847 research outputs found
TEMPRANILLO is a regulator of juvenility in plants
Many plants are incapable of flowering in inductive daylengths during the early juvenile vegetative phase (JVP). Arabidopsis mutants with reduced expression of TEMPRANILLO (TEM), a repressor of FLOWERING LOCUS T (FT) had a shorter JVP than wild-type plants. Reciprocal changes in mRNA expression of TEM and FT were observed in both Arabidopsis and antirrhinum, which correlated with the length of the JVP. FT expression was induced just prior to the end of the JVP and levels of TEM1 mRNA declined rapidly at the time when FT mRNA levels were shown to increase. TEM orthologs were isolated from antirrhinum (AmTEM) and olive (OeTEM) and were expressed most highly during their juvenile phase. AmTEM functionally complemented AtTEM1 in the tem1 mutant and over-expression of AmTEM prolonged the JVP through repression of FT and CONSTANS (CO). We propose that TEM may have a general role in regulating JVP in herbaceous and woody species
Genetic Diversity of PCR-Positive, Culture-Negative and Culture-Positive Mycobacterium ulcerans Isolated from Buruli Ulcer Patients in Ghana.
Culture of Mycobacterium ulcerans from Buruli ulcer patients has very low sensitivity. Thus confirmation of M. ulcerans infection is primarily based on PCR directed against IS2404. In this study we compare the genotypes obtained by variable number of tandem repeat analysis of DNA from IS2404-PCR positive cultures with that obtained from IS2404 positive, culture-negative tissue. A significantly greater genetic heterogeneity was found among culture-negative samples compared with that found in cultured strains but a single genotype is over-represented in both sample sets. This study provides evidence that both the focal location of bacteria in a lesion as well as differences in the ability to culture a particular genotype may underlie the low sensitivity of culture. Though preliminary, data from this work also suggests that mycobacteria previously associated with fish disease (M. pseudoshottsii) may be pathogenic for humans
Modification of molecular conformation of spray-dried whey protein microparticles improving digestibility and release characteristics
This study reports on the preparation of riboflavin-loaded whey protein isolate (WPI) microparticles, using desolvation and then spray drying. Ethanol desolvation led to the exposure of embedded hydrophobic amino acids of WPI to riboflavin, facilitating the formation of riboflavin-WPI complexes. The extent of desolvation and cross-linking influenced the morphology of the spray-dried microparticles, while the moisture content of microparticles decreased with desolvation and increased with crosslinking. The modification of WPI conformation upon desolvation could be retained in the dry state via spray drying. The gastric resistance, release site and release characteristics of microparticles were readily adjusted by varying the ethanol and calcium ion contents from 0 to 50% v/v and from 0 to 2 mM, respectively. The sample prepared from 30% v/v ethanol without calcium crosslinking displayed rapid peptic digestion in less than 30 min. The samples from 30% v/v ethanol at 1 and 2 mM Ca 2+ exhibited excellent gastric resistance and intestinal release
The Role of Parvalbumin-positive Interneurons in Auditory Steady-State Response Deficits in Schizophrenia
© The Author(s) 2019. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.Despite an increasing body of evidence demonstrating subcellular alterations in parvalbumin-positive (PV+) interneurons in schizophrenia, their functional consequences remain elusive. Since PV+ interneurons are involved in the generation of fast cortical rhythms, these changes have been hypothesized to contribute to well-established alterations of beta and gamma range oscillations in patients suffering from schizophrenia. However, the precise role of these alterations and the role of different subtypes of PV+ interneurons is still unclear. Here we used a computational model of auditory steady-state response (ASSR) deficits in schizophrenia. We investigated the differential effects of decelerated synaptic dynamics, caused by subcellular alterations at two subtypes of PV+ interneurons: basket cells and chandelier cells. Our simulations suggest that subcellular alterations at basket cell synapses rather than chandelier cell synapses are the main contributor to these deficits. Particularly, basket cells might serve as target for innovative therapeutic interventions aiming at reversing the oscillatory deficits.Peer reviewe
Time scale based analysis of in-situ crystal formation in droplet undergoing rapid dehydration
