Influence of preexercise muscle glycogen content on transcriptional activity of metabolic and myogenic genes in well-trained humans

To determine whether pre-exercise muscle glycogen content influences the transcription of several early-response genes involved in the regulation of muscle growth, seven male strength-trained subjects performed one-legged cycling exercise to exhaustion to lower muscle glycogen levels (Low) in one leg compared with the leg with normal muscle glycogen (Norm) and then the following day completed a unilateral bout of resistance training (RT). Muscle biopsies from both legs were taken at rest, immediately after RT, and after 3 h of recovery. Resting glycogen content was higher in the control leg (Norm leg) than in the Low leg (435 ± 87 vs. 193 ± 29 mmol/kg dry wt; P < 0.01). RT decreased glycogen content in both legs (P < 0.05), but postexercise values remained significantly higher in the Norm than the Low leg (312 ± 129 vs. 102 ± 34 mmol/kg dry wt; P < 0.01). GLUT4 (3-fold; P < 0.01) and glycogenin mRNA abundance (2.5-fold; not significant) were elevated at rest in the Norm leg, but such differences were abolished after exercise. Preexercise mRNA abundance of atrogenes was also higher in the Norm compared with the Low leg [atrogin: ?14-fold, P < 0.01; RING (really interesting novel gene) finger: ?3-fold, P < 0.05] but decreased for atrogin in Norm following RT (P < 0.05). There were no differences in the mRNA abundance of myogenic regulatory factors and IGF-I in the Norm compared with the Low leg. Our results demonstrate that 1) low muscle glycogen content has variable effects on the basal transcription of select metabolic and myogenic genes at rest, and 2) any differences in basal transcription are completely abolished after a single bout of heavy resistance training. We conclude that commencing resistance exercise with low muscle glycogen does not enhance the activity of genes implicated in promoting hypertrophy.

The activity of learning assistance

This paper uses cultural-historical activity to examine the nature of learning assistance, provided in university settings, to assist learners in coping with academic study. Alternative rival constructions of learning assistance, either as part of an overall university activity system, or as an activity system overlapping with other separate activity systems (e.g. library and faculty) within the university, are outlined. Data from a research study at one university are used to describe the object, tools and tensions in learning assistance; and, together with the history of the service, these are used to suggest that the current situation is one where the objects of the Learning Assistance Unit, the faculty and the library have separated from the object of a university.

Respiratory health effects of diesel particulate matter

Particulate matter (PM) emissions involve a complex mixture of solid and liquid particles suspended in a gas, where it is noted that PM emissions from diesel engines are a major contributor to the ambient air pollution problem. Whilst epidemiological studies have shown a link between increased ambient PM emissions and respiratory morbidity and mortality, studies of this design are not able to identify the PM constituents responsible for driving adverse respiratory health effects. This review explores in detail the physico-chemical properties of diesel particulate matter (DPM), and identifies the constituents of this pollution source that are responsible for the development of respiratory disease. In particular, this review shows that the DPM surface area and adsorbed organic compounds play a significant role in manifesting chemical and cellular processes that if sustained can lead to the development of adverse respiratory health effects. The mechanisms of injury involved included: inflammation, innate and acquired immunity, and oxidative stress. Understanding the mechanisms of lung injury from DPM will enhance efforts to protect at-risk individuals from the harmful respiratory effects of air pollutants.

Effect of a novel compound from Lycopodium obscurum L. on osteogenic activity of osteoblasts in vitro

We investigated the potential of an extract of Lycopodium obscurum L.; stigmastane-3-oxo-21-oic acid (SA), to enhance osteogensis of mouse osteoblastic MC3T3-E1 cells. SA at a concentration of 16 µM was found to have no significant effect upon the viability of the cells, thus concentrations of 8 µM and 16 µM of SA were used in all further experiments. Both concentrations of SA had an inhibitory affect upon alkaline phosphatase activity (ALP) after 8 days incubation, however, after 16 days activity was restored to control levels. However Alizarin red S staining showed increased levels of mineralization for both concentrations after 16 days culture. Real time PCR showed inhibition of genes Runx2 and Osterix genes responsible for the up-regulation of ALP. However early time point (8 days) up-regulation of bone matrix mineralization genes OPN and OCN, and late time point (16 days) up-regulation of both Jun-D and Fra-2 mRNA expression was significantly enhanced. These results suggest a potential me-chanism of SA in enhancing bone fracture healing is through the up-regulating bone matrix minera-lization.

