scholarly journals THE COMPOSITION AND STRUCTURE OF BACTERIAL SPORES

1963 ◽  
Vol 16 (3) ◽  
pp. 579-592 ◽  
Author(s):  
A. D. Warth ◽  
D. F. Ohye ◽  
W. G. Murrell
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Heat Resistance ◽  
Dipicolinic Acid ◽  
Diaminopimelic Acid ◽  
Bacterial Spores ◽  
Bacillus Species ◽  
Thin Sections ◽  
Composition And Structure ◽  
Soluble Fractions

The composition of the insoluble "integuments" and soluble "contents" fractions of spores of four Bacillus species of widely differing heat resistance were compared. Electron microscopy of thin sections was also used to determine and compare the morphological structures in the integument preparations. The soluble fractions of the thermophiles, B. coagulans and B. stearothermophilus, had a higher content of hexose and dipicolinic acid. The hexose content of both fractions of the four species was related to heat resistance. Integument fractions consisted chiefly of protein together with variable amounts of the mucopeptide constituents, α, ϵ-diaminopimelic acid (DAP) and hexosamine. In the thermophiles the DAP and hexosamine were found chiefly in the insoluble integuments fractions, while in B. cereus and B. subtilis most of this material was soluble. Integument preparations, containing mainly protein with little mucopeptide, consisted chiefly of outer and inner spore coats, while preparations having more mucopeptide contained also residual cortical material and a cortical membrane (possibly the germ cell wall). The results suggest that spore integuments consist of mainly proteinaceous outer and inner coats together with variable amounts of residual cortex and cortical membrane which contain the mucopeptide material.

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.

Dimorphism of Penicillium marneffei as observed by electron microscopy

1973 ◽  
Vol 19 (10) ◽  
pp. 1305-1309 ◽  
Author(s):  
Robert G. Garrison ◽  
Karen S. Boyd
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Penicillium Marneffei ◽  
Lipid Bodies ◽  
Hyphal Cell ◽  
Dimorphic Fungi ◽  
Thin Sections ◽  
Internal Morphology ◽  
Tissue Phase ◽  
Altered Lipid

Aspects of the culturally induced mycelial- to tissue-phase transformation of Penicillium marneffei were studied by electron microscopy of thin sections. The hyphal cell was observed to contain multiple, large lipid bodies scattered throughout the cytoplasm. Five days after induction of conversion, short elements arose which were characterized by the presence of two polar areas of vacuolation containing electron-opaque material thought to be altered lipid. This material could not be demonstrated with permanganate fixation, but reacted strongly with thiocarbohydrazide. The latter reagent is known to enhance the electron density of osmium-stained lipids. After 10 days incubation, the tissue-phase cells appeared to be slightly elongate with one or more septa present as the result of division by fission. The cell wall appeared to be of uniform electron opacity with a slightly roughened appearance to the outer surface. Except for residuals of polar vacuolation, the internal morphology of the tissue phase of P. marneffei appeared similar in many respects to that of the analogous yeast-like phases of certain other of the pathogenic dimorphic fungi.

Atomistic Study of Wet-heat Resistance of Calcium Dipicolinate in the Core of Spores

MRS Advances ◽  
2018 ◽  
Vol 3 (26) ◽  
pp. 1457-1462
Author(s):  
Ankit Mishra ◽  
Pankaj Rajak ◽  
Subodh Tiwari ◽  
Chunyang Sheng ◽  
Aravind Krishnamoorthy ◽  
...  
Keyword(s):  
Heat Resistance ◽  
Dipicolinic Acid ◽  
Bacterial Spores ◽  
Water Molecules ◽  
Confined Water ◽  
Reactive Molecular Dynamics ◽  
Wet Heat ◽  
Experimental Findings ◽  
Core Simulation ◽  
Solid Liquid

ABSTRACTThe extreme heat resistance of dormant bacterial spores strongly depends on the extent of protoplast dehydration and the concentration of dipicolinic acid (DPA) and its associated calcium salts (Ca-DPA) in the spore core. Recent experiments have suggested that this heat resistance depends on the properties of confined water molecules in the hydrated Ca-DPA-rich protoplasm, but atomistic details have not been elucidated. In this study, we used reactive molecular dynamics (RMD) simulations to study the dynamics of water in hydrated DPA and Ca-DPA as a function of temperature. The RMD simulations indicate two distinct solid-liquid and liquid-gel transitions for the spore core. Simulation results reveal monotonically decreasing solid-gel-liquid transition temperatures with increasing hydration. Additional calculations on the specific heat and free energy of water molecules in the spore core further support the higher heat resistance of dehydrated spores. These results provide an insight into the experimental trend of moist-heat resistance of bacterial spores and reconciles previous conflicting experimental findings on the state of water in bacterial spores.

scholarly journals Superdormant Spores of Bacillus Species Have Elevated Wet-Heat Resistance and Temperature Requirements for Heat Activation

