Fish protein hydrolysates from gold carp (Carassius auratus): I. A study of hydrolysis parameters using response surface methodology

The combined effects of pH, temperature (T), substrate/buffer ratio (S:B) and enzyme concentration (E) on protein recovery from gold carp (Carassius auratus) processing waste with Flavourzyme^® were characterised. The effect of hydrolysis parameters on the degree of hydrolysis (DH) was described through response surface analysis (RSA) and the model obtained was defined as follows: DH = ?316.30 + 7.1T + 44.5pH + 0.292S:B + 0.27E ? 0.048T² ? 2.407pH² ? 0.002S:B² ? 0.307TxpH ? 0.002S:BxE. All regression coefficients were significant (α = 0.05). The model showed a good fit with the experimental data, since the R² of 0.923 indicated that 92.3% of the variability within the range of values studied could be explained by the model. The mathematical model presented a plateau region with a maximum DH (>26.6%) at the following critical values: pH = 5.9, T = 53 °C, S:B = 14.7% and E = 80 LAPU (leucine aminopeptidase units) g^?1. Electrophoretic (SDS‐PAGE) patterns showed a progressive reduction in molecular weight of the peptidic fractions from 10 min of hydrolysis onwards. By controlling the enzymatic process, it was possible to predict the molecular weight of the peptides obtained, in turn affecting the functional and nutritional properties of the peptidic fractions. Copyright © 2004 Society of Chemical Industry     

Effect of Gene Silencing of Translation Initiation Factors eIF(iso)4G and eIF(iso)4E on Sour Cherry Rootstock Resistance to Sharka Disease

Sharka disease, caused by the Plum pox virus (PPV), is one of the most harmful, quarantine viral diseases that affect stone fruit crops. The absence of natural resistance to the virus in stone fruits has become a decisive factor for the use of genetic transformation methods to obtain stable forms. The eIF(iso)4G and eIF(iso)4E genes encode translation initiation factors used in the PPV life cycle. In the presented study, the effect of silencing these genes using the RNA interference method on the resistance of sour cherry rootstock 146-2 plants (Prunus pumila L. x Prunus tomentosa Thunb) to the sharka disease was studied. Two vectors have been created for the genetic transformation of plants, with self-complementary sequences of the eIF(iso)4G and eIF(iso)4E gene fragments. The hairpin expression cassette contains a strong promoter of the peach ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCo) gene, as well as an intron and terminator of the same gene. We used the pMF1 vector containing recombinase R and a codA-nptII gene which makes it possible to obtain intragenic marker-free plants. A successful genetic transformation was carried out by the AGL0 strain of A. tumefaciens. Whole leaves of shoots cultivated in vitro were used as a source of explants. Eight independent transgenic lines of rootstock 146-2 were obtained in experiments (sixlines with a hairpin to the eIF(iso)4G gene and two lines with a hairpin to the eIF(iso)4E gene). Their status was confirmed by the PCR and Southern blotting. The obtained plants were acclimatized in a greenhouse. The silencing of the eIF(iso)4G and eIF(iso)4E genes in transgenic plants was confirmed by the quantitative PCR. The presence of specific small interfering (si) RNAs was confirmed by the method of Northern blotting. Plants of all transgenic rootstock lines were infected with PPV by the method of grafting with infected buds. Resistance to the PPV infection of the obtained transgenic plants was carried out by using an enzyme immunoassay. The ELISA results showed that silencing the eIF(iso)4G gene did not lead to increased resistance while silencing the eIF(iso)4E factor gene led to increased resistance to the PPV, and the one line’s plants showed no signs of infection for two years after infecting. The work demonstrates a (promising) approach in which the creation of stone cultures resistant to the plum pox virus can be achieved by suppressing the genes of translation initiation factors in clonal rootstocks.     