Enhanced photocatalytic activity of titanium oxide nanotubes after heating treatment

Titanium oxide nanotubes were obtained by an electrochemical anodization method. Scanning electron microscope results demonstrate that the diameter of the tubes is about 120 nm and the length of the tubes is around 13 μm. Transmission electron microscope results indicate that the nanotubes are assembled by numerous nanoparticles and tube-like structure remains well after heat treatment at 400-600 °C. The photocatalysis performance of the nanotubes was evaluated in terms of the decomposition rate of methyl orange under UV irradiation. The results show that the photocatalytic activity was enhanced through the heating treatment of the nanotubes, and the nanotubes heated at 600 °C exhibits the best photocatalytic activity. X-ray diffraction patterns indicate that there is no phase transformation during the heat treatment. Therefore, the enhanced activity can be attributed to the improvement of nanotubes crystallinity, which may provide more insights about the effect of the crystallinity on the photocatalytic performance.

Isolation of bioactive compounds that relate to the anti-platelet activity of Cymbopogon ambiguus

Infusions and decoctions of Cymbopogon ambiguus have been used traditionally in Australia for the treatment of headache, chest infections and muscle cramps. The aim of the present study was to screen and identify bioactive compounds from C. ambiguus that could explain this plant's anti-headache activity. A dichloromethane extract of C. ambiguus was identified as having activity in adenosine-diphosphate-induced human platelet aggregation and serotonin-release inhibition bioassays. Subsequent fractionation of this extract led to the isolation of four phenylpropenoids, eugenol, elemicin, Eugenol methylether and trans-isoelemicin. While both Eugenol and elemicin exhibited dose-dependent inhibition of ADP-induced human platelet serotonin release, only eugenol displayed potent inhibitory activity with an IC(50) value of 46.6 microM, in comparison to aspirin, with an IC(50) value of 46.1 microM. These findings provide evidence to support the therapeutic efficacy of C. ambiguus in the non-conventional treatment of Headache and Inflammatory conditions.

PEGylation of lysine residues reduces the pro-migratory activity of IGF-I

Background: The insulin-like growth factor (IGF) system is composed of ligands and receptors which regulate cell proliferation, survival, differentiation and migration. Some functions are regulated via intracellular signaling cascades, others by involvement of the extracellular milieu, including binding proteins and other extracellular matrix proteins. However, understanding of their functions and the exact nature of these interactions remains incomplete. Methods: IGF-I was PEGylated at its lysine sites - K27, K65 and K68. Binding of PEG-IGF-I to the IGFBPs was analyzed using BIAcore and its ability to activate the IGF-IR was assessed using IGF-IR phosphorylation assay. Furthermore, functional consequences of PEGylating the lysine residues of IGF-I was investigated using cell viability and cell migration assays. In addition, particular downstream signaling pathways regularly implicated in these mechanisms were also dissected using phospho-AKT and phospho-ERK1/2 assays. Results: In this study, IGF-I specifically PEGylated at lysine 27 (PEG-K27), 65 (PEG-K65) or 68 (PEG-K68) were employed. Receptor phosphorylation was only reduced by 2-fold with PEG-K65 and PEG-K68 over all the time points tested, and as observed in two cell types, 3T3 fibroblasts and MCF-7 breast cancer cells. PEGylation at K27 resulted in a much larger effect, with more than 10-fold lower activation for 3T3 fibroblasts and a ~3 fold reduced IGF-IR activation for MCF-7 breast cancer cells over 15 minutes. In addition, all PEG-IGF-I variants demonstrated a ten-fold reduction in the association rate to IGF binding proteins (IGFBPs). Functionally, all PEG variants completely lost their ability to induce cell migration in the presence of IGFBP-3/vitronectin (VN) complexes as compared to IGF-I; in contrast, cell viability was fully preserved. Further investigations into the downstream signaling pathways revealed that the PI3-K/AKT pathway was preferentially affected upon treatment with the PEG-IGF-I variants compared to the MAPK/ERK pathway. Conclusion: PEGylation of IGF-I has an impact on cell migration but not cell viability. General significance: PEG-IGF-I may differentially modulate IGF-I mediated functions that are dependent on its interaction with its receptor as well as key extracellular proteins such as VN and IGFBPs.

