Environmental and molecular analysis of the floral transition in the lower eudicot Aquilegia formosa

<p>Abstract</p> <p>Background</p> <p>Flowering is a critical transition in plant development, the timing of which can have considerable fitness consequences. Until recently, research into the genetic control of flowering time and its associated developmental changes was focused on core eudicots (for example, Arabidopsis) or monocots (for example, <it>Oryza</it>). Here we examine the flowering response of <it>Aquilegia formosa</it>, a member of the eudicot order Ranunculales that is emerging as an important model for the investigation of plant ecology and evolution.</p> <p>Results</p> <p>We have determined that <it>A. formosa </it>has a strong vernalization requirement but little or no photoperiod response, making it a day neutral (DN) plant. Consistent with this, the <it>Aquilegia </it>homolog of <it>FLOWERING LOCUS T </it>(<it>AqFT</it>) is expressed in both long and short days but surprisingly, the locus is expressed before the transition to flowering. <it>In situ </it>hybridizations with homologs of several Arabidopsis Floral Pathway Integrators (FPIs) do not suggest conserved functions relative to Arabidopsis, the potential exceptions being <it>AqLFY </it>and <it>AqAGL24.2</it>.</p> <p>Conclusions</p> <p>In <it>Aquilegia</it>, vernalization is critical to flowering but this signal is not strictly required for the transcriptional activation of <it>AqFT</it>. The expression patterns of <it>AqLFY </it>and <it>AqAGL24.2 </it>suggest a hypothesis for the development of <it>Aquilegia</it>'s determinate inflorescence whereby their differential expression controls the progression of each meristem from inflorescence to floral identity. Interestingly, none of the <it>Aquilegia </it>expression patterns are consistent with a function in floral repression which, combined with the lack of a <it>FLC </it>homolog, means that new candidate genes must be identified for the control of vernalization response in <it>Aquilegia</it>.</p

Nanomaterials for stimulating nerve growth

Despite recent advances in supportive care for spinal cord injury (SCI), there is a great need for treatments that can improve the neurological outcome (1). After SCI, there is essentially no regrowth of axons beyond the point of the lesion, leaving intact, although nonfunctional, circuits below the site of injury. We discuss the potential for functional recovery from SCI by using nanomaterials to restore these dysfunctional circuits through a combination of artificial connections and devices to help stimulate motor and sensory recovery

In the Light of Evolution: A Reevaluation of Conservation in the CO–FT Regulon and Its Role in Photoperiodic Regulation of Flowering Time

In order to maximize reproductive success, plants have evolved different strategies to control the critical developmental shift marked by the transition to flowering. As plants have adapted to diverse environments across the globe, these strategies have evolved to recognize and respond to local seasonal cues through the induction of specific downstream genetic pathways, thereby ensuring that the floral transition occurs in favorable conditions. Determining the genetic factors involved in controlling the floral transition in many species is key to understanding how this trait has evolved. Striking genetic discoveries in Arabidopsis thaliana (Arabidopsis) and Oryza sativa (rice) revealed that similar genes in both species control flowering in response to photoperiod, suggesting that this genetic module could be conserved between distantly related angiosperms. However, as we have gained a better understanding of the complex evolution of these genes and their functions in other species, another possibility must be considered: that the genetic module controlling flowering in response to photoperiod is the result of convergence rather than conservation. In this review, we show that while data clearly support a central role of FLOWERING LOCUS T (FT) homologs in floral promotion across a diverse group of angiosperms, there is little evidence for a conserved role of CONSTANS (CO) homologs in the regulation of these loci. In addition, although there is an element of conserved function for FT homologs, even this component has surprising complexity in its regulation and evolution

GP-Unet: Lesion Detection from Weak Labels with a 3D Regression Network

We propose a novel convolutional neural network for lesion detection from weak labels. Only a single, global label per image - the lesion count - is needed for training. We train a regression network with a fully convolutional architecture combined with a global pooling layer to aggregate the 3D output into a scalar indicating the lesion count. When testing on unseen images, we first run the network to estimate the number of lesions. Then we remove the global pooling layer to compute localization maps of the size of the input image. We evaluate the proposed network on the detection of enlarged perivascular spaces in the basal ganglia in MRI. Our method achieves a sensitivity of 62% with on average 1.5 false positives per image. Compared with four other approaches based on intensity thresholding, saliency and class maps, our method has a 20% higher sensitivity.Comment: Article published in MICCAI 2017. We corrected a few errors from the first version: padding, loss, typos and update of the DOI numbe

