Variability in ultrastructure of Clostridium botulinum spores

1972 ◽  
Vol 18 (11) ◽  
pp. 1717-1719 ◽  
Author(s):  
Kenneth E. Stevenson ◽  
Reese H. Vaughn
Keyword(s):  
Outer Layer ◽  
Clostridium Botulinum ◽  
Dense Layer ◽  
Spore Coat ◽  
Outer Coat ◽  
Thin Electron

The ultrastructure of spores of Clostridium botulinum strains 78A, 17B (nonproteolytic), and C51C3 was investigated. Electron photomicrographs revealed the following: strain 78A: the oval spores, enveloped by multilayered exosporia, were normally found within swollen sporangia. The spore coat contained a distinct outer layer and a thicker inner coat. Strain 17B: the oval spores were covered by open-ended, sheath-like exosporia. Some spores were enclosed within slightly swollen sporangia, while most were present as free spores. A layered, electron-translucent outer coat and an electron-dense inner coat comprised the spore coat. Strain C51C3: the oval to cylindrical spores were seldom found within intact sporangia. The spore coat was a single, thin, electron-dense layer. Exosporial layers were in apposition to the spore coat.

Ultrastructural studies of primary spores of Conidiobolus, Erynia, and related Entomophthorales

1989 ◽  
Vol 67 (9) ◽  
pp. 2576-2589 ◽  
Author(s):  
J. P. Latgé ◽  
D. F. Perry ◽  
M. C. Prévost ◽  
R. A. Samson
Keyword(s):  
Outer Layer ◽  
Germ Tube ◽  
Spore Wall ◽  
Wall Layer ◽  
Spore Formation ◽  
Dense Layer ◽  
Nuclear Ultrastructure ◽  
Ultrastructural Studies ◽  
Thin Electron ◽  
Definition Of

Wall development during primary spore formation, discharge, and germination of Entomophthorales is emphasized in ultrastructural studies of Conidiobolus, Entomophaga, Neozygites, and Erynia. In the fungi examined, spore and sporophore walls consist of a thick, electron-translucent inner layer and a thin, electron-dense outer layer. During spore formation, cytoplasm of the supporting sporophore cell migrates into the spore initial. As the former cell empties, a septum develops. Discharge is caused by inversion of the papillum, which lacks the electron-dense layer. Only in Erynia did the two spore wall layers separate upon impact. Intracytoplasmic organization of the primary spore is typical of the Zygomycotina; the morphology of organelles was characteristic of species, whereas nuclear ultrastructure was consistent within genera. Conidiobolus nuclei have a prominent nucleolus that lacks heterochromatin, in contrast with the other genera where large patches of heterochromatin were observed. Upon germination, no rupture of the spore outer layer was observed other than at points of germ tube emergence. The germ tube wall was continuous with the inner spore wall layer. The results are discussed in reference to Entomophthorales taxonomy and definition of the terms conidium and monosporous sporangiolum.

Subsidence in the European Area

1934 ◽  
Vol 71 (2) ◽  
pp. 76-85
Author(s):  
R. G. Lewis
Keyword(s):  
Central Europe ◽  
Outer Layer ◽  
The Other ◽  
Dense Layer ◽  
Total Thickness ◽  
Mountainous Regions ◽  
European Area ◽  
The Earth ◽  
Granitic Layer ◽  
Sedimentary Layer

The structure of the earth was supposed by Suess to be tripartite, there was an outer layer of rocks mainly granitic, the sal, or sial as it is usually now called. This rested, or “floated”, on a dense layer called the sima, of basaltic character, within which was the earth’s core, or nife, metallic in nature. Such a simple conception has been modified in the light of later knowledge: geologically there is much evidence pointing to the existence of several shells of increasing density within the crust. This is to some extent supported by the evidence of seismology, the layers below the upper sedimentary layer being the Granitic, the Intermediate (of tachylyte or diorite) and Lower Layers (dunite, peridotite, or eclogite) (1). According to the latest information there are four layers intermediate between the granitic and lower layers: the thickness of the sedimentary layer varies from about 2 to 6 kilometres in mountainous regions: the thickness of the granitic layer varies, being about 10 to 12 kilometres in Central Europe. In low-lying regions the total thickness of these two layers is probably about 6 kilometres less than in mountainous regions: “the thicknesses of the other layers are very difficult to determine; the upper two probably have together a thickness of about 15 kilometres, but the others can hardly be determined from the observations” (2).

