Rotational Viscosity in Linear Irreversible Thermodynamics and its Application to Neutron Stars

A generalized analysis of the local entropy production of a simple fluid is used to show that, if intrinsic angular momentum is taken into account, rotational viscosity must arise in the linear non-equilibrium regime. As a consequence, the stress tensor of dense rotating matter, such as the one present in neutron stars, posseses a significant non-vansishing antisymmetrical part. A simple argument suggests that, due to the extreme magnetic fields present in neutron stars, the relaxation time associated to rotational viscosity is large (approx 10^{21} s). The formalism leads to generalized Navier-Stokes equations useful in neutron star physics which involve vorticity in the linear regime.Comment: 6 pages Revtex; to appear J. Nonequilibrium Therm

Human granulocyte colony stimulating factor (hG-CSF): cloning, overexpression, purification and characterization

<p>Abstract</p> <p>Background</p> <p>Biopharmaceutical drugs are mainly recombinant proteins produced by biotechnological tools. The patents of many biopharmaceuticals have expired, and biosimilars are thus currently being developed. Human granulocyte colony stimulating factor (hG-CSF) is a hematopoietic cytokine that acts on cells of the neutrophil lineage causing proliferation and differentiation of committed precursor cells and activation of mature neutrophils. Recombinant hG-CSF has been produced in genetically engineered <it>Escherichia coli </it>(Filgrastim) and successfully used to treat cancer patients suffering from chemotherapy-induced neutropenia. Filgrastim is a 175 amino acid protein, containing an extra N-terminal methionine, which is needed for expression in <it>E. coli</it>. Here we describe a simple and low-cost process that is amenable to scaling-up for the production and purification of homogeneous and active recombinant hG-CSF expressed in <it>E. coli </it>cells.</p> <p>Results</p> <p>Here we describe cloning of the human granulocyte colony-stimulating factor coding DNA sequence, protein expression in <it>E. coli </it>BL21(DE3) host cells in the absence of isopropyl-β-D-thiogalactopyranoside (IPTG) induction, efficient isolation and solubilization of inclusion bodies by a multi-step washing procedure, and a purification protocol using a single cationic exchange column. Characterization of homogeneous rhG-CSF by size exclusion and reverse phase chromatography showed similar yields to the standard. The immunoassay and N-terminal sequencing confirmed the identity of rhG-CSF. The biological activity assay, <it>in vivo</it>, showed an equivalent biological effect (109.4%) to the standard reference rhG-CSF. The homogeneous rhG-CSF protein yield was 3.2 mg of bioactive protein per liter of cell culture.</p> <p>Conclusion</p> <p>The recombinant protein expression in the absence of IPTG induction is advantageous since cost is reduced, and the protein purification protocol using a single chromatographic step should reduce cost even further for large scale production. The physicochemical, immunological and biological analyses showed that this protocol can be useful to develop therapeutic bioproducts. In summary, the combination of different experimental strategies presented here allowed an efficient and cost-effective protocol for rhG-CSF production. These data may be of interest to biopharmaceutical companies interested in developing biosimilars and healthcare community.</p

Effects of restraint stress on the daily rhythm of hydrolysis of adenine nucleotides in rat serum

<p>Abstract</p> <p>Background</p> <p>Adenosine 5-triphosphate (ATP) and its breakdown products ADP and adenosine can act as extracellular messengers in a range of biological processes. Extracellular adenine nucleotides are metabolized by a number of enzymes including NTPDases and 5'-nucleotidase, which are considered to be the major regulators of purinergic signaling in the blood. Previous work by our group demonstrated that ATPase and ADPase activities in rat serum exhibit a 24-h temporal pattern, with higher enzyme activity during the dark (activity) phase. It was found that stress can cause disruptions in biological circadian rhythms and in the cardiovascular system. Therefore, the aim of the present study was to examine the influence of acute stress exposure upon temporal patterns of NTPDase and 5-nucleotidase enzyme activities in rat blood serum.</p> <p>Methods</p> <p>Adult male Wistar rats were divided into 4 groups: ZT0, ZT6, ZT12 and ZT18. Each group was subdivided in 4 groups: control, immediately, 6 h and 24 h after one hour of restraint stress. ATP, ADP and AMP hydrolysis were assayed in the serum.</p> <p>Results</p> <p>All stressed groups showed significant decreases in all enzyme activities at ZT 12 and ZT 18 when compared with control.</p> <p>Conclusion</p> <p>Acute stress provokes a decrease in nucleotidase activities dependent on the time that this stress occurs and this effect appears to persist for at least 24 hours. Stress can change levels of nucleotides, related to increased frequency of cardiovascular events during the activity phase. Altered levels of nucleotides in serum may be involved in cardiovascular events more frequent during the activity phase in mammals, and with their etiology linked to stress.</p

