Conus barbieri Raybaudi Massilia, 1995

Catálogo do Museo de Historia Natural USC. n. inventario 10009

Conus korni G. Raybaudi Massilia, 1993

Catálogo do Museo de Historia Natural USC. n. inventario 10012

Eugenol and carvacrol migration from PHBV films and antibacterial action in different food matrices

[EN] The antibacterial effect of PHBV films with oregano or clove essential oil, or their main compounds, carvacrol (CA) and eugenol (EU), respectively, was analysed in food matrices (cheese, chicken breast and pumpkin and melon) and in vitro test for Escherichia coli and Listeria innocua. The migration of CA and EU in the different food matrices was determined to analyse the food matrix effect on the film¿s antimicrobial effectiveness. The antimicrobial activity in foods was less remarkable than in in vitro test. Despite the antilisterial effect in the in vitro test, this was not noticed in any food matrix. The most significant antibacterial effects against E. coli were observed in cheese and pumpkin, whereas the highest migration of both CA and UE took place in melon. This lack of correlation reflected that many compositional factors affect the active compound¿s availability to exert its antibacterial action in a specific food.The authors thank the Ministerio de Economía y Competitividad (Spain) for the financial support provided through Project AGL2016-76699-R. Author Raquel Requena thanks the Ministry of Education, Culture and Sport (Spain) for the FPU (FPU13/03444) Grant.Requena-Peris, R.; Vargas, M.; Chiralt A. (2019). Eugenol and carvacrol migration from PHBV films and antibacterial action in different food matrices. Food Chemistry. 277:38-45. https://doi.org/10.1016/j.foodchem.2018.10.093S384527

Cupricyclins, Novel Redox-Active Metallopeptides Based on Conotoxins Scaffold

Highly stable natural scaffolds which tolerate multiple amino acid substitutions represent the ideal starting point for the application of rational redesign strategies to develop new catalysts of potential biomedical and biotechnological interest. The knottins family of disulphide-constrained peptides display the desired characteristics, being highly stable and characterized by hypervariability of the inter-cysteine loops. The potential of knottins as scaffolds for the design of novel copper-based biocatalysts has been tested by engineering a metal binding site on two different variants of an ω-conotoxin, a neurotoxic peptide belonging to the knottins family. The binding site has been designed by computational modelling and the redesigned peptides have been synthesized and characterized by optical, fluorescence, electron spin resonance and nuclear magnetic resonance spectroscopy. The novel peptides, named Cupricyclin-1 and -2, bind one Cu2+ ion per molecule with nanomolar affinity. Cupricyclins display redox activity and catalyze the dismutation of superoxide anions with an activity comparable to that of non-peptidic superoxide dismutase mimics. We thus propose knottins as a novel scaffold for the design of catalytically-active mini metalloproteins

Use of flow cytometry and total viable count to determine the effects of orange juice composition on the physiology of Escherichia coli

Orange juice (OJ) contains numerous compounds some of which are known to play key roles in growth and survival of bacteria. This study aimed to investigate the effects of natural or processing‐induced variations in OJ composition on the physiology of Escherichia coli. OJ and model OJ (MOJ) samples containing various sugars, organic acids, amino acids, or ascorbic acid were inoculated with E. coli K‐12 MG1655 in different growth phases. The culturability, viability, and physiology of the cells were investigated during storage using plate counting and flow cytometry. Generally, stationary‐phase cells displayed the greatest survival in both MOJ and OJ. Increase in incubation temperature from 4 to 22.5ºC caused a significant decrease in both healthy and culturable cell populations. Supplementation of MOJ with ascorbic acid and amino acids increased both the viability and culturability of the cells. Similar trends were observed in amino acid‐supplemented OJ, albeit at a slower rate. In contrast, variations in sugar or organic acid composition had negligible effects on the physiological status of the cells. In summary, natural variation in ascorbic acid or amino acid concentrations could potentially have an adverse effect on the microbiological safety of orange juice