A New Approach in the Use of Multimedia for Technology Enhanced Learning.

In this paper we describe ongoing work in the Electrical and Computer Engineering Department at the University of Florida as we offer an Online MS degree in Electrical Engineering and as we proceed with the development of major components of a BS degree in Electrical Engineering. In particular we describe the implementation of the "lectures on demand" method using multimedia streaming technologies within the now widely accepted Asynchronous Learning Network (ALN) model. Each class in the program is delivered on campus via the traditional face to face lecture mode. However, the classes make explicit use of computer and communication technology to facilitate an asynchronous mode of learning for both on-campus as well as distance education students. The lecture and in class interactions including computer demonstrations are captured as video or computer animations. This digital video is compressed and broadcast 'live' via the Internet so that students who cannot attend the class can join the lecture. After the class, a student assistant is engaged to generate high quality image and graphical copy of material developed spontaneously in the class by the Instructor. These are then integrated with class notes into a synchronized multimedia presentation

Skeletal muscle atrophy in sedentary Zucker obese rats is not caused by calpain-mediated muscle damage or lipid peroxidation induced by oxidative stress.

BACKGROUND: Skeletal muscle undergoes significant atrophy in Type 2 diabetic patients and animal models. We aimed to determine if atrophy of Zucker rat skeletal muscle was due to the activation of intracellular damage pathways induced by excess reactive oxygen species production (specifically those associated with the peroxidation of lipid membranes) and calpain activity. 14 week old obese Zucker rats and littermate lean controls were injected with 1% Evan’s Blue Dye. Animals were anaesthetised and extensor digitorum longus and soleus muscles were dissected, snap frozen and analysed for ROS-mediated F(2)-isoprostane production and calpain activation/autolysis. Contralateral muscles were histologically analysed for markers of muscle membrane permeability and atrophy. RESULTS: Muscle mass was lower in extensor digitorum longus and soleus of obese compared with lean animals, concomitant with reduced fibre area. Muscles from obese rats had a higher proportional area of Evan’s Blue Dye fluorescence, albeit this was localised to the interstitium/external sarcolemma. There were no differences in F(2)-isoprostane production when expressed relative to arachidonic acid content, which was lower in the obese EDL and soleus muscles. There were no differences in the activation of either μ-calpain or calpain-3. CONCLUSIONS: This study highlights that atrophy of Zucker rat skeletal muscle is not related to sarcolemmal damage, sustained hyperactivation of the calpain proteases or excessive lipid peroxidation. As such, establishing the correct pathways involved in atrophy is highly important so as to develop more specific treatment options that target the underlying cause. This study has eliminated two of the potential pathways theorised to be responsible

A novel expression system of domain I of human beta2 glycoprotein I in Escherichia coli

BACKGROUND: The antiphospholipid syndrome (APS), characterised by recurrent miscarriage and thrombosis, is a significant cause of morbidity and mortality. Domain I (DI) of human beta 2 glycoprotein I (β(2)GPI) is thought to contain crucial antibody binding epitopes for antiphospholipid antibodies (aPL), which are critical to the pathogenesis of APS. Expressing this protein in bacteria could facilitate studies investigating how this molecule interacts with aPL. METHODS: Using a computer programme called Juniper, sequentially overlapping primers were designed to be used in a recursive polymerase chain reaction (PCR) to produce a synthetic DI gene. Specifically Juniper incorporates 'major' codons preferred by bacteria altering 41 codons out of 61. This was cloned into the expression plasmid pET(26b) and expressed in BL21(DE3) Escherichia coli (E. coli). By virtue of a pelB leader sequence, periplasmic localisation of DI aided disulphide bond formation and toxicity was addressed by tightly regulating expression through the high stringency T7lac promoter. RESULTS: Purified, soluble his-tagged DI in yields of 750 μg/L bacterial culture was obtained and confirmed on Western blot. Expression using the native human cDNA sequence of DI in the same construct under identical conditions yielded significantly less DI compared to the recombinant optimised sequence. This constitutes the first description of prokaryotic expression of soluble DI of β(2)GPI. Binding to murine monoclonal antibodies that recognise conformationally restricted epitopes on the surface of DI and pathogenic human monoclonal IgG aPL was confirmed by direct and indirect immunoassay. Recombinant DI also bound a series of 21 polyclonal IgG samples derived from patients with APS. CONCLUSION: By producing a synthetic gene globally optimised for expression in E. coli, tightly regulating expression and utilising periplasmic product translocation, efficient, soluble E. coli expression of the eukaryotic protein DI of β(2)GPI is possible. This novel platform of expression utilising pan-gene prokaryote codon optimisation for DI production will aid future antigenic studies. Furthermore if DI or peptide derivatives of DI are eventually used in the therapeutic setting either as toleragen or as a competitive inhibitor of pathogenic aPL, then an E. coli production system may aid cost-effective production

Tissue expression of PD-L1 mediates peripheral T cell tolerance

Programmed death 1 (PD-1), an inhibitory receptor expressed on activated lymphocytes, regulates tolerance and autoimmunity. PD-1 has two ligands: PD-1 ligand 1 (PD-L1), which is expressed broadly on hematopoietic and parenchymal cells, including pancreatic islet cells; and PD-L2, which is restricted to macrophages and dendritic cells. To investigate whether PD-L1 and PD-L2 have synergistic or unique roles in regulating T cell activation and tolerance, we generated mice lacking PD-L1 and PD-L2 (PD-L1/PD-L2−/− mice) and compared them to mice lacking either PD-L. PD-L1 and PD-L2 have overlapping functions in inhibiting interleukin-2 and interferon-γ production during T cell activation. However, PD-L1 has a unique and critical role in controlling self-reactive T cells in the pancreas. Our studies with bone marrow chimeras demonstrate that PD-L1/PD-L2 expression only on antigen-presenting cells is insufficient to prevent the early onset diabetes that develops in PD-L1/PD-L2−/− non-obese diabetic mice. PD-L1 expression in islets protects against immunopathology after transplantation of syngeneic islets into diabetic recipients. PD-L1 inhibits pathogenic self-reactive CD4+ T cell–mediated tissue destruction and effector cytokine production. These data provide evidence that PD-L1 expression on parenchymal cells rather than hematopoietic cells protects against autoimmune diabetes and point to a novel role for PD-1–PD-L1 interactions in mediating tissue tolerance

