The role of water in the behaviour of biomolecules is well recognized. The coupling of motions between water and biomolecules has been studied in a wide time scale for the self part while collective dynamics is still quite unexplored. Self-dynamics provides information about the diffusion processes of water molecules and relaxation processes of the protein structure. Collective density fluctuations might provide important insight on the transmission of information possibly correlated to biological functionality. The idea that hydration water layers surrounding a biological molecule show a self-dynamical signature that differs appreciably from that of bulk water, in analogy with glass-former systems, is quite accepted. In the same picture Brillouin terahertz spectroscopy has been used to directly probe collective dynamics of hydration water molecules around biosystems, showing a weaker coupling and a more bulklike behaviour. We will discuss results of collective modes of hydration water, arising from neutron Brillouin spectroscopy, in the context of biomolecules-solvent interaction.

D. Russo

A. Orecchini

A. De Francesco

F. Formisano

A. Laloni

C. Petrillo

F. Sacchetti

Brillouin Neutron Spectroscopy as a Probe to Investigate Collective Density Fluctuations in Biomolecules Hydration Water

Fungi are considered as serious pathogens for many plants, potentially causing severe economic damage. Early detection and identification of these pathogens is crucial for their timely control. The methods available for identification of fungi are time consuming and not always very specific. In this study, the potential of FTIR-ATR spectroscopy was examined together with advanced mathematical principle component analysis (PCA) and statistical linear discriminant analysis (LDA) to differentiate among 10 isolates of Fusarium oxysporum. The results are encouraging and indicate that FTIR-ATR can successfully detect different isolates of Fusarium oxysporum. Based on PCA and LDA calculations in the region 850–1775 cm-1 with 16 PC's, the different strains from the same fungal genus could be classified with 75.3% and 69.5% success rates using the “leave one out” method and “20–80% algorithm” respectively.

A. Salman

I. Lapidot

A. Pomerantz

L. Tsror

Z. Hammody

R. Moreh

M. Huleihel

S. Mordechai

Detection of Fusarium oxysporum Fungal Isolates Using ATR Spectroscopy

The light-driven disassembly process of amyloid-like structures formed by azobenzene model peptides is studied by time-resolved mid-IR spectroscopy from nanoseconds to minutes. The investigated peptide consists of two amino acid strands connected by the azobenzene switch. The peptides aggregate to amyloid-like structures when the azobenzene chromophore is in the trans-conformation. Illumination, resulting in a trans- to cis-isomerization of the azobenzene, leads to disaggregation of the aggregated structures. After optical excitation and isomerization of the azobenzene, one finds absorption changes which recover to a large extent on the time scale of few nanoseconds. These early absorption transients are assigned to the relaxation of vibrational excess energy (heat) or to structural rearrangements of isomerized azobenzene and the aggregated surroundings. It is only on the time scale of minutes that spectral signatures appear which are characteristic for the disassembly of the aggregated structure.

Andreas A. Deeg

Tobias E. Schrader

Halina Strzalka

Jose Pfizer

Luis Moroder

Wolfgang Zinth

Amyloid-Like Structures Formed by Azobenzene Peptides: Light-Triggered Disassembly

Rapid and reproducible discrimination between bacterial pathogens is a clear goal in microbiological laboratories when processing infected clinical samples. In this study Raman spectra were taken from at least 30 colonies of four strains of bacteria including Staphylococcus epidermidis (1457 and 9142) and Escherichia coli (K12 and Top 10) using the Renishaw in Via Raman microscope system. Analysis based on principal components suggests that even strain differentiation (e.g., 1457 versus 9142 or K12 versus Top10) is possible.

Jamal F. M. Almarashi

Natalia Kapel

Thomas S. Wilkinson

Helmut H. Telle

Raman Spectroscopy of Bacterial Species and Strains Cultivated under Reproducible Conditions

We have introduced a new promising approach for the determination of pKa constants of oligopeptide intrinsic fluorophores and spectral components referring to their differently charged states. The method is based on the factor analysis of multiwavelength spectroscopic pH titration data. As an illustration, we present its application on the study of short segments of the MADS box, which is a highly conserved sequence of a so-called family of transcription factors, by techniques of UV absorption and fluorescence spectroscopies. Investigated oligopeptides contain no tryptophan but one tyrosine serving as an intrinsic fluorophore and absorber. The results indicate both good sensitivity and spectroscopic selectivity of our method, which thus may be considered as a complementary technique to conventional electrochemical methods.

