Laser composite surfacing of a magnesium alloy with chromium carbide

The present study concerns improving the wear resistance of a Mg alloy (MEZ) by melting the surface with a high power laser and simultaneously injecting hard particles, of Cr2C3 +(25mm -40mm) into the surface. The laser processing was carried out using a continuous wave CO2 laser, Model: Rofin Sinar, RS 10000, with a beam diameter of 4 mm and a focal point 30 mm above the surface. Following laser processing, a detailed investigation of the microstructures, compositions and phases were undertaken and mechanical (wear resistance) and electrochemical (pitting corrosion resistance) properties of the surface layer were evaluated in details. The microstructure of the surface layer consists of uniformly dispersed Cr2C3 precipitates in grain-refined matrix. The micro-hardness and wear resistance of the surface layer were significantly improved as compared to the base metal

Identification of Novel Pro-Migratory, Cancer-Associated Genes Using Quantitative, Microscopy-Based Screening

Background: Cell migration is a highly complex process, regulated by multiple genes, signaling pathways and external stimuli. To discover genes or pharmacological agents that can modulate the migratory activity of cells, screening strategies that enable the monitoring of diverse migratory parameters in a large number of samples are necessary. Methodology: In the present study, we describe the development of a quantitative, high-throughput cell migration assay, based on a modified phagokinetic tracks (PKT) procedure, and apply it for identifying novel pro-migratory genes in a cancer-related gene library. In brief, cells are seeded on fibronectin-coated 96-well plates, covered with a monolayer of carboxylated latex beads. Motile cells clear the beads, located along their migratory paths, forming tracks that are visualized using an automated, transmitted-light screening microscope. The tracks are then segmented and characterized by multi-parametric, morphometric analysis, resolving a variety of morphological and kinetic features. Conclusions: In this screen we identified 4 novel genes derived from breast carcinoma related cDNA library, whose over-expression induces major alteration in the migration of the stationary MCF7 cells. This approach can serve for high throughput screening for novel ways to modulate cellular migration in pathological states such as tumor metastasis and invasion

A Plant-Derived Recombinant Human Glucocerebrosidase Enzyme—A Preclinical and Phase I Investigation

Gaucher disease is a progressive lysosomal storage disorder caused by the deficiency of glucocerebrosidase leading to the dysfunction in multiple organ systems. Intravenous enzyme replacement is the accepted standard of treatment. In the current report, we evaluate the safety and pharmacokinetics of a novel human recombinant glucocerebrosidase enzyme expressed in transformed plant cells (prGCD), administered to primates and human subjects. Short term (28 days) and long term (9 months) repeated injections with a standard dose of 60 Units/kg and a high dose of 300 Units/kg were administered to monkeys (n = 4/sex/dose). Neither clinical drug-related adverse effects nor neutralizing antibodies were detected in the animals. In a phase I clinical trial, six healthy volunteers were treated by intravenous infusions with escalating single doses of prGCD. Doses of up to 60 Units/kg were administered at weekly intervals. prGCD infusions were very well tolerated. Anti-prGCD antibodies were not detected. The pharmacokinetic profile of the prGCD revealed a prolonged half-life compared to imiglucerase, the commercial enzyme that is manufactured in a costly mammalian cell system. These studies demonstrate the safety and lack of immunogenicity of prGCD. Following these encouraging results, a pivotal phase III clinical trial for prGCD was FDA approved and is currently ongoing.ClinicalTrials.gov NCT00258778

Virus-Induced Gene Silencing as a Tool for Comparative Functional Studies in Thalictrum

Perennial woodland herbs in the genus Thalictrum exhibit high diversity of floral morphology, including four breeding and two pollination systems. Their phylogenetic position, in the early-diverging eudicots, makes them especially suitable for exploring the evolution of floral traits and the fate of gene paralogs that may have shaped the radiation of the eudicots. A current limitation in evolution of plant development studies is the lack of genetic tools for conducting functional assays in key taxa spanning the angiosperm phylogeny. We first show that virus-induced gene silencing (VIGS) of a PHYTOENE DESATURASE ortholog (TdPDS) can be achieved in Thalictrum dioicum with an efficiency of 42% and a survival rate of 97%, using tobacco rattle virus (TRV) vectors. The photobleached leaf phenotype of silenced plants significantly correlates with the down-regulation of endogenous TdPDS (P<0.05), as compared to controls. Floral silencing of PDS was achieved in the faster flowering spring ephemeral T. thalictroides. In its close relative, T. clavatum, silencing of the floral MADS box gene AGAMOUS (AG) resulted in strong homeotic conversions of floral organs. In conclusion, we set forth our optimized protocol for VIGS by vacuum-infiltration of Thalictrum seedlings or dormant tubers as a reference for the research community. The three species reported here span the range of floral morphologies and pollination syndromes present in Thalictrum. The evidence presented on floral silencing of orthologs of the marker gene PDS and the floral homeotic gene AG will enable a comparative approach to the study of the evolution of flower development in this group

LKR/SDH Plays Important Roles throughout the Tick Life Cycle Including a Long Starvation Period

