83 research outputs found
Proteomic analysis of the metabolic adaptation of the biocontrol agent Pseudozyma flocculosa leading to glycolipid production
The yeast-like epiphytic fungus Pseudozyma flocculosa is known to antagonize powdery mildew fungi through proliferation on colonies presumably preceded by the release of an antifungal glycolipid (flocculosin). In culture conditions, P. flocculosa can be induced to produce or not flocculosin through manipulation of the culture medium nutrients. In order to characterize and understand the metabolic changes in P. flocculosa linked to glycolipid production, we conducted a 2-DE proteomic analysis and compared the proteomic profile of P. flocculosa growing under conditions favoring the development of the fungus (control) or conducive to flocculosin synthesis (stress). A large number of protein spots (771) were detected in protein extracts of the control treatment compared to only 435 matched protein spots in extracts of the stress cultures, which clearly suggests an important metabolic reorganization in slow-growing cells producing flocculosin. From the latter treatment, we were able to identify 21 protein spots that were either specific to the treatment or up-regulated significantly (2-fold increase). All of them were identified based on similarity between predicted ORF of the newly sequenced genome of P. flocculosa with Ustilago maydis' available annotated sequences. These proteins were associated with the carbon and fatty acid metabolism, and also with the filamentous change of the fungus leading to flocculosin production. This first look into the proteome of P. flocculosa suggests that flocculosin synthesis is elicited in response to specific stress or limiting conditions
A deformation based blank design method for formed parts
peer reviewedBlank design is an important task in sheet metal forming process optimization. The initial blank shape has direct effect on the part quality. This paper presents a deformation based blank design approach to determine the initial blank shape for a formed part. The blank design approach is integrated separately into ABAQUS, and DD3IMP, a research purpose in-house FEA code, to demonstrate its compatibility with any FEA code. The algorithm uses FE results to optimize the blank shape for a part. Deep drawing simulation of a rectangular cup geometry was carried out with an initial blank shape determined empirically. The blank shape was iteratively modified, based on the deformation history, until an optimal blank shape for the part is achieved. The optimal blank shapes predicted by the algorithm using both FEA softwares were similar. Marginal differences in the shape error indicate that the deformation history based push/pull technique can effectively determine an optimal blank shape for a part with any FEA software. For the shape error selected, both procedures estimate the optimal blank shape for the part within five iterations
Phenolic Compounds and Skin Permeability: An In Silico Investigation
Background: The skin is the largest organ of the body and provides the main barrier between the internal and external environment. Assessment of skin permeability is of critical importance for understanding and predicting in vivo efficacy and bioavailability of bioactive phenolic compounds.
Objectives: This study investigated the relationship between skin permeability and phenolic compounds using in silico methods.
Methods: Screening of skin permeability was performed on 475 randomly selected phenolic compounds. Molecules were expressed in SMILE format downloaded from Phenol-Explorer Database (version 3.6, 2016). Then, their skin permeability was determined by the linear model of the quantitative structure-activity relationship (QSAR). The obtained results were investigated for normal distribution and correlation with pharmacological properties.
Results: Our investigation showed that ferulate hydroxycinnamic acid derivatives were the most important phenolic subclass with a permeability of -1.65 cm/s. The relationship between permeability and lipophilicity, water solubility, synthetic accessibility, and bioavailability was evaluated. The statistical analysis revealed that the highest skin permeability was associated with three parameters: the topological polar surface area (TPSA), molecular weight, and lipophilicity (iLog P).
Conclusion: The cutaneous permeability depended on several chemical parameters of the molecule used. The classification of phenolic compounds according to their structures proved a wide variability in this permeability
Patulin and patulin producing Penicillium spp. occurrence in apples and apple-based products including baby food
Introduction: Patulin has raised the international attention because of its health risk. In fact, it has mutagenic, neurotoxic, immunotoxic, genotoxic and gastrointestinal effects in animals. In the present work, patulin and patulin-producing Penicillium spp. in apple and apple-based products marketed in Qatar were analysed.
Methodology: Sampling was carried out using apple fruits and apple-based products. Fungi were isolated from undamaged apples, apple juice and baby apple food. DNA extraction was carried out with DNeasy Plant Mini Kit (QIAGEN, Valencia, USA). The molecular identification of fungal isolates was carried out using ITS1-ITS4 PCR. PCR products were sequenced and blasted. Patulin was extracted and analyzed by LC/MS/MS, then quantified using Agilent 1290UHPLC coupled to 6460 triple quadruple mass spectrometer.
