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Mitochondrial 2-oxoglutarate dehydrogenase complex (2-OGDH) that consists of multiple copies of 3 catalytic subunits (E1, E2, E3) is a regulatory enzyme of tricarboxylic acid cycle. 2-OGDH together with branched chain α-ketoacid dehydrogenase (BCKDH) and pyruvate dehydrogenase (PDH) belongs to the 2-oxoacid dehydrogenases family. It was shown that in protein-restricted rats simvastatin stimulated liver BCKDH, whereas it exerted no effect on BCKDH in rats fed a standard diet. We hypothesized that combination of simvastatin and low-protein diet could have an impact on renal 2-OGDH. The purpose of the study was to determine the effect of combination of simvastatin and low-protein diet on renal 2-OGDH in rats. Simvastatin (80 mg/kg b.wt/day) or the vehicle (0.3% methylcellulose) were administered orally (for 14 days) to rats fed low-protein (8% protein) or standard (23% protein) diet. 2-OGDH activity, protein levels and mRNA levels for E1 and E2 subunits were determined. In addition, serum creatinine level was measured. Results: The combination of simvastatin and low-protein diet elicited the increase of renal 2-OGDH activity that corresponded to the increase of E1 protein, but not of E1 mRNA level. In contrast, simvastatin treatment did not affect 2-OGDH activity, nor protein and mRNA levels of E1 in rats fed standard diet. Serum creatinine levels were not changed upon simvastatin administration in any group. In conclusion, the results of present study indicate that combination of simvastatin and low-protein diet induces stimulation of renal 2-OGDH complex probably at post-transcriptional level.

The article addresses the issue of the development of the metropolitan functions of the city of Bialystok, which does not meet all the criteria necessary to qualify as a metropolitan center. According to the National Spatial Development Concept 2030 (NSDC), Bialystok was classified as a regional city of national importance, i.e. a site of systematic con-centration of metropolitan functions of national and international importance. The classification also suggests that the city has a chance to increase its importance and role in the national settlement network. An analysis of some of the city’s functions has shown a strengthening of some of the metropolitan functions and their specializations. These changes are facilitated by the spatial policy adopted in the NSDC.

Bacteriophytochromes (Bphs) are red-light photoreceptors found in photosynthetic and non-photosynthetic bacteria that have been engineered into infrared fluorescent protein markers. Bphs are composed of a photosensory module that is covalently linked to an effector/regulatory module, usually a histidine kinase (HK) domain. Light-induced, global structural changes are proposed to originate within the covalently attached biliverdin chromophore, a linear tetrapyrrole, and propagate through the protein. Bphs undergo reversible photoconversion between two distinct red and far-red light absorbing states, denoted Pr and Pfr respectively. For most Bphs, Pr is the dark-adapted state. The energy dissipated during Pr/Pfr photoconversion is proposed to directly impact the infrared fluorescence quantum yield. At this time, only structures of three different Bphs have been published, all of truncated proteins in their respective dark-adapted states. We have utilized scanning probe microscopy (SPM) to investigate the structure of intact Bphs in the light-adapted state in order to gain new insight into the mechanism of photoconversion and fluorescence. Scanning tunneling microscopy (STM) analysis of a pair of Bphs from photosynthetic bacterium R. palustris, RpBphP2 (P2) and RpBphP3 (P3) in their light-adapted states is presented in these proceedings. The concentration of the depositing protein has a key role in the molecular arrangements observed on the highly-ordered pyrolytic graphite (HOPG) surface. For example, at a high protein concentration, a hexagonal lattice of Bphs is observed by STM on a HOPG surface. Upon dilution, the photoreceptors self-organize into fiber-like structures on the surface. In these fibers, the dimer interface and the individual domains of the Bphs can be assigned and directly compared to a structural model of the intact, full-length proteins. In summary, SPM has potential to be an effective method for gaining new insight into Bph structure and dynamics.