Biotechnol Biotechnol Equip
· 2014 Nov · PMID 26019588
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Biological control plays a crucial role in grapevine pathogens disease management. The cell-wall degrading enzymes chitinase, cellulase and β-glucanase have been suggested to be essential for the mycoparasitism activity...Biological control plays a crucial role in grapevine pathogens disease management. The cell-wall degrading enzymes chitinase, cellulase and β-glucanase have been suggested to be essential for the mycoparasitism activity of species against grapevine fungal pathogens. In order to develop a useful strain as a single source of these vital enzymes, it was intended to incorporate the characteristics of two parental fungicides tolerant mutants of belonging to the high chitinase producing species and the high cellulase producing species , by fusing their protoplasts. The phylogeny of the parental strains was carried out using a sequence of the 5.8S-ITS region. The BLAST of the obtained sequence identified these isolates as and . Protoplasts were isolated using lysing enzymes and were fused using polyethylene glycol. The fused protoplasts have been regenerated on protoplast regeneration minimal medium supplemented with two selective fungicides. Among the 40 fast growing fusants, 17 fusants were selected based on their enhanced growth on selective media for further studies. The fusant strains were growing 60%-70% faster than the parents up to third generation. All the 17 selected fusants exhibited morphological variations. Some fusant strains displayed threefold increased chitinase enzyme activity and twofold increase in β-glucanase enzyme activity compared to the parent strains. Most fusants showed powerful antagonistic activity against , and pathogens. Fusant number 15 showed the highest inhibition percentage (92.8%) against and while fusant number 9 showed the highest inhibition percentage (98.2%) against the growth of A hyphal intertwining and degradation phenomenon was observed by scanning electron microscope. The antagonistic effect against pathogenic fungal mycelia was due to the mycoparasitism effect of the extracellular enzymes.
Ouyang K, Li J, Huang H
… +3 more, Que Q, Li P, Chen X
Biotechnol Biotechnol Equip
· 2014 Nov · PMID 26019587
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Plant tissues contain abundant polysaccharides, phenolic compounds and other metabolites, which makes it difficult to isolate high-quality RNA from them. In addition, contains large quantities of other components, parti...Plant tissues contain abundant polysaccharides, phenolic compounds and other metabolites, which makes it difficult to isolate high-quality RNA from them. In addition, contains large quantities of other components, particularly RNA-binding alkaloids, which makes the isolation even more challenging. Here, we describe a concise and efficient RNA isolation method that combines the cetyltrimethyl ammonium bromide (CTAB) and Plant RNA Kit (Omega) protocols. Gel electrophoresis showed that RNA extracted from all tissues, using this protocol, was of good integrity and without DNA contamination. Furthermore, the isolated RNA was of high purity, with an / ratio of 2.1 and an / ratio of >2.0. The isolated RNA was also suitable for downstream applications, such as reverse transcription-polymerase chain reaction (RT-PCR) and quantitative RT-PCR (RT-qPCR). The RNA isolation method was also efficient for recalcitrant plant tissues.
Biotechnol Biotechnol Equip
· 2014 Nov · PMID 26019586
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The increasing demand for energy has led to the development of biomass conversion technologies. As the most abundant biomass on Earth, cellulose is generally chosen as the primary research target for biomass conversion....The increasing demand for energy has led to the development of biomass conversion technologies. As the most abundant biomass on Earth, cellulose is generally chosen as the primary research target for biomass conversion. In this review, gasification and pyrolysis of cellulose are briefly discussed and hydrolysis is then considered in detail. Moreover, many new developments and applications are introduced in cellulose conversion in recent years. Among these technologies, heterogeneous catalysis, hydrolysis in ionic liquid and hydrolysis by hot-compressed water exhibit a promising potential in cellulose conversion. Therefore, they are well recognized as powerful, fast and efficient techniques, becoming the focus of intensive research.
