuff filling the caldera. Isotopic compositions of the deep crustal gabbro overlap those of coeval andesitic basalts, whereas granites define a distinct, more radiogenic cluster (Sri 480.708 and 0.710, respectively). AFC computations starting from the best mafic candidate for a starting melt show that Nd and Sr isotopic compositions and trace elements of andesitic basalts may be modeled by reactive bulk assimilation of 4830% of partially depleted crust and 4815%\u201330% gabbro fractionation. Trace elements of the deep crustal gabbro cumulates require a further 4860% fractionation of the andesitic basalt and loss of 4840% of silica-rich residual melt. The composition of the granite plutons is consistent with a mixture of relatively constant proportions of residual melt delivered from the gabbro and anatectic melt. Chemical and field evidence leads to a conceptual modelwhich links the production of the two granitic components to the evolution of theMafic Complex. During the growth of the Mafic Complex, progressive incorporation of packages of crustal rocks resulted in a roughly steady state rate of assimilation. Anatectic granite originates in the hot zone of melting crust located above the advancing mafic intrusion. Upward segregation of anatectic melts facilitates the assimilation of the partially depleted restite by stoping. At each cycle of mafic intrusion and incorporation, residual and anatectic melts are produced in roughly constant proportions, because the amount of anatectic melt produced at the roof is a function of volume and latent heat of crystallization of the underplated mafic melt which in turn produces proportional amounts of hybrid gabbro cumulates and residualmelt. Such a process can explain the restricted range in isotopic compositions of most rhyolitic and granitic rocks of the Permo-Carboniferous province of Europe and elsewhere

Down-regulation of hypothalamic corticotropin-releasing hormone messenger ribonucleic acid (mRNA) precedes early-life experience-induced changes in hippocampal glucocorticoid receptor mRNA.

Early-life experiences, including maternal interaction, profoundly influence hormonal stress responses during adulthood. In rats, daily handling during a critical neonatal period leads to a significant and permanent modulation of key molecules that govern hormonal secretion in response to stress. Thus, hippocampal glucocorticoid receptor (GR) expression is increased, whereas hypothalamic CRH-messenger RNA (mRNA) levels and stress-induced glucocorticoid release are reduced in adult rats handled early in life. Recent studies have highlighted the role of augmented maternal sensory input to handled rats as a key determinant of these changes. However, the molecular mechanisms, and particularly the critical, early events leading from enhanced sensory experience to long-lasting modulation of GR and CRH gene expression, remain largely unresolved. To elucidate the critical primary genes governing this molecular cascade, we determined the sequence of changes in GR-mRNA levels and in hypothalamic and amygdala CRH-mRNA expression at three developmental ages, and the temporal relationship between each of these changes and the emergence of reduced hormonal stress-responses. Down-regulation of hypothalamic CRH-mRNA levels in daily-handled rats was evident already by postnatal day 9, and was sustained through postnatal days 23 and 45, i.e. beyond puberty. In contrast, handling-related up-regulation of hippocampal GR-mRNA expression emerged subsequent to the 23rd postnatal day, i.e. much later than changes in hypothalamic CRH expression. The hormonal stress response of handled rats was reduced starting before postnatal day 23. These findings indicate that early, rapid, and persistent changes of hypothalamic CRH gene expression may play a critical role in the mechanism(s) by which early-life experience influences the hormonal stress-response long-term

Mesoscale fronts as foraging habitats: composite front mapping reveals oceanographic drivers of habitat use for a pelagic seabird

The oceanographic drivers of marine vertebrate habitat use are poorly understood yet fundamental to our knowledge of marine ecosystem functioning. Here, we use composite front mapping and high-resolution GPS tracking to determine the significance of mesoscale oceanographic fronts as physical drivers of foraging habitat selection in northern gannets Morus bassanus. We tracked 66 breeding gannets from a Celtic Sea colony over 2 years and used residence time to identify area-restricted search (ARS) behaviour. Composite front maps identified thermal and chlorophyll-a mesoscale fronts at two different temporal scales—(i) contemporaneous fronts and (ii) seasonally persistent frontal zones. Using generalized additive models (GAMs), with generalized estimating equations (GEE-GAMs) to account for serial autocorrelation in tracking data, we found that gannets do not adjust their behaviour in response to contemporaneous fronts. However, ARS was more likely to occur within spatially predictable, seasonally persistent frontal zones (GAMs). Our results provide proof of concept that composite front mapping is a useful tool for studying the influence of oceanographic features on animal movements. Moreover, we highlight that frontal persistence is a crucial element of the formation of pelagic foraging hotspots for mobile marine vertebrates

The Firefighter Problem: A Structural Analysis

We consider the complexity of the firefighter problem where b>=1 firefighters are available at each time step. This problem is proved NP-complete even on trees of degree at most three and budget one (Finbow et al.,2007) and on trees of bounded degree b+3 for any fixed budget b>=2 (Bazgan et al.,2012). In this paper, we provide further insight into the complexity landscape of the problem by showing that the pathwidth and the maximum degree of the input graph govern its complexity. More precisely, we first prove that the problem is NP-complete even on trees of pathwidth at most three for any fixed budget b>=1. We then show that the problem turns out to be fixed parameter-tractable with respect to the combined parameter "pathwidth" and "maximum degree" of the input graph

Checkpoints are blind to replication restart and recombination intermediates that result in gross chromosomal rearrangements

Replication fork inactivation can be overcome by homologous recombination, but this can cause gross chromosomal rearrangements that subsequently missegregate at mitosis, driving further chromosome instability. It is unclear when the chromosome rearrangements are generated and whether individual replication problems or the resulting recombination intermediates delay the cell cycle. Here we have investigated checkpoint activation during HR-dependent replication restart using a site-specific replication fork-arrest system. Analysis during a single cell cycle shows that HR-dependent replication intermediates arise in S phase, shortly after replication arrest, and are resolved into acentric and dicentric chromosomes in G2. Despite this, cells progress into mitosis without delay. Neither the DNA damage nor the intra-S phase checkpoints are activated in the first cell cycle, demonstrating that these checkpoints are blind to replication and recombination intermediates as well as to rearranged chromosomes. The dicentrics form anaphase bridges that subsequently break, inducing checkpoint activation in the second cell cycle

The Earliest Origins of Genetic Nurture: The Prenatal Environment Mediates the Association Between Maternal Genetics and Child Development

Observed genetic associations with educational attainment may be due to direct or indirect genetic influences. Recent work highlights genetic nurture, the potential effect of parents’ genetics on their child’s educational outcomes via rearing environments. To date, few mediating childhood environments have been tested. We used a large sample of genotyped mother–child dyads (N = 2,077) to investigate whether genetic nurture occurs via the prenatal environment. We found that mothers with more education-related genes are generally healthier and more financially stable during pregnancy. Further, measured prenatal conditions explain up to one third of the associations between maternal genetics and children’s academic and developmental outcomes at the ages of 4 to 7 years. By providing the first evidence of prenatal genetic nurture and showing that genetic nurture is detectable in early childhood, this study broadens our understanding of how parental genetics may influence children and illustrates the challenges of within-person interpretation of existing genetic associations