Current Issue : October - December Volume : 2018 Issue Number : 4 Articles : 5 Articles
Background. In this study, 18 methanol extracts from Cameroonian edible plants were tested for their antibacterial\nactivities against 26 strains of S. aureus; the role of efflux pumps in the resistance of tested bacteria and the antibiotic\nresistance-modulating activities against selected multidrug-resistant (MDR) phenotypes were also investigated. Methods.\nBroth microdilution assay was used to evaluate the antibacterial activity, the role of efflux pumps, and the antibiotic\nresistance-modulating effects of plant extracts. Results. Extracts from Dacryodes edulis seeds (DES) and Dacryodes edulis\nbark (DEB) were active against all 26 tested bacterial strains, within the minimal inhibitory concentration (MIC) range of\n256ââ?¬â??1024 Ã?¼g/mL. MIC values varied from 64 to 1024 Ã?¼g/mL against 96.2% of the 26 tested bacteria for Phaseolus vulgaris\nleaves (PVL), 92.3% for Azadirachta indica bark (AIB), Dacryodes edulis leaves (DEL), and Ricinodendron heudelotii\nleaves (RHL). The lowest MIC value of 64 Ã?¼g/mL was obtained with the extract from Cucurbita maxima beans (CMB)\nagainst MRSA4 strain and from Uapaca guineensis bark (UGB) against MRSA9 strain. Bacterial efflux pump inhibitor\n(EPI), carbonyl cyanide m-chlorophenyl hydrazone (CCCP), improved the activity of DES and UGB as well as that of\nextracts from Hibiscus esculentus leaves (HEL) and Uapaca guineensis leaves (UGL) against resistant S. aureus strains.\nAntibiotic-modulating effects against more than 70% of the S. aureus strains tested were obtained when RHL (at MIC/2)\nwas combined with CIP, ERY, and KAN (88.89%), CHL (88.89%), TET (77.78%), and STR (88.89%). Conclusion. The\npresent study demonstrated that the 13 tested plants had antistaphylococcal effects and that DES, HEL, UGL, and UGB\ncould be used in combination with EPI to combat resistance to Staphylococcus aureus. Also, it demonstrated that some\nstudied extracts and mostly RHL could be used as antibiotic resistance modulators to fight against resistant strains of\nS. aureus....
The present investigation was designed to check antimicrobial activity of combination of three extracts of Curcuma longa (CL), Ocimum santum (OS) and Gingiber officinale (GO) together and the development of suitable dosage form. Crude samples of CL, OS and GO were collected, air dried, powdered and extracted with 50% ethanol by maceration method and subjected for phytochemical analysis. Antimicrobial activity of individual extracts of CL, OS and GO CL, OS, GO and combined extract was carried out by the agar well diffusion method and tube dilution method. The extracts were tested on clinical isolates include aerobic, facultative bacteria namely Stapyhlococcus aureus ATCC 25921, Escherichia coli ATCC 25922, Bacillus subtilis and fungus Aspergillus niger. The combined extract showed greater antimicrobial activity than individual hydroalcoholic extracts. The minimum inhibitory concentration (MIC) of extracts varied from species of microorganisms, it was found to be 1 to 1.2 mg/ml. Further combined extract was used for preparation of topical formulations such as gel (1%) and ointment (1%). The further antimicrobial study of gel and ointment was compared which showed no loss of antimicrobial activity of extracts after six months. Then both the formulations were evaluated for physical characteristics and stability study....
The present investigation deals with the fabrication of quercetin loaded chitosan nanoparticles for their superior in-vitro antibacterial activity against dental pathogens. Developed nanoparticles were characterized for particle size and zeta potential. Results revealed that chitosan enhances antimicrobial activity towards dental pathogens viz. Bacillus pumilus, Bacillus thuringiensis and Pseudomonas aeruoginosa, Acinetobacter junii, Enterococcus faecalis when fabricated as quercetin-loaded chitosan nanoparticles compared to bare quercetin....
Xenorhabdus stockiae PB09 bacterium has been shown to exhibit antifungal activity against several plant pathogens. To improve\nits efficacy, the optimization of the nutritional components in culture media was performed. The medium components that have\nsignificant effects on antifungal activity of X. stockiae PB09 were initially identified using a fractional factorial design. Response\nsurface methodology and central composite design were then used to create a model for optimizing the levels of carbon, nitrogen,\nand mineral sources that maximize antifungal activity of X. stockiae PB09. After that, the suitable carbon, nitrogen, and mineral\nsources were selected and adjusted by the second-order polynomial regression model, which predicted that 98.62% of antifungal\nactivity could be obtained when the medium contained sucrose, yeast extract, NaCl, and K2HPO4 at 3.24, 23.71, 5.46, and 2.73 g/L,\nrespectively. Laboratory verification of this recipe resulted in the antifungal activity at 97.95% in the shake flask experiment after\n48-hour cultivation, which was significantly 27.22% higher than that obtained by using the TSB medium. In addition, X. stockiae\nPB09 cultured in the verified recipe by using 5 L fermenter could effectively inhibit the mycelial growth of Phytophthora sp.,\nRhizoctonia solani, Pythium sp., and Fusarium oxysporum. This study demonstrated that the RSM and CCD were shown to be\nvaluable tools for optimizing the culture medium that maximize the antifungal activity of X. stockiae PB09....
Marine invertebrates, such as sponges, tunicates and cnidarians (zoantharians and\nscleractinian corals), form functional assemblages, known as holobionts, with numerous microbes.\nThis type of species-specific symbiotic association can be a repository of myriad valuable low\nmolecular weight organic compounds, bioactive peptides and enzymes. The zoantharian Protopalythoa\nvariabilis (Cnidaria: Anthozoa) is one such example of a marine holobiont that inhabits the coastal\nreefs of the tropical Atlantic coast and is an interesting source of secondary metabolites and\nbiologically active polypeptides. In the present study, we analyzed the entire holo-transcriptome\nof P. variabilis, looking for enzyme precursors expressed in the zoantharian-microbiota assemblage\nthat are potentially useful as industrial biocatalysts and biopharmaceuticals. In addition to hundreds\nof predicted enzymes that fit into the classes of hydrolases, oxidoreductases and transferases\nthat were found, novel enzyme precursors with multiple activities in single structures and\nenzymes with incomplete Enzyme Commission numbers were revealed. Our results indicated\nthe predictive expression of thirteen multifunctional enzymes and 694 enzyme sequences with\npartially characterized activities, distributed in 23 sub-subclasses. These predicted enzyme structures\nand activities can prospectively be harnessed for applications in diverse areas of industrial and\npharmaceutical biotechnology....
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