2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures
2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures
2. ENVIRONMENTAL ChEMISTRy & TEChNOLOGy 2.1. Lectures
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Chem. Listy, 102, s265–s1311 (2008) Environmental Chemistry & Technology<br />
Table I<br />
Concentration of dichlone used in MIC testing<br />
Dilution 1 Dilutions 2 Dilutions 3<br />
0.001 μg ml –1 0.125 μg ml –1 16.0 μg ml –1<br />
0.002 μg ml –1 0.25 μg ml –1 3<strong>2.</strong>0 μg ml –1<br />
0.004 μg ml –1 0.5 μg ml –1 64.0 μg ml –1<br />
0.008 μg ml –1 1.0 μg ml –1 128.0 μg ml –1<br />
0.016 μg ml –1 <strong>2.</strong>0 μg ml –1 256.0 μg ml –1<br />
0.032 μg ml –1 4.0 μg ml –1<br />
0.064 μg ml –1 8.0 μg ml –1<br />
HPLC technique: for the identification of 2,3-dichloronaphtoquinone<br />
in the samples a 1 mg ml –1 solution was prepared<br />
in acetonitrile and 10 μl injected into the HPLC system.<br />
The sample was injected three times.<br />
Mobile phase was 60 % acetonitrile with 40 % water.<br />
Chromatograms were registered at 254 nm.<br />
Results<br />
Antimicrobial susceptibility testing results show that the<br />
dichlone have no antimicrobial activity on Gram-negative<br />
bacteria Enterobacter aerogenes; in the same time the growth<br />
of Gram-positive coccus Enterococcus faecalis (both strains)<br />
was completly inhibited, as in Table II.<br />
Table II<br />
Dichlone’s MIC on Enterococcus faecalis strains<br />
Strain MIC [μg ml –1 ]<br />
E. faecalis – ATCC 29212 0.5<br />
E. faecalis – ATCC 19433 0.5<br />
As we mentioned in introduction, dichlone’s grade of<br />
remanence, in the inoculated culture mediums for MIC was<br />
determined by HPLC. The chromatograms of the mentioned<br />
naphtoquinone obtained at the most effective chromatographic<br />
conditions are shown in Figs. <strong>2.</strong> and 3.<br />
The height and area of PDA signal (254 nm) for this<br />
naphtoquinone confirmed the calculated value for MIC.<br />
Fig. <strong>2.</strong> hPLC chromatogram for dichlone’s MIC (e. faecalis<br />
– ATCC 29212)<br />
s480<br />
Fig. 3. hPLC chromatogram for dichlone’s MIC (E. faecalis<br />
– ATCC 19433)<br />
Conclusions<br />
The results of this study show that dichlone has no antimicrobial<br />
activity on Gram-negative germs (Enterobacter<br />
aerogenes). In the mean time, dichlone’s MIC on Gram-positive<br />
germs (Enterococcus faecalis – both strains) it was at<br />
0.5 μg ml –1 in liquid culture media (M-H broth). This concentration<br />
was confirmed by HPLC determination.<br />
This work has been supported by Romanian Ministry<br />
of Education and Research, National Authority for Scientific<br />
Research, National Centre for Programmes Management<br />
on Project No. 1885 NANOQMED: “Obtaining and characterization<br />
of new targeted-nanodrugs with naphtoquinonic<br />
active substance”.<br />
REFEREnCES<br />
1. Clark J. A., Burger C. A., Sabatinos L. E.: Can. J. Microbiol.,<br />
28, 1002 (1982).<br />
<strong>2.</strong> Baudart J., Coallier J., Laurent P., Prévost M.: Appl.<br />
Environ. Microbiol., 68, 5057 (2002).<br />
3. Filipkowska Z.: Acta Microbiol. Pol., 52, 57 (2003).<br />
4. Delbés C., Ali-Mandjee L., Montel M. C.: Appl. Environ.<br />
Microbiol., 73, 1882 (2007).<br />
5. Johnston L. M., Jaykus L. A.: Appl. Environ. Microbiol.,<br />
70, 3133 (2004).<br />
6. Hayes J. R. English L. L. Carr L. E., Wagner D. D.,<br />
Joseph S. W.: Appl. Environ. Microbiol., 70, 6005<br />
(2004).<br />
7. Morosini M. I., Garciá-Castillo M., Coque T. M., Valverde<br />
A., novais A., Loza E., Baquero, Cantón R.: Antimicrob.<br />
Ag. Chemoth., 50, 2695 (2006).<br />
8. Sawant A. A., Hegde n. V., Straley B. A., Donaldson<br />
S. C., Love B. C., Knabel S. J., Jayarao B. M.: Appl.<br />
Environ. Microbiol., 73, 156 (2007).<br />
9. Macovei L., Zurek L.: Appl. Environ. Microbiol., 72,<br />
4028 (2006).<br />
10. Macovei L., Zurek L.: Appl. Environ. Microbiol., 73,<br />
6740 (2007).<br />
11. Masuda K., Funayama S., Komiyama K., Umezawa, I.,<br />
Ito K.: J. nat. Prod., 50, 418 (1987).