Hydrodynamic Effects on Biofilm Development and Recombinant Protein Expression

Hydrodynamics play an important role in the rate of cell attachment and nutrient and oxygen transfer, which can affect biofilm development and the level of recombinant protein production. In the present study, the effects of different flow conditions on the development of Escherichia coli biofilms and the expression of a model recombinant protein (enhanced green fluorescent protein, eGFP) were examined. Planktonic and biofilm cells were grown at two different flow rates in a recirculating flow cell system for 7 days: 255 and 128 L h(-1) (corresponding to a Reynolds number of 4600 and 2300, respectively). The fluorometric analysis showed that the specific eGFP production was higher in biofilms than in planktonic cells under both hydrodynamic conditions (3-fold higher for 255 L h(-1) and 2-fold higher for 128 L h(-1)). In the biofilm cells, the percentage of eGFP-expressing cells was on average 52% higher at a flow rate of 255 L h(-1). Furthermore, a higher plasmid copy number (PCN) was obtained for the highest flow rate for both planktonic (244 PCN/cell versus 118 PCN/cell) and biofilm cells (43 PCN/cell versus 29 PCN/cell). The results suggested that higher flow velocities promoted eGFP expression in E. coli biofilms

IMPACT OF IRRIGATION ON YIELD AND ENERGY BALANCE OF THE PRODUCTION OF OIL AND CAKE OF TWO SUNFLOWER VARIETIES

The energy balance for the production of sunflower oil and cake was carried out during the agricultural and industrial stage phase, where it was considered a cold extraction by hydraulic pressing, with the plant location in a rural area with a radius of 30km range. Data on productivity was used in two varieties of sunflower (Helio 358 and Aguara 04) grown in different seasons (2007/2008, 2008/2009), under different irrigation levels. Data showed that irrigation resulted in an increase in productivity of both varieties, and the best response was observed for Aguara 04 variety. Moreover, the increased intensity of irrigation negatively affected the energy balance, reducing the ratio between energy produced and energy used in the production chain. The most significant inputs in the energy intake were fertilizer followed by diesel oil, when irrigation was not used for. When the irrigation technique was used, the most significant inputs, in order of representativeness, were: energy, fertilizer and equipment.3261048105

Divergent effects of liraglutide, exendin-4, and sitagliptin on beta-cell mass and indicators of pancreatitis in a mouse model of hyperglycaemia

AIMS:Glucagon-like peptide-1 (GLP-1) receptor agonists and dipeptidyl peptidase-4 (DPP4) inhibitors improve glucose tolerance by still incompletely understood mechanisms. Each class of antihyperglycemic drugs has also been proposed to increase pancreatitis risk. Here, we compare systematically the effects of two widely-used GLP-1 analogues, liraglutide and exendin-4, and the DPP4 inhibitor, sitagliptin, in the mouse. METHODS:C57BL6 mice were maintained for 131 days on a normal diet (ND) or a diet comprising 60% fat (HFD) before measurements of fasting blood glucose and insulin, and intraperitoneal glucose tolerance. Beta- and alpha- cell volume, and Reg3b immunoreactivity, were measured by immunohistochemical analysis of pancreatic slices. RESULTS:Whereas liraglutide (200 µg/kg) and exendin-4 (10 µg/kg) treatment reduced body weight and/or improved glucose tolerance, sitagliptin (10 mg/kg) was without effect on either parameter. Liraglutide caused a sharp reduction in beta-cell mass in both ND and HFD mice, whereas exendin-4 exerted no effect. By contrast, sitagliptin unmasked an action of high fat diet to increase beta-cell mass. Reg3B positive area was augmented by all three agents in normal chow-fed mice, whilst sitagliptin and exendin-4, but not liraglutide, affected this parameter in HFD animals. Correspondingly sitagliptin, but not the GLP-1 analogues, increased circulating amylase levels in ND and HFD mice. CONCLUSIONS:Liraglutide improves glucose tolerance in the mouse whilst exerting relatively modest effects on pancreatitis risk. Conversely, exendin-4 and sitagliptin, at doses which exert, respectively, minor or no effects on metabolic parameters, lead to signs of pancreatitis

