AUTORADIOGRAPHIC STUDIES OF BACTERIAL CELL WALL REPLICATION: I. CELL WALL GROWTH OF BACILLUS CEREUS IN THE PRESENCE OF CHLORAMPHENICOL

1967 ◽  
Vol 13 (4) ◽  
pp. 341-350 ◽  
Author(s):  
K. L. Chung
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Bacillus Cereus ◽  
First Generation ◽  
Third Generation ◽  
Cell Wall Synthesis ◽  
Daughter Cells ◽  
Entire Cell ◽  
Wall Growth ◽  
The Difference

The pattern of cell wall synthesis as measured by the incorporation of tritiated alanine into the cell wall of Bacillus cereus, and the number of synthesizing sites in the cell wall were studied by the direct and the reverse autoradiographic labelling methods.In the absence of chloramphenicol, the new cell wall was initiated at two or three segments, and later increased to four or five segments which continued to elongate but not to increase in number until the bacilli had made preparation for cell division. Shortly before the centripetal growth of the cell wall and constriction to separate daughter cells, two to three more new wall-segments were added to those already present. The second and third generation cells retained some old wall-segments from the first-generation mother, which remained as discrete clusters of grains, and could easily be distinguished from the new segments.In the presence of chloramphenicol, the new wall was initiated at 8 to 10 sites. Further incubation resulted in the uniform incorporation of labels at multiple sites along the entire cell length.The patterns of new wall replication as studied by the two methods were compared. To account for the difference in synthesizing sites when chloramphenicol is present, it is suggested that the cells have either used the maximum number of sites or have completely bypassed all the sites and allowed the tritiated alanine to diffuse into the wall to become incorporated.

CELL WALL REPLICATION: I. CELL WALL GROWTH OF BACILLUS CEREUS AND BACILLUS MEGATERIUM

1964 ◽  
Vol 10 (1) ◽  
pp. 43-48 ◽  
Author(s):  
K. L. Chung ◽  
R. Z. Hawirko ◽  
P. K. Isaac
Keyword(s):  
Cell Wall ◽  
Bacillus Cereus ◽  
Bacillus Megaterium ◽  
Central Area ◽  
Cell Length ◽  
Cell Wall Growth ◽  
Daughter Cells ◽  
Wall Growth

Cell wall replication of Bacillus cereus and Bacillus megaterium was studied by differential labelling with fluorescent and non-fluorescent antibody.Growth of new cell wall in B. cereus was initiated near the poles. In the old wall, additional new wall segments gradually developed to form an alternating pattern of new and old wall segments. Further growth elongated the new wall and pushed the old segments apart. Separation of daughter cells appeared to involve splitting of the transverse septa laid down at or near the old wall segments.Growth of new cell wall of B. megaterium was initiated either at one of the poles or at the central area of the cell. Multiple segments of new and old wall appeared along the cell length. Further elongation was followed by formation of transverse septa and separation of daughter cells incorporating either old or new wall segments.Our evidence clearly shows that growth and elongation of the two bacilli do not occur by diffuse intercalation of new cell wall into the old.

scholarly journals Generation of asymmetry during development. Segregation of type-specific proteins in Caulobacter.

1979 ◽  
Vol 81 (1) ◽  
pp. 123-136 ◽  
Author(s):  
N Agabian ◽  
M Evinger ◽  
G Parker
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Messenger Rna ◽  
Cell Types ◽  
Specific Protein ◽  
Soluble Proteins ◽  
Specific Cell ◽  
Daughter Cells ◽  
Specific Proteins ◽  
Entire Cell

An essential event in developmental processes is the introduction of asymmetry into an otherwise undifferentiated cell population. Cell division in Caulobacter is asymmetric; the progeny cells are structurally different and follow different sequences of development, thus providing a useful model system for the study of differentiation. Because the progeny cells are different from one another, there must be a segregation of morphogenetic and informational components at some time in the cell cycle. We have examined the pattern of specific protein segregation between Caulobacter stalked and swarmer daughter cells, with the rationale that such a progeny analysis would identify both structurally and developmentally important proteins. To complement the study, we have also examined the pattern of protein synthesis during synchronous growth and in various cellular fractions. We show here, for the first time, that the association of proteins with a specific cell type may result not only from their periodicity of synthesis, but also from their pattern of distribution at the time of cell division. Several membrane-associated and soluble proteins are segregated asymmetrically between progeny stalked and swarmer cells. The data further show that a subclass of soluble proteins becomes associated with the membrane of the progeny stalked cells. Therefore, although the principal differentiated cell types possess different synthetic capabilities and characteristic proteins, the asymmetry between progeny stalked and swarmer cells is generated primarily by the preferential association of specific soluble proteins with the membrane of only one daughter cell. The majority of the proteins which exhibit this segregation behavior are synthesized during the entire cell cycle and exhibit relatively long, functional messenger RNA half-lives.

