An FTIR Microspectroscopy Ratiometric Approach for Monitoring X-ray Irradiation Effects on SH-SY5Y Human Neuroblastoma Cells

Bio-spectroscopic analysis of corneal structural alterations in dry eye disease: A study of collagen, co-enzymes, lipids, and proteins with emphasis on phytotherapy intervention

Dry eye disease (DED) stands as a prevalent cause for ophthalmology consultations, securing the third position following refractive errors and cataracts. Moreover, the likelihood of experiencing DED escalates with advancing age. In this experimental study corneal tissue alterations due to DED were investigated over different periods by applying both infrared and synchronous fluorescence spectroscopy. The potential effects of instillation of pomegranate and green tea water extracts as green-friendly treatment modalities were also evaluated. The obtained results collectively indicate that DED affects the OH bearing constituents (collagen, glycosaminoglycans, and proteoglycans) of cornea leading to changes in protein secondary structure and the collagen fibrils. Additionally, enhanced dehydrated environment, and reduced energetic/metabolic state, as indicated by co-enzymes, was observed. Phyto-therapeutic administration can contain these alterations with enhanced energetic/metabolic state and increased hydration environment. In conclusion, instillation of green tea extract can protect/restore the collagen fibrils and its potential effects, in general, exceeds that of pomegranate extract.

Bio-spectroscopic investigation linking changes of retinal structure with short-term administration of Amiodarone and revealing the ameliorative effect of vitamin E supplementation

Long term use of Amiodarone (AMIO) is associated with the development of ocular adverse effects. This study investigates the short term effects, and the ameliorative consequence of vitamin E on retinal changes that were associated with administration of AMIO. This is accomplished by investigating both retinal structural and conformational characteristics using Fourier transform infrared spectroscopy (FTIR) and Fundus examination. Three groups of healthy rabbits of both sexes were used; the first group served as control. The second group was orally treated with AMIO (160 mg /kg body weight) in a daily basis for two weeks. The last group orally received AMIO as the second group for two weeks then, oral administration of vitamin E (100 mg/kg body weight) for another two weeks as well. FTIR results revealed significant structural and conformational changes in retinal tissue constituents that include lipids and proteins due to AMIO administration. AMIO treatment was associated with fluctuated changes (increased/decreased) in the band position and bandwidth of NH, OH, and CH bonds. This was concomitant with changes in the percentage of retinal protein constituents in particularly α-helix and Turns. AMIO facilitates the formation of intra-molecular hydrogen bonding and turned retinal lipids to be more disordered structure. In conclusion, the obtained FTIR data together with principal component analysis provide evidence that administration of vitamin E following the treatment with AMIO can ameliorate these retinal changes and, these biophysical changes are too early to be detected by Fundus examination.

The impact of photoreceptor layer loss on different ocular tissues: Insights from FTIR spectroscopy

Photoreceptor loss has significant consequences for visual function, and its management is a critical component for treating not only retinal diseases such as age-related macular degeneration and retinitis pigmentosa but also its ocular consequences. On the other hand, Fourier transform infrared spectroscopy is an excellent tool to investigate molecular structure and dynamics of biological samples, and as a non-destructive and label free measurement, it does not perturb the samples. In this study, detailed analyses of the recorded FTIR spectra from cornea, lens and sclera were performed to monitor the distribution of ocular abnormalities due to photoreceptor layer loss after 1, 3 and 6 days. FTIR data were statistically evaluated by multivariate analysis and Bonferroni means comparison. The obtained results revealed that ocular abnormalities associated with photoreceptor layer loss are varied among the investigated tissues, and comprise changes in both hydrogen bond network around proteins and lipid disorder. Structural modifications of protein secondary structure were reported in all investigated tissues. Clinically, the concluded information from FTIR data and its statistical evaluation can contribute to the development of therapeutic strategies for these heterogeneous changes.

Long-term, non-invasive FTIR detection of low-dose ionizing radiation exposure

Non-invasive methods of detecting radiation exposure show promise to improve upon current approaches to biological dosimetry in ease, speed, and accuracy. Here we developed a pipeline that employs Fourier transform infrared (FTIR) spectroscopy in the mid-infrared spectrum to identify a signature of low dose ionizing radiation exposure in mouse ear pinnae over time. Mice exposed to 0.1 to 2 Gy total body irradiation were repeatedly measured by FTIR at the stratum corneum of the ear pinnae. We found significant discriminative power for all doses and time-points out to 90 days after exposure. Classification accuracy was maximized when testing 14 days after exposure (specificity > 0.9 with a sensitivity threshold of 0.9) and dropped by roughly 30% sensitivity at 90 days. Infrared frequencies point towards biological changes in DNA conformation, lipid oxidation and accumulation and shifts in protein secondary structure. Since only hundreds of samples were used to learn the highly discriminative signature, developing human-relevant diagnostic capabilities is likely feasible and this non-invasive procedure points toward rapid, non-invasive, and reagent-free biodosimetry applications at population scales.

