The development of different brain regions involves the coordinated control of proliferation and cell fate specification along and across the neuraxis. Here, we identify Plxdc2 as a novel regulator ...of these processes, using in ovo electroporation and in vitro cultures of mammalian cells. Plxdc2 is a type I transmembrane protein with some homology to nidogen and to plexins. It is expressed in a highly discrete and dynamic pattern in the developing nervous system, with prominent expression in various patterning centres. In the chick neural tube, where Plxdc2 expression parallels that seen in the mouse, misexpression of Plxdc2 increases proliferation and alters patterns of neurogenesis, resulting in neural tube thickening at early stages. Expression of the Plxdc2 extracellular domain alone, which can be cleaved and shed in vivo, is sufficient for this activity, demonstrating a cell non-autonomous function. Induction of proliferation is also observed in cultured embryonic neuroepithelial cells (ENCs) derived from E9.5 mouse neural tube, which express a Plxdc2-binding activity. These experiments uncover a direct molecular activity of Plxdc2 in the control of proliferation, of relevance in understanding the role of this protein in various cancers, where its expression has been shown to be altered. They also implicate Plxdc2 as a novel component of the network of signalling molecules known to coordinate proliferation and differentiation in the developing nervous system.
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Financial advisors, poker players, hedge fund traders, fund-raisers, sports agents, credit counselors and commissioned salespeople all deal with one central concern in their jobs: money. In Money at ...Work, Kevin Delaney explores how we think about money and, particularly, how our jobs influence that thinking. By spotlighting people for whom money is the focus of their work, Delaney illuminates how the daily practices experienced in different jobs create distinct ways of thinking and talking about money and how occupations and their work cultures carry important symbolic, material, and practical messages about money. Delaney takes us deep inside the cultures of these 'moneyed' workers, using both interviews and first-hand observations of many of these occupations. From hedge fund trading rooms in New York, to poker players at work in Las Vegas casinos, to a Christian money retreat in a monastery in rural Pennsylvania Delaney illustrates how the underlying economic conditions of various occupations and careers produce what he calls money cultures, or ways of understanding the meaning of money, which in turn shape one's economic outlook. Key to this is how some professionals, such as debt counselors, think very differently than say poker players in their regard to money - Delaney argues that it is the structure of these professions themselves that in turn influences monetary attitudes. Fundamentally, Money at Work shows that what people do for a living has a profound effect on how people conceive of money both at work and in their home lives, making clear the connections between the economic and the social, shedding light on some of our most basic values. At a time when conversations about money are increasingly important, Delaney shows that we do not merely learn our attitudes toward money in childhood, but we also learn important money lessons from the work that we do.
For nearly 50 years, the vision of using single molecules in circuits has been seen as providing the ultimate miniaturization of electronic chips. An advanced example of such a molecular electronics ...chip is presented here, with the important distinction that the molecular circuit elements play the role of general-purpose single-molecule sensors. The device consists of a semiconductor chip with a scalable array architecture. Each array element contains a synthetic molecular wire assembled to span nanoelectrodes in a current monitoring circuit. A central conjugation site is used to attach a single probe molecule that defines the target of the sensor. The chip digitizes the resulting picoamp-scale current-versus-time readout from each sensor element of the array at a rate of 1,000 frames per second. This provides detailed electrical signatures of the single-molecule interactions between the probe and targets present in a solution-phase test sample. This platform is used to measure the interaction kinetics of single molecules, without the use of labels, in a massively parallel fashion. To demonstrate broad applicability, examples are shown for probe molecule binding, including DNA oligos, aptamers, antibodies, and antigens, and the activity of enzymes relevant to diagnostics and sequencing, including a CRISPR/Cas enzyme binding a target DNA, and a DNA polymerase enzyme incorporating nucleotides as it copies a DNA template. All of these applications are accomplished with high sensitivity and resolution, on a manufacturable, scalable, all-electronic semiconductor chip device, thereby bringing the power of modern chips to these diverse areas of biosensing.