Barbora &#x158;ez&#xE1;&#x10d;ov&#xE1;

Yves-Marie Coïc

Christian Zentz

Pierre-Yves Turpin

Josef Št&#x011B;pánek

Spectroscopic Determination of pKa Constants of MADS Box Segments

Halictine-1 (Hal-1)—a linear antibacterial dodecapeptide isolated from the venom of the eusocial bee Halictus sexcinctus—has been subjected to a detailed spectroscopic study including circular dichroism, fluorescence, and vibrational spectroscopy. We investigated Hal-1 ability to adopt an amphipathic α-helical structure upon interaction with model lipid-based bacterial membranes (phosphatidylcholine/phosphatidylglycerol-based large unilamellar vesicles and sodium dodecylsulfate micelles) and helix inducing components (trifluoroethanol). It was found that Hal-1 responds sensitively to the composition of the membrane model and to the peptide/lipid ratio. The amphipathic nature of the helical Hal-1 seems to favour flat charged surfaces of the model lipid particles over the nondirectional interaction with trifluoroethanol. Increasing fraction of polyproline II type conformation was detected at low peptide/lipid ratios.

Markéta Pazderková

Eva Ko&#x10d;i&#x161;ov&#xE1;

Tomáš Pazderka

Petr Malo&#x0148;

Vladimír Kopecký Jr.

Lenka Monincová

Václav &#x010C;e&#x0159;ovský

Lucie Bednárová

Antimicrobial Peptide from the Eusocial Bee Halictus sexcinctus Interacting with Model Membranes

In biomedical and food industry, surface colonization by bacteria is harmful: it leads to biofilm formation, a microbial consortia more resistant to antibiotics than planktonic bacteria. In order to design materials able to limit the biofilm formation, the effect of bacteria on materials has to be well characterized. In this work, a well-defined surface composed of a self-assembled monolayer (SAM) of octadecanethiol (ODT) onto a gold surface is probed in situ. The SAM conformation is obtained using the femtosecond vibrational sum frequency generation (SFG) spectroscopy. This technique provides selectively the molecular vibrational signature of the interface. The behaviour of the ODT SAM is studied in different environments: in air, in water, and upon exposure to hydrophilic or hydrophobic Lactococcus lactis bacteria. Modelling the experimental SFG spectra reveals a measurable change of the SAM conformation which depends on the environment, especially on the hydrophilic-hydrophobic character.

Emilie Bulard

Marie-Pierre Fontaine-Aupart

Henri Dubost

Wanquan Zheng

Jean-Marie Herry

Marie-No&#xeb;lle Bellon-Fontaine

Romain Briandet

Bernard Bourguignon

The Effect of Bacterial Adhesion on Grafted Chains Revealed by the Non-Invasive Sum Frequency Generation Spectroscopy

The interaction of the linker histone H1Z from the sperm chromatin of starfish Asterias amurensis with DNA was studied by spectroscopic and thermodynamic approaches. It has been shown that at the physiological conditions the interaction of the H1Z with DNA results in more compact structures compared to complexes of DNA with somatic histone H1. The typical profile of the DNA melting curves reveals two peaks attributed to the bound and unbound DNA. It has been shown that H1Z from starfish sperm stabilizes DNA to a greater extent compared to the somatic H1. It is possible that the presence of the additional α—helical segments within the C-terminal part of the H1Z typical for the linker histones from echinoderm sperm facilitates the protein-protein interactions which in turn stimulate cooperative binding of the histones to DNA, resulting in the formation of the supercompact sperm chromatin.

Elena Chikhirzhina

Tatyana Starkova

Elena Kostyleva

Alexander Polyanichko

Spectroscopic Study of the Interaction of DNA with the Linker Histone H1 from Starfish Sperm Reveals Mechanisms of the Formation of Supercondensed Sperm Chromatin

A conformational analysis of the Pt(dap)Cl2 complex (<svg style="vertical-align:-2.72116pt;width:64.224998px;" id="M1" height="14.1875" version="1.1" viewBox="0 0 64.224998 14.1875" width="64.224998" xmlns="http://www.w3.org/2000/svg">
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			</svg>-diaminopropane) was performed by vibrational spectroscopy (FTIR, Raman, and INS), coupled to quantum mechanical methods within the density functional theory (DFT) and effective core potential (ECP) approaches. A complete spectral assignment of the system was achieved, due to the combined use of all available vibrational spectroscopic techniques. A good agreement was found between experimental and theoretical results, as well as with reported data for analogous complexes (e.g., cisplatin).

Ana L. M. Batista de Carvalho

S&#xf3;nia M. Fiuza

John Tomkinson

Lu&#xed;s A. E. Batista de Carvalho

M. Paula M. Marques

Pt(II) Complexes with Linear Diamines&#x2014;Part I: Vibrational Study of Pt-Diaminopropane

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Journal of Spectroscopy publishes research into the theory and application of spectroscopy across all disciplines, including biology, chemistry, engineering, earth sciences, medicine, materials science, physics, and space science.

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Chief Editor&nbsp;Dr Daniel Cozzolino&nbsp;is based at the University of Queensland, Australia. His research focuses on the developments of chemometric and spectroscopic methods for use in agriculture and food applications.

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Journal of Spectroscopy publishes research into the theory and application of spectroscopy across all disciplines, including biology, chemistry, engineering, earth sciences, medicine, materials science, physics, and space science.

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Journal of Spectroscopy

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Maria Marques

Luis de Carvalho

Parvez Haris