Browsing by Subject "ANTIMICROBIALS"

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  • Sivaranjani, Murugesan; Leskinen, Katarzyna; Aravindraja, Chairmandurai; Saavalainen, Päivi; Pandian, Shunmugiah Karutha; Skurnik, Mikael; Ravi, Arumugam Veera (2019)
    Background: Alpha-mangostin (alpha-MG) is a natural xanthone reported to exhibit rapid bactericidal activity against Gram-positive bacteria, and may therefore have potential clinical application in healthcare sectors. This study sought to identify the impact of alpha-MG on Staphylococcus epidermidis RP62A through integrated advanced omic technologies. Methods: S. epidermidis was challenged with sub-MIC (0.875 mu g/ml) of alpha-MG at various time points and the differential expression pattern of genes/proteins were analyzed in the absence and presence of alpha-MG using RNA sequencing and LC-MS/MS experiments. Bioinformatic tools were used to categorize the biological processes, molecular functions and KEGG pathways of differentially expressed genes/proteins. qRT-PCR was employed to validate the results obtained from these analyses. Results: Transcriptomic and proteomic profiling of alpha-MG treated cells indicated that genes/proteins affected by alpha-MG treatment were associated with diverse cellular functions. The greatest reduction in expression was observed in transcription of genes conferring cytoplasmic membrane integrity (yidC2, secA and mscL), cell division (ftsY and divlB), teichoic acid biosynthesis (tagG and dltA), fatty-acid biosynthesis (accB, accC, fabD, fabH, fabl, and fabZ), biofilm formation (icaA) and DNA replication and repair machinery (polA, polC, dnaE, and uvrA). Those with increased expression were involved in oxidative (katA and sodA) and cellular stress response (clpB, clpC, groEL, and asp23). The qRT-PCR analysis substantiated the results obtained from transcriptomic and proteomic profiling studies. Conclusion: Combining transcriptomic and proteomic methods provided comprehensive information about the antibacterial mode of action of alpha-MG. The obtained results suggest that alpha-MG targets S. epidermidis through multifarious mechanisms, and especially prompts that loss of cytoplasmic membrane integrity leads to rapid onset of bactericidal activity.
  • Lyhs, Ulrike; Frandsen, Henrik; Andersen, Birgitte; Nonnemann, Bettina; Hjulsager, Charlotte; Pedersen, Karl; Chriel, Mariann (2019)
    Background The quality of mink feed and raw ingredients affect health and growth. The objectives of this study were to examine the microbiological quality of ready-to-eat mink feed and its raw ingredients, screen the plant part of the feed for mycotoxins, and determine the hygiene of the production environment in the feed processing facilities. The results of the study are important for identification of critical steps in the feed production and for formulation of recommendations for improvements of production processes to obtain better quality feed. Feed and swab samples were taken at three Danish mink feed producers October 2016 and May 2017, respectively. Viable counts, detection of methicillin-resistant Staphylococcus aureus (MRSA), influenza virus and filamentous fungi were performed together with qualitative chemical analyses for bioactive fungal metabolites and mycotoxins. Swab samples were analyzed for total viable counts. Results Viable counts varied between 7.2 x 10(2) and 9.3 x 10(7) cfu/g in raw ingredients and between 10(7) and 10(9) cfu/cm(2) on different surfaces at the feed production facilities. A pork meat product, pork haemoglobin, pork liver and a poultry mix was found positive for MRSA, while monophasic Salmonella [4,5,12:i:-] was detected in a pork meat product. Neither MRSA nor Salmonella was detected in any ready-to-eat feed. Influenza A virus was not detected in any sample. Filamentous fungi were detected in all analysed samples of ready-to-eat feed while dihydro-demethyl-sterigmatocystin was found in almost 50% of all ready-to-eat feed samples and in 80% of the sugar beet pulp. Fumonisins and other Fusarium toxins were found especially in corn gluten meal and extruded barley and wheat. Conclusions Mink feed contained a cocktail of mycotoxins and bacteria, which may not per se cause clinical disease, but may affect organ function and animal performance and well-being.