Thickened cell walls of Bacillus cereus grown in the presence of chloramphenicol: their fate during cell growth

1971 ◽  
Vol 17 (12) ◽  
pp. 1561-1565 ◽  
Author(s):  
K. L. Chung
Keyword(s):  
Cell Wall ◽  
Cell Growth ◽  
Bacillus Cereus ◽  
Cell Walls ◽  
Structural Changes ◽  
Synthetic Medium ◽  
Wall Material ◽  
Partial Removal ◽  
Daughter Cells ◽  
Thickened Wall

Bacillus cereus incubated for 4 h in a synthetic medium containing chloramphenicol was observed to form cell walls 2 to 3 times as thick as those from control cells growing in the same medium containing no antibiotic. Then the cells were washed and reincubated in fresh synthetic medium and the ultra-structural changes in the thickened walls during cell growth and elongation were examined by electron microscopy. After incubation for 20 min, multiple ruptured sites and internal fractures appeared randomly on the surface of the thickened cell wall. Large and small pieces of thickened wall fragments soon "peeled off" from the surface, leaving behind a deeper layer of wall material. Normal cell growth and elongation resumed after partial removal of the thickened cell wall. After several generations, thickened wall fragments were not observed on the surface of daughter cells.

Synchrotron infrared microspectroscopy reveals the response of Sphagnum cell wall material to its aqueous chemical environment

2018 ◽  
Vol 15 (8) ◽  
pp. 513
Author(s):  
Ewen Silvester ◽  
Annaleise R. Klein ◽  
Kerry L. Whitworth ◽  
Ljiljana Puskar ◽  
Mark J. Tobin
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Chemical Environment ◽  
Wall Material ◽  
Organic Soils ◽  
Cell Wall Material ◽  
Acid Base ◽  
Widespread Species ◽  
Flowing Liquid ◽  
Infrared Microspectroscopy

Environmental contextSphagnum moss is a widespread species in peatlands globally and responsible for a large fraction of carbon storage in these systems. We used synchrotron infrared microspectroscopy to characterise the acid-base properties of Sphagnum moss and the conditions under which calcium uptake can occur (essential for plant tissue integrity). The work allows a chemical model for Sphagnum distribution in the landscape to be proposed. AbstractSphagnum is one the major moss types responsible for the deposition of organic soils in peatland systems. The cell walls of this moss have a high proportion of carboxylated polysaccharides (polygalacturonic acids), which act as ion exchangers and are likely to be important for the structural integrity of the cell walls. We used synchrotron light source infrared microspectroscopy to characterise the acid-base and calcium complexation properties of the cell walls of Sphagnum cristatum stems, using freshly sectioned tissue confined in a flowing liquid cell with both normal water and D2O media. The Fourier transform infrared spectra of acid and base forms are consistent with those expected for protonated and deprotonated aliphatic carboxylic acids (such as uronic acids). Spectral deconvolution shows that the dominant aliphatic carboxylic groups in this material behave as a monoprotic acid (pKa=4.97–6.04). The cell wall material shows a high affinity for calcium, with a binding constant (K) in the range 103.9–104.7 (1:1 complex). The chemical complexation model developed here allows for the prediction of the chemical environment (e.g. pH, ionic content) under which Ca2+ uptake can occur, and provides an improved understanding for the observed distribution of Sphagnum in the landscape.

scholarly journals COMPOSITUM 1 contributes to the architectural simplification of barley inflorescence via meristem identity signals

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Naser Poursarebani ◽  
Corinna Trautewig ◽  
Michael Melzer ◽  
Thomas Nussbaumer ◽  
Udda Lundqvist ◽  
...  
Keyword(s):  
Cell Wall ◽  
Transcription Factor ◽  
Natural Selection ◽  
Cell Growth ◽  
Cell Walls ◽  
Molecular Breeding ◽  
Branch Formation ◽  
Genetic Mechanisms ◽  
Meristem Identity ◽  
Cell Wall Properties

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.

