Reshaping the brain: direct lineage conversion in the nervous system

During embryonic development, cells in an uncommitted pluripotent state undergo progressive epigenetic changes that lock them into a final restrictive differentiated state. However, recent advances have shown that not only is it possible for a fully differentiated cell to revert back to a pluripotent state, a process called nuclear reprogramming, but also that differentiated cells can be directly converted from one class into another without generating progenitor intermediates, a process known as direct lineage conversion. In this review, we discuss recent progress made in direct lineage reprogramming of differentiated cells into neurons and discuss some of the therapeutic implications of the findings

The quality of writing tasks and students' use of academic language in Spanish

This study investigates the quality of the writing tasks assigned to native Spanish speakers in bilingual (Spanish-English) contexts, and the relationship between task quality and students' use of an academic register in their native language. Fifty-six language arts tasks were collected from 26 grade 4 and 5 teachers, and four student writing samples were collected in response to each task (N = 224). Multilevel modeling revealed that variation in students' use of key features of academic language in their writing was associated with the cognitive demand of writing tasks. Findings suggest that students' opportunities to respond to challenging tasks when writing in their native language are rare and that the rigor of writing tasks may relate to students' production and development of academic language. © 2012 by The University of Chicago. All rights reserved

Ctip2 Controls the Differentiation of Medium Spiny Neurons and the Establishment of the Cellular Architecture of the Striatum

Striatal medium spiny neurons (MSN) are critically involved in motor control, and their degeneration is a principal component of Huntington's disease. We find that the transcription factor Ctip2 (also known as Bcl11b) is central to MSN differentiation and striatal development. Within the striatum, it is expressed by all MSN, although it is excluded from essentially all striatal interneurons. In the absence of Ctip2, MSN do not fully differentiate, as demonstrated by dramatically reduced expression of a large number of MSN markers, including DARPP-32, FOXP1, Chrm4, Reelin, MOR1 (mu-opioid receptor 1), glutamate receptor 1, and Plexin-D1. Furthermore, MSN fail to aggregate into patches, resulting in severely disrupted patch-matrix organization within the striatum. Finally, heterotopic cellular aggregates invade the Ctip2-/- striatum, suggesting a failure by MSN to repel these cells in the absence of Ctip2. This is associated with abnormal dopaminergic innervation of the mutant striatum and dramatic changes in gene expression, including dysregulation of molecules involved in cellular repulsion. Together, these data indicate that Ctip2 is a critical regulator of MSN differentiation, striatal patch development, and the establishment of the cellular architecture of the striatum.Stem Cell and Regenerative Biolog

Novel Subtype-Specific Genes Identify Distinct Subpopulations of Callosal Projection Neurons

Little is known about the molecular development and heterogeneity of callosal projection neurons (CPN), cortical commissural neurons that connect homotopic regions of the two cerebral hemispheres via the corpus callosum and that are critical for bilateral integration of cortical information. Here we report on the identification of a series of genes that individually and in combination define CPN and novel CPN subpopulations during embryonic and postnatal development. We used in situ hybridization analysis, immunocytochemistry, and retrograde labeling to define the layer-specific and neuron-type-specific distribution of these newly identified CPN genes across different stages of maturation. We demonstrate that a subset of these genes (e.g., Hspb3 and Lpl) appear specific to all CPN (in layers II/III and V–VI), whereas others (e.g., Nectin-3, Plexin-D1, and Dkk3) discriminate between CPN of the deep layers and those of the upper layers. Furthermore, the data show that several genes finely subdivide CPN within individual layers and appear to label CPN subpopulations that have not been described previously using anatomical or morphological criteria. The genes identified here likely reflect the existence of distinct programs of gene expression governing the development, maturation, and function of the newly identified subpopulations of CPN. Together, these data define the first set of genes that identify and molecularly subcategorize distinct populations of callosal projection neurons, often located in distinct subdivisions of the canonical cortical laminae.Stem Cell and Regenerative BiologyOther Research Uni

Spatiotemporal expression and transcriptional perturbations by long noncoding RNAs in the mouse brain

