Ultrastructural aspects of spore germination and outgrowth in Clostridium sporogenes

1969 ◽  
Vol 15 (9) ◽  
pp. 1061-1065 ◽  
Author(s):  
Judith F. M. Hoeniger ◽  
C. L. Headley
Keyword(s):  
Cell Wall ◽  
Early Stage ◽  
Nuclear Material ◽  
Spore Coat ◽  
Clostridium Sporogenes ◽  
Thin Sections ◽  
Young Cell ◽  
The Core ◽  
Resting Spore ◽  
Peripheral Areas

The process by which dormant spores of Clostridium sporogenes are transformed into vegetative cells has been studied in thin sections with the electron microscope. The resting spore appears very similar to that of other Bacillaceae for it possesses a rather featureless core which is surrounded by a core membrane, cortex, and spore coat(s); beyond lies a sac-like exosporium. At an early stage in germination the core becomes differentiated into peripheral areas of nuclear material and a ribosome-packed cytoplasm; a germ cell wall develops beyond the core membrane. The later stages of germination coincide with the beginning of outgrowth: the cortex disintegrates into a sponge-like mass of fibrils, and the young cell grows while still retained within the unbroken spore coats. The young cell now has a fibrillar nucleoplasm, a ribosome-rich cytoplasm, an occasional mesosome, a plasma membrane, and a relatively thick cell wall. Subsequently, the cortex vanishes completely, and the new vegetative cell elongates and finally emerges terminally through the spore coats and the exosporium. The exosporium of C. sporogenes consists of two layers: a thick inner one which is laminated, and a thin outer one possessing a fringe of hair-like projections.

ELECTRON MICROSCOPY OF ULTRATHIN SECTIONS OF MICROCOCCUS CRYOPHILUS

1966 ◽  
Vol 12 (3) ◽  
pp. 465-469 ◽  
Author(s):  
K. Mazanec ◽  
M. Kocur ◽  
T. Martinec
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Micrococcus Luteus ◽  
Nuclear Material ◽  
Granular Structure ◽  
Condensed Chromatin ◽  
Thin Sections ◽  
Ultrathin Sections

Ultra thin sections of Micrococcus cryophilus cells were investigated. The cell wall, consisting of several layers, measures 410–500 Å and is covered with a distinct capsule. The cytoplasm, which is of granular structure, includes ribosomes, condensed chromatin, and occasionally mesosomes. The nuclear material has various shapes and is formed by filaments proceeding in various directions. We could find no evidence to bear out the supposition of Kocur and Martinec (1962) that M. cryophilus is related to Micrococcus luteus. M. cryophilus is, in its structure as well as its groupings of cells, different from micrococci, which leads us to believe that it does not belong to the genus Micrococcus.

scholarly journals THE FINE STRUCTURE OF STALKED BACTERIA BELONGING TO THE FAMILY CAULOBACTERACEAE

1964 ◽  
Vol 23 (3) ◽  
pp. 587-607 ◽  
Author(s):  
Jeanne L. Stove Poindexter ◽  
Germaine Cohen-Bazire
Keyword(s):  
Cell Wall ◽  
Fine Structure ◽  
Cell Membrane ◽  
Multilayered Structure ◽  
Gram Negative Bacteria ◽  
Thin Sections ◽  
Gram Negative ◽  
Cytoplasmic Region ◽  
The Core ◽  
The Family

The fine structure of a series of stalked bacteria belonging to the genera Caulobacter and Asticcacaulis has been examined in thin sections. The cell wall has the multilayered structure typical of many Gram-negative bacteria, and continues without interruption throughout the length of the stalk. The core of the stalk, continuous with the cytoplasmic region of the cell, is enclosed in an extension of the cell membrane, and contains a system of internal membranes: it is devoid of ribosomes and nucleoplasm. A membranous organelle occupies the juncture of stalk and cell, separating the ribosomal region from the core of the stalk. Typical mesosomes also occur in the cell, being particularly frequent at the plane of division. The secreted holdfast is located at the tip of the stalk in Caulobacter, and at the pole of the cell adjacent to the stalk in Asticcacaulis.

scholarly journals Fine Structure of Bacillus subtilis

1959 ◽  
Vol 5 (1) ◽  
pp. 129-133 ◽  
Author(s):  
Kiyoteru Tokuyasu ◽  
Eichi Yamada
Keyword(s):  
Bacillus Subtilis ◽  
Early Stage ◽  
Complex Structure ◽  
Mature Spore ◽  
Middle Layer ◽  
Nuclear Material ◽  
Subsequent Stage ◽  
Spore Coat ◽  
Thin Membranes ◽  
Two Envelopes

