Vaios Nikolopoulos is a Biologist, MSc and a PhD candidate, has his expertise in molecular biology and diagnostics. His passion is to combine more aspects and functions of molecules and their pathways in order to see the big picture in a pathologic state either this is a cancerous process or diabetes etc. Currently, he is working in protein purification and ligand binding studies while studying crystallography and also elaborate with other colleagues in various clinical studies. His goal is to be a part of this “thinking tank” community to share his inquiring mind and to absorb new ideas in this highly competitive area of biosciences.
This work studies the relationship between the polymorphism Fok I VDR receptor gene of vitamin D, the low levels of vitamin D and the insulin resistance as risk factors for type-2 diabetes (DM2). Samples from 100 men and 101 women, aged 20 to 50 years, were collected of whole blood and serum during a fasting phase, autumn and winter of 2016 from Thessaloniki regional unit, Greece. All participants in this study were awarded and informed to consent in this research. We used PCR-RFLP in order to identify the genotype of vitamin D receptor. Glycemic markers, glucose, serum 25-hydroxyvitamin D [25(OH)D] and insulin levels was measured, while insulin resistance index HOMA-IR and body mass index (BMI) were calculated. Participants formed four groups based on levels of 25(OH)D. Groups includes less than 10 ng/ml to over than 30 ng/ml. Our findings indicate high percentage of vitamin D deficiency, especially among women in the age of 20-50 years old. The determination of HOMA-IR showed a statistically significant negative correlation with vitamin D and HOMA-IR. Individuals who experienced HOMA-IR of 1.90 to 2.90 were classified as having pre-diabetes and those who had more than 2.90 already suffering from DM-2. The study of Fok-I polymorphism of VDR receptor gene was found in the total sample percentages of genotypes FF 39.8%, Ff 37.31%, ff 22.89%. The ff genotype was increased in values less than 10 ng/ml, which is extremely worrying. The genotype is associated with the defective function of VDR, and in such cases administration of vitamin supplement could not help. In conclusion, the reduced vitamin D levels are more common to people who have the genotype ff. This is particularly important for our country because apart from low levels of vitamin D, there also are more frequently found the genotypes ff and Ff that are associated with defective function of vitamin D.
Inga Jamrozek obtained her BA Degree in Bioinformatics and MA Degree in Biotechnology from the University of Gdansk, Poland. She is currently a third year PhD student at the Intercollegiate Faculty of Biotechnology (IFB) of University of Gdansk (UG) and Medical University of Gdansk (MUG), Poland. Her major research interests lies in developing a model of GerA receptor and molecular mechanism of its function. This study is an interdisciplinary research conducted within Laboratory of Molecular Bacteriology at IFB of UG and MUG.
Statement of the Problem: Spores of Bacillus subtilis are extremely resistant to harsh environmental factors and can survive for years in their dormant state. However when the favorable conditions arise spores can rapidly lose their dormancy and resistance in the process of spore germination. Germination can be triggered by germinants – nutrients, that bind to a specific germination receptor (GR). One of such receptors, and the main interest of this study is GerA GR, which is composed of three subunits: GerAA, GerAB and GerAC, and is located in the spore inner membrane. Subunits A and B are predicted to be integral membrane proteins and responsible for germinants binding. However, till now there is no definitive knowledge describing the 3D structure of this receptors. Methodology: Models of GerA subunits were predicted using homology modeling approach, using Modeller program. Due to lack of close structural homolog GerAA and GerAB models were predicted using multitemplate modeling approach. Based on protein-protein interaction sites prediction, on biological assembly of templates used in homology modeling and on the similarity in the GRS clustering process to chemotaxis receptors clustering, we proposed that GerA subunits may form homodimers or homotrimers. Homocomplexes were predicted using protein-protein and symmetrical docking methods; using SAM program, ClusPro, ROSIE and GrammX servers. Proposed models of GerA receptor were built based on the protein-protein interaction sites prediction and using two approaches: molecular dynamics simulation in Amber package and a spontaneous proteins aggregation simulations. Models of GerA receptor were embedded into biological membrane model and optimized using the Martini force field. Findings & Significance: We were able to propose models of GerA germination receptor complex embedded into membrane model. Determination of GerA receptor structure and topology is an important step in study of the relationship of structure and function and mechanism of action of GerA receptor.