The surface structure of crystalline particles affects the functionality of the particles in drug delivery. Prediction of the final structure of particles that crystallize easily within the spray drying process is of interests for many applications. A theoretical framework was developed for the prediction of crystal structure precipitating on the surface of the particle. This model was based on the dimensionless Damkohler number (Da), to be an indicator of final particle morphology. Timescales of evaporation and reaction were required for calculation of the Damkohler number. The modified evaporation time scale was estimated based on the time that is available for the crystal to precipitate after supersaturation. The reaction time scale was estimated based on the time scale for induction time. Mannitol was produced under different processing conditions in order to validate the theoretical model. Results showed for the high Damkohler numbers, the surface structure of the particle was rough, while smaller Damkohler numbers led to relatively smooth particle surfaces. Additionally, although the beta polymorph was dominant in all of the experiments, alpha polymorph was precipitated in the experiments with a large Damkohler number. The theoretical framework developed will be a useful predictive tool to guide the manipulation of particle crystallization in spray dryers
An accurate account of mass loss during cheese ripening described using the reaction engineering approach (REA)-based model
Cheese ripening is an important step in cheese making for modifying surface and curd properties. Due to physical, chemical and biological changes, mass loss usually occurs during the process. Although these changes are essential for developing the texture and flavour of cheese, mass loss decreases product yields. A reliable mathematical model is used to quantify mass loss during cheese ripening so that the processing conditions can be fine-tuned to achieve the desirable throughput. In this study, for the first time, the reaction engineering approach (REA)-based model is applied to model the cheese ripening. The study shows that the REA-based model is accurate to model cheese ripening of Camembert and French smear cheese. In addition, the REA is able to model the cheese ripening under time-varying environmental conditions. For this purpose, the equilibrium activation energy is evaluated according to the corresponding humidity and temperature in each period, while the same relative activation energy for ripening under constant environmental conditions is implemented. The REA is a simple yet effective approach to model the simultaneous heat and mass transfer process accompanied by chemical and biological reactions. Considering its effectiveness, the REA can be applied in industrial settings for predicting mass loss during cheese ripening
Characterisation of thermal and structural behaviour of lipid blends composed of fish oil and milkfat
The blend of fish oil with a high percentage of long chain poly-unsaturated fatty acids, and milkfat with a high percentage of saturated fatty acids, could potentially demonstrate desirable characteristics from both components, such as increased omega-3 fatty acids and melting point, as well as improved crystallization and oxidative stability. In this study, the effect of various milkfat concentrations on thermal properties and crystalline structure of these blends were analysed to understand parameters determining the overall characteristics of the blend. Blends with different ratios of fish oil: milkfat (9:1, 7:3, 5:5, 3:7, 1:9), as well as pure fish oil and pure milkfat, were investigated at different cooling conditions. The crystallization behaviour in all samples shifted to lower temperature ranges, by increasing the cooling rate from 1 to 32 °C/min. However, the changes in cooling rate did not have significant effect on the melting profile of the samples. Whereas changes in milkfat ratio affect both the crystallization and melting behaviour. New crystallization peaks were observed on DSC spectra between the range of −4 to −13 °C in the blends. Moreover, new melting peaks appeared in two ranges of −1 to −8 °C and 8–9 °C, in the blends. The crystallization and melting behaviour of the blends were similar to those of milkfat when >30% milkfat was used. This was further confirmed via XRD where milkfat demonstrated the dominant polymorphic behaviour. Regarding shape of the crystals, fractal dimension analysis showed a similarity between clusters in blends containing 50% milkfat or higher. Increasing the ratio of milkfat led to an increase in fractal dimension which indicates higher mass-spatial distribution of the crystal networks in the blends. The data showed that adding 30% or more milkfat to pure fish oil resulted in blends demonstrating similar characteristics to milkfat, including thermal, structural, and oxidative stability. This shows the potential of blending a high percentage of docosahexaenoic acid in milk fat to improve their overall stability
