Nelly Sapojnikova - Academia.edu (original) (raw)
Papers by Nelly Sapojnikova
Journal of Inorganic Biochemistry, Jul 1, 1998
The energetics of Cu (II) ion binding to mononucleosomes from C3HA mice liver and ascitic hepatom... more The energetics of Cu (II) ion binding to mononucleosomes from C3HA mice liver and ascitic hepatoma 22A cells was determined from their binding isotherms by equilibrium dialysis and pulse high frequency inductively coupled plasma atomic emission spectroscopy. Anticooperative binding of copper ions with normal and tumor mononucleosomes were observed under various NaCl concentrations (0.002; 0.02; 0.2 M). The binding constants of Cu(II) ion with normal mononucleosomes in 0.002, 0.02, 0.2 M NaCl are 6.10 x 10(4), 5.22 x 10(4), 4.31 x 10(4) respectively. The binding constants of Cu(II) ion with tumor mononucleosomes in 0.002, 0.02, 0.2 M NaCl are 6.68 x 10(4), 6.12 x 10(4), 4.82 x 10(4) respectively.
Biomedical Chromatography, 2000
The biochemist, Jan 19, 2023
Environmental Sciences
Polyhydroxyalkanoates (PHAs) are biopolymers produced by numerous bacteria and can be used in the... more Polyhydroxyalkanoates (PHAs) are biopolymers produced by numerous bacteria and can be used in the production of bioplastics. PHAs are synthesized by microorganisms by fermentation of carbon sources. Due to the different monomer structures of PHAs, there are many kinds of PHAs, and their corresponding material properties are also very different. Thus, the search for bacteria producing the PHAs is of great interest. In this study, the bacteria isolated from the environment were analyzed for the presence of PHA. PHA production was tested with staining methods Sudan Black B, Nile Blue, and Nile Red. The presence of a PHA synthase gene (phaC) was confirmed by PCR amplification. PHAs were extracted from the strains and characterized by the FTIR spectroscopy method. A biochip for a fast screening of environmental samples for the presence of PHA-producing bacteria was designed. The biochip contained 11 probes for coding class 1, 2, and 3 PHA synthase genes.
Toxics
The dose-dependent effects of single metals (Zn, Ni, and Cu) and their combinations at steady tim... more The dose-dependent effects of single metals (Zn, Ni, and Cu) and their combinations at steady time-actions on the cell viability of the bacteria Shewanella xiamenensis DCB 2-1, isolated from a radionuclide-contaminated area, have been estimated. The accumulation of metals by Shewanella xiamenensis DCB 2-1 in single and multi-metal systems was assessed using the inductively coupled plasma atomic emission spectroscopy. To estimate the response of the bacteria’s antioxidant defense system, doses of 20 and 50 mg/L of single studied metals and 20 mg/L of each metal in their combinations (non-toxic doses, determined by the colony-forming viability assay) were used. Emphasis was given to catalase and superoxide dismutase since they form the primary line of defense against heavy metal action and their regulatory circuit of activity is crucial. The effect of metal ions on total thiol content, an indicator of cellular redox homeostasis, in bacterial cells was evaluated. Genome sequencing of S...
Biosensors, 2021
Allergenicity assessment of transgenic plants and foods is important for food safety, labeling re... more Allergenicity assessment of transgenic plants and foods is important for food safety, labeling regulations, and health protection. The aim of this study was to develop an effective multi-allergen diagnostic approach for transgenic soybean assessment. For this purpose, multiplex polymerase chain reaction (PCR) coupled with DNA chip technology was employed. The study was focused on the herbicide-resistant Roundup Ready soya (RRS) using a set of certified reference materials consisting of 0, 0.1%, 0.5%, and 10% RRS. Technically, the procedure included design of PCR primers and probes; genomic DNA extraction; development of uniplex and multiplex PCR systems; DNA analysis by agarose gel electrophoresis; microarray development, hybridization, and scanning. The use of the asymmetric multiplex PCR method is shown to be very efficient for DNA hybridization with biochip probes. We demonstrate that newly developed fourplex PCR methods coupled with DNA-biochips enable simultaneous identificatio...
