scholarly journals Skin and bones: the bacterial cytoskeleton, cell wall, and cell morphogenesis

2007 ◽  
Vol 179 (3) ◽  
pp. 381-387 ◽  
Author(s):  
Matthew T. Cabeen ◽  
Christine Jacobs-Wagner

The bacterial world is full of varying cell shapes and sizes, and individual species perpetuate a defined morphology generation after generation. We review recent findings and ideas about how bacteria use the cytoskeleton and other strategies to regulate cell growth in time and space to produce different shapes and sizes.

2011 ◽  
Vol 75 (3) ◽  
pp. 183-190 ◽  
Author(s):  
Mariusz Pietruszka ◽  
Sylwia Lewicka ◽  
Krystyna Pazurkiewicz-Kocot

The time-irreversible cell enlargement of plant cells at a constant temperature results from two independent physical processes, e.g. water absorption and cell wall yielding. In such a model cell growth starts with reduction in wall stress because of irreversible extension of the wall. The water absorption and physical expansion are spontaneous consequences of this initial modification of the cell wall (the juvenile cell vacuolate, takes up water and expands). In this model the irreversible aspect of growth arises from the extension of the cell wall. Such theory expressed quantitatively by time-dependent growth equation was elaborated by Lockhart in the 60's.The growth equation omit however a very important factor, namely the environmental temperature at which the plant cells grow. In this paper we put forward a simple phenomenological model which introduces into the growth equation the notion of temperature. Moreover, we introduce into the modified growth equation the possible influence of external growth stimulator or inhibitor (phytohormones or abiotic factors). In the presence of such external perturbations two possible theoretical solutions have been found: the linear reaction to the application of growth hormones/abiotic factors and the non-linear one. Both solutions reflect and predict two different experimental conditions, respectively (growth at constant or increasing concentration of stimulator/inhibitor). The non-linear solution reflects a common situation interesting from an environmental pollution point of view e.g. the influence of increasing (with time) concentration of toxins on plant growth. Having obtained temperature modified growth equations we can draw further qualitative and, especially, quantitative conclusions about the mechanical properties of the cell wall itself. This also concerns a new and interesting result obtained in our model: We have calculated the magnitude of the cell wall yielding coefficient (T) [m<sup>3</sup> J<sup>-1</sup>•s<sup>-1</sup>] in function of temperature which has acquired reasonable numerical value throughout.


1990 ◽  
Vol 10 (6) ◽  
pp. 3013-3019
Author(s):  
P Meaden ◽  
K Hill ◽  
J Wagner ◽  
D Slipetz ◽  
S S Sommer ◽  
...  

Yeast kre mutants define a pathway of cell wall (1----6)-beta-D-glucan synthesis, and mutants in genes KRE5 and KRE6 appear to interact early in such a pathway. We have cloned KRE5, and the sequence predicts the product to be a large, hydrophilic, secretory glycoprotein which contains the COOH-terminal endoplasmic reticulum retention signal, HDEL. Deletion of the KRE5 gene resulted in cells with aberrant morphology and extremely compromised growth. Suppressors to the KRE5 deletions arose at a frequency of 1 in 10(7) to 1 in 10(8) and permitted an analysis of deletions which were found to contain no alkali-insoluble (1----6)-beta-D-glucan. These results indicate a role for (1----6)-beta-D-glucan in normal cell growth and suggest a model for sequential assembly of (1----6)-beta-D-glucan in the yeast secretory pathway.


Development ◽  
1997 ◽  
Vol 124 (19) ◽  
pp. 3779-3786 ◽  
Author(s):  
U. Folkers ◽  
J. Berger ◽  
M. Hulskamp

Cell morphogenesis, i.e. the acquisition of a particular cell shape, can be examined genetically in the three-branched trichomes that differentiate from single epidermal cells on the leaves of Arabidopsis thaliana. In normal development, the growing trichome cell undergoes two successive branching events, resulting in a proximal side stem and a distal main stem which subsequently splits in two branches. Using new and previously described trichome mutants, we have analyzed the branching pattern in single and double mutants affecting branch number or cell size in order to determine underlying mechanisms. Our results suggest that primary branching is genetically distinct from subsequent branching events and that the latter, secondary events are initiated in response to positive and negative regulators of branching as well as subject to control by cell growth. We propose a model of how trichome cell morphogenesis is regulated during normal development.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Naser Poursarebani ◽  
Corinna Trautewig ◽  
Michael Melzer ◽  
Thomas Nussbaumer ◽  
Udda Lundqvist ◽  
...  

Abstract Grasses have varying inflorescence shapes; however, little is known about the genetic mechanisms specifying such shapes among tribes. Here, we identify the grass-specific TCP transcription factor COMPOSITUM 1 (COM1) expressing in inflorescence meristematic boundaries of different grasses. COM1 specifies branch-inhibition in barley (Triticeae) versus branch-formation in non-Triticeae grasses. Analyses of cell size, cell walls and transcripts reveal barley COM1 regulates cell growth, thereby affecting cell wall properties and signaling specifically in meristematic boundaries to establish identity of adjacent meristems. COM1 acts upstream of the boundary gene Liguleless1 and confers meristem identity partially independent of the COM2 pathway. Furthermore, COM1 is subject to purifying natural selection, thereby contributing to specification of the spike inflorescence shape. This meristem identity pathway has conceptual implications for both inflorescence evolution and molecular breeding in Triticeae.


2020 ◽  
Vol 99 (6) ◽  
pp. 2955-2966
Author(s):  
Casey N. Johnson ◽  
Mohammed M. Hashim ◽  
Christopher A. Bailey ◽  
James A. Byrd ◽  
Michael H. Kogut ◽  
...  

2010 ◽  
Vol 433 (2) ◽  
pp. e1-e2 ◽  
Author(s):  
Zachary A. Knight

More than 20 protein kinases are directly activated by 3-phosphoinositide-dependent kinase 1 (PDK1), which is a central component of the pathways that regulate cell growth, proliferation and survival. Despite the importance of PDK1 in cell signalling, highly selective PDK1 inhibitors have not been described. In this issue of the Biochemical Journal, Dario Alessi's group and their collaborators at GlaxoSmithKline report GSK2334470, a potent and selective PDK1 inhibitor. They show that this compound blocks the phosphorylation of known PDK1 substrates, but surprisingly find that the potency and kinetics of inhibition vary for different PDK1 targets. This substrate-specific inhibition has implications for the development of PDK1 inhibitors as drugs.


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