Hybrid Gold Nanorod-Based Nanoplatform with Chemo and Photothermal Activities for Bimodal Cancer Therapy

Metal nanoparticles (NPs), particularly gold nanorods (AuNRs), appear as excellent platforms not only to transport and deliver bioactive cargoes but also to provide additional therapeutic responses for diseased cells and tissues and/or to complement the action of the carried molecules. In this manner, here, we optimized a previous developed metal-based nanoplatform composed of an AuNR core surrounded by a polymeric shell constructed by means of the layer-by-layer approach, and in which very large amounts of the antineoplasic drug doxorubicin (DOXO) in a single loading step and targeting capability thanks to an outer hyaluronic acid layer were incorporated by means of an optimized fabrication process (PSS/DOXO/PLL/HA-coated AuNRs). The platform retained its nanometer size with a negative surface charge and was colloidally stable in a range of physiological conditions, in which only in some of them some particle clustering was noted with no precipitation. In addition, the dual stimuli-responsiveness of the designed nanoplatform to both endogenous proteases and external applied light stimuli allows to perfectly manipulate the chemodrug release rates and profiles to achieve suitable pharmacodynamics. It was observed that the inherent active targeting abilities of the nanoplatfom allow the achievement of specific cell toxicity in tumoral cervical HeLa cells, whilst healthy ones such as 3T3-Balb fibroblast remain safe and alive in agreement with the detected levels of internalization in each cell line. In addition, the bimodal action of simultaneous chemo- and photothermal bioactivity provided by the platform largely enhances the therapeutic outcomes. Finally, it was observed that our PSS/DOXO/PLL/HA-coated AuNRs induced cell mortality mainly through apoptosis in HeLa cells even in the presence of NIR light irradiation, which agrees with the idea of the chemo-activity of DOXO predominating over the photothermal effect to induce cell death, favoring an apoptotic pathway over necrosis for cell death.     

Gender, victimization, and outcomes: Reconceptualizing risk.

Large-scale studies of gender differences in psychopathological reactions to victimization have focused on posttraumatic stress disorder, overlooking other trauma-related disorders. The present study expands this literature with a contextualized examination of interpersonal aggression exposure and sequelae. Using k-means cluster analysis on a sample of 16,000, the authors identified 8 distinct profiles of exposure to sexual violence, physical assault, stalking, and emotional abuse. Analyses of covariance then suggested links among victimization profile, gender, and mental and physical health. Results revealed no meaningful interactive effects of gender and interpersonal aggression on outcomes, once lifetime exposure to aggressive events was adequately taken into account. These findings argue against theories of female victims' greater vulnerability to pathological outcomes, instead linking risk to exposure history. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effect of surface roughness on inactivation of Escherichia coli O157:H7 87-23 by new organic acid-surfactant combinations on alfalfa, broccoli, and radish seeds

Surface roughness has been reported as one of the factors affecting microbial attachment and removal. Seed surfaces are complex, and different seed varieties have different surface topographies. As a result, a sanitizer effective in eliminating pathogenic bacteria on one seed may not be as effective when applied to another seed. The objectives of this research were (i) to investigate the efficacy of malic acid and thiamine dilaurylsulfate (TDS) combined treatments for inactivation of E. coli O157:H7 strain 87-23 on alfalfa, broccoli, and radish seeds, (ii) to quantify surface roughness of the seeds, and (iii) to determine the correlation between microbial removal and surface roughness. The surface roughness of each seed type was measured by confocal laser scanning microscopy (CLSM) and surface profilometry. Surface roughness (Ra) values of the seeds were then calculated from CLSM data. Seeds inoculated with E. coli O157:H7 87-23 were washed for 20 min in malic acid and TDS solutions and rinsed for 10 min in tap water. Radish seeds had the highest Ra values, followed by broccoli and alfalfa seeds. A combination of 10% malic acid and 1% TDS was more effective than 20,000 ppm of Ca(OCl)(2) for inactivation of E. coli O157:H7 87-23 on broccoli seeds, while the inactivation on radish and alfalfa seeds was not significantly different compared with the 20,000-ppm Ca(OCl)(2) wash. Overall, a negative correlation existed between the seeds' Ra values and microbial removal. Different seeds had different surface roughness, contributing to discrepancies in the ability of the sanitizers to eliminate E. coli O157:H7 87-23 on the seeds. Therefore, the effectiveness of one sanitizer on one seed type should not be translated to all seed varieties.     