scholarly journals Localization of Proteins to Different Layers and Regions of Bacillus subtilis Spore Coats

2009 ◽  
Vol 192 (2) ◽  
pp. 518-524 ◽  
Author(s):  
Daisuke Imamura ◽  
Ritsuko Kuwana ◽  
Hiromu Takamatsu ◽  
Kazuhito Watabe
Keyword(s):  
Bacillus Subtilis ◽  
Mother Cell ◽  
Fluorescent Proteins ◽  
Bacterial Spores ◽  
Spore Coat ◽  
Subtilis Spore ◽  
Proximal Pole ◽  
Outer Coat ◽  
Outermost Layer ◽  
Bacillus Subtilis Spore

ABSTRACT Bacterial spores are encased in a multilayered proteinaceous shell known as the coat. In Bacillus subtilis, over 50 proteins are involved in spore coat assembly but the locations of these proteins in the spore coat are poorly understood. Here, we describe methods to estimate the positions of protein fusions to fluorescent proteins in the spore coat by using fluorescence microscopy. Our investigation suggested that CotD, CotF, CotT, GerQ, YaaH, YeeK, YmaG, YsnD, and YxeE are present in the inner coat and that CotA, CotB, CotC, and YtxO reside in the outer coat. In addition, CotZ and CgeA appeared in the outermost layer of the spore coat and were more abundant at the mother cell proximal pole of the forespore, whereas CotA and CotC were more abundant at the mother cell distal pole of the forespore. These polar localizations were observed both in sporangia prior to the release of the forespore from the mother cell and in mature spores after release. Moreover, CotB was observed at the middle of the spore as a ring- or spiral-like structure. Formation of this structure required cotG expression. Thus, we conclude not only that the spore coat is a multilayered assembly but also that it exhibits uneven spatial distribution of particular proteins.

scholarly journals The fission yeast spore is coated by a proteinaceous surface layer comprising mainly Isp3

2014 ◽  
Vol 25 (10) ◽  
pp. 1549-1559 ◽  
Author(s):  
Kana Fukunishi ◽  
Kana Miyakubi ◽  
Mitsuko Hatanaka ◽  
Natsumi Otsuru ◽  
Aiko Hirata ◽  
...  
Keyword(s):  
Fission Yeast ◽  
Digestive Enzymes ◽  
Spore Wall ◽  
Environmental Stresses ◽  
Dense Layer ◽  
Spore Coat ◽  
Spore Surface ◽  
Wild Type ◽  
Dormant Cell ◽  
Spore Coat Protein

The spore is a dormant cell that is resistant to various environmental stresses. As compared with the vegetative cell wall, the spore wall has a more extensive structure that confers resistance on spores. In the fission yeast Schizosaccharomyces pombe, the polysaccharides glucan and chitosan are major components of the spore wall; however, the structure of the spore surface remains unknown. We identify the spore coat protein Isp3/Meu4. The isp3 disruptant is viable and executes meiotic nuclear divisions as efficiently as the wild type, but isp3∆ spores show decreased tolerance to heat, digestive enzymes, and ethanol. Electron microscopy shows that an electron-dense layer is formed at the outermost region of the wild-type spore wall. This layer is not observed in isp3∆ spores. Furthermore, Isp3 is abundantly detected in this layer by immunoelectron microscopy. Thus Isp3 constitutes the spore coat, thereby conferring resistance to various environmental stresses.

scholarly journals Role of SP65 in Assembly of the Dictyostelium discoideum Spore Coat

2007 ◽  
Vol 6 (7) ◽  
pp. 1137-1149 ◽  
Author(s):  
Talibah Metcalf ◽  
Hanke van der Wel ◽  
Ricardo Escalante ◽  
Leandro Sastre ◽  
Christopher M. West
Keyword(s):  
Cell Surface ◽  
Dictyostelium Discoideum ◽  
Outer Layer ◽  
Fluorescent Protein ◽  
De Novo ◽  
Middle Layer ◽  
In Vivo Studies ◽  
Permeability Barrier ◽  
Spore Coat