The study is devoted to a very urgent and acute problem for Georgia – remediation/restoration of ... more The study is devoted to a very urgent and acute problem for Georgia – remediation/restoration of the arsenic (As) mining and storage sites. The approach of a given work is based on using capabilities of nature itself, which has a great adaptive potential to chemical environmental pollution. The aim of the study is to identify the bacterial strains from the endemic soil microbiota, characteristic to a specific localization of arsenic contaminated sites and able to resist to the toxicant. To determine the level of arsenic contamination, soil samples have been analyzed using Inductively Coupled Plasma - Optical Emission Spectrometry method. The distribution of arsenic in soil samples splits them into categories according to the degree of contamination, ranging from 50 ppm to 13000 ppm. The local bacteria community has been studied using conventional cultivation method along with modern method of bioindication – a biochip. The low density biochip contains the relevant probes for the ide...
Water, Air, & Soil Pollution, 2021
Soil contamination with heavy metals causes heavy environmental problems, in particular toxic eff... more Soil contamination with heavy metals causes heavy environmental problems, in particular toxic effects on plants as well as on animals and humans. This article analyzes the effects of copper, a potentially toxic metal and abundant contaminant, on soil bacteria. Gram-positive soil bacteria of the Bacillus and Arthrobacter species, isolated from heavy metal contaminated areas, have been investigated as regards copper resistance. Both the studied Bacillus species (Bacillus cereus and Bacillus pumilus) are tolerant to copper, especially Bacillus cereus, but the investigated Arthrobacter oxydans species is not tolerant to copper. The oxidative stress response is important for adaptation to copper. This study focuses on the bacterial capacity to survive and in vitro antioxidant defense mechanisms for the estimation of their influence on soil restoration processes in vivo.
Water, Air, & Soil Pollution, 2020
The ecosystems near arsenic mining industrial areas are characterized with an elevated level of p... more The ecosystems near arsenic mining industrial areas are characterized with an elevated level of pollutants. In Caucasus region, such a hotspot is presented in Western Georgia: Uravi and Tsana abandoned arsenic production facilities and nearby mining tailings stored in deteriorating conditions that pose a threat to the population. The research presents a study of the local bacteria community of highly arsenic-contaminated soils (from 400 mg/kg at Uravi arsenic sulfide mineral processing facility to 11.3 g/kg at arsenic oxide storage area in Tsana) using an innovative, multitasking microscale bioanalytical method for environmental enquiries – DNA biochip (microarray). The detected Shewanella spp., Bacillus spp., and sulfate-reducing bacteria were considered as promising objects for future projects on in situ recovery of vast arsenic-contaminated areas applying remediation methods.
Water, Air, & Soil Pollution, 2018
Bacteria are regarded as the most effective in the detoxification of heavy metals, being environm... more Bacteria are regarded as the most effective in the detoxification of heavy metals, being environmental compatible. Metalloresistant bacteria are usually found in nature in highly contaminated environment where they interact with a combination of several toxic metals. For the present research, Arthrobacter oxydans and Arthrobacter globiformis have been isolated from the soil samples of the most polluted regions of Georgia, rich with manganese and iron, and contain co-produced toxic metals such as Cr, V, Zn, Ni, Pb, and Mo. We have studied the effects of the metals with different valence/charge on the metalloresistant Arthrobacter spp., the divalent cation—Zn(II) and the hexavalent anion—Cr(VI). The permanent presence of a nontoxic concentration of zinc alone or zinc together with the subtoxic concentration of chromium at the growth of A. oxydans and A. globiformis as batch culture causes the activation of the zinc primary uptake system transporters from the ZIP family (Zrt1). Chromium does not affect the process. The studied Arthrobacter spp. differ by the character of the activation of the antioxidant defense system. Chromium and zinc concomitant action causes the strongest oxidative stress in the case of A. globiformis that is demonstrated by the increased activity of superoxide dismutase (SOD) and catalase. In the case of A. oxydans, the zinc separate action, and the joint action of zinc and chromium decreases the activity of SOD and catalase. The antioxidant system is active in A. globiformis at the prolonged action of metals (96 h), whereas the cells of A. oxyidans activate the other defense mechanisms to survive.
