3-Isobutyl-2-methoxypyrazine is neutrally perceived by consumers at usual concentrations in French Sauvignon and Fer wines from the Gaillac area

3-isobutyl-2-methoxypyrazine (IBMP) is a grape-derived aroma compound responsible for the bell pepper character of wine. It is still unclear whether this molecule is always negatively perceived by consumers. The objective of this study was to establish a consumer rejection threshold (CRT) for IBMP in French white and red wines from the Gaillac area made from Sauvignon and Fer respectively.The best estimate thresholds (BET) were determined by carrying out three-alternative forced choice (3-AFC) tests: 5.5 ng/L for Sauvignon and 16.8 ng/L for Fer. For the estimation of the CRT, consumers (n = 48) received pairs of samples consisting of a base wine and a base wine spiked with an ascending concentration of IBMP. They were asked to indicate which sample they preferred, and the CRT was calculated as the concentration for which the spiked sample was significantly rejected. CRTs were determined at 50 ng/L and 30 ng/L for Sauvignon and Fer respectively.Our findings indicate that IBMP is more acceptable in white wine than in red wine. As IBMP concentrations reported in the literature for Sauvignon and Fer are generally below CRT concentrations, IBMP appears to be neutrally perceived by consumers at usual concentrations in wines from Gaillac made from these two cultivars.Our findings tend to contradict the belief in the wine industry that consumers systematically reject ‘vegetative’ styles of wines, and do not encourage local winegrowers and winemakers to necessarily implement viticultural or enological practices to minimise IBMP concentrations in wine.

Optimasi dan Validasi Metode Penentuan Kadar Asam Glikolat dan Asam Laktat Dalam Krim Menggunakan Kromatografi Cair Kinerja Tinggi

<p>Telah dilakukan optimasi dan validasi metode penentuan asam glikolat dan asam laktat dalam krim menggunakan kromatografi cair kinerja tinggi. Pemisahan asam glikolat dan asam laktat dilakukan pada kolom fasa balik C-8menggunakan fasa gerak asam ortofosfat 0,1% dengan pH 3,5 dan detektor <em>UV-Visible</em>. Standar asam glikolat dan asam laktat dibuat dengan melarutkannya menggunakan asam ortofosfat 0,1% pH 3,5. Hasil eksperimen menunjukkan bahwa pada rentang konsentrasi 25 – 400 μg/mL, asam glikolat dan asam laktat memiliki kurva yang linear dengan koefisien korelasi masing-masing 0,9997 dan 0,9999. Uji presisi untuk larutan standar berkonsentrasi 100 µg/mL menghasilkan simpangan baku relatif sebesar 1,49% untuk asam glikolat dan 1,72% untuk asam laktat. Metode yang telah dioptimasi memberikan akurasi yang baik yang ditunjukkan oleh nilai perolehan kembali dari pengukuran tiga <em>spiked sample</em> dengan konsentrasi berbeda (50, 100, dan 150 μg/mL). Nilai perolehan kembali untuk masing-masing konsentrasi <em>spiked sample</em> adalah 97,12% ± 0,69; 98,76% ± 0,43; 100,80% ± 0,29 untuk asam glikolat dan 97,58% ± 0,39; 96,20% ± 0,68; 98,00% ± 0,38 untuk asam laktat. Batas deteksi dan batas kuantisasi untuk asam glikolat adalah 0,05 dan 0,17 μg/mL, sedangkan untuk asam laktat adalah 1,40 dan 4,67 μg/mL. Nilai kekasaran metode untuk asam glikolat pada hari pertama dan hari kedua adalah 1,43% dan 1,67%, sedangkan untuk asam laktat adalah 1,67% dan 1,25%. Metode yang telah dioptimasi dan divalidasi berpotensi untuk digunakan secara spesifik pada penentuan kadar asam glikolat dan asam laktat dalam krim.</p><p><strong>Optimization and Validation of Determination Methods of Glycolic Acid and Lactic Acid in Cream Using High-Performance Liquid Chromatography.</strong> A high-performance liquid chromatography analytical method for the determination of glycolic acid and lactic acid in creams has been optimized and validated. The separation was performed in a reverse phase C–8 column with a mobile phase of 0.1%, orthophosphoric acid at pH 3.5, and UV-Visible detector. The standard of glycolic acid and lactic acid was dissolved in 0.1% orthophosphoric acid at pH 3.5. The experimental results showed that in the concentration range of 25–400 μg/mL, glycolic acid and lactic acid showed a linear curve with a correlation coefficient of 0.9997 and 0.9999, respectively. The precision test for standard solutions containing 100 µg/mL resulted in a relative standard deviation of 1.49% for glycolic acid and 1.72% for lactic acid. The optimized method provided good accuracy indicated by the recovery of the measurement of three spiked samples in different concentrations (50, 100, and 150 μg/mL). The recovery for each concentration of the spiked sample was 97.12% ± 0.69; 98.76% ± 0.43; 100.80% ± 0.29 for glycolic acid and 97.58% ± 0.39; 96.20% ± 0.68; 98.00% ± 0.38 for lactic acid. The limit of detection and limit of quantization for glycolic acid was 0.05 and 0.17 μg/mL, and for lactic acid was 1.40 and 4.67 μg/mL. The ruggedness of the method for glycolic acid on the first day and second day was 1.43% and 1.67%, while for lactic acid, it was 1.67% and 1.25%. The method that has been optimized and validated shows the potential to be used specifically for the determination of glycolic acid and lactic acid in the cream.</p>

