15,115 research outputs found
Identification of an MCM4 homologue expressed specifically in the sexual stage of Plasmodium falciparum.
Mini-chromosome maintenance (MCM) proteins play an essential role in DNA replication initiation. We have isolated a novel gene encoding an MCM-like protein from the human malaria parasite Plasmodium falciparum using the vectorette technique. The gene has no introns and comprises an open reading frame encoding 1005 amino acid residues with a predicted Mr of 115 kDa. The encoded protein, termed PfMCM4, contains all conserved sequences in the MCM family and displays the highest homology to the Cdc54 (MCM4) of Saccharomyces cerevisiae. However, PfMCM4 possesses five unique amino acid inserts with sizes ranging from seven to 75 residues. Southern blotting of genomic DNA digests and chromosomal separations showed that the Pfmcm4 gene is present as a single copy per haploid genome and is located on chromosome 13. A 4000-nucleotide transcript of this gene is expressed specifically in the sexual erythrocytic stage, indicating that PfMCM4 may be involved in gametogenesis in which DNA is quickly replicated
Isolation and characterisation of a cAMP-dependent protein kinase catalytic subunit gene from Plasmodium falciparum.
Integrating the Kinect camera, gesture recognition and mobile devices for interactive discussion
Session H4CThe Microsoft Kinect camera is a revolutionary and useful depth camera giving new user experience of interactive gaming on the Xbox platform through gesture or motion detection. Besides the infrared-based depth camera, an array of built-in microphones for voice command is installed along the horizontal bar of the Kinect camera. As a result, there are increasing interests to apply the Kinect camera for various real-life applications including the control of squirt guns for outdoor swimming pools. In additional to the Kinect camera, mobile devices such as the smartphones readily integrated with motion sensors have been used for different real-time control tasks like the remote control of robots. In this project, we propose to integrate the Microsoft Kinect camera together with the smartphones as intelligent control for interactive discussion or presentation for the future e-learning system. To demonstrate the feasibility of our proposal, a prototype of our proposed gesture recognition and command specification software is built using the C# language on the MS.NET platform, and will be evaluated with a careful plan. Furthermore, there are many interesting directions for further investigation of our proposal. © 2012 IEEE.published_or_final_versio
Distinct physicochemical characteristics of different beef from Qinchuan cattle carcass
A total of 30 Qinchuan cattle were used to investigate the physicochemical characteristics of beef from three different parts of cattle carcass, namely longissimus dorsi (LD), serratus ventralis (SV) and semitendinosus (ST). Multiple parameters were ranked in the descending order of ST > SV > LD, and include muscle pH, protein, ash, drip loss, cooking loss, shear force and hydroxyproline (Hyp). In contrast, water, fat, lightness (L*) and redness (a*) was in the opposite order. C18:1 and C16:0 were the main intramuscular fatty acids (FA), and C19 - C22 were undetectable. The saturated fatty acids (SFA) content were ranked in the descending order of LD > SV > ST, whereas unsaturated fatty acids (UFA) were the opposite. The essential amino acid (EAA) content were ranked in the descending order of ST > SV ≥ LD. No significant differences in the contents of mineral elements were observed in LD, SV and ST. The ranking patterns were similar in both males and females. Taken together, these results revealed significant differences in physicochemical properties of LD, SV and ST, except the mineral elements.Key words: Cattle, Qinchuan breed, carcass, different beef, physicochemical characteristics
Phosphogenesis in the 2460 and 2728 million-year-old banded iron formations as evidence for biological cycling of phosphate in the early biosphere
The banded iron formation deposited during the first 2 billion years of Earth's history holds the key to understanding the interplay between the geosphere and the early biosphere at large geological timescales. The earliest ore-scale phosphorite depositions formed almost at approximately 2.0-2.2 billion years ago bear evidence for the earliest bloom of aerobic life. The cycling of nutrient phosphorus and how it constrained primary productivity in the anaerobic world of Archean-Palaeoproterozoic eons are still open questions. The controversy centers about whether the precipitation of ultrafine ferric oxyhydroxide due to the microbial Fe(II) oxidation in oceans earlier than 1.9 billion years substantially sequestrated phosphate, and whether this process significantly limited the primary productivity of the early biosphere. In this study, we report apatite radial flowers of a few micrometers in the 2728 million-year-old Abitibi banded iron formation and the 2460 million-year-old Kuruman banded iron formation and their similarities to those in the 535 million-year-old Lower Cambrian phosphorite. The lithology of the 535 Million-year-old phosphorite as a biosignature bears abundant biomarkers that reveal the possible similar biogeochemical cycling of phosphorus in the Later Archean and Palaeoproterozoic oceans. These apatite radial flowers represent the primary precipitation of phosphate derived from the phytoplankton blooms in the euphotic zones of Neoarchean and Palaoeproterozoic oceans. The unbiased distributions of the apatite radial flowers within sub-millimeter bands do not support the idea of an Archean Crisis of Phosphate. This is the first report of the microbial mediated mineralization of phosphorus before the Great Oxidation Event when the whole biosphere was still dominated by anaerobic microorganisms.published_or_final_versio
Influence of optic-flow information beyond the velocity field on the active control of heading
Talk Session - Action and virtual environments: 11.2We examined both the sufficiency of the optic-flow velocity field and the influence of optic-flow information beyond the velocity field on the active control of heading. The display simulated a vehicle traveling on a circular path through a random-dot 3D cloud …postprin
Analysis on GNSS receiver with the principles of signal and information
In the paper, principles of signal and information were introduced to the design of GNSS receiver. Analyze Antenna and radio frequency (RF) front-end with the perspective of transmission link, Understand the baseband processing though signal modulate and demodulate, design the navigation calculation utilized the information pick-up and disposal, and research the receiver system by the inherent connection between signal and information. New ways and means would be developed though these researches. © (2013) Trans Tech Publications, Switzerland
Identification of a second proliferating cell nuclear antigen in the human malarial pathogen Plasmodium falciparum.