Journal of biotechnology, Jan 20, 2017
The efficiency of hybridization signal detection in a biochip is affected by the method used for ... more The efficiency of hybridization signal detection in a biochip is affected by the method used for test DNA preparation, such as fragmentation, amplification and fluorescent labelling. DNA fragmentation is the commonest methods used and it is recognised as a critical step in biochip analysis. Currently methods used for DNA fragmentation are based either on sonication or on the enzymatic digestion. In this study, we compared the effect of different types of enzymatic DNA fragmentations, using DNase I to generate ssDNA breaks, NEBNext dsDNA fragmentase and SaqAI restrictase, on DNA labelling. DNA from different Desulfovibrio species was used as a substrate for these enzymes. Of the methods used, DNA fragmented by NEBNext dsDNA Fragmentase digestion was subsequently labelled with the greatest efficiency. As a result of this, the use of this enzyme to fragment target DNA increases the sensitivity of biochip-based detection significantly, and this is an important consideration when determi...
Biomedical Chromatography, 2000
The Scientific World JOURNAL, 2004
In the present study, the antioxidant capacity against hydrogen peroxide (H2O2), one of the stres... more In the present study, the antioxidant capacity against hydrogen peroxide (H2O2), one of the stress-inducing agents, was investigated in two distinct cell lines: L-41 (human epithelial-like cells) and HLF (human diploid lung fibroblasts), which differ in tissue origin, life span in culture, proliferate activity, and special enzyme system activity. The cell antioxidant capacity against H2O2was estimated by the electron spin resonance (ESR) spin-trapping technique in the Fenton reaction system via Fe+2ion action with H2O2resulting in hydroxyl radical generation. The effects of catalase inhibitors, such as sodium azide and 3-amino-1,2,4-triazole, on the antioxidant capacity of cells were tested. Based on our observation, it can be concluded that the defensive capacity of cells against H2O2depends on the ratio between catalase/GPx/SOD and H2O2, especially at high-stress situations, and the intracellular balance of these enzymes are more important than the influence of the single component.
Water, Air, & Soil Pollution
Journal of Biological Chemistry, 1998
The binding of all known linker histones, named H1a through H1e, including H1 0 and H1t, to a mod... more The binding of all known linker histones, named H1a through H1e, including H1 0 and H1t, to a model chromatin complex based on a DNA fragment containing the mouse mammary tumor virus long terminal repeat promotor was systematically studied. As for the histone subtype H1b, we found a dissociation constant of 8 -16 nM to a single mononucleosome (210 base pairs), whereas the binding constant of all other subtypes varied between 2 and 4 nM. Most of the H1 histones, namely H1a, H1c, H1d/e, and H1 0 , completely aggregate polynucleosomes (1.3 kilobase pairs, 6 nucleosomes) at 270 -360 nM, corresponding to a molar ratio of six to eight H1 molecules per reconstituted nucleosome. To form aggregates with the histones H1t and H1b, however, greater amounts of protein were required. Furthermore, our results show that specific types of in vivo phosphorylation of the linker histone tails influence both the binding to mononucleosomes and the aggregation of polynucleosomes. S phase-specific phosphorylation with one to three phosphate groups at specific sites in the C terminus influences neither the binding to a mononucleosome nor the aggregation of polynucleosomes. In contrast, highly phosphorylated H1 histones with four to five phosphate groups in the C and N termini reveal a very high binding affinity to a mononucleosome but a low chromatin aggregation capability. These findings suggest that specific S phase or mitotic phosphorylation sites act independently and have distinct functional roles.
Thescientificworldjournal, 2004
In the present study, the antioxidant capacity against hydrogen peroxide (H 2 O 2 ), one of the s... more In the present study, the antioxidant capacity against hydrogen peroxide (H 2 O 2 ), one of the stress-inducing agents, was investigated in two distinct cell lines: L-41 (human epithelial-like cells) and HLF (human diploid lung fibroblasts), which differ in tissue origin, life span in culture, proliferate activity, and special enzyme system activity. The cell antioxidant capacity against H 2 O 2 was estimated by the electron spin resonance (ESR) spin-trapping technique in the Fenton reaction system via Fe +2 ion action with H 2 O 2 resulting in hydroxyl radical generation. The effects of catalase inhibitors, such as sodium azide and 3-amino-1,2,4-triazole, on the antioxidant capacity of cells were tested. Based on our observation, it can be concluded that the defensive capacity of cells against H 2 O 2 depends on the ratio between catalase/GPx/SOD and H 2 O 2 , especially at high-stress situations, and the intracellular balance of these enzymes are more important than the influence of the single component.
