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161.
Vogel-Mikus K Regvar M Mesjasz-Przybyłowicz J Przybyłowicz WJ Simcic J Pelicon P Budnar M 《The New phytologist》2008,179(3):712-721
* Localization of cadmium (Cd) and other elements was studied in the leaves of the field-collected cadmium/zinc (Cd/Zn) hyperaccumulator Thlaspi praecox from an area polluted with heavy metals near a lead mine and smelter in Slovenia, using micro-PIXE (proton-induced X-ray emission). * The samples were prepared using cryofixation. Quantitative elemental maps and average concentrations in whole-leaf cross-sections and selected tissues were obtained. * Cd was preferentially localized in the lower epidermis (820 microg g(-1) DW), vascular bundles and upper epidermis, whereas about twice the lower concentrations were found in the mesophyll. * Taking into account the large volume of the mesophyll compared with the epidermis, the mesophyll is indicated as a relatively large pool of Cd, possibly involved in Cd detoxification/dilution at the tissue and cellular level. 相似文献
162.
Orlita A Sidwa-Gorycka M Kumirska J Maliński E Siedlecka EM Gajdus J Lojkowska E Stepnowski P 《Biotechnology progress》2008,24(1):128-133
The study aimed to elucidate the effects of benzothiadiazole (BTH) and saccharin on the biosynthesis of simple coumarins, linear furanocoumarins, dihydrofuranocoumarins, and furoquinolone alkaloids in shoots of R. graveolens cultivated in vitro. The biosynthesized metabolites were analyzed and identified by GC-MS and by comparison of Kovats indices. Eight coumarin metabolites were identified: bergapten, chalepin, isopimpinelin, pinnarin, psoralen, rutacultin, rutamarin, and xanthotoxin, and also four alkaloids: dictamnine, gamma-fagarine, skimmianine, and kokusaginine. Each of the tested BTH concentrations induced a significant production of furanocoumarins and furoquinolone alkaloids. The use of saccharin also increased the production of bergapten, isopimpinelin, pinnarin, psoralen, and xanthotoxin several times. 相似文献
163.
Walker A Skamel C Vorreiter J Nassal M 《The Journal of biological chemistry》2008,283(48):33508-33515
Virus capsids find increasing use as nanoparticulate platforms for the surface display of heterologous ligands, including as multivalent vaccine carriers. Presentation on the icosahedral hepatitis B virus capsid (HBcAg) is known to strongly enhance immunogenicity of foreign sequences, most efficiently if they are inserted into the dominant c/e1 B cell epitope, a surface-exposed loop in the center of the constituent core protein primary sequence. Even some complete proteins were successfully inserted but others, e.g. the outer surface protein A (OspA) of the Lyme disease agent Borrelia burgdorferi, impaired formation of capsid-like particles (CLPs). This difference can be rationalized by the requirement for the termini of the insert to fit into the predetermined geometry of the two acceptor sites in the carrier. We reasoned that cleavage of one of the two bonds connecting insert and carrier should relieve these constraints, provided the cleaved protein fragments remain competent to support the particle structure. Indeed, HBcAg CLPs containing a recognition site for tobacco etch virus (TEV) protease in the c/e1 loop remained intact after cleavage, as did CLPs carrying a 65-residue peptide insertion. Most importantly, in situ cleavage of a core-OspA fusion protein by coexpressed TEV protease strongly enhanced CLP formation compared with the uncleaved protein. These data attest to the high structural stability of the HBcAg CLP and they significantly widen its applicability as a carrier for heterologous proteins. This approach should be adaptable to any protein-based particle with surface-exposed yet sequence-internal loops. 相似文献
164.
Neuropeptide FF (NPFF) precursors from different species contain at least three known neuropeptides, i.e. FF (FLFQPQRF-NH(2)), AF (AGEGLSSPFWSLAAPQR-NH(2)) and SF (SLAAPQRF-NH(2)). We demonstrate that the rat NPFF precursor contains another bioactive sequence, NAWGPWSKEQLSPQA, spanning between positions 85 and 99. Synthetic NPFF precursor (85-99) (10 and 20 nmol, i.c.v.) blocked the expression of conditioned place preference induced by morphine (5 mg/kg, s.c.). This peptide alone (10 and 20 nmol, i.c.v.) had no influence on the baseline latency of a nociceptive reaction but reversed the antinociceptive activity of morphine (5 mg/kg, s.c.) in the tail-immersion test in rats. These data suggest the existence of a novel bioactive cryptic peptide within an already known NPFF precursor. 相似文献
165.
Jolanta Biesaga-Kocielniak Janusz Kocielniak Maria Filek Anna Janeczko 《Plant Cell, Tissue and Organ Culture》2008,94(2):139-147
The aim of this study was to produce suspension cultures of winter wheat directly from immature embryos bypassing the callus
stage, and to determine their capacity for growth and regeneration in comparison to suspension cultures produced from callus.
The study was carried out using Polish winter wheat varieties: ‘Grana’ and ‘Rosa’. Immature embryos were isolated, homogenized
and transferred directly to liquid medium supplemented with 2,4-D. Actively dividing cell cultures were obtained within 2 months
after the cultures were started. Suspension cultures from callus of immature embryos was also produced. With both cultivars,
faster growth was observed in the suspension cultures produced directly from embryos than in the suspensions produced from
callus. Metabolic activity was higher in the suspension culture produced directly from embryos than in the suspension derived
from callus only in ‘Grana’. The production of 1-amiocyclopropane-1-carboxylic acid (ACC), an ethylene precursor, was lower
in the suspension cultures produced directly from embryos than in the suspensions produced from callus. Morphogenic capacity
was significantly higher in aggregates derived directly from embryos than in aggregates derived from callus. With ‘Rosa’,
about one third of the aggregates derived directly from embryos regenerated shoots. Production of ACC was lower in ‘Rosa’
cell culture that regenerated then in other cell cultures that did not. Photosystem II reactions were more efficient in dark
green aggregates than in light green or pale green aggregates which were unable to regenerate. With the method presented,
wheat cell suspension cultures with a regeneration potential can be produced in 2 or 3 months less time than with traditional
methods. 相似文献
166.