Herbivory, mechanical injury or pathogen infestation to vegetative tissues can induce volatile organic compounds (VOCs) production, which can provide defensive functions to injured and uninjured ...plants. In our studies with ‘McNeal’ wheat, ‘Otana’ oat, and ‘Harrington’ barley, plants that were mechanically injured, attacked by either of two
Oulema spp. (
melanopus or
cyanella) beetles, or infected by one of the three
Fusarium spp. (
graminearum,
avenaceum, or
culmorum), had significant VOC induction compared to undamaged plants. Mechanical injury to the main stem or one leaf caused the induction of one green leaf volatile (GLV) – (
Z)-3-hexenol, and three terpenes (
β-linalool,
β-caryophyllene, and
α-pinene) with all three grasses; wheat and barley also showed
β-linalool oxide induction. The blend of induced VOCs after
Fusarium spp. infestation or
Oulema spp. herbivory was dominated by GLVs ((
Z)-3-hexenal, (
E)-2-hexenal, (
E)-2-hexenol, (
Z)-3-hexenyl acetate, and 1-hexenyl acetate) and
β-linalool and
β-caryophyllene; beetle herbivory also induced
(
E
)-
β-farnesene. Different ratios of individual VOCs were induced between the two
Oulema spp. for each cereal grass and different ratios across the three cereals for each beetle species. Also, different ratios of individual VOCs were induced between the three
Fusarium spp. for each cereal grass and different ratios across the three cereals for each fungal pathogen species. Our results are preliminary since we could not simultaneously measure VOC induction from controls with each of the ten different injury treatments for each of the three cereals. However, the comparison of mechanical injury, insect herbivory, and fungal infection has not been previously examined with VOC responses from three different plant species within the same family. Also, our work suggests large qualitative and quantitative overlap of VOC induction from plants of all three cereals having beetle herbivory injury when compared to infection injury from necrotrophic fungal pathogens.
Fusarium infection of maize leaves and/or roots through the soil can stimulate the emission of volatile organic compounds (VOCs). It is also well known that VOC emission from maize plants can repel ...or attract pests. In our experiments, we studied VOC induction responses of
Zea mays L. ssp.
mays cv. ‘Prosna’ having
Fusarium infection (mix of four species) in leaves or roots, then tested for VOC induction of uninfected neighboring plants, and finally examined wind-tunnel behavioral responses of the adult cereal leaf beetle,
Oulema melanopus L. (
Chrysomelidae:
Coleoptera) behavior to four induced VOCs. In the first part of our experiment, we confirmed that several green leaf volatiles (GLVs; (
Z)-3-hexenal, (
E)-2-hexenal, (
Z)-3-hexen-1-ol, (
E)-2-hexen-1-ol, (
Z)-3-hexen-1-yl acetate, 1-hexyl acetate), terpenes (β-pinene, β-myrcene,
Z-ocimene, linalool, β-caryophyllene), and shikimic acid pathway derivatives (benzyl acetate, methyl salicylate, indole) were positively induced from maize plants infected by
Fusarium spp. The quantities of induced VOCs were higher at 7
d than 3
d post-infection and greater when plants were infected with
Fusarium on leaves rather than through soil. In the second part of our experiment, uninfected maize plants also showed significantly positive induction of several VOCs when neighboring an infected plant where the degree of induction was negatively related to the distance from the infected plant. In the third part of our experiment, a Y-tube bioassay was used to evaluate upwind orientation of adult cereal leaf beetles to four individual VOCs. Female and male
O. melanopus were significantly attracted to the GLVs (
Z)-3-hexenal and (
Z)-3-hexenyl acetate, and the terpenes linalool and β-caryophyllene. Our results indicate that a pathogen can induce several VOCs in maize plants that also induce VOCs in neighboring uninfected plants, though VOC induction could increase the range at which an insect pest species is attracted to VOC inducing plants.
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•We estimate phylogenies and chronograms for 42 of 94 species of the montium group.•20 nuclear loci suffice to produce well-resolved Bayesian phylogenetic estimates.•3 non-overlapping ...sets of 20 loci produce slightly discordant Bayesian phylogenies.•Maximum likelihood and bootstrap analyses of 60 loci reinforce these uncertainties.•Divergence time estimates depend critically on difficult-to-test prior assumptions.
The Drosophila montium species group is a clade of 94 named species, closely related to the model species D. melanogaster. The montium species group is distributed over a broad geographic range throughout Asia, Africa, and Australasia. Species of this group possess a wide range of morphologies, mating behaviors, and endosymbiont associations, making this clade useful for comparative analyses. We use genomic data from 42 available species to estimate the phylogeny and relative divergence times within the montium species group, and its relative divergence time from D. melanogaster. To assess the robustness of our phylogenetic inferences, we use 3 non-overlapping sets of 20 single-copy coding sequences and analyze all 60 genes with both Bayesian and maximum likelihood methods. Our analyses support monophyly of the group. Apart from the uncertain placement of a single species, D. baimaii, our analyses also support the monophyly of all seven subgroups proposed within the montium group. Our phylograms and relative chronograms provide a highly resolved species tree, with discordance restricted to estimates of relatively short branches deep in the tree. In contrast, age estimates for the montium crown group, relative to its divergence from D. melanogaster, depend critically on prior assumptions concerning variation in rates of molecular evolution across branches, and hence have not been reliably determined. We discuss methodological issues that limit phylogenetic resolution – even when complete genome sequences are available – as well as the utility of the current phylogeny for understanding the evolutionary and biogeographic history of this clade.