Fresenius of …, 2002
It was investigated both the changes of total cell protein composition and the composition of cel... more It was investigated both the changes of total cell protein composition and the composition of cell wall protein of A.oxydans under Cr(VI) action. The effect of concentration of chromium on the protein composition of cells grown in the culture medium was studied by adding Cr(VI) (as potassium chromate ) at the beginning of the stationary phase of growth. The range of concentrations studied was from 3.5 ppm to 210 ppm. The effect of Cr(VI) exposure time was investigated by adding 35 ppm Cr(VI) in the culture medium. The time -course of chromium action considered was from 1 hr to 72 hrs (without subculture). The protein concentrations were measured with Roche Protein Assay ESL kit. The protein compositions of the whole cell extract and the cell wall were characterized by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) on 10% (w/w) acrylamide g el. The cell wall protein was investigated by capillary electrophoresis too. It was observed that the protein composition of the bacterial extract begins to change at 28 ppm chromium in the culture medium. Similar changes were observed in the whole protein extract composition after a 40 -hour exposure to chromate at 35 ppm. In all cases, the relative quantity of proteins of different molecular weight changed. Those that are mostly affected are the protein with a molecular weight about 80 kDa, the protein fraction with molecular weight about 45 kDa and the cell wall protein with a molecular weight 60 kDa. According to results obtained, the main part of chromium is transformed on the cell wall. Such a suggestion was confirmed by Electron Spin Resonance (ESR) and microcalorimetry measurements.
Journal of Inorganic Biochemistry, 1997
... 6. B. Mazus, KH Falchuk, and BL Vallee, Biochemistry 23, 42 (1984). 7. EL Andronikashvili and... more ... 6. B. Mazus, KH Falchuk, and BL Vallee, Biochemistry 23, 42 (1984). 7. EL Andronikashvili and LM Mosulishvili, in Metals Ions in Biological Systems, H. Sigel and A. Sigel, Eds., Marcel Dekker, New York, Basel, 1980, Vol. 10, Chap. ... 18. CKR Makar and PR Williams, J. Inorg. ...
Journal of Inorganic Biochemistry, Jul 1, 1998
The energetics of Cu (II) ion binding to mononucleosomes from C3HA mice liver and ascitic hepatom... more The energetics of Cu (II) ion binding to mononucleosomes from C3HA mice liver and ascitic hepatoma 22A cells was determined from their binding isotherms by equilibrium dialysis and pulse high frequency inductively coupled plasma atomic emission spectroscopy. Anticooperative binding of copper ions with normal and tumor mononucleosomes were observed under various NaCl concentrations (0.002; 0.02; 0.2 M). The binding constants of Cu(II) ion with normal mononucleosomes in 0.002, 0.02, 0.2 M NaCl are 6.10 x 10(4), 5.22 x 10(4), 4.31 x 10(4) respectively. The binding constants of Cu(II) ion with tumor mononucleosomes in 0.002, 0.02, 0.2 M NaCl are 6.68 x 10(4), 6.12 x 10(4), 4.82 x 10(4) respectively.
Biomedical Chromatography, 2000
The biochemist, Jan 19, 2023
Environmental Sciences
Polyhydroxyalkanoates (PHAs) are biopolymers produced by numerous bacteria and can be used in the... more Polyhydroxyalkanoates (PHAs) are biopolymers produced by numerous bacteria and can be used in the production of bioplastics. PHAs are synthesized by microorganisms by fermentation of carbon sources. Due to the different monomer structures of PHAs, there are many kinds of PHAs, and their corresponding material properties are also very different. Thus, the search for bacteria producing the PHAs is of great interest. In this study, the bacteria isolated from the environment were analyzed for the presence of PHA. PHA production was tested with staining methods Sudan Black B, Nile Blue, and Nile Red. The presence of a PHA synthase gene (phaC) was confirmed by PCR amplification. PHAs were extracted from the strains and characterized by the FTIR spectroscopy method. A biochip for a fast screening of environmental samples for the presence of PHA-producing bacteria was designed. The biochip contained 11 probes for coding class 1, 2, and 3 PHA synthase genes.