Quantitative and qualitative changes in gene expression patterns characterize the activity of plaques in multiple sclerosis

Multiple sclerosis (MS) is a complex autoimmune disorder of the CNS with both genetic and environmental contributing factors. Clinical symptoms are broadly characterized by initial onset, and progressive debilitating neurological impairment. In this study, RNA from MS chronic active and MS acute lesions was extracted, and compared with patient matched normal white matter by fluorescent cDNA microarray hybridization analysis. This resulted in the identification of 139 genes that were differentially regulated in MS plaque tissue compared to normal tissue. Of these, 69 genes showed a common pattern of expression in the chronic active and acute plaque tissues investigated (Pvalue<0.0001, ρ=0.73, by Spearman's ρ analysis); while 70 transcripts were uniquely differentially expressed (≥1.5-fold) in either acute or chronic active tissues. These results included known markers of MS such as the myelin basic protein (MBP) and glutathione S-transferase (GST) M1, nerve growth factors, such as nerve injury-induced protein 1 (NINJ1), X-ray and excision DNA repair factors (XRCC9 and ERCC5) and X-linked genes such as the ribosomal protein, RPS4X. Primers were then designed for seven array-selected genes, including transferrin (TF), superoxide dismutase 1 (SOD1), glutathione peroxidase 1 (GPX1), GSTP1, crystallin, alpha-B (CRYAB), phosphomannomutase 1 (PMM1) and tubulin β-5 (TBB5), and real time quantitative (Q)-PCR analysis was performed. The results of comparative Q-PCR analysis correlated significantly with those obtained by array analysis (r=0.75, Pvalue<0.01, by Pearson's bivariate correlation). Both chronic active and acute plaques shared the majority of factors identified suggesting that quantitative, rather than gross qualitative differences in gene expression pattern may define the progression from acute to chronic active plaques in MS.

Identification of radiological alveolar pneumonia in children with high rates of hospitalized respiratory infections : Comparison of WHO-defined and pediatric pulmonologist diagnosis in the clinical context

Background A reliable standardized diagnosis of pneumonia in children has long been difficult to achieve. Clinical and radiological criteria have been developed by the World Health Organization (WHO), however, their generalizability to different populations is uncertain. We evaluated WHO defined chest radiograph (CXRs) confirmed alveolar pneumonia in the clinical context in Central Australian Aboriginal children, a high risk population, hospitalized with acute lower respiratory illness (ALRI). Methods CXRs in children (aged 1-60 months) hospitalized and treated with intravenous antibiotics for ALRI and enrolled in a randomized controlled trial (RCT) of Vitamin A/Zinc supplementation were matched with data collected during a population-based study of WHO-defined primary endpoint pneumonia (WHO-EPC). These CXRs were reread by a pediatric pulmonologist (PP) and classified as pneumonia-PP when alveolar changes were present. Sensitivities, specificities, positive and negative predictive values (PPV, NPV) for clinical presentations were compared between WHO-EPC and pneumonia-PP. Results Of the 147 episodes of hospitalized ALRI, WHO-EPC was significantly less commonly diagnosed in 40 (27.2%) compared to pneumonia-PP (difference 20.4%, 95% CI 9.6-31.2, P < 0.001). Clinical signs on admission were poor predictors for both pneumonia-PP and WHO-EPC; the sensitivities of clinical signs ranged from a high of 45% for tachypnea to 5% for fever + tachypnea + chest-indrawing. The PPV range was 40-20%, respectively. Higher PPVs were observed against the pediatric pulmonologist's diagnosis compared to WHO-EPC. Conclusions WHO-EPC underestimates alveolar consolidation in a clinical context. Its use in clinical practice or in research designed to inform clinical management in this population should be avoided. Pediatr Pulmonol. 2012; 47:386-392. (C) 2011 Wiley Periodicals, Inc.

Nedd4-2(NEDD4L) controls intracellular Na(+)-mediated activity of voltage-gated sodium channels in primary cortical neurons.

Nedd4-2, a HECT (homologous with E6-associated protein C-terminus)-type ubiquitin protein ligase, has been implicated in regulating several ion channels, including Navs (voltage-gated sodium channels). In Xenopus oocytes Nedd4-2 strongly inhibits the activity of multiple Navs. However, the conditions under which Nedd4-2 mediates native Nav regulation remain uncharacterized. Using Nedd4-2-deficient mice, we demonstrate in the present study that in foetal cortical neurons Nedd4-2 regulates Navs specifically in response to elevated intracellular Na(+), but does not affect steady-state Nav activity. In dorsal root ganglia neurons from the same mice, however, Nedd4-2 does not control Nav activities. The results of the present study provide the first physiological evidence for an essential function of Nedd4-2 in regulating Navs in the central nervous system.

