RESUMO
Extracellular nucleotides act as danger signals that orchestrate inflammation by purinergic receptor activation. The expression pattern of different purinergic receptors may correlate with a pro- or anti-inflammatory phenotype. Macrophages function as pro-inflammatory M1 macrophages (M1) or anti-inflammatory M2 macrophages (M2). The present study found that murine bone marrow-derived macrophages express a unique purinergic receptor profile during in vitro polarization. As assessed by real-time polymerase chain reaction (PCR), Gαs-coupled P1 receptors A2A and A2B are upregulated in M1 and M2 compared to M0, but A2A 15 times higher in M1. The ionotropic P2 receptor P2X5 is selectively upregulated in M1- and M2-polarized macrophages. P2X7 is temporarily expressed in M1 macrophages. Metabotropic P2Y receptors showed a distinct expression profile in M1 and M2-polarized macrophages: Gαq coupled P2Y1 and P2Y6 are exclusively upregulated in M2, whereas Gαi P2Y13 and P2Y14 are overexpressed in M1. This consequently leads to functional differences between M1 and M2 in response to adenosine di-phosphate stimulation (ADP): In contrast to M1, M2 showed increased cytoplasmatic calcium after ADP stimulation. In the present study we show that bone marrow-derived macrophages express a unique repertoire of purinergic receptors. We show for the first time that the repertoire of purinergic receptors is highly flexible and quickly adapts upon pro- and anti-inflammatory macrophage differentiation with functional consequences to nucleotide stimulation.
Assuntos
Mediadores da Inflamação/metabolismo , Macrófagos/metabolismo , Receptores Purinérgicos/biossíntese , Transcriptoma/fisiologia , Animais , Polaridade Celular/fisiologia , Células Cultivadas , Camundongos , Receptores Purinérgicos/genéticaRESUMO
Their surface activity enables proteins to form and stabilize foam, which can be used for in situ product separation or foam fractionation. Thus, it would be highly desirable to predict the surface activity of proteins based on their molecular properties like hydrophobicity, amphilicity, or structure on primary, secondary, and tertiary level. Ionic strength and pH were adjusted to gain maximum surface activity. The surface activity decreased in the order α lactalbumin > ßlactoglobulinâ¯>â¯trypsinogenâ¯>â¯papain. For the theoretical analysis, the database was extended by including 2 hydrophobins into the investigation, since they are known to exhibit an outstanding surface activity. No relation to the macroscopic behavior was found considering the hydrophobicity. I.e., the non-hydrophobins did not differ significantly from each other, and from the hydrophobins, one was significantly hydrophobic, and the other was significantly hydrophilic. Also, no relations were found considering the amphilicity of the secondary structure elements. However, taking into account the tertiary protein structure, it was found that for most of the proteins investigated, the presence of non-buried amphiphilic secondary structure elements in combination with a certain amount of flexibility correlates with the surface activity.
Assuntos
Proteínas Fúngicas , Proteínas Fúngicas/metabolismo , Interações Hidrofóbicas e Hidrofílicas , Estrutura Secundária de Proteína , Estrutura Terciária de ProteínaRESUMO
We report the improved direct access to red-emitting BOIMPY fluorophores (λ ≈ 600 nm) via a simple one-pot approach. Our method starts from easily available benzimidazole-2-carboxylic acids and not only greatly improves the overall yields but also saves both costly reagents and time. In addition, the method facilitates the synthesis of novel unsymmetrical BOIMPY motifs. Therefore, these BOIMPY scaffolds derived from the BODIPY core become more accessible for applications as fluorophores at the appealing red edge of the visible spectrum.
RESUMO
A major difference between proteins and surfactants is that proteins are capable of changing their structure during refolding processes in the adsorbed state. It is often reported that these interfacial structure changes increase the surface activity of proteins. In order to investigate this, the surface activity of 5 proteins was determined in foam fractionation experiments, where pH and ionic strength were adjusted separately to gain the maximum surface activity for each protein. Infrared Reflection Absorption Spectroscopy was performed for each protein to analyze the changes in secondary structure after adsorption. In order to investigate quick structural changes, transmission Fourier Transform Infrared spectroscopy was performed to gain information about the secondary structure of the dissolved, non-adsorbed proteins. It was found that most proteins maintain a native-like conformation when adsorbed at the interface. With increasing time, most of the proteins investigated increased the amount of ß-sheets at the interface. This slow process went along with a slow increase in surface pressure. A correlation between structural changes on molecular level and surface activity on macroscopic level could not be found. However, the absolute increase of surface pressure at the very beginning of the adsorption process correlated with the surface activity of the proteins, suggesting that the slow processes on molecular level do not have a considerable impact on macroscopic surface activity.