Toxics
The dose-dependent effects of single metals (Zn, Ni, and Cu) and their combinations at steady tim... more The dose-dependent effects of single metals (Zn, Ni, and Cu) and their combinations at steady time-actions on the cell viability of the bacteria Shewanella xiamenensis DCB 2-1, isolated from a radionuclide-contaminated area, have been estimated. The accumulation of metals by Shewanella xiamenensis DCB 2-1 in single and multi-metal systems was assessed using the inductively coupled plasma atomic emission spectroscopy. To estimate the response of the bacteria’s antioxidant defense system, doses of 20 and 50 mg/L of single studied metals and 20 mg/L of each metal in their combinations (non-toxic doses, determined by the colony-forming viability assay) were used. Emphasis was given to catalase and superoxide dismutase since they form the primary line of defense against heavy metal action and their regulatory circuit of activity is crucial. The effect of metal ions on total thiol content, an indicator of cellular redox homeostasis, in bacterial cells was evaluated. Genome sequencing of S...
Biosensors, 2021
Allergenicity assessment of transgenic plants and foods is important for food safety, labeling re... more Allergenicity assessment of transgenic plants and foods is important for food safety, labeling regulations, and health protection. The aim of this study was to develop an effective multi-allergen diagnostic approach for transgenic soybean assessment. For this purpose, multiplex polymerase chain reaction (PCR) coupled with DNA chip technology was employed. The study was focused on the herbicide-resistant Roundup Ready soya (RRS) using a set of certified reference materials consisting of 0, 0.1%, 0.5%, and 10% RRS. Technically, the procedure included design of PCR primers and probes; genomic DNA extraction; development of uniplex and multiplex PCR systems; DNA analysis by agarose gel electrophoresis; microarray development, hybridization, and scanning. The use of the asymmetric multiplex PCR method is shown to be very efficient for DNA hybridization with biochip probes. We demonstrate that newly developed fourplex PCR methods coupled with DNA-biochips enable simultaneous identificatio...
The study is devoted to a very urgent and acute problem for Georgia – remediation/restoration of ... more The study is devoted to a very urgent and acute problem for Georgia – remediation/restoration of the arsenic (As) mining and storage sites. The approach of a given work is based on using capabilities of nature itself, which has a great adaptive potential to chemical environmental pollution. The aim of the study is to identify the bacterial strains from the endemic soil microbiota, characteristic to a specific localization of arsenic contaminated sites and able to resist to the toxicant. To determine the level of arsenic contamination, soil samples have been analyzed using Inductively Coupled Plasma - Optical Emission Spectrometry method. The distribution of arsenic in soil samples splits them into categories according to the degree of contamination, ranging from 50 ppm to 13000 ppm. The local bacteria community has been studied using conventional cultivation method along with modern method of bioindication – a biochip. The low density biochip contains the relevant probes for the ide...
Water, Air, & Soil Pollution, 2021
Soil contamination with heavy metals causes heavy environmental problems, in particular toxic eff... more Soil contamination with heavy metals causes heavy environmental problems, in particular toxic effects on plants as well as on animals and humans. This article analyzes the effects of copper, a potentially toxic metal and abundant contaminant, on soil bacteria. Gram-positive soil bacteria of the Bacillus and Arthrobacter species, isolated from heavy metal contaminated areas, have been investigated as regards copper resistance. Both the studied Bacillus species (Bacillus cereus and Bacillus pumilus) are tolerant to copper, especially Bacillus cereus, but the investigated Arthrobacter oxydans species is not tolerant to copper. The oxidative stress response is important for adaptation to copper. This study focuses on the bacterial capacity to survive and in vitro antioxidant defense mechanisms for the estimation of their influence on soil restoration processes in vivo.
Water, Air, & Soil Pollution, 2020
The ecosystems near arsenic mining industrial areas are characterized with an elevated level of p... more The ecosystems near arsenic mining industrial areas are characterized with an elevated level of pollutants. In Caucasus region, such a hotspot is presented in Western Georgia: Uravi and Tsana abandoned arsenic production facilities and nearby mining tailings stored in deteriorating conditions that pose a threat to the population. The research presents a study of the local bacteria community of highly arsenic-contaminated soils (from 400 mg/kg at Uravi arsenic sulfide mineral processing facility to 11.3 g/kg at arsenic oxide storage area in Tsana) using an innovative, multitasking microscale bioanalytical method for environmental enquiries – DNA biochip (microarray). The detected Shewanella spp., Bacillus spp., and sulfate-reducing bacteria were considered as promising objects for future projects on in situ recovery of vast arsenic-contaminated areas applying remediation methods.