Results: Forty-five samples of undamaged fresh apple fruits, apple juice and apple-based baby food products sold in different markets in Qatar were surveyed for both fungal and patulin contamination using Liquid Chromatography Tandem Mass Spectrometery (LC/MS/MS). Twenty-five Penicillium spp. isolates were selected, including 23 P. expansum and one isolate each of P. brevicompactum and P. commune. All the tested Penicillium spp. isolates produced patulin in vitro (from 40 to 100 μg/g on Malt Yeast Extract agar medium). Patulin was detected in 100% of apple juice samples at levels ranging from 5.27 to 82.21 μg/kg. Only 5 samples contained patulin levels higher than European Union recommended limit (50 μg/kg). The average patulin contamination was 30.67 μg/kg and 10.92 μg/kg in baby apple juice and in baby apple compote, respectively.This publication was made possible by NPRP grant # NPRP 4-259-2-083 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors
Effects of 8-Week In-Season Contrast Strength Training Program on Measures of Athletic Performance and Lower-Limb Asymmetry in Male Youth Volleyball Players
Strength training using high and lower load such as contrast training (CST) seems to be beneficial as it addresses larger adaptive reserves in youth athletes. Therefore, the aim of this study was to investigate the effects of CST on dynamic balance (composite score during dynamic balance test (CS-YBT)), one repetition maximum lower-limb back squat (1RM), jumping performance (single-leg hop (SLH) or countermovement jump height (CMJ)), lower-limb asymmetry (predicted from the single-leg jump performance between two legs [ILA]) in elite youth male volleyball players. Thirty-one male youth volleyball players aged 14 years were randomly assigned to a CST group (n = 16) or a control group (n = 15). The tests were performed before and after 8 weeks of training. Significant group × time interactions was observed for CS-YBT [p < 0.001, η(p)(2) = 0.70], 1RM [p < 0.001, η(p)(2) = 0.95], SLH with right and left leg [p < 0.001, η(p)(2) = 0.69 and 0.51], CMJ [p < 0.001, η(p)(2) = 0.47]), whilst it was not notable in ILA [p < 0.294]. Post hoc tests showed that CST group demonstrated greater improvement in all of the dependent variables from medium to large effect size (for all p < 0.001). As a result, 8 weeks of CST twice a week can be an effective and efficient training along with volleyball training to improve skill-related fitness measures, except for lower-limb asymmetry in young volleyball players
Identification of two novel hepatitis C virus subtype 2 from Tunisia (2v and 2w)
Background
Hepatitis C virus (HCV) has a high genetic diversity. Eight genotypes and 90 subtypes are currently described. Genotypes are clinically significant for therapeutic management and their determination is necessary for epidemiological studies.
Methods
Tunisian patients plasma samples (n = 6) with unassigned HCV-2 subtype using partial sequencing in the NS5B and Core/E1 regions were analyzed by realizing whole-genome sequencing analysis. Phylogenetic analyses were performed to assign subtypes.
Results
Phylogenetic analysis of the full genome sequences of Tunisian strains shows two subtypes within HCV-2. These later were genetically distinct from all previously established HCV-2 subtypes with nucleotide divergence greater than 15% (20% -31%). These two subtypes are proposed as new subtypes 2v and 2w.
Conclusions
The discovery of two new HCV-2 subtypes circulating in the Tunisian population confirms the great diversity of HCV-2 viruses and increases the total number of HCV-2 subtypes from 21 to 23.Peer Reviewe
Acute Effects of Different Plyometric and Strength Exercises on Balance Performance in Youth Weightlifters
Background: High-intensity muscle actions have the potential to temporarily improve the performance which has been denoted as postactivation performance enhancement. Objectives: This study determined the acute effects of different stretch-shortening (fast vs. low) and strength (dynamic vs. isometric) exercises executed during one training session on subsequent balance performance in youth weightlifters. Materials and Methods: Sixteen male and female young weightlifters, aged 11.3±0.6years, performed four strength exercise conditions in randomized order, including dynamic strength (DYN; 3 sets of 3 repetitions of 10 RM) and isometric strength exercises (ISOM; 3 sets of maintaining 3s of 10 RM of back-squat), as well as fast (FSSC; 3 sets of 3 repetitions of 20-cm drop-jumps) and slow (SSSC; 3 sets of 3 hurdle jumps over a 20-cm obstacle) stretch-shortening cycle protocols. Balance performance was tested before and after each of the four exercise conditions in bipedal stance on an unstable surface (i.e., BOSU ball with flat side facing up) using two dependent variables, i.e., center of pressure surface area (CoP SA) and velocity (CoP V). Results: There was a significant effect of time on CoP SA and CoP V [F(1,60)=54.37, d=1.88, p<0.0001; F(1,60)=9.07, d=0.77, p=0.003]. In addition, a statistically significant effect of condition on CoP SA and CoP V [F(3,60)=11.81, d=1.53, p<0.0001; F(3,60)=7.36, d=1.21, p=0.0003] was observed. Statistically significant condition-by-time interactions were found for the balance parameters CoP SA (p<0.003, d=0.54) and CoP V (p<0.002, d=0.70). Specific to contrast analysis, all specified hypotheses were tested and demonstrated that FSSC yielded significantly greater improvements than all other conditions in CoP SA and CoP V [p<0.0001 (d=1.55); p=0.0004 (d=1.19), respectively]. In addition, FSSC yielded significantly greater improvements compared with the two conditions for both balance parameters [p<0.0001 (d=2.03); p<0.0001 (d=1.45)]. Conclusion: Fast stretch-shortening cycle exercises appear to be more effective to improve short-term balance performance in young weightlifters. Due to the importance of balance for overall competitive achievement in weightlifting, it is recommended that young weightlifters implement dynamic plyometric exercises in the fast stretch-shortening cycle during the warm-up to improve their balance performance
Synergistic Effect of Cloves (Syzygium aromaticum), Thyme (Thymus vulgaris) and Lemon (Citrus limon) Blended Essential Oils Optimized by Mixture Design for Improving the Antioxidant Activity
Background: Combining various essential oils (EOs) for developing pharmaceutical formulations has been the focus of attention in recent years.
