Abstract Background Skin secretions of toads are widely used in medicine all over the world for their antiviral, anti-infective, and cardiotonic properties. Because these secretions are mostly ...employed to combat blood parasite infection, it is important to understand their potential toxic effects on human erythrocytes. Therefore, the objective of the current investigation was to elucidate the effects of Duttaphrynus melanostictus (Schneider) skin extracts on the physiology of human erythrocytes. Methods Toads captured from their natural habitat were separated into three groups according to their body size. Hydroalcoholic extracts of toad skin were prepared by reflux heating. These extracts were then evaluated for their hemolytic and hemoglobin denaturation potential. The effects of the extracts on cytosolic and membrane-bound enzymes of human erythrocytes were assessed. Results The hemolysis and hemoglobin denaturation caused by these extracts correlated positively with the respective toad sizes. Extracts from medium and large toads led to increased osmotic fragility even at near iso-osmotic concentrations. Biochemical analysis of hemolysate showed that the treatment induced a shift of metabolic flux toward the glutathione pathway. Analysis of membrane-bound enzymes revealed a significant decrease in the activity of Na+/K+ ATPase and acetylcholinesterase. SDS-PAGE analysis of the erythrocyte membrane did not show the band of tropomodulin for the cells treated with 1000 g/ml extract from large toads. Conclusions In conclusion, the present study demonstrates that the toxicity of toad skin secretions aggravates with the size of the animal and interferes with the physiology of human erythrocytes, leading to their membrane disruption and rapid lysis.
Staphylococcus aureus is an opportunistic pathogen that causes a wide range of infections and food poisoning in humans with antibiotic resistance, specifically to methicillin, compounding the ...problem. Bacteriophages (phages) provide an alternative treatment strategy, but these only infect a limited number of circulating strains and may quickly become ineffective due to bacterial resistance. To overcome these obstacles, engineered phages have been proposed, but new methods are needed for the efficient transformation of large DNA molecules into S. aureus to "boot-up" (i.e., rescue) infectious phages. We presented a new, efficient, and reproducible DNA transformation method, NEST (non-electroporation Staphylococcus transformation), for S. aureus to boot-up purified phage genomic DNA (at least 150 kb in length) and whole yeast-assembled synthetic phage genomes. This method was a powerful new tool for the transformation of DNA in S. aureus and will enable the rapid development of engineered therapeutic phages and phage cocktails against Gram-positive pathogens.
The continued emergence of antibiotic-resistant bacterial pathogens has heightened the urgency for alternative antibacterial strategies. Phages provide an alternative treatment strategy but are difficult to optimize. Synthetic biology approaches have been successfully used to construct and rescue genomes of model phages but only in a limited number of highly transformable host species. In this study, we used a new, reproducible, and efficient transformation method to reconstitute a functional nonmodel Siphophage from a constructed synthetic genome. This method will facilitate the engineering of Staphylococcus and
phages for therapeutic applications and the engineering of Staphylococcus strains by enabling transformation of higher molecular weight DNA to introduce more complex modifications.
Flow fields in cerebral aneurysms can be measured in vivo with phase-contrast MRI (4D Flow MRI), providing 3D anatomical magnitude images as well as 3-directional velocities through the cardiac ...cycle. The low spatial resolution of the 4D Flow MRI data, however, requires the images to be co-registered with higher resolution angiographic data for better segmentation of the blood vessel geometries to adequately quantify relevant flow descriptors such as wall shear stress or flow residence time. Time-of-Flight Magnetic Resonance Angiography (TOF MRA) is a non-invasive technique for visualizing blood vessels without the need to administer contrast agent. Instead TOF uses the blood flow-related enhancement of unsaturated spins entering into an imaging slice as means to generate contrast between the stationary tissue and the moving blood. Because of the higher resolutions, TOF data are often used to assist with the segmentation process needed for the flow analysis and Computational Fluid Dynamics (CFD) modeling. However, presence of slow moving and recirculating blood flow such as in brain aneurysms, especially regions where the blood flow is not perpendicular to the image plane, causes signal loss in these regions. In this work a 3D Curvelet Transform-based image fusion approach is proposed for signal loss artifact reduction of TOF volume data. Experiments show the superiority of the proposed approach in comparison to other multi-resolution 3D Wavelet-based image fusion methodologies. The proposed approach can further facilitate model-based fluid analysis and pre/post-operative treatment of patients with brain aneurysms.
The Gillespie τ-Leaping Method is an approximate algorithm that is faster than the exact Direct Method (DM) due to the progression of the simulation with larger time steps. However, the procedure to ...compute the time leap τ is quite expensive. In this paper, we explore the acceleration of the τ-Leaping Method using Graphics Processing Unit (GPUs) for ultra-large networks (>0.5e(6) reaction channels). We have developed data structures and algorithms that take advantage of the unique hardware architecture and available libraries. Our results show that we obtain a performance gain of over 60x when compared with the best conventional implementations.
