Nucleotide Phosphohydrolase in Purified Vaccinia Virus

Purified infectious vaccinia virus has been shown to contain an enzyme or enzymes that remove the terminal phosphate group from adenosine triphosphate (ATP), guanosine triphosphate (GTP), uridine triphosphate (UTP), and cytidine triphosphate (CTP). The K(m) for ATP of this enzyme is 5.5 x 10(-4)m, and the relative rates of the reaction with ATP, GTP, UTP, and CTP are 1.00, 0.34, 0.15, and 0.29, respectively. The virus enzyme does not react with any of the diphosphates. The rate of the reaction is proportional to the amount of virus added and is linear for 130 min. The virus nucleotide phosphohydrolase activity is greatly stimulated by Mg(++) and very slightly stimulated by Ca(++). The small residual activity observed in the absence of divalent cations is completely inhibited by ethylenediaminetetraacetic acid. Neither Na(+) nor K(+) ions, nor any mixture of these, was found to stimulate the reaction significantly, and ouabain, at 10(-4)m, inhibited the reaction by only 27%. The response of the vaccinia enzyme to mono- and divalent cations and to ouabain indicates that the vaccinia enzyme has different properties from those associated with microsomes and mitochondria.     

A Novel Algorithm for Movement Artifact Removal in ECG Signals Acquired from Wearable Systems Applied to Horses

This study reports on a novel method to detect and reduce the contribution of movement artifact (MA) in electrocardiogram (ECG) recordings gathered from horses in free movement conditions. We propose a model that integrates cardiovascular and movement information to estimate the MA contribution. Specifically, ECG and physical activity are continuously acquired from seven horses through a wearable system. Such a system employs completely integrated textile electrodes to monitor ECG and is also equipped with a triaxial accelerometer for movement monitoring. In the literature, the most used technique to remove movement artifacts, when noise bandwidth overlaps the primary source bandwidth, is the adaptive filter. In this study we propose a new algorithm, hereinafter called Stationary Wavelet Movement Artifact Reduction (SWMAR), where the Stationary Wavelet Transform (SWT) decomposition algorithm is employed to identify and remove movement artifacts from ECG signals in horses. A comparative analysis with the Normalized Least Mean Square Adaptive Filter technique (NLMSAF) is performed as well. Results achieved on seven hours of recordings showed a reduction greater than 40% of MA percentage (between before- and after- the application of the proposed algorithm). Moreover, the comparative analysis with the NLMSAF, applied to the same ECG recordings, showed a greater reduction of MA percentage in favour of SWMAR with a statistical significant difference (p–value < 0.0.5).     

2′,3′-Isopropylidene Group,A Molecular Scaffold to Study the Activity of Adenosine and Adenylate Deaminase on Adenosine Analogues Modified in the Ribose Moiety

2 ′,3 ′-Isopropylidene group can be used as a molecular scaffold for the introduction of modifications at 5 ′ and 1 ′ positions of adenosine and these modified nucleosides are used to evaluate the biocatalytic activity of adenosine and adenylate deaminase.     

Neuropathological findings processed by artificial neural networks (ANNs) can perfectly distinguish Alzheimer's patients from controls in the Nun Study

Background  

Many reports have described that there are fewer differences in AD brain neuropathologic lesions between AD patients and control subjects aged 80 years and older, as compared with the considerable differences between younger persons with AD and controls. In fact some investigators have suggested that since neurofibrillary tangles (NFT) can be identified in the brains of non-demented elderly subjects they should be considered as a consequence of the aging process. At present, there are no universally accepted neuropathological criteria which can mathematically differentiate AD from healthy brain in the oldest old.     

Synchrotron-Based Techniques Shed Light on Mechanisms of Plant Sensitivity and Tolerance to High Manganese in the Root Environment