Proliferating cell nuclear antigen seems to exist as a single form in higher eukaryotic cells and plays multiple roles in nucleic acid metabolism. We have identified a second additional proliferating cell nuclear antigen (PfPCNA2) in Plasmodium falciparum on the basis of several lines of evidence. (1) PfPCNA2, consisting of 264 amino acid residues with a predicted molecular mass of 30.2kDa, shares only 29% identity and 53% similarity with PfPCNA1 at the amino acid level. (2) Southern blot analyses revealed that the hybridisation pattern of the Pfpcna2 gene is completely different from that of the Pfpcna1 gene. (3) Chromosomal localisation studies showed that Pfpcna2 is located on chromosome 12 while Pfpcna1 is located on chromosome 13. Northern blot analyses revealed two different transcripts of Pfpcna2, one expressed in both asexual and sexual erythrocytic stages, while the other existed only in the sexual stage, implying that PfPCNA2 may play multiple roles in DNA metabolism in different stages of the parasite. Recombinant protein of PfPCNA2, overexpressed in Escherichia coli, has been purified to near homogeneity and shown to form an oligomer, probably a trimer, as revealed by a size-exclusion chromatography and a native gel electrophoresis, suggesting that PfPCNA2, like its higher eukaryotic counterparts, may serve as a sliding platform which is capable of interaction with diverse proteins and regulation of their activities
Effects of test conditions on shear behaviour of composite soil
Test conditions, such as shearing rate and normal stress, have been long recognised as influencing the measured shear strength of clays and sands. However, their influence on composite soils, which have a wide range of particle sizes, has attracted much less attention from researchers. In this study, a total of 35 direct shear tests at different shearing rates under different normal stresses were conducted on specimens prepared by mixing different proportions of kaolin and glass beads. The changes in volume and water content of sheared specimens and the mesostructure of shear surfaces were studied. The results reveal a positive correlation between volume change and deviation of water content between the shear zone and outer zones, suggesting that the shear-induced volume change occurred primarily in the shear zones. Moreover, high normal stress and low shearing rate produced a relatively small void ratio in the shear zones, facilitating volumetric contraction of the specimen and the development of polished and evenly slickensided shear surfaces. In addition, the residual friction angle of the specimens tested was found to decrease with the increase in normal stress. The high shearing rate caused an increase in residual strength in specimens with low fines fraction, and reduced it in specimens with high fines fraction.published_or_final_versio
Inhibitory Effect of a French Maritime Pine Bark Extract-Based Nutritional Supplement on TNF-α-Induced Inflammation and Oxidative Stress in Human Coronary Artery Endothelial Cells
© 2015 Kristine C. Y. McGrath et al. Oxidative stress and inflammation, leading to endothelial dysfunction, contribute to the pathogenesis of atherosclerosis. The popularity of natural product supplements has increased in recent years, especially those with purported anti-inflammatory and/or antioxidant effects. The efficacy and mechanism of many of these products are not yet well understood. In this study, we tested the antioxidant and anti-inflammatory effects of a supplement, HIPER Health Supplement (HIPER), on cytokine-induced inflammation and oxidative stress in human coronary artery endothelial cells (HCAECs). HIPER is a mixture of French maritime pine bark extract (PBE), honey, aloe vera, and papaya extract. Treatment for 24 hours with HIPER reduced TNF-α-induced reactive oxygen species (ROS) generation that was associated with decreased NADPH oxidase 4 and increased superoxide dismutase-1 expression. HIPER inhibited TNF-α induced monocyte adhesion to HCAECs that was in keeping with decreased expression of vascular cell adhesion molecule-1 and intercellular cell adhesion molecule-1 and decreased nuclear factor-kappa B (NF-B) activation. Further investigation of mechanism showed HIPER reduced TNF-α induced IBα and p38 and MEK1/2 MAP kinases phosphorylation. Our findings show that HIPER has potent inhibitory effects on HCAECs inflammatory and oxidative stress responses that may protect against endothelial dysfunction that underlies early atherosclerotic lesion formation
- …