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019585
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In this work a neuro-fuzzy based model of a whey batch fermentation process by a strain var. MC5 is presented. A three-layered neuro-fuzzy network is realized. The simulation results are compared with conventional mode...In this work a neuro-fuzzy based model of a whey batch fermentation process by a strain var. MC5 is presented. A three-layered neuro-fuzzy network is realized. The simulation results are compared with conventional models (based on mass balance and differential equations). The neuro-fuzzy model provides a better fitness and allows inclusion of linguistic variables (such as colour, smell, taste, morphophysiology, etc.). The accuracy is approximately equal to this achieved by a conventional neural network. The proposed approach is flexible (with regard to the process model) and quite robust (with regard to the possible uncertainties and to the optimization surface). Future work will focus on applying this approach for modelling of different biotechnological processes.
Stojanov D, Koceski S, Mileva A
… +2 more, Koceska N, Bande CM
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019584
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In order to facilitate and speed up the search of massive DNA databases, the database is indexed at the beginning, employing a mapping function. By searching through the indexed data structure, exact query hits can be id...In order to facilitate and speed up the search of massive DNA databases, the database is indexed at the beginning, employing a mapping function. By searching through the indexed data structure, exact query hits can be identified. If the database is searched against an annotated DNA query, such as a known promoter consensus sequence, then the starting locations and the number of potential genes can be determined. This is particularly relevant if unannotated DNA sequences have to be functionally annotated. However, indexing a massive DNA database and searching an indexed data structure with millions of entries is a time-demanding process. In this paper, we propose a fast DNA database indexing and searching approach, identifying all query hits in the database, without having to examine all entries in the indexed data structure, limiting the maximum length of a query that can be searched against the database. By applying the proposed indexing equation, the whole human genome could be indexed in 10 hours on a personal computer, under the assumption that there is enough RAM to store the indexed data structure. Analysing the methodology proposed by Reneker, we observed that hits at starting positions [Formula: see text] are not reported, if the database is searched against a query shorter than [Formula: see text] nucleotides, such that [Formula: see text] is the length of the DNA database words being mapped and [Formula: see text] is the length of the query. A solution of this drawback is also presented.
Sudi IY, Shamsir MS, Jamaluddin H
… +2 more, Wahab RA, Huyop F
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019583
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The D-2-haloacid dehalogenase of D-specific dehalogenase (DehD) from sp. RC1 catalyses the hydrolytic dehalogenation of D-haloalkanoic acids, inverting the substrate-product configuration and thereby forming the corresp...The D-2-haloacid dehalogenase of D-specific dehalogenase (DehD) from sp. RC1 catalyses the hydrolytic dehalogenation of D-haloalkanoic acids, inverting the substrate-product configuration and thereby forming the corresponding L-hydroxyalkanoic acids. Our investigations were focused on DehD mutants: R134A and Y135A. We examined the possible interactions between these mutants with haloalkanoic acids and characterized the key catalytic residues in the wild-type dehalogenase, to design dehalogenase enzyme(s) with improved potential for dehalogenation of a wider range of substrates. Three natural substrates of wild-type DehD, specifically, monochloroacetate, monobromoacetate and D,L-2,3-dichloropropionate, and eight other non-natural haloalkanoic acids substrates of DehD, namely, L-2-chloropropionate; L-2-bromopropionate; 2,2-dichloropropionate; dichloroacetate; dibromoacetate; trichloroacetate; tribromoacetate; and 3-chloropropionate, were docked into the active site of the DehD mutants R134A and Y135A, which produced altered catalytic functions. The mutants interacted strongly with substrates that wild-type DehD does not interact with or degrade. The interaction was particularly enhanced with 3-chloropropionate, in addition to monobromoacetate, monochloroacetate and D,L-2,3-dichloropropionate. In summary, DehD variants R134A and Y135A demonstrated increased propensity for binding haloalkanoic acid and were non-stereospecific towards halogenated substrates. The improved characteristics in these mutants suggest that their functionality could be further exploited and harnessed in bioremediations and biotechnological applications.