Long noncoding RNAs (lncRNAs) have been implicated in numerous cellular processes including brain development. However, the in vivo expression dynamics and molecular pathways regulated by these loci are not well understood. Here, we leveraged a cohort of 13 lncRNA-null mutant mouse models to investigate the spatiotemporal expression of lncRNAs in the developing and adult brain and the transcriptome alterations resulting from the loss of these lncRNA loci. We show that several lncRNAs are differentially expressed both in time and space, with some presenting highly restricted expression in only selected brain regions. We further demonstrate altered regulation of genes for a large variety of cellular pathways and processes upon deletion of the lncRNA loci. Finally, we found that 4 of the 13 lncRNAs significantly affect the expression of several neighboring protein-coding genes in a cis-like manner. By providing insight into the endogenous expression patterns and the transcriptional perturbations caused by deletion of the lncRNA locus in the developing and postnatal mammalian brain, these data provide a resource to facilitate future examination of the specific functional relevance of these genes in neural development, brain function, and disease.National Science Foundation (U.S.) (Postdoctoral Research Fellowship in Biology DBI-0905973

Growing sweet potatoes [Ipomoea batatas (L.) Lam.)] for their greens and the impact on storage roots

Sweet potato greens are an underused but highly nutritious vegetable that grows well in urban environments and could help alleviate food insecurity and related health problems. Therefore, trials were conducted in field rows and a green roof with seven varieties of sweet potatoes to determine whether 1) they differed in their production of greens and 2) harvesting greens influenced yield or nutrients of storage roots. There was no difference in the mass of sweet potatoes greens harvested among the varieties in either production system. Harvesting greens severely reduced the harvested mass of storage roots, although it increased the content of eight minerals in storage roots, including boron, calcium, copper, iron, phosphorous, potassium, sulfur, and zinc. Urban farmers may have to decide whether harvesting greens or storage roots are their primary objective if harvesting the former limits the latter. Future research should explore the timing of harvesting greens and the amount taken to see if different methods allow for a high yield of storage roots that are high in nutrients

Effects of Enhanced Coagulation and Ozonation on the Formation of Trihalomethanes and Haloacetic Acids Under Controlled Chlorination Conditions

Thi project evaluated the impact of enhanced coagulation and subsequent ozonation for the control of halogenated disinfection by-products (DBPs) in drinking water. Each of the nine raw waters sampled were chosen to represent a different element of the 3x3 Total Organic Carbon (TOC)/Alkalinity matrix established by the U.S. Environmental Protection Agency (USEPA). This matrix is part of the Stage 1 Disinfectants/Disinfection By-Products(D/DBP) Rule that requires specific percent reductions of TOC concentration based on the TOC and alkalinity of the raw water. The intention of the D/DBP Rule is to reduce public exposure to potentially harmful chemicals that form as a result of disinfecting water with chlorine. Each raw water was treated under enhanced coagulation conditions and then settled . A portion of the coagulated and settled water was then ozonated at a 1:1 O3 to TOC ratio by weight, at the pH resulting after coagulation. The three different fractions for each water utility (raw, coagulated, and post-ozonated water) were analyzed for pH, turbidity, TOC, dissolved oxygen carbon (DOC), ultraviolet absorbance at 254 nm (UV254), biodegradable DOC (BDOC) and 24-hour chlorine demand. Each fraction of water was then chlorinated under uniform formation conditions, quenched and analyzed for the four trihalomethanes (THMs) and all nine haloacetic acids (HAAs). The results show that enhanced coagulation removed the appropriate levels of TOC required by the USEPA, for all but one water sample. The percent removal of TOC increased with increasing raw water TOC concentration. The percent removals, as well as the trends, of UV254 absorbance were very similar to the percent removals of TOC. The results also showed that THM and HAA formation potentials were reduced in the coagulated waters in a similar manner as the reduction of UV254 absorbance and TOC concentration. When coagulation was followed by ozonation, the THM and HAA formation potentials decreased further. However, water samples that were ozonated before coagulation produced lower THM and HAA formation potentials than the post-ozonated samples. For waters with high bromide concentrations, the distribution of THM and HAA species favored the brominated compounds, when compared to waters with low bromide concentrations. TOC and UV254 absorbance were shown to be good indicators of THM and HAA formation potential, regardless of the treatment applied.Master of Science in Environmental Engineerin

