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1.
Chromium uptake bySaccharomyces cerevisiae and isolation of glucose tolerance factor from yeast biomass 总被引:2,自引:0,他引:2
Vlatka Gulan Zetic Vesna Stehlik-Tomas Slobodan Grba Lavoslav Lutilsky Damir Kozlek 《Journal of biosciences》2001,26(2):217-223
Fermentations with yeastSaccharomyces cerevisiae in semiaerobic and in static conditions with the addition of chromic chloride into the used molasses medium were analysed.
It was proved that the addition of optimal amounts of CrCl3 into the basal medium enhanced the kinetics of alcohol fermentations. The addition of 200 mg/l CrCl3 into the medium stimulated both the yeast growth and the ethanol production in all experimental conditions. On the other
hand, the results showed that Cr3+ ions were incorporated into yeast cells during fermentation. Under these conditions the accumulation of Cr3+ ions was performed by yeast cells during the exponential growth phase, and with enriched amounts of 30–45 (μg/gd.m. of cells.
Yeast biomass enriched with chromium ions was extracted with 01 mol/l NH4OH assuming that the extracts had the glucose tolerance factor (GTF). Then the extracts were passed through a gel-filtration
column in order to isolate and purify the GTF. The presence of GTF in the purified fractions was determined by measuring the
absorbance at 260 nm.
It is evident from the obtained results that the added purified fractions enhanced the rates of CO2 production as well as the glucose utilization during alcoholic fermentation. As expected, the enhancement of both rates depended
on the amounts of extracts added to the fermentation substrate. Thus, it is evident that purified extracts contained the GTF
compound, and that Cr3+ ions were bonded to the protein molecule. 相似文献
2.
Simulation of direct shear tests on rooted and non-rooted soil using finite element analysis 总被引:8,自引:0,他引:8
Slobodan B. Mickovski Alexia StokesRens van Beek Murielle GhestemThierry Fourcaud 《Ecological Engineering》2011,37(10):1523-1532
The finite element (FE) method has been used in recent years to simulate overturning processes in trees and to better comprehend plant anchorage mechanics. We aimed at understanding the fundamental mechanisms of root-soil reinforcement by simulating direct shear of rooted and non-rooted soil. Two- (2D) and three-dimensional (3D) FE simulations of direct shear box tests were carried out using readily available software for routine strength assessment of the root-soil composite. Both rooted and non-rooted blocks of soil were modelled using a simplified model of root distribution and root material properties representative of real roots. Linear elastic behaviour was assumed for roots and the soil was modelled as an ideally plastic medium. FE analysis showed that direct shear tests were dependent on the material properties specified for both the soil and roots. 2D and 3D simulations of direct shear of non-rooted soil produced similar results and any differences between 2D and 3D simulations could be explained with regard to the spatial complexity of roots used in the root distribution model. The application of FE methods was verified through direct shear tests on soil with analogue roots and the results compared to in situ tests on rooted soil in field conditions. 相似文献
3.
Lovorka Grgurevic Boris Macek Mladen Mercep Mislav Jelic Tomislav Smoljanovic Igor Erjavec Ivo Dumic-Cule Stefan Prgomet Dragan Durdevic Drazen Vnuk Marija Lipar Marko Stejskal Vera Kufner Jelena Brkljacic Drazen Maticic Slobodan Vukicevic 《Biochemical and biophysical research communications》2011,(1):80
Members of the astacin family of metalloproteinases such as human bone morphogenetic protein 1 (BMP-1) regulate morphogenesis by processing precursors to mature functional extracellular matrix (ECM) proteins and several growth factors including TGFβ, BMP2, BMP4 and GFD8. We have recently discovered that BMP1-3 isoform of the Bmp-1 gene circulates in the human plasma and is significantly increased in patients with acute bone fracture. We hypothesized that circulating BMP1-3 might have an important role in bone repair and serve as a novel bone biomarker. When administered systemically to rats with a long bone fracture and locally to rabbits with a critical size defect of the ulna, recombinant human BMP1-3 enhanced bone healing. In contrast, neutralization of the endogenous BMP1-3 by a specific polyclonal antibody delayed the bone union. Invitro BMP1-3 increased the expression of collagen type I and osteocalcin in MC3T3-E1 osteoblast like cells, and enhanced the formation of mineralized bone nodules from bone marrow mesenchymal stem cells. We suggest that BMP1-3 is a novel systemic regulator of bone repair. 相似文献
4.
