Publications by authors named "Stavroula Fili"

Hydroponic-based systems for plant growth allow control of the nutrients that plants take up through the provided nutrient solution. Different formulations of nutrient solutions enable the study of nutrient deficiencies in plants. Here we describe a procedure for setting up a simple semi-hydroponic system to grow maize seedlings.

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The polymorphism of human insulin upon pH variation was characterized via X-ray powder diffraction, employing a crystallization protocol previously established for co-crystallization with phenolic derivatives. Two distinct rhombohedral (R3) polymorphs and one cubic (I23) polymorph were identified with increasing pH, corresponding to the T, TR and T conformations of insulin, respectively. The structure of the cubic T polymorph was determined via multi-profile stereochemically restrained Rietveld refinement at 2.

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Advances in instrumentation, as well as the development of powerful crystallographic software have significantly facilitated the collection of high-resolution diffraction data and have made X-ray powder diffraction (XRPD) particularly useful for the extraction of structural information; this is true even for complex molecules, especially when combined with synchrotron radiation. In this study, in-line with past instrumental profile studies, an improved data collection strategy exploiting the MYTHEN II detector system together with significant beam focusing and tailored data collection options was introduced and optimized for protein samples at the Material Science beamline at the Swiss Light Source. Polycrystalline precipitates of octreotide, a somatostatin analog of particular pharmaceutical interest, were examined with this novel approach.

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Natural or artificially manufactured peptides attract scientific interest worldwide owing to their wide array of pharmaceutical and biological activities. X-ray structural studies are used to provide a precise extraction of information, which can be used to enable a better understanding of the function and physicochemical characteristics of peptides. Although it is vulnerable to disassociation, one of the most vital human peptide hormones, somatostatin, plays a regulatory role in the endocrine system as well as in the release of numerous secondary hormones.

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In this study, the first crystal structure of a novel crystal form of human insulin bound to meta-cresol in an acidic environment is reported. The combination of single-crystal and powder X-ray diffraction crystallography led to the detection of a previously unknown monoclinic phase (P2). The structure was identified from the powder patterns and was solved using single-crystal diffraction data at 2.

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Human insulin (HI) is a well-characterized natural hormone which regulates glycose levels into the blood-stream and is widely used for diabetes treatment. Numerous studies have manifested that despite significant efforts devoted to structural characterization of this molecule and its complexes with organic compounds (ligands), there is still a rich diagram of phase transitions and novel crystalline forms to be discovered. Towards the improvement of drug delivery, identification of new insulin polymorphs from polycrystalline samples, simulating the commercially available drugs, is feasible today via macromolecular X-ray powder diffraction (XRPD).

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Viral proteases are proteolytic enzymes that orchestrate the assembly of viral components during the viral life cycle and proliferation. Here, the expression, purification, crystallization and preliminary X-ray diffraction analysis are presented of protease 3C, the main protease of an emerging enterovirus, coxsackievirus B3, that is responsible for many cases of viral myocarditis. Polycrystalline protein precipitates suitable for X-ray powder diffraction (XRPD) measurements were produced in the presence of 22-28%(w/v) PEG 4000, 0.

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