Jane Anastassopoulou

Metal-DNA Interactions

Metal ions can bind to DNA directly or indirectly through hydrogen bonding of the coordinating water molecules surrounding the metal ions. Metal binding to the bases usually disrupts base pair hydrogen bonding and destabilizes the double helix. Spectroscopic and X-ray data shows that the N7 atom of the purine or N3 of pyrimidine residues as well as exocyclic O atoms and the phosphate oxygen atoms are the preferential sites of metal binding. The binding of metals to DNA and RNA also influences indirectly the sugar conformation. As a result of this change in sugar puckering the two helical conformations of ADNA and B-DNA or RNA are characterized by the orientation of the bases with respect to the axis of the double helix. This may be the reason why some metal ions influence DNA synthesis and the replication process. In this paper we describe the influence of metal ion binding on the DNA structure and the variation of binding behaviour of different metal ions. q 2003 Elsevier Science B.V. All rights reserved.

Molecular modeling of azole antifungal agents active against Candida albicans. 1. A comparative molecular field analysis study.

A series of 56 azole antifungal agents belonging to chemically diverse families related to bifonazole, one of the antimycotic drugs of clinical use, were investigated using the comparative molecular field analysis (CoMFA) paradigm. The studied compounds, which have been already synthesized and reported to be active in vitro against Candida albicans, were divided into a training set and a test set. The training set consisted of 40 molecules from all the different structural classes. Due to the lack of experimental structural data on these derivatives, molecular mechanics techniques were used to obtain putative active conformations for all the compounds. the correctness of this molecular modeling work was confirmed a posteriori by comparison with structural data of the analog 2w obtained by X-ray crystallographic analysis (Massa, S.; et al. Eur. J. Med. Chem. 1992, 27, 495-502). Two different alignment rules of the training set molecules were used in this study and are based on the assumption that according to published results on azole antifungal agents, all the studied compounds exert their inhibitory activity through the coordination of their azole moiety to the protoporphyrin iron atom of the fungal lanosterol 14alpha-demethylase enzyme. The predictive ability of each resultant CoMFA model was evaluated using a test set consisting of 16 representative compounds that belong to all the different structural classes. The best 3D-quantitative structure-activity relationship model found yields significant cross-validated, conventional, and predictive r2 values equal to 0.57, 0.95, and 0.69, respectively. The average absolute error of predictions of this model is 0.30 log units, and the structural moieties of the studied antifungal agents which are thought to contribute to the biological activity were identified. The predictive capability of this model could be exploited in further synthetic studies on antifungal azoles. Furthermore, the results obtained by using two different alignments of the inhibitors suggest that the binding mode of these molecules involves both a coordination to the iron protoporphyrin atom and an additional, likewise relevant, hydrophobic interaction with the active site.

Mortality and pollution in several Greek cities.

This study examined the atmospheric pollution created by industry and traffic areas nearby the city of Kavala and the mortality of citizens in the region. The mortality data spanned over a period of 30 years. The statistical data on mortality was collected from 1968 to 1998. The causes of mortality analyzed in this study were cancer, cardiovascular deaths and pulmonary deaths. The results of this study were compared with other Greek cities. Air measurements were made over a period of 6 months and included levels of gaseous emissions as well as concentrations of Volatile Organic Compounds (VOCs), near the city of Kavala, where reservoirs of petroleum and exploitation of crude oil were present. Samples of air were collected from ambient surroundings near the industrial area and fuel oil facilities. The results obtained from the study indicated the presence of aromatic and aliphatic hydrocarbons and other gaseous pollutants such as, methane, o-, m-, p-xylene and ethylbenzene, etc. In some cases the levels exceeded the concentration limits specified by the air quality standards. Offensive odors were also detected (H2S). The study revealed that adverse environmental impact of air pollutants is a major concern in the industrial centers more than in the rural areas. This poses a threat to the public health and may induce disease and premature deaths. These air pollutants play an important role in air quality.

Supramolecular structure of certain amphiphilic liquid crystalline polymers

Abstract Poly(maleic anhydride) was reacted with long-chain aliphatic amines in a 1:1 molar ratio (as per monomer unit) resulting in the formation of amphiphilic polymers bearing the carboxylic group on their polymer backbone. On the other hand, poly(acryloyl chloride) was interacted with ω-amino or ω-hydroxy carboxylic acids affording polyamphiphiles with the carboxylic polar group at the tail of the pendant group. In addition, the carboxylic group was replaced by the extremely polar quaternary group at the end of the lipophilic chain. Liquid crystalline textures were exhibited by these polymers as determined by optical microscopy and d.s.c. studies while the supramolecular structures, formed through hydrogen bonding of carboxylic groups, were responsible for the formation of mesomorphic phases.