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019582
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Prebiotics are defined as food components that confer health benefits on the host through modulation of the microbiota. Xylooligosaccharides (XOS) are non-digestible oligosaccharides that have recently received increasin...Prebiotics are defined as food components that confer health benefits on the host through modulation of the microbiota. Xylooligosaccharides (XOS) are non-digestible oligosaccharides that have recently received increasing attention as potential prebiotic candidates. XOS are sugar oligomers composed of 1,4-linked xylopyranosyl backbone and are obtained by either chemical or, more commonly, enzymatic hydrolysis of xylan polysaccharides, extracted from the plant cell wall. The bifidogenic effect of XOS was demonstrated by both in vitro studies and small-scale in vivo human studies. Some intestinal bacterial strains are able to grow on XOS, yet numerous studies have demonstrated that the ability to utilize these oligosaccharides varies considerably among these bacteria. The aim of this study is to investigate the ability of several strains to use XOS. Fifteen strains, allifiated to , and , were studied. Screening procedure was performed for the ability of the strains to utilize XOS as an alternative carbon source. Only some of them utilize XOS. The growth kinetics show the presence of two lag phases, indicating that these bacteria utilize probably some monosaccharides present in the used XOS. XOS were fermented with high specificity by strains, but did not metabolize XOS efficiently.
Pervaiz I, Ahmad S, Khaliq FH
… +10 more, Arshad A, Imran M, Khan BA, Ullah A, Ali U, Iqbal K, Usman M, Bibi H, Khan NU, Mahmood W
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019581
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Structural transformation of ezetimibe was performed by fungi and . The metabolites were identified by different spectroscopic techniques as (3R,4S)-1-(4-fluorophenyl)-3-((E)-3-(4-fluorophenyl) allyl)-4-(4-hydroxyphenyl...Structural transformation of ezetimibe was performed by fungi and . The metabolites were identified by different spectroscopic techniques as (3R,4S)-1-(4-fluorophenyl)-3-((E)-3-(4-fluorophenyl) allyl)-4-(4-hydroxyphenyl) azetidin-2-one (2), (3R, 4S)-1-(4-fluorophenyl)-3-(3-(4fluorophenyl)-3-oxopropyl)-4-(4-hydroxyphenyl) azetidin-2-one (3), (3R,4S) 1-(4-fluorophenyl)-3-(3-(4-fluorophenyl) propyl)-4-(4-hydroxyphenyl) azetidin-2-one (4) and (2R,5S)-N, 5-bis (4-fluorophenyl)-5-hydroxy-2-(4-hydroxybenzyl) pentanamide (5). This study displays two important features of these fungi, viz., their ability to metabolize halogenated compounds, and their capacity to metabolize drugs that are targets of the UDP-Glucuronyl Transferase System, a phenomenon not commonly observed.
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019580
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The aim of this study was to clinically assess the therapeutic effect of low-level laser therapy (LLLT) on chronic recurrent aphthous stomatitis (RAS) using a protocol we developed especially for the purpose. The study i...The aim of this study was to clinically assess the therapeutic effect of low-level laser therapy (LLLT) on chronic recurrent aphthous stomatitis (RAS) using a protocol we developed especially for the purpose. The study included 180 patients: group 1 (the study group) - 90 patients who received LLLT using a laser operating in the red spectrum (658 nm; in a non-contact mode; power output = 27 mW; frequency = 5.8 Hz, - continuous waveform; time = 1.14 min; dosage of 2 J/cm once daily); group 2 (controls) - 90 patients who received pharmacotherapy (Granofurin and solcoseryl given twice daily). The indices we assessed were pain intensity, erythema dynamics and epithelization time. Pain was completely managed in 55.6% of group 1 patients one day after therapy began, while it took three days to alleviate pain for 11.1% of the patients in group 2. The erythema was managed entirely in 24.4% of group 1 patients after the first session, while it did not change in any of the group 2 patients. Pain intensity and erythema had similar dynamics for both groups. In 5 days, 75.6% of group 1 patients showed complete epithelization, while in group 2 the process was completed in only 37.8% of patients. As a whole, the results we obtained using LLLT to treat chronic RAS were better than those obtained in the group receiving pharmacotherapy. Pain and inflammation were very effectively managed with LLLT with the parameters we used and epithelization was considerably accelerated.