Stecko S Jurczak M Urbańczyk-Lipkowska Z Solecka J Chmielewski M 《Carbohydrate research》2008,343(13):2215-2220
The 1,3-dipolar cycloaddition of cyclic nitrone derived from tartaric acid and (S)-5-hydroxymethyl-2(5H)-furanone leads to a single adduct which was transformed into 2,6-dihydroxyhastanecine via reaction sequence involving reduction of the lactone moiety, glycolic cleavage of the terminal diol, and the N-O hydrogenolysis followed by the intramolecular alkylation of the nitrogen atom. 相似文献
167.
Due to the variant functions that estrogens play in the regulation of reproduction, development of the mammary gland, growth
and differentiation of cells, estrogen receptors and their genes are considered as a candidates for the markers of production
and functional traits in farm animals, including cattle. In the earliest study, a 2853-bp bovine ER gene 5′-region was PCR
amplified and sequenced. Moreover, for the first time, a polymorphism was described within 5′ region of the bovine ERα gene—A/G
transition lying upstream at position 2591 from acceptor splice site +85, possibly within its promoter—which could be recognized
with RFLP-BglI. In other study we are found second polymorphism—A/G transition at position 1213 from acceptor splice site +85, located
in promoter for exon B. We have examined the specific mRNA expression of ERα in various genotypes using real-time RT-PCR.
We used four animals from each genotype group—AG, GG for BglI and AA, AG for SnaBI—to analyse liver ERα expression at the level of Real-time PCR. Liver samples were taken from the 16 young Friesian bulls
of the different ERα genotypes, slaughtered at the local abattoir. As shown by Real-Time PCR, on the livers of animals with
different genotype ERα mRNA for BglI polymorphism we didn’t found variability, but for SnaBI we have found variability between AG and AA genotypes. 相似文献
168.
The putative functions and functional efficiencies of periodic nanostructures on the surface of cicada wings have been investigated by atomic force microscopy (AFM) used as a tool for imaging, manipulation, and probing of adhesion. The structures consist of hexagonal close-packed protrusions with a lateral spacing of ∼200 nm and may have multiple functionalities. Not only do the structures confer survival value by virtue of camouflage, but they may also serve as antiwetting and self-cleaning surfaces and thus be resistant to contamination. These effects have been demonstrated by exposure to white light, liquid droplets, and AFM adhesion measurements. The dependence of optical reflectivity and surface adhesion on surface topography has been demonstrated using AFM as a nanomachining tool as well as an imaging and force-sensing probe. The intact arrays display exceptionally low adhesion for particles in the size range 20 nm-40 μm. The particles can be removed from the array by forces in the range 2-20 nN; conversely, forces in the range 25-230 nN are required to remove identical particles from a flat hydrophilic surface (i.e., polished Si). Measurements of contact angles for several liquids and particle adhesion studies show that the wing represents a low-surface-energy membrane with antiwetting properties. The inference is that a combination of chemistry and structure constitutes a natural technology for conferring resistance to contamination. 相似文献
169.
Michalska M Pajak W Kołodziejska J Lazarenkow A Nawrot-Modranka J 《Acta biochimica Polonica》2008,55(3):613-617
The synthesis and antitumour and antibacterial activity of coumarin and chromone phosphorohydrazones have been reported. This study describes influence of phosphorohydrazones derivatives of coumarin and chromone on the polymerization and viscosity of fibrin. The fibrin polymerization assay was performed by the Shen and Lorand method and the clot viscosity was measured on the basis of Shen and Lorand and Marchi and coworkers methods. Among the eight compounds tested, one coumarin derivative and two chromone derivatives showed significant activity. 相似文献
170.
Luczak-Kadlubowska A Sabat A Tambic-Andrasevic A Payerl-Pal M Krzyszton-Russjan J Hryniewicz W 《Antonie van Leeuwenhoek》2008,94(4):543-553
Staphylococcus aureus has become a major source of hospital infections and the risk of colonisation and infection by community-acquired methicillin-resistant
S. aureus (CA-MRSA) is increasingly higher. Because of the importance of S. aureus to public health, many molecular typing methods have been developed to determine its transmission routes and source of infection
during epidemiological investigations. In this study we evaluated the usefulness of multiplex PCR based Multi-Locus VNTR Fingerprinting
(MLVF) as the first step method for rapid differentiation of Croatian and Polish S. aureus isolates in hospital and community settings. This is a first report of the usefulness of MLVF in typing of hospital-acquired
methicillin-sensitive S. aureus (HA-MSSA) and four CA-MRSA isolates. A total of 47 isolates of S. aureus recovered in Croatia in 2004 and in Poland in 2006 and 2007 were tested. The MLVF results were compared to those produced
by other typing methods, such as Pulsed-Field Gel Electrophoresis (PFGE), Multi-Locus Sequence Typing (MLST) and spa typing. The MLVF analysis showed almost the same clonality results as the remaining typing methods although some differences
were found. Epidemiological data about the relation among S. aureus isolates and the results produced by typing methods applied in the present study indicate that because of the advantages
in ease and speed of Variable Number of Tandem Repeats (VNTR) procedure over PFGE, spa typing and MLST, MLVF can be used as a first screening method followed by additional typing. 相似文献