Enzymatic degradation of starch thermoplastic blends using samples of different thickness

The material studied was a thermoplastic blend of corn starch with a poly(ethylene-vinyl alcohol) copolymer, SEVA-C. The influence of both the material’s exposed surface and enzyme concentration on degradation kinetics was studied. As α-amylase is present in the blood plasma, experiments were performed, varying the material thickness and the α-amylase between 50 and 100 units/l, at 37°C, lasting up to 90 days. Four different batches using SEVA-C and starch samples of different thickness were performed. The positive correlation between degradation rate and the exposed material surface was confirmed, since thin films with larger exposed surfaces were degraded faster than thick square plates having the same total mass. The degradation extent depends on the total amount of amorphous starch present in the formulation rather than on the amount of enzyme used and the minimum thickness to ensure maximum degradation was estimated to be close to 0.25 mm

A novel multivariate STeady-state index during general ANesthesia (STAN)

The assessment of the adequacy of general anesthesia for surgery, namely the nociception/anti-nociception balance, has received wide attention from the scientific community. Monitoring systems based on the frontal EEG/EMG, or autonomic state reactions (e.g. heart rate and blood pressure) have been developed aiming to objectively assess this balance. In this study a new multivariate indicator of patients' steady-state during anesthesia (STAN) is proposed, based on wavelet analysis of signals linked to noxious activation. A clinical protocol was designed to analyze precise noxious stimuli (laryngoscopy/intubation, tetanic, and incision), under three different analgesic doses; patients were randomized to receive either remifentanil 2.0, 3.0 or 4.0 ng/ml. ECG, PPG, BP, BIS, EMG and [Formula: see text] were continuously recorded. ECG, PPG and BP were processed to extract beat-to-beat information, and [Formula: see text] curve used to estimate the respiration rate. A combined steady-state index based on wavelet analysis of these variables, was applied and compared between the three study groups and stimuli (Wilcoxon signed ranks, Kruskal-Wallis and Mann-Whitney tests). Following institutional approval and signing the informed consent thirty four patients were enrolled in this study (3 excluded due to signal loss during data collection). The BIS index of the EEG, frontal EMG, heart rate, BP, and PPG wave amplitude changed in response to different noxious stimuli. Laryngoscopy/intubation was the stimulus with the more pronounced response [Formula: see text]. These variables were used in the construction of the combined index STAN; STAN responded adequately to noxious stimuli, with a more pronounced response to laryngoscopy/intubation (18.5-43.1 %, [Formula: see text]), and the attenuation provided by the analgesic, detecting steady-state periods in the different physiological signals analyzed (approximately 50 % of the total study time). A new multivariate approach for the assessment of the patient steady-state during general anesthesia was developed. The proposed wavelet based multivariate index responds adequately to different noxious stimuli, and attenuation provided by the analgesic in a dose-dependent manner for each stimulus analyzed in this study.The first author was supported by a scholarship from the Portuguese Foundation for Science and Technology (FCT SFRH/BD/35879/2007). The authors would also like to acknowledge the support of UISPA—System Integration and Process Automation Unit—Part of the LAETA (Associated Laboratory of Energy, Transports and Aeronautics) a I&D Unit of the Foundation for Science and Technology (FCT), Portugal. FCT support under project PEst-OE/EME/LA0022/2013.info:eu-repo/semantics/publishedVersio

Proton-Coupled Electron-Transfer Mechanism for the Radical Scavenging Activity of Cardiovascular Drug Dipyridamole