Assuntos
Lactalbumina/química , Propriedades de Superfície , Eletroforese em Gel de Poliacrilamida , Modelos Estruturais , Conformação Proteica , Estrutura Secundária de Proteína , Espectrofotometria Infravermelho , Espectroscopia de Infravermelho com Transformada de Fourier , Relação Estrutura-AtividadeRESUMO
Surface activity is an intrinsic protein feature, leading to the capability of aqueous protein solutions to form foam. This feature provides opportunities for downstream processing, such as usage of foam fractionation for purification. In order to investigate the impact of the surface activity on the performance of the foam fractionation process, protein solutions with different surface activity were produced by different thermal denaturation of aqueous ß-lactoglobulin solutions. The effectiveness of the denaturation procedure was verified with circular dichroic spectroscopy, and the impact on surface activity was determined via dynamic surface tension measurement. The increased surface activity resulted in higher foamate flow rates. Furthermore, the effects could be correlated with secondary structure changes and with the dynamic surface pressure. The new result of this study is that the effect of the denaturation of a protein on foam fractionation depends on the protein concentration. At the lower feed concentration, effects became visible, which could not be observed at the higher concentration.
Assuntos
Fracionamento Químico/métodos , Lactoglobulinas/análise , Lactoglobulinas/química , Temperatura Alta , Lactoglobulinas/metabolismo , Desnaturação Proteica , Propriedades de SuperfícieRESUMO
The presence of both inversion (P) and time-reversal (T) symmetries in solids leads to a double degeneracy of the electronic bands (Kramers degeneracy). By lifting the degeneracy, spin textures manifest themselves in momentum space, as in topological insulators or in strong Rashba materials. The existence of spin textures with Kramers degeneracy, however, is difficult to observe directly. Here, we use quantum interference measurements to provide evidence for the existence of hidden entanglement between spin and momentum in the antiperovskite-type Dirac material Sr3SnO. We find robust weak antilocalization (WAL) independent of the position of EF. The observed WAL is fitted using a single interference channel at low doping, which implies that the different Dirac valleys are mixed by disorder. Notably, this mixing does not suppress WAL, suggesting contrasting interference physics compared to graphene. We identify scattering among axially spin-momentum locked states as a key process that leads to a spin-orbital entanglement.
RESUMO
The performance of the Centrifugal Partition Chromatography (CPC) as a liquid-liquid chromatographic technique depends strongly on the two-phase solvent system used. Thereby the individual influence of the retention of the stationary phase, the coalescence, and the dispersion of the mobile phase in the chambers must be understood to select appropriate solvent systems and reach high separation efficiencies. In this study, an optical measurement system was used to investigate the influence of the physical properties of the Arizona solvent systems on the stationary phase retention in descending mode. Therefore, physical properties like density, viscosity, and interfacial tension were measured as well as the stationary phase retention. Using dimensionless numbers, a correlation between the stationary phase retention and the influencing parameters could be determined. The correlation was validated using data from the literature. Additionally, the solvent systems were modified by additives to identify the validity of the correlation. It was proven that the dimensionless numbers Capillary number (Ca) and Morton number (Mo) can be used to predict the stationary phase retention of other liquid-liquid solvent systems as well as for different operating conditions.
Assuntos
Cromatografia Líquida , Solventes/química , Água/química , Centrifugação , ViscosidadeRESUMO
A general approach is described for the formation of tetrahydrothiepines using donor-acceptor cyclopropanes. Thiochalcones, functioning as sulfur-containing four-atom building blocks, were reacted in a Lewis acid catalyzed formal (4 + 3)-cycloaddition reaction with donor-acceptor cyclopropanes as three-atom building blocks. Under mild conditions various tetrahydrothiepines were synthesized in good yields in a stereospecific reaction with high functional group tolerance.