Étude cytochimique ultrastructurale de la dégradation des lignines dans les résidus pariétaux de bois d'épicéa et de peuplier par le Reticulitermes lucifugus var. santonensis (Rhinotermitidae, Isoptera)

1992 ◽  
Vol 70 (5) ◽  
pp. 933-941 ◽  
Author(s):  
E. Garnier-Sillam ◽  
I. Grech ◽  
Y. Czaninski ◽  
M.-T. Tollier ◽  
B. Monties
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Periodic Acid ◽  
Mechanical Action ◽  
Free Cell ◽  
Uranyl Acetate ◽  
Picea Sitchensis ◽  
Wall Material ◽  
Before And After ◽  
Acetate Lead

Free cell-wall residues were prepared by extracting wood samples of spruce (Populus euramericana cv. Fidzi Pauley) and poplar (Picea sitchensis). These species were chosen for their lignin types: guaiacyl in spruce and guaiacyl–syringyl in poplar. The parietal residues obtained were used as the sole food for the xylophagous termite Reticulitermes lucifugus var. santonensis and were compared before and after ingestion and transit in the digestive tracts. Differences due to the mechanical action of the gizzard were found in association with chemical changes. Polysaccharides were unmasked after digestion and could clearly be observed after reaction with periodic acid – thiocarbohydrazide – silver proteinate. A fibrillary meshwork was also observed inside the lignified cell walls. Biodegradation of cell wall material was particularly clear in poplar where granules formed an electron-dense plasma when uranyl acetate – lead citrate or periodic acid – thiocarbohydrazide – silver proteinate was used as a contrast medium. A selective biodegradation of syringyl monomers in poplar parietal residues was indicated by thioacidolysis but requires confirmation. Breakdown of lignified cell walls begins with a biodegradation of the lignin network associated with or followed by the digestion of polysaccharides. Syringyl-rich lignin fractions seemed to break down faster. Whether the enzymic pathway leading to ligninolysis originates from the termite digestive cells or from the endosymbionts present in their digestive tract lumen remains to be defined. Key words: Isoptera, Reticulitermes lucifugus var. santonensis, wood, lignin, spruce, poplar.

Ultrastructure des parois de cerises Bigarreau Burlat de textures différentes au cours de la maturation

1996 ◽  
Vol 74 (12) ◽  
pp. 1974-1981 ◽  
Author(s):  
C. Batisse ◽  
P. J. Coulomb ◽  
C. Coulomb ◽  
M. Buret
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Middle Lamella ◽  
Primary Cell ◽  
Wall Material ◽  
Cell Wall Degradation ◽  
Composition And Structure ◽  
Cell Wall Texture ◽  
Synthesis And Degradation ◽  
Soft Fruits

The changes in texture of fruits during ripening are linked to cell wall degradation involving synthesis and degradation of polymers. An increase in pectin solubility leads to cell sliding and an elastic aspect of tissues. The biochemical cell wall process differs between soft and crisp fruits originating from a same cultivar but cultivated under different agroclimatic conditions. Although the proportions of cell wall material are similar, the composition and structure of the two cell walls are very different at maturity. A solubilization of the middle lamella and a restructuration of the primary cell walls arising from the cells separation is observed in crisp fruits. In contrast, the middle lamella of the soft fruits is better preserved and the primary cell walls are thin and show degradation bags delimited by residual membrane formations. In addition, the macroendocytosis process by endosome individualization is more important in soft fruits. In conclusion, the fruit texture depends on the extent of the links between cell wall polymers. Keywords: cherry, cell wall, texture, ultrastructural study.