High yielding synthesis of N-ethyl dehydroamino acids

Recently we reported the use of a sequence of alkylation and dehydration methodologies to obtain N-ethyl-α, β-dehydroamino acid derivatives. The application of this N-alkylation procedure to several methyl esters of β, β-dibromo and β--bromo, β-substituted dehydroamino acids protected with standard amine protecting groups was subsequently reported. The corresponding N-ethyl, β-bromo dehydroamino acid derivatives were obtained in fair to high yields and some were used as substrates in Suzuki cross coupling reactions to give N-ethyl, β, β-disubstituted dehydroalanine derivatives. Herein, we further explore N-ethylation of β-halo dehydroamino acid derivatives using triethyloxonium tetrafluoroborate as alkylating agent but substituting N,N-diisopropylethylamine for potassium tert-butoxide as auxiliary base. In these conditions, for all β-halo dehydroamino acid derivatives, reactions were complete and the N-ethylated derivative could be isolated in high yield. This method was also applied for N-ethylation of non-halogenated dehydroamino acids. Again, with all compounds the reactions were complete and the N-ethyl dehydroamino acid derivatives could be isolated in high yields. Some of these N-ethyl dehydroamino acid methyl ester derivatives were converted in high yields to their corresponding acids and coupled to an amino acid methyl ester to give N-ethyl dehydrodipeptide derivatives in good yields. Thus, this method constitutes a general procedure for high yielding synthesis of N-ethylated dehydroamino acids, which can be further applied in peptide synthesis.Foundation for Science and Technology (FCT)-Portugal and Fundo Europeu de Desenvolvimento Regional (FEDER) for financial support to Chemistry Centre of University of Minho. The NMR spectrometer Bruker Avance II+ 400 is part of the National NMR Network and was purchased in the framework of the National Program for Scientific Re-equipment; contract REDE/1517/RMN/2005, with funds from POCI 2010, FEDER and FCT

Late onset and early onset aura: the same disorder

Late onset aura (LOA) is usually considered benign but raises diagnostic uncertainties. We compared individuals with LOA (>45 years of age at aura onset) with those of early onset (EOA) in clinical features, vascular risk factors and imaging, in a retrospective study design including patients with migraine aura and age >44 years at first visit. In 77 cases (51 EOA and 26 LOA), no differences were found in gender distribution, family or personal history of migraine without aura, type of aura symptoms or imaging findings. LOA patients’ were more likely to not fulfil all ICHD-II aura criteria and to lack headache. This data suggest that LOA and EOA are overall identical but there are differences in presentation that deserve a better characterization by a prospective study

Some Like It Fat: Comparative Ultrastructure of the Embryo in Two Demosponges of the Genus Mycale (Order Poecilosclerida) from Antarctica and the Caribbean

0000-0002-7993-1523© 2015 Riesgo et al. This is an open access article distributed under the terms of the Creative Commons Attribution License [4.0], which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article

An apoplastic fluid extraction method for the characterization of grapevine leaves proteome and metabolome from a single sample

The analysis of complex biological systems keeps challenging researchers. The main goal of systems biology is to decipher interactions within cells, by integrating datasets from large scale analytical approaches including transcriptomics, proteomics and metabolomics andmore specialized ‘OMICS’ such as epigenomics and lipidomics. Studying different cellular compartments allows a broader understanding of cell dynamics. Plant apoplast, the cellular compartment external to the plasma membrane including the cell wall, is particularly demanding to analyze. Despite our knowledge on apoplast involvement on several processes from cell growth to stress responses, its dynamics is still poorly known due to the lack of efficient extraction processes adequate to each plant system.Analyzing woody plants such as grapevine raises even more challenges. Grapevine is among the most important fruit crops worldwide and awider characterization of its apoplast is essential for a deeper understanding of its physiology and cellular mechanisms. Here, we describe, for the first time, a vacuum-infiltrationcentrifugationmethod that allows a simultaneous extraction of grapevine apoplastic proteins and metabolites from leaves on a single sample, compatible with high-throughput mass spectrometry analyses. The extracted apoplast from two grapevine cultivars, Vitis vinifera cv ‘Trincadeira’ and ‘Regent’, was directly used for proteomics and metabolomics analysis. The proteome was analyzed by nanoLC-MS/MS and more than 700 common proteinswere identified, with highly diverse biological functions. The metabolome profile through FT-ICR-MS allowed the identification of 514 unique putative compounds revealing a broad spectrum of molecular classesinfo:eu-repo/semantics/publishedVersio