Molecular structure of the resistant biopolymer in zygospore cell walls of Chlamydomonas monoica

A glance at previous Leeuwenhoek Lectures reveals that in a number of cases the Lecturer has felt obliged to preface his account with an apology to the effect that the subject of his lecture would seem to bear little relationship to the distinguished work of Antony van Leeuwenhoek. In my case, however, such apology is unnecessary as a reasonably direct connexion can be established between those remarkable observations in the seventeenth century and the work described here. Leeuwenhoek’s description of bacteria is based on their appearance under his primitive but remarkably effective microscopes. Such appearance is, of course, governed by shape and we see from the published record that cocci, bacilli and spirochaetes were observed and accurately described in terms of size and shape. These features are functions of the nature and rigidity of the wall surrounding the organisms and so are related to molecular structure; the purpose of my lecture is to describe certain aspects of the recently acquired knowledge of the molecular architecture of bacterial cell walls. The great interest that has developed in the chemistry and biochemistry of bacterial cell walls during the last ten years or so has arisen for a number of reasons (cf. Salton 1964). In the first place, walls are of interest because they represent a substantial proportion of the metabolic products of the cell; they frequently comprise up to 20% of the dry weight of cells and so must be regarded as important metabolites. Moreover, their chemical structure is interesting in view of their physical properties. Thus, besides being reasonably rigid structures with considerable strength they are nevertheless freely permeable towards cellular products and nutrients. Under certain conditions even large molecules such as antibodies, extracellular enzymes and nucleic acids can penetrate the wall, although the full extent and nature of this permeability, and the effect of negatively charged polymers (e. g. teichoic acids) in the wall, has not been clearly defined. The wall is frequently the site of important antigenic material; for example, in many cases it has been shown, that group- or type-specific antigens are located in the outer structures of the cell, including the wall. Consequently, a better understanding of the immunological properties of bacteria, and particularly such features as patho-genicity, require a full understanding of the structure, function and biosynthesis of wall components.

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Raman microscopic analysis of wood after treatment with the ionic liquid, 1-ethyl-3-methylimidazolium chloride

Holzforschung ◽

10.1515/hf-2014-0060 ◽

2015 ◽

Vol 69 (3) ◽

pp. 273-279 ◽

Cited By ~ 13

Author(s):

Toru Kanbayashi ◽

Hisashi Miyafuji

Keyword(s):

Molecular Structure ◽

Cell Wall ◽

Ionic Liquid ◽

Raman Spectra ◽

Cell Walls ◽

Cryptomeria Japonica ◽

Microscopic Analysis ◽

Japanese Cedar ◽

Wall Structure ◽

Chemical Components

Abstract Japanese cedar (Cryptomeria japonica) was treated with the ionic liquid (IL) 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]), which is a solvent for cellulose, and the changes in the chemical components and their distribution in wood cell walls have been investigated by Raman microscopy. Raman spectra, recorded from various areas of the cell walls, showed that lignin in the compound middle lamellae (CML) and cell corners (CC) was resistant to the reaction with [C2mim][Cl], but its molecular structure changed partially. The reactivity of cellulose and hemicelluloses with [C2mim][Cl] was higher than that of lignin in the cell wall, and the cell wall structure was maintained even in an advanced state of the reactions. The effects of [C2mim]-[Cl] on cellulose and hemicelluloses in the cell wall were homogeneous, whereas that of lignin was inhomogeneous.

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Ectodesmata as Revealed By Freeze-Etch Preparations of Plant Epidermal Cell Walls

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100072782 ◽

1973 ◽

Vol 31 ◽

pp. 468-469

Author(s):

N.C. Lyon ◽

W. C. Mueller

Keyword(s):

Electron Microscopy ◽

Acetic Acid ◽

Nitric Acid ◽

Oxalic Acid ◽

Light Microscopy ◽

Epidermal Cell ◽

Cell Walls ◽

Plant Viruses ◽

Plant Leaves ◽

Thin Sections

Schumacher and Halbsguth first demonstrated ectodesmata as pores or channels in the epidermal cell walls in haustoria of Cuscuta odorata L. by light microscopy in tissues fixed in a sublimate fixative (30% ethyl alcohol, 30 ml:glacial acetic acid, 10 ml: 65% nitric acid, 1 ml: 40% formaldehyde, 5 ml: oxalic acid, 2 g: mecuric chloride to saturation 2-3 g). Other workers have published electron micrographs of structures transversing the outer epidermal cell in thin sections of plant leaves that have been interpreted as ectodesmata. Such structures are evident following treatment with Hg++ or Ag+ salts and are only rarely observed by electron microscopy. If ectodesmata exist without such treatment, and are not artefacts, they would afford natural pathways of entry for applied foliar solutions and plant viruses.

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An ultrastructural study of vegetative incompatibility in plants

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100083047 ◽

1978 ◽

Vol 36 (2) ◽

pp. 436-437

Author(s):

Randy Moore

Keyword(s):

Ultrastructural Study ◽

Cell Walls ◽

Growth And Development ◽

Solanum Pennellii ◽

Initial Product ◽

Basic Aspect ◽

Tissue Interactions ◽

Graft Interface ◽

Antigen Antibody ◽

Standard Fixation

Cell and tissue interactions are a basic aspect of eukaryotic growth and development. While cell-to-cell interactions involving recognition and incompatibility have been studied extensively in animals, there is no known antigen-antibody reaction in plants and the recognition mechanisms operating in plant grafts have been virtually neglected.An ultrastructural study of the Sedum telephoides/Solanum pennellii graft was undertaken to define possible mechanisms of plant graft incompatibility. Grafts were surgically dissected from greenhouse grown plants at various times over 1-4 weeks and prepared for EM employing variations in the standard fixation and embedding procedure. Stock and scion adhere within 6 days after grafting. Following progressive cell senescence in both Sedum and Solanum, the graft interface appears as a band of 8-11 crushed cells after 2 weeks (Fig. 1, I). Trapped between the buckled cell walls are densely staining cytoplasmic remnants and residual starch grains, an initial product of wound reactions in plants.

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