Protective Role of Programmed Death 1 Ligand 1 (PD-L1)in Nonobese Diabetic Mice : The Paradox in Transgenic Models

OBJECTIVE—Coinhibitory signals mediated via programmed death 1 (PD-1) receptor play a critical role in downregulating immune responses and in maintaining peripheral tolerance. Programmed death 1 ligand 1 (PD-L1), the interacting ligand for PD-1, widely expressed in many cell types, acts as a tissue-specific negative regulator of pathogenic T-cell responses. We investigated the protective potential of PD-L1 on autoimmune diabetes by transgenically overexpressing PD-L1 in pancreatic β-cells in nonobese diabetic (NOD) mice

The Escherichia coli transcriptome mostly consists of independently regulated modules

Underlying cellular responses is a transcriptional regulatory network (TRN) that modulates gene expression. A useful description of the TRN would decompose the transcriptome into targeted effects of individual transcriptional regulators. Here, we apply unsupervised machine learning to a diverse compendium of over 250 high-quality Escherichia coli RNA-seq datasets to identify 92 statistically independent signals that modulate the expression of specific gene sets. We show that 61 of these transcriptomic signals represent the effects of currently characterized transcriptional regulators. Condition-specific activation of signals is validated by exposure of E. coli to new environmental conditions. The resulting decomposition of the transcriptome provides: a mechanistic, systems-level, network-based explanation of responses to environmental and genetic perturbations; a guide to gene and regulator function discovery; and a basis for characterizing transcriptomic differences in multiple strains. Taken together, our results show that signal summation describes the composition of a model prokaryotic transcriptome

A highly selective, label-free, homogenous luminescent switch-on probe for the detection of nanomolar transcription factor NF-kappaB

Transcription factors are involved in a number of important cellular processes. The transcription factor NF-κB has been linked with a number of cancers, autoimmune and inflammatory diseases. As a result, monitoring transcription factors potentially represents a means for the early detection and prevention of diseases. Most methods for transcription factor detection tend to be tedious and laborious and involve complicated sample preparation, and are not practical for routine detection. We describe herein the first label-free luminescence switch-on detection method for transcription factor activity using Exonuclease III and a luminescent ruthenium complex, [Ru(phen)2(dppz)]2+. As a proof of concept for this novel assay, we have designed a double-stranded DNA sequence bearing two NF-κB binding sites. The results show that the luminescence response was proportional to the concentration of the NF-κB subunit p50 present in the sample within a wide concentration range, with a nanomolar detection limit. In the presence of a known NF-κB inhibitor, oridonin, a reduction in the luminescence response of the ruthenium complex was observed. The reduced luminescence response of the ruthenium complex in the presence of small molecule inhibitors allows the assay to be applied to the high-throughput screening of chemical libraries to identify new antagonists of transcription factor DNA binding activity. This will allow the rapid and low cost identification and development of novel scaffolds for the treatment of diseases caused by the deregulation of transcription factor activity

Differentiation dependent expression of urocortin’s mRNA and peptide in human osteoprogenitor cells: influence of BMP-2, TGF-beta-1 and dexamethasone

Urocortin-1 (UCN) a corticotropin releasing-factor (CRF) related peptide, has been found to be expressed in many different tissues like the central nervous system, the cardiovascular system, adipose tissue, and skeletal muscle. The effects of UCN are mediated via stimulation of CRF-receptors 1 and 2 (CRFR1 and 2, CRFR’s) with a high affinity for CRFR2. It has been shown that the CRF-related peptides and CRFR’s are involved in the regulation of stress-related endocrine, autonomic and behavioural responses. Using immunocytochemistry, immunohistochemistry and RT–PCR, we now can show the differentiation dependent expression of UCN mRNA and peptide in human mesenchymal progenitor cells (MSCs) directed to the osteoblastic phenotype for the first time. UCN expression was down regulated by TGF-beta and BMP-2 in the early proliferation phase of osteoblast development, whereas dexamethasone (dex) minimally induced UCN gene expression during matrix maturation after 24 h stimulation. Stimulation of MSCs for 28 days with ascorbate/beta-glycerophosphate (asc/bGp) induced UCN gene expression at day 14. This effect was prevented when using 1,25-vitamin D3 or dex in addition. There was no obvious correlation to osteocalcin (OCN) gene expression in these experiments. In MSCs from patients with metabolic bone disease (n = 9) UCN gene expression was significantly higher compared to MSCs from normal controls (n = 6). Human MSCs did not express any of the CRFR’s during differentiation to osteoblasts. Our results indicate that UCN is produced during the development of MSCs to osteoblasts and differentially regulated during culture as well as by differentiation factors. The expression is maximal between proliferation and matrix maturation phase. However, UCN does not seem to act on the osteoblast itself as shown by the missing CRFR’s. Our results suggest new perspectives on the role of urocortin in human skeletal tissue in health and disease