Length-dependent prediction of protein intrinsic disorder 总被引:2,自引:0,他引:2
Kang Peng Predrag Radivojac Slobodan Vucetic A Keith Dunker Zoran Obradovic 《BMC bioinformatics》2006,7(1):208-17
Background
Due to the functional importance of intrinsically disordered proteins or protein regions, prediction of intrinsic protein disorder from amino acid sequence has become an area of active research as witnessed in the 6th experiment on Critical Assessment of Techniques for Protein Structure Prediction (CASP6). Since the initial work by Romero et al. (Identifying disordered regions in proteins from amino acid sequences, IEEE Int. Conf. Neural Netw., 1997), our group has developed several predictors optimized for long disordered regions (>30 residues) with prediction accuracy exceeding 85%. However, these predictors are less successful on short disordered regions (≤30 residues). A probable cause is a length-dependent amino acid compositions and sequence properties of disordered regions. 相似文献5.
Srdjan Ljubisavljevic Ivana Stojanovic Slobodan Vojinovic Dragan Stojanov Svetlana Stojanovic Tatjana Cvetkovic Dejan Savic Dusica Pavlovic 《Neurochemistry international》2013
Advanced oxidation protein products (AOPP) and total thiol (SH) groups levels in plasma and CSF were studied in a cohort of 50 clinically isolated syndrome (CIS) and 57 relapsing remittent multiple sclerosis (RRMS) patients related to 20 control group (CG) patients’ values. The obtained results were compared regarding patients demographic, biochemical, clinical (EDSS) and MRI features (total T2 weighted lesions number and Gd enhancement lesion volume). 相似文献
6.
Jeonghan Lee Michael T. Nelson Kirstin E. Rose Slobodan M. Todorovic 《Molecular neurobiology》2013,48(2):274-280
T-type calcium channels in the dorsal root ganglia (DRG) have a central function in tuning neuronal excitability and are implicated in sensory processing including pain. Previous studies have implicated redox agents in control of T-channel activity; however, the mechanisms involved are not completely understood. Here, we recorded T-type calcium currents from acutely dissociated DRG neurons from young rats and investigated the mechanisms of CaV3.2 T-type channel modulation by S-nitrosothiols (SNOs). We found that extracellular application of S-nitrosoglutathione (GSNO) and S-nitroso-N-acetyl-penicillamine rapidly reduced T-type current amplitudes. GSNO did not affect voltage dependence of steady-state inactivation and macroscopic current kinetics of T-type channels. The effects of GSNO were abolished by pretreatment of the cells with N-ethylmaleimide, an irreversible alkylating agent, but not by pretreatment with 1H-(1,2,4) oxadiazolo (4,3-a) quinoxalin-1-one, a specific soluble guanylyl cyclase inhibitor, suggesting a potential effect of GSNO on putative extracellular thiol residues on T-type channels. Expression of wild-type CaV3.2 channels or a quadruple Cys-Ala mutant in human embryonic kidney cells revealed that Cys residues in repeats I and II on the extracellular face of the channel were required for channel inhibition by GSNO. We propose that SNO-related molecules in vivo may lead to alterations of T-type channel-dependent neuronal excitability in sensory neurons and in the central nervous system in both physiological and pathological conditions such as neuronal ischemia/hypoxia. 相似文献
7.
8.
Zoran Stanimirovic Jevrosima Stevanovic Slobodan Jovanovic Marko Andjelkovic 《Mutation Research - Genetic Toxicology and Environmental Mutagenesis》2005,588(2):152-157
Apitol®, with cymiazole hydrochloride as the active ingredient, is used in bee-keeping against the ectoparasitic mite Varroa destructor. The preparation was evaluated for genotoxicity in cultured human peripheral blood lymphocytes. Sister chromatid exchange, the mitotic index and the cell proliferation index were determined for three experimental concentrations of Apitol® (0.001, 0.01 and 0.1 mg/ml). All concentrations significantly (p < 0.001) increased the mitotic index (MI = 7.35 ± 0.18%, 8.31 ± 0.20% and 12.33 ± 0.25%, respectively), the proliferative index (PI = 1.83 ± 0.01, 1.84 ± 0.01 and 1.88 ± 0.02, respectively) and the frequency of sister chromatid exchange (SCE = 8.19 ± 1.81, 8.78 ± 1.80 and 13.46 ± 1.88, respectively), suggesting that cymiazole hydrochloride has genotoxic potential. 相似文献
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