Exploring the cellular surface polysaccharide and root nodule symbiosis characteristics of the rpoN mutants of Bradyrhizobium sp. DOA9 using synchrotron-based Fourier transform infrared microspectroscopy in conjunction with X-ray absorption spectroscopy

The functional significance of rpoN genes that encode two sigma factors in the Bradyrhizobium sp. strain DOA9 has been reported to affect colony formation, root nodulation characteristics, and symbiotic interactions with Aeschynomene americana. rpoN mutant strains are defective in cellular surface polysaccharide (CSP) production compared with the wild-type (WT) strain, and they accordingly exhibit smaller colonies and diminished symbiotic effectiveness. To gain deeper insights into the changes in CSP composition and the nodules of rpoN mutants, we employed synchrotron-based Fourier transform infrared (SR-FTIR) microspectroscopy and X-ray absorption spectroscopy. FTIR analysis of the CSP revealed the absence of specific components in the rpoN mutants, including lipids, carboxylic groups, polysaccharide-pyranose rings, and β-galactopyranosyl residues. Nodules formed by DOA9WT exhibited a uniform distribution of lipids, proteins, and carbohydrates; mutant strains, particularly DOA9∆rpoNp:ΩrpoNc, exhibited decreased distribution uniformity and a lower concentration of C=O groups. Furthermore, Fe K-edge X-ray absorption near-edge structure and extended X-ray absorption fine structure analyses revealed deficiencies in the nitrogenase enzyme in the nodules of DOA9∆rpoNc and DOA9∆rpoNp:ΩrpoNc mutants; nodules from DOA9WT and DOA9∆rpoNp exhibited both leghemoglobin and the nitrogenase enzyme. IMPORTANCE This work provides valuable insights into how two rpoN genes affect the composition of cellular surface polysaccharides (CSPs) in Bradyrhizobium sp., which subsequently dictates root nodule chemical characteristics and nitrogenase production. We used advanced synchrotron methods, including synchrotron-based Fourier transform infrared (SR-FTIR) microspectroscopy and X-ray absorption spectroscopy (XAS), for the first time in this field to analyze CSP components and reveal the biochemical changes occurring within nodules. These cutting-edge techniques confer significant advantages by providing detailed molecular information, enabling the identification of specific functional groups, chemical bonds, and biomolecule changes. This research not only contributes to our understanding of plant-microbe interactions but also establishes a foundation for future investigations and potential applications in this field. The combined use of the synchrotron-based FTIR and XAS techniques represents a significant advancement in facilitating a comprehensive exploration of bacterial CSPs and their implications in plant-microbe interactions.

Biomolecular alterations detected in multiple sclerosis skin fibroblasts using Fourier transform infrared spectroscopy

Multiple sclerosis (MS) is the leading cause of non-traumatic disability in young adults. New avenues are needed to help predict individuals at risk for developing MS and aid in diagnosis, prognosis, and outcome of therapeutic treatments. Previously, we showed that skin fibroblasts derived from patients with MS have altered signatures of cell stress and bioenergetics, which likely reflects changes in their protein, lipid, and biochemical profiles. Here, we used Fourier transform infrared (FTIR) spectroscopy to determine if the biochemical landscape of MS skin fibroblasts were altered when compared to age- and sex-matched controls (CTRL). More so, we sought to determine if FTIR spectroscopic signatures detected in MS skin fibroblasts are disease specific by comparing them to amyotrophic lateral sclerosis (ALS) skin fibroblasts. Spectral profiling of skin fibroblasts from MS individuals suggests significant alterations in lipid and protein organization and homeostasis, which may be affecting metabolic processes, cellular organization, and oxidation status. Sparse partial least squares-discriminant analysis of spectral profiles show that CTRL skin fibroblasts segregate well from diseased cells and that changes in MS and ALS may be unique. Differential changes in the spectral profile of CTRL, MS, and ALS cells support the development of FTIR spectroscopy to detect biomolecular modifications in patient-derived skin fibroblasts, which may eventually help establish novel peripheral biomarkers.