Objectives: This study aimed to determine the antioxidant effect of the combination of three Eos obtained from clove (Syzygium aromaticum L.), lemon peel (Citrus limon L.), and thyme (Thymus vulgaris L.) by using mixture design.
Methods: The EOs of lemon peel (EOL), clove (EOC), and thyme (EOT) as well as their combination were analyzed using a gas chromatograph with flame ionization detector (GC/FID). The antioxidant activities of the EOs from EOL, EOC, and EOT as well as their combination were measured adopting DPPH assay. The construction and statistical analysis of the experiment were designed using the NemrodW (LPRAI, version 2000) software.
Results: EOL, EOC, and EOT were found capable of neutralizing DPPH radical. EOC was distinguished by its strongest antiradical activity with IC50=15.02±0.02 µg/mL. EOT had an IC50=29.20±0.12 µg/mL while EOL had 188.69±0.95 µg/mL. The positive standard BHT was detected to be IC50=24±0.02 µg/ mL. The optimal, combinative mixture of essential oils may have been determined based on these isoresponse curves which allowed fixing the ideal combinations of ingredient in terms of quantity to obtain an EO mixture possessing appreciable and optimal antioxidant characteristics. The predicted antioxidant properties determined by the mixing plan model were retained and the experiments were carried out respecting the contents of proposed ingredients of 25.7% EOT, 32.3% EOL, and 41.9% EOC equivalent to 15.42 mg, 19.38 mg and 25.14 mg, respectively. This resulted in arriving at an essential oil mixture with an experimental IC50=11.023±0.145 µg/mL which was similar to those of the predicted antioxidant properties with an order of 10.907±0.212 µg/mL and a non-significant difference of P<0.05, based on which the validity of the proposed mixing plan model was determined. The combined EO was also found to be rich in eugenol (32.35±1.13%), thymol (25.49±0.03%), and limonene (21.30±0.02%).
Conclusion: Statistical planning and the development of utility profiles for mixtures of essential oils may have been used to predict the optimal composition as well as to determine their antioxidant profile
Do Acute Bouts of Resistance Training Influence the Psychometric Status and Affective State of Prepubertal Weightlifters?
Resistance training (RT) can represent a challenging and stressful endeavour for those who participate in it. We aimed to investigate the acute effect of four types of RT exercise [i.e., Concentric (CONC), Isometric (ISOM), Dynamic (DYN) and Eccentric (ECC)] on psychological parameters (feeling scale: FS) and perceived internal load (RPE) in young elite weightlifters. The RT protocols were differentiated according to the contractile characteristics of the involved muscles and comprised: (i) CONC: 3 sets of 3 hurdle jumps; (ii) ECC: 3 sets of drop jumps; (iii) ISOM: 3 sets of 3-second maximal isometric back squat; (iv) DYN: 3 sets of 3 repetitions of 10 RM maximal back squats. Thereafter, participants were reported scores for RPE and FS. The execution of different types of RT exercises did not induce changes in FS. On the contrary, differences in RPE were observed with the CONC protocol being the least acutely strenuous, followed by the ECC and DYN methods. Of all four types used in this study, ISOM seemed to induce the highest RPE score , though these remained relatively low across the 10-point scale. Coaches can manipulate training activities based on the condition of the athlete and the potential physical strain that is associated with each exercise type
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