Special issues related to hematopoietic SCT in the Eastern Mediterranean region and the first regional activity report.

Although several centers are now performing allogeneic hematopoietic SCT (HSCT) in the Eastern Mediterranean (EM) region, the availability is still limited. Special issues including compatible donor availability and potential for alternative donor programs are discussed. In comparison to Europe and North America, differences in patterns of diseases and pre-HSCT general status, particularly for patients with BM failure, are described. Other differences including high sero-positivity for CMV, hepatitis B and C infection, and specific observations about GVHD and its relation to genetically homogeneous communities are also discussed. We report that a total of 17 HSCT programs (performing five or more HSCTs annually) exist in 9 countries of the EM region. Only six programs are currently reporting to European Group for Blood and Marrow Transplantation or Center for International Blood and Marrow Transplantation Research. A total of 7617 HSCTs have been performed by these programs including 5701 allogeneic HSCTs. The area has low-HSCT team density (1.56 teams per 10 million inhabitants vs 14.43 in Europe) and very low-HSCT team distribution (0.27 teams per 10 000 sq km area vs <1-6 teams in Europe). Gross national income per capita had no clear association with low-HSCT activity. Much improvement in infrastructure and formation of an EM regional HSCT registry are needed.

Effects of Cymbopogon citratus L. essential oil on the growth, morphogenesis and aflatoxin production of Aspergillus flavus ML2-strain.

The mycelial growth of Aspergillus flavus Link was completely inhibited using 1.5 (microl/ml or 2.0 (microl/ml of Cymbopogon citratus essential oil applied by fumigation or contact method in Czapek's liquid medium, respectively. This oil was found also to be fungicidal at the same concentrations. The sublethal doses 1.0 and 1.5 (microl/ml inhibited about 65% of fungal growth after five days of incubation and delayed conidiation as compared with the control. Microscopic observations using Light Microscope (LM), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were carried out to determine the ultra structural modifications of A. flavus hyphae after treatment with C. citratus essential oil. The hyphal diameter decreased and hyphal wall appeared as precipitates and disappeared in some regions. This oil also caused plasma membrane disruption and mitochondrial structure disorganization. Moreover, Ca(+2), K(+) and Mg(+2) leakages increased from the fumigated mycelium and its total lipid content decreased, while the saturated and unsaturated fatty acids increased. One of the most important results obtained during this study was the ability of C. citratus essential oil at its sublethal dose to completely inhibit aflatoxin B(1) production from A. flavus. These findings increase the possibility of exploiting C. citratus essential oil as an effective inhibitor of biodegradation and storage contaminating fungi and also in fruit juice preservation.

Effects of Cymbopogon citratus L. essential oil on the growth, lipid content and morphogenesis of Aspergillus niger ML2-strain.

The mycelial growth of Aspergillus niger van Tieghem was completely inhibited using 1.5 (microl/ml or 2.0 (microl/ml of Cymbopogon citratus essential oil applied by fumigation or contact method in Czapek liquid medium, respectively. This oil was found also to be fungicidal at the same concentrations. The sublethal doses 1.0 and 1.5 (microl/ml inhibited about 70% of fungal growth after five days of incubation and delayed conidiation as compared with the control. Microscopic observations using Light Microscope (LM), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were carried out to determine the ultra structural modifications of A. niger hyphae after treatment with C. citratus essential oil. The hyphal diameter and hyphal wall appeared markedly thinner. This oil also caused plasma membrane disruption and mitochondrial structure disorganization. Moreover, Ca+2, K+ and Mg+2 leakages increased from the fumigated mycelium and its total lipid content decreased, while the saturated fatty acids decreased and unsaturated fatty acids increased. These findings increase the possibility of exploiting C. citratus essential oil as an effective inhibitor of biodegrading and storage contaminating fungi and in fruit juice preservation.

Effect of Cymbopogon citratus L. essential oil on growth and morphogenesis of Saccharomyces cerevisiae ML2-strain.