BACKGROUND:Lysine-ketoglutarate reductase/saccharopine dehydrogenase (LKR/SDH) is a bifunctional enzyme catalyzing the first two steps of lysine catabolism in plants and mammals. However, to date, the properties of the lysine degradation pathway and biological functions of LKR/SDH have been very little described in arthropods such as ticks. METHODOLOGY/PRINCIPAL FINDINGS:We isolated and characterized the gene encoding lysine-ketoglutarate reductase (LKR, EC 1.5.1.8) and saccharopine dehydrogenase (SDH, EC 1.5.1.9) from a tick, Haemaphysalis longicornis, cDNA library that encodes a bifunctional polypeptide bearing domains similar to the plant and mammalian LKR/SDH enzymes. Expression of LKR/SDH was detected in all developmental stages, indicating an important role throughout the tick life cycle, including a long period of starvation after detachment from the host. The LKR/SDH mRNA transcripts were more abundant in unfed and starved ticks than in fed and engorged ticks, suggesting that tick LKR/SDH are important for the starved tick. Gene silencing of LKR/SDH by RNAi indicated that the tick LKR/SDH plays an integral role in the osmotic regulation of water balance and development of eggs in ovary of engorged females. CONCLUSIONS/SIGNIFICANCE:Transcription analysis and gene silencing of LKR/SDH indicated that tick LKR/SDH enzyme plays not only important roles in egg production, reproduction and development of the tick, but also in carbon, nitrogen and water balance, crucial physiological processes for the survival of ticks. This is the first report on the role of LKR/SDH in osmotic regulation in animals including vertebrate and arthropods

Gene Transfer to Chicks Using Lentiviral Vectors Administered via the Embryonic Chorioallantoic Membrane

The lack of affordable techniques for gene transfer in birds has inhibited the advancement of molecular studies in avian species. Here we demonstrate a new approach for introducing genes into chicken somatic tissues by administration of a lentiviral vector, derived from the feline immunodeficiency virus (FIV), into the chorioallantoic membrane (CAM) of chick embryos on embryonic day 11. The FIV-derived vectors carried yellow fluorescent protein (YFP) or recombinant alpha-melanocyte-stimulating hormone (α-MSH) genes, driven by the cytomegalovirus (CMV) promoter. Transgene expression, detected in chicks 2 days after hatch by quantitative real-time PCR, was mostly observed in the liver and spleen. Lower expression levels were also detected in the brain, kidney, heart and breast muscle. Immunofluorescence and flow cytometry analyses confirmed transgene expression in chick tissues at the protein level, demonstrating a transduction efficiency of ∼0.46% of liver cells. Integration of the viral vector into the chicken genome was demonstrated using genomic repetitive (CR1)-PCR amplification. Viability and stability of the transduced cells was confirmed using terminal deoxynucleotidyl transferase (dUTP) nick end labeling (TUNEL) assay, immunostaining with anti-proliferating cell nuclear antigen (anti-PCNA), and detection of transgene expression 51 days post transduction. Our approach led to only 9% drop in hatching efficiency compared to non-injected embryos, and all of the hatched chicks expressed the transgenes. We suggest that the transduction efficiency of FIV vectors combined with the accessibility of the CAM vasculature as a delivery route comprise a new powerful and practical approach for gene delivery into somatic tissues of chickens. Most relevant is the efficient transduction of the liver, which specializes in the production and secretion of proteins, thereby providing an optimal target for prolonged study of secreted hormones and peptides

Early and reversible changes to the hippocampal proteome in mice on a high-fat diet

Funding LMW, FMC, CG, ACM and C-DM were funded by the Scottish Government’s Rural and Environment Science and Analytical Services Division (RESAS). FHM was supported by an EASTBIO DTP BBSRC studentship. DS was supported by a SULSA studentship.Peer reviewedPublisher PD

Comprehensive Gene and microRNA Expression Profiling Reveals a Role for microRNAs in Human Liver Development

BACKGROUND AND AIMS: microRNAs (miRNAs) are small noncoding RNAs that regulate cognate mRNAs post-transcriptionally. miRNAs have been implicated in regulating gene expression in embryonic developmental processes, including proliferation and differentiation. The liver is a multifunctional organ, which undergoes rapid changes during the developmental period and relies on tightly-regulated gene expression. Little is known regarding the complex expression patterns of both mRNAs and miRNAs during the early stages of human liver development, and the role of miRNAs in the regulation of this process has not been studied. The aim of this work was to study the impact of miRNAs on gene expression during early human liver development. METHODS: Global gene and miRNA expression were profiled in adult and in 9-12w human embryonic livers, using high-density microarrays and quantitative RT-PCR. RESULTS: Embryonic liver samples exhibited a gene expression profile that differentiated upon progression in the developmental process, and revealed multiple regulated genes. miRNA expression profiling revealed four major expression patterns that correlated with the known function of regulated miRNAs. Comparison of the expression of the most regulated miRNAs to that of their putative targets using a novel algorithm revealed a significant anti-correlation for several miRNAs, and identified the most active miRNAs in embryonic and in adult liver. Furthermore, our algorithm facilitated the identification of TGFbeta-R1 as a novel target gene of let-7. CONCLUSIONS: Our results uncover multiple regulated miRNAs and genes throughout human liver development, and our algorithm assists in identification of novel miRNA targets with potential roles in liver development