Fourier transform IR spectroscopic appraisal of radiation damage in Micrococcus luteus

Abstract

Fourier transform IR spectroscopy (FTIR) is used to analyze cells of Micrococcus luteus, the type species of the highly heterogeneous genus Micrococcus that belongs to the Micrococcaceae family. The cells of M. luteus, which is a Gram-positive and yellow-pigmented bacterium, are submitted to increasing doses of gamma radiation. Irradiation leads to the generation of reactive oxygen species that induce biochemical changes as shown in spectral profiles. Beyond a dose of 0.70 kGy, significant differences between samples are observed, particularly in the 1485-900 cm(-1) region, which contains information about membrane lipids, cell wall polysaccharides, and nucleic acids. After a dose of 16.50 kGy, M. luteus is reincubated for times ranging from 1 to 24 h. Postirradiation reincubated bacteria are found far from the control and irradiated cells (mainly in the 985-900 cm(-1) range), suggesting that a biomolecular rearrangement occurs as soon as reincubation begins in the growth medium. Thus, FTIR spectroscopy appears to be a very useful technique for the rapid visualization of the alterations induced by both the radiation and mutagenic response during reincubation. The use of mathematical methods gives good insight into the biomolecular compounds involved in these two mechanisms. In view of these preliminary results, we hypothesize that it can be successfully applied to any type of tissue and that it may be a future interesting tool for evaluating the effects of radiation in humans.

Phenotypic and molecular diversity of Meyerozyma guilliermondii strains isolated from food and other environmental niches, hints for an incipient speciation

“…None of the tools employed in this work has been able to discriminate between medical and environmental isolates within the NF group, although medical strains tended to cluster together in the FTIR dendrogram. This evidence confirms the high sensitivity of the metabolomic fingerprint in discriminating strains subject to different stressing conditions (Corte et al, 2012;Perromat et al, 2003).…”

Differentiation of Mesophilic and Thermophilic Bacteria with Fourier Transform Infrared Spectroscopy

“…The peak area ratio of bands at 1087 cm À1 and 1540 cm À1 (A 1087 /A 1540 ) is often used to illustrate the change of the DNA/ protein content of the cells. [36][37][38][39] A higher value of this ratio implies a higher DNA content. [36][37][38][39] The results shown in Table III suggest that the cellular DNA content was lower for thermophilic bacteria (0.30 6 0.10) compared to mesophilic bacteria (1.16 6 0.50) (p , 0.001).…”

“…49,52,53 Our results confirmed these studies since we found a significant decrease in the frequency of the carbonyl group, indicating an increase in the number of hydrogen bonds. The lower DNA/ protein ratio might suggest that the cellular DNA content was lower for thermophilic bacteria [36][37][38][39] (Table III).…”

Spectroscopic and chemometric approaches to radiobiological analyses

“…These investigations have since evolved to Raman spectroscopic studies of the effects of in-vitro proton irradiation of excised tissues [52], and radiotherapeutically irradiated (γ-radiation) tissue specimens [53][54][55]. Other studies with bacteria have investigated the effects of γ-radiation on Deinococcus radiodurans [56], Kocuria rosea [57]and Micrococcus luteus [58] with FTIR spectroscopy. Recently Gault et al have demonstrated the sensitivity of FTIR spectroscopy to apoptotic effects in γ-irradiated lymphocytes [59] and to molecular changes in HaCaT cells exposed to both γ-radiation and hydrogen peroxide [60], together with its sensitivity to biochemical alterations in HaCaT cells irradiated with α-particles delivered by micro-beams [61].…”