True Density Prediction of Garlic Slices Dehydrated by Convection

Physiochemical parameters with constant values are employed for the mass‐heat transfer modeling of the air drying process. However, structural properties are not constant under drying conditions. Empirical, semi‐theoretical, and theoretical models have been proposed to describe true density (ρ_p). These models only consider the ideal behavior and assume a linear relationship between ρ_p and moisture content (X); nevertheless, some materials exhibit a nonlinear behavior of ρ_p as a function of X with a tendency toward being concave‐down. This comportment, which can be observed in garlic and carrots, has been difficult to model mathematically. This work proposes a semi‐theoretical model for predicting ρ_p values, taking into account the concave‐down comportment that occurs at the end of the drying process. The model includes the ρ_s dependency on external conditions (air drying temperature (T_a)), the inside temperature of the garlic slices (T_i), and the moisture content (X) obtained from experimental data on the drying process. Calculations show that the dry solid density (ρ_s) is not a linear function of T_a, X, and T_i. An empirical correlation for ρ_s is proposed as a function of T_i and X. The adjustment equation for T_i is proposed as a function of T_a and X. The proposed model for ρ_p was validated using experimental data on the sliced garlic and was compared with theoretical and empirical models that are available in the scientific literature. Deviation between the experimental and predicted data was determined. An explanation of the nonlinear behavior of ρ_s and ρ_p in the function of X, taking into account second‐order phase changes, are then presented.     

Effect of Dipping and Vacuum Impregnation Pretreatments on the Quality of Frozen Apples: A Comparative Study on Organic and Conventional Fruits

The effect of dipping and vacuum impregnation (VI) pretreatments with lemon juice solution on the quality and stability of organic and conventional frozen apples was investigated. Fresh apples were characterized; organic apples showed, at equal starch and ripeness index, a lower sugar content, and higher acidity than conventional ones. The polyphenol content was slightly higher in organic apples than in conventional ones while polyphenoloxidase activity was similar. No differences in color and firmness were evidenced. Dipping affected organic and conventional apples’ color by determining an increase of lightness (ΔL^* ≈ 4) and h° (Δh° ≈ 6) parameters. VI reduced the lightness of apples (ΔL^* ≈ ?3) but the addition of lemon juice counterbalanced the lightness reduction by increasing ΔL^* from 3 to 1.5 ca. Pretreatments did not affect the firmness of organic fruits while impaired that of the conventional ones ( 26% on average), likely due to different fruit matrix porosity and cell wall composition. Freezing (?40 °C) and frozen storage (up to 300 days) dramatically reduced the firmness of organic (42%) and conventional products (58%). At equal pretreatment and storage time (that is, 15, 30, 300 days), higher firmness retention was evidenced in organic apples than in conventional ones. All through frozen storage, VI was shown to better preserve the mechanical properties of organic apples than that of conventional ones. Both freezing and frozen storage reduced the hue of frozen apple products by up to 8% due to browning reactions. Lemon juice addition increased the hue of both frozen samples and thawed samples by about 2% all through storage time.     

Casein‐Based Powders: Characteristics and Rehydration Properties

Casein‐based powders are gaining industrial interest due to their nutritional and functional properties, but they are also known to have poor rehydration abilities. The fundamental physical and chemical mechanisms involved in the rehydration of these powders are essential for determining the critical steps in the manufacturing processes and for developing casein powders with improved rehydration properties. A number of analytical methods have been developed to measure the rehydration ability of powders, but criteria for the selection of methods for casein‐based powders have not been provided. This review article provides an overview of the characteristics and methods for the production of casein‐based powders, methodologies to measure their rehydration properties, and it summarizes the current state of understanding regarding rehydration. Advancements have been made in the field; however, a fundamental understanding enabling improvement of the rehydration properties of these powders is still lacking.