Spiked sample covariance matrices with possibly multiple bulk components

In this paper, we study the convergent limits and rates of the eigenvalues and eigenvectors for spiked sample covariance matrices whose spectrum can have multiple bulk components. Our model is an extension of Johnstone’s spiked covariance matrix model. Based on our results, we can extend many statistical applications based on Johnstone’s spiked covariance matrix model.

Combinatorial Antimicrobicidal Peptides Exhibit Enhanced Activity Against Bacterial Contaminants In Stored Platelet Concentrates (PCs).

Abstract 1124 Introduction: Contamination of blood and blood components by bacteria, virus, fungi and parasites is a major safety risk in transfusion medicine. Novel proof-of-concepts for microbial reduction that enhance risk-to-benefit ratio of the treated products are still an unmet public health need in transfusion medicine. We have recently shown that synthetic antimicrobicidal peptides (AMPs) originating from thrombin-induced human platelet-derived antimicrobial proteins (named PD1-PD4) and repeats of Arginine-Tryptophan (RW1-RW5), demonstrate microbicidal activity against bacteria in plasma and PCs. In the present study we selected RW2, RW3 and RW4 and tested the effect of the peptides individually and in various combinations (cocktail) to see whether the cocktail approach enhances the antimicrobicidal activity of these peptides. Methods: The RW2, RW3 and RW4 peptides were tested on platelet samples spiked with 104 colony forming units (cfu) of Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa. Each spiked sample was incubated individually with 10 mM of RW2, RW3, and RW4 peptides for 1 hour at 37°C to observe their individual effect. Peptides were then combined in the following way to assess their cocktail effect: RW2+RW3; RW2+RW4; RW3+RW4; RW2+RW3+RW4. Spiked sample without any peptide was included as control. Following incubation with the peptide a ten-fold dilution of the inoculum was made and a fixed volume plated on nutrient agar plates. The plates were incubated at 37°C for 18–24 hours and colonies were counted and expressed as cfu/ml. Results: Our analysis revealed that individual peptides RW2, RW3 and RW4 were either ineffective or were moderately microbicidal (100-fold reduction) against S. aureus, S. epidermidis and P. aeruginosa. However, in combination (cocktail), these peptides together demonstrated enhanced microbicidal activity against bacteria in spiked platelets. The combinations, RW2+RW4, RW3+RW4 and RW2+RW3+RW4 were the most effective that resulted in 1000-fold reduction of all three bacteria tested. Conclusion: The present study conclusively demonstrates the synergistic effect of antimicrobicidal peptides whose combined microbicidal activity is 1000-fold higher than when the peptide is acting alone. By selecting appropriate combination of AMPs against specific bacteria of interest, new proof-of-concepts could be developed that are alternatives to the current pathogen reduction agents. The findings and conclusions in this abstract have not been formally disseminated by the Food and Drug Administration and should not be construed to represent any Agency determination or policy. Disclosures: No relevant conflicts of interest to declare.

Activated Platelet-Derived Antimicrobial Peptides Exhibit Virucidal Properties against Vaccinia Virus in Plasma.