Dipyridamole (DIP) is a well-known pharmaceutical drug used as a coronary vasodilator and anti-platelet agent in clinics for treating several cardiovascular diseases. Primarily, the therapeutic effects of the drug are attributed to its antioxidant potency. In this research, we aim to declare the unknown antioxidant mechanism of DIP as well as its potent chain-breaking antioxidant activity in polar aqueous medium inside the cells, using different experimental methods and theoretical quantum calculations. Data demonstrated the higher antioxidant capacity of DIP against ROS and free radicals in polar cell's interior. DIP is capable of generating long living and noninvasive DIP• radicals in oxidant condition that leads to an effective “chain-breaking antioxidant” activity. Quantum computational data indicated that DIP antioxidant has more favorable ionization potential than trolox which means DIP has higher antioxidant activity. Also, data showed that the direct hydrogen-transfer is not a favorable process to construct DIP• because of high barrier energy, though electron-transfer process can more easily to produce DIP•+ with the lowest barrier energy. Altogether, the electron donating potency of DIP to reduce ferric ion, having the low anodic oxidation peak potential, producing long lived stable DIP• radicals and protecting myoblast cells from oxidation, proposed the excellent “chain-breaking antioxidant” potency via electron-transfer mechanism of this vasodilator DIP drug in polar aqueous medium

Heterogeneities in leishmania infantum infection : using skin parasite burdens to identify highly infectious dogs

Background: The relationships between heterogeneities in host infection and infectiousness (transmission to arthropod vectors) can provide important insights for disease management. Here, we quantify heterogeneities in Leishmania infantum parasite numbers in reservoir and non-reservoir host populations, and relate this to their infectiousness during natural infection. Tissue parasite number was evaluated as a potential surrogate marker of host transmission potential. Methods: Parasite numbers were measured by qPCR in bone marrow and ear skin biopsies of 82 dogs and 34 crab-eating foxes collected during a longitudinal study in Amazon Brazil, for which previous data was available on infectiousness (by xenodiagnosis) and severity of infection. Results: Parasite numbers were highly aggregated both between samples and between individuals. In dogs, total parasite abundance and relative numbers in ear skin compared to bone marrow increased with the duration and severity of infection. Infectiousness to the sandfly vector was associated with high parasite numbers; parasite number in skin was the best predictor of being infectious. Crab-eating foxes, which typically present asymptomatic infection and are non-infectious, had parasite numbers comparable to those of non-infectious dogs. Conclusions: Skin parasite number provides an indirect marker of infectiousness, and could allow targeted control particularly of highly infectious dogs

A Comparative Computer Simulation of Dendritic Morphology

Computational modeling of neuronal morphology is a powerful tool for understanding developmental processes and structure-function relationships. We present a multifaceted approach based on stochastic sampling of morphological measures from digital reconstructions of real cells. We examined how dendritic elongation, branching, and taper are controlled by three morphometric determinants: Branch Order, Radius, and Path Distance from the soma. Virtual dendrites were simulated starting from 3,715 neuronal trees reconstructed in 16 different laboratories, including morphological classes as diverse as spinal motoneurons and dentate granule cells. Several emergent morphometrics were used to compare real and virtual trees. Relating model parameters to Branch Order best constrained the number of terminations for most morphological classes, except pyramidal cell apical trees, which were better described by a dependence on Path Distance. In contrast, bifurcation asymmetry was best constrained by Radius for apical, but Path Distance for basal trees. All determinants showed similar performance in capturing total surface area, while surface area asymmetry was best determined by Path Distance. Grouping by other characteristics, such as size, asymmetry, arborizations, or animal species, showed smaller differences than observed between apical and basal, pointing to the biological importance of this separation. Hybrid models using combinations of the determinants confirmed these trends and allowed a detailed characterization of morphological relations. The differential findings between morphological groups suggest different underlying developmental mechanisms. By comparing the effects of several morphometric determinants on the simulation of different neuronal classes, this approach sheds light on possible growth mechanism variations responsible for the observed neuronal diversity