Wang L, Sun Y, Ruan C
… +3 more, Liu B, Zhao L, Gu X
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019579
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The aim of this study was to investigate the therapeutic effect of on a rat model of diffuse interstitial pulmonary fibrosis induced by bleomycin A5. The mechanism by which exerts its effect is also discussed. A diffus...The aim of this study was to investigate the therapeutic effect of on a rat model of diffuse interstitial pulmonary fibrosis induced by bleomycin A5. The mechanism by which exerts its effect is also discussed. A diffuse interstitial pulmonary fibrosis model was established in 36 male Wistar rats by an endotracheal injection of bleomycin A5 (5 mg/kg). Then, these rats were randomly divided into the model group ( = 18) and the treatment group (treated with after modelling, = 18). Control rats ( = 6) received an equal volume of saline. Hematoxylin-eosin (HE) staining was performed to analyse alveolitis and Masson staining, to observe pulmonary fibrosis. Collagen content was determined by hydroxyproline assay. Nuclear factor kappa B (NF-κB) activity was measured by electrophoretic mobility shift assay. Transforming growth factor-β (TGF-β) expression at mRNA level was detected by northern blotting and at protein level by enzyme-linked immunosorbent assay. The results obtained showed that the alveolitis and pulmonary fibrosis of the rats treated with was significantly alleviated compared with that of the rats in the model group. Treatment with also lowered the content of collagen, decreased NF-κB activity in alveolar macrophages and reduced the TGF-β expression at the mRNA and protein level. These results indicated that is effective in treating and alleviating interstitial pulmonary fibrosis, possibly by lowering collagen, inhibiting the activity of NF-κB and reducing the TGF-β expression.
Doumanov J, Mladenova K, Aleksandrov R
… +2 more, Danovski G, Petrova S
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019578
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Secreted Phospholipases A (sPLAs) represent a large family of structurally related enzymes, which target different tissues and organs and induce numerous pharmacological effects based on their catalytic specificity - hyd...Secreted Phospholipases A (sPLAs) represent a large family of structurally related enzymes, which target different tissues and organs and induce numerous pharmacological effects based on their catalytic specificity - hydrolysis of the -2 ester bond of glycerophospholipids. The neurotoxin vipoxin, isolated from the venom of , is a heterodimeric postsynaptic ionic complex composed of two protein subunits - a basic and toxic His48 sPLA enzyme and an acidic, enzymatically inactive and non-toxic component. In this paper, for the first time, we demonstrate that vipoxin sPLA enzyme affects cell integrity and viability of four cell types and causes different cell responses. The most dramatic local tissue effects were observed with RPE-1 (retinal pigment epithelial) cells followed by A549 (adenocarcinomic human alveolar epithelial) cells and MDCK (Madin-Darby Canine Kidney epithelial) cells. Products of the enzymatic reaction, lysophospholipids and unsaturated free fatty acids, act as lipid mediators that can induce membrane damaging or can stimulate cell proliferation. Our preliminary results on the cytotoxic effect of vipoxin sPLA on A549 cells are promising in searching of its eventual anticancer potential.
