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941.
Soil water potential and temperature sum during reproductive growth control seed dormancy in Alopecurus myosuroides Huds. 下载免费PDF全文
Alexander Menegat Per Milberg Anders T. S. Nilsson Lars Andersson Giulia Vico 《Ecology and evolution》2018,8(14):7186-7194
The sustainable management of unwanted vegetation in agricultural fields through integrated weed control strategies requires detailed knowledge about the maternal formation of primary seed dormancy, to support the prediction of seedling emergence dynamics. This knowledge is decisive for the timing of crop sowing and nonchemical weed control measures. Studies in controlled environments have already demonstrated that thermal conditions and, to some extent, water availability during seed set and maturation has an impact on the level of dormancy. However, it is still unclear if this applies also under field conditions, where environmental stressors and their timing are more variable. We address this question for Alopecurus myosuroides in south‐western Sweden. We quantified the effects of cumulated temperature and precipitation as well as soil water potential during the reproductive growth phase of A myosuroides on primary seed dormancy under field conditions. Empirical models differing in focal time intervals and, in case of soil water potential, focal soil depths were compared regarding their predictive power. The highest predictive power for the level of primary dormancy of A. myosuroides seeds was found for a two‐factorial linear model containing air temperature sum between 0 and 7 days before peak seed shedding as well as the number of days with soil water potential below field capacity between 7 and 35 days before peak seed shedding. For soil water potential, it was found that only the top 10 cm soil layer is of relevance, which is in line with the shallow root architecture of A. myosuroides. We conclude that for this species the level of dormancy depends on the magnitude and timing of temperature and water availability during the reproductive growth phase. Water availability appears to be more important during maternal environmental perception and temperature during zygotic environmental perception. 相似文献
942.
943.
Debapriya Ghosh Madeline Nieves-Cintrón Sendoa Tajada Ingrid Brust-Mascher Mary C. Horne Johannes W. Hell Rose E. Dixon Luis F. Santana Manuel F. Navedo 《Biochimica et Biophysica Acta (BBA)/Molecular Cell Research》2018,1865(9):1341-1355
L-type CaV1.2 channels are key regulators of gene expression, cell excitability and muscle contraction. CaV1.2 channels organize in clusters throughout the plasma membrane. This channel organization has been suggested to contribute to the concerted activation of adjacent CaV1.2 channels (e.g. cooperative gating). Here, we tested the hypothesis that dynamic intracellular and perimembrane trafficking of CaV1.2 channels is critical for formation and dissolution of functional channel clusters mediating cooperative gating. We found that CaV1.2 moves in vesicular structures of circular and tubular shape with diverse intracellular and submembrane trafficking patterns. Both microtubules and actin filaments are required for dynamic movement of CaV1.2 vesicles. These vesicles undergo constitutive homotypic fusion and fission events that sustain CaV1.2 clustering, channel activity and cooperative gating. Our study suggests that CaV1.2 clusters and activity can be modulated by diverse and unique intracellular and perimembrane vesicular dynamics to fine-tune Ca2+ signals. 相似文献
944.
Roxana Portieles Eduardo Canales Ingrid Hernández Yunior López Mayra Rodríguez Meilyn Rodríguez Ryohei Terauchi Carlos Borroto Ramón Santos Camilo Ayra-Pardo Deqiang Zhu Xinli Liu Orlando Borrás-Hidalgo 《Plant Molecular Biology Reporter》2018,36(3):484-490
The oomycete pathogens produce important diseases in many plant species. To identify extensin genes expressed during the oomycete Phytophthora nicotianae-Nicotiana megalosiphon interaction, we used the SuperSAGE technology. Using this approach, we detected a N. megalosiphon extensin gene (NmEXT) triggered during the interaction. The extensin gene accumulation induced by the pathogen correlated with disease resistance in different Nicotiana species. Transient expression of NmEXT gene in susceptible Nicotiana tabacum enhanced the resistance to P. nicotianae. Our date indicated that NmEXT gene served a positive role in N. tabacum resistance against P. nicotianae. 相似文献
945.
946.
