[Feedback control mechanisms of plant cell expansion]. Progress report, [June 1989--June 1992]

ABSTRACT A new method for the investigation of hypothalamo-pituitary-gonadal and adrenal feedback control mechanisms based on the biological neutralization of gonadal and adrenal steroids by active immunization is proposed. The regulatory influence of a given steroid in the feedback control is proved when reduction of the free, biologically active fraction of this steroid caused by antibody binding induces a positive response of the pituitary, thus effecting gonadal or adrenal hypertrophy and hyperfunction. The advantages and limitations of the new model are demonstrated by the effects of active immunization of rabbits with cortisol (F), aldosterone (Aldo), dehydroepiandrosterone (DHA), androstenedione (Δ4-A), testosterone (T), 5α-dihydrotestosterone (5α-DHT), 5β-DHT and oestradiol (E2). In the immunized animals and in a control group serum concentrations of total corticosteroids (TC), DHA, T, Δ4-A, E1, E2, LH and FSH, the percentage of binding of steroids in serum and the specificity of the antisera are determined. The testes are evaluated by histometry and the nuclear volume of the adrenocortical and Leydig cells is measured.

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A novel, cellulose synthesis inhibitory action of ancymidol impairs plant cell expansion

Journal of Experimental Botany ◽

10.1093/jxb/ern250 ◽

2008 ◽

Vol 59 (14) ◽

pp. 3963-3974 ◽

Cited By ~ 16

Author(s):

J. Hofmannova ◽

K. Schwarzerova ◽

L. Havelkova ◽

P. Borikova ◽

J. Petrasek ◽

...

Keyword(s):

Plant Cell ◽

Cell Expansion ◽

Inhibitory Action ◽

Cellulose Synthesis

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Ca2+ Signaling in the Inner Ear

Physiology ◽

10.1152/physiol.00040.2006 ◽

2007 ◽

Vol 22 (2) ◽

pp. 131-144 ◽

Cited By ~ 33

Author(s):

Fabio Mammano ◽

Mario Bortolozzi ◽

Saida Ortolano ◽

Fabio Anselmi

Keyword(s):

Feedback Control ◽

Inner Ear ◽

Control Mechanisms ◽

Sensory Receptors ◽

Key Players ◽

Mechanical Disturbances

The inner ear contains delicate sensory receptors that have adapted to detect the minutest mechanical disturbances. Ca2+ ions are implicated in all steps of the transduction process, as well as in its regulation by an impressive ensemble of finely tuned feedback control mechanisms. Recent studies have unveiled some of the key players, but things do not sound quite right yet.

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Handedness in plant cell expansion: a mutant perspective on helical growth

New Phytologist ◽

10.1111/nph.16034 ◽

2019 ◽

Vol 225 (1) ◽

pp. 53-69 ◽

Cited By ~ 5

Author(s):

Henrik Buschmann ◽

Agnes Borchers

Keyword(s):

Plant Cell ◽

Cell Expansion ◽

Helical Growth

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The Role of Brachypodium distachyon Wall-Associated Kinases (WAKs) in Cell Expansion and Stress Responses

Cells ◽

10.3390/cells9112478 ◽

2020 ◽

Vol 9 (11) ◽

pp. 2478

Author(s):

Xingwen Wu ◽

Antony Bacic ◽

Kim L. Johnson ◽

John Humphries

Keyword(s):

Cell Wall ◽

Stress Response ◽

Plant Cell ◽

Stress Responses ◽

Cell Expansion ◽

Plant Cell Wall ◽

Brachypodium Distachyon ◽

Critical Role ◽

Cell Integrity

The plant cell wall plays a critical role in signaling responses to environmental and developmental cues, acting as both the sensing interface and regulator of plant cell integrity. Wall-associated kinases (WAKs) are plant receptor-like kinases located at the wall—plasma membrane—cytoplasmic interface and implicated in cell wall integrity sensing. WAKs in Arabidopsis thaliana have been shown to bind pectins in different forms under various conditions, such as oligogalacturonides (OG)s in stress response, and native pectin during cell expansion. The mechanism(s) WAKs use for sensing in grasses, which contain relatively low amounts of pectin, remains unclear. WAK genes from the model monocot plant, Brachypodium distachyon were identified. Expression profiling during early seedling development and in response to sodium salicylate and salt treatment was undertaken to identify WAKs involved in cell expansion and response to external stimuli. The BdWAK2 gene displayed increased expression during cell expansion and stress response, in addition to playing a potential role in the hypersensitive response. In vitro binding assays with various forms of commercial polysaccharides (pectins, xylans, and mixed-linkage glucans) and wall-extracted fractions (pectic/hemicellulosic/cellulosic) from both Arabidopsis and Brachypodium leaf tissues provided new insights into the binding properties of BdWAK2 and other candidate BdWAKs in grasses. The BdWAKs displayed a specificity for the acidic pectins with similar binding characteristics to the AtWAKs.

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