Institute of Cryobiology and Food Technology

Sofia, Bulgaria

Institute of Cryobiology and Food Technology

Sofia, Bulgaria
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Mladenova R.B.,Bulgarian Academy of Science | Firzov C.,Institute of Cryobiology and Food Technology | Yordanov N.D.,Bulgarian Academy of Science
Radiation Physics and Chemistry | Year: 2010

Nutritive supplements Enoviton, Enoviton C and Enoviton CE containing standardized anthocyanins from lyophilized red wine, vitamins (some of them) and excipients were investigated by EPR spectrometry before and after gamma-irradiation. Non-irradiated samples exhibit one singlet line with g=2.0039±0.0002, most probably due to free radicals from anthocyanins. After irradiation with 10. kGy gamma-rays, tablets of Enoviton, Enoviton C and Enoviton CE, all exhibit complex EPR signals centered at a g-value of g=2.0034. The EPR spectrum of irradiated Enoviton is different from that of Enoviton C or Enoviton CE due to the overlap of the spectra of microcrystalline cellulose and the background singlet spectrum present in all tablets with the EPR resonance due to irradiated ascorbic acid (in Enoviton C and Enoviton CE). Gamma-induced free radicals exhibit long time stability-for a six months period the intensity of central peak decrease with 30-40%. © 2010 Elsevier Ltd.


Doneva M.,Institute of Cryobiology and Food Technology | Nacheva I.,Institute of Cryobiology and Food Technology | Metodieva P.,Institute of Cryobiology and Food Technology | Todorov Y.,Institute of Information and Communication Technologies | And 3 more authors.
Bulgarian Journal of Agricultural Science | Year: 2014

Good nutrition is key factor for human health. Conditions of secondary insufficiency of the gastric gland and a decreased production of digestive enzymes lead to changes in the gastric-intestinal metabolism, which imposes the intake polyenzyme products as food supplement. The created on the basis of freeze-drying complex polyenzyme product with its composition, containing the main groups digestive enzymes (chymosin, α – amylase, bromelain, lipase), incorporated in a hydrocolloid matrix and in combination with plant biologically active components is appropriate for prophylaxis in cases of gastric-intestinal tract discomfort and disturbed digestion. The obtained product was qualified by organoleptic, biochemical, physical-chemical and microbiological characteristics. The retaining of the catalytic activity of the enzyme substances and the chemical composition of the incorporated biologically active substances has been established. © 2014, National Centre for Agrarian Sciences. All rights reserved.


Stoycheva T.,Institute of Cryobiology and Food Technology | Pesheva M.,Sofia University | Venkov P.,Institute of Cryobiology and Food Technology
Yeast | Year: 2010

Here we provide evidence for a dependence between the increased production of reactive oxygen species and the activation of Ty1 retrotransposition. We have found that the strong activator of Ty1 mobility, methylmethane sulphonate, can not induce Ty1 retrotransposition in cells with compromised mitochondrial oxidative phosphorylation (rho-; sco1Δ), which is the major source for production of reactive oxygen species (ROS) in Saccharomyces cerevisiae. The quantitative estimation of superoxide anions in living cells showed that rho+ cells exposed to methylmethane sulphonate increase Ty1 retrotransposition and superoxide levels. The increase of superoxide anions by the superoxide generator menadione is accompanied by induction of Ty1 mobility without any treatment with a DNA-damaging agent. Higher frequencies of retrotransposition were found in rho+ and rho-cells treated with exogenously added hydrogen peroxide or in cells with disrupted YAP1 gene characterized by increased intracellular levels of hydrogen peroxide. These data indicate that increased levels of ROS may have an independent and key role in the induction of Ty1 retrotransposition. Copyright © 2010 John Wiley & Sons, Ltd.


Todorova T.,Sofia University | Pesheva M.,Sofia University | Stamenova R.,Institute of Cryobiology and Food Technology | Dimitrov M.,Sofia University | Venkov P.,Institute of Cryobiology and Food Technology
Yeast | Year: 2012

Although fragmentation of DNA has been observed in cells undergoing freezing procedures, a mutagenic effect of sub-zero temperature treatment has not been proved by induction and isolation of mutants in nuclear DNA (nDNA). In this communication we supply evidence for mutagenicity of freezing on nDNA of Saccharomyces cerevisiae cells. In the absence of cryoprotectors, cooling for 2 h at +4°C and freezing for 1 h at -10°C and 16 h at -20°C, with a cooling rate of 3°C/min, resulted in induction of frame-shift and reverse mutations in microsatellite and coding regions of nDNA. The sub-zero temperature exposure also has a strong recombinogenic effect, evidenced by induction of gene-conversion and crossing-over events. Freezing induces mutations and enhances recombination with a frequency equal to or higher than that of methylmethanesulphonate at comparable survival rates. The signals for the appearance of nDNA lesions induced by freezing are detected and transduced by the DNA damage pathway. Extracellular cryoprotectors did not prevent the mutagenic effect of freezing, while accumulation of trehalose inside cells reduced nDNA cryodamage. Freezing of cells is accompanied by generation of high ROS levels, and the oxidative stress raised during the freeze-thaw process is the most likely reason for the DNA damaging effect. Experiments with mitochondrial rho - mutants or scavengers of ROS indicated that mutagenic and recombinogenic effects of sub-zero temperatures can be decreased but not eliminated by reduction of ROS level. The complete protection against cryodamage in nDNA required simultaneous usage of intracellular cryoprotector and ROS scavenger during the freeze-thaw process. © 2012 John Wiley & Sons, Ltd.