Vibrational spectroscopies for biochemical investigation of X-ray exposure effects on SH-SY5Y human neuroblastoma cells

Neuroblastoma is the most recurring cancer in childhood and adolescence. The SH-SY5Y neuroblastoma cell line is generally adopted for elaborating new therapeutical approaches and/or elaborating strategies for the prevention of central nervous system disturbances. In fact, it represents a valid model system for investigating in vitro the effects on the brain of X-ray exposure using vibrational spectroscopies that can detect early radiation-induced molecular alterations of potential clinical usefulness. In recent years, we dedicated significant efforts in the use of Fourier-transform and Raman microspectroscopy techniques for characterizing such radiation-induced effects on SH-SY5Y cells by examining the contributions from different cell components (DNA, proteins, lipids, and carbohydrates) to the vibrational spectra. In this review, we aim at revising and comparing the main results of our studies to provide a wide outlook of the latest outcomes and a framework for future radiobiology research using vibrational spectroscopies. A short description of our experimental approaches and data analysis procedures is also reported.

A Brief Review of FT-IR Spectroscopy Studies of Sphingolipids in Human Cells

In recent years, sphingolipids have attracted significant attention due to their pivotal role in cellular functions and physiological diseases. A valuable tool for investigating the characteristics of sphingolipids can be represented via FT-IR spectroscopy, generally recognized as a very powerful technique that provides detailed biochemical information on the examined sample with the unique properties of sensitivity and accuracy. In the present paper, some fundamental aspects of sphingolipid components of human cells are summarized, and the most relevant articles devoted to the FT-IR spectroscopic studies of sphingolipids are revised. A short description of different FT-IR experimental approaches adopted for investigating sphingolipids is also given, with details about the most commonly used data analysis procedures. The present overview of FT-IR investigations, although not exhaustive, attests to the relevant role this vibrational technique has played in giving significant insight into many aspects of this fascinating class of lipids.

X-rays induced alterations in mechanical and biochemical properties of isolated SH-SY5Y nuclei

BACKGROUND

The use of ionizing radiations in radiotherapy is an effective and very common cancer treatment after surgery. Although ionizing-radiation DNA damages are extensively investigated, little is known about their effects on the other nuclear components, since their variations when studied in whole cells can be difficult to decouple from those of the cytoplasmatic structures. The organization of nuclear components plays a functional role since they are directly involved in some of the nuclear response to chemical or physical stimuli. For this reason, studying the X-ray effects on nuclear components is a crucial step in radiobiology.

MATERIALS AND METHODS

We have used Atomic Force Microscopy (AFM) and micro-FTIR to examine the biomechanical and biochemical properties of hydrated fixed nuclei isolated from neuroblastoma (SH-SY5Y) cells irradiated by 2, 4, 6 and 8 Gy X-ray doses.

RESULTS

The experimental results have shown that, already at 2 Gy irradiation dose, the nuclei exhibit not only a DNA damage, but also relevant alterations of lipid saturation, protein secondary structure arrangement and a significant decrease in nuclear stiffness, which indicate a remarkable chromatin decondensation.

CONCLUSIONS AND GENERAL SIGNIFICANCE

The present work demonstrates that a multi-technique approach, able to disclose multiple features, can be helpful to achieve a comprehensive picture of the X-ray irradiation effects of the nuclear components and distinguish them from those occurring at the level of cytoplasm.

Fourier Transform Infrared Spectroscopy (FT-IR) of Pseudomonas aeruginosa post photodynamic therapy with Curcumin in vitro

Alternative therapies against pathogens are under intense investigation because of their increasing resistance to antibiotics. Photodynamic therapy (PDT) is one such alternative that has shown promising results. However, for the widespread use of PDT, it is essential to decipher underlying mechanisms, so as to improve PDT's therapeutic applications. Because of this, we have studied biochemical changes in pathogen Pseudomonas aeruginosa, a medically important bacteria that has developed antibiotic resistance, after PDT with curcumin photosensitizer. Results show a drastic decrease in α-helix protein and increased disordered and β-sheet secondary structure proteins in P. Aeruginosa post-PDT compared to control. Interestingly, these biochemical changes differ from PDT of pathogens Leishmania braziliensis and Leishmania major with photosensitizer methylene blue. This observation underlines the need for extensive studies on PDT of different pathogens to understand mechanisms of action and develop better PDT strategies.

