Antibacterial effect of edible coatings with essential oil

Food preservation technologies are a continuously renewed area because of industrial and customer needs, social transformation and environmentally friendly processing and climate change. The shelf life of perishable food products must be extended with different technologies, for example using green methods like the edible coating (EC). EC is made from different biopolymers (chitosan, alginate, gelatine, agar), the effect can increase with using plant extracts. In this study, the effect of chitosan EC, chitosan EC+thyme essential oil (EO); effect of alginate EC, alginate EC+thyme EO was examined on fresh chicken breast having artificial contamination with Escherichia coli; Enterococcus faecalis, that the EC can extend the shelf life. The organoleptic quality of baked treated chicken breast was established also. Based on the result both EC can decrease the cell number (with 1-3 log CFU/g) on treated chicken breast and this antimicrobial effect was enhanced with thyme essential oil (3.2 µl/ml concentration). There was significant differences (p<0.05) between the two edible coatings. Alginate had better preservation effect, than chitosan. However, the thyme EO could increase the antimicrobial activity of chitosan in higher values, than the effect of alginate EC. In this experiment, the E. faecalis was more sensitive to treatment than the E. coli. In conclusion, the edible coating can be used as an alternative preservation technique and these combined with essential oils can extend the shelf life of chicken breast fillet

Antibacterial effect of edible coatings with essential oil

Food preservation technologies are a continuously renewed area because of industrial and customer needs, social transformation and environmentally friendly processing and climate change. The shelf life of perishable food products must be extended with different technologies, for example using green methods like the edible coating (EC). EC is made from different biopolymers (chitosan, alginate, gelatine, agar), the effect can increase with using plant extracts. In this study, the effect of chitosan EC, chitosan EC+thyme essential oil (EO); effect of alginate EC, alginate EC+thyme EO was examined on fresh chicken breast having artificial contamination with Escherichia coli; Enterococcus faecalis, that the EC can extend the shelf life. The organoleptic quality of baked treated chicken breast was established also. Based on the result both EC can decrease the cell number (with 1-3 log CFU/g) on treated chicken breast and this antimicrobial effect was enhanced with thyme essential oil (3.2 µl/ml concentration). There was significant differences (p<0.05) between the two edible coatings. Alginate had better preservation effect, than chitosan. However, the thyme EO could increase the antimicrobial activity of chitosan in higher values, than the effect of alginate EC. In this experiment, the E. faecalis was more sensitive to treatment than the E. coli. In conclusion, the edible coating can be used as an alternative preservation technique and these combined with essential oils can extend the shelf life of chicken breast fillet

Genomiális eltérések és génexpresszió közötti kapcsolat vizsgálata, melanomák metasztázisképzésre jellemző genetikai markerek kutatása = Association between genomic alterations and gene expression, search for genetic markers in association with melanoma metastasis formation

A projekt keretében melanomák genom és génexpressziós eltéréseit analizáltuk. Q-PCR-el gyakori mutációt találtunk a BRAF és NRAS onkogénekre. BRAF mutációval asszociálódott jellegzetes eltérések a 7p22, 7q21, 7q31 szakaszok többlete és a 10q21, 10q26 lókuszok vesztése voltak. Hierachikus klaszter analizissel két jellegzetes molekuláris alosztályt figyeltünk meg, amely a kevésbé aggresszív tumoroktól az agresszív daganatokat egyértelműen elválasztották. 1095 eltérő expressziójú gén az ulcerációval asszociálódott. Közülük 1021 gén alulregulált volt a rosszprognózisú csoportban, és érdekes, hogy ugyanezek a gének magas expressiójuak voltak a másik csoportban. Metasztázisok génexpressziója az ulcerációval mutatott azonos mintázatot. Az ulcerált felszínű melanomákban csökkent expressziójú gének funkcióját vizsgálva kimutattuk, hogy többségük a bőr- és szőrfejlődési funkció, dermatológiai betegségek, daganatfejlődés, sejtosztódás a sejtciklus, sejt-sejt interakció és sejtmotilitás szabályozó folyamatokhoz tartozik, a p53, ERK/MAP, IP3/AKT és WNT/? katenin, Nf-?B molekulási útvonalakon hatva. Interfázisos FISH analízissel kimutattuk, hogy az EGFR génkópiaszám többlete, primer melanomákban rossz prognózissal társul. A 9p21-es lokusz delécióját mind a korai, mind a késői melanomákban megfigyeltük. Nem találtunk szoros korrelációt a 9p21-es lokusz genetikai eltérései és a daganatok klinikopatológiai tulajdonságai között. | Within the framework of this project using Q-PCR we found frequent mutation of the BRAF and NRAS oncogenes in primary melanomas. Genom alterations exclusively associated with BRAF mutation were gains of 7p22, 7q21, 7q31, and losses of 10q21, 10q26. Unsupervised cluster analysis of geneexpression data revealed two characteristic molecular subclasses of melanoma, segregating aggressive tumors from less aggressive ones. Differentially expressed genes (1095) were associated with ulceration. Majority these (1021) were downregulated in subclass with bad prognosis and upregulated in the less aggressive group. Geneexpression signature of metastastases displayed similar signature, majority of the genes defined for the ulcerated lesions showed reduced expression in metastatic tumors. Using functional annotations five networks were identified belonging into the hair and skin development-, cancer-, cellular growth- and proliferation and affect the p53, Wnt/?-catenin and Nf-?B signaling pathways. By FISH we demonstrated that elevated copies of EGFR gene is associated with poor prognosis. Outcome of patients whose primary tumors had highly amplified EGFR gene was poor. Correlation between the gene amplification, mRNA level and protein expression was not linear. 9p21 deletion was present in early and late stages of the disease with similar frequency. We could not find strong correlation the 9p21 status of melanomas and the patients? clinical parameters