RESUMO
Aqueous Two-Phase Extraction is known to be a gentle separation technique for biochemical molecules where product partitioning is fast. However, the reason for the high mass transfer rates has not been investigated, yet. Many researchers claim that the low interfacial tension facilitates the formation of very small droplets and with it a large interfacial area causing a fast partitioning. However, an experimental evidence for this hypothesis has not been published yet. In this study, the mass transfer coefficients of two proteins, namely lysozyme and bromelain, were determined by providing a defined interfacial area for partitioning. Compared to low molecular weight solutes the mass transfer coefficient for the proteins investigated was small proving for the first time that the large interfacial area and not fast diffusion seems to be the reason for fast protein partitioning.
Assuntos
Proteínas/isolamento & purificação , Tensão Superficial , Bromelaínas/química , Difusão , Peso Molecular , Muramidase/química , Proteínas/química , Soluções/química , Água/químicaRESUMO
Recently the Centrifugal Partition Chromatography (CPC) device is investigated as a reactor for biocatalytic reactions, as it enables biocatalyst immobilization without solid support and continuous operation of biphasic reaction systems. However, a detailed determination of the enzymes behavior in the CPC reactor and comparison to a classical stirred tank reactor (STR) for biphasic enzyme catalysis is not shown yet. In this study, the performance of an enzymatic biphasic hydrolysis reaction using lipase from Candida rugosa is systematically evaluated using a STR. The results are compared to different experiments conducted in the CPC reactor and used to evaluate the reaction performance in each. The same characteristics and limitations were observed in STR and CPC. At all states the CPC provided a similar reaction performance. However, the reaction in the CPC runs faster into limitations and was not easily scalable due to complex effects of the flow pattern. Although the enzyme was immobilized successfully and the activity of the lipase was preserved during CPC operation optimizations are needed to make the CPC reactor more competitive. For instance, scaling up the chamber geometry seems to be mandatory to increase the reaction performance, which may promote this reactor concept as an alternative to common devices for continuous biphasic biocatalytic reactions.
Assuntos
Centrifugação/métodos , Cromatografia Líquida/métodos , Proteínas Fúngicas/química , Lipase/química , Reatores Biológicos , Candida/enzimologia , Catálise , Centrifugação/instrumentação , Enzimas Imobilizadas/química , HidróliseRESUMO
In addition to the selection or adjustment of phase systems to gain a suitable partition coefficient for the target molecule, the separation efficiency in centrifugal partition chromatography (CPC) is strongly influenced by the hydrodynamic interactions of the mobile and the stationary phase in the chambers. Thus, the hydrodynamic interactions must be investigated and understood in order to enhance a CPC separation run. Different hydrodynamic effects like mass transfer, back mixing and the non-ideal behavior of stationary phase, which cannot be determined directly, are known, but quantifying these effects and their influence on separation performance is barely achieved. In order to understand their influence, a physically detailed mathematical model of a CPC chamber was developed. The model includes a parameter representing the hydrodynamic effects mentioned above and is able to determine the parameters significance by fitting them to separation experiment data. The acquired knowledge is used to correlate the effects of the hydrodynamic influences on the separation performance and can be used to forecast hydrodynamic and separation behavior in a CPC device.
Assuntos
Cromatografia Líquida/métodos , Catecóis/análise , Catecóis/isolamento & purificação , Centrifugação , Cromatografia Líquida/instrumentação , Hidrodinâmica , Hidroquinonas/análise , Hidroquinonas/isolamento & purificação , Solventes/químicaRESUMO
For the production of bio active compounds, e.g., active enzymes or antibodies, a conserved purification process with a minimum loss of active compounds is necessary. In centrifugal partition chromatography (CPC), the separation effect is based on the different distribution of the components to be separated between two immiscible liquid phases. Thereby, one liquid phase is kept stationary in chambers by a centrifugal field and the mobile phase is pumped through via connecting ducts. Aqueous two phase systems (ATPS) are known to provide benign conditions for biochemical products and seem to be promising when used in CPC for purification tasks. However, it is not known if active biochemical compounds can "survive" the conditions in a CPC where strong shear forces can occur due to the two-phasic flow under centrifugal forces. Therefore, this aspect has been faced within this study by the separation of active laccases from a fermentation broth of Pleurotus sapidus. After selecting a suitable ATPS and operating conditions, the activity yield was calculated and the preservation of the active enzymes could be observed. Therefore, CPC could be shown as potentially suitable for the purification of bio-active compounds.
