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1.
Detelin Stefanov Elisaveta Stoimenova Galina Marinova Bistra Ivanova Aglika Edreva 《Acta Physiologiae Plantarum》2012,34(1):181-190
Altered photosynthetic reactions in cucumber mosaic virus (CMV) inoculated leaves of virus resistant lines L113 and L57 and
susceptible pepper (Capsicum annuum L.) plants cv. Albena grown in controlled environment and in the field were investigated. The CMV inoculated leaves of virus
resistant lines developed different symptoms—necrotic local lesions on L113 and chlorotic spots on L57 while the same leaves
of susceptible cv. Albena were symptomless. The changes in Photosystem II (PSII) and PSI electron transport were evaluated
by chlorophyll fluorescence, and far-red (FR) light induced leaf absorbance A
810–860. CMV infection caused a decrease in maximal PSII quantum yield, F
v/F
m, in susceptible leaves. Increased non-photochemical fluorescence quenching in CMV-inoculated leaves of both resistant lines
were observed. In CMV-inoculated leaves of all tested plants FR light induced P700 oxidation was decreased. In the present
study, the viral-infected pepper plants grown in controlled environment to avoid the effects of abiotic factors were used
as model system that allow us to investigate the differences in leaf senescence in CMV-inoculated leaves of susceptible and
resistant pepper lines expressing different symptoms. Earlier leaf falls of inoculated leaves as a result of accelerated leaf
senescence is important for building successful secondary virus resistance strategy following fast responses such as hypersensitive
reaction. 相似文献
2.
Bistra Kostova Sijka Ivanova Konstantin Balashev Dimitar Rachev Darinka Christova 《AAPS PharmSciTech》2014,15(4):939-946
Segmented copolymer networks (SCN) based on poly(2-ethyl-2-oxazoline) and containing 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, and/or methyl methacrylate segments have been evaluated as potential sustained release systems of the water soluble cardioselective β-blocker metoprolol tartrate. The structure and properties of the drug carriers were investigated by differential scanning calorimetry, attenuated total reflectance Fourier transform infrared spectroscopy, scanning electron microscopy, and atomic force microscopy. Swelling kinetics of SCNs in various media was followed, and the conditions for effective MT loading were specified. MT-loaded SCNs with drug content up to 80 wt.% were produced. The release kinetics of metoprolol tartrate from the systems was studied and it was shown that the conetworks of different structure and composition are able to sustain the metoprolol tartrate release without additional excipients. 相似文献
3.
4.
Lozanov V Benkova B Mateva L Petrov S Popov E Slavov C Mitev V 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2007,860(1):92-97
A liquid chromatography method for simultaneous analysis of amino acids, polyamines, catecholeamines and metanephrines in human body fluids after derivatization with 9-fluorenylmethyloxycarbonyl chloride was developed. The chromatographic behavior of analytes at different pH of mobile phase was studied. Successful baseline resolution of all analyzed compounds was achieved using simultaneous gradient of pH and organic modifier in reverse phase mode of HPLC within 36 min. The repeatability of the proposed procedure in respect of retention time and peak area, expressed as RSD, ranges from 0.06 to 1.64% and 0.4 to 7.6%, respectively. The method linearity in the range of 1-200 microM for amino acids and in the range of 0.1-20 microM for polyamines, catecholeamines and metanephrines was found to be with correlation coefficients higher than 0.994. The limit of quantification (LOQ) was assessed to be in the range of 2.6-10 pmol for amino acids and 2-4 pmol for polyamines, catecholeamines and metanephrines. 相似文献
5.
Synthesis and properties of a new fluorescent/fluorogenic substrate Ac-DEVD-AMAC for caspase-3 are reported. The substrate
is obtained by conventional Fmoc-based solid phase peptide synthesis and its properties are investigated with regard to fluorescence,
sensitivity, applicability and kinetic constants. A non-traditional approach to assay the proteases activity using 2-aminoacridone
labeled peptides is proposed. This approach utilizes the decrease of fluorescence intensity of a sample as a measure for the
enzyme activity. 相似文献
6.