Red colouration in apple fruit is due to the activity of the MYB transcription factor, MdMYB10

Anthocyanin concentration is an important determinant of the colour of many fruits. In apple (Malus x domestica), centuries of breeding have produced numerous varieties in which levels of anthocyanin pigment vary widely and change in response to environmental and developmental stimuli. The apple fruit cortex is usually colourless, although germplasm does exist where the cortex is highly pigmented due to the accumulation of either anthocyanins or carotenoids. From studies in a diverse array of plant species, it is apparent that anthocyanin biosynthesis is controlled at the level of transcription. Here we report the transcript levels of the anthocyanin biosynthetic genes in a red-fleshed apple compared with a white-fleshed cultivar. We also describe an apple MYB transcription factor, MdMYB10, that is similar in sequence to known anthocyanin regulators in other species. We further show that this transcription factor can induce anthocyanin accumulation in both heterologous and homologous systems, generating pigmented patches in transient assays in tobacco leaves and highly pigmented apple plants following stable transformation with constitutively expressed MdMYB10. Efficient induction of anthocyanin biosynthesis in transient assays by MdMYB10 was dependent on the co-expression of two distinct bHLH proteins from apple, MdbHLH3 and MdbHLH33. The strong correlation between the expression of MdMYB10 and apple anthocyanin levels during fruit development suggests that this transcription factor is responsible for controlling anthocyanin biosynthesis in apple fruit; in the red-fleshed cultivar and in the skin of other varieties, there is an induction of MdMYB10 expression concurrent with colour formation during development. Characterization of MdMYB10 has implications for the development of new varieties through classical breeding or a biotechnological approach.

Anti-proliferative and cytotoxic activity of pentadactylin isolated from Leptodactylus labyrinthicus on melanoma cells

Nowadays, the emergence of resistance to the current available chemotherapeutic drugs by cancer cells makes the development of new agents imperative. The skin secretion of amphibians is a natural rich source of antimicrobial peptides (AMP), and researchers have shown that some of these wide spectrum molecules are also toxic to cancer cells. The aim of this study was to verify a putative anticancer activity of the AMP pentadactylin isolated for the first time from the skin secretion of the frog Leptodactylus labyrinthicus and also to study its cytotoxic mechanism to the murine melanoma cell line B16F10. The results have shown that pentadactylin reduces the cell viability of B16F10 cells in a dose-dependent manner. It was also cytotoxic to normal human fibroblast cells; nevertheless, pentadactylin was more potent in the first case. The studies of action mechanism revealed that pentadactylin causes cell morphology alterations (e.g., round shape and shrinkage morphology), membrane disruption, DNA fragmentation, cell cycle arrest at the S phase, and alteration of mitochondrial membrane potential, suggesting that B16F10 cells die by apoptosis. The exact mechanism that causes reduction of cell viability and cytotoxicity after treatment with pentadactylin is still unknown. In conclusion, as cancer cells become resilient to death, it is worthwhile the discovery of new drugs such as pentadactylin that induces apoptosis.

Synthesis, characterization and activity of an immobilized photocatalyst : natural porous diatomite supported titania nanoparticles

Diatomite, a porous non-metal mineral, was used as support to prepare TiO2/diatomite composites by a modified sol–gel method. The as-prepared composites were calcined at temperatures ranging from 450 to 950 _C. The characterization tests included X-ray powder diffraction (XRD), scanning electron microscopy (SEM) with an energy-dispersive X-ray spectrometer (EDS), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption/desorption measurements. The XRD analysis indicated that the binary mixtures of anatase and rutile exist in the composites. The morphology analysis confirmed the TiO2 particles were uniformly immobilized on the surface of diatom with a strong interfacial anchoring strength, which leads to few drain of photocatalytic components during practical applications. In further XPS studies of hybrid catalyst, we found the evidence of the presence of Ti–O–Si bond and increased percentage of surface hydroxyl. In addition, the adsorption capacity and photocatalytic activity of synthesized TiO2/diatomite composites were evaluated by studying the degradation kinetics of aqueous Rhodamine B under UV-light irradiation. The photocatalytic degradation was found to follow pseudo-first order kinetics according to the Langmuir–Hinshelwood model. The preferable removal efficiency was observed in composites by 750 _C calcination, which is attributed to a relatively appropriate anatase/rutile mixing ratio of 90/10.

Electrocatalytic and SERS activity of Pt rich Pt-Pb nanostructures formed via the utilisation of in-situ underpotential deposition of lead

The controlled synthesis of nanostructured materials remains an ongoing area of research, especially as the size, shape and composition of nanomaterials can greatly influence their properties and applications. In this work we present the electrodeposition of highly dendritic platinum rich platinum-lead nanostructures, where lead acetate acts as an inorganic shape directing agent via underpotential deposition on the growing electrodeposit. It was found that these nanomaterials readily oxidise at potentials below monolayer oxide formation, which significantly impacts on the methanol electrooxidation reaction and correlates with the incipient hydrous oxide adatom mediator (IHOAM) model of electrocatalysis. Additionally these materials were tested for their surface enhanced Raman scattering (SERS) activity, where the high density of sharp tips provides promise for their application as SERS substrates.