The metabolic potency of fungi as camptothecin producer elevates their prospective use as an industrial platform for commercial production, however, the loss of camptothecin productivity by fungi with the storage and subculturing are the major obstacle. Thus, screening for endophytic fungal isolates inhabiting ethnopharmacological plants with an obvious metabolic stability and sustainability for camptothecin biosynthesis could be one of the most feasible paradigms. Aspergillus terreus ON908494.1, an endophyte of Cestrum parqui was morphologically and molecularly verified, displaying the most potent camptothecin biosynthetic potency. The chemical identity of A. terreus camptothecin was confirmed from the HPLC, FTIR and LC–MS/MS analyses, gave the same molecular structure and mass fragmentation patterns of authentic one. The purified putative camptothecin displayed a strong anticancer activity towards HepG-2 and MCF-7 with IC50 values 0.96 and 1.4 µM, respectively, with no toxicity to OEC normal cells. As well as, the purified camptothecin displayed a significant antifungal activity towards fungal human pathogen Candida albicans, Aspergillus flavus, and A. parasiticus, ensuring the unique structural activity relationships of A. terreus camptothecin, as a powerful dually active anticancer and antimicrobial agent. The camptothecin productivity of A. terreus was maximized by bioprocessing with Plackett–Burman design, with an overall 1.5 folds increment (170.5 µg/L), comparing to control culture. So, the optimal medium components for maximum yield of camptothecin by A. terreus was acid why (2.0 mL/L), Diaion HP20 (2.0 g/L), Amberlite XAD (2.0 g/L), dextrin (5.0 g/L), glucose (10.0 g/L), salicylic acid (2.0 g/L), serine (4.0 g/L), cysteine (4.0 g/L) and glutamate (10.0 g/L), at pH 6 for 15 days incubation. By the 5th generation of A. terreus, the camptothecin yield was reduced by 60%, comparing to zero culture. Interestingly, the productivity of camptothecin by A. terreus has been completely restored and over increased (210 µg/L), comparing to the 3rd generation A. terreus (90 µg/L) upon addition of methanolic extracts of Citrus limonum peels, revealing the presence of some chemical signals that triggers the camptothecin biosynthetic machinery. The feasibility of complete restoring of camptothecin biosynthetic-machinery of A. terreus for stable and sustainable production of camptothecin, pave the way for using this fungal isolate as new platform for scaling-up the camptothecin production.
Methicillin-resistant and vancomycin-resistant Staphylococcus aureus (MRSA and VRSA) are zoonotic life-threatening pathogens, and their presence in food raises a public health concern. Yet, scarce data are available regarding MRSA and VRSA in both ready-to-eat (RTE) meat and food handlers. This study was undertaken to determine the frequency, antimicrobial resistance, and biofilm-forming ability of MRSA and VRSA isolated from RTE meat (shawarma and burger) and humans (food handlers, and hospitalized patients) in Zagazig city, Sharkia Governorate, Egypt. We analyzed 176 samples (112 human samples: 72 from hospitalized patients and 40 from food handlers, 64 RTE meat samples: 38 from shawarma and 26 from burger). Using phenotypic, PCR-based identification of nuc gene and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), 60 coagulase-positive S. aureus (COPS) isolates were identified in the samples as follow: RTE meat (15/64, 23.4%), hospitalized patients (33/72, 45.8%) and food handlers (12/40, 30%). All the COPS isolates were mecA positive (and thus were classified as MRSA) and multidrug resistant with multiple antibiotic resistance indices ranging from 0.25 to 0.92. Overall, resistance to cefepime (96.7%), penicillin (88.3%), were common, followed by ampicillin-sulbactam (65%), ciprofloxacin (55%), nitrofurontoin (51.7%), and gentamicin (43.3%). VRSA was detected in 30.3% of COPS hospitalized patient’s isolates, 26.7% of COPS RTE meat isolates and 25% of COPS food handler’s isolates. VanA, vanB, or both genes were detected in 64.7, 5.9, and 29.4% of all VAN-resistant isolates, respectively. The majority of the COPS isolates (50/60, 83.3%) have biofilm formation ability and harbored icaA (76%), icaD (74%), icaC (50%), and icaB (46%) biofilm-forming genes. The bap gene was not detected in any of the isolates. The ability of MRSA and VRSA isolates to produce biofilms in addition to being resistant to antimicrobials highlight the danger posed by these potentially virulent microorganisms persisting in RTE meat, food handlers, and patients. Taken together, good hygiene practices and antimicrobial surveillance plans should be strictly implemented along the food chain to reduce the risk of colonization and dissemination of MRSA and VRSA biofilm-producing strains.