The sporulation process in Bacillus subtilis has been studied principally with KMnO4 fixation, but also, for the purpose of comparison, with OsO4 and mixtures of both fixatives. At a very early stage, the pre-spore is seen to consist of what seems to be the nuclear material and granular substance, surrounded by a layer of dense material destined to become the innermost layer of the spore coat. At a subsequent stage, a light interspace is observed that is destined to become the spore cortex. The mature spore shows a very complex structure. The spore coat is composed of three layers, the middle layer of which consisted of 5 to 8 lamellae of thin membranes and interspaces, both about 20 to 25 A thick. Between the inner layer of the spore coat and the spore cortex, a thin membrane with an affinity to the cortex can be observed. The spore coat is enclosed within two envelopes, one loosely surrounding the core, and the other adhering to it. The process of spore maturation has been studied in detail. Certain peculiar cellular structures have been observed that seemed to represent features of abnormal sporulation processes.

scholarly journals THE FINE STRUCTURE AND MODE OF ATTACHMENT OF THE SHEATHED FLAGELLUM OF VIBRIO METCHNIKOVII

1963 ◽  
Vol 18 (2) ◽  
pp. 327-336 ◽  
Author(s):  
Audrey M. Glauert ◽  
D. Kerridge ◽  
R. W. Horne
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Thin Sections ◽  
Basal Disc ◽  
The Core ◽  
Thin Sectioning ◽  
Potassium Phosphotungstate ◽  
Mode Of Attachment

The sheathed flagellum of Vibrio metchnikovii was chosen for a study of the attachment of the flagellum to the bacterial cell. Normal and autolysed organisms and isolated flagella were studied by electron microscopy using the techniques of thin sectioning and negative staining. The sheath of the flagellum has the same layered structure as the cell wall of the bacterium, and in favourable thin sections it appears that the sheath is a continuation of the cell wall. After autolysis the sheath is usually absent and the core of the flagellum has a diameter of 120 A. Electron micrographs of autolysed bacteria negatively stained with potassium phosphotungstate show that the core ends in a basal disc just inside the plasma membrane. The basal disc is about 350 A in diameter and is thus considerably smaller than the "basal granules" described previously by other workers.

scholarly journals Sporulation in Bacillus subtilis. Morphological changes

1968 ◽  
Vol 109 (5) ◽  
pp. 819-824 ◽  
Author(s):  
D. Kay ◽  
S. C. Warren
Keyword(s):  
Bacillus Subtilis ◽  
Heat Resistance ◽  
Early Stage ◽  
Morphological Changes ◽  
Dipicolinic Acid ◽  
Close Contact ◽  
Spore Coat ◽  
Serial Sections ◽  
Filament Formation ◽  
Thin Sections

1. When Bacillus subtilis was grown in a medium in which sporulation occurred well-defined morphological changes were seen in thin sections of the cells. 2. Over a period of 7·5hr. beginning 2hr. after the initiation of sporulation the following major stages were observed: axial nuclear-filament formation, spore-septum formation, release of the fore-spore within the cell, development of the cortex around the fore-spore, the laying down of the spore coat and the completion of the corrugated spore coat before release of the spore from the mother cell. 3. The appearance of refractile bodies and 2,6-dipicolinic acid and the development of heat-resistance began between 5 and 6·5hr. after initiation of sporulation. 4. The appearance of 2,6-dipicolinic acid and the onset of refractility appeared to coincide with a diminution of electron density in the spore core and cortex. 5. Heat-resistance was associated with the terminal stage, the completion of the spore coat. 6. The spore coat was composed of an inner and an outer layer, each of which consisted of three or four electron-dense laminae. 7. Serial sections through cells at an early stage of sporulation showed that the membranes of each spore septum were always continuous with the membranes of a mesosome, which was itself in close contact with the bacterial or spore nucleoid. 8. These changes were correlated with biochemical events occurring during sporulation.

scholarly journals New methods for confocal imaging of infection threads in crop and model legumes

Plant Methods ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Angus E. Rae ◽  
Vivien Rolland ◽  
Rosemary G. White ◽  
Ulrike Mathesius
Keyword(s):  
Cell Wall ◽  
Root Hair ◽  
Periodic Acid ◽  
Confocal Imaging ◽  
Wall Material ◽  
Future Research ◽  
Thin Sections ◽  
New Methods ◽  
Infection Threads ◽  
Imaging Of Infection

