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991.
Metabolism and Plant Hormone Action During Clubroot Disease 总被引:2,自引:0,他引:2
Jutta Ludwig-Müller Els Prinsen Stephen A. Rolfe Julie D. Scholes 《Journal of Plant Growth Regulation》2009,28(3):229-244
Infection of Brassicaceae with the obligate biotrophic pathogen Plasmodiophora brassicae results in the development of root galls (clubroots). During the transformation of a healthy root to a root gall a plethora
of changes in primary and secondary metabolism occur. The upper part of an infected plant is retarded in growth due to redirection
of assimilates from the shoot to the root. In addition, changes in the levels of plant growth regulators, especially auxins
and cytokinins, contribute to the hypertrophy of infected roots. Also, defense reactions are manipulated after inoculation
of suitable host plants with P. brassicae. This review summarizes our current knowledge on the changes in these parameters. A model is presented for how primary metabolism
and secondary metabolism, including plant hormones, interact to induce clubroot formation. 相似文献
992.
Ikemefuna Onyekwelu Mary B. Goldring Chisa Hidaka 《Journal of cellular biochemistry》2009,107(3):383-392
The repair of joint surface defects remains a clinical challenge, as articular cartilage has a limited healing response. Despite this, articular cartilage does have the capacity to grow and remodel extensively during pre‐ and post‐natal development. As such, the elucidation of developmental mechanisms, particularly those in post‐natal animals, may shed valuable light on processes that could be harnessed to develop novel approaches for articular cartilage tissue engineering and/or regeneration to treat injuries or degeneration in adult joints. Much has been learned through mouse genetics regarding the embryonic development of joints. This knowledge, as well as the less extensive available information regarding post‐natal joint development is reviewed here and discussed in relation to their possible relevance to future directions in cartilage tissue repair and regeneration. J. Cell. Biochem. 107: 383–392, 2009. © 2009 Wiley‐Liss, Inc. 相似文献
993.
The design of substituted lactols is described, which in their reaction with racemic alkyl aryl carbinols react preferentially with one of the enantiomers exhibiting selectivities up to 14:1. 相似文献
994.
Tetsuro Tamaki Yoshiyasu Uchiyama Yoshinori Okada Kayoko Tono Masahiro Nitta Akio Hoshi Akira Akatsuka 《Histochemistry and cell biology》2009,132(1):59-70
Tissue inflammation and multiple cellular responses in the compensatory enlarged plantaris (OP Plt) muscle induced by surgical
ablation of synergistic muscles (soleus and gastrocnemius) were followed over 10 weeks after surgery. Contralateral surgery
was performed in adult Wistar male rats. Cellular responses in muscle fibers, blood vessels and nerve fibers were analyzed
by immunohistochemistry and electron microscopy. Severe muscle fiber damage and disappearance of capillaries associated with
apparent tissue edema were observed in the peripheral portion of OP Plt muscles during the first week, whereas central portions
were relatively preserved. Marked cell activation/proliferation was also mainly observed in peripheral portions. Similarly,
activated myogenic cells were seen not only inside but also outside of muscle fibers. The former were likely satellite cells
and the latter may be interstitial myogenic cells. One week after surgery, small muscle fibers, small arteries and capillaries
and several branched-muscle fibers were evident in the periphery, thus indicating new muscle fiber and blood vessel formation.
Proliferating cells were also detected in the nerve bundles in the Schwann cell position. These results indicate that the
compensatory stimulated/enlarged muscle is a suitable model for analyzing multiple physiological cellular responses in muscle–nerve–blood
vessel units under continuous stretch stimulation.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
995.
Danit Atias Khalil Abu-Rabeah Sebastien Herrmann Julia Frenkel Dorith Tavor Serge Cosnier Robert S. Marks 《Biosensors & bioelectronics》2009,24(12):3683-3687
Herein the development of an alternative optic-conductive fiber configuration applied for the construction of biosensing platforms. This new approach is based on applying the chemical polymerization of pyrrole onto the surface of polymethyl metacrylate (PMMA) fibers to create a polymer—a conductive surface, onto which an additional photoactive polypyrrole-benzophenone (PpyBz) film is electrochemically generated upon the fiber surface. Irradiation of the benzophenone groups embedded in the Ppy films with UV radiation (350 nm) formed active radicals that allowed the covalent attachment of the desired bioreceptors. Characterization of the amperometric biosensing matrix was accomplished by using a model Urease (Urs) through electrochemical impedance spectroscopy (EIS) and amperometry. Both techniques have shown a low charge transfer resistance (340 kΩ) and a high sensitivity (12.3 μA mM−1 cm−2). Thereafter, the construction of an optical biosensing matrix based on horseradish peroxidase (HRP) production of photons was carried out. The high signal to noise (S/N) ratio (1600) indicated clearly that this approach can serve as a new platform to replace glass optical fibers based on biosensors. 相似文献
996.