Raman studies of model vesicle systems

Raman spectroscopy has been used to study the paraffin-like side chain of lipids. Model molecules have been employed to study the interactions defining bilayer or vesicle reorganization as a function of concentration or vesicle temperature. It is known that vesicle structural and functional properties may be altered by lipid-lipid reorganization and single-compartment or multicompartment vesicle formation. The synthetic vesicles studied here are defined as smectic mesophases of completely synthetic surfactant bilayers containing entrapped water. Although many publications have documented the utilization of monolayers and bilayers, we believe that vesicle reorganization phenomena during polymerization of vesicles form an interesting process that deserves more study. Two synthetic vesicles—didodecyldimethylammonium bromide (DDAB), positively charged, and dihexadecylphosphate (DHP), negatively charged—both have a long chain of -CH2- groups extended from one end to the other in the multicompartment vesicle. DDAB is a quaternary ammonium salt of bromide with one end hydrophobic [{-(CH2)11-CH3}2] and the other end hydrophilic (-N+(CH3)2-), and DHP is a phosphate salt with one end hydrophobic [{(CH3-(CH2-)5O}2] and the other end hydrophilic (-PO2-).

Air pollution simulation and geographical information systems (GIS) applied to Athens International Airport

This study presents an improved methodology for analysing atmospheric pollution around airports using Gaussian-plume numerical simulation integrated with Geographical Information Systems (GIS). The new methodology focuses on streamlining the lengthy analysis process for Airport Environmental Impact Assessments by integrating the definition of emission sources, simulating and displaying the results in a GIS environment. One of the objectives of the research is to validate the methodology applied to the Athens International Airport, “Eleftherios Venizelos”, to produce a realistic estimate of emission inventories, dispersion simulations and comparison to measured data. The methodology used a combination of the Emission Dispersion and Modelling System (EDMS) and the Atmospheric Dispersion and Modelling system (ADMS) to improve the analysis process. The second objective is to conduct numerical simulations under various adverse conditions (e.g. scenarios) and assess the dispersion in the surrounding areas. The study concludes that the use of GIS in environmental assessments provides a valuable advantage for organizing data and entering accurate geographical/topological information for the simulation engine. Emissions simulation produced estimates within 10% of published values. Dispersion simulations indicate that airport pollution will affect neighbouring cities such as Rafina and Loutsa. Presently, there are no measured controls in these areas. In some cases, airport pollution can contribute to as much as 40% of permissible EU levels in VOCs.

Raman spectra and conformational analysis of long-methylene-chain-diamine—copper complexes

Solid powders of long methylene chain diamines NH2(CH2)nNH2 with n = 10, 12, and their newly synthesized copper complexes were studied by laser visible Raman spectroscopy. In this study, we mainly focus on the intensity variations of both the symmetrical and anti-symmetrical stretching vibrational modes of the CH2 groups situated in the high-frequency range 2800–3000 cm−1 and on the skeletal vibrations (C-C bonding) in the region 1050–1150 cm−1, which shows an unusual behaviour upon complexation of the diamines with the copper ion.

Fourier transform infrared spectroscopic studies of radiation-induced molecular changes in bone and cartilage

ABSTRACT Introduction: Ionizing radiation therapy is used as adjuvant, primary or palliative treatment of patients with primary tumors and metastatic bone disease. However, in cancer treatment, radiation also affects healthy tissues. IR spectroscopy can give important information on the behavior of radiation to bone structure. Areas covered: Radiation effects on matrix metabolism remain unclear, with a paucity of studies to identify the radiation effects at a molecular level. Spectroscopic studies have been prominent in the literature over the past two decades. In this article, we present our own data on the effect of radiation on the structure and properties of bone at a molecular level using FT-IR spectroscopy, correlate the data with the spectra and dose received, and discuss the related literature. Expert commentary: The interaction of cells with radiation results in enhanced production of free radicals leading to an alteration of the oxidative status and multiple cell damages. The products produced during radiation, free radicals and oxidative stress are similar to those during cancer development. The production of amyloid-proteins enhances the damage of radiation, while the hydrophilic environment inhibits the endogenous repairing mechanisms. The 1743 cm−1 band, attributed to malondialdehyde, can be used as ‘marker band’ for cancer progression.

Supramolecular Mg (II) Complexes of Cytosine and 1-Methylcytosine

The interaction of metal ions with nucleic acids has been a subject of study for many years[l,2]. The binding of magnesium to biological molecules, in cells, in the body, in plants and its role in many living processes is of great interest. In this paper we present some results on crystal structures of Mg2+ with nucleic constituents. Cytosine (Cyt) and 1-methylcytosine (1-Mecyt) were used as nucleic bases to interact with magnesium salts. Some of these complexes formed could be regarded as supermolecules.

Vibrational Spectroscopy of Certain Polymaleic- and Polyacrylic-Based Mesomorphic Polymers

The FT-IR/ATR technique has been employed in the investigation of the forces leading to the organization of a number of polymeric materials exhibiting thermotropic liquid crystalline character. Two types of compounds have been studied, i.e., one bearing the carboxylic polar group near the main chain and the other at the end of the side chain. Intermolecular and intramolecular hydrogen bonding between the carboxylic groups was found to lead to the formation of “facing” and “sideways” structures. Enhanced stability of these supramolecular structures was obtained by the presence of intramolecular hydrogen bonds between the amide groups, resulting in the formation of smectic phases. Furthermore, it has been found that the strengthening of hydrogen bonding between carboxylic groups is associated with a weakening of hydrogen bonds between the amide groups.