scholarly journals The function of the tapetal tissue during microsporogenesis in Lilium

2014 ◽  
Vol 50 (1-2) ◽  
pp. 83-87 ◽  
Author(s):  
S. Reznickova ◽  
M. T. Willemse
Keyword(s):  
Functional Activity ◽  
Tapetal Cell ◽  
Anther Development ◽  
Carotenoid Pigments

The main functional activity -of the tapetum in the <em>Lilium</em> anther is the synthesis of reserve lipids and carotenoid pigments. The fusion of these substances during tapetum desintegration results in the formation of pollenkitt Pollernkitt participates in the formation both of the exine and of sporopollenin-containing structures of the tapetal cell (orbicules, tapetal and peritapetal membranes) during the last steps of anther development.

scholarly journals βVPE is involved in tapetal degradation and pollen development by activating proprotease maturation in Arabidopsis thaliana

2019 ◽  
Vol 71 (6) ◽  
pp. 1943-1955 ◽  
Author(s):  
Ziyi Cheng ◽  
Xiaorui Guo ◽  
Jiaxue Zhang ◽  
Yadi Liu ◽  
Bing Wang ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pollen Development ◽  
Tapetal Cell ◽  
Cysteine Proteases ◽  
Anther Development ◽  
Mature Protein ◽  
Processing Enzyme ◽  
Mature Enzyme ◽  
Mature Protease

Abstract Vacuolar processing enzyme (VPE) is responsible for the maturation and activation of vacuolar proteins in plants. We found that βVPE was involved in tapetal degradation and pollen development by transforming proproteases into mature protease in Arabidopsis thaliana. βVPE was expressed specifically in the tapetum from stages 5 to 8 of anther development. The βVPE protein first appeared as a proenzyme and was transformed into the mature enzyme before stages 7–8. The recombinant βVPE protein self-cleaved and transformed into a 27 kDa mature protein at pH 5.2. The mature βVPE protein could induce the maturation of CEP1 in vitro. βvpe mutants exhibited delayed vacuolar degradation and decreased pollen fertility. The maturation of CEP1, RD19A, and RD19C was seriously inhibited in βvpe mutants. Our results indicate that βVPE is a crucial processing enzyme that directly participates in the maturation of cysteine proteases before vacuolar degradation, and is indirectly involved in pollen development and tapetal cell degradation.

meiotin-1 gene expression in normal anthers and in anthers exhibiting prematurely condensed chromosomes

Genome ◽  
2000 ◽  
Vol 43 (4) ◽  
pp. 604-612 ◽  
Author(s):  
C A Hasenkampf ◽  
A A Taylor ◽  
N U Siddiqui ◽  
C D Riggs
Keyword(s):  
Gene Expression ◽  
Tapetal Cell ◽  
Chromatin Condensation ◽  
Anther Development ◽  
Normal Cells ◽  
Vegetative Tissues ◽  
Tapetal Cells ◽  
Low Levels ◽  
Temporal And Spatial ◽  
Transcriptional Induction

We have cloned and sequenced the promoter of a meiotin-1 gene, and have determined the precise temporal and spatial pattern of meiotin-1 gene expression. The expression of the meiotin-1 gene is controlled in two increments. The meiotin-1 gene is not expressed in any of the vegetative tissues examined. Early in microsporogenesis, low levels of meiotin-1 RNA can be detected. At the onset of meiosis, there is a dramatic increase in meiotin-1 RNA levels in both tapetal and meiotic cells. However, while meiotin-1 RNA is observed in both the nucleus and cytoplasm of meiotic cells, it is found only in the nucleus of the tapetal cells. We have also examined the expression of the meiotin-1 gene in aberrant meiotic nuclei that prematurely condense their chromosomes; these nuclei have reduced levels of the meiotin-1 protein. The aberrant nuclei have only the basal level of meiotin-1 RNA; they do not exhibit the transcriptional induction seen for normal cells at the onset of meiosis. Implications for the function of meiotin-1 in regulating chromatin condensation, and in coordinating meiotic and tapetal cell activities are discussed.Key words: anther development, chromatin, meiosis, meiotin-1, promoter.

scholarly journals PRX9 and PRX40 are extensin peroxidases essential for maintaining tapetum and microspore cell wall integrity during Arabidopsis anther development

2018 ◽  
Author(s):  
Joseph R. Jacobowitz ◽  
Jing-Ke Weng
Keyword(s):  
Cell Wall ◽  
Pollen Development ◽  
Tapetal Cell ◽  
Pollen Grains ◽  
Anther Development ◽  
Cell Wall Integrity ◽  
Class Iii ◽  
Male Sterile ◽  
Male Gametes ◽  
Encoding Genes

