Effect of Fetal Striatal and Astrocyte Transplants into Unilateral Excitotoxin-Lesioned Striatum

Studies have suggested that neurotrophic mechanisms may underlie transplant-induced functional recovery. Astrocytes have been reported to be a source of neurotrophic factors. The present study examined the possible role of cultured astrocytes in promoting recovery of apomorphine-induced rotation behavior in rats with unilateral kainic acid (KA) lesions of the striatum. Five weeks after the lesions, one group of rats received fetal striatal tissue (E17) transplants, another group received transplants of cultured astrocyte suspension, and the remaining rats received sham transplants and served as controls. Apomorphine-induced rotation behavior was tested 4 weeks after the KA lesions, and 5 and 10 weeks following the transplantation. The KA-induced rotation behavior was reduced by the striatal transplants but not by the cultured astrocyte transplants 5 and 10 weeks following the transplantation. Histochemicai analysis indicated that the striatal transplants had survived and grown and contained neurons and glia with similar morphology to those in the host brain. Immunocytochemical analysis of the astrocyte transplant sites revealed heavy glial fibrillary acidic protein and OX-42 staining in the transplant areas, suggesting that the transplanted astrocytes may have survived in the host brain. Although fetal striatal transplants can ameliorate apomorphine-induced rotation behavior, transplants of astrocytes alone may not be sufficient to reverse the functional deficits produced by KA lesions

Altered Forebrain and Hindbrain Development in Mice Mutant for theGsh-2Homeobox Gene

AbstractThe patterning of the mammalian brain is orchestrated by a large battery of regulatory genes. Here we examine the developmental function of theGsh-2nonclustered homeobox gene. Whole-mount and serial sectionin situhybridizations have been used to better defineGsh-2expression domains within the developing forebrain, midbrain, and hindbrain.Gsh-2transcripts are shown to be particularly abundant in the hindbrain and within the developing ganglionic eminences of the forebrain. In addition, mice carrying a targeted mutation ofGsh-2have been generated and characterized. Homozygous mutants uniformly failed to survive more than 1 day following birth. At the physiologic level the mutants experienced apnea and reduced levels of hemoglobin oxygenation. Histologically, the mutant brains had striking alterations of discrete components. In the forebrain the lateral ganglionic eminence was reduced in size. In the hindbrain, the area postrema, an important cardiorespiratory chemosensory center, was absent. The contiguous nucleus tractus solitarius, involved in integrating sensory input to maintain homeostasis, was also severely malformed in mutants. Immunohistochemistry was used to examine the mutant brains for alterations in the distribution of markers specific for serotonergic and cholinergic neurons. In addition,in situhybridizations were used to define expression patterns of the Dlx 2 and Nkx 2.1 homeobox genes in Gsh-2 mutant mice. The mutant lateral ganglionic eminences showed an abnormal absence of Dlx 2 expression. These results better define the genetic program of development of the mammalian brain, support neuromeric models of brain development, and further suggest similar patterning function for homeobox genes in phylogenetically diverse organisms

Maize Lethal Necrosis disease: review of molecular and genetic resistance mechanisms, socio-economic impacts, and mitigation strategies in sub-Saharan Africa

Background: Maize lethal necrosis (MLN) disease is a significant constraint for maize producers in sub-Saharan Africa (SSA). The disease decimates the maize crop, in some cases, causing total crop failure with far-reaching impacts on regional food security. Results: In this review, we analyze the impacts of MLN in Africa, finding that resource-poor farmers and consumers are the most vulnerable populations. We examine the molecular mechanism of MLN virus transmission, role of vectors and host plant resistance identifying a range of potential opportunities for genetic and phytosanitary interventions to control MLN. We discuss the likely exacerbating effects of climate change on the MLN menace and describe a sobering example of negative genetic association between tolerance to heat/drought and susceptibility to viral infection. We also review role of microRNAs in host plant response to MLN causing viruses as well as heat/drought stress that can be carefully engineered to develop resistant varieties using novel molecular techniques. Conclusions: With the dual drivers of increased crop loss due to MLN and increased demand of maize for food, the development and deployment of simple and safe technologies, like resistant cultivars developed through accelerated breeding or emerging gene editing technologies, will have substantial positive impact on livelihoods in the region. We have summarized the available genetic resources and identified a few large-effect QTLs that can be further exploited to accelerate conversion of existing farmer-preferred varieties into resistant cultivars

Redesigning crop varieties to win the race between climate change and food security

Climate change poses daunting challenges to agricultural production and food security. Rising temperatures, shifting weather patterns, and more frequent extreme events have already demonstrated their effects on local, regional, and global agricultural systems. Crop varieties that withstand climate-related stresses and are suitable for cultivation in innovative cropping systems will be crucial to maximize risk avoidance, productivity, and profitability under climate-changed environments. We surveyed 588 expert stakeholders to predict current and novel traits that may be essential for future pearl millet, sorghum, maize, groundnut, cowpea, and common bean varieties, particularly in sub-Saharan Africa. We then review the current progress and prospects for breeding three prioritized future-essential traits for each of these crops. Experts predict that most current breeding priorities will remain important, but that rates of genetic gain must increase to keep pace with climate challenges and consumer demands. Importantly, the predicted future-essential traits include innovative breeding targets that must also be prioritized; for example, (1) optimized rhizosphere microbiome, with benefits for P, N, and water use efficiency, (2) optimized performance across or in specific cropping systems, (3) lower nighttime respiration, (4) improved stover quality, and (5) increased early vigor. We further discuss cutting-edge tools and approaches to discover, validate, and incorporate novel genetic diversity from exotic germplasm into breeding populations with unprecedented precision, accuracy, and speed. We conclude that the greatest challenge to developing crop varieties to win the race between climate change and food security might be our innovativeness in defining and boldness to breed for the traits of tomorrow

Spatiotemporal distribution of the insulin-like growth factor receptor in the rat olfactory bulb.