scholarly journals Bacteriophage SP01 Gene Product 56 Inhibits Bacillus subtilis Cell Division by Interacting with FtsL and Disrupting Pbp2B and FtsW Recruitment

2020 ◽  
Vol 203 (2) ◽  
pp. e00463-20
Author(s):  
Amit Bhambhani ◽  
Isabella Iadicicco ◽  
Jules Lee ◽  
Syed Ahmed ◽  
Max Belfatto ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Cell Division ◽  
Gene Product ◽  
Fluorescent Protein ◽  
Lytic Bacteriophage ◽  
Cell Wall Synthesis ◽  
Content Type ◽  
Ftsz Ring ◽  
Green Fluorescent

ABSTRACTPrevious work identified gene product 56 (gp56), encoded by the lytic bacteriophage SP01, as being responsible for inhibition of Bacillus subtilis cell division during its infection. Assembly of the essential tubulin-like protein FtsZ into a ring-shaped structure at the nascent site of cytokinesis determines the timing and position of division in most bacteria. This FtsZ ring serves as a scaffold for recruitment of other proteins into a mature division-competent structure permitting membrane constriction and septal cell wall synthesis. Here, we show that expression of the predicted 9.3-kDa gp56 of SP01 inhibits later stages of B. subtilis cell division without altering FtsZ ring assembly. Green fluorescent protein-tagged gp56 localizes to the membrane at the site of division. While its localization does not interfere with recruitment of early division proteins, gp56 interferes with the recruitment of late division proteins, including Pbp2b and FtsW. Imaging of cells with specific division components deleted or depleted and two-hybrid analyses suggest that gp56 localization and activity depend on its interaction with FtsL. Together, these data support a model in which gp56 interacts with a central part of the division machinery to disrupt late recruitment of the division proteins involved in septal cell wall synthesis.IMPORTANCE Studies over the past decades have identified bacteriophage-encoded factors that interfere with host cell shape or cytokinesis during viral infection. The phage factors causing cell filamentation that have been investigated to date all act by targeting FtsZ, the conserved prokaryotic tubulin homolog that composes the cytokinetic ring in most bacteria and some groups of archaea. However, the mechanisms of several phage factors that inhibit cytokinesis, including gp56 of bacteriophage SP01 of Bacillus subtilis, remain unexplored. Here, we show that, unlike other published examples of phage inhibition of cytokinesis, gp56 blocks B. subtilis cell division without targeting FtsZ. Rather, it utilizes the assembled FtsZ cytokinetic ring to localize to the division machinery and to block recruitment of proteins needed for septal cell wall synthesis.

scholarly journals The Antituberculosis Drug Ethambutol Selectively Blocks Apical Growth in CMN Group Bacteria

mBio ◽  
2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Karin Schubert ◽  
Boris Sieger ◽  
Fabian Meyer ◽  
Giacomo Giacomelli ◽  
Kati Böhm ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Cell Growth ◽  
Antibiotic Treatment ◽  
Bacterial Infections ◽  
Apical Cell ◽  
Combined Treatment ◽  
Mycolic Acid ◽  
Cell Wall Synthesis ◽  
Beta Lactam

ABSTRACT Members of the genus Mycobacterium are the most prevalent cause of infectious diseases. Mycobacteria have a complex cell envelope containing a peptidoglycan layer and an additional arabinogalactan polymer to which a mycolic acid bilayer is linked; this complex, multilayered cell wall composition (mAGP) is conserved among all CMN group bacteria. The arabinogalactan and mycolic acid synthesis pathways constitute effective drug targets for tuberculosis treatment. Ethambutol (EMB), a classical antituberculosis drug, inhibits the synthesis of the arabinose polymer. Although EMB acts bacteriostatically, its underlying molecular mechanism remains unclear. Here, we used Corynebacterium glutamicum and Mycobacterium phlei as model organisms to study the effects of EMB at the single-cell level. Our results demonstrate that EMB specifically blocks apical cell wall synthesis, but not cell division, explaining the bacteriostatic effect of EMB. Furthermore, the data suggest that members of the family Corynebacterineae have two dedicated machineries for cell elongation (elongasome) and cytokinesis (divisome). IMPORTANCE Antibiotic treatment of bacterial pathogens has contributed enormously to the increase in human health. Despite the apparent importance of antibiotic treatment of bacterial infections, surprisingly little is known about the molecular functions of antibiotic actions in the bacterial cell. Here, we analyzed the molecular effects of ethambutol, a first-line antibiotic against infections caused by members of the genus Mycobacterium. We find that this drug selectively blocks apical cell growth but still allows for effective cytokinesis. As a consequence, cells survive ethambutol treatment and adopt a pneumococcal cell growth mode with cell wall synthesis only at the site of cell division. However, combined treatment of ethambutol and beta-lactam antibiotics acts synergistically and effectively stops cell proliferation. IMPORTANCE Antibiotic treatment of bacterial pathogens has contributed enormously to the increase in human health. Despite the apparent importance of antibiotic treatment of bacterial infections, surprisingly little is known about the molecular functions of antibiotic actions in the bacterial cell. Here, we analyzed the molecular effects of ethambutol, a first-line antibiotic against infections caused by members of the genus Mycobacterium. We find that this drug selectively blocks apical cell growth but still allows for effective cytokinesis. As a consequence, cells survive ethambutol treatment and adopt a pneumococcal cell growth mode with cell wall synthesis only at the site of cell division. However, combined treatment of ethambutol and beta-lactam antibiotics acts synergistically and effectively stops cell proliferation.