ABSTRACT Like the cyst walls of other protists, the spore coat of Dictyostelium discoideum is formed de novo to protect the enclosed dormant cell from stress. Spore coat assembly is initiated by exocytosis of protein and polysaccharide precursors at the cell surface, followed by the infusion of nascent cellulose fibrils, resulting in an asymmetrical trilaminar sandwich with cellulose filling the middle layer. A molecular complex consisting of cellulose and two proteins, SP85 and SP65, is associated with the inner and middle layers and is required for proper organization of distinct proteins in the outer layer. Here we show that, unlike SP85 and other protein precursors, which are stored in prespore vesicles, SP65 is, like cellulose, synthesized just in time. By tagging the SP65 locus with green fluorescent protein, we find that SP65 is delivered to the cell surface via largely distinct vesicles, suggesting that separate delivery of components of the cellulose-SP85-SP65 complex regulates its formation at the cell surface. In support of previous in vivo studies, recombinant SP65 and SP85 are shown to interact directly. In addition, truncation of SP65 causes a defect of the outer layer permeability barrier as seen previously for SP85 mutants. These observations suggest that assembly of the cellulose-SP85-SP65 triad at the cell surface is biosynthetically regulated both temporally and spatially and that the complex contributes an essential function to outer layer architecture and function.

Ultrastructure of Staphylococcus epidermidis after freeze-etching and thin sectioning

1973 ◽  
Vol 19 (2) ◽  
pp. 294-295
Author(s):  
James E. Gilchrist ◽  
Irving W. DeVoe
Keyword(s):  
Staphylococcus Aureus ◽  
Outer Layer ◽  
Staphylococcus Epidermidis ◽  
Cell Walls ◽  
Cytoplasmic Membrane ◽  
Middle Layer ◽  
Dense Layer ◽  
Thin Sections ◽  
Thin Sectioning ◽  
Freeze Etching

A considerable quantity of information is now available on the ultrastructure of Staphylococcus (1, 2, 4, 7, 8, 10, 11, 12). Cell walls of these organisms in thin sections have been shown to consist of three layers: a dense outer layer, a rather electron translucent middle layer, and a very dense layer next to the cytoplasmic membrane (2, 7, 11, 12). Bulger and Bulger (2) have pointed out the presence of circumferential substructure in the middle layer of the wall in a strain of Staphylococcus aureus isolated as the causative agent in fatal pneumonia.Numerous mesosomes of both the vesicular and laminar types are evident in thin sections of staphylococci from several studies (1, 4, 7, 11). Moreover, single vesicular structures that appear to be invaginations of the trilaminar cytoplasmic membrane have been pointed out by Suganuma (11) and Beaton (1).

Ultrastructure of basidiospore germination in Fomes fomentarius

1978 ◽  
Vol 56 (22) ◽  
pp. 2865-2872 ◽  
Author(s):  
Ichiko Tsuneda ◽  
Lorene L. Kennedy
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Germ Tube ◽  
Early Stage ◽  
Dense Layer ◽  
Lipid Bodies ◽  
Fomes Fomentarius ◽  
Additional Cell ◽  
Thin Electron ◽  
Germ Tubes

Germination of basidiospores in Fomes fomentarius (Fries) Kickx is bipolar with germ tubes emerging at both ends. Ungerminated spores are smooth with a thick cell wall consisting of two layers: an outer thin, electron-dense layer and an inner thick, electron-light layer. During the early stage of germination, two additional cell wall layers are formed: a very thin, electron-dense layer and a relatively thick, electron-light layer. Germ tube walls originate from these newly formed, inner layers. Ungerminated spores are uninucleate and contain numerous lipid bodies, ribosomes, and cisternae of endoplasmic reticulum. Germinated spores have distinct mitochondria and an invaginated plasma membrane and are usually devoid of endoplasmic reticulum.

scholarly journals The Timing of cotE Expression Affects Bacillus subtilis Spore Coat Morphology but Not Lysozyme Resistance

