Research of the academician I. N. Bulankin on problems of protein chemistry

The article presents an information about scientific researches on the problem of chemical properties and structure of proteins, which were carried out intensively by the biochemists of Kharkiv State University in 30-50 years of XX cent., headed by I. N. Bulankin, academician of Ukrainian Academy of Sciences. This researches dealt with the processes of proteolysis and protein denaturation, the peculiarities of globular and fibrilliar proteins behavior in solution, the properties of complexes with proteins and nucleic acids, etc. The historic analysis of origin and development of this scientific problem at the biochemistry chair of the university and its gradual replacement by researches with other biochemical problems has been carried out. The data concerned with the general situation in the field protein structure of estimation at the world and home biochemistry are cited too. In connection with the above presented the authors give the grounded conclusions about the importance of the scientific researches carried out by I. N. Bulankin as well as about.     

Garlic ameliorates hyperlipidemia in chronic aminonucleoside nephrosis

Nephrotic syndrome (NS) is characterized by proteinuria, oxidative stress and endogenous hyperlipidemia. Hyperlipidemia and oxidative stress may be involved in coronary heart disease and the progression of renal damage in these patients. Garlic has been suggested to be beneficial in various disease states. Some of the beneficial effects of garlic may be secondary to its hypolipidemic and antioxidant properties. Therefore, the effect of a 2% garlic diet on acute and chronic experimental NS induced by puromycin aminonucleoside (PAN) was studied in this work. Acute NS was induced by a single injection of PAN to rats which were sacrificed 10 days later. Chronic NS was induced by repeated injections of PAN to rats which were sacrificed 84 days after the first injection. Garlic treatment was unable to modify proteinuria in either acute or chronic NS, and hypercholesterolemia and hypertriglyceridemia in acute NS. However, garlic treatment diminished significantly total-cholesterol, LDL-cholesterol and triglycerides, but not HDL-cholesterol in chronic NS. Garlic induced no change in the percentage of sclerotic glomeruli in chronic NS and a significative decrease on the percentage of sclerotic area of these glomeruli (33 ± 3% in NS+Garlic group vs. 47 ± 4% in NS group, p = 0.0126). The enhanced in vivo renal H2O2 production and the diminished renal Cu, Zn-SOD and catalase activities in acute NS, and the decreased renal catalase activity in chronic NS were not prevented by garlic treatment. These data indicate that garlic treatment ameliorates hyperlipidemia and renal damage in chronic NS which is unrelated to proteinuria or antioxidant enzymes.     

Free heme pool and activity of key enzyme of heme synthesis in the rat liver under action of agents affecting reduced glutathione level

The decrease of GSH level in the rat liver was found to be accompanied by an increase of tryptophan 2,3-dioxygenase (TDO) heme saturation during first hours after HgCl2, phenylhydrazine (Ph) injection or rhabdomyolysis (the coefficient of correlation -0.978). The activity of the key enzyme of heme synthesis--5-aminolevulinate synthase (ALAS) was 2.5-fold increased in the first hours after Ph injection and rhabdomyolysis. Glutathione injection in vivo as well as CdCl2 caused the increase of GSH content and the inhibition of ALAS. The coefficient of correlation for GSH content and ALAS activity under the action of agents altering both these parameters (CdCl2, Ph, GSH injection and rhabdomyolysis) is 0.938. Taking into account the presence of heme regulatory motif with conserved cystein in many proteins, including ALAS and TDO (accession number in SwissProt database AAH61793 and P21643, respectively), the link between alterations of GSH content, ALAS activity and heme saturation of TDO in the rat liver could be proposed. The further experiments should be performed in order to elucidate the mechanisms of GSH level influence on free heme pool formation in the liver cells.     

Estrogen receptor alpha is required for mammary development and the induction of mammary hyperplasia and epigenetic alterations in the aromatase transgenic mice

Aromatase transgenic mice exhibit hyperplastic and dysplastic changes, attesting to the importance of local estrogen in breast carcinogenesis. These mice also show increased levels of the estrogen receptor and β (ER, ERβ) suggesting that this receptor may play an important role in the initiation of estrogen-mediated mammary hyperplasia observed in these mice. To address the specific role of ER in the mammary development and in the induction of estrogen-mediated hyperplasia in aromatase transgenic mice, we have generated MMTV-aromatase × ER knockout cross (referred as aromatase/ERKO). Even though ERβ is expressed in aromatase/ERKO mice, lack of ER leads to impaired mammary growth in these mice. The data suggest that ER plays an important role in the mammary gland development as well as in the induction of mammary hyperplasia in aromatase transgenic mice. Lack of ER expression in the aromatase/ERKO mice resulted in a decrease in the expression of Cyclin D1, PCNA and TGFβ relative to the aromatase parental strain. The studies involving aromatase/ERKO mice show that lack of ER results in impaired mammary development even in the presence of continuous tissue estrogen, suggesting estrogen/ER-mediated actions are critical for mammary development and carcinogenesis.     