Assuntos
Cromatografia Líquida/métodos , Lacase/isolamento & purificação , Pleurotus/enzimologia , CentrifugaçãoRESUMO
Multi-phase reaction systems, mostly aqueous organic systems, are used in enzyme catalysis to convert hydrophobic substrates which are almost insoluble in aqueous media. In this study, a Centrifugal Partition Chromatograph is used as a compact device for enzymatic multi-phase reaction that combines efficient substrate supply to the aqueous phase and separation of both phases in one apparatus. A process design procedure to systematically select the aqueous and organic phase to achieve stable and efficient reaction rates and operation conditions in Centrifugal Partition Chromatography for efficient mixing and separation of the phases is presented. The procedure is applied to the hydrolysis of 4-nitrophenyl palmitate with a lipase derived from Candida rugosa. It was found that the hydrolysis rate of 4-nitrophenyl palmitate was two times higher in Centrifugal Partition Chromatography than in comparable stirred tank reactor experiments.
Assuntos
Proteínas Fúngicas/química , Lipase/química , Biocatálise , Reatores Biológicos , Candida/enzimologia , Distribuição Contracorrente , Hidrólise , Cinética , Palmitatos/química , Água/químicaRESUMO
In centrifugal partition chromatography (CPC) the separation efficiency is mainly influenced by the hydrodynamic of mobile and stationary phase in the chambers. Thus, the hydrodynamic has to be investigated and understood in order to enhance a CPC separation run. Different chamber geometries have been developed in the past and the influence of several phase systems and CPC operating conditions were investigated for these chambers. However, a direct comparison between the different chamber types has not been performed yet. In order to investigate the direct influence of the chamber design on the hydrodynamic, several chamber designs - partially similar in geometry to commercial available designs - are investigated under standardized conditions in the present study. The results show the influence of geometrical aspects of the chamber design on the hydrodynamic and therewith, on the separation efficiency. As a conclusion of the present study, some ideas for an optimal chamber design for laboratory and industrial purpose are proposed.
Assuntos
Distribuição Contracorrente/métodos , Centrifugação , Distribuição Contracorrente/instrumentação , HidrodinâmicaRESUMO
The experimentally measured input-output characteristics of optically pumped semiconductor microcavities exhibits unexpected oscillations modifying the fundamentally linear slope in the excitation power regime below lasing. A systematic microscopic analysis reproduces these oscillations, identifying them as a genuine quantum-memory effect, i.e., a photon-density correlation accumulated during the excitation. With the use of projected quantum measurements, it is shown that the input-output oscillations can be controlled and enhanced by an order of magnitude when the quantum fluctuations of the pump are adjusted.
RESUMO
Aqueous Two-Phase Extraction (ATPE) represents a promising unit operation for downstream processing of biotechnological products. The technique provides several advantages such as a biocompatible environment for the extraction of sensitive and biologically active compounds. However, the tendency of some aqueous two-phase systems to form intensive and stable emulsions can lead to long phase separation times causing an increased footprint for the required mixer-settler devices or the need for additional equipment such as centrifuges. In this work, a novel approach to improve ATPE for downstream processing applications called 'Tunable Aqueous Polymer-Phase Impregnated Resins' (TAPPIR(®))-Technology is presented. The technology is based on the immobilization of one aqueous phase inside the pores of a solid support. The second aqueous phase forms the bulk liquid around the impregnated solids. Due to the immobilization of one phase, phase emulsification and phase separation of ATPE are realized in a single step. In this study, a biodegradable and sustainable aqueous two-phase system consisting of aqueous polyethylene glycol/sodiumcitrate solutions was chosen. The impregnation of different macroporous glass and ceramic solids was investigated and could be proven to be stable. Additionally, the separation of the dye Patent blue V was successfully performed with the TAPPIR(®)-Technology. Thus, the "proof of principle" of this technology is presented.
Assuntos
Extração Líquido-Líquido/métodos , Polietilenoglicóis/química , Biotecnologia , Cinética , Água/químicaRESUMO
This study provides current data on key questions about retraction of scientific articles. Findings confirm that the rate of retractions remains low but is increasing. The most commonly cited reason for retraction was research error or inability to reproduce results; the rate from research misconduct is an underestimate, since some retractions necessitated by research misconduct were reported as being due to inability to reproduce. Retraction by parties other than authors is increasing, especially for research misconduct. Although retractions are on average occurring sooner after publication than in the past, citation analysis shows that they are not being recognised by subsequent users of the work. Findings suggest that editors and institutional officials are taking more responsibility for correcting the scientific record but that reasons published in the retraction notice are not always reliable. More aggressive means of notification to the scientific community appear to be necessary.