Sociological research has long been interested in inequalities generated by and within educational institutions. Although relatively rich as a literature, less analytic focus has centered on ...educational mobility and inequality experiences within graduate training specifically. In this article, we draw on a combination of survey and open-ended qualitative data from approximately 450 graduate students in the discipline of sociology to analyze graduate school pipeline divergences for first-generation and working-class students and the implications for inequalities in tangible resources, advising and support, and a sense of isolation. Our results point to an important connection between private undergraduate institutional enrollment and higher-status graduate program attendance—a pattern that undercuts social-class mobility in graduate training and creates notable precarities in debt, advising, and sense of belonging for first-generation and working-class graduate students. We conclude by discussing the unequal pathways revealed and their implications for merit and mobility, graduate training, and opportunity within our and other disciplines.
► Nerium oleander experiences post-injury indirect photosynthetic reductions. ► A negative exponential relationship: photosynthetic rate with leaf injury intensity. ► First study to show high ...indirect photosynthetic reductions at low chewing levels. ► Ci (intercellular CO2) increases with leaf injury intensity: non-stomatal limitation. ► Light-harvesting photosynthetic impairment prior to post-injury stomatal closure.
Variable indirect photosynthetic rate (Pn) responses occur on injured leaves after insect herbivory. It is important to understand factors that influence indirect Pn reductions after injury. The current study examines the relationship between gas exchange and chlorophyll a fluorescence parameters with injury intensity (% single leaf tissue removal) from clipping or Spodoptera eridania Stoll (Noctuidae) herbivory on Nerium oleander L. (Apocynaceae). Two experiments showed intercellular CO2 increases but Pn and stomatal conductance reductions with increasing injury intensity, suggesting non-stomatal Pn limitation. Also, Pn recovery was incomplete at 3d post-injury. This is the first report of a negative exponential Pn impairment function with leaf injury intensity to suggest high N. oleander leaf sensitivity to indirect Pn impairment. Negative linear functions occurred between most other gas exchange and chlorophyll a fluorescence parameters with injury intensity. The degree of light harvesting impairment increased with injury intensity via lower (1) photochemical efficiency indicated lower energy transfer efficiency from reaction centers to PSII, (2) photochemical quenching indicated reaction center closure, and (3) electron transport rates indicated less energy traveling through PSII. Future studies can examine additional mechanisms (mesophyll conductance, carbon fixation, and cardenolide induction) to cause N. oleander indirect leaf Pn reductions after injury.
Variation in the early environment has the potential to permanently alter offspring behavior and development. We have previously shown that naturally occurring variation in biparental care of ...offspring in the prairie vole is related to differences in social behavior of the offspring. It was not, however, clear whether the behavioral differences seen between offspring receiving high compared to low amounts of parental care were the result of different care experiences or were due to shared genetics with their high-contact or low-contact parents. Here we use cross-fostering methods to determine the mode of transmission of alloparental behavior and oxytocin receptor (OTR) and vasopressin V1a receptor (V1aR) binding from parent to offspring. Offspring were cross-fostered or in-fostered on postnatal day 1 and parental care received was quantified in the first week postpartum. At weaning, offspring underwent an alloparental care test and brains were then collected from all parents and offspring to examine OTR and V1aR binding. Results indicate that alloparental behavior of offspring was predicted by the parental behavior of their rearing parents. Receptor binding for both OTR and V1aR tended to be predicted by the genetic mothers for female offspring and by the genetic fathers for male offspring. These findings suggest a different, sex-dependent, role of early experience and genetics in shaping behavior compared to receptor distribution and support the notion of sex-dependent outcomes.
Social science research has long recognized the relevance of socioeconomic background for mobility and inequality. In this article we interrogate how and why working-class and first-generation ...backgrounds are especially meaningful and take as our case in point the professoriate and the discipline of sociology, – i.e., a field that intellectually prioritizes attention to group inequality and that arguably offers a conservative empirical test compared to other academic fields. Our analyses, which draw on unique survey items and open-ended qualitative materials from nearly 1,000 academic sociologists, reveal significant background divergences in academic job attainment, tied partly to educational background. Moreover, and especially unique and important, findings demonstrate significant consequences across several dimensions of inequality including compensation and economic precarity, professional visibility, and isolation at departmental, college or university, and professional levels. We conclude by highlighting how our discussion and results contribute in important ways to broader sociological concerns surrounding mobility, group disadvantage, and social closure.
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