FTIR microscopy as a method for identification of bacterial and fungal infections.
ABSTRACT Fourier-transform infrared (FTIR) microscopy is considered to be a comprehensive and sensitive method for detection of molecular changes in cells. The advantage of FTIR microspectroscopy over conventional FTIR spectroscopy is that it facilitates inspection of restricted regions of the examined sample. In the present study, we examined the potential of FTIR microscopy as an easy, rapid and reliable technique for discrimination between bacteria and fungi both of which are involved in various human and other animal infections. In many cases, there is no easy and rapid technique for identifying the cause of such infections whether it is bacteria, fungi or both. Knowing such information in a rapid way could be highly important for effective therapy. Our results proved detectable and significant spectral differences between bacterial and fungal samples. Representative peaks of bacteria and fungi appeared clearly in the spectra of a mixture of bacteria and fungi. It seems that this technique could be used for rapid discrimination between bacterial and fungal infections and contaminations.
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ABSTRACT: Fourier transform infrared (FTIR) spectroscopy was carried out to ascertain the mechanism of Ca-alginate and mannitol protection of cell envelope components and secondary proteins of Bifidobacterium animalis subsp. lactis Bb12 after freeze-drying and after 10 weeks of storage at room temperature (25°C) at low water activities (a(w)) of 0.07, 0.1, and 0.2. Preparation of Ca-alginate and Ca-alginate-mannitol as microencapsulants was carried out by dropping an alginate or alginate-mannitol emulsion containing bacteria using a burette into CaCl(2) solution to obtain Ca-alginate beads and Ca-alginate-mannitol beads, respectively. The wet beads were then freeze-dried. The a(w) of freeze-dried beads was then adjusted to 0.07, 0.1, and 0.2 using saturated salt solutions; controls were prepared by keeping Ca-alginate and Ca-alginate-mannitol in aluminum foil without a(w) adjustment. Mannitol in the Ca-alginate system interacted with cell envelopes during freeze-drying and during storage at low a(w)s. In contrast, Ca-alginate protected cell envelopes after freeze-drying but not during 10-week storage. Unlike Ca-alginate, Ca-alginate-mannitol was effective in retarding the changes in secondary proteins during freeze-drying and during 10 weeks of storage at low a(w)s. It appears that Ca-alginate-mannitol is more effective than Ca-alginate in preserving cell envelopes and proteins after freeze-drying and after 10 weeks of storage at room temperature (25°C).Applied and environmental microbiology 07/2012; 78(19):6914-21. · 3.69 Impact Factor
Article: Fourier transform infrared as a powerful technique for the identification and characterization of filamentous fungi and yeasts.[show abstract] [hide abstract]
ABSTRACT: Fourier transform infrared is considered a powerful technique for characterizing chemical compositions of complex probes such as microorganisms. It has successfully been applied to fungal identification. In this paper, the current state of identification and characterization of filamentous fungi and yeasts by Fourier transform infrared is reviewed.Research in Microbiology 03/2010; 161(2):168-75. · 2.76 Impact Factor
Article: Morphological and geochemical evidence of eumelanin preservation in the feathers of the Early Cretaceous bird, Gansus yumenensis.[show abstract] [hide abstract]
ABSTRACT: Recent studies have shown evidence for the preservation of colour in fossilized soft tissues by imaging melanosomes, melanin pigment containing organelles. This study combines geochemical analyses with morphological observations to investigate the preservation of melanosomes and melanin within feathers of the Early Cretaceous bird, Gansus yumenensis. Scanning electron microscopy reveals structures concordant with those previously identified as eumelanosomes within visually dark areas of the feathers but not in lighter areas or sedimentary matrices. Fourier transform infrared analyses show different spectra for the feathers and their matrices; melanic functional groups appear in the feather including carboxylic acid and ketone groups that are not seen in the matrix. When mapped, the carboxylic acid group absorption faithfully replicates the visually dark areas of the feathers. Electron Paramagnetic Resonance spectroscopy of one specimen demonstrates the presence of organic signals but proved too insensitive to resolve melanin. Pyrolysis gas chromatography mass spectrometry shows a similar distribution of aliphatic material within both feathers that are different from those of their respective matrices. In combination, these techniques strongly suggest that not only do the feathers contain endogenous organic material, but that both geochemical and morphological evidence supports the preservation of original eumelanic pigment residue.PLoS ONE 01/2011; 6(10):e25494. · 4.09 Impact Factor