Plant species differ in response to high available manganese (Mn), but the mechanisms of sensitivity and tolerance are poorly understood. In solution culture, greater than or equal to 30 µm Mn decreased the growth of soybean (Glycine max), but white lupin (Lupinus albus), narrow-leafed lupin (Lupin angustifolius), and sunflower (Helianthus annuus) grew well at 100 µm Mn. Differences in species’ tolerance to high Mn could not be explained simply by differences in root, stem, or leaf Mn status, being 8.6, 17.1, 6.8, and 9.5 mmol kg^–1 leaf fresh mass at 100 µm Mn. Furthermore, x-ray absorption near edge structure analyses identified the predominance of Mn(II), bound mostly to malate or citrate, in roots and stems of all four species. Rather, differences in tolerance were due to variations in Mn distribution and speciation within leaves. In Mn-sensitive soybean, in situ analysis of fresh leaves using x-ray fluorescence microscopy combined with x-ray absorption near edge structure showed high Mn in the veins, and manganite [Mn(III)] accumulated in necrotic lesions apparently through low Mn sequestration in vacuoles or other vesicles. In the two lupin species, most Mn accumulated in vacuoles as either soluble Mn(II) malate or citrate. In sunflower, Mn was sequestered as manganite at the base of nonglandular trichomes. Hence, tolerance to high Mn was ascribed to effective sinks for Mn in leaves, as Mn(II) within vacuoles or through oxidation of Mn(II) to Mn(III) in trichomes. These two mechanisms prevented Mn accumulation in the cytoplasm and apoplast, thereby ensuring tolerance to high Mn in the root environment.Manganese (Mn) is an essential element for plant growth, but its availability differs greatly in space and time, depending largely on the nature and amount of Mn minerals present and on the soil’s pH and redox potential. With an elaborate chemistry, Mn forms complexes with many organic and inorganic ligands. In soils, Mn has three common oxidation states, Mn(II), Mn(III), and Mn(IV), which form hydrated oxides of mixed valency; Mn is present also as numerous carbonates, silicates, sulfates, and phosphates (Lindsay, 1979). Cationic Mn²⁺ is the most common form readily absorbed by plant roots (Clarkson, 1988). The toxicity of Mn occurs in acid or waterlogged soils high in Mn minerals.Many plants have mechanisms to accommodate the large differences in Mn²⁺ in soils. At low available Mn, uptake is increased in some Poaceae by excretion of phytosiderophores of the mugineic acid family (Takahashi et al., 2003), with root phytase exudation also potentially important for acquisition of Mn when Mn availability is limited (George et al., 2014). Mechanisms in other plants include the ability of roots to decrease rhizosphere pH or excrete organic ligands (Neumann and Romheld, 2012; Lambers et al., 2015). However, the relative importance of the many complexes on Mn uptake remains unclear. Toxicity results from high Mn in leaf cell walls (Wissemeier et al., 1992; Wissemeier and Horst, 1992) and through adverse effects on symplastic proteins (Führs et al., 2008). Many plants have mechanisms that limit the adverse effects of high Mn²⁺ in soils, with numerous ligands involved in its translocation and that of other essential cations (Haydon and Cobbett, 2007). Edwards and Asher (1982) classified a range of crop and pasture species based on their ability to deal with high Mn as those that (1) limit Mn from entering the roots, (2) retain Mn in the roots, or (3) tolerate high Mn in the shoots. At the extreme are plants that hyperaccumulate more than 10,000 mg Mn kg^–1 on a dry mass (DM) basis in foliar tissues without metabolic damage (Fernando et al., 2013; van der Ent et al., 2013). Based on 15% DM of leaves, this equates to 12.1 mmol kg^–1 on a fresh mass (FM) basis. Celosia argentia, a species adapted to growth on Mn-contaminated mine tailings, accumulated more than 20,000 mg kg^–1 Mn in leaves (Liu et al., 2014). Tolerance of high Mn in shoots of some Mn hyperaccumulators has been found to occur through binding to ligands (such as malate or citrate) or sequestration in the vacuole (Fernando et al., 2010).Characteristic symptoms of Mn toxicity include chlorotic and distorted leaves with small necrotic lesions. These lesions have been shown in cowpea (Vigna unguiculata) to contain oxidized Mn and callose (Wissemeier et al., 1992), which forms as a reaction to high intracellular Ca (Kartusch, 2003). The necrotic lesions result mainly from oxidized phenolics (Wissemeier and Horst, 1992) and increased peroxidase activity in the apoplast (Horst et al., 1999). With a critical solution concentration for toxicity (10% growth reduction) of no more than 9 µm Mn, Edwards and Asher (1982) found that cotton (Gossypium hirsutum), bean (Phaseolus vulgaris), cowpea, and soybean (Glycine max) were the most sensitive species of 13 crop and pasture plants grown for 18 to 31 d at constant Mn in solution culture. By contrast, the critical concentration for sunflower (Helianthus annuus) was 7 times higher at 65 µm Mn. Sunflower was the first species found to tolerate high Mn through its sequestration in the trichomes on stems, petioles, and leaves (Blamey et al., 1986). The suspected accumulation of Mn was confirmed using wavelength dispersive x-ray spectroscopy with darkening inferred as due to insoluble higher oxides of Mn. Similarly, high Mn results in darkened trichomes of cucumber (Cucumis sativus) leaves due to oxidized Mn, as shown by the colorimetric benzidine test (Horiguchi, 1987). Watermelon (Citrullus lanatus; Elamin and Wilcox, 1986b), but not muskmelon (Citrullus melo; Elamin and Wilcox, 1986a), grown at high Mn also develops small dark spots around the leaf trichomes. Other species that sequester Mn in the trichomes include common nettle (Urtica dioica; Hughes and Williams, 1988) and Alyssum murale, a Ni hyperaccumulator (Broadhurst et al., 2009; McNear and Küpper, 2014). Thus, some plants in four families, Asteraceae, Cucurbitaceae, Urticaceae, and Brassicaceae, tolerate high Mn in shoots through Mn sequestration in or around the trichomes. The mechanisms may differ, however, because the high Mn present during development of common nettle stinging hairs decreases as plants mature (Hughes and Williams, 1988).Recently developed techniques, including those based on synchrotron radiation, allow investigations of the distribution and speciation of Mn in planta, with most research to date focused on Mn hyperaccumulators (Fernando et al., 2013). For example, Fernando et al. (2010) used x-ray absorption near-edge spectroscopy (XANES) to confirm the widely accepted view that Mn(II) predominates in seven Mn hyperaccumulators. Synchrotron-based x-ray fluorescence microspectroscopy (µ-XRF) was used by McNear and Küpper (2014) to show that the basal region of trichomes of A. murale plants grown at no more than 10 µm Mn contained Mn(II) complexed with phosphate. At 50 µm Mn in solution, however, the increased amount of Mn that had accumulated around the trichomes was present as Mn(III). Few studies, however, have used synchrotron-based techniques to investigate the mechanisms of Mn toxicity and tolerance in agronomic species despite their importance for food production in regions where soils are acidic or intermittently waterlogged. One study on cowpea, with a critical toxicity concentration of only 2 µm Mn (Edwards and Asher, 1982), has shown an accumulation of Mn-citrate in the root cap and associated mucigel within 5 min of exposure to 150 µm Mn (Kopittke et al., 2013).This study aimed to determine the distribution and speciation of Mn in fresh roots, stems, and leaves of four crop species, soybean, white lupin (Lupinus albus), narrow-leafed lupin (Lupinus angustifolius), and sunflower, which differ in tolerance to high Mn. It was hypothesized that Mn distribution and speciation would differ between Mn-sensitive soybean and the three other species. Furthermore, we considered it likely that the Mn tolerance mechanism of sunflower would differ from those of the two lupin species, which do not have darkened trichomes when grown at high Mn.     