Stanilov N, Miteva L, Dobreva Z
… +1 more, Stanilova S
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019577
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Colorectal cancer (CRC) development is strongly associated with innate immune mechanisms and intestinal inflammation. The aim of the study was to investigate the pre-operative serum levels of TNF-α and its correlation wi...Colorectal cancer (CRC) development is strongly associated with innate immune mechanisms and intestinal inflammation. The aim of the study was to investigate the pre-operative serum levels of TNF-α and its correlation with cancer progression and survival in CRC patients taking into account the genotype of -308G/A promoter polymorphism in TNF-α gene (rs1800629). TNF-α -308G/A genotypes of 119 CRC cases and 177 no CRC controls were determined by restriction fragment length polymorphism assay (RFLP-PCR). TNF-α serum levels were measured by enzyme-linked immunosorbent assay (ELISA). Although no significant differences in allele and genotype frequencies between CRC and controls were observed, it should be noted that the minor allele-A and its homozygous genotype were overrepresented among CRC. In addition, allele-A was more frequent in early CRC patients compared to advanced cases. TNF-α serum level was significantly higher in CRC patients than in controls (36.1 ± 8.4 pg/mL vs. 18.66 ± 11 pg/mL; = 0.0000001). In the subgroup analysis by tumour-node-metastasis stages, the highest TNF-α level was found in stage IV (42.7 ± 12.5 pg/mL) and was significantly elevated compared to earlier stages of CRC and controls. The survival rate of CRC patients with low TNF-α serum level, estimated as median survival, was significantly higher than that of patients with high levels of TNF-α (38.4 vs. 7.761 months; log rank test = 0.00015) In conclusion, we can affirm that TNF-α affects tumour development along with disease progression which has an impact on the survival of CRC.
Vlaykova T, Kurzawski M, Tacheva T
… +5 more, Dimov D, Gulubova M, Yovchev Y, Chakarov S, Drozdzik M
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019576
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Coetaneous malignant melanoma is the most aggressive cancer of the skin with a high rate of mortality worldwide. Degradation of basement membranes and extracellular matrix is an essential step in cancer invasion and meta...Coetaneous malignant melanoma is the most aggressive cancer of the skin with a high rate of mortality worldwide. Degradation of basement membranes and extracellular matrix is an essential step in cancer invasion and metastasis. Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) play key roles in this step. MMP-3 also called stromelysin-1 was one of the first proteinases found to be associated with cancer. In the gene of MMP-3 ), an insertion/deletion of an A nucleotide at position -1171 in promoter region has been identified and shown to effect the expression activity of the gene. The present study was conducted to investigate the relation of polymorphism with skin malignant melanoma risk in a pilot case-control study of Bulgarian patients (n = 26) and unaffected controls (n = 172). The genotypes of controls and melanoma patients were in Hardy-Weinberg equilibrium. The results showed no statistically significant difference both in genotype and allele frequencies of polymorphism between melanoma patients and healthy controls either in crude analyses (p = 0.360 and 0.790, c2-test) or after adjustment for age and sex. The comparison of some clinical characteristics between the patients with different genotypes showed a trend for longer survival of patients with genotype compared to the carriers of allele ( genotypes, p = 0.118, Log rank test). The results of our current preliminary study do not provide evidence for the role of the promoter polymorphism in as a risk factor for development of coetaneous melanoma, but suggest its implication in progression of the diseases.
Urshev Z, Ninova-Nikolova N, Ishlimova D
… +3 more, Pashova-Baltova K, Michaylova M, Savova T
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019575
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Among cultures, the principle component of yoghurt and cheese starters, a minority of strains forms the group of 'H'-strains which show an unusually high acidification rate, grow faster and coagulate milk 3-5 hours earl...Among cultures, the principle component of yoghurt and cheese starters, a minority of strains forms the group of 'H'-strains which show an unusually high acidification rate, grow faster and coagulate milk 3-5 hours earlier than the typical cultures. A large-scale screening study was performed to select 'H'-strains of from more than 100 samples of home-made yoghurt, industrial yoghurt starters and single cultures, maintained in the LBB culture collection. Only four strains - LBB.TN1, LBB.M23, LBB.M34 and LBB.M60 - were isolated/selected due to their ability to form large yellowish colonies on milk agar, supplemented with beta-glycerophosphate and bromocresol purple. While in general is described as a species with limited proteolytic capacity and in contrast to all other tested cultures, the four selected strains invariably gave positive amplification product with the polymerase chain reaction when primers, specific for the membrane proteinase-coding gene S were used. The macrorestriction profiles of the genomic DNA of the four strains confirmed that they are non-isogenic and not related to each other. When grown in milk and compared to the control industrial strain LBB.A, the four strains showed a dramatically faster acidification, coagulating milk within four hours. The application of strain TN1 or M23 as adjunct culture to industrial yoghurt starter LBB.BY5-12 resulted in shortening the fermentation time with more than 30 min.
