Heat-induced callose and lateral movement of assimilates from phloem

1968 ◽  
Vol 46 (10) ◽  
pp. 1215-1220 ◽  
Author(s):  
D. H. Webster ◽  
H. B. Currier
Keyword(s):  
Dark Period ◽  
Lateral Movement ◽  
Localized Heating ◽  
Sieve Tubes ◽  
Cotyledonary Petioles

Brief localized heating of cotton cotyledonary petioles increased phloem callose and decreased lateral movement of 14C-assimilates. There was little or no increase in phloem callose when plants were heated directly after a dark period of 16 or more hours. Such heated low-callose petioles had more lateral movement than heated high-callose petioles. Phloem callose and lateral movement returned to normal within 1 day after heating. These results suggest that phloem callose caused part of the decrease of lateral movement in heated high-callose petioles. Excessive phloem callose would be expected to restrict lateral movement, if movement from sieve tubes were via plasmodesmata.

Immunocytochemical studies on the behavior of RuBisCO and LHCP II during the cell cycle of synchronized Euglena gracilis

1990 ◽  
Vol 48 (3) ◽  
pp. 662-663
Author(s):  
Tetsuaki Osafune ◽  
Shuji Sumida ◽  
Tomoko Ehara ◽  
Eiji Hase ◽  
Jerome A. Schiff
Keyword(s):  
Cell Cycle ◽  
Immunoelectron Microscopy ◽  
Growth Phase ◽  
Euglena Gracilis ◽  
Dark Period ◽  
Light Period ◽  
Carboxylase Activity ◽  
Immunocytochemical Studies ◽  
Lhcp Ii

Changes in the morphology of pyrenoid and the distribution of RuBisCO in the chloroplast of Euglena gracilis were followed by immunoelectron microscopy during the cell cycle in a light (14 h)- dark (10 h) synchronized culture under photoautotrophic conditions. The imrnunoreactive proteins wereconcentrated in the pyrenoid, and less densely distributed in the stroma during the light period (growth phase, Fig. 1-2), but the pyrenoid disappeared during the dark period (division phase), and RuBisCO was dispersed throughout the stroma. Toward the end of the division phase, the pyrenoid began to form in the center of the stroma, and RuBisCO is again concentrated in that pyrenoid region. From a comparison of photosynthetic CO2-fixation with the total carboxylase activity of RuBisCO extracted from Euglena cells in the growth phase, it is suggested that the carboxylase in the pyrenoid functions in CO2-fixation in photosynthesis.

The Guatemalan Genocide Through Indigenous Mayan Literature Twenty Years After the Peace Accords: Rigoberta Menchú, Humberto Ak´Abal and Victor Montejo

2017 ◽  
Vol 7 (1) ◽  
pp. 31
Author(s):  
David Caballero Mariscal
Keyword(s):  
Social Exclusion ◽  
Dark Period ◽  
Social Situation ◽  
Point Of View ◽  
Contemporary History ◽  
Rigoberta Menchu ◽  
Testimonial Literature ◽  
History Of ◽  
Peace Accords ◽  
Historical Truth

Guatemala experienced a cruel genocide in the early eighties, in the context of a repressive Conflict. Due to the different governments´ repressive policies, this terrible social situation was little known abroad, and even in the own country. Just after the Peace Accords, several organisms worked to uncover the historical truth. In any case, we cannot forget that testimonial literature is a privileged mean to know this dark period of the contemporary history of Guatemala. This genre is particularly relevant, because the main writers are originally Mayans, and have directly suffered both repression and social exclusion due to ethnic reasons. Rigoberta Menchú, Unmberto Ak´abal and Víctor Montejo represent a new and original point of view in the measure in which they describe feelings and situations from the perspective of those who experience them personally. Testimonial literature or the Testimonio becomes an ethnographic document that allows us to know not just a period but a people who have suffered from repression and exclusion for centuries.

Investigation of Burst Pressures Prediction of Slit Aluminum Cylinders Subjected to Localized Heating

2005 ◽  
Author(s):  
C. T. Sun ◽  
T. Tanner ◽  
A. Deitemeyer ◽  
D. Nakaima ◽  
N. Bruno ◽  
...  
Keyword(s):  
Localized Heating

scholarly journals Evaluation of dsRNA delivery methods for targeting macrophage migration inhibitory factor MIF in RNAi-based aphid control

2021 ◽  
Author(s):  
Shaoshuai Liu ◽  
Maria Jose Ladera-Carmona ◽  
Minna M. Poranen ◽  
Aart J. E. van Bel ◽  
Karl-Heinz Kogel ◽  
...  
Keyword(s):  
Immune Responses ◽  
Artificial Diet ◽  
Sieve Tube ◽  
Feeding Strategies ◽  
Macrophage Migration ◽  
Delivery Methods ◽  
Host Immune Responses ◽  
Aphid Control ◽  
Barley Leaves ◽  
Sieve Tubes

AbstractMacrophage migration inhibitory factors (MIFs) are multifunctional proteins regulating major processes in mammals, including activation of innate immune responses. In invertebrates, MIF proteins participate in the modulation of host immune responses when secreted by parasitic organisms, such as aphids. In this study, we assessed the possibility to use MIF genes as targets for RNA interference (RNAi)-based control of the grain aphid Sitobion avenae (Sa) on barley (Hordeum vulgare). When nymphs were fed on artificial diet containing double-stranded (ds)RNAs (SaMIF-dsRNAs) that target sequences of the three MIF genes SaMIF1, SaMIF2 and SaMIF3, they showed higher mortality rates and these rates correlated with reduced MIF transcript levels as compared to the aphids feeding on artificial diet containing a control dsRNA (GFP-dsRNA). Comparison of different feeding strategies showed that nymphs’ survival was not altered when they fed from barley seedlings sprayed with naked SaMIF-dsRNAs, suggesting they did not effectively take up dsRNA from the sieve tubes of these plants. Furthermore, aphids’ survival was also not affected when the nymphs fed on leaves supplied with dsRNA via basal cut ends of barley leaves. Consistent with this finding, the use of sieve tube-specific YFP-labeled Arabidopsis reporter lines confirmed that fluorescent 21 nt dsRNACy3, when supplied via petioles or spraying, co-localized with xylem structures, but not with phloem tissue. Our results suggest that MIF genes are a potential target for insect control and also imply that application of naked dsRNA to plants for aphid control is inefficient. More efforts should be put into the development of effective dsRNA formulations.

Uncovering Lateral Movement using Authentication Logs

2021 ◽  
pp. 1-1
Author(s):  
Haibo Bian ◽  
Tim Bai ◽  
Mohammad A. Salahuddin ◽  
Noura Limam ◽  
Abbas Abou Daya ◽  
...  
Keyword(s):  
Lateral Movement
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