Effects of Copaifera duckei Dwyer oleoresin on the cell wall and cell division of Bacillus cereus

2013 ◽  
Vol 62 (7) ◽  
pp. 1032-1037 ◽  
Author(s):  
Elizabeth Cristina Gomes dos Santos ◽  
Claudio Luis Donnici ◽  
Elizabeth Ribeiro da Silva Camargos ◽  
Adriana Augusto de Rezende ◽  
Eloisa Helena de Aguiar Andrade ◽  
...  
Keyword(s):  
Cell Wall ◽  
Antibacterial Activity ◽  
Cell Division ◽  
Bacillus Cereus ◽  
Mechanism Of Action ◽  
Gram Negative Bacteria ◽  
Bactericidal Action ◽  
Transmission Electron ◽  
Sds Page ◽  
Division Process

The aim of this work was to evaluate the antibacterial activity of Copaifera duckei oleoresin and to determine its possible mechanism of action against bacteria of clinical and food interest. The antibacterial activity was determined by agar diffusion and dilution methods; the mechanism of action by transmission electron microscopy and by SDS-PAGE; the bioactive compounds by bioautography; and the chemical analysis by GC/MS. Oleoresin showed activity against nine of the 11 strains of bacteria tested. Bacillus cereus was the most sensitive, with a MIC corresponding to 0.03125 mg ml−1 and with a bactericidal action. Oleoresin acted on the bacterial cell wall, removing proteins and the S-layer, and interfering with the cell-division process. This activity probably can be attributed to the action of terpenic compounds, among them the bisabolene compound. Gram-negative bacteria tested were not inhibited. C. duckei oleoresin is a potential antibacterial, suggesting that this oil could be used as a therapeutic alternative, mainly against B. cereus.

Cell Volume and the Control of the Chlamydomonas Cell Cycle

1982 ◽  
Vol 54 (1) ◽  
pp. 173-191 ◽  
Author(s):  
R. A. CRAIGIE ◽  
T. CAVALIER-SMITH
Keyword(s):  
Cell Cycle ◽  
Cell Wall ◽  
Cell Division ◽  
Simple Model ◽  
Cell Volume ◽  
Mother Cell ◽  
Dark Period ◽  
Size Fractions ◽  
Daughter Cells ◽  
Mother Cell Wall

Chlamydomonas reinhardii divides by multiple fission to produce 2n daughter cells per division burst, where n is an integer. By separating predivision cells from synchronous cultures into fractions of differing mean cell volumes, and electronically measuring the numbers and volume distributions of the daughter cells produced by the subsequent division burst, we have shown that n is determined by the volume of the parent cell. Control of n can occur simply, if after every cell division the daughter cells monitor their volume and divide again if, and only if, their volume is greater than a fixed minimum value. In cultures synchronized by 12-h light/12-h dark cycles, the larger parent cells divide earlier in the dark period than do smaller cells. This has been shown by two independent methods: (1) by separating cells into different size fractions by Percoll density-gradient centrifugation and using the light microscope to see when they divide; and (2) by studying changes in the cell volume distribution of unfractioned cultures. Since daughter cells remain within the mother-cell wall for some hours after cell division, and cell division causes an overall swelling of the mother-cell wall, the timing of division can be determined electronically by measuring this increase in cell volume that occurs in the dark period in the absence of growth; we find that cells at the large end of the size distribution range undergo this swelling first, and are then followed by successively smaller size fractions. A simple model embodying a sizer followed by a timer gives a good quantitative fit to these data for 12-h light/12-h dark cycles if cell division occurs 12-h after attaining a critical volume of approximately 140 μm3. However, this simple model is called into question by our finding that alterations in the length of the light period alter the rate of progress towards division even of cells that have attained their critical volume. We discuss the relative roles of light and cell volume in the control of division timing in the Chlamydomonas cell cycle.