Denkova R, Ilieva S, Denkova Z
… +4 more, Georgieva L, Yordanova M, Nikolova D, Evstatieva Y
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019574
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In order for the beneficial effects of sourdough application in breadmaking to take place a proper selection of lactic acid bacteria species and strains, an appropriate technology and effective control of the purity and...In order for the beneficial effects of sourdough application in breadmaking to take place a proper selection of lactic acid bacteria species and strains, an appropriate technology and effective control of the purity and activity of the selected cultures. Four symbiotic starters for sourdough for the production of bread were developed and probated in a production laboratory using the selected strains LBRZ7, LBRZ6, X2, RN5, R and LBRH10 and the probiotic strain Propionibacterium freudenreichii ssp. shermanii NBIMCC 327. The starter sourdoughs that include ssp. shermanii NBIMCC 327 had greater antimicrobial activity against saprophytic microorganisms: . and sp., but none of them inhibited the growth of bakery yeasts . It was established that in order to prevent bacterial spoilage 10% of the selected starter sourdoughs had to be added in the breadmaking process, while for prevention of mold spoilage the necessary amount of starter sourdough had to be between 15% and 20%.The application of the developed starters for the production of wheat bread guarantees longer shelf life and no adverse alterations in the features of the final bread.
Yang L, Fu S, Peng X
… +3 more, Li L, Song T, Li L
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019573
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In this study, a one-step, real-time, loop-mediated isothermal amplification (RealAmp) assay was developed, for the highly specific detection of pork DNA. For the assay, the mtDNA of () gene was amplified at 63 °C using...In this study, a one-step, real-time, loop-mediated isothermal amplification (RealAmp) assay was developed, for the highly specific detection of pork DNA. For the assay, the mtDNA of () gene was amplified at 63 °C using SYBR Green I for 45 min with a Real-Time Polymerase Chain Reaction (PCR) System that measured the fluorescent signal at one-minute intervals. As little as 1 pg of template DNA could be detected, without any cross-reactivity with non-target species. Meat mixtures, heat-treated at 100 °C for 15 min, prepared by mixing pork meat with beef at different ratios (0.01%-10%) were tested, and the RealAmp assays allowed the detection of as little as 0.01% pork in the meat mixtures. Thus, this work showed that RealAmp could be used for specific identification and sensitive quantification of meat species, even for heat-treated meat products.
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019572
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Improvement of production of an extracellular β-glucosidase with high activity by PSY-001 was performed by using recursive protoplast fusion in a genome-shuffling format. The initial population was generated by ultravio...Improvement of production of an extracellular β-glucosidase with high activity by PSY-001 was performed by using recursive protoplast fusion in a genome-shuffling format. The initial population was generated by ultraviolet irradiation, ultrasonic mutagenesis and, then, subjected to recursive protoplast fusion. Mutant strains exhibiting significantly higher β-glucosidase activities in liquid media were isolated. The best mutant strain showed increased cell growth in a flask culture, as well as increased β-glucosidase production. A recombinant strain, F3-25, was obtained after three rounds of genome shuffling and its production of β-glucosidase activity reached 4790 U L, which was a nearly eightfold increase compared to the original strain PSY-001. The subculture experiments indicated that F3-25 was genetically stable.