The role of the intermediate stage of drying on particle in-situ crystallization in spray dryers
In-situ crystallization of particles in spray drying has several advantages particularly for product quality modification in the pharmaceutical industry. This process was investigated in a counter current spray dryer using lactose as a model material by manipulation of the local humidity within the drying chamber. Sample collection and humidity injection at different location of the dryer were carried out to better understand the mechanism of particle formation and solidification which are essential components of in-situ crystallization. They revealed that particle formation can be delayed by local humidity elevation. Differential scanning calorimetry and XRD of the yields showed that humidity manipulation was capable to produce semi crystalline lactose of up to 90% crystallinity. The results confirmed that there is a critical period for crystallization such that extending this period would significantly increase the degree of crystallization. Comparison on different requirements of crystallization indicated that extending the time for nucleation and the growth at the critical period via humidity manipulation has the most significant effect on the in-situ crystallization process
Enhancing the stability of protein-polysaccharides emulsions via Maillard reaction for better oil encapsulation in spray-dried powders by pH adjustment
Lipid oxidation remains a major problem faced by the dairy industry. The bio-active ingredient (oil/milkfat) can be shielded by encapsulation within a secondary material. Emulsion stability is one of the main requirements for the production of oil/fat microcapsules with low levels of free surface fat and better encapsulation efficiency. This study focused on the use of sodium caseinate (NaCas)-lactose complex; conjugated via the Maillard reaction, as encapsulating materials, and investigated the effect of pH on the stability of protein-polysaccharide oil-in-water (O/W) emulsions. Subsequently, the properties of spray dried oil microcapsules, including encapsulation efficiency, insolubility, wettability, and microstructure, were analysed. The results demonstrated that better NaCas-lactose interactions were achieved at pH 11, with enhanced adsorption of the conjugates at the oil droplet particles and subsequently better emulsifying properties and stability. Additionally, a better oil entrapment (95.2 ± 3.7%) by the cross-linked protein and lactose was achieved when the pH of NaCas-lactose mixture was adjusted to 11 as compared to a pH of 7.5 (73.1 ± 2%). The outcome showed that it was possible to achieve stable microcapsules with oil loading as high as 80%, and with similar functional properties as those with 40% oil loading
Ezrin interacts with the SARS coronavirus spike protein and restrains infection at the entry stage
© 2012 Millet et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Background: Entry of Severe Acute Respiratory Syndrome coronavirus (SARS-CoV) and its envelope fusion with host cell membrane are controlled by a series of complex molecular mechanisms, largely dependent on the viral envelope glycoprotein Spike (S). There are still many unknowns on the implication of cellular factors that regulate the entry process. Methodology/Principal Findings: We performed a yeast two-hybrid screen using as bait the carboxy-terminal endodomain of S, which faces the cytosol during and after opening of the fusion pore at early stages of the virus life cycle. Here we show that the ezrin membrane-actin linker interacts with S endodomain through the F1 lobe of its FERM domain and that both the eight carboxy-terminal amino-acids and a membrane-proximal cysteine cluster of S endodomain are important for this interaction in vitro. Interestingly, we found that ezrin is present at the site of entry of S-pseudotyped lentiviral particles in Vero E6 cells. Targeting ezrin function by small interfering RNA increased S-mediated entry of pseudotyped particles in epithelial cells. Furthermore, deletion of the eight carboxy-terminal amino acids of S enhanced S-pseudotyped particles infection. Expression of the ezrin dominant negative FERM domain enhanced cell susceptibility to infection by SARS-CoV and S pseudotyped particles and potentiated S-dependent membrane fusion. Conclusions/Significance: Ezrin interacts with SARS-CoV S endodomain and limits virus entry and fusion. Our data present a novel mechanism involving a cellular factor in the regulation of S-dependent early events of infection.This work was supported by the Research Grant Council of Hong Kong (RGC#760208)and the RESPARI project of the International Network of Pasteur Institutes
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