Bacterial evolution of antibiotic hypersensitivity.

The evolution of resistance to a single antibiotic is frequently accompanied by increased resistance to multiple other antimicrobial agents. In sharp contrast, very little is known about the frequency and mechanisms underlying collateral sensitivity. In this case, genetic adaptation under antibiotic stress yields enhanced sensitivity to other antibiotics. Using large-scale laboratory evolutionary experiments with Escherichia coli, we demonstrate that collateral sensitivity occurs frequently during the evolution of antibiotic resistance. Specifically, populations adapted to aminoglycosides have an especially low fitness in the presence of several other antibiotics. Whole-genome sequencing of laboratory-evolved strains revealed multiple mechanisms underlying aminoglycoside resistance, including a reduction in the proton-motive force (PMF) across the inner membrane. We propose that as a side effect, these mutations diminish the activity of PMF-dependent major efflux pumps (including the AcrAB transporter), leading to hypersensitivity to several other antibiotics. More generally, our work offers an insight into the mechanisms that drive the evolution of negative trade-offs under antibiotic selection

Genome-wide analysis captures the determinants of the antibiotic cross-resistance interaction network

Understanding how evolution of antimicrobial resistance increases resistance to other drugs is a challenge of profound importance. By combining experimental evolution and genome sequencing of 63 laboratory-evolved lines, we charted a map of cross-resistance interactions between antibiotics in Escherichia coli, and explored the driving evolutionary principles. Here, we show that (1) convergent molecular evolution is prevalent across antibiotic treatments, (2) resistance conferring mutations simultaneously enhance sensitivity to many other drugs and (3) 27% of the accumulated mutations generate proteins with compromised activities, suggesting that antibiotic adaptation can partly be achieved without gain of novel function. By using knowledge on antibiotic properties, we examined the determinants of cross-resistance and identified chemogenomic profile similarity between antibiotics as the strongest predictor. In contrast, cross-resistance between two antibiotics is independent of whether they show synergistic effects in combination. These results have important implications on the development of novel antimicrobial strategies

Network-level architecture and the evolutionary potential of underground metabolism

A central unresolved issue in evolutionary biology is how metabolic innovations emerge. Low-level enzymatic side activities are frequent and can potentially be recruited for new biochemical functions. However, the role of such underground reactions in adaptation toward novel environments has remained largely unknown and out of reach of computational predictions, not least because these issues demand analyses at the level of the entire metabolic network. Here, we provide a comprehensive computational model of the underground metabolism in Escherichia coli. Most underground reactions are not isolated and 45% of them can be fully wired into the existing network and form novel pathways that produce key precursors for cell growth. This observation allowed us to conduct an integrated genome-wide in silico and experimental survey to characterize the evolutionary potential of E. coli to adapt to hundreds of nutrient conditions. We revealed that underground reactions allow growth in new environments when their activity is increased. We estimate that at least similar to 20% of the underground reactions that can be connected to the existing network confer a fitness advantage under specific environments. Moreover, our results demonstrate that the genetic basis of evolutionary adaptations via underground metabolism is computationally predictable. The approach used here has potential for various application areas from bioengineering to medical genetics