High-Resolution 3D Structure Determination of Kaliotoxin by Solid-State NMR Spectroscopy

High-resolution solid-state NMR spectroscopy can provide structural information of proteins that cannot be studied by X-ray crystallography or solution NMR spectroscopy. Here we demonstrate that it is possible to determine a protein structure by solid-state NMR to a resolution comparable to that by solution NMR. Using an iterative assignment and structure calculation protocol, a large number of distance restraints was extracted from 1H/1H mixing experiments recorded on a single uniformly labeled sample under magic angle spinning conditions. The calculated structure has a coordinate precision of 0.6 Å and 1.3 Å for the backbone and side chain heavy atoms, respectively, and deviates from the structure observed in solution. The approach is expected to be applicable to larger systems enabling the determination of high-resolution structures of amyloid or membrane proteins

Pattern Recognition Software and Techniques for Biological Image Analysis

The increasing prevalence of automated image acquisition systems is enabling new types of microscopy experiments that generate large image datasets. However, there is a perceived lack of robust image analysis systems required to process these diverse datasets. Most automated image analysis systems are tailored for specific types of microscopy, contrast methods, probes, and even cell types. This imposes significant constraints on experimental design, limiting their application to the narrow set of imaging methods for which they were designed. One of the approaches to address these limitations is pattern recognition, which was originally developed for remote sensing, and is increasingly being applied to the biology domain. This approach relies on training a computer to recognize patterns in images rather than developing algorithms or tuning parameters for specific image processing tasks. The generality of this approach promises to enable data mining in extensive image repositories, and provide objective and quantitative imaging assays for routine use. Here, we provide a brief overview of the technologies behind pattern recognition and its use in computer vision for biological and biomedical imaging. We list available software tools that can be used by biologists and suggest practical experimental considerations to make the best use of pattern recognition techniques for imaging assays

Determination of glucose exchange rates and permeability of erythrocyte membrane in preeclampsia and subsequent oxidative stress-related protein damage using dynamic-19F-NMR

The cause of the pregnancy condition preeclampsia (PE) is thought to be endothelial dysfunction caused by oxidative stress. As abnormal glucose tolerance has also been associated with PE, we use a fluorinated-mimic of this metabolite to establish whether any oxidative damage to lipids and proteins in the erythrocyte membrane has increased cell membrane permeability. Data were acquired using 19F Dynamic-NMR (DNMR) to measure exchange of 3-fluoro-3-deoxyglucose (3-FDG) across the membrane of erythrocytes from 10 pregnant women (5 healthy control women, and 5 from women suffering from PE). Magnetisation transfer was measured using the 1D selective inversion and 2D EXSY pulse sequences, over a range of time delays. Integrated intensities from these experiments were used in matrix diagonalisation to estimate the values of the rate constants of exchange and membrane permeability. No significant differences were observed for the rate of exchange of 3-FDG and membrane permeability between healthy pregnant women and those suffering from PE, leading us to conclude that no oxidative damage had occurred at this carrier-protein site in the membrane

Intramural haematoma of the thoracic aorta: who's to be alerted the cardiologist or the cardiac surgeon?

This review article is written so as to present the pathophysiology, the symptomatology and the ways of diagnosis and treatment of a rather rare aortic disease called Intra-Mural Haematoma (IMH). Intramural haematoma is a quite uncommon but potentially lethal aortic disease that can strike as a primary occurrence in hypertensive and atherosclerotic patients to whom there is spontaneous bleeding from vasa vasorum into the aortic wall (media) or less frequently, as the evolution of a penetrating atherosclerotic ulcer (PAU). IMH displays a typical of dissection progress, and could be considered as a precursor of classic aortic dissection. IMH enfeebles the aortic wall and may progress to either outward rupture of the aorta or inward disruption of the intima layer, which ultimately results in aortic dissection. Chest and back acute penetrating pain is the most commonly noticed symptom at patients with IMH. Apart from a transesophageal echocardiography (TEE), a tomographic imaging such as a chest computed tomography (CT), a magnetic resonance (MRI) and most lately a multy detector computed tomography (MDCT) can ensure a quick and accurate diagnosis of IMH. Similar to type A and B aortic dissection, surgery is indicated at patients with type-A IMH, as well as at patients with a persistent and/or recurrent pain. For any other patient (with type-B IMH without an incessant pain and/or without complications), medical treatment is suggested, as applied in the case of aortic dissection. The outcome of IMH in ascending aorta (type A) appears favourable after immediate (emergent or urgent) surgical intervention, but according to international bibliography patients with IMH of the descending aorta (type B) show similar mortality rates to those being subjected to conservative medical or surgical treatment. Endovascular surgery and stent-graft placement is currently indicated in type B IMH

Effect of freezing method on the colour, chlorophylls content and texture of freeze-dried products

Praca przedstawiona w artykule miała na celu określenie wpływu metody zamrażania na barwę, zawartość chlorofili i teksturę produktów liofilizowanych. Jako modelowy surowiec wykorzystano owoce kiwi, które zamrożono z zastosowaniem 3 metod: w zamrażarce bez wymuszonego obiegu powietrza (temp. -22°C), w zamrażarce szokowej z wymuszonym obiegiem powietrza (temp. -70°C) oraz pomiędzy dwoma ogniwami Peltiera 5A do osiągnięcia w środku termicznym temperatury -18°C. Zamrażanie szokowe, pozwoliło uzyskać liofilizat charakteryzujący się największą zawartością barwników, jaśniejszą barwą, a także mniejszą porowatością, co wpłynęło na teksturę analizowanego surowca.The aim of this study was to determine the effect of freezing methods on color, texture and chlorophylls content of freezedried products. As a model material there was used kiwi fruit which was frozen by three methods: in the refrigerator without forced air circulation (temp. -22°C), shock freezer with forced air circulation (temp. -70°C) and between the two Peltier cells 5A to the temperature of -18°C in the thermic center. Shock freezing allowed to obtain the freeze-dried products characterized by the highest content of pigments, lighter color, and lower porosity, which contributed to the texture of the analyzed material

Homonuclear two-dimensional <SUP>1</SUP>H NMR of proteins. Experimental procedures

Experimental techniques used for homonuclear 2D 1H NMR studies of proteins are described. A brief survey of the general strategy for structural studies of proteins by 2D NMR is included. The main part of the paper discusses guidelines for the selection of experimental techniques, the elimination of artifacts and unwanted peaks in protein 2D 1H NMR spectra, suppression of the solvent line in H2O solutions, experimental parameters, numerical data processing before and after Fourier transformation, and suitable presentations of complex 2D NMR spectra

Mixed-ligand complexes of cobalt(III) with dithiocarbamates and a cyclic tetradentate secondary amine

4-Morpholine-, piperidine-, 4-piperazine- and N-methyl- piperazine-dithiocarbamate complexes of Cobalt (III) with 1, 4, 8, 11-tetraazacyclotetradecane, of general formula [Co(Rdtc)cyclam] (ClO4)(2), have been prepared and have been characterized. The complexes adopt cis-octahedral geometry with folded macrocyclic ligand and with the dithiocarbamate bound as a bidentate. trans-influence of the dithiocarbamate ligands was studied by NMR spectroscopy and established the order piperidine-dtc gt 4-morpholine-dtc gt N-methyl-piperazine-dtc