Optical coherence tomography (OCT) is an emerging imaging modality that has been widely used in the field of biomedical imaging. In the recent past, it has found uses as a diagnostic tool in ...dermatology, cardiology, and ophthalmology. In this paper we focus on its applications in the field of ophthalmology and retinal imaging. OCT is able to non-invasively produce cross-sectional volumetric images of the tissues which can be used for analysis of tissue structure and properties. Due to the underlying physics, OCT images suffer from a granular pattern, called speckle noise, which restricts the process of interpretation. This requires specialized noise reduction techniques to eliminate the noise while preserving image details. Another major step in OCT image analysis involves the use of segmentation techniques for distinguishing between different structures, especially in retinal OCT volumes. The outcome of this step is usually thickness maps of different retinal layers which are very useful in study of normal/diseased subjects. Lastly, movements of the tissue under imaging as well as the progression of disease in the tissue affect the quality and the proper interpretation of the acquired images which require the use of different image registration techniques. This paper reviews various techniques that are currently used to process raw image data into a form that can be clearly interpreted by clinicians.
Resveratrol has been clinically shown to possess a number of human health benefits. As a result, many attempts have been made to engineer resveratrol production in major cereal grains but have been ...largely unsuccessful. In this study, we report the creation of a transgenic rice plant that accumulates 1.9 µg resveratrol/g in its grain, surpassing the previously reported anti-metabolic syndrome activity of resveratrol through a synergistic interaction between the transgenic resveratrol and the endogenous properties of the rice. Consumption of our transgenic resveratrol-enriched rice significantly improved all aspects of metabolic syndrome and related diseases in animals fed a high-fat diet. Compared with the control animals, the resveratrol-enriched rice reduced body weight, blood glucose, triglycerides, total cholesterol, and LDL-cholesterol by 24.7%, 22%, 37.4%, 27%, and 59.6%, respectively. The resveratrol-enriched rice from our study may thus provide a safe and convenient means of preventing metabolic syndrome and related diseases without major lifestyle changes or the need for daily medications. These results also suggest that future transgenic plants could be improved if the synergistic interactions of the transgene with endogenous traits of the plant are considered in the experimental design.
Outbreaks of infection occur more often than they are reported in most developing countries, largely due to poor diagnostic services. A
species bacteremia outbreak in a newborn unit with high ...mortality was recently encountered at a location being surveilled for childhood bacteremia. These surveillance efforts offered the opportunity to determine the cause of this neonatal outbreak. In this report, we present the whole-genome sequences of New Delhi metallo-β-lactamase (NDM-5)-containing
subsp.
bloodstream isolates from a neonatal bacteremia outbreak at a tertiary hospital in Nigeria and as part of the largest collection of
bloodstream isolates from children in Africa. Comparative analysis of the genetic environment surrounding the NDM-5 genes revealed nearly perfect sequence identity to
-bearing IncX3-type plasmids from other members of the
Carbapenem-resistant
is of global health importance, yet there is a paucity of genome-based studies in Africa. Here we report fatal blood-borne NDM-5-producing
subsp.
infections from Nigeria, Africa. New Delhi metallo-β-lactamase (NDM)-producing
spp. are responsible for high mortality and morbidity, with the NDM-5 variant showing elevated carbapenem resistance. The prevalence of NDM-5 in
has been limited primarily to
, with only one isolate being collected from Africa. During an outbreak of sepsis in a teaching hospital in Nigeria, five NDM-5-producing
subsp.
sequence type 476 isolates were identified. Given the increased resistance profile of these strains, this study highlights the emerging threat of
dissemination in hospital environments. The observation of these NDM-5-producing isolates in Africa stresses the urgency to improve monitoring and clinical practices to reduce or prevent the further spread of resistance.
Optical Coherence Tomography (OCT) is an emerging technique in the field of biomedical imaging, with applications in ophthalmology, dermatology, coronary imaging, etc. OCT images usually suffer from ...a granular pattern, called speckle noise, which restricts the process of interpretation. Therefore the need for speckle noise reduction techniques is of high importance. To the best of our knowledge, use of Independent Component Analysis (ICA) techniques has never been explored for speckle reduction of OCT images. Here, a comparative study of several ICA techniques (InfoMax, JADE, FastICA and SOBI) is provided for noise reduction of retinal OCT images. Having multiple B-scans of the same location, the eye movements are compensated using a rigid registration technique. Then, different ICA techniques are applied to the aggregated set of B-scans for extracting the noise-free image. Signal-to-Noise-Ratio (SNR), Contrast-to-Noise-Ratio (CNR) and Equivalent-Number-of-Looks (ENL), as well as analysis on the computational complexity of the methods, are considered as metrics for comparison. The results show that use of ICA can be beneficial, especially in case of having fewer number of B-scans.
Brain and the gastrointestinal (GI) tract are intimately connected to form a bidirectional neurohumoral communication system. The communication between gut and brain, knows as the gut-brain axis, is ...so well established that the functional status of gut is always related to the condition of brain. The researches on the gut-brain axis were traditionally focused on the psychological status affecting the function of the GI tract. However, recent evidences showed that gut microbiota communicates with the brain via the gut-brain axis to modulate brain development and behavioral phenotypes. These recent findings on the new role of gut microbiota in the gut-brain axis implicate that gut microbiota could associate with brain functions as well as neurological diseases via the gut-brain axis. To elucidate the role of gut microbiota in the gut-brain axis, precise identification of the composition of microbes constituting gut microbiota is an essential step. However, identification of microbes constituting gut microbiota has been the main technological challenge currently due to massive amount of intestinal microbes and the difficulties in culture of gut microbes. Current methods for identification of microbes constituting gut microbiota are dependent on omics analysis methods by using advanced high tech equipment. Here, we review the association of gut microbiota with the gut-brain axis, including the pros and cons of the current high throughput methods for identification of microbes constituting gut microbiota to elucidate the role of gut microbiota in the gut-brain axis.
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