Water, Air, & Soil Pollution, 2018
Bacteria are regarded as the most effective in the detoxification of heavy metals, being environm... more Bacteria are regarded as the most effective in the detoxification of heavy metals, being environmental compatible. Metalloresistant bacteria are usually found in nature in highly contaminated environment where they interact with a combination of several toxic metals. For the present research, Arthrobacter oxydans and Arthrobacter globiformis have been isolated from the soil samples of the most polluted regions of Georgia, rich with manganese and iron, and contain co-produced toxic metals such as Cr, V, Zn, Ni, Pb, and Mo. We have studied the effects of the metals with different valence/charge on the metalloresistant Arthrobacter spp., the divalent cation—Zn(II) and the hexavalent anion—Cr(VI). The permanent presence of a nontoxic concentration of zinc alone or zinc together with the subtoxic concentration of chromium at the growth of A. oxydans and A. globiformis as batch culture causes the activation of the zinc primary uptake system transporters from the ZIP family (Zrt1). Chromium does not affect the process. The studied Arthrobacter spp. differ by the character of the activation of the antioxidant defense system. Chromium and zinc concomitant action causes the strongest oxidative stress in the case of A. globiformis that is demonstrated by the increased activity of superoxide dismutase (SOD) and catalase. In the case of A. oxydans, the zinc separate action, and the joint action of zinc and chromium decreases the activity of SOD and catalase. The antioxidant system is active in A. globiformis at the prolonged action of metals (96 h), whereas the cells of A. oxyidans activate the other defense mechanisms to survive.
Journal of biotechnology, Jan 20, 2017
The efficiency of hybridization signal detection in a biochip is affected by the method used for ... more The efficiency of hybridization signal detection in a biochip is affected by the method used for test DNA preparation, such as fragmentation, amplification and fluorescent labelling. DNA fragmentation is the commonest methods used and it is recognised as a critical step in biochip analysis. Currently methods used for DNA fragmentation are based either on sonication or on the enzymatic digestion. In this study, we compared the effect of different types of enzymatic DNA fragmentations, using DNase I to generate ssDNA breaks, NEBNext dsDNA fragmentase and SaqAI restrictase, on DNA labelling. DNA from different Desulfovibrio species was used as a substrate for these enzymes. Of the methods used, DNA fragmented by NEBNext dsDNA Fragmentase digestion was subsequently labelled with the greatest efficiency. As a result of this, the use of this enzyme to fragment target DNA increases the sensitivity of biochip-based detection significantly, and this is an important consideration when determi...
Biomedical Chromatography, 2000
The Scientific World JOURNAL, 2004
In the present study, the antioxidant capacity against hydrogen peroxide (H2O2), one of the stres... more In the present study, the antioxidant capacity against hydrogen peroxide (H2O2), one of the stress-inducing agents, was investigated in two distinct cell lines: L-41 (human epithelial-like cells) and HLF (human diploid lung fibroblasts), which differ in tissue origin, life span in culture, proliferate activity, and special enzyme system activity. The cell antioxidant capacity against H2O2was estimated by the electron spin resonance (ESR) spin-trapping technique in the Fenton reaction system via Fe+2ion action with H2O2resulting in hydroxyl radical generation. The effects of catalase inhibitors, such as sodium azide and 3-amino-1,2,4-triazole, on the antioxidant capacity of cells were tested. Based on our observation, it can be concluded that the defensive capacity of cells against H2O2depends on the ratio between catalase/GPx/SOD and H2O2, especially at high-stress situations, and the intracellular balance of these enzymes are more important than the influence of the single component.