Abstract 2118 Poster Board II-95 Introduction: Contamination of blood and blood components by bacteria, virus, fungi and parasites is a major safety risk in transfusion medicine. While there has been a tremendous success in inactivating virus contamination in blood products through UV-irradiation, new and novel proof-of-concepts for microbial reduction that enhance risk to benefit ratio of the treated products are still a public health need in transfusion medicine. In the present study, we tested four novel synthetic antimicrobial peptides originating from thrombin-induced human platelet-derived antimicrobial proteins named PD1-PD4 against an enveloped virus, Vaccinia Virus (VV) spiked in plasma as a model system. We have recently shown these peptides to be useful in reducing bacterial burden in plasma and platelets. These short synthetic peptides are human platelet-derived and known to cause no immune response in humans and non-hemolytic in nature as reported by others. Methods: The PD1-PD4 peptides were tested on plasma samples spiked with 10-fold dilutions of the wild-type lab strain of Vaccinia Virus (WR strain). Each spiked sample was pre-incubated individually with a peptide (PD1-PD4) for 1 hour at 37°C. Spiked sample without any peptide was included as control. A cell culture-based standard plaque reduction assay method was utilized to monitor the virucidal effectiveness of the peptides. Minimal inhibitory concentration of the peptides was also estimated by testing the peptides at doubling dilutions of 100 μg/ml, 50 μg/ml, 25 μg/ml and 12.5 μg/ml concentrations. Results: Our analysis revealed that peptides PD3 and PD4 were potent against vaccinia virus resulting in reduction of viral titers in the plasma. PD3 peptide demonstrated the highest virucidal activity by bringing about a 2-log reduction of VV titers. PD4 peptide treatment resulted in a 1-1.5 log reduction in viral titers. The minimal inhibitory concentration analysis revealed that at 50 μg/ml concentration both the PD3 and PD4 were able to bring about a log reduction in viral titers. Conclusion: The present study reports a novel antiviral agent for reducing vaccinia virus contamination in plasma. Safety profiles of these peptides as reported by others in conjunction with our current studies, provide a new proof-of-concept that could be useful as safer and simpler alternatives to the viral reduction agents in transfusion medicine. The findings and conclusions in this abstract have not been formally disseminated by the Food and Drug Administration and should not be construed to represent any Agency determination or policy. Disclosures: No relevant conflicts of interest to declare.

Novel Antimicrobial Peptide-Based Blood Safety Strategies for Bacterial Reduction

Bacterial contamination of blood and blood components is a major safety concern in transfusion medicine. In order to facilitate safer transfusion products to the end users, there is a critical need for novel proof-of-concept ideas for pathogen reduction, which are different from the current ones that outweigh the associated toxicity and/or contamination risk. Present study involves use of nine novel synthetic antimicrobial peptides (four originated from thrombin-induced human platelet derived antimicrobial proteins named PP1-PP4 and five having 1–5 repeats of arginine and tryptophan residues, named DP1-DP5. These peptides were tested on plasma samples spiked with 10-fold dilutions of 5 different bacteria (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Bacillus cereus) that are important to the field of transfusion medicine and analyzed whether these spiked plasma samples could be cured of the pathogens. Each spiked sample was incubated with a peptide (PP1-PP4 and DP1-DP5) for 2 hours at 37°C. Following incubation, a fixed volume of the inoculum was plated on nutrient agar plates and incubated overnight at 37°C for colony count. Spiked sample without any peptide was included as control. Results revealed that out of nine peptides tested, while DP3 and DP4 were active against all 5 organisms tested resulting in 50–100 % of inhibition of specific organisms, peptide PP4 was only active against E. coli, P. aeruginosa and Bacillus cereus resulting in a 30–100% reduction in the CFU/ml compared to the controls. Table 1 Organism Colony count expressed in % Control PP1 PP2 PP3 PP4 DP1 DP2 DP3 DP4 DP5 S. aureus 100 90 100 26 100 100 20 10 56 100 E. coli 100 95 100 100 71 100 93 4 18 85 P. aeruginosa 100 100 100 100 0 100 0 0 13 100 K. pneumoniae 100 100 100 100 100 74 3 0 0 25 B. cereus 100 100 100 100 50 100 100 25 77 100 Based on these results, it appears that peptides used in this study provide a new antibacterial strategy against a range of bacteria and with further studies and refinement, these peptides could prove useful towards bacterial reduction in blood and blood products. The findings and conclusions in this abstract have not been formally disseminated by the Food and Drug Administration and should not be construed to represent any Agency determination or policy.