الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 149 |  |  |
| | | from | 149 | | |
Abstract
Bacterial resistance to multiple antibiotics is a great health problem; hence different antibacterial agents need to be constantly discovered. In this work, the antimicrobial activities of the tested fluoroaryl-2, 2′-bichalcophene derivatives were evaluated against S. aureus, Bacillus sp. and Rhodotorula ATL72. The impact of these bichalcophenes was studied on the ultrastructure level via SEM, molecular level via SDS-PAGE and RPD-PCR methods and electrochemical level using biosensor.
Based on the results of preliminary experiment, the antibacterial activity against the tested microorganisms was enhanced due to the presence of fluorine atom, so fluoroarylbichalcophenes had higher activity than that of the parent bithiophene derivative MA-0944 and the bifuran derivative MA-0947. The fluoroarylbichalcophenes showed a good suppressing effect on both Gram-positive bacteria and yeast. The compound MA-1156 displayed the best minimum inhibitory concentration (MIC) results among the tested fluoroarylbichalcophenes (16- 32 µM). Over a period of 7 days S. aureus, Bacillus sp. and Rhodotorula ATL72 did not develop any resistance to the tested fluoroarylbichalcophenes at higher concentrations (3x MIC). The impact fluoroarylbichalcophenes was obviously strong on genetic structure and protein pattern of tested microorganisms based on RAPD-PCR manipulation and SDS-PAGE profile. The biomarker assay detecting the protein changes based on SDS-PAGE profile showed that, there were high degrees of polymorphism especially with the samples treated with higher concentrations. Also the genetic changes based on RAPD-PCR manipulation of fluoroarylbichalcophenes manifested a polymorphic pattern when treated and untreated microorganisms were compared.
SEM micrographs of S. aureus cells treated with one sub-MIC concentration of each fluoroarylbichalcophene compound showed cells smaller in size, fewer in numbers, arranged in linear form and some of them were damaged when compared to the untreated sample which showed the typical character of S. aureus coccoid cells in cluster arrangement. The results of WST-test showed that cells treated with compound MA-1156 at all concentrations were unviable whereas some cells treated with MA-1114 were viable at all concentrations except the highest one; 128 µM. Biofilm formed at the electrode surface was used for bioelectrochemical measurements of the S. aureus cell viability. Treated S. aureus were more sensitive to the fluoroarylbichalcophenes than the control untreated cells. In conclusion these fluoroarylbichalcophene compounds could be recommended as effective antibacterial agents.