Abstract Background The formation of infection threads in the symbiotic infection of rhizobacteria in legumes is a unique, fascinating, and poorly understood process. Infection threads are tubes of cell wall material that transport rhizobacteria from root hair cells to developing nodules in host roots. They form in a type of reverse tip-growth from an inversion of the root hair cell wall, but the mechanism driving this growth is unknown, and the composition of the thread wall remains unclear. High resolution, 3-dimensional imaging of infection threads, and cell wall component specific labelling, would greatly aid in our understanding of the nature and development of these structures. To date, such imaging has not been done, with infection threads typically imaged by GFP-tagged rhizobia within them, or histochemically in thin sections. Results We have developed new methods of imaging infection threads using novel and traditional cell wall fluorescent labels, and laser confocal scanning microscopy. We applied a new Periodic Acid Schiff (PAS) stain using rhodamine-123 to the labelling of whole cleared infected roots of Medicago truncatula; which allowed for imaging of infection threads in greater 3D detail than had previously been achieved. By the combination of the above method and a calcofluor-white counter-stain, we also succeeded in labelling infection threads and plant cell walls separately, and have potentially discovered a way in which the infection thread matrix can be visualized. Conclusions Our methods have made the imaging and study of infection threads more effective and informative, and present exciting new opportunities for future research in the area.

scholarly journals FINE STRUCTURE OF THE GRAM-NEGATIVE BACTERIUM ACETOBACTER SUBOXYDANS

1964 ◽  
Vol 20 (2) ◽  
pp. 217-233 ◽  
Author(s):  
G. W. Claus ◽  
L. E. Roth
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Cell Walls ◽  
Negative Staining ◽  
Homogeneous Layer ◽  
Physical Treatment ◽  
Thin Sections ◽  
Gram Negative ◽  
Acetobacter Suboxydans ◽  
Negative Cell

The morphological features of the cell wall, plasma membrane, protoplasmic constituents, and flagella of Acetobacter suboxydans (ATCC 621) were studied by thin sectioning and negative staining. Thin sections of the cell wall demonstrate an outer membrane and an inner, more homogeneous layer. These observations are consistent with those of isolated, gram-negative cell-wall ghosts and the chemical analyses of gram-negative cell walls. Certain functional attributes of the cell-wall inner layer and the structural comparisons of gram-negative and gram-positive cell walls are considered. The plasma membrane is similar in appearance to the membrane of the cell wall and is occasionally found to be folded into the cytoplasm. Certain features of the protoplasm are described and discussed, including the diffuse states of the chromatinic material that appear to be correlated with the length of the cell and a polar differentiation in the area of expected flagellar attachment. Although the flagella appear hollow in thin sections, negative staining of isolated flagella does not substantiate this finding. Severe physical treatment occasionally produces a localized penetration into the central region of the flagellum, the diameter of which is much smaller then that expected from sections. A possible explanation of this apparent discrepancy is discussed.

Spatial Convergence in Height in Central Europe, 1890-1910

2009 ◽  
pp. 90
Author(s):  
Marek Brabec ◽  
John Komlos
Keyword(s):  
Global Economy ◽  
Well Being ◽  
Habsburg Monarchy ◽  
The Core ◽  
Military Recruits ◽  
Convergence Clubs ◽  
Spatial Convergence ◽  
Physical Stature ◽  
The Difference ◽  
Peripheral Areas

We examine spatial convergence in biological well-being in the Habsburg Monarchy, circa 1890-1910, on the basis of evidence of the physical stature of 21-year-old military recruits, disaggregated into 15 Districts. We find that the shorter the population in 1890, the faster its height grew thereafter. Hence, there was convergence in physical stature between the peripheral areas of the monarchy (located in today’s Poland/Ukraine, Romania, and Slovakia) and its core (located in today’s Austria, Czech Republic, and Hungary). The difference in trends between the trend in height in the Polish District of Przemysl and in Vienna was about 0.9 cm per decade, in favor of the former. Convergence among the core Districts themselves was minimal or non-existent, whereas the convergence among the peripheral Districts was more pronounced. Spatial convergence also took place between the peripheral regions and the more developed ones. The pattern is somewhat reminiscent of modern findings on convergence clubs in the global economy.

Die Bahnhofsmission – Ort gelebter Ökumene. Theologische Reflexionen

2021 ◽  
Vol 81 (4) ◽  
pp. 286-296
Author(s):  
Dorothea Sattler
Keyword(s):  
Social Change ◽  
Early Stage ◽  
Individual Case ◽  
Self Reflection ◽  
Threshold Concept ◽  
The Core ◽  
Low Threshold

Abstract This article examines the questions of why the ›Bahnhofsmission‹ is suitable as a seismograph of social change, how it performs this function, what it can achieve and where its limits lie. This is done with the help of self-reflection of the practice of the ›Bahnhofsmission‹ and by unfolding practical examples. The seismograph function is described as a task of the ›Bahnhofsmission‹ that goes beyond the core of individual case assistance and is of benefit to society as a whole. This involves drawing attention to changes at an early stage in order to identify structures of poverty and injustice as causes of need for help as well as of exclusion and to contribute to the elimination of those structures. Due to their location at the station and their open, low-threshold concept, ›Bahnhofsmissionen‹ have an excellent seismographic potential. Where they succeed in raising this potential, they can become incubators for innovation.

Sign in / Sign up

Export Citation Format

Share Document