Cell growth, wall deposition, and correlated fine structure of colchicine-treated lettuce hypocotyl cells

1977 ◽  
Vol 55 (8) ◽  
pp. 902-917 ◽  
Author(s):  
L. M. Srivastava ◽  
V. K. Sawhney ◽  
M. Bonettemaker
Keyword(s):  
Cell Growth ◽  
Cell Walls ◽  
Colchicine Treatment ◽  
Dry Weight ◽  
Wall Material ◽  
Water Control ◽  
Cytological Changes ◽  
Growth Changes ◽  
Kinetics Of ◽  
Degree Of Order

The effects of colchicine, singly and in combination with gibberellic acid (GA3), on growth of lettuce hypocotyl cells are reported. After 72 h of growth, the cells in GA3 are extremely long and cylindrical, whereas those in GA3 + colchicine are very large and more or less isodiametric. The cell volume in colchicine is not significantly different from that in the water control. Kinetic data on cell growth and on dry weight of cell walls indicate a parallelism between the GA3 and GA3 + colchicine treatments and between the colchicine treatment and water control. In all treatments, certain cytological changes, viz. proliferation of dictyosomes and their vesicles, increase in endoplasmic reticulum (ER) and polyribosomes, and increased connections between the ER and plasmalemma, occur at the same time as in the water conrol and proceed ahead of evident cell growth. Changes in wall fibrils and microtubules are described. It is concluded that colchicine does not inhibit the kinetics of cell growth or the deposition of wall material, but since it causes dissolution of microtubules, the deposition of new wall fibrils is random even though it shows some degree of order, and if at that time the cells are growing rapidly under the influence of GA3, they become spherical. These results are discussed with a view to understanding the mechanisms underlying cell enlargement.

Zoospore formation in Cylindrocapsa

1975 ◽  
Vol 53 (5) ◽  
pp. 439-451 ◽  
Author(s):  
Larry R. Hoffman ◽  
Cecilia S. Hofmann
Keyword(s):  
Cell Wall ◽  
Vegetative Cell ◽  
Parental Cell ◽  
Wall Material ◽  
Cell Wall Material ◽  
Daughter Cells ◽  
Filamentous Green Algae ◽  
Zoospore Release ◽  
Zoospore Formation ◽  
Altered Cell

Quadriflagellate zoospores and conditions for their induction are described for an algal isolate tentatively identified as Cylindrocapsa geminella Wolle. Previous to this report, only biflagellate zoospores were known for Cylindrocapsa while quadriflagellate zoospores were thought to characterize the closely related Cylindrocapsopsis; this distinction is no longer valid. In our isolate, a vegetative cell may differentiate directly into a single zoospore or, more commonly, zoosporogenesis is preceded by division of a vegetative cell into two, four, or eight daughter cells, each of which becomes a zoospore. Variation in zoospore arrangement depends on the number and nature of the division sequences. Ultimately, zoospores are released from the more-or-less dissociated parental cell wall in one or more vesicles. Each primary vesicle contains one, two, four, or occasionally eight zoospores; zoospore release follows the gradual distention and dissolution of the enclosing vesicle. Light microscopic observations suggest that the zoospore-containing vesicles arise from altered cell wall material. Zoospore germlings and variations in the appearance of vegetative filaments are aiso described and attention is called to the nature of the cell wall, which is quite unlike that of most other filamentous green algae.

THE EFFECT OF PENICILLIN ON THE STRUCTURE OF STAPHYLOCOCCAL CELL WALLS

1959 ◽  
Vol 5 (6) ◽  
pp. 641-648 ◽  
Author(s):  
R. G. E. Murray ◽  
W. H. Francombe ◽  
B. H. Mayall
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Untreated Control ◽  
Osmium Tetroxide ◽  
Wall Material ◽  
Cell Wall Material ◽  
Cell Wall Synthesis ◽  
Cell Wall Component ◽  
A Cell ◽  
Resistant Strains