Water, Air, & Soil Pollution
Journal of Biological Chemistry, 1998
The binding of all known linker histones, named H1a through H1e, including H1 0 and H1t, to a mod... more The binding of all known linker histones, named H1a through H1e, including H1 0 and H1t, to a model chromatin complex based on a DNA fragment containing the mouse mammary tumor virus long terminal repeat promotor was systematically studied. As for the histone subtype H1b, we found a dissociation constant of 8 -16 nM to a single mononucleosome (210 base pairs), whereas the binding constant of all other subtypes varied between 2 and 4 nM. Most of the H1 histones, namely H1a, H1c, H1d/e, and H1 0 , completely aggregate polynucleosomes (1.3 kilobase pairs, 6 nucleosomes) at 270 -360 nM, corresponding to a molar ratio of six to eight H1 molecules per reconstituted nucleosome. To form aggregates with the histones H1t and H1b, however, greater amounts of protein were required. Furthermore, our results show that specific types of in vivo phosphorylation of the linker histone tails influence both the binding to mononucleosomes and the aggregation of polynucleosomes. S phase-specific phosphorylation with one to three phosphate groups at specific sites in the C terminus influences neither the binding to a mononucleosome nor the aggregation of polynucleosomes. In contrast, highly phosphorylated H1 histones with four to five phosphate groups in the C and N termini reveal a very high binding affinity to a mononucleosome but a low chromatin aggregation capability. These findings suggest that specific S phase or mitotic phosphorylation sites act independently and have distinct functional roles.
Thescientificworldjournal, 2004
In the present study, the antioxidant capacity against hydrogen peroxide (H 2 O 2 ), one of the s... more In the present study, the antioxidant capacity against hydrogen peroxide (H 2 O 2 ), one of the stress-inducing agents, was investigated in two distinct cell lines: L-41 (human epithelial-like cells) and HLF (human diploid lung fibroblasts), which differ in tissue origin, life span in culture, proliferate activity, and special enzyme system activity. The cell antioxidant capacity against H 2 O 2 was estimated by the electron spin resonance (ESR) spin-trapping technique in the Fenton reaction system via Fe +2 ion action with H 2 O 2 resulting in hydroxyl radical generation. The effects of catalase inhibitors, such as sodium azide and 3-amino-1,2,4-triazole, on the antioxidant capacity of cells were tested. Based on our observation, it can be concluded that the defensive capacity of cells against H 2 O 2 depends on the ratio between catalase/GPx/SOD and H 2 O 2 , especially at high-stress situations, and the intracellular balance of these enzymes are more important than the influence of the single component.
Fresenius of …, 2002
It was investigated both the changes of total cell protein composition and the composition of cel... more It was investigated both the changes of total cell protein composition and the composition of cell wall protein of A.oxydans under Cr(VI) action. The effect of concentration of chromium on the protein composition of cells grown in the culture medium was studied by adding Cr(VI) (as potassium chromate ) at the beginning of the stationary phase of growth. The range of concentrations studied was from 3.5 ppm to 210 ppm. The effect of Cr(VI) exposure time was investigated by adding 35 ppm Cr(VI) in the culture medium. The time -course of chromium action considered was from 1 hr to 72 hrs (without subculture). The protein concentrations were measured with Roche Protein Assay ESL kit. The protein compositions of the whole cell extract and the cell wall were characterized by sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE) on 10% (w/w) acrylamide g el. The cell wall protein was investigated by capillary electrophoresis too. It was observed that the protein composition of the bacterial extract begins to change at 28 ppm chromium in the culture medium. Similar changes were observed in the whole protein extract composition after a 40 -hour exposure to chromate at 35 ppm. In all cases, the relative quantity of proteins of different molecular weight changed. Those that are mostly affected are the protein with a molecular weight about 80 kDa, the protein fraction with molecular weight about 45 kDa and the cell wall protein with a molecular weight 60 kDa. According to results obtained, the main part of chromium is transformed on the cell wall. Such a suggestion was confirmed by Electron Spin Resonance (ESR) and microcalorimetry measurements.
Journal of Inorganic Biochemistry, 1997
... 6. B. Mazus, KH Falchuk, and BL Vallee, Biochemistry 23, 42 (1984). 7. EL Andronikashvili and... more ... 6. B. Mazus, KH Falchuk, and BL Vallee, Biochemistry 23, 42 (1984). 7. EL Andronikashvili and LM Mosulishvili, in Metals Ions in Biological Systems, H. Sigel and A. Sigel, Eds., Marcel Dekker, New York, Basel, 1980, Vol. 10, Chap. ... 18. CKR Makar and PR Williams, J. Inorg. ...