Evaluation of Proteomic and Lipidomic Changes in Aeromonas-Infected Trout Kidney Tissue with the Use of FT-IR Spectroscopy and MALDI Mass Spectrometry Imaging

Aeromonas species are opportunistic bacteria causing a vast spectrum of human diseases, including skin and soft tissue infections, meningitis, endocarditis, peritonitis, gastroenteritis, and finally hemorrhagic septicemia. The aim of our research was to indicate the molecular alterations in proteins and lipids profiles resulting from Aeromonas sobria and A. salmonicida subsp. salmonicida infection in trout kidney tissue samples. We successfully applied FT-IR (Fourier transform infrared) spectroscopy and MALDI-MSI (matrix-assisted laser desorption/ionization mass spectrometry imaging) to monitor changes in the structure and compositions of lipids, secondary conformation of proteins, and provide useful information concerning disease progression. Our findings indicate that the following spectral bands’ absorbance ratios (spectral biomarkers) can be used to discriminate healthy tissue from pathologically altered tissue, for example, lipids (CH2/CH3), amide I/amide II, amide I/CH2 and amide I/CH3. Spectral data obtained from 10 single measurements of each specimen indicate numerous abnormalities concerning proteins, lipids, and phospholipids induced by Aeromonas infection, suggesting significant disruption of the cell membranes. Moreover, the increase in the content of lysolipids such as lysophosphosphatidylcholine was observed. The results of this study suggest the application of both methods MALDI-MSI and FT-IR as accurate methods for profiling biomolecules and identifying biochemical changes in kidney tissue during the progression of Aeromonas infection.

Conjugation of Ctx(Ile21)-Ha Antimicrobial Peptides to Chitosan Ultrathin Films by N-Acetylcysteine Improves Peptide Physicochemical Properties and Enhances Biological Activity

The importance of obtaining new compounds with improved antimicrobial activity is a current trend and challenge. Some polymers such as chitosan have shown promising bactericidal properties when they are structurally modified, which is due to the binding versatility provided by their free amines. Likewise, antimicrobial peptides (AMPs) have received attention in recent years because of their bactericidal activity that is similar to or even better than that of conventional drugs, and they exhibit a low induction rate of antimicrobial resistance. Herein, the modified AMP Ctx(Ile²¹)-Ha-Ahx-Cys was conjugated to chitosan using N-acetylcysteine as an intermediate by the carbodiimide method. Films were prepared using protonated chitosan in 1% acetic acid and Ctx(Ile²¹)-Ha-Ahx-Cys AMP dissolved in N-acetylcysteine-chitosan; 1.6 mmol of ethylcarbodiimide hydrochloride, 1.2 mmol of N-hydroxysulfosucchimide, and 0.1 mol L ^-1of N-morpholino)ethanesulfonic acid buffer at pH 6.5 by continuous stirring at 100 × g for 10 min at 37 °C. Physicochemical properties were evaluated by Fourier-transform infrared spectroscopy, differential scanning calorimetry/thermogravimetric analysis, and X-ray diffraction to determine the mechanical properties, solubility, morphology, and thickness. Furthermore, the antimicrobial activities of chitosan-based conjugated films were evaluated againstStaphylococcus aureus,Pseudomonas aeruginosa,SalmonellaTyphimurium, andEscherichia coli. The results showed that the conjugation of a potent AMP could further increase its antibacterial activity and maintain its stable physicochemical properties. Therefore, the developed peptide-chitosan conjugate could be applied as an additive in surgical procedures to prevent and combat bacterial infection.

Evaluation of Proton-Induced Biomolecular Changes in MCF-10A Breast Cells by Means of FT-IR Microspectroscopy

Radiotherapy (RT) with accelerated beams of charged particles (protons and carbon ions), also known as hadrontherapy, is a treatment modality that is increasingly being adopted thanks to the several benefits that it grants compared to conventional radiotherapy (CRT) treatments performed by means of high-energy photons/electrons. Hence, information about the biomolecular effects in exposed cells caused by such particles is needed to better realize the underlying radiobiological mechanisms and to improve this therapeutic strategy. To this end, Fourier transform infrared microspectroscopy (μ-FT-IR) can be usefully employed, in addition to long-established radiobiological techniques, since it is currently considered a helpful tool for examining radiation-induced cellular changes. In the present study, MCF-10A breast cells were chosen to evaluate the effects of proton exposure using μ-FT-IR. They were exposed to different proton doses and fixed at various times after exposure to evaluate direct effects due to proton exposure and the kinetics of DNA damage repair. Irradiated and control cells were examined in transflection mode using low-e substrates that have been recently demonstrated to offer a fast and direct way to examine proton-exposed cells. The acquired spectra were analyzed using a deconvolution procedure and a ratiometric approach, both of which showed the different contributions of DNA, protein, lipid, and carbohydrate cell components. These changes were particularly significant for cells fixed 48 and 72 h after exposure. Lipid changes were related to variations in membrane fluidity, and evidence of DNA damage was highlighted. The analysis of the Amide III band also indicated changes that could be related to different enzyme contributions in DNA repair.