Dimitrova R, Nenova E, Uzunov B
… +2 more, Shishiniova M, Stoyneva M
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019571
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Vaya (Ramsar site, protected area and Natura 2000 site) is the biggest natural lake in Bulgaria and the shallowest Black Sea coastal lake, which during the last decades has undergone significant changes and was included...Vaya (Ramsar site, protected area and Natura 2000 site) is the biggest natural lake in Bulgaria and the shallowest Black Sea coastal lake, which during the last decades has undergone significant changes and was included as critically endangered in the Red List of Bulgarian Wetlands. Our studies were conducted during the summer and autumn months of three years - 2004-2006. The paper presents results on the phytoplankton abundance (numbers, biomass and carbon content) in combination with the indices of species diversity, evenness and dominance. Phytoplankton abundance was extremely high (average values of 1135 × 10 cells/L for the quantity and of 46 mg/L for the biomass) and increased in the end of the studied period (years 2005-2006), when decrease of species diversity and increase of the dominance index values were detected. The carbon content of the phytoplankton was at an average value of 9.7 mg/L and also increased from 2004 to 2006. Cyanoprokaryota dominated in the formation of the total carbon content of the phytoplankton, in its numbers (88%-97.8%), and in the biomass (62%-87.9%). All data on phytoplankton abundance and structural parameters in Vaya confirm the hypertrophic status of the lake and reflect the general negative trend in its development.
Lazarova N, Krumova E, Stefanova T
… +2 more, Georgieva N, Angelova M
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019570
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Despite the intensive research in the past decade on the microbial bioaccumulation of heavy metals, the significance of redox state for oxidative stress induction is not completely clarified. In the present study, we exa...Despite the intensive research in the past decade on the microbial bioaccumulation of heavy metals, the significance of redox state for oxidative stress induction is not completely clarified. In the present study, we examined the effect of redox-active (copper and chromium) and redox-inactive (cadmium) metals on the changes in levels of oxidative stress biomarkers and antioxidant enzyme defence in R57 cells. This filamentous yeast strain showed significant tolerance and bioaccumulation capability of heavy metals. Our findings indicated that the treatment by both redox-active and redox-inactive heavy metal induced oxidative stress events. Enhanced concentrations of Cu, Cr and Cd caused acceleration in the production of reactive oxygen species (ROS), increase in the level of oxidatively damaged proteins and accumulation of reserve carbohydrates (glycogen and trehalose). Cell response against heavy metal exposure also includes elevation in the activities of antioxidant enzymes, superoxide dismutase and catalase, which are key enzymes for directly scavenging of ROS. Despite the mentioned changes in the stress biomarkers, did not show a significant growth diminution. Probably, activated antioxidant defence contributes to the yeast survival under conditions of heavy metal stress.
Gemishev O, Zapryanov S, Blagoev A
… +2 more, Markova M, Savov V
Biotechnol Biotechnol Equip
· 2014 Sep · PMID 26019569
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Bioconversion of cellulose-containing substrate to glucose represents an important area of modern biotechnology. Enzymes for the degradation of the polysaccharide part of biomass have been produced, mostly by fungi belon...Bioconversion of cellulose-containing substrate to glucose represents an important area of modern biotechnology. Enzymes for the degradation of the polysaccharide part of biomass have been produced, mostly by fungi belonging to genus . Studies were carried out with the mutant strain M7, a cellulase producer. Spores of the enzyme producer were irradiated with different doses of characteristic X-ray radiation from metallic tungsten (mainly the W Kα1 and Kα2 lines) with a high dose rate. The latter is a specific property of the dense plasma focus (DPF) device, which has pulsed operation and thus gives short and highly energetic pulses of multiple types of rays and particles. In this case, we focused our study on the influence of hard X-rays. The doses of X-rays absorbed by the spores varied in the range of approximately 5-11,000 mSv measured with thermoluminescent dosimeters (TLD). The influence of the applied doses in combination with exceptionally high dose rates (in the order of tens of millisieverts per microsecond) on the activity of the produced endoglucanase, amount of biomass and extra-cellular protein, was studied in batch cultivation conditions. In the dose range of 200-1200 mSv, some enhancement of endoglucanase activity was obtained: around 18%-32%, despite the drop of the biomass amount, compared with the untreated material.