Growth responses of a tomato cultivar Ailsa Craig and the ah-, aw- and bls-isogenic/near isogenic lines (IL/NIL) from it were evaluated and compared at cotyledons stage under salt treatment in vivo and in vitro experiments. No differences in hypocotyl and root growth responses were detected between the anthocyanin-containing and the
anthocyaninless lines within the in vivo experiments. The anthocyaninless mutants, (except in some cases the bls mutant), exhibited higher callogenic and shoot-forming capacity on both, control and salinized media. It was concluded that
for this reason it would be difficult to determine the relationship between the in vivo and in vitro responses of the lines studied and as well as to evaluate the usefulness of the in vitro method in testing these lines for salt tolerance. 相似文献
7.
Bistra Atanassova 《Acta Physiologiae Plantarum》2000,22(3):221-225
Advantages and disadvantages in using functional male sterility (positional sterile — ps, positional sterile 2 — ps 2, and excerted stigma — ex) in tomato hybrid seed production and attempts to elaborate systems for their more efficacious use in breeding were discussed
in this review. It was concluded that the application of one of these types of sterility, (ps 2) in practice, although in a limited number of countries, showed the functional male sterility in tomato was a potential not
to be underestimated in developing approaches that aimed at reducting the time and cost associated with hybrid seed production. 相似文献
8.
We report the design of a MRI reporter gene with applications to non-invasive molecular imaging. We modified mitochondrial ferritin to localize to the cell cytoplasm. We confirmed the efficient cellular processing of this engineered protein and demonstrated high iron loading in mammalian cells. The reporter’s intracellular localization appears as distinct clusters that deliver robust MRI contrast. We used this new reporter to image in vivo and ex vivo the gene expression in native olfactory sensory neurons in the mouse epithelium. This robust MRI reporter can facilitate the study of the molecular mechanisms of olfaction and to monitor intranasal gene therapy delivery, as well as a wide range of cell tracking and gene expression studies in living subjects. 相似文献
9.
Effect of exercise on mRNA expression of select adrenal medullary catecholamine biosynthetic enzymes. 总被引:1,自引:0,他引:1
S Remzi Erdem Haydar A Demirel Christopher S Broxson Bistra B Nankova Esther L Sabban Nihal Tümer 《Journal of applied physiology》2002,93(2):463-468
The effect of submaximal endurance training (SET) on sympathoadrenal activity is not clear. We tested the hypothesis that SET (90 min/day, 5 days/wk, for 12 wk) elevates mRNA expression of catecholamine (CA) biosynthetic enzymes, tyrosine hydroxylase (TH) and dopamine-beta-hydroxylase (DbetaH) in the adrenal medullae of adult, female Sprague-Dawley rats. SET increased TH protein level by 35%, TH activity by 62%, TH mRNA expression by 40%, and DbetaH mRNA expression by 67%. In addition, we examined the effect of SET on Fos-related antigens (FRAs), FRA-2 immunoreactivity, and activator protein (AP)-1 binding activity. SET increased AP-1 binding activity by 78%; however, it did not affect late FRAs and FRA-2 immunoreactivity. Because the regulation of neuropeptide Y (NPY) often parallels that of CAs, we also examined the effect of SET on NPY mRNA expression. Indeed, SET elevated NPY mRNA expression as well. We conclude that 1) SET elicits a pretranslational stimulatory effect on adrenomedullary CA biosynthetic enzymes, 2) another immediate early mRNA product, rather than FRA-2, may contribute to the increase in AP-1 binding activity in response to SET, and 3) SET increases NPY mRNA expression. 相似文献
10.
Bistra Kostova Krasimira Ivanova-Mileva Dimitar Rachev Darinka Christova 《AAPS PharmSciTech》2013,14(1):352-359
Thermoresponsive amphiphilic conetworks comprising poly(2-ethyl-2-oxazoline) (PEtOx), 2-hydroxyethyl methacrylate, and 2-hydroxypropyl acrylate segments have been studied as new platforms for delivery of drug with limited solubility. Series of conetworks of varied composition were synthesized and swelling kinetics in aqueous media and ethanol were followed. The platforms were loaded with the hydrophobic drug ibuprofen by swelling in its ethanol solution. The structure and properties of the drug carriers were investigated by scanning electron microscopy and differential scanning calorimetry. The release kinetics profiles of ibuprofen from the studied platform were established. The investigation proved the feasibility of the PEtOx-based amphiphilic conetworks as highly effective platforms for sustained ibuprofen delivery. 相似文献