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51.
Maghuly F da Câmara Machado A Leopold S Khan MA Katinger H Laimer M 《Journal of biotechnology》2007,127(2):310-321
Transgenic trees currently are being produced by Agrobacterium-mediated transformation and biolistics. Since trees are particularly suited for long-term evaluations of the impact of the technology, Prunus subhirtella autumno rosa (PAR) was chosen as model fruit tree species and transformed with a reporter gene (uidA) under the control of the 35S promoter. Using Southern and GUS fluorometric techniques, we compared transgene copy numbers and observed stability of transgene expression levels in 34 different transgenic plants, grown under in vitro, greenhouse and screenhouse conditions, over a period of 9 years. An influence of grafting on gene expression was not observed. No silenced transgenic plant was detected. Overall, these results suggest that transgene expression in perennial species, such as fruit trees, remains stable in time and space, over extended periods and in different organs, confirming the value of PAR as model species to study season-dependent regulation in mature stone fruit tissues. While the Agrobacterium-derived Prunus transformants contained one to two copies of the transgenes, 91% of the transgenic events also contained various lengths of the bacterial plasmid backbone, indicating that the Agrobacterium-mediated transformation is not as precise as previously perceived. The implications for public acceptance and future applications are discussed. 相似文献
52.
Marian Pavelka Manuel Acosta Michal V. Marek Werner Kutsch Dalibor Janous 《Plant and Soil》2007,292(1-2):171-179
The parameter Q10 is commonly used to express the relationship between soil CO2 efflux and soil temperature. One advantage of this parameter is its application in a model expression of respiration losses
of different ecosystems. Correct specification of Q10 in these models is indispensable. Soil surface CO2 efflux and soil temperature at different depths were measured in a 21-year-old Norway spruce stand and a mountain grassland
site located at the Experimental Ecological Study Site Bily Kriz, Beskydy Mts. (NE Czech Republic), using automated gasometric
systems. A time-delay and goodness-of-fit between soil CO2 efflux and soil temperature at different measuring depths were determined. Wide ranges of values for the time-delay of CO2 efflux in response to temperature, Q10 and the determination coefficient (R2) between CO2 efflux and temperature were obtained at the both sites. The values of Q10 and the CO2 time-delay increased with depth, while the R2 of the CO2-temperature relationship significantly decreased. Soil temperature records obtained close to the soil surface showed the
highest values of R2 and the lowest value of the time-delay at both sites. Measurement of soil temperature at very shallow soil layer, preferably
at the soil surface, is highly recommended to determine useable values of Q10. We present a new procedure to normalize Q10 values for soil temperatures measured at different depths that would facilitate comparison of different sites. 相似文献
53.
Kincaid EZ Wolf AJ Desvignes L Mahapatra S Crick DC Brennan PJ Pavelka MS Ernst JD 《Journal of immunology (Baltimore, Md. : 1950)》2007,179(5):3187-3195
Mycobacterium tuberculosis is an exceptionally successful human pathogen. A major component of this success is the ability of the bacteria to infect immunocompetent individuals and to evade eradication by an adaptive immune response that includes production of the macrophage-activating cytokine, IFN-gamma. Although IFN-gamma is essential for arrest of progressive tuberculosis, it is insufficient for efficacious macrophage killing of the bacteria, which may be due to the ability of M. tuberculosis to inhibit selected macrophage responses to IFN-gamma. In vitro studies have determined that mycobacterial lipoproteins and other components of the M. tuberculosis cell envelope, acting as agonists for TLR2, inhibit IFN-gamma induction of MHC class II. In addition, M. tuberculosis peptidoglycan and IL-6 secreted by infected macrophages inhibit IFN-gamma induction of MHC class II in a TLR2-independent manner. To determine whether TLR2-dependent inhibition of macrophage responses to IFN-gamma is quantitatively dominant over the TLR2-independent mechanisms in vivo, we prepared mixed bone marrow chimeric mice in which the hemopoietic compartment was reconstituted with a mixture of TLR(+/+) and TLR2(-/-) cells. When the chimeric mice were infected with M. tuberculosis, the expression of MHC class II on TLR2(+/+) and TLR2(-/-) macrophages from the lungs of individual infected chimeric mice was indistinguishable. These results indicate that TLR2-dependent and -independent mechanisms of inhibition of responses to IFN-gamma are equivalent in vivo, and that M. tuberculosis uses multiple pathways to abrogate the action of an important effector of adaptive immunity. This work was supported by National Institutes of Health Grants AI 065357-AI 020010. 相似文献
54.
Padavattan S Schirmer T Schmidt M Akdis C Valenta R Mittermann I Soldatova L Slater J Mueller U Markovic-Housley Z 《Journal of molecular biology》2007,368(3):742-752
The major allergens of honeybee venom, hyaluronidase (Hyal) and phospholipase A2, can induce life-threatening IgE-mediated allergic reactions in humans. Although conventional immunotherapy is effective, up to 40% of patients develop allergic side effects including anaphylaxis and thus, there is a need for an improved immunotherapy. A murine monoclonal anti-Hyal IgG1 antibody (mAb 21E11), that competed for Hyal binding with IgEs from sera of bee venom allergic patients, was raised. The fragment of these IgG antibodies which bind to antigen (Fab) was produced and complexed (1:1) with Hyal. The crystal structure determination of Hyal/Fab 21E11 complex (2.6 A) enabled the identification of the Hyal-IgG interface which provides indirect information on the Hyal-IgE interaction (B-cell epitope). The epitope is composed of a linear array of nine residues (Arg138, His141-Arg148) located at the tip of a helix-turn-helix motive which protrudes away from the globular core and fits tightly into the deep surface pocket formed by the residues from the six complementarity determining regions (CDRs) of the Fab. The epitope is continuous and yet its conformation appears to be essential for Ab recognition, since the synthetic 15-mer peptide comprising the entire epitope (Arg138-Glu152) is neither recognized by mAb 21E11 nor by human IgEs. The structure of the complex provides the basis for the rational design of Hyal derivatives with reduced allergenic activity, which could be used in the development of safer allergen-specific immunotherapy. 相似文献
55.