Daskalova N.,Institute of Cryobiology and Food Technology
Journal of the University of Chemical Technology and Metallurgy | Year: 2011

The lichenase and laminarinase are/3-glucanases. They take part in the degradation of/3-glucans, which are present in cereals- wheat, barley, oats, rye. Both enzymes find application in the production of wine and beer, in the food industry and also as a feed component in animal food. The conservation of lichenase and laminarinase by lyophilization of liquid culture, produced from Trichoderma sp. 405 Strain M7 was investigated. This strain was bought from the National bank for industrial microorganisms and cell cultures- NBIMCC. The lyophilization was done in a freeze-drying installation HOCHVAKUUM" TG-16. The lichenase and laminarinase activities of the liquid culture were determined during cultivation of Trichoderma sp. 405 Strain M7 and one month after its lyophilization. It was established that both enzyme activities remain high after the process of conservation.


Daskalova N.,Institute of Cryobiology and Food Technology
Journal of the University of Chemical Technology and Metallurgy | Year: 2012

Trichoderma sp. 405 Strain M7 produces laminarinase and lichenase, which pertain to the β-glucanases. The conservation of the liquid culture, containing both enzymes in a fridge (4-8°C) immediately after the cultivation was investigated. Both enzyme activities were determined after freezing of the liquid culture at -20/-25°C followed by unfreezing and conservation at 20°C. The laminarinase and lichenase activities were determined also by freezing of the liquid culture at -20/-25°C followed by unfreezing and preservation in a fridge (4-8oC). The conservation by lyophiliza-tion of the liquid culture, produced from Trichoderma sp. 405 Strain M7 was investigated. It was established that both enzyme activities remain highest after conservation of the liquid culture by the process of lyophilization.


Daskalova N.,Institute of Cryobiology and Food Technology | Marinova G.,Institute of Cryobiology and Food Technology
Journal of Chemical Technology and Metallurgy | Year: 2015

The β-glucanase enzymes find wide application in the brewing. It was obtained an enzyme preparation with laminarinase and lichenase activity, produced from Trichoderma sp. 405 and was investigated its application in the technological process of brewing wort preparation. It was found that the studied enzyme preparation has a hydrolytic effect on the b-glucans and the hemicelluloses of the used ingredients. From economical point of view the obtained enzyme preparation, added at a dose of 0,04 % compared to the used ingredients, leads to receiving of brewing wort, containing b-glucans suitable for healthy lifestyle.


PubMed | Institute of Cryobiology and Food Technology
Type: Journal Article | Journal: Yeast (Chichester, England) | Year: 2010

Here we provide evidence for a dependence between the increased production of reactive oxygen species and the activation of Ty1 retrotransposition. We have found that the strong activator of Ty1 mobility, methylmethane sulphonate, can not induce Ty1 retrotransposition in cells with compromised mitochondrial oxidative phosphorylation (rho(-); sco1Delta), which is the major source for production of reactive oxygen species (ROS) in Saccharomyces cerevisiae. The quantitative estimation of superoxide anions in living cells showed that rho(+) cells exposed to methylmethane sulphonate increase Ty1 retrotransposition and superoxide levels. The increase of superoxide anions by the superoxide generator menadione is accompanied by induction of Ty1 mobility without any treatment with a DNA-damaging agent. Higher frequencies of retrotransposition were found in rho(+) and rho(-) cells treated with exogenously added hydrogen peroxide or in cells with disrupted YAP1 gene characterized by increased intracellular levels of hydrogen peroxide. These data indicate that increased levels of ROS may have an independent and key role in the induction of Ty1 retrotransposition.


Dimitrov M.,Sofia University | Venkov P.,Institute of Cryobiology and Food Technology | Pesheva M.,Sofia University
Archives of Toxicology | Year: 2011

In previous laboratory and environmental studies, the Ty1 short-term test showed positive responses (i.e. induced mobility of the Ty1 retrotransposon) to carcinogenic genotoxins. Here, we provide evidence for a causal relationship between increased level of reactive oxygen species and induction the mobility of the Ty1 retrotransposon. Results obtained in concentration and time-dependent experiments after treatment, the tester cells with carcinogenic genotoxins [benzo(a)pyrene, benzo(a)anthracene, ethylmethanesulfonate, formamide], free bile acids (chenodeoxycholic, lithocholic acids) and metals (arsenic, hexavelant chromium, lead) showed a simultaneous increase in both cellular level of the superoxide anions and Ty1 retrotransposition rates. Treatment with the noncarcinogenic genotoxins [benzo(e)pyrene, benzo(b)anthracen, anthracene], conjugated bile acids (taurodeoxycholic, glycodeoxycholic acids) and metals (zinc, trivalent chromium) did not change significantly superoxide anions level and Ty1 retrotransposition rate. The induction by carcinogens of the Ty1 mobility seems to depend on the accumulation of superoxide anions, since the addition of the scavenger N-acetylcysteine resulted in loss of both increased amount of superoxide anions and induced Ty1 retrotransposition. Increased hydrogen peroxide levels are also involved in the induction of Ty1 retrotransposition rates in response to treatment with carcinogenic genotoxins, as evidenced by disruption of YAP1 gene in the tester cells. It is concluded that the carcinogen-induced high level of reactive oxygen species play a primary and key role in determination the selective response of Ty1 test to carcinogenic genotoxins. © 2010 Springer-Verlag.

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