Role of p38 in nitric oxide synthase and cyclooxygenase expression, and nitric oxide and PGE2 synthesis in human gingival fibroblasts stimulated with lipopolysaccharides

Periodontal disease, a gingival inflammatory disease caused by gram-negative bacteria, is the main cause of tooth loss. Lipopolysaccharides (LPS) present in bacterial cell walls induce human gingival fibroblasts' production of pro-inflammatory cytotoxins such as IL-1beta and TNFalpha. The goal of this study was to determine p38 role in the expression of inducible nitric oxide synthase enzyme (i-NOS) and cyclooxygenase (COX-2), as well as in PGE(2) and nitric oxide synthesis in human gingival fibroblasts challenged with LPS. We found that lipopolysaccharides induced a rapid and significant increase in p38 phosphorylation. After interruption of p38 transduction pathway by pre-treatment with inhibitor SB203580, no response to stimulation with LPS was observed; i-NOS expression and nitric oxide synthesis was completely blocked. However, p38 inhibition only partially blocked COX-2 expression and PGE2 synthesis. We conclude that p38 is critically involved in i-NOS induction, and that it participates in COX-2 expression and in PGE2 synthesis.     

Effect of pentoxyphylline on certain indicators of the proteinase-proteinase inhibitor system in rats upon administration of cycloheximide

The pentoxifylline influence on neutral proteinase, alpha-2-macroglobulin, trypsin-alpha-1-proteinase inhibitor and elastaseinhibitory activity under cycloheximide injection has been investigated. Two hours after cycloheximide injection the activity of neutral proteinases increases in rats serum, lungs, heart, liver and kidneys. The preliminary injection of pentoxifylline prevents increase of neutral proteinases activity. Cycloheximide also decreases alpha-2-macroglobulin activity in serum and liver and trypsin-, elastaseinhibitory activity of alpha-1-proteinase inhibitor in all investigated organs. At using pentoxifylline the alpha-2-macroglobulin activity doesn't change in liver and increases in serum in comparison with only cycloheximide and there are no observed any alpha-1 inhibitor proteinase activity changes in rats serum and organs.     

Activity of cytoplasmic NADP-dependent dehydrogenase in rat liver during induction of cytochrome P-450 by phenobarbital

Activity of oxidation enzymes of the pentosephosphate way (glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (EC 1.1.1.44), cytoplasmic malate dehydrogenase (decarboxylating oxaloacetate) (NADP+) (EC 1.1.1.40) and isocitrate dehydrogenase (NADP+) (EC 1.1.1.42) as well as the content of microsomal cytochromes b5 and P-450 in the rat liver have been studied 24 hours after 1, 2, 3, 4 and 5 intraperitoneal administrations of phenobarbital (4 mg per 100 g of the body weight). It is shown that the cytochrome P-450 content increases after a single administration of phenobarbital and then it gradually grows reaching its maximum after 4 administrations and falls after 5 administrations (though it remains high as compared to the control animals). The content of cytochrome b5 increases only after 4 administrations of phenobarbital and after 5th one it returns to the initial level. The content of microsomal gangliosides calculated per 1 mg of microsomal protein decreases after a single administration of phenobarbital and 5 days later it returns to the initial level. Activity of glucose-6-phosphate dehydrogenase increases after a single administration of phenobarbital, that of malate dehydrogenase--after 3 administrations, 6--phosphogluconate-dehydrogenase--after 4 administrations of the preparation. The 5 administrations of phenobarbital makes activity of all the mentioned dehydrogenases return to the initial level. Activity of isocitrate dehydrogenase under given conditions of the experiment does not change.     

ATP-synthetase activity, respiration and cytochromes of rat heart mitochondria in aging and hyperthyroidism

The ATP-synthetase activity, the rate of oxygen uptake under different metabolic conditions, the tightness of coupling of respiration to oxidative phosphorylation and the cytochrome contents in heart mitochondria of rats from different age groups were studied under normal conditions and in hyperthyroidism. It was found that heart mitochondria of aged animals did not practically differ in terms of their functional activity from those of the young animals. Administration of thyroxin to the animals from all age groups produced no significant effects on the state of mitochondria, increasing the rate of ATP synthesis on alpha-glycerophosphate, which was especially well-pronounced in aged animals, and the cytochrome content in 1-month-old rats.     

Vibrational spectra of an RDX film over an aluminum substrate from molecular dynamics simulations and density functional theory

We report calculated vibrational spectra in the range of 0–3,500 cm^?1 of RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) molecules adsorbed on a model aluminum surface. A molecular film was modeled using two approaches: (1) density functional theory (DFT) was used to optimize a single RDX molecule interacting with its periodic images, and (2) a group of nine molecules extracted from the crystal structure was deposited on the surface and interacted with its periodic images via molecular dynamics (MD) simulations. In both cases, the molecule was initialized in the AAA conformer geometry having the three nitro groups in axial positions, and kept that conformation in the DFT examination, but some molecules were found to change to the AAE conformer (two nitro groups in axial and one in equatorial position) in the MD analysis. The vibrational spectra obtained from both methods are similar to each other, except in the regions where collective RDX intermolecular interactions (captured by MD simulations) are important, and compare fairly well with experimental findings.