2009 ◽  
Vol 191 (18) ◽  
pp. 5584-5591 ◽  
Author(s):  
Sonali Ghosh ◽  
Pengfei Zhang ◽  
Yong-qing Li ◽  
Peter Setlow
Keyword(s):  
Heat Resistance ◽  
Dipicolinic Acid ◽  
Bacillus Species ◽  
Activation Temperature ◽  
New Information ◽  
Temperature Requirements ◽  
Wet Heat ◽  
Dormant Spore ◽  
Heat Activation ◽  
Temperature Optima

ABSTRACT Purified superdormant spores of Bacillus cereus, B. megaterium, and B. subtilis isolated after optimal heat activation of dormant spores and subsequent germination with inosine, d-glucose, or l-valine, respectively, germinate very poorly with the original germinants used to remove dormant spores from spore populations, thus allowing isolation of the superdormant spores, and even with alternate germinants. However, these superdormant spores exhibited significant germination with the original or alternate germinants if the spores were heat activated at temperatures 8 to 15°C higher than the optimal temperatures for the original dormant spores, although the levels of superdormant spore germination were not as great as those of dormant spores. Use of mixtures of original and alternate germinants lowered the heat activation temperature optima for both dormant and superdormant spores. The superdormant spores had higher wet-heat resistance and lower core water content than the original dormant spore populations, and the environment of dipicolinic acid in the core of superdormant spores as determined by Raman spectroscopy of individual spores differed from that in dormant spores. These results provide new information about the germination, heat activation optima, and wet-heat resistance of superdormant spores and the heterogeneity in these properties between individual members of dormant spore populations.

Characterization of the cell wall of Butyrivibrio species

1993 ◽  
Vol 39 (10) ◽  
pp. 912-921 ◽  
Author(s):  
R. B. Hespell ◽  
K. Kato ◽  
J. W. Costerton
Keyword(s):  
Cell Wall ◽  
Diaminopimelic Acid ◽  
Wall Structure ◽  
Phenotypic Properties ◽  
Cytoplasmic Inclusions ◽  
Thin Sections ◽  
Positive Type ◽  
Butyrivibrio Fibrisolvens ◽  
Dna Relatedness ◽  
Molar Ratios

Most Butyrivibrio strains have been isolated from the gastrointestinal tract of animals and have been classified as Butyrivibrio fibrisolvens. A few strains isolated from human feces are designated as Butyrivibrio crossatus, the other species in this genus. Butyrivibrio fibrisolvens strains are anaerobic, curved rods that produce butyrate, but numerous studies have shown that these strains display considerable variations in phenotypic properties and heterogeneity in DNA relatedness. Although over 60 strains have been characterized in these respects, the cell wall structure of only a few strains has been studied. In this study, cell wall related properties of 12 strains representative of five DNA relatedness groups were examined. All strains were very sensitive to penicillin and other antibiotics that interfere with cell wall synthesis. Although an occasional resistant strain was found, most strains were sensitive to a variety of protein synthesis antibiotics that included aminoglycosides and tetracycline. In contrast, all strains were highly resistant to nalidixic acid. Peptidoglycans were isolated from seven B. fibrisolvens strains and Lachnospira multiparus. Compositional analyses indicated molar ratios of 0.7:2:2:1:0.8 for muramic acid, glucosamine, alanine, glutamic acid, and diaminopimelic acid, respectively, in all peptidoglycans, which also showed a low degree of cross-linking. A trichloroacetic acid extractable galactosamine-containing polysaccharide copurified with the Butyrivibrio peptidoglycans. Electron microscopy of thin sections showed all strains to possess a Gram-positive type of cell wall that was atypically thin (12–18 nm). Most strains also displayed external (surface) polysaccharide layers. Cytoplasmic inclusions and granules were evident in many strains and were composed of polysaccharides, on the basis of cell composition analyses. The findings that Butyrivibrio strains have overall similarities in cell wall properties, but differences in DNA relatedness, suggest that these organisms should be classified as several more species in the same genus or family.Key words: Butyrivibrio fibrisolvens, Butyrivibrio crossatus, cell wall, peptidoglycan, ruminal bacteria.

Fine structure of Arthrobacter crystallopoietes during long-term starvation of rod and spherical stage cells

1973 ◽  
Vol 19 (1) ◽  
pp. 1-5 ◽  
Author(s):  
Charles W. Boylen ◽  
Jack L. Pate
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Fine Structure ◽  
Cell Size ◽  
Morphological Changes ◽  
Thin Sections ◽  
Size And Shape ◽  
Arthrobacter Crystallopoietes ◽  
Total Starvation

Actively growing spherical and rod-shaped cells of Arthrobacter crystallopoietes were subjected to total starvation in buffer for 8 weeks. At intervals, thin sections of cells were prepared and examined by electron microscopy. Starving cells underwent no morphological changes that would account for their unusual survival capabilities. Cell size and shape remained unaltered. There was no thickening of the cell wall and no development of structures similar to those observed in spores or cysts. As the length of starvation increased, the following changes were observed; glycogen deposits disappeared, the number of ribosome particles decreased, the number of vesicular membranes increased within the cell, and the nucleoplasm expanded in volume to fill the emptying cytoplasm.

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