Simon Hix Abdul Noury Gérard Roland 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2009,364(1518):821-831
Members of the European Parliament (MEPs) have voluntarily formed transnational political groups and invariably follow the voting instructions of these groups. This is intriguing as there are few obvious incentives for doing so. Unlike national parties, for example, the political groups in the European Parliament are not punished by the electorate if they are divided on key issues, as citizens know very little about what goes on inside the European Parliament. This paper pieces together an explanation of why the European political groups exist and why they have become so powerful by looking at the determinants of group cohesion and by undertaking a spatial analysis of voting in the European Parliament. MEPs who share preferences on a range of issues on the European Union policy agenda have an incentive to establish a division-of-labour contract and to share the costs of collecting information. Once internal party policy specialization and agenda setting has been established, MEPs have incentives to follow the voting instructions of their group owing to the advantages of cohesion in a context of repeated voting. 相似文献
997.
Gabriela Pastuch-Gawolek Tadeusz Bieg Wieslaw Szeja Jakub Flasz 《Bioorganic chemistry》2009,37(3):77-83
We present the synthesis of 1-thioglycosyl derivatives of uridine, which were designed to act as potential donor substrates for glycosyltransferases. We constructed such analogs using 5-amino-2-pyridyl 1-thioglycosides as glycosyl units which were connected to uridine via succinic linker. For preparation of the amide bonds we applied different condensation procedures. 相似文献
998.
Biological control has been attracting an increasing attention over the last two decades as an environmentally friendly alternative
to the more traditional chemical-based control. In this paper, we address robustness of the biological control strategy with
respect to fluctuations in the controlling species density. Specifically, we consider a pest being kept under control by its
predator. The predator response is assumed to be of Holling type III, which makes the system’s kinetics “excitable.” The system
is studied by means of mathematical modeling and extensive numerical simulations. We show that the system response to perturbations
in the predator density can be completely different in spatial and non-spatial systems. In the nonspatial system, an overcritical
perturbation of the population density results in a pest outbreak that will eventually decay with time, which can be regarded
as a success of the biological control strategy. However, in the spatial system, a similar perturbation can drive the system
into a self-sustained regime of spatiotemporal pattern formation with a high pest density, which is clearly a biological control
failure. We then identify the parameter range where the biological control can still be successful and describe the corresponding
regime of the system dynamics. Finally, we identify the main scenarios of the system response to the population density perturbations
and reveal the corresponding structure of the parameter space of the system.
A. Morozov is on leave from Shirshov Institute of Oceanology, Russian Academy of Science, Nakhimovsky Prosp. 36, Moscow 117218,
Russia. 相似文献
999.
Ernesto Hernández-Zapata Luciano Martínez-Balbuena Iván Santamaría-Holek 《Journal of biological physics》2009,35(3):297-308
We propose a free energy expression accounting for the formation of spherical vesicles from planar lipid membranes and derive
a Fokker–Planck equation for the probability distribution describing the dynamics of vesicle formation. We find that formation
may occur as an activated process for small membranes and as a transport process for sufficiently large membranes. We give
explicit expressions for the transition rates and the characteristic time of vesicle formation in terms of the relevant physical
parameters. 相似文献
1000.
We review winner-loser models, the currently popular explanation for the occurrence of linear dominance hierarchies, via a
three-part approach. (1) We isolate the two most significant components of the mathematical formulation of three of the most
widely-cited models and rigorously evaluate the components’ predictions against data collected on hierarchy formation in groups
of hens. (2) We evaluate the experimental support in the literature for the basic assumptions contained in winner-loser models.
(3) We apply new techniques to the hen data to uncover several behavioral dynamics of hierarchy formation not previously described.
The mathematical formulations of these models do not show satisfactory agreement with the hen data, and key model assumptions
have either little or no conclusive support from experimental findings in the literature. In agreement with the latest experimental
results concerning social cognition, the new behavioral dynamics of hierarchy formation discovered in the hen data suggest
that members of groups are intensely aware both of their own interactions as well as interactions occurring among other members of their group. We suggest that
more adequate models of hierarchy formation should be based upon behavioral dynamics that reflect more sophisticated levels
of social cognition. 相似文献