Insulin-like growth factor I (IGF-I) and its receptor (IGF-IR) are involved in growth of neurons. In the rat olfactory epithelium, we previously showed IGF-IR immunostaining in subsets of olfactory receptor neurons. We now report that IGF-IR staining was heaviest in the olfactory nerve layer of the rat olfactory bulb at embryonic days 18, and 19 and postnatal day 1, with labeling of protoglomeruli. In the adult, only a few glomeruli were IGF-IR-positive, some of which were unusually small and strongly labeled. Some IGF-IR-positive fibers penetrated deeper into the external plexiform layer, even in adults. In developing tissues, IGF-IR staining co-localized with that for olfactory marker protein and growth associated protein GAP-43, but to a lesser extent with synaptophysin. In the adult, IGF-IR-positive fibers were compartmentalized within glomeruli. IGF-I may play a role in glomerular synaptogenesis and/or plasticity, possibly contributing to development of coding patterns for odor detection or identification.Fil: Ferrari, Carina Cintia. University Of Cincinnati; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Johnson, Brett A.. University of California at Irvine; Estados UnidosFil: Leon, Michael. University of California at Irvine; Estados UnidosFil: Pixley, Sarah K.. University of Cincinnati; Estados Unido

Polymer Coating of Carbon Nanotube Fibers for Electric Microcables

Carbon nanotubes (CNTs) are considered the most promising candidates to replace Cu and Al in a large number of electrical, mechanical and thermal applications. Although most CNT industrial applications require macro and micro size CNT fiber assemblies, several techniques to make conducting CNT fibers, threads, yarns and ropes have been reported to this day, and improvement of their electrical and mechanical conductivity continues. Some electrical applications of these CNT conducting fibers require an insulating layer for electrical insulation and protection against mechanical tearing. Ideally, a flexible insulator such as hydrogenated nitrile butadiene rubber (HNBR) on the CNT fiber can allow fabrication of CNT coils that can be assembled into lightweight, corrosion resistant electrical motors and transformers. HNBR is a largely used commercial polymer that unlike other cable-coating polymers such as polyvinyl chloride (PVC), it provides unique continuous and uniform coating on the CNT fibers. The polymer coated/insulated CNT fibers have a 26.54 μm average diameter—which is approximately four times the diameter of a red blood cell—is produced by a simple dip-coating process. Our results confirm that HNBR in solution creates a few microns uniform insulation and mechanical protection over a CNT fiber that is used as the electrically conducting core

Fabrication and characterization of a multiwall carbon nanotube needle biosensor

A nanotube electronic needle biosensor was developed to provide fast, low cost, accurate detection of biomolecules. The sensor was formed by synthesizing highly aligned multi-wall carbon nanotube arrays. Nanotube bundles from the array were welded onto the tips of tungsten needles using a microscope. The needles were then encased in glass and a polymer coating. Cyclic voltammetry (CV) for the respective reduction of 6 mM K3Fe(CN)6in a 1.0 M KNO3was performed to examine the redox behavior of the nanotube needle. The CV results showed a steady-state response attributable to radial diffusion with a high steady-state current density. An amperometric sensor was then developed for glucose detection by physical attachment of glucose oxidase on the nanotube needle. A label-free immunosensor based on electrochemical impedance spectroscopy was also formed. The nanotube needle amperometric have good sensitivity with a low detection limit, and the possibility exists to keep decreasing the size of the needle to increase the sensitivity.4 page(s

A Carbon nanotube needle biosensor

A carbon nanotube needle biosensor was developed to provide fast, cost effective and highly sensitive electrochemical detection of biomolecules. The sensor was fabricated based on an array of aligned multi-wall carbon nanotubes synthesized by chemical vapor deposition. A bundle of nanotubes in the array was welded onto the tip of a tungsten needle under a microscope. The needle was then encased in glass and a polymer coating leaving only the tip of the needle exposed. Cyclic voltammetry was performed to examine the redox behavior of the nanotube needle. The cyclic voltammetry results showed a steady-state response attributable to radial diffusion with a high steady-state current density. An amperometric sensor was then developed for glucose detection by physically attaching glucose oxidase on the nanotube needle. The amperometric response of these nanotube needles showed a high sensitivity with a low detection limit. It is expected that the nanotube needle can be sharpened to increase the sensitivity to the point where the current is almost too small to measure. The simple manufacturing method should allow commodity level production of highly sensitive electronic biosensors.8 page(s

A nanotube array immunosensor for direct electrochemical detection of antigen-antibody binding

This paper describes the development of a label-free immunosensor based on carbon nanotube (CNT) array electrodes. Highly aligned multi-walled carbon nanotubes were grown on a Fe/Al2O3/SiO2/Si substrate by chemical vapor deposition (CVD). The substrate was patterned with 100 μm square blocks and 100 μm spacing between blocks. Carbon nanotube towers up to 2 mm in height grew from the blocks, and the towers were easy to peel off the silicon substrate. The harvested towers were cast in epoxy and both ends were polished; one end for electrical connection, and the other end for use as an electrode. The nanotube electrode was then electrochemically activated to open the nanotube ends and to expose COOH groups on the surface. Anti-mouse IgG was then covalently immobilized on the nanotube array. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterise the binding of mouse IgG to its specific antibody already immobilized on the nanotube electrode surface. A non-linear calibration plot was constructed based on the change in the electron transfer resistance at the electrode surface as a function of mouse IgG concentrations. A detection limit of 200 ng/mL and a dynamic range up to a 100 μg/mL range were obtained. Overall, it was found that the nanotube array immunosensor was easy to fabricate and has good sensitivity.6 page(s