Eva A. Andersson Johnny Nilsson Zhijia Ma Alf Thorstensson 《European journal of applied physiology and occupational physiology》1997,75(2):115-123
The purpose of this study was to provide objective information on the involvement of different abdominal and hip flexor muscles
during various types of common training exercises used in rehabilitation and sport. Six healthy male subjects performed altogether
38 different static and dynamic training exercises – trunk and hip flexion sit-ups, with various combinations of leg position
and support, and bi- and unilateral leg lifts. Myoelectric activity was recorded with surface electrodes from the rectus abdominis,
obliquus externus, obliquus internus, rectus femoris, and sartorius muscles and with indwelling fine-wire electrodes from
the iliacus muscle. The mean electromyogram amplitude, normalised to the highest observed value, was compared between static
and dynamic exercises separately. The hip flexors were highly activated only in exercises involving hip flexion, either lifting
the whole upper body or the legs. In contrast, the abdominal muscles showed marked activation both during trunk and hip flexion
sit-ups. In hip flexion sit-ups, flexed and supported legs increased hip flexor activation, whereas such modifications did
not generally alter the activation level of the abdominals. Bilateral, but not unilateral, leg lifts required activation of
abdominal muscles. In trunk flexion sit-ups an increased activation of the abdominal muscles was observed with increased flexion
angle, whereas the opposite was true for hip flexion sit-ups. Bilateral leg lifts resulted in higher activity levels than
hip flexion sit-ups for the iliacus and sartorius muscles, while the opposite was true for rectus femoris muscles. These data
could serve as a basis for improving the design and specificity of test and training exercises.
Accepted: 12 August 1996 相似文献
947.
John P. MacManus Ingrid Rasquinha Marsha A. Black Nicole B. Laferriere Robert Monette Teena Walker Paul Morley 《Experimental cell research》1997,233(2):310
The alkaloid protein kinase inhibitor staurosporine induced neuronal cell death with both the morphological and the biochemical characteristics of apoptosis. The punctate chromatin associated with apoptosis with retention of plasma membrane integrity was observed in neurons identified by colocalization of NeuN staining. Such cells had DNA fragmentation visualized byin situend-labeling which was seen as a laddered pattern upon gel electrophoresis. In contrast cells treated with glutamate did not exhibit either of these morphological or biochemical hallmarks of apoptosis. Instead a much smaller and more compact pyknotic structure was observed associated with smeared DNA fragmentation patterns. A confocal time-lapse study of the appearance of the morphological changes in individual nuclei after staurosporine treatment showed collapse into punctate chromatin over a period of 10 min. In contrast, the collapse into small pyknotic nuclei after glutamate treatment was at least 10 times slower. It is concluded that excitotoxicity produced by glutamate did not induce cell death by an apoptotic mechanism in cultured cortical neurons. 相似文献
948.
949.
Non-invasive measures of immunological markers are an attractive means of stress assessment in laboratory animals. Salivary IgA has been used successfully as a stress marker in the human, and several reports indicate the potential of secretory IgA as a non-invasive measure of stress in animals. The present paper describes the development of an ELISA using commercially available components for the quantification of rat IgA and validation of this assay for the quantification of rat secretory IgA in saliva and faeces. The concentration of IgA in rat saliva varied significantly between duplicate samples obtained from individual rats, and the viscosity and small total volume of rat saliva gave unsatisfactory results for IgA. Faecal IgA was present in high concentrations, and duplicate samples varied by only 2-3%. However, faecal IgA seemed less stable than IgA in other biological compartments, and this finding must be taken into consideration when using quantitative measurements of IgA as a marker of mucous humoral immune status. 相似文献
950.
Anna Andersson Omid Rasool Margit Schmidt Rimantas Kodzius Sabine Flückiger Arezou Zargari Reto Crameri Annika Scheynius 《European journal of biochemistry》2004,271(10):1885-1894
Malassezia sympodialis is an opportunistic yeast that colonizes human skin and may induce IgE and T cell reactivity in patients with atopic eczema/dermatitis syndrome (AEDS). Previously, we have cloned and expressed six recombinant allergens (rMala s 1 and rMala s 5 to rMala s 9) from this yeast. By combining high throughput screening and phage surface display techniques, 27 complete and partial IgE-binding clones of M. sympodialis have been identified. Here we enlarged the panel of recombinant M. sympodialis allergens by RACE-PCR, cloning and nucleotide sequencing to obtain the coding sequences of two new IgE-binding clones. The coding sequences of one of the clones showed similarity to the heat shock protein (HSP) family and the other to manganese superoxide dismutase (MnSOD), and both had a high degree of homology to human counterparts. The coding sequences were expressed in Escherichia coli as six-histidine tagged recombinant proteins and generated products with molecular masses of 86.1 kDa for HSP and 22.4 kDa for MnSOD. Their IgE-binding frequencies were shown to be 69% and 75%, respectively, to 28 sera from AEDS patients with serum IgE to M. sympodialis extract, indicating that HSP and MnSOD are major M. sympodialis allergens. In inhibition immunoblotting, M. sympodialis extract could inhibit the binding of serum IgE from AEDS patients to rHSP and rMnSOD in a concentration-dependent manner. The high frequency of sera from AEDS patients, showing IgE binding to both HSP and MnSOD, indicates that these allergens, designated Mala s 10 and Mala s 11, could play a role in AEDS. 相似文献