Non-invasive Parenchymal,Vascular and Metabolic High-frequency Ultrasound and Photoacoustic Rat Deep Brain Imaging

Photoacoustics and high frequency ultrasound stands out as powerful tools for neurobiological applications enabling high-resolution imaging on the central nervous system of small animals. However, transdermal and transcranial neuroimaging is frequently affected by low sensitivity, image aberrations and loss of space resolution, requiring scalp or even skull removal before imaging. To overcome this challenge, a new protocol is presented to gain significant insights in brain hemodynamics by photoacoustic and high-frequency ultrasounds imaging with the animal skin and skull intact. The procedure relies on the passage of ultrasound (US) waves and laser directly through the fissures that are naturally present on the animal cranium. By juxtaposing the imaging transducer device exactly in correspondence to these selected areas where the skull has a reduced thickness or is totally absent, one can acquire high quality deep images and explore internal brain regions that are usually difficult to anatomically or functionally describe without an invasive approach. By applying this experimental procedure, significant data can be collected in both sonic and optoacoustic modalities, enabling to image the parenchymal and the vascular anatomy far below the head surface. Deep brain features such as parenchymal convolutions and fissures separating the lobes were clearly visible. Moreover, the configuration of large and small blood vessels was imaged at several millimeters of depth, and precise information were collected about blood fluxes, vascular stream velocities and the hemoglobin chemical state. This repertoire of data could be crucial in several research contests, ranging from brain vascular disease studies to experimental techniques involving the systemic administration of exogenous chemicals or other objects endowed with imaging contrast enhancement properties. In conclusion, thanks to the presented protocol, the US and PA techniques become an attractive noninvasive performance-competitive means for cortical and internal brain imaging, retaining a significant potential in many neurologic fields.     

The investigation of structure–activity relationship of polyamine-targeted synthetic compounds from different chemical groups

Amino Acids - The polyamine (PA) metabolism is involved in cell proliferation and differentiation. Increased cellular PA levels are observed in different types of cancers. Products of PA oxidation...