Il contratto gratuito atipico e prassi negoziale

Con il presente lavoro si è cercato di chiarire la nozione giuridica di "gratuità", diversificandola tanto dall'onerosità, quanto dalla liberalità. Una volta chiarito il fondamento causale degli atti gratuiti (categoria che ricomprende i soli atti che, malgrado privi di corrispettivo, siano giustificati causalmente dal perseguimento di interessi economici) si è cercato di dare cittadinanza giuridica ai negozi gratuiti atipici ad effetto reale. Si è ritenuto opportuno soffermare l’attenzione sulla delicata questione relativa alla tradizionale propensione giurisprudenziale a negare che spostamenti giuridico-patrimoniali non possano trovare fondamento in fattispecie esulanti dall'alternativa contratto di scambio-negozio donativo e, per conseguenza, ad escludere o ridimensionare in modo drastico la possibile sfera di operatività di fattispecie gratuite non codificate. Infatti, pur essendo oramai pacifica la possibilità di concludere contratti atipici ad effetti reali, la giurisprudenza tende a negare che atti ad effetti reali possano trovare fondamento in fattispecie esulanti dall’alternativa contratto di scambio-negozio donativo e, per conseguenza, ad escludere o a comprimere fortemente l’area di operatività di fattispecie gratuite non codificate. Attraverso l'analisi di alcune diffuse prassi negoziali, del resto, si è rilevato la presenza di svariate ipotesi di spostamenti patrimoniali non onerosi ma non caratterizzati dallo spirito di liberalità ma da interessi economici. Si possono ricordare gli omaggi-premio, la diffusione gratuita di giornali o di campioni di prodotti, il trasferimento gratuito di calciatori. Minori perplessità hanno suscitato le stipulazioni gratuite afferenti ad obblighi di facere: tra queste si sono analizzate le lettere di patronage, il contratto di sponsorizzazione ed alcune offerte promozionali. Per quanto riguarda il contratto di sponsorizzazione, si è avuto modo di affrontare la natura della c.d. "sponsorizzazione interna", che obbliga lo sponsorizzato ad un pati: tale ipotesi pare non potersi qualificare gratuita, in quanto un simile obbligo non può non colorare la causa negoziale, tanto ciò vero che il suo inadempimento comporta la risoluzione del contratto e l'eventuale obbligo di risarcire i danni provocati allo sponsor

Programmable Sequence-Specific Transcriptional Regulation of Mammalian Genome Using Designer TAL Effectors

The ability to direct functional proteins to specific DNA sequences is a long-sought goal in the study and engineering of biological processes. Transcription activator–like effectors (TALEs) from Xanthomonas sp. are site-specific DNA-binding proteins that can be readily designed to target new sequences. Because TALEs contain a large number of repeat domains, it can be difficult to synthesize new variants. Here we describe a method that overcomes this problem. We leverage codon degeneracy and type IIs restriction enzymes to generate orthogonal ligation linkers between individual repeat monomers, thus allowing full-length, customized, repeat domains to be constructed by hierarchical ligation. We synthesized 17 TALEs that are customized to recognize specific DNA-binding sites, and demonstrate that they can specifically modulate transcription of endogenous genes (SOX2 and KLF4) in human cells.Harvard University. Society of FellowsNational Human Genome Research Institute (U.S.) (Center for Excellence in Genomics Science P50 HG003170)United States. Dept. of Energy (Genomes to Life DE-FG02-02ER63445)United States. Defense Advanced Research Projects Agency (W911NF-08-1-0254, G.M.C.)Wyss Institute of Biologically Inspired EngineeringNational Institutes of Health (U.S.) (Transformative R01 (R01 NS073124-01))European School of Molecular Medicine (predoctoral fellowship

Developmental Controls are Re-Expressed during Induction of Neurogenesis in the Neocortex of Young Adult Mice

Whether induction of low-level neurogenesis in normally non-neurogenic regions of the adult brain mimics aspects of developmental neurogenesis is currently unknown. Previously, we and others identified that biophysically induced, neuron subtype-specific apoptosis in mouse neocortex results in induction of neurogenesis of limited numbers of subtype-appropriate projection neurons with axonal projections to either thalamus or spinal cord, depending on the neuron subtype activated to undergo targeted apoptosis. Here, we test the hypothesis that developmental genes from embryonic corticogenesis are re-activated, and that some of these genes might underlie induction of low-level adult neocortical neurogenesis. We directly investigated this hypothesis via microarray analysis of microdissected regions of young adult mouse neocortex undergoing biophysically activated targeted apoptosis of neocortical callosal projection neurons. We compared the microarray results identifying differentially expressed genes with public databases of embryonic developmental genes. We find that, following activation of subtype-specific neuronal apoptosis, three distinct sets of normal developmental genes are selectively re-expressed in neocortical regions of induced neurogenesis in young adult mice: (1) genes expressed by subsets of progenitors and immature neurons in the developing ventricular and/or subventricular zones; (2) genes normally expressed by developmental radial glial progenitors; and (3) genes involved in synaptogenesis. Together with previous results, the data indicate that at least some developmental molecular controls over embryonic neurogenesis can be re-activated in the setting of induction of neurogenesis in the young adult neocortex, and suggest that some of these activate and initiate adult neuronal differentiation from endogenous progenitor populations. Understanding molecular mechanisms contributing to induced adult neurogenesis might enable directed CNS repair