In the present study the menarcheal status (pre-or postmenarcheal), body composition, weight status, and socioeconomic parameters such as type of school and parental educational level as of 1752 female adolescents ageing between 12 and 18 years (x = 14.6) from rural areas of Eastern Austria were documented. Furthermore the association patterns between body composition, socioeconomic parameters and menarcheal status were analyzed. It turned out, that body composition parameters such as BMI, lean body mass and absolute and relative fat mass were significantly associated with menarcheal status. Postmenarcheal girls were taller and exhibited a higher weight status, a higher absolute and relative amount of fat mass and a higher amount of lean body mass than their premenarcheal counterparts of the same age. In contrast to the significant association between body composition and menarcheal status, no significant impact of educational level on menarcheal status, indicating socioeconomic status could be documented. 相似文献
56.
Cantin LD Magnuson S Gunn D Barucci N Breuhaus M Bullock WH Burke J Claus TH Daly M Decarr L Gore-Willse A Hoover-Litty H Kumarasinghe ES Li Y Liang SX Livingston JN Lowinger T Macdougall M Ogutu HO Olague A Ott-Morgan R Schoenleber RW Tersteegen A Wickens P Zhang Z Zhu J Zhu L Sweet LJ 《Bioorganic & medicinal chemistry letters》2007,17(10):2869-2873
Modulation of cAMP levels has been linked to insulin secretion in preclinical animal models and in humans. The high expression of PDE-10A in pancreatic islets suggested that inhibition of this enzyme may provide the necessary modulation to elicit increased insulin secretion. Using an HTS approach, we have identified quinoline-based PDE-10A inhibitors as insulin secretagogues in vitro. Optimized compounds were evaluated in vivo where improvements in glucose tolerance and increases in insulin secretion were measured. 相似文献
57.
Biodegradation of chlorobenzene under hypoxic and mixed hypoxic-denitrifying conditions 总被引:1,自引:0,他引:1
Pseudomonas veronii strain UFZ B549, Acidovorax facilis strain UFZ B530, and a community of indigenous groundwater bacteria, adapted to oxygen limitation, were cultivated on chlorobenzene
and its metabolites 2-chloro-cis,cis-muconate and acetate/succinate under hypoxic and denitrifying conditions. Highly sensitive approaches were used to maintain
defined low oxygen partial pressures in an oxygen-re-supplying headspace. With low amounts of oxygen available all cultures
converted chlorobenzene, though the pure strains accumulated 3-chlorocatechol and 2-chloro-cis,cis-muconate as intermediates. Under strictly anoxic conditions no chlorobenzene transformation was observed, while 2-chloro-cis,cis-muconate, the fission product of oxidative ring cleavage, was readily degraded by the investigated chlorobenzene-degrading
cultures at the expense of nitrate as terminal electron acceptor. Hence, we conclude that oxygen is an obligatory reactant
for initial activation of chlorobenzene and fission of the aromatic ring, but it can be partially replaced by nitrate in respiration.
The tendency to denitrify in the presence of oxygen during growth on chlorobenzene appeared to depend on the oxygen availability
and the efficiency to metabolize chlorobenzene under oxygen limitation, which is largely regulated by the activity of the
intradiol ring fission dioxygenase. Permanent cultivation of a groundwater consortium under reduced oxygen levels resulted
in enrichment of a community almost exclusively composed of members of the β-Proteobacteria and Bacteroidetes. Thus, it is deduced that these strains can still maintain high activities of oxygen-requiring enzymes that allow for efficient
CB transformation under hypoxic conditions. 相似文献
58.
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60.
Marion C. Hoepflinger Anja Geretschlaeger Aniela Sommer Margit Hoeftberger Christina Hametner Takashi Ueda Ilse Foissner 《Traffic (Copenhagen, Denmark)》2015,16(5):534-554
RAB5 GTPases are important regulators of endosomal membrane traffic. Among them Arabidopsis thaliana ARA7/RABF2b is highly conserved and homologues are present in fungal, animal and plant kingdoms. In land plants ARA7 and its homologues are involved in endocytosis and transport towards the vacuole. Here we report on the isolation of an ARA7 homologue (CaARA7/CaRABF2) in the highly evolved characean green alga Chara australis. It encodes a polypeptide of 202 amino acids with a calculated molecular mass of 22.2 kDa and intrinsic GTPase activity. Immunolabelling of internodal cells with a specific antibody reveals CaARA7 epitopes at multivesicular endosomes (MVEs) and at MVE‐containing wortmannin (WM) compartments. When transiently expressed in epidermal cells of Nicotiana benthamiana leaves, fluorescently tagged CaARA7 localizes to small organelles (putative MVEs) and WM compartments, and partially colocalizes with AtARA7 and CaARA6, a plant specific RABF1 GTPase. Mutations in membrane anchoring and GTP binding sites alter localization of CaARA7 and affect GTPase activity, respectively. This first detailed study of a conventional RAB5 GTPase in green algae demonstrates that CaARA7 is similar to RAB5 GTPases from land plants and other organisms and shows conserved structure and localization. 相似文献