The growth of Saccharomyces cerevisiae was completely inhibited using 2.0 microl/ml or 4.0 microl/ml of Cymbopogon citratus essential oil applied by fumigation or contact method in Sabouraud's broth medium, respectively. This oil was found also to be fungicidal at the same concentrations. The sublethal doses 1.0 and 3.0 microl/ml inhibited about 98% of yeast growth after 24 hr of incubation as compared with the control. Microscopic observations using Light Microscope (LM), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) showed morphogenic and ultrastructure changes in the fumigated cells with 1.0 microl/ml of the oil. These changes including decrease in cell size, depressions on the surface of the cells, alteration in cell wall thickness and disruption of plasma membrane. Moreover, Ca(+2), K(+) and Mg(+2) leakages increased from the fumigated cells and its total lipid content decreased. Also, the fatty acid composition was altered with decrease in the amount of saturated fatty acids and increase in the amount of unsaturated fatty acids.

Antimicrobial activity of some essential oils against microorganisms deteriorating fruit juices.

Seventeen microbial species including 10 fungal taxa, two yeasts and five bacteria, were isolated from freshly prepared orange, guava and banana juices kept in open bottles at room temperature for 7 days. Eight different essential oils, from local herbs, were tested for their antimicrobial activity against these test organisms. The essential oils of Cymbopogon citratus, Ocimum basilicum and Origanum majorana were found to be highly effective against these microorganisms. Aspergillus niger, A. flavus and Saccharomyces cerevisiae, the most prevalent microorganisms in juice, showed the highest resistance against these essential oils. GC-MS analysis showed that while e-citral, a'-myrcene, and z-citral represent the major components (75.1%) of the essential oil of Cymbopogon citratus; bezynen,1-methyl-4-(2-propenyl), 1,8-cineole and trans-a'-bisabolene were the main components (90.6%) of Ocimum basilicum; whereas 3-cyclohexen-1-01,4-methyl-1(1-methylethyl)-(CAS), c-terpinene and trans-caryophyllene represent the major components (65.1%) of Origanum majorana. These three essential oils were introduced into juices by two techniques namely, fumigation and direct contact. The former technique showed more fungicidal effect than the latter one against A. flavus, A. niger, and S. cerevisiae. The essential oil of Cymbopogon citratus by comparison to other test oils showed the strongest effect against these fungi with a minimum inhibitory concentration of 1.5 µl/ml medium and a sublethal concentration of 1.0 µl/ml. The antimicrobial activity of this oil is thermostable at 121℃ for 30 min.

Use of propolis and ultragriseofulvin to inhibit aflatoxigenic fungi.

Propolis ethanolic extract (PEE) at 3 and 4 g/L and ultragriseofulvin (UG) at 0.75 and 1 g/L reduced the percentage of conidia germination in two Aspergillus flavus isolates. PEE at 1-4 g/L decreased the mycelial dry mass of A. flavus isolates by 11-80%, and aflatoxin B1 production by 34-100%. UG concentrations of 0.25-1 g/L reduced the growth and aflatoxin B1 production of the isolates by 16-88 and 48-98%, respectively. Any increase in PEE and UG concentration was accompanied by a clear decrease in the per cent conidia germination, growth and aflatoxin B1 production. At equal concentration, UG was about 4-times more effective than PEE.

Experimental evidence for the occurrence in honey of specific substances active against microorganisms.

Numbers of micro-organisms in sewage, soil, air and tap-water counted on media containing honey were lower than those counted on the same media containing equivalent concentrations of the sugars known to occur in honey. Similar experiments achieved with specific micro-organisms showed that honey had more pronounced inhibitory effects than the equivalent sugar solutions on Salmonella sp., Escherichia coli, Aspergillus niger and Penicillium chrysogenum, but not on Bacillus subtilis and Saccharomyces cerevisiae. These results are understood in view of the occurrence in honey of specific compounds active mainly against Gram negative bacteria and higher fungi.