Contribution of Azolla filiculoides to hydrazine elimination from water

Wetlands Ecology and Management - In this research we report the significant effect of the floating water fern Azolla filiculoides on the elimination of hydrazine (N2H4) from water, which is a...     

Proliferation and differentiation potential of cryopreserved human skin-derived precursors

Objectives: Skin‐derived precursors are recognized to be a potentially autologous and accessible source of neural precursor cells for drug screening or cell‐based treatments, in many neurological disorders. Thus, it is necessary to investigate appropriate methods for cryopreservation of such human skin‐derived precursors (hSKPs). The aim of this study was to evaluate different cryopreservation techniques for retention of hSKPs to discover an optimized protocol. Materials and methods: We cryopreserved hSKPs treated with 0%, 10%, 20%, 30% and 40% foetal bovine serum (FBS) and three concentrations of dimethylsulphoxide (DMSO) 5%, 10% and 15%, with two different storage periods in liquid nitrogen (2 days: short‐term storage; and 2 months: long‐term storage). Then, we assessed survival and proliferation levels of the cells after freeze–thaw processes, by viability measurement and colony‐forming assay. For detecting hSKPs, we used immunocytochemistry and RT‐PCR assessments. Results: Our findings indicated that hSKPs cryopreserved in 5% DMSO without FBS, had better survival and proliferation potentials compared to other working formulations. With various concentrations of cryoprotectants over different time periods, hSKPs retained their differentiation potentiality and were able to differentiate into neurons (NFM and βΙΙΙ tubulin‐positive), glial cells (GFAP‐positive) and smooth muscle cells (SMA‐positive). Conclusions: Results revealed that in only 5% DMSO, hSKPs could be cryopreserved for long‐term storage with considerable survival and proliferation levels, without losing multipotency.     

Pokeweed antiviral protein increases HIV-1 particle infectivity by activating the cellular mitogen activated protein kinase pathway

Pokeweed antiviral protein (PAP) is a plant-derived N-glycosidase that exhibits antiviral activity against several viruses. The enzyme removes purine bases from the messenger RNAs of the retroviruses Human immunodeficiency virus-1 and Human T-cell leukemia virus-1. This depurination reduces viral protein synthesis by stalling elongating ribosomes at nucleotides with a missing base. Here, we transiently expressed PAP in cells with a proviral clone of HIV-1 to examine the effect of the protein on virus production and quality. PAP reduced virus production by approximately 450-fold, as measured by p24 ELISA of media containing virions, which correlated with a substantial decline in virus protein synthesis in cells. However, particles released from PAP-expressing cells were approximately 7-fold more infectious, as determined by single-cycle infection of 1G5 cells and productive infection of MT2 cells. This increase in infectivity was not likely due to changes in the processing of HIV-1 polyproteins, RNA packaging efficiency or maturation of virus. Rather, expression of PAP activated the ERK1/2 MAPK pathway to a limited extent, resulting in increased phosphorylation of viral p17 matrix protein. The increase in infectivity of HIV-1 particles produced from PAP-expressing cells was compensated by the reduction in virus number; that is, virus production decreased upon de novo infection of cells over time. However, our findings emphasize the importance of investigating the influence of heterologous protein expression upon host cells when assessing their potential for antiviral applications.     

Production and Evaluation of Toxoplasma gondii Recombinant GRA7 for Serodiagnosis of Human Infections

The precise diagnosis of the acute toxoplasmosis in pregnant women and immunocompromsied patients has critical importance. Most of the commercially available assays use the whole Toxoplasma soluble extract as the antigen. However, the assays currently available for the detection of specific anti-Toxoplasma antibodies may vary in their abilities to detect serum immunoglobulins, due to the lack of a purified standardized antigen. The aim of this study was production and evaluation of the usefulness of the recombinant Toxoplasma gondii GRA7 antigen for the serodiagnosis of Toxoplasma gondii IgM and IgG by ELISA. A total of 70 T. gondii IgM positive sera, 74 T. gondii IgG positive sera, and 60 sera from subjects who were not infected with T. gondii were examined. These sera were shown different absorbance values in ELISA test. To control the specificity of the rGRA7 other parasitic diseases, for example, echinococcosis, malaria, leishmaniasis, fascioliasis, and strongyloidiasis were tested of which none showed positive results. Sensitivity and specificity of the generated recombinant IgG ELISA in comparison with commercial ELISA (com ELISA) were 89% and 90%, and the sensitivity and specificity of the generated recombinant IgM ELISA were 96% and 90%, respectively. The results obtained here show that this antigen is useful for diagnostic purposes.     

A platform for dynamic simulation and control of movement based on OpenSim and MATLAB

Numerical simulations play an important role in solving complex engineering problems and have the potential to revolutionize medical decision making and treatment strategies. In this paper, we combine the rapid model-based design, control systems and powerful numerical method strengths of MATLAB/Simulink with the simulation and human movement dynamics strengths of OpenSim by developing a new interface between the two software tools. OpenSim is integrated with Simulink using the MATLAB S-function mechanism, and the interface is demonstrated using both open-loop and closed-loop control systems. While the open-loop system uses MATLAB/Simulink to separately reproduce the OpenSim Forward Dynamics Tool, the closed-loop system adds the unique feature of feedback control to OpenSim, which is necessary for most human movement simulations. An arm model example was successfully used in both open-loop and closed-loop cases. For the open-loop case, the simulation reproduced results from the OpenSim Forward Dynamics Tool with root mean square (RMS) differences of 0.03° for the shoulder elevation angle and 0.06° for the elbow flexion angle. MATLAB's variable step-size integrator reduced the time required to generate the forward dynamic simulation from 7.1s (OpenSim) to 2.9s (MATLAB). For the closed-loop case, a proportional-integral-derivative controller was used to successfully balance a pole on model's hand despite random force disturbances on the pole. The new interface presented here not only integrates the OpenSim and MATLAB/Simulink software tools, but also will allow neuroscientists, physiologists, biomechanists, and physical therapists to adapt and generate new solutions as treatments for musculoskeletal conditions.