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WOS: 000521110200115 …

Ilkit, Macit/0000-0002-1174-4182; Ergin, Cagri/0000-0001-7783-8723 WOS: 000341223900009 PubMed: 25052111 Trichophyton mentagrophytes and Trichophyton rubrum, are two of the frequently identified dermatophyte species in routine microbiology laboratories. Although newer technologies may assist in species-level identification, direct application of these methods usually require improvement in order to obtain reliable identification of these species. Earlier data have shown that dermatophytes may be identified with FT-IR spectroscopy although there are some limitations. In particular, the organic bond ranges in FT-IR spectra showed more irregularity because of the eucaryotic complexity of the molds. In this study, Tween-80 which is an inorganic molecule, was added to the dermatophyte growth medium in order to investigate its effect on FT-IR spectroscopy analysis of dermatophytes. Nine reference dermatophyte strains [5 T.mentagrophytes complex (T.asteroides CBS 424.63, T.erinacei CBS 344.79, CBS 511.73, CBS 677.86, T.mentagrophytes CBS 110.65) and 4 T.rubrum complex strains with different morphotypes (T.fluviomuniense CBS 592.68, T.kuryangei CBS 422.67, T.raubitschekii CBS 102856, T.rubrum CBS 392.58)] were included in the study. All strains were cultured on Sabouraud glucose agar either with or without 1% Tween-80 for three weeks. After the incubation period, superficial scrapings from each dermatophyte colony were analyzed using FT-IR spectroscopy. All measurements were performed in transmission mode between 4400 and 400 cm(-1). Numerous spectral window data were analyzed by principal component analysis and hierarchical clustering was performed. The second derivations of spectral ranges revealed clear grouping of T.mentagrophytes complex and T.rubrum complex in association over five separate spectral ranges. The findings also showed that while all of the T.mentagrophytes strains contained lipid compounds in their mold structure after Tween-80 incubation (p< 0.025), T.rubrum strains did not. Based on these results, it was concluded that culture medium containing Tween-80 was sufficient to enable differentiation of T.mentagrophytes complex from T.rubrum complex by FT-IR spectroscopy. This effect might be attributed to the possible transfer of lipid compounds from culture to cell structure during growth. Further studies with the use of large number of reference strains and clinical isolates exposed to different environmental factors, such as antifungal agents and inorganic ions, are needed to support these data indicating favorable effect of Tween-80 on the differentiation of T.mentagrophytes and T.rubrum complexes by FT-IR spectroscopy.

Conjugated linoleic acids (CLA) are a mixture of positional and geometric isomers of linoleic acid (cis-9, cis-12 octadecadienoic acid) with conjugated double bounds. Their principal dietary sources include ruminant and dairy fats, and CLA are shown to possess health beneficial effects on human health. Dairy cultures may biologically convert linoleic acid to CLA, but their capability is affected by several factors such as the source and amount of linoleic acid in medium and fermentation conditions. The objective of this study is to determine the ability of lactic cultures isolated from different cheeses to produce CLA from sunflower oil as a natural source of linoleic acid. Results indicated that three strains of Lactobacillus and two strains of Enterococcus were able to increase CLA concentration more than 30% based on the weight of sunflower oil added to model medium. It is recommended that the bioconversion capability of linoleic acid into CLA by these strains should be determined in actual dairy products.

Malassezia species which are lipophilic exobasidiomycetes fungi, have been accepted as members of normal cutaneous flora as well as causative agent of certain skin diseases. In routine microbiology laboratory, species identification based on phenotypic characters may not yield identical results with taxonomic studies. Lipophilic and lipid-dependent Malassezia yeasts require lipid-enriched complex media. For this reason, Fourier transform infrared (FT-IR) spectroscopy analysis focused on lipid window may be useful for identification of Malassezia species. In this study, 10 different standard Malassezia species (M.dermatis CBS 9145, M.furfur CBS 7019, M.japonica CBS 9432, M.globosa CBS 7966, M.nana CBS 9561, M.obtusa CBS 7876, M.pachydermatis CBS 1879, M.slooffiae CBS 7956, M.sympodialis CBS 7222 and M.yamatoensis CBS 9725) which are human pathogens, have been analyzed by FT-IR spectroscopy following standard cultivation onto modified Dixon agar medium. Results showed that two main groups (M1; M.globosa, M.obtusa, M.sympodialis, M.dermatis, M.pachydermatis vs, M2; M.furfur, M.japonica, M.nana, M.slooffiae, M.yamatoensis) were discriminated by whole spectra analysis. M.obtusa in M1 by 1686-1606 cm-1 wavenumber ranges and M.japonicum in M2 by 2993-2812 cm-1 wavenumber ranges were identified with low level discrimination power. Discriminatory areas for species differentiation of M1 members as M.sympodialis, M.globosa and M.pachydermatis and M2 members as M.furfur and M.yamatoensis could not be identified. Several spectral windows analysis results revealed that FT-IR spectroscopy was not sufficient for species identification of culture grown Malassezia species.