Carbon based substrates for interfacing neurons: Comparing pristine with functionalized carbon nanotubes effects on cultured neuronal networks

Pristine (as prepared) carbon nanotube (CNT) based substrates have been widely used to grow and interface neurons in culture. Nerve cells normally differentiate on CNTs and the synaptic networks, newly formed at the interface with this material, usually show an improved robustness in signal transfer. However manipulation of pristine CNTs is often prevented by their low dispersibility and tendency to aggregate in most solvents. This issue can be at least partially solved by adding solubilizing groups to the surface of CNT, which also helps improving their biocompatibility. It becomes therefore of crucial importance to determine whether chemically manipulated CNTs may maintain their performance in improving nerve signaling. Here we study and compare the impact in vitro on neuronal signaling of two classes of chemically modified multiwalled CNTs in reference to pristine CNTs, which are known to be a substrate able to boost neuronal growth and communication. We found that the extent of functionalization and the nature of the functional groups on MWNT sidewalls affect the conductivity and the biological effects of the final derivatives. This information is important for the future design of biointegrated devices

Parking and the visual perception of space

Using measured data we demonstrate that there is an amazing correspondence among the statistical properties of spacings between parked cars and the distances between birds perching on a power line. We show that this observation is easily explained by the fact that birds and human use the same mechanism of distance estimation. We give a simple mathematical model of this phenomenon and prove its validity using measured data

Sculpting neurotransmission during synaptic development by 2D nanostructured interfaces

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Polyclonal outbreak of bacteremia caused by Burkholderia cepacia complex and the presumptive role of ultrasound gel

AbstractA nosocomial polyclonal outbreak associated to bacteremia caused by different Burkholderia cepacia complex (BCC) species and clones is reported. Molecular characterization identified Burkholderia stabilis, Burkholderia contaminans, and Burkholderia ambifaria among BCC isolates obtained from patients in neonatal and adult intensive care units. BCC was also isolated from an intrinsically contaminated ultrasound gel, which constituted the presumptive BCC source. Prior BCC outbreak related to contaminated ultrasound gels have been described in the setting of transrectal prostate biopsy. Outbreak caused strains and/or clones of BCC have been reported, probably because BCC are commonly found in the natural environment; most BCC species are biofilm producers, and different species may contaminate an environmental source. The finding of multiple species or clones during the analysis of nosocomial BCC cases might not be enough to reject an outbreak from a common source

Polyclonal outbreak of bacteremia caused by Burkholderia cepacia complex and the presumptive role of ultrasound gel

AbstractA nosocomial polyclonal outbreak associated to bacteremia caused by different Burkholderia cepacia complex (BCC) species and clones is reported. Molecular characterization identified Burkholderia stabilis, Burkholderia contaminans, and Burkholderia ambifaria among BCC isolates obtained from patients in neonatal and adult intensive care units. BCC was also isolated from an intrinsically contaminated ultrasound gel, which constituted the presumptive BCC source. Prior BCC outbreak related to contaminated ultrasound gels have been described in the setting of transrectal prostate biopsy. Outbreak caused strains and/or clones of BCC have been reported, probably because BCC are commonly found in the natural environment; most BCC species are biofilm producers, and different species may contaminate an environmental source. The finding of multiple species or clones during the analysis of nosocomial BCC cases might not be enough to reject an outbreak from a common source

Super-hydrodynamic limit in interacting particle systems

This paper is a follow-up of the work initiated in [3], where it has been investigated the hydrodynamic limit of symmetric independent random walkers with birth at the origin and death at the rightmost occupied site. Here we obtain two further results: first we characterize the stationary states on the hydrodynamic time scale and show that they are given by a family of linear macroscopic profiles whose parameters are determined by the current reservoirs and the system mass. Then we prove the existence of a super-hyrdrodynamic time scale, beyond the hydrodynamic one. On this larger time scale the system mass fluctuates and correspondingly the macroscopic profile of the system randomly moves within the family of linear profiles, with the randomness of a Brownian motion.Comment: 22 page