Assuntos
Pesquisa Biomédica/normas , Políticas Editoriais , Retratação de Publicação como Assunto , Autoria , Pesquisa Biomédica/ética , HumanosRESUMO
CONTEXT: The need to reinvigorate medical confidentiality protections is recognised as an important objective in building patient trust necessary for successful health outcomes. Little is known about patient understanding and expectations from medical confidentiality. OBJECTIVE: To identify and describe patient views of medical confidentiality and to assess provisionally the range of these views. DESIGN: Qualitative study using indepth, open ended face-to-face interviews. SETTING: Southeastern Pennsylvania and southern New Jersey, USA. PARTICIPANTS: A total of 85 women interviewed at two clinical sites and three community/research centres. MAIN OUTCOME MEASURES: Subjects' understanding of medical confidentiality, beliefs about the handling of confidential information and concerns influencing disclosure of information to doctors. RESULTS: The subjects defined medical confidentiality as the expectation that something done or said would be kept "private" but differed on what information was confidential and the basis and methods for protecting information. Some considered all medical information as confidential and thought confidentiality protections functioned to limit its circulation to medical uses and reimbursement needs. Others defined only sensitive or potentially stigmatising information as confidential. Many of these also defined medical confidentiality as a strict limit prohibiting information release, although some noted that specific permission or urgent need could override this limit. CONCLUSIONS: Patients share a basic understanding of confidentiality as protection of information, but some might have expectations that are likely not met by current practice nor anticipated by doctors. Doctors should recognise that patients might have their own medical confidentiality models. They should address divergences from current practice and provide support to those who face emotional or practical obstacles to self-revelation.
Assuntos
Atitude , Confidencialidade , Ética Clínica , Adulto , Coleta de Dados/ética , Feminino , Humanos , Entrevistas como Assunto , Relações Médico-Paciente , Estados UnidosRESUMO
Bridging the gap between gene discovery and our ability to use genetic information to benefit health requires population-based knowledge about the contribution of common gene variants and gene-environment interactions to the risk of disease. The risks and benefits associated with population-based research involving genetics, especially lower-penetrance gene variants, can differ in nature from those associated with family-based research. In response to the urgent need for appropriate guidelines, the Centers for Disease Control and Prevention formed a multidisciplinary group to develop an informed consent approach for integrating genetic variation into population-based research. The group used expert opinion and federal regulations, the National Bioethics Advisory Commission's report on research involving human biological materials, existing consent forms, and literature on informed consent to create suggested language for informed consent documents and a supplemental brochure. This language reflects the premise that the probability and magnitude of harm, as well as possible personal benefits, are directly related to the meaning of the results for the health of the participant and that appropriate disclosures and processes for obtaining consent should be based on an assessment at the outset of the likelihood that the results will generate information that could lead directly to an evidence-based intervention. This informed consent approach is proposed to promote discussion about how best to enable potential participants to make informed decisions about population-based research involving genetics and to suggest issues for consideration by research sponsors, institutional review boards, and investigators.
Assuntos
Pesquisa em Genética , Genética Médica/normas , Guias como Assunto , Consentimento Livre e Esclarecido , Pesquisa/normas , DNA/análise , Genética Médica/legislação & jurisprudência , Humanos , Idioma , Pesquisa/legislação & jurisprudência , Terminologia como Assunto , Estados UnidosRESUMO
A minimally invasive laser-induced injury model is described to study thrombus development in mice in vivo. The protocol involves focusing the beam of an argon-ion laser through a compound microscope on the vasculature of a mouse ear that is sufficiently thin such that blood flow can be visualized by intravital microscopy. Two distinct injury models have been established. The first involves direct laser illumination with a short, high-intensity pulse. In this case, thrombus formation is inhibited by the GPIIb/IIIa antagonist, G4120. However, the anticoagulants, hirulog, PPACK, and NapC2 have minimal effect. This indicates that thrombus development induced by this model mainly involves platelet interactions. The second model involves low-intensity laser illumination of mice injected with Rose Bengal dye to induce photochemical injury in the region of laser illumination. Thrombi generated by this latter procedure have a slower development and are inhibited by both anticoagulant and anti-platelet compounds.