scholarly journals The heat-shock response of Listeria monocytogenes comprises genes involved in heat shock, cell division, cell wall synthesis, and the SOS response

Microbiology ◽  
2007 ◽  
Vol 153 (10) ◽  
pp. 3593-3607 ◽  
Author(s):  
Stijn van der Veen ◽  
Torsten Hain ◽  
Jeroen A. Wouters ◽  
Hamid Hossain ◽  
Willem M. de Vos ◽  
...  
Keyword(s):  
Cell Wall ◽  
Cell Division ◽  
Listeria Monocytogenes ◽  
Heat Shock ◽  
Heat Shock Response ◽  
Sos Response ◽  
Cell Wall Synthesis ◽  
Shock Cell ◽  
Shock Response ◽  
Division Cell

scholarly journals DivIVA Is Required for Polar Growth in the MreB-Lacking Rod-Shaped Actinomycete Corynebacterium glutamicum

2008 ◽  
Vol 190 (9) ◽  
pp. 3283-3292 ◽  
Author(s):  
Michal Letek ◽  
Efrén Ordóñez ◽  
José Vaquera ◽  
William Margolin ◽  
Klas Flärdh ◽  
...  
Keyword(s):  
Cell Wall ◽  
Bacillus Subtilis ◽  
Cell Division ◽  
Streptococcus Pneumoniae ◽  
Corynebacterium Glutamicum ◽  
Chromosome Segregation ◽  
Polar Growth ◽  
Cell Wall Synthesis ◽  
Peptidoglycan Synthesis ◽  
Polarized Cell Growth

ABSTRACT The actinomycete Corynebacterium glutamicum grows as rod-shaped cells by zonal peptidoglycan synthesis at the cell poles. In this bacterium, experimental depletion of the polar DivIVA protein (DivIVACg) resulted in the inhibition of polar growth; consequently, these cells exhibited a coccoid morphology. This result demonstrated that DivIVA is required for cell elongation and the acquisition of a rod shape. DivIVA from Streptomyces or Mycobacterium localized to the cell poles of DivIVACg-depleted C. glutamicum and restored polar peptidoglycan synthesis, in contrast to DivIVA proteins from Bacillus subtilis or Streptococcus pneumoniae, which localized at the septum of C. glutamicum. This confirmed that DivIVAs from actinomycetes are involved in polarized cell growth. DivIVACg localized at the septum after cell wall synthesis had started and the nucleoids had already segregated, suggesting that in C. glutamicum DivIVA is not involved in cell division or chromosome segregation.

scholarly journals A conserved subcomplex within the bacterial cytokinetic ring activates cell wall synthesis by the FtsW-FtsI synthase

2020 ◽  
Vol 117 (38) ◽  
pp. 23879-23885 ◽  
Author(s):  
Lindsey S. Marmont ◽  
Thomas G. Bernhardt
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Cell Wall ◽  
Cell Division ◽  
Polymerase Activity ◽  
Bacterial Cell Division ◽  
Cell Wall Synthesis ◽  
Negative Regulators ◽  
Major Function ◽  
Osmotic Lysis ◽  
Direct Activator

Cell division in bacteria is mediated by a multiprotein assembly called the divisome. A major function of this machinery is the synthesis of the peptidoglycan (PG) cell wall that caps the daughter poles and prevents osmotic lysis of the newborn cells. Recent studies have implicated a complex of FtsW and FtsI (FtsWI) as the essential PG synthase within the divisome; however, how PG polymerization by this synthase is regulated and coordinated with other activities within the machinery is not well understood. Previous results have implicated a conserved subcomplex of division proteins composed of FtsQ, FtsL, and FtsB (FtsQLB) in the regulation of FtsWI, but whether these proteins act directly as positive or negative regulators of the synthase has been unclear. To address this question, we purified a five-memberPseudomonas aeruginosadivision complex consisting of FtsQLB-FtsWI. The PG polymerase activity of this complex was found to be greatly stimulated relative to FtsWI alone. Purification of complexes lacking individual components indicated that FtsL and FtsB are sufficient for FtsW activation. Furthermore, support for this activity being important for the cellular function of FtsQLB was provided by the identification of two division-defective variants of FtsL that still form normal FtsQLB-FtsWI complexes but fail to activate PG synthesis. Thus, our results indicate that the conserved FtsQLB complex is a direct activator of PG polymerization by the FtsWI synthase and thereby define an essential regulatory step in the process of bacterial cell division.

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