The effects of packaging atmosphere, storage temperature and oregano essential oil (EO) on growth of Listeria monocytogenes on ready-to-eat smoked turkey were studied. Smoked turkey slices were inoculated with a strain of Listeria monocytogenes Scott A (5.95, 5.28 and 5.26 log CFU/g) then vacuum packaged (VP), modified atmosphere packaging (MAP: 40% CO 2 and 60% N 2 ) and MAP with oregano essential oil (MAPEO), respectively. The treated slices were then stored at 0, 5, 10 and 15 °C for 179.88 days and the L. monocytogenes Scott A’s growth and microbial shelf life were monitored. The combination of MAP or MAPEO and storage temperature did not allow growth of L. monocytogenes higher than log 1 CFU/g during all storage periods. While in VP temperature combinations, the multiplication of bacteria were ≥ 1 log CFU/g. In VP, MAP and MAPEO smoked turkey, the growth of L. monocytogenes increased regardless of storage temperature. In MAPEO samples the inoculum in the product was suppressed by ca. 5 log CFU/g at 0, 10 and 15 °C at 180, 117 and 81 days of storage, respectively. The inhibition of L. monocytogenes in ready-to-eat smoked turkey by the combinations of MAP and MAPEO was enhanced by storage at 0 or 5 °C. The MAPEO system can be used effectively to control growth of pathogen in processed food when maintaining fixed temperature measures is difficult.
Laccase enzyme has many important applications as bioremediation and removal of environmental wastes and also in industrial processes. Therefore, large-scale of novel producers of laccase is demanded to use cheap and low cost substrates. Hence, solid state fermentation is the best strategy to achieve this proposes. The present study is designed to optimize laccase production by Streptomyces mutabilis A17 using agro-wastes including rice bran, castor seed cake, wheat bran, wheat straw, soybeans cake, peanut cake, cotton seed cake and chicken feathers. Cotton seed cake significantly enhanced S. mutabilis A17 laccase production when it was incubated for 6 days at 37°C and 70% moisture content in presence of yeast extract and glucose as the best nitrogen and carbon sources, respectively. After purification steps, the purified laccase showed maximum activity at 40°C and pH 8.0 within stability pH range of 7.0 to 9.0. Laccase activity was highly increased to 195, 180 and 166% by the addition of Ba +2 , Cu +2 and Mn +2 , respectively. Sulfa drugs and synthetic dyes cause various pollutants due to their toxic effects in different environments. Therefore, a purified laccase was utilized for removal of sulfa drugs as sulfadiazine (SDZ) and sulfathiazole (STZ) and also synthetic dyes. The results showed that the maximal enzymatic removal of SDZ and STZ was attained at 50°C and pH 6.0 for 1 h at presence of 1mM HBT(1-hydroxybenzotriazole) as a laccase mediator by removal percentage of 73% and 90%, respectively. Detoxification effects of laccase-treated sulfa drugs and two synthetic dyes; congo red and malachite green solutions, were investigated using microbial toxicity test. Our results indicated that the toxicity of these laccase-treated samples against tested bacterial strains were significantly decreased. It was concluded from this study that SSF laccase is playing an important role for decreasing the toxic effects of pharmaceutical wastes and organic pollutants.
Due to the challenge faced scientists to produce the natural product as an anticancer agent from cheap sources and in endeavor to ameliorate the rate of anticancer agents, the employment of fungal metabolite in creating a cordial proper process was prerequisite. In the present study, fungal metabolites are detected by thin layer chromatography. The fungal producer strain was isolated from the rhizosphere region of old cultivated soil. One fungal isolate out of bioassay ten isolates was showed to have the most potent anticancer and antioxidant activity; this fungal isolate was identified as belonging to Aspergillus fumigatus (A. fumigatus). Fungal extract of A. fumigatus showed an antioxidant activity using Diphenyl-1-picrylhydrazyl (DPPH) scavenging % at 94.5±0.70 with IC 50 at 5µg/ mL. To elucidate chemical analysis of the different bioactive compounds; A. Fumigatus metabolites extract was subjected to instrumental analysis such as GC. Mass. The A. fumigatus metabolite showed a promising anticancer activity. Inhibitory activity against Hepatocellular carcinoma cells was detected under these experimental conditions with IC 50 = 113 ± 3.7 µg/ml. This property can be further used to formulate new age drugs.
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