2006 ◽  
Vol 189 (6) ◽  
pp. 2401-2410 ◽  
Author(s):  
Teresa Costa ◽  
Mónica Serrano ◽  
Leif Steil ◽  
Uwe Völker ◽  
Charles P. Moran ◽  
...  
Keyword(s):  
Gene Expression ◽  
Bacillus Subtilis ◽  
Mother Cell ◽  
Spore Coat ◽  
Outer Coat ◽  
Bacillus Subtilis Spore ◽  
Spore Resistance ◽  
Early Expression ◽  
Cell Gene Expression ◽  
Coat Layer

ABSTRACT The synthesis of structural components and morphogenetic factors required for the assembly of the Bacillus subtilis spore coat is governed by a mother cell-specific transcriptional cascade. The first two temporal classes of gene expression, which involve RNA polymerase sigma σE factor and the ancillary regulators GerR and SpoIIID, are deployed prior to engulfment of the prespore by the mother cell. The two last classes rely on σK, whose activation follows engulfment completion, and GerE. The cotE gene codes for a morphogenetic protein essential for the assembly of the outer coat layer and spore resistance to lysozyme. cotE is expressed first from a σE-dependent promoter and, in a second stage, from a promoter that additionally requires SpoIIID and that remains active under σK control. CotE localizes prior to engulfment completion close to the surface of the developing spore, but formation of the outer coat is a late, σK-controlled event. We have transplanted cotE to progressively later classes of mother cell gene expression. This created an early class of mutants in which cotE is expressed prior to engulfment completion and a late class in which expression of cotE follows the complete engulfment of the prespore. Mutants of the early class assemble a nearly normal outer coat structure, whereas mutants of the late class do not. Hence, the early expression of CotE is essential for outer coat assembly. Surprisingly, however, all mutants were fully resistant to lysozyme. The results suggest that CotE has genetically separable functions in spore resistance to lysozyme and spore outer coat assembly.

scholarly journals FORMATION AND STRUCTURE OF THE SPORE OF BACILLUS COAGULANS

1962 ◽  
Vol 14 (1) ◽  
pp. 111-123 ◽  
Author(s):  
D. F. Ohye ◽  
W. G. Murrell
Keyword(s):  
Electron Microscopy ◽  
Epoxy Resin ◽  
Outer Membrane ◽  
Cytoplasmic Membrane ◽  
Developmental Stages ◽  
Mature Spore ◽  
Bacillus Coagulans ◽  
Spore Coat ◽  
Outer Coat ◽  
Embedding Technique

Spore formation in Bacillus coagulans has been studied by electron microscopy using an epoxy resin (Araldite) embedding technique. The developmental stages from the origin of the initial spore septum to the mature spore were investigated. The two forespore membranes developed from the double layer of cytoplasmic membrane. The cortex was progressively deposited between these two membranes. The inner membrane finally became the spore protoplasmic membrane, and the outer membrane part of the inner spore coat or the outer spore coat itself. In the mature spore the completed integuments around the spore protoplasm consisted of the cortex, a laminated inner coat, and a dense outer coat. No exosporium was observed. The method of formation of the cortex and the spore coats is discussed.

Localization of melanin in appressoria of Colletotrichum lagenarium

1986 ◽  
Vol 32 (3) ◽  
pp. 280-282 ◽  
Author(s):  
Y. Kubo ◽  
I. Furusawa
Keyword(s):  
Microscopic Observation ◽  
Parent Strain ◽  
Electron Microscopic Observation ◽  
Dense Layer ◽  
Electron Microscopic ◽  
Colletotrichum Lagenarium ◽  
Albino Mutant ◽  
Thin Electron

The location of melanin in appressoria of Colletotrichum lagenarium was determined by ultrastructural comparison of the parent strain 104-T, an albino mutant 79215, and an albino mutant 79215 treated with scytalone, a melanin precursor in this fungus. Melanin in appressoria of the parent strain 104-T and that of albino mutant 79215 treated with scytalone was located external to the plasmalemma as a smooth, thin, electron-dense layer. A comparable layer was not observed in appressoria of the albino mutant 79215 without scytalone. Electron microscopic observation of a median section of pigmented appressoria of albino mutant 79215 treated with scytalone indicated that the melanized layer extended over the appressoria with the exception of the pore which provides an opening for the emergence of the infection peg.

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