AbstractPollen and microspore development is an essential step in the life cycle of all land plants that generate male gametes. Within flowering plants, pollen development occurs inside of the anther. Here, we report the identification of two class III peroxidase-encoding genes, PRX9 and PRX40, that are genetically redundant and essential for proper anther and pollen development in Arabidopsis thaliana. Arabidopsis double mutants devoid of functional PRX9 and PRX40 are male-sterile. The mutant anthers display swollen, hypertrophic tapetal cells and pollen grains, suggesting disrupted cell wall integrity. These phenotypes ultimately lead to nearly 100%-penetrant pollen degeneration upon anther maturation. Using immunochemical and biochemical approaches, we show that PRX9 and PRX40 are likely extensin peroxidases that contribute to the establishment of tapetal cell wall integrity during anther development. This work identifies PRX9 and PRX40 as the first extensin peroxidases to be described in Arabidopsis and highlights the importance of extensin cross-linking during plant development.

scholarly journals βVPE is involved in tapetal degradation and pollen development by activating proprotease maturation in Arabidopsis thaliana

2018 ◽  
Author(s):  
Ziyi Cheng ◽  
Bin Yin ◽  
Jiaxue Zhang ◽  
Yadi Liu ◽  
Bing Wang ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Pollen Development ◽  
Tapetal Cell ◽  
Cysteine Proteases ◽  
Anther Development ◽  
Mature Protein ◽  
Processing Enzyme ◽  
Mature Enzyme ◽  
Mature Protease

Vacuolar processing enzyme (VPE) is responsible for the maturation and activation of vacuolar proteins in plants. We found that βVPE was involved in tapetal degradation and pollen development by transforming proproteases into mature protease in Arabidopsis thaliana. βVPE was expressed specifically in the tapetum from stages 5–8 of anther development. The βVPE protein first appeared as a proenzyme and transformed into the mature enzyme before stages 7–8. The recombinant βVPE protein self-cleaved and transformed to a 27-kD mature protein at pH 5.2. The mature βVPE protein could induce the maturation of CEP1 in vitro. βvpe mutants exhibited delayed vacuolar degradation and decreased pollen fertility. The maturation of CEP1, RD19A, and RD19C were seriously inhibited in βvpe mutants. Our results indicate that βVPE is a crucial processing enzyme that directly participates in the maturation of cysteine proteases before vacuolar degradation, and is indirectly involved in pollen development and tapetal cell degradation.

Representing utility and deploying the body

2020 ◽  
Vol 43 ◽  
Author(s):  
David Spurrett
Keyword(s):  
Functional Activity ◽  
Degrees Of Freedom ◽  
The Body ◽  
Target Article ◽  
Processing Demands ◽  
The Many

Abstract Comprehensive accounts of resource-rational attempts to maximise utility shouldn't ignore the demands of constructing utility representations. This can be onerous when, as in humans, there are many rewarding modalities. Another thing best not ignored is the processing demands of making functional activity out of the many degrees of freedom of a body. The target article is almost silent on both.

Changes in polyamine synthesis during anther development and pollen germination in tobacco (Nicotiana tabacum)

1994 ◽  
Vol 92 (1) ◽  
pp. 61-68 ◽  
Author(s):  
Fatiha Chibi ◽  
Angel Jesus Matilla ◽  
Trinidad Angosto ◽  
Dolores Garrido
Keyword(s):  
Nicotiana Tabacum ◽  
Pollen Germination ◽  
Anther Development ◽  
Polyamine Synthesis

Plasma Derived von Willebrand Factor Preparations: Collagen Binding and Ristocetin Cofactor Activities

1997 ◽  
Vol 78 (02) ◽  
pp. 930-933 ◽  
Author(s):  
Ping Chang ◽  
D L Aronson
Keyword(s):  
Von Willebrand Factor ◽  
Functional Activity ◽  
Binding Activity ◽  
Collagen Binding ◽  
Binding Function ◽  
Cofactor Activity ◽  
Von Willebrand ◽  
Willebrand Factor ◽  
Ristocetin Cofactor ◽  
Ristocetin Cofactor Activity

SummaryFive plasma preparations (11 lots) used in the treatment of von Willebrand’s disease (vWD) were evaluated. The collagen binding function of von Willebrand factor (vWF) containing preparations was compared with the ristocetin cofactor activity and the vWF antigen. Some preparations have higher ratio of functional activity (ristocetin cofactor and collagen binding) relative to the antigen than is found in normal plasma. The ristocetin cofactor activity and the collagen binding activity are tightly correlated (r = .95). Ultracentrifugal (UCF) analysis was used to compare the size distribution of vWf antigen, ristocetin cofactor and collagen binding activity. The sedimentation of all of the vWF parameters in the plasma products was slower than in plasma. In plasma products the ristocetin cofactor activity sediments the most rapidly, the collagen binding activity is slower and the antigen the slowest. The collagen/antigen ratio decreases with decreasing vWF size. Assignment of potency to vWF containing preparations utilizing the collagen binding activity may be more precise and as accurate as with the traditional ristocetin cofactor assay.

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