Cultures of sensitive stains of Staphylococcus aureus were fixed with osmium tetroxide after 1–5 hours' exposure to various does of pencillin and were embedded in methacrylate for sectioning and electron microscopy. They were compared with untreated, control cultures. The contrast of the cell wall material was untreated, control cultures. The contrast of the cell wall material was increased, by cutting the section of lanthanum nitrate.The cells increased in size and the surrounding cell wall was thinner than normal. The main lesions appeared in the developing cell wall septa, which showed a loss in density and gross irregularity of shape. Some questionable inclusions were seen in the cytoplasm. Lysis was prevented in a medium containing 0.3 M sucrose and the stable spheroplasts retained a recognizable cell wall after 24 hours' exposure to penicillin. However, the septa could not be demonstrated in the cells treated in sucrose medium.Two resistant strains were exposed to penicillin. In one, the cells showed no morphological effects; in the other, there was temporary damage to the cell septa with complete recovery.The observations support the hypothesis that penicillin interferes with the synthesis of a cell wall component and indicate that the main point of cell wall synthesis is at the site of septum formation.

Minicell formation in chloramphenicol-treated Bacillus cereus

1974 ◽  
Vol 20 (11) ◽  
pp. 1621-1623 ◽  
Author(s):  
K. L. Chung ◽  
L. P. Lin
Keyword(s):  
Cell Wall ◽  
Bacillus Cereus ◽  
Cell Separation ◽  
Synthetic Medium ◽  
Peripheral Cell ◽  
Cell Rupture ◽  
Cytological Changes

Bacillus cereus incubated in a synthetic medium containing chloramphenicol, 19 μg/ml, a concentration which is slightly below the minimal inhibitory level, was observed to form from one to several minicells through a series of cytological changes including septum initiation, invagination and completion at the subpolar region of the cell, rupture of the peripheral cell wall along the circumferential path of this region, and finally cell separation. The minicells are spherical or spheroidal in shape. A small number of heart-shaped cells was also seen.

A SEROLOGICAL STUDY OF CELL WALLS OF CERTAIN LACTIC ACID BACTERIA

1962 ◽  
Vol 8 (5) ◽  
pp. 629-637
Author(s):  
K. L. Chung ◽  
Roma Z. Hawirko
Keyword(s):  
Cell Wall ◽  
Cell Walls ◽  
Intact Cell ◽  
Synthetic Medium ◽  
Specific Cell ◽  
Intact Cells ◽  
Common Antigens ◽  
Species Specific ◽  
Relationship Of ◽  
The Relationship

From three species of Lactobacillus and three species of Streptococcus, cultured in a synthetic medium, cell walls were isolated following sonic disintegration and purified by washing. Sera against each species were prepared by injecting three rabbits with cell walls, and three with intact cells. Reciprocal agglutination tests were carried out with unabsorbed and absorbed antisera. More kinds of antibodies were detected with cell-wall antisera than with intact-cell antisera. Many species in the two genera shared common antigens. S. faecalis was the exception. Certain antigens believed to be complex haptens in nature reacted with heterologous antisera. Haemagglutination of tanned erythrocytes sensitized with a particulate cell-wall suspension showed fewer cross reactions than agglutination of intact-cell suspensions.The evidence presented shows the possibility of using antisera against species-specific cell-wall antigens for the identification of these species. The relationship of these species is discussed.

scholarly journals COMPOSITUM 1 (COM1) contributes to the architectural simplification of barley inflorescence via meristem identity signals

2020 ◽  
Author(s):  
N. Poursarebani ◽  
C. Trautewig ◽  
M. Melzer ◽  
T. Nussbaumer ◽  
U. Lundqvist ◽  
...  
Keyword(s):  
Cell Wall ◽  
Transcription Factor ◽  
Natural Selection ◽  
Cell Growth ◽  
Cell Walls ◽  
Molecular Breeding ◽  
Branch Formation ◽  
Genetic Mechanisms ◽  
Meristem Identity ◽  
Cell Wall Properties

AbstractGrasses have varying inflorescence shapes; however, little is known about the genetic mechanisms specifying such shapes among tribes. We identified the grass-specific TCP transcription factor COMPOSITUM 1 (COM1) expressed in inflorescence meristematic boundaries of different grasses. COM1 specifies branch-inhibition in Triticeae (barley) versus branch-formation in non-Triticeae grasses. Analyses of cell size, cell walls and transcripts revealed barley COM1 regulates cell growth, 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.

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