Evaluation by MALDI-TOF MS and PCA of the diversity of biosurfactants and their producing bacteria, as adaption to weathered oil components

Indigenous Qatari bacterial strains were isolated from highly weathered oil-contaminated sites, identified, and differentiated based on their protein profiles using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Their diversity was demonstrated by the principal component analysis (PCA) analysis and establishment of a proteodendogram. Both were based on the protein profile of each strain. Interestingly, this approach also showed diversity within the same subspecies. This high diversity is reflected in the emulsification and solubilization activities of their extracellular biosurfactants. The highest emulsification activity (42.1 ± 2.11 AU/mL) was obtained with a strain of Lysinibacillus fusiformis (SA4) after one week of growth in the minimum salt medium in which diesel (5%) is the sole carbon source, while the highest solubilization activity (9.47% ± 0.47%) was produced by the strain Bacillus subtilis (SA6). The functional diversity of the biosurfactants was demonstrated by PCA analysis which allowed their further clustering based on the Fourier-transform infrared spectroscopy (FTIR) analysis. These findings clearly showed that two types of adaptations occur with hydrocarbons degrading bacteria in the weathered-oily soils, one related to the bacterial cell composition maintaining the biosurfactants composition and one to the biosurfactants, which are the primary tool employed by the cell to interact with the weathered oil. This finding would shed light on the potential and strategies of applications for the bioremediation of highly weathered oil-contaminated soils.

Radiation-Induced Effect on Spin-Selective Electron Transfer through Self-Assembled Monolayers of ds-DNA

Stability of the DNA molecule is essential for the proper functioning and sustainability of all living organisms. In this study, we investigate the effect of gamma radiation (γ-radiation) on spin-selective electron transfer through double strand (ds)DNA molecules. Self-assembled monolayers (SAMs) of 21-base long DNA are prepared on Au-coated Ni thin film. We measure the spin polarization (%) of the SAMs of ds-DNA using the spin-dependent electrochemical technique. We use a Cs-based γ-radiation source to expose the SAMs of ds-DNA immobilized on thin films for various time intervals ranging from 0–30 min. The susceptibility of DNA to γ-radiation is measured by spin-dependent electrochemistry. We observe that the efficiency of spin filtering by ds-DNA gradually decreases when exposure (to γ-radiation) time increases, and drops below 1% after 30 min of exposure. The change in spin polarization value is related either to the conformational perturbation in DNA or to structural damage in DNA molecules caused by ionizing radiation.

FT-IR Transflection Micro-Spectroscopy Study on Normal Human Breast Cells after Exposure to a Proton Beam

Fourier transform infrared micro-spectroscopy (μ-FT-IR) is nowadays considered a valuable tool for investigating the changes occurring in human cells after exposure to ionizing radiation. Recently, considerable attention has been devoted to the use of this optical technique in the study of cells exposed to proton beams, that are being increasingly adopted in cancer therapy. Different experimental configurations are used for proton irradiation and subsequent spectra acquisition. To facilitate the use of μ-FT-IR, it may be useful to investigate new experimental approaches capable of speeding up and simplifying the irradiation and measurements phases. Here, we propose the use of low-e-substrates slides for cell culture, allowing the irradiation and spectra acquisition in transflection mode in a fast and direct way. In recent years, there has been a wide debate about the validity of these supports, but many researchers agree that the artifacts due to the presence of the electromagnetic standing wave effects are negligible in many practical cases. We investigated human normal breast cells (MCF-10 cell line) fixed immediately after the irradiation with graded proton radiation doses (0, 0.5, 2, and 4 Gy). The spectra obtained in transflection geometry showed characteristics very similar to those present in the spectra acquired in transmission geometry and confirm the validity of the chosen approach. The analysis of spectra indicates the occurrence of significant changes in DNA and lipids components of cells. Modifications in protein secondary structure are also evidenced.